JP2019081561A - Liner-provided cap and manufacturing method of the same - Google Patents

Abstract

To provide a liner-provided cap capable of preventing formation of an underfill part of a liner and improving sealability of a container, and a manufacturing method of the same.SOLUTION: A liner-provided cap is a cap which is mounted on a mouth part of a container and can seal the mouth part. The liner-provided cap includes: a cap body having a top plate part and a cylindrical part substantially suspended from a peripheral edge of the top plate part; and a liner provided on an inner surface of the top plate part. The liner includes: a slide layer arranged on an inner surface side of the top plate part and sliding with the top plate part; and a seal layer laminated on the slide layer, formed so that the material is softer and an outer diameter is smaller than the slide layer and coming into contact with the container. In the slide layer, a surface roughness Rz of a first surface on the lamination surface side of the seal layer is 5.0 μm or more and 50.0 μm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liner cap which seals containers for beverages and the like, and a method of manufacturing the same.

  As a cap mounted on a container made of steel, aluminum alloy or the like, there is known a cap provided with a metal cap body and a liner provided on the inner surface of a top plate portion of the cap body. Then, when the container is closed by the cap, the liner abuts on the top of the mouth of the container to seal the inside of the container.

  As a cap (a cap with a liner) provided with such a liner, conventionally, a molten resin ball is dropped to the inner surface of the top plate portion of the cap main body, and molded by a molding die. In-shell mold type metal caps forming liners are known.

  For example, in Patent Document 1, a predetermined amount of melted soft synthetic resin material is supplied into a cap (metal cap), and the synthetic resin material is pressed by a liner forming jig to be molded, and the synthetic resin liner is produced. It is described that it forms in the state which adhere | attached on the inner surface of the top-plate part of a cap. Further, according to Patent Document 1, in such a molding method, a molten synthetic resin material is offset and molded in a cap to form a non-filled portion (incompletely molded portion) in a synthetic resin liner. It is described that there is a possibility that the sealing performance of the container may be reduced due to the non-filling portion of the synthetic resin liner. In Patent Document 1, it is assumed that air is mixed between the liner forming jig and the synthetic resin liner as a cause of formation of the non-filled portion, and the surface roughness of the liner forming jig is set to a predetermined value. By setting the above and making it rough, air between the liner forming jig and the synthetic resin liner is uniformly dispersed to make the flow of the synthetic resin material uniform, and to prevent the formation of the non-filled portion. It is done. In Patent Document 1, the surface roughness Ra (according to JIS B 0601) of the synthetic resin liner is preferably 0.1 μm or more, and preferably 5.0 μm or less. The surface roughness Ry (JIS) According to B 0601) is preferably 0.1 μm or more, and preferably 50.0 μm or less.

JP 2003-200959

  However, as described in Patent Document 1, when the surface roughness of the liner forming jig is made rough, air between the liner forming jig and the synthetic resin liner can be uniformly dispersed. Also, air in the molding space can not be released to the outside smoothly, and an air pool is likely to be formed in the peripheral portion. For this reason, the flowability of the synthetic resin material is impeded in that portion, and there is a possibility that a missing portion (incompletely formed portion) is formed in the synthetic resin liner. In addition, even if the surface roughness of the liner forming jig is roughened, air between the synthetic resin liner and the top plate portion of the metal cap can not be uniformly dispersed on the opposite surface side of the synthetic resin liner, and the synthetic resin is synthesized. An air reservoir is likely to be formed between the resin liner and the metal cap. For this reason, there is a possibility that a missing portion may be formed without the resin being filled in the portion. Furthermore, when a missing portion is formed on the back surface side of the synthetic resin liner (the contact surface side of the metal cap with the top plate portion), the missing portion corresponds to the back surface side of the synthetic resin liner. It is difficult to find a missing part by inspection by hiding it.

  In addition, as described in Patent Document 1, when the surface roughness of the surface side (the contact surface side with the liner forming jig) of the synthetic resin liner is roughened, the surface area of the synthetic resin liner becomes too large. As a result, useful components (for example, flavors) in the contents (beverage) inside the container may be adsorbed to deteriorate the flavor, or the contents themselves may adhere to cause dripping.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a liner cap which can prevent the formation of a non-filling portion of the liner and improve the sealing performance of the container, and a method of manufacturing the same.

  The liner cap according to the present invention is a cap which can be attached to the mouth of a container and can seal the mouth, and has a top plate and a cylindrical portion substantially suspended from the periphery of the top plate. A sliding layer disposed on the inner surface side of the top plate and sliding on the top plate; the liner comprising: a main body; and a liner provided on the inner surface of the top plate; And a sealing layer formed in contact with the container and having a smaller outer diameter and being softer than the sliding layer, wherein the sliding layer has a surface roughness Rz of the first surface of the sealing layer on the laminated surface side. Is 5.0 μm or more and 50.0 μm or less.

  The surface roughness Rz of the first surface is more preferably 20.0 μm to 40.0 μm.

The surface roughness Rz is determined by the maximum height in accordance with JIS B 0601: 2001 in the JIS Standard (Japanese Industrial Standard).
In the liner cap configured in this manner, the sealing layer of the liner supplies the molten resin on the first surface of the sliding layer in the cap body, and the molten resin is used as a mold for forming the sealing layer (punch) The pressure is applied by molding to form (mold). The sliding layer may be formed by punching a hard sheet into a disk shape in advance, and may be disposed in the cap main body, or may be molded in the cap main body similarly to the sealing layer, that is, on the inner surface of the top plate portion. The molten resin may be supplied and pressed by a mold for forming the sliding layer to form the mold by molding.

