JP5081039B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article using a hot-melt composition that functions as a wet indicator that develops color when wet and notifies the wetness.

  In recent years, a wet indicator has been used as a mechanism for notifying that it has been wet. As one of the applications, there is known a technique for notifying that an infant has urinated in combination with a disposable nonwoven absorbent product and notifying the replacement time (Patent Documents 1 and 2).

Japanese translation of PCT publication No. 2004-512425 JP 2005-261466 A

  The technique disclosed in Patent Document 1 is a mechanism in which a wet indicator that is colored from the beginning is discolored. If there is a design on the diaper surface, the design is concealed or fouled. It was.

  The technique disclosed in Patent Document 2 is a mechanism in which a colorless wet indicator develops color when it comes into contact with bodily fluids. Therefore, inconveniences such as concealment and contamination of the diaper surface are less likely to occur. There was room for improvement in terms of quick color development (responsiveness) to wetting.

  In addition, with regard to disposable non-woven fabric absorbent products in which conventional wet indicators are used, there are reports of examples in which natural coloring occurs due to humidity without being wet with urine, making it unusable. Furthermore, it has been reported that the viscosity at the time of application is very low as an application and it is difficult to apply.

  Further, in the conventional wet indicator, when the wet indicator gets wet, the coloring component contained in the wet indicator flows out, and as a result, even if the color develops, the color is lost over time (color loss), or the There were cases where the area around the wet indicator was soiled (color bleeding).

  Accordingly, the object of the present invention is to have thermoplasticity and flexibility, an initial hue is colorless, vividly develops color with good responsiveness by water wetting, and natural color development, color loss, color bleeding due to moisture absorption other than water wetting It is an object of the present invention to provide an absorbent article using a hot melt composition that hardly causes such disadvantages.

The present invention is an absorbent article comprising a top sheet, a back sheet, and an absorber interposed between both sheets, and coated with a hot melt composition that changes color when contacted with body fluid, things, without color pH 7 pH indicator which develops color in an acidic region (a) 0.1 to 5 wt%, glycerin fatty acid ester having surface activity (b). 20 to 79.8 wt%, a weight average molecular weight of 100 Polyalkylene glycol (c) in the range of ˜4000, 20 to 35% by weight, polymer having carboxyl group (d) 0 to 59.8 % by weight , solid acid at 23 ° C. other than (b) and (d) containing 0.1 to 5 wt% is an acidic substance (e), glycerin fatty acid ester having the surface activity (b) is monoglyceride self-emulsifying stearate surfactant, glyceryl Roll monostearate, glycerol monooleate, monoglyceride stearate based surfactant, provides a monoglyceride of oleic surfactant and monoglyceride stearic oleic based absorbent article from the group consisting of surfactant is at least one selected This achieves the object.

  Moreover, this invention relates to the packaging structure of the absorbent article formed by packaging the said absorbent article with the packaging material whose titanium content is less than 8 weight%.

  According to the absorbent article of the present invention, since the hot melt composition containing the components (a) to (e) is used as a wet indicator, the use of diapers for excretion of body fluids such as urine, feces and blood Person can be notified promptly. Moreover, since the selection range of the color and coating pattern at the time of discoloration of the hot melt composition is wide, an absorbent article excellent in design can be provided at a relatively low cost. The hot melt composition has thermoplasticity and flexibility, is easy to apply to an application object, and is excellent in handleability. In addition, the hot melt composition has an initial hue before water wetting, has a function of notifying water wetting when it gets wet, and has a function of notifying water wetting. Inconveniences such as color loss and color bleeding are unlikely to occur.

  In particular, the hot melt composition mainly includes a specific pH indicator and polyalkylene glycol in a specific blending ratio, so that it is excellent in thermoplasticity, flexibility and moisture resistance, and its initial hue before water wetting is colorless. When it gets wet with water, it can develop color with good responsiveness, and it is effective as a wet indicator to notify the wetness. Usually, when the blending amount of the polymer in a composition containing a hydrophilic polymer such as polyalkylene glycol is increased, the moisture resistance of the composition tends to decrease, but in the hot melt composition according to the present invention, By using an appropriate amount of polyalkylene glycol, a pH indicator and an acidic substance are taken in between the polyalkylene glycol and the glycerin fatty acid ester having a surface-active action, so that moisture resistance can be improved.

  According to the packaging structure of the absorbent article of the present invention, the absorbent article of the present invention provided with a wet indicator (the hot melt composition) having color reversibility and excellent weather resistance is accommodated. The amount of titanium contained in the packaging material can be reduced in order to reduce the amount of product waste caused by discoloration of the wet indicator due to moisture before opening, and to block the external light that causes discoloration of the wet indicator. It can be reduced as compared with conventional products, and a high-quality packaging structure can be provided at low cost.

  Hereinafter, first, the hot-melt composition used for the absorbent article of the present invention will be described. The hot-melt composition according to the present invention is a wet indicator composition that develops color when wet and notifies the wetness, and is pH-indicator (a) that is substantially colorless at pH 7 and develops color in the acidic region; It contains a glycerol fatty acid ester (b) having an action, a polyalkylene glycol (c), a polymer (d) having a carboxyl group, and an acidic substance (e) other than (b) and (d).

[PH indicator (a) which is substantially colorless at pH 7 and develops color in the acidic region]
In the hot melt composition according to the present invention, the pH indicator (a) (hereinafter also referred to as pH indicator (a)) that is substantially colorless at pH 7 and develops color in the acidic region is one that develops the hot melt composition. .

As the pH indicator (a), those having a lactone structure generally referred to as a color former are preferred from the thinness of hue before wetting and the vividness of color development after wetting. The pH indicator (a) can be appropriately selected from known pH indicators whose initial hue before water wetting is substantially colorless according to the desired color at the time of discoloration. For example, when changing to blue, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide can be used as the pH indicator (a). When the color is changed to red, 3,6-bis (diethylamino) fluorane-γ- (4′-nitro) -anilinolactam can be used as the pH indicator (a). When the color is changed to green, 2-N, N-dibenzylamino-6-diethylaminofluorane can be used as the pH indicator (a). Among them, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methyl-3-indolyl) -4-azaphthalide shows sufficient color developability even in a relatively small amount. It is preferably used as a pH indicator (a).

  The blending amount of the pH indicator (a) in the hot melt composition according to the present invention is in the range of 0.1 to 5% by weight, particularly 0.3 to 2.5% by weight, based on the weight of the hot melt composition. It is preferable. When the blending amount of the pH indicator (a) is less than 0.1% by weight, the vividness of color development after water wetting is poor. On the other hand, when it exceeds 5% by weight, the initial hue before wetting is undesirably dark.

[Glycerin fatty acid ester (b) having surface active action]
The main purpose of adding the glycerin fatty acid ester (b) having a surface-active action to the hot melt composition according to the present invention is as follows. 1) Helps to disperse each component in the hot melt composition, and the hydrophilic substance and the hydrophobic substance. Two are to make mixing uniform, and 2) to prevent inconveniences such as color loss and color blur when used as a wet indicator. That is, in the present invention, the glycerin fatty acid ester (b) having a surface active action is used not only as a surfactant but also as an inhibitor against color loss and color blur.

