JP4149461B2 - Catheter balloon and balloon catheter and vasodilator catheter - Google Patents

Description

  The present invention relates to a balloon for a catheter and a balloon catheter. In particular, the present invention relates to a balloon for expanding a narrowed portion of a tubular organ such as a blood vessel and a balloon catheter or a vasodilator catheter.

In recent years, as a treatment for myocardial infarction or angina pectoris, a method of expanding a coronary artery lesion (stenosis) by a catheter with a balloon (a balloon catheter for vasodilation) has been generally performed.
A general structure of a vascular dilatation balloon catheter includes a main body shaft, an dilatation balloon attached near the tip of the main body shaft, and a hub attached to the main body shaft base.

Polyolefin, PET, polyamide, etc. are used as the material for the balloon for expansion, and each has different properties.
Low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), etc. are used as the polyolefin, and generally heat fusion is applied to the shaft. Although it is flexible, the pressure resistance is relatively weak, and it has the property that the change in the balloon diameter is large (the compliance is large) with respect to the change in the pressure for expanding the balloon.

Polyethylene terephthalate (hereinafter referred to as PET) generally has high strength, high pressure resistance, and low compliance. For this reason, the balloon itself is hard and tends to have low trackability (the property that the balloon can follow the meandering blood vessel). If the balloon thickness is reduced to avoid this, the flexibility is improved, but the pressure resistance is lowered and pinholes are more likely to occur.
Nylon or polyamide balloons have almost the same properties as polyolefin and PET. However, if the wall thickness is reduced, it will be disadvantageous in terms of pressure resistance and pinholes. It is not satisfactory in terms.

  In order to compensate for the drawbacks of these balloon materials, particularly when PET is used as the material, a balloon made of PET as a base polymer and multilayered with polyethylene or the like is disclosed in JP-A-3-205064 (Patent Document 1) or JP-T-6. -507101 (Patent Document 2). These are for the purpose of improving heat-fusibility to the shaft when PET is used as a balloon material, or improving pinhole resistance, and do not consider any improvement on flexibility.

Japanese Patent Laid-Open No. 3-205064 JP-T 6-507101

In the balloon disclosed in the above publication, when trying to obtain a balloon with high strength (pressure resistance), the balloon itself becomes hard and the trackability becomes inferior, and when trying to obtain a flexible balloon and making it thin, Inadequate, and there was a problem with respect to pinhole resistance.
An object of the present invention is to provide a catheter balloon and a balloon catheter having sufficient strength (pressure resistance), excellent trackability, and flexibility.

What achieves the above object is as follows.
What solves the said subject is a balloon for catheters provided with a cylindrical part and a catheter junction part, Comprising: This balloon is a base material layer which consists of a thermoplastic resin which can be extended , At least one surface of this base material layer A balloon for a catheter having a multilayer structure having a coating layer made of a thermoplastic resin that is more flexible and stretchable than the resin that forms the base material layer, and the resin that forms the base material layer and the coating layer. The difference in tensile breaking strength from the resin to be formed is 30% or less, and the balloon for catheter is a biaxially stretched balloon in which both the base material layer and the coating layer are biaxially stretched, and the tube the thickness of the Jo portion Ri der less 25 [mu] m, and mosquitoes, characterized in that the biaxially oriented balloon to more than 10% of the stress due to internal pressure in the state of applying the maximum pressure is related to the coating layer It is an ether balloon.

And, it is preferable that 20% or more, more preferably 30% or more, of the stress due to the internal pressure in the state where the maximum internal pressure is applied in the balloon is applied to the coating layer. The forming resin that forms the coating layer is preferably a polymer of the same series as the forming resin that forms the base layer. For example, the forming resin that forms the base material layer is polyethylene terephthalate, and the forming resin that forms the coating layer is, for example, a polyester elastomer. For example, the forming resin that forms the base material layer is polyamide, and the forming resin that forms the coating layer is a polyamide elastomer.

And the said base material layer may be an inner layer and the said coating layer may be an outer layer. In this way, it is easy to coat the outer surface of the balloon with an antithrombotic material or a hydrophilic resin. Further, the base material layer may be an outer layer, and the covering layer may be an inner layer. In this way, since the forming resin for forming the coating layer generally has a lower melting point than the forming resin for forming the base material layer , it becomes easy to heat-bond the balloon to the catheter shaft. And it is preferable that both the formation resin which forms the said base material layer, and the formation resin which forms the said coating layer can be heat-seal | fused. Furthermore, the outer surface of the balloon may be coated with a hydrophilic polymer. The balloon further includes a distal taper portion formed between a distal end side of the tubular portion and a distal catheter joining portion, and a proximal end side and a proximal catheter joining portion of the tubular portion. It is preferable that the proximal end side taper part formed is provided. Furthermore, (in other words, breaking elongation) Tensile breaking strength of the formed resin forming the formation resin which forms a base layer coating layer difference is preferably 30% or less.

Moreover, what solves the said subject is a balloon catheter provided with said balloon.
In order to solve the above-mentioned problem, an inner tube having a first lumen having an open end, and an inner tube provided coaxially with the inner tube, the tip is set at a position retracted by a predetermined length from the end of the inner tube. An outer tube that forms a second lumen with the outer surface of the inner tube; a distal end portion is fixed to the inner tube; a proximal end portion is fixed to the outer tube; and an inner portion is the second tube A vasodilator catheter comprising a foldable balloon in communication with a lumen, wherein the balloon is the aforementioned catheter balloon.

  The balloon for catheter of the present invention is a balloon for catheter comprising a tubular portion and a catheter joint portion, and the balloon is formed on a base material layer made of a base material layer-forming resin and on at least one surface of the base material layer. A multilayer structure balloon having a coating layer made of a coating layer forming resin that is softer than the formed base layer forming resin, and 10% or more of the stress due to the internal pressure in a state where the maximum internal pressure is applied in the balloon The thickness of the cylindrical part is 25 μm or less. Thus, by forming a multi-layer balloon of the base layer forming resin and the base layer forming resin that is more flexible than the base layer forming resin, 10% of the stress due to the internal pressure when the maximum internal pressure is applied to the coating layer as described above. Since the above is ensured, the coating layer forming resin functions sufficiently to improve the strength of the entire balloon, and a flexible and high strength balloon can be obtained. Furthermore, since it can be made relatively thick with respect to the balloon of the base material layer forming resin, the occurrence of pin holes is small.

The catheter balloon and balloon catheter of the present invention will be described with reference to the embodiments shown in the drawings.
FIG. 1 is a cross-sectional view of an embodiment of a catheter balloon of the present invention. FIG. 4 is an explanatory diagram of a balloon molding die, and FIG. 5 is an explanatory diagram of a balloon molding stretching apparatus. 2 and 3 are cross-sectional views of another embodiment of a catheter balloon.

The catheter balloon of the present invention will be specifically described with reference to FIG.
The catheter balloon 1 includes a tubular portion 5 and catheter joint portions provided at both ends of the tubular portion. Further, the balloon 1 is more flexible than the base material layer 2 made of a high strength polymer (base material layer forming resin) and the high strength polymer (base material layer forming resin) formed on at least one surface of the base material layer 2. It has the coating layer 3 which consists of a polymer (coating layer formation resin), and the thickness of a cylindrical part is 25 micrometers or less.
The balloon 1 is more flexible than a base material layer 2 made of a high strength polymer (base material layer forming resin) and a high strength polymer (base material layer forming resin) formed on at least one surface of the base material layer 2. A multilayer structure balloon having a coating layer 3 made of a conductive polymer (a coating layer forming resin), and 10% or more of the stress due to the internal pressure in a state where the maximum internal pressure is applied in the balloon is also applied to the coating layer.

