JP2009035309A - Paper resin compound sheet, paper resin compound integrally formed container, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper resin compound sheet and a paper resin compound integrally formed container mainly consisting of paper, easily disposed of, excellent in appearance and formability, and capable of preventing any leakage of soup therefrom, and to provide a manufacturing method thereof. <P>SOLUTION: The paper resin compound integrally formed container 1 has a base part 2 formed of a paper resin compound sheet having a resin layer at least on one side of a paper layer, and a recessed part 3 formed of the paper resin compound sheet which is integrally pressed continuously from the base part 2. Weakened parts 6, 7, etc. for permitting the stretching deformation of the resin layer by weakening the strength of the paper layer are formed at least at a part of the base part 2 or the recessed part 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention is mainly used for applications such as lunch box containers and confectionery / food packaging, and is used for forming a container having a depth or having a partition. Regarding the method.

Various foods are distributed due to diversification of eating habits, and are produced and sold in large quantities, such as convenience stores and food-related manufacturing industries. Disposable containers are widely used for applications. The current material is mainly plastic because of its ease of molding into a container shape, but there is a problem that disposal is not easy.
In recent years, due to the increase in environmental awareness and the enactment of the Containers and Packaging Recycling Law, businesses and consumers are becoming more aware of container and packaging disposal issues. For this reason, paper containers that can be discarded as combustible materials have attracted attention.

Paper containers have the advantage that they can be disposed of as flammables, but the general elongation of paper is 2-5%, which is extremely low compared to plastics. It was the best to use it as a dish. Moreover, in the lunch box container, it is necessary to partition not only the depth but also the inside of the container. Conventionally, when a lunch box is made of a paper material, the container body is formed by a folding method, and a separate part is prepared for the partition plate. However, this not only takes time and labor for assembly, but if the contents are soup, the leaked soup is not stopped by the partition, and the adjacent ingredients are soiled.
For example, as described in Patent Documents 1 and 2, several assemblable paper containers have been proposed, but these require a lot of labor for manufacturing due to the complexity of the assembly structure, and the vertical and horizontal directions. The combination of partitions requires separate partition plate parts, and these containers are insufficient in preventing leakage of the juice from the partitions.
In view of this, a method of integrally forming by drawing using an elongated paper having a higher elongation rate than general paper has been developed.
Japanese Patent No. 3817800 JP 2004-333121 A

  However, special paper, such as stretched paper, is expensive, and complex shapes with height and partitions, such as a container for lunch boxes, are difficult to mold even with stretched paper with a high elongation rate, and multiple folds are possible. Thus, there are problems that the aesthetic appearance is impaired and the paper layer breaks during the molding.

  The present invention has been made in view of the above circumstances, and is a paper resin composite sheet and paper resin composite integrated container that are mainly made of paper, are easy to dispose, have good aesthetics and moldability, and do not leak juice. And it aims at providing the manufacturing method.

  In order to solve the above-mentioned problem, the present inventor has intensively studied. As a result, even when the paper resin composite integrally molded container using stretched paper breaks during the molding, the paper layer is covered. It was found that the resin layer that remains is often left unbroken. Therefore, it was found that the breakage can be controlled by covering the resin layer with a weakening part that weakens the strength, such as perforations, slits, cuts, etc., in advance in the paper layer of the part that is easily broken. I came to let you. That is, the present invention has the following configuration.

