JP2007105185A - Rear surface sheet of absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rear surface sheet of an absorbent article capable of reducing the sound generated when the absorbent article is peeled off the clothes such as shorts; and also to provide an absorbent article, etc. using the same. <P>SOLUTION: The rear surface sheet 3 of the absorbent article has such a structure that a liquid-impermeable sheet 31 and a nonwoven fabric 32 are layered and integrated with each other, and an adhesive layer 6 is disposed on the surface 34 consisting of the nonwoven fabric 32 to be fixed to the clothes. The loss tangent (tanδ) of the liquid-impermeable sheet 31 is 0.2-3.0 when the temperature is 25°C and the frequency is 2,000 Hz. The basis weight of the nonwoven fabric 32 is 5-300 g/m<SP>2</SP>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a back sheet of an absorbent article, an absorbent article using the same, and the like.

  Conventionally, in absorbent articles such as sanitary napkins, panty liners (origami sheets), and incontinence pads, an adhesive layer is provided on the back sheet, and the absorbent article is fixed to clothing such as shorts via the adhesive layer. It is widely done. By fixing to shorts etc. via an adhesive layer, it can fix to an appropriate position easily and can prevent position shift during wearing. However, on the other hand, a sound is generated when the absorbent article is peeled off shorts or the like, which may cause anxiety to a user who does not want others to notice the use or replacement of the absorbent article.

Patent Document 1 describes that the back sheet is made of only a non-woven fabric to make a breathable back sheet and reduce peeling sound.
In addition, Patent Documents 2 and 3 do not indicate a peeling sound when peeling an absorbent article from clothing, but a pressure-sensitive adhesive layer provided on a diaper fastener tape or the like, such as a target tape or the like to which the pressure-sensitive adhesive layer is pressure-bonded. It describes that the sound at the time of peeling from an adherend is reduced by applying a silicone treatment agent (release agent) on the adherend.

JP-A-7-132961 Japanese Patent Laid-Open No. 5-17728 JP-A-5-146467

However, Patent Document 1 does not describe the use of a liquid-impermeable sheet for the back sheet, and the back sheet of Patent Document 1 is liable to cause liquid leakage during use of the absorbent article. There is. In addition, it has been found that when a liquid-impermeable sheet is bonded to a nonwoven fabric and used as a back sheet, the peeling sound is larger than that of a nonwoven fabric alone. Even if a liquid-impermeable sheet is bonded, the problem of peeling sound when peeling from clothing cannot be solved.
The inventions described in Patent Documents 2 and 3 are applied when the pressure-sensitive adhesive layer and the adherend to which the pressure-sensitive adhesive layer is bonded are present in one article, and the absorbent article is peeled from the undergarment. It is virtually impossible to apply a silicone treatment agent (peeling agent) to unspecified undergarments in order to reduce the peeling sound.

  Accordingly, an object of the present invention is to provide a back sheet that can reduce sound when the absorbent article is peeled off from clothing such as shorts, and an absorbent article and the like using the back sheet.

The present invention has a structure in which a liquid-impermeable sheet and a non-woven fabric are laminated and integrated, and a pressure-sensitive adhesive layer for fixing to a garment is provided on a surface made of the non-woven fabric. The liquid-impermeable sheet has a loss tangent (tan δ) at a temperature of 25 ° C. and a frequency of 2000 Hz of 0.2 to 3.0, and the nonwoven fabric has a basis weight of 5 to 300 g / m ² . The said objective is achieved by providing the back surface sheet of an absorbent article.

  Further, the present invention is an absorbent article comprising the absorbent layer and the back sheet according to any one of claims 1 to 4, wherein an adhesive layer is provided on the surface of the back sheet made of the nonwoven fabric, The said adhesive layer provides the absorbent article currently formed using the hot-melt-type adhesive containing 20-45 mass% of softening agents.

  Further, the present invention provides an absorbent article comprising the absorbent layer and the back sheet according to any one of claims 1 to 4 and having an adhesive layer on the surface made of the nonwoven fabric in the back sheet. A package of an absorbent article, an absorbent layer, and an absorbent layer according to any one of claims 1 to 4, wherein the package is housed in a packaging material having a display recommended to be used in combination with shorts made of a cloth made of tengu. An absorbent article set comprising a combination of an absorbent article provided with an adhesive layer on the surface made of the nonwoven fabric of the back sheet and shorts made of a cloth with a crotch part. It is to provide.

