JP4570708B2 - Indwelling catheter made of polyurethane resin containing multiple polyglycols with different molecular weights - Google Patents

Description

【００５４】
【発明の効果】
以上述べた通り、本発明の留置カテーテルは、ソフトセグメントが分子量の異なる複数のポリグリコールからなるので、２５℃の乾燥状態での動的貯蔵弾性率が１ＧＰａ以上と大きいとともに、２５℃の乾燥状態から３７℃の湿潤状態にして時間ｔが経過したときの動的貯蔵弾性率の低下率が、２０秒経過時に６０％未満であり、かつ１分経過時に６０％以上である。そのため、穿刺時のコシが十分にあるとともに、留置後は適度な速度で柔軟化する。本発明の留置カテーテルはまた２５℃の乾燥状態及び３７℃の湿潤状態のいずれでも１０ｍｍ以上の耐キンク性を有し、留置後のカテーテルの流路を安全に確保することができる。また従来のカテーテルとは異なり、耐キンク性を損なうことなく、穿刺時には十分なコシがあり、留置後は適切な速度で柔軟となるので、血管壁への損傷を著しく軽減できる。
【図面の簡単な説明】
【図１】本発明の留置針の概略図である。
【図２】耐キンク性の測定に使用する圧縮試験機Ａ及び圧縮試験方法を示す概略図である。
【図３】カテーテルにかかる荷重と把持具の移動距離との関係を示すグラフであり、カテーテルの耐キンク性を表す。
【図４】３７℃の温水への浸漬時間と初期弾性率との関係を示すグラフである。
【図５】３７℃の温水への浸漬時間と耐キンク性との関係を示すグラフである。
【符号の説明】
１・・・留置針
２・・・内針
３・・・ハブ
４・・・内針ハブ
５・・・フィルターキャップ
６・・・カテーテル
７・・・把持具（移動）
７’・・把持具（固定）
８・・・サンプル長
９・・・把持具の移動距離[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an indwelling catheter, and more particularly to an indwelling catheter that is used by being placed in a blood vessel for the purpose of infusion of a liquid or medicinal solution into the body, blood transfusion, blood collection, and monitoring of hemodynamics.
[0002]
[Prior art]
Indwelling needles used for infusions and blood transfusions are catheters made of plastic that can be indwelled in blood vessels, and extended from containers containing infusions or medicinal solutions such as infusion bags in the state in which they are placed in blood vessels. Connected tubes are used. Some of the indwelling needles are integrally configured 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 the catheter is punctured into the blood vessel together with the inner needle, and then the inner needle is removed from the indwelling needle.
[0003]
By the way, in order to fulfill the main purpose of the indwelling needle, infusion / medical solution injection, it is important to secure the flow path of the indwelling catheter, and therefore excellent kink resistance is required for the catheter. Furthermore, the operability at the time of puncture and the interaction between the blood vessel walls at the time of puncture and after placement are affected by the mechanical properties of the catheter, so that there is sufficient stiffness at the time of puncture and it is desirable to make it flexible after placement.
[0004]
Conventionally, fluororesins such as polytetrafluoroethylene and ethylene-tetrafluoroethylene copolymers have been mainly used as materials for indwelling catheters. A fluororesin catheter is excellent in operability because it is hard and firm at the time of puncture, and it is 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 risk of hindering the securing of the infusion channel.
[0005]
In view of such circumstances, recently, a polyurethane resin comprising a hard segment and a soft segment and the soft segment comprising a 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 placement of the blood vessel. A method to do is also described. However, this catheter has the problem of poor kink resistance. An indwelling catheter made of polyether polyurethane resin has the disadvantage that even if it becomes flexible after indwelling, sufficient kink resistance is not expressed, and if the catheter is stiffened for operability during puncture, the kink resistance is further impaired. It will be.
