FOLHA DE EMBALAGEM, ARTIGO ABSORVENTE E MÉTODO DE PRODUÇÃO DE UMA FOLHA DE EMBALAGEM
Patent Information
- Authority / Receiving Office
- BR · BR
- Patent Type
- Applications
- Current Assignee / Owner
- DAIO PAPER CORP
- Filing Date
- 2023-11-10
- Publication Date
- 2026-08-04
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[001] The present invention relates to packing sheets, individually wrapped absorbent articles, each formed by the individually wrapped absorbent article with a packing sheet, and methods of producing packing sheets. BACKGROUND OF THE TECHNIQUE
[002] For reasons of hygiene during storage, convenience in transport and the like, many absorbent articles, such as sanitary napkins, panty liners, incontinence pads and the like, are supplied as individually wrapped absorbent articles (individual packs) in the state where an absorbent article is individually wrapped with a packing sheet and sealed.
[003] Such individually packaged absorbent article is transported in a state where an absorbent article is packaged with a packing sheet. Thus, it may often be preferable to print on a surface of the packing sheet so that the appearance of the individually packaged absorbent article is not apparent as an absorbent article at first glance.
[004] Patent Document 1 discloses an absorbent article package comprising an absorbent article and a packaging material that contains the absorbent article, and has a design pattern visible on the outside. DOCUMENTS OF THE RELATED TECHNIQUE PATENT DOCUMENTS
[005] Patent Document 1: International Publication No. WO2020 / 095764 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION
[006] In recent years, instead of conventional nonwoven fabrics or plastic films, the use of a paper material to form a packaging sheet has Petition 870250083727, dated 09 / 17 / 2025, pp. 74 / 108 2 / 24 has been promoted in view of environmental concerns. In the case where a packaging sheet is made of paper material, tearing of the packaging sheet, i.e., tearing of the paper, during printing or similar processes, needs to be avoided.
[007] The present invention was developed in view of the aforementioned problems existing in the related art, and one of the objectives of the present invention is to provide a packaging sheet that can prevent tearing when printing is performed on its surface, an individually packaged absorbent article formed by individually packaging an absorbent article with the packaging sheet, and a method for producing the packaging sheet. SOLUTION TO THE PROBLEM
[008] In order to achieve the above objective, the present invention is directed to a packaging sheet comprising paper. One surface of the packaging sheet is subjected to printing while the packaging sheet is carried in the direction of the packaging sheet's fiber, and the packaging sheet individually wraps an absorbent article. The tensile strength of the packaging sheet in the fiber direction is 16 N or more and 25 N or less. The packaging sheet satisfies 8.45 < X x (1 Y / 100), where X (N) is the tensile strength of the packaging sheet in the fiber direction before printing, and Y (%) is the proportion of the packaging sheet area to which a printing ink, a heat-sealing agent for adhering parts of the packaging sheets, or both are applied, relative to the total area of the packaging sheet.
[009] In the present invention with the above configuration, the tensile strength of the packaging sheet in the transport direction is 16 N or more and 25 N or less, and the tensile strength of the packaging sheet before printing and the ratio of the packaging sheet area to which a printing ink, a heat sealing agent, or both are applied in relation to the total area of the packaging sheet satisfy the above condition. Thus, tearing of the packaging sheet can be avoided when printing is performed on the surface of the packaging sheet.
[010] In addition, the packaging sheet can be configured so that the Petition 870250083727, dated 09 / 17 / 2025, pp. 75 / 108 3 / 24 The MMD (average coefficient of friction deviation) of the surface of the packaging sheet to be printed must be 0.050 or less.
[011] The packaging sheet with the above configuration allows uniform printing to be carried out on the surface of the packaging sheet, thus improving the appearance.
[012] In addition, the packaging sheet can be configured so that the basis weight of the packaging sheet paper is equal to or less than 30 g / m2.
[013] The packaging sheet with the above configuration can avoid problems such as increased material cost due to high paper grammage, and compromised operability and noise generated when opening due to high paper rigidity.
[014] Furthermore, an individually wrapped absorbent article may be configured so that it includes the wrapping sheet and an absorbent article individually wrapped with the wrapping sheet, wherein the wrapping sheet is folded and the edge portions of the folded wrapping sheet are sealed to individually wrap the absorbent article, and the seal strength of the edge portions is less than the tensile strength.
[015] In the individually packaged absorbent article with the above configuration, it is unlikely that the packaging sheet will tear when the sealed parts are peeled off to remove the absorbent article.
