JP2007282678A - Catheter tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catheter tube capable of easily obtaining a desired gradient of hardness, reducing a sudden change of hardness in a hardness changing part, with excellent push-in property and the kink resistance applicable to various kinds of catheters such as a micro-catheter. <P>SOLUTION: The catheter tube comprises an inner layer 1 made of fluororesin and an outer layer which covers the inner layer. The outer layer comprises at least two layers: a first outer layer 3 with at least two kinds of resin with different hardness in the longitudinal direction of the catheter tube and a second outer layer 4 covering the first outer layer with at least two kinds of resin with different hardness in the longitudinal direction of the catheter tube. The joint part 5 of the two resin parts with different hardness in the first outer layer is not juxtaposed with the joint part 6 of the two resin parts with different hardness in the second outer layer in the longitudinal direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a catheter tube capable of easily obtaining a desired hardness gradient.

  Conventionally, medical procedures such as transcutaneously inserting a catheter inserted into a blood vessel into organs such as the brain, heart, abdomen, etc., administering therapeutic agents, embolic substances, contrast agents, etc., infusion, or sucking thrombus ing. In recent years, due to advances in medicine, it has become necessary to inject therapeutic agents, embolic substances, contrast agents and the like into finer peripheral blood vessels, and the development of catheters that can be inserted into these fine peripheral blood vessels has been desired.

  Since these catheters need to surely advance through a narrow peripheral blood vessel that is tortuous by an operator's operation, various operability is required. This operability includes pushability that reliably transmits the operator's pushing force to the tip of the catheter, torque transmission that reliably transmits the rotational force applied by the operator to the tip of the catheter, and For example, kink resistance that does not cause the catheter to be bent at the bent or curved portion of the blood vessel can be given.

  In order to realize these operability, a technique is adopted in which the distal end portion of the catheter is made of a flexible material, the proximal side is made of a hard material, and a hardness gradient is given in the longitudinal direction. The following methods are mentioned as methods generally taken. First, hollow outer layer tubes having different hardnesses that have been extruded are cut into a predetermined length. The hollow outer layer tube having a certain length is added to and covered with a tube composed of an inner layer and a reinforcing layer (hereinafter referred to as a braided tube) so as to have a necessary hardness gradient. Next, the combination of the braided tube and the hollow outer tube is passed through a heated mold, or a heat shrinkable tube that shrinks by heating is further covered from above the hollow outer tube of the combination. To obtain a catheter tube with a hardness gradient. With this method, a desired hardness gradient can be obtained relatively easily. Further, since the hollow outer tube cut in advance to a certain length is added, the hardness gradient can be freely imparted at a relatively accurate rate.

  However, in the catheter obtained by the above method, a sudden hardness change cannot be denied, particularly at the outer layer seam portion having a different hardness on the tip side that passes through the highly bent portion, and the pushability is not easily lowered due to a sharp decrease in bending rigidity, and it is difficult to bend. There is a drawback that the kink resistance is easily lowered.

Therefore, for example, in Japanese Patent Application Laid-Open No. 3-177682 (Patent Document 2), the joint portion (bonding portion) between the soft resin portion and the hard resin portion is formed of the hard resin layer according to the gradual decrease in the thickness of the soft resin layer. A two-layer structure in which the wall thickness gradually increases and overlaps is disclosed. However, in this two-layer structure, when the difference in hardness between the two resins to be joined is large, the change in hardness becomes large. In addition, as a method for obtaining a continuous hardness gradient, for example, in Japanese Translation of PCT International Publication No. 2003-501160 (Patent Publication 1), the composition ratio of two materials is changed during extrusion, whereby the hardness is increased in the longitudinal direction. A switching extrusion process that varies along the line is disclosed. In this method, the hardness gradient of the resin can be obtained continuously. However, in a catheter that is required to have a small diameter and a thin wall, the resin switching transition part becomes long, and the necessary switching length may not be obtained. In addition, since hardness is usually changed by switching between two types or at most three types of resin, the hardness gradient is limited.
Special table 2003-501160 gazette Japanese Patent Laid-Open No. 3-177682

  An object of the present invention is to provide a pushability and kink resistance that can easily obtain a desired hardness gradient and that can be applied to various catheters including a microcatheter, in which a sudden hardness change in a hardness change portion is reduced. An object of the present invention is to provide an excellent catheter tube.

