JPH09201836A - Rubber molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the safety of the resin film covering the surface of a rubber molded product. SOLUTION: The molding recessed part 3 of a lower mold 1 is covered with a first fluoroplastic film 5 having heat resistance and a second fluoroplastic film 6 is placed on the first fluoroplastic film 5 and unvulcanized rubber 7 is superposed on the second fluoroplastic film 6 and the upper mold 2 opposed to the lower mold 1 is heated and pressed to bond the second fluoroplastic film 6 to the surface of the plug member inserted into the molding recessed part 3 of the lower mold 1 and, after the upper and lower molds 1, 2 are opened, the first fluoroplastic film 5 is peeled from the second fluoroplastic film 6. The first and second fluoroplastic films 5, 6 are composed of a simple or composite of polytetrafluoroethylene, a tetrafluoroethylene/ethylene copolymer, a terafluoroethylene/perfluoroalkylvinyl ether copolymer, polyethylene naphthalate, polyimide, polyamideimide, polyetherimlde and polyethylene sulfide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber molded product such as a drug stopper attached to a medicine bottle or the like, and more specifically to a rubber molded product having a fluororesin film adhered to the surface of the resin film. The present invention relates to a rubber molded product that does not generate scratches.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Publication No.
No. 40491, “Medical laminated rubber stopper and method for producing the same” is disclosed.

This "method for producing a laminated rubber stopper for medical use" is
The purpose of the present invention is to provide “a laminated rubber stopper for medical use that is molded in one step, has a long leg length, and is suitable for piercing an injection needle, and is hygienic”. Copolymer mainly composed of 0.0
(2) To improve the adhesiveness of the film adhesive surface of 02 to 0.5 mm (with step); To make a uniform mixture suitable for cross-linking molding (with process), place a film with a predetermined treatment on the surface of the lower mold having molding recesses on the legs, a rubber with a predetermined composition, and an upper mold. Heat and pressurize the compounded rubber in the mold to press the unvulcanized rubber into both recesses of the lower mold, press the film and rubber together into the recesses of the lower mold, and mold the rubber stopper, Cross-linking, lamination, and adhesion are integrally molded at once (with process) ". After molding the rubber "cut one by one, alkali,
Wash with water and dry to make a product. Is the thing.

[0004]

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

Since the surface of this 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 vulcanized rubber will be scratched on the surface of the resin film within the cavity. The release agent coated on the inner wall surface of the cavity enters into the scratches as it spreads.

[0006] Next, when the vulcanized rubber enters the cavity and is cooled by cooling, the resin film contracts this time, so that the release agent that has entered the abrasion scratch is confined on the surface of the resin film. Becomes

For this reason, there is a problem that the mold release agent transferred from the cavity cannot be taken easily even if the rubber stopper having the leg portions covered with the resin film is cut and washed after the molding.

Further, when the resin film is placed on the vulcanized rubber and stretched each time the upper and lower molds are heated and pressed, the cavity opening edge portion of the lower mold contacting the resin film is rubbed and worn. There is an easy problem. Further, if the surface of such a mold is iron, rust easily occurs due to repeated heating and pressurization, so hard chrome for rust prevention is plated on the surface of the mold. It is feared that a small amount of chromium may enter the scratches of the resin film due to repeated stretching.

[0009]

SUMMARY OF THE INVENTION Therefore, the method for producing a rubber molded article according to the present invention has been made in view of the above problems, and avoids contact between a chemical solution and rubber, and a mold release agent for a cavity in a resin film. It is an object of the present invention to provide a method for producing a rubber molded product in which the edge of the cavity opening of the mold is not easily worn and the concern that chromium enters the resin film is eliminated.

