JP2892617B2 - Syringe stopper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plug for a syringe which is slidably inserted into an outer cylinder for a syringe and is used when administering a drug solution in the outer cylinder to a human body or an animal.

[0002]

2. Description of the Related Art A syringe has a syringe outer cylinder, a stopper, and a plunger as basic components. When a medicinal solution is administered, the stopper is pushed by the plunger to push out the medicinal solution held in the outer cylinder. The outer cylinder and the stopper are required to have liquid-tightness, air-tightness, and slidability as physical characteristics, including usage modes such as oblique pulling when sucking a chemical solution and oblique pushing during extrusion. As the outer cylinder, a glass outer cylinder and a plastic outer cylinder are known. Usually, the glass outer cylinder is used for a type also serving as a chemical solution container, and the plastic outer cylinder is used for a disposal type. Regardless of the outer cylinder, its inner diameter, linearity of the inner wall, smoothness, roundness, etc.
Mechanical variability is inevitable.

[0003] On the other hand, in order to absorb variations in the mechanical shape of the outer cylinder, elastic plugs mainly made of an elastic material such as rubber or thermoplastic elastomer are widely used. Conventionally, this elastic plug has been used in the form of a simple column, a tapered column having a diameter gradually reduced toward the rear side, or an annular projection provided before and after these columns or tapered columns. . However, according to the analysis of the present inventor, these conventional elastic plugs have physical properties,
For example, there is room for improvement in slidability and airtightness.

[0004] In particular, the surface of the laminated stopper provided by the present applicant, ie, the elastic stopper, is selected from the group consisting of a tetrafluoroethylene resin film, an ethylene / tetrafluoroethylene resin film and an ultrahigh molecular weight polyethylene resin film. In a stopper covered with one laminated layer, the elastic followability tends to be hindered by the laminated layer. Therefore, there is a demand for improving the physical characteristics. The laminated stopper is a silicone-free stopper and there is no need to apply silicone oil as a lubricant to the sliding part. Conventional stoppers coated with silicone oil have the problems that the silicone oil may be mixed with a chemical solution and cause contamination of fine particles.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an elastic stopper for a syringe, particularly an elastic stopper having excellent physical properties, particularly airtightness and slidability. Another object of the present invention is to obtain a plug having a similar physical property even in a laminated stopper.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a syringe plug having a column which is slidably inserted into a syringe barrel and has a rotationally symmetrical shape with respect to the axis of the syringe barrel. It has the largest diameter part, and the R of the cross section around the tip part is
The diameter of the rear end of the column is smaller than the inner diameter of the outer cylinder when inserted into the outer cylinder of the syringe, and is not in contact with the outer cylinder. When the radius of the cross section around the distal end is reduced as above, the increase in sliding resistance can be suppressed, and since the chemical does not enter around the distal end of the stopper, a "pool" of the chemical occurs. Without giving it a feeling of trust and security. When the rear end portion is smaller than the inner diameter of the outer cylinder, knocking does not occur particularly during the pulling operation, and favorable operability is obtained.

The column has a first reduced diameter portion from the front end portion to the middle portion, and a second reduced diameter portion from the middle portion to the rear end portion. By making the diameter smaller than the diameter of the first reduced diameter portion, the rear end can be easily brought into non-contact with the syringe barrel. When the contour lines in the cross section passing through the axis of the column of the first reduced diameter portion and the second reduced diameter portion are respectively composed of straight lines and circular arcs, the degree of reduction of the second reduced diameter portion can be easily changed to the first reduced diameter portion. It can be larger than the degree of diameter reduction. The degree of diameter reduction refers to the inclination when the contour is a straight line, and the ratio between the diameter difference between the front end and the rear end and the axial length when the contour is an arc.

[0008] In the plug for a syringe of the present invention, at least the outer diameter of the first reduced diameter portion in the free state is made larger than the inner diameter of the outer cylinder of the syringe, and is elastically deformed when inserted into the outer cylinder. The amount of elastic deformation is such that the inner diameter of the syringe barrel is 7.0 to 32.0 m.
When m, the distance is preferably 3/100 to 15/100 mm. The taper representing the degree of diameter reduction of the first diameter-reduced portion may be set to 0.5 to 3.0 degrees depending on the size (diameter) of the stopper.

[0009] Further, the ratio of the axial length of the first reduced diameter portion to the second reduced diameter portion is 0.6 to 0.9: 1, and the first reduced diameter portion is inserted into the syringe barrel. When the diameter portion contacts the syringe barrel and the second reduced diameter portion does not, a favorable balance between slidability and airtightness can be obtained.

