A film-coated rubber stopper forming mold and forming method

Abstract

The present invention discloses a film-coated rubber stopper forming die and a forming method. The forming die includes an upper die core and a lower die core. The lower die core has a first cavity and a second cavity that communicate with each other from top to bottom. The first cavity is used for forming the crown part of the rubber stopper, and the second cavity is used for forming the neck part of the rubber stopper. A blocking part is arranged at the bottom edge of the first cavity to block the offset of the film during the formation of the rubber stopper neck. The forming method includes: placing the film-coated film into the first cavity of the lower die core, and making the blocking part located on the outer periphery of the film-coated film; pressing the upper die core and the lower die core together, and vulcanizing the film-coated film to form a rubber stopper. Through the blocking part in the first cavity, it is ensured that during the vulcanization and forming process of the rubber stopper, the rubber sheet that is heated and has fluidity can only flow within the area restricted by the blocking part, greatly reducing the possibility of film offset on the surface of the rubber sheet. For the rubber stopper forming method, the film-coated film is placed inside the blocking part; to prevent the occurrence of its offset under non-vertical forces.

Description

Technical Field

[0001] The present invention relates to a forming mold and a forming method, and particularly to a film-coated rubber stopper forming mold and a forming method. Background Art

[0002] A rubber stopper is an inner packaging product for medicines. Traditional rubber stoppers are made of rubber. However, under specific conditions (such as acidic or alkaline conditions), the components in the rubber stopper made of rubber will migrate into the medicine in contact with it, causing contamination and thus affecting human health. Therefore, a surface film-coated medicinal rubber stopper has emerged, which includes a bottle stopper body, and there is a layer of film on the surface of the bottle stopper body. When this film contacts the medicine, it has higher biological inertness and chemical stability than rubber, thus better ensuring the quality of the medicine.

[0003] The above-mentioned surface film-coated medicinal rubber stoppers are divided into two types. The first type is the fully film-coated rubber stopper provided in EP450098B1, which is obtained by vulcanizing and forming a film and a thin film in a forming mold with upper and lower cavities. Although the above-mentioned fully film-coated rubber stopper can have certain chemical stability, when the medicine is encapsulated, there is a film at the contact end between the crown edge of the rubber stopper and the plane edge of the medicine bottle mouth. Due to the smooth surface of the film, it will directly affect the sealing performance of the medicine. The second type of surface film-coated medicinal rubber stopper is the rubber stopper neck film-coated rubber stopper provided in patent document CN106426699A. It forms a rubber stopper neck with a film through a single vulcanization molding, and then undergoes a secondary molding. Because it requires secondary molding, the film needs to go through high temperature twice, which will cause damage to the film and make the film prone to aging. In addition, during the transportation process after the medicine is encapsulated, especially for preparations that are first filled and then sterilized, due to the shaking of the medicine, the bare rubber stopper neck part of the rubber stopper with a film will be in direct contact with medicine powder, liquid medicine, and water injection. As a result, the medicine may enter the inverted corner bare rubber stopper position at the bottle mouth through the gap between the film surface and the bottle wall, and contact the rubber without a film at the sealing surface between the crown of the rubber stopper and the bottle mouth. When the part of the rubber stopper without a film contacts the medicine, it will definitely affect the quality of the medicine.

[0004] In order to solve the problems existing in the above-mentioned film-coated rubber stoppers, patent document CN105662859A proposes a film-coated rubber stopper and a production method. The surface of the rubber stopper neck provided has a film, and the film-coated part extends from the surface of the rubber stopper neck to the plane position where the crown of the rubber stopper is sealed with the bottle mouth. Through the setting of this film-coated part, the problem that the contact end between the edge of the crown of the rubber stopper and the edge of the medicine bottle mouth has a film and affects the sealing performance is solved. At the same time, the problem that the medicine may enter the inverted corner position of the bottle mouth through the gap between the film surface and the bottle wall due to only film-coating the rubber stopper neck is also solved.

