JP2022190385A - Container and bag body - Google Patents

Abstract

To provide a container and a bag body which facilitate packaging of contents.SOLUTION: There is provided a container in which a film composed of a thermoplastic resin is bonded to an upper surface of a container body composed of a thermoplastic resin. The container body has a flange part, and a part of the flange part constitutes a fastener of the film peeled from the container body.SELECTED DRAWING: Figure 1

Description

The present invention relates to containers and bags.

BACKGROUND ART Conventionally, plastic containers have been used as containers for foods such as vegetables sold and boxed lunches. From the point of view of environmental protection, more and more plastic containers are recycled, but recycling requires cleaning of the plastic containers.

In order to save labor for cleaning, a container has been proposed in which a peelable film is attached to the inside of the container body (see, for example, Patent Documents 1 and 2). By peeling off the film from the container body after use, dirt on the container can be removed together with the film.

JP-A-2000-225662 JP 2017-200744 A

When the peeled film is discarded, the dirt adhering to the film may spill out from the film. Therefore, when you try to tie the ends of the film, you may touch the dirty film surface and get your hands dirty.

SUMMARY OF THE INVENTION An object of the present invention is to provide a container and a bag that facilitate packaging of contents.

The inventors of the present invention have completed the present invention as follows as a result of intensive studies in order to solve the above problems.

(1) A container in which a film made of a thermoplastic resin is adhered to the upper surface of a container body made of a thermoplastic resin,
The container body has a flange,
A container, wherein a part of the flange portion constitutes a fastener for the film peeled off from the container body.

(2) The container according to (1) above, wherein the fastener is provided with a hole inside and a notch extending from the outer periphery to the hole.

(3) The container according to (1) or (2) above, wherein the flange portion is provided with one or a plurality of cuts along the outer periphery of the fastener.

(4) The container according to any one of (1) to (3) above, wherein the flange surface includes an uneven portion having an uneven structure and a smooth portion having no uneven structure.

(5) The container according to (4) above, wherein the fastener is located on the smooth portion.

(6) The container according to any one of (1) to (5), further comprising an adhesive layer between the film and the container body.

(7) A bag body in which the film peeled off from the container according to any one of (1) to (6) above is closed in a bag shape by the fastener cut from the flange portion of the container.

ADVANTAGE OF THE INVENTION According to this invention, the container and bag body which packaging of a content is easy can be provided. Since the bag body has a small bottom surface area, the contents can be stored compactly.

It is a perspective view showing a container of one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1; 1 is a perspective view of a container from which the film is peeled; FIG. It is a figure which shows the bag formed with the peeled film.

Hereinafter, the container and bag of the present invention will be described in detail, but the configuration described below is an example (representative example) of the present invention, and the present invention is not limited thereto.
In the following description, the description of "(meth)acrylic" indicates both acrylic and methacrylic.

[container]
FIG. 1 shows a container 1 of this embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG.
The container 1 comprises a container body 2 and a film 3. The container body 2 is a thermoformed thermoplastic resin sheet 2', and the film 3 is a thermoplastic resin film. The film 3 is adhered to the upper surface of the container body 2 and constitutes the surface layer on the upper surface side of the container 1 . From the viewpoint of adjusting the adhesive strength between the container body 2 and the film 3 , the container 1 preferably has an adhesive layer 4 between the container body 2 and the film 3 .

In addition, the container 1 may be provided with a cover member that covers the upper side of the container body 2 . In order to fix the cover member to the container body 2, a cover member or the like that fits with the container body 2 or is thermally adhered can be used. Alternatively, the lid member and the container body 2 may be integrally formed so that a part of the lid member is connected to the container body 2 .

The film 3 can be manually peeled from the container body 2 as shown in FIG. After the container 1 is used, the container body 2 from which the film 3 has been removed can be recycled as it is. Even if the top surface of the container 1 is soiled by the contents, the soiling can be removed together with the film 3, saving labor for cleaning and facilitating recycling.

The peeled film 3 can also be used as a packaging film. By squeezing the ends of the film 3 together, a bag 5 can be formed as shown in FIG. can accommodate.

Further, the container body 2 has a flange portion 22 , and a portion of the flange portion 22 constitutes the fastener 6 for the film 3 . The opening of the bag 5 can be closed by cutting the fastener 6 from the container body 2 and fastening the squeezed neck portion of the bag 5 with the fastener 6 . Since the fastener 6 can be obtained from the container 1, there is no need to prepare another fastener such as a string. Since there is no need to tie the ends of the film 3, the hands can be easily and firmly fastened without getting the hands dirty.

Details of each configuration will be described below.
(container body)
The container body 2 includes a housing portion 21 and a flange portion 22 . These are usually integrally molded from a thermoplastic resin.

<Accommodation part>
The housing portion 21 may be in the shape of a deep bowl or in the shape of a dish. Examples of the shape of the bottom surface of the housing portion 21 include a polygonal shape such as a square, a circular shape, an elliptical shape, and the like.

The size of the containing portion 21 can be appropriately selected according to the size of the contents. Usually, the long side of the bottom surface of the housing portion 21 (referring to the longest overall length in the case of a square, the diameter in the case of a circle, and the major axis in the case of an ellipse) is 50 mm or more and 500 mm or less, and the depth is 30 mm or more and 300 mm or less. is.

From the viewpoint of moldability and strength of the container 1, it is preferable that the bottom surface of the container 21 is square, circular, or elliptical. In addition, it is preferable that the storage portion 21 is bowl-shaped, since the film 3 peeled from the container body 2 can be easily formed into the bag body 5 . From the same point of view, it is preferable that the long side or diameter of the bottom surface is longer than the depth of the accommodating portion 21 . Therefore, the ratio of the long side or diameter to the depth is more preferably 1 or more, and usually 20 or less.

