JP2020157523A - Mold for molding in-mold label container and in-mold label container - Google Patents

Abstract

To provide a mold for molding an in-mold label container capable of molding the in-mold label container having higher oxygen barrier property than ever.SOLUTION: A mold 200 is used for injection-molding an in-mold label container comprising: a bottom wall; a peripheral wall; a flange; and an in-mold label integrated to an outer peripheral surface of the peripheral wall. The mold comprises a first mold 20 with a first cavity surface 20a, and a second mold 30 with a second cavity surface 30a, and a cavity is formed between the first cavity surface and the second cavity surface. The first cavity surface of the first mold includes: a peripheral wall outer cavity surface 22 corresponding to the outer peripheral surface of the peripheral wall; a flange rear cavity surface 23 corresponding to a back surface of the flange; and a short-circuit cavity surface 25 disposed between the peripheral wall outer cavity surface and the flange rear cavity surface. The short-circuit cavity surface is configured in such a manner that a thickness of a peripheral wall cavity part corresponding to the peripheral wall in the cavity is gradually thickened toward the flange rear cavity surface.SELECTED DRAWING: Figure 6

Description

The present invention relates to an in-mold label container molding die and an in-mold label container. More specifically, the in-mold label is inserted when the container is injection-molded with the mold, and the in-mold label is inserted onto the peripheral wall of the container at the same time as the injection molding. The present invention relates to a mold for injection molding an in-mold label container formed by heat-sealing a mold label, and an in-mold label container that can be molded with such a mold.

In-mold molding, in which a film-shaped in-mold label is heat-sealed onto the outer peripheral surface of the peripheral wall of the container when the container is injection-molded, is more efficient than retrofitting the label to the container because the manufacturing process is more efficient. It is commonly done. The in-molded container is called an in-mold label container, and generally includes a bottom wall, a tubular peripheral wall, and a flange protruding from the upper end of the peripheral wall toward the outer peripheral side. The upper end opening surrounded by the flange of the container is opened, and a lid is separately provided at the upper end opening. The in-mold label can impart an oxygen barrier property to the container to reduce oxygen permeation between the inside and outside of the container, and this performance is particularly important when the content of the container is food or the like.

FIG. 13 is a cross-sectional view schematically showing the mold open state of the conventional fixed mold 120 and the movable mold 130. Hereinafter, unless otherwise specified, the description based on FIGS. 13 to 17 shall be based on the paper pages of FIGS. 13 to 17 in the left-right direction. The fixed mold 120 and the movable mold 130 are horizontally arranged concentrically with the axis H, and the movable mold 130 advances and retreats with respect to the fixed mold 120 fixedly arranged on the left side to close and open the mold. The fixed mold 120 has a fixed cavity surface 120a, and the movable mold 130 has a movable cavity surface 130a. The fixed cavity surface 120a includes a bottom wall outer cavity surface 121 corresponding to the outer surface of the bottom wall of the container, a peripheral wall outer cavity surface 122 corresponding to the outer peripheral surface of the peripheral wall, and a flange back cavity surface 123 corresponding to the back surface of the flange. And include. The movable cavity surface 130a includes a bottom wall inner cavity surface 131 corresponding to the inner surface of the bottom wall of the container, a peripheral wall inner cavity surface 132 corresponding to the inner peripheral surface of the peripheral wall, and a flange surface cavity surface corresponding to the flange surface. Includes 133 and. In in-mold molding, the label 110 in a tubular shape is inserted into the fixed mold 120 as shown in FIG. 13 and set on the peripheral wall outer cavity surface 122. Next, the movable mold 130 is brought close to the fixed mold 120 and the mold is closed. A cavity is formed between the fixed cavity surface 120a of the fixed mold 120 and the movable cavity surface 130a of the movable mold 130. By filling the cavity with molten resin, the label is integrated on the outer peripheral surface of the peripheral wall of the container, and the in-mold label container is injection-molded. At the time of this injection molding, the label 110 is set on the peripheral wall outer cavity surface 122 of the fixed mold 120. At this time, the right end portion 110a of the label 110 is arranged on the movable type 130 side with respect to the peripheral wall outer cavity surface 122. The right end portion 110a of the label 110 is bent onto the flange back cavity surface 123 by the filling resin for the cavity so as to cover the back surface of the flange. However, at this time, there are the following problems.

FIG. 14 is a partially enlarged cross-sectional view schematically showing the cavity of the flange when the fixed mold 120 and the movable mold 130 are closed. Further, FIG. 14 shows a state before filling the cavity with resin. In FIG. 14, Ca is a peripheral wall cavity portion corresponding to the peripheral wall of the container in the cavity, and Cb is a flange cavity portion corresponding to the flange of the container. The flange cavity portion Cb extends radially outward from the right end portion of the peripheral wall cavity portion Ca. The cavity also includes a bottom wall cavity portion (not shown) corresponding to the bottom wall of the container.

FIG. 15 is a partially enlarged cross-sectional view showing a state in which the cavity including the peripheral wall cavity portion Ca and the flange cavity portion Cb is filled with resin from the state of FIG. In the state of FIG. 14, the right end portion 110a of the label 110 is detached from the peripheral wall outer cavity surface 122 of the fixed mold 120, and protrudes from the flange back cavity surface 123 to the right flange cavity portion Cb by the length L1. The protruding length L1 is set to a length up to the flange surface cavity surface 133 of the movable mold 130 in the mold closed state. The right end portion 110a of the label 110 is pushed toward the flange cavity portion Cb side by filling with the molten resin. Therefore, as shown in FIG. 15, it is bent outward in the radial direction on the flange side and is arranged on the flange back cavity surface 123. As a result, the right end portion 110a of the label 110 comes to the back surface of the flange of the molded container.

