JPH04327149A - Container cap with fast oxygen absorption property - Google Patents

Abstract

PURPOSE:To remove residual oxygen fast out of a container and to prevent deterioration of quality and decline of flavor from occurring to substance enclosed in the container by a method wherein minutely rugged face is formed on the surface of an oxygen-absorbing resin composition provided either on a resin liner or a packing so that the rugged face covers almost entirely the surface on its central part facing the inside of the container. CONSTITUTION:A container cap 1 is type of crown cap and is made up of a container cap shell body 2 and a sealing liner 3 that is provided on the inside of the shell body 2, which is formed of a top board part 4 and its circumferential skirt part 5 that are made up by integrally forming metal or the like. The sealing liner 3 is provided on a part that is provided on the inside of the shell body 2 for engagement with a mouth of the container, and the liner is made of oxygen absorbing resin composition, in which deoxygenation agent is mixed for dissipation of the oxygen. The liner 3 is equipped with a central part 7 that is smaller than a surrounding sealing part 6 for engagement with the mouth of the container, and is exposed to the inside of the container. Minutely rugged face 8 is formed over the surface of the central part 7.

Description

Detailed Description of the Invention [0001] [Industrial Application Field] The present invention relates to a lid for a bottle or other container, and more specifically to a lid for a bottle or other container. The present invention relates to a rapid oxygen-absorbing container lid that can quickly remove oxygen. [0002] In the production of canning and bottling, there is always a space called a head space at the top of the bottle. Oxygen remains in the head space after capping, which oxidizes and degrades the contents and causes the growth of mold, yeast, bacteria, etc. In order to remove oxygen from the headspace, it is generally known that water vapor or nitrogen gas is blown into the filled bottle, replacing the air in the headspace with these gases, and then capping the bottle. ing. Gas displacement is advantageous in that it removes some oxygen from the headspace. [0003] However, gas replacement requires a large amount of money for gas and equipment. Further, even with gas replacement, it is difficult to completely remove oxygen in the head space, and even more so, it is extremely difficult to remove dissolved oxygen from the contents. In fact, when fruits, fruit juices, vegetables, etc. are packaged in cans or bottles, it is known that residual oxygen causes deterioration of the contents. [0004] On the other hand, in order to prevent the effects of residual oxygen in the container, there are already known containers in which an oxygen absorbent is used in the lid or the like. For example, there is a case where the container lid consists of a metal shell and a gasket or liner provided inside the shell, and the resin of the gasket or the like is blended with an oxygen absorbent. Oxygen absorbers in container lid liners or gaskets ultimately absorb and remove residual oxygen in the headspace or contents. [Problems to be Solved by the Invention] However, the known oxygen absorbent-containing liner does not remove residual oxygen in the container from immediately after capping until the contents are sterilized or sterilized without affecting flavor, etc. The ability to remove within a certain range has not yet been fully satisfactory. It is known that the flavor retention of the contents is closely related to the residual oxygen concentration during sterilization or sterilization by heating. What is desired is a liner containing an oxygen absorbent that can remove the [0006] An object of the present invention is to provide a container lid that can quickly remove residual oxygen within the container and thereby prevent the contents from deteriorating and flavor from deteriorating. Another object of the present invention is to provide a container lid equipped with an oxygen absorbent-containing liner or packing that has a simple structure, is easy to manufacture, and has an excellent initial absorption rate of residual oxygen in the container. [Means for Solving the Problems] The present invention relates to a container lid consisting of a container lid shell and a resin liner or packing provided on the inner surface of the shell. A layer of an oxygen-absorbing resin composition containing an oxygen scavenger is provided in the container, and minute irregularities are formed on the surface of the oxygen-absorbing resin composition layer on the inner surface of the container over almost the entire surface of the container closer to the center than the sealing part. let Although the uneven surface of the oxygen-absorbing resin composition layer on the inner surface of the container may be exposed on the inner surface of the container, it is preferably covered with a thin oxygen-permeable resin film for preventing elution. [Function] The present inventors have discovered that if oxygen in the headspace remains at a high concentration for a long period of time after sealing, the aroma components of the contents will be significantly reduced, or simply due to normal gas replacement or desorption. If only a certain amount of oxygen is removed by air and sealed, problems