JPH0516976A - Container lid - Google Patents

Abstract

PURPOSE:To eliminate the need to place a weight on a lid which has been put back in place after opening a container and then pouring hot water therein by imparting a specific property to the lid having a pull tab at its edge. CONSTITUTION:The lid having a pull tab 11 at its edge is a laminated product consisting of a base material layer 2 provided on its surface with a printed paper having a Clark stiffness number of 1-20 and a thermoplastic resin film having a tensile elastic modules of 5000-50000kg/cm<2>. The pull tab portion 11 of the lid 1 is given a direction (a) directed in coincidence with the direction of a larger thermal expansion coefficient of the lid taking place when the temp. of the thermoplastic resin film of the base material layer 2 is made to rise to 30-80 deg.C in an increment of 10 deg.C per minute for five minutes and the pull tab portion 11 of the thermoplastic resin film is given a direction in the direction of the film thermal expansion coefficient of 0.4-2.4%. The thickness of the thermoplastic resin film of the base material layer 2 is made larger than that of a metal layer 4. This can eliminate the need to place a weight on the lid 1 which has been put back in place after pouring hot water in the container.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat-sealing of a container for instant food such as instant cup noodles, cup sushi, cup soup, and cup miso soup, which is eaten after pouring hot water into the container and holding it for a certain period of time. Regarding the lid used.

[0002]

2. Description of the Related Art Conventionally, instant foods represented by instant cup noodles can be eaten simply by pouring hot water into a container and waiting for a few minutes (1 to 5 minutes). It is eaten in large quantities by singles, factory night workers, single employees, students, and others. In order to eat such an instant food, for example, the case of instant cup noodles will be specifically described. First, the transparent shrink wrapping film packaged at the time of purchase is removed, and then the container is heat-sealed ( The pulling part of the heat-sealed lid is picked up by fingers and pulled up, and about 1/3 to 1/2 of the lid is peeled off from the container.
Then, the bag containing the ingredients and soup other than the noodles in the container is cut with fingers, placed on the noodles, and boiling water is poured into this. After pouring hot water, the part of the peeled lid is placed on the flange portion at the upper end of the container to close the lid, and a weight is placed on the lid so that the lid does not roll up and open, or The heat in the container is prevented from escaping by using tape or the like to improve the heat efficiency, and the contents are steamed. And
After a lapse of a predetermined time (1 to 5 minutes), the weight on the lid is removed, the rolled-up lid is pulled, the lid is completely peeled off from the container, and the contents are steamed. Can eat.

As a container used for such instant foods, polystyrene paper, a high-impact polystyrene sheet, or a laminated sheet of nylon and polyethylene, which have a good heat retaining property, is usually cup-assisted by plug-assist vacuum forming or pressure forming. A molded product, a foam polystyrene cup obtained by in-mold bead foam molding, a container obtained by injection molding polypropylene, and the like are used. Further, as the lid used for the above-mentioned container, as shown in FIG. 7, the thickness having the printing 7 on the surface is 70 to 8
An adhesive layer 3 having a thickness of 15 to 25 μm or a urethane-based or polyester-based adhesive layer 3 in which 0 μm high-quality paper is used as a base material layer 2 and a molten resin film of low density polyethylene or ethylene / acrylic acid copolymer is extrusion coated Liquid adhesive (so-called anchor coating agent) applied wall thickness 1-5μ
m adhesive layer 3, an aluminum foil layer 4 obtained by laminating an aluminum foil having a thickness of 6 to 15 μm, and a low melting point of low density polyethylene or ethylene / vinyl acetate copolymer (80 ~ 135 ° C) Extrusion laminate or resin dissolved in a solvent to apply a thickness of 2 to 25 μm
The laminated sheet 6 having the four-layer structure and having the heat-sealing property was used.

