JP2001252348A - Tube for medical treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube for medical treatment which is excellent not only in rigidity, pliability, transparency and heat resistance but also in bending elasticity and tensile strength, and is free of the tacky adhesivenss between the tubes. SOLUTION: The tube for medical treatment consists of a resin composition containing low density ethylene of 0.860 to 0.900 g/cm3 in density polymerized by a metallocene catalyst/α-olefinic copolymer and styrene/ethylene-butyrene/ olefin block copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-adhesive medical tube used for an infusion set tube, an extension tube, a blood circuit tube, a blood transfusion set tube, a connecting tube, a winged needle tube and the like.

[0002]

2. Description of the Related Art A medical tube used for an infusion set, a blood circuit, and the like needs to have excellent flexibility, rigidity, transparency, and heat resistance. It is used. However, a soft vinyl chloride resin contains a large amount of dioctyl phthalate or phthalic acid (2-ethylhexyl) as a plasticizer, and the infusion of the plasticizer into a transfusion solution or blood becomes a problem in safety. I have. In addition, since a soft vinyl chloride resin adsorbs fat-soluble drug components such as nitroglycerin, isosorbide dinitrate, and diazepam, it is extremely difficult to accurately administer a required amount when administering a drug containing the components to a patient. It is.

[0003] As a medical base material in consideration of the above-mentioned drawbacks, polyethylene-based resins have attracted attention. For example, a tube made of ultra-low density polyethylene having a specific gravity of 0.89 or less (Japanese Patent Publication No. 1-48775) is known. This resin is excellent in transparency, but has a wide molecular weight distribution and a large amount of low molecular weight components. Tubes formed from this resin are sticky and the inner surfaces of the tubes tend to stick together, and once bent, it takes time to recover to its original shape, during which medical practice may be interrupted. In order to improve this, the use of low-density polyethylene and a thermoplastic α-olefin resin using a metallocene catalyst has also been proposed, but a tube molded from the resin has a stickiness that does not use a metallocene catalyst. Although it is slightly less than that, there is a drawback that the tensile strength is low and the tube is easily cut.

Further, blended resins of linear low-density polyethylene having a density of 0.92 to 0.94 g / cm ³ and a thermoplastic polystyrene-based elastomer, and resins obtained by blending a thermoplastic polyolefin-based elastomer with these resins (particularly, Japanese Patent Publication No. 2-31989, Japanese Patent Publication No. 2-31990
Is also known. As the thermoplastic polystyrene elastomer, styrene / butadiene / styrene elastomer, styrene / ethylene-butylene / styrene elastomer, styrene / ethylene-butadiene / styrene elastomer, and styrene / isoprene / styrene elastomer are disclosed. However, tubes made of these blended resins have a lower flexural modulus and less stickiness depending on the mixing ratio than tubes made of ethylene resin alone, but they have low tensile strength, so they are molded into tubes. The tube is easily damaged when used.

[0005]

In view of the above circumstances, it is an object of the present invention to provide not only rigidity, flexibility, transparency and heat resistance but also excellent bending elasticity and tensile strength, and furthermore, there is no stickiness between tubes. It is to provide a medical tube.

[0006]

Means for Solving the Problems The present inventors have made various studies to solve the above-mentioned problems, and as a result, have found that using a metallocene catalyst-based ethylene copolymer and further blending a specific thermoplastic polystyrene elastomer. As a result, the inventors have found that the above-mentioned disadvantages can be solved, and arrived at the present invention.

That is, the present invention has a density of 0.860-0.900 g /
1 is a medical tube made of a resin composition containing a low-density ethylene / α-olefin copolymer and a styrene / ethylene-butylene / olefin block copolymer of cm ³ .

