JPH0640463A - Oxygen absorbing container lid and manufacture thereof - Google Patents

Abstract

PURPOSE:To endow the lid with an excellent oxygen absorbing function by providing a porous molded layer which contains free-oxygen absorber particles and thermo-plastic polymer particles, and for which at least one part of the surface of the free-oxygen absorber particles is exposed, on a liner made of a polymer which is applied on the inner surface side of a container lid shell body. CONSTITUTION:The container lid has a shell body 1 consisting of a top plate 2 and skirt part 3 formed of a metal or hard resin, and a liner 4 made of a thermoplastic polymer is provided on the inner surface side of the top plate 2. The liner 4 consists of an upper layer panel part 5, sealing part 6 and lower layer part 7, and the upper layer panel part 5 is formed of a porous molded body containing a free-oxygen absorber, and is provided in such a manner that it is exposed to the inside of a sealed container. The porous molded body 5 consists of free-oxygen absorber particles 10 and thermoplastic polymer particles 11 which are evenly mixed, and the free-oxygen absorber particles 10 are fixed by the thermoplastic polymer particles 11. In this case, at least one part, preferably almost all the part of the surfaces of the free-oxygen absorber particles 11 are exposed without being covered by the polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container lid with a liner having a high oxygen absorption property and a method for producing the same, and more particularly, it has a combination of a sealing property and a high oxygen absorption property.
The present invention relates to a liner-equipped container lid that can be easily manufactured and a manufacturing method thereof.

[0002]

2. Description of the Related Art In the production of hermetically sealed packages such as bottles, there is always a space called a head space above the bottle. Oxygen remains in the headspace after plugging, and oxygen causes oxidative deterioration of the contents, and further causes the growth of mold, yeast, bacteria and the like. In order to remove oxygen in the headspace, it is generally known that a bottle filled with contents is sprayed with water vapor or nitrogen gas to replace the air in the headspace with these gases, and then the lid is stoppered. ing. Gas replacement is excellent in that it removes oxygen in the headspace to some extent.

However, in order to carry out gas replacement, a large amount of cost is required for the gas cost and facilities. Further, even if the gas is replaced, it is difficult to completely remove oxygen in the head space, and much more difficult to remove even dissolved oxygen in the contents. In fact, it is known that canning and bottle filling of fruits, fruit juices, vegetables, etc. cause deterioration of the contents due to residual oxygen.

On the other hand, in order to prevent the influence of residual oxygen in the container, a device using an oxygen absorbent for the lid is already known. For example, there is one in which a container lid is composed of a metal shell and a gasket or liner provided inside the shell, and a resin such as the gasket is mixed with an oxygen absorbent. The oxygen absorber in the container lid liner or gasket ultimately absorbs and removes residual oxygen in the headspace or contents.

Japanese Patent Application No. 3-88 relating to the proposal by the present inventors
No. 592 is provided with a layer of an oxygen-absorbing resin composition in which a deoxidizer is mixed in a resin liner or packing, and the oxygen-absorbing resin composition layer is provided on the surface on the inner surface side of the container rather than the sealed portion. It has been proposed to improve the oxygen absorption rate by forming minute irregularities over almost the entire center side.

[0006]

The oxygen absorbent-containing liner found in the above proposal shows some improvement in the oxygen absorption rate, but the liner inside the container is closed immediately after stoppering and before sterilization or sterilization of the contents. The ability to remove the residual oxygen in the range to the extent that flavor and the like are not affected was not yet fully satisfactory. It is known that the flavor retention (flavor retention) of the contents is closely related to the residual oxygen concentration during sterilization or sterilization by heating.
There is a demand for an oxygen absorbent-containing liner that can remove residual oxygen in the container within a short time after plugging.

An object of the present invention is to provide a container lid which can remove residual oxygen in the container rapidly, thereby preventing deterioration of contents and deterioration of flavor, and a manufacturing method thereof. Another object of the present invention is to provide a container lid provided with an oxygen absorbent-containing liner that has a simple structure, is easy to manufacture, and has an excellent initial absorption rate of residual oxygen in the container.

Still another object of the present invention is to provide a container lid with a function-separated liner in which the oxygen absorbing function is highly exhibited without impairing the sealing performance, and a method for producing the same. Another object of the present invention is to provide a method capable of producing the container lid with a function-separated liner with excellent productivity and high quality.

[0009]

According to the present invention, a container lid comprising a container lid shell and a polymer liner provided on the inner surface side of the shell, wherein the liner is an oxygen scavenger Porous molded article containing particles and thermoplastic polymer particles, wherein the oxygen absorber particles are fixed via the thermoplastic polymer particles, but at least a part of the surface of the oxygen absorber particles is exposed. An oxygen-absorbing container lid is provided which is provided with a layer of.