  The mold for forming the sealing layer is, for example, a sleeve punch which contacts the first surface of the sliding layer to define the outer diameter of the sealing layer, and a sealing layer spaced from the first surface of the sliding layer. And a center punch that defines the thickness of The sealing layer supplies the molten resin onto the first surface of the sliding layer, and then presses the molten resin with a mold for forming the cooled sealing layer, and the first surface of the sliding layer and the inside of the sleeve punch It shape | molds by filling in the interior space enclosed by the surrounding surface and the pressing surface of a center punch.

  In the process of forming such a sealing layer, the molten resin supplied onto the first surface of the sliding layer has a surface roughness (maximum height) Rz of the first surface of 5.0 μm or more and 50.0 μm or less in advance. Since it is formed in the above, it is supported by the convex portion immediately after the supply without entering into the concave and convex concave portions of the first surface.

  Next, a mold for forming a sealing layer is pressed against the molten resin to bring the sleeve punch into contact with the first surface, but the surface roughness Rz of the first surface of the sliding layer is set to 5.0 μm or more and 50.0 μm or less As a result, a gap in which air can move between the inner space of the mold for forming the sealing layer and the outside is maintained between the sleeve punch and the sliding layer. For this reason, the air in the internal space is smoothly discharged from between the sleeve punch and the sliding layer, that is, from the peripheral portion of the internal space to the outside. Further, since the unevenness is formed on the first surface with the predetermined surface roughness Rz in this manner, the resistance is kept small between the convex portion of the first surface and the molten resin, and the molten resin is radially inward of the molten resin. It can be made to flow smoothly radially outward from the Therefore, the molten resin can be filled smoothly up to the peripheral portion of the inner space, and it is possible to prevent the occurrence of a flaw in the peripheral portion of the sealing layer.

  In addition, at a later stage of molding of the molten resin by the mold for sealing layer molding, the molten resin is melted toward the first surface of the sliding layer by the mold for sealing layer molding, whereby the sliding layer and the melting are melted. The air interposed between the resin and the resin is finally discharged from the peripheral portion of the inner space to the outside along the recess on the first surface. Therefore, the molten resin penetrates deeply into the unevenness of the first surface, and the molten resin is cured in this state, whereby the adhesive strength between the sliding layer and the sealing layer can be maintained high.

  As described above, in the cap with liner of the present invention, since the surface roughness Rz of the first surface of the sliding layer is 5.0 μm or more and 50.0 μm or less, a missing portion occurs at the time of molding the sealing layer. Can be prevented, and the yield of the liner can be increased. Therefore, the sealing performance of the container can be improved.

  When the surface roughness Rz of the first surface of the sliding layer is less than 5.0 μm, air can be smoothly directed outward from the peripheral portion of the internal space of the mold for forming the sealing layer when the sealing layer is formed. It becomes difficult to discharge. In addition, when the surface roughness Rz of the first surface exceeds 50.0 μm, the molten resin is likely to leak from the peripheral portion of the internal space to the outside, and there is a possibility that a missing portion may be formed in the sealing layer. The optimum range of the surface roughness Rz of the first surface is 20.0 μm or more and 40.0 μm or less.

  In a preferred embodiment of the cap with liner according to the present invention, the hardness of the sliding layer may be 70 or more and 85 or less in type D durometer hardness.

According to JIS K 7215 in JIS Standard (Japanese Industrial Standard), when Type D durometer hardness measured with Type D is 70 or more, even when a mold for forming a sealing layer is pressed against the sliding layer The uneven shape of the first surface can be maintained, and air can be smoothly discharged from between the mold and the sliding layer. Therefore, formation of the non-filling portion of the sealing layer can be reliably prevented.
If the type D durometer hardness is less than 70, when the die is pressed against the sliding layer, the unevenness of the first surface is crushed at the contact portion, which may inhibit air leakage. On the other hand, when the Type D durometer hardness exceeds 85, the hardness of the sliding layer becomes high, and the liner becomes difficult to deform. Therefore, when the liner cap is attached to the mouth of the container, the liner is less likely to be deformed along the shape of the mouth, and the adhesion between the sealing layer and the mouth may be impaired.

  In a preferred embodiment of the cap with liner according to the present invention, the thickness of the sliding layer may be 0.30 mm or more and 0.60 mm or less.

If the thickness of the sliding layer is less than 0.30 mm, when the surface roughness Rz of the first surface is increased, a portion where the thickness of the sliding layer is locally reduced may be formed, and the sliding layer may be warped. There is. Therefore, by setting the thickness of the sliding layer to 0.30 mm or more, it is possible to reliably prevent the sliding layer from being warped. Therefore, it is possible to prevent the liner from being removed from the cap body, and to maintain the sealing performance of the container with certainty.
On the other hand, when the thickness of the sliding layer exceeds 0.60 mm, the sliding layer (liner) becomes difficult to bend, and when the sliding layer is fitted into the cap main body, it is difficult to surely place it in a predetermined position Become. For this reason, there is a possibility that a defective attachment of the liner to the cap body may occur.

  In a preferred embodiment of the liner cap of the present invention, the sealing layer is made of a styrenic elastomer, and the weight of the sealing layer is 380 mg or less.

  By forming the surface roughness Rz of the first surface of the sliding layer to 5.0 μm or more and 50.0 μm or less in advance, the flowability of the molten resin can be improved at the time of molding of the sealing layer. The amount of molten resin supplied (the weight of the sealing layer) can be reduced compared to the prior art. For example, in the sealing layer made of styrenic elastomer (TPS), the peripheral amount of the sealing layer is reduced even if the weight of the sealing layer is 380 mg or less by reducing the supply amount of the molten resin required conventionally to 400 mg to 380 mg or less. It is possible to prevent the formation of a defect in the part. The preferable weight of the sealing layer is 350 mg or more.

