Artificial blood vessel

Abstract

The artificial blood vessel alternately has, in the extending direction (D2) of the weft yarn (2): a first region (R1) where the warp yarn (1) and the weft yarn (2) are woven in a plain weave; a second region (R2) having a first part (R21) on the second region side where the warp yarn (1) crosses multiple weft yarns (2) and a second part (R22) on the second region side where the warp yarn (1) extends crossing one weft yarn (2); and a third region (R3) having a first part (R31) on the third region side where the warp yarn (1) crosses multiple weft yarns (2) and a second part (R32) on the third region side where the warp yarn (1) extends crossing one weft yarn (2). The first part (R21) on the second region side is adjacent to the second part (R32) on the third region side in the extending direction (D2) of the weft yarn (2), and the second part (R22) on the second region side is adjacent to the first part (R31) on the third region side in the extending direction (D2) of the weft yarn (2). The warp yarn (1) is composed of a multifilament yarn. By using this artificial blood vessel, it is possible to provide an artificial blood vessel having a woven structure with a plain weave region locally, which blocks the fiber gaps generated in the plain weave region and has improved leakage resistance.

Description

Technical Field

[0001] The present invention relates to an artificial blood vessel. Background Art

[0002] An artificial blood vessel is used, for example, to replace an unhealthy biological blood vessel. For an artificial blood vessel, in addition to biocompatibility and flexibility, it is also required to have less leakage of blood from the artificial blood vessel, that is, high leak resistance. In general polyester artificial blood vessels (cloth artificial blood vessels), many artificial blood vessels are woven with fibers in a plain weave (for example, refer to Patent Document 1), and a coating, a sealing layer, etc. are added to improve the leak resistance.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2012-139498 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] An artificial blood vessel having a plain weave structure is stable as a tissue, but there is a limit in the filling weft yarn, and in particular, the air holes at the four corners of the crossing part of the warp yarn and the weft yarn become large. Therefore, the high leak resistance required for the artificial blood vessel cannot be maintained only by the structure of the artificial blood vessel, and a coating is required to improve the leak resistance.

[0008] Accordingly, an object of the present invention is to provide an artificial blood vessel in which the leak resistance is improved by a three-dimensional structure of warp yarns in an artificial blood vessel having a woven structure locally having a plain weave region.

[0009] Means for Solving the Problems

[0010] The present invention is an artificial blood vessel having warp yarns and weft yarns, wherein the artificial blood vessel alternately has, in the extending direction of the weft yarns: a first region in which the warp yarns and the weft yarns are woven in a plain weave; a second region having a first part on the second region side where the warp yarns span multiple weft yarns and a second part on the second region side where the warp yarns extend spanning one weft yarn on one surface of the artificial blood vessel; and a third region having a first part on the third region side where the warp yarns span multiple weft yarns and a second part on the third region side where the warp yarns extend spanning one weft yarn on one surface of the artificial blood vessel, the first part on the second region side being adjacent to the second part on the third region side in the extending direction of the weft yarns, the second part on the second region side being adjacent to the first part on the third region side in the extending direction of the weft yarns, and the warp yarns being composed of multifilament yarns.

[0011] Advantages of the Invention

[0012] According to the artificial blood vessel of the present invention, in the artificial blood vessel having a woven structure partially having a plain weave region, the blood leakage resistance can be improved by the three-dimensional structure of the warp yarn. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram of the fabric structure of an artificial blood vessel according to one embodiment of the present invention.

[0014] Figure 2 Is has Figure 1 The SEM photograph of the outer surface of the artificial blood vessel with a braided structure is shown.

[0015] Figure 3 This is a diagram of the fabric structure of an artificial blood vessel according to another embodiment of the present invention.

[0016] Figure 4 This is a diagram of the fabric structure of an artificial blood vessel according to another embodiment of the present invention.

[0017] Figure 5 This is a diagram of the fabric structure of an artificial blood vessel according to another embodiment of the present invention. DETAILED DESCRIPTION

[0018] Hereinafter, an artificial blood vessel according to an embodiment of the present invention will be described with reference to the drawings. It should be noted that the embodiment described below is merely an example, and the artificial blood vessel of the present invention is not limited to the following embodiment.

[0019] Figure 1 FIG. 1 is a fabric structure diagram of an artificial blood vessel according to an embodiment of the present invention. Figure 1 , a portion of the outer surface of the artificial blood vessel (the area with 12 warp yarns and 12 weft yarns) is shown. Figure 1 In the figure, the part of the warp yarn exposed to the outer surface of the artificial blood vessel is shown in black, and the part of the weft yarn exposed to the outer surface of the artificial blood vessel is shown in white. Figure 2 Is has Figure 1 The SEM photograph of the outer surface of the artificial blood vessel with a braided structure is shown.

