JP2018201672A - Absorbent article - Google Patents

Abstract

To provide an absorbent article in which printing that is excellent in decorative properties and does not hinder absorption performance is applied to unwoven fabric to be used for a top sheet or the like.SOLUTION: A top sheet 10 of an absorbent article 1 has symbols, characters and the like formed by dotted hot melt type ink being printed on a body side surface or garment side surface. An average area of each dot of the hot melt type ink printed on the top sheet 10 is between 1000 μmand 2000 μm; a dot interval between the respective dots of the hot melt type ink printed on the top sheet 10 is between 50 μm and 300 μm. An area ratio occupied by the dots of the hot melt type ink in an area where the hot melt type ink is printed on the top sheet 10 is 12% or below.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an absorbent article such as a printed incontinence pad, a pants-type paper diaper, and a tape-clamped paper diaper.

  Currently, absorbent articles such as disposable paper diapers for infants and adults are widely used. These absorbent articles are configured to include a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet. The liquid-permeable top sheet is mainly composed of a nonwoven fabric, and the liquid-impermeable back sheet is composed of a plastic film such as polyethylene.

  Moreover, a pattern, a character, etc. are printed on the absorbent article for various purposes, and a printing method such as single-color printing or multi-color printing is appropriately selected according to the printing site or purpose. For example, in an absorbent article for infants, there are cases where a design of a character such as an animal is printed in multiple colors on a backsheet. Moreover, in the absorbent article for adults, the description on specifications, such as the size, front and back, and the amount of absorption of the absorbent article, may be printed in a single color.

  The printing method is appropriately selected depending on the surface property of the member to be printed, but the printing accuracy may be limited depending on the printing method. For example, when the member to be printed is a plastic film or paper, flexographic printing or gravure printing can be used, and a certain degree of printing accuracy can be obtained. Here, flexographic printing and gravure printing are systems in which a printing plate roll and a member to be printed come into contact with each other for printing.

  In this regard, various nonwoven fabrics and the like that are generally used for top sheets, three-dimensional gather sheets, individual packaging sheets, and the like are not smooth in surface as compared with plastic films and papers. Therefore, when printing is performed by the contact printing method described above, since the surface has large and small irregularities, the printing accuracy is deteriorated, and the cosmetics and visibility such as appearance are impaired. There is a problem. On the other hand, in recent years, the demand for cosmetics of printed parts has become increasingly strong for consumers. Therefore, when printing on various non-woven fabrics, it is necessary to take measures such as limiting the printing speed or enlarging the symbols and characters.

  Patent Document 1 discloses an inkjet printer that uses oil-based ink in an absorbent article manufacturing apparatus in which a pattern visible to the outside is applied to a back sheet for the purpose of manufacturing a good-looking absorbent article with good operability. And a cooling means for injecting a spray liquid for cooling at a predetermined temperature or lower, and a pattern is formed on the back sheet by discharging ink from the outer surface side of the back sheet by an ink jet printer, and then the pattern is formed by the cooling means. An apparatus for manufacturing an absorbent article that cools the formed area is disclosed.

  Patent Document 2 discloses an aqueous composition containing an aqueous polyurethane, water and a colorant for the purpose of improving the color transfer resistance characteristics of an aqueous printing ink for a nonwoven fabric article.

JP 2011-206330 A Special table 2010-509460 gazette

  However, the absorbent article manufacturing apparatus disclosed in Patent Document 1 assumes that a pattern is formed by inkjet printing on a back sheet having a relatively smooth surface to be printed. Therefore, when a pattern or the like is applied to a non-woven fabric having an uneven surface and a hydrophilic surface, a problem arises in terms of manufacturing an absorbent article having a good appearance with good operability.

  In addition, when the aqueous composition disclosed in Patent Document 2 is printed on, for example, a top sheet by ink jet printing, since it is aqueous, the printing speed is limited by the time of the drying process, causing a problem in operability.

  Accordingly, an object of the present invention is to provide an absorbent article in which a nonwoven fabric used for a top sheet or the like is printed with excellent cosmetic properties and without impairing absorption performance.

  The inventors of the present invention have conducted intensive research in view of the above problems. As a result, the hot-melt ink dots printed on the top sheet have patterns, characters, etc. formed by printing dot-like hot-melt ink on the body-side surface or clothing-side surface of the top sheet. The inventors have found that the above problems can be solved by adopting a predetermined configuration, and have completed the present invention.

