JP2000238812A - Lid member with retort adaptability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lid member having adaptability to printing, high barrier property, sealability, unsealability and a retort adaptability of high rate of conversion into paper. SOLUTION: This lid member is composed of a dropping lid 24 comprising a top plate 23, a peripheral wall 22 vertically arranged at a peripheral edge of the top plate such that it can be in close contact with an inner wall of a barrel section 11 of a cylindrical container, and a seal flange 21 arranged at an upper edge of the peripheral wall outwardly in parallel with the top plate, and a lid material sheet section 25 to cover the entire dropping lid and having a folded portion 28 with the peripheral edge being folded inside to cause the lid material sheet section to cover the dropping lid material section 24 so as to form a space 26 between the sheet section and the top plate, and then the folded portion 28 of the lid material sheet section and the seal flange 21 at the dropping lid material section are heat welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a lid material having a paper conversion rate of 60% or more that can withstand a retort sterilization treatment for one minute.

[0002]

2. Description of the Related Art As a lid material for a retort container for food use, a lid material having a simple structure in which a plastic film is laminated and not molded is mainly used. In this case, since the head space is small, there are serious problems such as poor sealing due to impurities at the time of filling the contents and spillage of the contents at the time of opening. On the other hand, in the case of a molded dropping lid, since it is necessary to use a material having moldability, printability is not so good at present.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems relating to a dropping lid type lid material for a food retort container, and has printability and high barrier properties. With excellent sealing and opening properties,
It is an object of the present invention to provide a cover material having a high degree of paper formation and having retort suitability.

[0004]

The lid material having suitability for retort according to the present invention is a lid material for sealing an opening of a cylindrical container having an outwardly protruding rim at the periphery of the opening. The lid is a top plate, a peripheral wall erected on the periphery of the top plate so as to be able to adhere to the inner wall of the body of the cylindrical container, and a seal provided on the upper edge of the peripheral wall outward and parallel to the top plate. Flange, a dropping lid material portion consisting of, and a lid material sheet portion having a folded portion whose peripheral edge is folded inward, covering the entire dropping lid material portion,
The lid material sheet portion is formed such that a space is formed between the lid material sheet portion and the top plate, with the edge of the folded portion being inside, and the folded portion of the lid material sheet portion and the dropped lid are formed. It is characterized in that the material portion and the seal flange are heat-sealed.

[0005] The lid sheet is characterized in that it is a laminated sheet comprising at least four layers of polypropylene (PP) film, paperboard, barrier film, and PP film laminated in this order from the outside.

Further, the PP film used for the inner and outer surfaces of the cover sheet portion is a film obtained by forming a PP resin having a melting point of 150 ° C. or more.

Further, the barrier film constituting the cover sheet portion is any one of a film formed with an inorganic compound vapor deposited thin film, a film formed with a metal compound vapor deposited thin film, and a barrier plastic film. I have.

[0008] Further, the drop-in lid member is obtained by injection molding a PP resin having a melting point of 150 ° C or more.

[0009]

As described above, the cover material having retort suitability according to the present invention comprises a top plate, a peripheral wall erected on the periphery of the top plate so as to be able to adhere to the inner wall of the body of the cylindrical container, and an upper edge of the peripheral wall. A sealing flange provided in parallel with the top plate toward the outside, a dropping lid material portion, and a lid material sheet portion having a folded portion whose peripheral edge is folded inward, covering the entire dropping lid material portion, The lid material sheet portion is formed such that a space is formed between the lid material sheet portion and the top plate, with the edge of the folded portion being inside, and the folded portion of the lid material sheet portion and the dropped lid are formed. Since the seal flange of the material portion is thermally fused, the end surface of the cover material sheet portion is not exposed to the outside, and water does not enter the inside of the cover material sheet portion from the end surface even if retort processing is performed. .

[0010] The outermost PP film of the lid sheet portion is
Use a film obtained by forming a PP resin with a melting point of 150 ° C or higher, and use a dropping cover material obtained by injection molding a PP resin with a melting point of 150 ° C or higher. It has retort suitability.

[0011] In addition, since the paperboard is used in the layer structure in the lid material sheet portion, it is possible to perform beautiful printing.

Further, since a barrier film is used in the layer structure of the cover sheet portion, the gas barrier property is excellent.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments. The cover material having retort suitability according to the present invention is, for example, as shown in FIGS.
A dropping lid member portion 24 comprising a sealing flange 21 provided on the upper edge of the peripheral wall outwardly in parallel with the top plate;
And a cover material sheet portion 25 having a folded portion 28 whose peripheral edge is folded inward, which covers the entire dropped cover material portion.

The cover material sheet portion 25 is composed of a laminated sheet having at least a four-layer structure in which a PP film, a paperboard, a barrier film, and a PP film are laminated in this order from the outside of the container.

