JPH0929916A - Material for container and container composed thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of cracks in a foamed sheet part and wrinkles in the body part of a container at a time of the curl processing of the lip part of the container by specifying the whole thickness of a laminate containing a thermoplastic foamed polyester sheet specified in density, thickness and a basis wt. and paper specified in thickness. SOLUTION: A material of the cup body part of a container is composed of a laminate containing a sheet of a thermoplastic foamed polyester layer 21 with density of 0.1-0.5g/cm<3> , a thickness of 0.2mm or more and a basis wt. of 100g/m<2> or more and paper 20 with a thickness of 0.15mm or more and the whole thickness thereof is set to 1.1mm or less. When the whole thickness exceeds 1.1mm, the seaming of a bottom part and lip curl processing become impossible because the material is too thick. In order to impart sufficient heat insulating properties to the container, it is necessary to set the density of the thermoplastic foamed polyester sheet to 0.5g/cm<3> or less and the thickness thereof to 0.2mm or more. When the thickness of the thermoplastic foamed polyester sheet is below 0.2mm and/or that of paper is below 0.15mm, there is the buckling possibility of the body part at a time of the curl processing of a lip part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container material suitable for a container (hereinafter also referred to as a cup) for maintaining the quality of contents for a long period of time, and a container made of the material. The present invention relates to a container material suitable for a container that accommodates an article or the like that is sensitive to moisture and oxygen, and a container made of the material.

[0002]

2. Description of the Related Art For containers such as cup noodles, a plate-shaped material is punched to form fan-shaped side blanks, both ends of the side blanks are overlapped with each other, and the portions are heat-sealed to form a truncated cone-shaped body. The bottom portion is formed by forming a portion, arranging the bottom plate at the small-diameter side end portion, folding the small-diameter side end portion inward so as to enclose the periphery of the bottom plate, and heat-sealing the portion to form the bottom portion. Further, in such a container, in order to improve the mouthfeel at the opening, the opening end is curled outward to form a curled lip.

As such a container, a container formed of an expanded polystyrene sheet, which is a material having excellent heat insulating properties, is known for pouring hot water into the container for use. In the case of this container, since the expanded polystyrene sheet is brittle, there is a possibility that cracking and damage may occur during molding of the curled lip portion, and therefore sufficient attention must be paid to the molding operation.

Therefore, in order to solve the above problems, a container having a polypropylene foam sheet having a foaming ratio of 2 to 8 and a thickness of 0.3 to 1.6 mm as a trunk portion has been proposed (actually 5-4.
3967). However, since the curling of the lip portion is performed while pressing the entire body in the vertical direction, when such a curling process is performed on a container having a body with poor rigidity as described above, the body buckles. As a result, wrinkles are formed on the body, resulting in a significant decrease in commercial value.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and does not cause cracks in the foamed sheet portion at the time of curling the container lip portion, and the container body portion is not cracked. An object of the present invention is to provide an excellent container and a material for the container which are free from wrinkling due to buckling.

Another object of the present invention is to provide a container excellent in heat insulating property, moisture proof property and gas (oxygen) barrier property, and a material for the container.

[0007]

The material for containers of the present invention comprises:
Laminate comprising a thermoplastic expanded polyester sheet having a density of 0.1 to 0.5 g / cm ³ , a thickness of 0.2 mm or more, and a basis weight of 100 g / m ² or more, and a paper having a thickness of 0.15 mm or more. The total thickness is 1.1 mm or less.
Further, the container of the present invention has a body formed of the above-mentioned material. Further, the container of the present invention has a thickness of 0.02 mm or more as a bottom member of a cup of thermoplastic polyester,
It is composed of a member including a gas barrier resin layer selected from the group consisting of nylon and ethylene vinyl acetate alcohol copolymer. Furthermore, the mouth of the container of the present invention is flattened.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In a normal paper cup molding machine, if the thickness of the material forming the body exceeds 1.1 mm, the seam processing and lip curl processing at the bottom cannot be performed because it is too thick. Especially when seaming the bottom part, pinholes tend to be formed between the body part and the bottom part in the vicinity of the heat-sealed parts at both ends of the body side blank, which causes the container's waterproofness and moisture resistance to deteriorate. There is a risk. Further, in order to give the container sufficient rigidity to be used, the thickness of the paper needs to be 0.15 mm or more, and the foamed polyester sheet laminated on the paper has a density of 0.1 g / cm ³ or more ( (Preferably 0.2 g / cm ³ or more) and a thickness of 0.2 mm or more. Further, in order to impart sufficient heat insulation to the container, the density of the thermoplastic expanded polyester sheet must be 0.5 g / cm ³ or less (preferably 0.4 g / cm ³ or less), and The thickness of the sheet must be 0.2 mm or more. Especially, the thickness of the thermoplastic expanded polyester sheet is 0.2 m.
When the thickness is less than m and / or the thickness of the paper is less than 0.15 mm, the body portion may buckle when the lip portion of the container having such a laminated sheet is curled. There is also.

