JP2024003435A - Plastic container and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic container with a structure allowing the opposite side face of a metal mold abutting face to serve as a face with preferable peelability and also allowing a fine shape to be formed on a face opposite to the metal mold abutting face.

SOLUTION: A plastic container 100 is manufactured by air-pressure forming or vacuum forming using a non-foaming sheet 80. An uneven shape 20 is formed on a face opposite to the metal mold abutting face being the face brought into contact with the mold in molding. The uneven shape 20 has a corner part with a radius of curvature smaller than thickness of the plastic container 100.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a plastic container and a method for manufacturing a plastic container.

A plastic container manufactured by air pressure forming or vacuum forming is described, for example, in Patent Document 1.

Japanese Patent Application Publication No. 2011-178400

However, according to the inventor's study, in general vacuum-formed products and pressure-formed products as described in Patent Document 1, there is a limit to the sharpness of the uneven shape on the surface opposite to the mold contact surface. (As described later, the limit is the radius of curvature of the corner = the thickness of the plastic container). For this reason, for example, it is difficult to make the surface opposite to the mold contact surface a surface with good peelability, or it is difficult to form a fine shape on the surface opposite to the mold contact surface. The problem is that it is difficult to do so.

The present invention has been made in view of the above-mentioned problems, and includes making the surface opposite to the mold contact surface a surface having good releasability, and making the surface opposite to the mold contact surface a fine surface. The present invention provides a plastic container having a structure that can be shaped, and a method for manufacturing the plastic container.

According to the present invention, a plastic container manufactured by pressure forming or vacuum forming using a non-foamed sheet,
An uneven shape is formed on the surface opposite to the mold contact surface, which is the surface that comes into contact with the mold during molding.
The uneven shape provides a plastic container having corners with a radius of curvature smaller than the wall thickness of the plastic container.

Further, according to the present invention, there is provided a method for manufacturing a plastic container by pressure forming or vacuum forming, comprising:
a step of adsorbing a non-foamed sheet to a mold and molding the non-foamed sheet into a shape that follows the mold;
Pressing a mold for forming an uneven shape on the surface of the non-foamed sheet opposite to the mold contact surface that contacts the mold to transfer the uneven shape to the opposite surface;
Equipped with
In the step of transferring, there is provided a method for manufacturing a plastic container in which an uneven shape having corners having a radius of curvature smaller than the wall thickness of the plastic container is formed on the opposite surface.

According to the present invention, the uneven shape formed on the surface opposite to the mold contact surface has a corner portion with a radius of curvature smaller than the wall thickness of the plastic container. This provides a plastic container having a structure in which the surface opposite to the mold contact surface has good releasability, and a plastic container having a structure in which a fine shape is formed on the surface opposite to the mold contact surface. be able to.

FIG. 1(a) is a plan view of the plastic container according to the first embodiment, and FIG. 1(b) is a partially enlarged view of FIG. 1(a). 2(a) is a sectional view taken along the line AA in FIG. 1(a), and FIG. 2(b) is a partially enlarged view of section A shown in FIG. 2(a). FIG. 1B is a sectional view taken along line BB in FIG. 1(b). FIGS. 4(a), 4(b), and 4(c) are schematic diagrams for explaining the method for manufacturing a plastic container according to the first embodiment. 5(a) and 5(b) are cross-sectional views of the non-foamed sheet in the first embodiment, of which FIG. 5(a) shows the state before the step of transferring the uneven shape, and FIG. 5(b) shows the state after the step of transferring the uneven shape is performed. FIGS. 6A and 6B are profile data showing the results of actually measuring the uneven shape of the plastic container according to the first embodiment. FIG. 3 is a diagram showing a photograph of a cross section of an uneven shape obtained by the method for manufacturing a plastic container according to the first embodiment. 8(a) and 8(b) are cross-sectional views of the non-foamed sheet in Modification 1 of the first embodiment, of which FIG. 8(a) shows the state before the step of transferring the uneven shape is performed. FIG. 8(b) shows the state after the process of transferring the uneven shape is performed. FIG. 9(a) is a plan view of a plastic container according to modification 2 of the first embodiment, and FIG. 9(b) is a partially enlarged view of FIG. 9(a). 10(a) is a cross-sectional view taken along line AA in FIG. 9(a), and FIG. 10(b) is a cross-sectional view taken along line BB in FIG. 9(b). FIG. 11(a) is a plan view of a plastic container according to the second embodiment, and FIG. 11(b) is a partially enlarged view of FIG. 11(a). 12(a) is a cross-sectional view taken along line AA in FIG. 11(a), and FIG. 12(b) is a cross-sectional view taken along line BB shown in FIG. 11(b). FIG. 13(a) is a partially enlarged view of the uneven shape and its surrounding structure in a modified example of the second embodiment, and FIG. 13(b) is a sectional view taken along line AA shown in FIG. 13(a). 13(c) is a sectional view taken along line BB shown in FIG. 13(a). It is a top view of the plastic container based on 3rd Embodiment. FIG. 15(a) is a partially enlarged view of the uneven shape and its peripheral structure according to the third embodiment, and FIG. 15(b) is a sectional view taken along line AA shown in FIG. 15(a). FIG. 16(a) is a plan view of a plastic container according to the fourth embodiment, and FIG. 16(b) is a partially enlarged view of FIG. 16(a). 17(a) is a cross-sectional view taken along line AA in FIG. 16(a), and FIG. 17(b) is a cross-sectional view taken along line BB shown in FIG. 16(b). FIGS. 18(a) and 18(b) are diagrams for explaining the limit of the radius of curvature of the corner of the uneven shape on the opposite side to the die contacting surface of the air pressure molded product.

Embodiments of the present invention will be described below with reference to FIGS. 1(a) to 18(b). In addition, in all the drawings, the same reference numerals are given to the same components, and the explanation is omitted as appropriate.

[First embodiment]
First, a first embodiment will be described using FIGS. 1(a) to 7.

As shown in FIGS. 4(a) to 4(c), the plastic container 100 according to the present embodiment is a plastic container manufactured by air pressure forming or vacuum forming using a non-foamed sheet 80.
In the plastic container 100, the surface opposite to the mold contacting surface (in this embodiment, one surface 80a of the non-foamed sheet 80) that is the surface in contact with the mold during molding (in the case of this embodiment, a non-foamed surface) An uneven shape 20 is formed on the other surface 80b of the sheet 80 (see FIGS. 1(a) to 3). As shown in FIG. 3, the uneven shape 20 has a corner portion (in the case of this embodiment, a top portion 35 to be described later) whose radius of curvature is smaller than the wall thickness of the plastic container 100.

According to this embodiment, the uneven shape 20 formed on the surface opposite to the mold contact surface has a corner portion (in the case of this embodiment, the top portion 35) whose radius of curvature is smaller than the wall thickness of the plastic container 100. have Therefore, it is possible to provide a plastic container having a structure in which the surface opposite to the mold contact surface has good releasability, and a plastic container having a structure in which a fine shape is formed on the opposite surface. Furthermore, such an uneven shape 20 can be formed without depending on the shape of the mold contacting surface.