  The method for manufacturing a liner cap according to the present invention is a cap that is attached to the mouth of a container and can seal the mouth, and includes a top plate and a cylindrical portion that is substantially suspended from the periphery of the top plate. A sliding layer sliding on the top plate, and a sealing layer formed on the sliding layer and formed softer and smaller in outer diameter than the sliding layer and in contact with the container; A method of manufacturing a linered cap having a liner provided thereon, wherein the sliding layer has a surface roughness Rz of the first surface on the side of the laminated surface on which the sealing layer is laminated 5.0 μm to 50.0 μm The molten resin is supplied onto the first surface of the sliding layer placed in the cap body, and the molten resin is pressed by a mold for forming a sealing layer to form the sealing by molding Forming a layer, and forming a liner in which the sliding layer and the sealing layer are laminated It has a liner formation process to form.

  In the liner formed by the liner forming step, the surface roughness Rz of the first surface of the sliding layer is previously formed to 5.0 μm or more and 50.0 μm or less, so the temperature decrease of the molten resin due to the unevenness of the first surface Can be maintained to reduce the resistance between the first surface and the molten resin, and when the mold for forming the sealing layer is brought into contact with the first surface at the time of forming the sealing layer, the inner space of the mold Air can be discharged smoothly from the peripheral part to the outside. Therefore, the molten resin can be smoothly and radially flowed from the inner side to the outer side in the inner space of the mold, and the molten resin can be filled up to the peripheral portion of the inner space. Therefore, it is possible to prevent the formation of a defect in the periphery of the sealing layer and to increase the yield of the liner.

  Further, as described above, since the surface roughness Rz of the first surface of the sliding layer is 5.0 μm or more and 50.0 μm or less, the molten resin has unevenness on the first surface when the sealing layer is formed. By deep penetration and curing of the molten resin in this state, high adhesive strength between the sliding layer and the sealing layer can be maintained. Therefore, the sealing layer does not come off from the sliding layer, and the sealing layer of the liner can be reliably brought into contact with the mouth when attaching the liner cap and the container, so that the sealing performance of the capped bottle can is achieved. Can be maintained reliably.

  According to the present invention, since it is possible to prevent the formation of a non-filling portion at the time of molding the sealing layer and to improve the yield of the liner, the sealing performance of the container can be improved.

It is a front view of the linered cap which made the half of the linered cap of the embodiment of the present invention the section which passes a can axis, and is a state before winding a linered cap on a container. It is explanatory drawing of each process explaining the manufacturing method of a cap with a liner. It is principal part sectional drawing which expanded a part of metal mold | die for sealing layer shaping | molding at the formation start time of the sealing layer of a liner formation process. It is principal part sectional drawing which expanded a part of metal mold | die for sealing layer formation at the time of completion | finish of shaping | molding of the sealing layer of a liner formation process. It is the front view which made the half a cross section which passes a can axis in each one for a cap with a liner shown in Drawing 1, and a bottle can with which this cap with a liner is attached. It is principal part sectional drawing which made the vicinity of the opening part of the cap can with which the cap with a liner shown in FIG.

Hereinafter, embodiments of a cap with a liner and a method of manufacturing the same according to the present invention will be described with reference to the drawings.
The liner cap of this embodiment is attached to the opening of a container such as a metal bottle can made of, for example, 38 mm diameter aluminum or aluminum alloy, and the opening is sealed.

  FIG. 1 is a front view of a liner cap 101 manufactured in the present embodiment, showing a half of the cap with a cross section (a cross section passing through the can axis), and shows a state before the container is mounted. Further, in FIG. 5, each of the liner cap 101 shown in FIG. 1 and the bottle can 201 (the container according to the present invention) to which the liner cap 101 is attached is half-sectioned (can axis Cross-sectional view). Moreover, in FIG. 5, the cap 101 with a liner and the bottle can 201 are shown in the state before mounting | wearing. On the other hand, FIG. 6 is a cross-sectional view of an essential part of the capped bottle can 301 in which the cap with liner 101 is wound and tightened on the mouth 214 of the bottle can 201.

Moreover, FIG. 2 is explanatory drawing which shows typically each process of the manufacturing method of the liner cap of embodiment of this invention. Moreover, FIG.3 and FIG.4 is explanatory drawing explaining a liner formation process among each processes of the manufacturing method of a liner cap.
In the following description, the direction shown in FIGS. 1, 5 and 6 is defined as the vertical direction.

  As shown in FIG. 1, the cap with liner 101 before container mounting has a cap body 10 formed in a cup shape, and a liner 20 provided on the inner surface of the cap body 10.

  The cap body 10 is formed, for example, by molding a plate material made of a metal such as aluminum or an aluminum alloy coated with inner and outer surfaces. Before the cap body 10 is attached to the opening 214 of the bottle can 201, as shown in FIG. 1, the disc-like top plate portion 11 and the periphery of the top plate portion 11 along the axial direction O And a substantially cylindrical cylindrical portion 12. Further, in the cylindrical portion 12, as shown in FIG. 1, the knurled recess 121 and the vent hole 122, the female screw formation scheduled portion 123, the slit 124 and the bridge are sequentially from the base end side to the tip end side on the top plate portion 11 side. 125, a foot 126 is formed.

  Among these, the knurled recess 121 formed at a position close to the top plate portion 11 in the upper portion of the cylindrical portion 12 applies a hand with a hand at the time of opening. Further, the vent holes 122 are for releasing the internal pressure at the time of opening, and a plurality of the knurled recess 121 and the vent holes 122 are formed in the circumferential direction of the cylindrical portion 12. Further, the upper piece 131 and the lower piece 132 of the vent hole 122 are formed so as to be pressed radially inward, whereby the liner 20 is disposed between the upper piece 131 and the top plate portion 11, It is being held off. The tip of the lower piece 132 is formed at a position further radially inward than the tip of the upper piece 131. Thereby, when the sliding layer 21 of the liner 20 described later is fitted into the inside of the cap body 10, the peripheral portion (peripheral portion) of the sliding layer 21 does not contact the upper piece 131, and the sliding layer 21 By sliding the inner surface of the lower piece 132 into a predetermined position.