  The purpose of 2) will be further described. This type of wet indicator composition (hot melt composition) is usually mixed with a substance having a surfactant activity (surfactant), but depending on the type of surfactant to be blended, the wet indicator composition When the application part (indicator) gets wet with water, the surfactant contained in the application part flows out together with the coloring component, so that no color develops even when the application part gets wet with water, or Even if the coated portion develops color, the color is lost over time (color loss), or the periphery of the coated portion is stained (color bleeding). On the other hand, when a glycerin fatty acid ester having a surfactant activity is used as the surfactant, there is no risk of causing such inconvenience.

  Examples of the glycerin fatty acid ester (b) having a surface active action include monoglyceride self-emulsifying stearic surfactant, glycerol monostearate, glycerol monooleate, monoglyceride stearin surfactant, monoglyceride olein surfactant, monoglyceride Examples include stearin / olein surfactants. Particularly preferred as the glycerin fatty acid ester (b) having a surface active action is a monoglyceride self-emulsifying stearic surfactant (medium purity monoglyceride self-emulsifying stearic surfactant). By containing a monoglyceride self-emulsifying stearic surfactant in the hot melt composition, the hot melt composition can be stored over time and the color developability over time can be effectively prevented.

  The glycerin fatty acid ester (b) having a surface active action according to the present invention does not include a glycerin fatty acid ester having no surface active action, for example, a glycerin fatty acid ester such as triglyceride or a part of diglyceride.

The blending amount of the glycerin fatty acid ester (b) having a surfactant activity in the hot melt composition according to the present invention is in the range of 20 to 79.8 % by weight, particularly 25 to 65% by weight, based on the weight of the hot melt composition. It is preferable that it exists in. When the blending amount of the glycerin fatty acid ester (b) having a surface active action is less than 20% by weight, the above-described effects cannot be obtained sufficiently, whereas when the blending amount exceeds 79.8 % by weight, the viscosity is reduced. The coating processability and moisture resistance are reduced, which is not preferable.

[Polyalkylene glycol (c)]
The polyalkylene glycol (c) in the hot melt composition according to the present invention improves the moisture resistance of the hot melt composition or adjusts the color responsiveness.

  Examples of the polyalkylene glycol (c) include polyethylene glycol and polypropylene glycol.

  The polyalkylene glycol (c) preferably has a weight average molecular weight in the range of 100 to 4000, particularly 500 to 2000. By using a polyalkylene glycol (c) having a weight average molecular weight within such a range, a glycerin fatty acid ester (b) [(medium purity) monoglyceride self-emulsifying stearic interface having a surface active action as described below. It is possible to avoid adverse effects caused by using the activator]. That is, when the glycerin fatty acid ester having the above-described surfactant action is used as the surfactant in the hot melt composition, the hydrophilicity of the hot melt composition is lowered as compared with the case of using other surfactants. As a result, the time (color change time) from when the hot melt composition is wet to water until it develops color tends to be longer. On the other hand, the hot melt resulting from the glycerin fatty acid ester having the surface active action by using the polyalkylene glycol having a weight average molecular weight in the range of 100 to 4000 together with the glycerin fatty acid ester having the surface active action as described above. A decrease in hydrophilicity of the composition is effectively prevented, and it is possible to prevent the color change time from being prolonged.

  The blending amount of the polyalkylene glycol (c) in the hot melt composition according to the present invention is preferably in the range of 20 to 35% by weight, particularly 10 to 35% by weight with respect to the weight of the hot melt composition. If the blending amount of the polyalkylene glycol (c) is less than 20% by weight, the above-mentioned effects cannot be obtained sufficiently. On the other hand, if it exceeds 35% by weight, the moisture resistance is lowered, which is not preferable.

[Polymer having carboxyl group (d)]
The polymer (d) having a carboxyl group in the hot melt composition according to the present invention improves the moisture resistance of the hot melt composition and adjusts the viscosity. In particular, an alkylene acrylic acid copolymer is preferable in terms of compatibility with other raw materials.

  Examples of the polymer (d) having a carboxyl group include EAA (ethylene acrylic acid), EMAA (ethylene methyl acrylate), and EMMA (ethylene methyl methacrylate).

The blending amount of the polymer (d) having a carboxyl group in the hot melt composition according to the present invention is in the range of 0 to 59.8 % by weight, particularly 20 to 59.8 % by weight, based on the weight of the hot melt composition. Preferably there is. When the blending amount of the polymer (d) exceeds 59.8 % by weight, the initial hue before wetting of the hot melt composition becomes dark, which is not preferable.

[Acid substances (e) other than (b) and (d)]
The acidic substance (e) (hereinafter also referred to as acidic substance (e)) other than (b) and (d) in the hot melt composition according to the present invention is a pH indicator (a) compounded in the hot melt composition. Formulated as a developer for color development when wet.

  Examples of the acidic substance (e) include citric acid, succinic acid, gluconic acid, lactic acid, fumaric acid, malic acid, oxalic acid, acetic acid, formic acid, uric acid, hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid.

  The acidic substance (e) is preferably blended with an acid that is solid at 23 ° C. from the viewpoint of making the initial color of the hot melt composition before wetting wet. Further, the acidic substance (e) is preferably a solid at 23 ° C. from the viewpoint of sufficiently expressing the wet indicator function of notifying the wetness.

  The blending amount of the acidic substance (e) in the hot melt composition according to the present invention is 0.1 to 5% by weight, particularly 0.5 to 1.5% by weight, based on the weight of the hot melt composition. preferable. If the blending amount of the acidic substance (e) is less than 0.1% by weight, the color development after water wetting is thin, whereas if it exceeds 5% by weight, the initial hue before water wetting is too dark.

  The surface active glycerin fatty acid ester (b), polyalkylene glycol (c), and carboxyl group-containing polymer (d) constituting the hot melt composition according to the present invention have coating suitability at low temperatures. In view of preventing the thermal deterioration, those having a softening point (R & B type) of 130 ° C. or less are preferable.

  The measuring method of the R & B type softening point is defined by the softening point test method by the ring and ball method according to “Japanese Industrial Standard” JIS (JAPAN Industrial Standard) K 6863-1944.

  The hot melt composition according to the present invention can maintain a color changing function even when continuously heated at 130 ° C. for 24 hours, and is excellent in heat resistance. Here, “can maintain the color changing function” means that the hot melt composition heated under the above conditions can change color as before heating when it comes into contact with a body fluid such as urine.

  The hot melt composition according to the present invention can maintain a color changing function even when left in an environment of room temperature of 40 ° C. and relative humidity of 80% RH for 24 hours, and is excellent in moisture resistance. Here, “can maintain the color changing function” means that the hot melt composition left in the environment can change color in the same manner as before being left in the environment when it comes into contact with body fluid such as urine. means.

  The softening point of the hot melt composition according to the present invention is preferably 75 to 100 ° C., more preferably 75 to 90 ° C., from the viewpoint of improving applicability by low temperature application. The softening point can be adjusted, for example, by adjusting the blending ratio of the polymer (d) having a carboxyl group and other components.

  In the hot melt composition according to the present invention, the viscosity when the temperature of the hot melt composition is 80 to 130 ° C. is preferably adjusted to a range of 20 to 12000 mPa · s, more preferably 2000 to 8000 mPa · s. can do. Many of the hot melt compositions (wet indicator compositions) used in conventional diapers of this type have a viscosity range of approximately 1000 to 2000 mPa · s at a temperature of 80 to 130 ° C. Since the adjustable range is narrow, the application method is limited, only a simple application pattern such as a straight line or a simple figure can be handled, the hot melt composition is likely to scatter around and cause poor application during application, There was inconvenience such as. On the other hand, since the hot melt composition according to the present invention can be adjusted to the above-mentioned viscosity range, there is a wide range of selection of the coating method, and various methods such as an ink jet method that could not be used in the conventional hot melt composition coating. Thus, a complicated coating pattern can be formed, and the hot melt composition can be prevented from being scattered and poorly coated during coating.