The plastic container 100 will be described in more detail below.
In addition, below, when explaining the positional relationship etc. of each component of the plastic container 100, the upper side in Fig.2 (a) is called an upper side, upper part, etc., and the opposite side is called a lower side, a lower part, etc. However, these directions are for convenience and do not limit the directions when the plastic container 100 is manufactured or used.

The entire plastic container 100 is integrally formed by air pressure forming or vacuum forming using a non-foamed sheet 80. Although pressure forming or vacuum forming is not particularly limited, examples thereof include pressure release molding, pressure vacuum forming, vacuum pressure forming, and the like.
In the case of this embodiment, as shown in FIGS. 4(a) to 4(c), one surface 80a of the non-foamed sheet 80 constitutes the mold contacting surface and thus the outer surface 100a of the plastic container 100, The other surface 80b of the non-foamed sheet 80 constitutes the surface opposite to the mold contacting surface, and thus the inner surface 100b of the plastic container 100 (see FIGS. 4(a) to 4(b)).
As shown in FIGS. 1(a) and 2(a), in the case of this embodiment, the plastic container 100 has a general shape of a flat box (with a shallow vertical depth dimension). The planar shape of the plastic container 100 is approximately rectangular (rectangular shape with rounded corners). More specifically, the planar shape of the plastic container 100 is approximately rectangular.

As shown in FIGS. 1(a) and 2(a), in the case of the present embodiment, the plastic container 100 includes a main body 10 that accommodates the contents, and a top opening 13 of the main body 10 that protrudes to the periphery. It has a flange portion 12.
In the case of this embodiment, the outer surface 100a of the plastic container 100 includes the outer surface of the main body 10 and the lower surface of the flange 12, and the inner surface 100b of the plastic container 100 includes the inner surface of the main body 10 and the upper surface of the flange 12. including.

The main body part 10 includes a body part 11 having an open upper end and a bottom part 14 closing the lower end of the body part 11.
The planar shape of the body portion 11 is approximately rectangular (rectangular shape with rounded corners).
As shown in FIG. 2(a), in the body part 11, the lower part of the upper end part 16 (hereinafter referred to as the body body part 11a) is inclined in two steps so that the planar dimension slightly increases upward. are doing. A stepped portion 17 is formed between the upper edge of the body portion 11 a of the body portion 11 and the lower edge of the upper end portion 16 . The stepped portion 17 is a rectangular annular portion that projects radially outward from the upper edge of the fuselage main body portion 11a in a flange shape, and the outer peripheral edge of the stepped portion 17 is connected to the lower edge of the upper end portion 16. ing. In other words, the stepped portion 17 protrudes radially inward from the lower edge of the upper end portion 16 in the shape of an inner flange.

Note that, of the side circumferential wall of the body portion 11, the center portion of the portion corresponding to the long side of the substantially rectangular body portion 11 is offset toward the inside of the plastic container 100 from both ends of the portion corresponding to the long side. For this reason, step portions are formed between the center portion and both end portions of the long sides of the substantially rectangular body portion 11, respectively.

Although the shape of the bottom part 14 is not particularly limited, in the case of this embodiment, as shown in FIG. It is higher than the original position. Between the center portion 14a of the bottom portion 14 and the peripheral portion 14b of the bottom portion 14, a plurality of stepped portions 14c (see FIG. 2(b)) are disposed downward in a stepwise manner toward the outside in the radial direction. is formed.
The planar shape of the central portion 14a is, for example, approximately rectangular, and its longitudinal direction is parallel to the long sides of the approximately rectangular plastic container 100. However, in the present invention, the planar shape of the central portion 14a may be an ellipse or an ellipse.
The planar shape of the stepped portion 14c is formed into a rectangular ring shape along the outline of the central portion 14a.

As shown in FIG. 2(a), the flange portion 12 is, for example, arranged flat and substantially horizontally. However, the outer peripheral edge of the flange portion 12 is displaced downward in a stepwise manner toward the outside in the radial direction.

In the case of this embodiment, the plastic container 100 is formed into the above-mentioned general shape.
However, in the present invention, the general shape of the plastic container 100 is not limited to the above example, and may be, for example, a bottomed cylindrical shape (cup shape).

The contents of the plastic container 100 are not particularly limited, but can be, for example, food. Note that the contents of the plastic container 100 are not particularly limited, and may be liquid (including fluid) or solid.
For example, after being filled with contents, the plastic container 100 is distributed with a film-like lid (not shown) provided on the flange 12. The lid portion is joined to the upper surface of the flange portion 12 by heat sealing, for example.

In the case of this embodiment, an uneven shape 20 is formed on the inner surface 100b of the plastic container 100. As described above, the uneven shape 20 has a corner portion (in the case of this embodiment, the top portion 35) whose radius of curvature is smaller than the wall thickness of the plastic container 100.
This makes it possible to realize a structure with good releasability and a fine structure on the inner surface 100b, regardless of the shape of the outer surface 100a, which is the mold contacting surface.

More specifically, as shown in FIGS. 1A and 2A, for example, an uneven shape 20 is formed on the inner surface of the bottom surface of the plastic container 100 (the inner surface of the bottom surface portion 14).
Thereby, a structure having good releasability or a fine structure can be formed on the inner surface 100b of the bottom surface.

On the other hand, the mold contact surface (in the case of this embodiment, the outer surface 100a) does not have, for example, the uneven shape 20 (the uneven shape as shown in FIG. 3).
Thereby, for example, the outer surface 100a of the plastic container 100 can be made into a flatter shape, so that a label or the like can be properly attached to the outer surface 100a.
Here, "the mold contact surface does not have the uneven shape 20" means that the mold contact surface has substantially the same shape as the uneven shape 20 at least in the region corresponding to the region where the uneven shape 20 is formed. This means that the region does not have an uneven shape, and preferably the region is flat.

As shown in FIGS. 1A to 3, in the case of this embodiment, the uneven shape 20 includes a plurality of microprotrusions 30. The radius of curvature of the top portion 35 of the microprotrusion 30 is smaller than the wall thickness of the plastic container 100.
According to such a configuration, the contact area between the contents of the plastic container 100 and the inner surface 100b of the plastic container 100 can be reduced. Therefore, for example, even if the content is highly sticky such as rice cake, the content can be more easily peeled off from the inner surface 100b of the plastic container 100. Further, for example, a plurality of microprotrusions 30 can also be used as a slip prevention member.
Furthermore, since the tops 35 of the microprotrusions 30 can be formed more sharply, the region where the plurality of microprotrusions 30 are formed on the inner surface 100b can be used as a grater, for example.