PP used for the inner and outer layers of the cover sheet section 25
The PP resin constituting the film is a PP resin based material having a melting point of 1
When the temperature is 50 ° C. or higher, any type of resin, such as a random type, a block type, or a homo type, can be used because the heat resistance during the retort sterilization treatment is cleared.

The periphery of the cover sheet portion is folded back so that the end surface is not exposed to the outside, and is crushed to form a folded portion 28.

The barrier film constituting the cover sheet portion 25 includes a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film,
A vapor-deposited film obtained by vapor-depositing a thin film of silicon oxide, aluminum oxide or the like on a substrate film such as a biaxially stretched nylon (ONy) film by a vacuum vapor deposition method of about 400 ° can be preferably used. A film coated with (PVDC) resin may be used.

The paperboard constituting the cover sheet portion 25 is the base material of the base sheet portion, and a cup base paper having a basis weight of about 100 to 320 g / m ² , ivory, double-sided card, or the like can be preferably used to impart printability. Diatomaceous earth 10-18
g / m ² is preferable.

The lamination of each film is preferably performed by a known dry lamination method using, for example, a two-component reactive polyester adhesive.

The drop-in lid member 24 is formed by injection molding a PP resin. The PP resin system uses P
As with the P film, if the melting point is 150 ° C. or more, any type of resin such as random type, block type, and homo type can be used because it clears the heat resistance during the retort sterilization treatment.

Finally, the lid sheet 25 is dropped so that a space 26 is formed between the folded sheet and the top plate 23 with the edge 27 of the folded portion inward. Is heat-sealed by an ultrasonic sealing method or a hot air sealing method to form a lid member 20 having retort suitability according to the present invention. When the laminated sheet for the cover sheet section is folded while being rotated, wrinkles and the like are generated in the folded section 28,
At the time of fusion, drop into the step
The resin melts and fills, playing a vital role.

As shown in FIG. 1, the folded portion of the lid material sheet portion and the sealing flange of the dropped lid material portion were slightly extended outward from the folded portion, and the seal flange was slightly retracted inward. When heat sealing is performed in this state, the lid can be easily opened.

[0023]

EXAMPLES Examples of the present invention will be described below more specifically. <Example 1> First, the melting point was 151 ° C and the density was 0.91.
g / cm ³ of a PP resin composed of an ethylene-propylene random block copolymer, and having a thickness of 0.5 m
Thus, a drop-off lid member 24 of m was prepared.

At this time, the diameter of the cylindrical container described below: 58.
7mm, internal height: 85.6mm, content: 200ml
In consideration of (distilled water), the height difference between the sealing flange 21 of the drop-down lid member and the top plate 23 was set to 8 mm so that the head space was 10 mm.

Next, a laminated sheet constituting the lid material sheet portion 25 was produced by a dry lamination method using a polyester resin-based two-component reactive adhesive with the following configuration.

[Outside of Container] CPP film (ethylene-
Propylene block copolymer type, melting point: 160 °
C, 30 μm thickness) / coated paperboard (160 g / m ² ): paperboard type; ivory, diatomaceous earth coating amount; 15 g / m ²
/ PET film (12 μm thick), silicon oxide evaporated thin film (400 °) / CPP film (ethylene-propylene block copolymer type, melting point: 160 ° C., 30 μm
Thickness) [Inside of container]

After the laminated sheet was punched into a predetermined size, the periphery was folded while rotating the sheet to produce a lid sheet section 25 having a folded section 28.

Finally, with the edge 27 of the folded portion 28 inside, the lid material sheet portion 25 is placed between the top plate 23 and the space portion 26.
Is formed, and the folded back portion 28 of the written sheet portion and the seal flange 21 of the dropped cover material portion are heat-sealed by an ultrasonic sealing method to form a cover having retort suitability of the present invention. Material 20 was produced.

Separately, a cup-shaped paper container having the following configuration was manufactured as a cylindrical container suitable for the lid material.

First, a laminated sheet constituting the container body and a tape-shaped laminated film for covering the exposed end face of the container body obtained by molding the laminated sheet were dried using a polyester resin-based two-component reactive adhesive. It was produced by the lamination method in the following configuration.

Layer structure of laminated sheet, [outside container] CPP
Film (50 μm thickness) / PET film (9 μm thickness)
/ Coat layer (coating amount: 15 g / m ² ) / cup base paper (basis weight: 295 g / m ² ) / PET film 12 μm thick),
Silicon oxide deposited thin film (400Å) / CPP film (50
μm thickness) [inside of container]

Layer structure of tape-shaped laminated film, CPP film (30 μm thickness) / PET film 12 μm thickness),
Silicon oxide evaporated thin film (400Å) / CPP film (30
μm thickness)

The CPP film used for the laminated sheet and the tape-shaped laminated film is a CP having the following constitution and physical properties.
This is a P film formed of the same type of PP resin as the PP resin used for the cover sheet portion. That is, a propylene-ethylene block copolymer, melting point: 160 ° C,
・ Density: 0.90 g / cm ³・ MFR: 8 g / 10 m
in. -Ethylene content: 2.5 wt%-Ethylene-butene copolymer (amorphous resin) is added to impart impact resistance.

