JP4052791B2 - container - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inner surface of a papermaking container main body having a flange portion at the periphery of an opening end portion and a container formed by coating the flange portion with a resin, and particularly relates to a container suitable for a container for food and drink.
[0002]
[Prior art and problems to be solved by the invention]
As a prior art regarding the inner surface of a papermaking container main body having a flange portion at the periphery of the opening end portion and a container formed by covering the flange portion with a resin film, for example, a technique described in JP-A-4-261837 is disclosed. Are known. This technique is a food container in which a thermoplastic resin film is laminated and fused on the inner surface and flange portion of a container that has been made into a predetermined shape in advance.
[0003]
By the way, in the above-mentioned conventional technology, since the peripheral end portion of the flange portion is exposed to the outside, the strength may be lowered due to water immersion or the like, and the touch and appearance are also poor. In addition, since the strength of the flange portion is low, when the lid is bonded to the upper surface of the flange portion, the flange portion may be bent when the lid is peeled off, making it difficult to peel off. There was a risk that it would peel off itself.
[0004]
On the other hand, as a conventional technique in which a paperboard laminated with a resin film is bent into a cup-shaped container, a container disclosed in Japanese Patent No. 3075142 is known. This container is formed by bonding a paperboard laminated with a resin film into a predetermined shape and joining it to form a bottomed cylindrical cup body, and a protective cover that covers the side wall of the cup body. The side wall of the opening end periphery of the cup body is curled outwardly and further flattened in the vertical direction to form a flange portion, and the inner surface of the flange portion is brought into a non-contact state. In addition, the self-restoration of the flange portion is restricted by the upper end portion of the protective cover, the overhang length of the flange portion is increased, and the contact area with the lid is increased.
[0005]
However, since the inner surface of the flange portion formed in this way is maintained in a non-contact state, the shape is unstable, and the dimensional accuracy of the flange portion is not always satisfactory. Also, it is easily deformed when an external force, particularly when a force is applied to the flange portion from the horizontal direction. For example, when the flange portion is covered and pressurized and welded, the flange portion is deformed downward. In order to escape, sufficient sealing performance may not be obtained. Furthermore, when a flange portion is formed in such a technique on a papermaking container having a short fiber length compared to paperboard and having no fiber orientation, the flange portion is broken when the flange portion is curled. There was a fear. In addition, the curled portion easily wrinkles, which is not preferable in terms of appearance.
[0006]
Accordingly, an object of the present invention is to provide a container that can give a desired strength to the flange portion, can prevent water from entering from the end of the flange portion, and has a good appearance.
[0007]
[Means for Solving the Problems]
According to the present invention, in a container in which a papermaking container main body having a flange portion at the periphery of the opening end portion is provided with an inner surface and a resin layer covering the flange portion, a hanging portion that hangs downward from the periphery portion is provided on the flange portion. Have The hanging portion has a folded portion that is folded inward from a lower end portion thereof, and a distal end portion of the folded portion is disposed at a position higher than a folded base portion. Ahead The end is concealed by the hanging part, The object is achieved by providing a container in which an outer surface portion and a lower end portion of the hanging portion are covered with the resin layer.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below based on preferred embodiments with reference to the drawings.
FIG. 1 shows a container for instant cup noodles according to an embodiment of the container of the present invention. In the same figure, the code | symbol 1 has shown the container.
[0009]
As shown in FIG. 1, the container 1 is provided with a resin film layer (resin layer) 3 that covers the inner surface and the flange portion 20 on a papermaking container body 2 having a flange portion 20 on the periphery of the opening end. The flange portion 20 has a hanging portion 21 that hangs downward from the peripheral portion thereof, and an outer surface portion and a lower end portion of the hanging portion 21 are covered with the resin film layer 3. In this specification, drooping means drooping vertically and substantially vertically.
[0010]
The container 1 also has a folded portion 22 that is folded inward from the lower end portion of the hanging portion 21. The folded portion 22 extends to the inside of the hanging portion 21 and below the flat portion 20 a, and is integrally joined to the inner surface of the hanging portion 21 and the back surface of the flat portion of the flange portion 20. The front end portion 22a of the folded portion 22 is disposed at a position higher than the folded base portion, and the front end portion 22a is concealed by the drooping portion 21 to enhance the appearance and water resistance.
[0011]
The width W of the flat portion 20a of the flange portion 20 is not hot when the flange portion 20 is strong, the sealing performance when the lid is closed, the bending workability, the mouth feel, and the mouth of the flange portion 20. Therefore, it is preferably 2 to 5 mm, and more preferably 2.5 to 4 mm. Further, the thickness T of the flat portion 20a of the flange portion 20 is preferably 0.8 to 3.0 mm, and more preferably 1.2 to 2.0 mm, from the viewpoint of securing the strength of the flange portion.
[0012]
The height H1 of the drooping portion 21 is preferably 2 to 5 mm, and more preferably 2.5 to 4 mm in terms of the strength of the flange portion, mouth feel, and protection of the tip portion 22a.