Here, in the present invention, the wall thickness of the plastic container 100 is the maximum wall thickness T (see FIG. 3) in the region where the uneven shape 20 is formed. The radius of curvature of the corner of the uneven shape 20 is preferably smaller than the average thickness of the region in which the uneven shape 20 is formed. Note that the region in which the uneven shapes 20 are formed means the minimum area that includes all the uneven shapes 20.
Further, in the present invention, "the radius of curvature of the corner of the uneven shape 20" is measured using an arc-shaped template 29 (see FIG. 3) having a center angle of 90 degrees. More specifically, when the templates 29 are fitted from above the microprotrusion 30 in descending order of the radius of curvature, the template 29 that fits the top 35 of the microprotrusion 30 has the largest radius of curvature. Let the radius of curvature of the small template 29 be the radius of curvature of the corner of the uneven shape 20. It should be noted that fit here means that at least both ends of the template 29 are in contact with the contour lines of the corners of the uneven shape 20.
The radius of curvature of the corner of the uneven shape 20 can be measured using, for example, profile data of the uneven shape 20 (see FIGS. 6(a) and 6(b)) or a photograph of a cross section of the uneven shape 20 (see FIG. 7). ), etc., by fitting the template 29 onto the corner of the screen of a PC (Personal Computer).

As shown in FIG. 1(a), the plurality of microprotrusions 30 are formed substantially uniformly over substantially the entire inner surface of the central portion 14a of the bottom portion 14. As shown in FIG. On the other hand, the plurality of microprotrusions 30 are not formed on the outer surface of the central portion 14a of the bottom surface portion 14, and the outer surface is substantially flat.
Each of the plurality of microprotrusions 30 is formed, for example, in the shape of a quadrangular pyramid (pyramid shape) convex upward. The top of the microprotrusion 30 is constituted by the top of this quadrangular pyramid shape. The top portion 35 of the microprotrusion 30 has a rounded shape.
As shown in FIG. 1(b), each of the plurality of microprotrusions 30 is arranged in a square lattice shape when viewed from above. More specifically, each of the plurality of microprotrusions 30 is arranged alongside each other in both the longitudinal direction and the lateral direction of the plastic container 100. Of the four sides of the bottom of each microprotrusion 30, two sides are arranged along the longitudinal direction of the plastic container 100, and the remaining two sides are arranged along the transverse direction of the plastic container 100. . In the case of this embodiment, a slight gap is formed between adjacent microprotrusions 30, but in the present invention, even if the gap is not formed and each microprotrusion 30 is formed continuously. good.
Further, as shown in FIG. 3, a plurality of valleys 37 are formed by a plurality of adjacent microprotrusions 30. The radius of curvature of the valley portion 37 is smaller than the radius of curvature of the top portion 35 of the microprotrusion 30, for example. In addition, in FIG. 1(b), the valley portion 37 with a smaller radius of curvature is illustrated with a solid line for convenience, and the representation using a solid line is omitted for the top portion 35 with a larger radius of curvature. There is.
As shown in FIG. 3, along the two opposing sides of the microprotrusion 30 and along the line passing through the apex of the microprotrusion 30 (for example, line BB shown in FIG. 1(b)). In the cut cross section, the shape of the aggregate of the plurality of microprotrusions 30 is, for example, a triangular wave shape. More specifically, in this cross section, the inner surface of the central portion 14a has a triangular wave shape, while the outer surface of the central portion 14a has a substantially linear shape extending in the horizontal direction.
However, in the present invention, the shape of the aggregate of the plurality of microprotrusions 30 in a cross section taken in a direction along two opposing sides of the microprotrusions 30 and along a line passing through the apex of the microprotrusions 30 is However, the shape is not limited to this example, and may have a substantially rectangular wave shape, an arc shape, or the like.

In the case of this embodiment, the maximum wall thickness T of the plastic container 100 is not particularly limited, but is preferably, for example, 0.1 mm or more and 2.0 mm or less, and more preferably 0.5 mm or more and 1 mm or less. In the case of this embodiment, as an example, the maximum wall thickness T of the plastic container 100 is 0.6 mm or more and 0.8 mm or less.

In the case of this embodiment, the radius of curvature of the top portion 35 of the plurality of microprotrusions 30 is smaller than the wall thickness (maximum wall thickness T) of the plastic container 100. Note that the radius of curvature here is the average value of the radius of curvature in a direction along two opposing sides of the microprotrusion 30 and in a cross section cut along a line passing through the apex of the microprotrusion 30.
More specifically, the radius of curvature of the top 35 of the microprotrusion 30 is preferably 0.01 mm or more and 0.5 mm or less, more preferably 0.05 mm or more and 0.4 mm or less. As an example, in the case of this embodiment, the radius of curvature of the top portion 35 of the microprotrusion 30 is 0.2 mm or more and 0.3 mm or less.
The protrusion height H1 (FIG. 3) of the microprotrusions 30 is preferably 0.1 mm or more and 0.7 mm or less, more preferably 0.2 mm or more and 0.6 mm or less. As an example, the protrusion height H1 of the microprotrusion 30 is 0.4 mm or more and 0.6 mm or less.
The equivalent circle diameter R1 (FIG. 3) of the microprotrusion 30 is preferably 0.1 mm or more and 4.0 mm or less, more preferably 0.5 mm or more and 2.0 mm or less. In the case of this embodiment, as an example, the equivalent circle diameter R1 of the microprotrusion 30 is 1.0 mm or more and 1.3 mm or less.
Here, the dimensions of the plurality of microprotrusions 30 may be equal to each other or may be different from each other.
Further, the distance L1 (FIG. 3) between the vertices of adjacent microprotrusions 30 is preferably 0.2 mm or more and 8.0 mm or less, more preferably 0.2 mm or more and 4.0 mm or less. . In the case of this embodiment, as an example, the distance L1 between the vertices of the microprotrusions 30 is 1.0 mm or more and 1.2 mm or less.
Further, the width dimension W1 (FIG. 3) of the gap between adjacent microprotrusions 30 is preferably 0.01 mm or more and 1.0 mm or less, more preferably 0.05 mm or more and 0.5 mm or less. preferable. In the case of this embodiment, as an example, the width dimension W1 of the gap between adjacent microprotrusions 30 is 0.09 mm or more and 0.11 mm or less.
In the present invention, in a direction along the diagonal line of the microprotrusion 30 and in a cross section (not shown) along a line passing through the apex of the microprotrusion 30 (for example, line CC shown in FIG. 1(b)), Also, the radius of curvature of the top portion 35 of the plurality of microprotrusions 30 is preferably smaller than the wall thickness (maximum wall thickness T) of the plastic container 100.

An example of a method for manufacturing the plastic container 100 (hereinafter sometimes referred to as the present method) will be described below with reference to FIGS. 4(a) to 4(b). In addition, below, the plastic container 100 will be manufactured by pressure molding as an example.
This method includes the steps of adsorbing the non-foamed sheet 80 to a mold 200 and molding the non-foamed sheet 80 into a shape that follows the mold 200; The method includes a step of pressing the uneven shape forming mold 300 on the surface (the other surface 80b) opposite to the contact surface (one surface 80a) to transfer the uneven shape 20 to the opposite surface.
Note that in FIGS. 4(a) to 4(c), the non-foamed sheet 80 (plastic container 100) is shown in an upside-down position. Furthermore, in FIGS. 4A to 4C, the non-foamed sheet 80, the mold 200, and the uneven shape forming mold 300 are shown in cross section along the longitudinal direction of the non-foamed sheet 80. Moreover, in FIGS. 4(b) and 4(c), the mold 300 for forming an uneven shape is schematically shown, and the unevenness of the mold 300 for forming an uneven shape is shown in a size larger than the actual size ratio. Illustrated in proportions.

