JP2000051345A - Indwelling catheter made of polyurethane resin containing plural polyglycols different in molecular weight - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an indwelling catheter which has rigidity in piercing and flexibility after indwelling in the blood equal to those of an indwelling catheter made of fluororesin, and shows lowering behavior of elastic modulus optimum for the indwelling operation, and which is excellent in kink resistance. SOLUTION: This indwelling catheter 6 is made of polyurethane resin containing plural polyglycols different in molecular weight and has a dynamic storage elastic modulus of 1 GPa or more in the dry state at 25 deg.C and a lowering rate of the dynamic storage elastic modulus when the time (t) passes while the dry state at 25 deg.C is changed to the humid state at 37 deg.C is under 60% in the lapse of 20 sec, and 60% or more in the lapse of 1 min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indwelling catheter, and more particularly to an indwelling catheter which is indwelled in a blood vessel for the purpose of infusion of a liquid or a drug solution into a body, blood transfusion, collection of blood and monitoring of hemodynamics. .

[0002]

2. Description of the Related Art An indwelling needle used for infusion or blood transfusion is a catheter formed of plastic or the like which can be indwelled in a blood vessel. It is used by connecting a tube extending from the container. Some indwelling needles are integrally formed by inserting an inner needle having a pointed end made of metal or the like. This type of indwelling needle is used in the same manner as described above, after piercing the catheter into the blood vessel together with the inner needle, removing the inner needle from the indwelling needle.

In order to achieve the main purpose of an indwelling needle, ie, infusion of an infusion solution or a drug solution, it is important to secure a flow path for an indwelled catheter. Therefore, a catheter having excellent kink resistance is required. I have. Further, the operability at the time of puncturing and the interaction between the vascular wall at the time of puncturing and after placement are affected by the mechanical properties of the catheter. Therefore, it is desirable that the catheter be sufficiently stiff at the time of puncturing and be flexible after placement.

Conventionally, fluororesins such as polytetrafluoroethylene and ethylene-tetrafluoroethylene copolymer have been mainly used as the material for indwelling catheters. Fluororesin catheters are hard and stiff at the time of puncture, so they are excellent in operability and easy to secure blood vessels. However, these fluororesin catheters are not sufficiently flexible after placement of the blood vessel, and may damage the blood vessel wall. In addition, the kink resistance is not sufficient, and there is a possibility that it may hinder the securing of an infusion channel.

In view of such circumstances, recently, a polyurethane resin comprising a hard segment and a soft segment, and the soft segment is made of polyether has been used as a catheter material for an indwelling needle. Japanese Patent Publication No. 8-11129 discloses a catheter tube that uses a hydrophilic polyether polyurethane resin to be softened in a blood vessel, and controls the balance between rigidity at the time of catheter insertion and flexibility after indwelling the blood vessel. A method for doing so is also described. However, this catheter has a problem that the kink resistance is poor. An indwelling catheter made of a polyether polyurethane resin has a drawback that even if it becomes flexible after being indwelled, sufficient kink resistance is not exhibited.If the catheter is hardened for operability at the time of puncturing, the kink resistance is further impaired. I will be.

Further, by adjusting the molecular weight of the soft segment, it is also possible to improve the amount of change in elastic modulus and the kink resistance. However, the molecular weight of the soft segment is 500
When using only a polyurethane resin using polyglycol at ~ 1500, from a dry state of 25 ° C to 37 ° C
Although the elastic modulus greatly changes due to the change to the wet state, the kink resistance is not good, or even if it is good, there is a drawback that the original shape is not restored once kinked. On the other hand, a polyurethane resin using a polyglycol having a molecular weight of 1500 to 3000 has good kink resistance, but the elastic modulus does not largely change due to a change from a dry state at 25 ° C to a wet state at 37 ° C. When a polyurethane resin containing a soft segment having substantially a single molecular weight is used as described above, it is impossible to satisfy both the desired change in elastic modulus and kink resistance.

Japanese Patent No. 2723190 describes an indwelling needle made of a shape memory resin. The catheter of this indwelling needle is hard when the blood vessel is inserted, and becomes flexible after the indwelling of the blood vessel.However, since the change speed is too fast, the catheter becomes soft during the indwelling operation, which hinders the puncturing operation. I will.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to have the same rigidity as a fluororesin catheter at the time of insertion into a blood vessel, but to reduce the damage to the blood vessel by softening after being placed in the blood vessel. Another object of the present invention is to provide an indwelling catheter exhibiting a behavior of lowering the elastic modulus suitable for an indwelling operation and having excellent kink resistance.

