JP2000325464A - Medical catheter containing inorganic crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a baloon wherein the pressure-resistance, dimensional stability and flexibility are controlled by using an inorganic crystalline composite material wherein an inorganic crystal is contained in a polymer. SOLUTION: When a medical catheter such as a baloon catheter is manufactured, an inorganic crystalline composite material wherein an inorganic crystal is contained in a polymer is used. As the inorganic crystal to be used, a layer crystal is preferable. Especially, an inorganic crystalline composite material obtained by ion-exchanging a layer crystal by an intercalation, e.g. an inorganic crystalline composite material of montmorillonite and polyamide, inorganic crystals are monodispersed by a nano-order of 0.5 to 100 nm. In this case, by the increase of the total surface area and the reduction of a distance between particles, a mutual reaction due to an ionic bond, or the like, between the inorganic crystal and the polymer particle, and in addition, between inorganic crystals with each other, is increased, and an excellent reinforcing effect can be obtained. For this reason, an ion exchanging layer crystal wherein the intercalation can be easily performed, and inorganic crystals can be monodispersed, especially, a silicate, or the like, is preferably used as the inorganic crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a medical catheter such as a catheter or a balloon catheter having a balloon.

[0002]

2. Description of the Related Art Balloon catheters having balloons are becoming more and more useful in medical treatment and are being actively improved to improve their functions.

[0003] As a treatment method using a balloon catheter, percutaneous coronary angioplasty (PTCA) for expanding a stenotic portion of a blood vessel such as a coronary artery or percutaneous angioplasty (PTA) for expanding a stenotic portion such as a peripheral blood vessel are used. Also, there is aortic balloon pumping (IABP).

[0004] In a balloon catheter of PTCA or PTA, trackability (followability) is achieved at a shaft portion.
, Pushability (force transmission) and small diameter are required, and high flexibility and low profile (thin film) are required as well as high pressure resistance and non-compliance (dimensional stability) in the balloon portion. .

The materials of the polymer include acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene-acrylate copolymer, chlorinated polyurethane, ethylene propylene rubber, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer. Coalesce, high impact polystyrene, ionomer, methacrylate-butadiene-styrene copolymer, acrylonitrile butadiene rubber, polyamide, polybutadiene, polybutylene terephthalate, polycarbonate, polyetherimide, polyethylene terephthalate, polymethyl methacrylate, polyacetal, polyphenylene ether,
Examples include polyphenylene sulfide, polyurethane, polyvinyl chloride, styrene-acrylonitrile copolymer, styrene-butadiene rubber, silicone resin, styrene-maleic anhydride copolymer, polystyrene, polyethylene, polypropylene, and polyimide.

As an example of the material used for the balloon portion, first, polyamide (nylon) is given. Nylon is classified based on the number of carbon atoms in one unit of its molecular structure, and has different properties depending on the length of the carbon chain. For example, nylon 12
In the case of the above, the melting point is 179 ° C., and the nylon has properties that are more flexible than other nylons. A balloon made of this nylon 12 is a balloon having flexibility but inferior in pressure resistance and dimensional stability as compared with other nylons.
Further, in the case of nylon 66, the melting point is as high as 223 ° C., which has a higher elastic modulus than other nylons, but the balloon has poor flexibility.

Conventional techniques for compensating for these drawbacks include JP-A-5-95996 and JP-A-9-509860. The former technology is a balloon in which an aliphatic-aromatic polyamide is used as a base polymer instead of an aliphatic polyamide, and a polymer alloy of an aliphatic polyamide is used as a hard segment.

The latter technique is a balloon made of a polyamide elastomer obtained by copolymerizing a polyamide with a polyether as a soft segment.

[0009]

However, the prior art has not been able to obtain a balloon having sufficiently controlled tensile strength and elongation which affect pressure resistance and dimensional stability.

[0010] Specifically, an aliphatic-
In the prior art in which an aromatic polyamide is selected and an aliphatic polyamide having a short carbon chain is polymer-alloyed to further improve dimensional stability and strength characteristics, pressure resistance and dimensional characteristics are increased due to having an aromatic ring in the main chain. Although stability is improved, it is not as good as a polyethylene terephthalate (PET) balloon, and is inferior to aliphatic polyamide in flexibility.

Furthermore, in the above prior art, an aliphatic polyamide is alloyed as a hard segment. However, if the blending ratio is too high, the properties of the base polymer will be greatly impaired. Since it is a polymer, there is a problem that a sufficient reinforcing effect cannot be obtained.

