JPS6135943B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a retort food packaging that uses a polyolefin resin blended with polyolefin, α/β-ethylenically unsaturated carboxylic acid, and a metal compound, and has excellent barrier properties, pressure resistance, etc., and also has excellent adhesive strength after retort sterilization. The present invention also relates to a method for manufacturing containers used for beverages, etc. In general, the basic properties required for food packaging materials are (1) materials with good hygiene, (2) good barrier properties, (3) good light blocking properties, (4)
It has high mechanical strength, (5) it is resistant to moisture, acids, and alkalis, and (6) it can be manufactured in a short time. In addition to the above, materials that are sterilized by retort must also (1) have good heat resistance (100 to 140℃);
(2) It is required that there is no decrease in adhesive strength even if it contains contents. Therefore, it is impossible to meet these various requirements with a single plastic or other material, and composite films or composite materials are used as food packaging materials. These materials include polyolefin, polyamide, polyester, aluminum, etc., but aluminum foil, which has particularly excellent barrier properties, and polyolefin film, which has excellent hygiene, are often used as food packaging materials for retort pouches. Polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, and polybutene have excellent hygiene properties and are therefore useful resins for food packaging materials. It is well known that there is almost no adhesion to the base material, making it difficult to use. In order to improve this point, efforts have been made to chemically and physically treat these polyolefins and to utilize energy such as ultraviolet rays and electron beams. However, in reality, very low adhesion strength can be obtained, or even if it can be obtained, it takes time to heat and dry, pressure must be applied, and there are cases where a brimer is used to promote adhesion. many. There are few examples of methods of modifying or modifying polyolefin itself to make it highly adhesive. In fact, polyurethane resins and the like are often used as adhesives when high adhesive strength is required between polyolefin films and other base materials. However, polyurethane resin adhesives are said to have the following drawbacks. (1) There is a possibility that unreacted substances or low-molecular substances of the raw material polyisocyanate or polyol may be transferred to food contents, which poses a hygiene problem. Therefore, it is not preferable to use it inside a layer with excellent barrier properties. (2) When considering the adhesive strength between base materials such as metal or plastic film used as packaging materials, heating treatment at 50 to 60°C for about one week at room temperature is necessary to obtain adhesive strength that can withstand actual use. However, it is necessary to mature it on a daily basis. (3) When adhering polyolefin to other base materials, foaming is observed in the adhesive area, causing variations in adhesive strength and reducing commercial value. Despite these drawbacks, the current situation is that there is currently no practical adhesive for polyolefins other than polyurethane resins. It is also known that metal ion crosslinked polyolefin resins are used for laminating substrates in applications such as building materials and packaging materials. This metal ion-crosslinked polyolefin resin is considered to be a type of thermoplastic resin (ionomer) in which long chain molecules are connected by ionic bonds, and its structure consists of monovalent or polyvalent metal cations and long chain molecules. It generates ionic bonds between long chain molecules via carboxyl groups. Conventional compositions and uses of ionomers include US Pat.
-27580, JP-A-58-74583, etc. For example, Surlyn (manufactured by DuPont, USA) is used as a food packaging material for retort pouches, and dry lamination is performed using a polyurethane resin adhesive to laminate films containing an ionomer. Traditionally, thick-walled polyolefin containers have been made by blow molding, but all of them are transparent.
Although they have the advantage of being able to see the contents and being able to stand on their own as a container, they are not sufficient in terms of storage stability and gas barrier properties, and thick round-bottomed containers made as pressure-resistant containers also have the same drawbacks. Therefore, in order to improve the barrier properties, it is possible to use aluminum foil, which is a material with excellent barrier properties, in combination.
As mentioned above, polyolefin has poor adhesion to other materials, and although polyurethane resin adhesives are used, this leaves problems with hygiene. Furthermore, in the case of metal cans, an inner surface paint is required, and there are problems in workability, such as the need to repair the inner surface coating film that has been damaged by the wrapping during molding. The present invention addresses the above-mentioned problems and improves hygiene.