(1) One feature of the present invention is a catheter tube including an inner layer made of a fluororesin and an outer layer covering the inner layer,
The outer layer is
(A) a first outer layer comprising at least two resins having different hardnesses in the longitudinal direction of the catheter tube; and
(B) having at least two layers of a second outer layer covering the first outer layer (a), comprising at least two resins having different hardnesses in the longitudinal direction of the catheter tube;
The joint portion of two resins having different hardnesses in the first outer layer (a) and the joint portion of two resins having different hardnesses in the second outer layer (b) are in positions not parallel to each other in the longitudinal direction. This is a featured catheter tube.

With the above features, the present invention can provide a catheter tube in which a desired hardness gradient can be obtained relatively easily and a sudden hardness change at the hardness change portion is reduced.
(2) Another feature of the present invention is that the hardness of the resin on the proximal end side of the two resins of the first outer layer (a) is higher than the hardness of the resin on the distal end side, Of the two resins of the outer layer (b), the catheter tube is configured such that the hardness of the resin on the proximal end side is higher than the hardness of the resin on the distal end side.

Due to the above features, the present invention can provide a catheter tube having a flexible distal end and a rigid proximal end.
(3) Another feature of the present invention is a catheter tube including an inner layer and an outer layer covering the inner layer,
The outer layer is
(A) a first outer layer;
(B) a second outer layer covering the first outer layer,
And
The first outer layer (a)
A distal side resin part located on the distal side of the catheter tube, and a proximal side resin part bonded to the distal side resin part and having a hardness higher than that of the distal side resin part,
The second outer layer (b)
The resin part includes at least one resin part, and the resin part has a base end and a base end in order to reduce a variation in bending rigidity due to a difference in hardness between the tip side resin part and the base end side resin part. It is provided in a position that covers the joint with the side resin part,
A catheter tube characterized by
(4) Another feature of the present invention is a catheter characterized in that the catheter tube is included in at least one part.
(5) Another feature of the present invention is a catheter in which the catheter tube is included in a region from the distal end of the catheter to 500 mm in the longitudinal direction.

Due to the above characteristics, the present invention can provide a catheter excellent in kink resistance and pushability particularly on the distal end side.
(6) Another feature of the present invention is that, in the region from the distal end of the catheter in the longitudinal direction to 500 mm, only a portion consisting only of the inner layer and the first outer layer, or only the inner layer, the reinforcing layer, and the first outer layer. A catheter having at least one of the following parts.

Due to the above characteristics, the present invention can provide a catheter having a flexible tip and a small diameter.
(7) Another feature of the present invention is that the catheter is a microcatheter.

  With the above features, the present invention can provide a microcatheter having a flexible tip and a small diameter and excellent kink resistance and pushability.

  Other features of the present invention and their effects will become apparent from the embodiments and drawings described below.

  ADVANTAGE OF THE INVENTION According to this invention, the desired hardness inclination can be obtained comparatively easily, and the catheter tube by which the rapid hardness change in the hardness change part was reduced can be provided.