(1) The paper resin composite sheet of the present invention includes a resin layer on at least one surface of the paper layer, and a weakened portion that weakens the strength of the paper layer and allows stretching deformation of the resin layer is formed in the paper layer. It is characterized by.
(2) A paper resin composite integrally molded container of the present invention has a base portion made of the above-mentioned paper resin composite sheet, and a concave portion made of the paper resin composite sheet that is integrally press-molded continuously from the base portion. The weakened portion is formed in at least a part of the base portion or the concave portion.
(3) In the paper resin composite integrally formed container of the present invention, a rupture portion is formed in a part of the paper layer starting from the formation position of the weakened portion, and the resin layer is stretched through the rupture portion. It is preferable that the recess is formed.
(4) In the paper resin composite integrally molded container of the present invention, it is preferable that a plurality of the recesses are formed and a partition wall is provided between the recesses.
(5) In the paper resin composite integrally molded container of the present invention, it is preferable that the weakening portion is formed at a boundary portion between the bottom surface and the wall surface of the concave portion and / or a boundary portion between the base portion and the wall surface.
(6) In the paper resin composite integrally molded container of the present invention, it is preferable that the shape of the cross section of the concave portion is substantially circular, and the weakened portion is formed radially from the center of the concave portion on the wall surface. .
(7) In the paper resin composite integrally molded container of the present invention, it is preferable that the cross section of the concave portion has a square shape, and the weakened portion is formed at a corner portion of the wall surface.
(8) The method for producing the paper resin composite integrally formed container of the present invention includes a step of forming a weakened portion that weakens the strength in the paper layer;
Forming a resin layer on at least one surface of the paper layer on which the weakened portion is formed to form a composite sheet;
A step of integrally pressing the paper layer and the resin layer to form a recess,
In the step of integrally forming the concave portion by press molding, a fracture portion of the paper layer starting from the weakened portion is formed at any of a boundary portion between the bottom surface and the wall surface of the concave portion, the bottom surface, and the wall surface. However, the composite sheet is stretched to form the recess.
(9) The method for producing a paper resin composite integrally molded container of the present invention includes a step of forming a resin layer on at least one surface of the paper layer;
Forming a weakened portion that weakens the strength of the paper layer on which the resin layer is formed;
A step of integrally pressing the paper layer and the resin layer to form a recess,
In the step of integrally forming the concave portion by press molding, a fracture portion of the paper layer starting from the weakened portion is formed at any of a boundary portion between the bottom surface and the wall surface of the concave portion, the bottom surface, and the wall surface. However, the composite sheet is stretched to form the recess.

  According to the paper resin composite sheet of the present invention, at least one surface of the paper layer is provided with a resin layer, and a weakened portion that weakens the strength of the paper layer and allows stretching deformation of the resin layer is formed on the paper layer. Therefore, the breakage of the paper layer at the time of molding can be eased, and even if the breakage occurs, the place where the weakened part is put is preferentially broken, so the aesthetic appearance is not impaired, and the breakage part of the paper layer Since it is covered with layers, it can be formed into a container shape without breaking as a composite sheet. Therefore, paper with low elongation can be used, and the part to be broken is calculated and arranged in advance, so that it can be integrally molded even in a container shape with a severely stretched part such as a partition wall. is there.

  According to the paper resin composite integrally molded container of the present invention, the paper resin composite sheet has a base portion and the concave portion made of the paper resin composite sheet that is integrally press-molded continuously from the base portion. The weakened portion is formed on at least a part of the base or the concave portion, so that the breakage of the paper layer at the time of molding can be relieved, and the place where the weakened portion is inserted takes priority even if the breakage occurs. Therefore, the rupture portion of the paper layer is covered with the resin layer, so that it can be formed into a container shape without rupture as a paper resin composite integrally formed container. Therefore, paper with low elongation can be used, and the part to be broken is calculated and arranged in advance, so that it can be integrally molded even in a container shape with a severely stretched part such as a partition wall. Yes, the obtained container is excellent in water resistance, and if PET (polyethylene terephthalate), PP (polypropylene) or PBT (polybutylene terephthalate) is used as the resin layer, a container excellent in oil resistance and heat resistance can be obtained. The use of a range is also possible, and PET and PBT with particularly high heat resistance can also be used in an oven range.

  Further, according to the paper resin composite integrally molded container of the present invention, a rupture portion is formed in a part of the paper layer starting from the formation position of the weakened portion, and the resin layer is stretched through the rupture portion. By forming the concave portion, it is possible to disperse the force applied to the severe stretch-molded portion, and to further alleviate the break at the time of integral press molding, thereby increasing the effect of controlling the break.

  Further, according to the paper resin composite integrally formed container of the present invention, a plurality of the recesses are formed, and by having a partition wall between the recesses, it is convenient to accommodate a plurality of foodstuffs such as a lunch box container, If a partition wall having a sufficient partition and height is provided, the leaked juice does not flow into the adjacent recesses, and there is no risk of contaminating other ingredients.