[0009]

Means for Solving the Problems In view of the above object, as a result of intensive studies, the present inventors have found that the indwelling catheter has good rigidity (operability) at the time of puncturing, and that after indwelling, the indwelling catheter becomes flexible and damages blood vessels. In order to be able to suppress this, it is important to adjust the rate of decrease in the modulus of elasticity when placed in a wet state at 37 ° C. from a dry state at room temperature. Too much time was taken, which could cause vascular damage after placement, and conversely, if the elastic modulus decreased too quickly, it became flexible during the placement operation, which made it difficult to puncture.

As a result of studying the softening performance of the polyurethane resin based on this finding, it was found that the degree of softening of the polyurethane resin generally greatly depends on the crystallinity of the polyglycol contained therein. When a polyglycol having a low molecular weight is present in the polymer chain, the crystallinity of the polyurethane resin does not easily increase, and the melting of the crystal is promoted by the temperature rise. Therefore, the rate of softening of the polyurethane resin with an increase in temperature increases.

By the way, polymers having similar molecular structures are generally compatible with each other, so that when they are blended, they show additive properties in physical properties. Therefore, polyurethane resins containing polyglycols of different molecular weights are expected to exhibit their average physical properties. However, according to the study by the present inventors, it was found that the additive property of the physical property was not satisfied. Therefore, as a result of diligent research, even if polyglycol, which alone produces a polyurethane resin with inferior properties, when a polyurethane resin is produced by combining a plurality of them, it has almost the same rigidity as a fluororesin catheter when inserted into a blood vessel, The present inventors have found that an indwelling catheter which can be softened after indwelling to reduce damage to a blood vessel, exhibits an elastic modulus lowering behavior suitable for indwelling operation, and has excellent kink resistance can be obtained, and arrived at the present invention.

That is, the indwelling catheter according to the first aspect of the present invention is characterized by being formed of one polyurethane resin containing a plurality of polyglycols having different molecular weights.

The indwelling catheter according to the second aspect of the present invention is made of one polyurethane resin containing a plurality of polyglycols having different molecular weights, and has a dynamic storage modulus in a dry state at 25 ° C. of 1 GPa or more. the reduction rate E _p of dynamic storage modulus when a lapse of time t in the wet state 37 ° C. from the dry state of 25 ° C., the following formula: E _p = [(E0-Et) / (E0 -E30 )] × 100
% (Where E0 is the dynamic storage elastic modulus in a dry state at 25 ° C., E30 is the dynamic storage elastic modulus after 30 minutes in a wet state at 37 ° C., and Et is the wet storage elasticity at 37 ° C.) a dynamic storage modulus when t has elapsed when expressed by.), reduction rate E _p of the dynamic storage modulus at 20 seconds after the 6
Less than 0%, the reduction ratio E _p at one minute is equal to or less than 60%.

In any of the embodiments, the polyurethane resin preferably comprises a diisocyanate, a diol-based chain extender and a plurality of polyglycols having different molecular weights. The plurality of polyglycols includes a first polyglycol having a molecular weight of 500 to 1500, and a second polyglycol having a molecular weight of 1500 to 3000,
The difference between the molecular weight of the first polyglycol and the molecular weight of the second polyglycol is preferably 500 or more. The weight ratio between the first polyglycol and the second polyglycol is preferably from 8: 2 to 2: 8. Further, the polyurethane resin is a reaction product of 4,4′-diphenylmethane diisocyanate, 1,4-butanediol and a plurality of polycaprolactone glycols having different molecular weights, and preferably has a Shore hardness of 60 D or more.