The present invention provides a method for producing a container that has excellent barrier properties and can also be used as a pressure-resistant container for retort sterilization. In other words, this is a container manufacturing method in which the following (), (), or () is performed on the outer surface of a thick-walled cylindrical object made of polyolefin, and then () is performed. () A lamination of a polyolefin resin in which an α/β-ethylenically unsaturated carboxylic acid and a metal compound are heat-blended with a polyolefin, or a polyolefin resin in which at least an α/β-ethylenically unsaturated carboxylic acid is graft-polymerized to the polyolefin, and aluminum foil. While heat-sealing the film to a cylindrical object with the polyolefin resin as the inner surface, the film is wound spirally over the entire surface, and then an adhesive and one type selected from polyolefin film, polyester film, polyamide film, and polyolefin processed paper are applied on top of the film. Wrap the laminated film in a spiral over the entire surface with adhesive as the inner surface. () A laminated film of the polyolefin resin and aluminum foil is wound spirally around the entire surface of a cylindrical object with the polyolefin resin as the inner surface while heat-sealing it, and an adhesive is coated thereon, and then a polyolefin film is formed. One type selected from polyester film, polyamide film, and polyolefin processed paper is laminated. () The polyolefin resin, aluminum foil, adhesive, and polyolefin film,
A laminated film made of one type of film selected from polyester film, polyamide film, and polyolefin-processed paper is spirally wound over the entire surface while being thermally fused with polyolefin resin as the inner surface. () A polyolefin sheet or film, the polyolefin resin, aluminum foil, an adhesive, and a polyolefin film,
Top and bottom lids made of one selected from polyester film, polyamide film, and polyolefin-treated paper are respectively adhered to the cylindrical object on which (), (), or () has been applied. The thick-walled cylindrical object made of polyolefin related to the present invention is a cylindrical object made of polyolefin such as polyethylene, polypropylene, polybutene, etc., and usually has a thickness of 0.1 to 3 mm, and the pressure-resistant container is a cylindrical object of about 1 to 3 mm. It is a cylindrical object in the shape of a cylinder, square tube, hexagonal tube, etc. This cylindrical article can be obtained by injection molding, extrusion molding, blow molding, or the like. Also 100~300μ
A thick polyolefin film formed into a cylindrical object may also be used. Furthermore, it may be made by laminating polyolefin films. The polyolefin of the cylindrical material may contain additives within a range that does not cause hygienic problems. In addition, when the container of the present invention is used as a retort food container, a cylindrical object using a polyolefin having excellent heat resistance such as high-density polyethylene or polypropylene is used as the polyolefin. The polyolefin resin according to the present invention is a resin in which an α-β ethylenically unsaturated carboxylic acid and a metal compound are heat blended with a polyolefin, or at least an α/β-ethylenically unsaturated carboxylic acid is graft-polymerized with the polyolefin. be. The polyolefin may be polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, etc., and may be a product mainly composed of olefin and copolymerized with other copolymerizable monomers. In addition, when used in retort food packaging materials, heat-resistant polyolefins such as high-density polyethylene produced by a low-pressure method, copolymers of ethylene and propylene produced by a low-pressure method, and high-density polyethylene produced by a medium-pressure method are used. It is preferable to use highly crystalline materials such as copolymers of ethylene and propylene produced by a medium pressure method, isotactic and syndiotactic polypropylenes having stereoregularity. As the α/β-ethylenically unsaturated carboxylic acid, one or more of acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, maleic anhydride, etc. can be used. This α/β-ethylenically unsaturated carboxylic acid is used in an amount of 0.01 to 30 parts by weight per 100 parts by weight of the polyolefin. If the amount is less than 0.01 parts by weight, the effect on adhesion will be weak, and on the contrary, if it is more than 30 parts by weight, no improvement in the effect on adhesion will be observed. Metal compounds include carbonates, sulfates, acetates of sodium, potassium, magnesium, calcium, zinc, iron, aluminum, copper, nickel, etc.
Oxides, hydroxides, organic compounds, etc. are used. Note that metal compounds of magnesium, calcium, and aluminum are preferred for food-related fields.
The metal compound is based on 100 parts by weight of polyolefin.