[016] Furthermore, a method of producing a packaging sheet is a method of producing a packaging sheet that individually wraps an absorbent article. The production method includes at least one of the following: a printing step on a surface of the packaging sheet while conveying the packaging sheet in the direction of the packaging sheet's fiber; and a step of applying a heat-sealing agent to the surface of the packaging sheet while conveying the packaging sheet in the direction of the fiber. The tensile strength of the packaging sheet in the fiber direction is 16 N or more and 25 N or less. The packaging sheet satisfies 8.45 < X χ (1 - Y / 100), where X (N) is the tensile strength. Petition 870250083727, dated 09 / 17 / 2025, pp. 76 / 108 4 / 24 of the packaging sheet in the grain direction before printing, and Y (%) is the proportion of the packaging sheet area to which a printing ink, a heat-sealing agent for adhering parts of the packaging sheets, or both are applied, relative to the total packaging sheet area. EFFECTS OF THE INVENTION
[017] According to the present invention, tearing of a packaging sheet can be avoided when printing is performed on a surface of the packaging sheet. BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1] Figure 1 is a plan view illustrating one embodiment of the individually packaged absorbent article of the present invention; [Figure 2] Figure 2 is a plan view of a developed state of the individually packaged absorbent article illustrated in Figure 1; [Figure 3] Figure 3 is a cross-sectional view taken along line II illustrated in Figure 1; [Figure 4] Figure 4 is an enlarged view of section II illustrated in Figure 1; [Figure 5] Figure 5 is a view to explain a printing method on the packaging sheet illustrated in Figures 1 to 3; and [Figure 6] Figure 6 is a view illustrating a detailed configuration of a printed surface of the packaging sheet illustrated in Figures 1 to 3. DESCRIPTION OF MODALITIES
[018] The embodiments of the present invention will be described with reference to the following drawings. In the drawings, the same reference number is assigned to the same constituent or corresponding component, unless otherwise indicated, and redundant description may be omitted. < GENERAL CONFIGURATION OF INDIVIDUALLY PACKAGED ABSORBENT ITEM >
[019] Figure 1 is a plan view illustrating one embodiment of the article. Petition 870250083727, dated 09 / 17 / 2025, pp. 77 / 108 5 / 24 individually wrapped absorbent of the present invention. Figure 2 is a plan view of a developed state of the individually wrapped absorbent article 100 illustrated in Figure 1, and illustrates a view from the inner surface of the packaging sheet 10 or the side of the absorbent article 1 facing the skin of a user. Furthermore, Figure 3 is a cross-sectional view made along line II illustrated in Figure 1.
[020] As illustrated in Figures 1 to 3, the present embodiment is an individually wrapped absorbent article 100 comprising a wrapping sheet 10 and an absorbent article 1 individually wrapped with the wrapping sheet 10. As illustrated in Figure 2, the wrapping sheet 10 has, for example, a narrow and long shape in an developed state, and has a longitudinal direction (vertical direction) D1 and a lateral direction (horizontal direction) D2 orthogonal to the longitudinal direction. Furthermore, the longitudinal direction D1 and the lateral direction D2 of the wrapping sheet 10 also correspond to a longitudinal direction and a lateral direction of the absorbent article 1, respectively. <ARTIGO ABSORVENTE>
[021] The absorbent article 1 to be packaged with the packaging sheet 10 is an article that has a shape suitable when used to cover an orifice for the discharge of a bodily fluid (menstrual blood, vaginal discharge, urine, etc.), for example, a flat, narrow, and long shape. Specific examples of absorbent article 1 include sanitary napkins, panty liners (sheets for vaginal discharge), absorbent pads for light incontinence, and the like. In this descriptive report, the description is given primarily based on an example where the absorbent article is a sanitary napkin.
[022] The absorbent article 1 includes, for example, a fluid-permeable top sheet 3, a fluid-impermeable back sheet (not shown) and an absorber 4 disposed between the top sheet 3 and the back sheet, as shown in Figure 2.
[023] As a backing sheet, a sheet with at least one water-protective property may be used, such as an olefin-based resin sheet or Petition 870250083727, dated 09 / 17 / 2025, pp. 78 / 108 6 / 24 similar. The olefin-based resin is like polyethylene, polypropylene, or similar. A laminated nonwoven fabric, in which a nonwoven fabric is laminated onto a sheet of polyethylene or similar, or a laminated sheet of nonwoven fabrics, in which a waterproof film is inserted between the nonwoven fabrics to ensure substantial impermeability to fluids, can be used as the backing sheet. Additionally, a moisture-permeable sheet can be used as the backing sheet.
[024] As for top sheet 3, a porous or non-porous nonwoven fabric, a porous plastic sheet or similar is suitablely used. As for the fibrous material constituting the nonwoven fabric, for example, one or more synthetic fibers such as olefin (e.g., polyethylene, polypropylene, etc.), polyester, polyamide and the like, recycled fibers such as rayon, cuprammonium rayon and the like, blended fibers of the aforementioned, and natural fibers such as cotton and the like, may be used.
[025] Absorbent 4 is not limited, provided that absorbent 4 is a material that can absorb and retain a body fluid. Absorbent 4 preferably includes cotton pulp and a water-absorbing polymer. As the water-absorbing polymer, a superabsorbent polymer powder (SAP), a superabsorbent fiber (SAF), or a combination of the foregoing may be used. Examples of pulp include chemical pulp obtained from wood, cellulose fibers such as dissolving pulp, artificial cellulose fibers such as rayon, acetate, and the like. The pulp may be hardwood pulp obtained from hardwood, softwood pulp obtained from softwood, or a mixture of the foregoing pulp. In addition, the pulp may be recycled pulp that is recycled from used pulp.
