JPH0529532B2 - - Google Patents

Description

[Detailed description of the invention]

[0001]

[Field of Industrial Application] The present invention relates to a method for manufacturing a sealing element with packing, and more specifically, a sealing element equipped with an annular resin packing, such as a cap for a wide-mouth bottle or a sealing element for a battery. Relating to a manufacturing method.

[0002]

BACKGROUND OF THE INVENTION In container lids and the like for sealing wide-mouth bottles, it is required that annular packing be applied only to the periphery that is to be engaged with the bottle opening. Conventionally, in order to provide this annular packing inside the metal shell of a container lid, a method has been adopted in which a resin or rubber solution, latex, or plastisol is applied by centrifugal coating, and then heated to dry or gel. However, this method requires a large number of steps and time to manufacture the packing, and the shape of the annular packing is the most desirable shape (profile) for sealing the container.
There is also the problem that it is difficult to control the

[0003] As an alternative to this centrifugal molding method,
A method of supplying a lump of molten thermoplastic resin to the inner surface of a container shell, and pressing this lump between a cooled pressing mold and the shell to form a packing shape ( (Japanese Patent Publication No. 41-5588) and a thermoplastic resin is supplied as a preform to the inner surface of a container lid shell, the container lid shell is heated to soften the thermoplastic resin, and then cooled. A method (Japanese Patent Publication No. 48-5706) is known in which the shell is pressed between a pressing mold and the shell to form a packing shape. This method certainly has the advantage that the packing can be formed into any predetermined shape that is convenient for sealing, but when applied to the production of the annular packing of the lid for a wide-mouth bottle mentioned above, it is difficult to form the packing into any desired shape that is convenient for sealing. Characteristics,
It is recognized that certain drawbacks arise, particularly in terms of sealing performance.

[0004] That is, when a container lid equipped with press-formed packing is used to seal a bottled product, at least one of the compressive force applied to the packing, the contact with the contents or the contents vapor, and the temperature applied during sterilization or sterilization are affected. Due to two factors, micro-cracks may occur in the packing, especially around the packing, which is the most important area for the sealing function, and the adhesiveness between the packing and the container lid shell may deteriorate, as well as during storage of the container lid. Even when applied to fillers, it deteriorates significantly over time. This tendency for cracking and adhesive deterioration is caused by the fact that in the press molding of annular packing for wide-mouth bottle lids, the molten resin mass applied to the center of the lid shell is completely spread and moved to the outer periphery, causing the resin to deteriorate. It is thought that this is closely related to the fact that the amount of radially outward movement and the speed of movement become large, and that the molten resin is moved while the outer surface is being cooled, so that significant molecular orientation tends to occur.

[0005] Such a problem of environmental stress cracking of packing occurs not only in the annular packing of lids for wide-mouth bottles, but also in the case of sealing elements for batteries. That is, even in battery sealing elements, the present inventor has already proposed that a resin packing is integrally provided with a sealing plate via a heat-adhesive primer by a press molding method.
In this packing as well, a gap must be provided in the center for the carbon current collector to pass through, and the packing is necessarily annular, so the same problem of stress cracking occurs. It happens.

[0006] Therefore, the object of the present invention is to provide a method for manufacturing a sealing element with packing, which eliminates the above-mentioned drawbacks. Another object of the present invention is to suppress the generation of residual strain in the annular packing to effectively prevent the aforementioned stress cracking and adhesive deterioration over time. It is an object of the present invention to provide a method for manufacturing a sealing element that has significantly improved peel resistance and sustained sealing properties after heat treatment. Yet another object of the invention is to provide a method for manufacturing a sealing element in which the amount of resin supplied to the shell can be metered simultaneously.

【0007】

[Means for Solving the Problems] According to the present invention, in a method for manufacturing a sealing element with packing, which has an annular resin packing tightly attached to a portion other than the center of a sealing component, a plurality of sealing components are provided. A plurality of combinations of resin extrusion die outlets and rotary blades are arranged at a single supply position of a turret that supports the part, and a predetermined amount of molten resin from each die outlet is cut off to form a packing of the sealing part. It is characterized by distributing and supplying a plurality of lumps to the annular part to be sealed, and pressing the plurality of lumps with a plunger having an annular mold surface to form an annular resin packing tightly attached to the sealing part. A method of manufacturing a sealing element with packing is provided.