[0006]
It is also possible to improve the change in elastic modulus and kink resistance by adjusting the molecular weight of the soft segment. However, when only the polyurethane resin using polyglycol having a molecular weight of 500-1500 is used for the soft segment, the elastic modulus changes greatly from the dry state at 25 ° C. to the wet state at 37 ° C. Even if it is good, there is a drawback that even if it is good, once it is kinked, it does not restore to its original shape. 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 change greatly due to a change from a dry state at 25 ° C. to a wet state at 37 ° C. Thus, when a polyurethane resin containing a soft segment having a substantially single molecular weight is used, it is impossible to satisfy both of the target elastic modulus change amount and kink resistance.
[0007]
Japanese Patent No. 2723190 describes an indwelling needle made of shape memory resin. The catheter of this indwelling needle is hard at the time of blood vessel insertion and becomes flexible after indwelling the blood vessel, but since the speed of the change is too fast, it becomes flexible during the indwelling operation, resulting in an obstacle to the puncture operation. End up.
[0008]
[Problems to be solved by the invention]
Therefore, the object of the present invention is almost the same as that of a fluororesin catheter when inserted into a blood vessel, but it can be softened after placement in the blood vessel to reduce damage to the blood vessel, and has an elastic modulus suitable for the placement operation. It is to provide an indwelling catheter exhibiting a lowering behavior and excellent in kink resistance.
[0009]
[Means for Solving the Problems]
As a result of intensive studies in view of the above object, the present inventors have found that the indwelling catheter has good rigidity (operability) at the time of puncture and is flexible after indwelling to suppress damage to blood vessels. It is important to adjust the rate of decrease in elastic modulus when placed in a wet state at 37 ° C. from the dry state. If the rate of decrease in elastic modulus is too slow, it will take too much time to soften, so We focused on the fact that there is a risk of causing vascular damage, and conversely, if the elastic modulus decreases too rapidly, it may become flexible during placement, making puncture difficult.
[0010]
As a result of examining the softening performance of the polyurethane resin based on this knowledge, it has been found that the degree of softening of the polyurethane resin generally depends greatly on the crystallinity of the polyglycol contained therein. When polyglycol having a low molecular weight is present in the polymer chain, the crystallinity of the polyurethane resin is hardly increased, and crystal melting is promoted by a temperature rise. Therefore, the softening speed of the polyurethane resin with increasing temperature increases.
[0011]
By the way, since polymers having similar molecular structures are generally compatible with each other, they are additive in terms of physical properties when they are blended. Accordingly, polyurethane resins containing polyglycols with different molecular weights are expected to exhibit their average physical properties. However, according to the study by the present inventors, it has been found that the additivity of physical properties does not hold. Therefore, as a result of diligent research, even if polyglycol, which produces a polyurethane resin with inferior properties by itself, is produced in combination with a plurality of polyurethane resins, it has almost the same rigidity as a fluororesin catheter when inserted into a blood vessel. It has been found that an indwelling catheter that can be softened after indwelling to reduce damage to the blood vessels, exhibits a decrease in elastic modulus suitable for indwelling operation, and has excellent kink resistance can be obtained.
[0012]
That is, the indwelling catheter according to the first aspect of the present invention is characterized in that it is formed of one polyurethane resin containing a plurality of polyglycols having different molecular weights.
[0013]
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 elastic modulus of 1 GPa or more in a dry state at 25 ° C. The decrease rate E _p of the dynamic storage elastic modulus when the time t has passed from the dry state to the wet state at 37 ° C. is expressed by the following formula:
E _p = [(E0−Et) / (E0−E30)] × 100%
(However, E0 is the dynamic storage elastic modulus in the dry state of 25 degreeC,
E30 is the dynamic storage modulus after 30 minutes in a wet state at 37 ° C.
Et is a dynamic storage elastic modulus when time t has passed in a wet state of 37 ° C. )
When expressed by a decrease rate of the dynamic storage modulus at 20 seconds after E _p is less than 60%, reduction rate E _p at one minute is equal to or less than 60%.
