JP4481465B2 - Container lid with oxygen absorption - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a container lid having oxygen absorptivity, and more specifically, an oxygen-absorbing resin layer containing an oxygen absorbent in a portion facing the inner space of the container while being attached to the container mouth. It is related with the oxygen absorptive container lid in which is formed.
[0002]
[Prior art]
Packaging containers such as bottling always have a space called a head space inside the container after sealing, and the oxygen remaining in the head space accelerates the oxidative deterioration of the contents and is sufficiently satisfactory in terms of long-term storage. It wasn't. For this reason, an oxygen-absorbing container lid is proposed in which an oxygen-absorbing resin layer containing an oxygen absorbent is provided on the inner surface of the top plate portion of the container lid (the portion facing the inner space of the container) (for example, Japanese Patent Application 7-41930 publication etc.). In this oxygen-absorbing container lid, residual oxygen in the head space is removed by the oxygen-absorbing resin layer provided on the inner surface of the top plate, and as a result, the oxidative deterioration of the container contents is effectively suppressed.
In such an oxygen-absorbing container lid, it is preferable to increase the surface area of the oxygen-absorbing resin layer in order to increase the oxygen absorption rate by the oxygen-absorbing resin layer, and in the above Japanese Patent Publication No. 7-41930 In addition, it is described that minute irregularities are formed on the outer surface of the oxygen-absorbing resin layer (the surface on the side exposed in the container).
[0003]
[Problems to be solved by the invention]
However, there is a limit to increasing the surface area by forming fine irregularities on the outer surface of the oxygen-absorbing resin layer, and it is difficult to sufficiently increase the oxygen absorption rate.
Such an oxygen-absorbing resin layer is formed on the inner surface of the top plate portion of the container lid by an in-shell mold. That is, it is formed by dropping a melt of a resin composition containing an oxygen absorbent onto the center position of the inner surface of the top plate portion of a container lid formed by injection molding or the like, and pushing it out with a punch or the like. When the oxygen-absorbing resin layer is formed in this manner, the flow of the melt dripped at the center of the inner surface of the container lid is not effectively performed to the peripheral edge, and molding defects such as so-called resin breakage and uneven thickness are likely to occur. There was an inconvenience. In particular, when an uneven surface is formed on the outer surface of the oxygen-absorbing resin layer, there arises a disadvantage that the unevenness cannot be effectively formed on the peripheral portion.
[0004]
Accordingly, an object of the present invention is to provide an oxygen-absorbing container lid in which the surface area of the oxygen-absorbing resin layer is remarkably increased, the oxygen absorption rate is remarkably increased, and in addition, molding defects during in-shell molding are effectively prevented. There is.
Another object of the present invention is to provide an oxygen-absorbing container lid in which the sustainability of oxygen-absorbing characteristics is increased by increasing the volume of the oxygen-absorbing resin layer.
[0005]
[Means for Solving the Problems]
According to the present invention, the cap shell having a top plate portion and a skirt portion depending from the periphery of the top plate portion and an in-shell mold of a resin composition containing an oxygen absorbent are formed on the inner surface of the top plate portion of the cap shell. In the oxygen-absorbing container lid comprising the oxygen-absorbing resin layer,
On the inner surface of the top plate portion, a seal portion for sealing the container mouth portion is formed, and the oxygen-absorbing resin layer is formed on a portion surrounded by the seal portion on the inner surface of the top plate portion,
An oxygen-absorbing container lid is provided in which the peripheral edge of the oxygen-absorbing resin layer forms an annular protrusion hanging downward.
[0006]
Generally, an inner ring is formed on the inner surface of the top plate portion of the container lid so as to be in close contact with the inner surface of the container mouth wall, for example, a sealing portion for ensuring sealing performance. In other words, the container mouth wall is fitted between the skirt portion of the container lid and the inner ring, and the outer surface of the inner ring is in close contact with the inner surface of the container mouth wall, thereby ensuring a sealing property. In the oxygen-absorbing container lid of the present invention, the oxygen-absorbing resin layer is formed on the inner surface of the top plate portion surrounded by the seal portion formed by such an inner ring or the like. It is an important feature that the peripheral edge is an annular protrusion.