The thickness of the housing portion 21 can be selected as appropriate, but from the viewpoint of increasing the compressive strength of the container 1, the thickness is preferably 200 μm or more, more preferably 250 μm or more, and even more preferably 300 μm or more. From the viewpoint of cost reduction, the thickness is preferably 800 μm or less, more preferably 500 μm or less.

Also, the corners of the bottom surface or the wall surface are usually rounded in an arc shape, and the radius thereof is preferably about 5 to 20 mm. Due to the roundness, the film 3 has a curved surface after being peeled off, making it easier to use as the bag body 5. - 特許庁

<Flange>
The flange portion 22 protrudes outward from the end portion of the housing portion 21 . Deformation of the container 1 can be suppressed by the flange portion 22 . Moreover, the flange portion 22 makes it easier to grip the container 1 by hand.

The width from the inner circumference to the outer circumference of the flange portion 22 can be selected according to the contents of the container 1, but is usually 5 mm or more.
The thickness of the flange portion 22 can be the same as the thickness of the housing portion 21 .

<< clasp >>
As mentioned above, part of the flange portion 22 constitutes the fastener 6 for the film 3 . The fastener 6 has a C-ring shape, and is provided with a hole 61 inside and a notch 62 leading from the outer periphery to the hole 61 . By inserting the neck of the bag body 5 into the hole 61 through the notch 62, the neck can be pinched by the fastener 6 and fastened.

In this embodiment, the flange portion 22 is provided with a plurality of cuts 22c along the outer circumference of the fastener 6. As shown in FIG. Thereby, a perforation line is provided on the outer circumference of the fastener 6 . By twisting the portion of the flange portion 22 that constitutes the fastener 6, the fastener 6 can be easily cut off from the flange portion 22 by hand.

The number of cuts 22c can be changed depending on the length of the cuts 22c, and may be one. From the viewpoint of ease of cutting, the number of connection points between the fastener 6 and the flange portion 22 where the notches 22c are not provided is preferably 5 or less, more preferably 3 or less, and even more preferably 2. .

In the present embodiment, one corner of the flange portion 22 is projected and the fastener 6 is formed on the projecting portion. The fastener 6 may be configured within a range of widths.

<< Concavo-convex part and smooth part >>
From the viewpoint of adjusting the adhesive strength of the film 3, the surface of the flange portion 22 can be provided with an uneven portion 22a having an uneven structure. Although the uneven portion 22a may be provided on the entire surface of the flange portion 22, it may be provided on a part of the flange portion 22 instead of the entire surface. In this case, the flange portion 22 includes an uneven portion 22a and a smooth portion 22b that does not have an uneven structure. The concave-convex portion 22a can be formed by providing a concave-convex structure in a mold used for thermoforming the container 1. As shown in FIG. Since the concave-convex portion 22a is formed in the process of thermoforming the container 1, the concave-convex portion 22a can be easily formed without increasing the manufacturing process.

The fastener 6 is preferably provided on the smooth portion 22 b of the flange portion 22 . By providing the smooth portion 22b, which has a lower mechanical strength than the uneven portion 22a, the fastener 6 can be easily cut off.

The edges of the container 1, such as the flanges 22, are susceptible to impact during use of the container 1. Moreover, since the interface between the film 3 and the container body 2 is exposed, the film 3 tends to peel off at the flange portion 22 . However, the concave-convex structure of the concave-convex portion 22 a functions to fit the film 3 to the container body 2 . Therefore, peeling of the film 3 can be suppressed by the uneven portion 22a. On the other hand, the film 3 is easily peeled off at the smooth portion 22b that does not have an uneven structure that prevents peeling. Therefore, the smooth portion 22b can be used as a trigger for peeling of the film 3, which facilitates peeling after use.

The adhesive strength of the film 3 of the entire flange portion 22 including the uneven portion 22a and the smooth portion 22b is preferably 0.5 N/15 mm or more, more preferably 2 N/15 mm or more, from the viewpoint of suppressing peeling of the film 3 when the container 1 is used. preferable. From the viewpoint of facilitating peeling of the film 3 after use of the container 1, the adhesive strength is preferably 20 N/15 mm or less, more preferably 15 N/15 mm or less, and even more preferably 10 N/15 mm or less.
The adhesive strength can be adjusted by the material of the adhesive layer 4, the interval or depth of the concave portions (or convex portions) of the concave-convex structure, and the like.

On the other hand, the adhesive strength of the film 3 in the smooth portion 22b is preferably 0.01 N/15 mm or more from the viewpoint of suppressing unnecessary peeling during use, and 0.5 N/15 mm from the viewpoint of giving a trigger for peeling of the film 3. Less than is preferred.
The adhesive strength is a value measured by a 180° peel test based on JISZ 0238:1998 using a strip-shaped sample from the flange portion 22 .

When the flange portion 22 has no uneven portion 22a and the entire surface is a smooth portion 22b, from the viewpoint of suppressing peeling of the film 3 during use of the container 1, it is preferably 2 N/15 mm or more, more preferably 4 N/15 mm or more, and 6 N/ 15 mm or more is more preferable. From the viewpoint of facilitating peeling of the film 3 after use of the container 1, the adhesive strength is preferably 20 N/15 mm or less, more preferably 15 N/15 mm or less, and even more preferably 10 N/15 mm or less.

The pattern of the uneven structure includes, for example, a pattern in which unevenness is distributed in stripes, nets, dots, zigzags, waves, or the like. An uneven structure having a pattern such as wood grain or texture may be selected according to the application of the container 1 .

