JP2876310B2 - Rubber stopper to prevent abrasion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber molded article such as a stopper attached to a medicine bottle, for example, and more particularly, to a rubber molded article having a fluororesin film adhered to the surface of the resin film. The present invention relates to a rubber molded product that does not cause abrasion.

[0002]

2. Description of the Related Art Conventionally, a method of manufacturing a stopper has been disclosed in
No. 40491 discloses "medical laminated rubber stopper and method for producing the same".

[0003] This "method of manufacturing a laminated rubber stopper for medical use"
The purpose is to provide an inexpensive and sanitary medical laminated rubber stopper that is molded in one step, has a long leg, and is suitable for piercing a syringe needle. 0.0 as a main component
(A) with a process of improving the adhesiveness of the film-adhered surface of 02 to 0.5 mm; (B) To make a uniform composition suitable for cross-linking molding (process and), place a film, a prescribed compounding rubber, and an upper mold on the surface of a lower mold having a molding recess in the leg, Heat and pressurize the compounded rubber in the mold, press the unvulcanized rubber into both upper and lower recesses, press the film and rubber together into the lower mold recess, form a rubber stopper, (Process and step) in which the cross-linking, lamination, and bonding are integrally formed at one time. After molding the rubber, "cut one piece at a time,
Wash with water and dry to obtain a product. It is.

[0004]

However, in the conventional method for manufacturing a stopper, a vulcanized rubber is put together with a resin film into a molding cavity (cavity) of a lower mold by heating and pressing the upper and lower molds. Since the resin film is pushed in, the resin film is scratched at the edge of the cavity opening of the lower mold.

Since the surface of the resin film is stretched by the heat and pressure of the heated vulcanized rubber, when the upper and lower molds are heated and pressed, the scratches on the resin film surface are reduced by the vulcanized rubber inside the cavity. , And the release agent coated on the inner wall surface of the cavity enters into the abrasion.

Next, when the vulcanized rubber enters the cavity and is cooled by cooling after cooling, the resin film shrinks in this case, so that the release agent that has entered the abrasion is sealed on the surface of the resin film. Becomes

For this reason, there is a problem that even if the rubber stopper whose leg is covered with the resin film after the molding is cut and washed, the release agent transferred from the cavity is not easily obtained.

Further, when the resin film is stretched by being vulcanized with the vulcanized rubber each time the upper and lower molds are heated and pressed, the edge of the cavity opening of the lower mold that comes into contact with the resin film is rubbed and worn. There are easy problems. In addition, if the surface of such a mold is iron, rust is likely to occur due to repeated heating and pressurization.Therefore, the surface of the mold is plated with hard chrome for rust prevention. There is a concern that a small amount of chromium may enter into the scratches of the resin film due to repeated stretching.

[0009]

The object of the present invention is to provide a method for producing a rubber molded article according to the present invention, which has been made in view of such a problem and avoids contact between a chemical solution and rubber and allows a resin film to have a cavity release agent. It is an object of the present invention to provide a method of manufacturing a rubber molded product which does not adhere to the surface of the mold, hardly wears the edge of the cavity opening of the mold, and eliminates a concern that chromium enters the resin film.

[0010]

According to a first aspect of the present invention, there is provided a rubber molded product, wherein a molding concave portion of a lower mold is covered with a first resin film having heat resistance.
On the first resin film, a second resin film having a low frictional resistance, hardly adhering to the first resin film, and having heat resistance is placed, and unvulcanized on the second resin film. Rubber is stacked, and the upper mold and the lower mold facing the lower mold are heated and pressed to adhere the second resin film to the surface of the molded body that has entered the recess of the lower mold. After the opening of the upper mold and the lower mold, the second resin film adhered to the molded body is subjected to the heating and heating.
A rubber molded product punched by peeling off the first resin film that has been subjected to abrasion during pressurization, exposing the second resin film without abrasion due to the heating and pressurization on the surface, The first resin film and the second resin film are made of polytetrafluoroethylene, a copolymer containing tetrafluoroethylene and ethylene as a main component, a copolymer of tetrafluoroethylene and perfluoroalkylvinylether, and polyethylene naphthalate. , Polyimide,
It is characterized by being one of a simple substance and a composite of polyamide imide, polyether imide and polyethylene sulfide.

