JP2015193406A - Package and heat-shrinkable film for lid used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package capable of ensuring easy opening and a heat-shrinkable film for a lid used for the same.SOLUTION: In a package where the opening 10 of a container 1 is covered with a heat-shrinkable film 2 for a lid, the heat-shrinkable film 2 for the lid is equipped with a knob part 22. The heat-shrinkable film 2 for the lid is composed of a highly stretching film to a uniaxial side. The knob parts 22 are provided respectively at both ends of the heat-shrinkable film 2 for the lid perpendicular to a highly stretching direction in the heat-shrinkable film 2 for the lid. A rear suppression part where a shrinkage suppression layer is formed only on the rear surface of the knob part 22 is disposed. The knob part 22 is curled to a surface side so as to be separated from the side surface part 12 of the container 1 to outside.

Description

  The present invention relates to a package in which an opening of a container is covered with a heat-shrinkable film for a lid, and a heat-shrinkable film for a lid used in the package.

  Conventionally, a heat shrinkable film for a lid as a film lid for covering an opening of a container is known, for example, as described in Patent Document 1 below. The heat-shrinkable film for the lid has a larger area than the opening of the container, and the portion that protrudes outward from the opening edge of the container is thermally contracted to be attached to the container, and the closed state is maintained. The However, it is not easy to pick the outer edge portion of the heat-shrinkable film for lids, and therefore there is a problem that the opening operation is difficult.

Japanese Patent Laid-Open No. 51-116788

  Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a package that can be easily opened and a heat-shrinkable film for a lid used therefor.

  The present invention has been made to solve the above problems, and the package according to the present invention is a package in which an opening of a container is covered with a heat-shrinkable film for a lid, and the heat-shrink for a lid. The conductive film includes a uniaxial high-stretch film, and includes a top surface portion that covers the opening of the container, and a skirt portion that extends downward from the top surface portion. The heat-shrinkable film for the lid is provided on the skirt portion. Of the two end portions in the direction perpendicular to the high-stretching direction, at least one end portion is provided with a knob portion spaced outward from the side surface portion of the container. The direction orthogonal to the high-stretching direction does not mean a strictly 90 degree angle with respect to the high-stretching direction, but is preferably within 90 ° ± 8 °, more preferably 90 ° ± 5. Means within degrees.

  In the package having such a structure, since the heat shrinkable film for the lid is composed of a uniaxial high-stretch film, when the opening of the container is capped with the heat shrinkable film for the lid, the opening edge of the container When the peripheral region of the heat-shrinkable film for lids protruding outward from the film is heat-shrinked, the shrinkage amount in the direction perpendicular to the high-stretching direction is relatively small while shrinking greatly in the high-stretching direction. Therefore, the end in the direction orthogonal to the high-stretching direction is likely to remain in a state of extending a pinch shape (tongue piece shape) relatively longer than other portions, and the end in the direction orthogonal to the high-stretching direction. The part can be easily configured as a knob. And it can be easily opened by picking the knob.

  Furthermore, it is preferable that the knob portion is provided with a back suppression portion in which a shrinkage suppression layer is formed only on the back surface. According to this configuration, the shrinkage amount on the front surface side is larger than that on the back surface side in the back suppression portion, and the knob is curled so as to warp back to the front surface side due to heat shrinkage. Therefore, the knob is easily separated from the side surface of the container, and the knob curled on the surface side can be picked and easily opened. Moreover, since the excessive shrinkage | contraction is suppressed by providing a back suppression part, a beautiful pick part is formed.

  Furthermore, it is preferable that the skirt portion is provided with a front suppressing portion in which a shrinkage suppressing layer is formed only on the surface. According to this configuration, since the shrinkage amount on the back surface side is larger than the front surface side in the front restraining portion, the peripheral region of the heat shrinkable film for lids that protrudes outward from the opening edge portion of the container smoothly during heat shrinkage. A beautiful skirt is formed by curling on the back side, and the holding force to the container is also increased, so that the closed state is more reliably held.