[0008]

[Operation] The present invention will be explained based on specific examples shown in the accompanying drawings. In FIG. 1 showing an example of the sealing element of the invention,
In this sealing element, an anode-side sealing plate 1 made of a metal plate such as tin plate has a center panel 2, and a cap 3 for fitting an anode current collector is integrally provided in the center of the anode-side sealing plate 1. A flange portion 5 is provided around the stepped portion 4 via a stepped portion 4.
A heat-adhesive primer coating 6 is coated on at least the lower surface of the sealing plate 1, except for the recess 11 for fitting the anode current collector, and a thermoplastic resin packing 7 is applied through the coating 6. They are integrated and provided by adhesive. This packing 7 consists of a cylindrical lower protrusion 8 corresponding to the cap 3 of the sealing plate 1, a thin wall portion 9 around the protrusion, and a thick sealing engagement portion 10 on the outer periphery of the thin wall portion. It's on.

[0009] In this specific example, the packing 7 is made of an olefin resin, while the heat-adhesive primer coating 6 is made of a coating containing acid-modified olefin resin or polyethylene oxide, and more specifically, Epoxy resin, phenolic resin,
Ethylenically unsaturated carboxylic acids such as maleic acid, acrylic acid, methacrylic acid or their anhydrides are added to a paint base resin consisting of at least one of amino resin, vinyl resin, acrylic resin, etc. in polyethylene, polypropylene, ethylene-propylene. Acid-modified olefin resin produced by graft polymerization to olefin resin such as a copolymer or oxidized polyethylene produced by oxidizing polyethylene with oxygen at a solid content of 0.2 to 45%.
It is obtained by blending this paint by weight%,
It is applied to a metal material before molding or a sealing plate after molding, and then baked to form a coating film.

[0010] Furthermore, on the inner circumferential surface of the cylindrical protrusion 8 of the packing 7, there is a radially inward micro protrusion 12 for tightly and tightly holding an anode current collector to be inserted later. On the other hand, the thick outer periphery sealing engagement part 10 is also provided with a groove or step part 13 that engages with the open end of the zinc can.

[0011] According to the present invention, the molten thermoplastic resin is distributed and supplied as a plurality of divided lumps to the sealing part, that is, the annular portion where the packing of the sealing plate 1 is to be formed. 2 and 3 showing this manufacturing process, the sealing plate 1 is placed on the anvil 14 with the primer coating 6 of the sealing plate 1 facing upward. Although not shown, the anvil 14 is preheated to a temperature suitable for molding resin by a heating mechanism such as an electric heating mechanism. On this sealing plate 1, an olefin resin such as polyethylene or polypropylene, particularly a blend of the above-mentioned polyolefin and elastomer, is distributed and supplied in a molten state as a plurality of divided lumps 15a and 15b. As shown in FIG. 3, in this specific example, two molten resin lumps are distributed and fed circumferentially at approximately equal intervals.

[0012] According to the present invention, the plurality of divided molten resin lumps 15a, 15b are then pressed by a plunger 16 (FIG. 2) having an annular mold surface to form an annular resin that is in close contact with the sealing part. Form packing. In FIG. 2 showing this plunger 16, the plunger 16 is made up of a plurality of mold component members that are relatively movable in the vertical direction. The blocking rod 17, the thin part forming mold 18, the thick part forming mold 19, and the outer circumference regulating mold 20,
They are coaxially arranged in this order.

[0013] During press molding, first the inflow prevention rod 17 is lowered, and the above-mentioned fitting recess 1 of the sealing plate 1 is
By fitting this into the recess 11, resin is prevented from flowing into the recess 11 during molding. At the same time or after some time, the outer circumference regulating mold 20
is lowered to prevent the molten resin from flowing outward beyond the periphery regulated by the mold 20 during molding.