[0020] The artificial blood vessel is used, for example, to replace an unhealthy biological blood vessel or bypass a biological blood vessel. In this embodiment, the artificial blood vessel is formed by a woven structure of fibers. Figure 1 As shown, the artificial blood vessel of this embodiment has warp yarns 1a to 11 (hereinafter collectively referred to as warp yarns 1) and weft yarns 2a to 21 (hereinafter collectively referred to as weft yarns 2), and has a woven structure in which the warp yarns 1 and the weft yarns 2 are interlaced. Figure 1 In the embodiment, the warp yarn 1 extends in the vertical direction, and the extending direction of the warp yarn 1 is referred to as D1. Figure 1In this case, the weft yarn 2 extends in the left - right direction, and the extending direction of the weft yarn 2 is referred to as D2. Although not shown in the figure, in the artificial blood vessel, the warp yarn 1 is woven along the axial direction of the artificial blood vessel, and the weft yarn 2 is woven along the circumferential direction of the artificial blood vessel. It should be noted that there is no particular limitation on the loom used for manufacturing the artificial blood vessel. There is no particular limitation on the size of the artificial blood vessel of the present embodiment. For example, the artificial blood vessel can be a large - caliber (for thoracic and abdominal large arteries) artificial blood vessel with an inner diameter of 10 mm or more, or a medium - caliber (for arteries in the lower limbs, neck, and axillary region) artificial blood vessel with an inner diameter of 6 mm, 8 mm, etc., that is, an inner diameter of 6 mm or more and less than 10 mm, or a small - caliber artificial blood vessel with an inner diameter of less than 6 mm. There is no particular limitation on the axial length of the artificial blood vessel, and it can be appropriately changed according to the use.

[0021] In the present embodiment, as Figure 1 shown, the artificial blood vessel has a first region R1 in which the warp yarn 1 and the weft yarn 2 are woven in a plain weave. In addition, the artificial blood vessel has a second region R2. The second region R2 has a first part R21 on the second - region side on one surface of the artificial blood vessel (in the present embodiment, it is the outer surface of the artificial blood vessel) where the warp yarn 1 crosses multiple weft yarns 2, and a second part R22 on the second - region side where the warp yarn extends across 1 weft yarn. Moreover, the artificial blood vessel has a third region R3. The third region R3 has a first part R31 on the third - region side on one surface of the artificial blood vessel (in the present embodiment, it is the outer surface of the artificial blood vessel) where the warp yarn 1 crosses multiple weft yarns 2, and a second part R32 on the third - region side where the warp yarn 1 extends across 1 weft yarn 2. As Figure 1 shown, the first region R1, the second region R2, and the third region R3 are alternately formed in the extending direction D2 of the weft yarn 2. That is, the first region R1, the second region R2, and the third region R3 are arranged in sequence and repeatedly in the extending direction D2 of the weft yarn 2. The first part R21 on the second - region side is adjacent to the second part R32 on the third - region side in the extending direction D2 of the weft yarn 2, and the second part R22 on the second - region side is adjacent to the first part R31 on the third - region side in the extending direction D2 of the weft yarn 2. In addition, as Figure 2 shown, the warp yarn 1 is composed of multifilament yarn. By having the above - described structure, the artificial blood vessel of the present embodiment, as will be described later, the warp yarn 1 composed of multifilament yarn that extends without being restricted and relatively long in the first part R21 on the second - region side or the first part R31 on the third - region side expands in the first region R1 woven in a plain weave (and in the direction perpendicular to one surface of the artificial blood vessel. Figure 1 and Figure 2 the direction near the front of the paper surface in Figure 2)。Due to the three-dimensional structure of the warp yarn 1, when blood oozes out from the fiber gaps generated in the first region R1 woven in a plain weave, blood leakage can be inhibited, and the blood is retained within the three-dimensional structure. By coagulating the blood while it is being retained, the blood leakage resistance can be improved. Hereinafter, the structures of the respective parts of the artificial blood vessel and the weaving structure will be described.

[0022] The warp yarn 1 is a fiber that extends in one direction among the fibers constituting the artificial blood vessel. In the present embodiment, the warp yarn 1 is a fiber that extends in the axial direction of the artificial blood vessel. The warp yarn 1 is made of a material that can be applied to a cloth artificial blood vessel formed by a fiber weaving structure. The material of the warp yarn 1 is not particularly limited as long as it can be applied to a cloth artificial blood vessel. For example, the material of the warp yarn 1 can be set as polyester, polytetrafluoroethylene, polyamide, etc. In addition, a composite material composed of two or more materials that can be applied and have different properties such as melting point and elongation rate can also be used. For example, polyethylene terephthalate (PET) and polytrimethylene terephthalate (PTT) are compounded at the spinning stage and can be set as a synthetic fiber that forms a single long fiber with a spiral curl. For example, when a composite material composed of two materials with different melting points and elongation rates and having a spiral curl is used as the material of the warp yarn 1, the three-dimensional structure formed by the warp yarn 1 described later is likely to expand in the extension direction D2 of the weft yarn 2, the performance of retaining blood is further increased, and the blood leakage resistance can be improved.