[026] The length of absorber 4 can be from 0.5 mm to 25 mm. Absorber 4 can be configured so that a region corresponding to a body fluid discharge orifice (body fluid discharge orifice region) or a region facing the intergluteal cleft behind the body fluid discharge orifice region is convex. The absorber Petition 870250083727, dated 09 / 17 / 2025, pp. 79 / 108 7 / 24 has a size and shape that does not exceed the top sheet 3 and the back sheet. At the front and rear edges of the absorber, the outer edges of the back sheet and the outer edges of the top sheet 3 are joined, respectively, by an adhesive, such as a hot melt adhesive or similar, or by an adhesion method, such as heat sealing or ultrasonic sealing.
[027] As illustrated in Figure 2, the side sheets 7 can be provided respectively on the outer sides of the absorber 4 along the longitudinal direction D1 on both edge parts of the absorber 4 in the lateral direction D2. As side sheets 7, water-repellent nonwoven fabrics or hydrophilic nonwoven fabrics can be used.
[028] Note that absorbent article 1 is of the so-called wingless type which does not have wings in the example illustrated in Figures 1 to 3, but the absorbent article can be configured as an article with wings, each extending to the side. The wings can be formed by joining the side sheet and the back sheet.
[029] In addition, a non-slip adhesive part may be provided on the back sheet side of the absorbent article 1 (the side not in contact with the skin, i.e., the side facing the underwear when worn). The non-slip adhesive part is provided to prevent the absorbent item 1 from being displaced from the underwear when the absorbent item 1 is attached to the underwear. The non-slip adhesive portion is, for example, formed in several strips extending in the longitudinal direction D1 or in the lateral direction D2.
[030] The total length of the absorbent article 1 can be from 140 mm to 430 mm, and the width of the absorbent article 1 (the width of the main body excluding the flaps, if any) can be from 40 mm to 130 mm. <FOLHA DE EMBALAGEM>
[031] The packaging sheet 10 of this embodiment includes paper. The use of packaging sheet 10 made of paper can contribute to reducing the use of plastics and to achieving the sustainable development goals. In addition, paper can provide unique textures, such as the appearance and feel that give impressions. Petition 870250083727, dated 09 / 17 / 2025, pages 80 / 108 8 / 24 softness that natural materials have.
[032] The packaging sheet 10 includes cellulose fibers in an amount of % or more, and a design print is applied to an exposed surface of the packaging sheet that is exposed in a state where the absorbent article 1 is individually packaged with the packaging sheet. The detailed conditions of the packaging sheet 10 will be described later.
[033] The size of the packaging sheet 10 depends on the size or shape of an absorbent article 1 to be packaged. For example, a length in the longitudinal direction D1 (may simply be referred to as length) may vary from 100 mm to 450 mm, and a length in the lateral direction D2 (may simply be referred to as width) may vary from 70 mm to 250 mm in the state in which the packaging sheet 10 is fully extended (the unfolded state). In the illustrated example, the packaging sheet 10 has a rectangular shape in an unfolded state, but it may have, for example, an oblong shape. < PACKAGE CONFIGURATION FOR INDIVIDUALLY WRAPPED ABSORBENT ITEM >
[034] As illustrated in Figures 1 to 3, the absorbent article 1 is packaged by being folded together with the packaging sheet 10, thus forming an individually packaged absorbent article 100. At the time of folding, first, the absorbent article 1 is placed on the inner surface of the packaging sheet 10 so that the back side of the absorbent article 1 faces the inner surface of the packaging sheet 10, as illustrated in Figure 2. Then, the packaging sheet 10 and the absorbent article 1 are folded together in the longitudinal direction D1 on the first fold line F1 and on the second fold line F2 along the width direction D2.More specifically, a first region R1, including one end 11 of the packaging sheet 10 in the longitudinal direction D1, is folded in the longitudinal direction D1 along the first fold line F1, and a second region R2, including the other end 12 of the packaging sheet 10 in the longitudinal direction D1, is folded along the second fold line F2. A region of the sheet of... Petition 870250083727, dated 09 / 17 / 2025, pp. 81 / 108 9 / 24 Packaging 10 between the first region R1 and the second region R2 is a third region R3. In the illustrated example, packaging sheet 10 is folded so that the second region R2 is folded first, and then the first region R1 is folded to overlap the outer surface of the second region R2 (Figures 1 and 2), but the folding order of the first region R1 and the second region R2 can be reversed. After packaging sheet 10 and absorbent article 1 are folded together in three (triple fold inwards) to enclose absorbent article 1, both edge parts in the lateral direction D2 are sealed along the longitudinal direction D1, thus forming sealed portions 15.
