Patent Publication Number: US-2013248398-A1

Title: Continuous packing product of absorbent articles, exterior sheets, and method of manufacturing continuous packing product of absorbent articles

Description:
TECHNICAL FIELD 
     The present invention relates to a continuous packing product, of absorbent articles, in which a continuous plurality of packing units which include the absorbent articles are provided. BACKGROUND ART 
     In general absorbent articles such as sanitary napkins are sold in a manner in which a predetermined quantity of the absorbent articles are contained in a package which is formed by employing an exterior sheet such as a resin film. 
     In addition, it is widely known, mainly among developing countries that packing bodies for individually packing absorbent articles on one-by-one piece basis are sold in the manner of a continuous packing product in which a continuous plurality of packing units are provided in a longitudinal direction. A demander can purchase any required number of absorbent articles by separating a desired number of packing units from the continuous package of packing units. In addition, since the plurality of packing units that are continuous in the longitudinal direction can be sold while these packing bodies are hooked in an appropriate location in shop, it is convenient where there is limited space in a shopping facility. Patent Document 1 describes a continuous packing unit of absorbent articles in which packing units for individually housing the absorbent articles are continuous in plurality. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] International Patent Application Publication No. 02/094678 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, conventional continuous packaging of absorbent articles has entailed the following problem. That is, since the continuous packing unit houses the absorbent articles therein on one-by-one piece basis, a large number of packing bodies are formed in comparison with packaging which contains some tens of absorbent articles. Therefore, an improvement in productivity of packing bodies is required. 
     For example, as such a method of manufacturing a continuous packaging of absorbent articles, the absorbent articles are continuously packed by means of exterior sheets, and then, the exterior sheets are thermally bonded to form a plurality of packing bodies which are continuous. In an attempt to improve productivity in such a manufacturing method, it is considered to reduce bonding time of the exterior sheet. However, if the bonding time is reduced, heat may not be sufficiently transmitted to the exterior sheet, and bonding faults may occur. 
     Therefore, it is an object of the present invention to provide a continuous packing product of absorbent articles, which are efficiently produced while preventing an occurrence of a fault in thermal bonding; a method of manufacturing a continuous packing product of absorbent articles which are adapted to manufacture the continuous packing unit of the absorbent articles; and exterior sheets for forming the continuous packing product of absorbent articles. 
     Solution to Problem 
     The first feature of the present invention is summarized in that A continuous packing product of absorbent articles in which a plurality of packing units are continuous, with one or more absorbent articles being packed in each unit by means of an exterior sheet, wherein: the exterior sheet has: a first resin layer which is formed of a thermoplastic resin; and a second resin layer which is formed of a thermoplastic resin with a melting point higher than that of the thermoplastic resin forming the first resin layer; the exterior sheet comprises a thermally bonded product partition region configured to partition the packing product into packing units; the second resin layer is laminated on the first resin layer in at least the bonded region; and the thermoplastic resin of the second resin layer is soluble in a solvent. 
     The second feature of the present invention is summarized in that A continuous packing product of absorbent articles comprising a plurality of packing units which are individually packed by means of an exterior sheet, wherein: the exterior sheet has: a first resin layer which is formed of polyethylene; a second resin layer which is formed by applying a solution obtained by dissolving polyamide in a solvent; and a print layer which is disposed between the first resin layer and the second resin layer; and a thermally bonded partition region configured to partition the packing units by means of thermal bonding is formed on the exterior sheet. 
     The third feature of the present invention is summarized in that An exterior sheet provided with a partition region configured to pack continuously disposed absorbent articles and separately partition the absorbent articles by means of thermal bonding, wherein: the exterior sheet has: a first resin layer which is formed of a thermoplastic resin; and a second resin layer which is formed of a thermoplastic resin with a melting point higher than that of the thermoplastic resin forming the first resin layer; the second resin layer is laminated on the first resin layer in at least the partition region; and the thermoplastic resin configuring the second resin layer is soluble in a solvent. 