(1) A first aspect of the present invention is an absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet. The top sheet has a pattern, characters, etc. formed by printing dot-like hot melt ink on the body side surface or clothing side surface, and the hot melt system printed on the top sheet. The average area of each dot of ink is 1000 μm ² or more and 2000 μm ² or less, and the dot interval of each dot of the hot melt ink printed on the top sheet is 50 μm or more and 300 μm or less. The area ratio occupied by the dots of the hot melt ink in the region where the hot melt ink is printed is 12% or less. Is an absorbent article to be.
(2) In the absorbent article according to (1), the hot melt ink is printed by ink jet printing, a printing line speed in the ink jet printing is 100 m / min or more, and the ink jet printing is the absorption In-line printing incorporated in the production line of the functional article may be used.
(3) In the absorbent article according to (1) or (2), the hot melt ink is 0.1 Pa. At 120 ° C. It may have a melt viscosity of s or less.
(4) The absorbent article according to any one of (1) to (3) further includes a liquid diffusable sheet disposed between the top sheet and the absorber, and the liquid diffusable sheet Has a pattern, characters, etc. formed by printing dot-like hot-melt ink on the body side surface or clothing side surface, and the patterns, characters, etc. are visible through the top sheet, The average area of dots of the hot melt ink in the liquid diffusive sheet is 1000 μm ² or more and 2000 μm ² or less, and the dot interval of the hot melt ink in the liquid diffusable sheet is 50 μm or more and 300 μm or less, The area ratio occupied by the hot melt ink in the region where the hot melt ink is printed on the liquid diffusive sheet may be 12% or less. There.
(5) In the absorbent article according to any one of (1) to (4), the top sheet is a thermal bond nonwoven fabric or a spun bond nonwoven fabric, and the basis weight of the top sheet is 15 g / m ^2. It may be 50 g / m ² or more.

The absorbent article of the present invention has a pattern, characters, etc. formed by printing dot-like hot melt ink on the body side surface or clothing side surface of the top sheet, and the hot melt printed on the top sheet. The average area of each dot of the system ink is 1000 μm ² or more and 2000 μm ² or less, the dot interval of each dot of the hot melt ink printed on the top sheet is 50 μm or more and 300 μm or less, and the hot melt ink is formed on the top sheet. The area ratio occupied by the dots of hot melt ink in the printed region is 12% or less. Thereby, the absorptive article by which printing which was excellent in cosmetics and did not inhibit absorption performance to the nonwoven fabric used for a top sheet etc. can be provided.

(A) And (b) is the top view seen from the body side surface of an absorbent article about the absorbent article of this invention, (c) is a top view of the packaging sheet which packages the absorbent article of this invention. It is. (A) is the image which image | photographed the area | region shown with the dotted line of the ellipse in FIG.1 (c) with the microscope, (b) is the image image | photographed with the microscope about the area | region printed most darkly in the comparative example. 2A is an image displaying dot intervals in the feed direction in the image in FIG. 2A, and FIG. 2B is an image displaying dot intervals in the feed direction in the image in FIG. It is a figure which shows the result of having measured the absorption rate about each nonwoven fabric of an Example, a comparative example, and a reference example. It is a figure which shows the result of having measured the amount of wetbacks about each nonwoven fabric of an Example, a comparative example, and a reference example.

  Hereinafter, although the absorbent article 1 based on embodiment of this invention is demonstrated in detail, these are raise | lifted for the purpose of illustration and these do not limit this invention. Note that the same number is assigned to the same element throughout the description of the embodiment.

<Absorbent article>
The absorbent article 1 according to the embodiment of the present invention may be an absorbent article 1 such as a light incontinence pad, a light incontinence liner, a sanitary napkin, a pants-type paper diaper, and a taped paper diaper. The absorbent article 1 includes a liquid-permeable top sheet 10 disposed on the body-side surface, a liquid-impermeable or liquid-permeable back sheet disposed on the clothing-side surface facing the top sheet 10, and the top And an absorbent body 11 disposed between the sheet 10 and the back sheet, whereby the absorbent body 11 is sandwiched between the top sheet 10 and the back sheet. Note that the top sheet 10, the back sheet, and the absorber 11 may be bonded to each other by an adhesive, heat fusion, or the like.

  In the description of the present specification, the longitudinal direction is a direction extending in front of and behind the wearer when the absorbent article 1 is worn. Further, the width direction is a direction transverse or orthogonal to the longitudinal direction. Moreover, in this specification, a body side surface refers to the surface which contact | abuts a wearer's skin at the time of wear of the absorbent article 1, or the surface of the side contact | abutted to a wearer's skin when the absorbent article 1 is worn, The side surface is a surface opposite to the body side surface, and is a surface that contacts the wearer's clothing when the absorbent article 1 is worn or a side that contacts the wearer's clothing when the absorbent article 1 is worn. Refers to the surface.

