JP4619159B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article such as a sanitary napkin, a urine pad, a cage sheet, a urine leakage sheet, or a sweat side pad, a neck pad, a breast milk pad, and more specifically, a displacement for fixing to an underwear or the like. The present invention relates to an absorbent article provided with a stop adhesive.

  Absorbent articles with anti-slip adhesive are used by fixing them to clothes such as sanitary napkins and breast milk pads, and underwear and shirts, and fixed in disposable diapers such as urine pads. What is used is known. These absorbent articles have been proposed to make the outer surface, which is a non-skin contact surface, non-woven fabric in order to improve the feeling of touch, the feeling of roughness when worn, and the appearance (see Patent Document 1).

  According to Patent Document 1, when a hot melt adhesive for preventing misalignment is applied to the outer surface, the adhesive enters between the fibers, and as a result, the portion that substantially contributes as an anti-slip adhesive is reduced and the adhesive strength is reduced. In the case where the outer surface is composed of a breathable liquid-impervious back sheet, the adhesive strength is reduced due to moisture adhering to the adhesive surface, and the absorbent article. It is said that it becomes easy to come off from underwear. According to Patent Document 1, by using a high-viscosity hot melt adhesive, a film made of an adhesive is formed without penetrating into the fibers of the nonwoven fabric, and a decrease in adhesive force can be prevented.

  Also, as an anti-slipping layer for absorbent articles, an anti-slip slip-preventing layer having a two-layer structure comprising a layer of a foam of a binder and a heat-expandable polymer bead and a polymer having a glass transition temperature of 30 ° C. or less (patented) In the case of a moisture-permeable non-skin contact layer, use of an adhesive via a thermoplastic resin barrier layer has been proposed (see Patent Document 3).

JP 2002-355266 A JP-A-1-293869 JP 2000-140016 A

However, in Patent Document 1, the hot melt adhesive does not penetrate into the fibers of the nonwoven fabric, and the adhesive strength between the adhesive and the nonwoven fabric is weak. When the article is removed from the underwear or the like, the adhesive may be peeled off from the absorbent article and may remain on the side of the underwear or the like (referred to as adhesive residue).
On the other hand, in order to reinforce the contact with the non-skin contact layer in order to prevent the above-mentioned adhesive residue, if an adhesive having a large adhesive force is used, it adheres firmly to the underwear or the like, and the absorbent article When the film is peeled off, the adhesive is broken and the adhesive remains on the underwear side, so that the adhesive residue is not solved, or the other party to be bonded such as underwear is destroyed. Furthermore, if the cohesive strength of the adhesive is strengthened so as not to cause breakage in the adhesive, the adhesive strength to underwear or the like may be reduced.

  In Patent Document 2, an anti-slip effect is exhibited against lateral misalignment, but the anti-slip layer is non-adhesive and easily peels off (floats) from the underwear against movement and deformation of the body and clothes. Therefore, since stable fixation cannot be performed, there is a problem that a twist or a shift occurs in the end, and it is necessary to add a special process for foaming the foam.

  In the method disclosed in Patent Document 3, since the thermoplastic resin serving as the barrier layer is hard and has low adhesive strength, it is difficult to bond when the non-skin contact layer is a fiber layer, and the adhesive peels off from the absorbent article. The adhesive residue that moves to the side of the underwear or the like is more likely to occur.

  Therefore, even if the non-skin contact surface is composed of a fiber assembly such as a non-woven fabric, the object of the present invention is to prevent adhesive residue of the anti-slipping adhesive, to destroy the bonded partner or to absorb the absorbent article. An object of the present invention is to provide an absorbent article provided with an anti-slip adhesive having an adhesive force that does not peel off.

The present invention is an absorbent article provided with a liquid-retaining absorbent layer and a liquid-impermeable layer, and provided with a non-skin-contacting adhesive on the non-skin contact surface,
The non-skin contact surface is composed of a fiber assembly, and the anti-slipping adhesive composed of a hot melt adhesive is laminated on the first layer on the non-skin contact surface side and the first layer. The hot melt adhesive having the laminated structure with the second layer, and the hot melt adhesive constituting the first layer has the above-mentioned purpose by the absorbent article having higher fluidity near the softening point temperature than the hot melt adhesive constituting the second layer. Achieved.

  The absorbent article of the present invention does not decrease the adhesive strength of the adhesive even when the non-skin contact surface is composed of a fiber assembly. It is possible to obtain a good misalignment preventing property that does not cause a so-called adhesive residue in which the adhesive does not migrate to another absorbent article side. In the absorbent article of the present invention, since the non-skin contact surface is composed of a fiber assembly, it is possible to obtain an absorbent article excellent in texture, feel and appearance.