[0013]
The papermaking container main body 2 includes an inner pulp layer 2A and an outer pulp layer 2B that are made mainly from pulp, and a foaming agent layer 4 between the inner pulp layer 2A and the outer pulp layer 2B. The container 1 has a total layer thickness (hereinafter referred to as thickness when referring to the thickness) according to the foaming ratio of the foaming agent of the foaming agent layer 4, and is a value measured by the measurement method of the examples described later. And a portion having a different total layer density in the body portion 22, and the total layer thickness and the total layer density are different in the vertical direction of the body portion 23.
[0014]
The total thickness and density of the body portion 23 of the container 1 are different from each other at the steps 23a and 23b, and the thickness of the whole layer increases and the total layer density decreases as the body portion 23 moves downward. . The level difference 23a indicates a hot water injection standard, and the level difference 23b is a level difference (stacking level difference) when the empty containers are stacked. In this way, the foaming agent is densified in the portion close to the opening portion to increase the strength, and the foaming agent is reduced in density from the central portion to the bottom portion of the body portion 23 serving as the gripping portion to provide high heat insulation. It can be granted. The steps 23a and 23b accompanying the change in the total thickness of the body portion 23 are formed in the inner pulp layer 2A. Thus, the surface of the outer pulp layer 2B, which is the outer surface of the container 1, can be formed flat by forming the steps 23a and 23b in the inner pulp layer 2A according to the change in the total thickness of the body portion 23. Good printability can be obtained.
[0015]
The density of the inner pulp layer 2A and the outer pulp layer 2B is as follows: surface smoothness, surface strength, compressive strength, waterproofness, shape retention, prevention of paper dust generation during stacking, filling the contents, or stacking containers 0.2-1.5 g / cm in terms of cushioning properties ^Three Preferably, 0.4 to 1.0 g / cm ^Three It is more preferable that
In the container 1, the density of the outer pulp layer 2B is higher than the density of the inner pulp layer 2A in that the outer pulp layer 2B mainly has shape retaining performance such as compressive strength, stack strength, and grip strength. Is preferred.
[0016]
From the viewpoint of making the container 1 a thin-walled container, in particular, the total layer thickness (for example, the thickness T2 of the trunk portion in FIG. 1 (a)) in a portion requiring heat insulation is 0.8 to 5 mm. Preferably, it is 1.3-5 mm, and it is most preferable that it is 1.6-4 mm. In addition, the thickness of the inner pulp layer is preferably 0.2 to 1 mm from the viewpoints of stability at the time of papermaking, shape retention, thin and light weight and compression strength, papermaking or shortening of drying time, More preferably, it is 0.4-1 mm, and most preferably 0.5-1 mm. Moreover, in the same point as the inner pulp layer, the thickness of the outer pulp layer is preferably 0.2 to 1 mm, more preferably 0.4 to 1 mm, and 0.5 to 1 mm. Most preferred.
[0017]
In the container 1, the surface smoothness of at least the inner surface of the inner pulp layer 2 </ b> A is the same as that of the examples described later in terms of adhesion to the resin film described later, prevention of pinhole generation in the resin film, and the like. In the centerline average roughness Ra and the maximum height Rmax measured by the method, Ra is 1 to 20 μm (value measured according to JIS B 0601. The same applies hereinafter), and Rmax is 100 μm or less (according to JIS B 0601). It is preferable that Ra is 2 to 10 μm, and Rmax is 80 μm or less.
[0018]
In the container 1, the surface smoothness of at least the outer surface of the container 1 in the outer pulp layer 2 </ b> B is centerline average roughness measured by the method of Examples described later in terms of improving printability. In Ra and the maximum height Rmax, Ra is preferably 1 to 8 [mu] m and Rmax is preferably 60 [mu] m or less, Ra is preferably 2 to 6 [mu] m, and Rmax is preferably 50 [mu] m or less. On the other hand, the portion of the outer pulp layer 2B that comes into contact with the foaming agent layer 4 to be described later increases the contact area between the outer pulp layer 2B and the foaming layer 4 to increase the joint strength between them, It is preferable to make the paper with a rougher surface and finish the surface relatively rough.
[0019]
The inner pulp layer 2A and the outer pulp layer 2B are made mainly from pulp, and may be composed only of pulp fibers. In addition, the pulp fibers include inorganic substances such as talc and kaolinite, glass fibers and carbon fibers. It is also possible to contain other components such as inorganic fibers such as polyolefin, powder or fiber of thermoplastic synthetic resin such as polyolefin, non-wood or vegetable fiber, polysaccharides. The blending amount of these other components is preferably 1 to 70% by weight, particularly 5 to 50% by weight, based on the total amount of pulp fibers and other components. Further, the inner pulp layer 2A and the outer pulp layer 2B may contain a fiber dispersant, a molding aid, a coloring pigment, a coloring aid, and the like that are appropriately added at the time of paper making.