  Moreover, according to the paper resin composite integrally molded container of the present invention, the weakened portion is easily broken because it is formed at the boundary between the bottom surface and the wall surface of the concave portion and / or the boundary portion between the base portion and the wall surface. Since the strength of the paper layer at the boundary is weakened, it is possible to reduce breakage during integral press molding. In addition, even if breakage occurs, the place where the weakened portion is inserted breaks preferentially, so the appearance is not impaired, and the broken portion of the paper layer is covered with the resin layer, so there is no breakage as a base material It can be formed into a container shape.

  Further, according to the paper resin composite integrally molded container of the present invention, the shape of the cross section of the recess is substantially circular, and the weakened portion is formed radially from the center of the recess on the wall surface. Since the strength of the paper layer on the wall surface that is easy to break is weakened, breakage during molding can be eased. In addition, even if breakage occurs, the place where the weakened portion is inserted breaks preferentially, so the appearance is not impaired, and the broken portion of the paper layer is covered with the resin layer, so there is no breakage as a base material It can be formed into a substantially circular container shape.

  According to the paper resin composite integrally molded container of the present invention, the shape of the cross section of the concave portion is square, and the weakened portion is formed at the corner of the wall surface, so that the corner easily breaks. Since the strength of the paper layer is weakened, breakage during molding can be eased. In addition, even if breakage occurs, the place where the weakened portion is inserted breaks preferentially, so the appearance is not impaired, and the broken portion of the paper layer is covered with the resin layer, so there is no breakage as a base material It can be formed into a rectangular container shape.

  According to the method for producing a paper resin composite integrally formed container of the present invention, a step of forming a weakened portion that weakens the strength of the paper layer, and a resin layer is formed on at least one surface of the paper layer on which the weakened portion is formed. A step of forming a concave portion by integrally press-molding the paper layer and the resin layer, and forming the concave portion by integrally press-molding the concave portion. Forming the concave portion by stretching the composite sheet while forming a fracture portion of the paper layer starting from the weakened portion at any of the boundary between the bottom surface and the wall surface, the bottom surface, and the wall surface The break at the time can be eased, and even if the break occurs, the place where the weakened portion is put is preferentially broken so that the appearance is not impaired, and the broken portion of the paper layer is covered with the resin layer, Container shape without breaking as a substrate It is possible to form.

  Further, according to the method for producing a paper resin composite integrally formed container of the present invention, a step of forming a resin layer on at least one surface of the paper layer, and a weakened portion that weakens the strength are formed on the paper layer on which the resin layer is formed. And a step of integrally pressing and forming the paper layer and the resin layer to form a recess, and in the step of integrally pressing and forming the recess, a bottom surface and a wall surface of the recess Rupture at the time of molding by forming the concave portion by stretching the composite sheet while forming a fracture portion of the paper layer starting from the weakened portion at any of the boundary portion, the bottom surface, and the wall surface Even if breakage occurs, the place where the weakened part is inserted breaks preferentially, so there is no loss of aesthetics, and the broken part of the paper layer is covered with a resin layer, so as a base material Molded into a container shape without breaking It is possible.

  In any of the above-mentioned methods for manufacturing a paper resin composite integrally molded container, a paper having a small elongation can be used, and a severely molded part such as a partition wall is obtained by preliminarily calculating and arranging the breaking points. Integral press molding is possible even in the shape having The obtained container is excellent in water resistance, and if a partition wall having a sufficient partition and height is provided, the leaked juice will not contaminate other ingredients. In addition, if PET, PP, or PBT is used as the resin layer, a container having excellent oil resistance and heat resistance can be obtained, and a microwave oven can be used. Especially, PET and PBT having high heat resistance can be used in a microwave oven. It is also possible to do.

Embodiments of the present invention will be described below in detail with reference to the drawings.
As shown in FIGS. 1 to 8, the paper resin composite integrally molded container of the present invention includes a resin layer on at least one surface of the paper layer, weakening the strength of the paper layer and allowing stretching deformation of the resin layer. However, a paper resin composite sheet (hereinafter abbreviated as a composite sheet) formed on the paper layer is used. The composite sheet has a base part and a concave part made of the composite sheet that is integrally press-formed continuously from the base part, and the weakened part is formed in at least a part of the base part or the concave part. It is characterized by.

