JPH11292156A - Lid for paper container subjectable to retort sterilization treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lid applicable to a paper container subjectable to retort sterilization treatment. SOLUTION: The lid comprises a fall lid part 24, a lid sheet part, and an end-face- covering member 30. The lid part 24 comprises a top plate 23, a peripheral wall 22 erected on the peripheral edge of the top plate, which can closely contact the internal wall of the body 11 of a cup-shaped paper container, and a seal flange 21 formed outward on the upper edge of the peripheral wall so as to be parallel with the top plate. The lid sheet part covers the entire fall lid part, makes an empty space 26 between the top plate and itself, and is heat-fused to the seal flange. The end-face- covering member 30 covers the heat-fused part of the fall lid part and lid sheet part approximately half the depth inward from their end edges so as to fit the external face and end face of the fall lid part and the external face and end face of the lid sheet part into it, and is placed on the mouth edge of the cup-shaped container so that it can be heat-fused. The end-face-covering member is provided by an insert injection molding method in which a heat-melted PP resin is injected and molded in a mold where the fall lid part and lid sheet part fused together are inserted and disposed in advance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover material for a paper container which can withstand reduced pressure in a container after hot filling and which can be subjected to a retort sterilization process, and more particularly to a retort sterilization process which can be reheated by a microwave oven. The present invention relates to a lid material used for a paper container having a cup shape.

[0002]

2. Description of the Related Art Paper containers which can be subjected to a retort sterilization treatment are disclosed, for example, in JP-A-57-46734 and JP-A-5-46734.
Many inventions and ideas have been disclosed, including the inventions disclosed in JP-A-8-52033 and JP-A-58-20638.

[0003] The invention disclosed in Japanese Patent Application Laid-Open No. 57-46734 discloses a synthetic resin or paper mainly composed of a thermoplastic resin excluding a high-density polyethylene resin and having a melting point of 115 ° C or higher as both outer layers. The both ends of the laminated sheet made of aluminum foil are rolled and subjected to waterproofing and welded to form a cylindrical body, and the upper and lower openings of the obtained cylindrical body are formed with the synthetic resin in the laminated sheet. A container closed with a lid made of aluminum foil whose inner surface is coated with the same kind of synthetic resin, wherein the laminated sheet is a packaging container having a laminated structure in which aluminum foil is disposed on both sides of paper. Things.

Further, the invention disclosed in Japanese Patent Application Laid-Open No. 58-52033 discloses a method in which both ends corresponding to a body seal portion of a fan-shaped or rectangular blank sheet made of a paper material subjected to a water-resistant treatment on both sides are opposite to each other over a certain width. The upper and lower parts of the body cylinder formed by folding both sides of the blank sheet so as to form a cylinder and bonding both ends at the surface having the pair of folded pieces obtained above, This is a completely water-resistant paper container sealed with a lid and a bottom plate so that the paper end surface is not exposed.

Further, in the invention disclosed in Japanese Patent Application Laid-Open No. 58-20638, the resin layer forming the inner layer and the intermediate layer made of paperboard and the like are integrally bonded, and the resin layer forming the outer layer and the intermediate layer are integrally bonded. Alternatively, the resin is bonded to each other at the upper edge of the container, the layers are degassed, and a multilayer container is formed in which an intermediate layer is sandwiched between resin layers on both sides.

[0006] However, these inventions are not suitable for microwave ovens because they all use aluminum foil, and there is still a problem in disposability because they use a lot of synthetic resins.
And so on.