Further, the rubber molded product according to claim 2 of the present invention,
2. The rubber molded product according to claim 1, wherein the molded product is a rubber stopper, and the first resin film is heated and heated by peeling.
A second resin film without contact damage due to pressurization is exposed on the surface of the leg portion, and the second resin film is made of polytetrafluoroethylene, a copolymer containing tetrafluoroethylene and ethylene as main components, It is characterized by being composed of any one of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, polyethylene naphthalate, polyimide, polyamide imide, polyether imide, and polyethylene sulfide.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rubber molded product according to an embodiment of the present invention will be described below with reference to the drawings. Incidentally, as this rubber molded product, a rubber stopper of a medicine bottle containing a so-called freeze-dried preparation or the like is used, and this production method exhibits a remarkable effect in a rubber stopper which requires high hygiene and safety. But,
This rubber molded product is not necessarily limited to the rubber stopper of the embodiment, but can be applied to other rubber molded products covered with a resin film or the like. In addition, the resin film used in the manufacturing method is a resin film having low frictional resistance when stacked on each other and having a property of hardly adhering to each other. In this embodiment, a fluororesin film is used as an example of such a resin film. Is used.

The main feature of the rubber stopper of the present embodiment is that a plurality of fluororesin films are stacked, and the unvulcanized rubber is heated and pressurized so that the outer layer of the fluororesin film extends from the surface of the rubber stopper. To expose a fluororesin film without forming flaws.

As the rubber stopper, the leg part of the rubber stopper, that is, the part which is pressed into the inside of the mouth of the medicine bottle, and the flange part of the rubber stopper, ie, the part which comes into close contact with the upper end face of the mouth of the medicine bottle, are simultaneously integrated. Although it may be molded, from the viewpoint of improving the adhesion between the flange and the upper end surface of the mouth of the medicine bottle, a leg is made in the first step, and the unvulcanized rubber is again put on the leg in the second step. The rubber plug may be formed through two steps of performing insert molding by placing the rubber plug.

In the method for manufacturing a rubber plug of this embodiment, a mold for primary molding and a mold for secondary molding are used.

FIG. 1 shows a mold for primary molding used in the manufacturing method of this embodiment. Reference numeral 1 denotes a lower mold, and reference numeral 2 denotes an upper mold. The lower mold 1 and the upper mold 2 are arranged vertically, the upper mold 2 moves up and down with respect to the lower mold 1 to open and close the mold, and both the lower mold 1 and the upper mold 2 are heated. Is available. Although not shown, the lower mold 1 and the upper mold 2 are disposed in a casing capable of sucking air so that no air is trapped between the unvulcanized rubber or the fluororesin film or the mold. .

In this embodiment, a molding concave portion 3 for forming a leg portion of a rubber stopper of a medicine bottle for freeze-dried preparations is provided on a mold matching surface of the lower mold 1. The opening peripheral portion 3a of the molding concave portion 3 and the peripheral portion 3b of the inner protruding portion are rounded off. The outer peripheral side wall surface of the molding recess 3 is a slightly round and smooth wall surface in which the outer periphery of the rubber stopper leg bulges outward, and a draft is provided on the peripheral surface of the projection inside the molding concave portion 3. I have. Although not shown, a heater for heating the lower mold 1 is disposed below the lower mold 1.

The upper mold 2 is a plug 8 for the first step for insert molding a rubber plug in the second step (see FIG. 2).
The upper mold 2 is provided with a molding recess 4 that forms the upper surface of the plug 8 on the mold mating surface of the upper mold 2. Although not shown, the heater of the upper mold 2 is disposed above the upper mold 2. The molding recess 4 of the upper mold 2 is formed so as to round the upper part of the plug 8.

