Cap, cap having inner plug, and container

Abstract

Provided are a cap, a cap having an inner plug, and a container that are capable of achieving both suppression of leakage of a content and suppression of cracks. More specifically, the present invention relates to a cap 30 that is used for a container 50 having a storage part 11 for storing a content, a mouth part 12 protruding from the storage part 11, an inner plug 40 attached to the mouth part 12, and said cap 30 for covering the mouth part 12 and the inner plug 40. The inner plug 40 has a hole 42 for extracting the content, and at least a portion of the inner plug 40 surrounding the hole 42 contains a cyclic olefin resin. The cap 30 has a protrusion 33 that is fitted into the hole 42, and at least the protrusion 33 of the cap 30 has a type D durometer hardness of more than 30 to less than 60.

Description

Cap, Cap with Inner Stopper, and Container

[0001] The present invention relates to a cap, a cap with an inner stopper, and a container.

[0002] Patent Document 1 describes an eye drop container provided with an inner stopper made of a resin composition containing a cyclic olefin copolymer and a polyethylene resin. For containers such as eye drop containers, in order to maintain the airtightness of the drug, a convex portion (boss portion) of the cap is fitted into the nozzle portion of the inner stopper (see, for example, paragraph 0032 of Patent Document 1).

[0003] Japanese Patent No. 7477319

[0004] In order to bring the fitting portion into closer contact, the outer diameter of the convex portion of the cap is designed to be larger than the inner diameter of the inner stopper nozzle. For this reason, strong stress is generated in the fitting portion. General-purpose resins such as polyethylene (PE) and polypropylene (PP) are relatively soft, so cracks do not occur even when strong stress is generated in the fitted member. When the inner stopper nozzle and the convex portion of the cap are formed of a hard resin, when excessively strong stress is generated, a phenomenon in which cracks (stress cracks) occur in the nozzle of the inner stopper may occur.

[0005] Furthermore, even if the cracks are so fine that they are difficult to detect optically, the cracks may be promoted when they come into contact with the content drug. If the cracks expand excessively, the airtightness of the drug cannot be maintained, which may lead to volatilization of water content or leakage of the contents. On the other hand, if the outer diameter of the convex portion of the cap is approximately equal to the inner diameter of the inner stopper nozzle, or the inner diameter of the inner stopper nozzle is larger than the outer diameter of the convex portion of the cap, so that strong stress is not generated in the fitting portion, there is a concern that the contents may leak.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cap, a cap with an inner stopper, and a container that can achieve both suppression of content leakage and suppression of cracks.

[0007] To solve the above problems, the present invention has the following configuration: [1] A cap for use in a container having a storage section for storing contents, a mouth protruding from the storage section, an inner stopper fitted to the mouth, and a cap covering the mouth and the inner stopper, wherein the inner stopper has a hole for removing the contents, at least the portion of the inner stopper surrounding the hole contains a cyclic olefin resin, the cap has a protrusion that fits into the hole, and at least the protrusion of the cap has a Type D durometer hardness greater than 30 and less than 60. [2] A cap with an inner stopper for use in a container having a storage section for storing contents, a mouth protruding from the storage section, an inner stopper fitted to the mouth, and a cap covering the mouth and the inner stopper, wherein the cap with an inner stopper consists of the inner stopper and the cap, the inner stopper has a hole for removing the contents, at least the portion of the inner stopper surrounding the hole contains a cyclic olefin resin, and the cap is the cap described in [1]. [3] A container having a storage section for storing contents, a mouth protruding from the storage section, an inner stopper fitted to the mouth, and a cap covering the mouth and the inner stopper, wherein the inner stopper has a hole for removing the contents, and at least the portion of the inner stopper surrounding the hole contains a cyclic olefin resin, and the cap is the cap described in [1]. [4] The container according to [3], wherein the storage section and the mouth have surfaces containing a cyclic olefin resin, at least on the side where the contents are stored.

[0008] According to the present invention, it is possible to achieve both the suppression of leakage of contents and the suppression of cracks.

[0009] This is a schematic diagram illustrating an example of a container. This is a partial cross-sectional view showing an example of a main body container having a storage section and a mouth. This is a partial cross-sectional view showing an example of a container with an inner stopper and cap attached.