The indwelling catheter according to the preferred embodiment of the present invention exhibits a kink resistance of 10 mm or more in both a dry state at 25 ° C. and a wet state at 37 ° C. Its initial elastic modulus is 50 kgf / mm ² or more in a dry state at 25 ° C., and 25 kgf / mm ^{2 in} 5 minutes in a wet state at 37 ° C.
mm ² or less.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In order to maximize flexibility by changing from a dry state at 25 ° C. to a wet state at 37 ° C., the molecular weight of at least one polyglycol constituting the polyurethane resin is 1500 or less, preferably 500-1500
And If the molecular weight of the polyglycol is less than 500, it is difficult to exhibit the function as a segmented polyurethane resin, and the properties of the polyurethane resin depend exclusively on the performance of the polyglycol having a large molecular weight. By including the second polyglycol having a molecular weight of 1500 to 3000, the kink resistance of the polyurethane resin is improved. The difference between the molecular weight of the first polyglycol and the molecular weight of the second polyglycol is preferably 500 or more, more preferably 1000 or more. If the difference between the molecular weights of the polyglycols is less than 500, the effect of including a plurality of polyglycols having different molecular weights becomes insufficient. Also,
Preferably, the weight ratio of the first polyglycol to the second polyglycol is from 8: 2 to 2: 8. When the weight ratio is out of this range, the effect of using polyglycols having different molecular weights becomes insufficient. In addition, "molecular weight" means a number average molecular weight. The molecular weight distribution of the polyglycol used in the present invention is narrow.

The physical properties of the polyurethane resin depend on the total amount of a plurality of polyglycols having different molecular weights.
In order to obtain the above Shore hardness, the hard segment content must be at least 40% by weight, and 80% by weight.
Above is too hard and loses flexibility. Therefore, the content of the hard segment component is preferably from 40 to 80% by weight, and more preferably from 50 to 70% by weight.

As the polyglycol, polycaprolactone glycol, polyadipate glycol, polyether glycol, polycarbonate glycol and the like are preferable, and polycaprolactone glycol is particularly preferable.
The plurality of polyglycols need not all be the same, but are preferably the same from the viewpoint of compatibility.

Examples of the diisocyanate include aromatic diisocyanates (for example, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, etc.),
It is preferable to use an aliphatic diisocyanate (eg, hexamethylene diisocyanate) or an alicyclic diisocyanate (eg, isophorone diisocyanate).
A particularly preferred diisocyanate is 4,4'-diphenylmethane diisocyanate.

The chain extender is a low molecular weight diol, for example, 1,4-butanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,6-hexanediol and the like. A particularly preferred chain extender is 1,4-butanediol. Alternatively, ethylene diamine, butylene diamine, hexamethylene diamine, or the like may be used as a chain extender to partially introduce a urea bond.

The indwelling catheter of the present invention has excellent dynamic storage modulus, its rate of decrease due to wetting, initial modulus, kink resistance and / or Shore hardness.

With regard to the dynamic storage modulus, the indwelling catheter according to the preferred embodiment of the present invention has a dynamic storage modulus of 1 GPa or more in a dry state at 25 ° C. and a wet storage temperature of 37 ° C. from a dry state at 25 ° C. The rate of decrease in the dynamic storage modulus when the state is changed is less than 60% after 20 seconds, and 60% or more after 1 minute.

For the measurement of the dynamic storage modulus, a dynamic storage modulus measurement apparatus (DVA-225, manufactured by IT Measurement Control Co., Ltd.) capable of measuring in water is used. The dynamic storage elastic modulus in a dry state at 25 ° C. is measured for 5 minutes at a measurement frequency of 10 Hz without fixing the sample in a jig and water in the apparatus. Next, to determine the rate of decrease in the dynamic storage modulus, 37 ° C.
The storage of water is maintained and the dynamic storage modulus is measured over time. The dynamic storage modulus decreases at the same time as the circulation of warm water at 37 ° C., and saturates to a substantially constant value after 30 minutes. Therefore, the magnitude of the change in the dynamic storage elasticity at the time when 30 minutes have passed since the temperature was changed from the dry state at 25 ° C. to the wet state at 37 ° C. is set as a reference (100%), and the time t in the wet state at 37 ° C.
There the reduction rate E _p of dynamic storage modulus upon lapse of the following formula: E _p = [(E0-Et) / (E0 -E30) ] × 100
% (Where E0 is the dynamic storage elastic modulus in a dry state at 25 ° C., E30 is the dynamic storage elastic modulus after 30 minutes in a wet state at 37 ° C., and Et is the wet storage elasticity at 37 ° C.) This is the dynamic storage modulus when the time t has elapsed.)