  Next, the absorbent article of the present invention using the above-described hot melt composition according to the present invention will be described with reference to the drawings based on preferred embodiments thereof. FIG. 1 shows an unfolded disposable diaper as a first embodiment of the present invention. 2 is a cross-sectional view taken along line II in FIG.

  The diaper 1 of the first embodiment includes a liquid-permeable top sheet 2, a moisture-permeable and liquid-impermeable back sheet 3, and a liquid-retaining absorbent 4 interposed between both sheets 2 and 3. ing. As shown in FIG. 1, the diaper 1 is formed substantially vertically long, has a crotch portion A at the center in the longitudinal direction, and extends from the crotch portion A to the front and back in the longitudinal direction and a back side portion B and a back. It has a side C. The crotch part A is a part located on the wearer's crotch when wearing the diaper, the ventral part B is a part located on the wearer's belly side, and the back part C is a part located on the wearer's back side. The crotch part A is a central region when the diaper longitudinal direction is divided into three equal parts.

  The diaper 1 has an hourglass-like outline in which the central part in the longitudinal direction where the crotch part A is located is constricted in the unfolded state shown in FIG. The top sheet 2 and the back sheet 3 extend outward from the left and right side edges and both front and rear ends of the absorbent body 4, and are bonded to each other by a bonding means such as an adhesive at their extending portions. The back sheet 3 defines an hourglass-like contour of the diaper 1. The top sheet 2 has a width dimension that is smaller than the width dimension of the back sheet 3, and the left and right edges (both edges in the diaper width direction) of the top sheet 2 are the left and right sides of the back sheet 3. It is located inward in the diaper width direction than the edges (both edges of the diaper width direction).

  The absorbent body 4 is formed by coating a liquid-retaining absorbent core 41 with a liquid-permeable covering sheet 42. The absorbent core 41 is configured to include an absorbent material such as pulp fiber or absorbent polymer, and is substantially vertically long and has an hourglass-like outline with a central portion in the longitudinal direction constricted in a plan view. The absorbent core 41 is entirely covered with a covering sheet 42 except for both end faces in the longitudinal direction. The covering sheet 42 covers the absorbent core 41 to maintain its shape retaining property, and prevents the constituent components of the absorbent core 41 such as the absorbent polymer from falling off. The absorbent body 4 is arranged at the center of the diaper width direction between the top sheet 2 and the back sheet 3 so that the longitudinal direction thereof coincides with the diaper longitudinal direction.

  The covering sheet 42 is composed of two sheets having different dimensions. One upper cover sheet having the same dimensions as the length of the absorbent core 41 in the longitudinal direction and the width direction (the length in the width direction of the absorbent core 41 here means the maximum length in the width direction). 42a, and the other one is a lower covering sheet 42b whose longitudinal length is the same as the longitudinal length of the upper covering sheet 42a (absorbent core 41), but wider than the upper covering sheet 42a. . The upper covering sheet 42 a is disposed to face the skin facing surface of the absorbent core 41. The lower covering sheet 42 b is disposed so as to face the non-skin facing surface of the absorbent core 41, and portions extending from both side edges of the absorbent core 41 cover the skin facing surface of the absorbent core 41. It is wound up on the covering sheet 42a. The upper covering sheet 42a and the skin facing surface of the absorbent core 41 and the lower covering sheet 42b and the non-skin facing surface of the absorbent core 41 are joined by joining means such as an adhesive. .

  In addition, in this specification, a longitudinal direction is a direction parallel to the long side of an absorbent article or its structural member, and a width direction is a direction orthogonal to this longitudinal direction. Further, in the present specification, the skin facing surface is a surface of the absorbent article or its constituent member that is directed toward the wearer's skin when the absorbent article is worn, and the non-skin facing surface is the absorbent article or its configuration. It is the surface (clothing opposing surface) directed to the clothing side when the absorbent article is worn on the member.

  In the diaper 1 of the first embodiment, a hot melt composition that changes color by contact with body fluids such as urine, feces, and blood is applied between the back sheet 3 and the absorbent body 4 (lower covering sheet 42b). An indicator 5 is provided. The indicator 5 (hot melt composition) is colorless or white (substantially colorless) before use, and has a color changing function of changing to another color when in contact with a body fluid. The indicator 5 has a function as a joining means for joining the back sheet 3 and the absorbent body 4 in addition to a function as an indicator means for notifying a user (eg, a mother) of body fluid excretion of a wearer (eg, an infant). Plays. When the indicator 5 is provided, the hot melt composition may be applied on the skin facing surface of the back sheet 3, or the hot melt composition is applied on the non-skin facing surface of the absorber 4 (lower covering sheet 42b). May be.

  The indicator 5 (hot melt composition) is located at the center of the diaper width direction of the crotch part A between the back sheet 3 and the absorber 4 (lower covering sheet 42b) over the entire length of the diaper longitudinal direction of the crotch part A. It is provided continuously. When the diaper is worn, the indicator 5 provided on the back side or the abdominal side is preferably provided at a position where the wearer can be visually recognized in a prone posture or a supine posture. For example, in the case of a baby diaper, the indicator 5 has an elongated rectangular shape, and the length in the longitudinal direction is preferably 30 to 200 mm, more preferably 50 to 150 mm, and the length in the width direction. Is preferably 2 to 300 mm, more preferably 5 to 20 mm.

  The shortest distance L1 between the longitudinal end 1b near the ventral side B of the indicator 5 and the longitudinal end 1b on the ventral B side of the diaper 1 is preferably relative to the overall length of the diaper 1 in the longitudinal direction. It is in the range of 20 to 40%, more preferably 25 to 30%. Moreover, the shortest distance L2 between the longitudinal direction other end 5c near the back side part C of the indicator 5 and the longitudinal direction other end 1c on the back side part C side of the diaper 1 is relative to the overall length of the diaper 1 in the longitudinal direction. Thus, it is preferably 20 to 40%, more preferably 20 to 30%.

  The hot melt composition constituting the indicator 5 is as described above. That is, the hot-melt composition constituting the indicator 5 is pH indicator (a) 0.1 to 5% by weight which is substantially colorless at pH 7 and develops color in the acidic region, and glycerin fatty acid ester (b) 20 having a surface active action. -90 wt%, polyalkylene glycol (c) 20-35 wt%, polymer having carboxyl group (d) 0-70 wt%, acidic substance other than (b) and (d) (e) 0.1-5 Contains% by weight.

  The indicator 5 can be provided by applying the above-described hot melt composition according to the present invention to a predetermined location, and drying after application as necessary. The method for applying the hot melt composition is not particularly limited, and a contact-type application method in which the hot-melt composition is applied while being in contact with the object to be applied or a non-contact type application method in which the hot-melt composition is applied without being in contact with the object to be applied can be used. For example, various contact type coaters such as a roll coater, and non-contact type coating apparatuses such as a bead gun, a spiral gun, a summit gun, an omega gun, a spray gun, a comb gun, and an ink jet can be used.

The basis weight of the indicator 5 (coating amount of the hot melt composition), from the viewpoint of uneven coating around, preferably 10 to 50 g / m ^2, more preferably at 15-25 g / m ^2.