  Still further, in the skirt portion, it is preferable that the front suppressing portion is provided between a boundary with the top surface portion and an inner edge of the back suppressing portion. According to this configuration, the skirt portion contracts toward the inner container by the front restraint portion located between the boundary with the top surface portion and the inner edge of the back restraint portion, while the knob portion is surfaced by the back restraint portion. Since it curls to the side and warps away from the container, the knob can be easily picked and opened, maintaining the ease of opening, and achieving both the sealing function and the ease of opening.

  Further, it is preferable that a weakening line extending a predetermined length inward from the outer edge of the lid heat-shrinkable film is formed in the vicinity of the knob. According to this structure, when the knob is picked and lifted at the time of opening, the heat-shrinkable film for lids is cut from the outer edge toward the inside along the weakening line, so that the opening can be further facilitated.

  Moreover, the heat-shrinkable film for lids according to the present invention is used for such a package.

  As described above, the ease of opening is ensured by the knob of the heat-shrinkable film for lids.

The perspective view which shows the package in one Embodiment of this invention. The front view which looked at the packaging body in the high extending direction of the heat-shrinkable film for lids. The figure which looked at the heat-shrinkable film for lids used for the package from the surface side. The figure which looked at the heat-shrinkable film for lids from the back side. AA sectional drawing of FIG. The front view which shows the state in the middle of manufacture of the package body. The principal part front view which shows the state in the middle of opening of the package. Sectional drawing of the heat-shrinkable film for lid | cover in other embodiment of this invention.

  Hereinafter, the heat-shrinkable film for lids according to an embodiment of the present invention and a package on which the film is mounted will be described with reference to FIGS. The package shown in FIG. 1 contains various contents in a cup-shaped container 1 having a bottomed cylindrical shape with an upper opening, and the opening 10 of the container 1 is covered with a heat shrinkable film 2 for a lid. The lid is closed. The contents are not particularly limited, but the contents are preferably individually packaged in a packaging bag. When the contents are individually packaged, the contents do not leak out of the package, even if the sealing property of the closed state by the lid heat-shrinkable film 2 is not so high.

  The cross-sectional shape (cross-section cut in the horizontal direction) and the opening shape of the container 1 may be arbitrary and may be a square shape or the like, but in this embodiment, it has a circular cross-sectional shape and a circular opening shape. . Accordingly, the container 1 has a configuration including a circular bottom surface portion 11 and a cylindrical side surface portion 12 that rises upward from the periphery of the bottom surface portion 11 and rises upward. The flange portion 13 protrudes outward from the opening edge over the entire circumference. The outer edge of the opening edge of the container 1 becomes the outer edge 13 a of the flange portion 13. The container 1 is made of, for example, a synthetic resin or a paper material. In the case of synthetic resin, it is formed by injection molding or sheet molding. In the case of paper, for example, the side surface portion 12 and the bottom surface portion 11 can be separately formed and joined and integrated, and the left and right ends of one sheet are overlapped to form a cylindrical shape. In addition, the container 1 can be formed by joining the circular bottom surface portion 11 to the lower end of the side surface portion 12.

  The heat-shrinkable film 2 for the lid includes a flat and circular top surface portion 20 that covers the opening 10 of the container 1 and a ring-shaped skirt that extends downward from the periphery of the top surface portion 20 when mounted on the container 1. Part 21. The top surface portion 20 faces the upper surface of the flange portion 13 at the peripheral edge thereof, and the skirt portion 21 extends downward so as to cover the outer side of the flange portion 13 and wraps inwardly below the flange portion 13 so as to wrap around the side surface portion 12. Abuts on and covers the upper outer peripheral surface of the plate. The vertical length of the skirt portion 21 extending downward from the top surface portion 20 is not constant over the entire circumference, and is relatively long at two positions facing each other by 180 degrees, and two positions facing each other by 180 degrees perpendicular to the two positions. And the length gradually changes between a relatively long portion and a relatively short portion.