Hereinafter, a catheter tube as an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
1. 1 is a cross-sectional view (longitudinal cross-sectional view) of a catheter tube as an embodiment of the present invention. The catheter tube of the present embodiment includes an inner layer 1, a reinforcing layer 2, and at least two outer layers (in the drawing, two first outer layers 3 and second outer layers 4).
2. Inner layer The resin constituting the inner layer 1 uses a fluororesin in order to enhance the slidability of the lumen. Examples thereof include polytetrafluoroethylene, polytetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene, tetrafluoroethylene / ethylene copolymer, and the like.
3. Reinforcing layer Examples of the material of the strands included in the reinforcing layer 2 include resin or metal. Examples of resins include polyolefins such as polypropylene and polyethylene, nylon 6, nylon 66, nylon 12, polyamides such as polyamide elastomer, polyesters such as polyethylene terephthalate and polyester elastomer, polyurethane, polyurethane elastomer, aramid, polyarylate, etc. Examples of metals include stainless steel or highly radiopaque materials such as tungsten, platinum, iridium, gold, etc., which may be combined depending on the desired mechanical properties and radiopacity. Good. Further, the reinforcing layer may have a coil structure or a braided structure. FIG. 1 illustrates a braided structure.
4). Outer layer As for the outer layer, each of the first outer layer 3 and the second outer layer includes, for example, polyamides such as nylon 6, nylon 66, nylon 12 and polyamide elastomer, olefins such as polyethylene, polypropylene, polymethyl methacrylate and modified polyolefin, polyethylene terephthalate , Polyesters such as polybutylene terephthalate and polyester elastomer, polyurethane, polyurethane elastomer, polymer blends thereof, polymer alloys and the like.

  The resin material may contain various additives such as a contrast agent, a plasticizer, a reinforcing agent, and a pigment in addition to the polymerization aid used at the time of polymerization.

  The resin to be used for both the first outer layer 3 and the second outer layer 4 is not limited, but it is desirable to use the same resin in order to improve the adhesion between both outer layers. When the resin constituting the first outer layer 3 and the second outer layer 4 is a polyether ester amide elastomer, such as PEBAX (available from Arkema), the Shore D hardness of the polyether ester amide elastomer material is It can be said that it is proportional to the hard segment weight ratio of the amide elastomer material.

The weight ratio of the hard segment was determined by measuring the weight of the polyamide part, the weight of the ester part, and the weight of the polyether part by H ¹ -NMR. Formula: Weight of polyamide part / (weight of polyamide part + ester Part weight + polyether part weight).
4-1. 1st outer layer The 1st outer layer 3 is comprised from the resin from which the hardness in which it differs in at least 2 steps | paragraphs along the longitudinal direction of a catheter tube. Those resins correspond to “the distal end side resin portion located on the distal end side of the catheter tube and the proximal end side resin portion joined to the distal end side resin portion and having a hardness higher than that of the distal end side resin portion”. .

  The resin constituting the catheter of the present invention includes a blend of several kinds of resins or resins having different compositions and the above-mentioned additives. A technology that blends several different types of resins and additives in advance, mixes and forms them, and shows uniform mechanical and thermal characteristics within a general tolerance as one type of resin. It will be clear to the person.

  In other words, “two resins with different hardness (or resins with two different levels of hardness)” here means uniform mechanical characteristics and heat within general tolerances regardless of whether the resins are blended or not. There are two resins that exhibit specific characteristics, and the hardness of each resin is different.

  As shown in FIG. 1, the shape of the joint portion 5 of the first outer layer 3 having different hardnesses in two stages may be a shape that is nearly perpendicular to the longitudinal direction, but has a tapered shape that changes asymptotically. There may be. However, the joint portion 5 is arranged in parallel to a single resin portion of the second outer layer 4 which is different from a position parallel to the joint portion 6 of the second outer layer 4 constituting the outside of the first outer layer 3 in the longitudinal direction. Must be in position.

By shortening the length in the longitudinal direction in which two types of resin are mixed in the joints 5 and 6, it becomes possible to make the joints 5 and 6 closer to each other in the longitudinal direction, and the change in hardness is longitudinal. It can be done in a short range in the direction.
4-2. Second outer layer The second outer layer 4 constituting the outer side of the first outer layer 3 is also composed of resins having at least two stages of different hardness. Those resins cover “a joint part that joins the front end side resin part and the base end side resin part in order to reduce fluctuations in bending rigidity due to hardness differences between the front end side resin part and the base end side resin part. This corresponds to the “resin portion provided at the position”.