[0004]

However, such a lid of an instant food container has such a feature that when the lid of the container is partially opened and hot water is poured, the steam of the hot water passes through the aluminum layer on the inside of the lid to form a base material. As a result of heating the high-quality paper and releasing the water content in the high-quality paper, the high-quality paper contracts, the lid curls upward, and warps back (see FIG. 5). Therefore, the lid of an instant food container cooked with this kind of hot water conventionally requires the trouble of pouring hot water and then closing the lid of the opened lid by weighting the lid. It was

[0005]

[Means for Solving the Problems]

[Summary of the Invention] As a result of intensive studies in view of the above problems, the present inventors have found that thermal expansion between the printed paper and the metal foil can be greater than that of the metal foil due to the temperature of steam. Moreover, the thermal expansion is not so large as to cause the lid to curl inward, and a thermoplastic resin film having a specific structure and / or specific physical properties is interposed, and Even if the paper shrinks, the lid does not curl upward (on the side opposite to the container) even if the paper shrinks, and the container has a specific rigidity so that the container can close itself. The present invention has been completed by finding that the lid can automatically close the container by supplying hot water into the container by selecting one.

That is, the lid of the first container of the present invention is
A lid which is composed of a laminated sheet of a base material layer / adhesive layer / metal layer / heat-sealable resin layer and is used for sealing a container,
And, via the heat-sealable resin layer, the lid heat-sealed to the container, a lid having a pulling portion at the end for peeling from the container, the following (1) ~ (3 ) Is provided. (1) The base material layer is paper (A) having a Clark stiffness value (S value measured by JIS-P8143) of 1 to 20 printed on the surface, and a tensile elastic modulus of 5,000 to 50,000 kg.
/ Cm ² of the thermoplastic resin film (B) is a laminate, (2) The direction in which the tension portion of the lid is provided is such that the temperature rising rate of the thermoplastic resin film (B) of the base material layer is 10 ° C./min. The thermoplastic resin film (B) is provided with a pulling part in such a manner that it is aligned with the direction in which the coefficient of thermal expansion is large when the temperature is raised from 30 ° C. to 80 ° C. over 5 minutes. The coefficient of thermal expansion in the direction indicated by the arrow is 0.4 to 2.4%, (3) the thickness of the thermoplastic resin film (B) of the base material layer is
Greater than the thickness of the metal layer.

The lid of the second container of the present invention comprises a laminated sheet of base material layer / adhesive layer / metal layer / heat-sealable resin layer, and is a lid used for sealing the container, and On the surface of the lid that is heat-sealed to the container via the heat-sealable resin layer, the lid instructed by printing the direction of peeling from the container has the following properties (1) to (3). It is characterized by being provided. (1) The base material layer is paper (A) having a Clark stiffness value (S value measured by JIS-P8143) of 1 to 20 printed on the surface, and a tensile elastic modulus of 5,000 to 50,000 kg.
/ Cm ² of the thermoplastic resin film (B), (2) The surface of the paper (A) that indicates the direction of peeling the lid is printed on the thermoplastic resin film (B ) Is heated at a temperature rising rate of 10 ° C./minute for 5 minutes from 30 ° C. to 80 ° C., and the direction is matched with the direction in which the coefficient of thermal expansion is large, and printing is performed. The coefficient of thermal expansion of the thermoplastic resin film (B) in the peeling direction of the lid is 0.4 to 2.4%, (3) the thickness of the thermoplastic resin film (B) of the base material layer. Is
Greater than the thickness of the metal layer.

[Detailed Description of the Invention] [I] Container Lid (1) Structure As shown in FIG. 1, the container lid 1 of the present invention basically has the following base material layer 2 / adhesive layer. 3 / metal layer 4 / heat-sealable resin layer 5 is composed of a laminated sheet 6, and the base layer 2 is a paper 2a on which printing 7 is applied,
It is made of a thermoplastic resin film 2b. An adhesive layer 2c may be present between the base material layer 2a and the thermoplastic resin film 2b, if necessary. The thermoplastic resin film 2b may be a single layer film (see Examples 1 and 2 below) or a composite structure of two or more layers (see Examples 3 and 4 below).