However, when the length L2 (see FIG. 14) along the radial direction of the flange back cavity surface 123 is longer than the protruding length L1 of the right end portion 110a of the label 110, the label 110 is the flange back as shown in FIG. It does not reach the radial outer end 124 of the cavity surface 123. Therefore, a portion not covered with the label 110 remains on the radial outer side of the back surface of the flange of the container. In this case, since oxygen is allowed to permeate from the radial outer portion deviating from the label 110 on the back surface of the flange, the oxygen barrier property of the container is lowered. In order to prevent this, it is conceivable to make the protruding length of the right end portion 110a of the label 110 longer than the radial length L2 of the flange back cavity surface 123.

FIG. 16 is a partially enlarged cross section showing a case where the protruding length of the right end portion 110a of the label 110 is set to a protruding length L1'which is longer than the protruding length L1 of FIG. Here, the protruding length of the right end portion 110a of the label 110 is the protruding length of the right end portion 110a of the label 110 from the flange back cavity surface 123. FIG. 16 is a partially enlarged cross-sectional view showing a state of the fixed mold 120 and the movable mold 130 immediately before the mold is closed, and shows a time point when the right end of the label 110 is in contact with the movable mold 130. FIG. 17 is a partially enlarged cross-sectional view showing a state in which the mold is closed from the state of FIG. As shown in FIG. 16, in the case of the label 110 whose protrusion length is set to L1'which is longer than L1, the right end of the label 110 is the flange of the movable mold 130 just before the fixed mold 120 and the movable mold 130 are closed. The movable mold 130 is in contact with the front cavity surface 133, and the right end of the label 110 is pushed to the left to close the mold. Therefore, as shown in FIG. 17, the label 110 may be wrinkled due to buckling or randomly bending in and out of the radial direction. Therefore, in the conventional fixed mold 120 and the movable mold 130, the point where the right end portion 110a of the label 110 is more spread on the flange back cavity surface 123 of the fixed mold 120 and the back surface of the flange of the container to be molded are in-molded. There was a limitation in covering more with the label.

Japanese Unexamined Patent Publication No. 2003-173144 (Patent Document 1) describes a technique for making it easier for the label to cover the back surface of the flange of the container during injection molding of the container by making a cut or a perforation in advance in the flange-corresponding portion of the in-mold label. Has been proposed.

Japanese Unexamined Patent Publication No. 2003-173144

However, in the label disclosed in Patent Document 1, the flange-compatible portion tends to bend not only radially outside but also radially inside during injection molding, and it is difficult to successfully arrange the entire flange-compatible portion of the label on the back surface of the flange. In addition, there is a problem that the cut in the label portion that comes to the back surface of the flange of the container widens to form a gap, and the oxygen barrier property is impaired.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a mold for molding an in-mold label container capable of molding an in-mold label container having a higher oxygen barrier property than before. To do.

One in-mold label container molding die of the present invention capable of solving such a problem protrudes from the bottom wall, the peripheral wall, and the end of the peripheral wall in the axial direction opposite to the bottom wall to the outer peripheral side. A mold for injection molding an in-mold label container including a flange and an in-mold label integrated on the outer peripheral side of the peripheral wall, and the mold is a first mold having a first cavity surface. A second mold having a second cavity surface is provided, and a cavity for molding the in-mold label container is formed between the first cavity surface and the second cavity surface, and the first mold is said to have a cavity. The first cavity surface includes a peripheral wall outer cavity surface corresponding to the outer peripheral surface of the peripheral wall, a flange back cavity surface corresponding to the back surface of the flange on the bottom wall side in the axial direction, and the peripheral wall outer cavity surface and the flange. The short-circuit cavity surface includes a short-circuit cavity surface provided between the back cavity surface and the peripheral wall cavity portion corresponding to the peripheral wall in the cavity so as to gradually increase the thickness of the peripheral wall cavity portion to the flange back cavity surface. Is to be done.

In addition, one in-mold label container that can solve the above-mentioned problems includes a bottom wall, a peripheral wall, a flange protruding from an end opposite to the bottom wall in the axial direction of the peripheral wall to the outer peripheral side, and the peripheral wall. An in-mold label container including an in-mold label integrated with the outer peripheral surface of the flange, the thickness of the peripheral wall between the outer peripheral surface of the peripheral wall and the back surface of the flange on the bottom wall side in the axial direction. It is provided with a thick portion that gradually increases the thickness of the label toward the flange.

According to the present invention, it is possible to provide an in-mold label container molding mold capable of enhancing the oxygen barrier property of the container.

According to the present invention, it is possible to provide an in-mold label container capable of enhancing the oxygen barrier property of the container.

FIG. 1 is a front view of an in-mold label container according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the box A portion of FIG. FIG. 3 is a cross-sectional view similar to FIG. 2 showing a modified example of the thick portion. FIG. 4 is a partial cross-sectional side view schematically showing an injection molding apparatus to which an in-mold label container molding die according to the present invention is attached. FIG. 5 is an overall view schematically showing an in-mold molding system including a mold for molding an in-mold label container according to the present invention. FIG. 6 is a cross-sectional view schematically showing the mold open state of the fixed type (first type) and the movable type (second type). FIG. 7 is a cross-sectional view schematically showing a fixed mold and a movable mold in a closed mold state. FIG. 8 is an enlarged cross-sectional view of the portion of the box A'in FIG. FIG. 9 is a partially enlarged cross-sectional view showing a state in which the cavity is filled with the molten resin from the state of FIG. FIG. 10 is a partially enlarged cross-sectional view showing a state immediately before closing the fixed mold and the movable mold, and shows a time point when the movable mold side end of the label comes into contact with the movable mold. FIG. 11 is a partially enlarged cross-sectional view showing a fixed type and a movable type in a closed state and before resin filling. FIG. 12 is a partially enlarged cross-sectional view showing a state in which the resin is filled from the state of FIG. FIG. 13 is a cross-sectional view schematically showing a conventional fixed type and movable type mold open state. FIG. 14 is a partially enlarged cross-sectional view showing a conventional fixed type and movable type in a closed state and before resin filling. FIG. 15 is a partially enlarged cross-sectional view showing a state in which the resin is filled from the state of FIG. FIG. 16 is a partially enlarged cross-sectional view showing a state immediately before closing the conventional fixed type and movable type, and shows a time point when the right end of the label having a longer protruding length than the label of FIG. 14 comes into contact with the movable type. .. FIG. 17 is a partially enlarged cross-sectional view showing a state in which the mold is closed from the state of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to such embodiments, and can be appropriately modified within the scope of claims and the equivalent.