The present invention will be described below based on preferred embodiments with reference to the drawings.
The sanitary napkin 1 as an embodiment of the absorbent article of the present invention is a vertically long absorbent article provided with a liquid-retaining absorbent layer 10 and a liquid-impermeable layer 20, as shown in FIGS. is there. The non-skin contact surface 3 of the sanitary napkin is provided with an anti-slip adhesive 30 used for fixing to the underwear.

  The absorbent layer 10 is composed of a liquid-permeable topsheet 11 and a liquid-retaining absorbent body 12, and the liquid-impermeable layer 20 is composed of a liquid-impermeable leak-proof sheet 21. In the present embodiment, the leak-proof sheet 21 constitutes the back layer, and the absorber 12 is disposed between the top sheet 11 and the leak-proof sheet 21. Two side cover sheets 40 are joined to both sides of the top sheet, respectively, and are arranged so as to cover the sides of the absorbent body 12 and extend beyond both side edges of the absorbent body. Is extended beyond both side edges and both side edges of the absorber. The leak-proof sheet 21 extends beyond both side edges of the absorber 12 and is joined to the top sheet 11 and the two side cover sheets 40 around the absorber 12 by heat sealing or an adhesive. Thus, in this embodiment, the surface sheet 11 and the side part cover sheet 40 comprise the skin contact surface 2 of the sanitary napkin 1, and the leak-proof sheet 21 comprises the non-skin contact surface 3. As shown in FIG. 1, a joining line is formed near the inner edge of the side cover sheet 40 by heat sealing with the top sheet 11.

  As shown in FIG. 3, the leak-proof sheet 21 of this embodiment has a laminate structure of a fiber assembly 23 composed of a resin film 22 and a nonwoven fabric, the film surface is disposed on the absorber side, and the non-skin of the sanitary napkin 1 The contact surface 3 is composed of a fiber assembly 23.

As the resin film 22, polyethylene, polypropylene, polystyrene, polyurethane having a basis weight of about 20 to 40 g / m ² and a composite thereof, a so-called moisture permeable film (an inorganic powder of about 50% by mass, for example, calcium carbonate or the like is dispersed). A film in which a polyolefin film is uniaxially or biaxially stretched to open numerous pores) can be used. The fiber assembly 23 can be composed of a nonwoven fabric, a fiber web, various woven fabrics, etc., preferably an air-through nonwoven fabric, a spunbond nonwoven fabric, a meltblown nonwoven fabric and a composite nonwoven fabric (SM SMS, SMMS, etc.) can be used.

  When the leak-proof sheet 21 is composed of a resin film and a non-woven fabric, it is possible to apply and bond an adhesive in addition to the lamination that joins the resin to the non-woven fabric in a molten state as in this embodiment.

  Further, the leak-proof sheet 21 is made of a combination of a hydrophobic spunbond nonwoven fabric-meltblown nonwoven fabric-spunbond nonwoven fabric (SMS) or a spunbond nonwoven fabric-meltblown nonwoven fabric-meltblown nonwoven fabric-spunbond nonwoven fabric (SMMS) multilayer nonwoven fabric. It can also be comprised with the sheet | seat which becomes. Moreover, what combined the hydrophobic apertured film, the three-dimensional apertured film, and the net material with the nonwoven fabric can be used instead of the resin film.

The fibers constituting the fiber assembly 23 can be selected from polyethylene, polypropylene, polyester, and composite fibers thereof from the viewpoint of the texture of the non-skin contact surface and the adhesiveness of the anti-slip adhesive, the basis weight is preferably from 10 to 100 g / m ^2, more preferably 12~50g / m ^2.

  The surface sheet 11 can be made of a material having liquid permeability, such as a nonwoven fabric, a resin film with holes, or a composite sheet in which continuous filaments are bonded to a base sheet.

  For the side cover sheet 40, a nonwoven fabric, a resin film, or the like is used. Among them, from the viewpoint of feel to the skin and prevention of liquid leakage, a sheet having a water repellent nonwoven fabric or a melt blown nonwoven fabric, and a concavo-convex process An applied resin film or the like is preferably used.

  The absorbent body 12 may be made of a material that is usually used for this type of article as long as it is liquid-retaining. In this embodiment, an absorbent sheet having a structure in which a superabsorbent polymer is sandwiched between non-woven sheets made of crosslinked pulp, which is an absorbent body for a thin sanitary napkin that is particularly preferred in terms of wearing feeling, is C-folded. The thickness and the presence / absence of a superabsorbent polymer are selected according to the mounting state and the required absorption capacity depending on the application.