From the viewpoint of suppressing unnecessary peeling during use, the arithmetic mean roughness Ra of the surface of the uneven portion 22a is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more. From the viewpoint of facilitating manual peeling after use, the arithmetic mean roughness Ra is preferably 5.0 mm or less, more preferably 3.0 mm or less, and even more preferably 1.0 mm or less. On the other hand, the surface arithmetic mean roughness Ra of the smooth portion 22b is usually about 0.01 to 0.1 mm.

From the viewpoint of suppressing peeling of the film 3, the distance d between the concave portions (or the convex portions and the convex portions) in the uneven portion 22a is preferably 1.5 mm or less, more preferably 1.2 mm or less. From the viewpoint of reducing catching or tearing when the film 3 is peeled off, the distance d is preferably 0.2 mm or more, more preferably 0.3 mm or more.

From the viewpoint of suppressing peeling of the film 3, the ratio of the distance between the concave portions to the depth of the concave portions (or the ratio of the distance between the convex portions to the height of the convex portions) is preferably 0.5 to 5 times.

Further, the wall surface of the concave portion or convex portion may be inclined with respect to the surface of the smooth portion 22b of the flange portion 22. FIG. The inclination angle θ is preferably 45° or more, more preferably 50° or more, but may be 110° or less, preferably 90° or less.

In the flange portion 22, the uneven portion 22a can be provided in a region excluding a portion that triggers peeling. The smooth portion 22b that triggers peeling may be provided at any position on the flange portion 22 .

When the accommodating portion 21 has a square shape, it is preferable that the smooth portion 22b be provided at one or more of the four corners of the flange portion 22 . The four corners are easy to trigger peeling by hand, and the film 3 after peeling is easy to pick up by hand, thus facilitating peeling. In the present embodiment, smooth portions 22b are provided at all four corners, and peeling can be performed from any of the corners.

The uneven portion 22a can be arranged on the outer peripheral side of the flange portion 22, and the smooth portion 22b can be arranged on the inner peripheral side. When the container 1 is provided with a lid member, the lid member is arranged so as to be in contact with the smooth portion 22b. In this case, the uneven portion 22a prevents the film 3 from peeling off during normal use, and the smooth portion 22b serves as a trigger for peeling after the lid member is removed.

<Thermoplastic resin>
Examples of thermoplastic resins that can be used for the container body 2 include olefin-based resins, ester-based resins, and styrene-based resins.

Olefin-based resins that can be used for the container body 2 include, for example, propylene-based resins and ethylene-based resins such as high-density polyethylene having a density of 0.942 g/cm ³ or more and 0.965 g/cm ³ or less. From the viewpoint of suppressing drawdown, it is also preferable to blend 5 to 25% by mass of long-chain branched polypropylene with the polyolefin.

From the viewpoint of controlling thickness unevenness during molding of the container body forming sheet 2', the melt flow rate of the olefin resin is preferably 0.2 g/10 min or more, more preferably 0.5 g/10 min or more. On the other hand, from the viewpoint of suppressing drawdown, the melt flow rate is preferably 5.0 g/10 min or less, more preferably 3.0 g/10 min or less. The melt flow rate is a value measured under conditions of a heating temperature of 230° C. and a load of 2.16 kgf according to JIS K7210.

Examples of ester-based resins that can be used for the container body 2 include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), and the like. Copolymers in which a part of the monomers of these resins are replaced with comonomers such as isophthalic acid, naphthalene-2,6-dicarboxylic acid, adipic acid, trimethylene glycol, or 1,4-cyclohexanedimethanol are also used. can also These comonomer-derived components may be contained in the ester resin in an amount of 1 to 25% by mass.

The limiting viscosity of the ester-based resin is preferably 0.5 dl/g or more, more preferably 0.6 dl/g or more, from the viewpoint of stable molding of the container body forming sheet 2'. On the other hand, from the viewpoint of suppressing drawdown, the intrinsic viscosity is preferably 1.3 dl/g or less, more preferably 1.1 dl/g or less. The intrinsic viscosity is a value measured at a temperature of 30° C. after dissolving 1.0 g of a sample in 100 ml of a mixed solvent in which phenol and tetrachloroethane are mixed at a weight ratio of 50:50.

From the viewpoint of moldability, the glass transition point (Tg) of the ester resin is preferably 40 to 110°C, more preferably 50 to 100°C. The glass transition point (Tg) was determined by sampling 5 mg from the container body-forming sheet 2', melting in nitrogen at 285°C for 5 minutes, and then quenching. It is a value measured by differential scanning calorimetry.

Examples of the styrene-based resin that can be used for the container body 2 include general-purpose polystyrene (GPPS), rubber-modified polystyrene, and mixtures thereof. General purpose polystyrene resins usually refer to styrene homopolymers. Rubber-modified polystyrene resin is also called high impact polystyrene (HIPS).

The container body 2 can contain a filler. From the viewpoint of reducing the resin material in the container body 2, the content of the filler in the container body 2 is preferably 5% by mass or more, and more preferably 10% by mass or less. On the other hand, the content of the filler is preferably 60% by mass or less, more preferably 50% by mass or less, from the viewpoint of increasing the compressive strength during molding.
In addition, as a filler, the filler similar to the film 3 mentioned later can be used.

The container body 2 may be a foam. Examples of foaming methods include known methods such as chemical foaming, physical foaming, and supercritical foaming. From the viewpoint of weight reduction of the container body 2, the expansion ratio is preferably 1.1 times or more, more preferably 1.5 times or more. On the other hand, from the viewpoint of suppressing deformation, the expansion ratio is preferably 3 times or less, more preferably 2 times or less.

The container body 2 may have a single-layer structure or a multi-layer structure. A multilayer structure is preferable because the adhesive strength of the film 3 can be adjusted by the type of thermoplastic resin in the outermost layer.

