JPH0940793A - Medical supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a medical supply excellent in transparency, heat resistance, and softness and used for discharging or storing body fluids, drugs, etc. SOLUTION: A linear copolymer of ethylene and a 3-12C α-olefin which has a density of 0.850-0.920g/cm<3> and an Mw /Mn ratio as determined through GPC of 3 or lower and in which the ratio of the average number of branches in a 30wt.% low-mol. fraction obtained by GPC to that in a 30wt.% high-mol. fraction obtained by GPC is 0.8 to 1.2 is formed into a molding, which is crosslinked by irradiation with a radiation and/or electron beams to a degree of crosslinking of 20% or higher.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the discharge or preservation of body fluids, chemicals, etc., which are obtained by irradiating a molded article using a specific ethylene-based copolymer with radiation and / or electron beams to crosslink it. Regarding medical equipment.

[0002]

2. Description of the Related Art Conventionally, polyvinyl chloride, and this and polyurethane, have been used as medical synthetic resin materials for soft synthetic resin bags such as blood bags, blood collection bags, blood transfusion bags and catheters for infusion and discharge. Blenders with polybutadiene, acrylonitrile, polyethylene, polypropylene, etc. have been known. However, none of these materials can satisfy the requirements of flexibility, transparency, heat resistance and thermal adhesiveness. Generally, polyvinyl chloride has been added with a plasticizer or the like in order to satisfy these various characteristics and to impart stability and flexibility to the material. However, these additives have a problem in that they are eluted. In addition, for those using medical synthetic resin instruments made of polyethylene or polypropylene as raw materials, those without plasticizer were also provided, but in terms of all of their flexibility, compatibility, and transparency. Satisfactory materials have not been obtained, and there is still a big problem in terms of heat resistance, and the sterilization temperature cannot be raised, which causes the processing time to become longer, and the processing should be performed in a clean atmosphere. Various measures were required in the sterilization process. Further, as the resin having high heat resistance, a resin having a high melting point among thermoplastic resins, for example, polypropylene can be mentioned, but flexibility,
At present, there is a problem of weak impact strength at low temperatures and it is not used at present.

Further, since it has high water vapor and gas permeability,
When used as a storage container for an aqueous solution or the like, a satisfactory medical material has not been provided due to changes in the composition of components due to evaporation of water vapor from the inside and deterioration due to oxidation of the internal solution.

The present invention is to provide a medical device which eliminates these drawbacks.

Generally, it is well known that high-pressure low-density polyethylene is crosslinked by radiation or the like to improve heat resistance. However, it is effective only for the purpose of improving heat resistance, but there is a problem in flexibility. Remain.

On the other hand, Japanese Patent Laid-Open No. 53-85980 discloses a method of radiation-crosslinking a copolymer of vinyl acetate and ethylene to impart heat resistance. Although transparency and heat resistance were satisfactory, there was a problem of odor.

Further, in Japanese Patent Laid-Open No. 4-182165, the density is 0.890 to 0.935 g / cm ³ , and the MFR is
Has been proposed by cross-linking a polyethylene film or sheet having 0.1 to 8 g / 10 minutes in the range of gel fraction 10 to 50% to provide a medical film or sheet having sufficient heat seal strength. The linear low-density polyethylene used here had variations in branching degree distribution and molecular weight distribution, and the effect of improving heat resistance was not sufficient even when crosslinked.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a medical device having excellent transparency, heat resistance and flexibility for discharging or storing body fluids, drugs and the like.

[0009]

Means for Solving the Problems As a result of intensive investigations, the present inventors have found that a molded article using a linear ethylene / α-olefin copolymer having a specific molecular weight distribution and branching degree distribution is heat-resistant. Radiation and / or electron beam irradiation in order to impart the crosslink ratio of 20% or more, transparency and heat resistance, which cannot be achieved by a molded article using a conventional ethylene / α-olefin copolymer, It has been found that a medical device for discharging or preserving body fluids, drugs, etc., which can impart flexibility can be manufactured.

