JPH07178174A - Basic tube and balloon catheter - Google Patents

Abstract

PURPOSE:To provide a pressure resistivity and a controllability of compliance property in a blow moldable tube body consisting of reinforcing fiber and matrix resin layers, setting a lengthwise extension of the balloon accompanying an expansion of the balloon portion at a specified value. CONSTITUTION:In a blow moldable tube body consisting of reinforcing fiber and matrix resin, the lengthwise extension of the tube is controlled within 20% when molded by blowing. And in a balloon molding obtainable by blow molding in a balloon-like molded body consisting of the reinforced fiber and matrix resin molded by applying blow pressure to the basic tube under a temperature of a given range, the lengthwise extension of the balloon accompanying the expansion of the balloon is controlled to be within 20%. This basic tube has a high strength and does not easily expand in diameter or over a given diameter, so that it is advantageous in manufacturing balloon attaching medical instruments of high safety.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catheter with a balloon which is inserted into a blood vessel to be used for expanding a diameter-reduced portion of the blood vessel.

[0002]

BACKGROUND OF THE INVENTION The present invention percutaneously inserts / expands a balloon catheter into a blood vessel or places it in the ureter or trachea.
Balloon catheters such as catheters for securing a lumen are used in various fields. For example, without surgery
Percutaneous insertion of a catheter into a blood vessel has been actively used in recent years to treat lesions involving blood vessels, and guiding catheters, dilatation catheters, etc. are generally used when performing vasodilation, etc. . Among these, in the balloon catheter, various characteristics are required for the balloon portion according to the state of the lesion, but as a common requirement item,
With respect to the compliance and the pressure resistance, there is a demand for a balloon having high strength and high safety, in which the diameter is less likely to expand beyond a certain diameter.

More specifically, a conventional balloon made of only a thermoplastic resin and having no fiber reinforcement has the following problems.

1. The pressure resistance against expansion pressure is generally low. Particularly, balloons made of a resin used for a soft and highly compliant type generally show lower compressive strength than a balloon having low compliance.

2. For balloons that require even higher compliance, those made of resin alone tend to have higher compliance at higher pressures.
Once ruptured, vascular damage can be increased.

In recent years, from the viewpoint of improving the safety of balloon catheters, there has been a demand for a balloon having a high withstand pressure and a characteristic that the compliance gradually decreases toward the high pressure side. In such a balloon catheter, the direction of fiber reinforcement of the balloon part is shown as one solution. Already British Patent No. 1566
No. 674 proposes balloon reinforcement with a woven structure. The drawback of the balloon reinforced with this simple woven structure is that the woven structure inevitably interlocks the longitudinal and lateral fibers during expansion. Therefore, when the diameter is increased by expanding the balloon, shrinkage occurs in the length direction of the balloon.

[0007] Further, Japanese Patent Publication No. 63-500289 (Applicant, Eyes Medox Thazim) discloses an expansion catheter in which a shaft portion and a balloon portion are integrally braid-reinforced. In this proposal, the angle of the blade is changed between the shaft portion and the balloon portion, and when the pressure exceeds a certain level, the fiber-reinforced portion corresponding to the balloon expands. Although such an integrated mechanism is unique in itself, the performance / functions required for a balloon and those required for a shaft in an actual procedure are completely different from each other. It must be said that there is still a distance to be made into a truly excellent catheter due to the restriction due to aging.

Also from the viewpoint of manufacturing process, after a balloon shape is once formed, the inside is pressed into a lattice shape (woven structure, blade, etc.), a twisted wire shape, a spiral shape or a knitting structure (knit). There were some difficulties such as having to insert the child in advance and finally removing it. For example, in Japanese Examined Patent Publication No. 3-68706 (Applicant Cook, Inc.), after knitting (braiding) under pressure, it is formed as an intermediate layer by squeezing and then dipped in liquid urethane for molding. It is stated that it will be done. In such a balloon molding method, it is undeniable that the effect of fiber reinforcement is diminished in the present situation of balloon development in which the thickness of the balloon is inevitably considerably increased and the wall thickness is being reduced.

Further, in JP-A-2-295566 (Applicant Toray Co., Ltd.), the inner elastic film has a thickness of 250.
The rubber of μm is tied and fixed to each tip of the inner tube and the outer tube with nylon thread. Separately, the tubular knitted material made of composite thread is covered with the banded product with rubber attached and fixed with nylon thread. Then, the excess tubular knit material and rubber are cut off to complete the balloon. However, with this method, it is difficult to obtain a balloon having a uniform film thickness, which may cause a problem in terms of pressure resistance.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a blow-moldable original tube and a fiber-reinforced balloon made from the same, for the purpose of imparting pressure resistance and compliance controllability of the balloon portion. That is, the property of the balloon portion is preferably controlled by fiber reinforcement, and a suitable means therefor is provided.