[0023] In the present embodiment, each of the warp yarns 1 is composed of multifilament yarns (refer to Figure 2)。The fineness of the warp yarn 1 only needs to be such that the single fibers of the warp yarn 1 extend toward the first region R1 and can block the fiber gaps, and there is no particular limitation. Regarding the fineness of the warp yarn 1, for example, the single yarn fineness of the warp yarn 1 can be set to 0.25 to 2.50 dtex, preferably 0.50 to 2.00 dtex, and the total fineness of the warp yarn 1 can be set to 2 to 2500 dtex, preferably 6 to 1600 dtex, more preferably 10 to 540 dtex, and further preferably 30 to 200 dtex. By setting the single yarn fineness and the total fineness of the warp yarn 1 within the above ranges, the warp yarn 1 in the second region R2 and the third region R3 can extend well toward the first region R1. Therefore, when blood oozes out from the gaps in the first region R1 through the warp yarn 1 in the second region R2 and the third region R3, blood leakage can be suppressed, and the blood is held by the three-dimensional structure of the warp yarn 1. By coagulating the blood in the held state, the blood leakage resistance can be improved. It should be noted that the "single yarn fineness" is the fineness of an average of one single fiber constituting the warp yarn 1, and the "total fineness" is the product of the single yarn fineness and the number of single fibers constituting the warp yarn 1. It should be noted that the number of single fiber yarns constituting one warp yarn (hereinafter referred to as the number of single fibers) is not particularly limited. However, for example, as described later, when the total number of single fibers of the warp yarn 1 is 1.5 times or more the average number of single fibers of one weft yarn 2 and the number of warp yarns of the warp yarn 1 that straddle multiple weft yarns 2 in the second region R2 is 1, the average number of single fibers of the warp yarn 1 can be set to 8 to 1000, preferably 12 to 800, more preferably 20 to 270, and further preferably 60 to 100. It should be noted that, as described later, when the average number of single fibers of the warp yarn 1 is 0.8 to 1.2 times the average number of single fibers of one weft yarn 1 and the number of warp yarns of the warp yarn 1 that straddle multiple weft yarns 2 in the second region R2 is 2 or more, the average number of single fibers of the warp yarn 1 can be set to 4 to 500, preferably 6 to 400, more preferably 10 to 135, and further preferably 30 to 50.

[0024] The weft yarn 2 is a fiber that extends in a direction intersecting with the warp yarn 1 among the fibers constituting the artificial blood vessel. In the present embodiment, the weft yarn 2 is a fiber that extends in the circumferential direction of the artificial blood vessel. The weft yarn 2 is made of a material that can be applied to a cloth artificial blood vessel formed by a fiber weaving structure. The material of the weft yarn 2 only needs to be a material that can be applied to a cloth artificial blood vessel, and there is no particular limitation. For example, the material of the weft yarn 2 can be set to polyester, polytetrafluoroethylene, polyamide, etc.

[0025] Each of the weft yarns 2 can be a monofilament yarn or a multifilament yarn. However, in the present embodiment, as Figure 2As shown, the weft yarn 2 is composed of multifilament yarn. The fineness of the weft yarn 2 is not particularly limited. However, for example, when the weft yarn 2 is a monofilament yarn, the single yarn fineness of the weft yarn can be set to 15 to 100 dtex, preferably 20 to 75 dtex. In addition, when each of the weft yarns 2 is composed of multifilament yarn, for example, the single yarn fineness of the weft yarn 2 can be set to 0.25 to 2.50 dtex, preferably 0.50 to 2.00 dtex, and the total fineness of the weft yarn 2 can be set to 1 to 1250 dtex, preferably 3 to 800 dtex, more preferably 5 to 270 dtex, and further preferably 15 to 100 dtex. It should be noted that the "single yarn fineness" is the fineness of an average of one single fiber (monofilament or multifilament) constituting the weft yarn 2, and the "total fineness" is the product of the single yarn fineness and the number of single fibers constituting the weft yarn 2. It should be noted that when the weft yarn 2 is composed of multifilament yarn, the number of single fiber yarns constituting one weft yarn can be set to 4 to 500, preferably 6 to 400, more preferably 10 to 135, and further preferably 30 to 50.

[0026] The first region R1 is a portion where the warp yarn 1 and the weft yarn 2 are plain woven. In Figure 1 it, the first region R1 is a region where the warp yarns 1a, 1b, 1g, 1h and the weft yarn 2 (weft yarns 2a to 2l) are interlaced. The first region R1 improves the strength of the artificial blood vessel, especially the tensile strength (in the axial direction of the artificial blood vessel). The first region R1 extends along the extension direction D1 of the warp yarn 1 and extends in the axial direction of the artificial blood vessel. In addition, a plurality of first regions R1 are arranged at a prescribed interval and separated from each other in the extension direction D2 of the weft yarn 2. In the extension direction D2 of the weft yarn 2, a second region R2 and a third region R3 are arranged between one first region R1 and another first region R1.

[0027] In the present embodiment, in the first region R1, as Figure 1As shown, two warp yarns 1a, 1b (1g, 1h) and multiple weft yarns 2a to 2l (and weft yarns not shown) are plain woven. The number of warp yarns of the warp yarn 1 provided in one first region R1 can be set to 2 to 4, preferably 2 to 3, and more preferably 2. It should be noted that when referring to the "number of warp yarns" in this specification, it does not refer to the number of single fibers constituting the multifilament yarn, but rather to the number of warp yarns 1 formed by gathering multiple single fiber yarns together as one warp yarn, and how many such gathered warp yarns 1 there are. By setting the number of warp yarns of the warp yarn 1 within the above range, the range of the first region R1 that is not covered by the warp yarn 1 of the first part R21 on the second region side and the warp yarn 1 of the first part R31 on the third region side can be reduced. Therefore, the first region R1 of the plain weave is easily three-dimensionally covered by the warp yarn 1 of the first part R21 on the second region side and the warp yarn 1 of the first part R31 on the third region side. When blood oozes from the first region R1, the three-dimensional structure of the warp yarn 1 of the first part R21 on the second region side and the warp yarn 1 of the first part R31 on the third region side holds the blood, and the blood coagulates in the held state, so the blood leakage amount from the artificial blood vessel can be reduced. In addition, in the artificial blood vessel, the ratio (number of warp yarns in the first region R1 / total number of warp yarns) of the number of warp yarns of the warp yarn 1 in the first region R1 to the total number of warp yarns of the warp yarn 1 arranged in the extending direction D2 of the weft yarn 2 in the first region R1 to the third region R3 is not particularly limited, but can be set to 0.2 to 0.4 (1 / 3 in this embodiment), for example. By making the number of warp yarns of the warp yarn 1 in the first region R1 and the ratio of the number of warp yarns within the above range, the blood leakage amount from the artificial blood vessel can be reduced while improving the strength of the artificial blood vessel.