[0020]
The foaming agent layer 4 is a layer mainly composed of a foaming agent, and may be composed only of the foaming agent. In addition, the foaming agent may be an inorganic material such as pulp fiber, talc or kaolinite, or an inorganic material such as glass fiber or carbon fiber. It may contain other components such as fiber, powder of thermoplastic synthetic resin such as polyolefin, fiber, non-wood or vegetable fiber, polysaccharide. The blending amounts of these other components are set as appropriate so that the density of the foaming agent layer is not increased and the heat insulating property is not lowered and the container weight is not increased. As the foaming agent used in the foaming agent layer 4, a foaming agent such as a microcapsule-type foaming agent, a foamable resin, an inorganic foaming agent such as sodium hydrogen carbonate is preferably used, and among these, the expansion ratio can be increased. A microcapsule type foaming agent is preferable from the viewpoint of excellent handleability, and in particular, a content such as butane or pentane and a skin such as vinylidene chloride or acrylonitrile are preferably used.
[0021]
In the container 1, the foaming agent layer 4 is formed between the inner and outer pulp layers 2A and 2B, and has a predetermined heat insulating performance. Specifically, it is preferable that the temperature difference value measured by the method of Examples described later is 20 to 40 ° C., the surface temperature is 50 to 65 ° C., the temperature difference value is 25 to 35 ° C., and the surface temperature. Is more preferably 55-60 ° C.
[0022]
In the container 1, the flange portion 20 is formed by joining the inner pulp layer 2 </ b> A and the outer pulp layer 2 </ b> B to the periphery of the opening without the foaming agent layer 4. Thus, by joining the inner pulp layer 2A and the outer pulp layer 2B without the foaming agent layer 4, the flange portion 20 can be made thin and strong, and the subsequent processing can be easily performed. Moreover, since there is no foaming agent in the flange part 20, there is no worry of mistaking the foaming agent.
[0023]
The resin film layer 3 is a layer for imparting water resistance (leakage resistance), gas barrier properties and the like to the container. Accordingly, the resin film used for the resin film layer 3 is not particularly limited in its material, thickness, etc., as long as it can provide its function. For example, polyolefin resin such as polyethylene or polypropylene, polyethylene terephthalate, etc. Polyester resins, polyamide resins such as nylon, polyvinyl resins such as polyvinyl chloride, and thermoplastic resins such as styrene resins such as polystyrene. Among these, polyolefins are used in terms of film production cost, moldability, etc. A resin is particularly preferably used. Further, the resin film layer 3 may have either a single layer structure or a multilayer structure.
[0024]
In the container 1, the inner / outer pulp layers 2A and 2B and the foaming agent layer 4 are formed with a mixed layer at the boundary between the inner pulp layer 2A and the foaming agent layer 4, and both are firmly formed by the mixed layer. And integrated at the boundary between the outer pulp layer 2B and the foaming agent layer 4 by fusing the foaming agent. Since the inner pulp layer 2A and the foaming agent layer 4 are firmly integrated, high heat insulation and shape retention can be obtained even when hot water or the like is poured.
[0025]
Next, a method for manufacturing the container 1 will be described with reference to the drawings.
In the manufacturing method of the container 1, first, the inner pulp layer 2A and the outer pulp layer 2B are individually made. As will be described later, each pulp layer can be made using a set of production molds composed of a male mold and a female mold. The male mold has, for example, a paper-making part having a desired shape on the outer surface and a gas-liquid flow passage leading to the outer surface and a predetermined opening and wire diameter covering the paper-making part. The one provided with a resin net is used. The male papermaking part used for papermaking is made of an elastic body such as heat-resistant and corrosion-resistant rubber. By using a mold having a papermaking portion formed of an elastic body in this way, a molded body having a complicated surface shape and a deep drawn portion can be formed. On the other hand, for the female mold, a concave metal mold having an inner surface corresponding to the male papermaking portion is used. In addition, it is preferable to use a female die provided with a heating means because it can be dried in addition to dehydration.
[0026]
For example, as shown in FIGS. 2A and 2C, the inner pulp layer 2A and the outer pulp layer 2B immerse the male molds 10 and 11 in the pools P1 and P2 holding the slurry for each pulp layer. After that, the slurry is sucked through the gas-liquid flow passage (not shown), and pulp fibers are made with the net (not shown), so that the outer surfaces of the nets of the male molds 10 and 11 are wetted. Paper is made in the state.