That is, in the present invention, ethylene and a carbon number of 3 to 1 are used.
2, which has a density of 0.850 to 0.920 g / cm ³ , a molecular weight distribution determined by GPC of 3 or less, and a high molecular weight region of 30% by weight fractionated by GPC. Radiation and / or radiation to a molded product obtained by using a linear ethylene / α-olefin copolymer having a ratio of the average number of branches in the low molecular weight region of 30% by weight to the average number of branches of 0.8 or more and 1.2 or less. Alternatively, it is a medical device characterized by being irradiated with an electron beam to have a crosslinking rate of 20% or more.

In order to obtain this molded product, it is necessary to irradiate the resin with radiation and / or an electron beam so that the crosslinking rate is 20% or more in order to impart heat resistance to the resin. In particular, by adopting a crosslinked structure that does not contain any plasticizer with excellent heat resistance, it is possible to obtain a medical device that is excellent in flexibility, transparency, heat resistance, etc. and has no elution of plasticizer or stabilizer. Obtainable. Furthermore, by controlling the crosslinking conditions, acid resistance, alkali resistance, mechanical workability,
It is possible to impart excellent functions such as dimensional stability and rubber elasticity.

Linear ethylene / α-used in the present invention
The olefin copolymer has substantially no branching degree distribution,
It is considered that the branches were uniformly present and uniform cross-linking occurred to effectively improve the heat resistance.

Hereinafter, the present invention will be described in detail.

Linear ethylene / α-used in the present invention
The olefin copolymer is ethylene and α having 3 to 12 carbon atoms.
-A copolymer with an olefin having a density of 0.850
The ratio (Mw) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) determined by GPC at ˜0.920 g / cm ^3.
/ Mn) is 3 or less, and the ratio of the average number of branches in the low molecular weight region 30% by weight to the average number of branches in the high molecular weight region 30% by weight fractionated by GPC is 0.8 or more and 1.2 or less,
According to JIS K6760, the melt index (MFR) measured at 190 ° C. under a load of 2160 g is 0.3 to 50 g / 10 minutes. If the density is out of this range, the flexibility and transparency required for the product cannot be satisfied, and if the ratio of (Mw / Mn) and the number of branches is out of this range, the heat resistance improving effect is insufficient. . Also,
If the MFR is less than 0.3 g / 10 min, the load during extrusion becomes large and molding becomes difficult, and if it exceeds 50 g / 10 min, the strength of the product decreases and it is not suitable for practical use.

In the present invention, (Mw / Mn) and the average number of branches in each region are specifically determined as follows.

Waters 150C ALC / GP
C (column: Tohso GMHHR-H (S), solvent:
GPC using 1,2,4-trichlorobenzene)
By the method, Mw and Mn were measured, and (Mw / Mn) was calculated. The column elution volume was calibrated by the universal calibration method using Tosoh standard polystyrene.

Of the total amount eluted by GPC, the first eluted 30 wt% is the high molecular weight region, the subsequently eluted eluting is the peak molecular weight region, and the last eluted 30 wt% is the low molecular weight region. The molecular weight range. The average number of branches of each molecular weight region component fractionated in this way was calculated as the number of short chain branches per 1000 carbon atoms by connecting FT-IR (1760X manufactured by Perkin Elmer Co., Ltd.) as a detector of the above measuring device. I asked.

Such a linear ethylene / α-olefin copolymer can be produced, for example, by the method disclosed in the following publications.

Japanese Patent Laid-Open Nos. 60-35006 and 6
No. 0-35007, JP-A-60-35008, JP-A-3-163088, and JP-A-61-29.
6008, JP 63-22804, JP 58-19309, JP 63-61010, JP 63-152608, JP 63-
No. 264606, No. 63-280703, No. 64-6003, and No. 1-9511.
No. 0, JP-A-3-62806, JP-A 1-2
59004, JP 64-45406 A, JP 60-106808 A, JP 60-1379 A.
11, JP-A-61-296008, JP-A-63-501369, JP-A-61-221207.
JP, JP-A-2-22307, JP, 2-17
3110, JP-A-2-302410, JP-A-1-129003, JP-A-1-210404, JP-A-3-66710, JP-A-3-707.
No. 10, JP-A-1-207248, JP-A-6
3-222177, JP-A-63-222178, JP-A-63-222179, JP-A 1-1
No. 2407, No. 1-301704, No. 1-319489, No. 3-74412, No. 61-264010, No. 1-27.
5609, JP-A-63-251405, JP-A-64-74202, JP-A-2-41303, JP-A-1-31488, and JP-A-3-565.
08, JP-A-3-70708, JP-A-3-70308
70709, etc.