Similarly to the shape of the joint portion 6 of the first outer layer 3, the shape of the joint portion 5 of the second outer layer 4 may be a shape that is nearly perpendicular to the longitudinal direction, but is a tapered shape that changes asymptotically. It may be. Further, the joint portion 6 of the second outer layer is parallel to a single resin portion of the first outer layer 3 which is different from the position parallel to the joint portion 5 of the first outer layer 3 inscribed in the second outer layer 4 in the longitudinal direction. It needs to exist in the position to be.
4-3. Effect by Embodiment In this way, each of the joint portion 5 of the first outer layer 3 and the joint portion 6 of the second outer layer 4 is configured so that the position in the length direction is different, so that the abruptness in the hardness changing portion is abrupt. A catheter tube with reduced hardness change is provided.

  As shown in FIG. 2 or FIG. 3, the number of joints included in each outer layer is not limited to one and may be two or more. When the number of joints included in each outer layer is 2 or more, as long as the positions of the two joints are not juxtaposed in the longitudinal direction in a region where it is necessary to suppress a sudden change in hardness, other than such regions Then, the positions of the other two joint portions may be juxtaposed.

  The hardness of the resin constituting the first outer layer 3 and the second outer layer 4 is not particularly limited, but in many catheters to which the catheter tube of the embodiment is applied, the distal end side is made flexible and the proximal end side is made hard, and the distal end side Therefore, the catheter tube is preferably configured so that its hardness increases from the distal end side to the proximal end side in the length direction.

  For example, the shore hardness of each segment (resin part) included in the first outer layer is 20D to 40D, 30D to 65D, and 50D to 80D from the tip side, and the shore hardness of each segment (resin part) included in the second outer layer. Examples include 25D to 45D, 30D to 74D, and 50D to 80D from the front end side.

The difference in hardness between the two resins bonded at the bonding portion 5 or the bonding portion 6 is desirably a Shore D hardness of 30 D or less, more preferably 15 D or less. In the longitudinal direction, there may be a portion where the resin constituting the first outer layer 3 and the resin constituting the second outer layer 4 are part of the same resin, but as described above, The joint portion 6 needs to be present at a position parallel to the single resin portion of the first outer layer 3, which is different from the position parallel to the joint portion 5 of the first outer layer 3 in the longitudinal direction.
4-4. The thickness of the outer layer The thickness of the first outer layer 3 is not particularly defined, but it is desirable that the thickness be constant from the moldability of the second outer layer 4 constituting the outside of the first outer layer 3. On the contrary, the thickness of the second outer layer 4 is desirably thin on the distal end side and thick on the proximal end side in order to impart a hardness gradient more effectively. However, when the thickness change of the second outer layer 4 becomes local, a local hardness change is caused. Therefore, it is desirable that the thickness changes continuously or has an outer diameter changing portion in the same resin.
5). Application of Catheter Tube The catheter tube of the embodiment described above can be applied to any catheter that imparts a hardness gradient in the length direction. 2 and 3 are schematic sectional views of a catheter (corresponding to “the catheter tube is included in at least one part”) to which the catheter tube of the embodiment is applied. The catheter tube of the embodiment is particularly required to have a small diameter and a thin wall, and when applied to a microcatheter where the mechanical rigidity of the resin greatly affects the operation characteristics of the catheter, a remarkable effect can be obtained.

  The catheter tube of the embodiment can be applied to the entire length of the catheter, but can also be applied to a part of the catheter. In particular, it is more desirable to selectively apply the distal end side having a high probability of being inserted into a peripheral blood vessel. At least from the distal end of the catheter, in the region of 500 mm from the distal end position toward the proximal end side, the catheter tube of the example is configured, so that the local rigidity change on the distal end side of the catheter is reduced and bent. Even when passing through a peripheral blood vessel, good pushability can be realized without bending.

  In FIG. 2, the catheter tube of the embodiment is applied over the entire length of the catheter. FIG. 3 illustrates a catheter in which the catheter tube of the embodiment is applied to the distal end side of the catheter and the proximal outer layer 7 is applied to the proximal side.

