JP2014015215A - Seal structure for package and seal method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal structure for a package, the structure capable of reliably preventing a sealing failure and breakage of the seal structure by exerting adequate peeling strength while satisfying a good un-sealing performance.SOLUTION: A seal structure for a sealing portion of a package includes a first base sheet 1 and a second base sheet 2 that includes at least a sealant film, which are heat-sealed together. The sealant film of the second base sheet 2 is formed by a thermal plastic film having a melting point lower than that of the first base sheet 1. A seal surface is formed with a weld-control pattern 25 for controlling a thermal welding state of the sealant film. The weld-control pattern 25 is formed by a linear columnar linear pattern 26 produced by attaching and hardening droplets of infrared-setting resin ejected from an ink-jet printing head 17 onto the sealant film of the second base sheet 2.

Description

  The present invention relates to a sealing structure of a sealing portion of a package body such as a packaging bag or a blister pack, and a sealing method.

  Various proposals have been made regarding easy-openability of the seal structure of the package. For example, in the resin laminate of Patent Document 1, after a PE film layer is laminated on a PET resin film, an aluminum layer is formed on the PE film layer to constitute a laminated film. Further, an ethylene copolymer layer (sealant layer) is laminated on the surface of the aluminum layer by a T-die extrusion method, and a lattice-like uneven pattern is transferred to the surface of the ethylene copolymer layer immediately after being laminated by a gravure roll. ing. The adjacent pitch of the grating is 50 to 3000 μm, and the recess width is 20 to 500 μm. Moreover, when the thickness of the ethylene copolymer layer is 20 μm, the dent depth is 2 to 14 μm. According to this resin laminate, since the lattice-shaped uneven pattern is formed on the ethylene copolymer layer, it is possible to obtain a packaging film or sheet having excellent straight tearing properties while maintaining a certain peel strength.

  In the laminated packaging material of Patent Document 2, an adhesive layer, an intermediate layer, and a sealant layer are laminated in the order of description on one side of the film base material layer. The sealant layer is formed by laminating an adhesive resin layer and a low-temperature sealable resin layer on the surface of the intermediate layer by a T-die extrusion method, and the low-temperature sealable resin layer is formed by a gravure roll. ing. According to this laminated packaging material, since the recess is formed in the low-temperature sealing resin layer constituting the sealant layer, the easy-openability of the sealed portion can be improved.

  In the bag-shaped package of Patent Document 3, the film surfaces (sealant films) facing each other at the sealing portion are heat-sealed, but a print pattern is formed with normal printing ink on the film surface before heat-sealing. Easy opening of the seal part is improved. The print pattern is formed in a grid pattern, parallel diagonal lines (stripes), polka dot pattern, or a pattern in which a group of rectangles are alternately arranged, and the print pattern portion is not heat sealed, making it easy to open. Is realized. In addition, regarding the bag-shaped package of Patent Document 3, details of a film material to be sealed, details of a printing pattern and printing ink, heat sealing conditions, and the like are unknown.

JP 2009-255459 A (paragraph number 0040, FIG. 1) Japanese Patent Laying-Open No. 2004-098488 (paragraph number 0010, FIG. 1) JP-A-11-263373 (paragraph number 0010, FIG. 4)

  The packaging material of patent document 1 and patent document 2 forms an uneven | corrugated pattern or a recessed part in the sealant layer of a lamination sheet, and improves the easy-opening property of a sealing part. Therefore, the tear strength (peel strength) per unit area of the heat seal portion is always constant, and the tear strength changes in proportion to the area of the heat seal portion. In particular, when the area of the heat seal portion is large, the tear strength is increased more than necessary. When the area and arrangement density of the concavo-convex pattern are changed to large or small, the tear strength per unit area of the heat seal portion can be appropriately changed. However, for that purpose, it is necessary to prepare many kinds of gravure rolls for forming the uneven pattern, which increases the cost of the packaging material.

  In that respect, the packaging material of Patent Document 3 realizes easy opening by forming a non-adhesive print pattern on the film surface, so that the tear strength can be adjusted to a relatively low price simply by changing the print pattern. . However, the cost of changing the printing pattern is basically the same as that of the packaging materials of Patent Documents 1 and 2, and the pattern changing cost is less than when preparing many types of gravure rolls. It's just enough.

  Moreover, in the package body of patent document 3, by forming a printing pattern on the film surface used as a heat seal part, the peel strength is reduced by utilizing the fact that the printed part is not thermally welded, and the peeling force at the time of opening is increased. Can be small. However, in order to prevent the molten resin from receiving a sealing pressure and wrapping around the printed portion, it is necessary to form a printing pattern with a sufficient area, so that easy-openability is satisfied, but sufficient peel strength is obtained. There was a problem in that it was difficult to get. As described above, since the packaging body in which only easy-openability is regarded as important is difficult to obtain a sufficient peel strength, the sealing structure of the packaging body is easily broken at the distribution stage.

  In the package of Patent Document 3, the thermal welding strength (peel strength) can be adjusted by adjusting the area of the printed portion, the arrangement density of the printed pattern, and the like. However, in order to satisfy the conflicting requirements of peel strength and easy-openability, several types of prototype samples are formed, and the peel strength (peel strength) is confirmed by a predetermined test method for each prototype sample. The quality of the structure must be determined, and a lot of labor and time are required for a series of operations.