The method for producing the linear ethylene / α-olefin copolymer which can be used in the present invention will be described below based on the contents thereof. This linear ethylene / α
The olefin copolymer is, for example, an organic transition metal compound (I) containing a cyclopentadienyl derivative, and a compound (II) and / or an organic metal compound (III) which reacts with the organic transition metal compound (I) to form an ionic complex. It can be suitably produced by copolymerizing ethylene with the above-mentioned α-olefin having 3 or more carbon atoms in the presence of a catalyst consisting of

As the α-olefin having 3 to 12 carbon atoms, propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-pentene, 1-hexene, 1-heptene, 1 -Octene, 1-nonene, 1-
Decene, 1-undecene, 1-dodecene, and the like can be given.

The polymerization method used can be exemplified as follows.

The polymerization conditions for the solution polymerization method are as follows. The polymerization temperature is preferably the melting point or higher in consideration of the fact that the copolymer is in a solution state and improving productivity. The upper limit of the polymerization temperature is not particularly limited, but is preferably 300 ° C. or lower in order to suppress a chain reaction that causes a decrease in molecular weight and not to lower the catalyst efficiency. The pressure during polymerization is not particularly limited, but is preferably atmospheric pressure or higher in order to improve productivity.

The polymerization conditions for the high pressure polymerization method are as follows. The polymerization temperature is preferably 120 ° C. or higher in consideration of the fact that the copolymer is in a solution state and improving productivity. Although the upper limit of the polymerization temperature is not particularly limited, it is preferably 300 ° C. or lower in order to suppress the chain transfer reaction that causes a decrease in the molecular weight and not decrease the catalyst efficiency. The pressure during polymerization is not particularly limited,
Polymerization is stably performed in a high-pressure process 200
kgf / cm ² or more is preferable.

In the gas phase polymerization method, the high temperature is not preferable because the copolymer is in a powder state, and it is preferably 100 ° C. or lower. The lower limit of the polymerization temperature is not particularly limited, but is preferably 50 ° C. or higher in order to increase productivity.

The linear ethylene / α-olefin copolymer in the present invention is an additive usually used for polyolefins such as an antioxidant, a weather resistance stabilizer, an antistatic agent, a lubricant and an antiblocking agent, if necessary. May be added.

The linear ethylene / α-olefin copolymer is molded into a sheet or cylinder by extrusion molding, calender molding, blow molding or the like. These are manufactured into a predetermined shape and size by heat sealing, and an injection port and the like are attached. After that, the radiation and / or
Or, it is irradiated with electron beam to crosslink to obtain the intended medical device.

The crosslink density of this medical device can be controlled by the irradiation dose, and generally heat resistance is imparted as the crosslink density progresses.

It has been found that a crosslinking rate of 20% or more meets the purpose of the invention, and when radiation is used, the dose rate is 1 to 15 Mrad, preferably 2 to 10 Mrad.

An example of heat resistance in this case is an ethylene / 1-butene copolymer, which is 60 to 60 in the case of no irradiation.
It was 70 ° C, but it was 1 when the cross-linking rate was 75% by irradiation.
It was confirmed that high-pressure steam sterilization at 25 ° C for 30 minutes was possible.

As described above, the molded article of the present invention withstands autoclave sterilization, which is an essential condition for medical instruments,
In addition to being a material having excellent flexibility, it is possible to provide a hygienic medical device in combination with a feature that does not contain a plasticizer.

Cobalt 60 can be used as a radiation source and a resonant transformation electron beam source can be used as an electron beam source, and the latter can process in a shorter time.

The thus-obtained molded product is used, for example, in a blood bag for blood storage, blood collection, an infusion set, a blood transfusion set, and the like. Generally, these medical devices are merely examples, and the medical devices are not limited thereto as long as they meet the object of the present invention.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

The density was measured according to JIS K6760 by immersing the test piece in hot water at 100 ° C. for 1 hour and then slowly cooling it to room temperature with a density gradient tube kept at 23 ° C.

