JP5981274B2 - Rubber stopper - Google Patents

Description

The present invention relates to a rubber stopper including a leg portion inserted into a vial mouth portion and a cap portion in contact with an upper edge surface of the vial mouth portion.

The produced rubber plug is detected by a camera inspection to detect foreign matter existing in the rubber or deformation due to a molding error, and defective products are removed. Therefore, if the surface is too smooth, halation occurs in an image taken by camera inspection, and a non-defective product may be detected as a defective product, or a defective product may be detected as a non-defective product. The rubber plug is packed in a bag of many products, conveyed by the parts feeder in an inverted posture with the top surface facing the conveyance surface, and inserted into the vial. For this reason, the rubber plugs or the rubber plugs and the feeders may come into close contact with each other, which may cause manufacturing problems. Accordingly, the rubber plug is required to have a surface roughness and hardness that are above a certain value.

For example, a method for preventing close contact between products by forming a warp pattern on the top surface is known (Patent Document 1). However, the wrinkle pattern is formed by surface processing of a die used for molding a rubber plug by a very expensive processing method such as electric discharge machining or etching, which increases the manufacturing cost. In contrast to these methods, shot blasting is an inexpensive method, but in order to prevent dripping of the mold shape such as ribs, the restriction that the particle size used for blasting must be less than the count F36 can be used. There is. In this case, the surface roughness Ra of the mold surface is 4.5 μm or less, and cannot be made very rough practically.

On the other hand, when the surface roughness Ra is 4.5 μm or less, the surface of the rubber plug made of vulcanized rubber such as IR or IIR has adhesiveness. Therefore, not only during transportation by the parts feeder but also when many rubber stoppers are packed together and stored, the rubber stoppers may adhere to each other, resulting in handling problems.

Japanese Patent Laid-Open No. 10-94581

An object of the present invention is to improve handling properties without excessively roughening the surface in a rubber plug using a vulcanized rubber having a strong adhesiveness.

The present invention is a rubber plug provided with a leg portion inserted into the vial mouth portion, and a cap portion in contact with the upper edge surface of the vial mouth portion, wherein the cap portion and the leg portion are formed of vulcanized rubber, The present invention relates to a rubber plug characterized in that the top surface portion Ra, which is the top surface of the cap portion, has a surface roughness Ra of 0.3 to 4.5 μm and has dotted projections on the top surface portion.

It is preferable that the surface roughness Ra of the top surface portion is 0.3 to 2.4 μm.

The legs are preferably laminated with a synthetic resin film or coated with a silicone lubricant.

It is preferable that the synthetic resin film is a fluororesin, nylon, or ultra high molecular polyethylene resin.

The vulcanized rubber is preferably butyl rubber or chlorinated butyl rubber.

In the rubber plug of the present invention, the cap portion and the leg portion are formed of vulcanized rubber, and the surface roughness Ra of the top surface portion, which is the upper surface of the cap portion, is 0.3 to 4.5 μm, and is scattered on the top surface portion. Due to the protrusions, the handling in manufacturing can be greatly improved. More specifically, the surface of the mold used for press molding can be processed by shot blasting while preventing halation and reducing the false detection probability in the camera inspection, and the manufacturing cost can be reduced. In addition, despite having a surface roughness Ra of 4.5 μm or less, since there are scattered protrusions on the top surface portion, the rubber plugs are prevented from sticking to each other and can be smoothly conveyed by the parts feeder.

The top view (a) and AA sectional view (b) of a rubber stopper are shown about one embodiment of the present invention. About other embodiment of this invention, the top view (a) of a rubber stopper and a BB partial sectional view (b) are shown. About other embodiment of this invention, the upper side figure (a) and CC line | wire partial sectional view (b) of a rubber stopper are shown.

The rubber stopper of the present invention is a rubber stopper provided with a leg portion to be inserted into the vial mouth portion and a cap portion in contact with the upper edge surface of the vial mouth portion, and the cap portion and the leg portion are made of vulcanized rubber. The surface roughness Ra of the top surface portion, which is the upper surface of the cap portion, is 0.3 to 4.5 μm, and has dotted projections on the top surface portion.

One embodiment of the rubber plug of the present invention is shown in a top view and a sectional view of FIG. 1, and another embodiment is shown in a top view and a partial sectional view in FIG. The rubber stopper of the present invention includes a leg portion inserted into the vial opening and a cap portion in contact with the upper edge surface of the vial opening.

