Method for manufacturing individually packaged absorbent article, and individually packaged absorbent article

Abstract

A method for manufacturing an individually packaged absorbent article including a paper packaging sheet and an absorbent article individually packaged by the paper packaging sheet includes placing the absorbent article on an inner surface of a long packaging sheet body, which is the paper packaging sheet, with a space therebetween in a transport direction, and placing the absorbent article on the inner surface of the long packaging sheet body, which is the paper packaging sheet. The packaging sheet long bodies are folded together with the absorbent article in a direction perpendicular to the transport direction, and the packaging sheet long bodies are pressed together in the thickness direction by a pair of heated rollers at positions between the absorbent articles, and the temperature of at least one of the rollers is 110-180 DEG C.

Description

Technical Field

[0001] The present invention relates to a method for producing an individually packaged absorbent article and the individually packaged absorbent article. Background Art

[0002] Generally, absorbent articles such as sanitary napkins, panty liners, and incontinence pads are provided as individually packaged absorbent articles (individual packages) in a state of being individually packaged with a packaging sheet for reasons such as ensuring hygiene during storage and improving convenience during carrying.

[0003] In the manufacture of such individually packaged absorbent articles, absorbent articles are intermittently placed on a long strip of packaging sheet being conveyed, the long strip of packaging sheet together with the absorbent articles are folded inwardly into three parts in a direction perpendicular to the conveying direction, and then the long strip of packaging sheet is heat-pressed by two rollers arranged facing each other at a position where there are no absorbent articles to form a sealing portion (for example, refer to patent document 1).

[0004] [Prior art literature]

[0005] [Patent Literature]

[0006] [Patent Document 1] Patent No. 4275105 Summary of the invention

[0007] [Problems to be solved by the invention]

[0008] As packaging sheets for individually packaged absorbent articles, the materials actually used are basically resin films and nonwoven fabrics, which are sheets made of these plastic materials. Therefore, when forming the seals at both edges of the short side direction of the individually packaged absorbent articles, the packaging sheet materials can be fused together by heat, so that the necessary sealing strength can be easily ensured.

[0009] In response to this, in recent years, paper packaging sheets have been put into practical use from the perspective of reducing plastics. Paper does not melt even when heated under normal conditions, so in the manufacture of individually packaged absorbent articles containing paper packaging sheets, the sealing of the two edges is formed by bonding the packaging sheets physically meshing with each other or using adhesives. Such a sealing method requires the preparation of a device that is different from the existing device, which costs manufacturing effort and cost.

[0010] In view of the above, an object of one embodiment of the present invention is to form sealed portions at both edges of an individually wrapped absorbent article with appropriate strength without consuming much effort and cost in a method for manufacturing an individually wrapped absorbent article formed of a paper packaging sheet.

[0011]

Methods to solve the problem

[0012] One embodiment of the present invention is a method for manufacturing individually packaged absorbent articles comprising a paper packaging sheet and absorbent articles individually packaged by the packaging sheet, comprising: placing absorbent articles at intervals in a conveying direction on the inner surface of a long strip of packaging sheet serving as the paper packaging sheet, folding the long strip of packaging sheet together with the absorbent articles in a vertical direction perpendicular to the conveying direction, and pressing the long strips of packaging sheet together in a thickness direction at a position between the absorbent articles by a pair of heated rollers, wherein the temperature of at least one of the rollers is 110 to 180°C.

[0013] [Effects of the Invention]

[0014] According to one aspect of the present invention, in a method for manufacturing an individually wrapped absorbent article formed of a paper packaging sheet, it is possible to form sealed portions at both edges of the individually wrapped absorbent article with sufficient strength without consuming much effort and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015]

Figure 1

[0016]

Figure 2

[0017]

Figure 3

[0018]

Figure 4

[0019]

Figure 5

[0020]

Figure 6

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each of the drawings, the same or corresponding structures may be given the same reference numerals and the description thereof may be omitted unless otherwise specified.

[0022] <Basic structure of individually packaged absorbent articles>

[0023] First, the basic structure of the individually packaged absorbent article will be described. Figure 1 A plan view of an individually packaged absorbent article 100 is given in FIG. Figure 2 In the given Figure 1 The plan view of the individually packaged absorbent article in the unfolded state is a view observed from the inner surface of the packaging sheet 10 or from the skin side of the absorbent article 1. Figure 3 Given in Figure 1 II line cross section.