[Top sheet]
The top sheet 10 used in the absorbent article 1 according to the embodiment of the present invention allows body fluid to pass quickly toward the absorbent body 11 and is disposed to face the back sheet with the absorbent body 11 interposed therebetween. The Since the top sheet 10 is a sheet that comes into contact with the skin, the top sheet 10 is preferably a hydrophilic nonwoven fabric having a soft touch and a property that does not irritate the skin. Examples of hydrophilic nonwoven fabrics include synthetic fibers such as polypropylene and polyethylene, recycled fibers such as rayon, and natural fibers such as cotton, thermal bond nonwoven fabrics such as air-through nonwoven fabrics, spunlace nonwoven fabrics, spunbond nonwoven fabrics, and open polyethylene films. An openable film, a foamed film such as urethane foam, and the like can be used. From the viewpoint of air permeability and feel when worn, it is preferable to use a thermal bond nonwoven fabric or a spunbond nonwoven fabric such as a hydrophilic air-through nonwoven fabric.

The basis weight of the top sheet 10 is preferably 15 g / m ² or more and 50 g / m ² or less in terms of workability and strength. In addition, lotion, antioxidant, anti-inflammatory component, pH adjuster, antibacterial agent, moisturizer and the like may be applied to the top sheet 10 in order to reduce irritation to the skin.

[Back sheet]
The back sheet used for the absorbent article 1 according to the embodiment of the present invention is a sheet material having liquid impermeability, and is disposed to face the top sheet 10 with the absorbent body 11 interposed therebetween. As the back sheet, a sheet material using a thin plastic sheet such as a polyethylene sheet or a polyethylene laminated nonwoven fabric can be used. In addition, you may have moisture permeability for prevention of swelling.

The basis weight of the back sheet is preferably 15 g / m ² or more and 60 g / m ² or less from the viewpoint of workability and strength.

[Absorber]
The absorbent body 11 used for the absorbent article 1 according to the embodiment of the present invention contains an absorbent fiber as a base material and a super absorbent polymer (hereinafter also referred to as SAP). The absorbent fiber is not particularly limited as long as it is generally used in the absorbent article 1 such as a sanitary napkin, a diaper, a urine absorbing pad, and examples thereof include fluff pulp, cotton, rayon, acetate, tissue, absorbent paper, A hydrophilic nonwoven fabric etc. can be mentioned. Among these, it is preferable to use fluff pulp from the viewpoint of absorbability. Examples of fluff pulp include wood pulp (for example, softwood bleached kraft pulp (N-BKP) such as Southern pine and Douglas fir), synthetic fiber, polymer fiber, non-wood pulp, etc. Can do. The absorbent fibers of the absorbent body 11 preferably have a basis weight of 400 g / m ² or more and 800 g / m ² or less so as not to impair the absorption performance and the touch.

The SAP used for the absorbent body 11 is not particularly limited as long as it absorbs body fluids and can prevent backflow. Sodium polyacrylate, polyaspartate, (starch-acrylic acid) graft copolymer Those formed from materials such as a polymer, (acrylic acid-vinyl alcohol) copolymer, (isobutylene-maleic anhydride) copolymer and saponified product thereof can be used. Among these, a sodium polyacrylate copolymer is preferable from the viewpoint of the amount of absorption per mass. The SAP amount of the absorbent body 11 is preferably set to a basis weight of 50 g / m ² or more and 700 g / m ² or less, and a content of 15% by mass or more and 60% by mass or less so as not to impair the absorption performance and the touch. Is preferred.

  In the absorbent body 11, the absorbent fibers and SAP are preferably in the form of a laminated mat formed by mixing SAP particles in the absorbent fibers. Moreover, it is preferable to wrap the absorber 11 in a carrier sheet for the purpose of preventing leakage of SAP particles and stabilizing the shape of the absorber 11. The base material of the carrier sheet is not particularly limited as long as it has hydrophilicity, and examples thereof include hydrophilic nonwoven fabrics such as tissue, absorbent paper, and airlaid nonwoven fabric. When a plurality of carrier sheets are provided, the base material of the carrier sheet may be the same or different, and the way of wrapping the absorbent body 11 with the carrier sheet is not particularly limited.

Incidentally, the basis weight of the absorbent body 11 is preferably 400 g / ^{m 2} or more 1500 g / ^{m 2} or less. By making the basic weight of the absorber 11 into such a range, it is excellent in absorptivity and can prevent the leakage of a bodily fluid effectively. Moreover, the absorber 11 may be formed by laminating an upper layer absorber and a lower layer absorber. In this case, the dimensions of the upper layer absorber and the lower layer absorber in the longitudinal direction and the width direction may be such that the size of the upper layer absorber is larger than the size of the lower layer absorber, and the size of the upper layer absorber is the same as the size of the lower layer absorber. The dimension of an upper layer absorber may be smaller than the dimension of a lower layer absorber.

  The absorbent body 11 may be a single layer or a multilayer, and may be provided with a slit portion without the absorbent fibers and the superabsorbent polymer.