Before the lower mold 1 and the upper mold 2 are opened and the first step is started, a fluororesin film 5 as a first resin film is placed on the mating surface of the lower mold 1. A fluororesin film 6 as a second resin film is placed on the fluororesin film 5, and a butyl rubber 7 as an unvulcanized rubber is laminated on the fluororesin film 6.

As means for fixing the fluororesin film 5, as shown in FIG. 6, a fixing plate is provided on the mold-matching surface of the lower mold 1 for the primary process so that the upper surface can be at the same height as the mold-matching surface. The first fluororesin film 5 may be fixed by vertically moving the fixing plate 19.

For example, the first fluororesin film 5 is a roll having a sheet width capable of covering the entire surface of the lower mold 1, and the rolls of the first fluororesin film 5 are provided on both left and right sides or both front and rear sides of the lower mold 1. The first fluororesin film 5 is unwound from the roll, unfolded on the mold-matching surface of the lower mold 1, and the first fluorine film unfolded by moving the fixing plate 19 close to the lower mold 1. A configuration in which the resin film 5 is fixed is exemplified. In this case, the sheet-like first fluororesin film 5 may be fed or fixed between the raised fixing plate 19 and the lower mold 1.

The polymer material forming the first resin film and the second resin film is made of polytetrafluoroethylene or tetrafluoroethylene so as to have heat resistance, a low coefficient of friction, and low adhesion. Copolymer containing ethylene as a main component, copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether,
Examples include polyethylene naphthalate, polyimide, polyamide imide, polyether imide, and polyethylene sulfide. In this embodiment, a fluororesin film is used.

The unvulcanized rubber includes butyl rubber (IIR), ethylene propylene terpolymer, epichlorohydrin rubber, isoprene rubber, butadiene rubber,
A solution-polymerized styrene-butadiene rubber alone or in a composite form can be used. In this embodiment, butyl rubber is used.

FIG. 7 (a) shows a flange 8a on the leg 8a.
Shows a rubber stopper 13 integrally connected to the rubber stopper 13. The fluororesin film 6 is adhered to the surface of the leg 8a. A part of the flange 13a is surrounded and connected to the periphery of the upper end of the leg 8a, and the upper end of the fluororesin film 6 enters the inside of the flange 13a. Since the first resin film is peeled off from the surface of the fluororesin film 6 as shown in the manufacturing process described below, the surface of the fluororesin film 6 is frictionally contacted with the mold concave portion. There is no molding flaw and the surface is smooth. Since the butyl rubber is exposed on the surface of the flange portion 13a in contact with the mouth of the bottle, the sealing performance of the bottle is also improved.

FIG. 7 (b) shows the leg 8'a and the flange 1
3'a is a rubber stopper 13 'integrally formed. In this rubber plug 13 ', the surface of the leg 8'a is covered with the fluororesin film 6, but this fluororesin film 6
Since the first resin film is peeled off in the manufacturing process described below, there is no molding flaw due to friction with the molding recess,
The surface is smooth. Butyl rubber is exposed on the surface of the flange portion 13a that contacts the mouth of the bottle.

Next, a method of manufacturing the rubber stopper of the present embodiment will be described.

First, the lower mold 1 and the upper mold 2 are opened, and the first fluororesin film 5 is placed on the mold mating surface of the lower mold 1, and the first fluororesin film 5 is placed on the first fluororesin film 5. The second fluororesin film 6 is placed on the second fluororesin film 6.
An unvulcanized butyl rubber sheet 7 is placed on the sheet. With the first fluororesin film 5, the second fluororesin film 6, and the butyl rubber sheet 7 placed on the lower mold 1, the lower mold 1
The air in which the inside of the casing in which the upper mold 2 and the upper mold 2 are arranged is set to a low pressure state or a vacuum state with a low air pressure, and air stays between the lower mold 1, the fluorine resin films 5 and 6, the butyl rubber sheet 7, and the upper mold 2 Is discharged, the lower mold 1 and the upper mold 2 are heated and pressurized.