[0028] The second region R2 has a first part R21 on the second region side where the warp yarn 1 spans multiple weft yarns 2 and a second part R22 on the second region side where the warp yarn 1 extends across one weft yarn 2. As Figure 1 shown, the first part R21 on the second region side and the second part R22 on the second region side are alternately arranged in the extending direction D1 of the warp yarn 1. By the second region R2 having the first part R21 on the second region side and the second part R22 on the second region side, the artificial blood vessel can be made softer compared to when the entire artificial blood vessel has a plain weave structure. The number of warp yarns of the warp yarn 1 provided in the second region R2 can be set to, for example, 1 to 4, preferably 2 to 3, and more preferably 2.

[0029] The first part R21 on the second region side is a part woven in such a manner that the warp yarns 1 cross over multiple weft yarns 2. In the present embodiment, the warp yarns 1d, 1j, etc. cross over multiple weft yarns 2. By having the warp yarns 1 cross over multiple weft yarns 2 in the first part R21 on the second region side, the artificial blood vessel becomes softer in this part compared to a plain weave structure. In addition, the warp yarns 1 of the first part R21 on the second region side are composed of multifilament yarns, and both ends of the first part R21 on the second region side in the extending direction D1 of the warp yarns 1 are in a state of being constrained by the weft yarns 2 of the second part R22 on the second region side. Thus, as Figure 2 shown, a three-dimensional structure is formed in which the multifilament yarns with both ends constrained expand in the extending direction D2 of the weft yarns 2 (it should be noted that this three-dimensional structure also expands in the Figure 2 direction closer to the front of the paper surface in

[0030] In the first part R21 on the second region side (from when the warp yarns 1 come out from one surface of the artificial blood vessel to the other surface (the surface shown in Figure 1 ), the number of weft yarns 2 that the warp yarns 1 cross over is not particularly limited, but can be set to, for example, 2 to 5, preferably 3 to 4, and more preferably 3 ( Figure 1 shown state). By setting the number of weft yarns 2 that the warp yarns 1 cross over in the first part R21 on the second region side within the above range, it is easy for the multifilament yarns of the warp yarns 1 to expand in the extending direction D2 of the weft yarns 2, and the artificial blood vessel can be maintained at a specified strength.

[0031] For the first part R21 on the second region side, it is sufficient that the warp yarns 1 have a portion that crosses multiple weft yarns 2, and the number of warp yarns 1 constituting the first part R21 on the second region side is not particularly limited. In the present embodiment, the first part R21 on the second region side has a plurality (2) of warp yarns 1c, 1d (or warp yarns 1i, 1j). It should be noted that the second region R2 may also have at least one warp yarn 1 that extends across (only) one weft yarn 2 and at least one warp yarn 1 that crosses multiple weft yarns 2. In the present embodiment, similar to the first region R1 having a plain weave structure, the second region R2 includes a warp yarn 1c (warp yarn 1i) that extends from one side of the artificial blood vessel to the other side after crossing only one weft yarn 2 and a warp yarn 1d (warp yarn 1j) that extends from one side of the artificial blood vessel to the other side after crossing multiple weft yarns 2.

[0032] The second part R22 on the second region side is a portion woven in such a way that the warp yarn 1 crosses only one weft yarn 2 (from the warp yarn 1 coming out from the other side of the artificial blood vessel to one side (the side shown in Figure 1 until it goes to the other side without crossing multiple weft yarns 2). The second part R22 on the second region side is set to have a length similar to that of the first part R21 on the second region side in the extension direction D1 of the warp yarn 1. That is, the number of weft yarns of the weft yarn 2 in the first part R21 on the second region side (3 in Figure 1 ) is equal to the number of weft yarns of the weft yarn 2 in the second part R22 on the second region side (3 in Figure 1 ).

[0033] The third region R3 has a first part R31 on the third region side where the warp yarn 1 crosses multiple weft yarns 2 and a second part R32 on the third region side where the warp yarn 1 extends across one weft yarn 2. As Figure 1 shown, the first part R31 on the third region side and the second part R32 on the third region side are alternately arranged in the extension direction D1 of the warp yarn 1. By having the first part R31 on the third region side and the second part R32 on the third region side in the third region R3, compared with the artificial blood vessel having an all-plain weave structure, the artificial blood vessel can be made softer. The number of warp yarns of the warp yarn 1 provided in the third region R3 can be set to, for example, 1 to 4, preferably 2 to 3, and more preferably 2.