[0024] like Figure 1 to Figure 3 As shown, the individually packaged absorbent article 100 comprises a packaging sheet 10 and an absorbent article 1 individually packaged by the packaging sheet 10. Figure 2 As shown, the packaging sheet 10 can be an elongated shape in the unfolded state, having a long side direction (longitudinal direction) D1 and a short side direction (transverse direction) D2 perpendicular to the long side direction. In addition, the long side direction D1 and the short side direction D2 of the packaging sheet 10 correspond to the long side direction and the short side direction of the absorbent article 1, respectively.

[0025] (Absorbent articles)

[0026] The absorbent article 1 packaged by the packaging sheet 10 may be a flat and elongated article to be worn facing the discharge outlet of body fluids (menstrual blood, vaginal discharge, urine, etc.). Specific examples of the absorbent article 1 may be sanitary napkins, panty liners (pudendal discharge sheets), and panty liners for light incontinence.

[0027] Absorbent article 1 such as Figure 2 As shown, the structure may include a liquid-permeable top sheet 3, a liquid-impermeable back sheet (not shown), and an absorbent body 4 disposed between the top sheet 3 and the back sheet.

[0028] As the back sheet, a sheet having at least water-blocking properties, such as an olefin resin sheet such as polyethylene or polypropylene, can be used. A laminated nonwoven fabric obtained by laminating a nonwoven fabric on a polyethylene sheet or the like, or a laminated sheet obtained by ensuring substantial liquid-impermeability of a nonwoven fabric through a waterproof film, etc. can be used. In addition, a sheet having moisture permeability can be used.

[0029] As the top sheet 3, it is suitable to use a porous or non-porous nonwoven fabric, a porous plastic sheet, etc. As the material fiber constituting the nonwoven fabric, for example, olefins such as polyethylene and polypropylene, synthetic fibers such as polyester and polyamide, regenerated fibers such as rayon and cuprammonium yarn and their blended fibers, and natural fibers such as cotton can be used alone or in combination of two or more.

[0030] The absorbent body 4 is not limited as long as it is a material that can absorb and retain body fluids, but preferably contains cotton pulp and absorbent polymers. As absorbent polymers, superabsorbent polymer granular powder (superabsorbent polymer (SAP)), superabsorbent polymer fiber (superabsorbent fiber (SAF)) or a combination thereof can be used. As pulp, cellulose fibers such as chemical pulp and dissolving pulp obtained from wood, artificial cellulose fibers such as rayon and acetate can be cited. As pulp, hardwood pulp obtained from hardwood, softwood pulp obtained from softwood or mixed pulp thereof can be cited. In addition, the pulp can be recycled pulp regenerated from used pulp.

[0031] The thickness of the absorbent body 4 may be 0.5 to 25 mm. The absorbent body 4 may be structured so that the area corresponding to the body fluid discharge outlet (body fluid discharge outlet corresponding area) and the area behind the body fluid discharge outlet corresponding area facing the groove of the buttocks are bulged. The absorbent body 4 has a size and shape that does not exceed the top sheet 3 and the back sheet, and the outer edges of the back sheet and the top sheet 3 are bonded by adhesives such as hot melt adhesives, heat sealing, ultrasonic sealing, etc. at the front and rear edge portions of the absorbent body.

[0032] like Figure 2 As shown, side sheets 7, 7 may be provided on the outer side of the side portion of the absorbent body 4 at both ends in the short direction D2 along the long direction D1. As the side sheet 7, a water-repellent nonwoven fabric or a hydrophilic nonwoven fabric may be used.

[0033] In addition, if Figure 1 to Figure 3 In the example shown, the absorbent article 1 is a so-called wingless type without wings, but it may be configured as a winged article having wings extending from the sides. The wings can be formed by bonding the side sheets and the back sheet.

[0034] In addition, a back sheet side (non-skin side, i.e., the side facing the underwear when worn) of the absorbent article 1 may be provided with an anti-drift adhesive portion for preventing the absorbent article 1 from drifting from the underwear when the absorbent article 1 is attached to the underwear. The anti-drift adhesive portion may be formed into a plurality of strips extending in the long side direction D1 or the short side direction D2.

[0035] The total length of the absorbent article 1 may be 140 to 430 mm, and the width of the absorbent article 1 (the width of the main body excluding the wings when the wings are provided) may be 40 to 130 mm.