(A) Base Material Layer The base material layer 2 used in the lid 1 of the container of the present invention comprises the paper 2a having the surface printed as described above and the thermoplastic resin film 2b. As the paper 2a, art paper,
Pulp paper such as clay-coated paper, glassine paper and tobacco paper can be used, and these papers have a Clark stiffness (S value) of 1 to 20, preferably 3 to 20. When the Clark stiffness value of paper exceeds 20, the lid does not close even if hot water is supplied into the container, or the lid warps to the side opposite to the container side. The thickness of the paper exhibiting such Clark stiffness varies depending on the type of paper, but is usually 20 to 65 μm. The thermoplastic resin film 2b has a tensile elastic modulus of 5,000 to 50,000 kg.
/ Cm ² , preferably 6,500-36,000 kg / cm ²
Is. If it is less than 5,000 kg / cm ² , the lid tends to warp upward (paper side) when hot water is supplied into the container. Also,
The thermoplastic resin film 2b has a coefficient of thermal expansion in a direction in which the lid is peeled off (when the film 2b is heated to a temperature of 30 to 80 ° C over 5 minutes at a temperature rising rate of 10 ° C / minute). It is necessary that the coefficient of thermal expansion) be 0.4 to 2.4%. If the coefficient of thermal expansion is less than 0.4%, the lid will not close automatically when hot water is supplied. In the case of a shrinkable polyethylene stretched film or a polyvinyl chloride stretched film that has a negative expansion coefficient due to heat shrinkage, the lid curls inward as shown in FIG. 6 after self-closing. . The Clarke stiffness (S value) of the thermoplastic resin film 2b is generally 5 to 40. As the thermoplastic resin of the film material, polypropylene, polycarbonate, polyphenylene ether, ethylene / propylene copolymer, propylene / 4-methylpentene-1 copolymer, propylene / ethylene / butene-1 copolymer, polystyrene, polyethylene Terephthalate, nylon-6, nylon-
6,6, nylon-6,10, nylon-6,12, saponified ethylene / vinyl acetate copolymer, and the like.

<Thermal Expansion Coefficient> In the container lid of the present invention, the thermal expansion coefficient (L _e ) of the thermoplastic resin film 2b of the base material layer.
is important. This coefficient of thermal expansion was measured using a thermomechanical analyzer "TM-7000" (trade name) manufactured by Vacuum Riko Co., Ltd.
A test piece having a width of 5 mm and a length of 25 mm was used, and the test piece was fixed to a chuck. The span distance (L ₀ ) was 15 mm and the load was 1.
g, then 30 ° C over 5 minutes at a heating rate of 10 ° C / min
The temperature is raised from 80 ° C. to 80 ° C., the span length (L) of the test piece at the temperature of 80 ° C. is measured, and the value obtained by the following formula (TMA method) is shown. Thermal expansion coefficient = [(L−L ₀ ) / L ₀ ] × 100 The value of this thermal expansion coefficient is 0.40 to 2.4%, preferably 0.55 to 2.40%. The value of this coefficient of thermal expansion is 2.
If it exceeds 4%, as shown in FIG. 6, the self-closing speed of the lid after pouring hot water into the container is too fast, before the contents have been steamed (before the cup noodles are ready to eat). The pulling part of the lid that has closed itself too much is caught inward, and a gap 10 is created between the container 9 and the lid 1. When the value of the coefficient of thermal expansion is less than 0.40%, the time required for self-closing is too slow (takes 90 seconds to 3 minutes), causing irritation to the eater or losing the paper contraction. The lid may not close, or the lid may warp to the side opposite to the container side as shown in FIG. TM of the thermoplastic resin film 2b of the base material layer
The value of the coefficient of thermal expansion obtained by the method A is affected by the material of the resin film, the layer structure, the thermal history received during the film molding, the orientation, and the like. Therefore, depending on the resin material, inorganic fine powder may be blended with the resin, and the desired physical properties may be obtained by adjusting the stretching ratio, stretching temperature, cooling roll pressure, temperature, and the like. The thickness of the resin film 2b also contributes. The resin film 2b generally has a wall thickness of 15-18.
It is 0 μm, preferably 40 to 100 μm. The tensile modulus of the base material layer of the resin film 2b in the lid peeling direction α or in the direction δ in which the tension portion of the lid is provided (JIS-
K7113) is 5,000 to 50,000 kg / cm
² , preferably 6,500 to 36,000 kg / cm ²
Is. In the case of a stretched film, since the orientation is applied to the film, the elastic modulus is higher than that of the non-stretched resin film. Therefore, the thickness of the resin film 2b can be reduced. Paper 2a and thermoplastic resin film 2
For the bonding of b, the thermoplastic resin film 2b may be extrusion-laminated and bonded onto the paper 2a, or the adhesive layer 2c may be formed using an adhesive to bond the two. The adhesive used for the adhesive seat layer 2c can be selected and used from those used for the adhesive layer 3 described in the next section in which the base material layer 2 and the metal layer 4 are conventionally adhered.