[0027]
As the slurry used for forming each pulp layer, a slurry composed only of pulp fibers and water is preferably used. In addition to pulp fibers and water, inorganic substances such as talc and kaolinite, inorganic fibers such as glass fibers and carbon fibers, thermoplastic synthetic resin powders or fibers such as polyolefins, non-wood or plant fibers, polysaccharides, etc. It may contain components. The blending amount of these components is preferably 1 to 70% by weight, particularly 5 to 50% by weight, based on the total amount of pulp fibers and the components. In addition, a pulp fiber dispersant, a molding aid, a coloring agent, a coloring aid, and the like can be appropriately added to the slurry. Moreover, a sizing agent, a pigment, a fixing agent and the like can be appropriately added to the slurry. In particular, when the outer pulp layer dried to a predetermined moisture content and the wet inner pulp layer are integrated by adding a sizing material, the outer pulp layer absorbs moisture from the inner pulp layer. It is possible to prevent appearance defects such as stains on the outer surface of the outer pulp layer.
[0028]
From the standpoint that the foaming agent layer 4 can be formed by efficiently foaming the foaming agent, the outer pulp layer 2B is preferably dried in advance and densified before being overlapped with the inner pulp layer 2A. Specifically, after papermaking for a predetermined time, the male mold 11 is pulled up from the slurry and is brought into contact with a metal female mold 12 corresponding to the male mold 11 as shown in FIG. The female mold 12 is preferably one having no exhaust holes on the inner surface so as not to leave behind on the outer surface of the outer pulp layer 2B, but has an exhaust hole when desiring to shorten the drying time. Things can also be used. Then, the outer pulp layer 2B in a wet state is pressed by the paper making part of the male mold 11 to perform dehydration, and the female mold 12 is heated by the heating means (not shown), and the outer pulp layer 2B is dried to increase the height. Densify. When the outer pulp layer 2B is dehydrated and dried, the moisture (water and steam) of the outer pulp layer 2B is sucked through the gas-liquid passage of the male mold 11 and drained to the outside. The pressing force at the time of dehydration / drying of the outer pulp layer 2B is preferably 0.2 to 3 MPa, more preferably 0.3 to 1.5 MPa from the viewpoint of increasing the density by increasing the dewatering efficiency. preferable. Further, the mold temperature (temperature of the female mold 12) at the time of drying the outer pulp layer 2B is preferably 150 to 230 ° C, and preferably 170 to 220 ° C in terms of prevention of scorching due to drying, drying efficiency, and the like. It is more preferable. After the outer pulp layer 2B is dehydrated and dried, the outer pulp layer 2B is transferred from the male mold 11 to the female mold 12. After the delivery is completed, the male mold 11 is retracted.
[0029]
While increasing the density of the outer pulp layer 2B as described above, the outer surface of the inner pulp layer 2A is covered with a foaming agent. For example, as shown in FIG. 2 (d), the foaming agent is coated with a male mold 10 in which the inner pulp layer 2 </ b> A is made in a pool P <b> 3 containing a foaming agent-containing liquid (foaming agent dispersion or solution). It can be performed by dipping and impregnating the outer surface of the inner pulp layer 2A.
[0030]
As the foaming agent, one that expands by heating can be used without particular limitation, but from the viewpoint of suppressing the burning of the pulp fiber of the pulp layer by heat foaming, the foaming temperature is preferably 100 to 190 ° C, A thing of 110-160 degreeC is more preferable. Examples of the foaming agent having such foaming temperature and dispersibility in water or slurry include microcapsule foaming agents, foaming resins, etc. Among these, particularly in terms of foaming ratio, handling properties, etc. A microcapsule type foaming agent is preferably used. As the microcapsule-type foaming agent, for example, a microcapsule-type foaming agent whose content is butane, pentane or the like and whose outer skin is vinylidene chloride, acrylonitrile or the like is preferably used. In addition, for example, a kneaded material in which baking soda, an azo compound, a nitroso compound, a hydrazide compound or the like (hereinafter referred to as baking soda) is kneaded into starch or a resin can be used, or pulp and starch can be added to the baking soda or the like. Foamed beads can also be used.
[0031]
The amount of the foaming agent is preferably 1 to 20% by weight with respect to the total weight of the container from the viewpoint of making the foaming agent layer 4 the predetermined density and thickness, production cost, and the like. More preferably, it is 10% by weight.
[0032]
Next, the inner pulp layer 2A and the outer pulp layer 2B are overlapped so that the foaming agent layer 4 is located between the inner pulp layer 2A and the outer pulp layer 2B. That is, as shown in FIG. 2 (e), the inner pulp layer 2A impregnated with the foaming agent is superposed from above the dehydrated and dried outer pulp layer 2B disposed in the female mold 12. At this time, the inner pulp layer 2 </ b> A is not removed from the male mold 10, and the male mold 10 is directly butted against the female mold 12. Then, the inner pulp layer 2 </ b> A and the outer pulp layer 2 </ b> B are brought into close contact with each other while pressing the wet inner pulp layer 2 </ b> A at the papermaking portion of the male mold 10 to perform dehydration. Thereafter, the compressed air is purged through the gas-liquid flow passage in the male mold 10, and the inner pulp layer 2 </ b> A is transferred from the male mold 10 to the female mold 12. After delivering the inner pulp layer 2A, the male mold 10 is retracted.