  Hereinafter, the diaper 1 of 1st Embodiment is further demonstrated. An outer layer sheet 6 made of a nonwoven fabric is disposed on the non-skin facing surface side of the back sheet 3. The back sheet 3 and the outer layer sheet 6 are joined by a joining means such as an adhesive. The outer layer sheet 6 has the same shape as the back sheet 3.

  The diaper 1 includes a three-dimensional gather that can rise above the widthwise side edge of the absorber 4. That is, a sheet material 70 for forming a three-dimensional gather having the elastic member 7 is disposed on each side of the diaper in the longitudinal direction to form a three-dimensional gather.

  One or more elastic members 7 (three in the first embodiment) are fixed to one side edge of the sheet material 70 for forming a three-dimensional gather in an expanded state. The sheet material 70 is joined to the surface sheet 2 along the diaper longitudinal direction at positions outside the left and right side edges of the absorbent body 4 along the diaper longitudinal direction, and the joint portion 71 is a rising base end of the three-dimensional gather. Part 71 is formed. The sheet material 70 extends outward in the diaper width direction from the rising base end portion 71, and is joined to the back sheet 3 at the extended portion. Moreover, the sheet | seat material 70 is joined to the surface sheet 2 in each front-and-back end part of a diaper longitudinal direction.

  Leg flaps 80 are formed on both sides of the crotch part A in the diaper longitudinal direction along the diaper longitudinal direction. The leg flap 80 is formed by the back sheet 4 and the outer layer sheet 6 extending outward in the diaper width direction from the rising base end portion 71 (joint portion 71) of the three-dimensional gather. The leg flap 80 includes one or a plurality of leg elastic members 8 for forming leg gathers (two in the first embodiment) fixed to the back sheet 3 in a stretched state in the vicinity of the free end in the diaper width direction. Yes. The leg elastic member 8 is disposed between the back sheet 3 and the sheet material 70 for forming a three-dimensional gather, and is not in contact with the top sheet 2. The leg elastic members 8 are arranged over the entire length of the crotch part A in the longitudinal direction.

  A pair of fastening tapes 9 and 9 are provided on the left and right edges of the back side C of the diaper 1, and the fastening tape is provided on the non-skin facing surface (surface of the outer layer sheet 6) of the ventral side B. A landing zone 10 is provided for fixing 9. The fastening tape 9 includes a tape base material and a male material of a mechanical fastener fixed to one side of the tape base material. As the male material, those known in the art can be used without particular limitation. The landing zone 10 includes a base material sheet made of a nonwoven fabric, a resin film, or the like, and a female material of a mechanical fastener bonded to the base material sheet. As the female material, a material capable of fixing the male material by pressing the male material constituting the fastening tape 9 can be used without particular limitation.

As the surface sheet 2, various types conventionally used in this type of diaper can be used, and there is no limitation as long as it can permeate liquid such as urine. For example, synthetic fiber or natural fiber And woven fabrics, nonwoven fabrics, and porous sheets. As an example of the surface sheet 2, a core-sheath structure type (including side-by-side type) composite fiber using polypropylene or polyester as a core component and polyethylene as a sheath component is formed into a web by carding and then nonwoven fabric by an air-through method (predetermined thereafter) And may be subjected to hole opening treatment). From the viewpoint of high liquid permeability (dry feeling), an apertured sheet made of polyolefin such as low density polyethylene can also be preferably used. The basis weight of the surface sheet 2 is preferably 20 to 50 g / m ² .

As the back surface sheet 3, various materials conventionally used in this type of diaper can be used, and liquid-impermeable or water-repellent and moisture-permeable materials are preferably used. Examples of the back sheet 3 include a liquid-impermeable or water-repellent porous resin film (polyethylene, polypropylene, polyethylene terephthalate, etc.), a liquid-impermeable or water-repellent nonwoven fabric, or the porous resin film and the nonwoven fabric. And the like. Examples of the liquid-impermeable or water-repellent nonwoven fabric include thermal bond nonwoven fabric, spunbond nonwoven fabric, spunbond-meltblown-spunbond (SMS) nonwoven fabric, spunbond-meltblown-meltblown-spunbond nonwoven fabric (SMMS), and the like. It is done. The basis weight of the back sheet 3 is preferably 10 to 20 g / m ² .

In addition, as the outer layer sheet 6 disposed on the non-skin facing surface side of the back sheet 3, a liquid resin-impermeable or water-repellent nonwoven fabric, a porous resin film, and the like that are also preferably used as the back sheet 3 are preferable. Used. The basis weight of the outer layer sheet 6 is preferably 15 to 35 g / m ² .

  As the absorbent core 41 constituting the absorbent body 4, various types conventionally used in this type of diaper can be used, and the type is particularly limited as long as it has liquid absorbency such as urine. Examples thereof include a material in which an absorbent material such as an absorbent polymer or pulverized pulp is sandwiched between absorbent paper and nonwoven fabric. In addition to being used in a state of being mixed in the pulp, the absorbent polymer can be dispersed on the back sheet 3 side, or can be layered and inserted in the center in the thickness direction. Or you may arrange | position partially by means, such as forming into a polymer sheet by a well-known means. Moreover, you may mix | blend the synthetic fiber, the bulky pulp fiber which performed the crosslinking process, etc. with the absorber 4, and may improve the restoring | restoration property of the compression part at the time of liquid absorption. Moreover, an absorptive polymer may not be used. As the absorbent polymer, various types conventionally used in this type of diaper can be used. For example, polyacrylic acid soda, (acrylic acid-vinyl alcohol) copolymer, polyacrylic acid soda crosslinked product , (Starch-acrylic acid) graft polymer, (isobutylene-maleic anhydride) copolymer and saponified product thereof, potassium polyacrylate, cesium polyacrylate, and the like. A mixture of seeds or more can be used.

As the covering sheets 42 (the upper covering sheet 42a and the lower covering sheet 42b) constituting the absorbent body 4, various kinds of sheets conventionally used as a mount in this type of diaper can be used. For example, a fiber material sheet or a perforated film can be used. From the viewpoint of good liquid permeation, the covering sheet 42 is preferably made of a hydrophilic fiber sheet. As the hydrophilic fiber sheet, paper such as tissue paper and various non-woven fabrics can be used. Examples of the non-woven fabric include non-woven fabrics made of hydrophilic fibers such as cotton and rayon, and non-woven fabrics made by subjecting synthetic resin fibers to a hydrophilic treatment. Specific examples include a spunbond nonwoven fabric, a spunlace nonwoven fabric, an airlaid nonwoven fabric, and an air-through nonwoven fabric treated with a surfactant. The basis weight of the covering sheet 42 is preferably 12 to 20 g / m ² .

  As the elastic members 7 and 8, various members conventionally used in this type of diaper can be used. For example, thread rubber or flat rubber made of olefin rubber, urethane rubber, styrene rubber, polyurethane or the like. Urethane foam bands and the like are used.

  The diaper 1 of 1st Embodiment can be used similarly to a normal expansion | deployment type diaper. Since this diaper 1 is equipped with the indicator 5 which consists of a hot-melt composition containing the component (a)-(e) mentioned above, the excretion of bodily fluids, such as urine, feces, blood, etc. is promptly given to the user of a diaper. I can inform you. The indicator 5 is excellent in responsiveness to body fluids, and can change color within 1 minute after contact with the body fluids.