[0014]
In any embodiment, it is preferable to use a polyurethane resin comprising a diisocyanate, a diol 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, and 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 of the first polyglycol to the second polyglycol is preferably 8: 2 to 2: 8. Furthermore, 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 60D or more.
[0015]
The indwelling catheter according to a 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. Also the initial modulus is at 50 kgf / mm ² or more in the dry state of 25 ° C., a 25 kgf / mm ² or less within 5 minutes when wet of 37 ° C..
[0016]
DETAILED DESCRIPTION OF THE INVENTION
In order to maximize flexibility by changing from a dry state of 25 ° C. to a wet state of 37 ° C., the molecular weight of at least one polyglycol constituting the polyurethane resin is 1500 or less, preferably 500 to 1500. When the molecular weight of the polyglycol is less than 500, it is difficult to exhibit the function as the segmented polyurethane resin, and the properties of the polyurethane resin depend exclusively on the performance of the polyglycol having a large molecular weight. Moreover, by including the second polyglycol having a molecular weight of 1500 to 3000, the polyurethane resin has improved kink resistance. The difference between the molecular weight of the first polyglycol and the molecular weight of the second polyglycol is preferably 500 or more, and more preferably 1000 or more. When the difference in molecular weight between the polyglycols is less than 500, the effect of including a plurality of polyglycols having different molecular weights becomes insufficient. The weight ratio of the first polyglycol to the second polyglycol is preferably 8: 2 to 2: 8. When the weight ratio is outside this range, the effect of using polyglycols having different molecular weights becomes insufficient. “Molecular weight” means number average molecular weight. The molecular weight distribution of the polyglycol used in the present invention is narrow.
[0017]
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 a Shore hardness of 60D or higher, the hard segment content is required to be at least 40% by weight. And loses flexibility. Therefore, the content of the hard segment component is preferably 40 to 80% by weight, and more preferably 50 to 70% by weight.
[0018]
As 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.
[0019]
As the diisocyanate, aromatic diisocyanates (for example, 4,4′-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, etc.), aliphatic diisocyanates (for example, hexamethylene diisocyanate, etc.), and alicyclic diisocyanates (for example, isophorone diisocyanate, etc.) are used. Is preferred. A particularly preferred diisocyanate is 4,4′-diphenylmethane diisocyanate.
[0020]
The chain extender is a low molecular weight diol, and examples thereof include 1,4-butanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and 1,6-hexanediol. A particularly preferred chain extender is 1,4-butanediol. In addition, urea bonds may be partially introduced by using ethylenediamine, butylenediamine, hexamethylenediamine or the like as a chain extender.
[0021]
The indwelling catheter of the present invention has an excellent dynamic storage modulus, its reduction rate due to wetting, initial modulus, kink resistance and / or Shore hardness.
[0022]
Regarding the dynamic storage modulus, the indwelling catheter according to a preferred embodiment of the present invention has a dynamic storage modulus of 1 GPa or more in a dry state at 25 ° C., and changes from a dry state at 25 ° C. to a wet state at 37 ° C. The decrease rate of the dynamic storage elastic modulus at the time of being made is less than 60% when 20 seconds elapse and is 60% or more when 1 minute elapses.
[0023]
For the measurement of the dynamic storage elastic modulus, a dynamic storage elastic modulus measuring device (DVA-225, manufactured by IT Measurement Control Co., Ltd.) capable of underwater measurement is used. The dynamic storage elastic modulus in a dry state at 25 ° C. is measured for 5 minutes under the condition of a measurement frequency of 10 Hz without fixing the sample to a jig and putting water in the apparatus. Next, in order to obtain the decreasing rate of the dynamic storage elastic modulus, water kept at 37 ° C. is circulated, and the dynamic storage elastic modulus is measured over time. The dynamic storage modulus decreases at the same time as the circulation of hot water at 37 ° C., and saturates to a substantially constant value after 30 minutes. Therefore, the change in the dynamic storage elastic modulus after 30 minutes has passed from the dry state at 25 ° C. to the wet state at 37 ° C. is taken as the reference (100%), and the time t has elapsed in the wet state at 37 ° C. The rate of decrease E _p of the dynamic storage elastic modulus when
E _p = [(E0−Et) / (E0−E30)] × 100%
(Where E0 is the dynamic storage modulus in the dry state at 25 ° C., E30 is the dynamic storage modulus after 30 minutes in the wet state at 37 ° C., and Et is the time in the wet state at 37 ° C. It is a dynamic storage elastic modulus when t has elapsed).