  In order to obtain a seal structure that satisfies the above-mentioned situation and satisfies the peel strength and easy-openability of the sealing portion, the present inventors have elucidated the correlation between the heat-sealed seal structure and the peeling force. Tried. Furthermore, as a result of exploring a sealing material suitable for easy opening in parallel, the present invention has been proposed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a package sealing structure and a sealing method thereof that can exhibit satisfactory peel strength while satisfying suitable easy-openability, and can reliably prevent seal failure and seal structure destruction. There is.

  In the sealing structure of the packaging body according to the present invention, the sealing structure in the sealing portion of the packaging body is configured by heat-sealing the first base material sheet 1 and the second base material sheet 2 provided with at least a sealant film. . The sealant film of the second base sheet 2 is formed of a thermoplastic plastic film having a melting point lower than that of the first base sheet 1, and a welding control pattern 25 for controlling the heat-welded state of the sealant film is provided on the sealing surface. Is formed. The welding control pattern 25 is characterized in that a droplet of an ultraviolet curable resin discharged from the ink jet type print head 17 is adhered to the sealant film of the second base sheet 2 and cured.

  The welding control pattern 25 is formed by a linear pattern 26 in a linear row. The linear pattern 26 in the present invention is a concept including a linear pattern as shown in FIGS. 10 (a) to 10 (i).

  The drawing width b of the linear pattern 26 formed on the sealant film of the second base sheet 2 is set to 80 to 500 μm.

  The 1st base material sheet 1 is formed with a high-density polyethylene nonwoven fabric. The sealant film of the second base sheet 2 is formed of a polyethylene resin. The welding control pattern 25 is formed of an acrylic ultraviolet curable resin.

  In the sealing method for a package according to the present invention, the first base sheet 1 and the second base sheet 2 provided with at least a sealant film are heat-sealed. Specifically, a welding control pattern for controlling the thermal welding of the sealant film by adhering and curing the ultraviolet curable resin droplets emitted from the inkjet print head 17 to the sealing surface of the sealant film of the second base sheet 2. Through a pattern forming step for forming 25 and a welding step for heat-sealing both base material sheets 1 and 2 in a state in which the second base material sheet 2 is overlapped on one side of the first base material sheet 1. A seal structure is formed.

  In the pattern forming step, while transporting the second substrate sheet 2 in one direction, the plurality of print heads 17 discharges the ultraviolet curable resin droplets toward the sealant film, and on the heat seal surface of the sealant film, A welding control pattern 25 including a linear pattern 26 is formed.

  The drawing width b of the linear pattern 26 formed on the sealant film of the second base sheet 2 is set to 80 to 500 μm.

  The 1st base material sheet 1 is formed with a high-density polyethylene nonwoven fabric, and the sealant film of the 2nd base material sheet 2 is formed with a polyethylene resin. The welding control pattern 25 is formed of an acrylic ultraviolet curable resin.

  In the present invention, the welding control pattern 25 for controlling the heat welding state of the sealant film is formed on the heat seal surface of the second base sheet (sealant film) 2. Further, the welding control pattern 25 is formed by adhering droplets of the ultraviolet curable resin released from the ink jet print head 17 to the sealant film of the second base sheet 2 and curing it. In this way, when the welding control pattern 25 is formed by the ink jet type print head 17, the welding control pattern 25 having an arbitrary width and arbitrary shape can be formed on the sealant film only by controlling the operation state of the print head 17 through software. It can be freely formed. Therefore, it is possible to easily change the pattern of the welding control pattern 25, change the pattern formation position, etc., and provide a seal structure suitable for high-mix low-volume production of packages having different seal structures.

  Further, since the droplets of the ultraviolet curable resin are attached to the sealant film and cured to form the welding control pattern 25, the line width and area of the pattern elements constituting the welding control pattern 25 are miniaturized as necessary, The peel strength (peeling force) of the heat seal part can be set precisely. Furthermore, when welding the sealing surface of the 2nd base material sheet 2 to the 1st base material sheet 1, the welding control pattern 25 of the solidified state is received on the surface of the 1st base material sheet 1, and sealant film of It is possible to ensure easy opening by restricting the penetration depth to be unnecessarily large by the welding control pattern 25. Therefore, as compared with the conventional seal structure that reduces the peel strength by printing normal printing ink on the film surface, it exhibits sufficient peel strength while satisfying a suitable easy-opening property, resulting in a seal failure or seal structure. It is possible to provide a sealing structure for a package that can reliably prevent damage to the package. When the second base sheet 2 is heat-sealed to the first base sheet 1, the cured welding control pattern 25 is not melted by receiving heat from the heat roller 14 or the heating and pressing block 15, Therefore, it is possible to reliably prevent the penetration depth of the sealant film from becoming unnecessarily large.

  If the welding control pattern 25 is formed by the linear pattern 26 in the linear row, the peel strength and the peeling force in the longitudinal direction of the linear pattern 26 can be made uniform, so that the second base sheet 2 (or the first 1) at the time of opening The peeling operation of the base material sheet 1) can be performed smoothly.

  The drawing width b of the linear pattern 26 is set to 80 to 500 μm because if the drawing width b is less than 80 μm, sufficient peel strength cannot be obtained, and there is a risk of seal failure or damage to the seal structure. It is. On the other hand, if the drawing width b exceeds 500 μm, the standard deviation of the average peeling force becomes large, and it becomes difficult to stably open with a substantially constant peeling force.