[0007]

Accordingly, the present inventors have developed a retort sterilizable paper container which does not use aluminum foil and has a small amount of synthetic resin and which is suitable for a microwave oven. No. and others. An object of the present invention is to provide a lid material to be applied to these paper containers that can be subjected to a retort sterilization treatment.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, the opening edge is curled outward, and the upper and lower layers are flatly thermocompression-bonded to each other. A lid material for sealing an opening of a retort-sterilizable cup-shaped paper container having a portion, wherein the lid material is provided on a top plate and a body inner wall of a cup-shaped paper container erected on the periphery of the top plate. A drop-in lid material portion comprising a peripheral wall that can be in close contact and a seal flange provided on the upper edge of the peripheral wall outwardly in parallel with the top plate, and between the top plate and the entirety of the drop-in lid material portion. And a cover material sheet heat-sealed with the seal flange, and a substantially half-depth inward from the edge of the heat-sealed portion of the drop-in cover material portion and the cover material sheet portion. Now, the outer surface and the end surface of the dropping lid material portion and the outer surface and the end surface of the lid material sheet portion are fitted. And a heat-fused end face covering member mounted on the rim of the cup-shaped paper container, wherein the heat-sealed drop-down lid member and the lid material A retort-sterilizable paper container lid material provided by an insert injection molding method for injecting hot-melt polypropylene resin into a mold in which a sheet portion is inserted and arranged in advance.

According to the second aspect of the present invention, an opening handle portion is formed on a peripheral edge of the end face covering member so as to partially protrude outward from the edge when the cover material is placed over the opening of the paper container. A cover material for a paper container that can be subjected to a retort sterilization treatment.

According to the third aspect of the present invention, the cover sheet portion has at least a four-layer structure in which a polypropylene (PP) film, a paperboard, a barrier film, and a PP film are laminated in this order from the outside of the container. It is a lid material for a paper container which can be subjected to a retort sterilization treatment, which is a laminated sheet.

In particular, the PP film used for the inner and outer surfaces of the above-mentioned cover sheet has a melting point of 150 ° C. or more.
It is obtained by forming a P resin into a film.

Further, in the invention according to claim 5, the barrier film constituting the cover sheet portion is a film on which an inorganic compound vapor-deposited thin film is formed, a film on which a metal compound vapor-deposited thin film is formed, or a barrier plastic film. Is one of

In the invention according to claim 6, the paperboard constituting the cover sheet portion is a paperboard having a diatomaceous earth coat layer applied to the paperboard surface in an amount of 10 to 18 g / m ² .

Further, in the invention according to claim 7, the drop-in lid member portion is made of a single-layer or two or more-layer thermoplastic resin film using PP resin at least on a joint surface with the lid member sheet portion, Further, the melting points of all the thermoplastic resin films used are 140 ° C. or higher.

Further, in the invention according to claim 8, the PP resin used for the insert injection molding method, wherein the PP resin used for the end face covering member is a PP resin and an LDPE resin or a PP resin and an ethylene-butene copolymer. It is a resin blended with a polymer resin.

In particular, the blend ratio of the PP resin and the LDPE resin or the PP resin and the ethylene-butene copolymer resin is 100/10 to 100/30, respectively.
It is.

[0017]

As described above, according to the present invention, the lid is provided on the top plate, the peripheral wall which can be in close contact with the inner wall of the body of the cup-shaped paper container erected on the peripheral edge of the top plate, and the upper edge of the peripheral wall. A sealing lid portion provided outwardly in parallel with the top plate, a dropping lid material portion, and a cover portion that covers the entire dropping lid material portion, forms a space between the top plate, and a sealing flange. And the heat-sealed lid material sheet, and the outer surface and the end surface of the dropped lid material portion at a depth approximately half inward from the edge at the heat-sealed portion of the dropped lid material portion and the lid material sheet portion. And the outer surface and the end surface of the lid material film portion are covered so as to be fitted, and an end surface covering member that is placed so as to be heat-fusible to the rim portion of the cup-shaped paper container, Even after cooling after hot filling, the reduced pressure in the container can be absorbed in the space, and the deformation of the container body can be prevented.

[0018] Further, when the lid material is placed over the opening of the paper container at the peripheral edge of the end surface covering member, an opening handle portion which is partially protruded outward from the edge of the paper container is formed. At the time of opening, the opening can be easily opened from the opening handle portion.

Further, the PP resin used for the end face covering member is a blend resin of PP resin and LDPE resin or PP resin and ethylene-butene copolymer resin. It is a film made of a PP resin having a melting point of at least ° C, and the film used on the outer side of the container of the lid sheet portion is a film obtained by forming a PP-based resin having a melting point of at least 150 ° C. At the time of opening, the lid material peels from the container body with an appropriate peel strength.