  And the two places extended in the shape of a knob | pick (tongue piece shape) longer than the other part among the perimeters of the outer edge part of the skirt part 21 leave | separate outward from the side part 12 of the container 1, respectively. Thus, the knob 22 is curled on the surface side. The knob portion 22 is provided with a back suppression portion in which a shrinkage suppression layer is formed only on the back surface. Details of the back suppression portion will be described later. In FIG. 1, cross-hatching is applied to the location of the back suppression portion, and the same applies to FIG. Moreover, the heat shrinkable film 2 for lid | covers is comprised from the film highly stretched to the uniaxial side so that it may mention later, and two places where the up-down direction length of the skirt part 21 is relatively long are for lid | covers. Two locations where both ends of the heat-shrinkable film 2 are orthogonal to the high-stretching direction and the skirt portion 21 has a relatively short vertical length are the heights of the heat-shrinkable film 2 for the lid. It is the both ends of a extending direction. In FIG. 1, the direction of arrow X is the high stretching direction, and in FIG. 2, the direction of arrow Y is the direction orthogonal to the high stretching direction. A pair of left and right weakening lines 38 extending a predetermined length inward from the outer edge of the lid heat-shrinkable film 2 are formed in the vicinity of the knob portion 22.

  A specific configuration of the lid heat-shrinkable film 2 will be described in a state before being attached to the container 1, that is, a state before heat-shrinking. 3 to 5 show the heat-shrinkable film 2 for the lid before heat shrinkage, FIG. 3 is a view seen from the front side, FIG. 4 is a view seen from the back side, and FIG. It is AA sectional drawing.

  The lid heat-shrinkable film 2 is circular before heat shrinkage, and this corresponds to the shape of the opening 10 of the container 1. 3 and 4, the outer edge 13 a of the flange portion 13 of the container 1 is indicated by a two-dot chain line. However, for the lid before thermal contraction, a predetermined amount protrudes outside the outer edge 13 a of the flange portion 13 of the container 1. The heat-shrinkable film 2 has a larger diameter than the outer edge 13a of the flange portion 13. 3 and 4, the annular region outside the two-dot chain line is a region that protrudes outside the flange portion 13 of the container 1 when the heat shrinkable film 2 for lids is placed on the upper surface of the container 1. This region will be referred to as the peripheral region 30. Thus, in the state before shrinkage | contraction, the heat-shrinkable film 2 for lid | covers is provided with the circular center area | region and the annular peripheral area | region 30 of the outer side.

  As shown in FIG. 5, the heat-shrinkable film 2 for the lid is laminated on the base film 31, the front printing layer 32 laminated on the surface of the base film 31, and the back surface of the base film 31. Back printed layer. The back print layer is composed of a first back print layer 35 and a second back print layer 36. And both the front printing layer 32 and the 1st back printing layer 35 comprise a shrinkage | contraction suppression layer from exhibiting the function which suppresses the heat shrink of the base film 31. FIG.

  The base film 31 is a so-called shrink film, and is made of a uniaxial high-stretch film. In the case of so-called front printing in which display layers of various designs and characters are formed on the front surface, the base film 31 may be opaque, but the display layer is formed on the back surface to form the base film 31. In the case of a configuration in which the display layer on the back side is viewed through, so-called back printing, a transparent base film 31 is used. Here, the uniaxially-highly stretched film is a film in which one axial direction is stretched more than the other axial direction, and a film having different thermal shrinkage rates in the so-called MD direction and the so-called TD direction. This does not mean only a film that does not shrink at all in any direction (so-called thermal shrinkage is zero). The uniaxially highly stretched film may be transverse uniaxial stretching in which the TD direction is more stretched than the MD direction, or may be longitudinal uniaxial stretching in which the MD direction is more stretched than the TD direction. The difference between the thermal shrinkage rate in the TD direction and the thermal shrinkage rate in the MD direction in the uniaxially highly stretched film is usually 40% or more, and preferably 50% or more. Among them, the thermal shrinkage rate (the thermal shrinkage rate in the MD direction in the case of lateral uniaxial stretching) having a smaller thermal shrinkage rate among the thermal shrinkage rate in the TD direction and the thermal shrinkage rate in the MD direction is 10% or less. Those are more preferred.