The dynamic storage modulus in a dry state at 25 ° C. is 1
If it is less than GPa, the indwelling catheter lacks stiffness,
Poor operability during puncture. In addition, make it wet at 37 ° C.
If the rate of decrease in the dynamic storage modulus at the time of 0 seconds is 60% or more, the indwelling catheter in the wet state is too soft to be flexible, and the operability is also poor. On the other hand, if the decrease rate of the dynamic storage modulus after one minute has passed is less than 60%, the softening in the wet state is too slow, and the blood vessel wall may be damaged. More preferred dynamic storage modulus is 55% or less after 20 seconds, and 65% or more after 1 minute.

In order to satisfy the operability at the time of puncturing, the initial elastic modulus is preferably as high as that of an indwelling needle made of a fluororesin, and is preferably 50 kgf / mm ² or more in a dry state at 25 ° C. In order to suppress damage to blood vessels after placement, the pressure is preferably 25 kgf / mm ² or less within 5 minutes in a wet state at 37 ° C. More preferably, it is 55k in a dry state at 25 ° C.
gf / mm ² or more and within 20 minutes in a wet state at 37 ° C.
kgf / mm ² or less. As described above, the degree of softening from the time of puncturing to the time of indwelling is important, and in order to realize the optimum degree of softening, the initial elastic modulus is 25 kgf / in a change from a dry state at 25 ° C to a wet state at 37 ° C. It is preferably lowered mm ² or more, and more preferably reduced 35 kgf / mm ² or more.

The initial modulus of elasticity was measured using a tensile tester, Strograph T (manufactured by Toyo Seiki Seisaku-sho, Ltd.), in a dry state at 25 ° C. and a wet state after immersion in warm water at 37 ° C. for a predetermined time. In each, the distance between the marked lines is 10 mm
A tensile test was performed at a test speed of 5 mm / min, and the stress-strain curve was calculated from the initial linear portion.

Kink resistance is 10 mm in a wet state at 37 ° C. in order to stably secure a sufficient flow rate during indwelling in a blood vessel.
It is preferably at least 12 mm, more preferably at least 12 mm, even more preferably at least 14 mm. Also, the kink resistance in a dry state at 25 ° C. is preferably 10 mm or more, more preferably 12 mm or more, and still more preferably 14 mm or more.

The kink resistance is measured using a compression tester Autograph AGS-100A (manufactured by Shimadzu Corporation, hereinafter referred to as compression tester A) shown in FIG. Compression testing machine A
Is provided with a gripper 7 provided at the upper part, which can be moved at a constant speed in the vertical direction, and a fixed gripper 7 'provided at the lower part, and is cut into a predetermined length between the grippers 7, 7'. The catheter 6 is arranged so that a compression test in the axial direction is performed, and a change in load applied to the catheter 6 can be recorded on a chart. With this compression tester A, a sample length of 8
Is measured at a test speed of 50 mm / min in a dry state at 25 ° C. and a wet state after immersion in warm water at 37 ° C. for a predetermined time, as follows.

As the catheter 6 is compressed in the axial direction as shown in FIG. 2, the load applied to the catheter changes.
FIG. 3 is a chart showing the load change. Axial compression of the catheter instantaneously increases the load on the catheter, but decreases when it begins to flex.
As compression continues, the lumen of the catheter collapses and begins to block (i.e., kink), causing a greater change in load drop, creating an inflection point on the chart [kink start point]. The load becomes almost constant at the same time as the catheter lumen is almost closed,
An inflection point also appears on the chart at this time [kink point]. On the chart, the time from the start of the compression test [starting point] to the closing of the catheter lumen [kinking point] is determined, and the kink resistance is represented by the moving distance 9 (mm) of the gripper 7 moved during this time.

In order to obtain good operability at the time of puncturing, the shore hardness of each polyurethane resin is preferably 60 D or more. When the Shore hardness is less than 60D, the stiffness of the catheter is not sufficient, and there is a possibility that operability at the time of puncturing may be impaired. Those having a Shore hardness of more than 85D have low extrudability and are difficult to mold into a desired catheter. A practically more preferable range of Shore hardness is 65 to 80.
D.

The indwelling catheter of the present invention has a stripe made of a polyurethane resin mixed with an X-ray opaque substance so that the position can be confirmed by X-rays when the catheter is accidentally cut after the indwelling. May be. To form a stripe, a polyurethane resin mixed with an X-ray opaque substance, for example, barium sulfate, tungsten, bismuth oxide, bismuth carbonate, gold, etc., is mixed with a polyurethane resin not mixed with an X-ray opaque substance. It can be easily manufactured by extrusion. Of course, what can be used as the X-ray opaque substance is not limited to the above. The stripes can be easily formed by common co-extrusion, and the design of the extrusion die allows the stripes to be formed into the desired shape and number.