In the present invention, it is preferable that the porous molded body is provided independently of the sealing portion of the liner, and in particular, the porous molded body is provided as the upper layer portion constituting the panel portion inside the sealing portion, and the cushioning property is provided. And a thermoplastic polymer having elasticity as a lower layer portion which is interposed between the upper layer portion and the shell top surface to join the two, and is integrated with the lower layer portion on the outer peripheral side of the panel portion. In addition, it is preferable to provide it as a sealing part formed so as to project above the panel part.

Further, according to the present invention, a melt of a thermoplastic polymer having cushioning properties and elasticity is supplied into the container lid shell body, and the deoxidant particles and the thermoplastic polymer particles are contained in the melt. Oxygen agent particles are fixed through the thermoplastic polymer particles, at least a portion of the surface of the oxygen scavenger particles is exposed panel-shaped disc of a porous molded body is located on the melt, This laminated body is pressed by a pressing die in the container lid shell to bond the panel portion to the shell top surface with a melt, and the melt is extruded to the outer periphery of the panel portion to form a sealed portion. A method for manufacturing an oxygen-absorbing container lid is provided.

In the present invention, the sheet of the porous molded body is supplied onto the container lid shell to which the melt of the polymer has been supplied, and the sheet is cut into a panel-shaped disc, and the cut disc is cut. Can be applied to the resin melt of the shell in the positioned state.

[0013]

In the present invention, the polymeric liner applied to the inner surface side of the container lid shell contains the oxygen absorber particles and the thermoplastic polymer particles, and the oxygen absorber particles contain the thermoplastic polymer particles. It is a distinctive feature to provide a layer of the porous molded body which is fixed through the layer, but has at least a part of the surface of the oxygen absorber particles exposed.

The reason why the liner using the layer in which the oxygen scavenger is dispersed in the resin is inferior in the rapid oxygen absorbing property is that the surface of the oxygen scavenger particles is covered with the resin and It is considered that the absorption is affected by the diffusion rate of oxygen in the resin. That is, in the resin oxygen scavenger particle dispersion system, the diffusion rate of oxygen in the resin is the rate-determining step,
Therefore, the absorption rate of oxygen becomes slow.

When the oxygen absorber particles are used without being embedded in the resin, the effect of oxygen diffusion in the resin could be eliminated, but in this case, they must be handled in the form of powder. This causes a problem that the oxygen absorber particles adhere to the member of the container lid or are mixed in the contents.

In the present invention, the oxygen scavenger particles and the thermoplastic polymer particles are used to produce a porous molded body in which these are integrated. In this porous compact, the oxygen absorber particles and the thermoplastic polymer particles are homogeneously mixed and evenly dispersed, but each of these particles maintains their independence as described below. Has been done. That is, the oxygen scavenger particles are fixed via the thermoplastic polymer particles, but at least a part of the surface of the oxygen scavenger particles, preferably most of the surface, is exposed.

The thermoplastic polymer particles act as a binder for fixing the oxygen absorber particles, but the essence of the particles has not yet been lost, and as a spacer for forming voids between the oxygen absorber particles. Also plays the role of. Therefore, in this molded body, a large number of communicating voids are formed inside, and the surface of the oxygen absorber particles is exposed to the voids. Oxygen flows from the surface of the porous molded body through the above-mentioned voids, and oxygen is absorbed from the surface of the oxygen absorber particles, so that the headspace or the content can be rapidly changed without being affected by the diffusion of oxygen in the resin. Oxygen remaining in the substance can be absorbed and removed.

Since the oxygen scavenger particles are solidified and integrated into one piece by the thermoplastic polymer particles, they are not only easy to handle as an integrated molded article, but also
There is no problem that the oxygen absorber particles are released in the form of powder and adhere to the member of the container lid or are mixed in the contents.

In the present invention, when the porous molded article containing the oxygen scavenger particles and the cushioning thermoplastic polymer constituting the liner are provided independently of each other, mutual influences are prevented and the oxygen generated by the oxygen scavenger particles is prevented. The absorbing effect and the sealing effect as the liner are mutually best achieved.

Next, by providing the oxygen scavenger-containing porous molded body as the panel portion inside the sealing portion in the upper layer of the liner, the oxygen scavenging is performed within a range that does not affect the sealing performance of the liner. The agent particle-containing porous molded body layer can be exposed in the maximum area in the container after sealing, whereby the deoxidizing action can be sufficiently exerted. On the other hand, on the outer peripheral side of the panel portion, a thermoplastic polymer having cushioning properties and elasticity is present so as to project above the panel portion to form a sealing portion, so that excellent sealing performance is obtained. Not only is it obtained stably over time, but this cushioning thermoplastic resin also exists as a lower layer under the panel section, and since it has an integrated structure as a whole, in terms of strength, The liner has excellent adhesive structure.