(the film)
Since the film 3 is a thermoplastic resin film having excellent mechanical strength, it is easily adhered to the container body 2 and is excellent in handleability as a packaging film after peeling.

<Thermoplastic resin>
Examples of thermoplastic resins that can be used for the film 3 include olefin-based resins, ester-based resins, styrene-based resins, amide-based resins such as nylon-6, nylon-6,6, nylon-6,10, and nylon-6,12. Resins, vinyl chloride resins, polycarbonate resins, and the like can be mentioned. These can be used alone or in combination of two or more. From the viewpoint of mechanical strength, the film 3 preferably contains an olefin resin or an ester resin as a main component, and more preferably contains an olefin resin as a main component. A main component means that the content in a film exceeds 50 mass %.

Olefin-based resins that can be used for the film 3 include propylene-based resins, ethylene-based resins, and the like. Among them, propylene-based resins are preferable from the viewpoint of moldability and mechanical strength.

Examples of propylene-based resins include propylene homopolymers such as isotactic homopolypropylene and syndiotactic homopolypropylene obtained by homopolymerizing propylene, propylene-based ethylene, 1-butene, 1-hexene, 1-heptene, Examples include propylene copolymers obtained by copolymerizing α-olefins such as 1-octene and 4-methyl-1-pentene. The propylene copolymer may be a binary system or a ternary or higher multicomponent system, and may be a random copolymer or a block copolymer.

Ester-based resins that can be used for the film 3 include polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate.

<Filler>
The film 3 can contain fillers. Examples of fillers include inorganic fillers and organic fillers. The inclusion of a filler facilitates the formation of a porous resin film. Also, the whiteness or opacity of the film 3 can be increased. The filler contained in the film 3 may be one of the above inorganic fillers or organic fillers, or may be a combination of two or more.

Of these, inorganic fillers are preferred from the viewpoint of cost, ease of selection of particle size, and the like. Examples of inorganic fillers include inorganic particles such as heavy calcium carbonate, light calcium carbonate, titanium oxide such as rutile-type titanium dioxide, calcined clay, silica, diatomaceous earth, clay or talc. Among them, heavy calcium carbonate, clay or diatomaceous earth is preferable because it has good pore moldability and is inexpensive. For the purpose of improving dispersibility, etc., the surface of the inorganic filler may be surface-treated with a surface-treating agent such as fatty acid.

From the viewpoint of increasing the whiteness or opacity of the film 3, the content of the filler in the film 3 is preferably 10% by mass or more, more preferably 15% by mass or more. Moreover, from the viewpoint of improving the uniformity of molding of the film 3, the content of the filler in the film 3 is preferably 70% by mass or less, more preferably 50% by mass or less.

The average particle size of the filler is preferably 0.01 µm or more, more preferably 0.1 µm or more, from the viewpoint of ease of forming pores. From the viewpoint of imparting mechanical strength such as tear resistance, the average particle size of the filler is preferably 15 μm or less, more preferably 5 μm or less.

The average particle diameter of the inorganic filler is the volume average particle diameter corresponding to 50% of the cumulative volume (cumulative 50% particle diameter) measured by a particle measuring device such as a laser diffraction particle size distribution measuring device (Microtrac, manufactured by Nikkiso Co., Ltd.). is.

<Other additives>
Optionally, the film 3 may contain antifog agents, lubricants, antiblocking agents, antistatic agents, antioxidants, heat stabilizers, light stabilizers, weather stabilizers, or UV absorbers commonly used in the polymer field. It can contain the additives used. The content of these additives in film 3 is usually 0.01 to 5% by mass independently for each type of additive.

<Thickness and structure>
The thickness of the film 3 is preferably 20 μm or more, more preferably 40 μm or more, from the viewpoint of suppressing the generation of wrinkles or tearing during peeling. On the other hand, from the viewpoint of weight reduction, the thickness of the film 3 is preferably 200 μm or less, more preferably 150 μm or less.

The film 3 may have a single layer structure or a multilayer structure. In the case of a multilayer structure, each layer can impart various functions such as white opacity, adhesion to ink used in the printed layer, adhesion between the film 3 and the adhesive layer 4, and heat insulation.

The film 3 may be a non-stretched film or a stretched film. From the viewpoint of mechanical strength, the film 3 is preferably a stretched film, more preferably a biaxially stretched film.

The surface of the film 3 may be activated by an activation treatment from the viewpoint of enhancing adhesion with adjacent layers. Examples of the activation treatment include corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment, ozone treatment, and the like. Among them, corona discharge treatment or flame treatment is preferable, and corona treatment is more preferable.

(adhesion layer)
The adhesive layer 4 quasi-adheres the film 3 to the container body 2 . Pseudo-adhesion means that the adhesive strength is such that it does not separate from the container body 2 during normal use, but the adhesive strength is such that the film 3 can be peeled off by hand.

Due to pseudo-adhesion, the film 3 is peeled off at the interface between the film 3 and the adhesive layer 4 or at the interface between the adhesive layer 4 and the container body 2 . Alternatively, the film 3 is peeled off due to cohesive failure of the adhesive layer 4 .

The adhesive layer 4 can be formed by using a thermoplastic resin as its material and extruding the resin composition. The adhesive layer 4 can also be formed by using an adhesive as the material of the adhesive layer 4 and applying the adhesive.

<Thermoplastic resin>
Thermoplastic resins that can be used for the adhesive layer 4 include those similar to those used for the film 3 .