[0036] (Packaging Sheet)

[0037] The packaging sheet 10 in the present embodiment is paper. By using the packaging sheet 10 made of paper, it is possible to contribute to the reduction of plastics and to the achievement of sustainable development goals. In addition, paper can give a unique style, such as the appearance and feel of the soft impression of natural materials. In addition, in this specification, paper refers to plant fibers and other fibers bonded with adhesives into a thin flat plate. In particular, it can refer to plant fibers as the main raw material, for example, the plant fibers, especially cellulose fibers, in the fibers contained are more than 50%, preferably more than 80%. The plant fiber (pulp) as the raw material of paper may contain wood pulp, non-wood pulp, and old paper pulp, which may be any one of mechanical pulp and chemical pulp. The pulp may be pulp recycled from the structural components of absorbent articles and / or the packaging sheets for absorbent articles. In addition, additives may be added to the paper. As specific examples of paper, various types of paper such as Western paper, Japanese paper, processed paper, and synthetic paper can be cited. Furthermore, the paper used in other applications in the past may be, for example, paper called newspaper, printing paper (including high-quality paper), note paper, drawing paper, packaging paper, thin paper, mixed paper, etc. In the case of thin paper, it may be thin imitation paper, Indian paper, rice paper, glassine paper, facial tissue, toilet paper, filter paper, etc.

[0038] In addition, in this specification, the paper packaging sheet refers to a sheet mainly composed of the above-mentioned paper. Among the paper packaging sheets, there are obviously packaging sheets composed only of paper, and laminated sheets composed of sheets composed of paper and materials other than paper may also be included. When the packaging sheet 10 contains a sheet composed of a material other than paper, the material other than paper may be a resin film, a non-woven fabric, etc. However, the case where the packaging sheet 10 is composed only of paper is particularly preferred from the perspective of reducing plastics and / or based on the perspective of giving the product a unique natural style of paper.

[0039] The paper packaging sheet 10 may be subjected to certain processing. The processing may include, for example, pleating, embossing, calendering, waterproofing, slitting, laminating, printing, etc. By performing pleating, embossing, etc., the strength and / or softness of the paper can be improved. The packaging sheet 10 used in the present embodiment may be crepe paper after pleating. Thus, the thickness of the material becomes thin, the packaging sheet 10 is strong and soft, and the surface may have appropriate fine concave-convex, thereby improving the hand feel and grip. In addition, when the packaging sheet 10 is waterproofed, for example, a waterproofing agent containing silicone resin, paraffin resin, fluororesin, etc. can be applied to at least one of the outer surface of the packaging sheet 10 (the side exposed to the outside when the absorbent article 1 is packaged) and the inner surface on the opposite side of the outer surface. When waterproofing is performed on the inner surface of the packaging sheet 10, the anti-deviation adhesive portion provided on the back of the absorbent article 1 can be easily disassembled relative to the packaging sheet 10, so that the peeling sheet can be omitted. Here, in the manufacturing method based on the present embodiment, in which a seal is formed by pressing using a heated roller, even if waterproofing is performed on the packaging sheet 10, there is a possibility that the waterproofing agent hinders the formation of a detachable seal, and therefore it is preferably not formed on the seals 15 (described in detail later) on the two edge portions of the individually packaged absorbent article 100.

[0040] The size of the packaging sheet 10 corresponds to the size and shape of the packaged absorbent article 1. For example, when the packaging sheet 10 is fully unfolded (unfolded), the length of the long side D1 (sometimes simply referred to as the length) can be 100 to 450 mm, and the length of the short side D2 (sometimes simply referred to as the width) can be 70 to 250 mm. In the example shown in the figure, the packaging sheet 10 has a rectangular shape in the unfolded state, but it can also have a shape such as an oblong oval.

[0041] (Packaging structure for individually packaged absorbent articles)

[0042] like Figure 1 and Figure 3 As shown in FIG. 1 , the absorbent article 1 is packaged by folding it together with the packaging sheet 10 to form a separately packaged absorbent article 100. When folded, as shown in FIG. Figure 2As shown, in the following state, the absorbent article 1 is placed on the inner surface of the packaging sheet 10 so that the back sheet side of the absorbent article 1 faces it. Then, the packaging sheet 10 and the absorbent article 1 are folded together in the long side direction D1 based on the first fold line F1 and the second fold line F2 along the width direction D2. More specifically, based on the first fold line F1, the first region R1 including one end 11 of the long side direction D1 of the packaging sheet 10 is folded in the long side direction D1, and based on the second fold line F2, the second region R2 including the other end 12 of the long side direction D1 of the packaging sheet 10 is folded. The area between the first region R1 and the second region R2 of the packaging sheet 10 is the third region R3. In the example shown in the figure, the packaging sheet 10 is folded in such a manner that the second region R2 is folded first, and the first region R1 is overlapped on the outer surface of the second region R2 ( Figure 1 and Figure 2 ), or the folding order of the first region R1 and the second region R2 may be reversed. In this way, the packaging sheet 10 is folded into three parts together with the absorbent article 1 (inner three-fold), and after wrapping the absorbent article 1, the two edge parts in the short side direction D2 are sealed along the long side direction D1 to form the sealed parts 15,15.