[0014] In this state, as shown in FIG. 4, the thin part forming mold 18 and the thick part forming mold 19 are lowered. By lowering these molds 18 and 19,
In the cavity between the mold 18 and the inflow prevention rod 17, there is an inner circumferential cylindrical protrusion 8, and between the lower surface of the mold 18 and the sealing plate 1, there is a thin wall part 9. The outer peripheral thick walled portions 10 are formed in the cavity regulated by the mold 19 and the regulating mold 20, respectively.

[0015] In the present invention, by distributing and supplying the packing-forming resin in a molten state and as a plurality of divided lumps to the annular portion where the packing is to be formed, stress cracking can be prevented and aging can be prevented. Very significant advantages are achieved in terms of preventing adhesive deterioration. That is, when a molten resin lump is pressed with a cooling mold,
Naturally, resin flows from the narrow part between the mold and the part to the wide part, but the problem is that when the resin passes through the narrow part, there is a strong cooling effect and the movement of the resin. It is easy to cause molecular orientation. When supplying a single lump of molten resin to the center of the part to form an annular packing,
Since all the resin must flow out to the outer periphery, that is, in the radially outward direction, through the narrow space, distortions due to molecular orientation etc. are likely to occur significantly. On the other hand, according to the present invention, if the molten resin is distributed and supplied as a plurality of divided lumps directly to the part where the annular packing is to be formed, the resin will move in the circumferential direction within the wide cavity for forming the packing. hand,
Since the annular packing is formed, the tendency for distortion due to molecular orientation etc. to occur in the formed packing is significantly suppressed, and the above-mentioned drawbacks are suppressed.

[0016] In addition, it has already been proposed to cut the packing resin extruded through an annular die into an annular shape, supply it to the container lid shell in an annular shape, and press-form this into a ring-shaped packing. (Japanese Unexamined Patent Publication No. 55-77523) However, in this case, if the pressure molding is performed at a resin temperature that does not cause distortion such as molecular orientation, a problem occurs in which the resin is significantly deformed when the annular resin is cut off. Additionally, the production speed is slow and manufacturing is impractical.

[0017] In contrast, by cutting off the resin extruded in the form of a strand according to the present invention at an appropriate timing, a plurality of resin lumps can be distributed and supplied onto the component quantitatively and uniformly. The significant advantages of high production rates are achieved. In FIG. 5, which more specifically shows the distributing and supplying of resin in the method of the present invention, a turret 22 having a large number of component support seats 21 around the periphery is rotatably provided at the resin supply and molding station. , along its circumferential travel path are provided in this order a component supply chute 23, a component preheating mechanism 24, a resin supply station 25, a forming station 26 and a finished sealing element discharge chute 27.

[0018] The component 1 is sequentially supplied to a large number of support seats 21 of the turret 22 by a supply chute 23,
It revolves in the direction of the arrow (counterclockwise). The component 1 is then preheated to a temperature suitable for resin molding by a heating mechanism 24 such as a high-frequency induction heating mechanism, and introduced into a resin supply station 25 . In this embodiment, the resin supply station 25 is
Two combinations of a resin extrusion die outlet 28 and a rotary blade 29 are arranged facing each other at a single supply position. The rotary blades 29a and 29b cut off the resin extruded at a constant speed in the form of a strand from each die outlet 28a and 28a at regular intervals, thereby controlling the metering of the resin to be supplied to the part 1. Can be done along with supply.

[0019] The resin lumps 15a and 15b are simultaneously supplied onto the component 1 from the die outlets 28a and 28b, respectively. Subsequently, at the forming station 26, press forming is carried out in the order described in FIGS. 2 and 4, and the sealing element whose annular packing has been formed is discharged to the outside of the turret by the discharge chute 27. In this specific example, two combinations of resin extrusion die outlet and rotary blade are arranged facing each other at a single supply position, but various arrangements can be adopted, such as arranging multiple units radially. can.