[Liquid diffusion sheet]
In the absorbent article 1 according to the embodiment of the present invention, a liquid diffusive sheet may be provided between the top sheet 10 and the absorbent body 11 in order to promote diffusion of body fluid to the upper surface of the absorbent body 11. Examples of the liquid diffusive sheet include nonwoven fabrics such as air-through nonwoven fabric, point bond nonwoven fabric, spunbond nonwoven fabric, and meltblown nonwoven fabric, and composite nonwoven fabrics laminated with spunbond / meltblown and spunbond / meltblown / spunbond.

The basis weight of the liquid diffusive sheet is preferably 15 g / m ² or more. The shape of the liquid diffusive sheet is not particularly limited, but is preferably a shape that can completely cover the surface of the absorbent body 11 so that bodily fluids such as urine diffuse throughout the absorbent body 11.

[Three-dimensional gather]
The body-side surface of the absorbent article 1 according to the embodiment of the present invention has a three-dimensional elastic member and a three-dimensional body along the longitudinal direction of the absorbent article 1 in order to prevent side leakage of body fluid excreted by the user. A pair of three-dimensional gathers 12 having gather sheets may be provided. The three-dimensional gather 12 is preferably fixed to the back sheet at the width direction end (fixed end) of the absorbent article 1, and the free end side is preferably folded in half at the end. And it is preferable that the elastic member for three-dimensional gathers is clamped by the three-dimensional gather sheet of the free end side folded in half. Thereby, the three-dimensional gather 12 can have a standing property and can be deformed in accordance with the wearer's body shape.

  As the elastic member for three-dimensional gathers, for example, polyurethane yarn, belt-like polyurethane film, synthetic rubber, yarn-like or belt-like natural rubber, and the like can be used, and yarn-like, string-like, and flat-like ones can be used as appropriate. . In addition, as the three-dimensional gather sheet, a water-repellent or liquid-impervious nonwoven fabric formed of hydrophobic fibers, for example, a spunbond nonwoven fabric, a meltblown nonwoven fabric, or a composite nonwoven fabric laminated with spunbond / meltblown / spunbond is used. Is done. The thickness of the elastic member for three-dimensional gathers is preferably 1240 dtex or less.

The basis weight of the three-dimensional gather sheet is preferably 10 g / m ² or more and 40 g / m ² or less.

[Packaging sheet]
The absorbent article 1 according to the embodiment of the present invention may include a packaging sheet 13 for packaging the absorbent article 1. Examples of the packaging sheet 13 include paper, polyethylene, polypropylene, polyester, polyvinyl alcohol and other resin films, spunbond nonwoven fabrics, meltblown nonwoven fabrics, composite nonwoven fabrics of spunbond / meltblown / spunbond, and composite materials thereof. Can be used. Moreover, the peeling process by a silicon | silicone etc. can also be performed inside the packaging sheet 13 which contact | connects the absorbent article 1. FIG.

The basis weight of the packaging sheet 13 is not particularly limited, but is preferably 15 g / m ² or more and 30 g / m ² or less, and 20 g / m ² or more and 25 g / m ² or less from the viewpoint of strength and workability. It is preferable.

[Hot melt ink printing]
The top sheet 10 used for the absorbent article 1 according to the embodiment of the present invention has a pattern, characters, etc. formed by printing dot-like hot melt ink on the body side surface or clothing side surface, It is preferable that the body side surface of the top sheet 10 has a pattern, characters, and the like. The hot melt ink may be printed and formed as long as it is a pattern, character, or the like. The pattern or character that is formed in the non-printing area by printing the hot melt ink is so-called white. It may be a blank pattern, a white letter, or the like, as long as it is normally printed on the absorbent article 1 such as a number, a symbol, or a figure. Moreover, a brand, a product name, etc. may be printed, and a design and a design may be printed for the purpose of improving cosmetics. In addition, the specifications of the absorbent article 1 such as a measure of the amount of absorption can be printed for the purpose of preventing misidentification when different products are used for each user of the absorbent article 1 in nursing care / hospital facilities.

The average area of each dot of hot-melt ink printed on the topsheet 10 is 1000 .mu.m ² or more 2000 .mu.m ² or less and preferably 1100 .mu.m ² or more 1700 ² below. Moreover, the dot interval of each dot of the hot-melt ink printed on the top sheet 10 is 50 μm or more and 300 μm or less, and preferably 80 μm or more and 270 μm or less. In addition, it is preferable that the dot space | interval of each dot of the hot-melt-type ink printed on the top sheet 10 is a dot space | interval in a feed direction. Moreover, the area ratio which the dot of a hot-melt-type ink occupies in the area | region where the hot-melt-type ink is printed on the top sheet 10 is 12% or less, and it is preferable that it is 9% or less. Further, the average dot interval of each dot of the hot-melt ink printed on the top sheet 10 is preferably 90 μm or more and 280 μm or less, and more preferably 100 μm or more and 270 μm or less.