[0043] Such a packaging form of three or more folds can be formed relatively simply, and the absorbent article 1 can be hygienically wrapped, and it is also easy to take out the absorbent article 1. In addition, the folding form is not limited to three folds, and can be four or more folds, or two folds.

[0044] Furthermore, in the individually wrapped absorbent article 100, a fixing belt 30 may be provided at the center of the short side direction D2 near the edge of the first region R1 (one end 11 of the packaging sheet 10). The fixing belt 30 may be as follows: Figure 1 As shown, the fixing tape 30 is provided along the first region R1 and the second region R2 in a manner straddling one end 11 of the packaging sheet 10. By providing the fixing tape 30, when the individually packaged absorbent article 100 is opened, the user can hold the fixing tape 30 and pull up the first region R1, thereby making it easier to open. At this time, the first region R1 is peeled off from the second region R2 located therebelow.

[0045] (Seal part)

[0046] like Figure 1 As shown, in the individually packaged absorbent article 100, the positions of the two edges in the short side direction D2 where the absorbent article 1 does not exist are sealed to form sealed portions 15, 15. In this embodiment, the sealed portions 15, 15 are formed by inserting a pair of heated rollers to press the packaging sheets 10 together in the thickness direction (described in detail later).

[0047] like Figure 1As shown, the seals 15, 15 may be formed along the entire length of the long side direction D1 of the individually packaged absorbent article 100. This is preferable from the viewpoint of preventing dirt, dust, or fingers or small objects from accidentally entering from the short side edge (obtaining sealing).

[0048] The range of the short side direction D2 of the sealing portion 15 can be a range of 20 mm from the end edge of the short side direction D2. The sealing portion 15 can be formed as a whole within the above range, or can be formed on a part of the above range, for example, at a position away from the end edge of the short side direction D2. The length (width) of the short side direction D2 of the sealing portion 15 itself is preferably 3 to 15 mm. The inner edge of the short side direction D2 of the sealing portion 15 can extend in a straight line along the long side direction D1, or can be curved, for example, in a wavy shape.

[0049] Figure 4 An enlarged view of part II including the sealing portion 15 is given. Figure 4 As shown, the sealing portion 15 may include a plurality of pressing portions (or bonding portions) 15a, 15a... that are separated from each other when viewed from above. Each pressing and bonding portion 15a, 15a... is a portion where the packaging sheets 10 are bonded to each other in the thickness direction by pressing. In the illustrated example, the portion other than the plurality of pressing portions 15a, 15a... is a non-bonding portion where the packaging sheets 10 are not bonded to each other. In this way, the pressing portions 15a, 15a... are separated from each other and exist in a dotted form. Therefore, compared with the case where the packaging sheets 10 are continuously bonded to each other along the entire surface of the sealing portion 15, for example, it is easier to peel off the packaging sheets when opening, and the opening property can be improved. In addition, it is also possible to prevent the two edges of the individually packaged absorbent article 100 from becoming excessively hard and damaging the feel.

[0050] In addition, the pressing parts 15a, 15a ... have a top view shape such as Figure 4 The example shown is a square, 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, a parallelogram, a polygon other than a quadrilateral, a circle, an ellipse, a heart, a star, a teardrop, etc. In addition, in the sealing portion 15, the size of one pressing portion 15a may be a square with a side of 0.25 to 2.5 mm, or a size having an area equivalent thereto.