It is blended in an amount of 0.05 to 10 parts by weight. When used within this range, it exhibits high adhesive strength even with short heat treatment. If less than 0.05 parts by weight is used, it is difficult to obtain high adhesive strength with a short heat treatment, and conversely, if more than 10 parts by weight is added, not only is no improvement in adhesive strength observed, but the polyolefin resin will foam when heated and melted. This is inappropriate because it causes problems such as the inability to apply the coating uniformly to the substrate. When synthesizing the polyolefin resin according to the present invention by heat compounding, it is also possible to use a third component such as polybutadiene. However, it is necessary to select a third component that does not adversely affect adhesive properties. The polyolefin resin according to the present invention can be produced by several methods, including a method of mixing together with a heating operation as shown below. Preferred are the various methods shown below. In addition, the polyolefin for polyolefin resin is (A), α・β-
Ethylenically unsaturated carboxylic acid (B), metal compound
Expressed as (C). (1) A method of adding and blending (C) to a heated mixture of (A) and (B), (2) A method of adding and blending (B) to a heated mixture of (A) and (C), (3) (4) A method of mixing three substances (A), (B), and (C) at the same time and heating them. However, the order of addition and blending is not limited to this, and in addition to heating and mixing, reactions using other energy sources are also possible. The polyolefin resin of the present invention can be easily produced by the various methods described above. Furthermore, the above four methods can be carried out by two methods: a melt method and a solvent method. For example, when method (1) is carried out by the melting method, polyolefin (A) and α/β-ethylenically unsaturated carboxylic acid (B) are mixed using a hot roll or an extruder to form polyolefin (A). 10℃ from the softening point of
Melt and mix at a temperature higher than 100°C. Although it is desirable to adjust the melt mixing time depending on the type of polyolefin (A), 5 to 90 minutes is usually sufficient. Furthermore, a metal compound (C) is added to this molten mixture.
Add and mix. The method of adding the metal compound (C) is as follows:
If the particle size is small (for example, about 1 μm or less), it may be added as is, but it is necessary to take measures to mix it as uniformly as possible. On the other hand, regarding the solvent method, this method is advantageous when removing unreacted substances or when it is necessary to avoid coloring of the resin. As a solvent, aromatic hydrocarbons such as toluene, xylene and Solbetsuso (Etsuso) can generally be used. For example, by adding and mixing a predetermined amount of the above (A) and (B) to xylene, the polyolefin (A) and α/β-ethylenically unsaturated carboxylic acid (B) are combined in the presence of a polymerization initiator such as benzoyl peroxide (BPO). Graft polymerization is performed. In the presence of the above benzoyl peroxide (A) and
When heating the mixture of (B), instead of adding the entire amount of α/β-ethylenically unsaturated carboxylic acid (B) at once, there is also a method of adding it little by little. There is little generation, and the adhesiveness of the polyolefin resin finally obtained is good. The heating and mixing can be carried out at 130 to 134°C for 30 minutes to 3 hours. It is desirable to thoroughly wash the graft polymer of (A) and (B). Further, the metal compound (C) is added and mixed, and heated for 15 to 60 minutes. In this case as well, it is desirable to swell and disperse the metal compound (C) in advance with a small amount of methanol, acetone, water, etc., and then uniformly mix it into the resin solution. The polyolefin resin is required to have strict hygienic properties when the container of the present invention is used in food-related applications. Therefore, it is desirable to thoroughly wash the polyolefin resin with acetone, methyl ethyl ketone, ethyl acetate, etc. during or after the synthesis, and the polyolefin resin obtained by washing has excellent adhesive properties. It indicates the nature. As mentioned above, α/β-ethylenically unsaturated carboxylic acid (B) is 0.01 to 100 parts by weight of polyolefin (A).