<First Embodiment>
1 and 2 show a paper resin composite integrally formed container (confectionery tray) 1 according to a first embodiment of the present invention.
As shown in FIG. 1, FIG. 2 (A), (B), the confectionery tray 1 is composed of a composite sheet S having a resin layer on at least one surface of a paper layer, and an outer frame (base) 2 is square and has sides. The four concave portions 3,... Are symmetrically formed in a square region that is equally divided into four at the center line. Each recess 3 has a circular cross section, and includes a bottom surface 4 and a wall surface 5, and the wall surface 5 is formed with a slight inclination so that the cross section spreads upward from the bottom surface 4. A circular weakened portion 6 is formed at the boundary between the bottom surface 4 and the wall surface 5, and the weakened portion 7 made up of perforations, V-grooves, ruled lines, etc., is radially spaced from the center of the concave portion 3 on the wall surface 5. Are formed in a cross shape as viewed in a plan view as shown in FIG. 2 (A) by the wall surfaces 5,... Between the recesses 3,. As shown, a partition wall 8 having an inverted V-shaped longitudinal section is formed.

As shown in FIG. 2 (C), the composite sheet S on which the confectionery tray 1 is formed is made of a composite material having a resin layer 2b on the inner surface of the paper layer 2a, and these weakened portions 6, 7,. Formed on the paper layer 2a and covered with the resin layer 2b. Further, as shown in FIG. 2D, a resin layer 2c may be further formed on the outer surface of the paper layer 2a, and may be covered on both sides.
In any case, the weakened portions 6, 7,... Are formed only in the paper layer 2a, and the broken portions of the weakened portions 6, 7,... Are covered with the resin layer 2b or the resin layers 2b, 2c.
The weight ratio of the paper layer is preferably 50% or more, and can be displayed as a paper container within this range.

Second Embodiment
FIG. 3 shows a paper resin composite integrally formed container (confectionery tray) 1A according to the second embodiment of the present invention.
As shown in FIG. 3 (A), the confectionery tray 1A is composed of a composite sheet S having a resin layer on at least one side of a paper layer. The outer frame (base) 1a is rectangular and has a long bisector and a short side. Six recesses 3A,... Are formed in a grid-like position in a rectangular region that is equally divided into six by the center line of the side. Each recess 3A has a square cross section, and includes a bottom surface 4A and a wall surface 5A. The wall surface 5A is formed with a slight inclination so that the cross section expands upward from the bottom surface 4A. A weakened portion 6A similar to the shape of the bottom surface 4A is formed at the boundary between the bottom surface 4A and the wall surface 5A, and weakened portions 7A,... Are formed at the corners of the wall surface 5A, respectively. .. And the upper surface sandwiched between the wall surfaces 5A,... Form a partition wall 8A having an inverted V-shaped longitudinal section as shown in FIG.

As shown in FIG. 2 (C), the composite sheet S on which the confectionery tray 1A is formed is made of a composite material having a resin layer 2b on the inner surface of the paper layer 2a, and these weakened portions 6A, 7A,. Formed on the paper layer 2a and covered with the resin layer 2b. Further, as shown in FIG. 2D, a resin layer 2c may be further formed on the outer surface of the paper layer 2a, and may be covered on both sides.
In any case, the weakened portions 6A, 7A,... Are formed only on the paper layer 2a, and the broken portions of the weakened portions 6A, 7A,... Are covered with the resin layer 2b or the resin layers 2b, 2c.