[0051] <Method for manufacturing individually packaged absorbent articles>

[0052] One embodiment of the present invention relates to a method for manufacturing the above-mentioned individually packaged absorbent article 100. Referring to a schematic diagram of a manufacturing apparatus 80 for the individually packaged absorbent article 100 according to this embodiment ( Figure 5 First, the packaging sheet 10 ( Figure 1 to Figure 3) is transported in the transport direction Dt. The packaging sheet strip 10A can be obtained in a state of being rolled into a roll, and can be drawn out from such a roll for use. The packaging sheet strip 10A is transported along its long side direction, and absorbent articles 1, 1... are arranged at intervals on the inner surface of the packaging sheet strip 10A. The absorbent article 1 is arranged so that the long side direction of the absorbent article 1 is along the vertical direction Dv that is perpendicular to the transport direction Dt. Next, in the packaging part 40 of the manufacturing device 80, the packaging sheet strip 10A is folded together with the absorbent article 1 in the vertical direction Dv (i.e., the long side direction D1 of the absorbent article 1) at a folding position along the transport direction Dt. The folding is to be three-folded inwards, and preferably the absorbent article 1 is not exposed after folding.

[0053] The absorbent articles 1, 1, ... arranged at intervals in the conveying direction Dt are further conveyed to the seal forming portion 50 of the device 80 while being wrapped by the long packaging sheet 10A. Figure 5 As shown, the seal forming part 50 includes a pair of rollers 51, 52. In the seal forming part 50, at a position between the absorbent articles 1, 1... (a position where the absorbent article 1 is not provided), the packaging sheet strip 10A overlapping in the thickness direction is pressurized in the thickness direction by a pair of rollers 51, 52 to form a seal 15. In the pair of rollers, the first roller 51 is provided with pressurizing parts 53, 53... in the circumferential direction, and similarly, the second roller 52 is also provided with pressurizing parts 54, 54... in the circumferential direction. Then, when the rollers rotate, the pressurizing part 53 of the first roller 51 and the pressurizing part 54 of the second roller 52 face each other, and the packaging sheet strip 10A sandwiched therebetween is pressurized in the thickness direction.

[0054] here, Figure 6 (a) is an enlarged view of the pressing portion 53 of the first roller 51 and the pressing portion 54 of the second roller 52. Figure 6 In (a), the illustration of the sandwiched packaging sheet strip 10A is omitted. Figure 6 As shown, the surface of the pressurizing portion 53 of the first roller 51 is formed with convex portions 53a, 53a... for forming a pressurized portion. On the other hand, the second roller 52 is a roller (support roller) having a flat surface. Therefore, the size, shape, and arrangement of the convex portions 53a, 53a... for forming a pressurized portion of the first roller 51 are similar to the pressurized portions 15a, 15a... of the sealing portion 15 of the individually packaged absorbent article 100 to be obtained. Figure 4 ) correspondingly, it can be designed according to the desired size, shape and arrangement of the pressing parts 15a, 15a ... Here, the first roller 51 and the second roller 52 can be constructed so that concave and convex are formed on the surfaces of the two rollers and mesh with each other.

[0055] In this embodiment, at least one of the first rollers 51 and 52 is heated. Therefore, it can be configured so that at least the surface of at least one of the first rollers 51 and 52 is heated. As an example of a heating means, an electric heating type can be cited, for example, at the center of the rollers 51 and 52 or the pressurizing parts 53, 53 ..., 54, 54 ... ( Figure 5 and Figure 6 ) can be buried in each of the rollers, and a resistive heater (heat core) that can generate heat can be buried. In addition, means based on induction heating, heat medium circulation, steam heating, etc. can be adopted. Among them, since it is easy to process the roller surface uniformly, it is preferred to use electric heating for heating.

[0056] Thus, in order to form the sealed portion 15, the long packaging sheet 10A can be bonded in the thickness direction while being heated and pressed using a pair of heated rollers 51, 52. When the rollers are heated, they expand slightly. Figure 6 (a) and (b) are enlarged schematic diagrams of the pressurizing parts 53 and 54 of the rollers 51 and 52 before and after expansion. Figure 6 As shown in (b), the pressurizing portion 53 including the expanded convex portions 53a, 53a ... for forming the pressurizing portion expands and approaches the pressurizing portion 54, and the pressurizing portion 54 also expands and approaches the pressurizing portion 53. In addition, Figure 6 The dotted lines in (b) represent the pressurizing parts 53 and 54 before heating. In this way, due to expansion, the interval c2 between the pressurizing parts 53 of the first roller 51 and the pressurizing parts 54 of the second roller 52 in the heated state is narrower than the interval c1 between the pressurizing parts 53 of the first roller 51 and the pressurizing parts 54 of the second roller 52 before heating. In other words, the interval between the first roller 51 and the second roller 52 is smaller after heating than before heating. Therefore, by using heated rollers, the packaging sheet can be pressurized with a greater pressure than when using unheated rollers. The degree of expansion caused by the heating is fine, so this embodiment is suitable for situations where fine pressure adjustment is required.