Further, when a peripheral annular flat portion substantially perpendicular to the axis and a flat central conical portion having a high axial portion are formed on the distal end surface of the column, the slidability during a pulling operation can be particularly improved. I knew I could do it.

A female screw hole for screwing the plunger is formed at the rear end of the shaft portion of the column. The minimum diameter of the rear end portion is such that the minimum thickness from the female screw hole to the outer peripheral surface of the column is 1.0 to 4.0.
mm.

The plug for a syringe according to the present invention is particularly preferably a silicone-free plug, that is, an elastic plug made of an elastic material; a tetrafluoroethylene resin film, ethylene tetratetrafluoroethylene resin film formed on the surface of the elastic plug. A laminated layer selected from the group consisting of a fluoroethylene resin film and an ultra-high molecular weight polyethylene resin film;

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. 1 and 2 show a first embodiment in which the present invention is applied to a laminated stopper. The laminated stopper 10 is an elastic stopper base 1 made of rubber or a thermoplastic elastomer.
2, one laminated layer 11 selected from the group consisting of a tetrafluoroethylene resin film, an ethylene / tetrafluoroethylene resin film and an ultrahigh molecular weight polyethylene resin film on at least the outer peripheral surface and the distal end surface.
Is a slip stopper coated with. The thickness of the laminate layer 11 is preferably about 0.001 to 0.2 mm. The laminated stopper 10 is provided with a threaded hole 13 of a plunger 41 at a shaft portion thereof, and is slidably inserted into the syringe barrel 42 by the plunger 41.

The laminated stopper 10 is formed of a column having a rotationally symmetric shape about the axis 10x, and has a first reduced diameter portion 14 and a second reduced diameter portion 15. The first reduced diameter portion 14 has a gradually reduced diameter from the front end portion A to the middle portion B, and the second reduced diameter portion 15 has a gradually reduced diameter from the middle portion B to the rear end portion C. The outer diameter of the first reduced diameter portion 14 in the free state is larger than the inner diameter of the syringe outer cylinder 42, and elastically deforms when inserted into the outer cylinder. The difference between the two is 3/100 to 1
It is good to be about 5/100 mm.

Axis 1 of first reduced diameter portion 14 and second reduced diameter portion 15
In this embodiment, the contour cut by the cross section passing through 0x is such that the first reduced diameter portion 14 is a straight line, the second reduced diameter portion 15 is an arc, and the taper of the first reduced diameter portion 14 is smooth. The radius of curvature of the arc of the second reduced diameter portion 15 is determined in consideration of the diameter and length of the stopper 10 in the range of 0.5 ° to 3.0 °. In order to prevent this, the diameter of the second reduced diameter portion is determined to be larger than the diameter of the first reduced diameter portion. If the taper of the first reduced diameter portion 14 is smaller than 0.5 °, it is difficult to sufficiently increase the contact (sliding) pressure at the distal end portion. The non-uniformity of the deformation amount of the outer cylinder 42 in the length direction of the 14 is too large, and it is difficult to obtain smooth sliding characteristics. If the degree of diameter reduction of the second diameter reducing part 15 is larger than the degree of diameter reduction of the first diameter reducing part 14, it is difficult to make the whole non-contact with the syringe barrel 42, and good sliding characteristics can be obtained. I can't. Further, as described above, the rear end of the second reduced diameter portion 15 is liable to generate burrs at the time of manufacturing, and even if burrs are generated, the rear end of the second reduced diameter portion 15 (laminate slip stopper 10) is not easily formed. In order not to make contact with the syringe barrel 42, the degree of diameter reduction is made larger than that of the first reduced diameter portion than that of the second reduced diameter portion. That is, the rear end portion C of the second reduced diameter portion 15 has a sufficiently small diameter by the second reduced diameter portion 15 so as not to come into contact with the outer cylinder 42 when inserted into the syringe outer cylinder 42.

The cross section R of the corner portion at the tip end portion A of the first reduced diameter portion 14 is very small, 5/100 to 10/1.
00 mm. In addition, a flat truncated cone 16 having a high shaft portion is formed on the distal end surface of the lamination stopper 10.

As described above, when the maximum diameter of the laminated stopper 10 is provided at the distal end and the cross section R of the periphery of the distal end (of the first reduced diameter portion 14) is reduced, smooth sliding characteristics can be obtained. The reason is that the diameter of the first reduced diameter portion 14 in the free state is larger than the inner diameter of the syringe barrel 42, that is, so-called plus fitting. At this time, if the radius of the distal end portion is large as in the conventional case, the contact area with the syringe barrel 42 at the R portion becomes large. On the other hand, when the tip R is reduced as in the above range, the contact area at the R portion is reduced, and as a result, it is inferred that excellent sliding characteristics can be obtained. Further, when this R is reduced as above, the chemical does not enter the periphery of the top end of the laminated stopper 10, so that the liquid does not “accumulate” and a sense of reliability and security can be provided.