[0010] The present invention will be described below based on preferred embodiments.

[0011] Figure 1 is a schematic diagram showing an example of a container. Figure 2 is a partial cross-sectional view showing an example of a main body container having a storage section and a mouth. Figure 3 is a partial cross-sectional view showing an example of a container with an inner stopper and cap attached. Note that the drawings are for conceptual explanation only, and the dimensions and proportions of the components may differ from the actual dimensions.

[0012] As shown in Figure 1, the container 50 of this embodiment has a storage section 11 for containing contents, a mouth section 12 protruding from the storage section 11, an inner stopper 40 fitted to the mouth section 12, and a cap 30 covering the mouth section 12 and the inner stopper 40. The cap with inner stopper 51 is a set consisting of the inner stopper 40 and the cap 30, and does not include the storage section 11 and the mouth section 12. Before being attached to the mouth section 12, the inner stopper 40 and the cap 30 of the cap with inner stopper 51 may be separated. In the illustrated example of the container 50, the storage section 11 and the mouth section 12 are integrated to constitute the main container 10. The integration of the storage section 11 and the mouth section 12 may be done during molding (integral molding) or after molding (joining, etc.).

[0013] As shown in Figure 2, it is preferable that the storage section 11 and the opening 12 have a content contact surface 16 containing a cyclic olefin resin, at least on the side where the contents are stored. The content contact surface 16 is the surface on which the storage section 11 and the opening 12 can come into contact with the contents. The situation in which the contents come into contact with the content contact surface 16 is not limited to when the container 50 is standing still, but also includes when the container 50 is inverted. Depending on the orientation of the container 50, the range in which the content contact surface 16 actually comes into contact with the contents may change.

[0014] The main container 10 in the illustrated example has a storage space 14 inside the storage section 11 for storing contents. The space between the storage section 11 and the opening 12 may have a portion where the shape changes continuously, such as a reduced diameter section 15. An inner stopper 40 is fitted to the inner circumferential surface 17 of the opening 12.

[0015] The contents are not particularly limited in their state, but examples include liquids such as solutions and dispersions. Fluid contents such as powders and granules may be contained in the containment section 11. The liquid contained in the contents may be an aqueous liquid containing water as a solvent, or an oily liquid containing an organic solvent or dispersion medium.

[0016] The illustrated container 11 and opening 12 consist of a laminated structure 20 having an inner layer 21 containing a cyclic olefin resin on the side where the contents are contained, and an outer layer 22 containing a polyethylene resin outside the inner layer 21. The contents contact surface 16 is provided on the inner layer 21. Although not specifically shown, the container 11 and opening 12 may also have a structure in which the contents contact surface 16 (inner surface) to the opposite surface (outer surface) consists of a single layer of cyclic olefin resin, rather than a laminated structure 20.

[0017] As shown in Figure 3, an inner stopper 40 is fitted to the opening 12. Note that in the main container 10 shown in Figure 3, the laminated structure 20, including the inner layer 21 and outer layer 22 shown in Figure 2, is not shown.

[0018] The inner stopper 40 has a hole 42 for removing the contents. At least the portion of the inner stopper 40 surrounding the hole 42 contains a cyclic olefin resin. This suppresses the sorption (absorption, adsorption) of the contents even when they come into contact with the inner stopper 40.

[0019] The contents to be contained in container 50 are not particularly limited, but include pharmaceuticals, cosmetics, food, drugs, etc. As mentioned above, it is suitable for liquids and other fluid contents. The contents to be dispensed at the time of use are not particularly limited, but include eye drops, nasal drops, ear drops, control solutions for in vitro diagnostic agents, calibration solutions, etc.

[0020] The cap 30 in the illustrated example has a top surface portion 31 that covers the upper side of the inner stopper 40, and a side surface portion 32 that is connected to the outer circumference of the top surface portion 31 and covers the outside of the mouth portion 12. The top surface portion 31 and the side surface portion 32 may be integrally molded by injection molding or the like.

[0021] The illustrated cap 30 has a protrusion 33 on the inner stopper 40 side of the top surface 31 and a rib 34 on the mouth 12 side of the side surface 32. The protrusion 33 and rib 34 may be made of the same material as the top surface 31 and side surface 32. In this case, the entire cap 30, including the protrusion 33 and rib 34, can be integrally molded by injection molding or the like.