On the other hand, in order to keep the contents of the container in a dry state for a long period of time and suppress oxygen permeation as much as possible, the basis weight of the thermoplastic expanded polyester sheet is set to 100 g / m ² or more. There is a need. From the viewpoints of such moisture resistance and gas barrier property, the lid used for such a container is also desired to have moisture resistance and gas barrier property at the same level or higher. Such lids contain a single gas barrier resin such as thermoplastic polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), nylon (nylon 6, nylon 6,6, nylon MXD6, etc.), or ethylene vinyl acetate alcohol copolymer. From the viewpoint of moisture resistance and safety of gas barrier property, it is preferable that the container opening portion is formed of a layered sheet or a multilayered sheet and sealed in the container opening by heat sealing. In such a case, it is desirable to curl the lip portion and then press and crush the curl portion from the vertical direction of the container at the final stage of the curl processing to form a flat portion on the lip portion. When such a flat portion is present, heat sealing of the lid becomes extremely easy, and the degree of safety of moisture resistance and gas barrier property is enhanced. Such processing is sufficiently possible with the container made of the container material of the present invention. In addition, when the thermoplastic foamed polyester sheet is adopted as a material for a container, there is an effect that the foamed sheet portion constituting the lip portion is unlikely to be cracked when the lip portion is flattened.

The material for the container of the present invention and the paper constituting the container have a density of from 0.6 to 0.6 manufactured by an ordinary papermaking method.
The thing of about 1.0 g / cm ³ is preferably used. Such paper is the one used in commercial paper cups.

As an adhesive for adhering the above-mentioned paper and the foamed polyester sheet, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified polyethylene, adhesive modified polyester, propylene and a small amount of maleic anhydride can be used. Examples thereof include a polymer, a copolymer of ethylene and a small amount of maleic anhydride, a copolymer of propylene and a small amount of methacrylic acid, and a copolymer of ethylene and a small amount of methacrylic acid. The thickness of the adhesive is usually 10
It is about 50 μm.

Further, it is preferable to form a resin layer (laminate layer) having a waterproof property and a heat seal property on the inner surface of the body. Examples of the resin layer include polyethylene, polypropylene, nylon, ethylene-ethyl acrylate copolymer (EEA), ethylene-vinyl acetate copolymer (EVA), and the above adhesives. The thickness is preferably 15 to 50 μm. Since the thermoplastic expanded polyester and the polyolefin resin do not have adhesiveness, the above-mentioned adhesive is used when adhering them.

The outer surface of the body is preferably laminated with polyethylene, polystyrene, nylon, or polyvinyl chloride in order to facilitate printing and protect the body. The thickness is preferably 15 to 50 μm.

Further, as the bottom plate of the container, since the bottom is not gripped by hand, heat insulation is unnecessary, but moisture resistance and gas barrier properties are required as in the case of the body.
In the bottom plate of the container of the present invention, paper for ensuring rigidity (density of 0.6 to 1.0 g / cm produced by an ordinary papermaking method) is used.
³ about things) a thermoplastic polyester, nylon, it is preferable to form a resin layer having both waterproof and heat-sealing properties through the gas barrier layer such as ethylene vinyl acetate alcohol copolymer (laminate layer). As the resin layer, polyethylene, polypropylene, nylon, ethylene-ethyl acrylate copolymer (EEA),
Examples include ethylene-vinyl acetate copolymer (EVA), the above adhesives, and the like. The resin that is the same as or similar to the inner surface of the body is most preferable from the viewpoint of heat sealability.