[0020] In FIG. 6, which shows an example in which the sealing element according to the present invention is actually applied to a dry battery, a zinc can 30 that also serves as a cathode active material and a container has an anode with a carbon current collector 31 inserted in the center. A mixture 32 is housed therein, and an electrolyte glue layer 33 is housed between the zinc can 30 and the anode mixture 32 . There is an electrically insulating resin tube 34 on the outside of the zinc can 30, and around it there is a metal exterior cylinder 35.

[0021] The opening of this unit cell is provided with a sealing element 36 according to the invention, and the carbon current collector 31 is in sealing engagement with the cylindrical protrusion 8 of the packing, while the opening edge of the zinc can 30 is It is sealingly engaged with the circumferential sealing engagement portion 10 of the packing. As described above, the sealing engagement portion 10 of the packing has a concave groove shape, and the opening edge of the zinc can engages with this concave groove, and sealing is effected by the cushioning properties of the packing. In the present invention,
Since distortions such as molecular orientation are prevented from remaining in the sealing engagement part 10, even when the sealing engagement part 10 expands and deforms in the radially and outwardly directions, it is possible to prevent cracks from occurring in the groove. The drawbacks of packing are effectively eliminated. The upper end edge 37 of the exterior cylinder 35 is curled inward, and is connected to the sealing plate 1 of the sealing element 36 via the electrically insulating resin tube 34 or another ring-shaped packing 38 to reduce the rigidity of the sealing plate 1. ensure a sealing engagement.

[0022] Although the invention has been described using a battery sealing element as an example, it is understood that, as already mentioned, the method can be applied to the production of lids with an annular packing, such as lids for wide-mouthed bottles. must be done.

【0023】

Preferred embodiments of the invention In the present invention, the metal material constituting the sealing component generally has a thickness of 1
Metal foils in the range from 100 microns, especially 5 to 100 microns, or metal sheets with a thickness of 100 microns or more are used. There are no particular restrictions on the type of metal material, such as foil or sheet untreated steel (black plate), surface treated steel,
Light metals such as aluminum are used. Appropriate examples of surface-treated steel include chemical treatments such as phosphoric acid treatment and chromic acid treatment, electrolytic treatments such as electrolytic chromic acid treatment and electric tin plating, and fusion plating treatments such as molten tin plating treatment in the form of foil or sheet. Examples include those applied to the surface of steel.

[0024] The surface of these metal materials may be coated with one or more layers of any protective paint or undercoat paint for thermal adhesion of packing, which is known per se. Suitable examples of protective coatings are phenol-epoxy paints, epoxy-urea paints, epoxy-melamine paints, phenol-epoxy-vinyl paints, epoxy-vinyl paints, vinyl chloride-vinyl acetate copolymer paints, vinyl chloride-vinyl acetate. - One or a combination of two or more of maleic anhydride copolymer paints, unsaturated polyester paints, saturated polyester paints, etc. If the protective coating itself does not have adhesive properties to the thermoplastic resin used for packing, the thermal adhesive coating for packing can be applied directly onto the metal material or via the above-mentioned protective coating. For example, when the packing resin used is an olefin resin, it is possible to use a known olefin resin thermal adhesive paint, such as a paint in which oxidized polyethylene or acid-modified olefin resin is dispersed in a film-forming resin. On the other hand, when the liner resin is a vinyl chloride resin, the above-mentioned vinyl resin paint or vinyl resin modified paint can be used.

[0025] These coated metal materials are the so-called crown,
It can be molded into any container lid shape, such as a pilfer-proof cap, screw-on cap, twist-off cap, lug cap, or easy-to-open cap, and used in the manufacturing method of the present invention. Of course, the sealing parts are not limited to those made of metal, and the present invention can also be applied to plastic caps manufactured by means such as injection molding and pressure molding.

[0026] The present invention is particularly useful for manufacturing wide-mouthed container lids with packing, and is applicable to container lid shells with a diameter of 38 mm or more, for which it has been difficult to apply packing using the conventional cold pressing method of molten polyethylene. However, it is of course also effective for container lids with smaller diameters.