  By printing the dots of hot melt ink as described above, the absorbent article 1 having fine printing with multicolor and high variability can be obtained by fine dots on the surface of the top sheet 10, and the cosmetics can be improved. It can be set as the excellent absorbent article 1. FIG. Further, since fine dots of hot melt ink adhere along the three-dimensional structure of the top sheet 10, the hot melt ink does not block the surface of the top sheet 10, and the influence on the absorption performance of the absorbent article 1 is reduced. Therefore, the absorbent article 1 can be provided with printing that does not impair the absorbent performance of the absorbent article 1.

  The hot melt ink used in the absorbent article 1 according to the embodiment of the present invention is preferably printed by ink jet printing. Accordingly, the print design can be easily changed by changing the electronic data, so that the plate switching operation can be made unnecessary. In addition, the printed design, characters, and the like may be printed at equal intervals in the feed direction in the manufacturing process of the absorbent article 1, and electronic data such as various designs, characters, etc. may be appropriately stored depending on the purpose. You can choose. In addition, unlike a contact printing method such as flexographic printing, a non-contact printing method enables printing without being influenced by surface properties such as basis weight of a printing target.

  Moreover, the printing line speed in inkjet printing is 100 m / min or more, preferably 200 m / min or more, and may be 280 m / min or less.

  Moreover, it is preferable that inkjet printing is in-line printing integrated in the manufacturing line of the absorbent article 1. FIG. Thereby, high-speed production of the absorbent article 1 becomes possible. For example, the non-woven sheet to be the top sheet 10 is conveyed to an ink jet printing apparatus, and the non-woven sheet to be the top sheet 10 is moved in the feed direction (machine direction or direction) based on the print image data transferred from the host computer. The body that becomes the skin contact surface of the wearer among the non-woven sheets that become the top sheet 10 by serial scanning in a direction (cross-machine direction or CD direction) perpendicular to the MD direction) with hot melt ink at a predetermined temperature Designs, characters, etc. are printed on the side surface or clothing side surface with hot melt ink. The ink jet printing apparatus is provided on a line for manufacturing the absorbent article 1 having the top sheet 10, the back sheet, and the absorbent body 11 disposed between the top sheet 10 and the back sheet. Also good. Moreover, although hot-melt-type ink can be cooled at normal temperature, you may provide the cooling process which cools the absorbent article 1 after inkjet printing with a cooling roll, an air blower, etc. FIG.

  There are no particular restrictions on the hot-melt ink ejection method, and a thermal method, a piezo method, or the like can be used.

  The hot melt ink has a viscosity of 0.1 Pa. At 120 ° C. s or less, preferably 0.06 Pa.s. More preferably, it has a melt viscosity of s or less. Thereby, it can be set as the absorptive article 1 which was excellent in cosmetics and was given printing which does not inhibit absorption performance.

  The hot-melt ink is not particularly limited as long as it satisfies the above-mentioned melt viscosity. The thermoplastic resin is polyolefin such as polyethylene, a mixture thereof, polyamide, polyester, polyesteramide, polyvinyl alcohol, cellulose ester, polyvinyl Pyridine, polyether, polyethylene, ethylene-vinyl acetate copolymer, copolyester, olefin block copolymer rubber, polystyrene-acrylic copolymer, terpene resin, rosin fluid, phenol resin, coumarone-indene resin and the like can be used. Examples of these hot melt inks include trade name: MDL5800 (manufacturer: EM Corporation). The mass ratio of the binder in the hot-melt ink is preferably 20% or more and 50% or less, and more preferably 30% or more and 40% or less.

  Further, these hot melt inks may contain additives such as wax and oil in order to improve the flow characteristics and the like. For example, polyalkylene wax (polyethylene wax, polypropylene wax, etc.), Fischer-Tropsch wax, linear primary alcohol, microcrystalline wax, fatty acid, carnauba wax, candelilla wax, stearamide, paraffin wax and montan wax, ethoxylation Long chain alcohols and the like can be used. These waxes may be used alone or in combination. The mass ratio of the additive in the hot melt ink is preferably 40% or more and 70% or less, and more preferably 50% or more and 60% or less.

  These hot melt inks may contain inorganic pigments, organic pigments or dyes, and are not particularly limited as long as they are usually used for hot melt inks. For example, titanium dioxide (white), carbon black (black), iron oxide (red, yellow, brown), chromium oxide (green), ferric ferric ammonium (blue), etc. may be used as the inorganic pigment. it can. Further, for example, diarylide yellow (pigment yellow), phthalocyanine blue (pigment blue), red lake (pigment red), or the like can be used as the organic pigment. The mass ratio of the pigment or dye in the hot melt ink is preferably 0.1% or more and 20% or less, and more preferably 0.5% or more and 10% or less.

  In addition to binders, additives and pigments or dyes, these hot-melt inks contain plasticizers, extenders, thickeners, defoamers, wetting agents or surfactants, antioxidants, and the like. May be.