[0033]
Next, as shown in FIG. 2 (f), a male male mold 13 having a predetermined clearance C corresponding to a change in the thickness of all layers with the steps 23a and 23b of the container 1 as a boundary is arranged to form a female mold. 11 and press against. Similar to the male mold 10, the male mold 13 includes a gas-liquid flow passage (not shown), and also includes heating means (not shown). Then, the male mold 13 and the female mold 12 are heated by respective heating means, the foaming agent impregnated in the inner pulp layer 2A is foamed to lower the density of the foaming agent layer 4, and the inner pulp layer 2A and the outer pulp The layer 2B is integrated. Further, the flange portions are joined and integrated by a pressing force during drying. In order to increase the adhesive strength, it is preferable to use an adhesive for joining the flange portions, and it is particularly preferable to use an adhesive such as starch as a food container.
[0034]
Regardless of the pressing force at the time of drying, it is preferable that a predetermined clearance is maintained immediately before taking out. During this time, the moisture in the inner pulp layer 2A is drained to the outside as water vapor through the male gas-liquid flow passage. The mold temperature at the time of drying is preferably 150 to 230 ° C. from the viewpoint of maintaining the drying efficiency at a high level while keeping the pulp layers 2A and 2B not to be scorched and being not less than the foaming start temperature. It is more preferable that it is 170-220 degreeC.
[0035]
When the foaming agent foams to a predetermined expansion ratio and the inner pulp layer 2A is dried to a predetermined moisture content, the heating and drying are finished. And the container (semi-finished product) formed by opening the male mold 13 and the female mold 12 is demolded.
[0036]
Next, the flange portion is cut into a predetermined shape. In the cutting step, as shown in FIG. 3 (a), the dried container is inverted and placed on the cutting base 15, and the cutting unit 14 having the cylindrical blade 14a and the pressing ring 14b is flanged. A ring-shaped notch 21a for pressing from the back side of the portion 20 to cut the peripheral edge of the flange portion 20 at a predetermined position and to prevent the pulp fiber from being broken during the subsequent bending process. It is formed at a predetermined position. The depth of the notch 21a is preferably 0.1 to 0.6 mm, and more preferably 0.2 to 0.4 mm. Notches can be provided at two or more locations according to the bending process to be performed subsequently.
[0037]
Next, a primary bending process is performed. In the primary bending process, as shown in FIG. 3B, the container is inserted into the male mold 16, and the cylindrical presser 17A heated to a predetermined temperature is inserted into the ring-shaped concave groove 16a of the male mold 16. The drooping portion 21 that is inserted and droops from the peripheral edge of the flange portion 20 is formed. After the hanging part 21 is formed, the pressing element 17 is retracted. The temperature (surface temperature) of the male mold 16 is preferably 100 to 160 ° C. and more preferably 110 to 130 ° C. in order to maintain the bending property by the iron effect and improve the surface property.
[0038]
Next, the resin film layer 3 is formed. As shown in FIG. 3C, the resin film layer 3 is formed on the outer side (surface) of the inner pulp layer 2A in a state where the container is inverted. The resin film layer 3 can be formed by a conventional method such as vacuum forming. In the case of vacuum forming, a vacuum having substantially the same dimensions as the female mold (see FIG. 2) used in the dewatering / drying process of the outer pulp layer 2B and vacuum suction paths 18a, 18b and a band heater (not shown). Using the mold 18, a semi-finished container is set in the vacuum mold 18, and a resin film is set so as to close the opening of the container. Then, a plug (not shown) provided with a heater is brought into contact with the resin film from above to soften the resin film and butt the mold 18, while utilizing the air permeability of each pulp layer of the container. The container is evacuated through the suction paths 18a, 18b, and the resin film is brought into close contact with the surface of the inner pulp layer 3.
[0039]
Next, a secondary bending process is performed. In the secondary bending process, first, the container is inverted again and inserted into the male mold 16 as shown in FIG. Then, while rotating the male mold 16 around its central axis, blow hot air of a predetermined temperature, while rotating the flange 19a of the rotary presser 19 from the side around the vertical axis, the tip of the drooping portion 21 And the folded portion 22 is formed by folding back from the notch 21a. After the folded portion 22 is formed, the presser 19 is retracted.
[0040]
Next, the third bending process is performed. In the tertiary bending process, as shown in FIG. 3 (e), a cylindrical presser 17B having a concave portion corresponding to the folded base at the tip is inserted into the concave groove 16a of the male mold 16 and folded. The portion 22 is pressed and joined integrally to the inside of the drooping portion 21, the lower surface side of the flange portion 20, and the outer peripheral surface of the outer pulp layer 2B. At the time of joining, it is preferable to use an adhesive such as starch because it can be more firmly integrated. In this way, the manufacture of the container 1 is completed.
