JPH0557018A - Medical instrument - Google Patents

Abstract

PURPOSE:To reduce the slide resistance of a medical instrument such as a disposable syringe, and prevent an adverse effect on a human body by forming a slide member with a thermoplastic elastomer layer, and covering a section with a thermoplastic synthetic resin layer having a small dynamic friction coefficient and containing a lubrication ingredient, where in contact with the inner side of a cylindrical section. CONSTITUTION:A gasket 3 fitted as a slide member to the end 2a of a plunger 2 comprising high density polyethylene or the like, has a body formed with a thermoplastic elastomer layer 30 such as SBS, etc. A slidable contact section where the gasket 3 is in contact with the inner side of an outer cylinder 1, is covered with a thermoplastic synthetic resin layer 31 of 1 to 500mum thickness having a small dynamic friction coefficient, for example, with polytetrafluoroethylene or the like. Furthermore, the layer 31 is made to contain 0.1 to 10wt.% of a lubrication ingredient such as silicone oil.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a medical device,
In particular, it relates to a disposable syringe.

[0002]

2. Description of the Related Art A syringe is composed of an outer cylinder (syringe body),
It is composed of a plunger (presser) inserted into the outer cylinder and a gasket attached to the tip of the plunger.
As a material of the conventional disposable syringe, polypropylene, poly (4-methylpentene-1), etc. are generally used for the outer cylinder and the pusher, and the gasket is made of vulcanized rubber or thermoplastic to maintain airtightness. An elastic body such as an elastomer is used.

In order to maintain the airtightness of the gasket, the outer diameter of the gasket is required to be larger than the inner diameter of the outer cylinder, and the gasket is strongly pushed into the outer cylinder so that the entire circumference is in close contact with the inner peripheral surface of the outer cylinder. To do. Therefore, unless the sliding surface of the gasket is lubricated, the frictional resistance is considerably increased, and the pusher cannot be smoothly pushed and pulled. Therefore, a lubricating oil such as silicone oil is applied to the inner surface of the outer cylinder to reduce the frictional resistance.

However, when the lubricating oil is applied in this manner, the lubricating oil separated into fine particles flows out into the liquid content of the syringe. Therefore, for example, when the syringe is used as a drug administration device for the human body, use of the lubricating oil is not preferable.

On the other hand, instead of such a method of applying a lubricating oil, as in the gasket disclosed in Japanese Unexamined Patent Publication No. 64-85665, the portion of the gasket which comes into contact with the syringe body has a small dynamic friction coefficient. There is also a structure in which a resin layer is provided to reduce sliding resistance. With such a configuration, the plunger can be pushed and pulled, but the sliding resistance is slightly higher than the conventional disposable syringe coated with lubricating oil, and the operation to finely adjust the pushing amount of the plunger can be performed. It was a little difficult, and it was not enough to push and pull the plunger smoothly.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a medical device which has less adverse effects on the human body and has a smaller sliding resistance between the sliding member and the tubular member.

[0007]

Such an object is achieved by the present invention described below. That is, (1) a medical device comprising a member having a tubular portion and a sliding member that slides in close contact with the inner wall surface of the tubular portion, wherein the sliding member is a thermoplastic elastomer layer. And a thermoplastic synthetic resin layer having a low dynamic friction coefficient coated on the thermoplastic elastomer layer at a position in contact with the inner wall surface of the tubular portion, the thermoplastic synthetic resin contains a lubricating component. A medical device characterized by being present.

(2) The medical device according to the above (1), wherein the thermoplastic synthetic resin is a mixture of ultra-high molecular weight polyethylene and a lubricating component.

(3) The medical device according to the above (1) or (2), wherein the lubricating component is silicone oil.

(4) The medical device according to any one of the above (1) to (3), wherein the content of the lubricating component in the thermoplastic synthetic resin is 0.1 to 10% by weight.

(5) The thermoplastic synthetic resin layer having a low dynamic friction coefficient has a thickness of 1 to 500 μm.
The medical device according to any one of (4).

(6) The medical device according to any one of (1) to (5) above, wherein the member having the tubular portion is an outer cylinder of a syringe, and the sliding member is a gasket of the syringe.