  3 and 4, the direction indicated by the arrow X is the high stretching direction, the direction indicated by the arrow Y is the direction orthogonal to the high stretching direction, and the uniaxial side highly stretched film has the TD direction in the MD direction. In the case of a laterally uniaxially stretched film that is more stretched compared to, the direction indicated by arrow X is the TD direction, and the direction indicated by arrow Y is the MD direction. In addition, the high extending | stretching direction of a uniaxial side highly stretched film is a direction extended | stretched more among TD direction and MD direction.

  Examples of the uniaxial high-stretch film include, for example, linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), polyolefins such as polypropylene (PP), polyethylene terephthalate (PET), poly Polyesters such as butylene terephthalate (PBT), polystyrenes (PS), polylactic acid (PLA), polyamides, ethylene vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), polychlorinated The film which consists of vinyl-type resin, such as vinyl, is mentioned. Moreover, the film containing the resin mixture which mixed 2 or more types of these resin can also be used, and the laminated | multilayer film which laminated | stacked 2 or more types of films can also be used. Of these, polyester-based, polyolefin-based, and polystyrene-based films are preferable because they have appropriate shrinkage stress and high transparency, and polyester-based films and polystyrene-based films are particularly preferable. Although the thickness of a uniaxial side highly stretched film is not specifically limited, It is preferable that it is 8-100 micrometers, More preferably, it is 10-80 micrometers, Especially preferably, it is 15-60 micrometers.

  The front print layer 32 is shown with a large number of dots in FIG. The front printed layer 32 is formed on the entire surface of the base film 31 except for both ends in a direction orthogonal to the high stretching direction. Accordingly, the front-side unprinted areas 33 where the front printed layer 32 is not formed are present at both ends in the direction orthogonal to the high-stretching direction, and each of the front-side unprinted areas 33 is the peripheral area 30. Is in. The boundary line 34 between the unprinted region 33 on the front side and the front printed layer 32 is a straight line along the high-stretching direction in the present embodiment, but may be a curved line or the like. Moreover, it is preferable that the dimension of the high extending direction of the unprinted area 33 on the front side is longer than the dimension of the direction orthogonal to the high extending direction. The surface printing layer 32 can be, for example, a clear varnish layer, and for example, a UV curable varnish can be used. The front printing layer 32 can be formed by various known printing methods such as gravure printing, and the back printing layer described later is also the same.

  The back printed layer includes a first back printed layer 35 formed at both ends in a direction orthogonal to the high stretching direction, and a first back printed layer 35 spaced inward from the first back printed layer 35. Comprises a second back printed layer 36 formed independently. In FIG. 4, the first back printed layer 35 and the second back printed layer 36 are provided with a large number of dots. The first back printed layer 35 has a front-back correspondence relationship with the unprinted area 33 on the front side, and is formed in the same area on the back side of the unprinted area 33 on the front side with the same area. However, the first back printed layer 35 may not have the same area as the unprinted area 33 on the front side.

  The second back printed layer 36 is formed on the inner side (center side) than the peripheral region 30. The second back printed layer 36 may be the entire region inside the peripheral region 30 (that is, the entire region inside the two-dot chain line in FIG. 4), or is formed so as to partially protrude from the peripheral region 30. However, it is preferable that the entirety is located inside the peripheral region 30. The size and shape of the second back printed layer 36 are arbitrary and are not limited to regular hexagons as in the present embodiment. The second back printed layer 36 is a display of a product name or a design showing the contents, and the packaging body is displayed at the lower stage of the display shelf by using the transparent base film 31 as described above. Even if it is a case, it is easily visible from above. An acrylic ink is preferably used for the first back printing layer 35 and the second back printing layer 36, but various inks such as a urethane type can be used. The ink may or may not contain a pigment, and may be a UV curable ink.