[0041]
As described above, the container 1 of the present embodiment forms the hanging portion 21 on the peripheral edge portion of the flange portion 20 where the inner pulp layer 2A and the outer pulp layer 2B are joined, and further, the lower end portion of the hanging portion 21 is formed. The folded-back portion 22 is formed, and the folded-back portion 22 is integrally joined to the inner surface of the drooping portion 21, the back surface of the flat portion 20a, and the outer surface of the outer pulp layer 2B. When removing it when it is bonded to the part 20a or carrying it, the deformation of the flange part 20 is reliably suppressed, and also when the containers come into contact with each other during transportation, the resin film on the flange part is prevented from being damaged. Can do. Moreover, since the folding | returning part 22 is coat | covered with the resin film layer 3, and the edge part of the folding | returning part is arrange | positioned higher than the base part of folding | returning, the flooding to a flange part can be prevented reliably. Further, since the cut end portion of the flange portion 20 is not exposed to the outside, the mouth feel and appearance are good, and this is a preferable container in terms of hygiene.
[0042]
In addition, the container 1 of the present embodiment is formed by integrating the foaming agent layer 4 between the inner and outer pulp layers 2A and 2B, so that the container 1 is thin and excellent in heat insulation, and mechanical strength (compressed). Excellent strength. Furthermore, since the surface of the container 1 is smooth and there are no joints on the inner surface and the outer surface, the printability is good and the adhesiveness of the resin film is also good. In addition, the total layer thickness and the total layer density differ in the vertical direction of the body portion depending on the expansion ratio of the foaming agent, and the strength is increased by suppressing the expansion ratio in the vicinity of the flange portion 20 that does not require much heat insulation. It is an excellent container having high heat insulation and strength at necessary locations from the center to the bottom of the body where heat insulation is required by increasing the expansion ratio to increase heat insulation. In addition, the container 1 has excellent heat insulation properties and can be used as a container for high-temperature foods and drinks, and since it is difficult for condensation to occur on the surface, it can also be used as a container for cool foods and drinks. Needless to say.
[0043]
4 (a) to ( c ) Shows another embodiment of the flange portion in the container of the present invention. In these drawings, portions common to the container 1 of the above embodiment are given the same reference numerals and description thereof is omitted. Therefore, the description in the container 1 of the above embodiment is appropriately applied to points that are not particularly described.
[0044]
In the container of the embodiment shown in FIG. 4A, a drooping portion 21 that hangs downward from the peripheral edge portion is formed on the flange portion 20, and a folded portion 22 ′ that is folded upward from the lower end portion of the drooping portion 21. Is formed. The container of the present embodiment has the same effects as the container 1 and is particularly excellent in protecting the end surface because the end surface is inward.
[0045]
In the container of the embodiment shown in FIG. 4B, a hanging portion 21 that hangs downward from the peripheral edge portion is formed on the flange portion 20, and the folded portion is folded inward from the lower end portion of the hanging portion 21. A portion 22 ′ is formed, and the folded portion 22 ′ is joined to the inner surface of the hanging portion 21. The container of the present embodiment can obtain the same effect as the container 1, and, for example, when separating and discarding the film, the end of the film is in the vicinity of the lower bent portion. Easy to grip and peel.
[0046]
The container of the embodiment shown in FIG. 4 (c) has a hanging portion 21 that hangs downward from the peripheral edge portion of the flange portion 20 and is curved inwardly from the lower end portion of the hanging portion 21. The folded portion 22 'is formed by folding. The container of this embodiment has the same effect as the container 1 and is excellent in end face protection because the end face is inward.
[0049]
The container 1 and the container 1 ′ in FIGS. 4A to 4C can prevent water from entering from the tip without directly covering and protecting the tip of the folded portion with the resin film layer. This is an excellent form in that the step of winding the film can be omitted. Moreover, it is a container in which the prevention of water immersion is further improved by covering the tip of the folded portion with a resin film layer.
[0050]
The present invention is not limited to the above-described embodiment, and can be changed without departing from the spirit of the present invention.
[0051]
For example, the resin layer is preferably formed of a resin film in the case of a container having a wide diameter as in the container 1 of the above embodiment, but can also be formed by applying a paint containing a resin. As such paints, general-purpose waterproof and moisture-proof paints can be used, and in particular for food containers for instant cup noodles, acrylic resin emulsion paints are used when heat resistance is required. be able to. The choice of whether the resin layer is formed of a resin film or by applying a paint depends on the shape of the container, such as a deep container or a container having a constricted part, and the barrier characteristics required depending on the purpose of use of the container Etc. can be appropriately performed.
[0052]
Further, as in the container 1 of the above-described embodiment, in the case of a cup-shaped container, a part having a different total layer thickness and total density is formed in the body part (gripping part) 23 according to the foaming ratio of the foaming agent. It is preferable, but the part where the total layer thickness and the total density differ depending on the expansion ratio of the foaming agent can be appropriately set according to the shape of the container, for example, when the shape of the container is a dish-shaped container Can be formed in other parts such as the trunk and the bottom. Moreover, although it is preferable to form a stack in the trunk | drum 23, a stack can also be abbreviate | omitted as needed.