FIG. 1 is a front view of an in-mold label container (hereinafter, also simply referred to as “container”) 1 according to an embodiment of the present invention. As an example, the container 1 has a disk-shaped bottom wall 2, a peripheral wall 3 extending in a cylindrical shape from the peripheral edge of the bottom wall 2, and an end (upper end) opposite to the bottom wall 2 in the axial direction along the axis B of the peripheral wall 3. ) With a flange 4 protruding outward in the radial direction with respect to the axis B. Unless otherwise specified, the description of the container 1 below shall be based on the pages of FIGS. 1 to 3 in the vertical direction. The container 1 has an open upper end opening surrounded by a flange 4. The peripheral wall 3 slightly expands in diameter upward. An in-mold label (hereinafter, also simply referred to as “label”) 10 is integrated with the outer peripheral surface 3a of the peripheral wall 3 of the container 1 and the back surface (lower surface) 4a of the flange 4 shown in FIG. 1 during injection molding of the container 1. Is heat-sealed to. The shape of the bottom wall 2 is not limited to a disk shape. Further, the peripheral wall 3 extends in a tubular shape from the bottom wall 2. This tubular shape includes not only a cylindrical cylinder but also a rectangular cylinder. In other words, the tubular shape includes not only a circular cross section but also a rectangular cross section, an elliptical cross section, an oblong cross section, a polygonal cross section, and an annular shape having a straight line and a curved cross section. The shape of the peripheral wall 3 may be such that the label 10 can be integrally molded without causing wrinkles or the like. In this example, the inclination angle of the peripheral wall 3 is set to an angle at which the label 10 is less likely to wrinkle during injection molding in consideration of the strength of the label 10.

FIG. 2 is an enlarged cross-sectional view taken along the axis B of the box A portion of FIG. The container 1 has the following thick portion 5 between the outer peripheral surface 3a of the peripheral wall 3 and the back surface 4a of the flange 4. That is, the thick portion 5 starts to become thicker when the thickness of the peripheral wall 3 in the radial direction is applied to the thick portion 5 near the flange 4. Further, the thick portion 5 is formed so as to reach the back surface 4a of the flange 4 while gradually increasing in thickness upward. The thick portion 5 is a portion formed by the short-circuit cavity surface 25 in the mold according to the present invention described later. In the present embodiment, the outer peripheral surface 5a of the thick portion 5 is a surface that linearly connects the outer peripheral surface 3a of the peripheral wall 3 and the back surface 4a of the flange 4 in a cross section along the axis B. More specifically, with reference to FIG. 2, the cross-sectional shape of the thick portion 5 is a triangle surrounded by the outer peripheral surface 5a of the thick portion 5, the virtual extension surface 3a', and the virtual extension surface 4a'. .. The virtual extension surface 3a'is a surface obtained by extending the outer peripheral surface 3a of the peripheral wall 3 to the flange 4 when it is assumed that there is no thick portion 5. The virtual extension surface 4a'is a surface obtained by extending the back surface 4a of the flange 4 to the peripheral wall 3 when it is assumed that there is no thick portion 5. In the present embodiment, the length of the virtual extension surface 3a'is longer than the length of the virtual extension surface 4a'. The connecting portion between the outer peripheral surface 3a of the peripheral wall 3 and the outer peripheral surface 5a of the thick portion 5 is 5b, and the connecting portion between the outer peripheral surface 5a of the thick portion 5 and the back surface 4a of the flange 4 is 5c. The length from the connecting portion 5b to the connecting portion 5c via the outer peripheral surface 5a of the thick portion 5 is shorter than the length from the connecting portion 5b to the connecting portion 5c via the virtual extension surface 3a'and the virtual extension surface 4a'. .. For this reason, since the container 1 is provided with the thick portion 5, the label 10 is thick so as to reach the back surface 4a of the flange 4 from the outer peripheral surface 3a of the peripheral wall 3 through the outer peripheral surface 5a of the thick portion 5. It can be short-circuited at the meat portion 5. In the example of FIG. 2, the label 10 covers the entire back surface 4a of the flange 4 of the container 1, and also covers the lower half of the end surface 4c on the radial outer side of the flange 4. As a result, the oxygen barrier property of the container 1 is enhanced. Even if the label 10 does not cover the entire back surface 4a of the flange 4, the outer peripheral surface 3a of the peripheral wall 3 and the back surface 4a of the flange 4 can be short-circuited by the outer peripheral surface 5a of the thick portion 5. The label 10 makes it possible to cover the back surface 4a of the flange 4 more widely outward in the radial direction. Further, the thick portion 5 increases the strength of the portion between the peripheral wall 3 of the container 1 and the flange 4. The connection portion 5c between the outer peripheral surface 5a of the thick portion 5 and the back surface 4a of the flange 4 in FIG. 2 is in the radial direction of the connection portion P between the virtual extension surface 3a'and the virtual extension surface 4a'and the back surface 4a of the flange 4. Comes radially outside the midpoint between the outer edge 4b and.