  The slip prevention adhesive 30 has a laminated structure of a first layer 31 disposed on the non-skin contact surface side 3 of the sanitary napkin 1 and a second layer 32 laminated on the first layer. . As shown in FIG. 3, the first layer 31 of the anti-displacement adhesive 30 forms a layer in a shape that enters the fiber assembly 23 of the non-skin contact surface 3, and the upper surface thereof is the non-skin contact surface. 3 to the outside. The second layer 32 of the anti-displacement adhesive 30 is disposed on the first layer 31 with the same area in this embodiment. The second layer 32 adheres to the undergarment, and the sanitary napkin 1 is fixed. Before the sanitary napkin 1 is used, the second layer 32 is covered with a release sheet for protecting the anti-displacement adhesive 30 or a packaging sheet having a release process (not shown).

  The anti-slipping adhesive 30 is improved in adhesion to the non-skin contact surface 3 made of the fiber aggregate 23 by the first layer 31, and the anti-slipping adhesive 30 is less likely to fall off from the sanitary napkin 1 and remains as a residue. In addition, the second layer 32 makes it possible to obtain an appropriate adhesive force to the underwear or the like.

  The first layer 31 and the second layer 32 of the anti-displacement adhesive 30 are composed of a hot melt adhesive, and the hot melt adhesive constituting the first layer is more than the hot melt adhesive constituting the second layer. Also, the fluidity is high at least near the softening point temperature of the hot melt adhesive. The vicinity of the softening point temperature preferably refers to a temperature below the softening point temperature of −20 ° C. to a temperature higher than the softening point + 50 ° C. The softening point temperature usually indicates a temperature at which a polymer material becomes soft by heating and starts to deform. In this case, the softening point temperature is the temperature of the hot melt adhesive when heated and melted so that the hot melt adhesive can be applied. It refers to the lowest temperature that can be applied, and the vicinity of the softening point temperature is the temperature that can be applied. In normally used hot melt adhesives, the softening point temperature is 90 ° C to 110 ° C, and the vicinity of the softening point temperature is generally 70 ° C to 160 ° C. The high fluidity means that, in detail, when comparing the temperature-viscosity curves of the first layer and the second layer measured by a B-type rotational viscometer (JIS K 6862), Indicates that the rate of increase in viscosity due to temperature decrease is smaller than that in the second layer.

  Since the first layer 31 of the anti-slipping adhesive 30 has higher fluidity than the second layer 32, the first layer 31 is more impregnated into the fiber assembly 23 on the non-skin contact surface 3 than the second layer 32. growing. High impregnation means that the viscosity or hardness in the molten state or at normal temperature is smaller than that of the hot melt adhesive used for the second layer 32. Since the impregnation property is large, the first layer 31 of the anti-displacement adhesive 30 is securely fixed to the fiber assembly 23 and it is possible to prevent adhesive residue.

  A preferred hot melt adhesive will be described as the first layer 31 of the anti-displacement adhesive 30. As a hot-melt adhesive having high fluidity, the hot-melt adhesive constituting the first layer 31 of the anti-displacement pressure-sensitive adhesive 30 further reduces the temperature from the vicinity of the softening point temperature, preferably from the softening point temperature. It is preferable that the accompanying viscosity increase gradient is smaller than that of the hot melt adhesive constituting the second layer 32. The increase in viscosity accompanying a decrease in temperature refers to a change in viscosity with respect to temperature when the temperature is gradually decreased to room temperature after the hot melt adhesive is applied to the target substrate. The viscosity increase gradient of the first layer is smaller than that of the second layer. When the temperature-viscosity curve when the horizontal axis represents temperature and the vertical axis represents viscosity is compared at the same temperature, the viscosity curve of the first layer is It shows that it is located in the low viscosity side with respect to the viscosity curve of 2 layers. About this temperature-viscosity curve, it is evaluated by the viscosity in the range of approximately 100 ° C. to 200 ° C. measured by a B-type rotational viscometer (JIS K 6862).

  The first layer 31 of the anti-displacement pressure-sensitive adhesive 30 uses a hot melt adhesive having a small viscosity increase gradient accompanying a temperature decrease from the vicinity of the softening point temperature as compared with the hot melt adhesive of the second layer 32. The hot melt adhesive of the layer 31 is slowly hardened after application and can easily be impregnated (bite into) the fiber assembly 23, and the anti-displacement adhesive 30 as a whole can exhibit sufficient adhesive strength to the fiber assembly 23. It becomes possible and no adhesive residue occurs.