[0022] In the container 50 of this embodiment, the cap 30 has a protrusion 33 that fits into the hole 42, and at least the protrusion 33 of the cap 30 has a Type D durometer hardness greater than 30 and less than 60. The Type D durometer hardness is preferably 32 to 58, more preferably 35 to 56, and particularly preferably 40 to 54. In the illustrated example, the protrusion 33 fits into the hole 42 of the nozzle 41 formed in the inner stopper 40 from the side of the tip 43. The outer diameter of the protrusion 33 is designed to be larger than the inner diameter of the hole 42.

[0023] The protrusion 33 of the cap 30 and the hole 42 of the inner stopper 40 engage to suppress leakage of the contents. However, as described above, since the inner stopper 40 contains a cyclic olefin resin, the part of the inner stopper 40 that contacts the protrusion 33 is harder than general-purpose resins (PE, PP), and there is a risk of stress cracks forming in the inner stopper 40. For this reason, in this embodiment, at least the protrusion 33 of the cap 30 is made of a resin whose Type D durometer hardness is within the range described above.

[0024] The resin constituting the cap 30 is not particularly limited as long as it satisfies the above requirements, but may be appropriately selected from polyolefin resins such as polyethylene resin and polypropylene resin. Threads (not shown) may be provided on the outer surface of the mouth portion 12 and the inner surface of the side portion 32 of the cap 30. The threads can be molded integrally with each component of the container 50 by resin molding.

[0025] The inner plug 40 in the illustrated example has a flange portion 44 that can contact the end portion 13 of the mouth portion 12, and a leg portion 45 that is inserted into the inside of the mouth portion 12. The shape of the flange portion 44 in a plane perpendicular to the central axis is not particularly limited, but a shape that is substantially similar to the cross-sectional shape of the mouth portion 12 is preferred, and examples include a circular shape and a polygonal shape. Furthermore, the inner plug 40 in the illustrated example is formed so that the hole 42 penetrates from the tip portion 43 that protrudes upward to the base portion 46 that protrudes downward.

[0026] The inner stopper 40 has a layer containing a cyclic olefin resin in at least the area that can come into contact with the contents. Here, the area that can come into contact with the contents also includes the inside of the hole 42. Furthermore, the entire inner stopper 40 may be formed from a resin containing a cyclic olefin resin.

[0027] The resin component constituting at least the area of ​​the inner stopper 40 that can come into contact with the contents may consist solely of a cyclic olefin resin, or it may be a mixture of a cyclic olefin resin and other resins. The resin component may contain two or more types of cyclic olefin resins. The proportion of cyclic olefin resin in the resin component is preferably, for example, 50 to 100% by weight.

[0028] Other resins that can be blended with the resin component in the inner stopper 40 include, for example, polyolefin resins such as polyethylene resin and thermoplastic elastomers such as styrene elastomers. The resin component may be a layer containing a cyclic olefin resin and a polyethylene resin, or it may be a cyclic olefin resin layer that does not contain polyethylene resin.

[0029] The molding method for the inner plug 40 is not particularly limited, but can be appropriately selected depending on the shape, structure, etc. of the inner plug 40, and examples include injection molding and extrusion molding. To form the hole 42 in the nozzle 41, for example, in an injection molding die, a pin-shaped member is inserted, molten resin is solidified around it to form the nozzle 41, and then the pin-shaped member is removed from the nozzle 41.

[0030] If the main container 10 has a laminated structure 20, the inner layer 21 is laminated at least from the inner surface of the storage section 11 to the inner surface of the opening 12. Furthermore, the inner layer 21 may be laminated from the inner surface of the storage section 11 to the end 13 of the opening 12.

[0031] The resin component constituting the inner layer 21 may consist solely of a cyclic olefin resin, or it may be a mixture of a cyclic olefin resin and other resins. The inner layer 21 may contain two or more types of cyclic olefin resins. The proportion of the cyclic olefin resin to the total weight of the inner layer 21 is preferably, for example, 50 to 100% by weight. Other resins that can be blended into the inner layer 21 include, for example, polyolefin resins such as polyethylene resin and thermoplastic elastomers such as styrene elastomers. The inner layer 21 may be a layer containing a cyclic olefin resin and a polyethylene resin, or it may be a cyclic olefin resin layer that does not contain polyethylene resin.