FIG. 3 is a cross-sectional view showing a modified example of the thick portion 5, and is an enlarged cross-sectional view similar to that of FIG. The same reference number is used for the parts substantially in common with FIG. As shown in FIG. 3, the outer peripheral surface 5'a of the thick portion 5'has a curved cross-sectional shape that is slightly concave inward in the radial direction. In other words, the outer peripheral surface 5'a of the thick portion 5'has a curved cross-sectional shape that is slightly concavely recessed on the connection portion P side. Therefore, the thick portion 5'becomes gently thickened along the radial direction from the outer peripheral surface 3a of the peripheral wall 3, and is gently connected to the back surface 4a of the flange 4. In this example, the label 10'from the outer peripheral surface 3a of the peripheral wall 3 to the back surface 4a of the flange 4 via the outer peripheral surface 5'a of the thick portion 5'. The end 10d of the label 10'is located at a position slightly inward in the radial direction from the outer end 4b on the back surface 4a of the flange 4. Assuming that there is no thick portion 5', the position of the end 10d'of the label 10'is a substantially intermediate portion on the virtual extension surface 4a'of the flange 4. The connection between the outer peripheral surface 3a of the peripheral wall 3 and the outer peripheral surface 5'a of the thick portion 5'is 5'b, and the connection portion between the outer peripheral surface 5'a of the thick portion 5'and the back surface 4a of the flange 4 is formed. Let it be 5'c. The length from the connecting portion 5'b to the connecting portion 5'c via the outer peripheral surface 5'a of the thick portion 5'is from the connecting portion 5'b via the virtual extension surface 3a'and the virtual extension surface 4a'. It is shorter than the length of the connection part up to 5'c. Therefore, the position of the end 10d of the label 10'is radially outside the position of the end 10d' of the label 10'assuming that there is no thick portion 5'. For this reason, since the container 1 in this example is provided with the thick portion 5', the label 10'is attached to the flange 4 from the outer peripheral surface 3a of the peripheral wall 3 via the outer peripheral surface 5'a of the thick portion 5'. It can be short-circuited at the thick portion 5'so as to reach the back surface 4a.

In the container according to the present invention, the cross-sectional shape of the outer peripheral surface of the thick portion is not limited to the linear shape shown in FIG. 2 and the concave curved shape shown in FIG. 3, for example, one or a plurality of straight lines and /. Alternatively, one or a plurality of concave curved lines may be combined to form an overall cross section close to the linear shape of FIG. 2 or the concave curved shape of FIG. The thick portion having such an outer peripheral surface cross section is formed by the short-circuit cavity surface 25 in the mold of the present invention described later. As will be described later, the short-circuit cavity surface 25 has a cross-sectional shape such that the label 10 is arranged along the short-circuit cavity surface 25 without causing wrinkles during injection molding. In other words, the cross-sectional shape of the outer peripheral surface of the thick portion corresponds to the cross-sectional shape of the short-circuit cavity surface 25 that the label 10 can follow without wrinkling during injection molding.

FIG. 4 is a partial cross-sectional side view schematically showing an injection molding machine 100 that injection-molds a container 1 with an in-mold label container molding die 200 (hereinafter, also simply referred to as “mold”) according to the present invention. Is. The in-mold label container molding die 200 according to the present invention is detachably attached to the injection molding machine 100. The mold 200 includes a fixed mold 20 as a first mold and a movable mold 30 as a second mold. FIG. 4 shows the mold closed state of the fixed mold 20 and the movable mold 30. In the mold closed state, a cavity C, which is a space for injection molding the container 1, is formed between the fixed mold 20 and the movable mold 30. Hereinafter, in the description of the injection molding machine 100, the left-right direction based on the paper surface of FIG. 4 is a mold opening / closing direction for closing and opening the mold 200. The injection molding machine 100 constitutes an in-mold label container injection molding system 201 together with the mold 200 according to the present invention. The injection molding machine 100 includes an injection device 40 that injects molten molding material into the cavity C between the fixed mold 20 and the movable mold 30, a moving device 50 that moves the injection device 40 back and forth with respect to the fixed mold 20. It is provided with a mold clamping device 60 for moving the movable mold 30 in the front-rear direction with respect to the fixed mold 20 to open and close the mold, and an ejector device 70 for taking out a container 1 which is a molded product from the movable mold 30 in the mold open state. .. The injection device 40, the moving device 50, the mold clamping device 60, and the ejector device 70 are arranged on the upper frame 102 in the base 101 of the injection molding machine 100. In the description of the injection device 40 and the moving device 50, the moving direction of the screw when filling the molding material will be described as the front, and the moving direction of the screw when weighing the molding material will be described as the rear. In the description of the mold clamping device 60 and the ejector device 70, the moving direction of the movable mold when the mold is closed will be described as the front, and the moving direction of the movable mold when the mold is opened will be described as the rear.

The injection device 40 has a cylinder 41 extending toward the fixed mold 20, a screw 42 arranged concentrically with the cylinder 41 inside the cylinder 41, and a screw spirally provided around the cylinder 41, and an outer peripheral side of the cylinder 41. A band-shaped heater 43 arranged so as to surround the periphery thereof, and a motor box 44 arranged on the rear side of the cylinder 41 and the screw 42 are provided. Although not shown, a metering motor that rotates the screw 42 around the central axis, an injection motor that displaces the screw 42 in the front-rear direction, and the like are arranged in the motor box 44. The metering motor rotates the screw 42 to melt the molding material in the cylinder 41 and feeds the cylinder 41 forward. A supply port 41a to which a hopper for charging a molding material into the cylinder 41 can be attached is provided at the rear portion of the cylinder 41. Further, a nozzle 45 having a reduced diameter and abutting on a fixed platen 61, which will be described later, is provided at the tip of the cylinder 41. The molding material introduced into the cylinder 41 from the supply port 41a is heated and melted by the heater 43 and conveyed forward by the screw 42. When a predetermined amount of molten resin is accumulated at the tip of the cylinder 41, it is ejected from the nozzle 45 into the cavity C through the passage 20b (see FIG. 6 and the like) provided in the fixed mold 20.