Further, since the barrier film constituting the cover sheet portion is formed of 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, It has good protection of the contents and is suitable for microwave ovens.

Further, the PP film used on the outside of the container of the cover sheet portion is a polypropylene resin having a melting point of 150 ° C. or higher, and the melting point of the dropping cover portion is 1 point.
40 ° C. or higher PP resin, and the end face covering member is made of PP resin.
Since a resin blended with a resin and an LDPE resin or a PP resin and an ethylene-butene copolymer resin is used, it is suitable for a retort sterilization treatment.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. As shown in FIGS. 1 (a), 1 (b) and 2, the lid material for a paper container which can be subjected to the retort sterilization treatment of the present invention is, for example, a top plate 23 and a cup-shaped upright provided on the periphery of the top plate. A drop lid member 24 comprising a peripheral wall 22 which can be in close contact with the inner wall of the body 11 of the paper container, and a seal flange 21 provided on the upper edge of the peripheral wall outwardly in parallel with the top plate; Cover the entire part, and the space 26 between the top plate
And a cover material sheet portion 25 thermally fused to the seal flange 21, and a depth approximately half inward from the edge at the heat-sealed portion of the dropped cover material portion and the cover material sheet portion. so,
An end surface covering member which covers the outer surface and the end surface of the dropping lid member portion and the outer surface and the end surface of the lid material film portion so as to be fitted, and is mounted on the lip portion 12 of the cup-shaped paper container so as to be heat-fusible. 30.

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.

The PP resin constituting the PP film used for the inner and outer layers of the cover material sheet portion 25 may be any of a random type, a block type and a homo type if the melting point is 150 ° C. or higher. Even resins can be used because they clear heat resistance during retort sterilization.

The barrier film constituting the cover sheet portion 25 is 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 section 25 is a base material of the cover sheet section, and 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. 10-1 diatomaceous earth layer
What provided about 8 g / m < ² > is good.

A nylon film may be interposed in the film constituting the cover material sheet portion 25 for the purpose of reducing impact.

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

The drop-in lid member 24 is made of a thermoplastic film having a single-layer structure or a two-layer structure or more using PP resin at least on the joint surface with the lid member sheet portion 25.
It is a necessary condition that the melting point of all the resins used is 140 ° C. or higher in order to clear the heat resistance during the retort sterilization treatment.

A barrier resin layer may be provided in the layer structure of the drop-in lid member 24, and may be formed of ethylene vinyl alcohol copolymer resin (EVOH), vinylidene chloride resin (PV
DC) etc. can be illustrated as a suitable resin.

It is desirable that the total thickness of the thermoplastic resin film forming the drop lid portion 24 is 150 μm or more, and is produced by a pressure forming method or a vacuum forming method.

The squeezing amount (level difference) of the dropping cover member portion 24 depends on the diameter of the paper container and the filling capacity of the contents.
The height difference between the seal flange 21 and the top plate 23 is designed so that the head space of the space 26 is 10 cc or less.

The end surface covering member 30 is provided with
The sealing flange 21 and the lid material sheet portion 25 are heat-sealed by an ultrasonic sealing method or a heat sealing method to form a heat-sealed portion 21a. The inside is covered to about half of the heat-sealed portion 21a, and is mounted on the rim 12 of the cup-shaped paper container so as to be heat-sealed.

For covering the heat-sealed portion 21a of the end face covering member 30, the heat-sealed drop-in lid member 24 and the lid sheet portion 25 are heat-melted in a mold previously inserted and arranged. This is performed by an insert injection molding method for injecting a PP resin.

As the PP resin used for the end face covering member 30, a resin in which a PP resin and an LDPE resin or a resin in which a PP resin and an ethylene-butene copolymer resin are blended can be preferably used.
The range of 0/10 to 100/30 is preferred. By defining the blend ratio in the range of 100/10 to 100/30, cohesive failure occurs at the interface between the end face covering member and the rim,
An easy peeling phenomenon generally called easy peeling occurs.