[0034] The first part R31 on the third region side is a part woven in such a way that the warp yarns 1 cross over multiple weft yarns 2. In the present embodiment, warp yarns 1e, 1k, etc. cross over multiple weft yarns 2. By having the warp yarns 1 cross over multiple weft yarns 2 in the first part R31 on the third region side, the artificial blood vessel becomes softer in this part compared to a plain weave structure. In addition, the warp yarns 1 of the first part R31 on the third region side are composed of multifilament yarns, and both ends of the first part R31 on the third region side in the extending direction D1 of the warp yarns 1 are in a state of being constrained by the weft yarns 2 of the second part R32 on the third region side. Thus, as Figure 2 shown, a three-dimensional structure is formed in which the multifilament yarns with both ends constrained expand in the extending direction D2 of the weft yarns 2. It should be noted that this three-dimensional structure also expands in the direction towards the front of the paper surface in Figure 2 . Therefore, the first region R1 with a plain weave structure adjacent to the first part R31 on the third region side in the extending direction D2 of the weft yarns 2 is partially covered by the multifilament yarns of the expanded first part R31 on the third region side. Due to this three-dimensional structure of the warp yarns 1, when blood oozes out from the fiber gaps generated in the first region R1 woven with a plain weave, the oozed blood is retained in the gaps between the single fibers of the three-dimensional structure composed of multifilaments. Thus, by blood coagulation in the retained state, the leak resistance can be improved. In addition, in the present embodiment, the second part R22 on the second region side adjacent to the first part R31 on the third region side in the extending direction D2 of the weft yarns 2 is also similarly partially covered by the multifilament yarns of the expanded first part R31 on the third region side. Thus, regarding the gaps generated in the second part R22 on the second region side, they are also covered by the multifilament yarns of the first part R31 on the third region side, and the blood in the artificial blood vessel is not likely to leak to the outside.

[0035] In the first part R31 on the third region side (from when the warp yarns 1 come out from one surface of the artificial blood vessel to the other surface (the surface shown in Figure 1 ), there is no particular limitation on the number of weft yarns 2 that the warp yarns 1 cross over. For example, it can be set to 2 to 5, preferably 3 to 4, and more preferably 3 ([[]] Figure 1 shown state). By setting the number of weft yarns 2 that the warp yarns 1 cross over in the first part R31 on the third region side within the above range, it is easy for the multifilament yarns of the warp yarns 1 to expand in the extending direction D2 of the weft yarns 2, and the artificial blood vessel can be maintained at a specified strength.

[0036] For the first part R31 on the third region side, it is sufficient that the warp yarn 1 has a portion that crosses multiple weft yarns 2, and the number of warp yarns 1 constituting the first part R31 on the third region side is not particularly limited. In the present embodiment, the first part R31 on the third region side has a plurality (two) of warp yarns 1e, 1f (or warp yarns 1k, 1l). It should be noted that the third region R3 may also have at least one warp yarn 1 that extends across only one weft yarn 2 and at least one warp yarn 1 that crosses multiple weft yarns 2. In the present embodiment, similar to the first region R1 having a plain weave structure, the third region R3 includes a warp yarn 1f (warp yarn 1l) that extends from one surface of the artificial blood vessel to the other surface after crossing only one weft yarn 2 and a warp yarn 1e (warp yarn 1k) that extends from one surface of the artificial blood vessel to the other surface after crossing multiple weft yarns 2.

[0037] The second part R32 on the third region side is a portion woven in such a way that the warp yarn 1 crosses only one weft yarn 2 (from the warp yarn 1 coming out from the other surface of the artificial blood vessel to one surface (the surface shown in Figure 1 until it goes to the other surface without crossing multiple weft yarns 2). The second part R32 on the third region side is set to have a length similar to that of the first part R31 on the third region side in the extension direction D1 of the warp yarn 1. That is, the number of weft yarns of the weft yarn 2 in the first part R31 on the third region side (in Figure 1 is three) is the same as the number of weft yarns of the weft yarn 2 in the second part R32 on the third region side (in Figure 1 is three).

[0038] As described above, the artificial blood vessel alternately has a first region R1 woven in a plain weave with warp yarns 1 and weft yarns 2 in the extending direction D2 of the weft yarn 2, a second region R2 having a first part R21 on the second region side and a second part R22 on the second region side, and a third region R3 having a first part R31 on the third region side and a second part R32 on the third region side. The first part R21 on the second region side is adjacent to the second part R32 on the third region side in the extending direction D2 of the weft yarn 2, and the second part R22 on the second region side is adjacent to the first part R31 on the third region side in the extending direction D2 of the weft yarn 2. The warp yarn 1 is composed of multifilament yarns. Thus, the multifilament yarns of the warp yarn 1 in the first part R21 on the second region side expand in the extending direction D2 of the weft yarn 2, locally covering the first region R1 adjacent to the first part R21 on the second region side, and filling the gaps (air holes) formed at the four corners of the crossing portion of the warp yarn 1 and the weft yarn 2 formed in the first region R1. Moreover, the multifilament yarns of the warp yarn 1 in the first part R31 on the third region side expand in the extending direction D2 of the weft yarn 2, locally covering the first region R1 adjacent to the first part R31 on the third region side, and the gaps (air holes) formed at the four corners of the crossing portion of the warp yarn 1 and the weft yarn 2 formed in the first region R1 are covered by the multifilament yarns of the first part R21 on the second region side and the first part R31 on the third region side. Therefore, when blood oozes out from the fiber gaps generated in the first region R1 woven in a plain weave, due to the three-dimensional structure of the warp yarn 1, the oozed blood is retained in the gaps between the single fibers of the three-dimensional structure composed of multifilaments, and the blood can coagulate without flowing out. Thus, the leak resistance can be improved. In addition, in the present embodiment, the multifilament yarns of the warp yarn 1 in the first part R21 on the second region side locally cover the second part R32 on the third region side adjacent to the first part R21 on the second region side, covering the gaps (air holes) formed at the crossing portion of the warp yarn 1 and the weft yarn 2 formed in the second part R32 on the third region side. Moreover, the multifilament yarns of the warp yarn 1 in the first part R31 on the third region side locally cover the second part R22 on the second region side adjacent to the first part R31 on the third region side, covering the gaps (air holes) formed at the crossing portion of the warp yarn 1 and the weft yarn 2 formed in the second part R22 on the second region side. Therefore, the blood in the artificial blood vessel is not likely to leak to the outside from the gaps in the second part R32 on the third region side and the second part R22 on the second region side, and the leak resistance of the artificial blood vessel is improved.