  Thus, since the first back printed layer 35 and the second back printed layer 36 are formed on the back surface of the base film 31 so as to be separated from each other, the first back printed layer 35 and the second back printed layer 36 are separated from each other. An unprinted area 37 on the back side that is not printed exists between the print layer 36. The second back printed layer 36 is located inside the peripheral region 30. Therefore, the entire back surface of the peripheral region 30 becomes the unprinted region 37 on the back side except for the first back printed layer 35. That is, most of the back surface of the peripheral region 30 becomes the unprinted region 37 on the back side, and the unprinted region 37 on the back side exists over the entire periphery of the peripheral region 30.

  In this embodiment, the back suppression portion in which the shrinkage suppression layer is formed only on the back surface is a portion where the front surface is the unprinted area 33 on the front side and the first back print layer 35 is formed on the back surface. When this part is attached to the container 1 by heat shrinkage, it becomes a knob 22. As shown in the present embodiment, the inner side edge of the back restraining portion is such that the unprinted area 33 on the front side and the first back printed layer 35 are in a front-to-back correspondence relationship. When the boundary line 34 between them and the boundary line 39 between the first back printed layer 35 and the unprinted area 37 on the back side coincide with each other, these boundary lines 34 and 39 are the back suppression portions. It becomes the inner edge of. However, the front-side boundary line 34 and the back-side boundary line 39 may be different from each other. For example, when the front-side boundary line 34 is positioned inside the back-side boundary line 39, the back-side boundary line 34 39 is the inner edge of the back restraining portion, and conversely, when the rear boundary line 39 is located inside the front border 34, the front border 34 is the inner edge of the back restraining portion. . Further, in the present embodiment, the front suppressing portion in which the shrinkage suppressing layer is formed only on the front surface is a portion in which the front printed layer 32 is formed on the front surface and the back surface is the unprinted region 37 on the back side. Therefore, in the present embodiment, most of the peripheral region 30 is a front suppressing portion. And the table | surface suppression part exists over the perimeter of the peripheral area | region 30. FIG.

  Further, as shown in FIGS. 3 and 4, a pair of weakening lines 38 is provided in the vicinity of the front-side unprinted region 33 (first back print layer 35) at both ends in the direction orthogonal to the high-stretching direction. Is formed. The weakening line 38 may have various configurations, but may be a perforation, for example. The weakening line 38 extends inward from the outer edge of the heat shrinkable film 2 for lids. Specifically, the heat shrinkable film for lids is located at a predetermined distance inside the unprinted area 33 on the front side. A predetermined length is formed on the inner side from the outer edge of 2 along the direction of high stretching. In the present embodiment, the boundary line 34 between the unprinted area 33 on the front side and the front printed layer 32 is a straight line, but a weak line 38 is formed in parallel with the boundary line 34. The left and right weakening lines 38 are symmetrically located on the same line, but the inner ends of the left and right weakening lines 38 are separated from each other. The weakening line 38 is formed in the peripheral region 30.

  When the cover heat-shrinkable film 2 configured as described above is placed on the upper surface of the container 1 (the upper surface of the flange portion 13), the peripheral region 30 protrudes outward from the flange portion 13 of the container 1 as shown in FIG. It becomes a state. In this state, the region (center region) inside the peripheral region 30 is pressed from above so as to be covered with a pressing member (not shown) so that the region is not thermally contracted. The peripheral region 30 is thermally contracted. Since the peripheral region 30 is provided with a front suppressing portion, the peripheral region 30 is flanged while curling so as to bend downward as indicated by an arrow α as a result of suppressing thermal shrinkage on the front side by the front printed layer 32. It wraps around the lower side of the part 13, approaches the side part 12 of the inner container 1, and comes into contact with the upper outer peripheral surface of the side part 12. And when the table | surface suppression part is provided over the perimeter of the peripheral area | region 30, the peripheral area | region 30 will contact | abut to the upper outer peripheral surface of the side part 12 over the perimeter. Thus, the above-mentioned skirt part 21 is comprised by the thermal contraction of the peripheral area | region 30. FIG. A circular central region inside the peripheral region 30 is the top surface portion 20.