The moving device 50 is provided, for example, in the lower part of the motor box 44 of the injection device 40, and can move the injection device 40 back and forth with respect to the fixed platen 61 described later. As an example, the moving device 50 includes a hydraulic cylinder 53 fixed to the injection device 40, and a piston rod 54 having one end fixed to the fixed platen 61 and the other end housed in the hydraulic cylinder 53. .. The injection device 40 is movable with respect to the linear guide 51 fixed on the upper frame 102 via the slide base 52. The moving device 50 allows the injection device 40 to approach or separate from the mold 200 side, which allows, for example, the nozzle 45 of the injection device 40 to be pressed against the fixed platen 61 at a predetermined pressure.

The mold clamping device 60 includes a fixed platen 61 to which the fixed mold 20 is detachably fixed, a movable platen 62 to which the movable mold 30 is detachably fixed, and a platen moving mechanism 63 for moving the movable platen 62 back and forth. Be prepared. The platen moving mechanism 63 includes a rear platen 64 arranged on the upper frame 102, a mold clamping motor 65 provided on the back surface of the rear platen 64, and a motion conversion mechanism for converting the rotational motion of the mold clamping motor 65 into a linear motion in the front-rear direction. It includes 66 and a toggle mechanism 67 that increases the force transmitted to the motion conversion mechanism 66 and transmits it to the movable platen 62. The toggle mechanism 67 is formed by oscillating a plurality of links 67a to 67c connecting the output portion of the rear platen 64 and the motion conversion mechanism 66 and the movable platen 62 with a pin. Reference numeral 68 in FIG. 4 is a plurality of tie bars that connect the fixed platen 61 and the rear platen 64.

The ejector device 70 includes an ejector motor 73, a motion direction changing mechanism 72 that converts the rotational motion of the ejector motor 73 into a linear motion, and a movable member 71 that advances and retreats by the motion direction changing mechanism 72. The container 1, which is a molded product held by the movable mold 30 in the open mold state, is pushed forward through the movable member 71 by the stripper 30B described as a part of the movable mold 30 in the present specification, and will be described later. The container 1 is sucked into the suction cup 91 of the container take-out unit 90 (see FIG. 5).

FIG. 5 schematically shows an in-mold molding system including a unit for supplying a label 10 to a mold 200 according to the present invention and a unit for taking out a container 1 which is a molded product from the mold 200 and carrying it out to the next step. It is an overall view shown in. The in-mold molding system includes the injection molding machine 100 described above. In FIG. 5, only a part of the injection molding machine 100 is shown. A part of the in-mold molding system is disclosed in JP-A-2010-99914. The fixed mold 20 is fixed to the fixed platen 61 of the mold clamping device 60, and the movable mold 30 is fixed to the movable platen 62. By moving the movable platen 62 back and forth by the platen moving mechanism 63 described above, the movable mold 30 can move between the mold opening position and the mold closing position in the front-back direction. The in-mold molding system is an in-molded product after being molded and cooled by a label supply unit 80 for supplying a label 10 wound in a tubular shape into a cavity of a fixed mold 20 and a mold 200. It includes a container take-out unit 90 for taking out the mold label container 1 from the movable mold 30 and transporting it to the next step. The mold 200 according to the present invention constitutes the in-mold label container molding system 202 together with the label supply unit 80.

The label supply unit 80 includes a pseudo core 81 having substantially the same outer shape as the core 30A of the movable mold 30, which will be described later, an arm 82 for rotating the pseudo core 81 around the axis F, and an axis of the mold for the pseudo core 81. It is provided with a moving mechanism 83 that moves horizontally along B'. The pseudo core 81 receives the label 10 from a label feeder (not shown) at the label receiving position shown by the solid line in FIG. 5, and winds it in a tubular shape around the outer peripheral surface of the pseudo core 81. The pseudo core 81 in this state is then swiveled around the axis F by the arm 82 and moves to a position concentric with the axis B'. Next, the pseudo core 81 is moved forward by the moving mechanism 83, and the label 10 is delivered to the cavity portion of the fixed mold 20.

The container take-out unit 90 horizontally moves the suction cup 91 capable of sucking the container 1 from the bottom wall 2, the arm 92 for rotating the suction cup 91 around the axis G, and the suction cup 91 along the axis B'of the mold. It is provided with a moving mechanism 93 for making the movement. The container 1, which is a molded product after being molded and cooled by the mold, moves to the mold opening position while being held by the movable mold 30. The ejector device 70 described above operates at this mold opening position. As a result, the stripper 30B, which will be described later, which is a part of the movable type 30, moves forward and pushes the container 1 forward. This container 1 is delivered to the suction cup 91 shown by the broken line in FIG. The suction cup 91 moves forward together with the container 1 by the moving mechanism 93. Next, the suction cup 91 is swiveled around the axis F by the arm 92 and moves to the discharge position indicated by the solid line. At this discharge position, the container 1 is discharged to a transport mechanism or the like.

FIG. 6 is an enlarged cross-sectional view of the fixed mold 20 and the movable mold 30 in the open mold state. The fixed mold 20 and the movable mold 30 are arranged concentrically with respect to the axis B'. The fixed mold 20 has a fixed cavity surface 20a as a first cavity surface. The fixed cavity surface 20a corresponds to the bottom wall outer cavity surface 21 corresponding to the outer surface of the bottom wall 2 of the container 1, the peripheral wall outer cavity surface 22 corresponding to the outer peripheral surface 3a of the peripheral wall 3, and the back surface 4a of the flange 4. Flange back cavity surface 23, flange end cavity surface 24 corresponding to the flange back cavity surface 23 side half portion in the radial outer end surface 4c of the flange 4, and short-circuit cavity surface corresponding to the outer peripheral surface 5a of the thick portion 5. It consists of 25. Reference number 26 is the movable type 30 side end face of the fixed type 20. Assuming that there is no short-circuit cavity surface 25, the short-circuit cavity surface 25 is a surface that removes the corners existing between the peripheral wall outer cavity surface 22 and the flange back cavity surface 23 to short-circuit the two. I can say. The diameter of the peripheral wall outer cavity surface 22 with respect to the axis B'slightly expands to the short-circuit cavity surface 25, and the cross section is inclined. The diameter of the short-circuit cavity surface 25 with respect to the axis B'is gradually expanded to the flange back cavity surface 23, and the cross section is inclined. The expansion ratio of both is larger on the short-circuit cavity surface 25, and therefore, the inclination of the cross section is steeper on the short-circuit cavity surface 25.