More specifically, first, the non-foamed sheet 80 is heated with a heater (not shown) to plasticize it. Then, as shown in FIG. 4(a), the plasticized non-foamed sheet 80 is arranged so that one surface 80a is located on the mold 200 side and the other surface 80b is located on the opposite side from the mold 200 side. do. In this embodiment, the mold 200 is a female mold. Further, the mold 200 has vacuum holes (not shown) formed therein.
Then, the non-foamed sheet 80 is pressurized to the mold 200 side with compressed air while being vacuum-suctioned through the vacuum hole. Thereby, the non-foamed sheet 80 can be adsorbed to the mold 200, and the non-foamed sheet 80 can be molded into a shape that conforms to the mold 200. More specifically, the mold contacting surface (one surface 80a) of the non-foamed sheet 80 is curved along the unevenness of the mold 200, and the opposite surface (the other surface 80b) is also the mold contacting surface. The non-foamed sheet 80 is curved into substantially the same shape, and the thickness of the non-foamed sheet 80 is offset toward the opposite surface.
As a result, the non-foamed sheet 80 is formed into a box shape as shown in FIGS. 1(a) and 2(a). One surface 80a of the non-foamed sheet 80 becomes the outer surface 100a of the plastic container 100, and the other surface 80b becomes the inner surface 100b of the plastic container 100.

Next, as shown in FIG. 4(b), before the non-foamed sheet 80 is solidified (in a plasticized state), the non-foamed sheet 80 is placed against the mold contacting surface, which is the surface that contacts the mold 200. The uneven shape forming mold 300 is pressed on the opposite surface (the other surface 80b). As a result, the resin of the non-foamed sheet 80 enters between the unevenness of the uneven shape forming mold 300, and the uneven shape 20 is transferred to the opposite surface (the other surface 80b), that is, the inner surface 100b of the plastic container 100. I can do it. The transferred uneven shape 20 has corners with a radius of curvature smaller than the wall thickness of the plastic container 100. After the uneven shape 20 is transferred to the opposite surface (inner surface 100b), the uneven shape forming mold 300 is separated from the opposite surface, and the non-foamed sheet 80 is cooled. After the non-foamed sheet 80 is sufficiently cooled and solidified, the non-foamed sheet 80 is released from the mold 200.
In this way, a plastic container 100 is obtained.

In addition, in a plastic container manufactured by pressure forming or vacuum forming, in the forming area of the curved shape 90 (for example, see FIG. 2(b)) to which the shape of the mold 200 is transferred, the corners of the mold contact surface are The half-curvature is smaller than the half-curvature of the corner of the opposite surface. In addition, in FIG. 2(b) and the like, there is no distinction between the curvature half-shape of the corner part of the mold contact surface and the curvature half-shape of the corner part of the opposite surface, and each is shown schematically. There is.
In addition, since vacuum suction is performed through the vacuum holes with the mold contacting surface (one surface 80a) of the non-foamed sheet 80 placed on the mold 200 side as described above, the mold contacting surface is vacuumed. A hole scar is formed.
Therefore, it is possible to distinguish between the mold-contacting surface of the plastic container 100 and the opposite surface based on the size relationship of the radius of curvature of the corners of each surface in the forming area of the curved shape 90 and the presence or absence of vacuum hole marks. It can be carried out.

In this way, this method includes the steps of adsorbing the non-foamed sheet 80 to the mold 200 and molding the non-foamed sheet 80 into a shape that follows the mold 200, and The method includes a step of pressing the uneven shape forming mold 300 on the surface opposite to the die contact surface and transferring the uneven shape 20 to the opposite surface.
Then, in the transfer step, an uneven shape 20 having corners having a radius of curvature smaller than the wall thickness of the plastic container 100 is formed on the opposite surface.

Here, as shown in FIGS. 5(a) and 5(b), in the case of this embodiment, the non-foamed sheet 80 has a laminated structure having multiple layers.
More specifically, the non-foamed sheet 80 has, for example, a laminate structure of three or more layers including a barrier layer 81 as an intermediate layer.
As shown in FIGS. 5(a) and 5(b), in the case of the present embodiment, the non-foamed sheet 80 includes, in addition to the barrier layer 81, a surface layer 86, a first base layer 82, and a first base layer 82. The second base material layer 83 and the third base material layer 87 are provided. Furthermore, the non-foamed sheet 80 has a first adhesive layer 84 that adheres one side of the barrier layer 81 to the first base layer 82 and a second base layer 83 that adheres the other side of the barrier layer 81 to the first base layer 82 . A second adhesive layer 85 that adheres to the second adhesive layer 85 is provided.
In the non-foamed sheet 80, the surface layer 86, the first base layer 82, the first adhesive layer 84, the barrier layer 81, the second adhesive layer 85, the second base layer 83, and the third base layer 87. They are stacked in order from the top. The surface of the surface layer 86 opposite to the first base layer 82 side constitutes the other surface 80b of the non-foamed sheet 80 (the surface opposite to the mold contact surface). The surface of the base material layer 87 of No. 3 on the side opposite to the second base material layer 83 side constitutes one surface 80a (mold contact surface) of the non-foamed sheet 80.
In the case of this embodiment, the thickness dimension of the first base material layer 82 and the thickness dimension of the second base material layer 83 are set to be approximately equal to each other, and the barrier layer 81 is similar to the non-foamed sheet 80. It is arranged in the middle part in the thickness direction.

Here, in the case of the present embodiment, among the multiple layers of the non-foamed sheet 80, the melt flow rate (MFR) of the layer constituting the surface on the opposite side to the mold contact surface (in the case of the present embodiment, the surface layer 86) is larger than the melt flow rate of other layers.
According to such a configuration, when pressing the uneven shape forming mold 300 on the opposite surface (the other surface 80b) of the non-foamed sheet 80 while maintaining the ease of molding the non-foamed sheet 80, , it becomes possible to transfer sharper and finer uneven shapes 20.
More specifically, for example, among the multiple layers of the non-foamed sheet 80, the melt flow rate (MFR) of the layer (surface layer 86) constituting the opposite surface is higher than that of the other layer (for example, the first base material). It is preferably 1.1 times or more and 10 times or less, more preferably 2 times or more and 4 times or less, the melt flow rate of the layer 82, the second base layer 83, and the third base layer 87).
However, in the present invention, the melt flow rate (MFR) of the layer constituting the surface opposite to the mold contact surface may be equal to the melt flow rate of other layers.

In the case of this embodiment, the surface layer 86 is made of a resin composition containing polypropylene resin as a main component, although it is not particularly limited. The melt flow rate (MFR) of this polypropylene resin is, for example, 4 g/10 minutes or more and 10 g/10 minutes or less.
Each of the first base layer 82, the second base layer 83, and the third base layer 87 is made of, for example, a resin whose main component is a mixture of a polypropylene resin and a polyethylene resin, although it is not particularly limited. It is made up of a composition. The melt flow rate (MFR) of this polypropylene resin and polyethylene resin is, for example, 0.3 g/10 minutes or more and 4.0 g/10 minutes or less.
Barrier layer 81 is an oxygen barrier layer containing, for example, ethylene vinyl alcohol resin such as ethylene-vinyl alcohol copolymer (EVOH), although it is not particularly limited.
Although not particularly limited, each of the first adhesive layer 84 and the second adhesive layer 85 is made of, for example, maleic anhydride-modified polypropylene.