The present invention is to provide a base tube having blow moldability for manufacturing a type in which a balloon portion used in a catheter of this type is reinforced with fibers. The aim is to provide a highly safe medical device that is unlikely to expand.

[0012]

In order to solve the above-mentioned problems, the original tube for balloon molding of the present invention is a blow-moldable tube body comprising reinforcing fibers having blow moldability and a matrix resin layer. In the balloon obtained by blow molding, the elongation in the lengthwise direction of the balloon caused by the expansion of the balloon is within 20%.

Further, as one structural form of the original tube, first, there can be mentioned one having substantially the following three-layer structure.

1. Inner layer whose innermost layer is made of matrix resin 1. 2. A fiber reinforcing layer in which the intermediate layer is a reinforcing fiber. Outer layer whose outermost layer is made of matrix resin Next, as a structural form close to the above structure, the inner layer and / or outer layer is made extremely thin, or a fiber layer is formed on the inner and / or outer peripheral surface (matrix resin). Those that appear (in close contact with) are also useful depending on the intended use.

Furthermore, the balloon catheter of the present invention is a balloon-shaped molded product made of a reinforcing fiber and a matrix resin, which is molded by blow-pressing the above-mentioned original tube under a certain temperature range. The fiber-reinforced balloon has a longitudinal elongation of 20% or less, which is caused by the expansion of the balloon.

[0016]

The blow-moldable original tube of the present invention has high strength and is less likely to expand beyond a certain diameter, which is advantageous in manufacturing a highly safe balloon-mounted medical device. That is, due to the fiber reinforcement, the balloon portion can be relatively easily expanded (expanded) in a region where the expansion pressure is low, but since the reinforcing fiber extends as the expansion occurs, the balloon diameter gradually conforms to the expansion pressure (increase rate). Is coming down. In addition, the fiber reinforcement increases the pressure resistance (compared to the non-reinforced one).

[0017]

In the production of the original tube of the present invention, a tube having an inner cavity may be used as it is as an inner layer from the beginning, but for example, a copper wire or the like is once coated with an inner layer to form a fiber structure. After applying the outer layer,
The copper wire may be removed, or the outer layer may be formed after removing the copper wire immediately before forming the outer layer.

The inner layer generally comprises a thermoplastic resin layer. Examples of the method for forming the inner layer include extrusion molding of thermoplastic resin, resin coating (melt coating, solution coating, drying, etc.) on a core wire such as a copper wire, or vapor deposition / sputtering on the core wire. The method is raised.

In the present invention, examples of the resin used for the inner layer include polypropylene, polyethylene (particularly low density polyethylene), polyolefin such as ethylene-vinyl acetate copolymer, polyamide elastomer,
Polyester elastomer, polyurethane elastomer, soft polyvinyl chloride, polystyrene elastomer,
Various flexible resins and elastomers such as fluoroelastomers, silicone rubbers and latex rubbers can be used. Among them, polyurethane elastomer, polyamide elastomer, polyester elastomer, and polyolefin elastomer are particularly preferable.

In the above, the polyamide elastomer is, for example, nylon 6, nylon 64, nylon 66,
Nylon 610, Nylon 612, Nylon 46, Nylon 9, Nylon 11, Nylon 12, N-alkoxymethyl modified nylon, hexamethylenediamine-isophthalic acid polymer, various aliphatic compounds such as metaxyloxylcyamine-adipic acid condensation polymer A typical example is a block copolymer having an aromatic polyamide as a hard segment. In addition, a polymer alloy (polymer blend, graft polymerization, random polymerization, etc.) of the polyamide and a resin having high flexibility, or a plasticizer of the polyamide is used. It is a concept that includes those softened by, etc., and also a mixture thereof.

If necessary, various additives such as an alloying agent, a compatibilizing agent, a curing agent, a softening agent, a contrast agent, a stabilizer, and a coloring agent are added to the polyamide elastomer, polyester elastomer, polyurethane elastomer and polyolefin elastomer. You may mix a thing. In this case, it is preferable to use an additive that is difficult to be extracted with a solvent, a drug solution, blood or the like.

The intermediate fiber reinforcing layer is made of a monofilament or a multifilament having a relatively high elongation, and the reinforcing structure can be formed directly on the outer circumference of the original tube or the core wire.