  As a hot-melt-adhesive used for the 1st layer 31, the change of a viscosity at the time of changing to 120 to 180 degreeC is preferable, and it is preferable that it is 8000 to 1000 cps.

  Moreover, it is preferable that the adhesive strength with the non-skin contact surface 3 of the 1st layer 31 is higher one day after application | coating compared with immediately after application | coating (measured when it cools to 20 degreeC). This is because the first layer 31 has higher impregnation and permeability to the fiber assembly 23 than a normal anti-displacement pressure-sensitive adhesive, so that an adhesive force with the fiber assembly can be obtained immediately after application. Further, the impregnation into the fiber assembly 30 proceeds, whereby a strong adhesive force is obtained. The adhesive strength between the first layer 31 and the non-skin contact surface 3 can be measured by an adhesive strength test method based on JIS Z 0237.

  The hot-melt adhesive constituting the first layer 31 of the anti-displacement adhesive 30 includes styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), and styrene-ethylene-butylene. -The adhesive containing the base polymer selected from a styrene copolymer (SEBS) etc. is preferable. From the viewpoint of increasing the cohesive force and increasing the bonding strength with the fiber assembly 23, it is preferable to include 30 to 65% by mass of a base polymer selected from a copolymer containing olefin as a main component, and 40 to 50% by mass. More preferably it contains. The base polymer is preferably a base polymer selected from amorphous ethylene-propylene copolymer, amorphous propylene-butene copolymer, amorphous polypropylene and the like.

  Next, another preferable hot melt adhesive will be described as the first layer 31 of the anti-slipping adhesive 30. As a hot melt adhesive having high fluidity in the vicinity of the softening point temperature, the first layer 31 of the anti-displacement pressure-sensitive adhesive has a larger increase rate of adhesive force under pressure than the hot melt adhesive constituting the second layer 32. It is preferably composed of a hot melt adhesive. Thus, after the first layer 31 is applied to the fiber assembly 23 of the non-skin contact surface 3 and an article such as a sanitary napkin is completed and packaged and placed in close contact with each other, the first layer 31 gradually The first layer 31 flows and deforms, impregnates the fiber assembly 23, and the adhesive force increases. As a result, the first layer 31 is securely bonded to the fiber assembly 23.

  The change in the adhesive force under pressure of the hot melt adhesive is a change in the adhesive force with time after pressurization relative to the initial adhesive force, and the rate of increase is calculated by (adhesive force with time) / (initial adhesive force) × 100. . The initial adhesive strength and the temporal adhesive strength are measured as follows.

<Measurement of initial adhesive strength>
First, a test piece is prepared by coating a hot melt adhesive having a predetermined composition, basis weight, and pattern on a sheet constituting a sanitary napkin body or a non-skin contact surface. The size, pattern, and basis weight of the hot melt adhesive are arbitrary, and the hot melt adhesive for the first layer 31 and the second layer 32 may be prepared by separately preparing test pieces. It is not necessary to prepare the size, etc., but preferably, the first layer 31 and the second layer 32 are coated in a rectangular shape having a width of 3 cm × length of 15 cm and a basis weight of 30 g / m ^2. Similarly, a separately coated test piece is prepared.
The prepared test piece is left in a measurement environment (24 to 26 ° C., 50 to 60% RH) for 30 minutes or more. Next, a test piece is affixed to a to-be-adhered body (cotton kanakin No. 1), and it pressurizes once with a 2 kg roller with a width of 6.5 cm and a diameter of about 6 cm to prepare a sample. This sample is measured for T-peel adhesion with Tensilon.

<Pressure aging adhesion measurement>
Samples are made as well as initial adhesion. On this sample, a stainless plate having a width of 3 cm and a length of 11 cm and about 150 g is placed from above, and further a 1 kg weight is placed on the sample and left to stand in an environment of 40 ° C. and 80% RH for 24 hours. A sample is taken out, and T-peel adhesion is measured with Tensilon between 3 minutes and 7 minutes after removal. In addition, about the said initial stage adhesive force and pressurization aging adhesive force, the measurement environment in Tensilon is 24-26 degreeC, 50-60% RH, and a measurement speed is 300 mm / min. To do.

Regarding the rate of increase in the adhesive strength of the hot melt adhesive under pressure, the first layer 31 of the anti-displacement pressure-sensitive adhesive 30 is preferably 300% or more, more preferably 350% or more from the viewpoint of impregnation into the fiber assembly. Preferably, the second layer 32 of the anti-slipping adhesive 30 is preferably within 300%, more preferably within 250%, from the viewpoint of peelability from underwear and the like.