According to the back sheet of the absorbent article of the present invention, it is possible to reduce the sound when the absorbent article is peeled off from clothing such as shorts.
According to the absorbent article of the present invention, it is possible to further reduce the sound when the absorbent article is peeled off from clothing such as shorts.
According to the package of absorbent articles and the absorbent article set of the present invention, it is possible to provide a combination of absorbent articles and shorts that is excellent in the sound reduction effect when the absorbent article is peeled off from the shorts.

  Hereinafter, the present invention will be described in detail based on preferred embodiments thereof.

  As shown in FIG. 1, the back sheet 3 of the absorbent article according to an embodiment of the present invention has a structure in which a liquid-impermeable sheet 31 and a nonwoven fabric 32 are laminated and integrated. When the back sheet 3 is incorporated in an absorbent article such as a sanitary napkin, as shown in FIG. 1, an adhesive layer for fixing to a garment such as shorts on a surface 34 made of a nonwoven fabric of the back sheet 3. 6 is provided.

  The liquid-impermeable sheet 31 used for the back sheet has a loss tangent (tan δ, hereinafter, also simply referred to as “tan δ”) at a temperature of 25 ° C. and a frequency of 2000 Hz of 0.2 to 3.0. If tan δ is less than 0.2, the effect of reducing sound when the absorbent article is peeled off from clothing cannot be sufficiently obtained. If tan δ is more than 3.0, sufficient strength to be used as a back sheet. It becomes difficult to ensure.

The reason for defining tan δ at a frequency of 2000 Hz is as follows. That is, when the state of the interface between the adhesive layer provided on the back sheet and the shorts when the absorbent article is peeled off from the clothing such as shorts is observed, the distance between the back sheet and the shorts increases. Along with that, a part of the adhesive is stretched between the back sheet and the shorts, and when part of the stretched adhesive leaves the shorts, it is found that the back sheet is vibrated to generate sound. did. When the frequency component of the sound (hereinafter also referred to as peeling sound) was analyzed using a sound level meter (“Normal Sound Level Meter NL-20” and “Small FFT Analyzer SA-78” manufactured by Rion Co., Ltd.), it was around 2000 Hz. The sound component was particularly large. From this, tan δ at 2000 Hz is high, so in the present invention, the vibration energy generated when the absorbent article is peeled off from the garment can be efficiently converted into thermal energy, and the peeling sound can be reduced efficiently. This is because it is estimated that.

  The liquid-impermeable sheet has a tan δ at a temperature of 25 ° C. and a frequency of 2000 Hz of 0.2 to 2.0 from the viewpoint of further reducing sound and securing strength when the absorbent article is peeled from the clothing. Is preferable, and it is more preferable that it is 0.5-1.0.

The liquid-impermeable sheet is not particularly limited as long as tan δ at a temperature of 25 ° C. and a frequency of 2000 Hz is 0.2 to 3.0 in dynamic viscoelasticity measurement, but is thermoplastic from the viewpoint of molding processability. It is preferable that an elastomer is contained (including a thermoplastic elastomer having a mass of 100% by mass).
Examples of the thermoplastic elastomer include styrene elastomers, olefin elastomers, urethane elastomers, vinyl chloride elastomers, polyester elastomers, polyamide elastomers, and the like.

The styrene elastomer is an AB type or ABA type block copolymer having a styrene component (A) and a rubber component (B), and the content (copolymerization ratio) of the styrene component (A) is 5 -80% by weight, for example, styrene-butadiene diblock copolymer and hydrogenated product thereof, styrene-butadiene-styrene triblock copolymer and hydrogenated product thereof, styrene-isoprene diblock copolymer and Hydrogenated product thereof, styrene-isoprene-styrene triblock copolymer and hydrogenated product thereof, styrene-vinylisoprene block copolymer and hydrogenated product thereof, styrene-vinylisoprene-styrene triblock copolymer and water thereof Additives and the like.
Examples of the olefin-based elastomer include a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms, a simple blend of ethylene-propylene rubber and polyethylene and polypropylene, and only a part of ethylene-propylene rubber which is a soft segment. Cross-linked type products in which polyethylene and polypropylene are combined, and cross-linked type products in which ethylene-propylene rubber is completely cross-linked and dispersed in polyethylene and polypropylene are exemplified.