  When ink-jet printing these hot melt inks, it is preferable to have a step of setting the temperature of the hot melt inks to 60 ° C. or higher and 150 ° C. or lower, more preferably 70 ° C. or higher and 120 ° C. or lower. preferable.

  The liquid diffusive sheet preferably has a pattern, characters, etc. formed by printing dot-like hot-melt ink on the body side surface or clothing side surface. More preferably on the side surface. It is preferable that symbols, characters, and the like printed on the surface of the liquid diffusive sheet are visible through the top sheet 10. The dot-like hot melt ink printed on the liquid diffusive sheet is preferably the same as the dot-like hot melt ink printed on the top sheet 10 described above, and the printing method is also described above. What is used in the top sheet 10 is preferably used.

  Moreover, it is preferable that the three-dimensional gather 12 has the pattern, character, etc. which are formed by printing a dot-like hot-melt-type ink on one surface or the other surface. Further, in the case of a three-dimensional gather 12 having a free end side of the three-dimensional gather sheet folded in two at the end portion and folded back to form an inner surface and an outer surface folded back to form an outer surface, The three-dimensional gather 12 may have a pattern, a character, or the like formed by printing dot-like hot-melt ink on the inner surface or the outer surface. The dot-like hot-melt ink printed on the three-dimensional gather 12 is preferably the same as the dot-like hot-melt ink printed on the above-described top sheet 10, and the above-mentioned top is also used for the printing method and the like. What is used in the sheet 10 is preferably used.

  Moreover, it is preferable that the packaging sheet 13 has the pattern, character, etc. which are formed by printing dot-like hot-melt-type ink on one side or the other side. The dot-like hot melt ink printed on the packaging sheet 13 is preferably the same as the dot-like hot melt ink printed on the top sheet 10 described above. What is used in the sheet 10 is preferably used.

[Method of manufacturing absorbent article]
There is no restriction | limiting in particular as a manufacturing method of the absorbent article 1, A conventionally well-known method is employable. For example, the hot melt ink is printed on the body-side surface or the clothing-side surface of the top sheet 10, the liquid diffusable sheet and the three-dimensional gather 12 are arranged on the top sheet 10, and the absorber 11 is then used. The top sheet 10 and the back sheet are sandwiched between the top sheet 10 and the back sheet, and the top sheet 10 and the back sheet are partially or entirely fixed using a hot melt adhesive, heat embossing, ultrasonic embossing, high frequency embossing, or the like. Can be manufactured. Further, for example, after the liquid diffusible sheet and the three-dimensional gather 12 are arranged in advance on the top sheet 10, the absorber 11 is sandwiched between the top sheet 10 and the back sheet, and the top sheet 10 and the back sheet are partially Alternatively, it can be manufactured by fixing with a hot melt adhesive, heat embossing, ultrasonic embossing, high frequency embossing or the like over the entire circumference and applying hot melt ink to the top sheet 10.

  As mentioned above, although this invention was demonstrated using embodiment, it cannot be overemphasized that the technical scope of this invention is not limited to the range of the invention as described in said embodiment, A various change or It will be apparent to those skilled in the art that improvements can be made. Further, it is apparent from the scope of the claims that embodiments with such changes or improvements can also be included in the technical scope of the present invention.

  The following examples further illustrate the present invention. In addition, this invention is not limited to description of a following example, unless the summary is exceeded.

[Example 1]
In Example 1, hot melt ink was printed by inkjet printing on an air-through nonwoven fabric that can be used for a top sheet, a liquid diffusible sheet, a packaging sheet, and the like of an absorbent article. The basis weight of the air-through nonwoven fabric was 20 g / m ² and the fineness was 2.0 dtex. The head of the inkjet printer was a commercial product, and the printing line speed of inkjet printing was 200 m / min. The hot-melt ink used contained 40% by mass of binder, 55% by mass of wax, and 5% by mass of pigment.

  According to the nonwoven fabric of Example 1, as shown in FIGS. 1 (a) to 1 (c), it was possible to print designs, characters, etc. excellent in cosmetic properties on the nonwoven fabric using hot melt ink.

  Further, in FIG. 1C, the 3D shape measurement microscope one-shot VR-3000 (trade name, manufacturer: about the darkest printed region (the region surrounded by the dotted ellipse in FIG. 1C). (Keyence Co., Ltd.) and measured at a magnification of 120 times. The measurement areas were W: 2521.81 μm and H: 1890.74 μm. An image of the measurement area is shown in FIG. In FIG. 2, on the image, the horizontal direction is the feeding direction (machine direction or MD direction), and the vertical direction is the direction orthogonal to the feeding direction (machine crossing direction or CD direction).

2A, the average area of each dot of the hot melt ink is 1400 μm ² , and the area ratio occupied by the dots of the hot melt ink in the region where the hot melt ink is printed is 7%. there were. FIG. 3A shows the dot spacing of each dot of the hot melt ink with respect to FIG. From FIG. 3A, the dot interval of each dot in the hot melt ink feeding direction is 70 μm or more and 290 μm or less, and the average dot interval is 200 μm.