[0032] The outer layer 22 of the laminated structure 20 of the main container 10 can be made of any suitable molding resin, such as polyethylene resin, not just cyclic olefin resin. Furthermore, thermoplastic elastomers such as styrene elastomers may be added to these molding resins. The outer layer 22 may be a layer containing polyethylene resin and cyclic olefin resin, or it may be a polyethylene resin layer that does not contain cyclic olefin resin.

[0033] The thickness of the inner layer 21 is not particularly limited, but is preferably in the range of 50 to 1000 μm, and more preferably in the range of 100 to 400 μm. The thickness of the outer layer 22 is not particularly limited, but is preferably in the range of 150 to 1400 μm, and more preferably in the range of 200 to 1000 μm. The outer layer 22, as the outermost layer of the laminated structure 20, may further have an outer surface that can come into contact with the outside air. That is, the laminated structure 20 may have other layers outside the outer layer 22.

[0034] The laminated structure 20 may have one or more layers other than the inner layer 21 and outer layer 22, such as a reinforcing layer, a gas barrier layer, an ultraviolet absorbing layer, an oxygen absorbing layer, and a printed layer. When molding the laminated structure 20, it is preferable to use a combination of the inner layer 21 and the outer layer 22 that provides excellent adhesion to each other. Additives such as ultraviolet absorbers, oxygen absorbers, colorants, and stabilizers can also be added to the resin. The inner layer 21 can also be designed without additives. Additives may be added to the outer layer 22.

[0035] After forming the housing portion 11 and the opening portion 12, which include the inner layer 21 and the outer layer 22, other layers such as a printed layer may be added to the outside of the outer layer 22. The overall thickness of the laminated structure 20 is preferably in the range of 300 to 2000 μm. The housing portion 11 and the opening portion 12 may locally include areas that are thicker or thinner than those exemplified.

[0036] Methods for molding the main container 10 include multilayer blow molding, multilayer injection molding, and multilayer inflation molding. More specifically, multilayer blow molding includes direct blow molding and injection blow molding. In blow molding, the main container 10, including the housing portion 11 and the mouth portion 12, can be molded by blowing air into the parison and pressing it against the inner surface of the mold.

[0037] The cyclic olefin resin used in the housing section 11, the mouth section 12, and the inner stopper 40 is not particularly limited, but any resin containing a cyclic olefin as a constituent monomer is acceptable. The same type of cyclic olefin resin may be used for each of the housing section 11, the mouth section 12, and the inner stopper 40, or different types of cyclic olefin resins may be used.

[0038] The cyclic olefins used as constituent monomers for cyclic olefin resins are unsaturated hydrocarbons (olefins) having at least one ring structure. Examples include at least one vinylcycloalkane and its derivatives having cycloalkanes with 3 to 20 carbon atoms, monocycloalkene and its derivatives having 3 to 20 carbon atoms, and cyclic olefins having a norbornene skeleton (norbornene monomers).

[0039] Examples of norbornene monomers include bicyclo[2.2.1]-2-heptene (norbornene) and its derivatives. Examples of norbornene derivatives include compounds having substituents such as alkyl groups, such as alkylnorbornene; compounds having two or more unsaturated bonds, such as norbornadiene; and compounds having three or more ring structures, two of which constitute the norbornene skeleton.

[0040] Norbornene monomers having three or more ring structures include tricyclo[5.2.1.0 ２，６decene (dihydrodicyclopentadiene), compounds obtained by adding one or more molecules of cyclopentadiene to norbornene or dihydrodicyclopentadiene via Diels-Alder reaction (for example, tetracyclododecene, pentacyclopentadecene, hexacycloheptadecene, etc.), hydrogenated products thereof, isomers having different double bond positions, alkyl-substituted products, and the like.

[0041] Cyclic olefin resins are known as resins excellent in non-sorption properties (non-adsorption properties) and moisture resistance. Examples of the cyclic olefin resin include cycloolefin polymer (COP), cycloolefin copolymer (COC), homopolymers of cyclic olefins, and the like.