The movable mold 30 has a movable cavity surface 30a as a second cavity surface. The movable cavity surface 30a corresponds to the bottom wall inner cavity surface 31 corresponding to the inner surface of the bottom wall 2 of the container 1, the peripheral wall inner cavity surface 32 corresponding to the inner peripheral surface of the peripheral wall 3, and the surface of the flange 4. It has a flange front cavity surface 33 and a flange end cavity surface 34 corresponding to the flange front cavity surface 33 side half of the end surface 4c of the flange 4. Further, the movable type 30 is composed of a core 30A and a stripper 30B arranged around the rear end portion of the core 30A. The core 30A is provided with a cavity surface 31 in the bottom wall and a cavity surface 32 in the peripheral wall. The stripper 30B is provided with a flange front cavity surface 33 and a flange end cavity surface 34. Reference number 35 is a contact / separation surface with the fixed mold 20. When the contact / separation surface 35 comes into contact with the movable mold 30 side end surface 26 of the fixed mold 20, the fixed mold 20 and the movable mold 30 are in a mold closed state. In the present embodiment, the fixed mold 20 and the movable mold 30 are provided with the flange end cavity surfaces 24 and 34, respectively, but the present invention is not limited to this. Flange end cavity surfaces 24 and 34 may be provided on only one of the fixed mold 20 and the movable mold 30.

FIG. 7 is a cross-sectional view schematically showing a fixed mold 20 and a movable mold 30 in a mold closed state. In the fixed mold 20 and the movable mold 30, in the closed state, a cavity C, which is a space corresponding to the shape of the container 1, is formed between the fixed cavity surface 20a and the movable cavity surface 30a. The cavity C is filled with molten resin from the injection device 40 via the passage 20b of the fixed mold 20, and the container 1 is formed. The cavity C includes a bottom wall cavity portion C2 corresponding to the bottom wall 2 of the container 1, a peripheral wall cavity portion C3 corresponding to the peripheral wall 3 of the container 1, and a flange cavity portion C4 corresponding to the flange 4. The short-circuit cavity surface 25 is configured so that the thickness of the peripheral wall cavity portion C3 along the radial direction is gradually increased toward the flange back cavity surface 23.

In the present embodiment, the short-circuit cavity surface 25 is a surface for forming the thick portion 5 shown in FIG. The thick portion 5 has an outer peripheral surface 5a having a substantially straight cross section. In order to form such a thick portion 5, the short-circuit cavity surface 25 has a substantially linear cross section along the axis B'. Although not shown, the cross section of the short-circuit cavity surface can be a curved line that is convex inward in the radial direction. The thick portion 5'shown in FIG. 3 can be formed by the short-circuit cavity surface having such a cross-sectional shape. The thick portion 5'has an outer peripheral surface 5'a having a concave curved linear cross section. The short-circuit cavity surface is not limited to these examples. The short-circuit cavity surface 25 may have a cross-sectional shape such that the label 10 is arranged along the short-circuit cavity surface 25 without causing wrinkles during injection molding. The cross section of the short-circuit cavity surface 25 is, for example, a cross section that is close to the linear shape of FIG. 2 or the concave curved shape of FIG. 3 as a whole by combining one or more straight lines and / or one or more convex curved lines. can do.

With reference to FIG. 6, the label 10 wound in a tubular shape by the label supply unit 80 is inserted and arranged in the cavity of the fixed mold 20 when the mold is opened. At this time, the label 10 is set so as to be in close contact with the peripheral wall outer cavity surface 22 of the fixed mold 20 by utilizing intake air or electrostatic adsorption. In this label set state, the end portion of the label 10 on the bottom wall outer cavity surface 21 side is generally in contact with the bottom wall outer cavity surface 21 of the fixed mold 20, but may be separated from the bottom wall outer cavity surface 21. Further, in the label set state, the label 10 maintains a tubular shape having a linear cross section along the peripheral wall outer cavity surface 22 up to the end on the flange back cavity surface 23 side, whereby the portion 10b on the flange back cavity surface 23 side of the label 10 is formed. It is separated from the short-circuit cavity surface 25. The portion of the label 10 on the flange back cavity surface 23 side (hereinafter, referred to as “label end portion”) 10b is flanged more than the flange back cavity surface 23 side end 22a of the peripheral wall outer cavity surface 22 in the set label 10. The portion on the back cavity surface 23 side.

Next, a step of molding the in-mold label container 1 using the mold 200 according to the present invention will be described. Hereinafter, in order to explain the advantages of the present invention in an easy-to-understand manner, the conventional fixed type 120 and the movable type 130 shown in FIGS. 13 to 17 are shown in FIGS. 6 to 12 except that the short-circuit cavity surface 25 is not provided. It is assumed that the dimensions are the same as those of the fixed mold 20 and the movable mold 30 in the present invention. The label 10 in a tubular shape wound by the label supply unit 80 is set on the fixed mold 20 in the open mold state as shown in FIG. Next, when the movable mold 30 is advanced by the mold clamping device 60, the fixed mold 20 and the movable mold 30 are in the mold closed state as shown in FIG.