  In addition, since the indicator 5 is substantially colorless (colorless or white) before coming into contact with the body fluid, the printing design is concealed by the indicator 5 even if the printing design is applied at a position overlapping the indicator 5, There is no risk of being soiled, and the diaper print design can be freely designed without considering the indicator. Further, since the indicator 5 is excellent in heat resistance, moisture resistance, and weather resistance (light resistance) and hardly causes inconveniences such as color loss and color bleeding, the above-described discoloration function of the indicator 5 is stably maintained for a long time. .

  Moreover, the indicator 5 returns to the color before discoloration when it is dried after it gets wet and discolors by contacting with a body fluid. Further, the indicator 5 can be changed in color again when it gets wet after drying and returning to the color before changing color, and “color change due to wetting” and “color return due to drying” can be repeated. Such color reversibility is a characteristic that this type of conventional absorbent article with an indicator function does not have, and in conventional absorbent articles with an indicator function, once the indicator is wet and discolored (colored), it is dried. Even if it does not return to the original color. For this reason, the conventional absorbent article with an indicator function, for example, before use of a diaper, if the indicator changes color due to moisture contained in the atmosphere, it must be discarded despite being unused. There was a problem. In contrast, in the diaper 1 of the present embodiment, since the indicator 5 has color reversibility, even if the indicator 5 changes color due to moisture contained in the atmosphere before use, the indicator 5 is dried to the original color. It can be returned to (substantially colorless), waste of discarding unused diapers can be prevented, and manufacturing costs can be reduced.

  Further, as described above, the hot melt composition constituting the indicator 5 has a viscosity adjustment range of 20 to 12000 mPa · s at 80 to 130 ° C. as compared with the conventional hot melt composition (wet indicator composition). Since it is wide, various coating methods can be used, and by selecting the coating method, various coating patterns such as straight lines, curves, designs, letters, etc. can be formed. Further, the hot melt composition at the time of coating can be formed. Since scattering and application failure can be suppressed, the quality of diapers can be improved (product complaints can be reduced). The wide choice of application patterns for hot melt compositions, coupled with the wide choice of colors after color development, enables the creation of diapers designed to make changing diapers fun. .

  Hereinafter, other embodiments of the absorbent article of the present invention will be described. In the following embodiment, components that are different from the diaper 1 of the first embodiment described above are mainly described, and the same components are denoted by the same reference numerals and description thereof is omitted. The description about the diaper 1 of 1st Embodiment is applied suitably to the component which is not demonstrated in particular.

  FIG. 3 is a diagram showing a second embodiment of the present invention. In the second embodiment, an intermediate sheet 9 is interposed between the back sheet 3 and the absorber 4, and the hot melt composition is applied between the back sheet 3 and the intermediate sheet 9, An indicator 5 is provided. Specifically, the indicator 5 of the second embodiment is continuously provided in the diaper width direction central portion of the crotch part A between the back sheet 3 and the intermediate sheet 9 over the entire length of the diaper longitudinal direction of the crotch part A. Is provided. When providing the indicator 5 of 2nd Embodiment, you may apply | coat a hot-melt composition on the skin opposing surface of the back surface sheet 3, and apply | coat a hot-melt composition on the non-skin opposing surface of the intermediate sheet material 9. May be.

The intermediate sheet 9 is mainly disposed for the purpose of preventing urine bleeding from the absorbent body, an absorption sub-sheet, and one-point design printing. The intermediate sheet 9 has a rectangular shape, and the length in the width direction is substantially the same as the length in the width direction of the absorbent body 4 (the length of the maximum width of the absorbent body 4). The length is substantially the same as the length of the absorbent body 4 in the longitudinal direction. The absorber 4 and the intermediate sheet 9 are joined by a joining means such as an adhesive. As the intermediate sheet 9, for example, a film, a water-repellent nonwoven fabric, a hydrophilic nonwoven fabric, a mount or the like can be used. The basis weight of the intermediate sheet 9 is preferably 10 to 50 g / m ² . According to the second embodiment having the configuration as described above, the same effects as those of the first embodiment can be obtained.

  FIG. 4 is a diagram showing a third embodiment of the present invention. In 3rd Embodiment, the said hot-melt composition is apply | coated between the surface sheet 2 and the absorber 4 (upper coating sheet 42a), and the indicator 5 is provided. Specifically, the indicator 5 of the third embodiment is continuously provided in the diaper width direction central portion of the crotch part A between the top sheet 2 and the absorbent body 4 over the entire length of the crotch part A in the diaper longitudinal direction. Is provided. When providing the indicator 5 of 3rd Embodiment, you may apply | coat a hot-melt composition on the non-skin opposing surface of the surface sheet 2, and hot-melt on the skin opposing surface of the absorber 4 (upper coating sheet 42a). A composition may be applied. According to 3rd Embodiment which has the above structures, since the effect similar to 1st Embodiment is show | played, and since the indicator 5 exists in the position nearer to a wearer's inseam rather than the absorber 4, the bodily fluid of a diaper Even if the amount of excretion is small, the indicator 5 is discolored, and it is possible to know from the outside of the diaper that there was excretion even in a small amount.

  In the present invention, the hot melt composition only needs to be applied to a location where body fluid such as urine, feces, blood and the like pass, and the application location of the hot melt composition, that is, the application location of the indicator 5 is as described above. It is not limited to the embodiment. For example, a hot melt composition can be applied between the back sheet 3 and the outer layer sheet 6 (hereinafter, this embodiment is referred to as a fourth embodiment). Specifically, for example, the hot melt composition is continuously applied over the entire length of the diaper in the crotch part A in the diaper width direction between the back sheet 3 and the outer layer sheet 6. The indicator 5 can also be provided. In the fourth embodiment, the hot melt composition may be applied on the non-skin facing surface of the back sheet 3, or the hot melt composition may be applied on the skin facing surface of the outer layer sheet 6. Compared to the first to third embodiments described above, the fourth embodiment is provided at a position closest to the outside of the diaper when worn, so the discoloration of the indicator 5 is from the outside of the diaper. There exists an effect that it is easy to be confirmed by the user.

  Moreover, when the diaper is equipped with the solid gather which can stand up above the width direction side edge part of the absorber 4 like each embodiment mentioned above, in the elastic member 7 for this solid gather formation, A hot melt composition can be applied. In this case, the elastic member 7 itself for forming a three-dimensional gather functions as an indicator for informing the excretion of body fluid.

  Moreover, the hot-melt composition may be applied to a plurality of locations in the diaper, and the application location (the location where the indicator 5 is applied) of the hot-melt composition in each embodiment described above can be combined as appropriate. For example, in the first to fourth embodiments described above, a hot melt composition can be further applied to the surface of the elastic member 7 for forming a three-dimensional gather.

  Further, the application pattern of the hot melt composition is not limited to one elongated rectangular shape as in the above-described embodiment, and can be freely designed using straight lines, curves, designs, characters, and the like. . FIG. 5 shows an example of an application pattern (coating pattern of the indicator 5) of the hot melt composition applicable to the present invention. 5 is a form in which the hot melt composition is applied on the skin contact surface of the back sheet 3, and the top sheet 2, the absorber 4 and the three-dimensional gathers are shown in FIG. 5 for ease of explanation. Is omitted. The application pattern of the hot melt composition shown in FIG. 5 can also be applied to the case where the hot melt composition is applied to other members in the diaper, for example, the top sheet 2, the absorber 4, and the outer layer sheet 6.

