JP3412411B2 - Lid material for packaging containers and packaging containers - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging container having excellent heat-sealing property and easy-opening property, and a packaging container. For details, heat seal a container or sheet of thermoplastic resin, especially a polyethylene-coated paper container or sheet made of polyethylene or paper coated with polyethylene, and then easily open (separate) from the container or sheet. The present invention relates to an easily-openable lid material having an openable (peelable) layer and a packaging container using the same.

[0002]

2. Description of the Related Art Polyolefins such as polyethylene and polypropylene, thermoplastic resins such as polyvinyl chloride, polystyrene and polyethylene terephthalate are widely used in various packaging containers because of their excellent appearance, mechanical strength, moldability, wrapping workability and economy. Has been. Further, in consideration of the treatment after disposal, containers in which pulp paper which can be easily incinerated is coated with low-density polyethylene are widely used.

[0003] These packaging containers are mainly filled with dairy products, confectionery, natto, soft drinks, and other food products, and the packaging container in which the container opening portion is sealed is the mainstream, and the demand for these packaging containers is diversified. As a result, not only the protective property of the contents but also the ease of opening the container at the time of use has been required. Conventionally, as a sealing material for these containers, a hot melt adhesive such as polyethylene, ethylene-vinyl acetate copolymer, Surlyn, etc. or a solution type of ethylene-vinyl chloride copolymer, vinyl chloride-acrylic acid alkyl ester copolymer, etc. Adhesives are used, but there is a problem that these adhesives adhere to the container side after opening and the appearance of the unsealed surface becomes poor. Further, since the melting point is generally low and the heat resistance is insufficient, for example, when used in a retort pouch container and boiled together with the container, peeling occurs in hot water, and there is a problem in terms of content protection.

In order to improve these drawbacks, in recent years, various materials having both contents-protecting property and easy-opening property have been proposed. For example, a composition comprising an ethylene-vinyl acetate copolymer and a tackifier is generally used as a heat seal material in a thermoplastic resin container. It is also known that a material mainly composed of an ethylene-vinyl acetate copolymer or a modified resin obtained by modifying polyethylene with an aromatic vinyl monomer exhibits easy-opening property for an olefin polymer. (Japanese Patent Publication No. 1-42967).

On the other hand, an aluminum foil is widely used as a base material for the lid material of a container from the viewpoint of rigidity, etc. In order to provide the above-mentioned easy-open heat-sealing material in the aluminum foil base material layer, the aluminum foil is used. In order to sufficiently adhere the base material layer and the heat-sealing material layer, it is necessary to provide them through the low-density polyethylene layer. That is, the aluminum foil substrate layer is coated with polyethylene and then the heat sealing material, which is not industrially efficient. Also,
When such a heat-sealing material is applied as a heat-sealing material for a container in which the surface of pulp paper is coated with polyethylene, the adhesive strength between the heat-sealing material and polyethylene is the same as the adhesive strength between paper and polyethylene. Since it is higher than the above, there is a drawback that the paper of the base material is destroyed at the time of peeling and the appearance of the container is deteriorated.

[0006]

DISCLOSURE OF THE INVENTION The present invention has an excellent heat-sealing property and can easily be opened without damaging the container or the sheet when opening, and a packaging container using the same. The purpose is to provide.

[0007]

[Means for Solving the Problems] That is, the first aspect of the present invention is that a layer having a thermoplastic resin composition comprising the following components (A) and (B) as a base material is laminated on an aluminum layer. Is a lid material for a packaging container. Component (A): ethylene-unsaturated organic acid copolymer having an unsaturated organic acid content of 5 to 15% by weight 1-90% by weight (B) component: unsaturated organic acid content of 5 to 15% Modified copolymer obtained by subjecting ethylene-unsaturated organic acid copolymer (b1) of 30 to 95% by weight and vinyl monomer (b2) of 70 to 5% by weight to graft reaction conditions. 99-10% by weight

The second aspect of the present invention is a packaging container body (1) having an opening, and a lid member (2) for sealing the opening.
A container body (1) for a packaging container comprising
Is formed by molding a laminated body composed of a polyethylene layer (11) and a paper layer (12), and the lid material (2) is a thermoplastic resin composition comprising the following components (A) and (B): A thermoplastic resin composition layer of a container body (1) and a polyethylene layer (11) of the container body (1) and a lid member (2), the laminate being composed of a material layer (21) and an aluminum layer (22). (21) is heat-sealed to close the opening of the container body, and the polyethylene layer (11) and the thermoplastic resin composition layer (21) can be easily peeled off when the package is opened. It is a container for.