The balloon 1 is foldable, and can be folded on the outer periphery of the main tube of the catheter when not expanded. The balloon 1 has a cylindrical portion 5 having a substantially uniform outer diameter for expanding a narrowed portion of a body lumen such as a blood vessel, a ureter, and a bile duct. The cylindrical part 5 does not have to be a complete cylinder, but may be a polygonal column.
Furthermore, the balloon 1 has tapered portions 6a and 6b that are continuous to both ends of the cylindrical portion 5, and catheter joint portions 7a and 7b that are continuous with the tapered portions 6a and 6b, respectively. In other words, the balloon is formed between the distal side taper portion formed between the distal end side of the tubular portion and the distal side catheter joint portion, and the proximal end side and proximal end catheter joint portion of the tubular portion. The base end side taper part is provided.

  The cylindrical portion 5 is a portion where the maximum diameter portion of the balloon continues, and the tapered portions 6a and 6b are continuously connected to the cylindrical portion 5 so that the diameter continuously decreases toward the end portion. It is a part. The catheter joint portions 7a and 7b are portions that are continuous with the taper portions 6a and 6b, respectively, are small-diameter portions having substantially the same inner diameter, and serve as portions for attaching the balloon to the catheter. The tapered portions 6a and 6b and the catheter joint portions 7a and 7b are provided on both sides of the tubular portion 5 of the balloon, and the shapes of the respective tapered portions and the respective joint portions may be different.

  As the size of the balloon 1, the outer diameter of the tubular portion 5 when expanded is 1.0 to 35.0 mm, preferably 1.5 to 30.0 mm, and the length is 3.0 to 80. 0.0 mm, preferably 10.0 to 75.0 mm, and the total length of the balloon 1 is 5.0 to 120.0 mm, preferably 15.0 to 100.0 mm.

  Furthermore, the balloon has a thickness of at least the cylindrical portion 5 of 25 μm or less. Thus, by reducing the wall thickness, the portion that expands the blood vessel becomes flexible. In particular, the thickness of the balloon is preferably 10 to 20 μm. If the material and the two-layer structure as in the present invention have a thickness of 10 μm or more, the vascular stenosis can be reliably expanded. Note that the thickness of the balloon catheter joint portions 7a and 7b is such that the cylindrical portion 5 portion is stable in order to stabilize the joining operation and the fixation state to the catheter (specifically, an inner tube and an outer tube described later). It is good also as a thing thicker than thickness (25 micrometers or more). Conversely, in order to facilitate the folding of the balloon, it may be made thinner than the thickness of the cylindrical portion 5 portion. Since the balloon folding is particularly important in the balloon tip side taper portion 6a on the side of insertion into the blood vessel, part of the balloon tip side taper portion 6a portion is part of the cylindrical portion 5 portion. It may be thinner than the wall thickness. In addition, what is necessary is just to make it thinner than the cylindrical part 5 part about 1-5 micrometers when making a taper part thin.

  The balloon 1 is preferably biaxially stretched. Biaxial stretching refers to stretching in the extension direction of the longitudinal axis of the balloon 1 and the axis orthogonal to the longitudinal direction. By biaxially stretching, the balloon 1 can be made thin and the strength of the balloon 1 can be increased. Furthermore, it is preferable that the taper parts 6a and 6b are re-stretched. By redrawing, the thickness of the tapered portion can be made thinner.

  The balloon 1 includes a base material layer 2 made of a high-strength polymer (base material layer-forming resin) and a flexible polymer (softer polymer than the high-strength polymer (base material layer-forming resin) formed on at least one surface of the base material layer 2. It has a multilayer structure having a coating layer 3 made of a coating layer forming resin. In the embodiment of FIG. 1, the inner layer is a base material layer and the outer layer is a coating layer.

  The base material layer 2 is formed of a high-strength polymer (base material layer forming resin). The high-strength polymer (base layer-forming resin) used for forming the base layer is preferably a stretchable resin, for example, polyethylene terephthalate, a polyester in which the main acid component or main glycol component of polyethylene terephthalate is changed. (Polyethylene terephthalate), mixtures of the above polymers, polyamides (nylon 12, nylon 11, MXD6 nylon), polyarylene sulfides such as PPS (polyphenylene sulfide), and the like can be used.

  And as polyester, as the main acid component, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid, cyclohexanedicarboxylic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid , Trimellitic acid, pyromellitic acid, sulfoisophthalic acid, and their salts. Propylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol , Polytetramethylene glycol, cyclohexanedimethanol, ethylene oxide adduct of bisphenol A, trimethylolpropane, pentaerythritol, etc. Those used are considered.

  The coating layer 3 is preferably a flexible polymer (coating layer forming resin) of the same series as the high-strength polymer (base material forming resin) used for the base material layer, and is further thermoplastic and stretchable. Is preferred. By using the same series of polymers, the thermal adhesiveness or adhesion between the two layers becomes high. However, by modifying the flexible polymer (coating layer forming resin), it may be one that has improved thermal adhesion or adhesion, and even if they are not of the same series, both have thermal adhesion or adhesion. But you can. Furthermore, an adhesive layer may be provided on the base material layer and the coating layer. In this case, the adhesive layer may not be the same series.

  As the flexible polymer (polymer elastomer) used for forming the coating layer, a polyester elastomer (for example, a polyester elastomer in which the hard segment is an aromatic polyester and the soft segment is an aliphatic polyether, and the hard segment is an aromatic polyester and soft) Polyester elastomer whose segment is aliphatic polyester) and polyamide elastomer [for example, polyamide elastomer whose hard segment is polyamide (for example, nylon 12) and whose soft segment is plasticizer, polyether or polyester] can be used.

  The elongation at break is close, when the balloon is molded and pressurized until it is ruptured, the elongation of the base material layer and the elongation of the coating layer observed with pressurization are comparable, in other words, between the two layers This means that almost no peeling of the film is observed (if one is too stretched, the other cannot follow and peeling occurs between the two). Thus, in order to make elongation at break close, it is necessary to select the material which forms a base material layer and a coating layer. As one of the elements, attention can be paid to tensile elongation at break. The ratio of the tensile break elongation of the high-strength polymer (base layer forming resin) and the tensile break elongation of the flexible polymer (coating layer forming resin) is about 1: 0.7 to 1: 1.3. Is preferred. That is, if the difference in tensile elongation at break between the two polymers is 30% or less, the elongation at break between them is close and delamination hardly occurs. More preferably, the difference in tensile elongation at break between the two polymers is 20% or less. The flexible polymer (coating layer forming resin) preferably has a tensile elongation at break of 300 to 700% (ASTM D638). If it is in this range, sufficient elasticity is exhibited. More preferably, it is 350 to 600% (ASTM D638). Moreover, as a high intensity | strength polymer (base material layer forming resin), it is preferable that a tensile breaking elongation is 300 to 700% and (ASTM D638). More preferably, it is 400 to 600% (ASTM D638).

Another factor related to elongation at break is tensile strength at break. The ratio between the tensile strength at break of the high-strength polymer (base layer forming resin) and the tensile strength at break of the flexible polymer (covering layer forming resin) is about 1: 0.7 to 1: 1.3. Is preferred. That is, the difference in tensile breaking strength between the two polymers is preferably 30% or less. Moreover, as a flexible polymer (coating layer formation resin), it is preferable that a bending elastic modulus is 1000-15000 kg / cm < ² > (ASTM D790). If it is in this range, sufficient elasticity is exhibited. More preferably, it is 2000-13000 kg / cm < ² > (ASTM D790). The tensile breaking strength is preferably ^{300~400kg / cm 2 (ASTM D638)} . If it is in these ranges, it has sufficient strength.