(B) Adhesive Layer As the adhesive layer 3 laminated for bonding the base layer 2 and the metal layer 4 such as an aluminum foil described later in the lid of the container of the present invention, a urethane prepolymer, Liquid polyester, isocyanate type, polyester isocyanate type, polyether isocyanate type, polyethyleneimine type, organic titanate type anchor coating agent, low density polyethylene, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, etc. Mention may be made of melt adhesives. The coating type adhesive is 1-2
It is used in an amount of 0 g / m ² , preferably 2-6 g / m ² . Hot melt adhesive is melt extrusion laminated, 8
Used with a thickness of ~ 30 μm. Such an adhesive layer is generally used in a thickness of 1 to 30 μm, preferably 2 to 15 μm.

(C) Metal Layer As the metal layer 4 used in the container lid of the present invention, a metal foil such as an aluminum foil or an iron foil having a wall thickness of usually 3 to 25 μm can be mentioned. Especially the wall thickness is 6-1
It is preferable to use a 5 μm aluminum foil for the reasons of handling and economical reasons. Further, from the economical aspect, the metal foil is usually used with a thickness smaller than that of the base material layer 2.

(D) Heat-sealable resin layer As the heat-sealable resin layer 5 used for heat-sealing the container and the lid in the present invention, a heat having a melting point lower than that of the resin constituting the base material layer 2 is used. A sealing resin is used. Specific examples of such heat-sealable resin include:
Low density polyethylene, linear low density polyethylene, ethylene / vinyl acetate copolymer (preferably ethylene / vinyl acetate copolymer having a vinyl acetate content of 12% by weight or less), ethylene / acrylic acid copolymer (preferably ethylene content) Of 65-94% by weight of ethylene / acrylic acid copolymer), ethylene / methacrylic acid alkyl ester copolymer, ionomer (metal salt of ethylene / acrylic acid copolymer, metal salt of ethylene / methacrylic acid copolymer) , Ethylene / propylene copolymer, ethylene / propylene /
Examples thereof include butene-1 copolymer and vinyl chloride / vinyl acetate copolymer. The heat-sealable resin layer 5
May be extrusion laminated coated on a metal sheet such as an aluminum foil, or the resin may be dissolved in a solvent, coated on the aluminum foil using a coater, and dried to form the heat-sealable resin layer 5. Is also good. The heat-sealable resin layer 5 has a wall thickness of 2 to 50 μm, preferably 3 to 40 μm. The heat-sealing of the container and the lid using such a heat-sealable resin can prolong the shelf life of the food in the container.

(2) Tear-off direction of lid In the lid 1 of the container of the present invention, as shown in FIG.
A pulling portion 11 for peeling off the lid 1 is provided, or a display 8 for instructing the peeling direction α is printed 7 on the lid as shown in FIG. In the present invention, the position where the pulling portion 11 is formed or the printed direction 7 of the display 8 that indicates the peeling direction α is important. Since the peeling direction α indicated by the pulling portion 11 of the lid 1 or the display 8 coincides with the peeling direction α of the lid 1, the lid 1
It is desirable to provide the base material layer 2 so as to match the direction β in which the coefficient of thermal expansion of the base material layer 2 is large, in order to promote the self-closing property. If the pulling portion 11 of the lid 1 or the peeling direction α by printing is provided so as to match the direction γ having a small coefficient of thermal expansion, the self-closing property is deteriorated.