If the rear end is smaller than the inner diameter of the outer cylinder,
In particular, the knocking phenomenon does not occur during the pulling operation. This is because the rear end of the second reduced diameter portion 15 is liable to generate burrs during manufacturing, and even if burrs are generated, the second reduced diameter portion 1
By preventing the rear end of the 5 (laminated stopper 10) from coming into contact with the syringe outer cylinder 42, occurrence of knocking can be suppressed and smooth sliding characteristics can be obtained.

On the other hand, the diameter of the rear end of the laminated stopper 10 is
The minimum thickness from the screw hole 13 to the outer peripheral surface of the laminated stopper can also be specified. This minimum thickness is 1.0-
It is 4.0 mm.

The ratio of the axial lengths (L1 and L2) of the first reduced diameter portion 14 and the second reduced diameter portion 15 is 0.6: 1 to 0.5.
9: 1. If L2 is too short relative to L1,
The burrs may come into contact with the syringe barrel 42 and hinder the slidability. If L1 is too long, the slidability also increases, and the operability and the insertability of the plug with a machine deteriorate. Become.

FIG. 3 shows another embodiment of a syringe stopper according to the present invention. This embodiment is characterized by the shape of the tip of the laminated stopper 10 compared to the above embodiment. The distal end of the laminated stopper 10 is composed of a peripheral annular flat portion 17 that is substantially perpendicular to the peripheral axis 10x, and a flat central frustoconical portion 16 having a high central shaft portion. This embodiment is particularly excellent in sliding characteristics during a pulling operation.

[0022]

As described above, according to the present invention, it is possible to obtain a stopper for a syringe having excellent physical properties, and particularly, having a good balance between hermeticity and slidability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a state in which a syringe stopper according to the present invention is combined with an outer cylinder and a plunger.

FIG. 2 is an enlarged cross-sectional view of the single stopper for a syringe of FIG. 1;

FIG. 3 is a cross-sectional view showing another embodiment of the syringe stopper according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Laminated stopper (elastic stopper) 10 'Sliding element 10' 10x Axis 11 Laminating layer 12 Elastic stopper base 13 Screw hole 14 First reduced diameter part 15 Second reduced diameter part 15 'Small diameter part 16 Conical frustum 17 Peripheral annular flat surface 41 Plunger 42 Syringe barrel

Claims (8)

(57) [Claims] Claims: 1. A syringe is slidably inserted into a syringe barrel.
In a stopper for a syringe comprising a column having a rotationally symmetrical shape with respect to the axis of the syringe barrel, the column has a maximum diameter portion at a distal end, and R of a cross section around the distal end is 5/100 to 10 /. 100mm
A rear end diameter of the column is smaller than an inner diameter of the outer cylinder when inserted into the outer cylinder of the syringe, and is not in contact with the outer cylinder. 2. The column according to claim 1, wherein the column has a first reduced diameter portion from the front end to the intermediate portion, and a second reduced diameter portion from the intermediate portion to the rear end. The stopper for a syringe, wherein the degree of diameter reduction of the part is greater than the degree of diameter reduction of the first diameter reducing part. 3. The plug for a syringe according to claim 2, wherein the contour of the cross section passing through the axis of the column is such that the first reduced diameter portion is a straight line and the second reduced diameter portion is a circular arc. 4. The stopper for a syringe according to claim 3, wherein the taper of the first reduced diameter portion is 0.5 ° to 3.0 °. 5. A syringe according to claim 1, wherein the distal end surface of the column has a peripheral annular flat portion substantially perpendicular to the axis and a flat central conical portion with a high axial portion. Stopper. 6. The column according to claim 1, wherein a female screw hole for screwing a plunger is formed at a rear end of the shaft of the column, and a minimum thickness from the female screw hole to the outer peripheral surface of the column is formed. Is a stopper for a syringe having a diameter of 1.0 to 4.0 mm. 7. The method according to claim 1, wherein the ratio of the axial length of the first reduced diameter portion to the second reduced diameter portion is:
0.6 to 0.9: 1, wherein the first reduced-diameter portion is in contact with the syringe outer cylinder and the second reduced-diameter portion is non-contact when inserted into the syringe outer cylinder. 8. The stopper for a syringe according to claim 1, wherein the stopper for the syringe is an elastic stopper made of an elastic material; and a tetrafluoroethylene resin film formed on the surface of the elastic stopper. And one laminated layer selected from the group consisting of an ethylene / tetrafluoroethylene resin film and an ultrahigh molecular weight polyethylene resin film.