[0009]   Component (A): ethylene-unsaturated with an unsaturated organic acid content of 5 to 15% by weight Organic acid copolymer 1 to 90% by weight   Component (B): ethylene-unsaturated with an unsaturated organic acid content of 5 to 15% by weight 30 to 95% by weight of organic acid copolymer (b1) and 70 to 5% by weight of vinyl monomer (b2) % To 99% by weight of a modified copolymer obtained by subjecting the

[0010]

DETAILED DESCRIPTION OF THE INVENTION

[1] Constituent Components of Lid Material (1) Layer of Thermoplastic Resin Composition (Heat Seal Layer) The thermoplastic resin composition constituting one layer of the lid material of the present invention is
It is a layer having as a base material a thermoplastic resin composition comprising the following components (A) and (B). Component (A): ethylene-unsaturated organic acid copolymer having an unsaturated organic acid content of 5 to 15% by weight 1-90% by weight (B) component: unsaturated organic acid content of 5 to 15% Modified copolymer obtained by subjecting ethylene-unsaturated organic acid copolymer (b1) of 30 to 95% by weight and vinyl monomer (b2) of 70 to 5% by weight to graft reaction conditions. 99-10% by weight

Component (A) Component of Thermoplastic Resin Composition: Ethylene-Unsaturated Organic Acid Copolymer The ethylene-unsaturated organic acid copolymer constituting one component of the thermoplastic resin composition of the present invention is It is a copolymer obtained by copolymerizing ethylene and unsaturated organic acids (hereinafter, may be simply referred to as "copolymer"). The copolymer here includes a random copolymer, a block copolymer and a graft copolymer. In addition, the unsaturated organic acid may be one kind or two.
A mixture of two or more species can be used.

The unsaturated organic acid copolymerizable with ethylene is an unsaturated organic acid such as acrylic acid, methacrylic acid, fumaric acid, maleic acid or itaconic acid and its anhydride, or its half ester or metal salt. The content of unsaturated organic acid in the copolymer is 5 to 15% by weight, preferably 6 to 13% by weight, and particularly preferably 7 to 11% by weight. If it is less than 5% by weight, the adhesive strength to the aluminum foil base material is not sufficient, and the heat seal strength to the polyethylene base material is too strong, so that peeling becomes difficult. On the other hand, 15
If it exceeds 5% by weight, the heat resistance of the thermoplastic resin composition is lowered, and the thermoplastic resin composition may be unsealed at the time of boiling the retort pouch, which is not preferable.

The copolymer melt flow rate (MFR; 190 ° C., 2.16 k) in accordance with JIS K6730.
g load) is preferably 1 to 10 from the viewpoint of moldability.
It is 0 g / 10 minutes, preferably 2 to 50 g / 10 minutes.
Specific examples of the copolymer include ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid-ethyl acrylate copolymer, ethylene-acrylic acid-butyl acrylate copolymer, ethylene- Examples thereof include methacrylic acid-methyl methacrylate copolymer, maleic anhydride grafted polyethylene, and ethylene-methyl acrylate copolymer grafted with maleic anhydride. Among them, ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer are preferable from the viewpoint of adhesiveness to an aluminum foil base material and heat sealability to a paper / polyethylene base material.

Component (B): Modified Copolymer The modified copolymer constituting one component of the thermoplastic resin composition is an ethylene-unsaturated organic acid copolymer (b1) used as the modifying resin particles. A modified copolymer obtained by subjecting the vinyl monomer (b2) to a graft reaction condition. In subjecting the above ethylene-unsaturated organic acid copolymer (b1) and vinyl monomer (b2) to graft reaction conditions,
The following radical generators are usually used except for the reaction by radiation. Raw materials for the modified copolymer and a method for producing the modified copolymer will be described below.