Further, in the production of this liner, a melt of a thermoplastic polymer having cushioning properties and elasticity is supplied into the shell of the container lid, and the panel-shaped disc of the oxygen scavenger-containing porous molded article is prepared as described above. When the laminate is positioned on the melt and pressed by a pressing die in the container lid shell, this pressing force causes the panel portion to be bonded to the shell top surface by the melt,
Since the melt is extruded to the outer periphery of the panel portion and molded into the sealing portion, the function-separated liner having the predetermined shape and the predetermined structure described above has an advantage of being produced as a high quality product at a high production speed. is there.

[0022]

Preferred Embodiment of the Invention

Container Lid and Manufacturing Method Thereof In FIG. 1 (side sectional view) showing an example of the container lid according to the present invention, the container lid shell (shell) 1 is a top plate 2 and a skirt portion formed of, for example, metal or hard resin. It consists of three and three. On the inner surface side of the top plate 2, there is provided a thermoplastic polymer liner indicated as a whole by 4. The liner 4 is composed of an upper layer panel portion 5, a sealing portion 6 and a lower layer portion 7.

The upper layer panel portion 5 is made of a deoxidizer-containing porous molded body and is provided inside the sealing portion 6 so as to be exposed inside the container when sealed. The sealing portion 6 is made of a thermoplastic polymer having cushioning properties and elasticity, and is formed so as to project on the outer peripheral side of the panel portion 6 and above the panel portion. In this specific example, the sealing portion 6
Is provided with relatively thick ring-shaped projections 8 and 8 provided on the outer peripheral portion that engage with the bottle mouth, and a ring-shaped groove 9 is formed between the two ring-shaped projections 8 and 8. . The lower layer portion 7 is made of a thermoplastic polymer having cushioning properties and elasticity similarly to the sealing portion 6, and is interposed between the upper layer panel portion 5 and the shell top surface 2 to bond them to each other. It is one. A heat-bonding paint layer (not shown) can be provided on the inner surface of the shell in order to heat-bond the resin forming the lower layer portion 7 to the liner shape and at the same time heat-bonding to the inner surface of the shell.

In FIG. 2 which shows the enlarged internal cross-sectional structure of the porous molded body 5, the porous molded body 5 is composed of the uniformly mixed oxygen scavenger particles 10 and the thermoplastic polymer particles 11. Has been converted. Although the oxygen absorber particles 10 are adhered via the thermoplastic polymer particles 11, the oxygen absorber particles 1
At least a part, preferably a large part, of the surface of No. 1 is exposed without being covered with the polymer. The thermoplastic polymer particles 11 act as a binder for fixing the oxygen absorber particles, but the essence of the particles has not yet been lost, and a spacer for forming voids between the oxygen absorber particles 11, 11. Also plays a role as. In this molded body 5, a large number of communication voids 12 are formed inside,
The surface of the oxygen absorber particles 11 is exposed to the voids 12. From the surface of the porous molded body 5,
Oxygen flows in through the voids 12 described above, and oxygen is absorbed from the surface of the oxygen absorber particles 10.

When the container lid is manufactured, a panel-shaped disc is manufactured in advance from a mixture containing the oxygen absorber particles and the thermoplastic polymer particles. A melt of a thermoplastic composition resin having cushioning properties and elasticity is supplied to the container lid shell, a panel-shaped disc is positioned on the melt, and the laminate is pressed by a pressing die in the container lid shell. Then, the panel portion is joined to the shell top surface with a melt and the melt is extruded to the outer periphery of the panel portion to form a sealed portion.

In FIG. 3 for explaining the steps of the method of the present invention, first, the first step (resin melt supply step)
Then, in the inside of the container lid shell 1, there is a lump 13 of molten resin.
Is supplied after being extruded from the die 15 of the extruder 14 and cut by the rotary cutter 16. Prior to supplying the resin mass 13, the shell 1 can be preheated by means such as high frequency induction heating. It is desirable that the lump 13 be in a state of being temporarily heat-bonded in the shell 1.

Second step (panel disc supplying step)
In the above, the panel-shaped disc 1 of the oxygen absorber-containing porous molded body previously formed on the mass 13 of the resin melt of the shell 1
7 is supplied. In this specific example, a sheet 18 of a porous molded body is supplied between a die cutter 19 and a punch cutter 20 located above the shell 1, and the punch cutter 20 descends to bring the sheet 18 into a predetermined size. Cut into panel discs 17. A disc insertion rod 21 is provided coaxially with the punch cutter 20 so as to be movable up and down.
The cut panel disc is held at the tip and lowered, and the disc 17 is applied to the mass 13 of the resin melt.