[0013]

When the sliding member slides in the tubular portion of the member, the thermoplastic synthetic resin layer in the sliding contact portion is pressed against the inner wall surface of the tubular portion by the thermoplastic elastomer layer to make sliding contact. At this time, due to the lubricating component mixed in the thermoplastic synthetic resin, the coefficient of dynamic friction between the thermoplastic synthetic resin and the inner wall surface decreases, and the sliding resistance of the sliding member decreases. For this reason, the sliding of the sliding member is smooth, and the operation is easy, so that the accurate operation can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a medical instrument of the present invention, a syringe will be described below as a typical example, and a detailed description will be given based on a configuration example shown in the accompanying drawings. FIG. 1 is a vertical cross-sectional view showing a configuration example of a syringe according to the present invention.

The syringe shown in the figure comprises an outer cylinder 1 which is a member having a cylindrical portion, and a plunger 2 which is inserted into the outer cylinder 1.

As the constituent material of the outer cylinder 1, for example, a transparent hard resin such as polypropylene, polystyrene, polycarbonate, poly (4-methylpentene-1), methacrylic resin, polyethylene terephthalate, AS resin or the like is used. The above-mentioned polyethylene terephthalate hardly changes in physical properties due to γ-ray sterilization, has high transparency, and has good slidability, and is particularly preferable as a constituent material of the outer cylinder.

As the constituent material of the plunger 2, for example, a hard resin such as high density polyethylene, polypropylene, polystyrene, poly (4-methylpentene-1), polyethylene terephthalate or the like is used.

As in the conventional case, the outer cylinder 1 has a liquid outlet portion 1a which can be taper-fitted (may be screwed) with a hub of a needle tube assembly (not shown) at the tip and has a base end. It is open and has a shape having a flange 1b.

The plunger 2 is cylindrical (or cylindrical,
Alternatively, the plate-shaped member may have a cross-sectional shape crossed in a cross shape), and the distal end portion 2a is closed and the base end has a pressing portion 2b, which is a cylindrical member.

A gasket 3 as a sliding member is attached to the tip 2a of the plunger 2. The gasket 3 has an outer diameter slightly larger than the inner diameter of the outer cylinder 1, and is pushed into the outer cylinder 1 from the base end side to adhere to the inner wall surface.
It is designed to be airtight.

As the constituent material of the thermoplastic elastomer layer 30 constituting the main body of the gasket 3, those manufactured by injection molding a thermoplastic elastomer or those manufactured by vulcanization press molding of raw rubber may be used. .. Thermoplastic elastomers include SBS type, SEBS type, EP
At least one of a system, a polyester system, and a polyurethane system can be used. Preferably, SEBS system,
At least one of EP systems is used. Further, as the vulcanized rubber, at least one of butyl rubber, SBR, EPR, NBR, natural rubber, isoprene rubber, chloroprene rubber, and fluororubber can be used.

The compression set (JIS K-630) of the gasket body composed of the above thermoplastic elastomer.
In 1), it is 60% or less under the conditions of 70 ° C. and 22 hours.
It is preferably 50% or less. When the compression set is 60% or more, the gasket progresses to be deformed so that the diameter of the gasket becomes equal to the inner diameter of the outer cylinder over time, and when the gasket is slid, the sliding contact portion separates from the outer cylinder 1 and the airtightness is improved. Because I cannot keep it. The rubber hardness (JIS K-6301) of the material used for the gasket body is JIS-
A is preferably 35 ° to 85 °. Above 85 °,
Assembling the syringe becomes difficult, and if it is smaller than 35 °,
This is because it is deformed during sliding and becomes difficult to slide. Further, the desirable rubber hardness is 40 ° to 70 °. As the thermoplastic elastomer used for the material of the gasket main body, an SBS system having the above compression set and rubber hardness,
At least one of SEBS-based and EP-based copolymers is desirable.

The gasket body has a mushroom-like appearance and has a recessed hole 32 for accommodating and coupling the tip 2a of the plunger 2. As shown in FIG. 2, the thermoplastic synthetic resin layer 31 having a low dynamic friction coefficient is provided at the sliding contact portion where the gasket 3 is in sliding contact with the inner wall surface of the outer cylinder 1.
Is covered.