[0053]
The container of the present invention preferably includes a heat insulating layer composed of the foaming agent layer 4 as in the above-described embodiment, but the heat insulating layer may be formed by providing a gap in the outer pulp layer 2B and the inner pulp layer 2A. it can. Moreover, a heat insulation layer can also be abbreviate | omitted according to the use of a container. Furthermore, the papermaking container main body 2 can also be formed from a single layer of pulp.
[0054]
As described above, the container of the present invention is preferably manufactured by previously drying and densifying the outer pulp layer 2B and then superimposing it with the inner pulp layer 2A and combining them together. Can be manufactured by superimposing the inner pulp layer on the inner pulp layer without drying in advance, and then drying both.
[0055]
Moreover, the method of coat | covering the outer surface of 2 A of inner pulp layers with a foaming agent immerses the outer surface of an inner pulp layer in the liquid containing a foaming agent as mentioned above, and this liquid is applied to the outer surface of 2 A of inner pulp layers. Although it is preferable to perform the impregnation, the liquid can be coated on the outer surface of the inner pulp layer 2A by spray coating or the like.
Moreover, in the manufacturing method of the container of the said embodiment, although the resin film was formed after performing a primary bending process, a primary bending process can also be performed after forming a resin film layer.
[0056]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
A container having the following dimensions and shape in the form shown in FIG. 1 was produced as follows.
[0057]
<Container shape>
Height H: 110mm
Opening inner diameter φ1: 88mm
Bottom outer diameter φ2: 70mm
Flange part flat part width W: 1.3mm
Flange flat portion thickness T: 1.6 mm
Hanging height H1: 3.0mm
Upper part thickness T1: 0.8mm
Body center thickness T2: 1.5 mm
Lower trunk thickness T3: 2.0 mm
Bottom thickness T4: 1.0 mm
Corner radius of curvature: R1 = 1mm, R2 = 1.5mm
[0058]
<Paper making of inner and outer pulp layers>
A male mold provided with a silicone rubber papermaking part corresponding to each inner and outer pulp layer of the container and a nylon net (50 mesh, wire diameter 100 μm) covering the papermaking part is immersed in a slurry having the following composition, A pulp layer was formed.
Slurry for outer pulp layer;
Pulp slurry: (pulp fiber (virgin pulp: imitation waste paper = 3: 7 (weight ratio), pulp slurry concentration 0.5% by weight))
Sizing agent (2% by weight of pulp)
Slurry for inner pulp layer;
Pulp slurry: (pulp fiber (virgin pulp: imitation waste paper = 3: 7 (weight ratio), pulp slurry concentration 0.5% by weight))
Sizing agent (2% by weight of pulp)
[0059]
<Dehydration and drying conditions of outer pulp layer>
The outer pulp layer was disposed between the female mold corresponding to the male mold, and dehydrated and dried under pressure under the following conditions. Moreover, the starch paste was apply | coated to the site | part corresponding to the flange part of the outer pulp layer after drying.
Mold temperature: 200 ℃
Pressing force: 0.4 MPa (180 seconds)
[0060]
<Coating with foaming agent on outer surface of inner pulp layer>
The inner pulp layer was immersed in a foaming agent-containing liquid having the following composition, and the outer surface of the trunk portion of the inner pulp layer was impregnated with the foaming agent.
Foaming agent-containing liquid;
Water containing 1% by weight of foaming agent (Matsumoto Oil Pharmaceutical Co., Ltd. [Matsumoto Microsphere-F82]: foaming temperature of 160 to 170 ° C.) 5% by weight based on the total weight of the molded product)
[0061]
<Heating and drying conditions>
After superposing the inner and outer pulp layers, they were dried under the following mold temperature and pressure to foam the foaming agent and to integrate both pulp layers.
Mold temperature: 200 ℃
Pressing force: 0.4 MPa (180 seconds)
[0062]
<Cutting>
The peripheral edge of the flange portion of the container was cut by punching with a punching blade having an inner diameter of 107 mm.
[0063]
<Primary bending>
The flange portion was bent under the following conditions to form a hanging portion.
Surface temperature of the presser (aluminum): 50 ° C
Male mold (aluminum) surface temperature: 110 ° C
Pressing force: 3tonf
[0064]
<Formation of resin film layer>
The following resin films were placed so that the inner layer was in contact with the inner pulp layer, and laminated under the following molding conditions. And the excess film was cut | disconnected in the edge part of a pulp layer after lamination | stacking.