  A preferable combination of the base layer forming resin and the covering layer forming resin is that the base layer forming resin (high-strength polymer) is polyethylene terephthalate, and the covering layer forming resin (flexible polymer) is a polyester elastomer. The material layer forming resin is polyamide, and the coating layer forming resin is a polyamide elastomer.

The thickness of the base material layer is 3 μm to 15 μm, particularly 4 μm to 12 μm is preferable, and the thickness of the coating layer is 1 μm to 15 μm, particularly 2 μm to 12 μm. Further, the thickness of the base material layer: the thickness of the coating layer is preferably 1: 0.3 to 1: 2, and particularly preferably 1: 0.5 to 1: 1.5. The thickness of these layers is determined in consideration of the resin to be used, but ensures 10% or more of the stress due to the internal pressure in the state where the maximum internal pressure is applied in the balloon, in particular, 20% or more and more Preferably, 30% or more is applied to the coating layer. Ensuring 10% or more of the stress due to the internal pressure when the maximum internal pressure is applied in the balloon means that the burst strength of the balloon provided with the base layer and the coating layer is X kg / cm ² , and only the base layer of this balloon When the burst strength of the balloon of Y is Ykg / cm ² , Y / X ≦ 0.9.

  The balloon is preferably biaxially stretched, and particularly preferably both the base material layer and the coating layer are biaxially stretched.

  The balloon is not limited to the above-described embodiment, and the outer layer may be the base material layer 2 and the inner layer may be the coating layer 3 as in the balloon 11 shown in FIG. Further, as in the balloon 21 shown in FIG. 3, the intermediate layer may be the base material layer 2, and the outer layer and the inner layer covering both surfaces may be the coating layer 3. In addition, the coating layer 3 of this Example should just ensure 10% or more of the stress by the internal pressure in the state which applied both the inner layer and the outer layer in the state which applied the maximum internal pressure in the balloon.

  The balloon is not limited to the above-described embodiment, and a base layer 2 made of a high-strength polymer (base layer-forming resin) as shown in a balloon 70 shown in FIG. A first covering layer 3 made of a flexible polymer (covering layer forming resin) having a strength polymer (base layer forming resin) and a flexible elongation point that is close to the breaking point; and formed on the outer surface of the first covering layer 3; It has the 2nd coating layer 4 formed with the highly flexible polymer softer than the flexible polymer (coating layer formation resin) which forms the 1 coating layer 3, and a thing with a thickness of 25 micrometers or less may be sufficient.

As described above, by providing the second coating layer that is more flexible outside the first coating layer, the flexibility of the balloon, that is, the trackability is further improved.
The high-strength polymer (base layer forming resin) and the flexible polymer (coating layer forming resin) are as described above. Also, the size and thickness of the balloon are the same as those described above.
As the highly flexible polymer for forming the second coating layer 4, a more flexible polymer than the above-described flexible polymer (coating layer forming resin) is used.
Highly flexible polymers (polymer elastomers) include polyester elastomers (for example, polyester elastomers with hard segments of aromatic polyester and soft segments of aliphatic polyether, hard segments of aromatic polyester and soft segments of aliphatic polyester) Elastomers) and polyamide elastomers [for example, polyamide elastomers whose hard segment is polyamide (for example, nylon 12) and whose soft segment is a plasticizer, polyether or polyester] can be used.

The ratio of the tensile break strength of the flexible polymer (coating layer forming resin) to the tensile break strength of the highly flexible polymer is preferably about 1: 0.8 to 1: 1.2. Moreover, as a highly flexible polymer, it is preferable that a bending elastic modulus is 800-4000 kg / cm < ² > (ASTM D790). If it is in this range, sufficient high elasticity is shown. More preferably, it is 1000-2000 kg / cm < ² > (ASTM D790). Moreover, it is preferable that tensile fracture strength is 200-400 kg / cm < ² > (ASTM D638). Further, the ratio of the tensile breaking strength of the flexible polymer (coating layer forming resin) to the tensile breaking elongation of the highly flexible polymer is preferably about 1: 0.8 to 1: 1.2. Moreover, as a highly flexible polymer, it is preferable that tensile elongation at break is 300 to 700%, (ASTM D638). If it is in this range, sufficient high elasticity is shown. More preferably, it is 350 to 600% (ASTM D638).

  Also in this balloon, it is preferable that 10% or more, preferably 20% or more, of the stress due to the internal pressure in the state where the maximum internal pressure is applied to the balloon is applied to the first coating layer. In the balloon of this embodiment, the combination of both the first coating layer and the second coating layer is 10% or more, preferably 20%, of the stress due to the internal pressure when the maximum internal pressure is applied in the balloon. The above may be secured.

Furthermore, the outer surface of the balloon 1 may be coated with a resin having biocompatibility, particularly antithrombotic properties. As the antithrombogenic material, for example, polyhydroxyethyl methacrylate, a copolymer of hydroxyethyl methacrylate and styrene (for example, HEMA-St-HEMA block copolymer) and the like are suitable.
Further, in order to facilitate the insertion of the balloon 1 into the blood vessel and further into the guide catheter, it is preferable to perform a treatment for exhibiting lubricity when the balloon 1 comes into contact with blood or the like. Examples of such treatment include poly (2-hydroxyethyl methacrylate), polyhydroxyethyl acrylate, hydroxypropyl cellulose, methyl vinyl ether maleic anhydride copolymer, polyethylene glycol, polyacrylamide, polyvinyl pyrrolidone, dimethylacrylamide-glycidylmeta. Examples thereof include a method of coating or fixing a hydrophilic resin such as an acrylate random or block copolymer.

Next, the manufacturing method of the balloon for catheters of this invention is demonstrated.
The balloon production method of the present invention forms a two-color (two-layer) or three-color (three-layer) polymer polymer tube (parison) composed of a stretchable and high-strength polymer and a polymer having this flexibility. . Next, the tube (parison) is stretched in the axial direction at a temperature ranging from the secondary transition temperature to the primary transition temperature of both polymers, and the stretched parison is expanded in the radial direction to be biaxially stretched. Then, the expanded parison is cooled to a temperature equal to or lower than the second-order transition temperature of both polymers, and the cooled parison is contracted to form a cylindrical portion having a substantially uniform inner diameter and a taper provided before and after the cylindrical portion, respectively. And a biaxially stretched balloon having a catheter connecting portion provided before and after the tapered portion. Then, if necessary, the taper portion of the biaxially stretched balloon is re-stretched to reduce the thickness of the taper portion, the re-stretched balloon is inflated, and the balloon is made of a high molecular polymer while maintaining the inflated state. Then, the balloon is cooled to a temperature not higher than the second order transition temperature of the polymer.

Therefore, each step will be described.
First, a tubular parison is formed from a stretchable polymer. Specifically, a tube 17 made of two kinds of high molecular polymers for forming the balloon 1 is formed. This is preferably performed by a wire coating method using two-color (two-layer) extrusion. Moreover, you may carry out by the method of previously forming a tube with the polymer which forms a base material layer or a coating layer, and coat | covering the polymer which forms the other layer on this tube. As the polymer, those described above can be used.

  And this tube 17 is inserted in the metal mold | die 10 shown in FIG. 4, and the end of the tube 17 is obstruct | occluded. The closing method is performed by closing with heat melting, high frequency sealing, forceps or the like. FIG. 4 is a cross-sectional view of the balloon molding die 10, which has a heater 12 that is a heating means and a cooling pipe 13 that is a cooling means. The inner surfaces of the separation molds 15 and 16 have a basic outer surface shape of the balloon to be formed.