Crosslinking is performed by E manufactured by Nisshin High Voltage Co., Ltd.
Irradiation was carried out in the air at room temperature using PS-750. The cross-linking rate was calculated by putting the sample in a stainless steel mesh, refluxing it with boiling xylene for 12 hours for extraction, and extracting the extraction residue after drying under reduced pressure as a weight percentage.

The flexibility was evaluated by a tensile tester with a sample width of 10 mm, an initial sample length of 50 mm, and a pulling speed of 50 mm /
Tensile strength was measured in minutes, and tensile strength at an elongation of 5% was measured.

The haze was measured according to ASTM D-1003.

Example 1 Polymerized with a metallocene-type catalyst and having a density of 0.90
0 g / cm ³ , MFR 1.0 g / 10 min, ratio of average number of branches in 30% by weight of low molecular weight fraction to average number of branches of 30% by weight of high molecular weight fraction fractionated by GPC was 1.
1. Using an ethylene / 1-butene copolymer having a molecular weight distribution (Mw / Mn) of 1.8 by GPC, a film having a layer thickness of 200 μm was formed under the following conditions.

To evaluate the appearance of the sample, the bag was filled with pure water and steam sterilized at 125 ° C. for 30 minutes, and the deformation and wrinkle formation were observed.

These evaluations are shown in the following 4 ranks.

⊚: Very good, ◯: Good Δ: Slightly bad, ×: Poor Extruder: Placo single-layer water-cooled inflation molding machine For the odor evaluation of the film, 50 g of the film was cut into 2 cm square, filled in a 500 cc glass tube, sealed, and then heated in an oven at 40 ° C. for 60 minutes. Then, it cooled to room temperature and judged by 10 panelists.

The criteria used by the panelists were as follows: 0: no odor, 1: slight odor, 2: distinct odor, and evaluated by the total value of 10 persons.

Comparative Example 1 Polymerized using a Ziegler type catalyst and having a density of 0.90.
0 g / cm ³ , MFR 1.0 g / 10 min, the ratio of the average number of branches in 30% by weight of the low molecular weight fraction to the average number of branches of 30% by weight of the high molecular weight fraction fractionated by GPC was 5, G
Using an ethylene / 1-butene copolymer having a molecular weight distribution (Mw / Mn) of 5 by PC, a film having a layer thickness of 200 μm was molded under the same conditions as in Example 1.

Comparative Example 2 Produced by the high pressure method, the density was 0.941 g / cm ³ , M
A layer thickness of 200 μm was used under the same conditions as in Example 1, using FR having a content of 1.5 g / 10 min and a vinyl acetate content of 20%.
Film was molded.

The results of the degree of crosslinking and the like in the above Examples and Comparative Examples are summarized in Table 1.

[0047]

[Table 1]

[0048]

EFFECTS OF THE INVENTION A molded product using a linear ethylene / α-olefin copolymer obtained by copolymerizing a specific ethylene and an α-olefin having 3 to 12 carbon atoms obtained by the present invention is irradiated with Medical instruments for discharging or preserving body fluids, chemicals, etc. that have been crosslinked by electron beam irradiation are superior in heat resistance to medical instruments manufactured by conventional methods, and can also satisfy flexibility and transparency. Met.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C08L 23/08 LDD B65D 1/00 A C08L 23:04

Claims (1)

[Claims] 1. A (a) density obtained by copolymerizing ethylene with an α-olefin having 3 to 12 carbon atoms is 0.850 to.
0.920 g / cm ³ , (b) Ratio (Mw / M) of weight average molecular weight (Mw) and number average molecular weight (Mn) determined by GPC (gel permeation chromatography)
n) is 3 or less, and (c) the ratio of the average number of branches of 30% by weight of the low molecular weight region to the number of branches of 30% by weight of the high molecular weight region fractionated by GPC is 0.8 or more and 1.2 or less. A medical device for discharging or storing a body fluid, a drug solution or the like, which is obtained by cross-linking a molded product made of the ethylene-α-olefin copolymer into 20% or more by irradiation with radiation and / or electron beams.