The moisture content of the cup base paper is 5.0%.

To form a cup-shaped container from the laminated sheet, a body member blank serving as a body 11 of the container and a bottom 1
3 was produced. Then, the tape-shaped laminated film 14 having a width of 10 mm was impulse-sealed over all exposed portions on both end surfaces to be bonded portions when the trunk member blank was formed, thereby covering the exposed portions on the paper end surface.

A cylindrical member having an edge portion 12 curled outward by a generally used paper cup molding machine using a body member blank in which the exposed portion of the paper end surface is covered with a tape-shaped laminated film and a bottom member roll. Cup-shaped paper container 10 was molded. As a heating method, a method of locally heating and pressing the CPP film on the outside of the welded portion was adopted in order to prevent the generation of blisters due to vaporization of moisture in the cup base paper of the laminated sheet. The dimensions of the cup-shaped paper container are as follows:
8.7 mm, cup internal height: 85.6 mm.

After the cup-shaped paper container is formed, the edge is heated and pressed from above and below to flatten and crush it.

A hot melt PP resin is injected into the inner wall portion of the bottom of the produced paper container to inject the bottom incurred annular member 15 and the lip portion is heated by the lip peripheral member 16 covering the outer surface and the lower surface. A paper container covered with the melted PP resin and capable of being subjected to retort sterilization treatment without any exposure of the paper end surface was produced (see FIG. 3). The container was coated with the PP resin by an insert injection molding method in which the hot-melted PP resin was injected into a mold in which the container was previously inserted and arranged.

The PP resin used at this time had the following composition and physical properties. That is, ethylene-propylene block copolymer, melting point: 160 ° C., density:
0.90 g / cm ³ , MFR: 14 g / 10 min.

The above-prepared paper container was filled with 200 ml of distilled water at 65 ° C., and the opening was covered with the same lid material.
The folded portion of the lid and the seal flange were heat-sealed by an ultrasonic sealing method to seal the paper container, thereby obtaining Example 1 (see FIG. 2).

<Comparative Example 1> Except for using the lid material of Example 1 from which the drop-in lid material portion was removed,
The structure is the same as that of the first embodiment.
This was filled with 0 ml and sealed to obtain Comparative Example 1 (detailed description is omitted. There is no dropping lid portion as compared with Example 1).

With respect to the two types of paper containers thus produced, Example 1 and Comparative Example 1, the container deformation after hot filling, the suitability for retort, and the suitability for microwave oven were tested and evaluated according to the methods described below.

<Experiment 1> Deformation of Container after Hot Filling Example 1 and Comparative Example 1 in which the temperature of the distilled water to be filled was sealed at 65 ° C. and two kinds of containers were allowed to cool to room temperature (23 ° C.). Of the container body was visually observed. Table 1 shows the results. In Table 1, ○ indicates that there was no shape change such as deformation in the container body, and × indicates that the container body was dented and deformed.

<Experiment 2> Suitability of retort (1) Two kinds of containers of Example 1, Comparative Example 1 and Comparative Example 1 filled with 200 ml of distilled water at normal temperature were used under the following two conditions by using a device manufactured by HISAKA MFG. Perform the retort sterilization process of the aeration method,
The presence or absence of deformation of the container after the retort sterilization was visually observed. Table 2 shows the results. In Table 2, ○ indicates that there was no change in shape such as deformation in both the container body and the lid, and × indicates that the lid was dented and deformed. Condition 1 ‥‥ Initial temperature; 80 ° C., temperature rising condition; 120 ° C., reaching 15 minutes Holding condition: 30 minutes, cooling time; 30 minutes Condition 2 ‥‥ Initial temperature; 80 ° C., temperature rising condition; 130 ° C, reaching 15 minutes Holding condition: 30 minutes, cooling time: 30 minutes

<Experiment 3> Suitability for retort (2) Example 1, Comparative Example 1, Two kinds of containers were filled with 200 m of distilled water.
Instead of l, the following oxygen barrier detecting material was filled as a content, and a retort sterilization treatment was performed under the above two conditions, and the presence or absence of oxygen barrier properties was visually observed. Table 2 shows the results. Oxygen barrier detection material ‥‥ A mixture of sucrose fatty acid ester, agar powder, sodium hydroxide, methylene blue, and D-glucose dissolved in hot water. Evaluation method of barrier properties 性 の Methylene blue develops a blue color when exposed to oxygen In Table 2, ○ indicates that the content liquid does not develop blue and has oxygen barrier properties, and × indicates that the entire content liquid develops blue and oxygen Indicates that the barrier properties have deteriorated.