will arise with the quality of the contents.As a result of our research to solve these problems, we have developed an oxygen-absorbing resin layer on the liner or packing. It has been found that the absorption rate of oxygen in the head space can be increased by making the inner surface of the container a micro-rough surface. In the present invention, the absorption of oxygen in the headspace by the oxygen-absorbing resin layer occurs through a chemical reaction between the oxygen scavenger blended therein and oxygen, but the rate-determining conditions for the oxygen absorption rate are as follows: Both the diffusion rate from the surface of the oxygen-absorbing resin layer to the oxygen scavenger and the reaction rate between the oxygen scavenger and oxygen are considered. [0010] In the present invention, by forming minute irregularities on the inner surface of the container of the oxygen-absorbing resin layer, the surface area of the surface increases considerably compared to the case where the surface is flat, and as a result, the The amount of oxygen permeation into the layer increases. In addition, if the surface area is increased by forming microscopic irregularities,
The number of oxygen scavenger particles located near the surface increases dramatically, and the diffusion rate increases. [0011] In addition, the chemical reaction between the oxygen scavenger and oxygen is as follows:
The presence of water is important, and the amount of water has a large effect on the reaction rate. According to the present invention, by forming minute irregularities on the inner surface of the container of the oxygen-absorbing resin layer to increase its surface area, the permeation of water to the oxygen scavenger also increases, which leads to a reaction between the oxygen scavenger and oxygen. The speed will also increase. [0012] According to the present invention, as a result of the above, it is possible to quickly absorb oxygen in the head space, and as a result, the oxygen partial pressure in the head space is reduced, so that the dissolved oxygen in the contents is reduced. is released into the headspace, thereby making it possible to prevent the contents from deteriorating and off-flavoring. Preferred Embodiments of the Invention [Container Lid Shell] The container lid of the present invention is of course applicable not only to lids for bottle-shaped containers, but also to various container lids known per se, such as various can lids and heat seal lids. It can be applied, but
It is particularly useful as a lid to a container where the area of the liner or packing exposed to the head space within the container is relatively small. In other words, in containers such as bottles, the opening of the container is narrowed to a small diameter, and the lid of the container is also small in diameter. Therefore, the area exposed to the head space of the liner or packing is small, but the oxygen absorption By forming minute irregularities on the inner surface of the container of the resin layer and increasing the surface area, oxygen in the head space can be well absorbed even if the exposed area of the liner or packing is small. [0014] The container lid shell should have such rigidity that the sealing by the liner or packing is maintained regardless of the pressure difference between the inside and outside of the container, and is made of various metals, plastics, or a composite thereof. It is better. As the metal, a light metal plate such as aluminum or aluminum alloy, or a surface-treated steel plate such as tinplate or stain-free steel is used. Examples of the plastic include high-density polyethylene, polypropylene, thermoplastic polyester, polyamide, and styrene resin. The shape of the shell may be a crown, a screw cap, a pilfer-proof cap, a lug cap, a white cap, a tab tear-open cap, or the like. [Liner or Packing] In the present invention, a liner refers to something that is applied to a container lid shell and is formed into the shape necessary for sealing on the spot, while a packing is something that is formed into a predetermined shape outside the container. and then applied to the container. These liners or packings are resins or rubbers, or laminates of these with paper, metal foil, etc., as long as they satisfy the condition that they have an oxygen-absorbing resin layer at least on the center side of the sealed part. be able to. The liner or packing may be made of an oxygen-absorbing resin alone, or may be made of a composite of an oxygen-absorbing resin and another liner or packing material. [0016] The oxygen-absorbing resin is composed of a resin containing an oxygen scavenger, but it may also be a composition in which an oxygen oxidation catalyst is blended with the resin so that the resin itself is oxidized. The former is generally preferred. Oxygen scavengers include inorganic and organic oxygen scavengers. Further, an accelerator for promoting the deoxidizing effect may be added together with the deoxidizing agent. The accelerator may directly contribute to deoxidation or may act to improve the oxygen permeability coefficient and water adsorption. The oxygen-absorbing resin composition has an oxygen permeability coefficient of 10-12 cc・cm/cm2・sec・cmHg at 20°C and 0%RH.