  The embodiment shown in FIG. 5 (a) includes a plurality (five in FIG. 5 (a)) of hot melt composition application sections (indicators) 5a to 5e that extend in the diaper longitudinal direction and are arranged in parallel in the diaper width direction. Have. The plurality of indicators include a central indicator 5a located in the center of the diaper width direction, and a plurality of indicators 5b and 5c arranged at symmetrical positions across the central indicator 5a. The central indicator 5a and the other indicators 5b and 5c other than the central indicator 5a have different colors at the time of color development, and the other indicators 5b and 5c have different colors at the time of color development according to the distance from the central indicator 5a. Is different. That is, a color is generated by the central indicator 5a, the pair of indicators 5b and 5b located at a predetermined distance from the central indicator 5a, and the pair of indicators 5c and 5c located outward in the diaper width direction from the indicator 5b. The color of the time is different. With such a configuration, it is possible to easily grasp the distribution state of the body fluid excreted in the diaper, and it is possible to detect in advance leakage from the end of the diaper.

  The embodiment shown in FIG. 5 (b) has a plurality of (5 in FIG. 5 (b)) indicators 5a to 5e extending in the diaper width direction and arranged in parallel in the diaper longitudinal direction, It is comprised similarly to embodiment shown to Fig.5 (a), and there exists an effect similar to embodiment shown to Fig.5 (a).

  The embodiment shown in FIG. 5 (c) and FIG. 5 (d) is an example in which a pattern is created with a hot melt composition (indicator 5), and the embodiment shown in FIG. The created example, the embodiment shown in FIGS. 5 (f) and 5 (g), is an example of creating a combination of symbols and characters with a hot melt composition.

  Below, the packaging structure of the absorbent article of this invention is demonstrated with reference to drawings based on the preferable embodiment. FIG. 6 shows a packaging structure (packaging package) of a disposable diaper as an embodiment of the present invention. Fig.6 (a) is a perspective view of the packaging structure of this embodiment, FIG.6 (b) is a perspective view of the content (integrated body of a diaper) of the packaging structure shown to Fig.6 (a).

  The packaging structure 20 of the present embodiment is formed by packaging the diaper 1 of the first embodiment described above with a packaging material 21, and a plurality of diapers 1 having an indicator 5 are folded inside the packaging structure 20. It is collected and stored. The packaging material 21 is formed of the same material as the packaging material in this type of packaging structure, such as polyethylene. The packaging material 21 is provided with a perforation 21 a for facilitating opening of the packaging structure 20. The above structure is the same as that of the conventional diaper packaging structure.

  The conventional diaper packaging structure with indicator function has to be discarded because the indicator will not return to its original color once the indicator has changed color due to moisture permeated from the perforation or poorly sealed part of the packaging material. There was no problem. On the other hand, since the packaging structure 20 of this embodiment can return to the color before discoloration, if the indicator 5 of the accommodated diaper 1 gets wet and discolors, if it dries, it can return to the color before discoloration. Does not cause such problems.

  In addition, the conventional diaper packaging structure with an indicator function is poor in weather resistance (light resistance) of the indicator, and the indicator discolors over time when exposed to the outside air or light. There is a problem that the material needs to contain titanium in an amount of 7 to 8% by weight or more based on the weight of the packaging material, which increases the manufacturing cost. On the other hand, since the packaging structure 20 of this embodiment is excellent in the weather resistance (light resistance) of the indicator 5 of the accommodated diaper 1 as above-mentioned, the usage-amount of titanium which becomes a cost increase factor Can be reduced as compared with conventional products, and can be manufactured at low cost. The titanium content in the packaging material 21 according to this embodiment is preferably less than 8% by weight, more preferably 3 to 5% by weight. Titanium here is titanium oxide (usually contained in the masterbatch material). Moreover, as the packaging material 21, the thing similar to what is used with this kind of packaging structure can be used.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, the absorbent article to which the present invention can be applied is not limited to unfolded diapers, so-called pants-type diapers, disposable pads, sanitary napkins, napkin-type incontinence pads, shorts covers, and brief pants having a urine absorbing function And so on.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such embodiments.

(Preparation of hot melt composition)
The surfactants (glycerin fatty acid ester having surface active action) (b) and polyalkylene glycol (c) shown in Tables 1 to 3 below are added to a heat-resistant glass beaker equipped with a stirrer, and the content is 130 ° C. or higher. Heated so as not to become. When melted, the mixture was stirred uniformly. Next, the polymer (d) having a carboxyl group was gradually added. Finally, a pH indicator (a) and an acidic substance (e) were added to prepare a hot melt composition (wet indicator composition).

  PH indicators (a), surfactants (glycerin fatty acid esters having a surfactant activity) (b), polyalkylene glycols (c), polymers having a carboxyl group (d), and acidic substances shown in Tables 1 to 3 below Details of (e) are as follows. In Tables 1 to 3 below, the numerical values described above the test item column are the blending amounts (unit: weight%) of each component.

[PH indicator (a) which is substantially colorless at pH 7 and develops color in the acidic region]
(A) -1: 3,6-bis (diethylamino) fluorane-γ- (4′-nitro) -anilinolactam (discolored red in the acidic region)
(A) -2: 2-N, N-dibenzylamino-6-diethylaminofluorane (discolored to green in the acidic region)
(A) -3: 3,3-bis (p-dimethylaminophenyl) -6-ddimethylaminophthalide (discolored to blue in the acidic region)
(A) -4: 3- (4-Diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methyl-3-indolyl) -4-azaphthalide (discolored blue in the acidic region)

[Surfactant (glycerin fatty acid ester having surface active action) (b)]
(B) -1: Medium purity monoglyceride self-emulsifying type stearic surfactant (solid at 23 ° C., a kind of glycerin fatty acid ester having a surface-active action)
(B) -2: Glycerol monostearate (solid at 23 ° C., a kind of glycerin fatty acid ester having a surfactant activity)
(B) -3: Polyoxyethylene alkylene alkyl ether (liquid at 23 ° C., a kind of nonionic polyoxyalkylene alkyl ether)
(B) -4: polyoxyethylene polyoxypropylene glycol (liquid at 23 ° C., a kind of nonionic polyoxyalkylene alkyl ether)
(B) -5: polyoxyethylene lauryl ether (softening point 70 ° C., a kind of nonionic polyoxyethylene alkyl ether)
(B) -6: alkylbenzylmethylammonium chloride (liquid at 23 ° C., a kind of cationic quaternary ammonium salt)
(B) -7: Special polycarboxylic acid type polymer surfactant (liquid at 23 ° C., a kind of anionic surfactant)
(B) -8: Ethoxylated alcohol (solid at 23 ° C., a kind of nonionic polyoxyalkylene alkyl ether)
Note that (b) -3 to 8 are not glycerin fatty acid esters having a surfactant activity.

[Polyalkylene glycol (c)]
(C) -1: Polyethylene glycol (weight average molecular weight 600) (softening point 23 ° C.)
(C) -2: Polyethylene glycol (weight average molecular weight 1000) (softening point 37 ° C.)
(C) -3: Polyethylene glycol (weight average molecular weight 3000) (softening point 53 ° C.)
(C) -4: Polyethylene glycol (weight average molecular weight 20000) (softening point 60 ° C.)
(C) -5: Polypropylene glycol (weight average molecular weight 3000) (liquid at 23 ° C.)