[035] This three-fold or more packaging form can be formed relatively simply and can hygienically enclose an absorbent article 1. In addition, the absorbent article 1 can be easily removed. Note that the folding form is not limited to three folds and can be four folds or more, or it can be two folds. <PORÇÃO VEDADA>
[036] As illustrated in Figure 1, the individually packaged portions of the absorbent article 100, where the absorbent article 1 is not present on both edges in the lateral direction D2, are respectively sealed, thus forming sealed portions 15. In the present embodiment, the sealed portions 15 are formed by applying a thermal sealing agent to the surface of the packaging sheet 10 to be sealed, then passing the packaging sheet 10 between a pair of heated rollers to press together the overlapping portions of the folded packaging sheet 10 in the thickness direction.
[037] As illustrated in Figure 1, the sealed portions 15 are formed, for example, along the entire length of the individually packaged absorbent article 100 in the longitudinal direction D1. This is preferable from the point of view that the erroneous entry of dust or dirt, or of a finger or a small object through the end edges in the lateral direction can be avoided (the seal is guaranteed).
[038] A side direction strip D2 in which each sealed part 15 is provided Petition 870250083727, dated 09 / 17 / 2025, pp. 82 / 108 10 / 24 is, for example, a 20 mm strip from the end edge in the lateral direction D2. The sealed portion 15 can be formed along the entire strip, or it can be formed in part of the aforementioned strip, for example, at a position away from the end edge in the lateral direction D2. The length (width) of each sealed portion 15 itself in the lateral direction D2 is preferably from 3 mm to 15 mm.
[039] Figure 4 is an enlarged view of section II illustrated in Figure 1 and illustrates a part that includes the sealed portion 15.
[040] As illustrated in Figure 4, the sealed portion 15 includes several press-bonded portions (or bonded portions) 15a that are separated from each other in a plan view. Each press-bonded portion 15a is a portion in which the overlapping portions of the folded packaging sheet 10 are joined by press-bonding. In the illustrated example, a portion beyond the press-bonded portions 15a is an unbonded portion in which the overlapping portions of the folded packaging sheet 10 are not bonded to each other. Since the press-bonded portions 15a are spread from each other, as described above, the bonded portions of the packaging sheet can be easily removed at the time of opening, and the opening capability can be improved, for example, compared to a case where the portions of the packaging sheets 10 are bonded across the entire surface of the sealed part 15.In addition, this can prevent both edges of the individually wrapped absorbent material from becoming excessively hard and affecting the texture.
[041] Note that the shape of each press-jointed portion 15a in a plan view is a square in the example illustrated in Figure 4, but the shape is not limited to the illustrated shape and may be, for example, a quadrilateral other than a square, such as a rectangle or a parallelogram, a polygon other than a quadrilateral, a circle, an ellipse, a heart shape, a star shape, a teardrop shape, or something similar. Furthermore, the size of each press-jointed portion 15a is, for example, a square with a side of 0.25 mm to 2.5 mm or an equivalent size with the same area as the square. In addition, an arrangement of Petition 870250083727, dated 09 / 17 / 2025, pp. 83 / 108 11 / 24 portions connected by pressure 15a can be a lattice pattern, as illustrated in Figure 4, or it can be a stepped pattern. (FASTENING TAPE)
[042] As illustrated in Figures 1 to 3, the individually packaged absorbent article 100 may be provided with a fastening tape 30 in the center of the lateral direction D2, near the end edge (one end 11 of the packaging sheet 10). As illustrated in Figure 1, the fastening tape 30 may be provided over the first region R1 and the second region R2 passing through one end 11 of the packaging sheet 10. The fastening tape 30 includes a proximal portion 31 bonded to the first region R1 and a tip portion 32 bonded to the second region R2 in a plan view.
[043] As fastening tape 30 is provided, the user can hold the fastening tape 30 (more specifically, the tip part 32 of the fastening tape 30) to lift and pull the first region R1 at the time of opening the individually wrapped absorbent article 100, so that opening the individually wrapped absorbent article 100 is further facilitated. In addition, when an absorbent article is replaced, the presence of the fastening tape 30 makes it possible to wrap a used absorbent article with a packing sheet obtained from a newly opened and individually wrapped absorbent article, and to secure the end of the packing sheet with another part of the packing sheet. This can prevent the used absorbent article from being exposed due to the opening of the packing sheet and can dispose of the used absorbent article hygienically.
[044] The width (length in the lateral direction D2) of the fastening tape 30 can preferably be from 5 mm to 30 mm and, more preferably, from 10 mm to 20 mm. In addition, the total length of the fastening tape 30 can preferably be from 10 mm to 50 mm and, more preferably, from 15 mm to 40 mm. < STRENGTH OF THE PACKAGING SHEET AND PROPORTION OF THE APPLIED INK AREA >
[045] When the absorbent article 100 individually packaged is configured Petition 870250083727, dated 09 / 17 / 2025, pp. 84 / 108 12 / 24 as described above is produced, first, the printing is done on the packaging sheet 10.