  When the 1st base material sheet 1 is formed with a high-density polyethylene nonwoven fabric, and the sealant film of the 2nd base material sheet 2 is formed with a polyethylene resin, only the sealant film is melted, and the melted portion of the first base material sheet 1 It can be melted into the surface. Specifically, the melted portion of the sealant film can be welded so as to be soaked between the non-woven fibers on the surface of the first base sheet 1, thereby making the sealant film stronger with respect to the first base sheet 1. Can be integrated into a sealing structure with excellent peel strength.

  According to the sealing method of the package according to the present invention, the welding control pattern 25 is formed by adhering and curing the droplets of the ultraviolet curable resin released from the print head 17 to the sealing surface of the sealant film, so that the welding control pattern 25 is formed. The pattern shape and pattern formation position of 25 can be freely changed. Further, the line width and area of the pattern elements constituting the welding control pattern 25 can be reduced as necessary, and the peeling force (peel strength) of the heat seal portion can be set accurately.

  As described above, after the droplets of the ultraviolet curable resin are attached and cured in the pattern forming process to form the welding control pattern 25, the second base sheet 2 is welded to the first base sheet 1 in the welding process. It is possible to provide a seal structure that satisfies the contradictory requirements of easy-openability and peel strength. In the pattern forming process, the line width and area of the pattern elements constituting the welding control pattern 25 can be reduced as necessary, and the peel strength of the heat seal portion can be set to a required value precisely. Furthermore, in the welding process, the welding control pattern 25 in a solid state is received on the surface of the first base sheet 1, and the welding control pattern 25 regulates that the penetration depth of the sealant film becomes unnecessarily large. And easy opening can be secured.

  In the pattern forming step, when the second base sheet 2 is conveyed in one direction and the droplets of the ultraviolet curable resin are ejected by the plurality of print heads 17 to form the welding control pattern 25, the welding control pattern 25 is quickly formed. Can be formed. In particular, when the welding control pattern 25 is constituted by a linear pattern 26, the pattern shape of the welding control pattern 25 is formed by individually forming the linear pattern 26 with a plurality of print heads 17. Can be changed continuously and variously.

  The drawing width b of the linear pattern 26 is set to 80 to 500 μm because if the drawing width b is less than 80 μm, sufficient peel strength cannot be obtained, and there is a risk of seal failure or damage to the seal structure. It is. On the other hand, if the drawing width b exceeds 500 μm, the standard deviation of the average peeling force becomes large, and it becomes difficult to stably open with a substantially constant peeling force.

  When the 1st base material sheet 1 is formed with a high-density polyethylene nonwoven fabric, and the sealant film of the 2nd base material sheet 2 is formed with a polyethylene resin, only the sealant film is melted, and the melted portion of the first base material sheet 1 It can be melted into the surface. Specifically, the melted portion of the sealant film can be welded so as to be soaked between the non-woven fibers on the surface of the first base sheet 1, thereby making the sealant film stronger with respect to the first base sheet 1. Can be integrated into a sealing structure with excellent peel strength.

It is a top view which shows the sealing structure of the package which concerns on this invention. It is explanatory drawing which illustrates the manufacturing process of the package which concerns on this invention. It is the sectional view on the AA line in FIG. It is an enlarged view which shows the measurement result of the drawing width of the linear pattern in Test 1. It is a graph which shows the relationship between the designated width | variety of a linear pattern, and drawing width. It is a graph which shows the measurement result of the average peeling force which concerns on the test 2. FIG. 6 is a chart showing measurement results of average peeling force according to Test 3. It is a graph which shows the dispersion | variation in the average peeling force which concerns on the test 3. FIG. It is a graph which shows the dispersion | variation in the peeling force in the middle of peeling. It is explanatory drawing which shows the specific example of a welding control pattern. It is a graph which shows the relationship between the average peeling force which concerns on Test 4, and drawing width. It is a chart which shows the relationship between the standard deviation of the average peeling force which concerns on Test 4, and drawing width. It is the chart and graph which show the measurement result of the line height of a linear pattern. It is an evaluation table | surface which shows the relationship between the drawing width of a linear pattern, and the dispersion | variation in peeling force.

(Embodiment) FIG. 1 thru | or FIG. 3 has shown embodiment of the sealing structure of the package which concerns on this invention, and demonstrates the case where the packaging object is the medical device M in this embodiment. The package is hermetically packaged with the medical device M according to the procedure shown in FIG. In FIG. 2, reference numeral 1 is a first base sheet, reference numeral 2 is a second base sheet, reference numeral 3 is a package supply booth for supplying the medical device M to the upper surface of the first base sheet 1, and reference numeral 4 is a welding booth. Reference numeral 5 denotes a cutting booth, reference numeral 6 denotes a pattern formation booth, reference numeral 7 denotes a pattern curing booth, and reference numeral 8 denotes a carry-out conveyor. The medical instrument M in this embodiment is a catheter.

  The 1st base material sheet 1 is drawn | fed out from the original fabric roll 11, and is conveyed at a fixed speed in order to the package supply booth 3, the welding booth 4, and the cutting | disconnection booth 5. FIG. Moreover, the 2nd base material sheet 2 is drawn | fed out from the original fabric roll 12, and goes through the pattern formation booth 6 and the pattern hardening booth 7, and with the 1st base material sheet 1 with which the medical instrument M was mounted on the upper surface. The welding booth 4 and the cutting booth 5 are sequentially conveyed at a constant speed. The 1st base material sheet 1 and the 2nd base material sheet 2 are intermittently conveyed synchronizing with the operation timing of the heating pressurization block 15 and the cutter 16 which are mentioned later.