From the viewpoint of sufficient adhesion between the film 3 and the container body 2, as the thermoplastic resin for the adhesive layer 4, low- or medium-density polyethylene with a density of 0.900 to 0.935 g/cm ³ and a density of 0.935 g/cm 3 are used. 880-0.940 g/cm ₃ linear low-density polyethylene, metallocene-based polyethylene produced using a metallocene catalyst, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid alkyl ester The melting point of the copolymer, the ethylene-methacrylic acid alkyl ester copolymer having 1 to 8 carbon atoms in the alkyl group, and the metal salt of ethylene-methacrylic acid copolymer such as Zn, Al, Li, K, Na, etc. Ethylene-based resins of 60 to 130° C. are preferred. Among them, low- or medium-density polyethylene having a crystallinity of 10 to 60% and a number average molecular weight of 10,000 to 40,000, or linear low-density polyethylene, as measured by an X-ray method, is more preferable.

From the viewpoint of adhering the film 3 releasably, it is preferable to use a thermoplastic resin incompatible with the surface layer of the container body 2 for the adhesive layer 4 . Specifically, when the container body 2 is made of an olefin resin, it is preferable to use an ester resin, a styrene resin, or the like for the adhesive layer 4 . Further, when the container body 2 is made of an ester-based resin or a styrene-based resin, it is preferable to use an olefin-based resin for the adhesive layer 4 .

From the viewpoint of adjusting the adhesive strength, a thermoplastic resin compatible with the surface layer of the container body 2 may be used in combination with the thermoplastic resin incompatible with the surface layer. For example, if sufficient adhesive strength cannot be obtained by using an olefin resin for the surface layer of the container body 2 and a styrene resin for the adhesive layer 4, the olefin resin can be used in combination with the styrene resin to increase the adhesive layer 4 of the container. The bonding strength with the main body 2 can be increased.
From the viewpoint of pseudo-adhesion, the amount of the compatible thermoplastic resin used in combination with the incompatible thermoplastic resin is preferably 30% by mass or less, more preferably 20% by mass or less, based on the total amount.

The thermoplastic resin used for the adhesive layer 4 may have a lower melting point than the thermoplastic resin for the film 3 . When the film 3, the adhesive layer 4 and the container body forming sheet 2' are laminated by applying heat and pressure, the film 3 can be laminated without being melted. Further, when the container 1 after use is heated, the adhesive layer 4 having a low melting point melts and the film 3 is easily peeled off.

From the viewpoint of facilitating control of the adhesive strength, the adhesive layer 4 may contain a tackifier or a plasticizer. Examples of tackifiers include hydrogenated petroleum resins, aromatic hydrocarbon resins, and aliphatic hydrocarbon resins. Hydrogenated petroleum resins include, for example, partially hydrogenated petroleum resins. Examples of aromatic hydrocarbon resins include terpene-based resins, rosin-based resins, and styrene-based resins. The tackifier or plasticizer may be used alone or in combination of two or more. From the viewpoint of suppressing peeling of the adhesive layer 4 during normal use, the thermoplastic It is preferable that the compatibility with the resin is high.

In the case of using a thermoplastic resin, the thickness of the adhesive layer 4 is preferably 0.5 μm or more, more preferably 0.7 μm or more, and even more preferably 1 μm or more, from the viewpoint of improving adhesion. From the viewpoint of suppressing cohesive failure inside the adhesive layer 4, the thickness is preferably 10 μm or less, more preferably 6 μm or less.

<Adhesive>
Examples of adhesives that can be used for the adhesive layer 4 include acrylic adhesives, silicone adhesives, urethane adhesives, and rubber adhesives. These can be used singly or in combination of two or more. Among them, acrylic pressure-sensitive adhesives or silicone-based pressure-sensitive adhesives are preferable because they are less likely to deteriorate or generate odor due to heat during thermoforming.

In the case of using an adhesive layer, the thickness of the adhesive layer 4 is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, from the viewpoint of enhancing adhesiveness. From the viewpoint of suppressing cohesive failure inside the adhesive layer 4, the thickness of the adhesive layer 4 is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less.

<Other additives>
Adhesive layer 4 can contain the same additives as film 3, if desired.

(Print layer)
The container 1 may have a printed layer by printing on the container body 2 or the film 3 . From the viewpoint of facilitating recycling of the container body 2, it is preferable that the film 3 is printed and the container body 2 is not printed.

Any surface of the container body 2 can be printed, but from the viewpoint of avoiding contact with the contents, especially food, the printed layer is preferably provided below the surface layer.
When the film 3 is printed, the surface of the film 3 opposite to the adhesive layer 4 can be printed from the viewpoint of stabilizing the peel strength of the film 3 . From the viewpoint of avoiding contact with the contents, especially food, it is preferable to form a printed layer on the surface of the film 3 on the side of the adhesive layer 4 .

Examples of the printed information include product names, product displays such as logos, manufacturer names, sales company names, usage methods, barcodes, and the like. Examples of printing methods include gravure printing, offset printing, flexographic printing, seal printing, and screen printing.

[Container manufacturing method]
(Manufacturing method by integral molding)
The method of manufacturing the container 1 is not particularly limited, but for example, after laminating the adhesive layer 4 and the film 3, which are thermoplastic resin films, in this order on the sheet 2' for forming the container body, the laminated body is integrally thermoformed. can be manufactured. After thermoforming, a stamping process forms a flange portion 22 from which the fastener 6 can be cut.

<Film or sheet molding>
Examples of the method for forming a single-layer film or sheet include cast molding, calendar molding, rolling molding, and inflation in which a molten resin is extruded into a sheet using a single-layer or multilayer T-die, I-die, or the like connected to a screw-type extruder. Molding and the like can be used. A film or sheet may be formed by casting or calendering a mixture of a resin and an organic solvent or oil, followed by removal of the solvent or oil.