<Third Embodiment>
4 and 5 show a paper resin composite integrally molded container (lunch container) 11 according to a third embodiment of the present invention.
As shown in FIGS. 4 (A), 5 (A), and 5 (B), the container 11 for lunch box has four outer frames (base portions) 11a in a region in which the rectangle is rectangular and the rectangle is divided into four by a cross. Recesses 12, 13, 14, and 15 are formed. The cross sections of the recesses 12, 13, 14, and 15 are square shapes having different shapes and shapes, and each has a bottom surface 16, 17, 18, 19 and wall surfaces 20, 21, 22, and 23. The wall surfaces 20, 21, 22, and 23 are formed with a slight inclination so that the cross section spreads upward from, 17, 18, and 19. Weak portions 24, 25, 26 and 27 similar to the shape of the bottom surfaces 16, 17, 18, and 19 are formed at the boundaries between the bottom surfaces 16, 17, 18, and 19 and the wall surfaces 20, 21, 22, and 23. The weakened portions 28, 29, 30, 31 are formed vertically at the corners of the portions 20, 21, 22, 23, and the wall surfaces 20, 21, 22, 23 between the recesses 12, 13, 14, 15, The upper surface between the wall surfaces 20, 21, 22, and 23 has a cross-shaped plan view as shown in FIG. 5 (A), and the vertical cross-section of the partition wall 32 as shown in FIG. 5 (B). Is formed.
Further, as shown in FIG. 4B, in the lunch box container 11A having the same shape as the lunch box container 11, the weakened portions 33, 34, 35, and 36 are formed in a horizontal line shape so as to divide the center of the wall surface. May be.
When the paper layer breaks, the broken portion becomes only the resin and becomes weak in strength. However, when the weakened portions 33, 34, 35, and 36 are provided in such portions, the wall surfaces 20a, 21a, Since the central portions of 22a and 23a can be intentionally broken, the bottom surfaces 16a, 17a, 18a, and 19a and the wall surfaces 20a, 21a, 22a, and 23a, which are portions where force concentrates when used as the lunch box 11A, are used. Can be prevented from breaking, and a decrease in strength as the lunch box 11A can be minimized.

As in the first embodiment, the lunch box containers 11 and 11A are composed of a composite sheet S having a resin layer on at least one surface of the paper layer. As shown in FIG. 2C, the resin layer is formed on the inner surface of the paper layer 2a. 2b may be coated, or, as shown in FIG. 2D, a resin layer 2c may be further formed on the outer surface of the paper layer 2a, and may be coated on both surfaces.
In any case, the weakened portions 24 to 36 are formed only on the paper layer 2a, and the broken portions of the weakened portions 24 to 36 are covered with the resin layer 2b or the resin layers 2b and 2c.

<Fourth embodiment>
6 and 7 show a paper resin composite integrally molded container (a bun tray) 51 according to a fourth embodiment of the present invention.
As shown in FIG. 6 and FIG. 7 (A), the wharf tray 51 is composed of a composite sheet S having a resin layer on at least one surface of the paper layer, and the outer frame (base) 51a is square and is divided into three equal parts. Nine concave portions 53,... Are formed in a lattice shape in a square region equally divided by lines. Each recess 53 has a square cross section, and includes a bottom surface 54 and a wall surface 55. The wall surface 55 is formed with a slight inclination so that the cross section expands upward from the bottom surface 54. A weakened portion 56 similar to the shape of the bottom surface 54 is formed at the boundary between the bottom surface 54 and the wall surface 55, and weakened portions 57,... Are formed at the corners of the wall surface 55, respectively. .. And the upper surface sandwiched between the wall surfaces 55,..., In a plan view lattice shape as shown in FIG. 7 (A), and a vertical cross section as shown in FIG. An inverted V-shaped partition wall 58 shallower than the above is formed.

As shown in FIG. 2C, the composite sheet S on which the confectionery tray 51 is formed is made of a composite material having a resin layer 2b on the inner surface of the paper layer 2a, and these weakened portions 56, 57,. Formed on the paper layer 2a and covered with the resin layer 2b. Further, as shown in FIG. 2D, a resin layer 2c may be further formed on the outer surface of the paper layer 2a, and may be covered on both sides.
In any case, the weakened portions 56, 57,... Are formed only on the paper layer 2a, and the broken portions of the weakened portions 56, 57,... Are covered with the resin layer 2b or the resin layers 2b, 2c.

<Fifth Embodiment>
FIG. 8 shows a paper resin composite integrally formed container (cup) 61 according to the fifth embodiment of the present invention.
As shown in FIG. 8, the cup 61 is made of a composite sheet S having a resin layer on at least one surface of a paper layer, and has a recess 63 formed by a cylindrical wall surface 65 and a circular bottom surface (base) 64. Have. A circular weakened portion 66 is formed at the boundary between the bottom surface 64 and the wall surface 65, and a weakened portion 67 is formed vertically on the wall surface 65.