The heating temperature, pressurizing pressure and pressurizing time are set in a semi-vulcanized state in which the vulcanized rubber sheet 7 is not completely vulcanized in order to put the unvulcanized rubber sheet on the butyl rubber sheet 7 again in the secondary process and bond it. The heating temperature, pressure and pressurization time of

The unvulcanized butyl rubber sheet 7 is brought into a fluidized state by heating and pressurizing the lower mold 1 and the upper mold 2, and the fluororesin films 5, 6 are moved by the pressure applied to the flowing butyl rubber to the lower mold 1. It enters the molding recess 3.

By applying heat and pressure, the fluororesin film 5,
6 are both rubbed on the opening peripheral portion 3a of the forming concave portion 3 and the peripheral portion 3b of the projecting portion, and the opening peripheral portion 3a and the peripheral portion 3b of the projecting portion are rounded and smoothly chamfered. The fluororesin film 5 has a low frictional resistance, and has a property of elongation with heat resistance.
6 extends so as to cover the inner wall surface of the concave portion 3 for molding.

The double-layered fluororesin films 5 and 6 are difficult to adhere to each other, have very little frictional resistance and have heat resistance. Even if the resin film 5 is rubbed on the peripheral edge 3a of the opening of the concave portion 3 for molding and the peripheral edge 3b of the projection, there is no possibility that the second fluororesin film 6 will be scratched.

By heating and pressing the lower mold 1 and the upper mold 2,
As shown in FIG. 2, when the plug 8 is formed, the lower mold 1 and the upper mold 2 are opened, and the rubber sheet 9 from which many plugs 8 protrude is removed from the lower mold 1 (FIG. 3). reference). At this time, since the first fluororesin film 5 is fixed by the fixing plate 19 of the lower mold 1 as shown in FIG. 6, the first fluororesin film 5 is peeled from the rubber sheet 9. Incidentally, the reference numeral 20 in FIG.
Reference numeral 21 denotes a bearing of a shaft 22 that supports the roll 20.

Here, when the first fluororesin film 5 remaining in the lower mold 1 is returned to the inner surface of the concave portion 3 for molding,
When the next plug 8 for the first step is produced, only the second fluororesin film 6 needs to be supplied. When the first fluororesin film 5 fixed to the lower mold 1 becomes fatigued, the first fluororesin film 5 of the lower mold 1 is removed and a new one is fixed to the lower mold 1.

The rubber sheet 9 to which the second fluororesin film 6 has adhered in the first step is carried into a punching device (not shown),
The plug 8 is punched out of the rubber sheet 9. Punched plug 8
Is held in the molding recess 11 of the lower mold 10 for secondary molding, as shown in FIG.

Molding recess 11 of lower mold 10 for secondary molding
Is formed slightly shallower than the depth of the leg of the plug 8 so that a gap is formed between the upper part of the outer peripheral surface of the leg of the plug 8 and the inner surface of the recess 11 for molding. The plug body 8 is fitted so that the outer peripheral surface of the leg portion of the plug body 8 and the inner surface of the cylindrical portion fit tightly.
Are formed in substantially the same shape as the outer peripheral surface of the leg portion and the inner surface of the cylindrical portion. When the leg 8a of the plug body 8 cut out is fitted into the molding recess 11 of the lower mold 10, the upper mold 12 for secondary molding is fitted on the upper part of the plug 8 with the flange portion 13a of the rubber plug 13.
Is formed.