[0024]
When the dynamic storage elastic modulus in a dry state at 25 ° C. is less than 1 GPa, the indwelling catheter lacks stiffness and is inferior in operability at the time of puncture. Further, if the rate of decrease in the dynamic storage elastic modulus after 20 seconds in a wet state at 37 ° C. is 60% or more, the indwelling catheter in the wet state is too flexible and is also inferior in operability. On the other hand, if the rate of decrease in the dynamic storage elastic modulus after 1 minute is less than 60%, the softening in the wet state is too slow, and the blood vessel wall may be damaged. A more preferable dynamic storage elastic modulus is 55% or less after 20 seconds, and 65% or more after 1 minute.
[0025]
In order to satisfy the operability at the time of puncture, the initial elastic modulus is preferably as high as a fluororesin indwelling needle and is preferably 50 kgf / mm ² or more in a dry state at 25 ° C. In addition, in order to suppress damage to blood vessels after placement, it is preferably 25 kgf / mm ² or less within 5 minutes in a wet state at 37 ° C. More preferably, it is 55 kgf / mm ² or more in a dry state at 25 ° C. and 20 kgf / mm ² or less in a wet state at 37 ° C. within 5 minutes. As described above, the degree of softening from the time of puncture to the indwelling is important, and in order to realize the optimum degree of softening, the initial elastic modulus is 25 kgf / kg in the change from the dry state at 25 ° C. to the wet state at 37 ° C. It is preferable to decrease by mm ² or more, and more preferably to decrease by 35 kgf / mm ² or more.
[0026]
The initial elastic modulus was measured in a dry state at 25 ° C. and a wet state after being immersed in warm water at 37 ° C. for a predetermined time using a tensile tester Strograph T type (manufactured by Toyo Seiki Seisakusho Co., Ltd.). A tensile test was performed at a line distance of 10 mm and a test speed of 5 mm / min, and was calculated from the initial straight line portion of the obtained stress-strain curve.
[0027]
The kink resistance is preferably 10 mm or more, more preferably 12 mm or more, and still more preferably 14 mm or more in a wet state at 37 ° C. in order to stably secure a sufficient flow rate during placement in the blood vessel. Also, the kink resistance in a dry state at 25 ° C. is preferably 10 mm or more, more preferably 12 mm or more, and further preferably 14 mm or more.
[0028]
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. The compression tester A includes a gripping tool 7 provided at the upper part and movable in a vertical direction at a constant speed, and a fixed gripping tool 7 'provided at the lower part, and a predetermined gap between the gripping tools 7 and 7'. A long-cut catheter 6 is arranged, an axial compression test is performed, and changes in the load applied to the catheter can be recorded on a chart. With this compression tester A, the catheter 6 with a sample length 8 of 25 mm was dried at 25 ° C. and wet at 37 ° C. for a predetermined time at a test speed of 50 mm / min. To measure.
[0029]
When the catheter 6 is compressed in the axial direction as shown in FIG. 2, the load applied to the catheter changes. FIG. 3 shows the load change in a chart. When the catheter is compressed in the axial direction, the load applied to the catheter increases instantaneously, but the load decreases when it begins to bend. As the compression continues further, the lumen of the catheter collapses and begins to occlude (ie, kinks), and the change in load drop increases, creating an inflection point on the chart [kink start point]. At the same time as the lumen of the catheter is almost occluded, the load becomes almost constant, but at this time, an inflection point is generated on the chart [kink point]. On the chart, determination is made from the time point [start point] when the compression test is started to the time point [kink point] where the catheter lumen is blocked, and kink resistance is expressed by the moving distance 9 (mm) of the gripping tool 7 moved during this time.