In the prior art, a polyimide having a relatively short carbon chain is selected as a base polymer, and a flexible balloon is obtained by copolymerizing a polyether to impart flexibility to the base polymer. However, it is impossible to improve the pressure resistance and the dimensional stability beyond the properties of the base polymer. That is, it acts only in a direction that impairs the properties of the base polymer, polyamide, and is inferior to PET balloons in pressure resistance and dimensional stability.

Further, if the blending ratio of the soft segment is excessively increased, the pressure resistance and the dimensional stability rapidly deteriorate. There is a problem that dimensional stability cannot be obtained.

[0014]

SUMMARY OF THE INVENTION The problems associated with such a balloon portion are solved according to the present invention by a medical catheter comprising an inorganic crystal composite material comprising inorganic crystals in a polymer.

More specifically, the effect of the present invention is more easily exhibited when the inorganic crystal is a layered crystal.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION First, inorganic crystals used in the present invention are shown in Table 1 by classifying them by composition. Of the inorganic crystals, Table 2 shows layered crystals having a layered structure, Table 3 shows ion-exchangeable layered crystals containing ions between layers, and Table 4 shows other layered crystals forming interlayer compounds. A representative inorganic crystal is shown as an example.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

[Table 4]

Although there are various shapes and sizes of inorganic crystals, it is preferable to use an inorganic crystal composite material containing the inorganic crystals shown in Tables 2, 3 and 4 for the balloon portion.

In particular, an inorganic crystal composite material obtained by ion exchange (organization) of the layered crystal by intercalation,
For example, in an inorganic crystal composite material of montmorillonite and polyamide, the inorganic crystal is monodispersed in the nano order of 0.5 to 100 nanometers. Since the interaction between molecules and inorganic crystals due to ionic bonds and the like is increased and an excellent reinforcing effect is obtained, an ion-exchange layered crystal in which inorganic crystals can be easily intercalated and inorganic crystals are monodispersed, Acid salts and the like are more preferable as the inorganic crystal used in the present invention.

The upper limit of the inorganic crystal content of the inorganic crystal composite material varies depending on the type of the base polymer and the combination of the inorganic crystals to be contained. FIG. 1 shows the relationship between the inorganic crystal content and the tensile strength when a polyamide elastomer is used as the polymer and zeolite is used as the inorganic crystal. In this case, about 60% of the content of the inorganic crystal in the polymer is the upper limit in terms of the tensile strength reinforcement, and if it is contained more than that, the reinforcing effect is hardly improved, and the tensile strength depends on the inorganic crystal to be contained. May decrease. In the case of a shaft application, when forming by a shaft forming method, for example, extrusion forming, 40% is generally a forming limit. However, in the forming by dipping, the shaft can be formed at 80%.

Although the upper limit of the reinforcing effect is generally about 60% in the content of the inorganic crystal in the polymer, the upper limit of the content is not restricted by this, and the inorganic crystal may be contained by 60% or more. In addition, it is preferable from the viewpoint of cost and safety that the content of the inorganic crystal be small within a range satisfying the target tensile strength and elongation. Therefore, although the lower limit of the minimum content of the inorganic crystal is not limited, the content of the inorganic crystal is usually 1% or more, preferably 2% or more. If the content of the inorganic crystal is less than 1%, the effect of the present invention on the tensile strength tends to be insufficient.

[0025]

【Figure 1】

In a balloon application, unlike a shaft, it needs to be movable because it has a small thickness and is repeatedly expanded and contracted by a medical procedure. Therefore,
The upper limit of the inorganic crystal content of the inorganic crystal composite material is generally about 30%. However,
Although 30% is the upper limit in terms of mobility, the upper limit of the content is not limited by this, and 30% or more of inorganic crystal may be contained. In addition, the target tensile strength,
It is preferable in terms of cost and safety that the content of the inorganic crystal be small within the range where the elongation is satisfied.

The lower limit of the inorganic crystal content of the inorganic crystal composite material varies depending on the combination of the base polymer and the inorganic crystal to be contained, but the content and the reinforcing effect are generally in a proportional relationship as shown in FIG. And the effect of reinforcement starts to be obtained even from a small amount.

For example, in the case of an inorganic crystal composite material using a silicate, the tensile strength and the elongation can be generally achieved within the range of 5 to 15%.