[0010]

In order to solve the above-mentioned problems, in the rubber molded article according to claim 1 of the present invention, the molding recess of the lower mold is covered with a heat-resistant first resin film,
A second resin film, which has a small frictional resistance with respect to the first resin film, is hard to be attached to the first resin film, and has heat resistance, is placed on the first resin film, and the unvulcanized film is placed on the second resin film. Rubber is overlaid, and the upper mold and the lower mold that face 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. Then, after opening the upper mold and the lower mold, the heating / heating from the second resin film attached to the molded body is performed.
A rubber molded article obtained by peeling off the first resin film that has been scratched during pressurization, and punching out by exposing the second resin film that is not scratched by heating and pressurization to the surface, The first resin film and the second resin film are polytetrafluoroethylene, a copolymer containing tetrafluoroethylene and ethylene as a main component, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, and polyethylene naphthalate. , Polyimide,
It is characterized in that it can be any one of a polyamideimide, a polyetherimide, and a polyethylene sulfide, or a composite thereof.

The rubber molding according to claim 2 of the present invention is
The rubber molded product according to claim 1, wherein the molded product is a rubber plug, and heating is performed by peeling the first resin film.
A second resin film that is free from contact scratches due to pressure is exposed on the surface of the leg portion, and the second resin film is polytetrafluoroethylene, a copolymer containing tetrafluoroethylene and ethylene as main components, It is characterized in that it is made of any one of a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, polyethylene naphthalate, polyimide, polyamide imide, polyether imide, polyethylene sulfide, or a composite thereof.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A rubber molded product according to an embodiment of the present invention will be described below with reference to the drawings. 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 manufacturing method exerts a remarkable effect on a rubber stopper which requires high safety in hygiene. But,
This rubber molded product is not necessarily limited to the rubber plug of the embodiment, but can be applied to other rubber molded products covered with a resin film or the like. Further, as the resin film used in the manufacturing method, a resin film having a property of having less frictional resistance when stacked on each other and being less likely to adhere to each other is used. In this example, a fluororesin film is used as an example of such a resin film. Is used.

The main feature of the rubber plug which is the rubber molded product of the present embodiment is that a plurality of fluororesin films are stacked to heat and pressurize unvulcanized rubber, and the fluororesin film of the outer layer is formed from the surface of the rubber plug. This is because the fluororesin film free from molding flaws was exposed by stripping off.

As the rubber stopper, the leg portion of the rubber stopper, that is, the portion to be press-fitted into the mouth of the bottle and the flange portion of the rubber stopper, that is, the portion to be in close contact with the upper end surface of the mouth of the 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 bottle, the leg is made in the primary process and the unvulcanized rubber is re-applied on the leg in the secondary process. The rubber plug may be formed by carrying out the two steps of placing and carrying out insert molding.

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

FIG. 1 shows a die for primary molding used in the manufacturing method of the present embodiment. Reference numeral 1 is a lower die and reference numeral 2 is an upper die. The lower die 1 and the upper die 2 are arranged above and below, and the upper die 2 is moved up and down relative to the lower die 1 to open and close the die, and both the lower die 1 and the upper die 2 are heated. You can do it. Further, although not shown, the lower mold 1 and the upper mold 2 are arranged in a casing capable of sucking air so that no air may be trapped between the unvulcanized rubber, the fluororesin film or the mold. .

In this embodiment, the lower mold 1 is provided with a molding recess 3 on the mold-matching surface which forms the leg of the rubber stopper of the freeze-dried drug bottle. The opening peripheral edge portion 3a of the molding concave portion 3 and the peripheral edge portion 3b of the inner protruding portion are rounded and chamfered. The wall surface on the outer peripheral side of the molding recess 3 is a slightly round and smooth wall surface in which the outer periphery of the leg portion of the rubber plug bulges outward, and a draft is provided on the peripheral surface of the protrusion inside the molding recess 3. There is. Although not shown, a heater for heating the lower mold 1 is arranged below the lower mold 1.

The upper mold 2 is a plug body 8 for the primary process for insert molding a rubber plug in the secondary process (see FIG. 2).
The upper surface of the plug 2 is formed with a molding recess 4 which forms the upper surface of the plug 8. Although not shown, the heater of the upper mold 2 is arranged above the upper mold 2. The molding recess 4 of the upper mold 2 is formed so as to round the upper portion of the plug body 8.