[0039] Moreover, in the present embodiment, the first region R1 having a plain weave structure, the second region R2 and the third region R3 having a weave structure different from the plain weave structure are alternately formed in the extending direction D2 of the weft yarn 2. Therefore, while ensuring a predetermined strength of the artificial blood vessel by using the first region R1 provided at a predetermined interval in the extending direction D2 of the weft yarn 2, the predetermined flexibility required for the artificial blood vessel can be obtained by using the second region R2 and the third region R3. Therefore, according to the artificial blood vessel of the present embodiment, in addition to the improvement of the leak resistance, the strength and flexibility required for the artificial blood vessel can also be achieved simultaneously.

[0040] In addition, in the present embodiment, as Figure 1 shown, the first part R21 on the second region side and the first part R31 on the third region side are configured to continuously extend in a zigzag shape in the extending direction D1 of the warp yarn 1. In this case, the warp yarns 1 of the first part R21 on the second region side and the first part R31 on the third region side that expand in the extending direction D2 of the weft yarn 2 do not interfere with each other, and the expansion of the warp yarns 1 does not interrupt in the extending direction D1 of the warp yarn 1. Therefore, the absorbability of the three-dimensional structure to blood can be further improved.

[0041] When the first part R21 on the second region side and the first part R31 on the third region side of the warp yarn 1 are maximally expanded in the extending direction D2 of the weft yarn 2 (refer to Figure 2 Wa1 to Wa3 in), the average width is preferably larger than the average width when the warp yarn 1 in the first region R1 is maximally expanded in the extending direction D2 of the weft yarn 2 (refer to Wb1 to Wb3). In this case, the gaps of the first region R1, the second part R22 on the second region side, and the second part R32 on the third region side are covered by the warp yarns 1 of the first part R21 on the second region side and the first part R31 on the third region side in a relatively wide area. Therefore, it is easy to further retain the blood oozing from the gaps of the first region R1, the second part R22 on the second region side, and the second part R32 on the third region side, and the leak resistance can be further improved. It should be noted that the average width when the first part R21 on the second region side and the first part R31 on the third region side of the warp yarn 1 are maximally expanded in the extending direction D2 of the weft yarn 2 is not particularly limited, but can be set to, for example, 2.0 to 4.0 times the average width when the warp yarn 1 in the first region R1 is maximally expanded in the extending direction D2 of the weft yarn 2.

[0042] It should be noted that regarding "the average width when the first part R21 on the second region side and the first part R31 on the third region side of the warp yarn 1 are maximally expanded in the extending direction D2 of the weft yarn 2", for example, in a predetermined area (e.g., 1 mm × 1 mm) of the artificial blood vessel, the width of the part where the expansion of the warp yarns 1 of the first part R21 on the second region side and the first part R31 on the third region side becomes the largest (refer toFigure 2 Measure a prescribed number m (for example, 10 or more) of Wa1 to Wa3, and calculate their average value ((Wa1 + Wa2 + … + Wam) / m).

[0043] Alternatively, in the artificial blood vessel, the weft yarn 2 is composed of multifilament yarns. In the second region R2 and the third region R3, the total number of single fibers of the warp yarn 1 ( Figure 1 such as the warp yarns 1d, 1e, 1j, 1k) that straddle multiple weft yarns 2 is 1.5 times or more, preferably 1.5 to 3.0 times, the average number of single fibers of one weft yarn 2. Here, regarding "the total number of single fibers of the warp yarn 1 that straddle multiple weft yarns 2", in one second region R2 or one third region R3, when the number of warp yarns of the warp yarn 1 that straddle multiple weft yarns 2 is 1, it is the number of single fibers of that one warp yarn, and when the number of warp yarns of the warp yarn 1 that straddle multiple weft yarns 2 is multiple (for example, 2 or 3), it is the total number of single fibers of the multiple warp yarns 1 (the number obtained by multiplying the number of single fibers of one warp yarn 1 by the number of warp yarns, i.e., 2 or 3). By having the total number of single fibers of the warp yarn 1 that straddle multiple weft yarns 2 be more than the average number of single fibers of one weft yarn 2, the multifilament yarn of the warp yarn 1 is more likely to expand than the multifilament yarn of the weft yarn 2, and the leakage resistance can be further improved. That is, the warp yarn 1 with a total number of single fibers more than that of the weft yarn 2 is constrained by the weft yarn 2 that is thinner (with fewer single fibers) at both ends of the first part R21 on the second region side and the first part R31 on the third region side in the extension direction D1 of the warp yarn 1. Thus, by being constrained by the thin weft yarn 2 to apply a strong pressure to the warp yarn 1, the warp yarn 1 is more likely to expand in the extension direction D2 of the weft yarn 2. Moreover, when the total number of single fibers of the warp yarn 1 and the average number of single fibers of one weft yarn 2 are set at the above ratio, the number of single fibers of the weft yarn 2 relative to the single fibers of the warp yarn 1 becomes smaller, and it is easy to pack the weft yarn 2 in the extension direction D1 of the warp yarn 1 when knitting the artificial blood vessel. Therefore, by packing the weft yarn 2 in the extension direction D1 of the warp yarn 1, the gap (air hole) formed at the intersection of the warp yarn 1 and the weft yarn 2 can be reduced, and the amount of leaked blood itself can be decreased. Therefore, through the complementary effects of the reduction of the amount of leaked blood itself achieved by packing the weft yarn 2 and the absorbability of the leaked blood achieved by the three-dimensional structure of the warp yarn 1, the leakage resistance can be dramatically improved.