  Then, as shown in FIG. 4, the heater 12 is operated, and the tube 17 that forms the balloon 1 is moved to a temperature in the range from the second order transition temperature to the first order transition temperature of the high molecular weight polymer. Heat to a temperature slightly above the next transition temperature. The portion that is heated in the mold 10 by maintaining the tube 17 in a heated state, extending the tube 17 in the directions of the arrows X and Y, and further feeding the tube 17 while pressurizing the gas in the direction of the arrow Z. The tube 17 is closely attached to the inner wall surfaces of the separation molds 15 and 16. And a cooling fluid is circulated in the cooling pipe 13, and the tube 17 is cooled below to a secondary transition temperature. In addition, this cooling may be performed by simply leaving it alone without circulating the coolant amount. Thereafter, the inside of the tube 17 is brought to normal pressure, and the tube 17 is removed from the mold 10. And the basic shape of a balloon as shown in FIG. 4 is formed by cut | disconnecting the tube 17 in the front-end | tip part and rear-end part of the tube 17. As shown in FIG. Moreover, you may form the target thick balloon by performing the said extending | stretching process twice or more.

  Then, the taper portions 6a and 6b of the biaxially stretched balloon may be re-stretched to reduce the thickness of the taper portion. FIG. 5 is a cross-sectional view of a re-stretching jig for re-stretching the tapered portions 6a, 6b or the tapered portions 6a, 6b and the catheter joint portions 7a, 7b. The jig 20 is for fixing two balloons. It has chucks 25a and 25b, and the fixing chuck 25b is movably attached to the support base 28. The fixing chuck 25b is configured to move back and forth by rotating the handle 22. Has been.

Next, the balloon catheter for vasodilation according to the present invention will be described with reference to the embodiments shown in the drawings.
6 is an external view of a balloon catheter for vasodilation, FIG. 7 is a sectional view of the distal end portion of the catheter, and FIG. 8 is a sectional view of the proximal end portion of the catheter.
As shown in FIG. 6, the balloon catheter 30 of the present invention comprises a catheter body, a balloon 1, and a hub 31 attached to the proximal end of the catheter body.
Specifically, as shown in FIGS. 7 and 8, the balloon catheter 30 includes an inner tube 24 having a first lumen 34 having an open end, and is provided coaxially with the inner tube 24. An outer tube 35 which is provided at a position retracted by a predetermined length from the distal end of 24 and forms a second lumen 36 with the outer surface of the inner tube 24; a catheter joint (balloon tip) 7a; a catheter joint (balloon) A foldable balloon 1 having a base end portion 7b, the joint portion 7b attached to the outer tube 35, the joint portion 7a attached to the inner tube 24, and communicating with the second lumen 36 in the vicinity of the base end portion. It is equipped with.

This balloon catheter 30 is an embodiment applied to a vascular dilatation catheter. The catheter 30 is formed of a catheter body having an inner tube 24, an outer tube 35, and a branch hub 31, and the balloon 1.
The inner tube 24 has a first lumen 34 whose tip is open. The first lumen 34 is a lumen for inserting a guide wire, and communicates with a first opening 39 that forms a guide wire port provided in a branch hub 31 described later.

The inner tube 24 has an outer diameter of 0.30 to 2.50 mm, preferably 0.40 to 2.00 mm, and an inner diameter of 0.20 to 2.35 mm, preferably 0.25 to 1.70 mm. .
As a material for forming the inner tube 24, a material having a certain degree of flexibility is preferable. For example, polyolefin such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyurethane, Thermoplastic resins such as polyamide, polyamide elastomer, and polyester elastomer can be used.

The outer tube 35 is inserted into the inner tube 24 and is provided at a position where the tip is slightly retracted from the tip of the inner tube. The second lumen 36 is formed by the inner surface of the outer tube 35 and the outer surface of the inner tube 24. Is formed. Therefore, the lumen can have a sufficient volume. The second lumen 36 communicates at the tip thereof with the inside of the balloon 1 to be described later and the rear end thereof, and the rear end of the second lumen 36 receives a fluid (for example, an angiographic agent) for inflating the balloon. It communicates with the second opening 41 of the branch hub 31 that forms an injection port for injection.
The outer tube 35 has an outer diameter of 0.50 to 4.30 mm, preferably 0.60 to 4.00 mm, and an inner diameter of 0.40 to 3.80 mm, preferably 0.50 to 3.00 mm. .

  As a material for forming the outer tube 35, a material having a certain degree of flexibility is preferable. For example, polyolefin such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyurethane, Thermoplastic resins such as polyamide, polyamide elastomer, and polyester elastomer can be used.

  The balloon 1 is foldable, and can be folded on the outer periphery of the inner tube 24 when not expanded. The balloon 1 is foldable and has a cylindrical portion 5 having substantially the same diameter, at least a portion of which is cylindrical so that the stenosis of the blood vessel can be easily expanded. The cylindrical portion may not be a perfect cylinder, but may be a polygonal column. The balloon 1 has its joint 7b fixed to the tip of the outer tube 35 in a liquid-tight manner by an adhesive or heat fusion. Similarly, the joint 7a is also liquid-tightly fixed to the tip of the inner tube 24.

As shown in FIG. 7, the balloon 1 forms an expansion space 45 between the inner surface of the balloon 1 and the outer surface of the inner tube 24. The expansion space 45 communicates with the second lumen 36 at the entire periphery at the rear end. As described above, since the second lumen having a relatively large volume is communicated with the rear end of the balloon 1, it is easy to inject the inflation fluid into the balloon 1 through the second lumen.
As the balloon 1, those described above are used.

  Further, it is preferable to provide one or more markers 44 on the outer surface of the inner tube 24 so that the position of the cylindrical portion 5 of the balloon 1 can be confirmed by X-ray contrast imaging. As shown in FIG. 7, the marker 44 is positioned near the rear end side of the balloon 1 to the inner tube 24 and near the distal end of the balloon 1 and the outer tube 35. It is preferable to have both end portions at portions located at both ends of the cylindrical portion 5 and have a length equivalent to the length of the cylindrical portion 5 of the balloon 1. The marker 44 is preferably formed of a radiopaque material (for example, gold, platinum, tungsten, or an alloy thereof, or a silver-palladium alloy). Furthermore, the form of the marker 44 is preferably a coil spring as shown in FIG. 7, and it is more preferable that 1 to 4 mm, preferably 2 to 3 mm are wound from both ends of the marker 44 closely. This is to make it possible to easily confirm the position of the balloon 1 under X-ray fluoroscopy, and further, by using a spring shape, reinforcement that prevents bending and collapsing at the bent portion of the inner tube located in the balloon. Forming the body is preferable.

  In particular, if the marker 44 is formed by a single spring coil and is wound around the outer periphery of the inner tube 24 by tight winding, the resistance to external force becomes stronger. Further, if the cross-sectional shape of the coiled linear body is any one of a circle, a square, and an ellipse, the proof strength against an external force becomes stronger.

  The branch hub 31 has a first opening 39 that communicates with the first lumen 34 and forms a guide wire port, and an inner tube hub 52 fixed to the inner tube 24 and an injection that communicates with the second lumen. It has a second opening 41 that forms a port, and an outer tube hub 53 fixed to the outer tube 35. The outer tube hub 53 and the inner tube hub 52 are fixed. As a material for forming the branched hub, thermoplastic resins such as polycarbonate, polyamide, polysulfone, polyarylate, and methacrylate-butylene-styrene copolymer can be preferably used.