For example, when obtaining a non-compliant balloon having high pressure resistance and excellent dimensional stability, an inorganic crystal composite material in which inorganic crystals are monodispersed in a polymer which is advantageous in pressure resistance and dimensional stability is used. For example, if a balloon is made using an inorganic crystal composite material (PA66-S) in which ten percent or more of sepiolite is contained in nylon 66, a balloon having excellent pressure resistance and dimensional stability due to the reinforcing effect of the inorganic crystal. Can be obtained.

Similarly, when obtaining a balloon with improved tensile strength while maintaining elongation and flexibility, an inorganic material prepared by selecting a polymer having sufficient flexibility and an inorganic crystal having a small decrease in elongation due to its inclusion is selected. Using crystalline composite materials,
For example, a nylon 12 elastomer-based inorganic crystal composite material (TPEPA1) containing several percent of hectorite in a composition ratio in which the blending ratio of soft segments is increased in nylon 12 (TPEPA1)
If 2-H) is used to form a balloon, a balloon with improved tensile strength can be obtained while maintaining elongation and flexibility.

Further, the expansion pressure of the balloon and the behavior of the dimensional change of the balloon by the combination of the inorganic crystal composite material and the stretching conditions at the time of balloon molding (compliant characteristics)
It is also possible to obtain a balloon in which is controlled.

Specifically, the dimensional stability is intentionally lowered by lowering the draw ratio at the time of making the balloon. In addition, the dimensional change is adjusted to the compliant characteristics of a general compliant balloon by adjusting the selection of the inorganic crystal, the blending ratio, and the like. For example, the state in which the stent is fully oriented at the final diameter using the stent (stretching limit) ) Can be realized.

Further, from the same concept, balloons having various compliant characteristics from non-compliant balloons to compliant balloons can be designed with inorganic crystal composite materials.

As a method of synthesizing the inorganic crystal composite material, a method of melt-kneading and containing, for example, a method of kneading with a twin-screw extruder or a method of kneading with a plastmill, or a method of containing inorganic crystals in the reaction process , For example, In-S
Itu filler formation method (sol-gel method), In-Sit
There are, for example, a u-polymerization method and a method of dispersing a polymer and an inorganic crystal in a solvent system. A method suitable for dispersing the inorganic crystal may be selected and used.

As a method for facilitating the dispersibility of the inorganic crystal, a method of performing silane treatment, a method of using a coupling agent, and a method of intercalation (intercalation or deintercalation), for example, After the monomer insertion, a polymerization method or a polymer insertion method may be selected and used. In particular, in the case of an ion-exchange layered crystal, the use of intercalation provides an inorganic crystal composite material having a good reinforcing effect in which nano-order inorganic crystals are monodispersed.

The method of synthesizing an inorganic crystal composite material using a polyamide and an ion-exchange layered crystal will be described with reference to an example. Intermediation of montmorillonite with ε-caprolactam, a starting material for nylon, and 1-caprolactam
By intercalating a monomer such as 2-aminolauric acid (ALA) and performing the reaction with the organic crystallized inorganic crystal, the inorganic crystal is monodispersed and an inorganic crystal composite material having a good reinforcing effect can be obtained. .

In the intercalation, the ion exchange capacity of the ion-exchangeable layered crystal is suitably 20 to 200 meq / 100 g, for example, smectite is 60 to 120 meq / 100 g, and vermiculite is 100 to 100 meq / 100 g. 165 meq / 100 g. These can be ion-exchanged (organized) with ionized ammonium ions only by contact with an aqueous solution of n-alkylamine hydrochloride.

For inorganic crystals having a high charge density and a strong bonding force between layers, for example, muscovite having a charge density of 1.0 is reacted with a barium chloride solution at 120 ° C. to exchange ions. For example, the pretreatment may be selected according to the characteristics and properties of each layered crystal, and organic treatment may be performed.

Even in the case of a layered crystal having no ion between layers, for example, a method of reacting n-butyllithium in a hexane solution, or a method of reducing a crystal layer using a strong reducing agent and intercalating alkali ions. And the like, and a method suitable for each layered crystal, such as a method for simultaneously performing the above, may be selected to form an ion-exchangeable layered crystal or to make it organic.

Subsequently, the polymer used in the present invention may be, for example, an aliphatic polyamide, an aliphatic-aromatic polyamide, a polyamide elastomer, a soft polyamide, or an amorphous polyamide.