Here, profile data of the uneven shape 20 (microprotrusions 30) of the plastic container 100 obtained by this method is shown in FIGS. 6(a) and 6(b). In these profile data, the shape of the surface of the microprotrusion 30 (the surface opposite to the mold contact surface) was measured at intervals of 0.007 mm using a three-dimensional measuring instrument. In FIGS. 6(a) and 6(b), the horizontal axis indicates the distance from the measurement start point, and the vertical axis indicates the change in the protrusion height of the microprotrusion 30 corresponding to the distance. Moreover, the wall thickness of the plastic container 100 shown in FIGS. 6(a) and 6(b) is 0.7 mm.
The average value of the radius of curvature of the top portion 35 of each microprotrusion 30 shown in FIG. 6(a) is 0.23 mm or more and 0.25 mm or less. Further, the average value of the protrusion height of each microprotrusion 30 is 0.5 mm or more and 0.52 mm or less, and the average value of the distance between the vertices of adjacent microprotrusions 30 is 1.07 mm or more and 1.09 mm or less. It is.
The average value of the radius of curvature of the top portion 35 of each microprotrusion 30 shown in FIG. 6(b) is 0.2 mm or more and 0.22 mm or less. Further, the average value of the protruding height of each microprotrusion 30 is 0.4 mm or more and 0.49 mm or less, and the average value of the distance between the vertices of adjacent micro protrusions 30 is 0.8 mm or more and 0.89 mm or less. It is.
Note that the average value here refers to the average value of each dimension of the microprotrusions 30 in the range measured using a three-dimensional measuring instrument among the plurality of microprotrusions 30.

Further, FIG. 7 shows a photograph of a cross section of the uneven shape 20 of the plastic container 100 obtained by this method. In addition, in order to explain the limit of the radius of curvature of the corner of the uneven shape on the surface opposite to the mold contact surface in a general method for manufacturing plastic containers by air pressure forming or vacuum forming, the uneven shape 420 was manufactured. Photographs of the cross section are shown in FIGS. 18(a) and 18(b). In the plastic container 400 shown in FIGS. 18(a) and 18(b), when molding the plastic container 400 by pressure forming or vacuum forming, the tip of the Thomson blade (not shown) is placed on the mold contact surface 400a. By pressing, an uneven shape 420 (protrusion 430) was formed on the surface 400b opposite to the mold contact surface 400a. More specifically, the mold contact surface 400a is curved along the tip of the Thomson blade, and the opposite surface 400b is also curved in substantially the same shape as the mold contact surface 400a, and the wall thickness of the plastic container 400 is shaped into a shape offset toward the opposite surface 400b. As a result, a protrusion 430 that is convex toward the opposite surface 400b is formed on the opposite surface 400b, while a portion of the mold contacting surface 400a corresponding to the protrusion 430 is formed on the opposite surface 400b. A recess 436 is formed that is recessed toward the surface 400b. The trough 437 of the recess 436 has a shape that is the shape of the tip of the Thomson blade.
Further, the wall thickness of the plastic container 100 shown in FIG. 7 and the wall thickness of the plastic container 400 shown in FIGS. be.
The radius of curvature of the top portion 35 of the microprotrusion 30 of the plastic container 100 shown in FIG. 7 is 0.24 mm. The protrusion height of the microprotrusions 30 is 0.4 mm. Further, the length of one side of the bottom of the microprotrusion 30 is 1.0 mm, and therefore the equivalent circle diameter of the microprotrusion 30 is 1.13 mm.
Further, the mold contact surface (outer surface 100a) of the plastic container 100 is substantially flat.
On the other hand, the radius of curvature of the top portion 435 of the uneven shape 420 (protrusion 430) shown in FIGS. 18(a) and 18(b) is 0.7 mm. More specifically, in the general manufacturing method of plastic containers by pressure forming or vacuum forming, when forming an uneven shape on the surface opposite to the mold contact surface, the mold contact surface is formed along the mold unevenness. Shape. As a result, the surface opposite to the mold contact surface is curved into a shape that reflects the unevenness of the mold contact surface, and the thickness of the plastic container is offset to the opposite surface, resulting in an uneven shape. is formed. For this reason, in this manufacturing method, even if a sharp tool such as a Thomson blade is pressed against the mold contact surface instead of the unevenness of the mold, the uneven corners formed on the opposite surface The limit for the radius of curvature of the part is a size equivalent to the wall thickness of the plastic container.

As described above, according to this method, since the uneven shape 20 has a corner portion (in the case of this embodiment, the top portion 35) whose radius of curvature is smaller than the wall thickness of the plastic container 100, It is possible to provide a plastic container having a structure in which the surface has good releasability, and a plastic container having a structure in which a fine shape is formed on the surface opposite to the mold contact surface. Moreover, such an uneven shape 20 can be formed without depending on the shape of the mold contact surface.

<Modification 1 of the first embodiment>
Next, a first modification of the first embodiment will be described using FIGS. 8(a) and 8(b).
The plastic container 100 according to the present modification is different from the plastic container 100 according to the first embodiment described above in the following points, and the plastic container 100 according to the first embodiment described above is different from the plastic container 100 according to the first embodiment described above in other points. It is configured in the same way.

In the case of this modification, the barrier layer 81 is formed on the mold contact surface (one surface 80a ) side.
By doing this, when transferring the uneven shape 20, deformation of the barrier layer 81 due to deformation of the non-foamed sheet 80 (such as the barrier layer 81 being locally thinned in areas crushed by pressure) can be avoided. ), the barrier layer 81 has a more uniform thickness overall.

<Modification 2 of the first embodiment>
Next, a second modification of the first embodiment will be described using FIGS. 9(a) to 10(b). In addition, in FIGS. 9(a) and 10(a), in order to avoid complicating the drawings, the number of the plurality of microprotrusions 30 is reduced and the dimensions are shown at a larger ratio than the actual size ratio.
The plastic container 100 according to the present modification is different from the plastic container 100 according to the first embodiment described above in the following points, and the plastic container 100 according to the first embodiment described above is different from the plastic container 100 according to the first embodiment described above in other points. It is configured in the same way.

As shown in FIGS. 9A to 10B, in the case of this modification, each of the plurality of microprotrusions 30 is formed, for example, in a substantially conical shape that protrudes upward. The top portion 35 of the microprotrusion 30 is constituted by this conical top portion. The top portion 35 of the microprotrusion 30 has a rounded shape.
As shown in FIGS. 9A and 9B, the plurality of microprotrusions 30 are arranged adjacent to each other in plan view.
As shown in FIG. 10(b), in a cross section cut along a line connecting the vertices of a plurality of adjacent microprotrusions 30 (for example, line BB shown in FIG. 9(b)), a plurality of microprotrusions 30 The shape of the aggregate is, for example, a wavy line. More specifically, in this cross section, the inner surface of the center portion 14a has a wavy line shape, while the outer surface of the center portion 14a has a substantially linear shape extending in the horizontal direction.