In the third step (liner embossing step), the shell 1 including the panel-shaped disc 17 and the resin melt mass 13 is supplied to the pressing operation station, and the shell 1 is supported by the anvil 22. At the same time, the pressing dies 23 and 24 located above the anvil 22 and the sleeve 25 descend downward. The center pressing die 23 has a size corresponding to the panel disc 17, and has a flat or smooth curved surface for forming a thin liner portion, while the circumferential pressing die 24 is It has a peripheral ring-shaped recess 26 for forming a ring-shaped projection of the liner.

First, the sleeve 25 is engaged with the inner peripheral edge of the skirt of the shell 1 to firmly fix the shell 1, and then the pressing dies 23 and 24 are lowered so that the resin mass 13 melted via the panel-shaped disc 17. Start pressing. As a result, the molten resin mass 13 is rapidly spread in the radial direction, and is molded into a liner shape and adhered to the inner surface of the shell.
The liner is held in this pressed state for a certain period of time, and gradually cooled over the whole by a cooling mechanism (not shown) provided in the anvil 22 and the pressing dies 23, 24, and becomes a solidified liner. Sleeve 25 and pressing dies 23, 24
Is raised to obtain a container lid with a press-molded composite liner. The air existing between the pressing die 24 and the shell 1 is discharged to the outside through the gap between the pressing die 24 and the sleeve 25.

Container Lid Shell In the present invention, the material forming the container lid shell is
Metal or plastic or a laminate of these is used. As the metal material, a sheet-shaped or foil-shaped surface-untreated steel (black plate), surface-treated steel, or a light metal such as aluminum is used. As surface-treated steel, chemical treatment such as phosphoric acid treatment and chromic acid treatment on the steel substrate; chemical conversion treatment such as electrolytic chromic acid treatment; electrolytic plating treatment such as electrolytic tin plating, electrolytic zinc plating, electrolytic chrome plating; molten aluminum Plating treatment: Examples include those subjected to hot dipping treatment such as hot tin plating. Its thickness is generally in the range of 0.15 to 0.25 mm.

The surface of these metal materials may be coated with one or more layers of any protective coating known per se and an undercoat coating for heat-bonding a liner. Suitable examples of protective paints are phenol-epoxy paints, epoxy-
Uria paint, epoxy-melamine paint, phenol-epoxy-vinyl paint, epoxy-vinyl paint, vinyl chloride-vinyl acetate copolymer paint, vinyl chloride-vinyl acetate-maleic anhydride copolymer paint, unsaturated polyester paint, saturated One or a combination of two or more such as polyester paint. When the protective coating itself does not have adhesiveness to the thermoplastic resin for the liner used, the coating for thermal bonding of the liner, that is, the known olefin resin thermal bonding, directly on the metal material or through the above-mentioned protective coating. A paint for use, for example, a paint in which polyethylene oxide or an acid-modified olefin resin is dispersed in a film-forming resin can be applied.

These coated metal materials are molded into any container lid shape such as a crown, a pill fur proof cap, a score breaking type easy open cap with a tab, a screw cap, a lug cap and a twist off cap.
used.

On the other hand, as the resin container lid, a resin molded into a cap by means such as injection molding or press molding is used. As the molding resin, a thermoformable resin, for example, medium- or high-density polyethylene, isotactic polypropylene, ethylene-propylene copolymer, polybutene-1, ethylene-butene-1 copolymer,
Olefin resin such as propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ion-crosslinked olefin copolymer (ionomer) or blends thereof; polystyrene, Styrene-butadiene copolymer; ABS resin;
Alternatively, polycarbonate or the like can be used.

Polymer for Forming Sealing Portion As the thermoplastic polymer forming the sealing portion and the lower layer portion, a known thermoplastic polymer which can be melt-extruded and has cushioning properties and elasticity is used, particularly an olefin resin; For example, low-, medium-, and high-density polyethylene, isotactic polypropylene, propylene-ethylene copolymer, polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, propylene-
Butene-1 copolymer, ethylene-propylene-butene-
Blends with olefin resins such as 1 copolymer, ethylene-vinyl acetate copolymer, ion-crosslinked olefin copolymer (ionomer) or blends thereof: ethylene-propylene copolymer rubber, ethylene-propylene-diene Copolymer rubber, hydrogenated ethylene-propylene-
Rubber olefin elastomers such as diene copolymer: S
1 or 2 of BS elastomer, butyl rubber, SBR, etc.
It is possible to use various kinds of various soft plastics and elastomers, which are applied in the form of a melt in the shell and embossed under cooling to obtain a predetermined liner shape. The olefinic resin has good moldability for a liner, is excellent in sealing property, and is also excellent in retaining flavor (flavor) of content beverages.