  Examples of the urethane elastomer include those having various structures, such as Kuraray U manufactured by Kuraray Co., Ltd., Ufine manufactured by Asahi Glass Co., Ltd., Esten manufactured by Kyowa Hakko Co., Ltd. REZAMIN P manufactured by DIC Bayer Polymer Co., Ltd., Pandex, Desmopan, Milactolan manufactured by Nihon Milactolan, Nisshinbo Mobilon manufactured by Nisshinbo Co., Ltd., and the like.

  Examples of the vinyl chloride elastomer include a high polymerization type (weight average molecular weight = 4000 or more), a crosslinking type, and a copolymer type. As the polyester-based elastomer, a polyester / polyether type product using an aliphatic polyether having 2 to 20 carbon atoms and a polymerization degree of 1 to 50 for the soft segment, and a weight average molecular weight of 50 to 5000 for the soft segment. Examples include polyester / polyester type products using aliphatic polyester. As the polyamide-based elastomer, a polyether amide type product using a polyether having 2 to 20 carbon atoms and a polymerization degree of 1 to 50 for the soft segment, and 2 to 20 carbon atoms and a polymerization degree of 1 for the soft segment. A polyether polyester amide type product using a polyether having ˜50 and a polyester having a weight average molecular weight of 50 to 5,000 is mentioned.

  The above-mentioned various thermoplastic elastomers can be used as a material for a liquid-impermeable sheet alone or in combination of two or more. Moreover, only a thermoplastic elastomer may be used, it may be used by blending with a thermoplastic resin other than the thermoplastic elastomer, or an inorganic filler or a plasticizer may be mixed and used. Examples of the thermoplastic resin other than the thermoplastic elastomer include polyolefin resins such as polyethylene and polypropylene, ethylene-vinyl acetate copolymer (EVA) and its hydrolyzate, ethylene-methacrylic acid copolymer (EMMA), and ethylene-acrylic. Examples thereof include modified polyethylene such as an acid acid copolymer (EEA). Examples of the plasticizer include paraffin oil and paraffin wax. These thermoplastic resins and plasticizers can also be used singly or in combination of two or more.

  The content of the thermoplastic elastomer in the liquid-impermeable sheet is preferably 10% by mass or more, more preferably 30 to 100% by mass, and still more preferably 50 to 100% by mass from the viewpoint of the peeling sound reduction effect. %. The content of the thermoplastic elastomer in the case where a component other than the polymer component such as an inorganic filler is blended is preferably such that the content in the polymer component excluding the inorganic filler is within the above range.

The liquid-impermeable sheet may contain one or more thermoplastic elastomers selected from the group consisting of styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, and urethane-based elastomers from the viewpoint of moldability and the like. Preferably, the content of these thermoplastic elastomers (the total content when 2 or more types are contained) is liquid impermeable in the liquid-impermeable sheet (when components other than the polymer component such as inorganic filler are included). The polymer component of the permeable sheet) is preferably 50% by mass or more.
The liquid-impermeable sheet contains a styrene-based thermoplastic elastomer from the viewpoint of reducing peeling noise, moldability, and availability, and the content of the styrene-based thermoplastic elastomer is the total polymer in the liquid-impermeable sheet. More preferably, it is 50 mass% or more.

  The method for producing the liquid-impermeable sheet is not particularly limited, and examples thereof include a T-die method and an inflation method. The thickness of the liquid-impermeable sheet is, for example, 5 to 100 μm, preferably 10 to 50 μm, more preferably 15 to 30 μm from the viewpoint of moldability and strength.

The nonwoven fabric 32 used for the back sheet has a basis weight of 5 to 300 g / m ² . As the nonwoven fabric 32, as long as the basis weight is 5 to 300 g / m ² , the material and the production method are not particularly limited, but a nonwoven fabric using organic fibers is preferable from the viewpoint of touch. Examples of the organic fibers include natural fibers such as cotton, hemp, and wool, rayon, cupra recycled fibers, acetate, semi-synthetic fibers of promix, nylon, polyester, acrylic, vinylon, polyvinyl chloride, vinylidene, and polyolefin. And synthetic fibers such as polyurethane, polyclar, fluorocarbon, and noboid. Among these, polyolefin fibers or polyester fibers based on ethylene, propylene, and butene are preferable from the viewpoints of feel, moldability, and price.
Also, from the balance between the feel and strength of the nonwoven fabric, a composite fiber such as a blend of two or more kinds of fibers, a core / sheath, a side-by-side, a sea island, or a split is preferably used.