When a cover material is placed over the opening of the paper container around the edge of the end surface covering member 30, an opening handle portion 29 that partially projects outward from the rim is provided to open the paper container. When
Opening is easier.

[0037]

EXAMPLES Examples of the present invention will be described below more specifically. <Example 1> First, a PP single-layer sheet having a thickness of 200 µm was prepared as a thermoplastic resin film constituting the drop-in lid member 24.

The PP resin used was an ethylene-propylene random block copolymer having a melting point of 151 ° C.
-A resin having physical properties of a density of 0.91 g / cm ² was used. Then, the obtained single-layer sheet was vacuum-molded to form a dropping lid member 24.

The squeezing amount (level difference) of the vacuum molding is as follows: the diameter of the cup-shaped paper container described later: 58.7 mm, the internal height: 8
The height difference between the sealing flange 21 of the drop-down lid member 24 and the top plate 23 was set to 8 mm so that the head space was 10 mm in consideration of 5.6 mm and the content: 200 ml (distilled water).

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 in the following configuration.

[Outside of Container] CPP film (propylene-ethylene block copolymer type, melting point: 160 °)
C, 30 μm thickness) / ivory (160 g / m ² ), diatomaceous earth coating amount; 15 g / m ² / PET film (12 μm)
m thickness), silicon oxide vapor deposited thin film (400 °) / CPP film (propylene-ethylene block copolymer type, melting point: 160 ° C, 30 µm thickness) [inside of container]

Next, the seal flange 21 of the drop-in lid member 24 and the inner surface side of the lid sheet portion 25 were heat-sealed by ultrasonic sealing to form a heat-sealed portion 21a. (The space 2 is located between the top plate 23 and the lid sheet 25.
6 are formed. )

The drop-in cover member 24 provided with the heat-sealed portion 21a and the cover sheet 25 are formed in a cover material shape (diameter: 58.7).
mm).

This was set in a mold for insert molding, and hot melted PP resin was injected from a gate to form an end face covering member 30.

The PP resin used at this time was PP resin and LDP
It is a blend resin with E resin, and the compounding ratio is PP resin / L
DPE resin = 100/30. In addition, PP resin and L
The physical property values of the DPE resin are as follows.・ PP resin: block polymer, MFR = 30 g / mi
n. , Melting point = 161 ° C. LDPE resin: MFR = 25 g / min. , Melting point = 1
20 ° C

In this manner, the paper container lid 20 of the present invention capable of being subjected to the retort sterilization treatment was produced.

Separately, a cylindrical cup paper container having the following structure was manufactured as a cup-shaped paper 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
Thickness), Silicon oxide vapor deposited thin film (400mm) / CPP film (50μm thickness) [inside of container]

Layer structure of tape-shaped laminated film, CPP film (30 μm thick) / PET film (12 μm
Thickness), Silicon oxide vapor deposited thin film (400mm) / CPP film (30μm thickness)

The CPP film used for the laminated sheet and the tape-shaped laminated film has the following composition and physical properties:
It is a P film formed of the same type of PP resin as the PP resin used for the lid material molding section. That is, propylene-ethylene block copolymer, melting point: 160 ° C.,
Density: 0.90 g / cm ³ , MFR: 8 g / 10 mi
n. -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%.

In order to form a cup-shaped container from the laminated sheet, a body member blank serving as the body 11 of the container and a bottom member roll serving as the bottom 13 were prepared. 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 cylinder 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-like 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 molding of the cup-shaped paper container, 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 incurd at the bottom of the manufactured paper container, and the bottom incurred annular member 15 is injected into the inker. A paper container coated with hot-melt 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 constitution 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 paper container thus prepared was filled with 200 ml of distilled water at 65 ° C., and the opening was covered with the same lid, and the peripheral edge member of the container body and the lid material film were ultrasonically sealed. The paper container is sealed by heat fusion according to the method,
Example 1 was used (see FIG. 2).