(3) Thickness of Lid The thickness of the lid 1 made of the laminated sheet 6 is generally 40 to 2
00 μm, economically 60 to 150 μm.

[II] Manufacture of container with lid (1) Heat-sealing Basically, base layer 2 / adhesive layer 3 / metal layer 4 / heat-sealing property, which becomes the lid 1 of the container of the present invention formed as described above. A laminated sheet 6 composed of the resin layer 5 is provided inside the dried noodles 12 and the ingredients 13
It is placed on a container 9 in which is put and heat-sealed at a temperature of usually 100 to 160 ° C., preferably 120 to 140 ° C. for 0.1 to 3 seconds. (2) Labeling the contents on the surface of the paper 2a of the printing laminated sheet 6, the manufacturer,
Offset printing or gravure printing of manufacturing date etc. When the pulling portion is not formed, printing for instructing the lid peeling direction is also performed as shown in FIG. (3) Formation of pulling part The container 9 heat-sealed to the laminated sheet 6 is a separate container 9
In order to form the pulling portion 11 by separating each piece, a substantially circular shape (for example, a diameter of 150 m
The lid 1 having the protrusion 11 (tensile portion) of about 10 mm with respect to m is trimmed. (4) Shrink packaging Next, the sealed container 9 thus obtained is shrink-wrapped to form a product.

[III] The lid 1 opened halfway through the hot water supply is heated by the steam supplied, and the base material layer 2 is subjected to the thermal expansion of the metal layer 4 of the material forming the lid 1.
Of the thermoplastic resin film 2b is superior to the thermal expansion force of the film 2b, and the thermal expansion force of the film 2b is superior to the contraction force of the paper 2a of the base material layer, and the lid 1 is automatically in the original position due to the bimetal effect. The container 9 can be sealed by returning to (see FIG. 2).

[0018]

【Example】

Example 1 Manufacture of base material layer "Cormorant" coated paper manufactured by Fuji Kako Co., Ltd. (trade name;
Wall thickness 46 μm, basis weight 50.0 g / m ² , Clark stiffness 1
The surface of the back side of 3.7) was coated with a urethane prepolymer primer at a rate of 3 g / m ² on the surface.
Stretched polypropylene film “PB-262” (trade name; wall thickness: 50 μm, tensile elastic modulus (MD direction): 2)
2,150 kg / cm ² , Clark stiffness in machine direction (MD direction): 9.4, melting point: about 164 ° C., thermal expansion coefficient in machine direction (MD direction): 0.65%, width direction (TD direction) Thermal expansion coefficient: 0.37%, thermal contraction rate in free standing at 80 ° C. for 10 minutes is 0.40% in MD direction, −0.12 in TD direction.
%) Was stuck together by a roll to obtain a base material layer.

Manufacture of Lid The surface of the paper of the base material layer is printed, and a urethane prepolymer anchor coating agent 3 is applied to the back surface side of the base material layer.
It was applied so as to be g / m ^2, and an aluminum foil having a thickness of 6 μm was laminated on this. On the aluminum foil side of this laminate, a toluene solution of ethylene / vinyl acetate copolymer (vinyl acetate content 5.4% by weight) was applied,
It was dried to form a heat-sealing resin layer having a thickness of 4 μm.
This was trimmed so that a tensile portion was formed in the sheet feeding direction (MD direction), and a substantially circular lid was obtained (diameter 150 mm, tensile portion 10 mm). Heat Sealing 250 g of dried noodles and 25 g of ingredients were put in an expanded polystyrene container having an internal capacity of 1,000 cc and a diameter of about 150 mm, and the lid was heat-sealed by applying pressure at 140 ° C. for 0.5 seconds. Evaluation After standing for one day, pull the pulling part of the lid of the expanded polystyrene container with a finger to open 2/3 of the lid, and boil the boiling water (temperature about 91 ° C) from this opening to 600 cc. After pouring into the container for 5 seconds, the self-closing property of the lid (time after hot water supply until closing of the lid) was measured. The results obtained are shown in Table 1.