[0027] In the present invention, as the thermoplastic resin for forming the packing, any thermoplastic resin that can be melt-molded and has cushioning properties as a packing is used. Thermoplastic resins that can be used particularly advantageously for the purposes of the present invention include olefinic resins, such as polyethylene, polypropylene,
One or a combination of two or more of ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, ionomer, etc. In addition, soft vinyl chloride resin can also be used. .

[0028] Particularly advantageous thermoplastic resins for the purpose of the present invention include low-density polyethylene, ethylene-based copolymers, etc. In terms of packing properties, low-density polyethylene, (a) ethylene-propylene copolymer, etc. and (b) thermoplastic elastomers, especially styrene-
It is desirable to use a composition in which at least one type of diene (butadiene or isoprene)-styrene block copolymer is blended, and these modifying components are preferably contained in an amount of 3 to 40% by weight based on the low density polyethylene. good.

[0029] The production method of the present invention has the remarkable advantage that thermoplastic resins with low melt flowability, which are difficult to handle in conventional production methods, can also be used as packing. For example, in the case of polyethylene packing, the melt index (MI)
Polyethylene itself, which has a small surface area, inherently has a low stress cracking tendency, but when such polyethylene is formed into packing using conventional molding methods, the plane orientation at the outer periphery of the packing becomes excessively large, resulting in stress cracking. It will start producing kings. On the other hand, according to the present invention, by spreading the resin in a molten state, it is possible to use polyethylene which inherently has a small tendency to stress cracking. This is an advantage. Generally used low density polyethylene desirably has an MI of 0.1 to 20 g/10 mm.

[0030] In this specification, cyclic is used in a broad sense. That is, the annular shape does not necessarily have to be a perfect circle, but includes shapes such as an ellipse, a polygon, and the like, where the center is empty and the periphery is elongated and closed. It will be obvious to those skilled in the art that such a sealing element having a non-circular outer periphery is actually widely used to seal containers having a non-circular cross section.

【0031】

[Effects of the Invention] According to the present invention, a sealing element with packing can be manufactured with a small number of steps and at a high production rate, and the obtained sealing element has remarkable advantages in terms of sealing reliability and sustainability. have

[Brief explanation of drawings]

FIG. 1 shows an example of a sealing element obtainable according to the invention.

FIG. 2 is a diagram showing the manufacturing process of the present invention.

FIG. 3 is a diagram showing the manufacturing process of the present invention.

FIG. 4 is a diagram showing the manufacturing process of the present invention.

FIG. 5 is a diagram specifically showing distribution and supply of resin in the present invention.

FIG. 6 shows the use of the sealing element according to the invention;

[Explanation of symbols]

1 Anode side sealing plate 2 Center panel 3 Cap 4 Step part 5 Flange part 6 Primer coating film 7 Patsuking 8 Protrusion 9 Thin wall part 10 Sealing engagement part 11 Recess 12 Microprotrusions 13 Step part 14 Anvil 15a, 15b lump 16 Plunger 17 Inflow prevention rod 18-20 Mold 21 Support seat 22 Turret 23 Supply chute 24 Preheating mechanism 25 Supply station 26 Molding station 27 Discharge chute 28a, 28b die exit 29 Rotary blade 30 Zinc can 31 Carbon current collector 32 Anode mixture 33 Electrolyte glue layer 34 Resin tube 35 Exterior cylindrical body 36 Sealing element 37 Upper edge 38 Patsuking.

Claims (1)

[Claims] Claim 1. A method for producing a sealing element with packing, which has an annular resin packing in close contact with the sealing part except for the center thereof, comprising: a single supply of a turret supporting a plurality of sealing parts; A plurality of combinations of resin extrusion die outlets and rotary blades are arranged at positions, and a predetermined amount of molten resin from each die outlet is cut off to form a plurality of lumps in an annular portion where a packing of the sealing part is to be formed. A method for manufacturing a sealing element with packing, characterized in that the plurality of lumps are pressed by a plunger having an annular mold surface to form an annular resin packing tightly attached to a sealing part.