<Absorption rate>
About the nonwoven fabric of Example 1, the time which a nonwoven fabric absorbs was measured. The measurement method is as follows. The nonwoven fabric of Example 1 was used as a sample having a length of 100 mm and a width of 200 mm including the darkest printed region. 10 sheets of impregnated filter paper (trade name: Advantech # 26-WA, 200 mm × 200 mm) are put on the bat, the nonwoven fabric sample of Example 1 is placed on the filter paper, and a cylinder having a circular water injection hole with an inner diameter of 30 mm is provided. 10 mL of water was injected using a weight (load 46 g / cm ² ), and the time taken by the nonwoven fabric sample was measured (first time). 10 mL of water was injected from the first water injection to the third time at 3 minute intervals, and the time taken for the nonwoven fabric sample to absorb was measured. 4 is a measurement result of the absorption rate of the nonwoven fabric of Example 1. FIG. In addition, about the nonwoven fabric of Example 1 which does not print hot-melt-type ink, the absorption rate measurement similar to the above was performed, and it illustrated as a reference example.

<Wetback amount>
About the nonwoven fabric of Example 1, the wet back amount which is a liquid return amount was measured. The measurement method is as follows. The nonwoven fabric of Example 1 was used as a sample having a length of 100 mm and a width of 200 mm including the darkest printed region. The mass (W _A ) of 10 pieces of filter paper for measurement (trade name: Advancedtech # 2, 55φ) was measured with an electronic balance. Five sheets of impregnating filter paper (trade name: Advantech # 26-WA, 200 mm × 200 mm) were placed on the bat. 200 mL of physiological saline was weighed with a graduated cylinder, placed on a filter paper for impregnation, and allowed to stand for about 1 minute. The edge of each filter paper for impregnation was held in a vertical state and drained for 1 minute. The nonwoven fabric sample of Example 1 was placed on 5 sheets of impregnated filter paper after draining, the measurement filter paper whose mass was measured was placed on the nonwoven fabric sample, and a cylindrical weight (diameter 55 mm) was placed on the measurement filter paper. , Mass 688 g) After placing two weights on top of each other, let stand for 30 seconds, and after 30 seconds, remove the weight, the measurement filter paper, and the nonwoven fabric sample, and measure the mass (W _B ) of the measurement filter paper with an electronic balance. It was measured. The value calculated from W _B -W _A, was wet-back amount. FIG. 5 is a measurement result of the wetback amount of the nonwoven fabric of Example 1. In addition, about the nonwoven fabric of Example 1 which does not print a hot-melt-type ink, the measurement of the wet back amount similar to the above was performed, and it illustrated as a reference example.

<Running cost>
About the nonwoven fabric of Example 1, it evaluates about productivity and switchability when changing the pattern printed on a nonwoven fabric, a character, etc. several times and making it operate for one week similarly to the production line of the normal absorbent article 1. went. The evaluation results of the running cost of the nonwoven fabric of Example 1 are shown in Table 1.

<Vividness of printing>
About the nonwoven fabric of Example 1, sensory evaluation by the monitor test of 20 persons was performed about the clarity of the printed pattern, a character, etc. In addition, (double-circle) and (circle) were set as the pass. The results of the sensory evaluation of the sharpness of printing of the nonwoven fabric of Example 1 are shown in Table 1.
◎: “Visible clearly” and “Clearly visible” are 16 to 20 people 〇: “Visible clearly” and “Clearly visible” are 11 to 15 people △: “Visible clearly” “ When “clearly visible” is 6 or more and 10 or less ×: When there is no “visible” or “clearly visible” or 1 or more and 5 or less

<Texture>
About the nonwoven fabric of Example 1, the sensory evaluation by the monitor test of 20 persons was performed about softness and the touch about printed areas, such as a printed pattern and a character. In addition, (double-circle) and (circle) were set as the pass. The results of sensory evaluation of the texture of the nonwoven fabric of Example 1 are shown in Table 1.
◎: When “soft” and “feel good” are 16 or more and 20 or less ○: When “soft” and “feel good” are 11 or more and 15 or less △: “Soft” and “feel good” are 6 When the number of people is 10 or less ×: When there is no “soft” or “feel good” or 1 or more and 5 or less

[Comparative Example 1]
In Comparative Example 1, water-based ink was printed by flexographic printing on an air-through nonwoven fabric that can be used for a top sheet, a liquid diffusable sheet, a packaging sheet, or the like of an absorbent article. The basis weight of the air-through nonwoven fabric was 20 g / m ² and the fineness was 2.0 dtex. Further, the printing line speed of flexographic printing was 200 m / min. As the water-based ink, those usually used for nonwoven fabrics composed of polyurethane resin, water, colorants and the like were used.