Example 2 A substrate layer was produced in the same manner as in Example 1 except that it was produced as follows. The results obtained are shown in Table 1. Manufacture of base material layer Non-stretched polypropylene film “Taikaku FHK ₂ ” manufactured by Nimura Sansho Co., Ltd. (trade name; wall thickness 60 μm, basis weight 54.0 g
/ M ² , coefficient of thermal expansion: 2.33% in MD direction, 1.30 in TD direction.
69%, heat shrinkage ratio: MD direction 0.00%, TD direction 0.
01%, tensile modulus: MD direction 8,200 kg / cm ₂ , Clark stiffness: MD direction 4.0), and a urethane prepolymer primer was applied at a rate of 3 g / m ² ,
Clay-coated paper "Cormoran" (Fuji Kogyo Co., Ltd.) (thickness 46 μm, basis weight 50.0 g / m ² ) was laminated on this to obtain a base material layer.

Example 3 In Example 1, a laminated stretched film (thickness: 50 μm) obtained by the following production method was used in place of the biaxially stretched polypropylene film “PB-262” to obtain a lid. Production of laminated stretched film (1) 81% by weight of polypropylene having a melt index (MI) of 0.8 (melting point of about 164 to 167 ° C.), 3% by weight of high-density polyethylene and 16% by weight of calcium carbonate having an average particle size of 1.5 μm The composition (A) containing 270 ° C.
After kneading with the extruder set to, the sheet was extruded and cooled by a cooling device to obtain an unstretched sheet. Then, this sheet was heated again to a temperature of 150 ° C. and then stretched 5 times in the machine direction (MD). (2) Polypropylene with MI of 0.4 (melting point about 164-1)
(67 ° C.) 54% by weight and 46% by weight of calcium carbonate having an average particle size of 1.5 μm were mixed and kneaded in another extruder, and then extruded into a sheet from a die. Was laminated on both sides of the 5-fold stretched film of (1) to obtain a laminated film having a three-layer structure. Then, after cooling the laminated film having the three-layer structure to 60 ° C., it is again cooled to about 175 ° C.
Heat up to the temperature of
D) was stretched 7.5 times, annealed at a temperature of 165 ° C., cooled to a temperature of 60 ° C., and the ears were slit to form a three-layer structure (uniaxial stretching / biaxial stretching / uniaxial stretching). , Wall thickness 50 μm (B / A / B = 12 μm / 26 μm / 12μ
A base material layer of m) was obtained.

Example 4 In Example 1, the biaxially stretched polypropylene film "PB-262" was replaced with a stretched film having a three-layer structure obtained by the following production. ) Made cormorant (wall thickness 60 μm, basis weight 6)
A lid was manufactured in the same manner except that 3 g / m ² and Clark stiffness 19.2) were used. Production of a stretched film having a three-layer structure (1) 81% by weight of polypropylene having a melt index (MI) of 0.8 (melting point of about 164-167 ° C.), 3% by weight of high-density polyethylene and calcium carbonate having an average particle size of 1.5 μm The composition (A) containing 16% by weight is mixed at 270 ° C.
After kneading with the extruder set to, the sheet was extruded and cooled by a cooling device to obtain an unstretched sheet. Then, this sheet was heated again to a temperature of 150 ° C. and then stretched 5 times in the machine direction. (2) Polypropylene with MI of 0.4 (melting point about 164-1)
(67 ° C.) 54% by weight and 46% by weight of calcium carbonate having an average particle size of 1.5 μm were mixed and kneaded in another extruder, and then extruded into a sheet from a die. Was laminated on both sides of the 5-fold stretched film of (1) to obtain a laminated film having a three-layer structure. Then, after cooling the laminated film having the three-layer structure to 60 ° C., it is again cooled to about 175 ° C.
Heat up to the temperature of 7. and use a tenter to move laterally 7.
Stretched 5 times, annealed at a temperature of 165 ° C,
Cooled to a temperature of 60 ° C, slit the ears and have a three-layer structure (uniaxial stretching / biaxial stretching / uniaxial stretching), wall thickness 80 μm
A base material layer (B / A / B = 20 μm / 40 μm / 20 μm) was obtained.