  And in the Example shown in FIG. 8, it has the tube 50 for bending prevention in the terminal part of the outer tube | pipe 35. As shown in FIG. The bending prevention tube 50 has heat shrinkability, and is formed so that the inner diameter after heat shrinkage is slightly smaller than the outer diameter of the outer tube 35. The tube 50 having heat shrinkability is formed on the outer tube 35. It can be easily attached by being fitted on the end portion and contracted by heating (for example, applying hot air). The bending prevention tube 50 is fixed to the outer tube hub 53 by a stop pin 61. In this fixing method, a retaining pin 61 having a rear end portion having an enlarged diameter is inserted at the rear end of the outer tube 35 so that the outer diameter of the portion other than the rear end portion is substantially equal to the inner diameter of the outer tube 35. Inserting into the outer tube hub 53 from the front end and pushing the projection 54 provided on the inner surface of the outer tube hub 53 until the rear end portion of the set pin 61 passes over. Further, an adhesive may be applied and fixed to the contact surface between the outer tube hub 53 and the bending prevention tube 50. As a material for forming the outer tube hub, a thermoplastic resin such as polycarbonate, polyamide, polysulfone, polyarylate, methacrylate-butylene-styrene copolymer can be suitably used.

  In addition, a bending prevention tube 60 is provided at the end of the inner tube 24. This tube 60 has heat shrinkability, and is formed so that the inner diameter after heat shrinkage is slightly smaller than the outer diameter of the inner tube 24, and the tube 60 having heat shrinkability is formed at the end of the inner tube 24. It can be attached easily by fitting and shrinking by heating (for example, applying hot air). The inner tube 24 to which the bending preventing tube 60 is attached is fixed to the inner tube hub 52. In this fixing method, a stopper pin 62 having a rear end portion whose diameter is increased is inserted into the rear end of the inner tube 24 and the outer diameter of the portion other than the rear end portion is substantially equal to the inner diameter of the inner tube 24. Inserting into the inner tube hub 52 from the front end and pushing the protrusion 64 provided on the inner surface of the inner tube hub 52 until the rear end portion of the set pin 62 passes over. Further, an adhesive may be applied and fixed to the contact surface between the inner tube hub 52 and the bending prevention tube 60. As the material for forming the inner tube hub, thermoplastic resins such as polycarbonate, polyamide, polysulfone, polyarylate, and methacrylate-butylene-styrene copolymer can be suitably used. As shown in FIG. 8, the inner tube hub 52 and the outer tube hub 53 are fixed. This fixing is performed by inserting and joining the inner tube 24 from the rear end of the outer tube hub 53 attached to the proximal end portion of the outer tube 35. At this time, by applying an adhesive to the joint between the inner tube hub 52 and the outer tube hub 53, both can be securely fixed.

  Further, a tube having a port member that forms an opening at the rear end may be liquid-tightly attached to each of the first lumen and the second lumen without providing the branch hub. The structure of the catheter is not limited to the over-the-wire type as described above, but may be an on-the-wire type.

Specific examples of the catheter balloon of the present invention will be described below.
(Example 1)
High molecular weight polyethylene terephthalate PET having an intrinsic viscosity of about 1.1 (made by Nippon Unipet Co., Ltd., trade name: Unipet RT580CA, tensile) as a base layer forming polymer (base layer forming resin, inner layer forming polymer, high strength polymer) breaking strength 600kg ^/ cm 2 (ASTMD638), flexural modulus 24000kg ^/ cm 2 (ASTMD790), tensile break elongation 500% (ASTMD638)] was used. Polyester elastomer (product name: Perprene P-150B, manufactured by Toyobo Co., Ltd., hard segment is aromatic polyester and soft segment is aliphatic polyether) as coating layer forming polymer (covering layer forming resin, outer layer forming polymer, flexible polymer) Polyester elastomer, tensile breaking strength 390 kg / cm ² (ASTMD638), flexural modulus 2,950 kg / cm ² (ASTMD790), tensile elongation at break 550% (ASTMD638)].

Using these, co-extrusion by an ordinary wire coating method was performed to produce a two-layer tube having an inner layer of PET and an outer layer of a polyester elastomer. The inner diameter of the tube is 0.45 mm (the inner layer has a wall thickness of 0.11 mm), the outer diameter is 0.85 mm (the outer layer has a wall thickness of 0.09 mm), and the sectional area ratio of the inner and outer layers (balloon) The inner layer / outer layer = 1/1. This tube is placed in the mold shown in FIG. 4, heated to 150 ° C., stretched about twice in the axial direction, and air is sent into the tube (parison) to bring it into close contact with the mold. A shape was made. In addition, as for the extending | stretching rate of the radial direction of a cylindrical part, the internal diameter was about 6 times and the outer diameter was about 3 times. The balloon, in water at 37 ° C., the outer diameter when the inner balloon was pressurized with 1 kg / cm ² with nitrogen is 2.85 mm, the wall thickness of a maximum outer diameter of the balloon (cylindrical portion) It was 10 μm. The thickness of the PET layer at the outermost diameter portion of the balloon was 5 μm.

(Example 2)
As a coating layer forming polymer (coating layer forming resin, outer layer forming polymer, flexible polymer), a polyester elastomer [manufactured by Toyobo Co., Ltd., trade name: Perprene P-450B, hard segment is aromatic polyester, soft segment is aliphatic polyether The same procedure as in Example 1 was conducted, except that a polyester elastomer, a tensile breaking strength of 354 kg / cm ² (ASTMD 638), a flexural modulus of 12,930 kg / cm ² (ASTMD 790), and a tensile elongation at break of 440% (ASTMD 638)] were used. A two-layer tube having the same dimensions was formed. Using this tube, a balloon was prepared in the same manner as in Example 1. The balloon, in water at 37 ° C., the outer diameter when the inner balloon was pressurized with 1 kg / cm ² with nitrogen is 2.85 mm, the wall thickness of a maximum outer diameter of the balloon (cylindrical portion) It was 10 μm.

(Example 3)
Using the same material as in Example 1, the inner diameter of the tube is 0.45 mm (the thickness of the inner layer is 0.11 mm), the outer diameter is 0.91 mm (the thickness of the outer layer is 0.12 mm), An inner / outer layer having a cross-sectional area ratio of inner layer / outer layer = 1 / 1.5 was prepared, and a balloon was prepared in the same manner as in Example 1. The thickness of the polyethylene terephthalate layer at the outermost diameter portion of the balloon was 5 μm, the thickness of the polyester elastomer layer was 7.5 μm, and the outer diameter when pressurized at 1 kg / cm ² was 2.85 mm.

Example 4
As the base layer forming polymer (base layer forming resin) and the coating layer forming polymer, the same ones as in Example 1 were used. Using these, co-extrusion by a conventional wire coating method was performed so that the base material layer was the outer layer and the coating layer was the inner layer, and a two-layer tube having an outer layer of polyethylene terephthalate and an inner layer of a polyester elastomer was produced. The inner diameter of the tube is 0.45 mm (the thickness of the inner layer is 0.11 mm), the outer diameter is 0.85 mm (the thickness of the outer layer is 0.09 mm), and the cross-sectional area ratio of the inner and outer layers is the inner layer / Outer layer = 1/1. Using this tube, a balloon was produced in the same manner as in Example 1. The balloon, in water at 37 ° C., the outer diameter when the inner balloon was pressurized with 1 kg / cm ² with nitrogen is 2.85 mm, the wall thickness of a maximum outer diameter of the balloon (cylindrical portion) It was 10 μm.

