JP5016250B2 - Medical tube composition - Google Patents

Description

The present invention relates to a composition used as a material for medical tubes such as, for example, an infusion set tube, an extension tube, a blood circuit tube, a connecting tube, and a catheter.

The medical tube is required to have flexibility, but when it is further bent, it needs to have bending resistance so as not to bend and block the liquid flowing inside.

Conventionally, a soft vinyl chloride resin has been used as a material for medical tubes. However, since the soft vinyl chloride resin contains a large amount of a plasticizer such as dioctyl phthalate, there is a concern that the plasticizer elutes into blood, body fluids, etc., and is absorbed and accumulated in the body, thereby harming health.
As an alternative to this, the use of styrenic elastomers has recently been studied (
For example, Patent Documents 1-2).

JP 2002-11091 A Japanese Patent Laid-Open No. 2-31991

The styrenic elastomer is sufficiently flexible without adding a plasticizer, but is inferior in rigidity. Therefore, a tube made of the styrenic elastomer is easy to bend when bent. That is, there is no bending resistance.

The present invention provides a styrene elastomer 100 as a means for solving the above conventional problems.
30 parts by mass of an olefin resin other than the ethylene-α-olefin-based resin, which will be described later, has a flexural modulus of 1000 MPa or less , 70 parts by mass or less of an ethylene-α-olefin-based resin, and 70 parts by mass or less of paraffin oil. Ri Na was added to the ethylene -α- olefin resin α- olefin is an alkene having 6 to 10 carbon atoms, some or all of the olefin resin or flexural modulus of 500 MPa 1000 MPa or less, in haze is 30% or less of polypropylene, there is provided at least 20 medical tube composition parts by mass Ru is added to the styrene-based elastomer 100 parts by mass.
The styrene elastomer is desirably a styrene-ethylene-butylene-styrene block copolymer .

[Action]
An olefin resin having a flexural modulus of 1000 MPa or less has appropriate flexibility and rigidity. A tube using an olefin-based resin having a flexural modulus of 1000 MPa or more lacks flexibility as an infusion set tube or the like, and is difficult to correspond to the curved shape of a body tube such as a blood vessel or a ureter, and is small. Even in bending (distortion), a large stress acts and the tube is easily bent. Styrenic elastomers have low stress when stressed, especially compressive stress is applied, and stress relaxation is large, and tubes containing the styrenic elastomer absorb the stress when bending stress is applied and resist the resistance of the olefinic resin. Further improve bendability.
The olefin-based resin imparts rigidity and transparency to the composition of the present invention, and in combination with the styrene-based elastomer, imparts bending resistance to the tube using the composition of the present invention. When the addition amount with respect to a mass part is less than 30 mass parts, the rigidity imparting effect of the olefin resin is not exhibited remarkably, and the transparency is also lowered. A tube made of such a composition has poor bending resistance and becomes opaque or translucent.
Moreover, when the addition amount with respect to 100 parts by mass of the styrene-based elastomer exceeds 100 parts by mass, the tube using such a composition lacks flexibility, and it becomes difficult to correspond to the curved shape of the tube in the body, Even with small bends (strains), a large stress acts and the tube is easily bent.
In order to impart good bending resistance and transparency, the olefin resin is selected from those having a flexural modulus of 500 MPa to 1000 MPa and a haze of 30% or less.
The ethylene-α-olefin resin acts as a compatibilizing agent for improving the compatibility between the styrene elastomer and the olefin resin.
When added in an amount exceeding 100 parts by mass with respect to 0 part by mass, the rigidity of the composition increases.

〔effect〕
In the present invention, a tube having moderately balanced rigidity and flexibility, and thus high bending resistance can be obtained.
The tube has excellent transparency and is extremely useful as a medical tube.

The present invention is described in detail below.
[Styrene elastomer]
The styrene elastomer is a block copolymer having a styrene polymer chain as a hard segment and an olefin polymer chain as a soft segment. The olefin block chain is composed of one or more (co) polymer chains of conjugated diene compounds such as butadiene and isoprene, and unsaturated olefins such as isobutene, pentene and 4-methylpentene-1. Furthermore, when the conjugated diene is used for a part or all of the polymer chain constituting the soft segment, a styrene elastomer obtained by hydrogenating the conjugated diene is also used in the present invention.

Specific examples of the styrene elastomer include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SI).
S), styrene- (butadiene-butylene) -styrene block copolymer (SBBS),
Styrene- (ethylene) -butylene-styrene block copolymer (SEBS), styrene- (butadiene-isoprene) -styrene block copolymer (SBIS), styrene- (
And ethylene-propylene) -styrene block copolymer (SEPS), styrene- (ethylene-ethylene-propylene) -styrene block copolymer (SEEPS), and the like.
A desirable styrenic elastomer for the composition of the present invention is SEBS.
SEBS has low strain when stress is applied (especially compressive stress), large stress relaxation, SE
When a bending stress is applied to a tube made of BS, the tube absorbs the stress and is difficult to bend.
The styrene elastomer preferably has a styrene content of 15 to 25% by mass.

[Olefin resin]
Examples of the olefin resin include those other than the ethylene-α-olefin resin described later, such as polyethylene, polypropylene, ethylene-propylene copolymer, polybutylene, ethylene-butylene copolymer, and propylene-butylene copolymer. One or two or more (co) polymers of alkenes are exemplified. From the viewpoint of imparting bending resistance and transparency to the composition, the flexural modulus is 1000 MPa or less, preferably 500 MPa or more, and haze . Polypropylene resin (PP) of 30% or less is a desirable olefin resin.
Furthermore, in order to improve moldability, it is highly crystalline and has a flexural modulus of 1000 MPa or more and 20
A PP homopolymer of 00 MPa or less may be added.