The low-density ethylene / α-olefin copolymer of the present invention is a copolymer polymerized with a metallocene catalyst, and has a density of 0.860 to 0.900 g / cm.
³ , preferably 0.870 to 0.900 g / cm ³ . 0.860g density
and smaller / cm ^3, a medical tube with the copolymer tensile strength is lowered, also larger than 0.900 g / cm ^3, a medical tube with the copolymer tends to bend too small bending elastic modulus Become something. The molecular weight distribution (Mw (weight average molecular weight) / Mn (number average molecular weight)) of the copolymer is 1.8 to 2.5, which is narrower than the molecular weight distribution of an ethylene copolymer not using a metallocene catalyst, which is 3.0 to 4.5. ing. Thus, the medical tube using the copolymer has low adhesiveness, and there is no possibility that the inner surfaces of the tube will adhere to each other. Further, the molecular weight of the copolymer is 20,000 to 250,000, preferably 30,000 to 15
It is 0,000. If the molecular weight is less than 20,000, the tube using the copolymer will have poor heat resistance, and if it is more than 250,000, the tube using the copolymer will have low transparency, which is not preferable. As the α-olefin contained in the low-density ethylene / α-olefin-based copolymer, one having 4 to 8 carbon atoms is preferable, and specifically, butene-1, pentene-1, 4-methyl-1-pentene, Hexene-1, octene-1 and the like. Specific examples of the copolymer include ethylene / butene-1 copolymer, ethylene / pentene-1 copolymer, and ethylene / butene-1 copolymer.
Examples thereof include 4-methyl-1-pentene copolymer, ethylene / hexene-1 copolymer, ethylene / octene-1 copolymer, and more preferably, ethylene / octene-1 copolymer. Α in the above copolymer
The olefin content is from 10 to 50% by weight, preferably from 15 to
45% by weight. If the content is less than 10% by weight, the medical tube using the copolymer will have too large a flexural modulus, and if it is more than 50% by weight, the medical tube using the copolymer will have high tackiness.

The styrene / ethylene-butylene / olefin block copolymer in the present invention is a copolymer comprising a polystyrene block, an ethylene-butylene copolymer block and a polyolefin block. The monomers constituting the polystyrene block are styrene and derivatives thereof, for example, p-methylstyrene,
It contains t-butylstyrene, vinylpyridine, α-methylstyrene and the like. The ethylene-butylene copolymer block is at least 80% of the polybutadiene block,
Preferably, it is obtained by hydrogenating at least 90%. If the hydrogenation rate is less than 80%, the copolymer is cross-linked by γ-rays, light and heat during sterilization, so that a medical tube using the copolymer may have too high a hardness. In the polyolefin block, it is preferable that the polyolefin is crystallized. This makes it possible to form a tube having high flexibility while having the same degree of flexibility as a conventional tube made of a thermoplastic polystyrene-based elastomer. As the olefin, those having 2 to 8 carbon atoms are preferable, and specific examples thereof include ethylene, propylene, and butene-1. Considering the affinity with a low-density ethylene / α-olefin copolymer, ethylene is preferable. Is more preferred. The copolymer preferably has a styrene content of 5 to 50% by weight. A copolymer having a styrene content of 10 to 40% by weight is more preferable for obtaining a medical tube having a small flexural modulus and excellent flexibility. The hardness of the above copolymer is 35-85 (Shore A, A
STM D2240), more preferably 60-80. Hardness is 35
Otherwise, medical tubing using the copolymer will have too low a flexural modulus, and once the tube is bent, it will take time to recover to its original shape. In addition, hardness is 85
If it is larger, the flexural modulus is too large, and the flexibility of the tube becomes insufficient.

The content of the low-density ethylene / α-olefin copolymer in the resin composition of the present invention is 10 to 90% by weight, preferably 20 to 80% by weight, more preferably 30 to 70% by weight. When the content is less than 10% by weight, the inner surface of the tube of the medical tube made of the resin composition is likely to stick. On the other hand, if the content is more than 90% by weight, the adhesiveness of the tube is increased again, and the tensile strength is too low and the tube is easily cut.

[0011] The resin composition of the present invention may contain the styrene / ethylene-butylene / ethylene resin in an amount not to impair the bending elasticity and tensile strength of a medical tube made of the resin composition.
A styrene-based elastomer other than the olefin block copolymer may be appropriately added. As the styrene elastomer, styrene / ethylene-butylene / styrene block copolymer, styrene / ethylene-propylene / styrene block copolymer, styrene / butylene /
Styrene block copolymer, styrene / isoprene /
Styrene block copolymers and the like can be mentioned.

Further, the resin composition of the present invention may further contain a lubricant in order to prevent the inner surfaces of the medical tube made of the resin composition from sticking to each other or to reduce the frictional resistance of the outer surface of the tube. May be. Examples of the lubricant include silicone, triglyceride, metal stearate, fatty acid amide, higher fatty acid wax, fatty acid wax and the like. Further, the resin composition of the present invention may contain additives such as an anti-blocking agent and an antioxidant in a range that does not impair the properties of the resin composition.