That is, by forming such an annular protrusion, the surface area of the oxygen-absorbing resin layer exposed in the inner space of the container (exposed surface area showing oxygen absorption characteristics) is remarkably increased. As a result, the oxygen absorption rate is significantly increased. It is done. Moreover, since the overall volume of the oxygen-absorbing resin layer is remarkably improved by forming such an annular protrusion, the oxygen-absorbing property is excellent in sustainability, and oxygen present in the head space of the container inner space is also improved. Can be captured over a long period of time, and such oxidative deterioration of the contents of the container due to oxygen can be effectively suppressed.
Furthermore, by forming the annular protrusion as described above, it is possible to effectively suppress molding defects when the oxygen-absorbing resin layer is formed by the inner mold. That is, when a melt of a resin composition containing an oxygen absorbent is dropped on the inner surface of the top plate portion and the melt is spread, a space for forming an annular protrusion is formed at the peripheral portion. As a result, the melt can be spread all over from the center to the peripheral edge, and molding defects such as resin breakage and uneven thickness can be effectively prevented.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on specific examples shown in the accompanying drawings.
FIG. 1 shows a side cross-sectional view of the oxygen-absorbing container lid of the present invention,
FIG. 2 shows a bottom view of the oxygen-absorbing container lid of FIG.
[0008]
1 and 2, the oxygen-absorbing container lid of the present invention is formed of a cap shell 1 indicated as a whole by 1 and an oxygen-absorbing resin layer 10 provided on the inner surface of the cap shell 1.
The cap shell 1 has a top plate portion 2 and a skirt portion 3 that hangs down from the periphery of the top plate portion 2, and a tamper evidence band is provided at the lower end of the skirt portion 3 through a weakening portion 4 such as a perforation. (TE band) 5 is provided. A plurality of flap pieces 6 are formed on the inner surface of the TE band 5 to engage with the container mouth (not shown). On the inner surface of the skirt portion 3, a screw portion 7 that engages with a screw portion (not shown) provided in the container mouth portion is provided.
Further, an inner ring 8 is formed on the inner surface side of the top plate portion 2 at an appropriate distance from the skirt portion 3, and on the inner surface of the top plate portion 2 located between the inner ring 8 and the skirt portion 3. Is formed with an annular outer protrusion 9.
[0009]
That is, when the container lid made of the cap shell 1 is attached to the container mouth portion by screw engagement between the screw portion 7 formed on the inner surface of the skirt portion 3 and the screw portion formed on the outer surface of the container mouth portion, The upper part of the container mouth part enters the space between the inner ring 8 and the annular outer protrusion 9, the upper end surface of the container mouth part abuts on the tip of the protrusion between the inner ring 8 and the annular outer protrusion 9, and The side surface of the upper end portion of the container mouth is in close contact with the outer side surface of the inner ring 8, thereby sealing the inside of the container.
On the other hand, when the container lid (cap shell 1) attached to the container mouth is swung to be removed from the container mouth (that is, when the container lid is opened), the cap shell 1 rises with the swivel. However, the TE band 5 connected to the lower end of the skirt portion 3 is restricted from rising because the flap piece 6 and the outer surface (particularly the jaw portion) of the container mouth portion are engaged. As a result, the weakened portion 4 connecting the lower end of the skirt portion 3 and the TE band 5 is broken, and only the TE band 5 remains in the container mouth portion. That is, the TE band 5 is peeled off from the cap shell 1 removed from the container mouth, and thus a general user can know whether or not the container lid has been opened.
[0010]
As the material constituting the cap shell 1 described above, all materials conventionally used for caps can be used. For example, olefin resins such as polyethylene, isotactic polypropylene, ethylene-polypropylene copolymer, polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, etc. And synthetic resins such as polystyrene, styrene-butadiene copolymer, ABS resin, and polycarbonate.
[0011]
In the present invention, the oxygen-absorbing resin layer 10 is placed on the portion of the cap shell 1 facing the inner space of the container, that is, the inner surface of the top plate portion 2 and surrounded by the inner ring 8. It is formed by a shell mold.
The oxygen-absorbing resin layer 10 is obtained by blending an oxygen absorbent in a thermoplastic resin that can be molded by an in-shell mold. The oxygen-absorbing resin layer 10 is present in the head space in the container. Oxygen is absorbed and deterioration of the container contents due to this oxygen is suppressed.
[0012]
As such an oxygen absorbent, all the oxygen absorbents conventionally used for this kind of application can be used. In general, those which are reducible and substantially insoluble in water are preferable. Suitable examples thereof include reducible metal powders such as reductive iron, reductive zinc, reducible tin powders; , For example, ferrous oxide, triiron tetroxide; reducing metal compounds, for example, one or a combination of iron carbide, silicon iron, iron carbonyl, iron hydroxide and the like, and polymers having polyvalent phenol in the skeleton Compounds such as polyphenol-containing phenol-aldehyde resins, ascorbic acid, erythorbic acid, hydroxycarboxylic acid or salts thereof can also be used.