Specific fiber structures include the following.

・ Blade (weave, lattice including set) ・ spiral ・ knit ・ warp (straight, corrugated) ・ A combination of the above-mentioned reinforcing fibers are extreme during blow molding (blow molding temperature) which is the next step It is selected from a group of fibers having properties such as heat shrinkage or insufficient elongation that do not hinder blow molding.

The specific types of fibers that can be used in the present invention are the characteristics and levels required by the intended medical device for fiber-reinforced balloons, as well as the manufacturing process of the fiber-reinforced original tube and the blow molding process into a balloon shape. Needless to say, it is selected by That is, it is important to appropriately combine the indices of mechanical properties such as strength, elongation and yield stress, the indices of temperature properties such as heat shrinkage temperature and softening point, and the balance between the respective constituent components.

In consideration of the above requirements, the optimum one can be selected specifically from the group consisting of the following fibers.

Fiber Resin Classification: i. Fibers that are straight and have (constant) elongation-Elastomer resin (polyamide elastomer, polyester elastomer, polyurethane elastomer, polyolefin elastomer, silicone elastomer,
Fluorine-based elastomers, etc. ・ Polyester resin ・ Polyamide resin ・ Polyolefin resin ・ Engineering resin ・ Regenerated cellulose resin, modified cellulose resin ii. Fibers capable of imparting (structural) elongation depending on the fiber shape Even if the fibers are relatively rigid and have low elongation, they can be used in the present invention by controlling higher-order structural or morphological elements. Fibers capable of imparting (apparent) stretchability: -Fiber stretching treatment category: undrawn yarn, drawn yarn-Fiber morphology category: undrawn yarn, drawn yarn-Other categories: single yarn / composite yarn, wound Crimp,
Uncrimped yarn In the present invention, the pressure resistance and the maximum expanded outer diameter of the balloon can be controlled by the reinforcing structure of the fibers arranged in the plane direction. Further, for the purpose of preventing excessive extension in the length direction of the balloon, it can be controlled by arranging one or more relatively low-expansion yarns in a straight or corrugated shape in the length direction of the original tube. In the present invention, in particular, since the balloon is finally formed into a balloon shape, the state of the warp yarn in the balloon after blowing is maintained by the matrix in a state of being stretched according to the blow ratio. Since the strong elongation property of the yarn in the stretched state can be predicted in advance by measuring the stretch ratio, it can be utilized for designing mechanical properties in the longitudinal and transverse directions as a balloon member.

The outer layer is formed by polymer coating on the tube (or coated core wire) consisting of the inner layer and the fiber-reinforced structure or the fiber-reinforced structure alone. Specific examples of the polymer coating include application / drying of a polymer solution, coating with a polymer solution, vapor deposition, and the like to form an outer layer by permeation of a resin into a fiber structure.

The resin that can be used in the outer layer can basically be selected from those that can be preferably used in the inner layer. However, when the outer layer is melt-coated, it is necessary to avoid those which adversely affect the inner layer and the reinforcing fiber which are already the base. That is, avoid the deformation of the underlying inner layer / reinforcing fibers due to excessive heat shrinkage, and the resin or resin coating conditions that may no longer make sense as the reinforcing fibers melt at the time of melt coating. There is a need.

Since the outer layer is formed by the solution coating method, it has a relatively low viscosity. Therefore, if the impregnation property into the reinforcing fiber portion is good, it is easy to form a relatively thin layer. Can enjoy. Depending on the type of solvent that dissolves the resin, the inner layer that is the base,
Some of them adversely affect the reinforcing fibers, and it is necessary to avoid their use and select a more preferable solvent.

In the present invention, the inner layer, the reinforcing fiber,
Needless to say, it is important to improve the adhesion between the outer layers even in the case of a relatively flexible (softened) reinforcing fiber structure of a flexible resin as in the present invention.
In particular, by improving the adhesion of the fiber surface, the outer surface of the inner layer, and the inner surface of the outer layer, it is important in terms of ensuring stability (durability) during repeated use of the balloon manufactured according to the present invention. Therefore, the impregnation of resin (resin solution) at the time of forming the outer layer is an important factor, and if necessary, measures such as primer treatment and corona treatment to improve the adhesiveness / adhesion can be used to improve performance / function. Can be improved.

The original tube prepared through the above steps can be formed into a balloon shape by blow pressurization in a constant temperature range. However, it is already clear from the above-mentioned configuration of the present invention that the following requirements must be satisfied in blow molding. That is, the features will be described below.