Methods for laminating films and sheets include a coextrusion method, an extrusion lamination method, a coating method, a heat lamination method, and the like, and these methods can also be combined.
In the coextrusion method, resin compositions for each layer melted and kneaded in separate extruders are laminated and extruded in a feed block or multi-manifold, and film formation and lamination are performed in parallel. Extrusion lamination processes extrude a resin composition onto a preformed film to form and laminate another film. In the coating method, a solution, emulsion or dispersion of resin is applied onto the film and dried to form and laminate another film. In the thermal lamination method, the film of the adhesive layer 4 is sandwiched between the film and the sheet and heated to bond them together.

<Stretching>
Each film and sheet may be stretched individually prior to lamination or may be stretched together after lamination. Alternatively, the unstretched film and the stretched film may be laminated and then stretched again.

Stretching methods that can be used include, for example, a longitudinal stretching method using a peripheral speed difference between roll groups, a transverse stretching method using a tenter oven, a sequential biaxial stretching method combining these, a rolling method, and a combination of a tenter oven and a pantograph. Examples include a simultaneous biaxial stretching method, a simultaneous biaxial stretching method using a combination of a tenter oven and a linear motor, and the like. A simultaneous biaxial stretching (inflation molding) method can also be used, in which a circular die connected to a screw extruder is used to extrude a molten resin into a tubular shape, and then air is blown into the tubular shape.

From the viewpoint of suppressing twisting or sinking of the container body 2 after thermoforming, it is preferable to relieve the stress by heating the laminate before thermoforming.

<Thermoforming>
The thermoforming method includes known techniques using a general vacuum forming machine, air pressure forming machine or vacuum pressure forming machine. For example, in a vacuum molding machine, after heating the laminate of the sheet 2' for forming the container body 2, the adhesive layer 4 and the film 3, it is placed in a mold provided with holes. The mold is formed so that the flange portion constituting the fastener 6 protrudes. By sucking from the holes, the laminate is molded in close contact with the mold. In the air pressure molding machine, an air pressure box is provided to pressurize the inside, or the laminate is sandwiched and both vacuum and air pressure are used to press the laminate against the mold. As a result, the mold shape is transferred to the softened laminate. After that, it is cooled by blowing air for several seconds. In the vacuum and pressure molding machine, one side of the laminate is heated with a hot plate and compressed.

As the thermoforming conditions, normal thermoforming conditions can be used. Heating methods include radiant heat from a heater, steam heating, and the like. The heating may be performed from one side of the laminate, or from both sides of the container body forming sheet 2'. Among them, the method of heating both sides of the sheet 2' for forming a container body is preferable because a complicated shape can be stably formed. The sheet temperature is preferably 10 to 30° C. lower than the melting point of the material of the container body forming sheet 2'. For example, polypropylene is heated to about 160°C, and polyethylene terephthalate (PET) is heated to about 250°C.

After the molded container 1 is removed from the mold, if necessary, it is punched out with a punching blade to remove unnecessary portions. The removed unnecessary parts can be pulverized and reused.

<Punching>
The overhanging portion of the flange portion 22 of the thermoform is punched to form the holes 61 and notches 62 of the fastener 6 . Also, the outer periphery of the fastener 6 of the flange portion 22 is punched to provide a notch 22c for a perforation line.

(Manufacturing method by joining)
The container 1 can also be manufactured by thermoforming the container body 2 alone, applying an adhesive to the surface of the film 3 to form the adhesive layer 4, and then bonding the container body 2 and the film 3 together. be.

<Coating of adhesive>
After forming the film 3, an adhesive layer 4 is formed by coating the film 3 with an adhesive. The adhesive can be applied using a coating device such as a roll coater, blade coater, bar coater, air knife coater, size press coater, gravure coater, die coater, lip coater, and spray coater.

<Bonding of films>
A film 3 coated with an adhesive is heated and arranged so as to cover the opening of the container body 2 . After that, air pressure is applied to bring the film 3 into close contact with the container body 2 . As a result, the film 3 can be brought into close contact with the upper surface of the container body 2 and joined. Alternatively, the container body 2 may be provided with a vacuum hole and the film 3 may be adhered to the container body 2 by suction from the container body 2 side.

<Punching>
Also in the manufacturing method by joining, the flange portion 22 can be stamped out in the same manner as in the case of integral molding.

[Container use]
The application of the container 1 is not particularly limited. In particular, the container 1 in which the bag 5 can be formed from the peeled film 3 can be suitably used for food. When storing or discarding the food in the container 1, the food can be protected by the bag body 5, and the food can be discarded without soiling the hands.

[Bag body]
The film 3 peeled from the container 1 can be used as a packaging film for containing the contents of the container 1 . The film 3 can be used as a bag body 5 by putting the ends of the film 3 together and closing the bag with fasteners 6 cut from the container 1 . For example, leftover food in the container 1 can be stored in the bag 5, and unused parts on the container 1 can be stored in the bag 5, which is highly convenient. The fastener 6 can also be obtained from the container 1 and the bag 5 can be easily formed. The bottom surface of the bag body 5 has a smaller area than the bottom surface of the container 1, so that it can be accommodated compactly.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Descriptions of "parts", "%", etc. in the examples are based on mass unless otherwise specified.

[Laminated film (a1)]
Propylene homopolymer (manufactured by Japan Polypropylene Corporation, product name: Novatec PP MA4, MFR (230°C, 2.16 kg load): 5 g/10 minutes, melting point: 167°C) 84% by mass, heavy calcium carbonate fine powder (Bihoku Manufactured by Funka Kogyo Co., Ltd., product name: Softon #1800, volume average particle size: 1.8 μm) 15% by mass, and rutile-type titanium dioxide fine powder (manufactured by Ishihara Sangyo Co., Ltd., product name: Typaque CR-60, volume average particles diameter: 0.2 μm) was mixed with a mixer. Then, the mixture was melt-kneaded at 230° C. using an extruder to prepare a resin composition for a film.