Thermoplastic polymers particularly advantageous for the purposes of the present invention are low density polyethylene, ethylene copolymers, etc. In terms of inhibiting the liner properties and orientation, low density polyethylene can be added to (a) ethylene. It is desirable to use a composition in which a propylene copolymer and at least one of (b) a thermoplastic elastomer, particularly a styrene-diene (butadiene or isoprene) -styrene block copolymer are blended, and these modifying components are It is preferable to contain it in an amount of 3 to 40% by weight based on the low density polyethylene.

The thermoplastic polymers used in the present invention include compounding agents known per se, for example, white or colored pigments such as titanium white and carbon black; calcium carbonate, white carbon,
Fillers such as clay; antioxidants; lubricants; plasticizers; antistatic agents; heat stabilizers and the like can be blended in a blending ratio known per se.

As another thermoplastic polymer forming the sealed portion, a soft vinyl chloride resin may be mentioned. This soft vinyl chloride resin is melt extruded and press-molded after applying a panel disc, or it is applied in the rotating lid shell in the form of plastisol, and after applying the panel disc, it is heated and gelled. Use as a liner.

The vinyl chloride resin may be a homopolymer of vinyl chloride, or a copolymer of vinyl chloride and a small amount of a comonomer such as vinyl acetate, vinylidene chloride, styrene, acrylic acid ester, methacrylic acid ester and butadiene. Polymers can also be used. The average degree of polymerization of these vinyl chloride-based resins is not particularly limited, and generally 500 to 3000 is convenient. These vinyl chloride resins can be used for the purpose of the present invention, whether they have a relatively fine particle size by an emulsion polymerization method, relatively coarse particles by a suspension polymerization method, or a mixture thereof.

The vinyl chloride resin may of course contain known compounding agents. As the plasticizer, a plasticizer generally used for vinyl chloride resins, for example, DO
Phthalates plasticizers such as P and DOB, DO
A, aliphatic dibasic acid ester plasticizer such as SOA,
One or a combination of two or more of phosphate ester-based plasticizers, hydroxy polycarboxylic acid ester-based plasticizers, fatty acid ester-based plasticizers, polyhydric alcohol ester-based plasticizers, epoxy-based plasticizers, polyester-based plasticizers, etc. Can be used in. As the stabilizer, a metal soap-based stabilizer, an organic tin-based stabilizer, an organic phosphate ester-based stabilizer, as a filler, calcium carbonate, finely divided silica, magnesium carbonate, talc, calcined clay, etc., as a pigment Titanium white,
Carbon black or the like is used, and azodicarbonamide, 4,4-oxybis (benzenesulfonyl) hydrazide or the like is used as the foaming agent, and microcrystalline wax, paraffin wax, polyethylene wax, silicone oil, fatty acid amide is used as the lubricant. System lubricants and the like. Examples of paints having strong adhesion to a vinyl chloride resin liner include vinyl chloride paints and acrylic paints.

Porous Molded Body The porous molded body used in the present invention is produced by intimately mixing the oxygen absorber particles and the thermoplastic polymer particles and compression-molding them. When the molding temperature is higher than the melting point or the softening point for a long time, the thermoplastic polymer particles melt and flow, and the essence of the particles is lost, and a coating of this polymer is formed on the surface of the oxygen absorber particles. Therefore, it is not preferable.

As the oxygen scavenger used in the present invention, all solid oxygen scavengers conventionally used for this kind of application can be used, but generally, those which are reductive and substantially insoluble in water are preferable. Suitable examples thereof include metal powder having a reducing property, such as reducing iron, reducing zinc, reducing tin powder;
Low-grade metal oxides such as ferrous oxide, ferrosoferric oxide, and reducing metal compounds such as iron carbide, silicon iron, iron carbonyl, iron hydroxide; These are alkali metal, alkaline earth metal hydroxides, carbonates, sulfites, thiosulfates, tertiary phosphates, dibasic phosphates, organic acid salts, halides as necessary. Further, it can be used in combination with an auxiliary agent such as activated carbon, activated alumina or activated clay. Further, a polymer compound having a polyhydric phenol in the skeleton, for example, a polyhydric phenol-containing phenol / aldehyde resin and the like can be mentioned. Furthermore, ascorbic acid, erythorbic acid, hydroxycarboxylic acid, or salts thereof may also be mentioned.

These oxygen absorber particles generally have an average of 10 particles.
It is preferable to have a particle size of ˜200 μm, especially 20˜100 μm in order to form a porous molded body and improve the oxygen absorption rate. That is, when the particle size is larger than the above range, the oxygen absorption rate is reduced as a result of the decrease in the surface area, while when the particle size is smaller than the above range,
It is also not preferable because the void volume in the molded body is reduced, or the oxygen absorber particles are more likely to be embedded in the polymer.