<Comparative Example 1> The same structure as in Example 1 was used except that the lid material of Example 1 except for the drop-in lid material was used as the lid material. Distilled water at 65 ° C was placed in a paper container. 20
The container was filled with 0 ml and sealed to obtain a sealed paper container of Comparative Example 1 (detailed description is omitted. The drop-off lid member is eliminated as compared with Example 1).

Comparative Example 2 The same configuration and shape as in Example 1 except that a 9 μm-thick aluminum foil was used instead of a PET film on which a silicon oxide thin film was deposited as a barrier layer of a laminated sheet constituting a paper container. The container was filled with 200 ml of distilled water at 65 ° C. and sealed to obtain a sealed container of Comparative Example 2 (detailed description is omitted).

<Comparative Example 3> Instead of the lid material of Example 1,
[Outside of container] ONy film (16 μm thickness) / PET film (12 μm thickness), evaporated silicon oxide thin film (400 mm)
Example 1 except that a laminated film having a structure of / Easy peel PP film (50 μm thick) [inside of container] was used.
Use a paper container of the same configuration and shape as in
Was filled and sealed to obtain a sealed paper container of Comparative Example 2 (detailed description is omitted).

Reference Example 1 As a container, a plastic container having the same shape as in Example 1 (constitution was made of PP resin / ethylene vinyl alcohol copolymer resin (EVOH) / PP resin) was used. Use the lid material used in
The container was filled with 200 ml of 65 ° C. distilled water and sealed to obtain a sealed container of Reference Example 1 (detailed description is omitted).

As described above, container deformation, retort suitability, and microwave oven suitability after hot filling were tested for four types of paper containers and one type of plastic container filled with 200 ml of 65 ° C. distilled water according to the methods described below. And evaluated.

<Experiment 1> Deformation of container after hot filling Five containers of Example 1, Comparative Examples 1, 2, 3 and Reference Example 1, which were filled with 200 ml of distilled water at 65 ° C. and sealed, were placed at room temperature (23 ° C.). The presence or absence of deformation of the container body when allowed to cool to C) was visually observed. Table 1 shows the results. In Table 1,
○ indicates that there is 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) Three containers of Example 1, Comparative Example 2 and Reference Example 1 filled with 200 ml of distilled water lowered to room temperature were manufactured by HISAKA CORPORATION under the following two conditions. Using the apparatus described in (1), an air-containing retort sterilization treatment was performed, and the presence or absence of deformation of the container after the retort sterilization was visually observed. Table 2 shows the results. Table 2
Among them, ○ indicates that there is no shape change such as deformation in both the container body and the lid member, and X indicates that the lid member was dented and deformed. Condition 1 ‥‥ Initial temperature; 80 ° C., temperature rising condition; 120 ° C. reached 15 minutes Holding condition: 30 minutes, cooling time; 30 minutes Condition 2 ‥‥ Initial temperature; 80 ° C., temperature rising condition; 130 ° C. Arrival 15 minutes Holding condition: 30 minutes, cooling time: 30 minutes

<Experiment 3> Suitability of retort (2) The three types of containers of Example 1, Comparative Example 2, and Reference Example 1 were filled with the following oxygen barrier detecting material as a content instead of 200 ml of distilled water. A retort sterilization treatment was performed under two conditions, and the presence or absence of oxygen barrier properties was visually observed. Table 2 shows the results. Oxygen barrier detection material も の 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 こ と 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 three types 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 condition ‥‥ Heating time 3 minutes In Table 3, ○ indicates a state where reheating by a microwave oven was successfully performed, and X indicates a state where reheating by a microwave oven was not performed.

[0068]

[Table 1]

[0069]

[Table 2]

[0070]

[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 the microwave oven suitability after retort sterilization (Example 1).

[0072]

The cover material for a paper container of the present invention absorbs the depressurized state of the container, so that the deformation of the container is prevented and the appearance of the container is not impaired.

Further, since the PP film used inside the container is made of a blended resin whose adhesive strength is adjusted by the ratio of the ethylene-based olefin resin and the PP resin, the heat-sealed lid is used when opening the container. From the container with an appropriate adhesive strength.

Since a barrier film is used,
Since it has content protection properties and does not use metal foil such as aluminum foil, it has microwave oven suitability as well as retort sterilization suitability.