[046] Figure 5 is a view to explain a printing method on the packaging sheet 10 illustrated in Figures 1 to 3.
[047] When the packaging sheet 10 illustrated in Figure 1 is produced, as illustrated in Figure 5, in a printing step, printing is performed on the surfaces of several packaging sheets 10 in a state where the packaging sheets 10 are arranged close to each other in a fiber direction (machine direction (MD)) which is a lateral direction. At this time, printing is performed while the packaging sheets 10 are transported in the lateral direction as a transport direction A. However, if the tensile strength of the packaging sheet 10 is weak, the packaging sheet is torn during printing or something similar, i.e., the paper tears.
[048] Furthermore, when printing is performed on the packaging sheet 10, the ink used for printing permeates the packaging sheet 10, which loosens the fibrous tissues and weakens the bond between the fibers. This also reduces tensile strength, causing tears in the paper. The above phenomenon occurs not only with the printing ink. Even when the printing step is not provided, the above phenomenon also occurs due to the application of a thermal sealing agent in an application step in which the thermal sealing agent is applied to the packaging sheet 10 to seal the overlapping parts of the folded packaging sheet 10.
[049] Figure 6 includes views illustrating an example of printing performed on the packaging sheet 10 illustrated in Figures 1 to 3, where (a) is a plan view of the individually packaged absorbent article and (b) is an enlarged view of section B in the case of dot printing.
[050] When printing is carried out on the packaging sheet 10, as illustrated in Figure 6(a), there is a colored region 41 that is colored by the printing and an uncolored region 42 that is not printed. In the case of so-called solid printing carried out by photogravure, an ink is applied to the entire area of each region. Petition 870250083727, dated 09 / 17 / 2025, pages 85 / 108 13 / 24 colored 41. Thus, the proportion of an area to which the ink is applied in relation to the total area of the packaging sheet 10 is determined by: (total area of colored regions 41) / (total area of packaging sheet 10).
[051] On the other hand, in the case where printing is done by dot printing, as illustrated in Figure 6(b), there are applied regions 41a to which ink is applied, and a non-applied region 41b to which no ink is applied within each colored region 41 where printing is done. Thus, the relationship between the area to which the ink is applied and the entire area of the packaging sheet 10 is determined by: (total area of the applied regions 41a) / {(area of the uncolored region 42) + (total area of the unapplied regions 41b)}.
[052] That is, in dot printing, the proportion of the area to which the ink is applied in relation to the total area of the packaging sheet 10 can be defined to not be 100%, even when the entire area of the packaging sheet 10 is subject to printing.
[053] Therefore, various types of paper considered usable as packaging sheet 10 were examined for printability based on tensile strength and the ratio of the area to which the ink or thermal sealing agent is applied to the total area of the packaging sheet 10. As printing was performed on the packaging sheet 10 of the present embodiment while the packaging sheet 10 was transported in the direction of the paper fibers, the tensile strength of the packaging sheet 10 in the direction of the fibers was measured. In this examination, the measurement was performed at room temperature using a tensile tester, Tensilon. According to the measurement conditions, a paper base material to be a packaging sheet 10 was cut into an individual piece with a size of 120 mm in the direction of the fiber and 25 mm in the direction orthogonal to the direction of the fiber, and the tensile strength was measured by pulling the piece in the direction of the fiber at a speed of 500 mm / sec.The spacing between the chucks was set at 50 mm. [TABLE 1] Petition 870250083727, dated 09 / 17 / 2025, pages 86 / 108 14 / 24 Sample Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Comparative Ex. 1 Comparative Ex. 2 Comparative Ex. 3 Comparative Ex. 4 Comparative Ex. 5 Paper type base weight Unryushi 14 g / m2 Unryushi 14 g / m2 Crepe paper 18 g / m2 Crepe paper 18 g / m2 Crepe paper 18 g / m2 Unryushi 17 g / m2 Rayon PM 14 g / m2 Unryushi 25 g / m2 Kin Shachihoko 24.4 g / m2 Kin Shachihoko 30 g / m2 Tensile strength in MD (N) 16.9 16.9 17.7 17.7 17.7 25.7 26.8 53.9 38.6 30 Usability AAAAAAACBC Operability of Printout AACAABA - AA Thermal sealing agent area ratio 0 50 100 0 0 100 100 Not performed 100 100 Petition 870250083727, dated 09 / 17 / 2025, pages 87 / 108 15 / 24 Sample Ex. 1 Ex. 2 Ex. 3 Ex. 4 (%) Ink area ratio (%) 20 0 0 12 Ex. 5 Comparative Ex. 1 Comparative Ex. 2 Comparative Ex. 3 Comparative Ex. 4 Comparative Ex. 5 35 72 72 Not performed 72 72 Petition 870250083727, dated 09 / 17 / 2025, pages 88 / 108 16 / 24