FIG. 8 is an enlarged cross-sectional view of the portion of the box A'in FIG. FIG. 8 shows a state at the time when the fixed mold 20 and the movable mold 30 are closed and before the cavity C is filled with the molten resin. In the present embodiment, the length of the label 10 protruding from the flange back cavity surface 23 of the fixed mold 20 toward the movable mold 30 is set to L1. This length L1 is the same as the length L1 shown in FIG. 14 that protrudes from the flange back cavity surface 123 of the label 110 set in the conventional fixed mold 120 toward the movable mold 130 side. In other words, the protruding length L1 of the label 10 is set to the length up to the flange surface cavity surface 33 of the movable mold 30 at the time of mold closing. Therefore, in the molded container 1, the range in which the label 10 covers the flange 4 is different from the range illustrated in the enlarged cross section of FIG. Reference numeral L3 in FIG. 8 is the cross-sectional length of the label end portion 10b. The length L1 is a part of the length L3. Reference numeral L4 in FIG. 8 is the cross-sectional length of the short-circuit cavity surface 25. In the present embodiment, the length L3 of the label end portion 10b is larger than the cross-sectional length L4 of the short-circuit cavity surface 25 (L3> L4).

FIG. 9 is a partially enlarged cross-sectional view showing a state in which the cavity C is filled with the molten resin from the state of FIG. The molten resin is filled into the cavity C from the nozzle 45 of the cylinder 41 of the injection device 40 via the passage 20b of the fixed mold 20. The resin flowing from the peripheral wall cavity portion C3 into the flange cavity portion C4 bends the label end portion 10b of the label 10 toward the short-circuit cavity surface 25 on the outer side in the radial direction, and follows the short-circuit cavity surface 25 and the flange back cavity surface 23. Arranged as. In FIG. 9, the virtual extension surface 22'is a surface obtained by extending the peripheral wall outer cavity surface 22 toward the flange cavity portion C4 side when it is assumed that there is no short-circuit cavity surface 25. The virtual extension surface 23'is a surface obtained by extending the flange back cavity surface 23 toward the peripheral wall cavity portion C3 side when it is assumed that there is no short-circuit cavity surface 25. Further, the connection portion between the peripheral wall outer cavity surface 22 and the short-circuit cavity surface 25 is 22a, and the connection portion between the short-circuit cavity surface 25 and the flange back cavity surface 23 is 22b. The length from the connecting portion 22a to the connecting portion 22b via the short-circuit cavity surface 25 is shorter than the length from the connecting portion 22a to the connecting portion 22b via the virtual extension surface 22'and the virtual extension surface 23'. Therefore, the position of the end 10e of the label 10 is radially outside the position of the end 10e of the label 10 assuming that there is no short-circuit cavity surface 25. Therefore, since the container 1 in this example is provided with the short-circuit cavity surface 25, the label 10 is provided with the short-circuit cavity surface so as to reach the flange back cavity surface 23 from the peripheral wall outer cavity surface 22 through the short-circuit cavity surface 25. It can be short-circuited at 25. As described above, in the mold 200 according to the present invention, the label 10 can be short-circuited to the flange back cavity surface 23 via the short-circuit cavity surface 25. Therefore, even if the protrusion lengths L1 from the flange back cavity surfaces 23 and 123 of the labels 10 and 110 are the same, as shown in FIGS. 9 and 15, the mold 200 of the present invention uses the conventional mold. By comparison, the flange 4 of the container 1 can be covered more widely with the label 10 outward in the radial direction. Since L3> L4 as described above, the label end portion 10b is arranged over the entire area of the short-circuit cavity surface 25 and further along a part of the flange back cavity surface 23. As described above, in the mold 200 according to the present invention, the label 10 can be short-circuited to the flange back cavity surface 23 via the short-circuit cavity surface 25. Therefore, even if the protrusion lengths L1 from the flange back cavity surfaces 23 and 123 of the labels 10 and 110 are the same, as shown in FIGS. 9 and 15, the mold 200 of the present invention uses the conventional mold. By comparison, the flange 4 of the container 1 can be covered more widely with the label 10 outward in the radial direction. As described above, the in-mold label container 1 in which the in-mold label 10 is integrated on the peripheral wall 3 is molded. In the container 1, the portion corresponding to the short-circuit cavity surface 25 appears as a thick portion 5.

Next, an embodiment in which the protrusion length of the label 10 is longer than that of L1 as compared with the embodiment based on FIGS. 7 and 8 described above will be described with reference to FIGS. 10 to 12. FIG. 10 is a partially enlarged cross-sectional view showing a state immediately before the fixed mold 20 and the movable mold 30 are closed. In the present embodiment, the length of the label 10 protruding from the flange back cavity surface 23 of the fixed mold 20 toward the movable mold 30 is set to L1'. The length L1'is the same as the length L1'shown in FIG. 16 protruding from the flange back cavity surface 123 of the label 110 set on the conventional fixed mold 120 toward the movable mold 130. L1'is longer than L1 described above. The protruding length L1'is longer than the length L2 along the radial direction of the flange back cavity surface 123 of the conventional fixed type 120. Immediately before closing the mold in FIG. 10, the end of the label 10 on the movable mold 30 side is in contact with the flange front cavity surface 33 of the movable mold 30. At this point, there is a slight clearance between the movable type 30 side end surface 26 of the fixed type 20 and the front end surface 35 of the movable type 30 stripper 30B. FIG. 11 is a partially enlarged cross-sectional view showing a time point when the fixed mold 20 and the movable mold 30 are closed. The time point in FIG. 11 is before the cavity C is filled with the molten resin. As the movable mold 30 moves from the time point of FIG. 10 to the time of mold closing of FIG. 11, the flange front cavity surface 33 of the movable mold 30 pushes the movable mold 30 side end of the label 10 forward. As a result, the label end portion 10b of the label 10 is bent from the end 22a of the peripheral wall outer cavity surface 22 on the flange back cavity surface 23 side. At this time, the label end portion 10b is in a form of being released to the space on the short-circuit cavity surface 25 side, which is the side originally slightly tilted. In the conventional mold, when the protruding length of the label 110 is L1', the label 110 buckles as shown in FIG. On the other hand, in the mold 200 of the present invention, the label 10 does not buckle even when the protruding length of the label 10 is the same L1'.