     The fourth feature of the present invention is summarized in that A method of manufacturing a continuous packing product of absorbent articles, comprising: a first step of, in a resin film formed of a thermoplastic resin, forming an exterior sheet by applying a solution which is obtained by dissolving in a solvent a thermoplastic resin with a melting point which is higher than that of the thermoplastic resin forming the resin film; a second step of continuously disposing absorbent articles each on the resin film of the exterior sheet; a step of folding the exterior sheet and the absorbent article along a direction which is orthogonal to a continuous direction in which the absorbent articles are continuous, and then, wrapping the absorbent article by means of the exterior sheet; and a fourth step of partitioning the exterior sheet having the absorbent article wrapped thereby, by means of thermal bonding, and then, continuously forming a plurality of packing units by which the absorbent articles are packed. 
     Advantageous Effects of Invention 
     According to characteristics of the present invention, there can be provided a continuous packing product of absorbent articles which are efficiently produced while preventing an occurrence of a fault in thermal bonding. That is, productivity of the continuous packing product of the absorbent articles can be improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an entire perspective view of a continuous packing product of absorbent articles, according to an embodiment of the present invention. 
         FIG. 2  is a perspective view showing a packing unit according to the embodiment of the present invention. 
         FIG. 3  is a sectional view of the packing unit taken along the line A-A of  FIG. 2 . 
         FIG. 4  is a sectional view of the packing unit taken along the line B-B of  FIG. 2 . 
         FIG. 5  is a sectional view of the packing unit taken along the line C-C of  FIG. 2 . 
         FIG. 6  ( a ) to ( e ) are views showing a process for manufacturing a continuous packing product, according to the embodiment of the present invention. 
         FIG. 7  ( a ) to ( d ) are views showing a process for manufacturing a continuous packing product, according to the embodiment of the present invention. 
         FIG. 8  ( a ) to ( d ) are schematic sectional views of an exterior sheet according to an exemplary modifications. 
         FIG. 9  is a sectional view of a packing unit according to an exemplary modification. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Next, an embodiment of a continuous packing product  1  of absorbent articles  10 , according to the present invention, will be described with reference to the drawings. In the description of the drawings that follows, the same or similar constituent elements are designated by the same or similar reference numerals. However, it should be kept in mind that the drawings are merely schematic and rates of dimensions each are different from an actual one. Therefore, specific dimensions or the like should be determined in consideration of the following description. In addition, portions whose dimensional interrelations or rates are different from each other can be included in the drawings as well. 
     First, a schematic structure of a continuous packing product  1  of the absorbent articles  10  (hereinafter, referred to as the continuous packing product  1 ) will be described with reference to  FIG. 1  to  FIG. 5 .  FIG. 1  is an entire perspective view of the continuous packing product  1  according to the embodiment. As shown in  FIG. 1 , the continuous packing product  1  is formed by absorbent articles  10  which are sanitary napkins and exterior sheets  3  for wrapping the absorbent articles  10 . The exterior sheets  3  are formed in a continuous sheet shape, and are adapted to pack the absorbent articles  10  in the shape of a bag. 
     Partition units  5  for partitioning the absorbent articles that are wrapped by the exterior sheets  3  on a one-by-one piece basis are formed at the continuous packing product  1 . Each of the partition units  5  is formed by a bonded region  3 C of the exterior sheet  3  (refer to  FIG. 2 ) being bonded by means of thermal bonding (deposition). By means of the partition units  5 , a plurality of packing bodies  2  for packing the absorbent articles  10  on one-by-one piece basis are continuously formed. In addition, five packing bodies  2  are continuous, and one continuous packing product  1  is formed. 
     In addition, a cutoff line unit  4  to which perforation processing is applied is formed at the partition unit  5 , and packing bodies  2  can be separated from the continuous packing product  1  according to a required number of absorbent articles  10 . 
       FIG. 2  is a perspective view showing a packing unit  2  which is separated from the continuous packing product  1 .  FIG. 3  is a sectional view of the packing unit  2  taken along the line A-A of  FIG. 2 .  FIG. 4  is a sectional view of the packing unit  2  taken along the line B-B of  FIG. 2 .  FIG. 5  is a sectional view of the packing unit taken along the line C-C of  FIG. 2 . 