[054] As shown in Table 1, as Example 1, a packaging sheet 10 made of Unryu-shi (produced by Marubishi Paper Tec. Corporation) with a basis weight of 14 g / m2, which was not coated with a thermal sealing agent and had an applied ink area ratio of 20% relative to the entire area of the packaging sheet 10, was used. As Example 2, a packaging sheet 10 made of Unryu-shi (produced by Marubishi Paper Tec. Corporation) with a basis weight of 14 g / m2, which was not coated with ink, and had an applied thermal sealing agent area ratio of 50% relative to the entire area of the packaging sheet 10, was used. As Example 3, a packaging sheet 10 made of crepe paper (produced by Daio Paper Corporation) with a basis weight of 18 g / m2 was used, which was not coated with ink and had an applied area ratio of thermal sealant of 100% in relation to the entire area of the packaging sheet 10.Example 4: A packaging sheet 10 made of crepe paper (produced by Daio Paper Corporation) with a basis weight of 18 g / m² was used, which was not coated with a thermal sealing agent, and an ink application area ratio of 12% relative to the entire area of the packaging sheet 10. Example 5: A packaging sheet 10 made of crepe paper (produced by Daio Paper Corporation) with a basis weight of 18 g / m² was used, which was not coated with a thermal sealing agent, and an ink application area ratio of 35% relative to the entire area of the packaging sheet 10. Comparative Example 1: A packaging sheet 10 made of Unryu-shi (produced by Marubishi Paper Tec. Corporation) with a basis weight of 17 g / m², which had a thermal sealing agent application area of 100% relative to the entire area of the packaging sheet 10, and an applied paint area ratio of 72% in relation to the entire area of the packaging sheet 10 was used.As a Comparative Example 2, a packaging sheet 10 made of Rayon PM (produced by Marubishi Paper Tec. Corporation) with a basis weight of 14 g / m2, which had an applied area of thermal sealing agent of 100% in relation to the entire area of the packaging sheet 10, and an applied area proportion of ink of 72%. Petition 870250083727, dated 09 / 17 / 2025, pages 89 / 108 17 / 24 in relation to the entire area of the packaging sheet 10, was used. As a Comparative Example 3, Unryu-shi (produced by Marubishi Paper Tec. Corporation) with a basis weight of 25 g / m2 was used. As Comparative Example 4, a packaging sheet 10 made of Kin Shachihoko paper (produced by Daio Paper Corporation) with a basis weight of 24.4 g / m2 was used, which had a thermal sealant application area ratio of 100% in relation to the entire area of the packaging sheet 10, and an ink application area ratio of 72% in relation to the entire area of the packaging sheet 10. As Comparative Example 5, a packaging sheet 10 made of Kin Shachihoko paper (produced by Daio Paper Corporation) with a basis weight of 30 g / m2 was used, which had a thermal sealant application area ratio of 100% in relation to the entire area of the packaging sheet 10, and an ink application area ratio of 72% in relation to the total area of the packaging sheet 10.Note that Rayon PM is a paper composed of 15% rayon and 85% cellulose.
[055] In Table 1, regarding print operability, A is assigned to the case where printing could be performed without tearing the paper, and C is assigned to the case where the paper was torn and printing could not be performed. Furthermore, in terms of usability, it was determined whether or not there was a problem in use, such as the edges of an individual package becoming sharp or a rustling sound being generated due to the paper stiffening. Then, A is assigned to the case where there was no usability problem, C is assigned to the case where an individual package is stiff and the sound is generated during use, and B is assigned to the case where there was a problem with either stiffness or sound.
[056] As a result, in Comparative Examples 3 and 5, the edges of the individual package became sharp, and a perceptible rustling sound was generated during use. It was found from the above results that the edges of the individual package become sharp and a perceptible rustling sound is generated during use when the tensile strength of the packaging sheet is greater than 54 N. In addition, tearing of the paper occurred during printing on paper with a tensile strength of 17.7 N. Petition 870250083727, dated 09 / 17 / 2025, pp. 90 / 108 18 / 24 used in Examples 3 to 5. On the other hand, no paper tearing occurred in Comparative Example 1 using paper with a tensile strength of 25.7 N. It was verified from the results above that paper tearing can occur during printing when the tensile strength of the packaging sheet is 25 N or less.
[057] Therefore, the proportion of the area where the ink or thermal sealant was applied in relation to the total area of the packaging sheet 10 was checked for the packaging sheet with a tensile strength of 25 N or less. As a result, paper tearing occurred during printing in Example 3, in which the packaging sheet made of paper with a tensile strength of 17.7 N had a thermal sealant applied area ratio of 100% in relation to the entire area of the packaging sheet 10. On the other hand, paper tearing did not occur during printing in Example 5, in which the packaging sheet made of paper with a tensile strength of 17.7 N had a proportion of ink applied area of 35% in relation to the entire area of the packaging sheet 10.