[0032]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
The polyurethane resin used in the examples was prepared by adding 4,4 ′ as a diisocyanate to a plurality of soft segment components.
-Diphenylmethane diisocyanate (MDI) and another component consisting of 1,4-butanediol as a diol are blended at a molar ratio of [NCO] / [OH] = 1 and synthesized by a one-shot method or a prepolymer method. It was done. The "other components" used in the following examples are the same as those described above.

EXAMPLE 1 22.2% by weight of polycaprolactone glycol having a molecular weight of 550 and 200
16.6% by weight of polycaprolactone glycol,
And the other components described above, a polyurethane resin having a Shore hardness of 78D was synthesized, and the inner diameter was 0.66 mm and the outer diameter was 0.8.
A 9 mm catheter 6 was extruded. The catheter 6 is joined to the hub 3 with caulking pins (not shown) so that the catheter 6 has an effective length of 25 mm, the inner needle 2 joined to the inner needle hub 4 is inserted into the catheter cavity, and the inner needle is further inserted. The indwelling needle 1 shown in FIG. 1 was produced by connecting the filter cap 5 to the rear end of the hub 4.

A tensile test was performed on the catheter 6 used for the indwelling needle 1 using a tensile tester, Strograph T (manufactured by Toyo Seiki Seisaku-sho, Ltd.) according to the method described above.
The initial elastic modulus in a dry state at 25 ° C. and a wet state after immersion in warm water at 37 ° C. for a predetermined time were measured.

The kink resistance of the catheter 6 was measured at 25 ° C. using the compression tester A shown in FIG.
Was measured in a dry state and in a wet state after being immersed in warm water at 37 ° C. for a predetermined time.

The initial elastic modulus and kink resistance of this catheter
The properties were as shown in FIG. 4 and FIG. Dry at 25 ° C
The initial elastic modulus in a dry state (0 minute in FIG. 4) is 56 kgf /
mm ^TwoShows sufficient stiffness for vessel placement
did. In the wet state at 37 ° C, it quickly becomes flexible,
15 kgf / mm after 5 minutes^TwoAnd shows good flexibility
Was. The kink resistance is in a dry state at 25 ° C (0 minutes in Fig. 5).
Immersed in warm water of 14.3 mm, 37 ° C for 10 minutes
After that, it was as good as 18.4 mm.

EXAMPLE 2 Polyurethane resin having a Shore hardness of 77D was prepared by adding 23% by weight of polycaprolactone glycol having a molecular weight of 550, 16% by weight of polycaprolactone glycol having a molecular weight of 2,000 and 16% by weight based on 100% by weight of the whole components. Was synthesized, and a catheter 6 having an inner diameter of 0.65 mm and an outer diameter of 0.88 mm was extruded. Using this catheter 6, an indwelling needle 1 was produced in the same manner as in Example 1, and the initial elastic modulus and kink resistance of the catheter 6 were measured in the same manner as in Example 1.

The initial elastic modulus of this catheter in a dry state at 25 ° C. is as high as 59 kgf / mm ² , indicating that the stiffness is strong at the time of puncturing, and that the operation for indwelling the blood vessel is easy.
It quickly becomes soft when wet at 15 ° C and 15 minutes after 5 minutes.
It showed good flexibility of kgf / mm ² . The kink resistance was as good as 14.1 mm in a dry state at 25 ° C. and 14.7 mm after immersion in warm water at 37 ° C. for 10 minutes.

Further, according to the above-mentioned test method, 25
The dynamic storage elastic modulus of this catheter was measured at 20 ° C. in a dry state at 37 ° C., at 20 ° C. after a wet state at 37 ° C., and at 1 minute after the wet state at 37 ° C.
The reduction rate of the dynamic storage modulus after one minute was determined. Table 1 shows the results. The dynamic storage modulus in a dry state at 25 ° C. is 1.3 G
Pa, the decrease rate of the dynamic storage modulus after 20 seconds as a wet state at 37 ° C. is 55%, the decrease rate after 1 minute is 68%,
It exhibited good dynamic storage modulus lowering behavior.