       FIG. 3  is a sectional view of a packing unit  2  in a continuous direction D 2  in which the packing bodies  2  extend continuously;  FIG. 4  is a sectional view of a partition region  5  of the packing unit  2 . The partition region  5  is provided at the bonded region  3 C of the exterior sheet  3 . A partition region  5  on which the exterior sheet  3  is deposited is at each end part of the packing body  2  in  FIG. 3 . The exterior sheet  3  has a first resin layer  31 , a second resin layer  32 , and a print layer  33 . The first resin layer  31  is formed of a thermoplastic resin with a comparatively low melting point (relative to the second layer  32 ), which is melted by means of thermal bonding. Polyethylene can be employed, for example, as a material for the first resin layer  31 , and further preferably, a straight chain-like low density polyethylene (LLDPE) and a low density polyethylene (LDPE) can be employed. 
     Since polyethylene is comparatively low in melting point among thermoplastic resins (for example, in comparison with polypropylene), it is possible for resin layer  31  to have a difference in melting point to a resin forming the second resin layer  32 . Therefore, when thermal bonding is done, only the first resin layer  31  can be melted without melting the second resin layer  32 . In addition, since polyethylene UV-resistance (ultraviolet-ray resistance), it is possible to prevent degradation due to the UV of the absorbent articles that are housed therein. 
     The second resin layer  32  is a thermoplastic resin having a higher melting point than that of the thermoplastic resin forming the first resin layer, and may be formed of a resin which is soluble in solvent. The second resin layer is formed of a thermoplastic resin which is insoluble by means of thermal bonding, and is adapted to thermally resist and protect the first resin layer  31  without being melted at the time of thermal bonding. Polyamide such as nylon or imide can be exemplified as a material for the second resin layer  32 . 
     Any solvent may be employed as long as it melts the thermoplastic resin forming the second resin layer  32 , and a hydrocarbon having its boiling point of 150 degrees or less can be exemplified. Solvents include, but are not limited to, hexane, xylene, toluene, ethyl acetate, butyl acetate, isopropanol, butanol, and methyl ethyl ketone. 
     The print layer  33  is disposed between the first resin layer  31  and the second resin layer  32 . A method of forming the print layer is not limited. For example, the print layer  33  may be formed by means of a printing method such as flexographic printing, a sink printing or the like, or alternatively, may be formed by blowing ink through spraying. In addition, by providing the print layer  33 , visible light can be hardly transmitted, and then, the absorbent articles  10  that are housed therein can be hardly visually recognized from the outside of the exterior sheets  3 . 
     The exterior sheet  3  is disposed so that the second resin layer  32  configures an outside face  7 B of the exterior sheet  3  and the first resin layer  31  configures an inside face  7 A of the exterior sheet  3 . Thermal bonding is done from the outside face side of the exterior sheet  3 , whereby the first resin layer  31  is melted, the exterior sheet  3  of a bonding region  3 C is bonded therewith, and the partition region  5  is formed. 
     In addition, as shown in  FIG. 2  and  FIG. 5 , the packing unit  2  may be formed, in some embodiments, with the absorbent article  10  and the exterior sheet  3  folded together in a state in which a back face  6 B which is a cloth (clothing) contact surface of the absorbent article  10  and the inside face  7 Af the exterior sheet  3  are opposite to each other. 
     Specifically, the exterior sheet  3  is disposed at the side of the back face  6 B of the absorbent article  10 , and then, at least a part of the back face  6 B of the absorbent article  10  is fixed to the inside face  7 A of the exterior sheet  3 . The back face  6 B of the absorbent article  10  and the inside face  7 A of the exterior sheet  3  are fixed to each other via an adhesive unit  14  and an adhesive unit  15 . The absorbent article  10  and the exterior sheet  3  that are fixed to each other by means of the adhesive unit  14  and the adhesive unit  15  are folded into three together along a folding direction D 1  toward the side of the surface  6 A which is a skin contact surface of the absorbent article  10 . 