The surface roughness Ra of the top surface portion, which is the upper surface of the shade portion, is 0.3 to 4.5 μm. The lower limit of the surface roughness Ra is preferably 0.5 μm, and more preferably 0.8 μm. If it is less than 0.3 μm, the false detection rate increases during camera inspection due to halation. The upper limit of the surface roughness Ra is preferably 2.4 μm, and more preferably 2.0 μm. If the thickness exceeds 4.5 μm, when the mold surface is processed, the shape of the mold is distorted by shot blasting, and the product shape such as ribs cannot be accurately reproduced. If the electric discharge machining or the etching process is performed instead, the mold manufacturing cost increases.

Here, in the portion having a surface roughness of 0.3 to 4.5 μm in the top surface portion, the entire top surface does not necessarily have a predetermined roughness, but 80% or more of the entire top surface is a predetermined surface. The roughness is preferably 90% or more, more preferably 95% or more.

In order to prevent adhesion, the projections have dot projections on the top surface. The scattered protrusions are not continuous protrusions on the top surface in the circumferential direction, but are protrusions partially protruding on the top surface. The shape of the interspersed projection is not particularly limited, and is not limited to a substantially circular shape such as a circle, an ellipse, a semicircle, a fan shape, or an egg shape, but a substantially rectangular shape of a track shape with semicircles on opposite sides of the rectangle. It may be a thing. In consideration of conveyance in the parts feeder, adhesion of the rubber plug to the wall surface during cleaning, and cases where many rubber plugs are packed together, it is preferable that these protrusions have a small contact surface. These protrusions are preferably those that support the main body in terms of points rather than supporting the main body on the entire surface of the top surface when the rubber plug is inverted. The number of protrusions is not particularly limited, but 4 to 12 is preferable. The arrangement state is not particularly limited, but is preferably arranged radially or along the circumference. The shape of the cap portion is not particularly limited, but it is preferable to have a circular needle puncture recess at the center of the top surface.

The shape of the leg part of the rubber plug of the present invention is not particularly limited, and may be cylindrical or bifurcated. FIG. 1 shows a rubber plug having a cylindrical leg, and FIGS. 2 and 3 show a rubber plug having a bifurcated leg. The legs are laminated with a synthetic resin film or coated with a silicone lubricant. By laminating or coating, it is possible to prevent the rubber plugs from sticking to each other and to smoothly transport the parts with the parts feeder in an inverted posture with the top surface of the cylindrical cap portion facing the transport surface. In addition, the lamination can be performed not only on the legs but also on the top surface of the cap, and a synthetic resin film can be used as in the case of the legs.

The thickness of the synthetic resin film used for laminating is preferably 25 to 150 μm, and more preferably 50 to 100 μm. If the thickness is less than 25 μm, many film tears tend to occur at the time of molding, and if it exceeds 150 μm, the dimensional stability and cost of the molded product tend to increase, which tends to be uneconomical. In the present invention, the arithmetic average roughness (Ra) is measured according to JIS B0601-2001.

The synthetic resin of the synthetic resin film is not particularly limited, but from the viewpoint of obtaining good chemical resistance, polytetrafluoroethylene (PTFE), tetrafluoroethylene / ethylene copolymer (ETFE), tetrafluoroethylene / perfluoroethylene At least one fluororesin selected from the group consisting of alkyl vinyl ether copolymer (PFA), polychlorotetrafluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF), nylon, ultra-high A molecular weight polyethylene resin is preferred. Further, as a sterilization method for medical containers, steam sterilization, ethylene oxide gas sterilization, and gamma ray sterilization are performed, but PTFE has low resistance to gamma rays. Therefore, ETFE, modified ETFE, and PCTFE, which have high resistance to gamma sterilization, are particularly preferable.

Here, ETFE is a copolymer of ethylene and tetrafluoroethylene in a molar ratio of 30/70 to 70/30, and there is a modified ETFE obtained by copolymerizing other components for the purpose of modification. Examples of other components include fluorine-containing olefins and hydrocarbon olefins. Specifically, propylene, α-olefin such as part point, hexafluoropropylene, vinylidene fluoride, perfluorobutylethylene, trifluorochloroethylene and other fluorinated olefins, ethylene vinyl ether, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether There are vinyl ethers such as fluorinated acrylates and the like, and 2 to 10 mol% is copolymerized to modify ETFE.