[058] Furthermore, the paper tear did not occur during printing in Example 2, in which the packaging sheet made of paper with a tensile strength of 16.9 N had a thermal sealing area application rate of 50% in relation to the entire area of the packaging sheet 10 of the ink.
[059] Here, the proportion of the ink application area that allows printing is relatively large in relation to the paper's strength. Specifically, as the tensile strength of the paper increases, the proportion of the ink application area that allows printing increases. Therefore, the limit value to allow printing, which is determined by (tensile strength) χ (1 - proportion of the area to which the ink (heat sealing agent) is applied), is a constant value.
[060] Therefore, based on the results above, for the paper used in the Example 2, which had the lowest tensile strength among the paper types examined above, the applied thermal sealing area ratio of 50%, at which the print operability was A, was assigned in the formula above, and 16.9 N was assigned as the tensile strength, thus leading to the value, which is 16.9 χ (1 - 0.50) = 8.45. In Petition 870250083727, dated 09 / 17 / 2025, pp. 91 / 108 19 / 24 then, this value is defined as the lower limit so that paper tearing does not occur during printing.
[061] Thus, it was found that a packaging sheet that satisfies the relationship of 8.45 < X χ (1 - Y / 100) does not cause paper tearing during printing, where X (N) is the tensile strength and Y (%) is the proportion of the area to which the ink, the heat sealing agent, or both are applied relative to the total area of the packaging sheet. Note that the above formula holds in any of the cases where any of the values, with which the print operability was A, is assigned to the algebra of X and Y.
[062] Note that Unryu-shi, Rayon PM, and Kin Shachihoko had print operability even when the area ratio of the heat sealing agent was 100%. Therefore, restriction of the applied area is not necessary for paper with tensile strength greater than 25 N. Furthermore, paper with tensile strength less than 16 N has insufficient print operability regardless of the area ratio of the applied ink or heat sealing agent, and is likely to cause breakage of an individual package during opening.
[063] It was found from the above results that, when the packaging sheet 10 has a tensile strength of 16 N or more and 25 N or less in the transport direction during printing, and satisfies 8.45 < X χ (1 - Y / 100), where X (N) is the tensile strength before printing, and Y (%) is the ratio of the area for which printing ink or thermal sealing agent is used to adhere the overlapping portions of the folded packaging sheet to the total area of the packaging sheet 10, tearing can be avoided when printing is performed on the surface of the packaging sheet. In addition, it is also possible to prevent the edges of the individual packaging from becoming sharp and generating a perceptible rustling sound during use.
[064] Thus, it is possible to supply an individually packaged absorbent article 100 using the packaging sheet 10 made of paper, which can be printed using thin paper as packaging sheet 10 and has high capacity Petition 870250083727, dated 09 / 17 / 2025, pp. 92 / 108 20 / 24 design, ensuring operability and usability.
[065] In this case, if the surface of the packaging sheet 10 is rough, the printing is not carried out uniformly, which impairs the appearance. Therefore, an experiment to determine if the printability was high was carried out by measuring the MMD (deviation from the mean value of the coefficient of friction), which is an index that indicates the smoothness of the paper surface. As a result, it was found that the paper had printability when the paper surface had an MMD of 0.050 or less before printing, and the use of this paper allowed printing to be carried out on the packaging sheet 10, thus improving the design.
[066] In addition, if the paper weight is high, the cost of the material increases. Furthermore, the paper's rigidity is increased, which causes problems such as poor operability and noise during opening. Therefore, the paper weight should preferably be equal to or less than 30 g / m2. <FORÇA DA PORÇÃO VEDADA>
[067] As described above, in the individually packaged absorbent article 100, the sealed portions 15 are formed by folding the packaging sheet 10 together with the absorbent article 1 in three (triple fold inwards) to enclose the absorbent article 1, and sealing both edges of the folded packaging sheet 10 in the lateral direction D2 along the longitudinal direction D1. Then, the sealed portions 15 joining the overlapping parts of the folded packaging sheet 10 are removed, so that the individually packaged absorbent article 100 is opened and the absorbent article 1 is removed.
[068] If the sealing resistance of the sealed portions 15 is high, the packaging sheet 10 may be torn when the sealed portions 15 joining the overlapping parts of the folded packaging sheet 10 are separated to remove the absorbent article 1.
