JPH09220285A - Production of wire reinforcing tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wire reinforcing tube which lessens the formation of air bubbles and more particularly the air bubbles invisible to naked eyes. SOLUTION: This wire reinforcing tube is produced by spirally winding a wire on a polyurethane elastomer tubular film formed on an arbor and, further, coating the surface thereof with a soln. of the elastomer, drying the coating and drawing the arbor. In such a case, the wire, after winding, is subjected to a surface treatment with a solvent mixture composed of tetrahydrofuran and cyclohexanone and is coated with the polyurethane elastomer soln.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane elastomer tube reinforced with a spiral wire and having smooth inner and outer surfaces, and more particularly, to a polyurethane elastomer tube having a thin wall and a small spiral pitch of the wire. The tube obtained is particularly useful as a medical tube such as a catheter.

[0002]

2. Description of the Related Art Conventionally, a wire made of a thermoplastic or thermosetting polymer, such as a spiral piano wire or synthetic resin monofilament, is embedded in a tube wall to prevent kink resistance (refraction) and pressure resistance. A tube having a high resistance and crush resistance is known. In particular, as medical and various control tubes, there are known tubes having a thin tube thickness for improving flexibility and transferring a large amount of fluid with a small diameter. As a method for producing such a tube, a wire is spirally wound around a tube-shaped film made of a thermoplastic or thermosetting polymer formed in the shape of a core metal so as to have an affinity with the polymer. There is known a molding method comprising a series of steps of coating a thermoplastic polymer or thermosetting polymer solution in a state of being wet with a solvent having a high property, drying, and crosslinking treatment if necessary (Japanese Patent Laid-Open No. 2004-242242). 62-13891).

[0003]

However, although such a method is effective in preventing the generation of bubbles,
The generation of fine bubbles cannot be sufficiently prevented. That is, according to this method, when coating the polyurethane solution,
Affected by humidity, water is absorbed in the solution, and this water causes foaming due to drying or heating in the crosslinking step,
The bubbles become invisible to the naked eye. By repeating the above steps, bubbles grow and visible bubbles are generated.

This phenomenon is particularly remarkable when the solution viscosity of the polyurene elastomer to be coated is high, but it was difficult to completely remove the bubbles even when using a liquid having a low viscosity.

Further, a method for preventing foaming due to drying at 25 ° C. or lower was tried, but in a wire rod embedding tube for transferring a large amount of fluid with a small diameter, a thin polymer layer is used. Since it takes a long time to dry at 25 ° C or less, the polymer of the tube polymer swells or dissolves remarkably under the influence of the polymer solution covering the wire, and the wire rod bites into the inner surface and is exposed. However, it was not possible to obtain a good wire rod embedding tube because the wire rod pitch was disturbed.

An object of the present invention is to provide a large amount of fluid with a small diameter and a thin tube wall thickness, especially even a reinforced wire embedding tube having a thickness of 0.5 mm or less. It is silky and has no pitch irregularity in the wire rod, and there are very few fine bubbles that are invisible to the naked eye. Especially, the number of bubbles that can be observed with a magnifying glass of 3 times is not visible to the naked eye within 1 cm ² . An object of the present invention is to provide a method for manufacturing a wire rod reinforcing tube in which ten or more wires do not exist.

[0007]

The above object is to spirally wind a wire on a polyurethane elastomer tube-like film formed on a cored bar, and further coat a solution of the elastomer on the wire and dry it. Then, when manufacturing the wire rod reinforcing tube by pulling out the core metal, after winding the wire rod, it is surface-treated with a mixed solvent of tetrahydrofuran and cyclohexanone and coated with the polyurethane elastomer solution. This is accomplished by providing a tube manufacturing method.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The preferred embodiments of the present invention are as follows. A wire material such as a tungsten wire is spirally wound around a tube-shaped film made of a polyurethane elastomer formed in the shape of a core and having a wall thickness of 0.3 mm or less,
Furthermore, a polyurethane elastomer solution is coated on it,
After carrying out forced drying at 40 ° C. to 80 ° C. for 5 minutes to 20 minutes, the core metal is pulled out to manufacture a wire rod reinforcing tube, and after winding a wire rod such as a tungsten wire, tetrahydrofuran and cyclohexanone are added. Is a method for producing a wire rod-reinforcing tube having a wall thickness of 0.5 mm or less, which is surface-treated with the mixed solvent of (1) and is coated with a polyurethane elastomer solution in a state where the tube-shaped film and the tungsten wire are wet with the solvent.

A typical example of the polyurethane elastomer used as the tube-like coating in the present invention is a polyether type or polyester type polyurethane elastomer having an initial tensile resistance of 1 × 10 ² kgf / cm ² or less. To be Since the polyurethane elastomer has high biocompatibility and has an elongation elastic modulus of almost 100%,
Especially suitable for medical tubes such as catheters.
As a tube-shaped film, 0.3 mm or less, especially 0.1
The thin wall thickness is preferably 5 to 0.3 mm, and the tube inner diameter is preferably 1.5 mm to 11.0 mm.

In the present invention, a method of forming a polymer tube-like film on the core metal is a tube formed by extrusion molding.
A typical example is a method of inserting the hook into the core metal.

Next, in the present invention, the wire wound in a spiral shape on the core metal is formed at a high density in order to impart kink resistance in addition to pressure resistance and crush resistance of the tube. Here, as the wire material, the above-mentioned tungsten wire and steel wire are preferably mentioned, but a resin material, for example, a synthetic resin monofilament or the like can also be used.