  The welding booth 4 includes a pair of heat rollers 14 for heat-sealing both side edges in the width direction of the first base sheet 1 and the second base sheet 2 and a medical instrument M adjacent in the transport direction. A pair of heating and pressing blocks 15 for heat-sealing the sheets 1 and 2 are arranged. Further, inside the cutting booth 5, a cutter 16 for individually cutting a package in which the medical instrument M is packaged is disposed. A plurality of inkjet print heads 17 are arranged inside the pattern formation booth 6 provided in the conveyance path of the second base sheet 2, and an ultraviolet lamp 18 is arranged inside the pattern curing booth 7. ing.

  The external appearance of the package formed through a series of treatments is shown in FIG. The package is formed in a horizontally-long rectangular shape, the first seal portion 21 is formed on each of the long side portions, and the second seal portion 22 is formed on each of the short side portions. Of the pair of second seal portions 22, a tab portion 23 that is not heat-sealed is provided over the entire length of the short side portion outside the second seal portion 22 on the right side in FIG. 1. Thus, the packaging body in a present Example is comprised as a bag body of the four-side seal structure where each of the four side parts was heat-sealed by the 1st seal part 21 and the 2nd seal part 22. FIG. By grasping one end of the tab portion 23 with a fingertip and pulling the second base sheet 2, the first seal portion 21 and the second seal portion 22 are simultaneously peeled off as indicated by an imaginary line in FIG. 1. Thus, the package can be opened.

The first base sheet 1 was formed of a high-density polyethylene nonwoven fabric having moisture permeability in order to exhibit sufficient peel strength while satisfying easy-opening properties and to perform sterilization treatment in a packaged state. Moreover, the 2nd base material sheet 2 was formed only with the thermoplastic polyethylene resin sheet which has a lower melting | fusing point than a 1st base material sheet, and functions as a sealant film. Furthermore, the welding control pattern 25 which inhibits the heat welding of a sealant film was formed in the sealing surface of the 2nd base material sheet 2, and it was made possible to exhibit suitable easy-openability. As a specific example of the high density polyethylene nonwoven fabric constituting the first base sheet 1, Tyvek (registered trademark) commercially available from Asahi DuPont Flash Van Products Co., Ltd. is suitable. In this embodiment, the weighing is 74. The first base sheet 1 was formed from Tyvek (registered trademark) 1073B having a thickness of 6.8 g / m ² and a thickness of 178 μm. Moreover, the thickness of the 2nd base material sheet 2 which consists of a polyethylene resin sheet was 62 micrometers.

  The welding control pattern 25 is formed by discharging an acrylic ultraviolet curable resin from the print head 17 and attaching the discharged droplets to the second base sheet 2. Specifically, in synchronism with the conveying operation of the second base sheet 2, ultraviolet curable resin droplets are discharged from the print head 17 and solidified, and five welding control patterns 25 are formed at the position where the first seal portion 21 is formed. A parallel linear pattern 26 was formed. Further, in a state where the transport operation of the second base sheet 2 is temporarily stopped, the print head 17 is moved along the formation position of the second seal portion 22, and the welding control pattern having the same pattern as the first seal portion 21 is obtained. 25 was formed on the second seal portion 22. The linear pattern 26 in this example is the pattern shown in FIG. 10E, the drawing width b is 166 μm, and the pitch P of the adjacent linear patterns 26 is 1 mm.

  The first base sheet 1 and the second base sheet 2 are formed in the welding booth 4 such that the first seal portion 21 is first formed by the heat roller 14 and then the second seal portion 22 is formed by the heating and pressurizing block 15. Is done. At this time, the first base sheet 1 formed of Tyvek (registered trademark) hardly melts, the second base sheet 2 made of a polyethylene resin sheet melts, and the melted portion 28 becomes the first base sheet 1. Melt into the surface. However, as shown in FIG. 3, since the welding control pattern 25 formed on each of the seal portions 21 and 22 maintains a cured state, each linear pattern subjected to the pressure of the heat roller 14 and the heating and pressing block 15. 26 is received in a state of being slightly sunk into the surface of the first base sheet 1. As a result, the melted portion of the second base sheet 2 is restricted from being melted more deeply than necessary from the surface of the first base sheet 1, and the melted portion of the second base sheet 2 It welds so that it may penetrate between the nonwoven fabric fibers of the surface of the material sheet 1. The first seal part 21 and the second seal part 22 were welded using an auto sealer (model FA-300) manufactured by Fuji Impulse Corporation. The temperature setting dial was 4, the cooling setting was 5, and the pressure was at the standard position.

  In a conventional heat seal part, compatible films are melted together to form a seal structure. For this reason, the welding depth varies greatly between the films due to a slight difference in welding conditions, which causes the peel strength (peeling force) to vary. However, as described above, only the second base sheet 2 is melted, and the second base sheet 2 is prevented from deeply melting from the surface of the first base sheet 1 with the cured control pattern 25. Then, the melting depth of the second base sheet 2 can be made uniform. Therefore, the variation range of peel strength (peeling force) can be reduced, and a substantially constant peel strength can be exhibited. Further, since the welding control pattern 25 is simply pressed against the first base sheet 1, it is possible to realize easy opening of the seal structure by restricting the peeling force from becoming too large.

(Example) The present inventor conducted Tests 1 to 3 in order to elucidate the correlation between the heat-sealed seal structure and the peeling force and to optimize the peel strength and the easy-openability.