     The absorbent article  10  and the exterior sheet  3  are folded together, whereby an overlap region  21  (refer to  FIG. 2 ) in which an end part  3 A and an end part  3 B in the folding direction D 1  of the exterior sheet  3  are superimposed on each other is formed. At the packing unit  2 , an opening cutoff line part  8  is formed along a continuous direction D 2  in which the packing units  2  are continuous. The opening cutoff line part  8  is cut off, whereby the packing unit  2  is released, and then, the absorbent article that is housed therein is exposed. 
     A bonding region  22  (refer to  FIG. 2 ) in which the end part  3 A and the end part  3 B of the exterior sheet  3  are bonded with each other is formed at a part of the overlap region  21 . The bonding region  22  is formed by being adhesively bonded by means of thermal bonding, a biting emboss, an adhesive agent, an adhesive tape or the like. 
     The partition region  5  that corresponds to the bonded region  3 C of the exterior sheet  3  is at each end part of the packing bodies  2  in a continuous direction D 2  in which the packing bodies  2  are continuous. Since the partition region  5  is adhesively bonded by means of thermal bonding of the exterior sheet  3 , the absorbent article  10  is established in a sealed sanitary state. 
     Next, a method of manufacturing a continuous packing product  1 , according to the embodiment, will be described. Herein, in particular, a method of manufacturing exterior sheets  3  and a continuous packing product  1  will be mainly described. Other portions such as the absorbent articles  10  can be manufactured in accordance with well known manufacturing methods. 
       FIG. 6  and  FIG. 7  are views schematically showing a process of manufacturing a continuous packing product  1 .  FIG. 6  shows a cross section taken along a conveyance direction MD of absorbent articles  10 ; and  FIG. 7  is a perspective view of the absorbent article  10  and the exterior sheet  3 . As shown in  FIG. 6  and  FIG. 7 , the process of manufacturing a continuous packing product  10  includes: a print layer forming step S 10 ; a second resin layer forming step S 20 ; an absorbent article placement step S 30 ; a folding step S 40 ; an exterior sheet bonding step S 50 ; a packing body forming step S 60 ; and a cutoff line part forming step S 70 . The print layer forming step S 10  and the second resin layer forming step S 20  are included in the process of manufacturing exterior sheets  3 . In addition, the folding step S 40 , as shown in  FIG. 6 , includes a first folding step S 41  and a second folding step S 42 . 
     In the print layer forming step S 10 , as shown in  FIG. 6  ( a ), gravure printing is applied to the first resin layer  31  made of a resin film, and then, the print layer  33  is formed. An applying device for applying gravure printing is provided with: a reservoir unit  101  in which ink is reserved; a transfer roll  102  to which ink is transferred from the reservoir unit  101 ; and an applying roll  103  to which ink is transferred from the transfer roll  102 . Ink is applied to the first resin layer  31  by means of the applying roll  103 . 
     In the second resin layer forming step S 20 , as shown in  FIG. 6  ( b ), the second resin layer  32  is formed on the print layer  33 . Specifically, a solution obtained by melting a nylon, which is a thermoplastic resin with higher melting point than that of the resin forming the first resin layer  31 , in hexane as a solvent, is applied onto the print layer  33 . The applying device for applying a solution is similar to that in the print layer forming step S 10 , and therefore, a duplicate description is omitted. In this manner, since the print layer forming step S 10  and the second resin layer forming step S 20  can be carried out by means of the applying device having the similar structure, both of these steps can be carried out in the same facility, and productivity can be improved. In addition, the exterior sheets  3  are manufactured by means of the print layer forming step S 10  and the second resin layer forming step S 20 . 
     In the absorbent article placement process S 30 , as shown in  FIG. 6  ( c ) and  FIG. 7  ( a ), the absorbent articles  10  are fixed at predetermined intervals on the exterior sheets  3  which are continuous along the conveyance direction MD. At this time, the exterior sheet  3 , the first resin layer  31 , and the back face of the absorbent article  10  are opposite to each other and are disposed so that a lengthwise direction of the absorbent article  10  is orthogonal to the conveyance direction MD. 