[0030]
In order to obtain good operability at the time of puncture, the Shore hardness of each polyurethane resin is preferably 60D or more. If the Shore hardness is less than 60D, the stiffness of the catheter is not sufficient, and the operability at the time of puncture may be hindered. It should be noted that those having a Shore hardness exceeding 85D have low extrusion moldability and are difficult to be molded into a desired catheter. The range of Shore hardness that is more preferable in practical use is 65 to 80D.
[0031]
The indwelling catheter of the present invention may have a stripe formed by mixing an X-ray impermeable substance with polyurethane resin so that the position can be confirmed by X-ray when a catheter cutting accident occurs after indwelling. . In order to form the stripe, a resin in which a polyurethane resin is mixed with an X-ray opaque material such as barium sulfate, tungsten, bismuth oxide, bismuth carbonate, and gold is mixed with a polyurethane resin not mixed with an X-ray opaque material. It can be easily manufactured by extrusion. Of course, what can be used as a radiopaque substance is not limited to the above. The stripes can be easily formed by general coextrusion, and the stripes can be formed in a desired shape and number depending on the design of the extrusion die.
[0032]
【Example】
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the polyurethane resin used in the examples, a plurality of soft segment components were mixed with other components consisting of 4,4′-diphenylmethane diisocyanate (MDI) as diisocyanate and 1,4-butanediol as diol, [NCO] / The [OH] molar ratio is 1 and is synthesized by a one-shot method or a prepolymer method. The “other components” used in the following examples are the same as those described above.
[0033]
Example 1
Polyurethane resin with a Shore hardness of 78D was synthesized by adding 100% by weight of the total ingredients, 22.2% by weight of polycaprolactone glycol having a molecular weight of 550, 16.6% by weight of polycaprolactone glycol having a molecular weight of 2000, and the above other ingredients. The catheter 6 having an inner diameter of 0.66 mm and an outer diameter of 0.89 mm was extruded. The catheter 6 is joined to the hub 3 with a caulking pin (not shown) so as to have an effective length of 25 mm, the inner needle 2 joined to the inner needle hub 4 is inserted into the catheter lumen, and the inner needle A filter cap 5 was connected to the rear end of the hub 4 to produce the indwelling needle 1 shown in FIG.
[0034]
The catheter 6 used for the indwelling needle 1 is subjected to a tensile test using a tensile tester Strograph T type (manufactured by Toyo Seiki Seisakusyo Co., Ltd.) according to the above-described method. The initial elastic modulus in a wet state after being immersed in warm water for a predetermined time was measured.
[0035]
The kink resistance of the catheter 6 was measured in a dry state at 25 ° C. and a wet state after being immersed in warm water at 37 ° C. for a predetermined time according to the method described above using the compression tester A shown in FIG.
[0036]
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. (0 minutes in FIG. 4) was 56 kgf / mm ² , indicating a sufficient firmness for the vessel placement operation. Moreover, it became flexible quickly in a wet state of 37 ° C., and showed a good flexibility of 15 kgf / mm ² after 5 minutes. The kink resistance was as good as 14.3 mm in a dry state at 25 ° C. (0 minutes in FIG. 5) and 18.4 mm after being immersed in warm water at 37 ° C. for 10 minutes.
[0037]
Example 2
100% by weight of the entire component, 23% by weight of polycaprolactone glycol having a molecular weight of 550, 16% by weight of polycaprolactone glycol having a molecular weight of 2000, and the other components described above were synthesized to synthesize a polyurethane resin having a Shore hardness of 77D, and an inner diameter of 0%. A catheter 6 having a diameter of .65 mm and an outer diameter of 0.88 mm was extruded. Using this catheter 6, the 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.
