Vial rubber stopper

Abstract

Provided is a vial rubber stopper using multiple types of rubber to prevent the vial rubber stopper from being scraped and from sticking to a presser plate. The vial rubber stopper includes: a cap portion having a flange; a piercing area formed to have a recess at a top surface of the cap portion and configured to traverse longitudinally the cap portion in an axial direction from the recess to a bottom surface of the cap portion; and a leg portion formed on the bottom surface of the cap portion in a way of extending downward and located outside the piercing area with respect to an axial center of the cap portion. The piercing area is formed of rubber having rubber hardness from 20 to 35, and the top surface other than the recess of the cap portion is formed of rubber having rubber hardness from 58 to 90.

Claims

1. A vial rubber stopper comprising: a cap portion having a top surface with at least one opening, a bottom surface and a flange; at least one piercing portion recessed downwardly from the top surface of the cap portion to form a recess, said recess having a sidewall inwardly tapered from the top surface of the cap portion toward a central axis of the at least one piercing portion, the at least one piercing portion being configured to traverse said cap portion from the at least one opening to the bottom surface of the cap portion in an axial direction along a central axis of the cap portion; and a leg portion extending downward from the bottom surface of the cap portion and having a recess wider than the top surface of the at least one piercing portion, wherein the top surface of the cap portion is formed of rubber having a Type A rubber hardness from 58 to 90, wherein the at least one piercing portion, the bottom surface of the cap portion and the leg portion are formed of rubber having a Type A rubber hardness from 20 to 35, wherein the cap portion, the at least one piercing portion and the leg portion are unitarily formed as one piece, and wherein the flange of the cap portion is the entire portion, which extends out of an outer diameter of the leg portion, of the cap portion, and includes a first portion made of the rubber having the Type A rubber hardness from 58 to 90 and a second portion made of the rubber having the Type A rubber hardness from 20-35.

2. A vial rubber stopper comprising: a cap portion having a top surface with at least one opening, a bottom surface and a flange; at least one piercing portion recessed downwardly from the top surface of the cap portion to form a recess, said recess having a sidewall inwardly tapered from the top surface of the cap portion toward a central axis of the at least one piercing portion, the at least one piercing portion being configured to traverse said cap portion from the at least one opening to the bottom surface of the cap portion in an axial direction along a central axis of the cap portion; and a leg portion extending downward from the bottom surface of the cap portion and having a recess wider than the top surface of the at least one piercing portion, wherein the cap portion, the at least one piercing portion and the leg portion are unitarily formed as one piece, wherein the top surface of the cap portion and a side surface of the flange are formed of rubber having a Type A rubber hardness from 58 to 90, the flange being the entire portion, which extends out of an outer diameter of the leg portion, of the cap portion, and wherein the at least one piercing portion, the bottom surface of the cap portion and the leg portion are formed of rubber having a Type A rubber hardness from 20 to 35.

3. A vial rubber stopper comprising: a cap portion having a top surface with at least one opening, a bottom surface and a flange; at least one piercing portion recessed downwardly from the top surface of the cap portion to form a recess, said recess having a sidewall inwardly tapered from the top surface of the cap portion toward a central axis of the at least one piercing portion, the at least one piercing portion being configured to traverse said cap portion from the at least one opening to the bottom surface of the cap portion in an axial direction along a central axis of the cap portion; and a leg portion extending downward from the bottom surface of the cap portion and having a recess wider than the top surface of the at least one piercing portion, wherein the cap portion, the at least one piercing portion and the leg portion are unitarily formed as one piece, wherein the top surface of the cap portion and the flange are formed of rubber having a Type A rubber hardness from 58 to 90, the flange being the entire portion, which extends out of an outer diameter of the leg portion, of the cap portion, and wherein the at least one piercing portion and the leg portion are formed of rubber having a Type A rubber hardness from 20 to 35.

4. The vial rubber stopper according to claim 1, wherein the top surface of the cap portion includes two openings, the at least one piercing portion includes two piercing portions, each corresponding to one of the two openings, and each of the two piercing portions includes a top surface narrower than the corresponding opening.

5. The vial rubber stopper according to claim 2, wherein the top surface of the cap portion includes two openings, the at least one piercing portion includes two piercing portions, each corresponding to one of the two openings, and each of the two piercing portions includes a top surface narrower than the corresponding opening.

6. The vial rubber stopper according to claim 3, wherein the top surface of the cap portion includes two openings, the at least one piercing portion includes two piercing portions, each corresponding to one of the two openings, and each of the two piercing portions includes a top surface narrower than the corresponding opening.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 illustrates a vial rubber stopper according to an embodiment of the present invention, in which (b) is a view of a top surface and (a) is a schematic cross-sectional view taken along a line I-I in (b);

(2) FIG. 2 illustrates a vial rubber stopper according to another embodiment of the present invention, in which (b) is a view of a top surface and (a) is a schematic cross-sectional view taken along a line II-II in (b);

(3) FIG. 3 is a longitudinal sectional view of a vial rubber stopper according to another embodiment of the present invention;

(4) FIG. 4 is a longitudinal sectional view of a vial rubber stopper according to another embodiment of the present invention; and

(5) FIG. 5 is a longitudinal sectional view of a vial rubber stopper according to another embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

(6) Hereinafter, a vial rubber stopper of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to embodiments illustrated in the drawings.