It is preferable that the composition is made by blending an oxygen scavenger with a resin that has a water adsorption amount of 1% or more in pure water at 20°C. Examples of oxygen scavengers are: (A) Inorganic oxygen scavenger Inorganic oxygen scavengers include iron group metals such as iron powder or iron powder coated with metal halides, iron carbide, silicon iron, and other iron group metals. Metal alloy; ferrous sulfate, ferrous chloride
Examples include compounds of divalent iron group metals such as iron and ferrous oxide, and these are preferably used together with the accelerator described below. The oxygen scavenger may be water-soluble or insoluble, but in order not to impair the flavor retention of the contents, it is desirable to use a water-insoluble oxygen scavenger. It is also possible to use a granular oxygen scavenger by kneading it into the resin to prevent it from eluting. (B) Organic oxygen scavenger Specific examples of organic oxygen scavengers include polyhydric phenols such as catechol and pyrogallol, phenolic resins, ascorbic acid, erythorbic acid, tocopherol, etc., glucose, fructose, and galactose. , maltose, cellobiose, and their enzymes, hydroquinone, gallic acid, and the like can be used. From the viewpoint of retaining the flavor of the contents and preventing migration or elution into the contents, the organic oxygen scavenger is preferably a phenolic resin that is insoluble in water and has a large molecular weight. Hydroquinone aldehyde resin is suitable as the phenolic resin. This oxygen scavenger consists of a resin having an oxygen-absorbing group on its molecular chain, particularly a hydroquinone aldehyde resin having a plurality of phenolic hydroxyl groups per ring in its phenol skeleton. The oxygen scavenger is blended in an amount of 0.1 to 100 parts by weight, particularly 5 to 50 parts by weight, per 100 parts by weight of liner resin. That is, when the amount of the oxygen scavenger is less than the above range, the residual oxygen absorption effect is unsatisfactory, while when it is more than the above range, the cushioning properties, elasticity, sealing action, etc. inherent to the sealant are impaired. become. [0021] In the present invention, an accelerator thereof can be added together with an oxygen scavenger. As the accelerator, an electron-donating substance that acts directly on the oxygen scavenger and a hydrophilic substance that causes the oxygen scavenger to contain water can be used. Such accelerators, in addition to the liner configurations described above, provide rapid oxygen removal. The electron donating substance is desirably blended in an amount of 1 to 1000 parts by weight, particularly 10 to 200 parts by weight, per 100 parts by weight of the oxygen scavenger. Electron-donating substances include sodium chloride, potassium chloride, calcium chloride,
Common materials such as sodium sulfate and sodium nitrate can be used. Further, organic oxygen scavengers or inorganic oxygen scavengers are usually significantly accelerated in alkaline conditions, and it is particularly desirable to use a solid base as a promoter. From the viewpoint of flavor retention and hygienic properties, the solid base is preferably water-insoluble, such as zinc oxide, magnesium carbonate, silicate, anion exchange resin, zeolite, melamine resin, urea resin, Examples include ammonia aresol resin. The hydrophilic substance can be provided as a dispersed phase in the resin to promote the oxygen absorption reaction of the oxygen scavenger. Hydrophilicity specifically includes the following, but these are based on the JIS standard test method.
It is desirable that the weight increase rate when immersed for a period of time is 1% or more, particularly 2.0% or more in practice. The hydrophilic substance is preferably a polymer in order to suppress dissolution, and for the purpose of promoting the oxygen absorption reaction, polyvinyl alcohol, methylcellulose, ethylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, etc. cellulose derivatives, partially saponified polyvinyl acetate, polyvinyl methyl ether, polyacrylic acid, polymethacrylic acid, vinyl methyl ether/maleic anhydride copolymer, polyvinylpyrrolidone, acrylamide/acrylate copolymer, acrylamide/methyllene Partially saponified bisacrylamide copolymer, saponified vinyl acetate/methyl acrylate copolymer, polyoxyethylene compound, polystyrene sulfonic acid, poly-2
-Acrylamido-2-methylpropanesulfonic acid, and hydrophilic polymer compounds such as gelatin, modified casein, modified starch, sodium alginate, and gum tragacanth are preferred. It is desirable that these polymers be blended in an amount of 1% by weight or more, particularly 10% by weight or more based on the total weight. [0025] The resin containing the oxygen scavenger or further the accelerator may be any resin, but it is preferably a resin commonly used for forming liners or packings. Such resins include resins or rubbers that are known per se and have appropriate elasticity and cushioning properties, particularly soft vinyl chloride resins, low density polyethylene, ethylene-vinyl acetate copolymers, and low-density polyethylene/ethylene-vinyl. Alcohol copolymer blend, ethylene-propylene copolymer, thermoplastic styrene-butadiene-styrene block copolymer, thermoplastic styrene-isoprene-styrene copolymer, ethylene-propylene rubber,
Ethylene-propylene-nonconjugated diene rubber, styrene-butadiene rubber, nitrile-butadiene rubber, butyl rubber, natural rubber, polybutadiene, chloroprene rubber