  The hot melt adhesive constituting the first layer 31 is a styrene-isoprene-styrene block copolymer (SIS) or a styrene-butadiene-styrene block copolymer as a hot melt adhesive having a large increase in adhesive force under pressure. An adhesive containing a base polymer selected from (SBS), styrene-ethylene-butylene-styrene copolymer (SEBS) and the like is preferably used. In addition, the hot melt adhesive constituting the first layer 31 is easy to become familiar with the fiber assembly 23 of the non-skin contact surface 3, and from the viewpoint of increasing the adhesive force by biting into the fiber assembly 23 under pressure, The base polymer is preferably contained in an amount of 30 to 70% by mass, and more preferably 35 to 60% by mass. In particular, it is preferable to select a base polymer mainly composed of a styrene-isoprene-styrene block copolymer (SIS) from the viewpoint of easy compatibility with a fiber assembly and an increase in adhesive strength.

  The hot melt adhesive constituting the first layer 31 of the anti-displacement pressure-sensitive adhesive 30 is a hot melt constituting the second layer 32 from the viewpoint of increasing the plasticity of the adhesive and facilitating migration to a fiber assembly. It is preferable that the content ratio of the plasticizer or the tackifier is larger than the adhesive. Specifically, the hot melt adhesive of the first layer 31 preferably contains 30% by mass or more, and more preferably 40 to 70% by mass of the total of the plasticizer and the tackifier.

  The second layer 32 of the anti-displacement adhesive is not particularly limited as long as it has the above-described relationship with the first layer 31. The type of the second layer 32 depends on an appropriate adhesive force to an adhesive partner such as clothing such as underwear or a disposable diaper. Or choose the amount. From the viewpoint of adhesiveness with the first layer 31, the second layer 32 is made of, for example, a styrene-isoprene-styrene block copolymer (SIS), a styrene-butadiene-styrene block copolymer (SBS), or styrene-ethylene. -It is preferably composed of a hot melt adhesive such as butylene-ethylene copolymer (SEBS).

  In selecting the first layer 31 and the second layer 32, it is inconvenient if the hot-melt adhesive is peeled off between the layers. Therefore, the compatibility between the first layer 31 and the second layer 32 is relatively good. Combinations should be used. In general, the closer the SP value is, the better the compatibility is, but this can be achieved by adding the same kind of rubber component to each of the first layer 31 and the second layer 32.

The fiber aggregate 23 of the non-skin contact surface 3 preferably has a basis weight of 15 to 50 g / m ² from the viewpoints of penetration when the first layer 31 is applied, difficulty of peeling, and the like. More preferably, it is ²⁰ to 35 g / m ² .

In the sanitary napkin of this embodiment, the adhesive force (tack force) of the anti-slip adhesive is preferably from 100 cN to 1500 cN, and more preferably from 300 cN to 600 cN, from the viewpoint of wearability with the underwear and the anti-slip effect.
<Measurement method of tack force>
The tack force is measured using a probe tack test apparatus. This is expressed as strength (cN) when a predetermined SUS probe is brought into contact with the anti-displacement adhesive 30 (second layer 32) under the conditions of a weight of 147 cN / cm ² , a contact time of 5 seconds, and a moving speed of 5 mm / second.

  The application method of the anti-displacement adhesive 30 may be solid coating or pattern coating. Examples of pattern coating patterns include stripe patterns, lattice patterns, checkered patterns, and the like.

The first layer 31 and the second layer 32 are preferably provided in the same location with the second layer 32 larger than the first layer 31 from the viewpoint of not exposing the first layer 31 to the underwear or the like side. From the viewpoint of maintaining the shape of the anti-slipping adhesive 30, it is more preferable to be provided at the same location and the same area. In particular, when the first layer 31 of the anti-displacement adhesive has a higher deformation rate under pressure than the second layer, the hot melt adhesive used for the first layer 31 has an impregnation property to the fiber material at room temperature. In order to be high, it is preferable that the second layer 32 completely covers the first layer 31. As a method of making the above-mentioned size relationship, two layers of the first layer 31 and the second layer 32 are simultaneously applied to a release sheet for protecting the anti-slipping adhesive 30.
In addition, when the cohesion force of the agent of the second layer 32 is sufficiently large, the area of the first layer can be smaller than that of the second layer. When the cohesion force of the agent of the second layer is small, both layers are Preferably they are the same size.