(Example 5)
As the base layer forming polymer (base layer forming resin) and the coating layer forming polymer, the same ones as in Example 1 were used. Using these, so that the base layer is an intermediate layer and the coating layer covers both sides of the base layer, three-color extrusion is performed by a conventional wire coating method, the intermediate layer is polyethylene terephthalate, and the inner and outer layers are polyester. An elastomer three-layer tube was prepared. The inner diameter of the tube is 0.45 mm (inner layer thickness is 0.05 mm), and outer diameter is 0.85 mm (intermediate layer thickness is 0.10 mm, outer layer thickness is 0.05 mm). The cross-sectional area ratio of the inner and outer layers was intermediate layer / (inner layer + outer layer) = 1/1. This tube was placed in the mold shown in FIG. 4, heated to 150 ° C., stretched twice in the axial direction, and air was sent into the tube (parison) to closely adhere to the mold to produce a balloon. . In addition, as for the extending | stretching rate of the radial direction of a cylindrical part, the internal diameter was about 6 times and the outer diameter was about 3 times. The balloon, in water at 37 ° C., the outer diameter when the inner balloon was pressurized with 1 kg / cm ² with nitrogen is 2.85 mm, the wall thickness of a maximum outer diameter of the balloon (cylindrical portion) It was 10 μm.

(Comparative Example 1)
Using polyethylene terephthalate used in Example 1, a single-layer tube having an inner diameter of 0.45 mm and an outer diameter of 0.67 mm (wall thickness: 0.11 mm) was formed by a wire coating method. Using this tube, a balloon was prepared in the same manner as in Example 1. This balloon has an outer diameter of 2.85 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (tubular portion) of the balloon is It was 5 μm.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that linear low density polyethylene (manufactured by Mitsubishi Chemical Corporation, trade name Mitsubishi Polyethylene C6, SF520, tensile elongation at breakage 800% (ASTM D638)) was used as the coating layer forming polymer (outer layer material). A two-layer tube having the same dimensions was molded, and a balloon was produced in the same manner as in Example 1 except that the heat set temperature was set to 105 ° C. The balloon was immersed in water at 37 ° C. When the inside of the balloon was pressurized with nitrogen at 1 kg / cm ² , the outer diameter was 2.85 mm, and the wall thickness at the maximum outer diameter portion (cylindrical portion) of the balloon was 10 μm.

[Experiment 1]
The burst strength was measured when the balloons of Examples 1 to 5, Comparative Example 1 and Comparative Example 2 were blown into water at 37 ° C. by blowing nitrogen into the interior at 1 kg / cm ² increments.
The results were as shown in Table 1.

(Table 1)
┌──────┬──────────┬───────────────┐
│ │ Burst strength │ Stress ratio at the time of rupture of coating layer │
├──────┼──────────┼───────────────┤
│ Example 1 │ 18kg / cm ² │ 28% │
├──────┼──────────┼───────────────┤
│ Example 2 │ 19kg / cm ² │ 32% │
├──────┼──────────┼───────────────┤
│ Example 3 │ 20kg / cm ² │ 35% │
├──────┼──────────┼───────────────┤
│ Example 4 │ 18kg / cm ² │ 28% │
├──────┼──────────┼───────────────┤
│ Example 5 │ 18kg / cm ² │ 28% │
├──────┼──────────┼───────────────┤
│ Comparative Example 1 │ 13 kg / cm ² │ ---
├──────┼──────────┼───────────────┤
│ Comparative Example 2 │ 14kg / cm ² │ 7% │
└──────┴──────────┴───────────────┘

In Example 1, Comparative Example 1 and Comparative Example 2, since the thickness of the polyethylene terephthalate layer (base material layer) is 5 μm, the stress applied to the polyester elastomer (coating layer) in Example 1 is 5 kg / cm ^2. The stress applied to the linear low density polyethylene (coating layer) in Comparative Example 2 is 1 kg / cm ² . The ratio of the stress secured by the coating layer to the total stress was about 28% and 7%, respectively. Similarly, the stress burden rate was calculated also about the other Example and the comparative example.

From this, when the strength of the wall surface of each layer of the balloon is calculated by the known membrane equation shown below (see Japanese Patent Publication No. 2-28341, Japanese Patent Laid-Open No. 63-183070), the strength of the polyester elastomer is 1425 kg / cm. ² and the strength of the linear low density polyethylene was 285 kg / cm ² .
S = 1000PD / 2t (membrane equation)
S: Wall strength (kg / cm ² ), P: Internal pressure at the time of rupture (kg / cm ² )
D: 1kg / cm ² pressurized balloon outer diameter (mm)
t: Balloon outermost wall thickness (μm)

Polyester elastomers showed sufficient strength, but linear low density polyethylene far exceeded the breaking point strength (390 kg / cm ² ) in the catalog, and it was between the yield point strength (140 kg / cm ² ) and the breaking point strength. Only a moderate strength was shown. This is because the polyethylene terephthalate and linear low density polyethylene have the maximum elongation (elongation at break) smaller than that of polyethylene terephthalate, so when a stress is applied to the balloon (when pressurized), the linear low density polyethylene layer This is because the polyethylene terephthalate layer reaches its maximum elongation before reaching its maximum elongation (elongation at break), and breaks. For this reason, it is considered that the strength of the linear low density polyethylene showed only a value intermediate between the yield strength and the fracture strength.

  Polyester elastomers, on the other hand, have a maximum elongation (elongation at break) close to that of polyethylene terephthalate, and furthermore, the temperature when molding into a balloon is lower than the melting point of the polyester elastomer, so the polyester elastomer is fixed in a biaxially stretched state. For this reason, it is estimated that the calculated strength is much larger than the breaking point strength on the catalog.

(Example 6)
As the base layer forming polymer (base layer forming resin, inner layer forming polymer), polyamide [nylon 12, trade name Grillamide L25, manufactured by EMS-CHEMIE AG, tensile breaking strength 500 kg / cm ² (ASTM D638), flexural modulus 12000 kg / Cm ² (ASTMD790), tensile elongation at break 270% (ASTMD638)], and as a coating layer forming polymer (outer layer forming polymer), a polyamide elastomer (manufactured by Atchem Co., Ltd., trade name Pebax 6333SA01, hard segment is a polyamide and a soft segment polyamide elastomer but aliphatic polyether, tensile strength 520kg ^/ cm 2 (ASTMD638), flexural modulus 3,500kg ^/ cm 2 (ASTMD790), tensile break elongation 300% (ASTM D638 ] Was used.

Using these, co-extrusion by an ordinary wire coating method was performed to produce a two-layer tube having an inner layer of polyamide and an outer layer of polyamide elastomer. The inner diameter of the tube is 0.45 mm (the inner layer thickness is 0.18 mm), the outer diameter is 0.90 mm (the outer layer thickness is 0.045 mm), and the cross-sectional area ratio of the inner and outer layers is the inner layer. / Outer layer = 3/1. This tube is placed in the mold shown in FIG. 4, heated to 140 ° C. and stretched 1.8 times in the axial direction, and air is sent into the tube (parison) to bring it into close contact with the mold. A basic shape was produced. In addition, as for the draw ratio of the cylindrical part, the inner diameter was about 5.5 times and the outer diameter was about 2.8 times. This balloon has an outer diameter of 2.52 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (tubular portion) of the balloon is It was 20 μm.

(Example 7)
Using the same material as in Example 6, the inner diameter of the tube is 0.45 mm (the thickness of the inner layer is 0.24 mm), the outer diameter is 0.98 mm (the thickness of the outer layer is 0.085 mm), The inner and outer layers had a cross-sectional area ratio of inner layer / outer layer = 3/2, and balloons were prepared in the same manner as in Example 6. The thickness of the polyamide layer at the outermost diameter portion of the balloon was 15 μm, the thickness of the polyamide elastomer layer was 10 μm, and the outer diameter when pressurized at 1 kg / cm ² was 2.52 mm.