(7) FIG. 1 is a longitudinal sectional view of a vial rubber stopper according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of a vial rubber stopper having multiple piercing areas according to an embodiment of the present invention. FIG. 3 is a longitudinal sectional view of a vial rubber stopper according to another embodiment of the present invention. FIG. 4 is a longitudinal sectional view of a vial rubber stopper according to another embodiment of the present invention. FIG. 5 is a longitudinal sectional view of a vial rubber stopper according to another embodiment of the present invention.

(8) The vial rubber stopper 1 of the present invention will be described with FIG. 1 as an example. A cap portion 3 having a flange 31 includes a recess at the center of a top surface, and multiple projections 32 are formed radiating from the recess in a predetermined direction at equal intervals. A piercing area 2 is disposed at the center of the cap portion 3, traversing longitudinally from the recess to a bottom surface. Two cylindrical leg portions 4 extending downward are formed on the bottom surface of the cap portion 3 to surround the piercing area 2. The piercing area 2 is formed of chlorinated butyl rubber containing no clay (rubber having low rubber hardness), and the other portion excluding the piercing area 2 is formed of rubber having high rubber hardness which is obtained by combining 60 parts of clay with 100 parts of chlorinated butyl rubber. By selecting the rubber as mentioned above, the coring will not occur even though a hollow needle pierces therethrough, and the sticking to a presser plate will not happen.

(9) In the above embodiment, chlorinated butyl rubber is used for both the rubber having high rubber hardness and the rubber having low rubber hardness. Since chlorinated butyl rubber has low gas permeability and is free from being deteriorated by medical agents and being eluted by the medical agents, it can be used preferably. The rubber hardness of the rubber stopper 1 is adjusted by formulating clay in chlorinated butyl rubber. Chlorinated butyl rubber is given as an example but not limited thereto, and any rubber may be used if the rubber is rich in airtightness which can be used as the rubber stopper 1 of a vial, and possesses no such bad influences as being deteriorated by the medical agents inside the vial and/or being eluted by the medical agents inside the vial. In addition, the rubber for the top surface of the cap portion 3 of the rubber stopper 1 is not particularly limited if the rubber has the rubber hardness preventing the sticking of the top surface to the presser plate, and the rubber for the piercing area 2 is also not particularly limited if the rubber has the rubber hardness avoiding the occurrence of the coring caused by the piercing of a hollow needle. In the above embodiment, both the top surface of the cap portion 3 and the piercing area 2 are formed of chlorinated butyl rubber; it is acceptable that the top surface of the cap portion 3 and the piercing area 2 are formed of different types of rubber.

(10) For the piercing area 2 in the above embodiment, one recess is formed at the center of the top surface of the cap portion 3, and the piercing area is formed to traverse longitudinally from the recess to the bottom surface of the cap portion 3. However, the recess may not be disposed at the center of the top surface of the cap portion 3, and the recess is not limited to one but in plural numbers. For example as illustrated in FIG. 2, it is acceptable that two recesses are provided at a predetermined interval from the center of the top surface of the cap portion 3 and the piercing area 2 is disposed to traverse longitudinally from each recess to the bottom surface of the cap portion 3. In this case, the piercing area 2 is located inside the area surrounded by the leg portion 4 of the cap portion 3. The configuration of the piercing area 2 having a recess lower than the top surface of the cap portion 3 makes it possible to prevent the piercing area 2 from contacting the presser plate and avoid the sticking of the piercing area to the presser plate.

(11) For the leg portion 4, the shape of the leg portion is not particularly limited if it can keep the vial airtight and/or liquid-tight after it is inserted into an opening of the vial. The leg portion may simply have a cylindrical shape. Preferably, in order to be used as a rubber stopper for a freeze-dried vial, it is acceptable that a portion of the cylindrical body is cut away, and it is also acceptable that a hole is disposed in the type described in the above embodiment, a C-shaped cylindrical body, or a cylinder close to the side of the cap portion 3.

(12) As another embodiment, it is acceptable that the top surface of the cap portion 3 other than the recess and the flange 31 thereof are formed of rubber having the high rubber hardness and the other portion is formed of rubber having the low rubber hardness, as illustrated in FIG. 3; it is also acceptable that the top surface of the cap portion 3 other than the recess and a side portion thereof are formed of rubber having the high rubber hardness and the other portion is formed of rubber having the low rubber hardness, as illustrated in FIG. 4; it is further acceptable that the portion of the top surface of the cap portion 3 other than the recess and the flange, which has no contact with the vial, is formed of rubber having the high rubber hardness and the other portion is formed of rubber having the low rubber hardness, as illustrated in FIG. 5. Particularly, if the rubber stopper is formed as illustrated in FIG. 4 or FIG. 5, only the rubber having the low rubber hardness contacts the vial, which makes it easier to keep the airtightness.