Heat compounding is performed using 30 parts by weight and 0.05 to 10 parts by weight of the metal compound (C), and the resulting polyolefin resin contains approximately 0.01 to several weight% of α/β-ethylenically unsaturated carboxylic acid (B). Since it is graft polymerized, unreacted (B) or its addition polymerization product adversely affects adhesion, so it is desirable to remove it sufficiently. Moreover, the metal compound (C) is not necessarily crosslinked to all of the grafted α/β-ethylenically unsaturated carboxylic acids. In addition, in the present invention, polyolefin resins made of polyethylene as a base resin can be used for general packaging materials, etc., but polyolefin resins made of polyethylene, especially low-density polyethylene as a base resin, have poor retort resistance. etc., and when encapsulated with edible oil, acetic acid, etc., they will peel between the base materials. In addition, when using polypropylene for a cylindrical object, there is no heat sealing property between the polyolefin resin made of polyethylene and the polypropylene, and the adhesive strength is low, so the cylindrical object and the polyolefin of the polyolefin resin are of the same type. It is preferable to use Furthermore, for applications requiring heat resistance such as retort resistance, polyolefin resins based on high density polyethylene or polypropylene must be used. The polyolefin resin obtained as described above can be used by dissolving it in an aromatic hydrocarbon such as xylene or Solbetsuso (Etsuso), or it can be laminated directly onto a base material or sandwiched between base materials using an extruder. It can be used by either method or by coating it in powder form.
Further, this polyolefin resin is used as an adhesive layer and/or a plastic film layer. The laminated film or laminate used in (), (), () or () of the present invention will be explained. The laminated film of polyolefin resin and aluminum foil () or () can be produced by coating the polyolefin resin on aluminum foil using an extruder, coating it as a paint, or overlapping polyolefin resin that has been made into a film in advance. Aluminum foil coated or laminated with polyolefin resin by the method described in (1) is heated to combine with polyolefin resin and aluminum foil by contacting with a hot roll or hot plate, passing through a heating furnace, infrared irradiation, hot air blowing, etc. (2) Use the heat of thermal fusion when wrapping these non-heat-treated laminated films around a polyolefin cylindrical object to bond polyolefin resin and aluminum foil. Either can be used to strengthen the adhesion with. By using aluminum foil, the barrier properties against oxygen gas etc. are dramatically improved, and the light resistance, water resistance, etc. are also improved. The aluminum foil used in the present invention may have a thickness of 7 to 100 microns; if it is too thin, the barrier properties will be poor, and if it is too thick, no improvement in performance can be expected and it is uneconomical. Various adhesives can be used as the adhesive in the laminated film of (1) the adhesive and one selected from polyolefin, polyester film, polyamide film, and polyolefin-processed paper.
For example, even if the container obtained according to the present invention is used for food applications, since the outer layer is aluminum foil, hygiene problems are unlikely to occur due to the adhesive.
Therefore, an adhesive such as a polyurethane resin adhesive can be used, but it is also possible to use a polyolefin resin as described above. In this case, heat fusion is required during winding, but the adhesiveness and sanitary properties are better. The laminated film in parentheses is a film made of polyolefin resin, aluminum foil, adhesive, polyolefin film, and the like. For example, the aluminum foil can be made by first laminating a polyolefin film, etc. with a polyurethane resin adhesive, a polyolefin resin adhesive, etc., and then coating or coating the aluminum foil surface with a polyolefin resin in the same way as the laminated film in (). Layer them together and heat treat if necessary. Note that the method is not limited to this method. The lid in parentheses is similar to the laminated film in parentheses, but a polyolefin sheet or film is also used. Coextrusion can also be used in some ways, for example, polyolefin and polyolefin resin, polyolefin resin and polyolefin as an adhesive,
Polyester or polyamide laminates can also be made by coextrusion. Furthermore, when the container obtained according to the present invention is used for food applications, it is preferable to use a polyolefin resin as the adhesive. Note that there are no particular restrictions on how to make it. Next, the method for manufacturing the container of the present invention will be explained.
In method (), first, a laminated film of polyolefin resin and aluminum foil is spirally wrapped around the entire surface of a polyolefin cylindrical object. In addition,
In the present invention, the entire surface also means that when the laminated films are wound in a spiral manner, the ends of the laminated films partially overlap. When this laminated film is wound, the surface of the polyolefin cylindrical object and/or the polyolefin resin of the laminated film are thermally fused and fixed. Methods for thermal fusion include ultrasonic waves, thermal sealing, and the like. Note that heat fusion must be performed for a short time. In other words, long-term processing may cause deformation of the cylindrical object. With the polyolefin resin of the present invention, strong adhesion can be obtained in a short time. Furthermore, the method of spirally winding allows for positional correction, and repair of defective parts is also easy. The treatment of both ends of the spiral winding of the laminated film around the cylindrical object (the body near the top and bottom of the container) can be corrected by cutting both ends of the cylindrical object or by rewinding the laminated film. A laminated film consisting of an adhesive and one type selected from polyolefin film, polyester film, polyamide film, and polyethylene processed paper is applied to the cylindrical object after wrapping the laminated film of polyolefin resin and aluminum foil, with the adhesive on the inner surface. Wrap it in a spiral. When using polyolefin resin as adhesive,
It is adhered by heat-sealing, and does not require heat-sealing for ordinary adhesives. The above description also applies to the method of winding the laminated film in () and (). The adhesive coating in parentheses can be applied by painting methods such as spray coating, curtain coating, or air knife coating, or by wrapping a film adhesive in a spiral shape on a laminated film of polyolefin resin and aluminum foil wrapped around a cylindrical object. Depending on the method etc.