Example 3 Polycaprolactone glycol having a molecular weight of 1000 was 16% by weight, and the molecular weight was 2000
Of polycaprolactone glycol of 13.5% by weight and the other components described above to synthesize a polyurethane resin having a Shore hardness of 77D, an inner diameter of 0.64 mm and an outer diameter of 0.88
mm catheter 6 was extruded. Using this catheter 6, an indwelling needle 1 was produced in the same manner as in Example 1, and the initial elastic modulus and kink resistance of the catheter 6 were measured in the same manner as in Example 1.

The initial elastic modulus of this catheter in a dry state at 25 ° C. is 58 kgf / mm ^2, and the stiffness is strong at the time of puncturing, and the operation for indwelling the blood vessel is easy. Showed a good flexibility of 18 kgf / mm ² . The kink resistance was as good as 13.2 mm in a dry state at 25 ° C. and 14.8 mm after immersion in warm water at 37 ° C. for 10 minutes.

Example 4 18.5% by weight of polyhexamethylene carbonate glycol having a molecular weight of 1,000, 21% by weight of polyhexamethylene carbonate glycol having a molecular weight of 2000, and 100% by weight of the whole components, and the above-mentioned other components were charged.
A polyurethane resin having a Shore hardness of 76D was synthesized, and a catheter 6 having an inner diameter of 0.65 mm and an outer diameter of 0.89 mm was extruded. Using this catheter 6, an indwelling needle 1 was produced in the same manner as in Example 1, and the initial elastic modulus and kink resistance of the catheter 6 were measured in the same manner as in Example 1.

The initial elastic modulus of this catheter in a dry state at 25 ° C. was as high as 58 kgf / mm ² , indicating that the puncture was strong and the vascular indwelling operation was easy. Also 37
It quickly becomes soft when wet at 20 ° C and 20 minutes after 5 minutes.
It showed good flexibility of kgf / mm ² . The kink resistance was as good as 13.9 mm in a dry state at 25 ° C. and 14.5 mm after immersion in warm water at 37 ° C. for 10 minutes.

EXAMPLE 5 19.2% by weight of polytetramethylene glycol having a molecular weight of 650 and 200
16.8% by weight of polytetramethylene glycol,
And the other components described above, a polyurethane resin having a Shore hardness of 78D was synthesized, and the inner diameter was 0.65 mm and the outer diameter was 0.8.
A 7 mm catheter 6 was extruded. Using this catheter 6, an indwelling needle 1 was produced in the same manner as in Example 1, and the initial elastic modulus of the catheter 6 was measured in the same manner as in Example 1.

The initial elastic modulus of this catheter in a dry state at 25 ° C. is as high as 65 kgf / mm ² , indicating that the puncture is strong and the indwelling operation of the blood vessel is easy. Also 37
It quickly becomes flexible in the wet state at ℃, and after 21 minutes, it becomes 21
It showed good flexibility of kgf / mm ² .

Comparative Example 1 An indwelling needle was prepared from a catheter having an inner diameter of 0.64 mm and an outer diameter of 0.83 mm extruded using an ethylene-tetrafluoroethylene resin, and the initial elastic modulus and kink resistance of the catheter were measured in Example 1. It measured similarly to. The initial elastic modulus and kink resistance of this catheter were as shown in FIGS. The initial elastic modulus in a dry state at 25 ° C. is 63.
At kgf / mm ² , sufficient elasticity was exhibited for the vessel placement operation, but the initial elastic modulus was 5 even at 37 ° C. in a wet state.
It was hardly softened to 9 kgf / mm ² . The kink resistance is 7.0 mm when dried at 25 ° C.
It was as low as 6.8 mm after being immersed in warm water of 10 ° C. for 10 minutes.

Comparative Example 2 An indwelling needle was prepared from a catheter having an inner diameter of 0.68 mm and an outer diameter of 0.89 mm which was extruded from a polyurethane resin containing 37% by weight of a soft segment composed of polycaprolactone glycol having a molecular weight of 550, and Was measured for the initial elastic modulus and kink resistance in the same manner as in Example 1. This catheter had a very high initial elastic modulus in a dry state at 25 ° C. of 100 kgf / mm ^2, and was firm, but had an initial elastic modulus of 30 kgf / mm ² after immersion in warm water at 37 ° C. for 10 minutes. Did not soften enough. The kink resistance is 11.8 mm in a dry state at 25 ° C., and 13.5 mm after being immersed in warm water at 37 ° C. for 10 minutes.
However, the site that kinked once did not recover and remained occluded.