(A) Raw material (b1) of modified copolymer: ethylene-unsaturated organic acid copolymer The ethylene-unsaturated organic acid copolymer is compatible with the above-mentioned component (A) from the viewpoint of compatibility. The same is preferable. That is, it is a random copolymer, a block copolymer or a graft copolymer of ethylene and an unsaturated organic acid, and an ethylene-acrylic acid copolymer and an ethylene-methacrylic acid copolymer are preferable.

The content of unsaturated organic acid in the copolymer is 5 to 15% by weight, preferably 6 to 13% by weight, particularly preferably 7 to 11% by weight. If it is less than 5% by weight, the adhesive force to the aluminum foil substrate is not sufficient,
In addition, the heat seal strength against the polyethylene base material is too high and peeling becomes difficult, which is not preferable. On the other hand, 15% by weight
If it exceeds the range, the heat resistance of the thermoplastic resin composition of the present invention decreases, which is not preferable. In addition, if the content of the unsaturated organic acid in the copolymer is within the above range, the content may be different from the content of the unsaturated organic acid in the copolymer according to the component (A).

(B2) Specific examples of the vinyl monomer used in producing the modified vinyl monomer copolymer include styrene, 2-methylstyrene and 3
-Unsaturated aromatic monomers such as methylstyrene, 4-methylstyrene, dimethylstyrene, chlorostyrene; vinyl esters such as vinyl acetate and vinyl propionate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, Acrylic esters such as t-butyl acrylate, sec-butyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, hexyl acrylate, octyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate. , Decyl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, and other methacrylic acid esters; acrylic acid, methacryl Unsaturated organic acids such as maleic anhydride, dimethyl maleate and di (2-ethylhexyl) maleate; unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated mono- or dihalides such as vinyl chloride and vinylidene chloride. Can be mentioned. Among them, styrene or methyl methacrylate, particularly styrene is preferable because it can be easily modified.

(B3) Radical generator As the radical generator used in producing the modified copolymer, a general-purpose radical generator can be used.
In view of the preferable graft reaction method described later, those having a decomposition temperature of 50 ° C. or higher and being oil-soluble are preferable. Those having a decomposition temperature of 60 to 120 ° C. are preferable. Here, the "decomposition temperature" means that the decomposition rate of the radical generator is 5 when left standing for 10 hours at a temperature in which 0.1 mol of the radical generator is added to 1 liter of benzene.
It is the temperature when it reaches 0%. The so-called "decomposition temperature for obtaining a half-life of 10 hours" is meant. If a polymer having a low decomposition temperature is used, the polymerization of the vinyl monomer may progress abnormally, and there is a drawback that a homogeneous modified polymer cannot be obtained.

Examples of such a radical generator include 2,4-dichlorobenzoyl peroxide, t-butylperoxypivalate, o-methylbenzoyl peroxide, bis-3,5,5-trimethylhexanoyl peroxide. , Octanoyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, cyclohexanone peroxide, 2,5-dimethyl-2,5-dibenzoylperoxyphene, t-butylperoxybenzoate, The-t-
Organic peroxides such as butyl-diperoxyphthalate, methyl ethyl ketone peroxide, dicumyl peroxide, di-t-butyl peroxide; azo such as azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) There are compounds, etc.

It is also possible to perform a graft reaction efficiently by performing a stepwise or continuous decomposition by appropriately combining those having a high decomposition temperature and those having a low decomposition temperature. The amount of the radical generator used is 0.01 to 1 with respect to the amount of the vinyl monomer used.
Within the range of about 0% by weight, the amount may be appropriately adjusted depending on the type of radical generator and reaction conditions. If the amount used is less than this amount, the reaction does not proceed smoothly. On the other hand, if the amount used exceeds this amount, gel is likely to be formed in the modified copolymer, and the effect of the present invention is difficult to be exhibited.

(A) Production of modified copolymer A modified copolymer is produced by subjecting each of these raw material components to a graft polymerization reaction. It should be produced by the aqueous suspension graft method described below. Is a particularly preferable method because it is easy to control the gel content. That is, first, in an impregnation step, an aqueous suspension containing a particulate ethylene-unsaturated organic acid copolymer (b1), a vinyl monomer (b2) and a radical generator (b3) is added to the radical generator (b3). Is raised to a temperature at which decomposition of
After impregnating the particulate ethylene copolymer (b1) with the vinyl monomer (b2), the aqueous suspension is further heated in a graft polymerization step to further increase the temperature of the vinyl monomer (b2). The method of completing the polymerization of is preferable, and this method will be described.