Such an oxygen absorber is usually present in the oxygen-absorbing resin layer 10 in an amount of 5 to 40% by weight, particularly 5 to 25% by weight, depending on the type. When the amount of the oxygen absorbent is larger than the above range, it becomes difficult to form the oxygen-absorbing resin layer 10 on the inner surface of the top plate portion 2 by the in-shell mold. Absorption characteristics tend to be unsatisfactory.
[0013]
The thermoplastic resin to be blended with the oxygen absorbent may be any one as long as in-shell molding is possible. For example, polyethylene, isotactic polypropylene, propylene-ethylene copolymer, polybutene-1, ethylene -Olefin resins such as butene-1 copolymer, propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ion-crosslinked olefin copolymer (ionomer); ethylene-propylene-diene copolymer rubber And rubber olefin elastomers such as hydrogenated ethylene-propylene-diene copolymers; one or more kinds of soft plastics such as SBS elastomer, butyl rubber, SBR, and soft vinyl chloride resin.
[0014]
In the present invention, an annular protrusion 10 a that hangs downward is formed on the peripheral edge of the oxygen-absorbing resin layer 10, and there is a gap between the outer surface of the annular protrusion 10 a and the inner surface of the inner ring 8. Is formed.
That is, in such an annular protrusion 10a, both the inner surface and the outer surface are exposed in the container inner space, so that the surface area of the oxygen-absorbing resin layer 10 exposed in the container space is remarkably increased, and the oxygen absorption rate is significantly increased. Enhanced. Further, since the entire volume of the oxygen-absorbing resin layer 10 is remarkably increased by forming the annular protrusion 10a, the sustainability of the oxygen-absorbing characteristic is remarkably enhanced.
[0015]
In addition, by forming the annular protrusion 10a as described above on the periphery of the oxygen-absorbing resin layer 10, it is possible to effectively prevent molding defects during in-shell molding.
That is, the oxygen-absorbing resin layer 10 is formed by molding the above-described cap shell 1 by integral molding such as compression molding, and then, using the melt of the thermoplastic resin composition containing the above-described oxygen absorbent, the top plate portion of the cap shell 1. 2 is formed by dropping it on the center and spreading it with a punch or the like, but when forming the annular protrusion 10a at the peripheral edge, a space for forming the annular protrusion 10a is provided at the time of forming. It is done. Therefore, the space for forming the annular protrusion 10a provided at the peripheral portion becomes an escape route of the melt, and as a result, the melt flows uniformly from the center to the peripheral portion, and molding defects such as resin breakage and thickness unevenness are effective. It is prevented by this.
[0016]
In the present invention, there is no particular limitation on the length of the annular protrusion 10a described above, but it is usually preferable to be about 2.0 to 5.0 mm. Further, the thickness d of the annular protrusion 10a is preferably 0.8 mm or more, particularly in the range of 1.0 to 4.0 mm. If this thickness d is too small, the escape of the melt during the in-shell molding will not be performed effectively, which may be insufficient to prevent molding defects. Even if the thickness d is set larger than necessary, the amount of resin only increases, which is economically disadvantageous.
[0017]
In the present invention, the above-described oxygen-absorbing resin layer 10 is formed by an in-shell mold by dropping a resin melt on the inner surface of the top plate portion 2, so that as shown in FIG. 1 or FIG. A substantially circular flat surface 15 is formed at the center of the outer surface of the layer 10 surrounded by the annular protrusion 10a. That is, in order to spread the dropped resin melt with a punch or the like, the substantially circular flat surface 15 as described above is formed at the center portion corresponding to the pressing surface of the punch.
Further, it is preferable that an uneven surface 16 is formed around the flat surface 15. By forming such an uneven surface 16, the surface area of the oxygen-absorbing resin layer 10 exposed in the space in the container is further increased, and the oxygen absorption rate is increased.
[0018]
As shown in FIG. 2, the uneven surface 16 is preferably formed of a concentric annular uneven surface 16a and a plurality of ribs 16b extending radially in a radial direction at appropriate intervals. It is.