Comparative Example 3 An indwelling needle was prepared from a catheter having an inner diameter of 0.68 mm and an outer diameter of 0.89 mm extruded from a polyurethane resin containing 46% by weight of a soft segment composed of polycaprolactone glycol having a molecular weight of 550. Was measured in the same manner as in Example 1. This catheter has an initial elastic modulus of 15 kgf / mm ^{2 in} a dry state at 25 ° C. and an initial elastic modulus of 1 kgf / mm after immersion in warm water of 37 ° C. for 10 minutes.
² and was very flexible. The kink resistance was 11.1 mm when dried at 25 ° C. and 13.5 mm after immersion in warm water at 37 ° C. for 10 minutes. I was doing it. Also, this catheter was too soft in the wet state at 37 ° C. and was easily crushed.

Comparative Example 4 An indwelling needle was prepared from a catheter having an inner diameter of 0.67 mm and an outer diameter of 0.90 mm, which was extruded using a polyurethane resin containing 32% by weight of a soft segment composed of polycaprolactone glycol having a molecular weight of 2,000. Was measured for the initial elastic modulus and kink resistance in the same manner as in Example 1. The initial elastic modulus and kink resistance of this catheter were as shown in FIGS. The kink resistance is 25
It was 11.5 mm in a dry state at ℃ and 13.2 mm after being immersed in warm water at 37 ° C. for 10 minutes. However, the initial elastic modulus of this catheter in a dry state at 25 ° C. was as high as 63 kgf / mm ² ,
After immersion in warm water of 37 ° C. for 10 minutes, 27 kgf / mm
It was not flexible enough with ² .

Comparative Example 5 An indwelling needle was prepared from a catheter having an inner diameter of 0.66 mm and an outer diameter of 0.88 mm extruded from a polyurethane resin containing 42% by weight of a soft segment composed of polycaprolactone glycol having a molecular weight of 2,000. Was measured for the initial elastic modulus and kink resistance in the same manner as in Example 1. The initial modulus and kink resistance of this catheter are:
As shown in FIGS. 4 and 5. This catheter is 3
Initial elastic modulus after immersion in warm water of 7 ° C for 10 minutes is 8kg
Although it was sufficiently flexible as f / mm ^2, it was as soft as 20 kgf / mm ² even in a dry state at 25 ° C., and the change in elastic modulus was not large. In addition, the pushability was poor, and the puncture procedure was difficult. Kink resistance is 9.2 when dried at 25 ° C.
mm and 10.4 mm after immersion in 37 ° C. warm water for 10 minutes, which was not good.

Comparative Example 6 A commercially available indwelling needle (Fleflocas 22G, manufactured by Nipro Corporation) catheter was used in accordance with the test method described above.
The dynamic storage modulus was measured at the time of drying at 5 ° C. and at the time of 20 seconds and 1 minute after being wet at 37 ° C., and at 20 seconds and 1 minute after being wet at 37 ° C. The rate of decrease in the dynamic storage modulus was determined. Table 1 shows the results.
The dynamic storage elasticity has already been reduced to 75% after 20 seconds in the wet state at 37 ° C., which indicates that the indwelling operation is hindered.

Comparative Example 7 A catheter having an inner diameter of 0.69 mm and an outer diameter of 0.88 mm was extruded from a polyurethane resin having a Shore hardness of 65D containing 42% by weight of a soft segment composed of polytetramethylene glycol having a molecular weight of 2,000. According to the test method described above, 25
C. In the dry state at 37 ° C. and in the wet state at 37 ° C., the dynamic storage modulus was measured at the lapse of 20 seconds and 1 minute,
The decrease rate of the dynamic storage modulus after 20 seconds and 1 minute in the wet state at 37 ° C. was determined. Table 1 shows the results. 37
The decrease rate of the dynamic storage elastic modulus at the time when one minute had elapsed after the wet state at ℃ was as small as 59%.