Comparative Example 1 In Example 1, as a coated paper, a cormorant manufactured by Fuji Kako Kaisha Co., Ltd. (thickness 70 μm, Clark stiffness 22.
5, the lid was manufactured in the same manner except that the basis weight of 75.0 g / m ² ) was used.

Comparative Example 2 In Example 2, instead of the unstretched polypropylene film, a multi-layer stretched film "YUPO FPG ^# 60" (brand name, wall thickness 60 μm of polypropylene containing inorganic fine powder manufactured by Oji Yuka Synthetic Paper Co., Ltd.) was used. ) Was used in the same manner as above, but a lid was produced.

Comparative Example 3 A lid was manufactured in the same manner as in Example 2 except that the cormorant of Comparative Example 1 manufactured by Fuji Paper Co., Ltd. was used as the coated paper.

Comparative Example 4 A lid was prepared in the same manner as in Example 1 except that a polyethylene shrink film (thickness 15 μm, melting point 119 ° C., tensile elastic modulus 11,850 kg / cm ² ) was used instead of the biaxially oriented polypropylene film. Manufactured.

Comparative Example 5 A lid was produced in the same manner as in Example 3, except that the laminated stretched resin film produced by the following method was used. Production of laminated stretched film (1) Composition (A) in which 81% by weight of polypropylene having a melt index (MI) of 0.8% by weight is mixed with 3% by weight of high density polyethylene and 16% by weight of calcium carbonate having an average particle size of 1.5 μm. Was kneaded with an extruder set at 270 ° C., extruded into a sheet, and cooled by a cooling device,
An unstretched sheet was obtained. Then, this sheet was heated again to a temperature of 140 ° C. and then stretched 5 times in the machine direction. (2) A composition (B) in which 54% by weight of polypropylene having an MI of 4.0 and 46% by weight of calcium carbonate having an average particle size of 1.5 μm are mixed and kneaded in another extruder, The sheet was extruded into a sheet and laminated on one side of the 5-fold stretched film of (1) to obtain a laminated film having a three-layer structure.
Next, after cooling the laminated film having the three-layer structure to 60 ° C., it is heated again to a temperature of about 160 ° C., stretched 7.5 times in the transverse direction using a tenter, and annealed at a temperature of 165 ° C. Then, it is cooled to a temperature of 60 ° C., and the ears are slit to form a three-layer structure (uniaxially stretched / biaxially stretched / uniaxially stretched) having a thickness of 60 μm (B / A / B = 15 μm / 30).
A base material layer having a thickness of μm / 15 μm) was obtained. The void ratio of each layer was (B / A / B = 30% / 33.7% / 30%).

Example 5 In Example 1, instead of the coated paper “Cormorant”, thin paper (trade name; wall thickness 2 manufactured by Sanko Paper Co., Ltd.) was used in the present specification.
8 μm, basis weight 14.0 g / m ² ) Clark stiffness 3.4)
A lid was manufactured in the same manner except that was used. The pulling parts were provided on all the lids in the MD direction, which has a high coefficient of thermal expansion. Table 1 shows the evaluation results as a cup noodle container.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

EFFECT OF THE INVENTION The lid of the container of the present invention is heated by the steam supplied to the container, whereby the bimetal effect works and the container can be automatically sealed. There is no need to close the lid after the hot water is supplied and place a weight.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a lid of a container according to the present invention.

FIG. 2 is a perspective view of the lid and the container of the present invention in a state where hot water is poured into the container and the lid is automatically closed.

FIG. 3 is a perspective view of the lid and the container of the present invention in a state in which the lid is opened, tools are put in the container, and hot water is not poured.

FIG. 4 is a perspective view of the container lid and the container of the present invention in which hot water is poured into the container and a display for instructing a peeling direction is printed on the lid of the container in a state where the lid is automatically closed. is there.

FIG. 5 is a perspective view of a conventional lid and container in a state where hot water is poured into the container and is further opened.

FIG. 6 is a perspective view of the improper lid and the container in a state in which hot water is poured into the container and is closed too much and curved inward.

FIG. 7 is an enlarged cross-sectional view of a conventional lid.