As shown in FIG. 2C, the composite sheet S on which the cup 61 is formed is made of a composite material having a resin layer 2b on the inner surface of the paper layer 2a. 2a and covered with a resin layer 2b. Further, as shown in FIG. 2D, a resin layer 2c may be further formed on the outer surface of the paper layer 2a, and may be covered on both sides.
In either case, the weakened portions 66 and 67 are formed only on the paper layer 2a, and the broken portions of the weakened portions 66 and 67 are covered with the resin layer 2b or the resin layers 2b and 2c.

The points common to the first to fifth embodiments will be described below.
"Weakening part"
The shape of the weakened portion is not particularly limited as long as the strength of the paper layer in the weakened portion is weaker than other portions, such as perforations, slits, cuts, and ruled lines. For example, as shown in FIG. 9, a composite sheet in which the paper layers 70, 71,... Of each part constituting the container are completely divided and the paper layers 70, 71,. S ′ may be formed into a container shape by drawing or the like.
The weakened portion may be formed in a severely molded portion in accordance with the shape of the container or the recess, and may be one or a plurality of locations, and the portion is not particularly limited. For example, it is preferably formed in a portion that is easily broken, such as a boundary portion between a bottom surface and a wall surface of a concave portion having a container shape.
By forming the weakened portion in this way, it is possible to relieve breakage during molding, and even if breakage occurs, the place where the weakened portion is put is preferentially broken, so that the appearance is not impaired, and the paper layer Since the broken portion is covered with the resin layer, it can be formed into a container shape without being broken as a base material. For this reason, paper having a small elongation can be used, and the portion to be broken is calculated and arranged in advance, so that even a shape having a severely shaped part such as a partition wall can be integrally formed.

"Container shape"
Although the shape of the container is not particularly limited, the lattice-shaped mold shown in FIGS. 6 and 7, such as the substantially circular shape shown in FIGS. 1 and 2, the square shape shown in FIG. 3, and the odd-shaped mixed type shown in FIGS. For example, it may be formed in a general container shape.
Since the present invention is mainly used for applications such as lunch box containers and confectionery / food packaging, it is preferable that two or more recesses are formed, and a partition wall is provided between the recesses, and three or more recesses are formed. It is more preferable. By doing so, it is convenient to accommodate a plurality of ingredients such as a lunch box, and if a partition wall having a sufficient partition and height is provided, the leaked juice does not flow into the adjacent recesses, There is no risk of contaminating other ingredients.
However, the concave portion may be a single container or may be a vertically long shape such as a cylindrical shape as shown in FIG.

"Partition wall"
It is preferable that the angle of a partition wall is formed in the range of 60-90 degrees. If the angle of the partition wall is less than 60 °, it becomes close to a shallow dish shape, so that the height is not sufficiently formed, and if it exceeds 90 °, the wall surface becomes wider than the opening and molding is difficult.
The height of the partition wall is preferably in the range of 30 to 150% of the peripheral wall. If the height of the partition wall is less than 30% of the peripheral wall, the leaked juice tends to flow into the adjacent recesses and may contaminate other ingredients. Moreover, when the height of a partition wall exceeds 150%, it will become higher than a surrounding wall, and shaping | molding will be difficult.

"paper"
The type of paper used for the paper layer is not particularly limited. Specifically, high-quality paper, thin paper, craft paper, coated paper, paperboard, cardboard paper, Japanese paper, and the like can be used.
The basis weight is preferably from 30 to 500 g / ^{m 2,} more preferably from 80~360g / ^{m 2.} If the basis weight is less than 30 g / m ² , the container is too thin and the strength of the container is insufficient, and if it exceeds 500 g / m ² , the paper is too thick and molding is difficult.
The balance with the film made of the resin layer is, for example, about 10 to 40 μm, preferably about 15 to 30 μm, with respect to the basis weight of 150 g / m ² .