On the other hand, the thermoplastic polymer particles include olefin resins; for example, low-, medium-, and high-density polyethylene, isotactic polypropylene, propylene-
Ethylene copolymer, polybutene-1, ethylene-propylene copolymer, polybutene-1, ethylene-butene-1
Copolymer, propylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ion-crosslinked olefin copolymer (ionomer) Or blends thereof: Polyamide resin such as nylon 6, nylon 6,6: polyethylene terephthalate (PET)
Polymer powders such as polyester resin: polycarbonate: vinyl chloride resin:

The thermoplastic polymer particles forming the porous molded body (panel disk) may be the same kind or different kinds as the polymer forming the sealing portion, but there is thermal adhesiveness between them. It is generally preferred to choose such a combination. From this point of view, it is preferable to select polymer particles in which the constituent units of the main polymer are common.

As the thermoplastic polymer particles, any particles can be used as long as they are generally called powder, but there is an optimum particle size in terms of moldability and porosity, and generally 10 to 10 1000 μm, especially 20 to 500
It should have a particle size of μm.

The compounding ratio of the oxygen absorber particles and the thermoplastic polymer particles also has an appropriate range. Generally, it is preferable to use the oxygen absorber particles in an amount of 1 to 99 parts by weight, particularly 10 to 80 parts by weight, based on 100 parts by weight of the thermoplastic polymer particles. When the amount of the oxygen scavenger particles is less than the above range, the oxygen absorption rate and the oxygen absorption capacity are inferior to those within the above range, while when it is more than the above range, the mechanical properties of the porous molded article are increased. Strength and wear resistance tend to decrease.

In the porous molded article used in the present invention, the void content per unit weight is preferably 0.05 to 3 ml / g, particularly 0.1 to 1.5 ml / g. The degree of exposure of the oxygen scavenger particle surface is difficult to measure directly, except for the microscopic observation and the image analysis processing of the result, but the degree of exposure of the oxygen scavenger particle surface is the void content and It turns out that there is a pretty good correlation. When the void content is within the above range, the degree of exposure of the surface of the oxygen absorber particles can be said to be sufficient for the purpose of the present invention. However, if the void content is too large, the mechanical strength of the porous molded article will be reduced.

The void content of the porous molded article depends not only on the particle size of the oxygen scavenger particles and the thermoplastic polymer particles, but also on the pressure and temperature during molding and the molding time. That is, as the pressure increases, the void content decreases, and when the temperature approaches the softening point or melting point, the void content decreases. As the molding temperature, an appropriate temperature is experimentally determined from room temperature to the softening point or lower temperature of the resin. Generally, a suitable pressure is in the range of 5 to 100 kg / cm ² .

The thickness of the porous molded body is generally in the range of 0.1 to 5 mm, particularly 0.2 to 2 mm, and its size is determined according to the size of the liner panel of the container lid.

In the present invention, it is essential that the above-mentioned porous molded article has a large number of voids inside, but even if only the thermoplastic polymer particles in the very surface layer are completely melted. Good. By adopting the melt structure of only the surface layer in this way, it is possible to prevent the migration from the oxygen absorber particles into the content. The melt layer may generally have a thickness of 1 to 100 μm. It is also possible to laminate a thin film that is oxygen-permeable and water-impermeable on the surface of the above-mentioned porous molded article to prevent elution of oxygen absorber particles into the contents. Further, a multilayer structure of a single layer of thermoplastic polymer particles and a blended layer of thermoplastic polymer particles and an oxygen scavenger can be used to prevent elution from the oxygen scavenger particles into the contents.

The amount of the liner-forming thermoplastic polymer to be supplied into the shell of the container lid varies depending on the size of the shell, but can be generally set within the range of 100 mg to 10 g. On the other hand, the panel-shaped disc of the porous body containing the oxygen scavenger particles is preferably in the range of 10 to 90% by weight of the total liner. The present invention will be specifically described by the following examples.

[0052]

【Example】

Example 1 Oxygen absorbent powder containing reducible iron as a main component was added to polypropylene particles in an amount of 40 parts by weight, and the polypropylene particles were mixed with the reducible iron powder in an unmelted state.
It was compressed while being heated to form a porous disk having a diameter of 25 mm. The disc was heat-sealed to the liner panel to form an oxygen-absorbing container lid. The porous molded body of the oxygen-absorbing container lid has a shape-retaining property due to the partial adhesion between polypropylene particles, and at the same time, the reducing iron powder is adhered through the polypropylene particles, but most of it is exposed. Therefore, the oxygen in the container could be deoxidized with almost no reduction in the deoxidizing function of the reducing iron powder.