(Test 1) In Test 1, the designated width of the linear pattern 26 designated by the program for the print head 17 and the drawing width of the linear pattern 26 of the ultraviolet curable resin actually formed on the second substrate sheet 2 The relationship with b was confirmed. Specifically, when the designated width of the linear pattern 26 with respect to the print head 17 is set to 1 μm, 5 μm, 10 μm, 100 μm, 200 μm, 300 μm, 400 μm, and 500 μm, the linear shape formed on the second substrate sheet 2 It was measured how the drawing width b of the pattern 26 changed. The drawing width b is a width dimension in a state where ultraviolet rays are irradiated and cured after the ultraviolet curable resin droplets are discharged from the print head 17 to the sealant film. The results are shown in FIGS. 4 (a) to (h).

As shown in FIG. 4A, when the designated width of the linear pattern 26 with respect to the print head 17 is 1 μm, the drawing width b is 75 μm.
As shown in FIG. 4B, the drawing width b of the linear pattern 26 was 85 μm when the specified width for the print head 17 was 5 μm. In this case, the linear pattern 26 was a linear pattern in which a portion where droplets continued and a portion where droplets did not continue appeared randomly.
As shown in FIG. 4C, the drawing width b of the linear pattern 26 when the specified width for the print head 17 is 10 μm is 84 μm, which is almost the same as the drawing width b when the specified width is 5 μm. . The linear pattern 26 in this case was a linear pattern in which a portion where droplets are continuous and a portion where droplets are not continuous appear randomly.
As shown in FIG. 4D, the drawing width b of the linear pattern 26 is 166 μm when the specified width for the print head 17 is 100 μm. In this case, the linear pattern 26 was a linear pattern in which droplets overlap without interruption.
As shown in FIG. 4E, the drawing width b of the linear pattern 26 was 206 μm when the specified width for the print head 17 was 200 μm. In this case, the linear pattern 26 was a linear pattern in which droplets overlap without interruption.
As shown in FIG. 4F, the drawing width b of the linear pattern 26 was 333 μm when the specified width for the print head 17 was 300 μm. In this case, the linear pattern 26 was a linear pattern in which droplets overlap without interruption.
As shown in FIG. 4G, when the designated width for the print head 17 is 400 μm, the drawing width b of the linear pattern 26 is 401 μm. In this case, the linear pattern 26 was a linear pattern in which droplets overlap without interruption.
As shown in FIG. 4H, the drawing width b of the linear pattern 26 was 520 μm when the designated width for the print head 17 was 500 μm. In this case, the linear pattern 26 was a linear pattern in which droplets were densely concentrated in both the transport direction of the second base sheet 2 and the line width direction.

  The measurement result of the above test 1 is shown in FIG. In the logarithmic graph of FIG. 5, the horizontal axis indicates the width specified for the print head 17, and the vertical axis indicates the actual drawing width b. As can be understood from the measurement results, the horizontal axis is applied to a normal print head. The drawing width b of the ultraviolet curable resin having a large viscosity tends to be larger than the designated width as compared with the aqueous printing ink. Further, in the current print head 17, the drawing width b tends to be larger than the specified width as the specified width with respect to the print head 17 is small. When the specified width is 10 μm or less, the drawing width b is sufficiently large. I couldn't make it smaller. However, in the future, it is considered that the drawing width b can be controlled more precisely by improving the technology of the print head 17.

(Test 2) In Test 2, the first base sheet 1 and the second base sheet 2 are heat-sealed, and the second base sheet 2 is peeled off in the width direction of the heat seal portion. How the force changed was measured, and the average value and standard deviation of the peeling force were calculated from the results. Test 2 was performed according to the test method defined in JIS-Z-0238. In Test 2, Tyvek (registered trademark) having a thickness of 178 μm described above was used as the first base sheet 1, and a polyethylene resin sheet having a thickness of 62 μm was used as the second base sheet 2. 1 The base sheet 1 was heat sealed. In that case, the welding control pattern 25 was formed in the heat seal part of the 2nd base material sheet 2 by the five parallel linear patterns 26 shown in FIG.10 (e). The drawing width b of each linear pattern 26 was 166 μm (the specified width for the print head 17 was 100 μm), and the pitch P of the adjacent linear patterns 26 was 1 mm. FIG. 6 shows the test results. In FIG. 6, the horizontal axis indicates the position in the width direction from the peeling start end when the entire width of the heat seal portion is 20 mm, and the vertical axis indicates the peeling force.

  As can be seen from FIG. 6, the peeling force when the second base sheet 2 is peeled off is approximately linear from the peeling start end to the position of 5 mm in the width direction of the heat seal portion. To increase. However, when the position exceeds 5 mm in the width direction, the peeling force slightly decreases, and thereafter, the peeling force changes up and down repeatedly up and down to the position in the width direction 15 mm. That is, from the peeling start end to the position in the width direction of the heat seal part 5 mm, the second base sheet 2 and the first base sheet 1 are maintained in a welded state, and the peeling force is 4N. When it exceeds, the second base sheet 2 is peeled off from the first base sheet 1 and begins to separate.

  Further, if the position slightly exceeds 15 mm in the width direction, the peeling force decreases rapidly, and becomes zero after the position exceeding 18 mm in the width direction. This means that the second base sheet 2 is not welded to the first base sheet 1 at a position beyond the position of 18 mm in the width direction. From the above measurement results, it can be seen that the average value of the peeling force when the above welding control pattern 25 is formed on the heat seal portion is 3.3 N, and the standard deviation is as small as 0.4 N.