After coating, polyolefin film, polyester film, polyamide film, or polyethylene processed paper is wound spirally or cylindrically, and the overlapping portions are laminated by heat-sealing or the like. Let's talk about (). In other words, how to attach the lid that forms the top and bottom of the container. This will be explained below with reference to the drawings. Note that the drawings are embodiments of the present invention, and the present invention is not limited only to these drawings. All drawings show cross-sectional views.
Figure 1 shows a cylindrical object obtained by injection molding or a cylindrical object punched after blow molding ().
Cylindrical body 1 treated with () or ()
shows. Fig. 2 shows a cylindrical body 2 or a thick polyolefin film which has been extruded and treated with (), (), or (), and is made into a cylindrical body.
A cylindrical body 2 that has been subjected to the treatments shown in (), (), or () is shown. I will explain about the lid which will be the top (top). This lid may or may not have an opening for taking out the contents. For example, if no outlet is provided,
A laminated film of polyolefin resin and aluminum foil is laminated on a molded polyolefin with a wall thickness of about 0.1 to 3 mm, then coated with an adhesive, and a polyolefin film, polyester film, polyamide film, or polyolefin processed paper is laminated. A lid 3 as shown in Figure 3 is used. There are no particular restrictions on how to make the laminate for the lid 3, but for use as a pressure-resistant container, the polyolefin molding that will become the inner layer usually has a wall thickness of 1 to 2 mm.
It is necessary to consider such things as using a Further, the method of forming the lid as shown in FIG. 3 may be a method of laminating and then molding. If an outlet is provided, a screw-cap type outlet, an easy-open type outlet, etc. should be provided in a part of the lid. Taking a lid with an easy-open outlet as an example, the lid is injection molded to have a portion that serves as an outlet, a thick polyolefin molded product, a laminated film of polyolefin resin and aluminum foil, an adhesive, and a polyolefin in-film. The fourth layer is laminated with laminated films such as
A lid 4 as shown in the figure is used. Next, an easy-open type outlet such as a pull tab is provided in the portion 5 which becomes the outlet. The material of this easy-open outlet is made of at least metal (aluminum, etc.) that has excellent barrier properties, hygienic properties, pressure resistance, and the like. Next, we will explain the lid, which is the bottom part.
For example, a laminated film of polyolefin resin and aluminum foil is laminated on a molded polyolefin with a wall thickness of 0.1 to 3 mm, and then coated with an adhesive.