(Example 8)
As the base layer forming polymer (base layer forming resin) and the coating layer forming polymer, the same ones as in Example 6 were used. Using these, co-extrusion by a conventional wire coating method was carried out so that the base material layer was the outer layer and the coating layer was the inner layer, and a two-layer tube having a polyamide outer layer and a polyamide elastomer inner layer was produced. The inner diameter of the tube is 0.45 mm (the thickness of the inner layer is 0.075 mm), the outer diameter is 0.90 mm (the thickness of the outer layer is 0.15 mm), and the cross-sectional area ratio of the inner and outer layers is the inner layer / Outer layer = 1/3. Using this tube, a balloon was produced in the same manner as in Example 6. This balloon has an outer diameter of 2.52 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (tubular portion) of the balloon is It was 20 μm.

Example 9
The same material as in Example 6 was used as the base material layer forming polymer (base material layer forming resin) and the coating layer forming polymer. Using these, so that the base layer is an intermediate layer and the coating layer covers both sides of the base layer, three-color extrusion is performed by a conventional wire coating method, the intermediate layer is polyamide, and the inner layer and the outer layer are polyamide elastomers. A three-layer tube was prepared. The inner diameter of the tube is 0.45 mm (inner layer thickness is 0.025 mm), and the outer diameter is 0.90 mm (intermediate layer thickness is 0.17 mm, outer layer thickness is 0.03 mm). The cross-sectional area ratio of the inner and outer layers was intermediate layer / (inner layer + outer layer) = 3/1. Using this tube, a balloon was prepared in the same manner as in Example 6. This balloon has an outer diameter of 2.52 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (tubular portion) of the balloon is It was 20 μm.

(Comparative Example 3)
Using the polyamide used in Example 6, a single-layer tube having an inner diameter of 0.45 mm and an outer diameter of 0.81 mm (thickness 0.18 mm) was formed by a wire coating method. Using this tube, a balloon was prepared in the same manner as in Example 6. This balloon has an outer diameter of 2.52 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (tubular portion) of the balloon is It was 15 μm.

[Experiment 2]
The burst strength was measured when the balloons of Examples 6 to 9 and Comparative Example 3 were blown into water at 37 ° C. by blowing nitrogen into the interior at 1 kg / cm ² increments. Moreover, the stress burden rate was computed from this result.
The results were as shown in Table 2.

(Table 2)
┌─────┬──────────┬────────────────┐
│ │ Burst strength │ Stress ratio at the time of rupture of coating layer │
├─────┼──────────┼────────────────┤
│ Example 6│ 22kg / cm ² │ 13.6% │
├─────┼──────────┼────────────────┤
│ Example 7│ 25kg / cm ² │ 24% │
├─────┼──────────┼────────────────┤
│ Example 8│ 22kg / cm ² │ 13.6% │
├─────┼──────────┼────────────────┤
│ Example 9│ 22kg / cm ² │ 13.6% │
├─────┼──────────┼────────────────┤
│ Comparative Example 3 │ 19kg / cm ² │ -----
└─────┴──────────┴────────────────┘

(Example 10)
High molecular weight polyethylene terephthalate PET having an intrinsic viscosity of about 1.1 (made by Nippon Unipet Co., Ltd., trade name: Unipet RT580CA, tensile) as a base layer forming polymer (base layer forming resin, inner layer forming polymer, high strength polymer) breaking strength 600kg ^/ cm 2 (ASTMD638), flexural modulus 24000kg ^/ cm 2 (ASTMD790), tensile break elongation 500% (ASTMD638)] was used.

As the first coating layer forming polymer (intermediate layer forming polymer, flexible polymer), a polyester elastomer [manufactured by Toyobo Co., Ltd., trade name: Perprene P-150B, hard segment is aromatic polyester and soft segment is aliphatic polyether] polyester elastomer, tensile strength 390kg ^/ cm 2 (ASTMD638), flexural modulus 2,950kg ^/ cm 2 (ASTMD790), tensile break elongation 550% (ASTMD638)] was used.

As the second coating layer forming polymer (outer layer forming polymer, highly flexible polymer), polyester elastomer [made by Toyobo Co., Ltd., trade name: Perprene P-150M, hard segment is aromatic polyester and soft segment is aliphatic polyether Polyester elastomer, tensile breaking strength 380 kg / cm ² (ASTM D638), flexural modulus 1,200 kg / cm ² (ASTM D 790), tensile breaking elongation 420% (ASTM D638)] were used.

Using these, three-color extrusion is performed by a conventional wire coating method so that the base layer is an inner layer, the first coating layer is an intermediate layer, and the second coating layer is an outer layer, and the inner layer is polyethylene terephthalate. Thus, a three-layer tube having a polyester elastomer as an intermediate layer and an outer layer was produced. The inner diameter of the tube is 0.30 mm, the outer diameter is 0.66 mm, the thickness of the base material layer is 0.1 mm, the thickness of the intermediate layer (first covering layer) is 0.03 mm, and the outer layer (second The thickness of the coating layer was 0.05 mm. This tube was placed in the mold shown in FIG. 4, heated to 150 ° C., stretched twice in the axial direction, and air was sent into the tube (parison) to closely adhere to the mold to produce a balloon. . In addition, as for the extending | stretching rate of the radial direction of a cylindrical part, the internal diameter was about 6 times and the outer diameter was about 3 times. This balloon has an outer diameter of 2.0 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (cylindrical portion) of the balloon is The thickness of the base material layer was 5 μm, the thickness of the intermediate layer (first coating layer) was 2 μm, and the thickness of the outer layer (second coating layer) was 5 μm.

(Example 11)
Using the same material as in Example 10, three-color extrusion was performed by a conventional wire coating method to prepare a three-layer tube having an inner layer made of polyethylene terephthalate and an intermediate layer and an outer layer made of a polyester elastomer. The inner diameter of the tube is 0.42 mm, the outer diameter is 0.8 mm, the thickness of the base material layer is 0.095 mm, the thickness of the intermediate layer (first covering layer) is 0.025 mm, and the outer layer (first The thickness of the coating layer 2 was 0.07 mm. This tube was placed in the mold shown in FIG. 4, heated to 150 ° C., stretched twice in the axial direction, and air was sent into the tube (parison) to closely adhere to the mold to produce a balloon. . In addition, as for the extending | stretching rate of the radial direction of a cylindrical part, the internal diameter was about 6 times and the outer diameter was about 3 times. This balloon has an outer diameter of 2.5 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (cylindrical portion) of the balloon is The thickness of the base layer is 6.0 μm, the thickness of the intermediate layer (first coating layer) is 2 μm, and the thickness of the outer layer (second coating layer) is 5.5 μm. there were.

(Example 12)
Using the same material as in Example 10, three-color extrusion was performed by a conventional wire coating method to prepare a three-layer tube having an inner layer made of polyethylene terephthalate and an intermediate layer and an outer layer made of a polyester elastomer. The inner diameter of the tube is 0.45 mm, the outer diameter is 0.9 mm, the thickness of the base material layer is 0.11 mm, the thickness of the intermediate layer (first covering layer) is 0.035 mm, and the outer layer (first The thickness of the coating layer 2 was 0.08 mm. This tube was placed in the mold shown in FIG. 4, heated to 150 ° C., stretched twice in the axial direction, and air was sent into the tube (parison) to closely adhere to the mold to produce a balloon. . In addition, as for the extending | stretching rate of the radial direction of a cylindrical part, the internal diameter was about 6 times and the outer diameter was about 3 times. This balloon has an outer diameter of 2.75 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (tubular portion) of the balloon is The thickness of the base layer is 6.5 μm, the thickness of the intermediate layer (first coating layer) is 2.5 μm, and the thickness of the outer layer (second coating layer) is 7 μm. there were.