Resin film;
Outer layer / inner layer = high density polyethylene / low density polyethylene
Resin film layer thickness: 150 μm
Molding condition;
Vacuum forming machine: Sanwa Kogyo brand name PLAVAC-FE36PHS
Film heating method: Infrared heater (space between heater and resin film 110mm)
Film heating temperature: 250 ° C (molding machine display temperature)
Film heating time: 35 seconds
Plug dimensions: 60mm diameter x 110mm length
Plug material: Aluminum (Teflon processing on the surface)
Plug temperature: 115 ° C (plug actual surface temperature)
Vacuum forming mold: mouth hole diameter φ88mm, bottom diameter φ70mm, height 110mm
Mold temperature for vacuum forming: 115 ° C (actual surface temperature inside the mold)
Molding time: 15 seconds
[0065]
<Secondary bending>
The folded portion was bent under the following conditions.
Hot air temperature: 120 ° C
Male mold (aluminum) surface temperature: normal temperature
[0066]
<Third bending>
The pressing was performed under the following conditions and the male mold was heated or hot air was blown to press the folded portion and integrally joined to the inner surface of the hanging portion, the rear surface of the flange portion, and the outer surface of the outer pulp layer.
Presser (aluminum) surface temperature: 110 ° C
Male (aluminum) surface temperature: 110 ° C
Hot air temperature: 120 ° C
Applied pressure 100kgf
[0067]
[Measurement of thickness and total thickness of each layer]
Partial fragments were cut out from the molded body, and the thickness of each layer was measured with a tool microscope.
[0068]
[Measurement of density of each layer]
The density of the foaming agent layer and the inner pulp layer was calculated based on the thickness, the area of the cut piece, the weight thereof, the total weight of the molded body, and the weight of the foaming agent.
[0069]
(Evaluation of thermal insulation properties)
Pour hot water of 95 to 100 ° C. into the container 1, measure the temperature of the hot water in the container after 3 minutes and the temperature of the outer surface of the container with a contact thermometer, and determine the temperature of the hot water and the temperature of the outer surface of the container. The temperature difference was determined.
[0070]
[Measurement of inner surface smoothness]
Surfcom 120A (manufactured by Tokyo Seimitsu Co., Ltd.) was used to measure the surface roughness, and the measurement conditions were cut-off: 2.5 mm, measurement length: 10.00 mm, filter: 2CR, measurement magnification: 500, inclination Correction: straight line, polarity: standard.
[0071]
The container thus produced had a desired strength at the flange portion, could prevent water from entering from the end of the flange portion, and had a good appearance.
In addition, the total thickness is 0.8 to 5 mm, it is thin and lightweight, and it has good heat insulation, so that even when hot water is poured, the container can be directly gripped, and shape retention is maintained at that time. It was a thing. Also, surface smoothness is high, centerline average roughness Ra is 1 to 20 μm, maximum height Rmax is 100 μm or less, resin film has good adhesion, no pinholes, and good printability on outer surface Met.
[0072]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the desired intensity | strength can be provided to a flange part, the flooding from the edge part of a flange part can be prevented, and a container with a favorable external appearance is provided.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an embodiment of a container according to the present invention, in which (a) is a schematic plan view, and (b) is an enlarged sectional view of a flange portion.
FIG. 2 is a schematic view showing a part of the manufacturing process of the container of the present invention, wherein (a) shows a paper making process of the outer pulp layer, and (b) shows a dehydration / drying process of the outer pulp layer. (C) is a figure which shows the paper making process of an inner pulp layer, (d) is a figure which shows the process which coat | covers the outer surface of an inner pulp layer with a foaming agent, (e) is an inner pulp layer and an outer pulp layer (F) is a figure which shows a drying process.
3A and 3B are schematic views showing a part of the manufacturing process of the container of the present invention, wherein FIG. 3A is a view showing a cutting process, FIG. 3B is a view showing a primary bending process, and FIG. 3C is a resin film layer; The figure which shows the formation process of this, (d) is a figure which shows a secondary bending process, (e) is a figure which shows a tertiary bending process.
FIG. 4 (a) to ( c ) Is a schematic cross-sectional view (corresponding to FIG. 1 (b)) of the main part showing another form of the flange portion in the container of the present invention.
[Explanation of symbols]
1 container
2 Paper container body
2A Inner pulp layer
2B outer pulp layer
20 Flange
21 Hanging part
22 Folding part
3 Resin film layer
4 Blowing agent layer

Claims (3)

In a container provided with a resin layer that covers the inner surface of the papermaking container main body having a flange part at the periphery of the opening end part and the flange part,
The flange portion has a hanging portion that hangs downward from the peripheral portion thereof,
The hanging portion has a folded portion folded inward from the lower end portion thereof,
The distal end of the folded portion is disposed at a position higher than the folded base, the distal end portion is concealed by the hanging portion, and the outer surface portion and the lower end portion of the hanging portion are covered with the resin layer. container. The folded portion is extended to a lower flat portion of the inner or the flange portion of the hanging portion and the hanging lower portion of the inner surface or claim 1, wherein are integrally joined to the rear surface of the flat portion of the flange portion Container. The container according to claim 1 or 2 , wherein the resin layer is formed of a film.

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