[Impregnation Step] The particulate ethylene-unsaturated organic acid copolymer (b1) is added to the vinyl monomer (b) in an aqueous medium.
As a typical preferable method of impregnating with 2), an aqueous suspension containing the particulate ethylene-unsaturated organic acid copolymer (b1) is preferably a radical generator (b3) (and, if necessary, Vinyl monomer (b2) in which other additives are dissolved is added and stirred, or particulate ethylene is added to an aqueous dispersion of vinyl monomer (b2) in which radical generator (b3) is dissolved. Start by the method of adding the unsaturated organic acid copolymer (b1) and stirring.

In the impregnation step, industrially, the temperature should be raised to a temperature at which the radical generator (b3) is not substantially decomposed and the impregnation should be carried out efficiently.
It is preferred to operate at 0 ° C, especially 60-90 ° C. In this impregnation step, the vinyl monomer (b2) is impregnated so that the amount of the free vinyl monomer is 80% by weight or less of the amount of the supplied vinyl monomer.

Ethylene-unsaturated organic acid copolymer (b1)
Is relatively compatible with the vinyl monomer (b2), even if 80% by weight or less of the vinyl monomer is liberated before the initiation of the polymerization, these vinyl monomers may be particulate ethylene-containing during the polymerization process. Since the unsaturated organic acid copolymer (b1) is impregnated, a vinyl monomer polymer is prepared separately from the particulate modified polymer (B) obtained by graft-polymerizing the vinyl monomer (b2). It does not precipitate independently. The impregnation time is usually about 2 to 8 hours.

The content of the ethylene-unsaturated organic acid copolymer (b1) and the vinyl monomer (b2) in the aqueous dispersion is usually about 5 to 100 parts by weight based on 100 parts by weight of water. Is. Such an aqueous dispersion can be stably maintained in a dispersed state by simply performing sufficient stirring, but it is easier and more stable to prepare the suspension dispersion by using an appropriate suspension stabilizer. You can

Examples of the suspension stabilizer in this case include water-soluble polymers such as polyvinyl alcohol, methyl cellulose and hydroxy cellulose; anionic surfactants such as alkylbenzene sulfonate; nonionics such as polyoxyethylene alkyl ether. Water-soluble surfactant; or water-insoluble inorganic salt such as magnesium oxide, calcium phosphate, etc., alone or in a mixture of 0.01 to water.
It is used in an amount of about 10 to 10% by weight.

When the particulate ethylene-unsaturated organic acid copolymer (b1) is impregnated with the vinyl monomer (b2) (and a radical generator etc.), an auxiliary material such as a plasticizer, a lubricant or an antioxidant. Can be impregnated at the same time (these auxiliary materials may already be added to a commercially available ethylene-unsaturated organic acid copolymer, or can be added after the graft polymerization reaction).

[Graft Polymerization Step] If the temperature of the aqueous suspension thus prepared is raised to a temperature above the temperature at which the used radical generator (b3) decomposes at an appropriate rate, the impregnated vinyl monomer will be treated. The monomer (b2) is graft-polymerized with the ethylene-unsaturated organic acid copolymer (b1) to produce a modified copolymer (B). It is preferable to appropriately stir the aqueous suspension during the graft polymerization. The polymerization temperature should generally be appropriately selected within the range of 50 to 150 ° C., but need not be constant throughout the graft polymerization process. The polymerization is usually about 2 to 10 hours. The polymerization pressure is usually atmospheric pressure to about 10 kg / cm ² .

After the polymerization, the same post-treatment as the usual post-treatment of aqueous suspension polymerization of vinyl monomer (for example, styrene) is carried out to obtain the particulate ethylene-unsaturated organic acid copolymer (b1) used. A particulate modified copolymer can be obtained which has a shape almost unchanged and can be immediately used as a molding material. The particle size is preferably such that it is generally used as a molding material because the modified copolymer produced can be directly used as a molding material, and generally the average particle size is 1 to 8 mm, preferably 3 to It is about 7 mm. The size does not change significantly before and after the modification treatment.