[Explanation of symbols]

1 Container Lid 2 Base Material Layer 2a Biaxially Stretched Resin Microporous Films 2b, 2c Uniaxially Stretched Resin Microporous Film 3 Adhesive Layer 4 Metal Layer 5 Heat-Sealable Resin Layer 6 Laminated Sheet 7 Printing 8 Indication for Detachment Direction 9 Container 10 Gap 11 Tension part 12 Dry noodle 13 Tool α Peeling direction β Direction with large value of thermal expansion coefficient γ Direction with small value of thermal expansion coefficient θ Direction within 45 degrees to direction β showing large coefficient of thermal expansion Angle δ Direction in which the tension part is provided

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Funato             23 Towada, Kazasu-machi, Kashima-gun, Ibaraki             Kabushiki Kabushiki Kaisha Co., Ltd. (72) Inventor Takashi Miyaji             23 Towada, Kazasu-machi, Kashima-gun, Ibaraki             Kabushiki Kabushiki Kaisha, Ltd. (72) Inventor Yukio Obama             826 Fukuda, Hagizono, Chigasaki-shi, Kanagawa East             Sea Metal Co., Ltd. Chigasaki factory (72) Inventor Kazunori Yamada             826 Fukuda, Hagizono, Chigasaki-shi, Kanagawa East             Sea Metal Co., Ltd. Chigasaki factory (72) Inventor Toshiaki Watanabe             826 Fukuda, Hagizono, Chigasaki-shi, Kanagawa East             Sea Metal Co., Ltd. Chigasaki factory (72) Inventor Chiaki Kanai             826 Fukuda, Hagizono, Chigasaki-shi, Kanagawa East             Sea Metal Co., Ltd. Chigasaki factory

Claims (2)

[Claims] 1. A lid, which comprises a laminated sheet of a base material layer / adhesive layer / metal layer / heat-sealable resin layer and is used for sealing a container, and which is attached to the container via the heat-sealable resin layer. A lid provided with a pulling portion at its end for peeling the lid which is heat-sealed from the container is described in (1) to
A lid of a container having the property of (3). (1) The base material layer is paper (A) having a Clark stiffness value (S value measured by JIS-P8143) of 1 to 20 printed on the surface, and a tensile elastic modulus of 5,000 to 50,000 kg.
/ Cm ² of the thermoplastic resin film (B) is a laminate, (2) The direction in which the tension portion of the lid is provided is such that the temperature rising rate of the thermoplastic resin film (B) of the base material layer is 10 ° C / The thermoplastic resin film (B) is provided with a pulling portion in such a manner that it matches the direction in which the coefficient of thermal expansion is large when the temperature is raised from 30 ° C. to 80 ° C. over 5 minutes. The coefficient of thermal expansion in the provided direction is 0.4 to 2.4%, (3) the thickness of the thermoplastic resin film (B) of the base material layer is
Greater than the thickness of the metal layer. 2. A lid comprising a laminated sheet of a base material layer / adhesive layer / metal layer / heat-sealable resin layer, which is used for sealing the container and which is attached to the container via the heat-sealable resin layer. On the surface of the heat-sealed lid, the lid in which the direction of peeling from the container is instructed by printing is described in (1) below.
A lid of a container having the properties of (3) to (3). (1) The base material layer is paper (A) having a Clark stiffness value (S value measured by JIS-P8143) of 1 to 20 printed on the surface, and a tensile elastic modulus of 5,000 to 50,000 kg.
/ Cm ² of the thermoplastic resin film (B), (2) The surface of the paper (A) that indicates the direction of peeling the lid is printed on the thermoplastic resin film (B ) Is heated at a temperature rising rate of 10 ° C./minute for 5 minutes from 30 ° C. to 80 ° C., and the direction is matched with the direction in which the coefficient of thermal expansion is large, and printing is performed. The coefficient of thermal expansion of the thermoplastic resin film (B) in the peeling direction of the lid is 0.4 to 2.4%, (3) the thickness of the thermoplastic resin film (B) of the base material layer is ,
Greater than the thickness of the metal layer.