The lids 6 and 7 (FIG. 5 or 6) are laminated with polyolefin film, polyester film, polyamide film, or polyolefin processed paper. A case will be described in which a container is manufactured using the cylindrical bodies 1, 2, the lids 3, 4, and the lids 6, 7. In FIG. 7, a lid 6 is bonded to the cylindrical body 1 while being thermally fused, and then a lid 3 is bonded to the cylindrical body 1 while being thermally fused. In the case of joining by heat fusion, it is preferable that the surfaces in contact with the cylindrical body 1 and the lids 3 and 6 are made of the same material. That is, when polyethylene is used as the cylindrical material of the cylindrical body 1, it is preferable to use polyethylene or polyethylene-processed paper as the outermost layer of the lid 6. Moreover, when a polypropylene film is used as the outermost layer of the cylindrical body 1, it is preferable to use the lid 3 using polypropylene as the inner layer of the lid 3. The cylindrical body and the lid are preferably bonded by heat fusion, but they may be bonded using polyolefin resin or other adhesive. FIG. 8 shows a cylindrical body 2 with lids 4 and 7 bonded together. The lid 4 is provided with an easy-open outlet 8. In the container manufacturing method of the present invention, a thick-walled polyolefin molded cylindrical object is used, so the pressure resistance and
A container that is excellent in hygiene and also has excellent barrier properties because aluminum foil is used can be obtained. In addition, since polyolefin resin is used,
Since strong adhesive strength can be obtained by short-time heat treatment, there are no problems such as deformation caused by long-time heat treatment. The outermost layer uses polyolefin film, polyester film, polyamide film, and polyolefin-treated paper, so it has high tensile strength, impact strength,
This results in a container with excellent tensile strength. Next, examples will be shown. In the examples, "parts" indicate parts by weight. Example 1 20 parts of maleic anhydride and 375 parts of xylene were added to 100 parts of polypropylene (M value 10) through a nitrogen inlet,
Pour into a three-necked flask equipped with a thermometer and a stirring bar, and heat to 130°C while stirring in a nitrogen gas atmosphere.
Heat to. 0.1 part of benzoyl peroxide is dissolved in 40 parts of xylene and added dropwise over 90 minutes. After completing the dropwise addition, continue heating and stirring at 130°C for 60 minutes. After 60 minutes, cool to room temperature. The resulting suspension was filtered;
After xylene is removed, washing with methyl ethyl ketone is repeated two or three times, and washing is continued until almost no maleic anhydride or maleic anhydride reactant alone is observed in methyl ethyl ketone by liquid chromatography. After air-drying the obtained powder of polypropylene-maleic anhydride copolymer resin (maleic anhydride grafting rate: 0.6%), 6.5 parts of aluminum hydroxide was mixed, and using an extruder, 180 Polyolefin resin pellets obtained by melt-mixing at
240℃, resin temperature 210℃) to create a 10μ film. This film is laminated on 9μ aluminum foil using a laminator (190°C) to make a laminated film. While heating the laminated film with ultrasonic waves around a polypropylene cylinder having a wall thickness of 2 mm obtained by injection molding, the laminated film is spirally wound over the entire surface of the cylinder. Next, the laminated film obtained by bonding a polyolefin resin film (10μ) and a 100μ nylon film with a laminator (190°C) was heated with ultrasonic waves, with the polyolefin resin film facing inside, to form a cylindrical shape. It was wrapped spirally over the entire surface of an aluminum foil wrapped around an object, and both ends were cut to form a cylindrical body. Next, the top and bottom lids are fused to the cylindrical body using the same polyolefin resin using a thermal seal (a method of melting and fusing the joints with something like a welding rod). At this time, the top and bottom lids are composed of a laminated film made by laminating a 100μ nylon film and a 9μ aluminum foil with the same polyolefin resin in a laminator (190℃), and a 2mm thick polypropylene molded sheet. This was obtained by ultrasonic bonding using the same polyolefin resin. The peel strength (90° peel) of the joint between the cylindrical body and the lid of the obtained container was 2 kg/cm. Furthermore, other tests are shown in Table 1. Example 2 Example 1 was placed on the aluminum foil of a cylindrical object wrapped with a laminated film of a polyolefin resin film and aluminum foil in the same manner as in Example 1.
While heating and melting the same 10μ polyolefin resin film, a 100μ polypropylene film was attached. A 2 mm thick polypropylene sheet made according to Example 1 was placed on the obtained cylindrical body,
A top and bottom made of polyolefin resin, aluminum foil, polyolefin resin, and 100 μm polypropylene film were joined to the cylindrical body by a thermal sealing method. The peel strength of the joint between the cylindrical body and the lid of the obtained container was 1.5 Kg/cm. Other tests are shown in Table 1. Example 3 A 100μ polyethylene coated paper was adhered to a 10μ aluminum foil using a polyurethane resin adhesive, and then a polyolefin obtained by using polyethylene instead of polypropylene was applied to the aluminum foil surface according to Example 1. The resin films were stacked together using a laminator (190°C) to form a laminated film. This laminated film was spirally wound over the entire surface of a polyethylene cylindrical object having a wall thickness of 1 mm as the inner surface of the polyolefin resin film while being heated by ultrasonic waves (cylindrical object). Next, thickness 1
A laminator (190°C) is used to laminate aluminum foil onto a polyethylene sheet of 1.5 in. It was thermocompression bonded to a cylindrical body using the heat seal impulse method. The peel strength of the joint between the cylindrical body and the lid of the obtained container was 1.5 Kg/cm.