Also in the case of this modification, the radius of curvature of the top portion 35 of the plurality of microprotrusions 30 is smaller than the wall thickness (maximum wall thickness T) of the plastic container 100. Note that the radius of curvature here is the average value of the radius of curvature in a cross section cut along a line connecting the vertices of a plurality of adjacent microprotrusions 30.
In the case of this modification, the radius of curvature of the top portion 35 of the plurality of microprotrusions 30 is preferably 0.01 mm or more and 0.5 mm or less, more preferably 0.05 mm or more and 0.4 mm or less. As an example, in the case of this embodiment, the radius of curvature of the top portion 35 of the plurality of microprotrusions 30 is 0.2 mm or more and 0.4 mm or less.
The protrusion height H2 (FIG. 10(b)) of the microprotrusions 30 is preferably 0.1 mm or more and 0.7 mm or less, more preferably 0.2 mm or more and 0.6 mm or less. As an example, the protrusion height H2 of the microprotrusion 30 is 0.3 mm or more and 0.5 mm or less.
The diameter R2 (FIG. 10(b)) of the microprotrusion 30 is preferably 0.1 mm or more and 4.0 mm or less, more preferably 0.5 mm or more and 2.0 mm or less.
The distance L2 between the vertices of adjacent microprotrusions 30 (FIG. 10(b)) is preferably 0.2 mm or more and 8.0 mm or less, more preferably 0.2 mm or more and 4.0 mm or less. preferable. In the case of this modification, as an example, the distance L2 between the vertices of the microprotrusions 30 is 0.9 mm or more and 1.0 mm or less.
Here, the dimensions of the plurality of microprotrusions 30 may be equal to each other or may be different from each other.
In the present invention, it is sufficient that the radius of curvature of the top portion 35 at least in a cross section along the direction in which the radius of curvature of the top portion 35 is the minimum is smaller than the wall thickness of the plastic container 100, and preferably the radius of curvature of the top portion 35 is smaller than the wall thickness of the plastic container 100. The radius of curvature of the top portion 35 in the cross section along the maximum direction is also smaller than the wall thickness of the plastic container 100.

[Second embodiment]
Next, a second embodiment will be described using FIGS. 11(a) to 12(b). Note that in FIG. 12(b), illustration of the template 29 is omitted.
The plastic container 100 according to the present embodiment is different from the plastic container 100 according to the first embodiment described above in the following points, and the plastic container 100 according to the first embodiment described above is different from the plastic container 100 according to the first embodiment described above in other points. It is configured in the same way.

In the case of this embodiment, as shown in FIGS. 11(a) to 12(b), the uneven shape 20 includes a rib 40, and the radius of curvature of the top 45 of the rib 40 is larger than the wall thickness of the plastic container 100. small.
Also with such a configuration, the contact area between the contents of the plastic container 100 and the inner surface 100b of the plastic container 100 can be reduced. Therefore, for example, even if the content is highly sticky such as rice cake, the content can be easily peeled off from the inner surface 100b of the plastic container 100.

In the case of this embodiment, the rib 40 is formed on the inner surface of the central portion 14a of the bottom portion 14.
As shown in FIGS. 11(a) and 11(b), the rib 40 extends in a direction perpendicular to the extending direction of the plurality of first ribs 41 and the plurality of first ribs 41, for example. The second ribs 42 are formed in a lattice shape in plan view. The top portion 45 of the rib 40 is configured, for example, by the top portion of each of the plurality of first ribs 41 and the top portion of each of the plurality of second ribs 42 .
The plurality of first ribs 41 and the plurality of second ribs 42 are each formed into an upwardly convex protrusion, for example.
Each of the plurality of first ribs 41 extends, for example, in a direction that slopes upward to the right in FIG. 11(a), and each of the plurality of second ribs 42 extends in a direction that slopes upward to the left in FIG. It extends in an inclined direction.
The plurality of first ribs 41 are arranged at equal intervals (equal angular intervals), for example, in the extending direction of the plurality of second ribs 42 . Similarly, the plurality of second ribs 42 are arranged at equal intervals (equal angular intervals), for example, in the extending direction of the plurality of first ribs 41.

In a cross section perpendicular to the extending direction of the plurality of first ribs 41 (see FIG. 12(b)), each first rib 41 has a substantially triangular shape.
However, in the present invention, the shape of the first rib 41 in a cross section perpendicular to the extending direction of the first rib 41 may be approximately rectangular or hemispherical.
Similarly, each second rib 42 has a substantially triangular shape in a cross section perpendicular to the direction in which the plurality of second ribs 42 extend. Note that the shape of each second rib 42 in a cross section perpendicular to the extending direction of the plurality of second ribs 42 is the same as that of the first rib 41, so illustration thereof is omitted.
However, in the present invention, the shape of the first rib 41 in a cross section perpendicular to the extending direction of the first rib 41, and the shape of the second rib 42 in a cross section perpendicular to the extending direction of the second rib 42. and may have different shapes.

In the case of this embodiment, the radius of curvature of the top of each of the plurality of first ribs 41 in a cross section perpendicular to the extending direction of the first ribs 41 and the cross section perpendicular to the extending direction of the second ribs 42 The radius of curvature of the top of each of the plurality of second ribs 42 in is set to be substantially equal to each other, for example.
In the case of this embodiment, as an example, each of the radius of curvature of the top of the first rib 41 and the radius of curvature of the top of the second rib 42 is preferably 0.01 mm or more and 0.2 mm or less, and more preferably, It is 0.05 mm or more and 0.1 mm or less.
Further, as an example, the protrusion height H3 of the first rib 41 (the protrusion height of the second rib 42) is preferably 0.05 mm or more and 1.5 mm or less, more preferably 0.1 mm or more and 1.5 mm or less. It is 0 mm or less.

In addition, in the above, the plurality of first ribs 41 and the plurality of second ribs 42 are respectively formed into upwardly convex protrusions, but the plurality of first ribs 41 and the plurality of second ribs 42 are The second ribs 42 may each be formed in the shape of a groove depressed downward. Further, one of the plurality of first ribs 41 and the plurality of second ribs 42 is formed into an upwardly convex protrusion, and the other is formed into a downwardly depressed groove. may have been done.

<Modified example of second embodiment>
Next, a modification of the second embodiment will be described using FIGS. 13(a) to 13(c). Note that in FIG. 13(b), illustration of the template 29 is omitted.
The plastic container 100 according to the present embodiment is different from the plastic container 100 according to the second embodiment described above in the following points, and the plastic container 100 according to the second embodiment described above is different from the plastic container 100 according to the second embodiment described above in other points. It is configured in the same way.