A resin composition for a film was melt-kneaded with an extruder set at 240°C. On the other hand, high impact polystyrene (manufactured by PS Japan Co., Ltd., product name: H9152, MFR (200 ° C., 5 kg load): 5.5 g / 10 minutes) 100% by mass as a resin for the adhesive layer was set at another 240 ° C. The extruder was fed. This was melt-kneaded in an extruder to prepare a resin composition for an adhesive layer.

Each melt-kneaded resin composition was supplied to one co-extrusion T-die, laminated into two layers in the T-die, and extruded into a film form from the T-die at 240°C. As a result, a two-layer film was obtained in which a film made of polypropylene and filler and an adhesive layer made of high-impact polystyrene were laminated. This two-layer film was cooled by a cooling device to obtain a non-stretched film having a two-layer structure. The unstretched film thus obtained was heated to 150° C. and stretched 5 times in the machine direction using the difference in peripheral speed between a plurality of roll groups. Then, after cooling to a temperature of 60° C., the film was heated again to a temperature of 150° C. and stretched 8 times in the transverse direction using a tenter. After annealing at a temperature of 160° C., the film was cooled to a temperature of 60° C. to obtain a white opaque laminated film (a1) having a two-layer structure. The total thickness of the laminated film (a1) was 80 µm (5 µm/75 µm).

[Laminated film (a2)]
High-impact polystyrene (HIPS) used as the adhesive layer resin in the laminated film (a1) and propylene homopolymer (manufactured by Japan Polypropylene Corporation, product name: Novatec PP MA4) were mixed at a ratio of 95% by mass: 5% by mass. A laminated film (a2) having a total thickness of 80 μm (5 μm/75 μm) was obtained in the same manner as the laminated film (a1), except that an adhesive layer was formed.

[Laminated film (a3)]
High-impact polystyrene (HIPS) used as the adhesive layer resin in the laminated film (a1) and propylene homopolymer (manufactured by Japan Polypropylene Corporation, product name: Novatec PP MA4) at a ratio of 50% by mass: 50% by mass A laminated film (a3) having a total thickness of 80 μm (5 μm/75 μm) was obtained in the same manner as the laminated film (a1), except that an adhesive layer was formed.

[Container body forming sheet (b1)]
Propylene homopolymer (manufactured by Japan Polypropylene Corporation, product name: Novatec PP EA9, MFR (230°C, 2.16 kg load): 0.5 g/10 minutes, melting point: 167°C) 70% by mass, heavy calcium carbonate fine powder (manufactured by Bihoku Funka Kogyo Co., Ltd., product name: Softon #1800, volume average particle size: 1.8 μm) 28% by mass, and rutile-type titanium dioxide fine powder (manufactured by Ishihara Sangyo Co., Ltd., product name: Typaque CR-60, volume Average particle size: 0.2 μm) 2% by mass was mixed with a mixer. Then, they were melt-kneaded at 230° C. using an extruder to prepare a resin composition for a base layer. On the other hand, 100% by mass of a propylene homopolymer (product name: Novatec PP EA9, manufactured by Japan Polypropylene Corporation) was melt-kneaded at 230° C. using another extruder to prepare a resin composition for the skin layer.

The melt-kneaded resin composition for the base layer and the resin composition for the skin layer were supplied to one co-extrusion T-die, laminated in the T-die into three layers of skin layer/base layer/skin layer, and extruded at 240°C. It was extruded into a sheet from a T-die. This three-layer sheet was led between a semi-mirror chill roll and a matte rubber roll and cooled while being compressed (linear pressure: about 15 N/cm). After the ear portions were cut off, the sheet was wound up by a winder to obtain a container body forming sheet (b1). The container body forming sheet (b1) was a white polyolefin resin sheet with a three-layer structure, and had a total thickness of 250 μm (10 μm/230 μm/10 μm).

[material]
Table 1 shows a list of raw materials used in the above production.

[Example 1]
A chromium-plated drum dryer was heated to 95° C. with steam, and the laminated film (a1) and the container body forming sheet (b1) were overlapped and passed in the order of container body forming sheet/laminated film from the drum dryer side. Heating was carried out with an infrared heater from the laminated film side, and the sheet surface temperature measured with a radiation thermometer was controlled to be about 140°C. After that, it was nipped with a water-cooled chill roll at a linear pressure of about 20 N/cm, air-cooled to room temperature, and the obtained laminate was wound up.

The laminate was then unwound, heated and vacuum formed using a thermoforming mold. For the thermoforming, a small vacuum forming machine with a forming area of 500 mm×500 mm was used with a top heater heating method.

[Thermoforming mold]
The resulting laminate was heated and vacuum-formed using a thermoforming mold. For the vacuum forming, a small vacuum forming machine with a forming area of 500 mm×500 mm was used with a top heater heating method.
(thermoforming mold)
As the thermoforming mold, a vacuum forming mold having a rectangular bottom with a size of 140 mm×58 mm and a depth of 35 mm was used. The bottom surface has a substantially rectangular shape with four arcuate corners with a radius of 5 mm, and the taper angle of the inner wall surface with respect to the bottom surface is 30 degrees. The four corners of the portion forming the flange portion of the mold were formed in an arc shape with a radius of 15 mm. An elliptical projecting portion was provided at one of the four corners of the portion forming the flange portion of the mold. Except for the projecting portion and the four corners, the surface of the mold portion forming the flange portion was provided with an uneven structure having a rhombus-shaped pattern with internal angles of 30 degrees and 60 degrees. The distance between the concave portions of this concave-convex structure was 1 mm, and the depth of the concave portions was 0.5 mm.