[0015]

The function of the container material according to the present invention is to improve workability, moisture resistance, and
Has excellent gas barrier properties, heat insulation properties and rigidity. Therefore, according to this material, it is possible to manufacture using a conventional cup forming machine, and by using a container using this material, the quality of the contents in the container can be maintained for a long time. Further, even when hot water is poured into the container, the container can be easily grasped by hand.

[0016]

【Example】

-Examples 1-2, Comparative Examples 1-5-Fig. 1 shows a cup 1 molded from the container material of the present invention.
0 is shown. As shown in FIG. 2, the material of the cup body 11 is T when the paper 20 fed from the roll 1 and the thermoplastic foamed polyester (polyethylene terephthalate) sheet 21 fed from the roll 2 are superposed by the roll 3. Maleic anhydride graft modified polyethylene resin (melt adhesive resin) 22 extruded from the die 4
(Thickness 20 μm) and then maleic anhydride-modified resin (heat sealing resin) 2 on roll 5
3 (thickness 20 μm) was extruded from a die 6 and laminated on the surface to form a maleic anhydride graft modified resin layer on the surface. The material constructed in this way is
As shown in FIG. 3, a paper sheet 20, a maleic anhydride graft-modified polyethylene resin 22, a thermoplastic expanded polyester sheet 21, and a maleic anhydride graft-modified polyethylene resin 23 are laminated in this order. Then, the laminated sheet is punched out in a fan shape in accordance with the cup shape to obtain a side blank (a material for a body portion) as shown in FIG. This is applied to a cup molding machine so that the maleic anhydride graft-modified polyethylene resin layer 23 is on the inner surface, and the body portion 11 of the cup is molded, the ends are overlapped and heat-sealed together, and the lower edge is placed inside. After folding, the bottom plate 12 was embraced and heat-sealed (so that the resin layer 26 described later is inside the container) to be integrated. Next, a curl was once formed on the upper edge, and then the curl was pressed from above and below under heating to form a flat lip (flat processed mouth portion) 13. The bottom plate 12 is
As shown in FIG. 5, a thermoplastic polyester (polyethylene terephthalate) resin layer 25 is formed on a 150 μm paper 24.
Was extruded and laminated to a thickness of 50 μm, and a maleic anhydride graft-modified polyethylene resin layer 26 was extruded and laminated.

The heat insulation test was conducted at a temperature of 23 ° C. and a humidity of 50%.
In a room, add hot water (95 ℃) to a 500cc cup for 30
After pouring 0 cc and after 5 minutes with the lid open, the surface temperature of the side wall of the cup was measured. After 5 minutes, the temperature inside the container reached about 70 ° C, at which time the surface temperature of the surface of the container held by the container was 6
Those having a temperature difference of 0 ° C. or less, that is, having a temperature difference of 10 ° C. or more were passed (evaluation ◯), and those having a temperature difference of less than 10 ° C. were rejected (evaluation x).

Regarding the rigidity, when curling the container mouth portion with a cup molding machine, the case where buckling causes wrinkles in the body portion is regarded as a failure (x), and one which does not cause buckling is passed ( ○).

The leakage of the internal liquid occurs at the bottom heat seal portion. This is because, as shown in FIG. 6, a void A is formed in a portion where the overlapping portion of the body portion 11 and the bottom plate 12 are superposed, and if the void A is too large, the liquid in the cup leaks out. The leak test is performed using hot water containing instant coffee (9
(0 ° C.) was poured into the cup and left for a while to check for leaks. When there was no liquid leakage, the evaluation was ◯, and when there was liquid leakage, the evaluation was x.

Moisture-proof property is a value that does not deteriorate the content (powder) by a moisture permeability test method according to JIS Z0222, and a value of 20 g / m ² · 24 hrs or less is passed (evaluation ○), 20 g / m ² Those having a size of more than m ² · 24 hrs were regarded as rejected (evaluation ×).

For the gas barrier property, an oxygen permeability measuring instrument (OXTRAN-100) manufactured by MOCON was used to measure the permeability coefficient at room temperature of 23 ° C. and humidity of 65% to obtain 30 cc / m ² · atm.・ 24 hrs or less was passed (evaluation ○). Regarding the above-mentioned moisture proof test and gas barrier property test, it was judged that it is not necessary to carry out these tests for those that were evaluated as x in the liquid leakage test.