  FIG. 4 shows a schematic cross-sectional view of the catheter. In order to make the distal end side of the catheter more flexible and thin, a part of the distal end portion of the catheter consisting only of the inner layer and the first outer layer (8 in FIG. 4) or a portion consisting of only the inner layer, the reinforcing layer and the first outer layer (9 in FIG. 4).

  Although not shown, a marker made of a material having high radiopacity, for example, tungsten, platinum, iridium, gold, or the like can be attached to the catheters of the above-described embodiments as necessary.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail according to an Example, this invention is not limited to a following example.

Example 1
A silver plated annealed copper wire having a diameter of 0.52 mm was coated with polytetrafluoroethylene (PTFE) (corresponding to “inner layer”) with a thickness of 0.020 mm to obtain a core material. A stainless steel fine wire (round wire, diameter 0.020 mm) (corresponding to “reinforcing layer”) was wound around the core material in a state where the wires were arranged side by side to prepare a braided tube.

  A hollow tube made of a resin (polyamide elastomer, PEBAX, manufactured by Arkema), which is the first outer layer shown in Table 1 obtained in advance by extrusion molding, is sequentially covered on the above-mentioned braided tube. A heat-shrinkable tube made of a fluoropropylene copolymer (FEP) was placed on the tube, placed in a heating furnace, and heat-shrinked to obtain a first outer layer. Next, a hollow tube made of a resin constituting the second outer layer shown in Table 1 is sequentially covered on the first outer layer, and a heat-shrinkable tube made of tetrafluoroethylene-hexafluoropropylene copolymer (FEP) is formed thereon. Covered and placed in a heating furnace and heat-shrinked to obtain a catheter tube.

  The outer diameters of the first outer layer and the second outer layer of the obtained catheter tube were 0.69 mm and 0.75 mm, respectively. The joint portion of the first outer layer and the joint portion of the second outer layer were at different positions in the length direction, and a smooth rigidity gradient could be achieved.

（実施例２）
実施例１と同様の方法で表２に示すカテーテルチューブを得た。得られたカテーテルチューブの柔軟な部分を先端側、最も硬い部分を手元側として、先端側にマーカーを取り付け、手元側にハブを取り付けることにより、マイクロカテーテルを作製した。得られたマイクロカテーテルは、耐キンク性、押込み性共に良好であった。

(Example 2)
A catheter tube shown in Table 2 was obtained in the same manner as in Example 1. A microcatheter was produced by attaching a marker to the distal side and a hub on the proximal side, with the flexible portion of the obtained catheter tube as the distal side and the hardest portion as the proximal side. The obtained microcatheter was good in both kink resistance and indentation.

（実施例３）
実施例２で得られたカテーテルチューブの先端側１０ｍｍにおいて、補強層の編組及び第１外層を研磨により除去して内層のみとし、マーカーを取り付けた後、更に実施例２の第１外層と同じ樹脂で内層のみの部分を被覆し、表３に示すカテーテルチューブを得た。手元側にハブを取り付けることにより、マイクロカテーテルを作製した。

(Example 3)
At the distal end side 10 mm of the catheter tube obtained in Example 2, the braid of the reinforcing layer and the first outer layer are removed by polishing to make only the inner layer, and after attaching the marker, the same resin as the first outer layer of Example 2 Then, only the inner layer was coated to obtain a catheter tube shown in Table 3. A microcatheter was prepared by attaching a hub to the proximal side.

  The obtained microcatheter was excellent in both kink resistance and indentation property, and in particular, the passage through a bent small diameter portion was very good.

（比較例１）
実施例１と同様の方法で編組チューブを作製した後、表４に示す外層を被覆して、１層の外層が被覆されたカテーテルチューブを得た。得られたカテーテルチューブの外径は０．７５ｍｍであった。外層の継目部で大きな硬度段差が発生し、耐キンク性が不良であった。

(Comparative Example 1)
A braided tube was prepared in the same manner as in Example 1, and then the outer layer shown in Table 4 was coated to obtain a catheter tube coated with one outer layer. The outer diameter of the obtained catheter tube was 0.75 mm. A large hardness step occurred at the joint of the outer layer, and kink resistance was poor.