FIG. 12 is a partially enlarged cross-sectional view showing a state in which the cavity C is filled with the molten resin from the state of FIG. When the molten resin is filled in the peripheral wall cavity portion C3 and the flange cavity portion C4 from the state of FIG. 11, as shown in FIG. 12, the label end portion 10b of the label 10 has a short-circuit cavity surface 25, a flange back cavity surface 23, and a flange. Arranged along the end cavity surface 24. This makes it possible to cover the flange 4 of the container 1 wider than before. In the present embodiment, the label 10 covers about half of the end face 4c of the flange 4, but may or may not cover the entire or most of the end face 4c, or may not cover the end face 4c. Through the above steps, the in-mold label container 1 is molded.

From the above, in the in-mold label container molding mold 200 according to the present invention, the label 10 can be short-circuited from the peripheral wall outer cavity surface 22 to the flange back cavity surface 23 by the short-circuit cavity surface 25. Therefore, the label 10 makes it possible to cover the flange 4 of the container 1 more widely, and the oxygen barrier property of the container 1 can be enhanced. Further, the height of the label 10 set on the fixed mold 20 toward the movable mold 30 can be set high, which also makes it possible to cover the flange 4 of the container 1 more widely.

The method for molding the in-mold label container using the mold according to the present invention is as follows.
An in-mold label container including a bottom wall, a peripheral wall, a flange protruding from an end opposite to the bottom wall in the axial direction of the peripheral wall toward the outer peripheral side, and an in-mold label integrated with the outer peripheral surface of the peripheral wall. To make a mold for injection molding,
The mold includes a first mold having a first cavity surface and a second mold having a second cavity surface, and the in-mold label container is placed between the first cavity surface and the second cavity surface. A cavity for molding is formed,
The first cavity surface of the first type includes a peripheral wall outer cavity surface corresponding to the outer surface of the peripheral wall, a flange back cavity surface corresponding to the bottom wall side surface of the flange, and the peripheral wall outer cavity surface. Including a short-circuit cavity surface provided between the flange back cavity surface and the flange back cavity surface.
The second cavity surface of the second type includes a flange surface cavity surface corresponding to a surface of the flange opposite to the bottom wall.
The short-circuit cavity surface is a method of molding an in-mold label container using a mold configured so that the thickness of the peripheral wall cavity portion is gradually increased toward the flange back cavity surface.
A step of setting a tubular label on the outer cavity surface of the first mold in the mold-opened state, and a step of projecting a part of the label from the flange back cavity surface toward the movable mold side.
This includes a step of filling the cavity with resin and arranging the label from the peripheral wall outer cavity surface of the first type to the flange back cavity surface via the short-circuit cavity surface.

1 In-mold label container 2 Bottom wall 3 Peripheral wall 3a Peripheral wall outer peripheral surface 4 Flange 4a Flange back surface 4c Flange end surface 5 Thick part 10 In-mold label 10b Label flange back cavity surface side (label end)
20 Fixed type (1st type)
20a Fixed cavity surface (first cavity surface)
22 Outer wall cavity surface 22a Right end of outer peripheral cavity surface 23 Flange back cavity surface 25 Short-circuit cavity surface 30 Movable type (2nd type)
30a Movable cavity surface (second cavity surface)
30A Core 30B Stripper 40 Injection device 50 Moving device 60 Mold clamping device 61 Fixed platen 62 Movable platen 70 Ejector device 80 Label supply unit 90 Label extraction unit 100 Injection molding machine 200 In-mold label container Molding mold 201 In-mold label container injection Molding System 202 In-Mold Label Container Molding System C Cavity C3 Peripheral Wall Cavity C4 Flange Cavity

Claims (6)

An in-mold label container including a bottom wall, a peripheral wall, a flange protruding from an end opposite to the bottom wall in the axial direction of the peripheral wall toward the outer peripheral side, and an in-mold label integrated with the outer peripheral surface of the peripheral wall. Is a mold for injection molding
The mold includes a first mold having a first cavity surface and a second mold having a second cavity surface, and the in-mold label container is placed between the first cavity surface and the second cavity surface. A cavity for molding is formed,
The first cavity surface of the first type includes a peripheral wall outer cavity surface corresponding to the outer peripheral surface of the peripheral wall, a flange back cavity surface corresponding to the bottom wall side surface of the flange, and the peripheral wall outer cavity surface. Including a short-circuit cavity surface provided between the flange back cavity surface and the flange back cavity surface.
The short-circuit cavity surface is an in-mold label container molding die characterized in that the thickness of the peripheral wall cavity portion corresponding to the peripheral wall in the cavity is gradually increased toward the flange back cavity surface. The mold for molding an in-mold label container according to claim 1, wherein the short-circuit cavity surface has a straight cross section along the axis of the outer peripheral cavity surface and a curved shape having a convex shape on the inner peripheral side. An in-mold label container including a bottom wall, a peripheral wall, a flange protruding from an end opposite to the bottom wall in the axial direction of the peripheral wall toward the outer peripheral side, and an in-mold label integrated with the outer peripheral surface of the peripheral wall. And
An in-mold label characterized by providing a thick portion for gradually increasing the thickness of the peripheral wall toward the flange between the outer peripheral surface of the peripheral wall and the surface of the flange on the bottom wall side in the axial direction. container. The in-mold label is arranged from the outer peripheral surface of the peripheral wall to the back surface of the flange via the outer peripheral surface of the thick portion.
3. The third aspect of the present invention is that the end of the in-mold label on the flange side is arranged on the outer peripheral side of the flange rather than the end of the in-mold label on the flange side when there is no thick portion. In-mold label container described in. The in-mold label container according to claim 3 or 4, wherein the in-mold label covers the entire back surface of the flange. The in-mold label container according to any one of claims 3 to 5, wherein the outer peripheral surface of the thick portion has a straight cross section along the axis of the peripheral wall or a curved shape having a concave shape on the inner peripheral side.

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