As a comparative example, polypropylene resin and reducible iron powder were melt-mixed, and then a disc having a diameter of 25 mm was formed, and the disc was heat-sealed to the liner panel to form an oxygen-absorbing container lid. In the performance evaluation, water was filled in a glass bottle having a volume of 1 liter so that the head pace was 80 cc, the product was sealed using the product of the present invention and the comparative product, and the oxygen concentration in the head space was measured with time. The measurement results are shown in Table 1.

[0054]

[Table 1] Thus, the product of the present invention was significantly superior to the comparative product in oxygen absorption performance.

Example 2 To the polyethylene particles, 40 parts by weight of oxygen absorbent powder containing reducible iron as a main component was added, and the polyethylene particles were mixed with the reducing iron powder in an unmelted state, and then at 80 ° C. It was compressed while being heated to form a porous disk having a diameter of 25 mm. The disc was heat-sealed to the liner panel to form an oxygen-absorbing container lid. This oxygen-absorbing container lid is
The oxygen absorption rate was remarkably improved as compared with the oxygen-absorbing container lid having the liner formed by melting and mixing the polyethylene resin and the reducing iron powder.

Example 3 To the polypropylene particles, 40 parts by weight of oxygen absorbent powder containing reducing iron as a main component was added, and the polypropylene particles were mixed with the reducing iron powder in an unmelted state.
When a porous disc having a diameter of 25 mm was formed by compressing while heating with, a porous film was attached to the surface of the mixture and then compressed to form a disc to which the porous films were attached. The disc was heat-sealed to the liner panel to form an oxygen-absorbing container lid. This oxygen-absorbing container lid was able to prevent the reducing iron powder from falling off or eluting without impairing the oxygen-absorbing performance.

As a comparative example, polypropylene resin and oxygen absorbent powder containing reducing iron as a main component were melt-mixed, and a disc having a diameter of 25 mm and a porous film attached thereto was molded to form the disc as a liner panel. An oxygen-absorbing container lid was formed by heat-sealing the part. Table 2 shows the results of evaluation of performance using the invention product and the comparative product in the same manner as in Example 1.

[0058]

[Table 2] Thus, the product of the present invention was significantly superior to the comparative product in oxygen absorption performance.

Example 4 Oxygen absorbent powder containing reducing iron as a main component was added to polypropylene particles in an amount of 40 parts by weight, and the polypropylene particles were mixed with the iron powder in an unmelted state and then heated at 150 ° C. While compressing, the vicinity of the surface was slightly melted.
After cooling, a disk having a diameter of 25 mm was formed of a layer having a porous inside and a resin melted and solidified near the surface. The disc was heat-sealed to the liner panel to form an oxygen-absorbing container lid. As a comparative example, a polypropylene resin and an oxygen absorbent powder containing reducing iron as a main component are melt-mixed, and then a disc having a diameter of 25 mm is formed, and the disc is heat-sealed to a liner panel to form an oxygen-absorbing container lid. Molded. Table 3 shows the results of evaluating the performance of the product of the present invention and the comparative product by the same method as in Example 1.

[0060]

[Table 3] As described above, the product of the present invention was significantly superior to the comparative product in oxygen absorption performance, and at the same time, it was possible to prevent the reducing iron powder powder from falling off or eluting.

Example 5 An oxygen-absorbing container lid was molded by the method of Example 1 using ascorbic acid and a hydroquinone-formalin resin as an oxygen scavenger. As a comparative product, the above oxygen absorber and polypropylene resin were melt-mixed, and then a disc having a diameter of 25 mm was formed, and the disc was fused to the liner panel to form an oxygen-absorbing container lid. The performance evaluation is that the headspace is 80c in a glass bottle with a volume of 1 liter.
It was filled with water so as to be c and sealed using the product of the present invention and the comparative product, and the oxygen concentration in the head space was measured with time. The measurement results are shown in Table 4.

[0062]

[Table 4] Thus, the product of the present invention was significantly superior to the comparative product in oxygen absorption performance.

Example 6 A porous disc was formed from the same material as in Example 1.
Further, after supplying an LDPE-based melt that forms a panel portion and a peripheral sealing portion into the container lid shell, the disc is inserted into the melt and pressed to bond the disc and the sealing material. The melt was squeezed out to the outer periphery of the panel portion to form a sealed portion and an oxygen-absorbing container lid. The oxygen-absorbing container lid was pressed by the mold, and even though the surface area was further reduced, the oxygen-absorbing performance was excellent, the adhesive force between the sealing material and the disk was excellent, and the openability was excellent.

[0064]

According to the present invention, in a container lid comprising a container lid shell and a polymer liner provided on the inner surface side of the shell, an oxygen scavenger particle and a thermoplastic resin are added to the liner. A polymer molded particle is contained, and the oxygen absorber particles are fixed via the thermoplastic polymer particles, but at least a part of the surface of the oxygen absorber particles is exposed to form a layer of a porous molded body. As a result, oxygen flows from the surface of the porous molded body through the voids, and oxygen is absorbed from the surface of the oxygen absorber particles. Alternatively, oxygen remaining in the contents can be absorbed and removed.