Examples include rubber, polyurethane, acrylic rubber, silicone rubber, etc. Among these, low-density polyethylene, ethylene/propylene copolymer rubber, vinyl chloride resin plastisol, and styrene-butadiene rubber (SBR), especially solvent type SBR, are suitable for container liners because of their excellent sealing properties and processability. There is. These can be used alone or in combination of two or more, if necessary. These resins or elastomers contain resin compounding agents known per se, such as plasticizers,
Fillers, colorants, heat stabilizers, blowing agents, crosslinking agents, etc. can be added according to known formulations. [0026] The liner or packing provided with the oxygen-absorbing resin layer can be formed by any method so as to form the above-mentioned finely uneven surface. For example, when a melted resin or plastisol is applied inside a container lid shell and pressed to form a liner, that is, in the case of an in-shell mold, a mold with minute irregularities formed on the mold surface is used. The minute irregularities on the mold surface are transferred to the oxygen-absorbing resin layer of the liner. For example, in the case of a liner such as polyethylene, a molten resin composition is applied to the inner surface of the container lid shell and pressed with a cooled mold to form the liner into a predetermined liner shape including minute irregularities. In the case of soft vinyl chloride resin, plastisol is applied by known means such as spin coating, and then pressed with a heated mold to form a predetermined shape. Further, in the case of packing, for example, an embossing roll or the like is used to form minute irregularities on the surface of the oxygen-absorbing resin layer of the packing. The liner or packing can be bonded to the lid shell using a known adhesive primer, thermoplastic or thermosetting adhesive, or by thermal bonding without using any special adhesive. Can be done. As already pointed out, the degree of minute irregularities is related to the increase in surface area, but when the actual surface area is S and the projected area of the surface is So, the ratio of S/So is 1.1 or more, especially when the The number should be 2 or more. So means the area when the surface is completely smooth. When this surface is exposed, measure it with a roughness meter to find the maximum height roughness (Hm
It is desirable to have a rough surface with ax) of 0.1 mm or more, particularly 0.5 mm or more. The pattern of minute irregularities may be arbitrary, for example, concentric circles, crosshatch, random irregularities, etc. In addition, the cross-sectional shape is V-shaped,
It is U-shaped, rectangular, etc. In the present invention, the oxygen-absorbing resin layer in the liner or packing may be exposed on the inner surface of the container, but if there is a possibility that the oxygen scavenger may be eluted before or after reacting with oxygen, Preferably, a thin coating layer for preventing elution is provided on the oxygen-absorbing resin layer. Of course, this coating layer is permeable to oxygen or even water vapor, but not to water as a liquid. A suitable coating layer has an oxygen permeability coefficient of 10 x 10-12 cc·c.
m/cm2・sec・cmHg or more, especially 50×10
-12cc·cm/cm2·sec·cmHg or more is desirable. Suitable elution prevention resins include polyethylene, soft vinyl chloride resin, various synthetic rubbers, porous polyolefins, silicone resins, etc.
The thickness is preferably 0 μm, particularly 2 to 20 μm. The coating film can be provided on the exposed surface of the liner in the form of a coating solution, film, or the like. [Example] FIGS. 1A, 1B, and 1C are side sectional views, partially enlarged sectional views, and views from the liner side of an example of a container lid according to the present invention, that is, a cap used for a bottle or the like. It is a plan view. In the specific example shown in FIG.
is a crown, which consists of a container lid shell 2 and a sealing liner 3 provided inside the shell. The shell 2 consists of a top plate (center panel) 4 integrally formed of metal or the like and a skirt 5 surrounding the top plate. A sealing liner 3 is provided on the inner surface of the shell 2 at a portion that engages with the container opening. The liner 3 is made of an oxygen-absorbing resin composition, and an oxygen scavenger is blended and dispersed in the resin composition. The liner 3 consists of a peripheral sealing part 6 that engages with the container mouth and a center part 7 that is inside the sealing part 6 and exposed to the inner surface of the container. A finely uneven surface 8 is formed on the surface. The resin composition containing an oxygen scavenger may be provided on the entire surface of the liner, or may be provided only on the center portion 7 of the liner exposed on the inner surface of the container. Forming the entire liner from a resin composition containing an oxygen scavenger has the advantage of easy manufacturing operations, while forming only the center portion from a resin composition containing an oxygen scavenger will result in a sealing area caused by the oxygen scavenger. Each has the advantage of having no impact on Inside the liner,
The sealing part 6 that engages with the container opening is raised higher than the center part 7, and this part 6 ensures reliable sealing with the container. Liner sealing part 6