Other tests are shown in Table 1. Comparative Example 1 A container with a bottom made of polypropylene with a wall thickness of 1 mm is made by injection molding. The upper lid is also made of a 1mm thick polypropylene sheet, and the joints are fused using a thermal seal. The peel strength of the joint between the cylindrical body and the lid of the obtained container was 1.5 kg/. Other tests are shown in Table 1. Comparative Example 2 In manufacturing the cylindrical body of Example 3, a polyurethane resin adhesive was used instead of the polyolefin resin film as the laminated film, and the laminated film was wound spirally around the entire surface of the polyethylene cylindrical body. Next, aluminum foil is pasted onto a 1 mm thick polyethylene sheet via polyurethane resin, a polyurethane resin adhesive is roll coated onto the aluminum foil, and a lid with polyethylene coated paper pasted on top is made into a cylindrical body. Thermocompression bonding was performed using the heat seal impulse method. The test method shown in Table 1 will be described below. Γ Pressure Resistance The containers obtained in Examples and Comparative Examples were placed in an autoclave and examined for deformation, cracking, and poor adhesion under pressure. ΓOxygen gas barrier properties Under 1 atm, a cylindrical body treated with (), (), or () is passed through a cylindrical body in contact with oxygen gas at an interface of 1 m ² for 24 hours. Measure the amount of oxygen gas passing through. Γ Retortability When manufacturing containers, coffee beverages are added as contents and retort sterilized at 125°C for 6 minutes. After retort sterilization, abnormalities in the container joints and decrease in peel strength are measured. The results before retort sterilization are also shown. Consumption of Sodium Permanganate Extrusion test is conducted in accordance with the test of Ministry of Health and Welfare No. 434. Note that it passes if it is 10 ppm or less.

[Table] As shown in Table 1, the containers obtained in Examples 1 and 2 are useful as pressure-resistant containers, and in Example 3, they cannot be used as containers for retort sterilization, but they have good oxygen gas barrier properties and hygienic properties. Excellent in
Can be used for general food containers, etc.

[Brief explanation of the drawing]

1 to 8 are cross-sectional views showing embodiments of the present invention. Codes in the figure: 1, 2 -- cylindrical body, 3, 4, 6,
7--Lid, 5--Part that becomes the outlet of the lid, 8
--Easy open type outlet.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a container, which comprises performing the following (), (), or () on the outer surface of a thick-walled cylindrical object made of polyolefin, and then performing (). () Lamination of polyolefin resin and aluminum foil, in which α/β-ethylenically unsaturated carboxylic acid and metal compound are heat-blended with polyolefin, and at least α/β-ethylenically unsaturated carboxylic acid is graft-polymerized to polyolefin. While heat-sealing the film to a cylindrical object with the polyolefin resin as the inner surface, the film is wound spirally over the entire surface, and then an adhesive and one type selected from polyolefin film, polyester film, polyamide film, and polyolefin processed paper are applied on top of the film. Wrap the laminated film in a spiral over the entire surface with adhesive as the inner surface. () A laminated film of the polyolefin resin and aluminum foil is wound spirally over the entire surface while heat-sealing the polyolefin resin on the inner surface of the cylindrical object, and an adhesive is coated thereon, and then a polyolefin film is formed. One type selected from polyester film, polyamide film, and polyolefin processed paper is laminated. () The polyolefin resin, aluminum foil, adhesive, and polyolefin film,
A laminated film made of one type of film selected from polyester film, polyamide film, and polyolefin-processed paper is spirally wound over the entire surface while being heat-sealed with polyolefin resin as the inner surface. () polyolefin sheet or film, the polyolefin resin, aluminum foil, adhesive, and polyolefin film,
Top and bottom lids made of one selected from polyester film, polyamide film, and polyolefin-processed paper are respectively adhered to the cylindrical object on which (), (), or () has been applied.