Next, the preferable manufacturing method of the sanitary napkin 1 shown in FIG. 1 is demonstrated.
First, the side cover sheet 40 is joined to both sides of the top sheet 11, and the vertically long absorbent body 12 created in a separate process is provided on the surface opposite to the joint surface of the top sheet 11 with the side cover sheet 40. Deploy. Next, the leakage preventing sheet 21 having the fiber assembly on one side and the other side being the resin film side is arranged so that the resin film side is on the absorber 12 side. In the part extended in the circumference | surroundings of the absorber 12, the said surface sheet 11, the side part cover sheet 40, and the leak-proof sheet | seat 21 are joined by heat seal etc., and the sanitary napkin main body is manufactured.

  Next, the second layer 32 and the second layer 32 and the second layer 32 are placed on the packaging sheet subjected to the peeling treatment by using a coater having two nozzles at one nozzle so that the second layer 32 faces the packaging material sheet. One layer 31 is applied simultaneously to form a laminated adhesive portion. A sanitary napkin 1 (the packaging sheet is omitted) shown in FIG. 1 is manufactured by disposing a packaging sheet having a laminated adhesive portion on the leak-proof sheet 21 which is the non-skin contact surface 3 of the sanitary napkin body.

  In the said manufacturing method, it is necessary to arrange | position the hot-melt-adhesive which comprises a slip prevention adhesive on the leak-proof sheet | seat 21 in a molten state.

  Moreover, after applying the 2nd layer 32 to a packaging sheet, the slip prevention adhesive 30 may apply | coat the 1st layer 31 on it. Alternatively, the first layer 31 may be applied to the non-skin contact surface 3 and the second layer 32 may be applied directly to the non-skin contact surface 3 of the sanitary napkin instead of the peeled packaging sheet. You may laminate | stack the 1st layer 31 and the 2nd layer 32 after apply | coating on a packaging sheet.

The present invention is not limited to the embodiment described above. In the above-described embodiment, the non-slip adhesive having a laminated structure is used at a location provided on the non-skin contact surface where an absorbent layer is present in the thickness direction of the sanitary napkin. For example, the adhesive is provided on both sides for fixing underwear. The anti-slipping adhesive of the wing part of the sanitary napkin may be a non-slipping adhesive having a laminated structure.
In the above-described embodiment, the non-skin contact surface is constituted by a leak-proof sheet. However, the non-skin contact surface is formed by covering the top sheet such as a nonwoven fabric to the bottom of the leak-proof sheet. The form comprised from may be sufficient.

  Moreover, although the anti-slipping adhesive has at least a two-layer structure, a third-layer hot-melt adhesive may be interposed between the two in order to improve the adhesion between the first layer and the second layer.

  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 examples. Prior to Examples and Comparative Examples, preparation of a sanitary napkin will be described.

[Preparation of sanitary napkins]
(1) Leak-proof sheet A moisture-permeable film having a basis weight of 25 g / m ^{2 and} a fiber assembly having a basis weight of 20 g / m ² obtained by stretching a polyethylene resin film containing 50% by mass of calcium carbonate in the longitudinal direction to make fine holes. A hot melt adhesive (composition D described later) was spiral-sprayed at 5 g / m ² on the moisture permeable film side, and the fiber assembly was immediately bonded to prepare a leak-proof sheet. The following three types of fiber aggregates A to C were used.
A: Air-through non-woven fabric (2.2 dtex polyester / polyethylene core-sheath type composite fiber, basis weight 20 g / m ² )
B: Spunbond nonwoven fabric (polypropylene fiber 1.7 dtex, basis weight 20 g / m ² )
C: spunbond-meltblown-spunbond nonwoven fabric (basis weight 15 g / m ² , 1.7 dtex polypropylene fiber basis weight 6.5 g / m ² spunbond, polypropylene fiber basis weight 2 g / m ² meltblown, 1 .7 dtex polypropylene fiber basis weight 6.5 g / m ² spunbond nonwoven)

(2) Top sheet A 2.2 dtex polyester / polyethylene core-sheath type composite fiber was carded and adjusted to a basis weight of 20 g / m ² , and an air-through nonwoven fabric obtained by hot air bonding was used.

(3) Absorber 250 g / m ² of pulp is piled on a tissue paper of 16 g / m ² and cut, and this is further wrapped with a tissue paper having a length of 140 mm, a width of 100 mm, and a basis weight of 16 g / m ^2. It was molded into a rectangle with a length of 140 mm and a width of 60 mm.

(4) Assembly of sanitary napkin 4 g / m ² of hot melt adhesive was applied to the back surface of the top sheet. Further, 7 g / m ² of hot melt adhesive was applied to the resin film side of the leak-proof sheet. The absorber was interposed between both sheets, and the surface sheet and the leak-proof sheet were sealed by heat sealing so as to surround the periphery of the absorber. The outside of the seal part was cut to form a sanitary napkin having a length of 170 mm and a width of 70 mm. The leak-proof sheet was laminated with the resin film facing the absorber side. In addition, the hot-melt-adhesive used for the assembly was the composition D mentioned later.