may have a flat structure, but may also be provided with circumferential irregularities that engage with the mouth portion. FIGS. 2A and 2B are a side sectional view and a partially enlarged sectional view showing another embodiment of the container lid according to the present invention. The shell, liner resin composition, and shape are substantially similar to those in FIG. In this specific example, the container lid 1
The finely uneven surface 8 of the oxygen-absorbing resin composition is covered with a thin resin coating layer 9 for preventing elution. [Example 1] An oxygen-absorbing liner resin composition prepared by blending a predetermined oxygen-absorbing composition with various liner resin compositions was melt-extruded into an aluminum cap shell to form a cap with a liner. Created. On this occasion,
The bottom of the liner forming punch has concentric concave and convex grooves to increase the liner surface area. The surface area was varied by changing the interval between the same circular irregularities. Using these caps, ascorbic acid 28 mg% β-carotene 0.
1.0 liter polyethylene terephthalate containing an orange juice simulated solution consisting of an aqueous solution containing 5 mg%
PET) bottles were sealed, and changes in oxygen concentration in the bottles were measured at regular intervals. Headspace volume is 85ml. The model liquid itself also consumes oxygen and deteriorates.
It can be seen that with the liner-equipped cap of the present invention, the oxygen concentration within the bottle decreases quickly, and a considerable amount of oxygen is absorbed into the liner. It was also clear that increasing the surface area increased the oxygen absorption speed. The performance results are shown in Table 1. The performance of a cap with a punch-formed liner (S/SO = 1) with a flat bottom as a control product and the results of a cap with a liner with a flat bottom and no oxygen absorber as a reference product were combined. I wrote this. [Example 2] A mixture of an oxygen-absorbing composition in a plastisol whose main components are emulsion-polymerized polyvinyl chloride resin (PVC) and a plasticizer was lined on the cap shell, and the bottom part The mixture was heated and gelled while being pressed with a punch with an uneven surface. Furthermore, the inside of the skirt portion of the cap shell was lined with a donut-shaped sol containing no oxygen absorbent. The oxygen absorbent-containing sol has a circular shape with a diameter of 38 mm. As a control product, it is similar, but
A cap with a liner made using a punch with a flat bottom and a reference cap with a liner with a flat bottom and no oxygen absorber were made. Using these caps, a 1.0 liter glass bottle containing an orange juice simulated liquid was tightly closed. The residual headspace volume was 55 ml. The oxygen concentration in the container hetched space was measured at regular intervals and the results are shown in Table 1. Although the surface area was increased, the rate of oxygen reduction was clearly greater. [Example 3] A liner material (S/SO=2.0) made of a resin composition made of polyethylene/polyvinyl alcohol mixed with an iron-based oxygen absorbing composition according to Example 1 was used. The part of the cap that touches the bottle opening is lined with plastisol compound. Performance was evaluated in the same manner as in Example 1. Although the surface area of the oxygen-absorbing liner exposed to the headspace side was reduced by applying the lining agent, the performance decreased, but it showed better performance than the control product with a flat liner surface. Table 1 shows the results.
I wrote it down. [Example 4] According to Example 1, a cap having a liner with an uneven surface was prepared from a resin composition containing an iron-based oxygen absorber. A silicone resin solution was applied to this surface and dried and solidified. A PET bottle filled with the orange juice simulant was sealed with this cap, and the residual oxygen in the head space was measured at regular intervals. Although the oxygen absorption rate decreased due to the provision of the coating layer, it was clearly superior to the control cap made of the same material without the surface roughness. The results are shown in Table 1. [Table 1] [Effects of the Invention] According to the present invention, in a container lid consisting of a container lid shell and a resin liner or packing provided on the inner surface of the shell, the resin A layer of an oxygen-absorbing resin composition containing an oxygen scavenger is provided on the liner or packing, and a microscopic coating is applied to the inner surface of the container on the inner surface of the oxygen-absorbing resin composition layer over almost the entire surface of the inner surface of the oxygen absorbing resin composition layer closer to the center than the sealing part. By forming the unevenness, residual oxygen in the container could be quickly removed, thereby reducing deterioration of the contents and deterioration of flavor characteristics due to residual oxygen. [0038] Furthermore, by providing a thin oxygen-permeable elution-preventing resin film on the uneven surface of the oxygen-absorbing resin composition layer on the inner surface of the container, the oxygen scavenger is prevented from elution into the contents. As a result, flavor retention can be further improved.

[Brief explanation of the drawing]

FIG. 1 shows an example of a container lid according to the present invention, (A) (B)
) and (C) are a side sectional view, a partially enlarged sectional view, and a plan view seen from the liner side of this container lid.

FIG. 2 shows another embodiment of the container lid according to the present invention, (A)
and (B) are a side sectional view and a partially enlarged sectional view, respectively.

[Explanation of symbols]

1 Container lid, 2 Container lid shell, 3 Sealing liner, 4 Top plate part (center panel), 5 Skirt part, 6 Liner sealing part, 7 Liner center part, 8 Micro-irregular surface, 9 Thin layer for preventing elution Resin coating layer.

Claims (5)

[Claims] Claim 1: A container lid comprising a container lid shell and a resin liner or packing applied to the inner surface of the shell, wherein the resin liner or packing is made of an oxygen-absorbing resin containing an oxygen scavenger. A rapid oxygen composition comprising a layer of a composition, and a surface of the oxygen-absorbing resin composition layer on the inner surface of the container has minute irregularities formed over almost the entire surface of the oxygen-absorbing resin composition layer closer to the center than the sealing part. Absorbent container lid. 2. The container lid according to claim 1, wherein the surface has a roughness having a maximum height roughness of 0.1 mm or more as measured with a roughness meter. 3. The container lid according to claim 1, wherein the ratio S/So is 1.1 or more, where S is the surface area of the surface and So is the projected area of the surface. 4. The container lid according to claim 1, further comprising a thin oxygen-permeable elution-preventing resin layer provided on the oxygen-absorbing resin composition layer. Claim 5: The oxygen-absorbing resin composition is heated at 20°C and 0%
Oxygen permeability coefficient at RH is 10-12cc・cm/cm2
・The composition according to claim 1, comprising a thermoformable resin or a composition in which an oxygen scavenger is blended into a resin composition that is larger than sec cmHg and has a water adsorption amount of 1% or more in pure water at 20°C. container lid.