<Experiment 4> Suitability of microwave oven The two kinds of containers after the retort sterilization treatment used in Experiment 2 were set in a generally used microwave oven having a rated voltage of 100 V and a rated frequency of 60 Hz under the following conditions. The suitability for microwave oven was visually observed and evaluated. Table 3 shows the results.
Shown in Microwave oven heating conditions ‥‥ Heating time 3 minutes In Table 3, ○ indicates a state where reheating with a microwave oven was successfully performed, and X indicates a state where reheating with a microwave oven was not successfully performed.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

Considering from Tables 1, 2 and 3, a container using a lid member provided with a drop-in lid member portion in which the height difference between the seal flange and the top plate is set to 8 mm so that the head space is 10 cc is as follows. It can be seen that hot filling is possible, the gas barrier property is excellent, and in addition to the retort sterilization suitability, it also has a microwave oven suitability after retort sterilization (Example 1).

[0051]

As described above, the cover material having retort suitability according to the present invention can be printed on a paperboard portion, so that the printability of the cover material is improved. Up, drop-down type lid material reduces the head space, prevents deformation of the container during hot filling, prevents contaminant sealing, prevents contents from spilling when opening the container, space Can be filled with a drug such as a deoxidizer, and the lid can be provided with a deoxidizing function.Furthermore, by filling the space with an inert gas such as nitrogen gas, the oxygen concentration in the container can be reduced. It is possible and has effects such as prevention of oxidation of the contents.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a cross section of an embodiment of a lid member of the present invention.

FIG. 2 is an explanatory cross-sectional view showing a state where the lid member of the present invention is placed on a cylindrical container and hermetically sealed.

FIG. 3 is an explanatory sectional view of a cylindrical container (cup-shaped paper container) used in Example 1.

[Description of Signs] 10 ‥‥ cylindrical container, cup-shaped paper container 11 ‥‥ trunk 12 ‥‥ flange 13 ‥‥ bottom 14 ‥‥ tape-like laminated film 15 ‥‥ bottom incurred annular member 16 ‥‥ edge periphery Member 20 lid material 21 seal flange 22 peripheral wall 23 top plate 24 drop-down lid material portion 25 lid material sheet portion 26 space portion 27 edge edge 28 folded portion

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) B65D 51/24 B65D 51/24 DF term (reference) 3E084 AA02 AA12 AA24 AA34 AA37 AB10 BA02 CA01 CC01 CC02 CC03 CC05 CC07 CC08 DA01 DC01 DC02 DC03 DC05 DC07 DC08 EA03 EC05 FA09 FD13 GA08 GB08 GB12 4B021 LA15 LA25 LA26 LP01 LP07 4C058 AA21 BB02 EE14 EE16 EE24 4F100 AA00C AK01C AK07A AK07D BA04 BA07 BA10A BA10D01

Claims (5)

[Claims] 1. A lid material for sealing an opening of a cylindrical container having an outwardly protruding rim on the periphery of the opening, the lid material comprising a top plate and a body inner wall of the cylindrical container. A drop-in lid material portion, comprising a peripheral wall erected on the peripheral edge of the top plate so as to be able to adhere to the top plate, and a seal flange provided on the upper edge of the peripheral wall outwardly in parallel with the top plate; A cover material sheet portion having a folded portion whose peripheral edge is folded inward, covering the whole,
The cover material sheet portion is formed such that a space portion is formed between the cover material sheet portion and the cover material portion with the edge of the folded portion inside, and the folded portion of the cover material sheet portion and the dropped cover are formed. A cover material having retort suitability, wherein the cover member is heat-sealed to a seal flange of a material portion. 2. The cover material sheet portion is formed of a polypropylene (PP) film, a paperboard, a barrier film,
The retort-suitable lid material according to claim 1, which is a laminated sheet composed of at least four layers laminated in the order of P films. 3. A PP used on the inner and outer surfaces of the cover sheet portion.
2. The film according to claim 1, wherein the film is obtained by forming a PP resin having a melting point of 150 ° C. or higher.
Or a cover material having retort suitability according to 2. 4. A method according to claim 1, wherein the barrier film constituting the cover sheet portion is any one of a film formed with an inorganic compound vapor-deposited thin film, a film formed with a metal compound vapor-deposited thin film, and a barrier plastic film. 4. A lid material having retort suitability according to claim 1, 2 or 3. 5. A melting point of the drop-in lid member is 150 °.
5. The cover material having retort suitability according to claim 1, wherein the cover material is obtained by injection-molding a PP resin of C or more.