[Water-soluble raw material (c ′)]
(C ′)-1: polyvinyl alcohol (weight average molecular weight 3000) (liquid at 23 ° C.)

[Polymer having carboxyl group (d)]
(D) -1: EAA (MFR 1300 g / 10 min) (softening point 75 ° C.)
(D) -2: EAA (MFR 300 g / 10 min) (softening point 82 ° C.)
(D) -3: EMAA (MFR 300 g / 10 min) (softening point 80 ° C.)
(D) -4: EMMA (MFR 450 g / 10 min) (softening point 90 ° C.)

[Polymer having no carboxyl group (d ′)]
(D ′)-1: EVA (MFR 400 g / 10 min) (softening point 70 ° C.)
(D ′)-2: SIS (MFR 40 g / 10 min)

[Acid substances (e) other than (b) and (d)]
(E) -1: citric acid (e) -2: succinic acid (e) -3: acetic anhydride

(Evaluation of hot melt composition)
About the hot-melt composition produced as described above, the following test items (1) to (9) were evaluated according to the following procedures. For the following (3) to (9), a hot melt composition melted at 110 ° C. was applied onto a back sheet with a hand coater at a coating amount of 20 g / m ² to form an indicator, which was used as a test piece. . As the back sheet, a commercially available moisture permeable sheet of Kao Marys (nonwoven fabric laminated on one side) was used. These results are shown in Tables 1 to 3 below.

(1) Softening point:
The softening point of the hot melt composition was evaluated in accordance with the softening point test method by the ring and ball method according to “Japanese Industrial Standard” JIS (Japan Industrial Standard) K 6863-1944.

(2) Viscosity:
The viscosity of the hot melt composition was evaluated according to JIS K 6862 (Method A). That is, 300 g of a hot melt composition for a metal can previously melted at a temperature 10 ° C. higher than the measurement temperature is put in a test container, and when the measurement temperature is reached while sufficiently stirring with a bar thermometer in the atmosphere, the B-type viscometer (Toki Sangyo Co., Ltd. product TOKIMEC VISCOMETER MODEL: BM) was used to measure the viscosity of the hot melt composition. When stirring the hot melt composition, an appropriate rotor was used as necessary.

(3) Discoloration time:
The discoloration time is the time from when the prepared test piece is wetted under certain conditions until the color development or discoloration can be confirmed. Specifically, the time until the color development or discoloration of the indicator can be visually confirmed after dropping 32 ° C. ion-exchanged water on the indicator of the test piece is measured, and the color change time is within 10 seconds. In the case of ◎, the case of over 10 seconds and within 60 seconds is indicated as ◯, the case of over 60 seconds within 1 hour is indicated as Δ, and the case where no color is developed even after 1 hour is indicated as ×. The shorter the color change time, the better the response to water wetting and the higher the rating.

(4) Moisture resistance:
Moisture resistance is the difficulty of color development of the indicator when the prepared test piece is left in an environment of room temperature 40 ° C. and relative humidity 80% RH. ○ when the indicator does not develop color within 48 hours after standing the test piece in the environment, △ when there is no color development within 24 hours, but within 48 hours, color development within 24 hours Was marked with x. The presence or absence of color development was judged visually. The longer the color development time in the above environment, the better the moisture resistance and the higher the evaluation.

(5) Initial hue:
The initial hue is the hue of the indicator of the test piece before wetting. Specifically, after the prepared test piece was allowed to stand in an environment of room temperature 23 ° C. and relative humidity 65% RH for 24 hours, the indicator of the test piece was visually observed, and the hue of the indicator at this time was determined as the initial hue. And The case where the initial hue is colorless is indicated by ◯, the case where the initial hue is slightly colored is indicated by Δ, and the case where the initial hue is indicated by a darker color is indicated by ×. The closer the initial hue is to colorless, the higher the rating.

(6) Color development:
Color development is the hue of a test piece after wetting with water. When the indicator of the test piece is dropped with 32 ° C. ion-exchanged water after 1 hour, the indicator is visually observed, and when the indicator is sufficiently colored (highest evaluation), slightly colored. The case was Δ, and the case where it was almost indistinguishable from colorless was marked with ×.

(7) Color blur:
6 hours after dropping 32 ° C. ion-exchanged water on the indicator of the test piece, the back sheet of the test piece was visually observed, and no color bleed due to the transfer from the indicator colored on the back sheet was confirmed. The case where it was not possible was evaluated as ◯ (highest evaluation), the case where slight color development was confirmed was evaluated as Δ, and the case where strong color development was observed was rated as x.

(8) Color loss:
6 hours after dropping 32 ° C. ion-exchanged water on the indicator on the basis of the colored state of the indicator 6 hours after dropping 32 ° C. ion-exchanged water on the indicator of the test piece ○ (highest evaluation) when the color development state of the indicator is equivalent to the above standard, Δ when the color development can be confirmed when it is lower than the standard (the color is lighter), and it is difficult to confirm the color development The case was marked with x. In addition, the quality of the coloring state and the confirmation of the coloring were visually confirmed.

(9) Storage over time:
After leaving the test piece for 15 days in an environment of room temperature 23 ° C. and relative humidity 65% RH, 32 ° C. ion-exchanged water is dropped on the indicator of the test piece, and then the color or discoloration of the indicator is visually confirmed. Measure the time until completion as the color change time. If the color change time is within 10 seconds, ◎ (highest evaluation). If it exceeds 10 seconds and within 60 seconds, ○, if it exceeds 60 seconds and within 1 hour △, and x when no color was developed even after 1 hour.

  In Example 1, good results were obtained in all the evaluation items. In particular, Example 1 uses a medium-purity monoglyceride self-emulsifying stearic surfactant, which is a kind of glycerin fatty acid ester having a surfactant activity, as the surfactant (b), so color bleeding and color loss are compared. It is superior to the example. Further, in Example 1, in addition to the medium-purity monoglyceride self-emulsifying stearic surfactant, the polyalkylene glycol having a weight average molecular weight in the range of 100 to 4000 is used in combination, so that the medium-purity monoglyceride self-emulsifying stearin is used. There was almost no decrease in hydrophilicity due to the surfactant, and good results were obtained for other test items such as discoloration time. Further, from comparison between Examples 1 and 2, it can be seen that the use of a medium purity monoglyceride self-emulsifying stearic surfactant as the glycerin fatty acid ester having a surface active action is effective in improving storage stability with time.

  Since none of the comparative examples used a glycerin fatty acid ester having a surface active action, the result was inferior in color bleeding and color loss. As will be described below, the effectiveness of each component in the hot melt composition can be seen from the comparison of each comparative example.

  As shown in Comparative Examples 1 to 3, by using a pH indicator (a) that has a lactone ring and has a pH of 7 and is substantially colorless and develops an acidic region, a hot melt composition that develops colors from colorless to multiple colors is prepared. be able to.

  As shown in Comparative Examples 1 and 4 to 7, hot melt compositions can be prepared using various surfactants (b). At this time, the anionic (anionic) surfactant [(b) -7] is slightly weak in color, and the cationic (cationic) surfactant [(b) -6] has a slightly dark initial hue. However, nonionic (nonionic) surfactants [(b) -3, (b) -4, (b) -5] can be used satisfactorily without such problems. In particular, polyoxyethylene alkyl ether is excellent in color developability and good.

  As shown in Comparative Examples 1, 8 to 10, hot melts can be prepared using various polyalkylene glycols (c).