As the modified ETFE, ETFE having a functional group imparting adhesiveness can be suitably used. Examples of the functional group include a carboxyl group, an anhydrous carboxyl group, an epoxy group, a hydroxyl group, an isocyanate group, an ester group, and an amide group. Aldehyde group, amino group, cyano group, carbon-carbon double bond, sulfonic acid group, ether group and the like. Moreover, as a commercial item of modified ETFE, Asahi Glass Co., Ltd. full-on AH-2000 etc. are mentioned.

Examples of nylon include nylon 6, nylon 66, nylon 610, nylon 621, nylon 11, nylon 12, copolymer nylon, monomer casting nylon, nylon MXD, nylon 46, and the like. Nylon may contain fluorine.

Of these, fluororesins are preferred because they are inert, excellent in heat resistance, chemical resistance, and non-adhesiveness, and have lower frictional resistance than rubber.

The synthetic resin film is preferably subjected to a treatment for improving adhesiveness with rubber or the like. Examples of the treatment for improving the adhesion include chemical treatment, treatment for roughening the surface of the film, and combinations thereof. Specific examples include sodium treatment, glow discharge treatment, under atmospheric pressure or under vacuum. And plasma treatment (discharge treatment), excimer laser treatment (discharge treatment), and ion beam treatment.

The silicone lubricant for the coating is not particularly limited, and either a reactive type or a non-reactive type can be used, but the reactive type is desirable in consideration of subsequent processes such as cleaning.

The material of the rubber plug is not particularly limited. For example, natural rubber; butyl rubber such as butyl rubber and chlorinated butyl rubber; isoprene rubber; butadiene rubber; styrene-butadiene rubber; silicone rubber; epichlorohydrin rubber; Examples thereof include rubbers, ethylene propylene rubbers such as ethylene propylene diene rubbers, and rubber materials such as nitrile rubbers that can obtain elasticity by vulcanization. These elastic materials can be used alone or by blending a plurality of components. Of these, butyl rubbers such as butyl rubber and chlorinated butyl rubber are preferable in terms of chemical resistance and gas permeation resistance.

A known compounding agent in the rubber industry such as a vulcanizing agent such as sulfur and a vulcanization accelerator can be appropriately added to the rubber material.

The J1SA hardness of the rubber plug is not particularly limited, but is preferably 50 to 70 degrees and more preferably 55 to 65 degrees. If the angle is less than 50 degrees, leakage due to deformation of the gasket during sliding or the plunger rod may come off from the gasket during suction. On the other hand, when it exceeds 70 degrees, it is necessary to increase the molding pressure, the film is easily broken, and it tends to be difficult to remove the mold.

Further, the compression set is not particularly limited, but is preferably 20% or less, and more preferably 15% or less. If it exceeds 20%, the diameter of the annular rib is reduced during plugging, sterilization and storage, the compression rate becomes insufficient, and there is a tendency that liquid tightness and airtightness with the inner wall of the barrel cannot be maintained. Here, the compression set is a value when measured under conditions of 25% compression, 70 ± 1 ° C., and 22 hours.

The rubber plug of the present invention is prepared by using a sealed kneader, an open roll kneader, or the like to prepare a kneaded material kneaded with a compounding material at a predetermined compounding ratio, using a calender or a sheet molding machine, In addition, an unvulcanized rubber sheet of a constant weight and size and an inert synthetic resin film are placed on a mold and molded by a vacuum press, whereby a rubber plug molded sheet can be obtained.

The molding conditions are not particularly limited and may be set as appropriate. The molding temperature is preferably 155 to 200 ° C, more preferably 165 to 180 ° C, and the molding time is preferably 1 to 20 minutes, more preferably 3 to 15 minutes, more preferably 5 to 10 minutes.

It is preferable that the metal mold used for molding is roughened so that the surface roughness Ra of the top surface portion of the rubber plug is 0.3 to 4.5 μm. The method for the roughening treatment is not particularly limited, and examples thereof include electric discharge machining, etching machining, and shot blasting. Shot blasting is preferable from the viewpoint of machining cost. By changing the blast count used for molding, the surface roughness Ra can be roughened in the range of 0.3 to 4.5 μm.

Examples of the blasting projection method include mechanical, wet and pneumatic methods. Examples of the particles used for blasting include glass beads, gold sand, cast iron grit, steel grit, steel shot, cut wire, alumina, silica sand, slag and the like. As other blasting conditions, it is necessary to consider projection pressure, projection angle, projection amount, and the like. As an example of the relationship between blasting and mold surface roughness, when alumina F36 to F100 is used in a pneumatic projection method, the surface can be roughened with a surface roughness Ra of 0.3 to 4.5 μm.