The medical tube made of the resin composition of the present invention is obtained by melt-kneading pellets of each polymer contained in the resin composition by a twin-screw extruder or the like, and then mixing the pellets by a single-screw extruder or the like. And obtained by extrusion. Alternatively, the pellets of the respective polymers may be directly dry-blended by a single-screw extruder or the like and then extruded into a tube.

The medical tube of the present invention desirably has a flexural modulus of 100 kgf / cm ² or less and a tensile strength of 100 kgf / cm ² or more. If the flexural modulus is greater than 100 kgf / cm ² , the tube is too hard and kinks easily. When the tensile strength is lower than 100 kgf / cm ² , the tube is easily cut.

In the present invention, a tube refers to a tube having a circular cut surface, and in order to be used as a medical tube,
It is preferable that the inner diameter is 1 mm or more and the outer diameter is 1.5 mm or more. The length of the tube is not particularly limited, but is preferably 30 mm or more for use as a medical tube. Further, the medical tube of the present invention may be a single-layer tube made of the resin composition of the present invention or a multilayer tube obtained by laminating the resin composition and another resin. As other resins, ethylene / vinyl acetate copolymer, styrene / ethylene-butylene / styrene copolymer and the like are used.

The medical tube thus obtained is used as an infusion set tube, an extension tube, a blood circuit tube, a transfusion set tube, a connecting tube, a winged needle tube, and the like. The medical tube of the present invention is not only excellent in the bending elasticity and the tensile strength, but also has a high transparency and has no stickiness between the tubes. Therefore, the medical tube is more preferably used as a tube for an infusion set.

[0017]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In the examples, each measurement and observation were performed as follows.

(Measurement of Flexural Modulus and Tensile Strength and Observation of Transparency and Adhesiveness) The flexural modulus was determined by measuring the bending stress according to JIS K7171 using the above tube as a sample. The flexural modulus was calculated according to the formula for calculating the flexural modulus of the cylinder. However, the bending stress was measured by three-point bending, the crosshead speed was 1 mm / min, and the distance between fulcrums was 8 mm. The tensile strength is
Using the tube as it is as a sample, JIS K7113
The breaking strength was measured according to the “Plastic tensile test method”. However, the crosshead speed is 200mm / min,
The distance between the grippers was 20 mm. The transparency of the tube was visually observed, and if bubbles in physiological saline flowing in the tube were confirmed, the tube was judged to have transparency. The adhesiveness of the tube was judged from the adhesiveness of the outer and inner surfaces of the tube. Incidentally, the adhesiveness of the outer surface of the tube was inserted into a stainless steel pipe having an inner diameter of 6 mm in a state where the two tubes were brought into close contact, and the tube was taken out after 30 minutes.
If the two tubes were separated, there was no tackiness. If the tubes were separated but were touched by hand and had a sticky feeling, or if they were still in close contact, they were tackified. In addition, the adhesiveness of the inner surface of the tube is such that when the tube is left in a folded state for 1 minute and then the bending force is removed, the folded portion of the tube returns to its original state within 5 seconds. , And the case where it did not return was regarded as sticky.

Examples 1 to 12 and Comparative Examples 1 to 3 Metallocene-catalyzed ethylene / octene copolymers (A) and styrene / ethylene-butylene / ethylene block copolymers (B) (DYNAR) having various densities shown in Table 1.
ON (registered trademark) 4600P, manufactured by JSR Corporation, styrene content: 20%, specific gravity: 0.91, MFR: 5.6 g / 10 minutes, Shore
A hardness: 78) was mixed at various mixing ratios shown in Table 1, and pellets of the obtained resin composition were mixed with a twin-screw extruder (PCM3).
0, manufactured by Ikegai Iron Works Co., Ltd.) and extruded into a tube having an outer diameter of 3.6 mm and an inner diameter of 2.3 mm by a single screw extruder (UT-25-1 manufactured by Plastics Engineering Laboratory Co., Ltd.). The tubes of Examples 1 to 12 all passed the Medical Materials Association's voluntary standard “Medical Polyethylene”. Table 1 shows the results of measuring or observing the flexural modulus, tensile strength, and transparency and tackiness of the tube.