The inner surface of the molding recess 14 is formed into a shape in which the legs 8a of the plug 8 are fitted in a tightly contacted state, and the fluororesin film 6 adhered to the surface of the legs of the plug 8 is formed. Has a low frictional resistance, so the plug 8
Is not attached to the surface of the leg 8a of the plug 8 as in the case of stretching.

After the plug 8 is fitted into the molding recess 11 of the lower mold 10 of the secondary molding, the plug 8 is placed on the mating surface of the lower mold 10.
Two unvulcanized rubber sheets 15 and 16 are laminated. For the unvulcanized rubber sheets 15 and 16, the same type of rubber as the rubber forming the plug 8 is used, and in this embodiment, butyl rubber is used.

The unvulcanized rubber sheet 15 that is directly laminated on the mating surface of the lower mold 10 is higher than the height at which the plug 8 held by the lower mold 10 projects from the mating surface of the lower mold 10. It has a thick wall. The unvulcanized rubber sheet 15 has a circular opening 17 that exposes the plug 8 fitted to the lower mold 10. The opening 17 has a similar shape to the periphery of the plug 8, and the unvulcanized rubber sheet 1
When the rubber 5 is vulcanized, the vulcanized rubber flows into the gap 18 between the peripheral edge of the plug 8 and the peripheral edge of the opening of the molding recess 11 of the lower mold 10.

The upper unvulcanized rubber sheet 16 is
The upper surface portion 13b and the flange portion 13a of the rubber plug 13 are mainly formed during heating and pressurization by the upper mold 12, and the upper surface portion of the plug body 8 when placed on the unvulcanized rubber sheet 15. A little gap between the lower mold 10
The pressing force between the upper mold 12 and the upper mold 12 is not directly applied to the plug 8.

After the plug 8 is attached to the lower mold 10 and the unvulcanized rubber sheets 15 and 16 are positioned and mounted, the lower mold 10 and the upper mold 12 are heated and pressurized. Although not shown, heaters for the lower mold 10 and the upper mold 12 are arranged outside the respective molds.

Immediately after the start of heating and pressurizing the lower mold 10 and the upper mold 12, the pressing force is applied to the lower unvulcanized rubber sheet 15.
The rubber flows around the plug 8 without the plug 8 being crushed. When the gap 18 around the plug 8 is filled with the flowing rubber due to the heating and pressurization of the lower die 10 and the upper die 12, a pressing force is applied to the upper surface of the plug 8, and the plug 8 is pressed.
The top surface 13b of the rubber plug 13 is formed on the upper surface of the rubber plug 13. At this time, since the plug 8 is in a semi-vulcanized state, the plug 8 can be completely vulcanized by appropriately performing heating and pressurization, thereby obtaining the plug 8.
And the flange portion 13 are completely connected.

The rubber stopper 1 is provided between the lower mold 10 and the upper mold 12.
When the shape of No. 3 is formed and the vulcanized rubber is hardened, the lower mold 10 and the upper mold 12 are opened to remove the sheet-like rubber on which a large number of rubber stoppers 13 are formed. Cut off the rubber stopper 13.

In the rubber stopper according to this embodiment, the resin film (for example, a fluororesin film such as tetrafluoroethylene) covering the legs of the rubber stopper 13 is not damaged by the above-described structure. In addition, it is possible to eliminate the possibility that a release agent, abraded chromium fine particles, and the like enter the wound.

Therefore, according to the rubber plug of the present embodiment, the safety of the completed rubber plug is remarkably improved, the yield of the rubber plug is improved, and the inspection efficiency of the rubber plug can be improved. Abrasion of plating is reduced, and the production cost of rubber stoppers can be reduced.

In the first embodiment, a ring-shaped portion having an arc-shaped or rectangular cross-section and extending in the circumferential direction of the plug 8 is provided on the upper part of the outer peripheral surface of the leg of the plug 8 in the first step. After the vulcanization of the primary step, a fluororesin film is adhered to the wall of the groove by a method such as suctioning air, and rubber is filled in the groove at the time of secondary molding. A belt-like thing may be formed on the upper part of the outer peripheral surface of the leg part of the rubber stopper to improve the effect as a seal or to improve the quality in appearance.