(13) Hereinafter, a production method will be described with the vial rubber stopper in FIG. 1 as an example. Firstly, rubber material having the high rubber hardness is introduced into a first die having a circular doughnut shape, the die is closed and the rubber is semi-vulcanized to offer a primary molding article. Thereafter, the primary molding article is transferred into a second die, rubber material having the low rubber hardness is introduced, the die is closed and the rubber is fully vulcanized to offer the vial rubber stopper. The formulation example of filling agents is listed in Table 1 (the amounts of the constituent components are expressed in parts by weight).

(14) TABLE-US-00001 TABLE 1 high hardness rubber low hardness rubber chlorinated butyl rubber 100 100 talc 30 30 clay 60 0 hydrated silica powder 15 5 titanium oxide 2 2 carbon black master-batch 0.12 0.12 zinc oxide 5 5 sulfur-containing compound 1.5 1.5

(15) With respect to the rubber stoppers obtained according to the formulations in Table 1, after a rubber stopper was capped into a vial, a boundary separation test was performed on 10 samples by pressing the piercing area with a metal rod of 6 mm from the top surface of the rubber stopper with a force of 60 N to confirm whether or not the piercing area separates from the other portion, and the boundary separation was found in none of the 10 samples.

(16) The production method is not limited to the above, and the rubber stopper may be produced according to various production methods. For example, once after the rubber having the high rubber hardness is obtained through semi-vulcanization, the portion corresponding to the piercing area is hollowed out and the hollowed portion is filled with the rubber material having the low rubber hardness; thereafter, the die is closed and the rubber is fully vulcanized to offer the vial rubber stopper.

(17) With respect to the rubber stopper obtained according to Table 1, in order to confirm whether or not the sticking to the presser plate in the capping operation and the coring in the piercing operation will occur, a top surface-plate sticking test and a coring test were performed. The result is that neither the rubber stopper stuck to the plate nor the coring occurred.

(18) <Top Surface-Plate Sticking Test>

(19) The rubber stopper was half capped into each of 25 vials with SUS#400 plate, and after being kept under a pressing pressure of 5.0 Kgf/cm.sup.2 for 15 minutes, the SUS plate was elevated. At this moment, the interval from a time when the stuck vial was elevated to a time when the vial fell and the number of tilted vials were counted.

(20) With respect to the rubber stoppers obtained according to Table 1, none stuck to the plate. Since none stuck to the plate, the number of tilted vials was zero.

(21) <Coring Test>

(22) For 10 rubber stoppers, a hollow needle (18G11/2 RB metal needle produced by Nipro) was pierced through the piercing area of each rubber stopper at a speed of 3000 mm/min for 50 times, whether or not rubber pieces and rubber notches are present was confirmed.

(23) With respect to the vial rubber stoppers obtained according to Table 1, the rubber hardness was measured by using a micro rubber hardness gauge MD-1 capa (by KOBUNSHI KEIKI CO., LTD.). The rubber hardness of the piercing area was 30 and the rubber hardness of the portions other than the piercing area was 65.

(24) In addition to the above formulations, the vial rubber stopper was made by using various types of rubber. The formulation example of filling agents is listed in Table 2 (the amounts of the constituent components are expressed in parts by weight). The vial rubber stopper was made by using the types of rubber listed in Table 2 as a rubber having the high rubber hardness and a rubber having the low rubber hardness, respectively.

(25) TABLE-US-00002 TABLE 2 formulation A formulation B formulation C formulation D formulation E formulation F formulation G chlorinated 100 100 100 100 100 100 100 butyl rubber talc 25 25 50 60 65 25 30 silica 5 10 25 UHMWPE 5 10 15 10 60 titanium 1 1 2 1 1 1 1 oxide carbon black 0.12 0.12 0.12 0.12 0.12 0.12 0.12 master-batch hydrotalcite 7 7 7 7 7 7 7 sulfur- 0.7 0.8 1 1 1 1 1 containing urea vulcanizing agent UHMWPE = Ultra high molecular weight polyethylene

(26) With respect to the rubber stoppers in the above, the top surface-plate sticking test and the coring test were performed similarly. The rubber hardness of formulations A to G and the results of the tests were listed in Table 3. The rubber hardness exhibiting the effect of preventing the sticking to the presser plate is from 58 to 90, and the rubber hardness without occurrence of the coring is from 20 to 35. Thereby, the rubber hardness from 20 to 90 holds the value capable of exhibiting the rubber functions.

(27) TABLE-US-00003 TABLE 3 formulation A formulation B formulation C formulation D formulation E formulation F formulation G rubber 30 35 40 43 47 50 58 hardness number of 15 9 2 1 3 9 0 tilted vials coring 0 0 2 19 33 34 50 occurrence number

INDUSTRIAL APPLICABILITY

(28) As mentioned above, since the vial rubber stopper of the present invention is free from sticking to the presser plate and the occurrence of the coring, it is preferably applicable to medical services.

REFERENCE SIGNS LIST

(29) 1: rubber stopper; 2: piercing area; 3: cap portion; 4: leg portion