"resin"
The resin used for the resin layer can be selected from PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), etc., but particularly from the viewpoints of moldability, heat resistance, oil resistance, etc. PP, PET, and PBT are preferable, and since the mold generally used for press working is 50 to 150 ° C., these films do not melt. Furthermore, PET and PBT having heat resistance up to 220 to 230 ° C. are more preferable.
The resin layer may be a film or an extrusion laminate, and is not particularly limited.
The resin layer is formed on one or both sides of the paper layer, and the total film thickness is preferably in the range of 20 to 100 μm. If the film thickness is less than 20 μm, it is too thin and it is difficult to maintain the shape of the paper breakage portion, and even if it exceeds 100 μm, there is no difference in the effect obtained.
A container provided with such a resin layer is excellent in water resistance. If PET, PP, or PBT is used as the resin layer, a container having excellent oil resistance and heat resistance can be obtained, and a microwave oven can be used. Especially, PET and PBT having high heat resistance should be used in a microwave oven. Is also possible.

"Molding method"
Although the molding method of the paper resin composite integrally molded container according to the first to fifth embodiments described above is not particularly limited, it can be mainly molded by press molding.
Then, the manufacturing method of the paper resin composite integral molding container of this invention is demonstrated.

The method of manufacturing a paper resin composite integrally molded container according to the present invention includes a step of forming a weakened portion that weakens strength in a paper layer, and a resin layer formed on at least one surface of the paper layer on which the weakened portion is formed. The sheet is roughly composed of a step of forming a concave portion by integrally press-molding the paper layer and the resin layer.
In addition, the method for producing a paper resin composite integrally molded container of the present invention forms a resin layer on at least one surface of a paper layer, then forms a weakened portion that weakens the strength on the paper layer, and integrally stretches the paper layer and the resin layer. You may perform the process of shape | molding and forming a recessed part.

In the step of forming the recess, for example, a press working apparatus 100 as shown in FIG. 10 is used.
The press working apparatus 100 sandwiches the composite sheet S and presses a mold 101 that presses from the inside of the container shape, a mold 102 that presses the outside of the bottom surface, a mold 103 that presses from the outside of the mold 102, and a mold on which the mold 101 is placed. The mounting base 104, the mold 105 that presses from the inside of the outer periphery of the container shape, the mold 106 that presses the outer periphery, the protrusion 107 that surrounds the outer periphery of the composite sheet S, the base 108 on which the mold 105 is placed, and the base 108 And an attached piston 109.
When the composite sheet S is sandwiched and pressed between these molds 101, 102, 103, 105, 106, a shape having a recess as shown in FIG. 11 (b) in a planar shape as shown in FIG. 11 (a). Can be formed. At this time, the composite sheet S is stretched to form a recess while forming a fracture portion of the paper layer starting from the weakened portion at any of the boundary between the bottom surface and the wall surface of the recess, the bottom surface, and the wall surface.

  By processing in this way, the break at the time of molding can be relieved, and even if breakage occurs, the place where the weakened part is inserted preferentially breaks, so the aesthetic appearance is not impaired, and the broken part of the paper layer is Since it is covered with the resin layer, it can be formed into a container shape without breaking as a base material. For this reason, paper having a small elongation can be used, and the portion to be broken is calculated and arranged in advance, so that even a shape having a severely shaped part such as a partition wall can be integrally formed.

For finishing, by operating the mold part of the projecting portion 107 with the piston 109, it can be molded as shown in FIG. 11 (d), and the outer peripheral portion S1 can be further rounded.
In addition, wax or the like may be applied to the composite sheet S so that it can be easily processed during pressing.
The container thus obtained is excellent in water resistance, and if a partition wall having a sufficient partition and height is provided, the leaked juice will not contaminate other ingredients. In addition, if PET, PP, or PBT is used as the resin layer, a container having excellent oil resistance and heat resistance can be obtained, and a microwave oven can be used. Can also be used.