[0057] The nip pressure of the pair of rollers is preferably 0.1 to 10 MPa, more preferably 0.3 to 5 MPa. The nip pressure may be increased by 1 to 100 kPa by heating.

[0058] Furthermore, by heating, the fibers of the paper material contained in the packaging sheet strip 10A (or packaging sheet 10) are easily entangled with each other. More specifically, the functional groups (hydroxyl groups, etc.) exposed on the surface of the cellulose fibers contained in the paper material are activated and overlapped, and chemical bonds, such as hydrogen bonds, are easily formed between the cellulose fibers contained in each of the facing packaging sheet strips 10A (or packaging sheet 10). Therefore, the packaging sheet strips 10A can be firmly combined with each other at the molecular level (microscopic). Therefore, there is no need to form a mandatory sealing portion that causes the packaging sheet strips 10A to mesh with each other.

[0059] Since paper materials do not contain fusible components, in the manufacture of individually packaged absorbent articles using paper packaging sheets, the formation of the sealing portion was attempted by physically meshing the packaging sheets with each other or using an adhesive. In this embodiment, by using a heated roller, a sealing portion with a suitable sealing strength can be formed, so there is no need to form a new surface pattern on the roller or set up an adhesive coating device, thereby saving costs and efforts. In addition, when forming a sealing portion by physically meshing the packaging sheets with each other, it is necessary to put a burden on the material of the packaging sheet, damage the packaging sheet, and use a thicker material to prevent damage. According to this embodiment, such concerns are suppressed.

[0060] The thickness of the paper packaging sheet strip 10A or the packaging sheet 10 is preferably 40 to 200 μm, more preferably 70 to 150 μm, and further preferably 90 to 150 μm. In addition, the grammage of the packaging sheet strip 10A or the packaging sheet 10 is preferably 12 to 50 g / m 2 , more preferably 15 to 40 g / m 2 , more preferably 15 to 35 g / m 2 According to the present embodiment, even when such a thin and / or light-weight paper packaging sheet is used, the seal portion 15 for individually packaging an absorbent article can be formed with an appropriate strength.

[0061] Preferably, at least one roller, preferably two rollers, are heated when the seal is formed. The temperature of the roller is above 110°C, preferably above 120°C, more preferably above 130°C, further preferably above 135°C, further preferably above 140°C. By keeping the temperature above 90°C, a seal of suitable strength can be formed. In addition, the upper limit of the temperature is a temperature to the extent that the paper material is not modified or damaged, for example, below 180°C, preferably below 170°C. In addition, heating is preferably performed in a manner that the temperature of the surface of at least the pressurizing portions 53, 54 in the roller (in the case of the pressurizing portion 53, the temperature of the surface of the convex portion 53a for forming the lamination portion) is the above-mentioned temperature. The above-mentioned temperature may be the set temperature of the device.

[0062] Furthermore, it is preferred that at least one of the rollers 51, 52, preferably both, is formed of a material having a linear thermal expansion coefficient of 5 to 50 μm / K. In addition, it is preferred that at least the pressurizing portion 53 of the first roller 51 and / or the pressurizing portion 54 of the second roller 52 is formed of a material having a linear thermal expansion coefficient of 5 to 50 μm / K. The above-mentioned thermal linear expansion coefficient is preferably 5 to 25 μm / K. By forming the rollers 51, 52 with a material having such a thermal linear expansion coefficient, appropriate expansion of the rollers 51, 52 can be obtained when heated. That is, the above-mentioned effect of being able to reduce the interval between the rollers 51, 52 can be further improved, and at the same time, excessive expansion can be prevented, making it easy to adjust the pressing pressure when the seal is formed during operation.

[0063] The material constituting the roller is preferably an inorganic material including metal and ceramic, and more preferably a metal. The metal constituting the roller may be a single metal or an alloy, and specific examples thereof include superhard alloy, stainless steel (SUS430, SUS304, etc.), carbon steel, high-speed steel, die steel, iron, gold, copper, brass, aluminum, etc. Among them, high-speed steel and die steel are preferred because they have a suitable linear thermal expansion coefficient and can cause the roller to expand appropriately when heated.