Table 1 Dynamic storage elastic modulus Drying rate at 25 ° C. Reduction rate (%) Example No. State (GPa) After 20 seconds 1 minute Example 2 1.3 55 68 Comparative Example 6 1.2 75 83 Comparative Example 7 0.81 39 59

[0054]

As described above, in the indwelling catheter of the present invention, the soft segment is composed of a plurality of polyglycols having different molecular weights. The decrease rate of the dynamic storage modulus when the time t has elapsed from the dry state at 25 ° C. to the wet state at 37 ° C. is less than 60% after 20 seconds and 60% or more after 1 minute. . For this reason, the stiffness at the time of puncturing is sufficient, and after the indwelling, it is softened at an appropriate speed. The indwelling catheter of the present invention also
10 in both dry state at 5 ° C and wet state at 37 ° C
It has a kink resistance of at least mm and can safely secure the flow path of the catheter after placement. Also, unlike conventional catheters, there is sufficient stiffness at the time of puncturing without sacrificing kink resistance and becomes flexible at an appropriate speed after placement, so that damage to the blood vessel wall can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of an indwelling needle of the present invention.

FIG. 2 is a schematic diagram showing a compression tester A and a compression test method used for measuring kink resistance.

FIG. 3 is a graph showing the relationship between the load applied to the catheter and the moving distance of the gripper, and shows the kink resistance of the catheter.

FIG. 4 is a graph showing the relationship between the immersion time in warm water at 37 ° C. and the initial elastic modulus.

FIG. 5 is a graph showing the relationship between immersion time in warm water at 37 ° C. and kink resistance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Indwelling needle 2 ... Inner needle 3 ... Hub 4 ... Inner needle hub 5 ... Filter cap 6 ... Catheter 7 ... Holder (movement) 7 '... Holder (Fixed) 8: Sample length 9: Moving distance of gripper

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Kawashima 1500 Inoguchi, Nakai-machi, Ashigara-gun, Kanagawa Prefecture Inside Terumo Corporation

Claims (9)

[Claims] 1. An indwelling catheter formed of one polyurethane resin containing a plurality of polyglycols having different molecular weights. 2. The indwelling catheter according to claim 1, wherein the polyurethane resin is mainly synthesized from a diisocyanate, a diol-based chain extender, and a plurality of polyglycols having different molecular weights. 3. An indwelling catheter made of one polyurethane resin containing a plurality of polyglycols having different molecular weights, wherein the catheter has a dynamic storage modulus in a dry state at 25 ° C. of 1
And at GPa or more, the reduction rate E _p of dynamic storage modulus when a lapse of time t in the wet state 37 ° C. from the dry state of 25 ° C., the following formula: E _p = [(E0-Et) / (E0-E30)] × 100
% (Where E0 is the dynamic storage elastic modulus in a dry state at 25 ° C., E30 is the dynamic storage elastic modulus after 30 minutes in a wet state at 37 ° C., and Et is the wet storage elasticity at 37 ° C.) a dynamic storage modulus when t has elapsed when expressed by.), reduction rate E _p of the dynamic storage modulus at 20 seconds after the 6
Less than 0%, indwelling catheters reduction rate E _p at one minute is equal to or less than 60%. 4. The indwelling catheter according to claim 3, wherein the polyurethane resin comprises a diisocyanate, a diol-based chain extender, and a plurality of polyglycols having different molecular weights. 5. The indwelling catheter according to claim 1, wherein the plurality of polyglycols are a first polyglycol having a molecular weight of 500 to 1500 and a second polyglycol having a molecular weight of 1500 to 3000. Including
An indwelling catheter, wherein the difference between the molecular weight of the first polyglycol and the molecular weight of the second polyglycol is 500 or more. 6. The indwelling catheter according to claim 5, wherein the weight ratio of the first polyglycol to the second polyglycol is from 8: 2 to 2: 8. 7. The indwelling catheter according to claim 1, wherein the polyurethane resin is 4,4′-.
An indwelling catheter, which is a reaction product of diphenylmethane diisocyanate, 1,4-butanediol, and a plurality of polycaprolactone glycols having different molecular weights, and has a Shore hardness of 60 D or more. 8. The indwelling catheter according to claim 1, wherein the kink resistance is 10 mm or more in both a dry state at 25 ° C. and a wet state at 37 ° C. 9. The indwelling catheter according to claim 1, which has an initial elastic modulus of 5 in a dry state at 25 ° C.
0 kgf / mm ² or more, indwelling catheter, characterized in that a 25 kgf / mm ² or less within 5 minutes when wet of 37 ° C..