Before the lower mold 1 and the upper mold 2 are opened and the primary process is started, the fluororesin film 5 as the first resin film is formed on the mold matching 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 a 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 and the like.

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 fluorine resin film 5 is unrolled from this roll and unrolled on the die matching surface of the lower die 1, and the fixing plate 19 is brought close to the lower die 1 to unroll it. A configuration for fixing the resin film 5 is exemplified. In this case, the sheet-shaped first fluororesin film 5 may be fed or fixed between the lifted fixing plate 19 and the lower mold 1.

As the polymer material for forming the first resin film and the second resin film, polytetrafluoroethylene and tetrafluoroethylene are used so as to have heat resistance, a low friction coefficient and a property of being hard to adhere. Copolymer mainly composed of ethylene, copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether,
Polyethylene naphthalate, polyimide, polyamide imide, polyether imide, polyethylene sulfide, etc. are considered. In this embodiment, a fluororesin film is used.

As the unvulcanized rubber, butyl rubber (IIR), ethylene propylene terpolymer, epichlorohydrin rubber, isoprene rubber, butadiene rubber,
Examples of the solution-polymerized styrene butadiene rubber include a simple substance and a complex thereof. In this example, butyl rubber is used.

FIG. 7A shows a leg portion 8a and a flange portion 13a.
A rubber plug 13 in which the above is integrally connected is shown. The fluororesin film 6 is attached to the surface of the leg 8a. Around the upper end of the leg 8a, a part of the flange 13a surrounds and is joined, 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 liable to be rubbed against the molding recess of the mold. It has a smooth surface with no molding scratches. Since the butyl rubber is exposed on the surface of the flange portion 13a that comes into contact with the mouth of the bottle, the sealing performance of the bottle is also improved.

FIG. 7B shows the leg portion 8'a and the flange portion 1
A rubber stopper 13 'is integrally formed with 3'a. In this rubber plug 13 ', the surface of the leg portion 8'a is covered with the fluororesin film 6.
Since the first resin film is peeled off in the manufacturing process described below, there is no molding scratch due to friction with the molding recess,
It has a smooth surface. Butyl rubber is exposed on the surface of the flange portion 13a that comes into contact with the mouth of the bottle.

Next, a method for manufacturing the rubber plug of this embodiment will be described.

First, the lower die 1 and the upper die 2 are opened, the first fluororesin film 5 is placed on the die-matching surface of the lower die 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 above. 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
Air that stays between the lower mold 1, the fluororesin films 5 and 6, the butyl rubber sheet 7, and the upper mold 2 by making the inside of the casing in which the upper mold 2 and the upper mold 2 are arranged into a low-pressure state or a vacuum state with low air pressure. After discharging, the lower mold 1 and the upper mold 2 are heated and pressurized.

The heating temperature, pressure, and pressure time are such that the unvulcanized rubber sheet is placed on the butyl rubber sheet 7 again in the secondary step and bonded, so that it is not completely vulcanized. The heating temperature, pressure, and pressure time of

By heating and pressurizing the lower mold 1 and the upper mold 2, the unvulcanized butyl rubber sheet 7 becomes a fluid state, and the pressure applied to the flowing butyl rubber causes the fluororesin films 5 and 6 to move to the lower mold 1. It enters into the molding recess 3.

By heating and pressing, the fluororesin film 5,
Both 6 are rubbed against the opening peripheral edge 3a of the molding concave portion 3 and the peripheral edge 3b of the projection, but the opening peripheral edge 3a and the peripheral edge 3b of the projection are rounded and smoothly chamfered. The fluororesin film 5, which has low frictional resistance, heat resistance, and a property of extending,
6 extends so as to cover the inner wall surface of the molding recess 3.