     A folding step S 40  has the first folding step S 41  shown in  FIG. 7  ( b ) and the second folding step S 42  shown in  FIG. 7  ( c ). In the first folding step S 41 , the exterior sheet  3  and the absorbent article  10  are lifted from one end side in the folding direction D 1  that is orthogonal to the conveyance direction MD, and then, are folded together toward a centerline CL in the folding direction D 1 . A folding line of the exterior sheet  3  and the absorbent article  10  that have been folded is taken along the continuous direction D 2  that is parallel to the conveyance direction MD. 
     In the second folding step S 42 , the exterior sheet  3  and the absorbent article  10  are lifted from the opposite side from that of the first folding step S 41 , and then, are folded together toward the centerline CL in the folding direction D 1 . By means of this step, the overlap region  21  ( FIG. 2 ) is formed at continuous packing bodies  2 .  FIG. 6  ( d ) shows the exterior sheet  3  and the absorbent article  10  which are folded by means of the folding step S 40 . 
     In the exterior sheet bonding step S 50 , as shown in  FIG. 7  ( c ), a bonding region  22  is bonded by means of an adhesive agent in an overlap region  21  which is formed when both end parts  3 A and  3 B in the folding direction D 1  of the exterior sheet  3  are folded on each other. 
     In the packing product forming step S 60 , as shown in  FIG. 6  ( e ) and  FIG. 7  ( d ), the bonding region  3 C of the exterior sheet  3  is thermally bonded, whereby adhesive bonding treatment to partitioning the absorbent articles  10  on a one-by-one piece basis is made. By means of this step, packing units  2  for packing the absorbent articles  10  on a one-by-one piece basis are formed. 
     In a cutoff line part forming step S 70 , perforation forming process is performed at the partition unit  5 . By the perforation forming process, a cutoff line part  4  which is capable of individually cutting off the packing body  2  can be formed. The steps S 10  to S 70  described above are executed, whereby a continuous packing product  1  is completed. 
     As has been described above, according to the continuous packing product  1  of the embodiment, since the second resin layer  32  is formed by dissolving the thermoplastic resin forming the second resin layer  32  in a solvent and then applying the melted resin, the second resin layer  32  can be thinly formed in comparison with the first resin layer  31  which is a resin film. Therefore, heat of thermal bonding is easily transmitted to the first resin layer  31 , a heating time of thermal bonding is reduced, and productivity can be improved. Further, since transmission efficiency of the heat to the first resin layer is improved without increasing the heating temperature of thermal bonding, it is possible to prevent melting of the second resin layer  32  constituting the outside face  7 B of the exterior sheet  3  due to a rise of the heating temperature and then prevent the melted resin from adhering to a bonding jig. 
     As an example, melting points of the straight chain-like low-density polyethylene and low density polyethylene which form the first resin layer  31  are about 110 degrees Celsius, and a melting point of nylon forming the second resin layer  32  is about 160 degrees Celsius to 170 degrees Celsius, and since a difference in the melting points are 50 degrees Celsius or more, only the first resin layer  31  can be melted without melting the second resin layer  32  in a thermal bonding, and the sealing property of the first resin layer  31  can be maintained. 
     As has been described above, while the contents of the present invention were disclosed through the embodiment of the present invention, it should not be understood that the discussion and drawings forming a part of this disclosure limit the present invention. From this disclosure, a variety of alternative embodiments, examples, and operational techniques would be self-evident to one skilled in the art. 
     Exterior sheets according to exemplary modifications will be described with reference to  FIG. 8 .  FIGS. 7  ( a ) to ( d ) are a sectional view of the exterior sheet  3  according to exemplary modifications.  FIG. 7  ( a ) is an enlarged view showing a portion D shown in  FIG. 3  of the exterior sheet according to the embodiment above, and  FIGS. 7  ( b ) to ( d ) are enlarged sectional views of portions corresponding to the portion D in the exterior sheet  3  according to modifications. Like constituent elements of the embodiment in the exterior sheet  3  according to the exemplary modification are designated by like reference numerals, and a duplicate description is omitted. 