（比較例２）
実施例１と同様の方法で表５に示す外層を被覆して、カテーテルチューブを得た。得られたカテーテルチューブは第１外層及び第２外層からなっているが、それぞれの接合部が長さ方向の同一場所になっていた。得られたカテーテルチューブの柔軟な部分を先端側、最も硬い部分を手元側として、先端側１０ｍｍにおいて補強層の編組及び第１外層を研磨により除去して内層のみとし、マーカーを取り付けた後、更に第１外層と同じ樹脂で内層のみの部分を被覆した。手元側にハブを取り付けることにより、マイクロカテーテルを作製した。

(Comparative Example 2)
The outer layer shown in Table 5 was coated in the same manner as in Example 1 to obtain a catheter tube. The obtained catheter tube was composed of a first outer layer and a second outer layer, but the respective joint portions were in the same place in the length direction. After the flexible part of the obtained catheter tube is the distal end side, the hardest part is the proximal side, the braid of the reinforcing layer and the first outer layer are removed by polishing at the distal end side 10 mm, and only the inner layer is attached. Only the inner layer was covered with the same resin as the first outer layer. A microcatheter was prepared by attaching a hub to the proximal side.

  When the obtained microcatheter was passed through a bent small diameter portion, the pushability was poor and kinks occurred at the joint.

It is sectional drawing of the catheter tube of the Example of this invention. It is a schematic sectional drawing of the catheter of the Example of this invention. It is a schematic sectional drawing of the catheter of another Example of this invention. It is a schematic sectional drawing of the microcatheter of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner layer 2 Reinforcement layer 3 1st outer layer 4 2nd outer layer 5 1st outer layer junction part 6 2nd outer layer junction part 7 Hand side outer layer 8 Inner layer and 1st outer layer only part 9 Inner layer, reinforcement layer, and 1st outer layer only part

Claims (7)

A catheter tube including an inner layer made of a fluororesin and an outer layer covering the inner layer,
The outer layer is
(A) a first outer layer comprising at least two resins having different hardnesses in the longitudinal direction of the catheter tube; and
(B) having at least two layers of a second outer layer covering the first outer layer (a), comprising at least two resins having different hardnesses in the longitudinal direction of the catheter tube;
The joint portion of two resins having different hardnesses in the first outer layer (a) and the joint portion of two resins having different hardnesses in the second outer layer (b) are in positions not parallel to each other in the longitudinal direction. Characteristic catheter tube. Of the two resins of the first outer layer (a), the hardness of the resin on the proximal end side is made higher than the hardness of the resin on the distal end side,
The hardness of the resin on the base end side of the two resins of the second outer layer (b) is made higher than the hardness of the resin on the front end side,
The catheter tube according to claim 1. A catheter tube comprising an inner layer and an outer layer covering the inner layer,
The outer layer is
(A) a first outer layer;
(B) a second outer layer covering the first outer layer,
And
The first outer layer (a)
A distal side resin part located on the distal side of the catheter tube, and a proximal side resin part bonded to the distal side resin part and having a hardness higher than that of the distal side resin part,
The second outer layer (b)
The resin part includes at least one resin part, and the resin part has a base end and a base end in order to reduce a variation in bending rigidity due to a difference in hardness between the tip side resin part and the base end side resin part. It is provided in a position that covers the joint with the side resin part,
A catheter tube characterized by.   A catheter comprising the catheter tube according to any one of claims 1 to 3 in at least one part.   A catheter characterized in that the catheter tube according to any one of claims 1 to 4 is included in a region from the distal end of the catheter to 500 mm in the longitudinal direction.   It has at least one of a portion consisting only of the inner layer and the first outer layer, or a portion consisting only of the inner layer, the reinforcing layer and the first outer layer in a region from the distal end of the catheter to 500 mm in the longitudinal direction. The catheter according to claim 4 or 5. The catheter according to any one of claims 4 to 6, wherein the catheter is a microcatheter.

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