[0022]

[Table 1]

Table 1 shows the results of an experiment in which the density, thickness, and basis weight of the thermoplastic expanded polyester sheet were variously changed, and the thickness of the paper was variously changed. Each cup had a size of height: about 10 cm, caliber: about 9.8 cm, bottom diameter: 7.5 cm, and volume: 500 cc. In Examples 1 and 2, the density, thickness, grammage, paper thickness and total thickness of the thermoplastic expanded polyester sheet are all within the scope of the present invention, and all of them are heat insulating, moisture proof, gas (oxygen) of the cup. ) The barrier property was sufficient, liquid leakage was not observed, and the rigidity was sufficient.

On the other hand, in Comparative Example 1, since the thermoplastic expanded polyester sheet has a high density, the heat insulating property cannot be obtained. In Comparative Example 2, the thermoplastic expanded polyester sheet has a small thickness and the slab of the sheet is small. Since the amount was small, the heat insulation, moisture resistance, and gas barrier properties were all inadequate. In Comparative Example 3, the overall thickness was too thick, and heat sealing of the bottom portion was insufficient, causing liquid leakage. Further, in Comparative Example 4, since the paper thickness is thin and the thermoplastic polyester foam sheet has a small basis weight, sufficient moisture resistance and gas barrier properties cannot be obtained, and when the container mouth is curled, Wrinkles have occurred on the body due to buckling. In Comparative Example 5, the overall thickness was too large, and heat sealing of the bottom portion was insufficient, causing liquid leakage.

FIG. 7 shows the structure of another embodiment of the body of the container according to the present invention. (A) shows that the outer surface of the structure of the above embodiment is laminated with polyethylene, polystin, nylon, vinyl chloride to facilitate printing,
A laminate layer 26 is formed to protect the body. In (b), the laminate layer 23 formed on the inner surface of the above embodiment is removed. In (c), the laminate layer 23 formed on the inner surface of the structure of the above embodiment is removed, and the laminate layer 26 is formed on the outer surface. In (d), the paper 20 and the thermoplastic foamed polyester layer 21 of the above-mentioned embodiment are replaced. In (e), the paper 20 and the thermoplastic expanded polyester layer 21 of the above embodiment are replaced with each other, and the laminate layer 26 is formed on the outer surface.

[0026]

EFFECTS OF THE INVENTION In a container using the container material according to the present invention as a body, wrinkles due to buckling do not occur in the body of the container even when the container mouth is curled, On the other hand, even if the flat processing is performed, the foamed sheet portion is not damaged. Further, since the container according to the present invention is excellent in moisture resistance, heat insulation and gas (oxygen) barrier property, the contents of the container, for example, powdery or solid soup dried product, etc. are protected from moisture and oxygen for a long time. The quality is maintained for a long time. Further, even if hot water is poured into the container when eating or drinking, the container has a heat insulating effect, so that the container can be easily grasped by hand.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a cup molded using the material for a container of the present invention.

FIG. 2 is a view conceptually showing a molding step of the material for a container of the present invention.

3 is a view showing a structure of a material formed through the process of FIG. 2, and is a sectional view taken along line III-III in FIG.

FIG. 4 is a plan view showing a side blank obtained by punching out the material of FIG.

5 is a diagram showing a configuration of a bottom plate of the cup, which is a cross-sectional view taken along line VV in FIG.

6 is a view showing the structure of the cup bottom portion and is a cross-sectional view taken along line VI-VI in FIG.

FIG. 7 is a constitutional view showing another embodiment of the container material of the present invention.

[Explanation of symbols]

 1,2,3 rolls 4 T dies 5 rolls 6 T dies 10 cups 11 body 12 bottom 13 top curl 20 paper 21 thermoplastic foam polyester layer 22 adhesive layer 23 laminate layer 24 paper 25 gas barrier layer 26 laminate layer

Claims (4)

[Claims] 1. A thermoplastic expanded polyester sheet having a density of 0.1 to 0.5 g / cm ³ , a thickness of 0.2 mm or more, and a basis weight of 100 g / m ² or more, and a thickness of 0.15 mm.
A container material having a total thickness of 1.1 mm or less, which is a laminate including the above paper. 2. A container having a body formed from the container material according to claim 1. 3. The bottom plate material includes a gas barrier resin layer selected from the group consisting of thermoplastic polyester, nylon and ethylene vinyl acetate alcohol copolymer having a thickness of 0.02 mm or more. The container according to 2. 4. The container according to claim 2, wherein the mouth portion is flattened.