  Furthermore, since the heat-shrinkable film 2 for lids is composed of a film that is highly stretched uniaxially, it shrinks greatly in the high-stretching direction, but the shrinkage amount in the direction perpendicular to the high-stretching direction is small. Therefore, the peripheral region 30 is greatly contracted in the high stretching direction, but is not so contracted in the direction orthogonal to the high stretching direction, and the contraction amount is small. As a result, in the entire circumference of the peripheral region 30, both ends in the direction orthogonal to the high stretching direction remain in a relatively long state, and both ends in the high stretching direction become relatively short. Accordingly, both end portions in the direction orthogonal to the high-stretching direction, which is a portion having a relatively long hang from the top surface portion 20, become the grip portion 22 in a state that is relatively easy to pick compared to other portions.

  Moreover, since the back suppression part is each provided in the both ends of the direction orthogonal to a high extending | stretching direction, in the back suppression part among the peripheral regions 30, the thermal contraction of a back side is suppressed by the 1st back printed layer 35. Thus, the container 1 is curled away from the side surface 12 of the container 1. In this way, when the back restraining part is biased toward the surface side and thermally contracts, a knob part 22 that is curled so as to be separated from the side surface part 12 of the container 1 and curled back to the surface side is formed. Further, the weak line 38 that was linear along the high-stretching direction as shown in FIGS. 3 and 4 before the heat shrinkage is inclined in a direction perpendicular to the high-stretching direction after the heat shrinkage as shown in FIG. It will be in the state. That is, the weak line 38 is extended toward the center of the lid heat-shrinkable film 2 after the heat shrinkage.

  In the heat-shrinkable film for lids configured as described above, since the front suppressing portion is provided over the entire circumference in the peripheral region 30, it is smoothly directed toward the side surface portion 12 of the container 1 at the time of heat-shrinking. As a result, a good aesthetics can be obtained, and the mounting state of the heat-shrinkable film 2 for lids on the container 1 is ensured, and a reliable sealing function is exhibited. In particular, since the flange portion 13 is formed on the container 1, a high holding force can be easily obtained, and the skirt portion 21 surely surrounds the lower side of the flange portion 13 by providing the front suppressing portion. As a result, more reliable sealing characteristics can be obtained, and the sealing performance can be improved. Furthermore, if the front surface suppressing portion is provided in the peripheral region 30, the peripheral region 30 automatically curls to the back side by heating, so that the peripheral region 30 is pushed by a member from the top and directed downward, for example. Even when a mechanical and forced bending facility is not required or when these facilities are used, the peripheral region 30 can be more easily and smoothly arranged on the side surface of the container 1. 12 can be heat shrunk toward 12.

  And since the heat shrinkable film 2 for lid | covers is comprised from the film highly stretched to the uniaxial side, in the skirt part 21, the edge part of the direction orthogonal to a high stretch direction is relative compared with another part. Therefore, since it is in a state of being long and remaining in a knob shape, a knob portion 22 protruding from the outer edge portion is formed, and the knob portion 22 can be easily picked and opened easily. Therefore, it is not necessary to form a knob that protrudes radially outward in the state before heat shrinkage, or even if a knob is temporarily formed, only a small protrusion is required. When the heat-shrinkable film 2 for a lid is punched out from a length film, the waste of the film is reduced and high productivity is secured. Furthermore, since it is comprised from the uniaxial side highly stretched film, the edge part of the direction orthogonal to the high extending | stretching direction which is the state extended long in the pick shape does not become hard too much, and when picking the pick part 22 There is also an advantage that it is excellent in touch. Moreover, since the knob 22 is curled to the surface side by the back restraining part and separated from the side surface 12 of the container 1, the knob 22 can be easily picked and opened.