The above-mentioned polymer may be a polyamide-based blend composed of two or more kinds of polyamides, a polyamide-based polymer alloy, a polyamide-based molecular composite, or a copolymerized polyamide.

As a further supplement, a polymer alloy is
For example, nylon / vinyl polymer alloys, nylon / polyolefin alloys, nylon / polyphenylene oxide (PPO) alloys, amorphous nylon alloys, nylon / polyester alloys, nylon /
Shows nylon alloys.

The molecular composite is, for example, nylon / p-phenylene terephthalate (PP
TA).

The term "copolyamide" refers to a copolymer of two or more nylon salts, for example, nylon 6 (PA
6), nylon 66 (PA66), nylon 610 (P
A610), nylon 12 (PA12), nylon 69
(PA69), random copolymerization of a combination of at least two or more kinds of nylon salts such as nylon 612 (PA612) and combinations thereof,
And isomorphous substituted copolymers such as caprolactam / aminomethylbenzoic acid and caprolactam / 4-aminomethylcyclohexacarboxylic acid.

The polyamide elastomer used in the present invention is a polyetheramide structure in the soft segment, for example, polytetramethylene ether glycol (PTMG) or polypropylene glycol (PP
G), a polyethylene glycol (PEG), an aliphatic polyether diol, and the like, and a copolymer using a polyesteramide structure, for example, an aliphatic polyester.

The soft polyamide refers to a polyamide modified with a plasticizer such as aromatic sulfonic acid amide, p-oxybenzoic acid ester, or N-alkyltoluenesulfonic acid amide.

The non-crystalline polyamide refers to, for example, transparent nylon obtained from the reaction of diphenylmethane diisocyanate with adipic acid, azelaic acid and isophthalic acid.

According to the present invention, a balloon or a shaft is prepared by using the inorganic crystal composite material synthesized by mixing the various inorganic crystals and various polymers shown above at various compounding ratios and by a content method suitable for them. Thus, it has been found that a balloon or shaft having performance and characteristics that cannot be achieved by extension of the conventional technology is obtained.

EXAMPLES Example 1 Montmorillonite was dispersed in a mixed solution of an acidic aqueous solution and 12-aminolauric acid to form a mixture.
After heating to 0 ° C. and stirring for 2 hours, montmorillonite was obtained by washing with water and organizing. Subsequently, 12-aminolauric acid was added, and a polyamide 12 composite material (PA12-M5) containing 5% of montmorillonite was obtained by a condensation reaction.

A film was prepared from PA12-M5 using a uniaxial extruder, and a biaxially stretched sample (dummy balloon) was prepared. The stretching conditions were four times in the machine direction (MD) and four times in the width direction (TD) by simultaneous biaxial stretching. The tensile strength of the dummy balloon was 1578 kg / cm ² . In addition, as shown in FIG. 2 showing the tensile stress-strain curve, it was confirmed that non-compliance characteristics with excellent dimensional stability were exhibited.

(Example 2) Polyamide 12 elastomer composite material containing 3% of montmorillonite (TPEPA12-M3) by adding organically treated montmorillonite, lauryl lactam, PTMG and dodecane diacid to react and condense under the lactam ring opening condition. ) Got.

A film was prepared from TPEPA12-M3 using a uniaxial extruder and biaxially stretched to prepare a sample for evaluation (dummy balloon). The stretching conditions were 4 times for MD and 4 times for TD, and simultaneous biaxial stretching was performed. The tensile strength of the dummy balloon is 1200 kg / cm
^{Was 2} . Further, as shown in FIG. 2, the tensile stress-strain curve was confirmed to exhibit compliant characteristics.

(Example 3) Polyamide 12 elastomer composite material (TPEPA12-M5) containing 5% of montmorillonite by addition of organically treated montmorillonite, lauryl lactam, PTMG and dodecane diacid under a lactam ring opening condition and condensation reaction was added. ) Got.

A film was prepared from TPEPA12-M5 using a uniaxial extruder, and biaxially stretched to prepare a sample for evaluation (dummy balloon). The stretching conditions were 3.5 times MD and 2.5 times TD, and simultaneous biaxial stretching. The tensile strength of the dummy balloon is 1250k
g / cm ² . In addition, as shown in FIG. 2, the tensile stress-strain curve was confirmed to exhibit characteristics that shift from compliant characteristics to non-compliant characteristics.