That is, the surface area of the oxygen-absorbing resin layer 10 is remarkably increased by the annular concavo-convex surface 16a, and the radial ribs 16b promote the flow of the resin melt to the peripheral edge during the in-shell molding, thereby making the molding defect more effective. Can be prevented. Of course, the number of the radial ribs 16b is not limited to this, but is preferably about 4 to 12, and the depth of the annular uneven surface is about 0.5 to 2.5 mm. (Or the number of protrusions) is preferably about 4 to 12.
[0019]
In addition, it is preferable that the thickness p of the part enclosed by the cyclic | annular protrusion part 10a of the oxygen absorptive resin layer 10 mentioned above is about 1.0 thru | or 2.0 mm normally. If this thickness is too thin, it may be difficult to effectively flow the peripheral edge of the melt during in-shell molding. On the other hand, if it is too thick, the mandrel needs to be replaced during printing, which may reduce the production speed. That is, this container lid is printed with a mark such as a trademark on the outer surface of the top plate portion 2 prior to being marketed. This printing is performed using a printing roller or the like with the container lid held at the tip of the mandrel. Therefore, if the thickness p of the oxygen-absorbing resin layer 10 is set to be excessively large, the mandrel must be replaced during printing to adjust the height of the container lid held at the tip of the mandrel. If the thickness p is set in the above-described range, printing can be effectively performed only by adjusting the pressure of the printing roller without replacing the mandrel.
[0020]
In the example of FIGS. 1 and 2 described above, the TE band 5 is provided at the lower end of the skirt portion 3 of the cap shell 1. However, the present invention naturally includes a container lid that is not provided with such a TE band 5. Can also be applied. Further, the seal portion for sealing the container mouth portion is formed by the inner ring 8. Instead of such an inner ring 8, a soft or rubber-like donut-shaped sealing material is provided on the peripheral portion of the top plate portion 2. It is also possible to form a seal portion by providing and bringing the upper end of the container mouth portion into close contact with such a seal material.
[0021]
【The invention's effect】
In the oxygen-absorbing container lid of the present invention, an oxygen-absorbing resin is formed by forming an annular protrusion on the periphery of the oxygen-absorbing resin layer formed on the inner surface of the top plate portion surrounded by a seal portion such as an inner ring. The surface area of the layer can be significantly increased and the oxygen absorption rate can be significantly increased. In addition, since the entire volume of the oxygen-absorbing resin layer is significantly improved, the sustainability of the oxygen-absorbing characteristics can be significantly increased.
Furthermore, the formation of the annular protrusion can effectively suppress molding defects when the oxygen-absorbing resin layer is formed by the inner mold.
[Brief description of the drawings]
FIG. 1 is a side sectional view of an oxygen-absorbing container lid according to the present invention.
2 is a bottom view of the oxygen-absorbing container lid of FIG. 1. FIG.
[Explanation of symbols]
1: Cap shell 2: Top plate portion 3: Skirt portion 8: Inner ring 10: Oxygen-absorbing resin layer 10a: Annular projection 16: Concavity and convexity

Claims (5)

An oxygen-absorbing resin layer formed on the inner surface of the top plate portion of the cap shell by an in-shell mold of a resin composition containing a cap shell having a top plate portion and a skirt portion suspended from the periphery of the top plate portion and an oxygen absorbent In an oxygen-absorbing container lid consisting of:
On the inner surface of the top plate portion, a seal portion for sealing the container mouth portion is formed, and the oxygen-absorbing resin layer is formed on a portion surrounded by the seal portion on the inner surface of the top plate portion,
An oxygen-absorbing container lid, wherein the peripheral edge of the oxygen-absorbing resin layer forms an annular projecting portion that hangs downward. The seal portion is an inner ring formed integrally with the inner surface of the top plate portion, and the annular protrusion on the periphery of the oxygen-absorbing resin layer is formed at a distance from the inner surface of the inner ring. 2. The oxygen-absorbing container lid according to 1. The oxygen-absorbing container lid according to claim 1 or 2, wherein the annular protrusion has a thickness in a range of 0.8 to 4.0 mm when viewed from a side cross section. The oxygen-absorbing container lid according to any one of claims 1 to 3, wherein an uneven surface is formed on an outer surface of the oxygen-absorbing resin layer surrounded by the annular protrusion. The uneven surface formed on the outer surface of the oxygen-absorbing resin layer is formed of concentric annular unevenness and a plurality of radial ribs extending radially from a central portion of the oxygen-absorbing resin. 4. The oxygen-absorbing container lid according to 4.

Images