  Further, since the weakening lines 38 are formed in the vicinity of the left and right sides of the knob 22, for example, when a right-handed person picks the knob 22 with the right hand and opens it, as shown in FIG. 7. The lid 22 can be easily opened by cutting the lid heat-shrinkable film 2 along the weakening line 38 on the left side when the knob 22 is viewed in front. When a left-handed person picks the knob 22 with his left hand and opens it, the lid 22 is cut along the weakening line 38 on the right side when the knob 22 is viewed from the front. Can be opened. Since the heat shrinkable film 2 for the lid is not bonded to the flange portion 13 or the like of the container 1, it is easy to remove a predetermined portion of the entire circumference of the heat shrinkable film 2 for the lid from the flange portion 13. The container 1 can be removed. In this way, if a pair of weakening lines 38 is formed on the left and right sides, it can be easily opened with either the right or left hand.

  Samples of the heat-shrinkable film 2 for the lid are prepared from the various films shown in Table 1, and each is attached to the container 1 to evaluate whether or not the knob 22 is formed. It was evaluated whether or not can be cut reliably. The evaluation results are shown in Table 2. A perforation was formed as the weakening line 38.

The measurement of the heat shrinkage rate was performed as follows. As a measurement sample, a rectangular sample having a length of 200 mm (mark interval 150 mm) and a width of 10 mm was cut out and prepared. The sample was heat-treated in warm water at 100 ° C. for 10 seconds (no load), and a sample before and after the heat treatment was obtained. The difference in line spacing was read, and the heat shrinkage rate was calculated by the following formula.
Thermal contraction rate (%) = (L0−L1) / L0 × 100
L0: Mark interval before heat treatment L1: Mark interval after heat treatment

  The average tear strength of the film was measured according to the JIS K 7128 A method. The greater the average tear strength, the greater the force required to cut the film along the perforation, and the easier it is to crack the film away from the perforation in the middle of the perforation, The smaller the average tear strength, the more the film can be cut along the perforation with a smaller force.

  Regarding the evaluation of whether or not the knob portion 22 is formed, in a state before heat shrinkage, a circular shape in which a knob piece is not projected in advance on the outer edge of the heat shrinkable film 2 for lid, and before heat shrinkage. In the state, it evaluated about both what protruded the protruding piece in the outer edge of the heat-shrinkable film 2 for lid | covers. Furthermore, it evaluated also about the case where a back suppression part is provided in the edge part of the direction orthogonal to an extending | stretching direction (with a back suppression part), and the case where it does not provide (no back suppression part). And the case where the knob | pick part 22 was formed was set to (circle), and the case where it was not formed was set to x.

  “Perforation evaluation” was evaluated based on whether or not the film was cracked so as to be detached from the perforation while the film was being cut along the perforation. ○ when the film is cut to the end of the perforation along the perforation, and × when the film is not cut to the end along the perforation and deviates from the perforation in the middle did.

  As can be seen from the evaluation results in Table 2, when the heat-shrinkable film 2 for a lid is circular and the back suppressing portion is not provided at the end in the direction orthogonal to the high-stretching direction, the sample No. 1-No. 4, the knob 22 is formed. 5 and sample no. In No. 6, the pick part 22 was not formed. Therefore, the difference between the thermal contraction rate in the TD direction and the thermal contraction rate in the MD direction (TD-MD in Table 1) is preferably 50% or more, and further, the thermal contraction rate in the MD direction is 10%. It can be seen that it is preferable to be not more than%.

  Further, even if the heat shrinkable film 2 for the lid is circular, if a back suppressing portion is provided at the end in the direction orthogonal to the high stretching direction, the sample No. 5, it was found that the knob 22 was formed. From this, even if the difference between the thermal shrinkage rate in the TD direction and the thermal shrinkage rate in the MD direction is less than 50% by providing a back suppression portion at the end in the direction orthogonal to the high stretching direction, It was found that there is a part where the knob 22 is formed, and the allowable range regarding the directionality of the heat shrinkage rate of the film is expanded. In addition, if a knob is provided in advance at a predetermined position on the outer edge in the state before heat shrinkage, the sample No. The knobs 22 were formed for all the samples including 6. Therefore, in the case of a film in which the difference between the thermal shrinkage rate in the TD direction and the thermal shrinkage rate in the MD direction is less than 50%, a back suppression portion is provided in the portion that becomes the knob portion 22 after the thermal shrinkage, It is advisable to project a knob in advance. Sample No. When the table restraining portion is provided over the entire circumference of the two peripheral regions 30, the side region 12 of the container 1 can be surely and smoothly connected to the peripheral region 30 with simpler equipment than in the case where the table restraining portion is not provided. It was confirmed that it can be curled towards. Further, it was confirmed that the sealing property was improved as compared with the case where the front suppressing portion was not provided.