(Test 3) In Test 3, the change in the average peeling force when the drawing width b of the linear pattern 26 differs in size was measured. Specifically, the designated width of the linear pattern 26 with respect to the print head 17 is 1 (75) μm, 5 (85) μm, 10 (84) μm, 100 (166) μm, 200 (206) μm, 300 (333). ) Μm, 400 (401) μm, 500 (520) μm, the welding control pattern 25 was formed, and the average peeling force when both base sheets 1 and 2 were heat sealed was measured. The dimensions in parentheses are the actual drawing width b. For comparison, the average peeling force of Comparative Example 1 and Comparative Example 2 was measured when both base sheets 1 and 2 were heat sealed without forming the welding control pattern 25. The result is shown in FIG. 7, the horizontal axis shows the heat seal welding control pattern 25 shown in FIGS. 10 (a) to 10 (i), and the vertical axis shows the average peeling force.

As can be seen from FIG. 7, when the drawing width b of the linear pattern 26 is 75 μm (specified width is 1 μm), the average peeling force when the second base sheet 2 is peeled off is 3.2 N. The standard deviation is 0.1N.
When the drawing width b of the linear pattern 26 is 85 μm (specified width is 5 μm), the average peeling force is 5.6 N, and its standard deviation is 0.4 N.
When the drawing width b of the linear pattern 26 is 84 μm (specified width is 10 μm), the average peeling force is 6.1 N, and its standard deviation is 0.4 N.
When the drawing width b of the linear pattern 26 is 166 μm (specified width is 100 μm), the average peeling force is 4.9 N, and its standard deviation is 0.9 N.
When the drawing width b of the linear pattern 26 is 206 μm (specified width is 200 μm), the average peeling force is 5.8 N, and its standard deviation is 0.2 N.
When the drawing width b of the linear pattern 26 is 333 μm (specified width is 300 μm), the average peeling force is 5.7 N, and its standard deviation is 0.4 N.
When the drawing width b of the linear pattern 26 is 401 μm (specified width is 400 μm), the average peeling force is 5.1 N, and its standard deviation is 0.6 N.
When the drawing width b of the mark-like pattern 26 is 520 μm (specified width is 500 μm), the average peeling force is 4.7 N, and its standard deviation is 0.6 N.
The average peeling force of Comparative Example 1 in which the base material sheets 1 and 2 are heat sealed without forming the welding control pattern 25 is approximately 4.3 N, but the standard deviation is 0.8 N.
The average peeling force of Comparative Example 2 in which the base material sheets 1 and 2 are heat-sealed without forming the welding control pattern 25 is 5.3 N, but the standard deviation is 0.7 N.

  Variations in the average peeling force calculated from the measurement results of FIG. 7 are collectively shown in FIG. Further, FIG. 9 shows the variation of the peeling force in the middle of peeling calculated from the measurement result of FIG.

  As can be understood from FIG. 8, the heat seal portion where the welding control pattern 25 is formed has the same or rather peel strength (peeling strength) compared to the heat seal portion where the welding control pattern 25 is not formed. It is improved and it can be seen that sufficient peel strength can be exhibited. Further, among the heat seal portions where the welding control pattern 25 is formed, the peel strength is the smallest at the drawing width b of 75 μm (designated width is 1 μm), and the lower limit value of the designated width is between the drawing width b of 75 μm and 85 μm. Presumed to be.

  As can be understood from FIG. 9, the standard deviation of the peeling force when the specified width of the linear pattern 26 is 1 μm, 5 μm, 10 μm, 100 μm, 200 μm, 300 μm is gathered in a substantially narrow region, and the variation width Is small. When the specified width of the linear pattern 26 is 400 μm or 500 μm, the standard deviation of the average peeling force varies in a state that approximates a heat seal portion where the welding control pattern 25 is not formed.

  In addition, when the specified width is 10 μm, a peculiar measurement result appears in part, and this is presumed to be due to the stringing phenomenon. In the stringing phenomenon, the non-woven fiber of the first base sheet 1 remains stuck to the second base sheet 2 in the heat-sealed area of 20 mm in width, and outside the non-heat-sealed area of 20 mm in width. Is a phenomenon in which the nonwoven fabric fibers are peeled off. The stringing phenomenon should be avoided for quality control, but by forming the welding control pattern 25 in the heat seal portion, the melted second base material sheet 2 sinks into the first base material sheet 1 more than necessary. Therefore, the occurrence of the stringing phenomenon can be avoided as much as possible. In summary, the drawing width b of the linear pattern formed on the second base sheet (sealant film) 2 can be practically used if it is within the range of 80 to 500 μm, but is within the range of 80 to 350 μm. The drawing width b of the linear pattern should be selected within the range of 85 to 166 μm where the variation width of the average peeling force is small.

FIG. 10 shows a specific example of the welding control pattern 25.
In FIG. 10A, the welding control pattern 25 is formed with only one linear pattern 26.
In FIG. 10B, the welding control pattern 25 is formed by two linear patterns 26. In that case, the pitch of the adjacent linear patterns 26 was 2 mm.
In FIG. 10C, the welding control pattern 25 is formed by three linear patterns 26. In that case, the pitch of the adjacent linear patterns 26 was 1 mm.
In FIG. 10D, the welding control pattern 25 is formed by four linear patterns 26. In that case, the pitch of the adjacent linear patterns 26 was 1 mm.
In FIG. 10 (e), the welding control pattern 25 is formed by five linear patterns 26. In that case, the pitch of the adjacent linear patterns 26 was 1 mm.