[0038]
The initial elastic modulus of the catheter in a dry state at 25 ° C. is as high as 59 kgf / mm ^2, and it can be seen that the puncture is strong and easy to place the blood vessel, and in the wet state at 37 ° C., the catheter becomes quickly flexible. After 5 minutes, 15 kgf / mm ² and a good flexibility were exhibited. The kink resistance was 14.1 mm in a dry state at 25 ° C. and 14.7 mm after being immersed in warm water at 37 ° C. for 10 minutes.
[0039]
Further, according to the test method described above, the dynamic storage elastic modulus of this catheter was measured when 20 seconds passed and after 1 minute passed in a dry state of 25 ° C. and a wet state of 37 ° C., respectively. The decrease rate of the dynamic storage elastic modulus after 20 seconds and 1 minute was determined. The results are shown in Table 1. The dynamic storage elastic modulus in a dry state at 25 ° C. is 1.3 GPa, the decrease rate of the dynamic storage elastic modulus after 20 seconds in a wet state of 37 ° C. is 55%, and the decrease rate after 1 minute is 68%. In addition, it showed a good dynamic storage modulus lowering behavior.
[0040]
Example 3
100% by weight of the total components, 16% by weight of polycaprolactone glycol having a molecular weight of 1000, 13.5% by weight of polycaprolactone glycol having a molecular weight of 2000, and the other components described above were synthesized, and a polyurethane resin having a Shore hardness of 77D was synthesized. A catheter 6 having an inner diameter of 0.64 mm and an outer diameter of 0.88 mm was extruded. Using this catheter 6, the 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.
[0041]
The initial elastic modulus of this catheter in a dry state at 25 ° C. is 58 kgf / mm ^2, which is strong at the time of puncture and easy to place a blood vessel, and quickly becomes flexible in a wet state at 37 ° C. After 18 minutes, 18 kgf / mm ² and good flexibility were shown. The kink resistance was as good as 13.2 mm in a dry state at 25 ° C. and 14.8 mm after being immersed in warm water at 37 ° C. for 10 minutes.
[0042]
Example 4
Polyurethane resin having a Shore hardness of 76D, containing 100% by weight of the total components, 18.5% by weight of polyhexamethylene carbonate glycol having a molecular weight of 1000, 21% by weight of polyhexamethylene carbonate glycol having a molecular weight of 2000, and the above other components. 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, the 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.
[0043]
The initial elastic modulus of this catheter in a dry state at 25 ° C. is as high as 58 kgf / mm ^2, and it can be seen that the catheter is strong and easy to place the blood vessel during puncture. Moreover, it became flexible quickly in a wet state at 37 ° C., and showed a good flexibility of 20 kgf / mm ² after 5 minutes. The kink resistance was 13.9 mm in a dry state at 25 ° C. and 14.5 mm after being immersed in warm water at 37 ° C. for 10 minutes.
[0044]
Example 5
Polyurethane resin having a Shore hardness of 78D with 100% by weight of the total components, 19.2% by weight of polytetramethylene glycol having a molecular weight of 650, 16.8% by weight of polytetramethylene glycol having a molecular weight of 2000, and the above other components. And a catheter 6 having an inner diameter of 0.65 mm and an outer diameter of 0.87 mm was extruded. Using this catheter 6, the 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.
[0045]
The initial elastic modulus of this catheter in a dry state at 25 ° C. is as high as 65 kgf / mm ^2, and it can be seen that the puncture is strong and easy to place the blood vessel. Moreover, it became flexible quickly in a wet state of 37 ° C., and showed a good flexibility of 21 kgf / mm ² after 5 minutes.
[0046]
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 ethylene-tetrafluoroethylene resin, and the initial elastic modulus and kink resistance of the catheter were measured in the same manner as in Example 1. 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. was 63 kgf / mm ² , which showed sufficient stiffness for indwelling blood vessels, but the initial elastic modulus was almost 59 kgf / mm ² even in a wet state at 37 ° C. Not flexible. The kink resistance was 7.0 mm when dried at 25 ° C., and was as low as 6.8 mm after being immersed in warm water at 37 ° C. for 10 minutes.