[0042] The COP only needs to be a copolymer of different cyclic olefins, and examples include copolymers of two or more cyclic olefins, or hydrogenated products thereof. It is preferable that the COP is an amorphous polymer, and it may be a ring-opened polymer of a cyclic olefin obtained by metathesis or the like, or a hydrogenated product thereof.

[0043] The COC only needs to be a copolymer of a cyclic olefin and an acyclic olefin, and examples include a copolymer of at least one cyclic olefin and at least one acyclic olefin, or a hydrogenated product thereof. It is preferable that the COC is an amorphous polymer, and it may be a copolymer of a cyclic olefin and ethylene, or a hydrogenated product thereof. Examples of the acyclic olefin copolymerized with the cyclic olefin include α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene, and alkenes such as 3-decene and 3-dodecene.

[0044] Among the resin compositions constituting the inner plug 40 (particularly, the region that can come into contact with the content), the resin component is preferably a mixture containing at least one cyclic olefin resin and at least one polyethylene resin. The proportion of the cyclic olefin resin is preferably 25 to 85 parts by weight based on 100 parts by weight of the resin composition, and more preferably the lower limit is 30 parts by weight or more.

[0045] Examples of the polyethylene resin used in the resin composition include ethylene homopolymer, linear low-density polyethylene obtained by copolymerizing ethylene with an α-olefin having 4 carbon atoms (such as 1-butene) (C4-LLDPE), linear low-density polyethylene obtained by copolymerizing ethylene with an α-olefin having 6 carbon atoms (such as 1-hexene) (C6-LLDPE), linear low-density polyethylene obtained by copolymerizing ethylene with an α-olefin having 8 carbon atoms (such as 1-octene) (C8-LLDPE), ethylene-vinyl acetate copolymer (EVA), and ethylene-vinyl alcohol copolymer (EVOH).

[0046] The proportion of the polyethylene resin in the resin composition is preferably 15 to 75 parts by weight relative to 100 parts by weight of the resin composition, and more preferably, the upper limit is 70 parts by weight or less. The total amount of the cyclic olefin resin and the polyethylene resin in the resin composition is preferably 80 to 100 parts by weight, more preferably the lower limit is 85 parts by weight or more, further preferably 90 parts by weight or more, and particularly preferably 95 parts by weight or more.

[0047] Heretofore, the present invention has been described based on preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the gist of the present invention. Examples of the modifications include addition, substitution, omission of components in each embodiment, and other changes.

[0048] Hereinafter, the present invention will be specifically described with reference to examples.

[0049] <Preparation of Container> A container was produced by molding an inner plug and a cap into the shape shown in Figure 3. As the material of the inner plug, a resin composition obtained by mixing cycloolefin polymer (COP) and linear low-density polyethylene (LLDPE) at a weight ratio of 6:4 was used.

[0050] The following commercially available resins were used as the cap material: (1) Novatec HD HM160 (manufactured by Nippon Polyethylene Co., Ltd.) as a single resin (2) Nipolon (registered trademark)-L Grade M70 (manufactured by Tosoh Corporation; hereinafter referred to as "M70") as a single resin (3) A resin obtained by mixing M70 and Nipolon (registered trademark)-Z HM300K (manufactured by Tosoh Corporation; hereinafter referred to as "HM300K") in a weight ratio of 75:25 (4) A resin obtained by mixing M70 and HM300K in a weight ratio of 50:50 (5) A resin obtained by mixing M70 and HM300K in a weight ratio of 25:75

[0051] In accordance with JIS K 7215 (Test Method for Durometer Hardness of Plastics), the tip of a durometer was pressed against the top surface (outer surface of the top) of the cap, and the Type D durometer hardness was measured. The following results were obtained: Resin (1): Type D durometer hardness = 60.0 Resin (2): Type D durometer hardness = 50.3 Resin (3): Type D durometer hardness = 48.5 Resin (4): Type D durometer hardness = 45.6 Resin (5): Type D durometer hardness = 30.0

[0052] <Evaluation of Stress Cracks> The presence or absence of stress cracks was checked using the following method. Step 1: Insert the inner stopper into the bottle. Step 2: Tighten the cap over the mouth of the bottle until it can no longer be turned to seal the container. Step 3: After storing the container at 50°C for 120 hours, open the cap and observe the tip of the nozzle of the inner stopper with a microscope to check for the presence or absence of cracks.