[Brief description of the drawings]

FIG. 1A is a plan view showing one embodiment of a lid member of the present invention, and FIG. 1B is a cross-sectional view taken along line AA ′.

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

FIG. 3 is an explanatory sectional view of a paper container capable of being subjected to a retort sterilization treatment used in Example 1.

[Explanation of symbols]

 10 cup-shaped paper container 11 trunk 12 mouth edge 13 bottom 14 tape-shaped laminated film 15 bottom incurred annular member 16 edge margin member 20 lid 21 {Seal flange 21a} Heat-fused part 22} Peripheral wall 23} Top plate 24} Drop-down lid part 25 {Lid film part 26} Space part 29} Opening handle part 30} End face covering member

Claims (9)

[Claims] 1. A lid material for sealing an opening of a retort-sterilizable cup-shaped paper container having an opening part whose outer periphery curls outward and whose upper and lower layers are flatly thermocompression-bonded to each other, The lid is provided on the top plate, a peripheral wall that can be in close contact with the inner wall of the body of the cup-shaped paper container erected on the peripheral edge of the top plate, and provided on the upper edge of the peripheral wall outward in parallel with the top plate. The sealing flange, the dropping lid material part, and the dropping lid material part, which covers the entirety, forms a space between the top plate, and the lid material sheet part that is heat-sealed with the seal flange, The outer surface and the end surface of the dropped lid material portion and the outer surface and the end surface of the dropped lid material portion and the heat-sealed portion of the dropped lid material portion and the lid material sheet portion at a depth approximately half inward from the edge, End-face covering member that is covered so as to be fitted and that is placed so as to be heat-fusible to the rim of the cup-shaped paper container. , And the end face covering member is provided by an insert injection molding method of injecting a hot-melted polypropylene resin into a mold in which a heat-sealed drop-down lid member and a lid sheet portion are previously inserted and arranged. A lid material for a paper container which can be subjected to a retort sterilization treatment. 2. An opening handle portion is formed on a peripheral edge of said end surface covering member, said opening handle portion partially projecting outward from an edge portion when a lid material is put on a paper container opening. Item 4. A cover material for a paper container which can be subjected to a retort sterilization treatment according to Item 1. 3. The lid sheet section is a laminated sheet having at least a four-layer structure in which a polypropylene (PP) film, a paperboard, a barrier film, and a PP film are laminated in this order from the outside of the container. Claim 1
Or a cover material for a paper container which can be subjected to a retort sterilization treatment according to item 2. 4. A PP used on the inner and outer surfaces of the cover sheet portion.
The retort sterilizable paper container lid according to claim 1, wherein the film is obtained by forming a PP resin having a melting point of 150 ° C or more. 5. 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. The lid material for a paper container capable of being subjected to a retort sterilization treatment according to claim 1, 2, 3, or 4. 6. The paperboard constituting the lid material sheet portion, wherein the paperboard surface is coated with a diatomaceous earth coat layer of 10 to 18 g / m ² .
6. A lid material for a paper container which can be subjected to a retort sterilization treatment according to 2, 3, 4 or 5. 7. The dropping cover part is made of a thermoplastic resin film having a single-layer structure or a two-layer structure or more using PP resin at least on a joint surface with the cover material sheet part, and
The melting point of all thermoplastic resin films used is 140 °
C, or more, 1, 2, 3, 4,
7. A lid material for a paper container which can be subjected to a retort sterilization treatment according to 5 or 6. 8. The PP resin used for the insert injection molding method, wherein the PP resin used for the end face covering member is PP resin.
Resin and low density polyethylene (LDPE) resin or PP
A resin blended with a resin and an ethylene-butene copolymer resin, respectively.
4. A lid material for a paper container which can be subjected to a retort sterilization treatment according to 4, 5, 6 or 7. 9. The blend ratio of the PP resin and the LDPE resin or the PP resin and the ethylene-butene copolymer resin is 100/10 to 100/30, respectively. 4, 5, 6, 7, or 8
A cover material for a paper container which can be subjected to the retort sterilization treatment according to the above.