In FIG. 10 (f), the welding control pattern 25 is formed by a linear pattern 26 in which> -shaped pattern elements 26a are arranged in a straight line at regular intervals. In this case, the pattern elements 26a in the straight line direction are arranged so that the tops and the open ends are located on the same vertical line. Further, the length of each inclined line of the> -shaped pattern element 26a was 5.6 mm.
In FIG. 10G, the welding control pattern 25 is formed by the linear pattern 26 in which the <-shaped pattern elements 26a are arranged in a straight line at regular intervals. In this case, the pattern elements 26a in the straight line direction are arranged so that the tops and the open ends are located on the same vertical line. Further, the length of each inclined line of the> -shaped pattern element 26a was 5.6 mm.

In FIG. 10 (h), the welding control pattern 25 is formed by the linear pattern 26 in which the O-shaped pattern elements 26a are arranged in a straight line at regular intervals. In this case, the adjacent pitch of the pattern elements 26a in the direction of the straight line is 5 mm. Moreover, the diameter dimension of the circle-shaped pattern element 26a was 1 mm.
In FIG. 10I, the welding control pattern 25 is formed by a linear pattern 26 in which I-shaped pattern elements 26a are arranged in a straight line at regular intervals. In this case, the adjacent pitch of the pattern elements 26a in the straight line direction was 5 mm, and the vertical length of the I-shaped pattern elements 26a was 5 mm.

  Test 4 was performed in order to confirm the difference in the average peeling force based on the difference in the linear pattern 26. There, the average peeling force when the specified width is 1 μm, 5 μm, 10 μm, 100 μm, 200 μm, 300 μm, 400 μm, and 500 μm was measured for the linear pattern 26 of FIGS. 10 (a) to 10 (i). . For comparison, the average peeling force when both base sheets 1 and 2 were heat sealed without forming the welding control pattern 25 was measured. The result is shown in FIG. 11. The horizontal axis indicates the designated width of the linear pattern 26, and the vertical axis indicates the average peeling force. No on the right end of the horizontal axis indicates a case where the welding control pattern 25 is not formed.

  As can be understood from FIG. 11, when the welding control pattern 25 is not formed (No), the average peeling force has a maximum value of 5.6 N and a minimum value of 2.6 N, and the peeling force has a large variation. I know that there is. On the other hand, in the case of the single linear pattern of FIG. 10A, the peeling force is 2.5 to 3.8 N, which is smaller than the average peeling force of No. However, in other linear patterns other than the linear pattern of FIG. 10A, an average peeling force that is approximately the same as or larger than the average peeling force of No can be exhibited. From the above results, it can be said that when the peeling force of the same level as in the case of No is required, the drawing width b needs to be 84 μm or more rather than the difference in the linear pattern 26.

  FIG. 12 is a chart showing the relationship between the standard deviation of the peeling force calculated from the measurement result obtained in Test 4 and the drawing width b. In this case, the standard deviation is used as an index of the variation in the peeling force. In FIG. 12, the horizontal axis indicates the designated width of the linear pattern 26, and the vertical axis indicates the average peeling force. Further, No at the right end of the horizontal axis in FIG. 12 indicates a case where the welding control pattern 25 is not formed.

  In the case of No in FIG. 12, the standard deviation varies greatly in the range of 0.4 to 2.3N. This means that the peeling force varies greatly depending on the place where the peeling force is peeled off, and the required peeling force has a width of ± 2.6 N with respect to the average peeling force. A similar tendency appears when the specified width is 500 μm. On the other hand, when the specified width is 1, 5, 10, 100, and 200 μm, the standard deviation is within the range of 0.3 to 0.8 N. The width is narrower by about one third when the width is 500 μm. Therefore, when the specified width is 1 to 100 μm, the required peeling force is ±± at most with respect to the average peeling force regardless of the linear pattern regardless of the linear pattern. It will be less than 0.8N. In other words, when the welding width 25 is set to 84 to 166 μm and the welding control pattern 25 is formed, the peeling force is prevented from varying in the peeling process, and the seal structure can be opened more smoothly.

  FIG. 13 is a chart showing the results of measuring the line height (thickness) of the linear pattern 26, and a graph showing the situation of variations in line height. As for the line height, when the designated width of the linear pattern 26 is 1, 100, 200, 300, 400, and 500 μm, different portions were measured three times, and the average value and the standard deviation were calculated. In the graph, the horizontal axis indicates the designated width of the linear pattern 26, and the vertical axis indicates the line height and its variation width. As can be understood from the measurement result, the line height of the linear pattern 26 is substantially the same value, and it is understood that the line pattern 26 is hardly influenced by the difference in the designated width of the linear pattern 26. Overall, the average line height is 55.2 μm and the standard deviation is 6 μm. If necessary, the welding control pattern 25 is formed and solidified, and then the welding control pattern 25 is formed again on the outer surface of the welding control pattern 25 and solidified a plurality of times to obtain the required line height. The welding control pattern 25 can be formed.

  FIG. 14 is an evaluation table showing the relationship between the drawing width of the linear pattern and the variation in peeling force. In this evaluation table, when the allowable standard deviation is defined as 1N in FIG. 9, the standard deviation exceeding the allowable standard deviation is considered to have a large variation in peeling force, and the number of occurrences of standard deviation exceeding the allowable standard deviation is considered. The degree of variation was evaluated.