[Examples 1-3 and Comparative Examples 1-3]
Using a general-purpose hot melt coater, a hot melt adhesive (first layer of anti-displacement adhesive) heated to 180 ° C. was applied to release paper, and immediately thereafter, this hot melt adhesive was applied to the prepared sanitary napkin. It was transferred onto a leak-proof sheet. Next, a hot melt adhesive (second layer of anti-slipping adhesive) heated to 180 ° C. is applied to release paper, and immediately after that, the hot melt adhesive (first layer of anti-slipping adhesive) that has reached room temperature. ). In this way, a sanitary napkin having a laminated structure anti-displacement adhesive was obtained. The first layer and the second layer were thin-film coated, and the coating amount was adjusted to 25 g / m ² each. The application size was adjusted to be 120 mm long and 50 mm wide with respect to the longitudinal direction of the sanitary napkin. Table 1 shows the composition of each hot-melt adhesive for the anti-displacement adhesive used in Examples and Comparative Examples. Table 2 shows combinations of the first layer and the second layer.

  About the napkin of Examples 1-3 and Comparative Examples 1-3, the adhesive residue evaluation of the slip prevention adhesive was performed with the following method. The results are shown in Table 3.

[Adhesive residue evaluation]
Prepare the sample in the same manner as the pressure aging adhesive force described above, except that the roller is not pressed, and pressurize using the same pressing method (stainless steel plate + 1 kg load, 40 ° C., 80% RH environment for 24 hours). went. When the sample is peeled off from the adherend (cotton kanakin No. 1) at a speed of about 500 mm / min in an environment of 40 ° C. and 80% RH, it is visually checked whether the adhesive is dropped or the leakproof sheet is damaged. Confirmed finger touch. Each of the examples and comparative examples was performed three times. The determination was performed as follows.
○: The slip prevention adhesive does not transfer to the adherend, and there is no damage to the leakproof sheet and the adherend.
X: All or part of the anti-slipping adhesive peeled off from the fiber assembly and transferred to the adherend. Or the leak-proof sheet or adherend was damaged.

  As is apparent from the measurement results in Table 3, Examples 1 to 3 showed good results in any case where the fiber assembly of the leak-proof sheet was variously changed. On the other hand, in Comparative Example 1, a part or all of the pressure-sensitive adhesive was peeled off from all the fiber aggregates and transferred to the adherend, and adhesive residue was generated. In Comparative Example 2, the fiber assembly A was good, but adhesive residue was generated in the fiber assemblies B and C. In Comparative Example 3, the pressure-sensitive adhesive was in close contact with the fiber assembly in a layered state, but peeled off within the layer and transferred to the adherend, resulting in adhesive residue.

Example 4
The sanitary napkin was prepared as described above. A hot melt adhesive (second layer of anti-displacement adhesive) is heated to 150 ° C., and a thin film is coated on the release paper so that the coater of Example 1 has a length of 13 cm, a width of 5 cm, and a basis weight of 30 g / m ^2. Worked. After 1 minute or more has passed, a hot melt adhesive (first layer of anti-displacement pressure-sensitive adhesive) heated to 160 ° C. is thinly coated on the second layer with the same shape and the same basis weight, A slip-preventing adhesive was formed. After a lapse of 1 minute or longer, this anti-slipping adhesive was transferred so that the first layer was on the leak-proof sheet side, and a sanitary napkin having a laminated anti-slipping adhesive was obtained. Table 4 shows the composition of each hot-melt pressure-sensitive adhesive in the anti-displacement pressure-sensitive adhesive. Table 5 shows combinations of the first layer and the second layer.

Example 5
In the same manner as in Example 4, the hot melt adhesive (second layer of anti-displacement adhesive) was heated to 160 ° C., and a thin film was formed on the release paper so that the length was 13 cm, the width was 5 cm, and the basis weight was 30 g / m ^2. Coated. Next, a thin film was applied to the hot melt adhesive (first layer of anti-displacement adhesive) heated to 150 ° C. on the leakproof sheet of the sanitary napkin with the same shape and the same basis weight as the second layer. After 1 minute or more has elapsed, after the hot melt adhesive (first layer) has reached approximately room temperature, the second layer coated on the release paper is transferred onto the first layer, and the adhesive for preventing misalignment of the laminated structure A sanitary napkin having was obtained. Table 4 shows the composition of each hot-melt pressure-sensitive adhesive in the anti-displacement pressure-sensitive adhesive. Table 5 shows combinations of the first layer and the second layer.