Blending Ratio of Thermoplastic Resin Composition The blending ratio of the thermoplastic resin composition is 1 to 90% by weight of the ethylene-unsaturated organic acid copolymer as the component (A),
The modified copolymer as the component (B) is 99 to 10% by weight. Preferably, the component (A) is 10 to 90% by weight (B)
The component is 90 to 10% by weight, particularly preferably the component (A) is 20 to 85% by weight and the component (B) is 80 to 15% by weight. When the blending ratio of the component (B) is less than 10% by weight, it is insufficient to obtain heat seal strength for the aluminum foil. On the other hand, if the blending ratio of the component (B) exceeds 99% by weight, moldability is deteriorated, which is not preferable.

[0031] The additional component thermoplastic resin composition contains the above-mentioned components (A) and (B) as main components, but in addition to these essential components, additional components are added in amounts that do not impair the effects of the invention. It can be added. As the additional component, for example, another thermoplastic resin,
Examples include rubber substances, inorganic fillers, pigments, plasticizers, various stabilizers (antioxidants, antistatic agents, light stabilizers, antiblocking agents, lubricants) and the like.

(II) Structure of Lid Material The lid material of the present invention contains the thermoplastic resin composition in an amount of 7 to 7
It can be manufactured by extrusion lamination molding with a thickness of 10 to 30 μm on a 50 μm aluminum foil substrate. The lid material of the present invention comprises two layers of a thermoplastic resin composition layer / aluminum layer as a basic constituent layer, and is composed of three or more layers including other layers (for example, a polyethylene terephthalate layer). / Aluminum layer / thermoplastic resin composition layer).

(III) Main Body of Packaging Container The base material of the main body of the container is a pulp having a normal basis weight of 100.
10 ~ 25 polyethylene on ~ 500g / m ² paper
Polyethylene layer coated with a thickness of μm (11)
/ Based on a two-layer sheet of paper layer (12).
Of course, the container may include other layers. The container body is obtained by molding such a sheet into the shape of a container having an opening.

(IV) Container for packaging After the container body (1) is filled with liquid or solid beverages, foods such as dairy products, pharmaceuticals, etc., the opening provided in the container body is provided with the lid member (2). ), The packaging container is formed. The sealing with the lid material is performed by heat-sealing (thermally adhering) the thermoplastic resin composition layer (21) of the lid material and the polyethylene layer (11) of the container body.

The heat sealing time is usually 0.1 to 2 minutes, preferably 0.2 to 1 minute, and the heat sealing temperature is usually 90 to 160 ° C., preferably 100 to 100 ° C.
It is 130 ° C. The packaging container thus obtained has the following features. That is, since the thermoplastic resin composition layer (21) made of a specific component is provided on the lid material, it can be easily peeled off after being heat-sealed with the polyethylene layer (11) constituting the container body, and The peel strength (p) between the layer (11) and the layer (21) was calculated as follows:
Since it is relatively lower than the peel strength (p1) between 2), it does not damage the paper when the consumer peels off the lid material to take out the contents at the time of opening, and not only has an excellent appearance. Also, it is possible to prevent the pieces of paper from mixing with the contents.
The peel strength (p) between the layer (11) and the layer (12) is adjusted by the unsaturated organic acid content in the ethylene-unsaturated organic acid copolymer.

[0036]

【Example】

[Example 1] Step of producing modified particulate copolymer An autoclave having a volume of 50 liters was mixed with 20 kg of water, 0.6 kg of tricalcium phosphate as a suspending agent, and 0.6 g of sodium dodecylbenzenesulfonate, and an aqueous medium. And an ethylene-acrylic acid copolymer having a particle size of 3 to 4 mm (Mitsubishi Polyethylene-EAA; acrylic acid content:
8.5 wt%, MFR: 7 g / 10 min) 6 kg,
Stir to suspend. Separately, 130.2 g of t-butyl peroxypivalate and benzoyl peroxide 4
0.2 g of styrene was dissolved in 6 kg of styrene, this was added to the above suspension system, and nitrogen was introduced into the autoclave to pressurize the system to 0.5 kg / cm ² . Further, the temperature inside the autoclave was raised to 50 ° C., and the mixture was allowed to stand for 5 hours while stirring at this temperature to impregnate the whole amount of styrene containing a polymerization initiator into the low density polyethylene particles. Next, this suspension was heated to 60 ° C., and allowed to stand for 5 hours while stirring at this temperature to polymerize styrene, and further heated to 85 ° C. and maintained for 3 hours to complete the polymerization. After cooling, take out the solid contents and wash with water,
Particulate styrene-modified ethylene-acrylic acid copolymer 1
2 kg was obtained. The MFR of the obtained styrene-modified ethylene-acrylic acid copolymer was 2 g / 10 minutes.