[0047]
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 extruded using a polyurethane resin containing 37% by weight of a soft segment made of polycaprolactone glycol having a molecular weight of 550, and the initial elastic modulus and resistance of the catheter were measured. The kink property was measured in the same manner as in Example 1. This catheter had a very high initial elastic modulus of 100 kgf / mm ^{2 in} a dry state at 25 ° C. and was stiff, but the initial elastic modulus after being immersed in warm water at 37 ° C. for 10 minutes was 30 kgf / mm ² . It was not flexible enough. The kink resistance was 11.8 mm in a dry state at 25 ° C. and was 13.5 mm after being immersed in warm water at 37 ° C. for 10 minutes. was.
[0048]
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 using a polyurethane resin containing 46% by weight of a soft segment made of polycaprolactone glycol having a molecular weight of 550, and the initial elastic modulus and resistance of the catheter were measured. The kink property was measured in the same manner as in Example 1. This catheter had a flexible initial elastic modulus of 15 kgf / mm ^{2 in} a dry state at 25 ° C., and an initial elastic modulus of 1 kgf / mm ² after being immersed in warm water at 37 ° C. for 10 minutes. . The kink resistance was 11.1 mm in a dry state at 25 ° C. and 13.5 mm after being immersed in warm water at 37 ° C. for 10 minutes. I did. In addition, this catheter was too flexible when it was wet at 37 ° C. and was easily crushed.
[0049]
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 extruded using a polyurethane resin containing 32% by weight of a soft segment made of polycaprolactone glycol having a molecular weight of 2000, and the initial elastic modulus and resistance of the catheter were measured. The kink property was measured 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 was 11.5 mm in a dry state at 25 ° C. and was good at 13.2 mm after being immersed in warm water at 37 ° C. for 10 minutes. However, the initial modulus in the dry state of 25 ° C. The catheter was as high as 63kgf / mm ^2, after being immersed for 10 minutes in a 37 ° C. hot water did not become sufficiently flexible and 27 kgf / mm ^2.
[0050]
Comparative Example 5
An indwelling needle was produced from a catheter having an inner diameter of 0.66 mm and an outer diameter of 0.88 mm extruded using a polyurethane resin containing 42% by weight of a soft segment made of polycaprolactone glycol having a molecular weight of 2000, and the initial elastic modulus, The kink property was measured in the same manner as in Example 1. The initial elastic modulus and kink resistance of this catheter were as shown in FIGS. Although this catheter was sufficiently flexible with an initial elastic modulus of 8 kgf / mm ² after being immersed in warm water at 37 ° C. for 10 minutes, it was flexible with 20 kgf / mm ² even in a dry state at 25 ° C. Was not big. In addition, the pushability was poor and the puncture technique was difficult. The kink resistance was 9.2 mm in a dry state at 25 ° C., and after being immersed in warm water at 37 ° C. for 10 minutes, it was not as good as 10.4 mm.
[0051]
Comparative Example 6
Regarding the catheter of a commercially available indwelling needle (Fleflocas 22G, manufactured by Nipro Co., Ltd.) according to the above-described test method, it is dynamic when dried at 25 ° C. and wet at 37 ° C. when 20 seconds elapse and when 1 minute elapses, respectively. The storage elastic modulus was measured, and the decrease rate of the dynamic storage elastic modulus after 20 seconds and 1 minute in a wet state at 37 ° C. was determined. The results are shown in Table 1. After 20 seconds in a wet state at 37 ° C., the dynamic storage elastic modulus has already dropped to 75%, which indicates that the indwelling operation is hindered.
[0052]
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 made of polytetramethylene glycol having a molecular weight of 2000. According to the test method described above, the dynamic storage elastic modulus of this catheter was measured after 20 seconds and 1 minute in a dry state at 25 ° C. and in a wet state at 37 ° C., and in a wet state at 37 ° C. The decrease rate of the dynamic storage elastic modulus after 20 seconds and 1 minute was determined. The results are shown in Table 1. The decrease rate of the dynamic storage elastic modulus after 1 minute in a wet state of 37 ° C. was as small as 59%.