(Example 13)
Using the same material as in Example 10, three-color extrusion was performed by a conventional wire coating method to prepare a three-layer tube having an inner layer made of polyethylene terephthalate and an intermediate layer and an outer layer made of a polyester elastomer. The inner diameter of the tube is 0.5 mm, the outer diameter is 1.0 mm, the thickness of the base material layer is 0.115 mm, the thickness of the intermediate layer (first covering layer) is 0.035 mm, and the outer layer (first The thickness of the coating layer 2 was 0.1 mm. This tube was placed in the mold shown in FIG. 4, heated to 150 ° C., stretched twice in the axial direction, and air was sent into the tube (parison) to closely adhere to the mold to produce a balloon. . In addition, as for the extending | stretching rate of the radial direction of a cylindrical part, the internal diameter was about 6 times and the outer diameter was about 3 times. This balloon has an outer diameter of 3.0 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (tubular portion) of the balloon is The thickness of the base layer is 6.5 μm, the thickness of the intermediate layer (first coating layer) is 2.5 μm, and the thickness of the outer layer (second coating layer) is 8 μm. there were.

(Example 14)
Using the same material as in Example 10, three-color extrusion was performed by a conventional wire coating method to prepare a three-layer tube having an inner layer made of polyethylene terephthalate and an intermediate layer and an outer layer made of a polyester elastomer. The inner diameter of the tube is 0.53 mm, the outer diameter is 1.05 mm, the thickness of the base material layer is 0.12 mm, the thickness of the intermediate layer (first covering layer) is 0.04 mm, and the outer layer (first The thickness of the coating layer 2 was 0.1 mm. This tube was placed in the mold shown in FIG. 4, heated to 150 ° C., stretched twice in the axial direction, and air was sent into the tube (parison) to closely adhere to the mold to produce a balloon. . In addition, as for the extending | stretching rate of the radial direction of a cylindrical part, the internal diameter was about 6 times and the outer diameter was about 3 times. This balloon has an outer diameter of 3.25 mm when the inside of the balloon is pressurized with nitrogen at 1 kg / cm ² in water at 37 ° C., and the wall thickness at the maximum outer diameter portion (tubular portion) of the balloon is The thickness of the base layer is 7.0 μm, the thickness of the intermediate layer (first coating layer) is 3.0 μm, and the thickness of the outer layer (second coating layer) is 9 μm. there were.

(Example 15)
Using the same material as in Example 10, three-color extrusion was performed by a conventional wire coating method to prepare a three-layer tube having an inner layer made of polyethylene terephthalate and an intermediate layer and an outer layer made of a polyester elastomer. The inner diameter of the tube is 0.55 mm, the outer diameter is 1.10 mm, the thickness of the base material layer is 0.125 mm, the thickness of the intermediate layer (first covering layer) is 0.05 mm, and the outer layer (first The thickness of the coating layer 2 was 0.1 mm. This tube was placed in the mold shown in FIG. 4, heated to 150 ° C., stretched twice in the axial direction, and air was sent into the tube (parison) to closely adhere to the mold to produce a balloon. . In addition, as for the extending | stretching rate of the radial direction of a cylindrical part, an internal diameter was about 8 times and an outer diameter was about 3.5 times. The balloon, in water at 37 ° C., the outer diameter when the balloon interior pressurized with 1 kg / cm ² with nitrogen is 3.5 mm, the wall thickness of a maximum outer diameter of the balloon (cylindrical portion) The thickness of the substrate layer is 7.5 μm, the thickness of the intermediate layer (first coating layer) is 3.5 μm, and the thickness of the outer layer (second coating layer) is 9 μm. there were.

[Experiment 3]
The burst strength was measured when the balloons of Examples 10 to 15 were blown into water at 37 ° C. by blowing nitrogen into the interior in increments of 1 kg / cm ² .
The results were as shown in Table 3.

(Table 3)
┌──────┬──────────┬───────────────┐
│ │ Burst strength │ Stress ratio at the time of rupture of coating layer │
├──────┼──────────┼───────────────┤
│ Example 10│ 24kg / cm ² │ 23% │
├──────┼──────────┼───────────────┤
│ Example 11 │ 23kg / cm ² │ 23% │
├──────┼──────────┼───────────────┤
│ Example ^{12│ 22kg / cm 2 │ 20%} │
├──────┼──────────┼───────────────┤
│ Example 13 │ 21 kg / cm ² │ 24% │
├──────┼──────────┼───────────────┤
│ Example 14│ 20kg / cm ² │ 20% │
├──────┼──────────┼───────────────┤
│ Example 15│ 20kg / cm ² │ 20% │
└──────┴──────────┴───────────────┘

(Note that the stress burden rate at the time of bursting of the coating layer is the sum of the stress burden rates of the first coating layer and the second coating layer.)

FIG. 1 is a cross-sectional view of an embodiment of a catheter balloon of the present invention. FIG. 2 is a sectional view of a catheter balloon according to another embodiment. FIG. 3 is a sectional view of a catheter balloon according to another embodiment. FIG. 4 is an explanatory diagram of a balloon molding die. FIG. 5 is an explanatory diagram of a balloon molding stretcher. FIG. 6 is an external view of a balloon catheter for vasodilation. FIG. 7 is a cross-sectional view of the distal end portion of the catheter. FIG. 8 is a cross-sectional view of the proximal end portion of the catheter. FIG. 9 is a sectional view of a catheter balloon of another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Balloon for catheters 2 Base material layer 3 Coating layer 4 2nd coating layer (highly flexible polymer)
30 balloon catheter

Claims (10)

A balloon for a catheter comprising a tubular part and a catheter joint part, the balloon comprising a base material layer made of a stretchable thermoplastic resin, and the base material layer formed on at least one surface of the base material layer A balloon for a catheter having a multilayer structure having a coating layer made of a thermoplastic resin that is more flexible and stretchable than a resin forming the resin, and has a tensile breaking strength between the resin forming the base layer and the resin forming the coating layer Difference is 30% or less, and the balloon for catheter is a biaxially stretched balloon in which both the base material layer and the coating layer are biaxially stretched, and the thickness of the tubular portion is 25 μm or less. der is, and a balloon catheter in which the biaxially 10% or more of the stress due to internal pressure in the state of applying the maximum pressure in the stretching balloon, characterized in that according to the coating layer. The catheter balloon according to claim 1, wherein 20% or more of the stress due to the internal pressure when the maximum internal pressure is applied to the balloon is applied to the coating layer. Differences in tensile elongation at break of the resin for forming the coating layer and the resin for forming the substrate layer, the catheter balloon of claim 1 or 2 is 30% or less. The resin forming the coating layer, the catheter balloon of any one of claims 1 to 3 is a polymeric resin and the sequence of forming the base layer. The resin forming the base layer is polyethylene terephthalate, the catheter balloon of claim 4 resin forming the coating layer is a polyester elastomer. The resin forming the base layer is a polyamide, a catheter balloon of claim 4 resin forming the coating layer is a polyamide elastomer. The base layer is the inner layer, the catheter balloon of any one of claims 1 to 6 wherein the coating layer is an outer layer. The balloon is formed between a distal side taper portion formed between a distal end side of the tubular portion and a distal side catheter joint portion, and a proximal end side and proximal end catheter joint portion of the tubular portion. The catheter balloon according to any one of claims 1 to 7, further comprising a proximal-side tapered portion. A balloon catheter comprising the catheter balloon according to any one of claims 1 to 8 . An inner tube having a first lumen that is open at the tip, and a coaxial shaft provided on the inner tube, having a tip at a position retracted by a predetermined length from the tip of the inner tube, and an outer surface of the inner tube An outer tube that forms a second lumen therebetween, a foldable balloon having a distal end fixed to the inner tube, a proximal end fixed to the outer tube, and an interior communicating with the second lumen. A vasodilation catheter comprising the vasodilation catheter according to any one of claims 1 to 8 , wherein the balloon is the catheter balloon according to any one of claims 1 to 8 .

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