In the case of this modification, the second rib 42 is not formed on the inner surface 100b of the plastic container 100, but instead, a plurality of third ribs 50 are formed on the outer surface 100a of the plastic container 100. In plan view, the plurality of first ribs 41 and the plurality of third ribs 50 form a lattice shape.
More specifically, the first rib 41 is formed by pressing the uneven shape forming mold 300 on the surface opposite to the mold contact surface as described above, while the third rib 50 is For example, when the non-foamed sheet 80 is molded into a shape along the mold 200, it is formed by shaping the irregularities of the mold 200.
That is, in the present invention, the plastic container 100 has an uneven shape (third rib 50) formed on the mold contact surface by shaping the unevenness of the mold 200, and a metal mold for forming the uneven shape on the opposite surface. The uneven shape 20 formed on the opposite surface by pressing the mold 300 may be provided.
According to such a configuration, the shapes of both the inner surface 100b and the outer surface 100a of the plastic container 100 can be designed with a higher degree of freedom.

As shown in FIG. 13(b), each of the plurality of third ribs 50 is formed into a downwardly convex protrusion.
Each of the plurality of third ribs 50 extends, for example, in a direction that is inclined upward to the left in FIG. 13(a). Further, the plurality of third ribs 50 are arranged at equal intervals (equal angular intervals), for example, in the extending direction of the plurality of first ribs 41.
Further, as described above, the third ribs 50 are formed by shaping the unevenness of the mold 200, so as shown in FIG. A groove portion 56 is formed in the formation region 50 . Therefore, on the inner surface 100b of the plastic container 100, a lattice shape is formed by the plurality of grooves 56 and the plurality of first ribs 41.

In the case of this modification, as an example, the protrusion height H4 of the first rib 41 is preferably 0.05 mm or more and 1.5 mm or less, and more preferably 0.1 mm or more and 1.0 mm or less.
Further, as an example, the protrusion height H5 of the third rib 50 is preferably 0.05 mm or more and 1.5 mm or less, more preferably 0.1 mm or more and 1.0 mm or less.

[Third embodiment]
Next, a third embodiment will be described using FIGS. 14 to 15(b). Note that in FIG. 15(b), illustration of the template 29 is omitted.
The plastic container 100 according to the present embodiment is different from the plastic container 100 according to the first and second embodiments described above in the following points, and is different from the plastic container 100 according to the first and second embodiments described above in other points. It is configured similarly to the plastic container 100 according to the embodiment.

As shown in FIG. 15(b), in the case of this embodiment, the uneven shape 20 includes a stamp 60, and the radius of curvature of the corner 65 at the boundary between the stamp 60 and the edge 61 of the stamp 60 is The wall thickness is smaller than 100.
Thereby, the stamp 60 of a desired shape can be precisely and clearly formed. That is, it is possible to realize a plastic container 100 having a structure in which a fine shape is formed on the surface opposite to the mold contact surface.
Note that the radius of curvature here is the radius of curvature in a cross section along a direction perpendicular to the extending direction of the stamp 60 (for example, the cross section shown in FIG. 15(b)).
In addition, in the case of this embodiment, when measuring the curvature half shape of the corner 65 using the template 29, the template 29 is fitted into the corner 65 from approximately 45 degrees diagonally upward to 45 degrees diagonally downward. go.

In the example shown in FIGS. 14 to 15(b), the stamp 60 is a plurality of characters and is formed on the center portion 14a of the bottom surface portion 14. However, in the present invention, the stamp 60 may be a symbol in addition to letters, or may be a figure or a pattern.
As shown in FIG. 15(b), the stamp 60 is formed in the shape of a groove that is depressed downward. However, in the present invention, the stamp 60 may be a rib that is convex upward. The corner portion 65 of the stamp 60 has a rounded shape. The angle of the corner portion 65 is, for example, greater than or equal to 60 degrees and less than or equal to 100 degrees. Further, the radius of curvature of the corner 65 at the boundary with the edge 61 of the stamp 60 is, for example, preferably 0.01 mm or more and 0.2 mm or less, more preferably 0.05 mm or more and 0.1 mm or less. .
Further, the depth D1 of the stamp 60 is preferably 0.05 mm or more and 1.5 mm or less, more preferably 0.1 mm or more and 1.0 mm or less.

[Fourth embodiment]
Next, a fourth embodiment will be described using FIGS. 16(a) to 17(b).
The plastic container 100 according to the present embodiment is different from the plastic container 100 according to the first to third embodiments described above in the following points, and is different from the plastic container 100 according to the first to third embodiments described above in other respects. It is configured similarly to the plastic container 100.

In the case of this embodiment, an uneven shape 20 is formed on the upper surface 12a of the flange portion 12.
According to such a configuration, the contact area between the film-like lid portion (not shown) provided on the flange portion 12 and the upper surface 12a of the flange portion 12 can be made smaller. That is, on the upper surface 12a of the flange portion 12, the area where the heat seal is formed with respect to the lid portion can be made smaller, so that when the plastic container 100 is unsealed, the lid portion can be easily peeled off from the flange portion 12. be able to.
Furthermore, since a non-bonded region is formed in which a portion of the lid portion and a portion of the upper surface 12a are not bonded to each other, heat generation occurs when the plastic container 100 is heated in a microwave oven or the like via the non-bonded region. This allows the steam to escape (steam) from inside the main body portion 10.
Further, the plurality of uneven shapes 20 formed on the upper surface 12a of the flange portion 12 can also be used as a slip prevention member.

As shown in FIG. 16(b) and the like, in the case of this embodiment, the uneven shape 20 includes a plurality of minute recesses 70.
Each of the plurality of minute recesses 70 is formed to be depressed downward. Each of the plurality of minute recesses 70 is formed, for example, in a substantially conical shape that gradually decreases in size downward. Each of the plurality of minute recesses 70 is formed, for example, on substantially the entire upper surface 12a of the flange portion 12. However, the upper surface of the outer peripheral edge 12b of the flange portion 12 and the upper surface of a portion of the corner portion 12c of the flange portion 12 are regions in which the plurality of minute recesses 70 are not formed, respectively.

As shown in FIG. 17(b), the radius of curvature of the corner 75 at the boundary between the micro-recess 70 and the outer peripheral edge 71 of the micro-recess 70 is smaller than the wall thickness of the plastic container 100. Note that the radius of curvature here is the radius of curvature in a cross section cut along a line connecting the centers of adjacent minute recesses 70 (for example, line BB shown in FIG. 16(b)).
As a result, the corner 75 forming the opening 70a of the minute recess 70 can be formed into a steeper shape, so that the dimension of the opening 70a can be more reliably set to the intended size. Therefore, on the upper surface 12a of the flange portion 12, the balance between adhesiveness and releasability of the lid portion to the upper surface 12a can be easily achieved as intended.

In the case of this embodiment, as an example, the radius of curvature of the corner 75 at the boundary between the micro-recess 70 and the outer peripheral edge 71 of the micro-recess 70 is preferably 0.01 mm or more and 0.2 mm or less, more preferably is 0.05 mm or more and 0.1 mm or less.
As an example, the depth D2 of the minute recess 70 is preferably 0.05 mm or more and 1.5 mm or less, more preferably 0.1 mm or more and 1.0 mm or less.
Further, the inner diameter of the minute recess 70 is preferably 0.1 mm or more and 2.0 mm or less, more preferably 0.2 mm or more and 1.0 mm or less.

Although the embodiments have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above may also be adopted.