[Ethylene-α-olefin resin]
The ethylene-α-olefin-based resin is a copolymer of ethylene and an olefin (α-olefin) having a double bond polymerizable at the α-position. Desirable examples of the α-olefin include alkenes having 6 to 10 carbon atoms such as hexene, heptene, octene, nonene, and decene, and most preferable ratio of ethylene: octene is 80:20 to 55: 4.
There is a 5 mass ratio ethylene-octene copolymer.

[Other ingredients]
As other components, for example, paraffin oil for imparting flexibility to the composition, fatty acid compounds such as fatty acid esters and fatty acid amides are used to impart lubricity,
Specifically, lubricants such as stearic acid monoglyceride and erucic acid amide, aromatic amines,
Antioxidants such as hydroquinone and aldehyde amine condensate may be added.
The paraffin oil is added in an amount of 70 parts by mass or less with respect to the composition. If the amount exceeds 70 parts by mass, the composition has insufficient rigidity, and the tube made of this becomes easy to bend.

(Preparation of composition)
Each of the above components is usually charged into a mixer and stirred, and then heat softened and kneaded with a kneader heated to 160 to 200 ° C. to form a resin lump, and then pelletized with a pelletizer.
The composition of the present invention is preferably set to a hardness of 90 or less.

[Tube forming]
The tube is manufactured by using the above pellets and performing extrusion using a single screw extruder. The general dimensions of a medical tube are as follows: inner diameter 2.0-14.0 mm, outer diameter 3.0-15.
It is about 0 mm and a thickness of 0.5 to 5.0 mm.

Examples for more specifically explaining the present invention will be described below.
〔Example〕
Each of the blends shown in Table 1 was stirred with a mixer, heated and softened and kneaded with a kneader heated to 160 to 200 ° C. to form a resin lump, and pellets were prepared with a pelletizer.
Using the pellets, an extruder has an inner diameter of 2.3 mm, an outer diameter of 3.6 mm, and a wall thickness of 0.65.
A mm tube was formed.
Using the above tube, (1) bending resistance, (2) hardness, and (3) haze were measured.
The test method is as follows.

〔Test method〕
(1) Bending resistance
(a) The total length of the tube is 200 mm. As shown in FIG. 1, first, both ends of the tube 1 are overlapped to form a ring shape.
(b) Stack the tubes with tweezers 2 in the direction of the ring from the combined part.
(c) End the test if kinks occur in the ring.
(d) Measure the length (L × 2) of the ring at the position where the bending occurred as shown in FIG. (
(The shorter the L × 2 is, the better the bending resistance is.)
(2) Hardness Measurement was performed according to JIS K 7215. For measurement, ASKER CL-150 manufactured by Kobunshi Keiki Co., Ltd. was used.
(3) Haze Measurement was performed according to JIS K 7136. For the measurement, HAZE GARDII manufactured by Toyo Seiki Manufacturing Co., Ltd. was used.

The results are shown in Table 1.

Referring to Table 1, all the examples of the present invention have a hardness of 90 or less, exhibit good bending resistance, L × 2 <100 mm or less, and have a haze of 50% or less and are transparent. Good appearance.
On the other hand, in Comparative Example 1 in which PP is contained in an amount of 100 parts by mass or more (110 parts by mass), the hardness is 90 or more (93), and it is difficult to cope with bending of blood vessels and the like. In Comparative Example 2 where PP is less than 30 parts by mass (10 parts by mass), the haze is 50% or more (74.1), white turbidity is generated, and the appearance is also deteriorated. In Comparative Example 3 containing no PP, the tube is too flexible, the haze is 50% or more (estimated value 90), white turbidity is generated, and bending resistance is reduced (L × 2 = 108> 10).
0 mm).
In Comparative Example 4 containing paraffin oil in an amount exceeding 80 parts by mass (80 parts by mass), the tube is too flexible and bending resistance deteriorates (L × 2 = 110> 100 mm).
Further, in Comparative Example 5 in which the ethylene-octene copolymer is contained in an amount exceeding 70 parts by mass (80 parts by mass), the bending resistance deteriorates (L × 2 = 110> 100 mm).

Since the composition of the present invention provides a tube suitable for a medical tube that is flexible and has good bending resistance, it is industrially applicable.

1 and 2 are explanatory diagrams of a bending resistance test.
Explanatory drawing of the state before bending Illustration of the state after bending

1 tube

Claims (2)

100 parts by mass of styrene elastomer, 30 to 100 parts by mass of olefin resin other than ethylene-α-olefin resin, which will be described later, having a flexural modulus of 1000 MPa or less , 70 parts by mass or less of ethylene-α-olefin resin , paraffin oil Ri Na was added to 70 parts by mass or less,
The α-olefin of the ethylene-α-olefin resin is an alkene having 6 to 10 carbon atoms,
1000MPa part or all flexural modulus 500MPa or more of the above-mentioned olefin resin or less is 30% or less of polypropylene in haze, and wherein Rukoto least 20 parts by weight is added to the styrene-based elastomer 100 parts by weight A medical tube composition. The medical tube composition according to claim 1, wherein the styrene elastomer is a styrene-ethylene-butylene-styrene block copolymer.

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