(Modification 1) In the above embodiment, the first resin film is made of a fluororesin film, but the base of the first resin film is made of a heat-resistant material such as polyethylene terephthalate (PET) or polyamide. The base may be made of a polymer compound, and a fluororesin coating layer may be formed on the surface of the base that contacts the second resin film.

In laminating a two-layer resin film, when the first resin film is formed to be thick, when the rubber vulcanized into a sheet in the primary step is taken out from the lower mold. In addition, since the first resin film is less likely to come off from the molding recess 3 of the lower mold 1, it is more resistant to fatigue. Conversely, when the first resin film is formed to be thin, the molding accuracy is improved and flexibility against bending is generated,
Exchange is easy.

In the first embodiment, the lower mold 10 for secondary molding is formed of metal as in the prior art.
It is also conceivable to form itself with a heat-resistant polymer compound fluororesin. In this case, a concave portion for holding the plug 8 tightly is formed on the mold mating surface of the lower mold. still,
Needless to say, in this case, the lower mold 1 for primary molding is made of a fluororesin, and the fluororesin film on the side adhering to the rubber may be stretched simultaneously with heating and pressing.

Alternatively, the lower mold 10 for secondary molding may be made of a metal as in the prior art, and the concave portion 14 for molding may be coated with a fluororesin.

When the surface of the molding concave portion of the lower mold 10 for secondary molding is formed of a heat-resistant polymer compound having a low coefficient of friction such as a fluororesin, the plug 8 can be easily attached and detached and the plug can be easily removed. The possibility of scratching the leg surface of the body 8 is further reduced.

Further, the lower mold 1 for the primary molding is formed of a sintered metal or the like through which air can pass, and a concave portion for molding is formed on the mating surface of the lower mold 1. After placing the first resin film on the first mating surface, the pressurization of the vulcanized rubber and the suction of air may be performed simultaneously to adsorb the first resin film on the inner surface of the concave portion for molding.

(Second Embodiment) Further, in the first embodiment, when the molding is performed through the primary process and the secondary process, the stopper 8 and the opening edge of the molding recess 14 are formed in the secondary process. A gap was intentionally provided between the two, and the gap was filled with rubber, the upper portion of the outer peripheral surface of the leg of the completed plug 8 was covered with rubber, and the upper end of the resin film was sealed in rubber.
In the secondary process, a method was adopted in which the cut end of the resin film was exposed to the lower surface of the flange portion without providing a clearance between the upper portion of the leg of the plug 8 and the opening edge of the concave portion 14 for molding. Of course, it can be applied to the case.

(Third Embodiment) In the first embodiment,
Although the method of manufacturing the rubber stopper through the first step and the second step has been described, in order not to scratch the resin film covering the leg surface of the rubber stopper with a mold at the time of stretching, the resin film is formed. The method of laminating doubly and peeling the resin film located on the outside of the molded product from the resin film inside the molded product is to form the legs and flanges of the rubber stopper by one vulcanization, The present invention is also applicable to a method in which a resin film is attached to the surface and the lower surface of the flange portion to cover the surface.

[0054]

According to the rubber molded product according to the first aspect of the present invention, when the first resin film at the time of molding the rubber molded product is separated from the second resin film covering the rubber molded product surface, The first resin film and the second resin film are polytetrafluoroethylene, a copolymer containing tetrafluoroethylene and ethylene as main components, a copolymer of tetrafluoroethylene and perfluoroalkylvinyl ether, polyethylene naphthalate, Polyimide, polyamide imide, polyether imide, polyethylene sulfide can be any of a simple substance and a composite, so that it can be easily peeled off and heat-pressed on the surface of the second resin film on the surface of the molded rubber molded body. The surface of the rubber molded product is covered with a smooth surface without forming scratches such as scratches caused by molding. Fine particles of surface releasing agent or worn chromium resin film there is no fear of entry to.