For example, in the first to fourth embodiments described above, an example has been described in which the mold contact surface is the outer surface 100a of the plastic container 100, and the opposite surface is the inner surface 100b of the plastic container 100. However, in the present invention, the mold contacting surface may be the inner surface 100b of the plastic container 100, and the surface opposite thereto may be the outer surface 100a of the plastic container 100. That is, the above-mentioned uneven shape 20 may be formed on the outer surface 100a of the plastic container 100. In this case, for example, the plastic container 100 is manufactured using a male mold.

Further, in the first to fourth embodiments described above, an example in which the uneven shape 20 is formed on the inner surface of the bottom surface of the plastic container 100 or the upper surface of the flange portion 12 has been described. The formation area of the uneven shape 20 on the surface opposite to the surface is not particularly limited, and for example, the uneven shape 20 may be formed on the inner surface (or outer surface) of the side peripheral wall of the main body part 10.

Further, in the first to fourth embodiments described above, an example was described in which the plastic container 100 includes only one of the microprotrusions 30, the ribs 40, the markings 60, and the microrecesses 70, but in the present invention, The plastic container 100 may include any two or more of the microprotrusions 30, the ribs 40, the markings 60, and the microrecesses 70.

This embodiment includes the following technical ideas.
(1) A plastic container manufactured by pressure forming or vacuum forming using a non-foamed sheet,
An uneven shape is formed on the surface opposite to the mold contact surface, which is the surface that comes into contact with the mold during molding.
The uneven shape is a plastic container having a corner portion having a radius of curvature smaller than the wall thickness of the plastic container.
(2) The plastic container according to (1), wherein the uneven shape is formed on the inner surface of the plastic container.
(3) The plastic container according to (2), wherein the uneven shape is formed on the inner surface of the bottom surface of the plastic container.
(4) The plastic container has a main body portion that accommodates the contents, and a flange portion that protrudes from the upper end opening of the main body portion,
The plastic container according to (1), wherein the uneven shape is formed on the upper surface of the flange portion.
(5) The plastic container according to any one of (1) to (4), wherein the mold contact surface does not have the uneven shape.
(6) The plastic container according to any one of (1) to (5), wherein the uneven shape includes a plurality of microprotrusions, and the radius of curvature of the top of the microprotrusions is smaller than the wall thickness.
(7) The plastic container according to any one of (1) to (6), wherein the uneven shape includes a rib, and the radius of curvature of the top of the rib is smaller than the wall thickness.
(8) The uneven shape includes a stamp, and the radius of curvature of the corner of the boundary between the stamp and the edge of the stamp is smaller than the wall thickness according to any one of (1) to (7). Plastic container as described.
(9) The non-foamed sheet has a laminate structure of three or more layers having a barrier layer as an intermediate layer,
The plastic container according to any one of (1) to (8), wherein the barrier layer is arranged offset toward the mold contacting surface side from a midpoint in the thickness direction of the non-foamed sheet. .
(10) The non-foamed sheet has a laminated structure having multiple layers,
The plastic container according to any one of (1) to (9), wherein the melt flow rate of the layer constituting the opposite surface among the plurality of layers is higher than the melt flow rate of the other layers.
(11) A method of manufacturing a plastic container by air pressure forming or vacuum forming, the method comprising:
a step of adsorbing a non-foamed sheet to a mold and molding the non-foamed sheet into a shape that follows the mold;
Pressing a mold for forming an uneven shape on the surface of the non-foamed sheet opposite to the mold contact surface that contacts the mold to transfer the uneven shape to the opposite surface;
Equipped with
In the step of transferring, the method for producing a plastic container includes forming, on the opposite surface, an uneven shape having corners having a radius of curvature smaller than the wall thickness of the plastic container.

10 Main body part 11 Body part 12 Flange part 12a Upper surface 12b Outer peripheral edge part 12c Corner part 13 Upper end opening 14 Bottom part 14a Center part 14b Peripheral part 14c Step part 16 Upper end part 17 Step part 20 Uneven shape 29 Template 30 Microprotrusion 35 Top part 37 Valley 40 Rib 41 First rib 42 Second rib 45 Top 50 Third rib 55 Top 56 Groove 60 Stamp 61 Edge 65 Corner 70 Minute recess 70a Opening 71 Outer edge 75 Corner 80 Non-foamed sheet 80a One side (mold contact surface)
80b Other side (opposite side)
81 Barrier layer (intermediate layer)
82 First base layer 83 Second base layer 84 First adhesive layer 85 Second adhesive layer 86 Surface layer 87 Third base layer 90 Curved shape 100 Plastic container 100a Outer surface 100b Inner surface 200 Mold 300 Metal for forming uneven shape Mold 400 Plastic container 400a Mold contact surface 400b Opposite surface 420 Uneven shape 430 Protrusion 435 Top 436 Recess 437 Valley

Claims (11)

A plastic container manufactured by pressure forming or vacuum forming using a non-foamed sheet,
An uneven shape is formed on the surface opposite to the mold contact surface, which is the surface that comes into contact with the mold during molding.
The uneven shape is a plastic container having a corner portion having a radius of curvature smaller than the wall thickness of the plastic container. The plastic container according to claim 1, wherein the uneven shape is formed on the inner surface of the plastic container. The plastic container according to claim 2, wherein the uneven shape is formed on the inner surface of the bottom surface of the plastic container. The plastic container has a main body portion that accommodates contents, and a flange portion that protrudes from an upper end opening of the main body portion,
The plastic container according to claim 1, wherein the uneven shape is formed on the upper surface of the flange portion. The plastic container according to any one of claims 1 to 4, wherein the mold contact surface does not have the uneven shape. The plastic container according to any one of claims 1 to 4, wherein the uneven shape includes a plurality of microprotrusions, and the radius of curvature of the top of the microprotrusions is smaller than the wall thickness. The plastic container according to any one of claims 1 to 4, wherein the uneven shape includes a rib, and the radius of curvature of the top of the rib is smaller than the wall thickness. The plastic container according to any one of claims 1 to 4, wherein the uneven shape includes a stamp, and a radius of curvature of a corner of a boundary between the stamp and an edge of the stamp is smaller than the wall thickness. The non-foamed sheet has a laminate structure of three or more layers having a barrier layer as an intermediate layer,
The plastic container according to any one of claims 1 to 4, wherein the barrier layer is offset from a midpoint in the thickness direction of the non-foamed sheet toward the mold contact surface side. The non-foamed sheet has a laminated structure having multiple layers,
The plastic container according to any one of claims 1 to 4, wherein the melt flow rate of the layer constituting the opposite surface among the plurality of layers is higher than the melt flow rate of the other layers. A method of manufacturing a plastic container by air pressure forming or vacuum forming, the method comprising:
a step of adsorbing a non-foamed sheet to a mold and molding the non-foamed sheet into a shape that follows the mold;
Pressing a mold for forming an uneven shape on the surface of the non-foamed sheet opposite to the mold contact surface that contacts the mold to transfer the uneven shape to the opposite surface;
Equipped with
In the step of transferring, the method for producing a plastic container includes forming, on the opposite surface, an uneven shape having corners having a radius of curvature smaller than the wall thickness of the plastic container.

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