[0053] Thirty-two caps were prepared for each of the five types of cap materials, and the presence or absence of stress cracks was checked using the method described above. The results were as follows: Resin (1): Type D durometer hardness = 60.0, 23 cracks Resin (2): Type D durometer hardness = 50.3, 0 cracks Resin (3): Type D durometer hardness = 48.5, 0 cracks Resin (4): Type D durometer hardness = 45.6, 0 cracks Resin (5): Type D durometer hardness = 30.0, the resin was too soft, making it difficult to seal the container by tightening the cap.

[0054] In resin (1), the crack occurrence rate was 72%, but in resins (2) to (4), the crack occurrence rate was 0%. From this, it was found that stress cracking can be suppressed when the Type D durometer hardness is greater than 30 and less than 60.

[0055] <Evaluation of moisture retention performance> For the four types of cap materials, resins (1) to (4), when containers were made using the method described above, 3 mL of sterile water for injection was sealed in the bottles, and the moisture loss rate was measured after storing the sealed containers in an environment of 40°C and 25% RH for 90 days. As a result, even when caps were made from resins (2) to (4), the moisture loss rate was about 2% by mass, similar to that of caps made from resin (1), indicating sufficient moisture retention performance.

[0056] <Evaluation of Capping Pressure> When resins (1), (2), and (4) were used for the caps, the capping pressure was measured when the protrusion (boss) of the cap was pressed into the nozzle hole of the inner stopper. Specifically, the protrusion (boss) and the surrounding portion of the cap were cut out, and the pressing force (in N) when the protrusion (boss) was pressed into the nozzle hole was measured using a small universal testing machine (texture analyzer manufactured by Eiko Seiki Co., Ltd.) as the average value for a sample size N=2.

[0057] Resin (1): Type D durometer hardness = 60.0, capping pressure = 43.2 N Resin (2): Type D durometer hardness = 50.3, capping pressure = 40.8 N Resin (4): Type D durometer hardness = 45.6, capping pressure = 39.3 N

[0058] Regression analysis between capping pressure x and Type D durometer hardness y showed a high correlation (monotonically increasing) as follows: y = 3.7477x - 102.03, R ２ = 0.9925. This confirms that the harder the material, the more likely it is to crack.

[0059] 10...Main container, 11...Storage section, 12...Mouth, 13...End of mouth, 14...Storage space, 15...Reduced diameter section, 16...Contents contact surface, 17...Inner circumferential surface of mouth, 20...Laminated structure, 21...Inner layer, 22...Outer layer, 30...Cap, 31...Top surface, 32...Side surface, 33...Protrusion, 34...Rib, 40...Inner stopper, 41...Nozzle, 42...Hole, 43...Tip, 44...Flange, 45...Legs, 46...Base end, 50...Container, 51...Cap with inner stopper

Claims

A compartment for storing contents, The opening protruding from the aforementioned housing section, The inner stopper is fitted into the opening, A cap that covers the opening and the inner stopper, A cap used for a container having, The inner stopper has a hole for removing the contents, and at least the portion of the inner stopper surrounding the hole contains a cyclic olefin resin. The cap is characterized in that it has a protrusion that fits into the hole, and at least the protrusion of the cap has a Type D durometer hardness greater than 30 and less than 60. 　 A compartment for storing contents, The opening protruding from the aforementioned housing section, The inner stopper is fitted into the opening, A cap that covers the opening and the inner stopper, A cap with an inner stopper used for a container having, The aforementioned cap with inner stopper consists of the inner stopper and the cap, The inner stopper has a hole for removing the contents, and at least the portion of the inner stopper surrounding the hole contains a cyclic olefin resin. The cap with an inner stopper is characterized in that the cap is the cap described in claim 1. 　 A compartment for storing contents, The opening protruding from the aforementioned housing section, The inner stopper is fitted into the opening, A cap that covers the opening and the inner stopper, A container having, The inner stopper has a hole for removing the contents, and at least the portion of the inner stopper surrounding the hole contains a cyclic olefin resin. The container is characterized in that the cap is the cap described in claim 1. 　 The container according to claim 3, characterized in that the storage portion and the opening portion have a surface containing a cyclic olefin resin, at least on the side where the contents are stored.

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