[0044] In the present embodiment, it is configured such that in each of the second region R2 and the third region R3, the number of warp yarns 1 spanning multiple weft yarns 2 is 1, and the number of single fibers per average 1 warp yarn 1 in the second region R2 and the third region R3 is 1.5 times or more, preferably 1.5 to 3 times, the number of single fibers per average 1 weft yarn. Specifically, the number of single fibers per average 1 weft yarn 2 is 4 to 500, and the number of single fibers per average 1 warp yarn 1 can be set to 8 to 1000. Thus, in each of the second region R2 and the third region R3, the multifilament yarn of the warp yarn 1 spanning multiple weft yarns 2 is bundled into 1, which is more than the number of single fibers of the weft yarn 2. It should be noted that as long as it is configured such that the total number of single fibers of the single fibers of the warp yarn 1 spanning multiple weft yarns 2 in the second region R2 and the third region R3 is 1.5 times or more the number of single fibers per average 1 weft yarn, the structures of the warp yarn 1 and the weft yarn 2 are not particularly limited to the above structures. For example, it may be that in the second region R2 and the third region R3, the number of warp yarns 1 spanning multiple weft yarns 2 is 2 or more, and the number of single fibers per average 1 warp yarn 1 is 0.8 to 1.2 times (preferably the same number of single fibers) the number of single fibers per average 1 weft yarn. Also in this case, since the number of warp yarns 1 spanning multiple weft yarns 2 is 2 or more, in the second region R2 and the third region R3, the total number of single fibers of the single fibers of the warp yarn 1 spanning multiple weft yarns 2 is more than the number of single fibers per average 1 weft yarn. Therefore, the same effect as the above effect can be obtained.

[0045] In addition, in the present embodiment, as Figure 1As shown, the second region R2 has at least one warp yarn 1 (warp yarns 1c, 1i) extending across (only) one weft yarn 2 and at least one warp yarn 1 (warp yarns 1d, 1j) extending across multiple weft yarns 2. At both ends of the first part R21 on the second region side in the extending direction D1 of the warp yarn 1, the multifilament yarns of the multiple warp yarns 1 constituting the second region R2 are bundled by the weft yarns 2 crossing the multiple warp yarns 1 (warp yarns 1c, 1d or warp yarns 1i, 1j) of the second region R2. For example, both ends of the warp yarn 1c and the warp yarn 1d crossing the weft yarns 2g, 2h, 2i are bundled by the weft yarns 2f and 2j. Moreover, the third region R3 has at least one warp yarn 1 (warp yarns 1f, 1l) extending across (only) one weft yarn 2 and at least one warp yarn (warp yarns 1e, 1k) extending across multiple weft yarns 2. At both ends of the first part R31 on the third region side in the extending direction D1 of the warp yarn 1, the multifilament yarns of the multiple warp yarns 1 constituting the third region R3 are bundled by the weft yarns 2 crossing the multiple warp yarns 1 (warp yarns 1d, 1f or warp yarns 1k, 1l) of the third region R3. For example, both ends of the warp yarn 1e crossing the weft yarns 2d, 2e, 2f and the warp yarn 1f are bundled by the weft yarns 2c and 2g. In the above cases, in the second region R2 and the third region R3, different from the first region R1 having a plain weave structure, multiple (two in Figure 1 this case) warp yarns 1 are concentrated and bundled (constrained) on one surface of the artificial blood vessel. Thus, the expansion of the central parts of the first part R21 on the second region side and the first part R31 on the third region side in the extending direction D2 of the weft yarn 2 becomes larger, and the amount of blood that the three-dimensional structure of the warp yarn 1 can absorb can be increased. Therefore, the leak resistance can be further improved.