[069] Therefore, a relationship between tensile strength and sealing strength of the sealed part was examined for the configuration in which the packing sheet 10 was not torn when the overlapping parts of the folded packing sheet 10 Petition 870250083727, dated 09 / 17 / 2025, pp. 93 / 108 21 / 24 were detached. In this examination, the measurement was performed at room temperature using a Tensilon tensile tester. According to the measurement conditions, packaging sheet 10 was cut into a 25 mm wide piece to include the sealed portion 15 (6 mm sealing width) in the longitudinal direction of the packaging sheet, and the tensile strength was measured by pulling the sealed portion of the cut sample in the longitudinal direction of packaging sheet 10. For the measurement, the pulling speed was set at 100 mm / s, and the gap between the mandrels was set at 10 mm. The maximum point load (N / measured width) was determined as the strength of the sealed portion 15. [TABLE 2] Petition 870250083727, dated 09 / 17 / 2025, pp. 94 / 108 22 / 24 Sample Ex. 1 Comparative Ex. 1 Comparative Ex. 2 Paper Type Crepe Paper Unryu-shi Rayon PM Base Weight 18 g / m2 17 g / m2 14 g / m2 Tensile Strength after Printing (N / mm) on MD 0.60 1.55 1.11 on CD 0.19 0.39 0.32 Sealing Strength of Individual Package (N / mm) 0.03 0.06 0.04 Petition 870250083727, dated 09 / 17 / 2025, pages 95 / 108 23 / 24
[070] As shown in Table 2, crepe paper (produced by Daio Paper (produced by Marubishi Paper Tec. Corporation) with a basis weight of 18 g / m2 was used as Example 1. As Comparative Example 1, Unryu-shi (produced by Marubishi Paper Tec. Corporation) with a basis weight of 17 g / m2 was used. As Comparative Example 2, Rayon PM (produced by Marubishi Paper Tec. Corporation) with a basis weight of 14 g / m2 was used. As a result of examining the above paper, the paper from Example 1 and the paper from Comparative Examples 1 and 2 had a sealing strength of the sealed part 15 that was lower than the tensile strength of the packaging sheet 10.
[071] It has been verified from the above that, if the sealing strength of the sealed part 15 is less than the tensile strength of the packaging sheet 10, it is unlikely that the packaging sheet 10 will be torn when the sealed parts 15 that join the overlapping parts of the folded packaging sheet 10 are removed to remove the absorbent article 1.
[072] Although the present invention has been described through the embodiments above, the present invention is not limited to the embodiments above. The embodiments above may be altered by means of changes, modifications, substitutions, additions, deletions, combinations or the like in various ways within the scope described in the claims, and such embodiments also belong to the technical scope of the present invention. Furthermore, the constituent components described above may be combined arbitrarily.
[073] This international application claims priority based on Japanese patent application no. 2023-055944, filed on March 30, 2023, the full content of which is incorporated herein by reference. DESCRIPTION OF NUMERICAL REFERENCES absorbent article top sheet absorbent side sheet packaging sheet Petition 870250083727, dated 09 / 17 / 2025, pp. 96 / 108 24 / 24 one end in the longitudinal direction the other end in the longitudinal direction sealed portion pressure-bonded portion fixation tape proximal portion tip portion colored region 41st applied region 41b region not applied region not colored 100 individually wrapped absorbent items D1 longitudinal direction of packaging sheet D2 side direction of packaging sheet F1 first fold line F2 second fold line R1 first region R2 second region R3 third region
Claims
1. Packaging sheet characterized by comprising: paper, wherein one surface of the packaging sheet is subjected to printing while the packaging sheet is carried in the direction of the packaging sheet's fiber, and the packaging sheet individually wraps an absorbent article, wherein the tensile strength of the packaging sheet in the fiber direction is 16 N or more and 25 N or less, and wherein the packaging sheet satisfies: 8.45 < X x (1 - Y / 100), wherein X (N) is the tensile strength of the packaging sheet in the fiber direction before printing, and Y (%) is the proportion of the packaging sheet area to which a printing ink, a heat-sealing agent for adhering parts of the packaging sheets, or both are applied, relative to the total packaging sheet area.
2. Packaging sheet, according to claim 1, characterized in that the MMD of the surface of the packaging sheet to be printed is 0.050 or less.
3. Packaging sheet, according to claim 1 or 2, characterized in that the grammage of the packaging sheet is equal to or less than 30 g / m2.
4. Individually packaged absorbent article, characterized by comprising: the packaging sheet, as defined in claim 1 or 2; and an individually packaged absorbent article with the packaging sheet, wherein the packaging sheet is configured such that the packaging sheet is folded and the edge portions of the folded packaging sheet are sealed to individually package the absorbent article, and Petition 870250083727, dated 09 / 17 / 2025, pp. 98 / 108 2 / 2 wherein the sealing strength of the edge portions is less than the tensile strength.
5. A method for producing a packaging sheet that individually packages an absorbent article, wherein the production method is characterized by comprising at least one of the following: a printing step on a surface of the packaging sheet while conveying the packaging sheet in the direction of the fiber; and a step for applying a heat-sealing agent to the surface of the packaging sheet while conveying the packaging sheet in the direction of the fiber, wherein the tensile strength of the packaging sheet in the direction of the fiber is 16 N or more and 25 N or less, and wherein the packaging sheet satisfies: 8.45 < X x (1 - Y / 100), wherein X (N) is the tensile strength of the packaging sheet in the direction of the fiber before printing, and Y (%) is the proportion of the area of the packaging sheet to which a printing ink, a heat-sealing agent for adhering parts of the packaging sheets, or both are applied, relative to the total area of the packaging sheet.