Further, since the fluororesin films 5 and 6 which are doubly laminated are hard to adhere to each other and have very little frictional resistance and heat resistance, the first fluorine directly contacting the lower mold 1 is used. Even if the resin film 5 is rubbed by the opening peripheral edge 3a of the molding recess 3 and the peripheral edge 3b of the protrusion, there is no possibility that the second fluororesin film 6 will be scratched.

By heating and pressurizing 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 the large number of plugs 8 project is removed from the lower mold 1 (see 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. Reference numeral 20 in FIG. 6 is the first fluororesin film 5
And a reference numeral 21 is 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 molding recess 3,
Only the second fluororesin film 6 needs to be supplied when the next plug 8 for the primary process is produced. When the first fluororesin film 5 fixed to the lower mold 1 is worn out, 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 is attached in the primary step is carried into a punching device (not shown),
The stopper 8 is punched out from the rubber sheet 9. Punched stopper 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 to be slightly shallower than the depth of the leg portion of the plug body 8 so that a gap is formed between the upper portion of the outer peripheral surface of the leg portion of the plug body 8 and the inner surface of the molding concave portion 11. Is such that the outer peripheral surface of the leg portion of the stopper 8 and the inner surface of the cylindrical portion are closely fitted to each other.
The outer peripheral surface of the leg portion and the inner surface of the tubular portion are formed in substantially the same shape. The upper die 12 for secondary molding has a flange portion 13a of a rubber stopper 13 on the upper portion of the plug body 8 when the leg portion 8a of the plug body 8 cut into the molding recess 11 of the lower die 10 is fitted.
A circular molding recess 14 is formed to form the.

The inner surface of the molding recess 14 is formed in such a shape that the legs 8a of the plug 8 are fitted in a state in which they are in close contact with each other, and the fluororesin film 6 attached to the surface of the legs of the plug 8 is formed. Has less frictional resistance, so the plug 8
Even if it is mounted in the molding recess 14, the surface of the leg portion 8a of the plug body 8 is not scratched as in the case of stretching.

After the plug 8 is fitted into the molding recess 11 of the lower die 10 for secondary molding, the mating surface of the lower die 10 is
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 body 8 is used, and in this embodiment, butyl rubber is used.

The unvulcanized rubber sheet 15 directly laminated on the mold matching surface of the lower mold 10 has a height higher than the height at which the plug body 8 held by the lower mold 10 projects from the mold matching surface of the lower mold 10. It has a large wall thickness. In addition, the unvulcanized rubber sheet 15 has a circular opening 17 for exposing the plug body 8 fitted in the lower mold 10. The opening 17 has a shape similar to the peripheral portion of the plug body 8, and the unvulcanized rubber sheet 1
When 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 used for the lower mold 10.
When heating and pressurizing by the upper die 12, the top surface portion 13b and the flange portion 13a of the rubber plug 13 are mainly formed. When the rubber plug 13 is placed on the unvulcanized rubber sheet 15, the top surface portion of the plug body 8 is formed. There is a little gap between the lower mold 10 and
The pressing force between the upper die 12 and the upper die 12 is not directly applied to the plug body 8.

After the stopper 8 is attached to the lower mold 10 and the unvulcanized rubber sheets 15 and 16 are aligned and placed, the lower mold 10 and the upper mold 12 are heated and pressed. The heaters for the lower die 10 and the upper die 12 are arranged outside the respective dies, although not shown.

Immediately after the start of heating and pressurization of the lower mold 10 and the upper mold 12, the pressing force is first applied to the unvulcanized rubber sheet 15 below.
In addition, the rubber flows around the stopper body 8 without crushing the stopper body 8. When the rubber flowing in the clearance 18 around the plug 8 is filled by the heating / pressurization of the lower mold 10 and the upper mold 12, a pressing force is applied to the upper surface of the plug 8 to make the plug 8
The top surface portion 13b of the rubber plug 13 is formed on the upper surface portion of the. At this time, since the stopper 8 is in a semi-vulcanized state, the stopper 8 is completely vulcanized by appropriately performing heating and pressurization.
And the flange portion 13 are completely connected.