Therefore, according to the rubber molded product of claim 1 of the present invention, the safety of the finished rubber molded product is remarkably improved, the yield of the rubber molded product is improved, and the inspection efficiency of the rubber molded product is improved. Thus, the wear of the chrome plating of the mold is reduced, and the production cost of the rubber molded product can be reduced.

Further, according to the rubber molded product of claim 2 of the present invention, the resin film covering the rubber stopper is not damaged,
It is possible to eliminate the possibility that the release agent, the worn chromium fine particles and the like enter the wound. As a result, even when the finished rubber stopper is used as a medicine stopper, its safety is remarkably improved, the yield of the rubber stopper is improved, the inspection efficiency of the rubber stopper is further improved, and the chrome plating of the mold is worn. Therefore, the production cost of the rubber stopper can be reduced and the price can be reduced.

[Brief description of the drawings]

FIG. 1 shows a first step of a rubber stopper molded through a second step, according to the method of manufacturing a rubber stopper of the first embodiment of the present invention.
Sectional drawing of the state where the fluororesin film was laid on the lower mold twice.

FIG. 2 is a cross-sectional view showing a state in which upper and lower dies of FIG. 1 are clamped, and first and second resin films and unvulcanized rubber are heated and pressed.

FIG. 3 is a cross-sectional view showing a state in which the upper and lower molds of FIG. 2 are opened and a rubber sheet having a plug formed thereon is peeled from a lower mold.

FIG. 4 is a cross-sectional view of a rubber plug formed through a secondary process in a state immediately before the secondary process.

FIG. 5 is a cross-sectional view showing a state in which a complete shape of the rubber stopper is formed in the secondary step of the rubber stopper molded through the secondary step.

FIG. 6 is a plan view showing a state in which a first fluororesin film is laid on a mating surface of a lower mold for the primary process shown in FIG. 1 and is fixed by a fixing plate.

7A is a sectional view of a rubber plug (rubber molded body) of a type in which a leg and a flange are connected, and FIG. 7B is a type in which the leg and a flange are integrally formed. Sectional view of a rubber stopper.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lower mold for primary process 2 Upper mold for primary process 3 Molding recess 4 Molding recess 5 First fluororesin film 6 Second fluororesin film 7 Unvulcanized rubber sheet 8 Plug 8a Leg Reference Signs List 9 rubber sheet 10 lower mold for secondary process 11 molding recess 12 upper mold for secondary process 13, 13 'rubber stopper 13a, 13'a flange 14 molding recess 15 unvulcanized rubber sheet 16 not yet Vulcanized rubber sheet 17 Opening 18 Clearance between the upper part of the outer peripheral surface of the leg of the plug and the opening edge of the concave part for molding 19 Fixing plate 20 Roll 21 Bearing 22 Shaft

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FIB29L 31:56 (56) References JP-A-3-136820 (JP, A) JP-A-59-5046 (JP, A) 57-47637 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 43/18-43/20 B29C 43/32-43/36 A61J 1/05 B29D 31/00

Claims (1)

(57) [Claims] 1. A heat-resistant first concave portion for molding a lower mold.
And a heat-resistant second resin film having a low frictional resistance and being less likely to adhere to the first resin film is placed on the first resin film, and the second resin film is covered with the second resin film. An unvulcanized rubber is placed on the upper mold, and the upper mold and the lower mold facing the lower mold are heated and pressed to form the second resin film into the recess of the lower mold. The second mold attached to the molded body after opening the upper mold and the lower mold whichever is attached to the surface of the body.
The first resin film having been subjected to the abrasion at the time of the heating and pressurizing was peeled off from the resin film of No. 1, and the second resinous film having no abrasion due to the heating and pressurizing was adhered to the rubber stopper leg. A rubber stopper, characterized in that: