JP2007161331A - Cap material, and container with cap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cap material, and a container with a cap capable of preventing dispersion in hardness of a liner even when the liner has a sliding layer and a sealing layer, reliably fitting the cap material with the liner fitted thereto to a bottle mouth, and preventing occurrence of a hinging phenomenon or a loosely drawing phenomenon caused by the dispersion in hardness of the liner. <P>SOLUTION: In the cap material comprising a cap body having a disk-shaped top plate part and a peripheral wall part substantially hanging from a peripheral edge of the top plate part, and a sheet type liner 20 arranged along an inner surface of the top plate part of the cap body, the liner 20 comprises a sealing layer 21 having a seal function and a sliding layer 22 having a hardness higher than that of the sealing layer 21 and sliding with the inner surface of the top plate part while these layers are laminated on each other. At least one intermediate layer 23 is provided between the sealing layer 21 and the sliding layer 22, and the intermediate layer 23 has a hardness higher than that of the sealing layer 21 and lower than that of the sliding layer 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cap material and a cap-equipped container used for bottle cans, glass bottles, PET bottles, and the like.

  In recent years, openable and closable containers such as glass bottles, PET bottles, and aluminum bottle cans have been widely used as containers for beverages such as soft drinks. Cap materials used for these containers are widely provided with a cap body made of a synthetic resin or a metal cap such as an aluminum alloy or iron and a liner mainly composed of a synthetic resin. .

  The cap body generally includes a top plate portion and a peripheral wall portion substantially hanging from the peripheral edge portion of the top plate portion, and a slit portion extending in the circumferential direction and recessed inward in the radial direction on the lower end side of the peripheral wall portion. It is provided with easy break portions in which a plurality of bridges are alternately arranged in the circumferential direction. The cap material is obtained by mounting the liner on the inner surface of the top plate portion of the cap body.

  This type of cap material is placed on a bottle mouth portion having a male screw portion and a bulging portion that is arranged at the lower end of the male screw portion and bulges outward in the radial direction, and the top plate portion is pressed downward. In this state, the outer peripheral surface of the peripheral wall portion is pressed radially inward along the male screw portion of the bottle mouth portion to form a female screw portion on the peripheral wall portion. The open end portion (lower end portion) is pressed radially inward so as to be wound around the bulging portion (spin winding step), thereby being screwed into the bottle mouth portion and used as a cap. In other words, the cap is obtained by screwing the cap material onto the bottle mouth. Here, the inside of the bottle container is sealed by the close contact between the opening of the bottle mouth and the liner.

  The liner that is placed on the inner surface of the top plate of the cap body can be a resin that is bonded to the center of the inner surface of the top plate of the cap body after inserting a pre-formed disk, or resin on the cap body such as PVC sol. Into which the melted resin is adhered at the same time as the gelation, and the molten resin is put into the cap body and embossed. And most of these liners are bonded to the inner surface of the top plate portion of the cap body, and when rotating the cap, it is necessary to rotate the liner simultaneously with the cap.

  By the way, if the liner and the contact portion between the opening of the bottle mouth and the liner are strongly fixed, the frictional resistance between them is large, so the torque required for opening (hereinafter referred to as opening torque) is large. Therefore, there is a problem that the opening operation becomes difficult. Therefore, in order to reduce the opening torque, in order to improve the lubrication between the liner and the contact portion between the liner at the opening of the bottle mouth portion, a liner added with a lubricant is provided.

  However, when a liner to which a lubricant is added more than necessary is used, the liner to which the lubricant is added comes into direct contact with the filler in the bottle container, so that a part of the lubricant falls on the filler and the surface of the filler May be recognized as a foreign object and impair quality.

In order to solve such problems, in Patent Document 1, the liner has a two-layer structure of a functional layer and a support layer, and the sheet-like two-layer liner is not joined to the inner surface of the top plate portion of the cap body. Caps that are configured to be mounted have been proposed.
JP 2004-217295 A

By the way, a two-layer liner made of two types of resin is manufactured by forming a two-layer sheet material by a coextrusion method in which two types of synthetic resins are extruded and molded at once, and punching out the two-layer sheet material into a disk shape. Has been.
FIG. 5 shows a two-layer sheet material as a material for a conventional two-layer liner. The two-layer sheet material 1 has an elastomer layer 2 made of an elastomer having a low hardness and a plastic layer 3 made of a plastic having a high hardness, and a boundary between the elastomer layer 2 and the plastic layer 3 is present. A surface 4 is formed.

According to the co-extrusion method, the thickness of the entire sheet material 1 is maintained constant by roll rolling. However, when the MFR (JIS K 7210) of these two types of resins is different, these elastomer layer 2 and plastic The boundary surface 4 between the layers 3 may fluctuate so as to wave.
Since the elastomer layer 2 is made of a resin having a low hardness and the plastic layer 3 is made of a resin having a high hardness, the ratio in the thickness direction changes due to the fluctuation of the boundary surface 4, and the hardness of the sheet material 1 as a whole. Sometimes fluctuated greatly. In the liner manufactured by punching such a sheet material 1, the hardness may be partially different.

  When the cap material with the liner having a partially different hardness is screwed to the bottle mouth portion, the deformation resistance of the liner is partially different, so the open end of the peripheral wall portion in the skirt winding process The winding state of the portion may vary in the circumferential direction. When the skirt winding is insufficient, when the cap is opened, the bridge will not be cut and the cap will come off as it is, the so-called slipping phenomenon, or only some bridges will break and deform so that the mouth will open greatly There is a problem that a so-called hinge phenomenon occurs.

  The present invention has been made in view of the above circumstances, and even a liner having layers with different hardness can prevent variation in the hardness of the liner, and the cap material with the liner attached to the bottle mouth portion. It is an object of the present invention to provide a cap material and a cap-equipped container that can be securely attached and can prevent the occurrence of a hinged phenomenon or a slipping phenomenon caused by variations in liner hardness.

  In order to solve the above-described problems, the present invention provides a cap body having a disk-shaped top plate portion and a peripheral wall portion substantially hanging from the periphery of the top plate portion, and an inner surface of the top plate portion of the cap body. In the cap material provided with a sheet type liner disposed along the sealing layer, the liner has a sealing layer made of an elastomer and having a sealing function, a hardness higher than that of the sealing layer, and the top plate portion. An inner surface and a sliding layer that slides are laminated, and at least one intermediate layer is provided between the sealing layer and the sliding layer, and the intermediate layer has a higher hardness than the sealing layer. And having a lower hardness than the sliding layer.

In the cap material configured as described above, a multilayer liner having three or more layers having an intermediate layer between the sealing layer and the sliding layer is used as the liner. It is a multilayer sheet material of layers or more.
When such a multilayer sheet material is formed by a co-extrusion method, three or more kinds of resin materials are extruded simultaneously, and the respective boundary surfaces may wave. However, if the thickness of the entire sheet material is constant, the multilayer structure reduces the thickness of each layer, and the variation width of the thickness of each layer is reduced. Furthermore, since the intermediate layer is higher in hardness than the sealing layer and lower in hardness than the sliding layer, the hardness variation of the entire sheet material can be suppressed to a small value. Further, since it has a multi-layer structure of three or more layers, there are two or more boundary surfaces, and the plurality of boundary surfaces fluctuate, so that the variation in hardness of the entire sheet material is further reduced by these interactions. be able to.

In the cap material of this configuration, since the liner in which the hardness variation is suppressed as described above is mounted, the skirt is appropriately wound around the bulging portion when the cap material is screwed to the bottle mouth portion. Therefore, the occurrence of the slipping phenomenon and the hinge phenomenon of the cap material can be prevented.
Here, the hardness of the sealing layer is preferably 30 or less for Shore D (JIS K 6253) (80 or less for Shore A (JIS K 6253)) in consideration of adhesion to the bottle mouth. Further, the hardness of the sliding layer is preferably 40 or more on Shore D in order to ensure prevention of sticking to the inner surface of the top plate portion.

  In addition, by setting the thickness of the intermediate layer to 5% or more of the total thickness of the liner, the effect of reducing the variation in the hardness of the liner due to the intermediate layer can be reliably achieved. Furthermore, by setting the thickness of the intermediate layer to 80% or less of the total thickness of the liner, the thickness of the sliding layer and the sealing layer can be secured and the function as the liner can be secured.

Moreover, the bottle opening can be reliably sealed by setting the thickness of the sealing layer to 10% or more of the thickness of the entire liner. Furthermore, by setting the thickness of the sealing layer to 80% or less of the total thickness of the liner, the deformation resistance of the liner can be secured above a certain level, and the liner firmly adheres to the bottle mouth. Can be prevented from coming off the cap.

  Further, by making the thickness of the sliding layer 10% or more of the thickness of the entire liner, the effect of reducing the opening torque by the sliding layer can be surely achieved. Furthermore, by making the thickness of the sliding layer 65% or less of the thickness of the entire liner, it is possible to prevent the deformation resistance of the entire liner from becoming unnecessarily large.

  Further, by forming the intermediate layer with a blend material of the sliding layer and the sealing layer, the sheet waste after punching generated when the liner is punched and formed is reused as a raw material for the intermediate layer. Can do. Therefore, generation | occurrence | production of a waste can be reduced, while being able to make an environmental load small, the manufacturing cost can be reduced.

  Further, by adding a lubricant to the sliding layer, the frictional resistance between the liner and the inner surface of the top plate portion of the cap body is reduced by the lubricant, the opening torque can be reduced, and the opening can be easily performed. it can. Moreover, since the sliding layer is disposed so as to face the inner surface of the top plate portion of the cap material, it does not come into direct contact with the filler in the bottle container, and there is no possibility that the lubricant will float on the filler.

  Moreover, the cap of the present invention can be used as a cap for bottle containers such as aluminum bottle cans, PET bottles, tin free steel bottle cans and glass bottles by forming the cap body from aluminum alloy, synthetic resin, tinplate or tin-free steel. Material can be used.

  Further, the cap material is configured to rotatably support the liner by a knurled portion provided in the vicinity of the top plate portion of the cap body, so that the liner rotates together with the cap when the cap is rotated. Therefore, the opening torque can be greatly reduced and the opening can be facilitated.

  In addition, the cap-equipped container in which the cap material having the above-described configuration is disposed in the bottle mouth portion and the internal thread portion to be screwed to the bottle mouth portion on the inner surface of the peripheral wall portion has a small hardness variation of the liner. Can be performed uniformly and reliably in the circumferential direction, and there is no possibility of causing a slipping phenomenon or a hinge phenomenon when the cap is opened.

  Also, when opening the cap by rotating the cap, the side that contacts the inner surface of the top plate portion of the cap body and the inner surface of the top plate portion of the liner is a sliding layer, the dynamic friction coefficient between them is small, and the hardness of the sliding layer is The liner has a high deformation resistance and the liner is not firmly fixed to the inner surface of the top plate of the cap body, and the cap and liner can be moved relative to each other, allowing the sealing layer of the liner and the opening of the bottle mouth. There is no need to slide the contact portion of the portion with the sealing layer, the cap can be rotated, the opening torque is reduced, and the opening operation can be easily performed.

  As described above, according to the present invention, even a liner having layers having different hardnesses can prevent variations in the hardness of the liner, and the cap material to which the liner is attached can be securely attached to the bottle mouth. It is possible to provide a cap material and a container with a cap that can prevent the occurrence of a hinged phenomenon or a slipping phenomenon due to hardness variations.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a cap material 10 according to an embodiment of the present invention, and FIG. 2 shows a liner 20 used for the cap material 10.
The cap member 10 includes a cap body 11 formed by drawing an aluminum alloy plate and a liner 20 attached to the cap body 11.
The cap body 11 has a disk-shaped top plate portion 12 and a peripheral wall portion 13 that is substantially suspended from the peripheral edge of the top plate portion 12, and is recessed above the peripheral wall portion 13 on the inner surface side of the peripheral wall portion 13. The knurled portion 14 having a rectangular cross section and the liner support portions 15 that are recessed on the inner surface side of the peripheral wall portion 13 to form a triangular cross section and support the liner 20 from the lower surface side thereof are alternately arranged at equal intervals in the circumferential direction. ing.

  The liner 20 includes, for example, a sealing layer 21 made of an elastomer made of a polypropylene polymer, a sliding layer 22 made of a polypropylene (PP) plastic layer, and the sealing layer 21 and the sliding layer 22. In this embodiment, as shown in FIG. 2, it has a three-layer structure in which one intermediate layer 23 is provided.

  The total thickness of the liner 20 is preferably 0.5 mm to 1.5 mm, more preferably 0.7 mm to 1.3 mm, and in this embodiment, it is set to 1.0 mm. The thickness of the sealing layer 21 is set in the range of 0.1 mm to 0.8 mm, more preferably 0.1 mm to 0.4 mm, and the thickness of the sliding layer 22 is 0.1 mm to 0.65 mm. The thickness of the intermediate layer 23 is set within a range of 0.05 mm to 0.8 mm.

Here, the hardness of the sealing layer 21 is 30 or less in Shore D (JIS K 6253), and the hardness of the sliding layer 22 is 40 or more in Shore D. The intermediate layer 23 is set to have a hardness higher than that of the sealing layer 21 and lower than that of the sliding layer 22.
In this embodiment, the intermediate layer 23 is made of a blend material of a polypropylene polymer constituting the sealing layer 21 and a polypropylene constituting the sliding layer 22, and the hardness of the intermediate layer 23 is different from the hardness of the sealing layer 21. It is set to be an intermediate value with the hardness of the dynamic layer 22.

Here, 0.2% by weight of fatty acid amide is added to the sliding layer 22 as a lubricant, so that the surface of the sliding layer 22 is made slippery.
The liner 20 is disposed so that the sliding layer 22 made of a plastic layer faces the inner surface of the top plate portion 12, and is supported by the liner support portion 15. That is, the sliding layer 22 of the liner 20 and the inner surface of the cap material 10 top plate portion 12 are not joined.

  The liner 20 having a three-layer structure is manufactured by forming a three-layer sheet material by a co-extrusion method in which the three types of synthetic resins are extruded at once, and punching it into a disk shape. FIG. 3 shows a sheet material 24 that is a material of the liner 20 according to the present embodiment. This sheet material 24 has an elastomer layer 25 constituting the sealing layer 21, an intermediate resin layer 26 constituting the intermediate layer 23, and a plastic layer 27 constituting the sliding layer 22, and the elastomer layer 25 and the intermediate resin layer 26. A first boundary surface 28 is formed between the intermediate resin layer 26 and the plastic layer 27. A second boundary surface 29 is formed between the intermediate resin layer 26 and the plastic layer 27.

  Next, a capped bottle can 30 will be described as an example of a capped container in which the cap material 10 is used. As shown in FIG. 4, the cap-equipped bottle can 30 is configured by screwing a cap 40 onto a metal bottle can 31 (hereinafter referred to as a bottle can 31) formed of an aluminum alloy plate or the like. The bottle can 31 has a reduced diameter portion 33 that decreases in diameter upward from a cylindrical can body 32, and includes a cap portion 34 above the reduced diameter portion 33. The base part 34 includes a male screw part 35, a bulging part 36 that is connected to the lower end in the can axis direction of the male screw part 35 and bulges outward in the radial direction, and an upper end side in the can axis direction of the male screw part 25. And a curled portion 37 formed on the surface.

  The cap material 10 is used by being attached to the cap part 34 of the bottle can 31. That is, the cap material 10 is put on the base part 34 of the bottle can 31, and the periphery of the base part 34 is rotated in a state where the screw forming roller of the capping device is pressed against the peripheral wall part 13 of the cap material 10. By rolling along the male screw portion 35 of the cap 34, a female screw corresponding to the male screw portion 35 of the cap portion 34 is formed on the inner surface of the peripheral wall portion 13 of the cap material 10, and the open end portion of the peripheral wall portion 13 is formed. Is attached to the base part 34 and used as the cap 40 by being wound so as to be pressed radially inward so as to be wound around the bulging part 36 of the base part 24.

  That is, the cap 40 is formed by attaching the cap material 10 to the bottle can 31 and forming the female screw portion 41 on the peripheral wall portion 13 of the cap material 10. The cap 40 is formed with a top plate portion 12, a female screw portion 41, a pill fur proof portion 42, and a bridge portion 43, and the male screw portion 35 of the bottle can 31 and the female screw portion 41 of the cap 40. The cap 40 is attached to the bottle can 31 in a state where the lower end of the pill fur proof portion 42 is wound under the bulging portion 36, and the cap portion 34 of the bottle can 31 and the liner 20. The sealing layer 21 is sealed by being in close contact.

  When opening the bottle can 31 to which the cap 40 is attached, the cap 40 is rotated while the bottle can 31 is held at a fixed position. By this rotation, the pill fur proof portion 42 engaged with the bulging portion 36 of the bottle can 31 is separated by the bridge portion 43, and the portion other than the pill fur proof portion 42 of the cap 40 is the male portion of the base portion 34. It moves upward along the screw part 35. Along with this, the liner 20 held by the liner support 15 also moves upward, and the liner 20 and the base 34 are separated and opened.

  In the cap material 10 according to this embodiment, since the sheet material 24 having a three-layer structure is used as the material of the liner 20, when the sheet material 24 is formed by the coextrusion method, the MFR of the resin is different. The two boundary surfaces 28 and 29 may fluctuate so as to wave. Here, the sheet material 24 is set to 1 mm, the thickness of each of the sealing layer 21, the sliding layer 22, and the intermediate layer 23 is thin, and the fluctuation range of the thickness is also small in these layers. Therefore, variations in the first boundary surface 28 between the sealing layer 21 and the intermediate layer 23 and the second boundary surface 29 between the intermediate layer 23 and the sliding layer 22 are reduced, and the hardness of the entire sheet material 24 varies. Becomes smaller.

  Further, since the intermediate layer 23 is higher in hardness than the sealing layer 21 and lower in hardness than the sliding layer 22, variation in hardness of the entire sheet material 24 can be suppressed to be small. Further, the variation in the hardness of the entire sheet material 24 is further reduced by the interaction between the variation of the first boundary surface 28 and the variation of the second boundary surface 29. For this reason, the variation in the hardness of the liner 20 is also suppressed to a small level.

In the cap material 10 according to the present embodiment, since the liner 20 with reduced hardness variation is mounted in this way, when the cap material 10 is screwed to the base portion 34 of the bottle can 31, the peripheral wall portion 13. The open end portion of the cap member 10 can be reliably and stably wound around the bulging portion 36 of the base portion 24, and the occurrence of the slipping phenomenon and the hinge phenomenon of the cap material 10 can be prevented.
Further, since the liner 20 is provided with the sliding layer 22 that slides facing the inner surface of the top plate portion 12 of the cap body 11, the inner surface of the top plate portion 12 and the liner 20 are prevented from sticking, and the cap is opened. Torque can be reduced. Further, since the sealing layer 21 is provided on the liner 20, the opening of the base portion 34 can be reliably sealed by the liner 20.

  In addition, since the thickness of the sealing layer 21 is set within the range of 0.1 mm to 0.8 mm with respect to the thickness of the entire liner of 1.0 mm, the opening of the base 34 can be reliably sealed. The deformation resistance of the liner 20 can be ensured, and the liner 20 can be firmly fixed to the base part 34 and the liner 20 can be prevented from falling off the cap 40 when the cap is opened.

  Moreover, since the thickness of the sliding layer 22 is set within the range of 0.1 mm to 0.65 mm with respect to the thickness of the entire liner of 1.0 mm, the effect of reducing the opening torque by the sliding layer 22 is achieved. Can be surely successful.

  In addition, since the thickness of the intermediate layer 23 is set in the range of 0.05 mm to 0.8 mm with respect to the thickness of the entire liner 1.0 mm, the effect of reducing the variation in liner hardness due to the intermediate layer can be obtained. While being able to be surely successful, the thickness of the sliding layer 22 and the sealing layer 21 can be ensured to ensure the function as the liner 20.

  Further, since the sliding layer 22 is made of polypropylene, the sealing layer 21 is made of a polypropylene polymer, and the intermediate layer 23 is made of these blend materials, when the liner 20 is punched from the sheet material 24 Sheet waste generated in the above can be reused as a raw material for the intermediate layer 23. Therefore, generation | occurrence | production of a waste can be reduced, while being able to make an environmental load small, the manufacturing cost can be reduced.

  Furthermore, 0.2% by weight of fatty acid amide is added to the sliding layer 22 as a lubricant to prevent the sliding layer 22 from adhering to the inner surface of the top 10 of the cap material 10 and when the cap 40 is opened. A large force is unnecessary, and the cap opening property of the cap 40 is improved. Further, since the sliding layer 22 is disposed toward the inner surface of the cap member 10 top plate portion 12, the sliding layer 22 does not come into direct contact with the filler in the container, and the lubricant may float on the filler. There is no.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, in the present embodiment, a bottle can with an aluminum alloy cap is used for explanation, but the present invention is not limited to this. For example, a glass bottle with a metal cap attached, or a PET container made of resin. A cap may be attached.

  In the present embodiment, the entire liner has been described as having a thickness of 1.0 mm. However, the present invention is not limited to this, and the thickness of the entire liner is appropriately set according to the shape of the cap, the filler, and the like. It is preferable. Further, the thicknesses of the sliding layer, the sealing layer, and the intermediate layer may be arbitrarily set. However, in order to ensure the effect of the present invention, the thickness of the entire liner is preferably set within the range of the present embodiment when the thickness is 1.0 mm.

The thickness of the entire liner is preferably in the range of 0.5 mm to 2.5 mm. If it is less than 0.5 mm, when the liner is attached to the inner surface of the cap material top plate part, it will not be able to be securely hooked to the liner support part. This is because it becomes impossible to process. In consideration of the substantial use range, it is more preferable that the thickness of the entire liner is in the range of 0.5 mm to 1.5 mm.
Here, when the thickness of the entire liner is 0.5 mm, the thickness of the sealing layer and the thickness of the sliding layer are each 0.1 mm or more in order to ensure the functions of the sealing layer and the sliding layer. Further, in order to prevent the liner from falling off in close contact with the base portion, the combined thickness of the sliding layer and the intermediate layer is changed from 50% to 90% of the total thickness of the liner. It is preferable to set within the range of%.

  In addition, although the sliding layer is made of polypropylene, the present invention is not limited to this. For example, HDPE (high density polyethylene), LDPE (low density polyethylene), and L-LDPE (linear low density polyethylene). ), PET, PBT (polybutylene terephthalate), PA (polyamide), PC (polycarbonate), PS (polystyrene) resin, or the like.

  Moreover, although the elastomer which comprises a sealing layer was demonstrated as a polymer of polypropylene, it is not limited to this, For example, EVA (ethylene vinyl acetate copolymer) and HSBR (hydrogenated styrene butadiene copolymer) , Styrene elastomers such as SIS (styrene isoprene styrene copolymer), SBR (styrene butadiene rubber), SEBS (hydrogenated styrene ethylene butylene styrene copolymer), SEPS (styrene ethylene propylene styrene copolymer), EPDM (Ethylene propylene diene terpolymer) and olefin elastomer such as oil blend material, PVC (polyvinyl chloride) and plasticizer blend material of plasticizer, polyester elastomer, polyamide elastomer, etc. Of elastomer etc. It may have been made.

  Furthermore, although it demonstrated by what added 0.2 weight% of fatty acid amide as a lubricant to the sliding layer 22, it is not limited to this, The addition amount of a fatty acid amide is 0.01-1.0 weight% If it is in the range. Moreover, you may add an antiblocking agent instead of a fatty acid amide or in addition to a fatty acid amide. Here, for example, talc, mica, kaolin, diatomaceous earth, or the like may be added as an antiblocking agent in an amount of 0.3 to 5.0% by weight.

Below, the result of the comparative test conducted in order to confirm the effect of this invention is demonstrated.
In the comparative test, an aluminum alloy plate with a thickness of 0.25 mm, the inner and outer surfaces of which were coated with a synthetic resin paint, was molded into the cap body of a 38 mm PP cap, and a liner with the thickness of the sliding layer, intermediate layer and sealing layer changed. Insert the cap into an aluminum bottle can with a capacity of 300 ml and fill it with hot water at 80 ° C., drop liquid nitrogen so that the internal pressure of the head space becomes 1 kg / cm ² , The sample was plugged. The liner diameter was 37.5 mm, the knurled inner diameter was 35.5 mm, and the liner was set on the cap body with the sliding layer facing the inner surface of the top plate portion of the cap body. Here, when plugging with the cap, after confirming the state of the skirt winding, the conditions of the capping device were appropriately set according to the liner.
The sample was subjected to a retort treatment at 123 ° C. for 20 minutes and allowed to stand at room temperature (20 ° C.) for one day, and then the opening torque, drop impact property and sealing property were evaluated.

As the opening torque, the torque at the start of rotation (first torque) and the torque at the time of breaking the bridge portion (second torque) were measured.
The drop impact property was determined by checking the presence or absence of leakage by measuring the internal pressure of the bottle can after falling vertically on an iron board tilted at 10 ° with a drop height of 30 cm and allowing it to stand vertically.
In the evaluation of sealing properties, the number of occurrences of the hinge phenomenon and the supponke phenomenon for 100 samples was confirmed.

Table 1 shows the evaluation results when the thickness of the entire liner is 1.0 mm. Table 2 shows the evaluation results when the thickness of the entire liner is 0.7 mm. Table 3 shows the evaluation results when the thickness of the entire liner is 1.3 mm.
In Tables 1 to 3, PP1 is block type polypropylene (hardness Shore D65), elastomer-1 is a mixture of PP, SEPS and liquid paraffin (hardness Shore D25), and blending is a ratio of PP1 and elastomer 50 Blended in 50 pairs.

  When the total thickness of the liner is 1.0 mm, as shown in Table 1, in Comparative Examples 1 to 5 having no intermediate layer, the slipping phenomenon and the hinge phenomenon occur at a rate of several percent. It was confirmed that there was a problem with sealing properties. In Comparative Examples 6 to 10 in which the sliding layer is made of a resin whose hardness is lower than that of the intermediate layer even though the intermediate layer is included, no slipping phenomenon or hinge phenomenon is observed, and there is no problem in sealing properties. However, the first opening torque exceeded 200 N · cm, and there was a problem with the opening performance. This is because the hardness of the sliding layer is lowered and the friction with the inner surface of the top plate portion is increased.

On the other hand, in Examples 1 to 18 of the present invention, the opening torque is 154 N · cm or less for both the first and second, and the cap can be smoothly opened. Further, no leakage was observed in terms of drop impact. Further, no hingeing phenomenon or slipping phenomenon was observed, and it was confirmed that the sealing property was good.
However, in Example 19 of the present invention in which the sealing layer was 5%, no leakage was observed in terms of the drop impact property although no hingeing phenomenon or slipping phenomenon was observed. Therefore, the thickness of the sealing layer is preferably 10% or more of the entire liner thickness.

Further, even when the entire liner thickness was 0.7 mm and 1.3 mm, as shown in Tables 2 and 3, no problem was observed in the sealing property in the present invention example provided with the intermediate layer.
From the results of the above comparative tests, it was confirmed that the use of the liner of the present invention example can provide a cap material that is excellent in sealing performance and openability and that prevents the occurrence of the hinge phenomenon and the slipping phenomenon. .

It is a fragmentary sectional view of the cap material which is an embodiment of the present invention. It is explanatory drawing of the liner used for the cap material of FIG. It is explanatory drawing of the sheet | seat material which is the raw material of the liner shown in FIG. It is a fragmentary sectional view of a bottle can with a cap. It is explanatory drawing of the sheet | seat material which is the raw material of the conventional liner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cap material 11 Cap main body 12 Top plate part 13 Perimeter wall part 20 Liner 21 Sealing layer 22 Sliding layer 23 Intermediate layer 24 Sheet material 34 Base part (bottle mouth part)
40 caps

Claims (9)

A cap body having a disk-shaped top plate portion, a peripheral wall portion substantially hanging from the periphery of the top plate portion, and a sheet type liner disposed along the inner surface of the top plate portion of the cap body. In the cap material provided,
The liner is formed by laminating a sealing layer made of an elastomer and having a sealing function, and a sliding layer having a higher hardness than the sealing layer and sliding with the inner surface of the top plate portion,
At least one intermediate layer is provided between the sealing layer and the sliding layer, and the intermediate layer has higher hardness than the sealing layer and lower hardness than the sliding layer. Cap material characterized by that.   2. The cap material according to claim 1, wherein a thickness of the intermediate layer is set in a range of 5% to 80% of a thickness of the entire liner.   The cap material according to claim 1 or 2, wherein a thickness of the sealing layer is set in a range of 10% to 80% of a thickness of the entire liner.   The cap material according to any one of claims 1 to 3, wherein a thickness of the sliding layer is set in a range of 10% to 65% of a thickness of the entire liner.   The said intermediate | middle layer is comprised with the blend material of the said sliding layer and the said sealing layer, The cap material in any one of Claims 1-4 characterized by the above-mentioned.   The cap material according to any one of claims 1 to 5, wherein a lubricant is added to the sliding layer.   The cap material according to any one of claims 1 to 6, wherein the cap body is made of an aluminum alloy, a synthetic resin, tinplate, or tin-free steel.   8. The cap material according to claim 1, wherein the cap material is configured to rotatably support the liner by a knurled portion provided in the vicinity of the top plate portion of the cap body. The cap material described.   A container with a cap in which the cap material according to any one of claims 1 to 8 is disposed at a bottle mouth portion, and an internal thread portion is formed on the inner surface of the peripheral wall portion to be screwed onto the bottle mouth portion.

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