JPH11292116A - Retort-sterilizable paper container lid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lid which is applicable to a retort-sterilizable paper container. SOLUTION: The lid comprises a drop-in lid portion 24 having a top plate 23, a peripheral wall 22 which can be in tight contact with an internal wall of a body of a cup-like paper container standing on a periphery of the top plate and a seal flange 21 provided in parallel to the top plate 23 outwardly on an upper rim of the peripheral wall 22, a lid sheet portion 25 for covering the whole drop-in portion to form a space 26 from the top plate, and an end face covering member 30 of a U-shaped cross section for covering three directions including an end face of a periphery of a periphery of the lid sheet portion. The seal flange 21, the end face covering member 30 and the periphery of the lid sheet portion 25 are heat-fused to one another and heat-fusibly mounted on a mouth rim of the cup-like paper container. In this case, the end face covering member 30 is provided by insert injection molding technology for injecting a heat-fused PP resin into a mold with the lid sheet portion 25 inserted 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, the lid material being a top plate, and a torso inner wall of the cup-shaped paper container standing upright on a peripheral edge of the top plate. Between a top wall that covers the whole of the dropping cover part, and a top cover that covers the whole of the dropping cover part, and a peripheral wall that can be in close contact with the ceiling wall, and a seal flange that is provided on the upper edge of the peripheral wall outward and parallel to the top plate. A lid material sheet portion that forms a space portion, and an end surface covering member having a U-shaped cross section that covers three directions including an end surface of the lid material sheet portion peripheral edge,
And a lid material that is heat-fused with the seal flange, the end surface covering member, and the lid material sheet peripheral edge covered with the end surface covering member, and that is placed on the edge of the cup-shaped paper container so as to be heat-fusible. The end face covering member is provided by an insert injection molding method for injecting a hot-melted polypropylene resin into a mold in which a lid material sheet is inserted and arranged in advance, wherein the paper container is capable of being subjected to a retort sterilization process. It is a cover material.

Further, according to the invention described in claim 2, when a cover material is put on the opening of the paper container around the peripheral edge of the end face covering member,
A cover material for a paper container which can be subjected to a retort sterilization process, wherein an opening handle portion protruding partly outward from an edge portion is formed.

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 with a top plate, a peripheral wall erected on the periphery of the top plate, which can be in close contact with the inner wall of the body of the cup-shaped paper container, and an upper edge of the peripheral wall. A sealing flange provided outwardly in parallel with the top plate, a dropping lid material portion, and a lid material sheet portion that covers the entire dropping lid material portion and forms a space between the top plate and , An end covering member having a U-shaped cross section that covers three directions including the end surface of the lid material sheet peripheral edge, and the seal flange, the end surface covering member, and the lid material sheet peripheral edge covered with the end surface covering member are mutually separated. Since the lid material is heat-sealed, even if it is cooled after hot filling, the depressurized state in the container is absorbed in the space, and 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. When 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 sheet portion 25 that covers the entire portion and forms a space portion 26 with the top plate, and an end surface covering member 30 having a U-shaped cross section that covers three directions including an end surface of the peripheral portion of the cover sheet portion.
And is composed of

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 end-face covering member 30 is an annular PP having a U-shaped cross section that covers three directions including the end face of the peripheral edge of the lid sheet portion 25.
It is a resin molded member.

The peripheral surface of the cover sheet portion 25 of the end surface covering member 30 is coated by an insert injection molding method in which hot melted PP resin is injected into a mold in which the cover sheet portion 25 is inserted and arranged in advance.

As the PP resin used for the end surface covering member 30, a resin obtained by blending a PP resin and an LDPE resin or a resin obtained by blending a PP resin and an ethylene-butene copolymer resin 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 face covering member 30, an opening handle portion 29 that partially projects outward from the edge of the paper container is provided to open the paper container. When
Opening is easier.

The drop-in lid part 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 material sheet part 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.