This thermoplastic synthetic resin is, for example, polytetrafluoroethylene, polyvinylidene fluoride, perchloroalkoxy side chain-containing polytetrafluoroethylene,
Lubricating component for polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinyl fluoride ethylene-tetrafluoroethylene copolymer, high density polyethylene, ultra high molecular weight polyethylene, or at least one of these Is a mixture of.

Examples of the lubricating component include silicone oils, fatty acid amide lubricants, liquid paraffin, hydrocarbon lubricants such as polyethylene wax, metal soaps, and those containing at least one of these.

If the thermoplastic synthetic resin layer 31 is too thick, the hardness of the synthetic resin itself is high, and the hardness of the covered portion becomes too high, so that the resin layer 31 cannot adhere to the inner wall of the outer cylinder 1. .. Therefore, the airtightness inside the syringe cannot be maintained. Therefore, the thermoplastic synthetic resin layer 31
Is preferably thin, preferably 500 μm or less, preferably 100 μm or less, and more preferably 50 μm or less.

Further, the thermoplastic synthetic resin layer 31 preferably has a coefficient of friction with steel of 0.5 or less in terms of sliding resistance. In the present invention, since the thermoplastic synthetic resin contains a lubricating component, even a synthetic resin having a relatively large coefficient of friction against steel can be used.

The sliding resistance is defined as follows. That is, change the plunger from the maximum scale to the maximum scale of 1
The stress when moving at a speed of 100 mm / min up to 0% was measured by a compression tester, and is the average stress (sliding resistance value) at that time.

The adhesive strength of the thermoplastic synthetic resin layer 31 to the thermoplastic elastomer layer 30 is determined by a cross-cut test (JI
It is preferably 70/100 to 100/100 in SD-0202). Further, preferably, 80/10
0 to 100/100, and the adhesive strength is 70/10
When it is less than 0, the bonding strength between the thermoplastic synthetic resin layer 31 and the thermoplastic elastomer layer 30 is weak, so that the gasket 3
This is because the thermoplastic synthetic resin layer 31 may be peeled off from the thermoplastic elastomer layer 30 when sliding.

When the above thermoplastic synthetic resin is mixed with, for example, silicone oil, about 0.1 to 10% by weight,
It is preferable to mix them at a ratio of about 0.2 to 8% by weight. This is because if the mixing ratio is smaller than this range, a sufficient lubricating action cannot be obtained, and if it is larger than this range, vacuum forming as described later becomes difficult. The lubricating component can be added as a plasticizer.

As shown in FIG. 3, the structure of the gasket 3 is such that the thermoplastic synthetic resin layer 31 covers the entire outer peripheral surface of the gasket main body 30 or covers only the sliding contact portion. Good. With such a configuration, it is possible to further reduce the outflow amount of the lubricating component from the thermoplastic synthetic resin layer 31.

In the method of manufacturing the gasket 3 described above, ultra high molecular weight polyethylene is used as the thermoplastic synthetic resin described above, the lubricating component to be mixed is silicone oil, and the constituent material of the thermoplastic elastomer layer 30 is SEB.
The case where the S system is used will be described as an example.

5% by weight of silicone oil is added to the ultra high molecular weight polyethylene to form a sheet 5 having a thickness of about 50 to 100 μm.

As shown in FIGS. 4 and 5, the sheet 5 is placed on a mold 6 and formed into a gasket shape by vacuum forming. Next, the nozzle 7 is inserted into the mold 6 to which the sheet 5 is attached, and as shown in FIG. 6, the molten constituent material of the thermoplastic elastomer layer 30 is injected. Here, the shape of the nozzle 7 is substantially the same as that of the tip 2a of the plunger, and the nozzle 7 forms a recessed hole 32 to which the plunger is connected.

As another method, as shown in FIG. 7, two-color molding in which the thermoplastic synthetic resin layer 31 is molded by injection molding may be used.

Although the configuration example described above has been described by taking a syringe as an example, the present invention is not limited to such a case, and a member having a tubular portion and a sliding member that slides in close contact with the inner wall surface of the tubular portion. As long as it is a medical device comprising:

[0037]

[Examples] With respect to syringes having the following specifications, the sliding resistance of the gasket and the elution amount of the lubricating component were measured and compared.

Inner diameter of tubular portion of outer cylinder: 13.0 mm Overall length of tubular portion: 60 mm Material of outer cylinder: polypropylene Outer diameter of gasket: 13.5 mm

Under the above conditions, the above-mentioned values were measured using the following gaskets. <Comparative Example 1> SEBS-based gasket is used as the constituent material,
About 3 mg of silicone oil was applied to the inner tip of the tubular portion of the outer tube.

Comparative Example 2 Material of Thermoplastic Elastomer: Material of SEBS Thermoplastic Synthetic Resin Layer: Ultra High Molecular Weight Polyethylene The thermoplastic synthetic resin layer covers the entire outer peripheral surface of the gasket body and its thickness. Was about 40 μm on average.

Example 1 Thermoplastic Elastomer Constituent Material: SEBS Thermoplastic Synthetic Resin Layer Material: Ultra High Molecular Weight Polyethylene However, the content of silicone oil in the thermoplastic synthetic resin layer is 5% by weight. As shown in FIG. 2, the layer covers the entire outer peripheral surface of the gasket body, and its thickness is about 40 μm on average. The measurement results are shown in Table 1.

[0042]

[Table 1]

Here, the outflow property of the lubricating component is as follows: 5 ml of water is sucked into the syringe, 1 ml of air is further sucked, the mixture is mixed 10 times by inversion, and the diameter per 1 ml of the discharged liquid is 2
The number of fine particles having a size of μm or more was measured.

Further, with respect to the sliding resistance of the gasket, from the plunger of 5 ml to the scale of 0.5 ml, 1
The stress when moving at a speed of 00 mm / min was measured by a compression tester, and the average stress (sliding resistance value) at that time was obtained.

As a result of the above measurement, it was found that the present invention had a sufficiently small sliding resistance and the outflow of the lubricating component was sufficiently smaller than that in the case where the conventional lubricant was applied.

[0046]

As described above, according to the medical device of the present invention, there are advantages that the human body is not adversely affected and the sliding member slides smoothly. Therefore, there is an advantage that the instrument can be operated easily and the instrument can be operated accurately.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the configuration of a syringe.

FIG. 2 is a vertical sectional view of a gasket.

FIG. 3 is a vertical sectional view showing another embodiment of the gasket.

FIG. 4 is a cross-sectional view of a mold showing a state before molding in a method of molding a thermoplastic synthetic resin layer into a gasket shape by vacuum forming.

FIG. 5 is a cross-sectional view of a mold showing a state after molding in a method of molding a thermoplastic synthetic resin layer into a gasket shape by vacuum forming.

FIG. 6 is a cross-sectional view of a mold showing a state where a gasket body is molded by injection molding after molding a thermoplastic synthetic resin layer into a gasket shape.

FIG. 7 is a cross-sectional view of a mold showing a state where a thermoplastic synthetic resin layer is molded by a two-color molding method.

[Explanation of symbols]

 1 Outer cylinder 1a Liquid outlet part 1b Flange 2 Plunger 2a Tip part 2b Pressing part 3 Gasket 30 Gasket body 31 Thermoplastic synthetic resin layer 32 Recessed hole 5 Sheet 6 Mold 7 Nozzle 8 Nozzle

Claims (6)

[Claims] 1. A medical device comprising a member having a tubular portion and a sliding member that slides in close contact with the inner wall surface of the tubular portion, wherein the sliding member is a thermoplastic elastomer layer. And a thermoplastic synthetic resin layer having a low dynamic friction coefficient coated on the thermoplastic elastomer layer at a position contacting at least the inner wall surface of the tubular portion, the thermoplastic synthetic resin contains a lubricating component. A medical device characterized by being present. 2. The medical device according to claim 1, wherein the thermoplastic synthetic resin is a mixture of ultra-high molecular weight polyethylene and a lubricating component. 3. The medical device according to claim 1, wherein the lubricating component is silicone oil. 4. The content of the lubricating component with respect to the thermoplastic synthetic resin is 0.1 to 10% by weight.
The medical device according to any one of 3 above. 5. The medical device according to claim 1, wherein the thermoplastic synthetic resin layer having a low dynamic friction coefficient has a thickness of 1 to 500 μm. 6. The medical device according to claim 1, wherein the member having the tubular portion is an outer cylinder of a syringe, and the sliding member is a gasket of the syringe.