A rubber stopper 1 is provided between the lower mold 10 and the upper mold 12.
After the shape 3 is formed and the vulcanized rubber is solidified, the lower mold 10 and the upper mold 12 are opened to remove the sheet-shaped rubber having a large number of rubber stoppers 13, and a punching device (not shown) is used. Cut off the rubber stopper 13.

With the rubber stopper according to this embodiment, the resin film (for example, a fluororesin film such as tetrafluoroethylene) covering the leg portion of the rubber stopper 13 is not damaged by the above-described structure. In addition, it is possible to eliminate the risk that the mold release agent or worn fine particles of chromium enter the scratch.

Therefore, according to the rubber stopper of the present embodiment, the safety of the finished rubber stopper is remarkably improved, the yield of the rubber stopper is improved, and the inspection efficiency of the rubber stopper can be further improved. The wear of the plating is reduced, which in turn makes it possible to promote the low manufacturing cost of the rubber stopper.

In the first embodiment described above, in the primary step, a ring shape having an arcuate cross section or a rectangular cross section and extending in the circumferential direction of the plug body 8 is provided on the upper portion of the outer peripheral surface of the leg portion of the plug body 8. The groove is formed, and after the vulcanization in the primary step, air is sucked, and the fluororesin film is attached to the wall surface of this groove, and the rubber is filled into this groove during the secondary molding. A belt-shaped member may be formed on the upper portion of the outer peripheral surface of the leg portion of the rubber plug to improve the effect as a seal or improve the appearance quality.

(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 heat resistant material such as polyethylene terephthalate (PET) or polyamide. It 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.

Further, in laminating the two-layer type resin film, when the first resin film is formed thick, when the rubber vulcanized into a sheet shape in the primary step is taken out from the lower mold. Since the first resin film is less likely to come off from the molding recess 3 of the lower mold 1, it is durable against fatigue. On the contrary, when the first resin film is formed to be thin, the molding accuracy is improved and bending flexibility is generated.
Easy to replace.

In the first embodiment, the lower mold 10 for secondary molding is made of metal as in the conventional case.
It is also conceivable that 0 itself is formed of a fluororesin of a heat resistant polymer compound. In this case, a concave portion is formed on the mold matching surface of the lower mold so as to hold the stopper 8 closely. still,
Of course, in this case, it is possible that the lower molding die 1 for primary molding is made of a fluororesin and the fluororesin film on the side that adheres to the rubber is stretched simultaneously with heating and pressing.

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

When the surface of the molding recess of the lower molding die 10 for secondary molding is formed of a heat-resistant polymer compound having a small friction coefficient such as fluororesin, the plug 8 can be easily attached and detached. The possibility of scratching the surface of the legs of the body 8 is further reduced.

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

(Second Embodiment) Further, in the first embodiment, when molding is performed through the primary process and the secondary process, the opening edge portions of the plug body 8 and the molding recess 14 are subjected to the secondary process. A gap was intentionally provided between the above and the gap, and the gap was filled with rubber, and the upper part of the outer peripheral surface of the leg portion of the finished plug body 8 was covered with rubber, and the upper end portion of the resin film was enclosed in the rubber.
At the time of the secondary step, a method was adopted in which the cut end of the resin film is exposed to the lower surface of the flange portion without providing a gap between the upper portion of the leg of the plug 8 and the opening edge of the molding recess 14. Of course, it can be applied to cases.

(Third Embodiment) In the first embodiment,
Although the method of manufacturing the rubber stopper through the primary step and the secondary step has been described, the resin film is coated with a resin film in order to prevent the resin film covering the leg surface of the rubber stopper from being scratched with the mold during stretching. The method of stacking in a double layer and peeling off the resin film located on the outer side of the molded product from the resin film on the inner side of the molded product is to form the leg portion and the flange portion of the rubber plug by vulcanization once, It can also be applied to a method in which a resin film is attached to the surface and the lower surface of the flange portion to cover the resin film.