[0034] A barrier resin layer may be provided in the layer structure of the drop-in lid member portion 24, and an ethylene vinyl alcohol copolymer resin (EVOH), a 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-in lid member portion 24 is 150 μm or more, and it is manufactured by a pressure forming method or a vacuum forming method.

The squeezing amount (height difference) of the drop-in lid member 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.

Finally, the cover sheet portion 25 whose peripheral edge is covered with the end surface covering member 30 is placed between the top plate 23 and the space portion 26.
Is formed so as to cover the cover member portion 24 so that
The end face covering member 30 and the seal flange 21 were heat-sealed by a sealing method such as an ultrasonic sealing method, whereby a lid material for a paper container capable of being subjected to the retort sterilization treatment of the present invention was produced. If the drop-in lid part 24 and the lid part sheet part 25 covered with the end surface covering member are designed to have substantially the same diameter, a lid with a beautiful appearance is finished.

[0038]

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 and dropped into a lid member 24.

The squeezing amount (level difference) of the vacuum molding is as follows: diameter of cup-shaped paper container: 58.7 mm, internal height: 8
In consideration of 5.6 mm and the internal capacity: 200 ml (distilled water), the head space was reduced to 10 mm, and the height difference between the sealing flange 21 of the lid member 24 and the top plate 23 was set to 8 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 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 laminated sheet is cut into a predetermined size to form a lid material sheet portion 25, and plastic molded products having a U-shaped cross section are fitted in three directions including the end surface of the peripheral edge of the lid material sheet portion. Thus, the end face covering member 30 was formed.

The attachment of the end surface covering member 30 to the cover sheet portion 25 was performed as follows. That is, the cover sheet portion 25 was set in an insert molding die, and the end surface covering member 30 was formed on the periphery of the cover material sheet portion 25 by a method of injecting hot melt PP resin from a gate.

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

Lastly, the cover material sheet portion 25 whose peripheral edge is covered with the end surface covering member 30 is dropped so as to form a space 26 between the top plate 23 and the lid material sheet portion 25, and is placed on the cover material portion 24. Seal flange 2 of member 30 and drop-in lid material
1 was thermally fused by an ultrasonic sealing method to produce a paper container lid material 20 of the present invention which can be subjected to the retort sterilization treatment.

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 was hermetically sealed by heat fusion according to the method described in Example 1 (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 lid material for paper containers of the present invention has a high paper conversion rate and is excellent in disposability. Since the reduced pressure state of the container is absorbed, deformation of the container can be 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 an explanatory plan view showing an embodiment of a lid member according to the present invention, and FIG. 1B is an explanatory sectional view taken along line AA ′.

FIG. 2 is an explanatory cross-sectional view showing a state in which the lid member of Example 1 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 22} Peripheral wall 23} Top plate 24} Drop-down lid part 25} Lid part film part 26} Space part 29} Opening handle part 30} End face covering member

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B65D 81/34 B65D 81/34 U

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 member is provided with a top plate, a peripheral wall erected on the peripheral edge of the top plate, which can be in close contact with the inner wall of the body of the cup-shaped paper container, and provided on the upper edge of the peripheral wall outward in parallel with the top plate. Three-dimensional including a dropping lid material portion, a dropping lid material portion, a lid material sheet portion that covers the entire dropping lid material portion and forms a space between the top plate, and an end surface of the lid material sheet portion peripheral edge. A sealing flange, an end covering member, and a lid material sheet peripheral portion covered with the end covering member are thermally fused to each other, and the edge of the cup-shaped paper container is formed. A lid material that can be thermally fused to the part, wherein the end surface covering member is a lid material sheet. Previously inserted and arranged the retort sterilization can be paper container lid, characterized in that provided by insert injection molding method of injecting a hot molten polypropylene resin in the mold. 2. An opening handle portion is formed on a peripheral edge of the end surface covering member so as to partially protrude outward from an edge portion when a lid material is put on a paper container opening. Claim 1
A cover material for a paper container which can be subjected to the retort sterilization treatment according to the above. 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.