     As shown in  FIG. 7  ( a ), on the exterior sheet  3  according to the embodiment, the print layer  33  is laminated in a full region of the first resin layer  31 , and the second resin layer  32  is laminated in a full region of the print layer  33 . In this way, since the print layer  33  is laminated in the full region of the first resin layer  31 , a decorative effect due to characters or patters and the like of the print layer  33  can be attained in the full region of the exterior sheet  3 . 
     Further, the second resin layer  32  is laminated in the full region of the print layer  33 , whereby the print layer  33  can be protected by the second resin layer  32 . In order to visually recognize the print layer  33  from the outside of the packing unit  2 , it is desirable to configure the print layer  33  so as to be visually discernable from the side of the second resin layer  32  forming the outside face  7 B of the exterior sheet  3 . Specifically, the second resin layer  32  may be formed of a transparent or semitransparent material. 
     An exterior sheet  3 , as shown in  FIG. 7  ( b ), may be configured to have the first resin layer  31  and the second resin layer  32  without comprising the print layer  33 . With such a structure, since the step of forming print layer  33  is eliminated, productivity can be further improved, and reduction of production time and cost can be attained. 
     In an exterior sheet  3 , as shown in  FIG. 7  ( c ), the second resin layer  32  may be formed in only the bonded (partition) region  3 C. In the region  3 C, heat resistance processing is made by means of the second resin layer  32 , whereby, when thermal bonding is applied from the side of the second resin layer  32 , the first resin layer  31  can be protected by means of the second resin layer  32 . 
     While, in the exemplary modification shown in  FIG. 7  ( c ), the exterior sheet  3  is formed by means of the first resin layer  31  and the second resin layer  32 , a print layer may be formed between the first resin layer  31  and the second resin layer  32 , or alternatively, a print layer may be formed in the full region of the first resin layer  31 . 
     In a modification, as shown in  FIG. 7  ( d ), the print layers  33  are intermittently formed on the exterior sheet  3  and the print layers  33  need not be formed in the bonded region  3 C. In this way, the print layers  33  need not be formed in the bonded region  3 C, whereby the heat from the bonding jig can be easily transmitted to the first resin layer  31 . 
     Next, a packing unit according to an exemplary modification will be described with reference to  FIG. 9 .  FIG. 9  is a sectional view of the folding direction D 1  that is orthogonal to the continuous direction of the packing bodies  2  according to the exemplary modification. The exterior sheets  3  of the packing bodies  2  according to the exemplary modification are bonded with each other by means of thermal bonding while the first resin layer  31  and the first resin layer  31  are opposite to each other at both end parts  11 A and  11 B in the folding direction D 1 . In this way, these resin layers may be bonded with each other by means of thermal bonding, not only at the partition units  5  for partitioning the packing body  2  and the packing body  2  but also in a bonding region  22  in which both end pats in the folding direction D 1  of the exterior sheet  3  is to be bonded as well. 
     In addition, while, in the embodiment of the present invention, one absorbent article was housed in a packing unit, two or more absorbent articles may be configured so as to be housed in a packing unit. 
     Further, the absorbent article of the present invention may be a panty liner (a vaginal discharge sheet), an incontinent pad or the like other than the above absorbent article. 
     Thus, it is a mater f course that the present invention encompasses a variety of embodiments or the like, which are not described herein. Therefore, technical scope of the present invention is defined only by the specific matters of the invention according to the claims that are reasonable from the foregoing description. 
     Embodiments, and variations of any aspect of the invention, may be such that an absorbent article and exterior sheet in a packing unit are folded in at least a first direction which is orthogonal to the continuous direction of the packing product. 
     Embodiments may be such that the absorbent article and exterior sheet are also folded in the opposite direction to the first orthogonal direction to form an overlap region. 
     A method of manufacturing a continuous package may, in any aspect, include a step of folding the exterior sheet and the absorbent article along a direction which is orthogonal to a continuous direction in which the absorbent articles are continuous, and then, wrapping the absorbent article by means of the exterior sheet. 
     They may further include a step which the exterior sheet and absorbent article are also folded in a second orthogonal direction opposite to the first orthogonal direction to form an overlap portion. 
     The above features and steps may be used in any embodiments or aspects of the invention.