[0005] However, although the above-mentioned film-coated rubber stoppers solve the problems occurring during the use of rubber stoppers, during the process of vulcanizing and forming film-coated rubber stoppers using existing molds, the problem of film deviation occurs in the coated film, resulting in a low yield. Patent document CN112008934A proposes a film-coated rubber stopper forming mold and a forming method. The forming mold includes an upper mold core and a lower mold core; a first cavity and a second cavity that communicate with each other are arranged on the lower mold core from top to bottom; a second convex column extending towards the first cavity is arranged in the second cavity. The upper mold core includes an upper mold core body and a first convex column. During the forming process of the rubber stopper, the first convex column extends into the first cavity. Through the setting method in which the first cavity for forming the crown part of the rubber stopper and the second cavity for forming the neck part of the rubber stopper are both arranged on the lower mold core, it is ensured that during the vulcanizing and forming process of the rubber stopper, the rubber sheet with fluidity when heated can only flow within the lower mold core, and its fluidity is low, reducing the possibility of the film covering the surface of the rubber sheet shifting due to flow.

[0006] However, although this patent solves the problem of film deviation to a certain extent, in this patent, due to the closing of the mold, the upper mold core and the lower mold core approach each other, and the rubber in the film-bearing rubber sheet, positioning rubber sheet, and top rubber sheet is filled into the cavity under pressure to form the shape of the film-coated rubber stopper. During this process, affected by the flatness of the mold, the layout of the mold surface, and the evenness of heat reception of the mold, the pressure received by the bottom of the film-bearing rubber sheet from the rubber compound is not entirely vertical from top to bottom, but there will be lateral forces. Therefore, film deviation will still occur. Summary of the Invention

[0007] Object of the Invention: The object of the present invention is to provide a film-coated rubber stopper forming mold that can effectively solve the problem of film deviation of the film-coated rubber stopper;

[0008] Another object of the present invention is to provide a forming method for film-coated rubber stoppers.

[0009] Technical Solution: The rubber stopper forming mold described in the present invention includes an upper mold core and a lower mold core. The lower mold core has a first cavity and a second cavity that communicate with each other from top to bottom. The first cavity is used for forming the crown part of the rubber stopper, and the second cavity is used for forming the neck part of the rubber stopper. A blocking part for blocking the deviation of the rubber sheet for forming the neck part of the rubber stopper is arranged at the bottom edge of the first cavity.

[0010] In the above-mentioned rubber stopper forming mold, the blocking part faces the inside of the first cavity; the blocking part is located on the outer periphery of the rubber sheet for forming the neck part of the rubber stopper.

[0011] In the above-mentioned rubber stopper forming mold, the blocking part is a convex column extending towards the inside of the first cavity; the blocking part is a convex ring surrounding the outer periphery of the rubber sheet for forming the neck part of the rubber stopper.

[0012] In the above rubber stopper forming die, the blocking portions are arranged at intervals on the outer periphery of the film formed at the neck of the rubber stopper; at least two opposite blocking portions are provided on the outer periphery of the film formed at the neck of the rubber stopper.

[0013] In the above rubber stopper forming die, the cross-sectional height of the blocking portion is not greater than 2 mm, and the width is not greater than 3 mm. The film formed at the neck of the rubber stopper is a film-bearing film.

[0014] A rubber stopper forming method using the above rubber stopper forming die includes the following steps.

[0015] Place the film-bearing film into the first cavity of the lower die core, and make the blocking portion located on the outer periphery of the film-bearing film.

[0016] Press the upper die core and the lower die core together, and vulcanize the film-bearing film into a rubber stopper.

[0017] Before pressing the upper die core and the lower die core together, it further includes laying a layer of top film on the assembly, and the top film can cover the first cavity.

[0018] Beneficial effects: The technical solution of the present invention has the following advantages:

[0019] (1) Through the blocking portion in the first cavity, it is ensured that during the vulcanization molding process of the rubber stopper, the rubber sheet with fluidity when heated can only flow within the area restricted by the blocking portion, greatly reducing the possibility of the film covering on the surface of the rubber sheet shifting due to lateral force.

[0020] (2) When the blocking portion is located on the outer periphery of the film-bearing film and the blocking portion is a convex ring surrounding the film-bearing film for one week, the convex ring fixes the film-bearing film therein, so that the film-bearing film can only move downward after being extruded by the rubber material and cannot shift to the surroundings.