[0054]

According to the rubber molded article according to claim 1 of the present invention, when the first resin film for molding the rubber molded body is peeled from the second resin film covering the surface of the rubber molded body, The first resin film and the second resin film are polytetrafluoroethylene, a copolymer containing tetrafluoroethylene and ethylene as a main component, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, polyethylene naphthalate, Since it is either a simple substance or a composite of polyimide, polyamideimide, polyetherimide, and polyethylene sulfide, it can be easily peeled off and heated and pressed on the surface of the second resin film on the surface of the molded rubber molding. Since it has a smooth surface with no scratches or scratches due to molding, the surface of the rubber molded product must be covered. 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 further improved. It is possible to improve, the wear of the chrome plating of the mold is reduced, and the manufacturing unit price of the rubber molded product can be reduced.

According to the rubber molded product of claim 2 of the present invention, the resin film covering the rubber stopper is not scratched,
It is possible to eliminate the possibility that a mold release agent, worn fine particles of chromium, or the like enter the scratch. As a result, even when the finished rubber stopper is used as a chemical stopper, the safety is significantly improved, the yield of the rubber stopper is improved, and the inspection efficiency of the rubber stopper can be further improved. It is possible to reduce the manufacturing cost of the rubber plug and to reduce the manufacturing cost of the rubber plug.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a method of manufacturing a rubber stopper according to a first embodiment of the present invention in a primary step of a rubber stopper molded through a secondary step.
Sectional drawing of the state in which the fluororesin film was laid double on the lower die.

FIG. 2 is a cross-sectional view of a state in which the upper and lower molds of FIG. 1 are clamped and the first and second resin films and the 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 body is peeled from the lower mold.

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

FIG. 5 is a cross-sectional view showing a state where 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 the die-matching surface of the lower die for the primary step shown in FIG. 1 and fixed by a fixing plate.

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

[Explanation 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 9 Rubber sheet 10 Lower mold for secondary process 11 Molding recess 12 Upper mold for secondary process 13, 13 'Rubber plug 13a, 13'a Flange part 14 Molding recess 15 Unvulcanized rubber sheet 16 Not Vulcanized rubber sheet 17 Opening 18 Clearance between the upper peripheral surface of the leg of the plug and the opening edge of the recess for molding 19 Fixing plate 20 Roll 21 Bearing 22 Shaft

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B29K 21:00 B29L 31:56 (72) Inventor Yuichi Hiraizumi 4-2-22 Higashi Yotsugi, Katsushika-ku, Tokyo In stock company hard total chrome

Claims (2)

[Claims] 1. A molding die recess of a lower die is covered with a heat-resistant first resin film, and the first resin film has a low frictional resistance against the first resin film and hardly adheres to the first resin film. Moreover, a second resin film having heat resistance is placed, unvulcanized rubber is overlaid on the second resin film, and the upper mold and the lower mold facing the lower mold are heated and pressed. Then, the second resin film is attached to the surface of the molded body that has entered the recess of the lower mold, and the second resin film is attached to the molded body after the upper mold and the lower mold are opened. The first resin film, which had been scratched by the heating / pressing, was peeled from the resin film, and the second resin film, which was not scratched by the heating / pressing, was exposed on the surface and punched. A rubber molded product, comprising the first resin film and the second resin film. The resin film is polytetrafluoroethylene, a copolymer containing tetrafluoroethylene and ethylene as the main components, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, polyethylene naphthalate, polyimide, polyamide imide, polyether imide, A rubber molded article characterized by being either a simple substance or a composite of polyethylene sulfide. 2. The rubber molded article according to claim 1, wherein the molded article is a rubber plug, and the second resin film is free from contact scratches due to heating and pressurization due to peeling of the first resin film. This second resin film is exposed on the surface of the leg portion, and the second resin film is polytetrafluoroethylene, a copolymer containing tetrafluoroethylene and ethylene as a main component, or a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether. A rubber molded article characterized by comprising any one of polyethylene naphthalate, polyimide, polyamide imide, polyether imide, and polyethylene sulfide, or a composite thereof.