In the present invention, it is important to wind the wire around the tube-shaped film and then treat the surface with a mixed solvent of tetrahydrofuran and cyclohexanone. By treating with this mixed solvent, it is possible to expel bubbles that are difficult to remove at the boundary surface, and further it is possible to prevent foaming of water in the drying step after the treatment, especially in the drying step at high temperature. The blending ratio of each component of the mixed solvent is tetrahydrofuran: cyclohexanone = 4 to 5: 6 to 5
(Weight ratio) is preferable, and optimally 1: 1 (weight ratio).

After the treatment with the mixed solvent, a polyurethane elastomer solution is coated. As the polyurethane elastomer, the same polyurethane elastomer as that used for the tube-shaped film can be used. It is preferable to use the same kind of these polyurethane elastomers, but it is also possible to use different kinds of polyurethane elastomers.

As the polyurethane elastomer solution,
A polyurethane elastomer dissolved in a simple solvent such as tetrahydrofuran or a mixed solvent such as tetrahydrofuran and cyclohexanone is used. Examples of the method for coating the polyurethane elastomer solution include a coating method, a spray method and a dipping method.

By coating these polyurethane elastomer solutions, flexibility and chemical resistance can be imparted.

Next, the polyurethane elastomer solution is coated and then dried. Drying conditions are 40-80 ° C, especially 4
It is preferable to perform forced drying (air drying) at 0 to 60 ° C. for 5 to 20 minutes. By slowing the drying speed,
The polyurethane elastomer solution adheres evenly to the entire wire reinforcement tube and flows down to form a smooth surface.

The thickness of the polyurethane elastomer coating thus obtained is less than 0.3 mm after drying, especially less than 0.
It is preferably 2 mm or less. The lower limit is preferably 0.05 mm or more, more preferably 0.1 mm or more.

After drying, by pulling out the core metal,
The tube of the present invention is obtained. Examples of the core metal used here include a Teflon-coated iron round bar.

[0019] The wire rod reinforcement tue obtained by the present invention.
A tube, especially a thin-walled small-diameter wire-reinforced tube, has excellent transparency, flexibility, pressure resistance, and kink resistance, and is a smooth tube. Therefore, a catheter, an endotracheal tube, etc. Especially suitable for medical tubes.

The present invention will be further described with reference to the following examples.

EXAMPLES Polyether-based aliphatic polyurethane elastomers having an initial tensile resistance of 30 kgf / cm ² (shore)
Hardness (A) 80) with an ordinary extruder 4.0m inside diameter
After extruding a tube of m and a wall thickness of 0.15 mm and inserting the tube into a Teflon-coated round bar-shaped core metal,
Tungsten wire with a diameter of 0.1 mm on a small lathe
Was wound at a pitch of 0.2 mm.

Then, the wire-wound tube was immersed in a mixed solvent of tetrahydrofuran and cyclohexanone at a ratio of 1: 1 (weight ratio) at a speed of 200 mm / sec, left for 5 seconds, and then taken out. After confirming that and were sufficiently wet, promptly, in a solution prepared by mixing 5% by weight of polyurethane elastomer with tetrahydrofuran and cyclohexanone in a ratio of 1: 1 (weight ratio), 200 mm /
It was dipped at a speed of sec, left for 5 seconds to coat the polyurethane elastomer solution, and then taken out.

Next, it was placed in a drier in which the atmospheric temperature was adjusted to 70 ° C. by hot air, the above-mentioned polyurethane solution-coated tube was left vertically, and was dried for 10 minutes while allowing excess polyurethane solution to flow down, and then in the vertical direction. Was coated with a uniform layer of polyurethane elastomer.

Further, in order to increase the thickness of the coating layer, after taking out from the dryer and cooling to room temperature, the same coating operation is repeated 10 times with the above urethane elastomer solution, and the wire having a coating thickness of 0.15 mm is repeated. A reinforcing tube was obtained.

A wire reinforcing tube obtained by demolding a core metal
The tube has a smooth surface, excellent transparency, and there are no more than 10 invisible bubbles in 1 cm ² inside the tube wall.
It had excellent pressure resistance and kink resistance.

In order to carry out Comparative Examples 1 to 4, the solvents shown in Tables 1 and 2 were used in place of the mixed solvent of Example 1, and the same procedure as in Example 1 was followed to manufacture thin-walled small-diameter wire-reinforced tubes. did. Solvents used: Toluene (boiling point 111 ° C), Tetrahydrofuran (boiling point 66 ° C), Cyclohexanone (boiling point 156 ° C)

The above results are shown in Tables 1 and 2, and it can be seen that the tube obtained by the method of the present invention produces few bubbles even when dried at a high temperature.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

According to the method of the present invention, bubbles which are invisible to the naked eye but can be observed by using a 3 × magnifying glass are 1 cm.
It is possible to reduce the number to 10 or less in ² and it is possible to obtain a tube in which auxiliary wires are embedded at a narrow pitch. The tube obtained by the method of the present invention is
It has flexibility, kink resistance, and pressure resistance, and also has transparency and surface smoothness.

Claims (1)

[Claims] 1. A wire rod is spirally wound around a polyurethane elastomer tube film formed on a cored bar, and a solution of the elastomer is further coated on the wire rod and dried.
When manufacturing the wire rod reinforcing tube by pulling out the core metal, after winding the wire rod, it is surface-treated with a mixed solvent of tetrahydrofuran and cyclohexanone and coated with the polyurethane elastomer solution. Manufacturing method of bu.