  In the evaluation table of FIG. 14, when the specified width of the linear pattern 26 is 1 to 200 μm, among the nine types of welding control patterns 25, the specified width is 5 μm and the welding control pattern 25 is shown in FIG. In some cases, when the specified width is 10 μm and the welding control pattern 25 is FIG. 10B, and when the specified width is 100 μm and the welding control pattern 25 is FIG. 10B, the allowable standard deviation is exceeded. Variation has occurred. On the other hand, when the specified width of the linear pattern 26 is 300, 400, and 500 μm, and in Comparative Examples 1 and 2 in which the welding control pattern 25 is not formed, a variation exceeding the allowable standard deviation occurs in at least four locations. ing. From the above results, it can be seen that the specified width needs to be set to 200 μm or less in order to give stable peeling strength. This tendency does not depend on the difference in the type of the welding control pattern 25, and it can be said that it is characterized mainly by the difference in the designated width of the linear pattern 26. Note that when the specified width is 5, 10, 100 μm, the variation exceeding the allowable standard deviation is caused by the stringing phenomenon described above, and is caused by the difference in the type of the welding control pattern 25. Although the stringing phenomenon can be reduced, it cannot be eliminated at present.

  As described above, when the variation in the peeling force is stopped within a narrow range, anyone can accurately perform the opening operation of the package. Also, in the near future, it is possible to imagine a scene in which a care robot opens a package containing the medical device M. In such a case, it is possible to accurately open the package. Become. The care robot is expected to be programmed to open the package with a pre-specified range of forces. In such a case, if the peel-off force of the package greatly varies and exceeds the force specified by the care robot, the care robot cannot open the package, and the medical device M can be taken out. become unable. Moreover, when the peeling force of a package is smaller than the force of the range designated as the care robot, there is a possibility that the package is unsealed and the medical instrument M pops out. As described above, configuring the package seal structure with the specified range of peeling force is an important factor in promoting the introduction of nursing robots in nursing care sites where labor shortages are expected. be able to. The drawing width b of the linear pattern when opening the package with the care robot is preferably selected within the range of 80 to 350 μm, and more preferably within the range of 85 to 166 μm where the variation width of the average peeling force is small. It is good to select within.

  In the above-described embodiment, the four-side seal bag has been described. However, the package according to the present invention includes a three-side seal bag sealed with a back-and-forth joint, a flat bag with an envelope, or a gusset bag having a gusset portion, a blister pack, etc. Applicable to. Further, the packaging object M accommodated in the package may be food, industrial products, or the like. The second base sheet 2 can be formed of a laminated sheet in which a film or sheet having a higher melting point than the sealant film is laminated on one side of the sealant film. The sealant film can be formed of a thermoplastic plastic film other than polyethylene resin. For example, the sealant film can be formed of a thermoplastic plastic film having a higher melting point than the first base sheet 1 such as polypropylene.

DESCRIPTION OF SYMBOLS 1 1st sheet base material 2 2nd sheet base material 17 Print head 18 Ultraviolet lamp 21 1st seal | sticker part 22 2nd seal | sticker part 25 Welding control pattern

Claims (8)

The sealing structure in the sealing portion of the package is configured by heat-sealing the first base sheet (1) and the second base sheet (2) provided with at least a sealant film,
The sealant film of the second substrate sheet (2) is formed of a thermoplastic plastic film having a melting point lower than that of the first substrate sheet (1), and the welding control controls the heat-welded state of the sealant film on the seal surface. A pattern (25) is formed,
The welding control pattern (25) is formed by adhering the ultraviolet curable resin droplets released from the ink jet print head (17) to the sealant film of the second base sheet (2) and curing it. The seal structure of the package body characterized.   The seal structure for a package according to claim 1, wherein the welding control pattern (25) is formed in a linear pattern (26).   The package sealing structure according to claim 2, wherein a drawing width (b) of the linear pattern (26) formed on the sealant film of the second base sheet (2) is set to 80 to 500 µm. The first base sheet (1) is formed of a high-density polyethylene nonwoven fabric, the sealant film of the second base sheet (2) is formed of a polyethylene resin,
The sealing structure for a package according to claim 2 or 3, wherein the welding control pattern (25) is formed of an acrylic ultraviolet curable resin. A sealing method for a package formed by heat-sealing a first base sheet (1) and a second base sheet (2) provided with at least a sealant film,
Welding control for controlling thermal welding of the sealant film by adhering and curing the UV curable resin droplets released from the inkjet print head (17) to the sealing surface of the sealant film of the second base sheet (2). A pattern forming step of forming and curing the pattern (25);
In a state where the second base sheet (2) is overlapped on one side of the first base sheet (1), a welding step of heat-sealing both base sheets (1, 2),
A sealing method for a packaging body, wherein a sealing structure is formed on the packaging body.   In the pattern forming step, the second base sheet (2) is conveyed in one direction, and a plurality of print heads (17) are used to discharge ultraviolet curable resin droplets toward the sealant film, thereby forming a sealant film. The method for sealing a package according to claim 5, wherein a welding control pattern (25) comprising a linear array of linear patterns (26) is formed on the heat sealing surface.   The packaging body sealing method according to claim 6, wherein a drawing width b of the linear pattern (26) formed on the sealant film of the second base sheet (2) is set to 80 to 500 µm. The first base sheet (1) is formed of a high-density polyethylene nonwoven fabric, the sealant film of the second base sheet (2) is formed of a polyethylene resin,
The method for sealing a package according to claim 6 or 7, wherein the welding control pattern (25) is formed of an acrylic ultraviolet curable resin.