FIG. 1 is a perspective view of a paper resin composite integral-molded container according to a first embodiment of the present invention. 2A is a plan view of the paper resin composite integrally molded container shown in FIG. 1, FIG. 2B is a cross-sectional view, and FIGS. 2C and 2D are cross-sectional views of the composite sheet. FIG. 3A is a plan view of a paper resin composite-integrated container according to the second embodiment of the present invention, and FIG. 3B is a cross-sectional view. FIG. 4 is a perspective view of a paper resin composite-integrated molded container according to the third embodiment of the present invention. 5A is a plan view of the paper resin composite integrally formed container shown in FIG. 4, and FIG. 5B is a cross-sectional view. FIG. 6 is a perspective view of a paper resin composite integral-molded container according to the fourth embodiment of the present invention. FIG. 7A is a plan view of the paper resin composite integrally formed container shown in FIG. 6, and FIG. 7B is a cross-sectional view. FIG. 8 is a perspective view of the paper resin composite integrally molded container according to the fifth embodiment of the present invention turned upside down and viewed from the bottom. FIG. 9 shows an example of the composite sheet before molding. FIG. 10 shows a schematic diagram of a press working apparatus. FIG. 11 is a cross-sectional process diagram illustrating a method for producing a paper resin composite integrally molded container according to the present invention.

Explanation of symbols

  1, 1A, 11, 51, 61 ... Paper resin composite integrally molded container, 3, 3A, 12, 13, 14, 15, 53, 63 ... Recess, 4, 4A, 16, 17, 18, 19, 16a, 17a , 18a, 19a, 54, 64 ... bottom surface, 5, 5A, 20, 21, 22, 23, 20a, 21a, 22a, 23a, 55, 65 ... wall surface, 6, 7, 6A, 7A, 24, 25, 26 , 27, 28, 29, 30, 31, 33, 34, 35, 36, 56, 57, 66, 67, 70, 71 ... weakened part, 8, 8A, 18, 58 ... partition wall, 2, 1a, 11a , 11b, 51a...

Claims (9)

  A paper resin composite sheet comprising a resin layer on at least one surface of a paper layer, and a weakened portion that weakens the strength of the paper layer and allows stretching deformation of the resin layer.   A base part comprising the paper resin composite sheet according to claim 1 and a concave part comprising the paper resin composite sheet press-molded continuously and continuously from the base part, wherein at least one of the base part or the concave part. A paper resin composite-integrated container characterized in that the weakened part is formed in the part.   The rupture portion is formed in a part of the paper layer starting from the formation position of the weakened portion, and the recess is formed by extending the resin layer through the rupture portion. 3. The paper resin composite integrally molded container according to 2.   The paper resin composite integrally formed container according to claim 2 or 3, wherein a plurality of the recesses are formed, and a partition wall is provided between the recesses.   5. The paper resin composite according to claim 2, wherein the weakening portion is formed at a boundary portion between a bottom surface and a wall surface of the concave portion and / or a boundary portion between the base portion and the wall surface. Integrally molded container.   The shape of the cross section of the said weakened part is a substantially circular shape, The said weakened part is formed in the said wall surface radially from the center of the said recessed part, The any one of Claims 2-5 characterized by the above-mentioned. Paper resin composite integrally molded container.   The paper resin composite integrated body according to any one of claims 2 to 5, wherein a shape of a cross section of the weakened portion is square, and the weakened portion is formed at a corner of the wall surface. Molded container. Forming a weakened portion that weakens the strength in the paper layer;
Forming a resin layer on at least one surface of the paper layer on which the weakened portion is formed to form a paper resin composite sheet;
A step of integrally pressing the paper layer and the resin layer to form a recess,
In the step of integrally forming the concave portion by press molding, a fracture portion of the paper layer starting from the weakened portion is formed at any of a boundary portion between the bottom surface and the wall surface of the concave portion, the bottom surface, and the wall surface. Then, the paper resin composite sheet is stretched to form the concave portion, and the method for producing a paper resin composite integral-molded container. Forming a resin layer on at least one surface of the paper layer to form a paper resin composite sheet;
Forming a weakened portion that weakens the strength of the paper layer on which the resin layer is formed;
A step of integrally pressing the paper layer and the resin layer to form a recess,
In the step of integrally forming the concave portion by press molding, a fracture portion of the paper layer starting from the weakened portion is formed at any of a boundary portion between the bottom surface and the wall surface of the concave portion, the bottom surface, and the wall surface. Then, the paper resin composite sheet is stretched to form the concave portion, and the method for producing a paper resin composite integral-molded container.

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