  A plurality of slits 124 are intermittently formed circumferentially in the lower portion of the cylindrical portion 12, and a bridge 125 is formed between the adjacent slits 124, and the cylindrical portion 12 is formed via the slits 124. The upper portion 127 and the lower portion 128 are separated, and a plurality of bridges 125 formed between the slits 124 form a shape in which the upper portion 127 and the lower portion 128 are connected.

The liner 20 includes a sliding layer 21 disposed on the inner surface side of the top plate portion 11 of the cap body 10 and a sealing layer 22 stacked on the sliding layer 21. In this case, the liner 20 is rotatably installed with respect to the cap body 10.
The sliding layer 21 is formed in a disk shape (disk shape) of polypropylene or the like, and is formed slidably with the inner surface of the top plate portion 11.

Specifically, the material of the sliding layer 21 is polypropylene (PP), high density polyethylene (HDPE), polyamide (PA, commonly called nylon), polycarbonate (PC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) ), Polyacrylonitrile (PAN), polyvinyl chloride (PVC), etc. can be adopted.
In addition, it is also possible to employ | adopt multilayer sheets, such as a sheet | seat of the 3 layer structure which laminated | stacked ethylene vinyl alcohol copolymer resin (EVOH) between polypropylenes, for example as the sliding layer 21. FIG.

The sliding layer 21 has a surface roughness Rz of 5.0 μm or more and 50.0 μm or less on the first surface 251 on the lamination surface side on which the sealing layer 22 is laminated. The surface roughness Rz of the first surface 251 is more preferably 20.0 μm or more and 40.0 μm or less. The surface roughness Rz is determined by the maximum height in accordance with JIS B 0601: 2001 in the JIS Standard (Japanese Industrial Standard).
The surface roughness Rz of the second surface 252 which is the other surface of the sliding layer 21 and is the sliding surface with the top plate portion 11 is not particularly limited, but the surface of the second surface 252 The roughness Rz is preferably in the range of 5 μm or less (Rz <5 μm).

  In this case, the sliding layer 21 of the liner 20 is formed slidably with the inner surface of the top plate portion 11 of the cap body 10, and the second surface 252 of the sliding layer 21 and the inner surface of the top plate portion 11 In between, a non-volatile organic liquid such as silicone oil or glycerin is applied. In addition, while aiming at reduction of the opening torque value at the time of cap opening, a non-volatile organic liquid is apply | coated in order to improve the gas-barrier property which suppresses the approach of gas. And, in order to exert the effect, it is necessary to interpose a necessary amount of nonvolatile organic liquid between the top plate portion 11 and the sliding layer 21. For this reason, when the surface roughness Rz of the second surface 252 is too large, it is necessary to increase the application amount of the non-volatile organic liquid by the amount of the unevenness of the second surface 252. Therefore, as described above, by setting the surface roughness Rz of the second surface 252 to 5 μm or less, the coating amount of the non-volatile organic liquid can be reduced, which is economically preferable.

The hardness of the sliding layer 21 is preferably 70 or more and 85 or less in terms of type D durometer hardness. Type D durometer hardness is measured by type D in accordance with JIS K 7215 in the JIS standard.
Further, the thickness of the sliding layer 21 is formed to be substantially constant. And it is preferable that the thickness of the sliding layer 21 is 0.30 mm or more and 0.60 mm or less.

  Further, the sealing layer 22 is formed of an elastomer resin or the like that is softer than the sliding layer 21 and, as shown in FIG. 6, contacts the opening 214 (curled portion 218) of the bottle can 201 when the liner cap 101 is closed. At the same time, the inside of the bottle can 201 can be sealed.

  Specific examples of the material of the sealing layer 22 include styrene elastomer (TPS), polyolefin elastomer (TPO), urethane elastomer (TPU), polyamide elastomer (TPEA), polyester elastomer (TPEE), poly chloride A vinyl-based elastomer (PVC-TPE) or the like can be employed.

The sealing layer 22 is preferably a material that can be thermally bonded to the sliding layer 21. For example, when the sliding layer 21 is polypropylene (PP), the sealing layer 22 is a styrene elastomer (TPS) or a polyolefin elastomer (TPO) Is suitable. Further, when the sliding layer 21 is polyethylene terephthalate (PET), the sealing layer 22 is suitably a polyester-based elastomer (TPEE), and in the case of vinyl chloride (PVC) a polyvinyl chloride-based elastomer (PVC-TPE) Is suitable.
In particular, when the sliding layer 21 is formed of polypropylene (PP) which is excellent both economically and in heat resistance, the sealing layer 22 is excellent in adhesion to polypropylene and is a styrene-based elastomer (TPS) having good retort resistance performance. It is preferable to form with.

  In the present embodiment, the hardness comparison between the sliding layer 21 and the sealing layer 22 is determined by type D durometer hardness (JIS K 7217). The outer diameter of the sealing layer 22 is smaller than the outer diameter of the sliding layer 21. In FIG. 1, the sealing layer 22 is configured of an annular seal portion 23 in contact with the curled portion 218 of the mouth portion 214 and a thin portion 24 formed on the inner side, and the seal portion 23 is more than the thin portion 24. It is formed thick. Although the thickness of the sealing layer 22 is not particularly limited, for example, the thickness of the sealing portion 23 is 0.7 mm or more and 1.0 mm or less, and the thickness of the thin portion 24 is 0.2 mm or more and 0.3 mm or less .

  In addition, as shown in FIGS. 5 and 6, the cap 101 with liner configured as described above is put on the opening 214 of the bottle can 201 and the liner 20 of the inner surface of the top plate 11 of the cap main body 10 is curled. The cap with liner 101 is attached to the opening 214 of the bottle can 201 by performing capping processing in a state of being in pressure contact with the ring 218, and the cap with bottle can (container with cap) 301 is obtained. Specifically, after the contents are filled into the inside of the bottle can 201, the internal thread formation scheduled portion 123 of the cylindrical portion 12 of the cap main body 10 is screwed along the external thread portion 216 formed in the opening 214 to internal thread The liner cap 101 is attached to the opening 214 by molding 129 (see FIG. 6) and winding and locking the bottom portion 126 of the cylindrical portion 12 under the bulging portion 215. Thereby, the capped bottle can 301 in which the mouth portion 214 of the bottle can 201 is sealed by the liner cap 101 is manufactured.

  In the bottled can with cap 301 configured as described above, when the upper portion 127 above the bridge 125 of the cap with liner 101 with respect to the bottle can 201 is rotated about the can axis, the upper portion 127 is externally threaded 216 The lower portion 128 below the bridge 125 is locked to the bulging portion 215 so that the bridge 125 is broken and the upper portion 127 of the cylindrical portion 12 is moved. And the lower portion 128 are separated. Then, the upper portion (the upper portion 127 of the cylindrical portion 12) of the liner cap 101 is removed from the port portion 214, and the lower portion (the lower portion 128 of the cylindrical portion 12) of the liner cap 101 is left in the port portion 214. . Further, by removing the upper portion of the liner cap 101 from the opening 214, the opening 214 is opened, and the contents inside the bottle can 201 can be taken out. On the other hand, it is possible to reclose the opening 214 of the bottle can 201 by reattaching the upper portion of the removed liner cap 101 to the opening 214.

Next, a method of manufacturing the liner cap of the present invention will be described by taking the case of manufacturing the liner cap 101 configured as described above as an example.
As shown in the schematic view of FIG. 2, the method of manufacturing the liner cap 101 of this embodiment includes a cap body forming step of forming the cap body 10 and a liner forming step of forming the liner. .

<Cap body formation process>
As shown in FIG. 2, a metal plate 40 forming the cap body 10 is prepared. Usually, a plate member 40 having a coating applied to the inner and outer surfaces is used. In this case, the plate 40 is coated with a size coat and a top coat on the inner surface of the cap body 10. In addition, on the surface of the cap body 10, which is the outer surface side, a size coat is printed if necessary, and then a top coat (gloss) is applied.

  Then, a lubricant is applied to the plate member 40 as necessary, and punched into a cup shape by press work to form the cap main body 10 having the top plate portion 11 and the cylindrical portion 12. Further, the cap body 10 is processed along the circumferential direction of the cylindrical portion 12 in the shape of the knurled recess 121, the vent hole 122, and the like.

<Liner formation process>
The liner forming step is performed in a state where the cap body 10 is placed with the open end facing upward as shown in FIGS. 2 to 4.
First, the sliding layer 21 formed in a disk shape in advance is disposed on the inner surface of the top plate portion 11 of the cap main body 10. The outer diameter of the sliding layer 21 is set so that the peripheral portion of the sliding layer 21 is disposed radially outside the position of the tip (radially inner tip) of the upper piece 131 of the vent hole 122. It is formed larger than the inscribed circle in contact with the tip of 131. For this reason, the peripheral edge portion of the sliding layer 21 is supported by the upper side pieces 131 and does not come off the cap main body 10, and is arranged in a non-adhesive state on the inner surface of the top plate portion 11. A non-volatile organic liquid is applied to the inner surface of the top plate portion 11 of the cap body 10 before the sliding layer 21 is inserted.

  In this case, the sliding layer 21 is formed by punching a large hard sheet or a continuous hard sheet in a roll shape. The hard sheet is formed, for example, by rolling a synthetic resin plate between two rollers, and the whole is formed to a uniform thickness. At this time, when the hard sheet is rolled by forming fine irregularities by sandblasting or the like on the surface of the roller in contact with one surface of the hard sheet, the one side which becomes the first surface of the sliding layer 21 Asperities of the surface of the roller are transferred to the surface of the roller, and a surface having a desired surface roughness Rz is formed on one surface of the hard sheet. Thus, the surface roughness Rz of one surface of the hard sheet can be adjusted by adjusting the unevenness of the surface of the roller, and the surface roughness Rz of the first surface can be obtained by punching out the hard sheet thus formed. Is formed in the range of 5.0 μm to 50.0 μm.

  The sliding layer 21 can also be formed by an in-shell mold method in which molding is performed in the cap body 10. In this case, molten resin such as polypropylene is supplied to the inner surface of the top plate portion 11 of the cap body 10, and the sliding layer 21 is formed using a mold for forming the sliding layer. Further, fine irregularities are formed on the surface of the mold for forming the sliding layer by sandblasting or the like, whereby the first surface 251 of the sliding layer 21 is formed with the mold simultaneously with the formation of the sliding layer 21. The unevenness is embossed. Thereby, surface roughness Rz of the 1st surface 251 can be formed in 5.0 micrometers or more and 50.0 micrometers or less.

Next, the sealing layer 22 is formed by an in-shell mold method of molding in the cap body 10. The sliding layer 21 is inserted in advance into the cap body 10. At this time, the sliding layer 21 is disposed such that the second surface 252 is in contact with the inner surface of the top plate portion 11 of the cap body 10.
Then, as shown in FIG. 3, the molten resin R is supplied (dropped) from the extruder (not shown) to the center of the first surface 251 in a state where the sliding layer 21 is disposed in the cap body 10. Subsequently, as shown in FIG. 3 and FIG. 4, the sealing layer 22 is formed by pressing the mold M for forming the sealing layer and molding the molten resin R by molding.

  For example, as shown in FIGS. 3 and 4, the mold M for forming the sealing layer slides with the sleeve punch 410 which contacts the first surface 251 of the sliding layer 21 to define the outer diameter of the sealing layer 22. The center punch 420 is disposed at a distance from the first surface 251 of the layer 21 to define the thickness of the sealing layer 22, and the pedestal 430 on which the cap body 10 is placed. The sealing layer 22 supplies the molten resin R onto the first surface 251 of the sliding layer 21 and then presses the molten resin R with the center punch 420 and the sleeve punch 410 of the cooled mold M, Molded by filling molten resin R in an internal space (cavity space) surrounded by the first surface 251 of the dynamic layer 21, the inner peripheral surface 411 of the sleeve punch 410, and the pressing surface 421 of the tip of the center punch 420 .

  The sleeve punch 410 is formed in a cylindrical shape, and the outer peripheral surface thereof is provided smaller than the inscribed circle in contact with the tip of the upper piece 131. In addition, a center punch 420 is inserted inside the sleeve punch 410 and is provided to be movable forward and backward. Although not shown, the sleeve punch 410 is provided with biasing means (spring or the like) for pressing the sleeve punch 410 in the distal direction (downward in FIGS. 3 and 4). Then, the sleeve punch 410 presses the first surface 251 of the sliding layer 21 in the cap main body 10 by the biasing force of the biasing means, and the inner circumferential surface 411 forms the sealing layer 22. Form the perimeter.

  The center punch 420 is formed in a cylindrical shape, and the pressing surface 421 at the tip of the center punch 420 has an annular recess 423 for forming the annular seal portion 23 and a thickness smaller than that of the seal portion 23 as shown in FIG. And a cylindrical protrusion 424 for forming the thin portion 24. The cylindrical protrusion 424 is disposed radially inward of the annular recess 423.

  As shown in FIG. 3, the cap body 10 is disposed on the pedestal 430 with the outer surface of the top plate portion 11 installed, and the sliding layer 21 is in contact with the inner surface of the top plate portion 11 with the second surface 252. Be placed. In this state, a fixed amount of the molten resin R is extruded from an extruder (not shown), and the molten resin R is supplied to the center of the first surface 251 of the sliding layer 21 disposed in the cap body 10. Then, the molten resin R is immediately pressed by the sleeve punch 410 and the center punch 420 which are cooled.

  Immediately after the molten resin R is supplied onto the first surface 251 of the sliding layer 21, the surface roughness Rz of the first surface 251 is 5.0 μm to 50.0 μm, so the molten resin R is The support is supported by the convex portion without entering the fine concave and convex concave portion of the first surface 251. Therefore, the contact area between the first surface 251 of the sliding layer 21 and the molten resin R is kept small, and the temperature drop of the molten resin R is suppressed.

  Further, when the pressing of the molten resin R is started by the pressing surface 421 of the center punch 420, the surface of the cylindrical convex portion 424 first contacts the molten resin R as shown in FIG. Then, when the center punch 420 and the sleeve punch 410 move further in the direction to approach the sliding layer 21, the molten resin R pressed by the center punch 420 is radially outward as shown by the arrow A in FIG. It flows toward you and is pushed out radially. Under the present circumstances, since the unevenness | corrugation of predetermined surface roughness Rz is formed in the 1st surface 251 of the sliding layer 21, resistance is maintained small between the convex part of the 1st surface 251, and the molten resin R. The molten resin R flows smoothly from the inner side to the outer side in the radial direction.

  Further, as shown in FIG. 4, when the center punch 420 and the sleeve punch 410 move in the direction in which they approach the sliding layer 21 most, the tip (the pressing surface 412) of the sleeve punch 410 is the first surface of the sliding layer 21. As the inner space is closed, the molten resin R is further spread radially outward and reaches the annular recess 423. Also in this case, since the surface roughness Rz of the first surface 251 is 5.0 μm or more and 50.0 μm or less between the sleeve punch 410 and the sliding layer 21, the internal space of the mold M And the outside maintain a gap through which air can move. For this reason, the air in the internal space is smoothly discharged to the outside from between the sleeve punch 410 and the sliding layer 21, that is, from the peripheral portion of the internal space. Therefore, as shown in FIG. 4, the molten resin R can be smoothly filled up to the peripheral portion of the internal space (cavity space), and the molten resin R is uniformly filled in the entire area of the internal space.

  In addition, at a later stage of molding of the molten resin R by the mold M, the molten resin R is pressed toward the first surface 251 of the sliding layer 21 by the center punch 420 so that the sliding layer 21 and the molten resin R Finally, the air which has been interposed therebetween is discharged from the peripheral portion of the inner space to the outside along the recess of the first surface 251. Accordingly, the molten resin R deeply penetrates into the unevenness of the first surface 251. Then, by cooling in this state and curing the molten resin R, a circular sealing layer 22 having a small diameter and coaxial with the sliding layer 21 is formed, and a liner in which the sliding layer 21 and the sealing layer 22 are laminated 20 are formed. At the same time, a liner cap 101 including the liner 20 is manufactured.

  In the present embodiment, the sliding layer 21 and the sealing layer 22 are bonded at the time of molding by selecting the respective materials. However, in order to further enhance the adhesion between the sliding layer 21 and the sealing layer 22, corona discharge treatment, glow discharge treatment, plasma treatment, anchor coating treatment, adhesive coating, etc. are applied to the first surface 251 of the sliding layer 21. Surface treatment may be performed. The surface treatment of the first surface 251 may be performed after the sliding layer 21 is disposed in the cap body 10.

  As described above, in the cap with liner 101 of the present embodiment, the surface roughness Rz of the first surface 251 of the sliding layer 21 is previously formed to be 5.0 μm or more and 50.0 μm or less. At the time of molding 22, the temperature drop of the molten resin R can be suppressed by the unevenness of the first surface 251 to maintain the resistance between the first surface 251 and the molten resin R small, and the mold M for forming the sealing layer The air in the internal space (cavity space) of the mold M can be smoothly discharged to the outside from the peripheral portion when contacting the first surface 251. Therefore, the molten resin R can be smoothly and radially flowed from the inner side to the outer side in the inner space of the mold M, and the molten resin R can be uniformly filled to the peripheral portion of the inner space. Therefore, it is possible to prevent the formation of an underfill at the periphery of the sealing layer 22 and to improve the yield of the liner 20. In addition, the sealing portion 23 of the sealing layer 22 can be formed to have a uniform height (thickness) without variation in the circumferential direction. Therefore, by mounting the liner cap 101 thus formed on the bottle can 201, the sealing performance of the cap bottle can 301 can be improved.

  Further, in the liner cap 101, the flowability of the molten resin R at the time of molding of the sealing layer 22 by forming the surface roughness Rz of the first surface of the sliding layer to 5.0 μm or more and 50.0 μm or less in advance. It is possible to reduce the supply amount of molten resin R (the weight of the sealing layer 22) for forming the sealing layer 22 more than before. For example, in the sealing layer 22 made of styrenic elastomer (TPS), sealing is performed even if the weight of the sealing layer 22 is 380 mg or less by reducing the supply amount of the molten resin R to 400 mg or less conventionally. It is possible to prevent the formation of a defect in the periphery of the layer 22. In this case, the preferable weight of the sealing layer 22 is 350 mg or more.

  Further, as described above, since the surface roughness Rz of the first surface 251 of the sliding layer 21 is 5.0 μm or more and 50.0 μm or less, the molten resin R is the first during molding of the sealing layer 22. It deeply penetrates the unevenness of the surface 251 and the adhesion with the sliding layer 21 is enhanced. Since the molten resin R is cured in this state, the bonding area between the sliding layer 21 and the sealing layer 22 is increased, and the bonding strength between the sliding layer 21 and the sealing layer 22 can be enhanced. Therefore, the sealing layer 22 does not come off from the sliding layer 21, and the sealing layer 22 of the liner 20 is reliably brought into contact with the opening 214 of the bottle can 201 when the liner cap 101 and the bottle can 201 are attached. Thus, the sealing performance of the capped bottle can 301 can be reliably maintained.

  If the surface roughness Rz of the first surface 251 of the sliding layer 21 is less than 5.0 μm, a gap capable of moving air between the sleeve punch 410 and the sliding layer 21 is secured with a sufficient size. When forming the sealing layer 22, it becomes difficult to discharge air from the peripheral portion of the internal space (cavity space) to the outside. In addition, when the surface roughness Rz of the first surface 251 exceeds 50.0 μm, the molten resin R easily leaks from the peripheral portion of the internal space to the outside when the sealing layer 22 is formed. In this case, it becomes difficult to fill the molten resin R up to the peripheral portion at diagonal positions of the portion where the molten resin R leaks, and there is a possibility that a cutaway portion is formed in the sealing layer 22. The optimum range of the surface roughness Rz of the first surface 251 is 20.0 μm or more and 40.0 μm or less.

  From the viewpoint of improving air leakage from the peripheral portion of the internal space of the mold M for forming the sealing layer to the outside, minute unevenness is formed on the pressing surface 412 of the tip of the sleeve punch 410. A gap may be secured between the first surface 251 of the sleeve and the pressing surface 412 of the sleeve punch 410 to improve air leakage. However, when the pressing surface 412 of the sleeve punch 410 is roughly formed, when the sleeve punch 410 is inserted into the cap body 10, the pressing surface 412 contacts the inner surface of the cap body 10 and the inner surface of the cap body 10 is There is a risk of injury, which is not preferable.

  Further, in the present embodiment, since the hardness of the sliding layer 21 is 70 or more and 85 or less in type D durometer hardness, and the type D durometer hardness is 70 or more, the mold M for sealing layer molding is slid Even when the layer 21 is pressed, the unevenness can be favorably maintained without the fine unevenness of the first surface 251 being crushed. Therefore, air can be smoothly discharged from between the mold M (sleeve punch 410) and the sliding layer 21, and formation of a cutaway portion of the sealing layer 22 can be reliably prevented.

  When the type D durometer hardness of the sliding layer 21 is less than 70, when the mold M (sleeve punch 410) is pressed against the sliding layer 21, the unevenness of the first surface 251 is crushed at the contact portion. It becomes difficult to secure a sufficient gap between the sleeve punch 410 and the sliding layer 21. For this reason, there is a possibility that air escape from the peripheral part of internal space (cavity space) may be inhibited. On the other hand, when the type D durometer hardness of the sliding layer 21 exceeds 85, the hardness of the sliding layer 21 becomes high, so the liner 20 becomes difficult to deform. Therefore, when the liner cap 101 is attached to the opening 214 of the bottle can (container) 201, the liner 20 is not easily deformed along the shape of the opening 214 (curled portion 218), and the sealing layer 22 and the opening There is a possibility that adhesion with the portion 214 may be impaired.

  On the other hand, in the present embodiment, the thickness of the sliding layer 21 is 0.30 mm or more and 0.60 mm or less, and the thickness of the sliding layer 21 is 0.30 mm or more. It can be prevented reliably. Therefore, it is possible to prevent the liner 20 from being detached from the cap body 10, and the sealing performance of the capped bottle can 301 using the liner cap 101 can be reliably maintained.

  When the thickness of the sliding layer 21 is less than 0.30 mm, when the surface roughness Rz of the first surface 251 is increased, a portion where the thickness of the sliding layer 21 is locally reduced is formed, and the sliding layer is formed. There is a possibility that warpage may occur in 21. On the other hand, when the thickness of the sliding layer 21 exceeds 0.60 mm, the sliding layer 21 (liner 20) becomes difficult to bend, and when the sliding layer 21 is fitted into the cap body 10, it is surely in a predetermined position. It becomes difficult to arrange. For this reason, there is a possibility that attachment failure of liner 20 to cap body 10 may occur.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the container to which the cap with liner is attached has been described as a metal bottle can, but the container in the present invention is not limited to a metal bottle can, and a bottle Besides cans, containers such as glass bottles and PET bottles are also included.

Next, the result of producing and evaluating a cap with a liner concerning the present invention is explained.
A cap with a liner having a surface roughness Rz of the first surface of the sliding layer of 5.0 μm or more and 50.0 μm or less is manufactured as an example, and a surface roughness Rz of the first surface of the sliding layer is a conventional example. A liner cap having a surface roughness Rz of 4.5 μm, which was out of the range of 5.0 μm to 50.0 μm, was produced.

  In the cap body, paint such as epoxy phenol and polyester is applied to the inner and outer surfaces of an aluminum alloy plate with a thickness of 0.235 mm, which is punched into a cup shape by press processing, and then knurled recesses, vent holes, etc. It processed and produced. In addition, the cap main body was formed in the size for mounting | wearing with a 38 mm diameter bottle can.

  The hard sheet used as the material of the sliding layer was formed of polypropylene (PP) having a type D durometer hardness of 75 with a thickness of 0.45 mm. Further, the surface roughness Rz of one surface (surface to be the first surface) of the hard sheet was adjusted to form four types shown in Table 1. Then, these hard sheets were punched into a disk shape to form four types of sliding layers. Of the four types of sliding layers, the arithmetic average roughness Ra of the first surface in the case of the surface roughness Rz of 4.5 μm is 0.9 μm, and the first surface in the case of the surface roughness Rz of 26.0 μm Arithmetic mean roughness Ra of 1 surface was 5.2 μm.

These sliding layers are inserted into the inside of the cap body so that the second surface is in contact with the inner surface of the top plate portion of the cap body, and the first sliding layer is formed by the same in-shell mold method as the manufacturing method of the embodiment. A liner having a sealing layer laminated on the surface was formed. As an elastomer (molten resin) to be a material of the sealing layer, a styrene-based elastomer (TPS) having excellent adhesion to polypropylene (PP) and having excellent retort resistance was used.
The supply amount (elastomer weight) of the molten resin forming the sealing layer was set to 400 mg as a standard, and was varied for each type of sliding layer. Further, the supply position (drop position) of the molten resin was set at a position deviated from the center of the sliding layer (first surface), and molding was performed under the condition that chipping easily occurs in the sealing layer.

  And about the cap with these liners, the visual inspection about the presence or absence of the crack of the sealing layer was carried out. The results are shown in Table 1.

  As can be seen from the results in Table 1, samples 2 to 4 formed with the surface roughness Rz of the first surface of the sliding layer in the range of 5.0 μm to 50.0 μm are compared to sample 1 out of the range. And the incidence of chipping of the sealing layer was significantly reduced. Moreover, in samples 2 to 4, even when the elastomer weight was reduced more than sample 1, the incidence of chipping of the sealing layer could be reduced.

  From the above results, the occurrence of chipping of the sealing layer can be suppressed by setting the surface roughness Rz of the first surface of the sliding layer to 5.0 μm or more and 50.0 μm or less. In addition, the linered cap of the example (samples 2 to 4) is economically excellent because the weight of the elastomer to be supplied can be reduced as compared with the linered cap (sample 1) of the conventional example.

Reference Signs List 10 cap body 11 top plate portion 12 cylindrical portion 20 liner 21 sliding layer 22 sealing layer 23 sealing portion 24 thin portion 40 plate member 101 liner cap 121 knurled recess 122 vent hole 123 scheduled female screw formed portion 124 slit 125 bridge 126 hem portion 127 Upper part 128 Lower part 129 Female screw part 131 Upper piece 132 Lower piece 201 Bottle can (container)
214 mouth part 215 bulging part 216 male screw part 218 curled part 251 first surface 252 second surface 301 bottle can with cap (container with cap)
410 sleeve punch 411 inner circumferential surface 412 pressing surface 420 center punch 421 pressing surface 423 annular recess 424 cylindrical projection 430 pedestal M mold R for molding sealing layer molten resin

Claims (6)

A cap attached to the mouth of the container for sealing the mouth;
A cap body having a top plate portion and a cylindrical portion substantially suspended from the peripheral edge of the top plate portion;
And a liner provided on the inner surface of the top plate portion,
The liner is a sliding layer disposed on the inner surface side of the top plate and sliding on the top plate, and the liner is laminated on the sliding layer and formed softer and smaller in outer diameter than the sliding layer. A sealing layer in contact with the
The liner cap according to claim 1, wherein the surface roughness Rz of the first surface of the sealing layer on the laminated surface side in the sliding layer is 5.0 μm to 50.0 μm.   The liner cap according to claim 1, wherein the surface roughness Rz of the first surface is 20.0 μm or more and 40.0 μm or less.   The liner cap according to claim 1 or 2, wherein hardness of the sliding layer is 70 or more and 85 or less in type D durometer hardness.   The liner cap according to any one of claims 1 to 3, wherein a thickness of the sliding layer is 0.30 mm or more and 0.60 mm or less.   The liner cap according to any one of claims 1 to 4, wherein the sealing layer is made of a styrenic elastomer, and the weight of the sealing layer is 380 mg or less. A cap attached to the mouth of the container for sealing the mouth;
In a cap main body having a top plate portion and a cylindrical portion substantially suspended from the peripheral edge of the top plate portion, a sliding layer sliding on the top plate portion, and the sliding layer laminated on the sliding layer And a sealing layer which is softer, smaller in outer diameter, and is in contact with the container.
The sliding layer is formed such that the surface roughness Rz of the first surface on the lamination surface side on which the sealing layer is laminated is 5.0 μm or more and 50.0 μm or less.
A molten resin is supplied onto the first surface of the sliding layer disposed in the cap body, and the molten resin is pressed by a mold for forming a sealing layer to form the sealing layer by molding. A method of manufacturing a liner cap, comprising a liner forming step of forming a liner in which a sliding layer and the sealing layer are laminated.

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