Thereafter, unnecessary portions are cut and removed from the molded product of the gasket, and thereafter, cleaning, sterilization, drying, and appearance inspection are performed to obtain a finished product of the gasket.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

(Examples 1-3 and Comparative Examples 1-2)
The surface of the metal mold | die produced with the stainless steel material used for the press molding of a rubber stopper was processed using the blast of F36-F100. Using this mold, rubber plugs of Comparative Example 1 and Examples 1 to 3 were produced. The produced rubber stopper is a rubber stopper for vials having a cap diameter of 19 mm as shown in FIG.
A material consisting of silica-based reinforcing agent / magnesium oxide as the main additive and chlorinated butyl rubber consisting of titanium oxide / carbon black / crosslinking agent was used as the color pigment. Its physical properties were a Shore hardness of 43 degrees and a compression set of 13%. Using this rubber material, it was heat-molded at 170 ° C./10 minutes with a mold having a different surface roughness on the top surface of the rubber plug.
As the fluororesin film to be laminated, ETFE flex 100 μm manufactured by Asahi Glass Co., Ltd. was used, and only the leg portion of the rubber plug was laminated by two-stage molding. Two-stage molding is a method in which a leg plug is molded in one stage, and a cap and a flange are molded in two stages. A curable dimethylsiloxane was used as the silicone to be coated. The manufacturing process was performed in the order of camera inspection in a clean room after molding, punching, cleaning, silicone coating, sterilization drying treatment.

(Surface roughness Ra measurement)
The surface roughness Ra of the top surface of each rubber plug is a condition with a lens magnification of 20 times, a monitor magnification of 1 time, and a cutoff value of 0.25 mm using a Keyence laser microscope (VK-X200, manufactured by Keyence Corporation). The multiple line roughness was measured. The measurement results are shown in Table 1.

(Evaluation of camera inspection machine false detection)
For each rubber plug, products are identified by seven cameras, and one camera is used for the top surface inspection. Detected defects are kneaded foreign substances, adhered foreign substances, molding defects, punching defects, and dirt. The lightness value of black and white is calculated as a light quantity value, and a light quantity value greater than or equal to a certain value and less than or equal to a certain value, or a sudden change point in the light quantity value is recognized as defective. For this reason, when the product reflects the light from the light source and the image acquired by the camera becomes white, it is recognized as a white point defect.
1000 rubber stoppers were passed through the conveyor, and the total probability of those for which the non-defective product was determined to be defective and that for which the defective product was determined to be non-defective was calculated. The measurement results are shown in Table 1.

(Evaluation of fine particle test)
The particle test was evaluated by a method based on the Japanese Pharmacopoeia plastic drug container test method.
For the measurement of the number of fine particles, a light-blocking automatic fine particle measuring device manufactured by Rion Co., Ltd. was used. As extraction conditions, 140 mL of UF water was used for 20 rubber plugs. The measurement was performed 4 times, and the average value of the 2nd to 4th data was adopted.
As a result, the coarser the surface roughness, the worse the result of the fine particle test. In general, the results of the fine particle test are affected by the type and application amount of silicone. It is considered that the surface area increased and the amount of adhered silicone increased as the surface roughness of the top surface increased under the conditions of constant type, concentration, and coating amount. Here, the surface area, using a Keyence laser microscope (manufactured by Keyence Corporation, VK-X200), lens magnification 20x, measured by monitoring one-power conditions, the measurement unit is [mu] m ² Comparative Example The case of 1 was described as 1.

From the results shown in Table 1, when the surface roughness Ra of the top surface is 0.3 to 4.5 μm, erroneous detection by the camera inspection is eliminated, the productivity is excellent, and the number of fine particles is reduced. When the surface roughness Ra of the top surface portion is 0.3 to 2.4 μm, the balance between the erroneous detection of the camera and the number of fine particles is the best.

Claims (3)

A rubber stopper provided with a leg portion to be inserted into the vial mouth portion, and a cap portion in contact with the upper edge surface of the vial mouth portion,
The cap portion and the leg portion are formed in the vulcanized rubber, a surface roughness Ra of 0.3 to 2.4 [mu] m of the top surface portion which is the upper surface of the cap portion has a dotted projection on the top surface portion ,
A rubber plug , wherein the vulcanized rubber is butyl rubber or chlorinated butyl rubber. Rubber plug of claim 1, wherein the leg is characterized in that it is coated with a laminate or silicone lubricant synthetic resin film. The rubber plug according to claim 2 , wherein the synthetic resin film is a fluororesin, nylon, or ultrahigh molecular polyethylene resin.

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