  On the other hand, sample no. The evaluation in 4 was not good. From this, it is understood that the average tear strength in the MD direction is preferably 30 N / mm or less.

  In the present embodiment, the surface printing layer 32 is formed on substantially the entire surface of the base film 31 except for the unprinted area 33 on the front side at both ends in the direction orthogonal to the high stretching direction. As shown in FIG. 8, the front printing layer 32 is formed in an annular shape only in the peripheral area 30, and the inner portion (central area) may be an unprinted area 33, and at least the front printing is performed in the peripheral area 30. It is sufficient that the layer 32 is formed. The second back printed layer 36 may be omitted as shown in FIG. 8, and even when the second back printed layer 36 is formed, the size and shape as shown in FIG. It is not limited, and the number may be arbitrary and may be distributed at a plurality of locations. In such a case, in order to balance the shrinkage stresses on the front and back sides, it is preferable to provide the front print layer 32 on the surface of the base film 31 corresponding to the shape, number, and print location of the back print layer 36.

  Moreover, in the said embodiment, although the back suppression part was formed in the both ends of the direction orthogonal to the high extending | stretching direction, respectively, you may make it form a back suppression part only in either one. The same applies to the pair of left and right weakening lines 38. For example, when a back restraining portion is provided only at one end of both ends in the direction orthogonal to the high stretching direction, the weakening line 38 is provided near the back restraining portion. A pair of left and right may be formed. Of course, the weakening line 38 may be formed only on the left side or the right side in addition to the left and right pairs.

  In addition, although the shape of the heat-shrinkable film 2 for lids was circular in the state before heat-shrinking, it may be oval or oval long in the high stretching direction, or may be a polygon. However, it is preferable that the shape is similar to the shape of the opening 10 of the container 1. As in the examination results described above, a semi-circular or rectangular picking piece is projected as a portion to be the picking portion 22 at a predetermined position on the outer edge portion of the heat shrinkable film 2 for the lid before the heat shrinking. You may keep it.

DESCRIPTION OF SYMBOLS 1 Container 2 Heat-shrinkable film 10 for lid | covers Opening part 11 Bottom part 12 Side part 13 Flange part 13a Outer edge 20 Top surface part 21 Skirt part 22 Knob part 30 Peripheral area | region 31 Base film 32 Front printed layer 33 Unprinted area | region 34 on the front side Boundary line 35 First back printed layer 36 Second back printed layer 37 Unprinted area 38 on the back side Weak line 39 Boundary line X High stretch direction Y Direction perpendicular to high stretch direction

Claims (6)

A packaging body in which the opening of the container is covered with a heat-shrinkable film for a lid,
The heat-shrinkable film for the lid is composed of a uniaxial side highly stretched film, and includes a top surface portion covering the opening of the container and a skirt portion extending downward from the top surface portion,
The skirt portion includes a knob portion that is spaced outward from the side surface portion of the container at least at one end portion of both ends in a direction orthogonal to the high-stretching direction of the heat shrinkable film for lids. Packaging.   The package according to claim 1, wherein the knob portion is provided with a back suppressing portion in which a shrinkage suppressing layer is formed only on the back surface.   The package according to claim 1 or 2, wherein the skirt portion is provided with a front suppressing portion in which a shrinkage suppressing layer is formed only on the surface.   The package according to claim 3, wherein in the skirt portion, the front suppressing portion is provided between a boundary with the top surface portion and an inner edge of the back suppressing portion.   The package according to any one of claims 1 to 4, wherein a weakening line extending inward from the outer edge of the heat shrinkable film for lid is formed in the vicinity of the knob portion.   The heat-shrinkable film for lid | covers used for the package in any one of Claims 1 thru | or 5.

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