Production of Thermoplastic Resin Composition Ethylene-acrylic acid copolymer (Mitsubishi Polyethylene-EA
A: Acrylic acid content: 8.5% by weight, MFR: 7 g / 1
0 minutes) 55% by weight, 45% by weight of the styrene-modified ethylene-acrylic acid copolymer obtained in the above production process are mixed,
Using a single screw extruder (L / D = 23), resin temperature 180 ° C
Were melt-mixed with each other, extruded in a strand form from a die, and cut into pellets (MFR: 6 g / 10 min).

Manufacture of Lid Material Obtained above with respect to the aluminum layer surface of a three-layer laminate made of polyethylene terephthalate (thickness 12 μm) / polyethylene (thickness 20 μm) / aluminum foil (thickness 7 μm) prepared in advance. Using a 40 mm diameter extruder, pellets of the thermoplastic resin composition were extruded and laminated to a coating thickness of 25 μm from a T die under conditions where the resin temperature at the die exit was 280 ° C., and laminated lid material consisting of 4 layers. Was manufactured.

The layer of the thermoplastic resin composition of the laminated lid material is used as an adhesive surface, and the paper (base weight 25
It was heat-sealed with a polyethylene layer of a two-layer laminate consisting of 0 g / m ² ) / polyethylene (thickness 15 μm). The heat-sealing conditions were as follows: using a hot plate heat sealer, the adhesive surface was 5 mm wide, the adhesive pressure was 2 kg / cm ² , the time was 0.5 seconds,
Heat seal temperatures are 140 ° C, 150 ° C and 160 ° C.

Evaluation (a) The adhesive strength with the aluminum foil was measured using an Instron type tensile tester with a sample width of 15 mm and a pulling speed of 30.
The 180 degree peel strength at 0 mm / min was measured at 23 ° C. The results are shown in Table-1. (B) Peel strength was measured using an Instron type tensile tester,
180 at a sample width of 15 mm and a pulling speed of 300 mm / min
Peel strength was measured at 23 ° C. The results are shown in Table-1. (C) The peeling interface was evaluated as good if it could be peeled without damaging the adherend substrate, and as bad otherwise. (D) Heat resistance is measured by measuring peel strength in an atmosphere of 80 ° C.
Those having a peel strength of 100 g / 15 mm width or more were evaluated as good, and those having a peel strength of less than 100 g / 15 mm width were evaluated as poor.

[Examples 2 to 4] The thermoplastic resin compositions shown in Table 1 were evaluated in the same manner as in Example 1. In Example 2 and Example 3, thermoplastic resin compositions were produced by changing the compounding ratio of the styrene-modified ethylene-acrylic acid copolymer and the ethylene-acrylic acid copolymer in Example 1. Further, in Example 4, 65% by weight of a styrene-modified ethylene-acrylic acid copolymer and an ethylene-acrylic acid copolymer (Mitsubishi Polyethylene-EAA; acrylic acid content: 8.5% by weight, MFR: 20 g / 10 minutes). A thermoplastic resin composition was produced under the same conditions as in Example 1 except that 35% by weight was mixed. The results are shown in Table-1.

Comparative Example 1 Evaluation was made in the same manner as in Example 1 except that the modified ethylene-acrylic acid copolymer was not used but only the ethylene-acrylic acid copolymer was used. The results are shown in Table-1.

[Comparative Example 2] Instead of the ethylene-acrylic acid copolymer of Example 1, low density polyethylene (MF) was used.
Evaluation was performed in the same manner as in Example 1 except that R: 14 g / 10 min, density: 0.918 g / cm ³ ) was used. The results are shown in Table-1.

Comparative Example 3 In the production of the styrene-modified ethylene-acrylic acid copolymer of Example 1, an ethylene-acrylic acid copolymer (MF having an acrylic acid content of 4% by weight) was prepared.
R: 5 g / 10 min) as a reforming raw material to produce a styrene-modified ethylene-acrylic acid copolymer, wherein the acrylic acid content is 4% by weight ethylene-acrylic acid copolymer (MFR: 5 g / 10 Min) to obtain a thermoplastic resin composition, which was evaluated in the same manner as in Example 1. The results are shown in Table-1
Shown in.

Comparative Example 4 In the production of the styrene-modified ethylene-acrylic acid copolymer of Example 1, an ethylene-acrylic acid copolymer (MF having an acrylic acid content of 17% by weight) was used.
R: 25 g / 10 minutes) as a reforming raw material to produce a styrene-modified ethylene-acrylic acid copolymer, and an ethylene-acrylic acid copolymer having an acrylic acid content of 17% by weight (MFR: 25 g / 10 Min) to obtain a thermoplastic resin composition, which was evaluated in the same manner as in Example 1. The results are shown in Table-1.

[0046]

[Table 1]

[0047]

EFFECT OF THE INVENTION The lid material of the present invention has excellent adhesiveness to an aluminum foil and excellent heat sealability to polyethylene of the body of the packaging container, while peeling (opening) the lid material from the packaging container. The container and the sheet can be easily opened without damage, and the lid and the packaging container using the lid are extremely practical.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI B65D 77/20 B65D 77/20 L C08L 51/06 C08L 51/06 (56) Reference JP-A-56-88481 (JP, A ) JP-A-58-30956 (JP, A) JP-A-8-217147 (JP, A) Actually open 59-51723 (JP, U) Actually open 60-41237 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 B65D 3/26 B65D 77/20 C08L 1/00-101/14

Claims (4)

(57) [Claims] 1. A lid material for a packaging container, wherein a layer comprising a thermoplastic resin composition comprising the following components (A) and (B) as a base material is laminated on an aluminum layer. Component (A): ethylene-unsaturated organic acid copolymer having an unsaturated organic acid content of 5 to 15% by weight 1-90% by weight (B) component: unsaturated organic acid content of 5 to 15% Modified copolymer obtained by subjecting ethylene-unsaturated organic acid copolymer (b1) of 30 to 95% by weight and vinyl monomer (b2) of 70 to 5% by weight to graft reaction conditions. 99-10% by weight 2. The modified copolymer (B) comprises a particulate ethylene-unsaturated organic acid copolymer (b1) and a vinyl monomer (b).
The aqueous suspension containing 2) and the radical generator is heated to a temperature at which decomposition of the radical generator does not substantially occur, and the vinyl monomer (b2) is added to the particulate ethylene-unsaturated organic acid. After the impregnation with the copolymer (b1), the aqueous suspension was further heated to a temperature not lower than the decomposition temperature of the radical generator to complete the graft reaction of polymerizing the vinyl monomer. The lid material according to claim 1, which is a thing. 3. A packaging container body (1) having an opening.
And a lid member (2) for sealing the opening, the container body (1) comprises a polyethylene layer (11) and a paper layer (1).
A layer (21) comprising a thermoplastic resin composition as a base material, wherein the lid material (2) is composed of the following components (A) and (B) And a polyethylene layer (22), and a polyethylene layer (11) of the container body (1) and a thermoplastic resin composition layer (21) of the lid member (2). A packaging container having a structure in which the opening of the container body is sealed by heat sealing, and the polyethylene layer (11) and the thermoplastic resin composition layer (21) can be easily separated when opened. Component (A): ethylene-unsaturated organic acid copolymer having an unsaturated organic acid content of 5 to 15% by weight 1-90% by weight (B) component: unsaturated organic acid content of 5 to 15% Modified copolymer obtained by subjecting ethylene-unsaturated organic acid copolymer (b1) of 30 to 95% by weight and vinyl monomer (b2) of 70 to 5% by weight to graft reaction conditions. 99-10% by weight 4. The peel strength (p) between the polyethylene layer (11) and the thermoplastic resin composition layer (21) adhered by heat sealing is such that the polyethylene layer (11) and the paper layer (1)
The packaging container according to claim 3, which is relatively lower than the peel strength (p1) between 2).