The molded body was taken out from the vacuum molding machine and trimmed along the outer periphery of the flange portion. Also, by punching, a hole was provided in the center of the elliptical projecting portion and a notch leading from the outer periphery of the flange portion to the hole was provided. In addition, the perimeter of the projecting portion was partially punched out to provide a notch for the perforation line. Thus, a container of Example 1 provided with a C-ring-shaped fastener as shown in FIG. 1 was manufactured.

[Example 2]
A container of Example 2 was produced in the same manner as in Example 1, except that the laminated film (a1) used in Example 1 was changed to the laminated film (a2).

[Reference example 1]
In the same manner as in Example 1, except that the laminated film (a1) was replaced with the laminated film (a3), and the concave-convex structure of the mold was used as it was during thermoforming without filling the concave-convex structure of the mold to form the concave-convex portion on the entire flange portion. A container of Reference Example 1 was manufactured.

[Reference example 2]
The uneven structure of the surface forming the flange portion of the thermoforming mold used in Example 1 was all filled with silicone resin and thermoformed, and the uneven portion was not formed in the flange portion. A container of Reference Example 2 was produced in the same manner.

[evaluation]
The containers of Examples and Reference Examples were evaluated as follows.

(Action of fastener)
Two apples were placed in the containers of Examples and Reference Examples, one of which was taken out on the assumption that the apple was eaten, and the other was left in the container. The fastener was then snapped off from the flange of the container. Furthermore, as shown in FIG. 3, the film was peeled off from the four corners of the flange portion, and as shown in FIG. 4, the ends of the film were put together to form a bag for wrapping an apple. The neck of the bag was fastened with a fastener to close the opening, and finally the bag was peeled off from the bottom of the container.

The film was peeled off from each of the containers of Examples 1 and 2 and Reference Example 2, and the peeled film could be used to easily form a bag containing the contents of the container. In addition, it was confirmed that the fastener could be easily cut off from the container, and that the fastener could be used to close the bag and accommodate it compactly.

(adhesion strength)
A test piece of 60 mm×15 mm was cut from the flange portion of the molded container to prepare a test piece. When the uneven portion 22a was provided on a part of the flange portion, the test piece was cut so as to include a portion with the uneven portion 22a and a portion without the uneven portion 22a. Three test pieces were taken from one container. Using this test piece, a 180-degree peel test was conducted in accordance with JISZ 0238:1998 (testing method for heat-sealable flexible packaging bags and semi-rigid containers).

A 10 mm portion on one end of the test piece was peeled off to separate the film and the sheet, and an auxiliary piece of 80 mm×15 mm was attached to the film with cellophane tape. One end of the separated sheet side of the test piece was fixed to the lower chuck of a universal testing machine (manufactured by Shimadzu Corporation, model: AG-100kNXplus), and the auxiliary piece was fixed to the upper chuck. Subsequently, peeling was performed at a tensile speed of 300 mm/min and an angle of 180 degrees, and the maximum load was recorded. The average value of the measured values for three test pieces was evaluated as the adhesive strength (N/15 mm) of the film. The adhesive strength of the test piece partially provided with the uneven portion 22a is the adhesive strength of the entire flange portion 2 including the uneven portion 22a and the smooth portion 22b.

(Hand peel test)
From the container of each example and reference example, the degree of difficulty when starting to peel off the surface film was sensory evaluated as follows.
Excellent: Already peeled off and can be peeled off without using fingernails. Acceptable: Can be peeled off with fingernails. Poor: Cannot be peeled off with fingernails.

(Actual use test)
Two apples were placed in the container of each example and reference example, and the top surface of each sample was covered with a wrap film. After arrival, the package was unpacked, and it was visually confirmed that the film had risen from the container body at the flange portion of the container.
Excellent: There is no float on the uneven part, and there is float on the smooth part. Cannot be seen Impossible: Float progresses to the inner surface of the housing part inside the flange part

Table 2 shows the evaluation results.

As shown in Table 2, according to Examples 1 and 2, by providing an uneven portion on the flange portion of the container, it is difficult to peel off in actual use, but it can be easily peeled off by hand. On the other hand, Reference Example 1, in which the uneven portion was provided on the entire flange portion, had a high adhesive strength, and it was difficult to peel off the film by hand. In Reference Example 2, which does not have uneven portions, the film was easy to peel off by hand, but it was peeled off during the actual use test.

DESCRIPTION OF SYMBOLS 1... Container, 2... Container body, 22... Flange part, 22a... Uneven part, 22b... Smooth part, 3... Film, 4... Adhesive layer, 5...・Bag body 6... Fastener 61... Hole 62... Notch

Claims (7)

A container in which a film made of a thermoplastic resin is adhered to the upper surface of a container body made of a thermoplastic resin,
The container body has a flange,
A container, wherein a part of the flange portion constitutes a fastener for the film peeled off from the container body. 2. The container according to claim 1, wherein the fastener is provided with a hole inside and a notch extending from the outer periphery to the hole. 3. A container according to claim 1 or 2, wherein the flange portion is provided with one or more cuts along the circumference of the fastener. The container according to any one of claims 1 to 3, wherein the flange portion surface comprises an uneven portion having an uneven structure and a smooth portion having no uneven structure. 5. A container according to claim 4, wherein the fastener is located on the smooth portion. The container according to any one of claims 1 to 5, further comprising an adhesive layer between the film and the container body. A bag body in which the film peeled off from the container according to any one of claims 1 to 6 is closed in a bag shape by the fastener cut from the flange portion of the container.

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