[0021] (3) In the rubber stopper forming method provided by the present invention, the film-bearing film is placed at the bottom of the first cavity inside the blocking portion; during the pressing together of the upper die core and the lower die core and the vulcanization molding process, the blocking portion confines the film-bearing film within a certain area, preventing its shift under the action of non-vertical force and making the film positioning more accurate. Description of the Drawings

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 It is a schematic diagram of the pressing together process of the upper die core and the lower die core provided by the embodiment Figure 1 ;

[0024] Figure 3 It is a schematic diagram of the pressing together process of the upper die core and the lower die core provided by the embodiment Figure 2 ;

[0025] Figure 4 Cross-sectional view of the film-coated rubber stopper made by the molding die provided for the embodiment;

[0026] Figure 5 Bottom view of the film-coated rubber stopper made by the molding die provided for the embodiment. Detailed implementation manners

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings of the specification.

[0028] As Figure 1 shown, this embodiment provides a rubber stopper molding die, which includes:

[0029] An upper die core 1 and a lower die core 2; the upper die core 1 includes an upper die core body and a first convex column 11; the lower die core 2 has a first cavity 22 and a second cavity 23 that communicate with each other from top to bottom; the first cavity 22 is used for forming the crown part of the rubber stopper, and the second cavity 23 is used for forming the neck part of the rubber stopper; a second convex column 21 extending towards the first cavity 22 is provided in the second cavity 23.

[0030] A blocking part 24 for blocking the offset of the film-coated film 3 is provided at the bottom edge of the first cavity 22. The blocking part 24 is a convex ring surrounding the outer periphery of the film-coated film 3 and extending into the first cavity 22. The cross-sectional height of the convex ring is 2 mm and the width is 3 mm. The specific cross-sectional height and width can be adjusted according to the size and performance index of the rubber stopper; the blocking part 24 can also be a convex column provided on the outer periphery of the film-coated film 3, and multiple convex columns can be provided, which are arranged at intervals on the outer periphery of the film-coated film 3. Among them, multiple convex columns are preferably arranged oppositely, so as to better block the outward offset of the film-coated film 3 during the pressing process of the upper die core 1 and the lower die core 2 and during the vulcanization process.

[0031] During the rubber stopper molding process, the first convex column 11 extends into the first cavity 22 and can cooperate with the second convex column 21 to clamp the rubber sheet to be vulcanized; in order to better ensure the positioning of the rubber sheet to be vulcanized, the top end of the second convex column 21 is flush with the lower surface of the first cavity 22.

[0032] In the above-mentioned rubber stopper molding die, the upper die core 1 body can be any die core body in the prior art. Preferably, it has a structure that makes the formed cavity plug crown part have annular protrusions and / or bumps, so as to prevent the rubber stopper from sticking during the conveying process.

[0033] In the above rubber stopper forming die, the first cavity 22 is a cylindrical cavity, which can form the crown of the rubber stopper after vulcanization molding; the lower die core 2 has a lower die core body, and the lower die core body is arc-shaped at the transition between the first cavity 22 and the second cavity 23, ensuring that the film covering extending to this transition will not be damaged during the molding process and subsequent use. This embodiment is an improved technical solution based on the rubber stopper forming die disclosed in the prior art CN112008934A, and the structures not described in detail in this embodiment are the same as those of this prior art.

[0034] Embodiment 2

[0035] In this embodiment, the film refers to a rubber sheet and is an unvulcanized raw rubber sheet; the film-covered rubber sheet refers to a raw rubber sheet with a film covered on one side, and the film can be any film applicable to the film-covered rubber stopper in the prior art.

[0036] This embodiment provides a method for forming a rubber stopper using the rubber stopper forming die of Embodiment 1, including the following steps:

[0037] (1) Bond the film-covered rubber sheet 3 and the positioning rubber sheet 4 to form an assembly; wherein, the film-covered rubber sheet 3 is a circular rubber sheet, and its diameter is smaller than the diameter of the first cavity 22, and its specific diameter size is determined according to the area of the film covered on the rubber stopper after molding.

[0038] (2) Place the assembly into the first cavity 22 of the lower die core 2, and make the assembly located inside the convex ring; lay a top rubber sheet 5 on the assembly, as Figure 2 shown, the top rubber sheet 5 can cover the first cavity 22.

[0039] (3) Press the upper die core 1 and the lower die core 2 together, and vulcanize the assembly and the top rubber sheet 5 to form a rubber stopper.

[0040] Among them, the diameter of the positioning rubber sheet 4 is the same as the diameter of the first cavity 22, which ensures the positioning of the film-covered rubber sheet 3 in the first cavity 22. The film-covered rubber sheet 3 can also not form an assembly with the positioning rubber sheet 4 and be placed into the first cavity, as Figure 3 shown. This is because the blocking portion in this embodiment has limited the film-covered rubber sheet 3 on its outer periphery to prevent it from shifting during the pressing of the upper die core 1 and the lower die core 2 and the vulcanization molding process. When the film-covered rubber sheet 3 and the positioning rubber sheet 4 are formed into an assembly and placed, the first convex column 11 can press the top rubber sheet 5 and the positioning rubber sheet 4 into the first cavity, and cooperate with the second convex column 21 to clamp and position each rubber sheet, thereby further realizing the accuracy of film positioning during the vulcanization process. The film-covered rubber stopper 6 prepared by this method is as Figures 4-5As shown in the figure, the film-coated rubber stopper 6 includes a rubber stopper crown portion 61, a rubber stopper neck portion 62, an annular groove 63 formed by a blocking portion of a forming die, and a plug column 64 of the rubber stopper neck portion 62. The film-coated portion extends from the surface of the rubber stopper neck to the crown portion and reaches the inner boundary of the annular groove 63. It can be seen that the film is restricted at the circular boundary of the annular groove 63 and there is no film offset. Therefore, the film coating of the rubber stopper of the present invention is accurately positioned and has high consistency.

[0041] In the above rubber stopper forming method, a top film 5 may not be laid on the assembly, and the laid top film 5 also connects the formed rubber stoppers into one piece and can finally form rubber stoppers through subsequent edge punching steps, thereby improving production efficiency.

[0042] On the lower bottom surface of the rubber stopper crown portion 61 of the film-coated rubber stopper 6 obtained by the above rubber stopper forming die, that is, at the sealing surface, there is an annular groove 63. Since the periphery of the rubber stopper is crimped with an aluminum cap during sealing, this annular groove 63 will be filled with the rubber material deformed by the extrusion of the aluminum cap around it. Therefore, it will not affect the sealing performance of the product.

Claims

1. A rubber stopper forming mold, comprising an upper mold core (1) and a lower mold core (2). The lower mold core (2) has a first cavity (22) and a second cavity (23) that communicate with each other from top to bottom. The first cavity (22) is used for forming the crown of the rubber stopper, and the second cavity (23) is used for forming the neck of the rubber stopper. Characterized in that, A blocking portion (24) for blocking the offset of the film for forming the neck of the rubber stopper is provided at the bottom edge of the first cavity (22); The blocking portion (24) faces the inside of the first cavity (22); the blocking portion (24) is located on the outer periphery of the film for forming the neck of the rubber stopper; The blocking portion (24) is a convex column extending into the first cavity (22), or the blocking portion (24) is a convex ring surrounding the outer periphery of the film for forming the neck of the rubber stopper.

2. The rubber stopper forming mold according to claim 1, Characterized in that, The blocking portions (24) are arranged at intervals on the outer periphery of the film for forming the neck of the rubber stopper.

3. The rubber stopper forming mold according to claim 1, Characterized in that, At least two opposite blocking portions (24) are provided on the outer periphery of the film for forming the neck of the rubber stopper.

4. The rubber stopper forming mold according to claim 1, Characterized in that, The cross-sectional height of the blocking portion (24) is not greater than 2 mm, and the width is not greater than 3 mm.

5. A rubber stopper forming method, using the rubber stopper forming mold according to any one of claims 1-4, Characterized in that, It includes the following steps: Put the film-coated film (3) into the first cavity (22) of the lower mold core (2), and make the blocking portion (24) located on the outer periphery of the film-coated film (3); Press the upper mold core (1) and the lower mold core (2) together, and vulcanize the film-coated film (3) into a rubber stopper.

6. The rubber stopper forming method according to claim 5, Characterized in that, Before pressing the upper mold core (1) and the lower mold core (2) together, it further includes laying a top film (5) on the film-coated film (3), and the top film (5) can cover the first cavity (22).

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