[0053]

[0054]
【The invention's effect】
As described above, since the indwelling catheter of the present invention is composed of a plurality of polyglycols having different molecular weights, the dynamic storage elastic modulus in a dry state at 25 ° C. is as large as 1 GPa or more and a dry state at 25 ° C. The decrease rate of the dynamic storage elastic modulus when the time t elapses in a wet state of 37 ° C. is less than 60% when 20 seconds elapse and is 60% or more when 1 minute elapses. For this reason, there is sufficient stiffness at the time of puncturing, and it is softened at an appropriate speed after placement. The indwelling catheter of the present invention also has a kink resistance of 10 mm or more in both a dry state at 25 ° C. and a wet state at 37 ° C., and the flow path of the indwelling catheter can be secured safely. Also, unlike conventional catheters, there is sufficient stiffness at the time of puncture without impairing kink resistance, and flexibility becomes possible at an appropriate speed after placement, so that damage to the blood vessel wall can be remarkably 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 view 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 grasping tool, and represents 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 hot 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 ... Holding tool (movement)
7 '・ ・ Grip (fixed)
8 ... Sample length 9 ... Grip travel distance

Claims (8)

An indwelling catheter formed of one polyurethane resin containing a plurality of polyglycols having different molecular weights , wherein the plurality of polyglycols includes a first polyglycol having a molecular weight of 500 to 1500 and a first polyglycol having a molecular weight of 1500 to 3000. An indwelling catheter comprising two polyglycols, wherein a difference between the molecular weight of the first polyglycol and the molecular weight of the second polyglycol is 500 or more .  The indwelling catheter according to claim 1, wherein the polyurethane resin is mainly synthesized from diisocyanate, a diol chain extender and a plurality of polyglycols having different molecular weights. An indwelling catheter made of one polyurethane resin containing a plurality of polyglycols having different molecular weights, wherein the plurality of polyglycols are a first polyglycol having a molecular weight of 500-1500 and a second polyglycol having a molecular weight of 1500-3000. The difference between the molecular weight of the first polyglycol and the molecular weight of the second polyglycol is 500 or more, and the dynamic storage elastic modulus in a dry state at 25 ° C. is 1 GPa or more, 25 The decrease rate Ep of the dynamic storage elastic modulus when the time t elapses from the dry state at 37 ° C. to the wet state at 37 ° C. is expressed by the following formula: Ep = [(E0−Et) / (E0−E30)] × 100 % (Where E0 is the dynamic storage modulus in the dry state at 25 ° C., E30 is the dynamic storage modulus after 30 minutes in the wet state at 37 ° C., and Et is the wet storage at 37 ° C.) The dynamic storage elastic modulus when the time t has elapsed in the state.) When the dynamic storage elastic modulus decrease rate Ep after 20 seconds is less than 60%, the decrease after 1 minute has elapsed. An indwelling catheter, characterized in that the rate Ep is 60% or more.  4. The indwelling catheter according to claim 3, wherein the polyurethane resin comprises a diisocyanate, a diol chain extender, and a plurality of polyglycols having different molecular weights. The indwelling catheter according to any one of claims 1 to 4 , wherein a weight ratio of the first polyglycol to the second polyglycol is 8: 2 to 2: 8. The indwelling catheter according to any one of claims 1 to 5 , wherein 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, An indwelling catheter having a Shore hardness of 60D or more. The indwelling catheter according to any one of claims 1 to 6 , wherein kink resistance is 10 mm or more in both a dry state at 25 ° C and a wet state at 37 ° C. The indwelling catheter according to any one of claims 1 to 7 , wherein the initial elastic modulus is 50 kgf / mm2 or more in a dry state at 25 ° C, and when it is in a wet state at 37 ° C, it is 25 kgf / mm2 or less within 5 minutes. An indwelling catheter.

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