Further, since the oxygen scavenger particles are solidified and integrated into one piece by the thermoplastic polymer particles, not only is it easy to handle as an integrated molded article, but also
There is no problem that the oxygen absorber particles are released in the form of powder and adhere to the member of the container lid or are mixed in the contents.

In the present invention, if the porous molded article containing the oxygen scavenger particles and the cushioning thermoplastic polymer constituting the liner are provided independently of each other, mutual influences are prevented and the oxygen generated by the oxygen scavenger particles is prevented. The absorbing effect and the sealing effect as the liner are mutually best achieved.

As described above, according to the present invention, the residual oxygen in the container can be quickly removed, whereby the deterioration of the contents and the deterioration of the flavor can be prevented, and the structure of the container lid is simple and the manufacture is easy. In addition, the high oxygen-absorbing container lid can be manufactured with excellent productivity and high quality.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of a container lid according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing an enlarged inner cross-sectional structure of a porous molded body used in the present invention.

FIG. 3 is a process chart for explaining the steps of the method of the present invention, wherein A is the first step (resin melt supply step),

[Explanation of symbols]

1 is a container lid shell (shell), 2 is a top plate, 3 is a skirt portion, 4 is a thermoplastic polymer liner, 5 is a porous molded body (upper layer panel portion), 6 is a sealing portion, 7 is a lower layer portion, 8 is a relatively thick ring-shaped projection, 9 is a ring-shaped groove, 10 is an oxygen absorber particle, 11 is a thermoplastic polymer particle, 12 is a void, 1
3 is a lump of molten resin, 14 is an extruder, 15 is a die, 16 is a rotary cutter, 17 is a disc-shaped disc, 18
Is a sheet of a porous molded body, 19 is a die cutter, 20 is a punch cutter, 21 is a disc insertion rod, 22 is an anvil, 23 and 24 are pressing dies, 25 is a sleeve, and 26 is a peripheral ring-shaped recess.

Claims (8)

[Claims] 1. A container lid comprising a container lid shell and a polymer liner provided on the inner surface side of the shell, wherein the liner contains deoxidizer particles and thermoplastic polymer particles. , The oxygen absorber particles are fixed via the thermoplastic polymer particles, at least a portion of the surface of the oxygen absorber particles is exposed is provided with a layer of a porous molded body, Oxygen absorbing container lid. 2. The porous molded body is provided as an upper layer portion that constitutes a panel portion inside the sealing portion, and a thermoplastic polymer having cushioning properties and elasticity is provided on the upper layer portion and the shell top surface. It is provided as a lower layer portion which is interposed between the two and is joined to each other, and as a sealing portion which is formed integrally with the lower layer portion on the outer peripheral side of the panel portion and above the panel portion. The oxygen-absorbing container lid according to claim 1. 3. The composition of the thermoplastic polymer particles is a polyolefin resin or an acid-modified polyolefin resin, or a polyolefin resin or an acid-modified polyolefin resin, and a hygroscopic resin or a hygroscopic resin. The oxygen-absorbing container lid according to claim 1, which is a resin composition containing a certain inorganic substance. 4. The oxygen absorbing container lid according to claim 1, wherein the oxygen scavenger is reduced iron or reducing iron to which an oxygen absorption reaction accelerating aid such as an alkali metal is added. 5. The oxygen-absorbing container lid according to claim 1, wherein at least one surface of the layers of the porous molded body is covered with a thermoplastic resin film or a porous film. 6. The oxygen-absorbing container lid according to claim 1, wherein a layer in which the thermoplastic resin polymer particles are melted and solidified is present near the surface of the layer of the porous molded body. 7. A container lid shell is supplied with a melt of a thermoplastic polymer having cushioning properties and elasticity, and contains oxygen scavenger particles and thermoplastic polymer particles, wherein the oxygen scavenger particles are heated. The panel-shaped disc of the porous molded body, which is fixed through the plastic polymer particles, but at least a part of the surface of the oxygen absorber particles is exposed, is placed on the melt, and this laminated body is placed in a container. Oxygen absorbency characterized by pressing with a pressing die in the lid shell to bond the panel part to the top surface of the shell with a melt and extruding the melt to the outer periphery of the panel part to form a sealed part Method of manufacturing container lid. 8. A sheet of the porous molded body is supplied onto the container lid shell to which the melt of the polymer is supplied, and the sheet is cut into panel-shaped discs, and the cut discs are positioned. 8. The method for producing an oxygen-absorbing container lid according to claim 7, wherein the resin melt of the shell is applied in the state of being kept.