  As shown in Comparative Examples 1 and 11 to 13, hot melt compositions can be prepared using polymers (d) having various carboxyl groups. In particular, the examples using the acrylic acrylic copolymer (Comparative Examples 1 and 11) show excellent performance.

  As shown in Comparative Examples 1, 14, and 15, hot melt compositions can be prepared using various acidic substances (e). In particular, acidic substances [(e) -1, (e) -2] solid at 23 ° C. are preferable because the initial hue is also colorless.

  In Comparative Examples 16 and 17, the effect of the blending amount of the pH indicator (a) which is substantially colorless at pH 7 and develops color in the acidic region is mainly observed. When the blending amount of the pH indicator (a) is not in the range of 0.3 to 2.5% by weight, the initial hue and color developability are slightly inferior to those when it is not, but it can be used without any problem.

  In Comparative Examples 18 and 19, the influence of the blending amount of the surfactant (b) was mainly observed. When the blending amount of the surfactant (b) is not in the range of 25 to 65% by weight, the initial hue and moisture resistance are slightly inferior to those of other cases, but the surfactant (b) can be used without any problem.

  In Comparative Examples 20 and 21, the influence of the blending amount of the polyalkylene glycol (c) was mainly observed. When the blending amount of the polyalkylene glycol (c) is not in the range of 10 to 35% by weight, the moisture resistance is slightly inferior to that when it is not, but it can be used without any problem.

  In Comparative Example 22, the influence of the blending amount of the polymer (d) having a carboxyl group is mainly observed. When the blending amount of the polymer (d) is not in the range of 20 to 60% by weight, the initial hue is slightly inferior to that when it is not, but it can be used without any problem.

  In Comparative Examples 23 and 24, the influence of the blending amount of the acidic substance (e) other than (b) and (d) is mainly observed. When the blending amount of the acidic substance (e) is not in the range of 0.5 to 1.5% by weight, the initial hue and color developability are slightly inferior to those in the other cases, but it can be used without any problem.

  In Comparative Example 25, pH indicator (a) which is substantially colorless at pH 7 and develops color in the acidic region is not blended. In this case, color development does not occur at all even when ion exchange water at 32 ° C. is dropped onto the indicator (applied part of the hot melt composition). In Comparative Example 26, a pH indicator (a) that is substantially colorless at pH 7 and develops color in the acidic region is incorporated in an amount of more than 5 wt%. In this case, the initial hue of the indicator is very dark and there is little difference before and after color development, which is not suitable for use.

  In Comparative Example 27, the surfactant (b) is not blended. In this case, the hot melt composition does not disperse even when heated and melted, and it is impossible to produce a hot melt composition in which each component is uniformly dispersed, and ion-exchanged water at 32 ° C. is dropped onto the indicator. However, no color development occurs. In Comparative Example 28, the surfactant (b) is incorporated in an amount exceeding 90% by weight. In this case, the hot-melt composition is almost liquid at 23 ° C., and in the moisture-proof test, the color is completely developed without waiting for 24 hours and is not suitable for use.

  In Comparative Example 29, polyalkylene glycol (c) is not blended. In this case, the color develops completely without waiting for 24 hours in the moisture-proof test and is not suitable for use. In Comparative Example 30, polyalkylene glycol (c) is blended in a greatly exceeding 35% by weight and exceeding 55% by weight. In this case as well, as in Comparative Example 29, the color developed completely without waiting for 24 hours in the moisture-proof test, which is not suitable for use.

  In Comparative Example 31, the polymer (d) having a carboxyl group is blended in excess of 70% by weight. In this case, the initial hue is very dark and there is little difference between before and after color development, which is not suitable for use.

  In Comparative Example 32, no acidic substance (e) other than (b) and (d) is blended. In this case, color development does not occur at all even when ion exchange water of 32 ° C. is dropped on the indicator. In Comparative Example 33, an acidic substance (e) other than (b) and (d) is blended in excess of 5% by weight. In this case, the initial hue is very dark and there is little difference between before and after color development, which is not suitable for use.

  In Comparative Example 34, a water-soluble raw material (c ′) is blended in place of the polyalkylene glycol (c). In this case, the hot melt composition was not dispersed even when heated and melted, and it was impossible to produce a hot melt composition in which each component was uniformly dispersed.

  In Comparative Examples 35 and 36, a polymer (d ′) having no carboxyl group is blended in place of the polymer (d) having a carboxyl group. In this case, the hot melt was not dispersed even when heated and melted, and it was impossible to produce a hot melt composition in which each component was uniformly dispersed.

FIG. 1 is a plan view of the skin-facing surface side showing a state where the unfolded disposable diaper, which is the first embodiment of the absorbent article of the present invention, is expanded in a planar shape. FIG. 2 is a cross-sectional view schematically showing a cross section taken along line II of FIG. FIG. 3 is a view corresponding to FIG. 2 of the unfolded disposable diaper according to the second embodiment of the present invention. FIG. 4 is a view corresponding to FIG. 2 of the unfolded disposable diaper according to the third embodiment of the present invention. FIG. 5 is a plan view showing a hot melt composition application pattern (indicator formation pattern) applicable to the absorbent article of the present invention. Fig.6 (a) is a perspective view of one Embodiment of the packaging structure of the absorbent article of this invention, FIG.6 (b) is the content (integrated body of a diaper) of the packaging structure shown to Fig.6 (a). FIG.

Explanation of symbols

1 disposable diaper (absorbent article)
2 Top sheet 3 Back sheet 4 Absorbent body 41 Absorbent core 42 Cover sheet 42a Upper cover sheet 42b Lower cover sheet 5 Indicator (hot melt composition)
6 Outer layer sheet 7 Elastic member 70 for forming three-dimensional gathers Sheet material 71 for forming three-dimensional gathers Standing proximal end portion (joint portion) of three-dimensional gathers
8 Leg elastic member 80 Leg flap 9 Fastening tape 10 Landing zone 20 Packaging structure 21 of disposable diaper (absorbent article) Packaging material

Claims (4)

An absorbent article comprising a top sheet, a back sheet, and an absorbent body interposed between both sheets, and coated with a hot melt composition that changes color by contact with body fluid,
The hot melt composition, pH indicator that develops color in an acidic region with no color pH 7 (a) 0.1 to 5 wt%, glycerin fatty acid ester having surface activity (b). 20 to 79.8 wt%, by weight Polyalkylene glycol (c) having an average molecular weight in the range of 100 to 4000 (c) 20 to 35% by weight, polymer having a carboxyl group (d) 0 to 59.8 % by weight, at 23 ° C. other than (b) and (d) Containing 0.1 to 5% by weight of an acidic substance (e) which is a solid acid ,
The glycerin fatty acid ester (b) having a surface-active action includes monoglyceride self-emulsifying stearic surfactant, glycerol monostearate, glycerol monooleate, monoglyceride stearin surfactant, monoglyceride olein surfactant and monoglyceride stearin. An absorbent article that is at least one selected from the group consisting of olein surfactants . The hot melt composition was discolored wet by contact with body fluids, the absorbent article according to claim 1 Symbol placement return to dry the previous color change color. The absorptive article according to claim 1 or 2 in which said hot-melt composition changes color within 1 minute after contacting with a bodily fluid. The packaging structure of the absorbent article formed by packaging the absorbent article as described in any one of Claims 1-3 with the packaging material whose titanium content is less than 8 weight%.

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