[Comparative Example 4]
A comparative sanitary napkin was obtained in the same manner as in Example 1 except that the hot melt adhesive was used in the combinations shown in Table 5. The first layer hot melt adhesive was heated to 160 ° C., and the second layer hot melt adhesive was heated to 150 ° C.

[Comparative Examples 5 and 6]
The hot melt adhesive shown in Table 5 was heated to 150 ° C., and a thin film was coated on the release paper by the coater used in Example 1 so that the length was 13 cm, the width was 5 cm, and the basis weight was 30 g / m ² . After a lapse of 1 minute or more, it was transferred onto a sanitary napkin leakage-proof sheet to obtain a sanitary napkin having a single-layer anti-slipping adhesive.

For the hot melt adhesives used in Examples 4 and 5 and Comparative Examples 4 to 6, the rate of increase in adhesive strength was measured. The results are shown in Table 6. The rate of increase in adhesion was measured by the following method. The hot melt adhesive was thin-film coated (solid coated) into a rectangular shape having a width of 3 cm × length of 15 cm and a basis weight of 30 g / m ² . The initial adhesive force and the temporal adhesive force were measured by the method described above, and the increase rate of the adhesive force was calculated from the measured values.

  About Example 4 and 5 and Comparative Examples 4-6, the adhesive residue evaluation of the slip prevention adhesive was performed by the method similar to Example 1. FIG. The results are shown in Table 7.

  As is apparent from the measurement results in Table 7, Examples 4 and 5 showed good results in any case where the fiber assembly of the leak-proof sheet was variously changed. On the other hand, Comparative Examples 4 to 6 were defective in all the fiber assemblies. In Comparative Examples 4 and 5, the anti-displacement adhesive that adhered to the adherend bite into the adherend, resulting in heavy peeling, and when it was forcibly removed, the leak-proof sheet was torn and adhesive remained. In Comparative Example 6, since the anti-slipping adhesive did not bite into the nonwoven fabric of the leak-proof sheet, the anti-slipping adhesive shifted to the adherend side.

It is a perspective view which shows the sanitary napkin as one Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. FIG. 3 is an enlarged cross-sectional view of an anti-slipping adhesive in the cross-sectional view of FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sanitary napkin 2 Skin contact surface 3 Non-skin contact surface 10 Absorbent layer 11 Surface sheet 12 Absorber 20 Liquid impervious layer (leakproof sheet)
30 Anti-slip adhesive 31 First layer of anti-slip adhesive 32 Second layer of anti-slip adhesive 40 Side cover sheet

Claims (9)

An absorbent article comprising a liquid-retaining absorbent layer and a liquid-impermeable layer and provided with a non-slip adhesive on the non-skin contact surface,
The non-skin contact surface is composed of a fiber assembly, and the anti-slipping adhesive composed of a hot melt adhesive is laminated on the first layer on the non-skin contact surface side and the first layer. An absorbent article having a laminated structure with the second layer, wherein the hot melt adhesive constituting the first layer has higher fluidity near the softening point temperature than the hot melt adhesive constituting the second layer.   2. The absorbent article according to claim 1, wherein the hot melt adhesive constituting the first layer has a smaller viscosity increase gradient accompanying the temperature decrease from near the softening point temperature as compared with the hot melt adhesive constituting the second layer.   The first layer of the anti-slip adhesive has a higher adhesive strength with the non-skin contact surface immediately after application (measured when cooled to 20 ° C) one day after application. Absorbent article.   The absorptive article according to claim 2 or 3 in which the hot melt adhesive which constitutes the 1st layer contains 30-65 mass% of base polymers chosen from the copolymer which has olefin as the main ingredients.   The absorbent article according to claim 1, wherein the hot-melt adhesive constituting the first layer has a higher rate of increase in adhesive force under pressure than the hot-melt adhesive constituting the second layer.   The absorbent article according to claim 5, wherein the hot melt adhesive constituting the first layer has a plasticizer or a tackifier content higher than that of the hot melt adhesive constituting the second layer.   The absorbent article according to claim 1, wherein a non-skin contact surface is composed of the liquid impermeable layer, and the liquid impermeable layer is formed of a laminate sheet of a nonwoven fabric and a resin film.   The absorbent article according to claim 1, wherein the joining surface of the first layer and the second layer of the slip-preventing adhesive is outside the non-skin contact surface. The absorbent article according to claim 1, wherein the first layer and the second layer of the slip prevention adhesive are provided at the same location and the same area.