[0020]

[Table 1] Note) * 1: Engage 8200 * 2: Engage
8411 * 3: Engage 8585 * 4: Affinity
PF 1140 * 5: Nipolon-Z 7P04A * 6: Kernel (registered trademark) 55FI * 1, * 2, * 3, * 4: Dow Chemical Co., Ltd. * 5: Tosoh Corporation * 6: Mitsubishi Chemical Corporation Made

As is clear from Table 1, the medical tube of the present invention is excellent in all of the flexural modulus, tensile strength, transparency and adhesiveness. On the other hand, as shown in the comparative examples, the tubes (Comparative Examples 1 and 2) using either the copolymer (A) or the copolymer (B) have adhesiveness. Further, when the density of the copolymer (A) exceeds the range of the present invention (Comparative Example 3), the bending elastic modulus of the tube becomes large and the tube becomes hard, so that the tube may not be used as a medical tube.

Comparative Examples 4 and 5 Metallocene-catalyzed ethylene / octene copolymer (A) having a density of 0.880 g / cm ³
(Engage 8411, manufactured by Dow Chemical Company) and styrene / ethylene-butylene / styrene block copolymer (B ') (Clayton G 1657, manufactured by Shell Chemical Company, Inc., styrene content: 13%, specific gravity: 0.92, melt index: 8 g) / 10 minutes, shear A hardness: 65) were mixed at various mixing ratios shown in Table 2, and using the obtained resin composition pellets, a tube was prepared in the same manner as in Example 1,
The flexural modulus, tensile strength, transparency and tackiness of the tube were measured or observed. Table 2 shows the results.

[0023]

[Table 2]

As is clear from Table 2, the tube using styrene / ethylene-butylene / styrene block copolymer (B ') instead of styrene / ethylene-butylene / ethylene block copolymer (B) has tackiness. Also, the tensile strength is lower than that of the tube using the copolymer (B).

(Comparative Examples 6, 7 and 8) Density 0.890 g / cm ³
Ziegler-Natta catalyzed low density polyethylene (A ') (polyethylene ZN EUL130, manufactured by Sumitomo Chemical Co., Ltd.) and styrene / ethylene-butylene / ethylene block copolymer (B) (DYNARON (registered trademark))
4600P (manufactured by JSR Corporation) at various mixing ratios shown in Table 3, and using the pellets of the obtained resin composition, a tube was prepared in the same manner as in Example 1. Sex was observed. Table 3 shows the results.

[0026]

[Table 3]

As apparent from Table 3, the tube using the Ziegler-Natta catalyst low-density polyethylene (A ') instead of the metallocene catalyst-based ethylene / octene copolymer (A) has tackiness. Further, the bending elastic modulus and the tensile strength of the tube were not measured because the tube was already sticky and judged to be unsuitable as a medical tube.

[0028]

The medical tube of the present invention is made of styrene /
Since the ethylene-butylene / olefin block copolymer is used, it has excellent bending elasticity and tensile strength, and does not easily cause kink of the tube. In addition, since the molecular weight distribution is narrow and the ethylene-based copolymer with low low molecular weight components is used, it is difficult for the tubes to stick to each other, and even if the tubes are pressed with roller clamps or bent, The recovery is fast, and does not hinder medical practice. Furthermore, when the medical tube of the present invention is stored in the outer package, the tube does not easily adhere to the outer body, so that the tube can be easily taken in and out. Further, after the tube is stored in the outer package, there is no possibility that the outer surfaces of the tube are adhered to each other when the tube is taken out.

Claims (6)

[Claims] 1. A low-density ethylene / α-olefin copolymer having a density of 0.860 to 0.900 g / cm ³ polymerized with a metallocene catalyst and styrene / ethylene-butylene /
A medical tube comprising a resin composition containing an olefin block copolymer. 2. The medical tube according to claim 1, wherein the low-density ethylene / α-olefin-based copolymer is an ethylene / octene-1 copolymer having a density of 0.870 to 0.900 g / cm ³ . 3. The styrene / ethylene-butylene / olefin block copolymer has a styrene content of 5 to 5.
0% by weight and a hardness of 35 to 85 (Shore A, ASTM D224
The medical tube according to claim 1 or 2, which is a block copolymer having 0). 4. The styrene / ethylene-butylene / olefin block copolymer comprises styrene / ethylene-
The medical tube according to any one of claims 1 to 3, which is a butylene / ethylene block copolymer. 5. The content of the low-density ethylene / α-olefin copolymer in the resin composition is 10 to 90% by weight.
The medical tube according to any one of claims 1 to 4, wherein 6. An infusion set using the medical tube according to claim 1.