[0046] In addition, in the present embodiment, in the second region R2 and the third region R3, the number of single fibers of the warp yarns 1 (e.g., 1d, 1e, 1j, 1k) extending across multiple weft yarns 2 is more (e.g., 1.5 to 3 times) than the average number of single fibers of one weft yarn 2, and the number of single fibers of the warp yarns 1 (e.g., 1c, 1f, 1i, 1l) extending across only one weft yarn 2 is also more (e.g., 1.5 to 3 times) than the average number of single fibers of one weft yarn 2. Two warp yarns 1 with a larger number of single fibers than the average number of single fibers of one weft yarn 2 are bundled by one weft yarn 2 with a smaller number of single fibers. Thus, the reaction force exerted on one weft yarn 2 from the warp yarns 1 is larger than the case of bundling one warp yarn and the case of bundling warp yarns with a smaller average number of single fibers. Therefore, for example, when the artificial blood vessel is cut along the extending direction D2 of the weft yarn, when the artificial blood vessel is touched by a doctor or the like, the weft yarn 2 is not easily loosened from the cut part. In addition, as described above, in the second region R2 and the third region R3, the warp yarns 1 expand in the extending direction D2 of the weft yarn 2 and cover the surface of the weft yarn 2. Thus, the weft yarn 2 is not easily exposed on the surface of the artificial blood vessel, and when the artificial blood vessel is touched by a doctor or the like, the chance of touching the weft yarn 2 is reduced, so the loosening of the weft yarn 2 from the cut part of the artificial blood vessel can be suppressed.

[0047] It should be noted that the second region R2 and the third region R3 are not limited to the Figure 2 arrangement shown, and may also be configured as in the Figures 3 to 5 deformation example shown. In Figure 3 , Figure 2 the warp threads 1e (warp thread 1k) and 1f (warp thread 1l) in the first part R31 on the third region side are opposite (left and right opposite) in the extension direction D2 of the weft thread 2. In Figure 4 , Figure 2 the warp threads 1c (warp thread 1i) and 1d (warp thread 1j) in the first part R21 on the second region side are opposite (left and right opposite) in the extension direction D2 of the weft thread 2. In Figure 5 , Figure 2 the warp threads 1c (warp thread 1i) and 1d (warp thread 1j) in the first part R21 on the second region side are opposite (left and right opposite) in the extension direction D2 of the weft thread 2, and the warp threads 1e (warp thread 1k) and 1f (warp thread 1l) in the first part R31 on the third region side are opposite (left and right opposite) in the extension direction D2 of the weft thread 2. Thus, as long as the artificial blood vessel satisfies the features of the claims and has the technical idea of the present invention, it is not limited to the structure shown in the figure, and can also be configured as a structure other than the one shown in the figure.

[0048] Reference Signs Explanation

[0049] 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l Warp Threads

[0050] 2, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2l Weft Threads

[0051] D1 Extension Direction of Warp Threads

[0052] D2 Extension Direction of Weft Threads

[0053] R1 First Region

[0054] R2 Second Region

[0055] R21 First Part on Second Region Side

[0056] R22 Second Part on Second Region Side

[0057] R3 Third Region

[0058] R31 First Part on Third Region Side

[0059] R32 Second Part on Third Region Side

Claims

1. An artificial blood vessel having warp yarns and weft yarns, wherein, the artificial blood vessel alternately has, in the extending direction of the weft yarns: a first region where the warp yarns and the weft yarns are woven in a plain weave; a second region having, on one surface of the artificial blood vessel, a first part on the second region side where the warp yarns span multiple weft yarns and a second part on the second region side where the warp yarns extend spanning 1 weft yarn; and a third region having, on one surface of the artificial blood vessel, a first part on the third region side where the warp yarns span multiple weft yarns and a second part on the third region side where the warp yarns extend spanning 1 weft yarn, the first part on the second region side is adjacent to the second part on the third region side in the extending direction of the weft yarns, and the second part on the second region side is adjacent to the first part on the third region side in the extending direction of the weft yarns, the warp yarns are composed of multifilament yarns.

2. The artificial blood vessel according to claim 1, wherein, the first part on the second region side and the first part on the third region side are configured to continuously extend in a zigzag shape in the extending direction of the warp yarns.

3. The artificial blood vessel according to claim 1 or 2, wherein, the second region has at least 1 warp yarn extending spanning 1 weft yarn and at least 1 warp yarn spanning multiple weft yarns, at both ends of the first part on the second region side in the extending direction of the warp yarns, the multifilament yarns of the multiple warp yarns constituting the second region are bundled by the weft yarns spanning the multiple warp yarns of the second region, the third region has at least 1 warp yarn extending spanning 1 weft yarn and at least 1 warp yarn spanning multiple weft yarns, at both ends of the first part on the third region side in the extending direction of the warp yarns, the multifilament yarns of the multiple warp yarns constituting the third region are bundled by the weft yarns spanning the multiple warp yarns of the third region.

4. The artificial blood vessel according to claim 1, wherein, the weft yarns are composed of multifilament yarns, in the second region and the third region, the total number of single fibers of the warp yarns spanning multiple weft yarns is 1.5 times or more the average number of single fibers of 1 weft yarn.

5. The artificial blood vessel according to claim 4, wherein, in the second region and the third region, the number of warp yarns spanning multiple weft yarns is 1, the average number of single fibers of 1 weft yarn is 4 to 500, and the average number of single fibers of 1 warp yarn is 8 to 1000.

6. The artificial blood vessel according to claim 4, wherein, in the second region and the third region, the number of warp yarns spanning multiple weft yarns is 2 or more, and the average number of single fibers of 1 warp yarn is 0.8 to 1.2 times the average number of single fibers of 1 weft yarn.

7. The artificial blood vessel according to claim 1, wherein, the average width when the first part on the second region side and the first part on the third region side of the warp yarns are maximally expanded in the extending direction of the weft yarns is larger than the average width when the warp yarns in the first region are maximally expanded in the extending direction of the weft yarns.

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