1. 1. The resin and fiber used in the tube of the present invention have blow-moldable properties when used alone or when combined. In addition, the above three components have blow moldability under the same temperature and pressure conditions. 3. In the step of forming and descending each layer one after another, in the subsequent step, do not have an adverse effect (such as excessive heat shrinkage) on the base portion that has already been formed in the previous step. The fiber-reinforced balloon produced according to the present invention has an elongation in the lengthwise direction of the balloon of 20% or less caused by the expansion of the balloon. Therefore, the reinforcing fiber used in the present invention has a reinforcement structure designed to have sufficient elongation so as not to cause the contraction in the length direction, corresponding to the expansion and contraction in the circumferential direction of the intended balloon. To be done.

In the present invention, by covering a part or all of the outer surface of the fiber-reinforced original tube or the balloon after blow molding with a hydrophilic (or water-soluble) polymer substance, the outer surface of the catheter including the balloon is made of blood. Or, when it comes into contact with physiological saline or the like, the friction coefficient is reduced and lubricity is imparted, so that slidability is further improved, and as a result, pushability, followability, kink resistance and safety are further improved. It is possible to preferably perform such high-order surface treatment.

As the hydrophilic polymer, various natural or synthetic polymer substances or their derivatives can be used.

In order to fix the treatment for improving the slidability to the outer surface of part or all of the balloon or the catheter including the joint portion with the balloon, the reactive functional group present on the balloon surface or intentionally introduced is used. It is preferably carried out by covalent bonding. This can provide a continuous lubricious surface.

The composition of the hydrophilic polymer substance and the coating method in the present invention are described in, for example, JP-A-53-1067.
78, U.S. Pat. No. 4,100,309, JP-A-63-2.
Those described in JP-A-59269 and JP-B-1-33181 can be applied.

[0038]

EXAMPLES Specific examples of the present invention will be described below.

[0039]

Example 1 Formation of Inner Layer Thermoplastic polyurethane pellets (Nippon Milactone, P2)
2MR) has a softening point of 56 ° C (measurement method: JIS K720
6)) was melted by an extruder and coated on a copper wire having a diameter of 0.5 mm. The diameter of the coated electric wire was 0.64 mm. The thickness of the (coated) inner layer thus corresponds to 70 mm.

Reinforcing fiber braid Using a braiding machine, 1 fiber for reinforcement (polyurethane yarn, 30 denier, elongation 500%) was applied to this inner layer.
A 6-thread braid was applied.

Formation of Outer Layer The coated copper wire coated with the above blade was coated with the same tetrahydrofuran (THF) solution of polyurethane as the inner layer.

The above copper wire / inner layer / fiber reinforcement layer /
A tube was produced by removing the inner core copper wire from the coated copper wire formed of the outer layer.

[0043]

Example 2 The original tube obtained in Example 1 was put into a blow molding machine for balloon molding and blow molded at 106 ° C. to prepare a blade-reinforced balloon. The prepared balloon was inserted into a commonly used blood vessel or the like to attach a used catheter to form a balloon catheter.

FIG. 1 shows the relationship between the expansion diameter and the expansion pressure when the balloon obtained in Example 2 is expanded. The horizontal axis is the pressure for expanding the balloon, and the vertical axis is the expansion diameter of the balloon. Is.

[0045]

EFFECTS OF THE INVENTION The balloon obtained by blow molding according to the present invention has a high pressure resistance in terms of performance due to the fact that it is provided with a fiber reinforced structure, and does not easily inflate above a certain diameter. In addition to the characteristics, the elongation in the length direction of the balloon caused by the expansion of the balloon is 20%.
Within the range, the dimensional stability is extremely excellent.

Further, a fiber-reinforced original tube is manufactured in advance,
After that, the balloon can be formed by blow molding, so it can be made thinner, and it is promising for application to catheters where there is an increasing demand for thinner diameters. Since it can be molded into, the pressure resistance can be improved.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the expansion diameter and the expansion pressure when the balloon obtained in Example 2 is expanded.

Claims (2)

[Claims] 1. A blow-moldable tube comprising a reinforcing fiber and a matrix resin layer, wherein the elongation in the lengthwise direction of the balloon caused by expansion of the balloon when molded by blow molding is within 20%. The original tube characterized in that 2. A balloon-shaped molded product comprising a reinforcing fiber and a matrix resin, which are molded by blow-pressing the original tube according to claim 1 at a temperature within a certain range, wherein the balloon obtained by blow molding is a balloon. The expansion of the balloon in the longitudinal direction caused by the expansion is 20
% Balloon catheter.