[0064] [Example]

[0065] A paper packaging sheet (thickness 90 μm, basis weight 18 g / m2) with a length of 240 mm in the long side direction was prepared. 2 ), and Figure 1 and Figure 2 The packaging sheet 10 shown is similarly folded inwardly three times to obtain a folded body, which is inserted between a pair of rollers made of high-speed steel (linear thermal expansion coefficient 11.2 μm / K) in a direction perpendicular to the folding direction, and a seal portion with a width of 6 mm is formed by applying pressure in the thickness direction. As a pair of rollers, a folded body is obtained as shown in FIG. Figure 6 As explained above, one is a roller having a convex portion for forming a nip portion on the surface, and the other is a flat roller without concave and convex portions on the surface. In addition, the roller pressure without heating was set to 3.3 MPa, and the rotation speed of the roller was 350 rpm.

[0066] Then, the temperature of the surface of the roller (temperature of the pressurizing portion) was changed to form the sealed portion, and the sealing properties of the sealed portion at each temperature were visually evaluated. The evaluation was performed based on the following criteria.

[0067] ○: No opening.

[0068] Δ: An opening of less than 5 mm was observed.

[0069] ×: There is an opening larger than 5 mm

[0070] The opening refers to a state in which the edge of the packaging sheet exposed outside when the inner three-fold is not bonded to the packaging sheet overlapped below. The above "○" and "Δ" are the ranges allowed as the sealed portion.

[0071]

Table 1

[0072] Roller temperature 100℃ 120℃ 130℃ 140℃ 150℃ Encapsulation × Δ Δ ○ ○

[0073] As shown in Table 1, in the case of the metal roll (high-speed steel roll) in this example, it is found that the sealing property of the seal portion can be improved by setting the surface temperature of the roll to 130° C. or higher, more preferably 140° C. or higher.

[0074] The present invention is described above based on the embodiments, but the present invention is not limited to these embodiments. The above embodiments can be variously changed, modified, replaced, added, deleted and combined within the scope of the patent claims, which also belong to the technical scope of the present invention. In addition, the above structural elements can be combined arbitrarily.

[0075] Furthermore, preferred embodiments of the present invention are described below.

[0076] (Note 1)

[0077] Note 1 relates to a method for manufacturing individually packaged absorbent articles comprising a paper packaging sheet and absorbent articles individually packaged by the packaging sheet, comprising: placing the absorbent articles on the inner surface of a long packaging sheet body serving as the paper packaging sheet with intervals in a conveying direction, folding the long packaging sheet body together with the absorbent articles in a direction perpendicular to the conveying direction, and pressing the long packaging sheet bodies together in a thickness direction at a position between the absorbent articles by a pair of heated rollers, wherein the temperature of at least one of the rollers is 110 to 180°C.

[0078] In the manufacture of individually packaged absorbent articles, when using paper packaging sheets, it is impossible to form a seal based on melting as with packaging sheets made of plastic materials. Therefore, the sealing techniques used in the past have remained at the physical meshing of packaging sheets with each other, the use of adhesives, etc. In response to this, the inventors of the present invention have conducted careful research and found that the method described in the above-mentioned Note 1 uses a pair of rollers heated at a specified temperature to press the long strips of packaging sheets (or packaging sheets) against each other, thereby forming a seal of appropriate strength even if the packaging sheets are made of paper. In other words, it was found that a seal with appropriate sealing strength can be formed that has both the following two features: it can prevent accidental opening before use (packaging), and when opening, the packaging sheets can be peeled off from each other without difficulty and can be easily unfolded (opening).

[0079] By heating the rollers, the rollers expand slightly, thereby reducing the gap between the pair of rollers, thereby increasing the pressure during lamination. By increasing the pressure, the cellulose fibers contained in the facing paper packaging sheets are easily entangled with each other, which can improve the sealing strength between the packaging sheets. In addition, by heating the rollers, the packaging sheets are also heated, thereby increasing the activity of the functional groups on the surface of the cellulose fibers, and chemical bonds (hydrogen bonds, etc.) are easily formed between the cellulose fibers contained in the facing packaging sheets. As a result, the packaging sheets can be more firmly bonded to each other at the molecular level, which can improve the sealing strength of the two edge portions.

[0080] (Note 2)

[0081] In the aspect according to Supplementary Note 2, at least one of the rollers has a linear thermal expansion coefficient of 5 to 50 μm / K.

[0082] According to the embodiment of Supplementary Note 2, the roller expands, and the above-mentioned effect of being able to reduce the interval between the pair of rollers can be further enhanced.