(Example 4) Synthetic mica, saponite, hectorite and zepiolite were used for polyamide 6 composite materials (PA6-ME, PA6-SP, PA6-HC, PA
6-S5, PA6-S10) were synthesized.

Table 5 collectively shows the tensile strength and elongation. As a result, an improvement in tensile strength of 1.3 to 1.8 times that of non-containing PA6 was confirmed. It was also confirmed that the elongation could be changed by selecting the inorganic crystal. In addition, the tensile strength shows the value of the dummy balloon obtained by simultaneous biaxial stretching, and the elongation describes the resin properties before stretching, respectively.

[0056]

[Table 5]

Example 5 Polyamide 6 composite materials (PA6-5C, PA6-10) were prepared by changing the blending amount of silica.
C, PA6-15C, PA6-20C, PA6-25
C, PA6-30C).

Table 6 collectively shows the tensile strength and elongation. As a result, an improvement in tensile strength of 1.3 to 3 times that of non-containing PA6 was confirmed. In addition, the tensile strength shows the value of the dummy balloon obtained by simultaneous biaxial stretching, and the elongation describes the resin characteristics before stretching. For PA6-15C, balloons were prepared and compliant characteristics were examined. The results are shown in FIG. 3, and it was confirmed that the non-compliance characteristics with extremely excellent dimensional stability were exhibited.

[0059]

[Table 6]

[0060]

According to the prior art of polymerizing an aliphatic polyamide into an aliphatic-aromatic polyamide to improve dimensional stability and strength properties, the flexibility is inferior to that of the aliphatic polyamide, and the organic polymer is not used. Due to the hard segment, the reinforcing effect is small, and if the mixing ratio is too high, there is a problem that the properties of the base polymer are significantly impaired. In the present invention, a high reinforcing effect can be obtained because an inorganic crystal having much higher rigidity is used than a hard segment made of an organic polymer.

In the prior art in which a polyether is copolymerized in order to impart flexibility to an aliphatic polyimide, flexibility can be added, but pressure resistance and dimensional stability cannot be improved. If the number of soft segments is increased too much to improve the flexibility, there is a problem that the pressure resistance and dimensional stability required by the balloon cannot be obtained. In the present invention, a balloon using an inorganic crystal composite material of a polyamide elastomer composed of a combination of a resin having sufficient flexibility and an inorganic crystal having a small decrease in elongation due to the content, while maintaining flexibility compared to a conventional balloon. 1.3-
3.0 times, the tensile strength is improved.

In particular, an inorganic crystal composite material containing an inorganic crystal that has been made organic by intercalation has a high reinforcing effect and is 1.3 to 3 times higher than a polyamide balloon containing no inorganic crystal (prior art balloon). The tensile strength is improved by a factor of 0, and the extension can be maintained by selecting an inorganic crystal.

That is, in the present invention, various inorganic crystals and various polymers are mixed at various compounding ratios, and a balloon or a shaft is prepared by using an inorganic crystal composite material synthesized by a content method suitable for them. Balloons and shafts having tensile strength and elongation characteristics that cannot be achieved by extension of the conventional technology can be obtained. In addition, in the case of a balloon, not only is a balloon having controlled pressure resistance, dimensional stability, and flexibility controlled, but also the expansion pressure of the balloon and the behavior of dimensional change of the balloon (compliant characteristics) are determined by the stretching conditions during balloon molding. It is also possible to obtain a controlled balloon.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between an inorganic crystal content and a tensile strength according to the present invention.

FIG. 2 is a graph showing tensile stress-strain curves of Examples 1 to 3.

FIG. 3 is a graph relating to compliant characteristics of Example 5.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Noriyuki Suzuki 5-32-504 F Torikai Nishi, Settsu-shi, Osaka F-term (reference) 4C081 AC08 AC10 BB07 BB08 BC02 CA021 CA031 CA041 CA052 CA081 CA122 CA131 CA161 CA181 CA201 CA211 CA231 CA232 CA251 CA281 CB051 CC03 CE09 CF112 CF132 CF142 CF152 CF162 CF21 CF22 CG01 DA03 DC12 DC13 EA02 EA03

Claims (3)

[Claims] 1. A medical catheter comprising an inorganic crystal composite material containing an inorganic crystal in a polymer. 2. The medical catheter according to claim 1, wherein the inorganic crystal is a layered crystal. 3. The medical catheter according to claim 1, wherein the medical catheter is a balloon catheter having a balloon.