In addition, the darkest printed region was measured at a magnification of 120 times using a 3D shape measurement microscope one-shot VR-3000 (trade name, manufactured by Keyence Corporation). The measurement areas were W: 2521.81 μm and H: 1890.74 μm. An image of the measurement region is shown in FIG. 2B, the average area of each dot of the water-based ink was 5500 μm ² , and the area ratio occupied by the dots of the water-based ink in the region where the water-based ink was printed was 20%. FIG. 3B shows the dot spacing of each dot of the water-based ink with respect to FIG. From FIG. 3B, the dot interval of each dot in the water-ink feeding direction was 100 μm or more and 250 μm or less, and the average dot interval was 190 μm.

  Moreover, also about the nonwoven fabric of the comparative example 1, similarly to Example 1, the absorption rate, the wetback amount, the running cost, the sharpness of printing, and the texture are evaluated, and the results are shown in Table 1, FIG. 4, and FIG. It was shown to.

  As described above, according to the nonwoven fabric of Example 1, printing was clear without being affected by the surface properties of the nonwoven fabric, printing was clear, there was no load on the nonwoven fabric by printing, and the texture of the nonwoven fabric was good. The sensory evaluation of the clearness and the sensory evaluation of the texture were “◯”. In addition, since a predetermined dot-shaped hot-melt ink was printed, the absorption speed and the wetback amount were good compared to the non-printed nonwoven fabric of the reference example. Therefore, according to the nonwoven fabric of Example 1, it is possible to provide an absorbent article that has excellent cosmetics and is printed without impairing the absorption performance. In terms of running cost, high-speed printing with high printing accuracy is possible, and the print image can be easily switched according to the print image data. Therefore, an absorbent article having excellent running cost can be obtained.

  Therefore, according to the ink-jet printing of the hot-melt ink according to Example 1, as shown in FIG. 1, it was possible to print a pattern, characters, etc. having excellent cosmetic properties on the nonwoven fabric.

  On the other hand, in the nonwoven fabric of Comparative Example 1, the printing line speed at the time of manufacture was the same as that in Example 1, but it was contact-type flexographic printing, not non-contact type inkjet printing. For this reason, there was a problem in the clearness of printing due to unevenness due to the basis weight of the nonwoven fabric, so the printing accuracy was low, and the sensory evaluation of the clearness of printing was “x”. And since the problem that the texture of a nonwoven fabric fell by the pressurization at the time of ink adhesion and ink application also arose, the sensory evaluation of the texture was also “x”. Further, the wetback amount was also worse than that in the non-woven fabric of the reference example that was not printed due to the influence of ink adhesion and ink pressurization. Therefore, compared with the nonwoven fabric of Example 1, it became inferior in cosmetics and became the nonwoven fabric in which absorption performance is also inhibited. In addition, since a water-based ink is used, a drying process using heat and wind is required, and since flexographic printing is performed, the operation time for switching a print image is longer than that in the first embodiment. The cost was also inferior.

1 Absorbent article 10 Top sheet 10
11 Absorber 12 Three-dimensional gather 13 Packaging sheet

Claims (5)

An absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the top sheet and the back sheet,
The top sheet has a pattern, characters, etc. formed by printing dot-like hot melt ink on the body side surface or clothing side surface,
The average area of each dot of the hot melt ink printed on the top sheet is 1000 μm ² or more and 2000 μm ² or less,
The dot interval of each dot of the hot melt ink printed on the top sheet is 50 μm or more and 300 μm or less,
The absorbent article, wherein an area ratio occupied by dots of the hot melt ink in a region where the hot melt ink is printed on the top sheet is 12% or less. The hot melt ink is printed by inkjet printing,
The printing line speed in the inkjet printing is 100 m / min or more,
The absorbent article according to claim 1, wherein the inkjet printing is inline printing incorporated in a production line of the absorbent article.   The hot melt ink is 0.1 Pa. At 120 ° C. The absorbent article according to claim 1 or 2, which has a melt viscosity of s or less. The absorbent article further includes a liquid diffusive sheet disposed between the top sheet and the absorber,
The liquid diffusive sheet has a pattern, characters, etc. formed by printing dot-like hot melt ink on the body side surface or clothing side surface,
The design, characters, etc. are visible through the top sheet,
The average area of the dots of the hot melt ink in the liquid diffusive sheet is 1000 μm ² or more and 2000 μm ² or less,
The dot interval of the hot melt ink in the liquid diffusive sheet is 50 μm or more and 300 μm or less,
4. The area ratio of the hot melt ink in a region where the hot melt ink is printed on the liquid diffusive sheet is 12% or less. 5. Absorbent article according to item. The top sheet is a thermal bond nonwoven fabric or a spun bond nonwoven fabric,
5. The absorbent article according to claim 1, wherein a basis weight of the top sheet is 15 g / m ² or more and 50 g / m ² or less.