[0083] (Note 3)

[0084] In the embodiment according to Supplementary Note 3, the pressure-bonding is performed without using an adhesive.

[0085] As described above, even a paper packaging sheet can form a seal with sufficient strength, so in the method involved in the above-mentioned Note 3, in the case of a paper packaging sheet, the cost and effort required for applying the adhesive commonly used in the past can be saved.

[0086] (Note 4)

[0087] In the embodiment according to Supplementary Note 4, a plurality of nip-forming portion forming projections are formed on a surface of one of the pair of rollers, and the other surface is flat.

[0088] In the method described in Supplement 4, the sealing means in which only one roller is provided with a convex portion for forming a nipple is difficult to form mechanical engagement between packaging sheets compared to the sealing means in which concavities and convexities are formed on the surfaces of both rollers of a pair of rollers and the concavities and convexities are engaged with each other. However, in the present method, a seal with sufficient strength can be formed even if the roller is not an engaging type by heating the roller.

[0089] (Note 5)

[0090] In the embodiment according to Supplementary Note 5, the thickness of the paper packaging sheet is 40 to 200 μm.

[0091] By adopting the method described in Supplementary Note 5, even a thinner packaging sheet can be more firmly sealed.

[0092] (Note 6)

[0093] The method involved in Note 6 is a separately packaged absorbent article comprising a paper packaging sheet and an absorbent article separately packaged by the packaging sheet, wherein the packaging sheet is folded together with the absorbent article in the long side direction of the packaging sheet when the absorbent article is placed on the inner surface of the packaging sheet, and the two edge portions in the short side direction perpendicular to the long side direction are sealed, and the seal is formed by heat pressing at 110 to 180°C.

[0094] According to the embodiment of Supplementary Note 6, it is possible to provide an individually packaged absorbent article having a seal portion with an appropriate seal strength even when the paper packaging sheet is used, thereby reducing costs and labor.

[0095] This application claims priority based on Japanese Patent Application No. 2022-185096 filed on November 18, 2022, the entire contents of which are incorporated herein by reference.

[0096] [Reference Signs]

[0097] 1. Absorbent articles

[0098] 3 Top sheet

[0099] 4 Absorber

[0100] 7 Side sheets

[0101] 10 Packaging Sheet

[0102] 11 One end of the long side

[0103] 12 The other end of the long side

[0104] 15 Sealing part

[0105] 15a Pressing part

[0106] 30 Fixing strap

[0107] 40 Packaging Department

[0108] 50 seal forming portion

[0109] 60 Cutting section

[0110] 80 Individually packaged absorbent article manufacturing device

[0111] 100 Individually wrapped absorbent articles

[0112] D1 Long side direction of packaging sheet

[0113] D2 Short side direction of packaging sheet

[0114] F1 1st fold line

[0115] F2 2nd fold line

[0116] R1 Area 1

[0117] R2 Area 2

[0118] R3 Area 3

Claims

1. A method for manufacturing an individually packaged absorbent article, in, The individually packaged absorbent article comprises a paper packaging sheet and an absorbent article individually packaged by the packaging sheet, including: On the inner surface of the long paper packaging sheet body, absorbent articles are placed at intervals in the conveying direction. The long packaging sheet body and the absorbent article are folded in a direction perpendicular to the conveying direction. The long strips of packaging sheets are pressed together in the thickness direction by a pair of heated rollers at positions between the absorbent articles. The temperature of at least one of the rollers is 110 to 180°C. 2 . The method for producing an individually wrapped absorbent article according to claim 1 , wherein a linear thermal expansion coefficient of at least one of the rollers is 5 to 50 μm / K. 3 .

3. The method for producing an individually packaged absorbent article according to claim 1 or 2, wherein the pressing is performed without using an adhesive. 4 . The method for manufacturing an individually wrapped absorbent article according to claim 1 , wherein a plurality of convex portions for forming nip portions are formed on a surface of one of the pair of rollers, and a surface of the other roller is flat.

5. The method for producing an individually packaged absorbent article according to claim 1 or 2, wherein the thickness of the paper packaging sheet is 40 to 200 μm.

6. An individually packaged absorbent article, in, A paper packaging sheet and an absorbent article individually wrapped by the packaging sheet, In a state where the absorbent article is placed on the inner surface of the packaging sheet, the packaging sheet is folded together with the absorbent article in the long side direction of the packaging sheet to seal both edge portions in the short side direction perpendicular to the long side direction. The seal is formed by heat compression at 110-180°C.

Images