Moreover, it is preferable that the manufacturing method is a thermal bond method, a felt method, a stitch method, a needle punch method, a spun lace method, a spun bond method, a net method, and a melt blow method from the viewpoint of touch.
The fiber diameter of the constituent fibers of the nonwoven fabric is preferably 30 μm or less, more preferably 15 μm or less, still more preferably 8 μm or less from the viewpoint of feel. Although the lower limit of the constituent fiber diameter of the nonwoven fabric is not particularly limited, it is, for example, 0.5 μm from the viewpoint of productivity and availability.

The basis weight of the nonwoven fabric 32 is 5 to 300 g / m ² from the viewpoint of reduction of peeling sound and feel, but from the viewpoint of feel and price, preferably 10 to 70 g / m ² , more preferably 15 to 50 g / m ² . ² .
Moreover, it is preferable that the thickness of the nonwoven fabric 32 is 30-1000 micrometers from a viewpoint of the further reduction of peeling sound, More preferably, it is 70-900 micrometers from the balance of peeling sound reduction efficiency and fitting property at the time of mounting, More preferably The thickness is 100 to 800 μm, particularly preferably 150 to 700 μm.
The thickness of the non-woven fabric 32 is a value obtained by applying a load of 0.5 g / cm ^{2 to} the non-woven fabric and determining the thickness at that time using a laser displacement meter (LK-2110 manufactured by Keyence Corporation).

As a method of integrating the liquid-impermeable sheet 31 and the nonwoven fabric 32, a method of bonding them with an adhesive, a method of bonding by heat sealing, a method of bonding by ultrasonic sealing, a method of bonding by high-frequency sealing, etc. These various known methods can be used. From the viewpoint of reducing the amount of material used, heat sealing, ultrasonic sealing, and high frequency sealing are preferable, and heat sealing is more preferable from the viewpoint of operability.
The bonding between the liquid-impermeable sheet 31 and the nonwoven fabric 32 may be entirely bonded or partially bonded, but is preferably partially bonded from the viewpoint of touch.
As a seal pattern in the case of joining between the liquid-impermeable sheet 31 and the nonwoven fabric 32 by heat sealing or the like, a dot shape, a rod shape, a lattice shape, or the like may be used.

The thickness of the back sheet 3 in which the liquid-impermeable sheet 31 and the nonwoven fabric 32 are integrated is preferably 35 to 1100 μm from the viewpoint of reducing the peeling noise, and the balance between the peeling noise reduction effect and the fit and strength. From this viewpoint, it is more preferably 75 to 950 μm, still more preferably 110 to 830 μm, particularly preferably 165 to 730 μm or 150 to 700 μm.
The thickness of the back sheet is also a value obtained by applying a load of 0.5 g / cm ² to the back sheet and determining the thickness at that time with a laser displacement meter (LK-2110 manufactured by Keyence Corporation).

  The back sheet 3 of the absorbent article according to the present embodiment has a pressure-sensitive adhesive layer 6 provided on a surface 34 (hereinafter also referred to as a clothing contact surface) made of a non-woven fabric 32 as in the sanitary napkin shown in FIG. It is preferably used as the back sheet 3 of the absorbent article.

  The sanitary napkin 1 shown in FIG. 2 has a structure in which an absorbent layer 5 composed of a liquid-permeable top sheet 2 and a liquid-retaining absorbent 4 and a liquid-impermeable back sheet 3 are integrated in a laminated state. A pressure-sensitive adhesive is applied to the garment contact surface of the back sheet 3 to form a pressure-sensitive adhesive layer 6 for fixing the napkin 1 to a garment (wearing tool) such as shorts. The sanitary napkin 1 shown in FIG. 2 has a shape that is long in the same direction as the wearer's front-rear direction when worn, and the pressure-sensitive adhesive layer 6 has a rectangular shape with the longitudinal direction of the napkin 1 as the long side. It is formed and continuously formed over a length of about 50 to 95% with respect to the total length in the napkin longitudinal direction.

As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 6, various conventionally known pressure-sensitive adhesives can be used, but a hot-melt type pressure-sensitive adhesive is preferably used from the viewpoint of coating workability.
As the hot-melt type pressure-sensitive adhesive, for example, those mainly composed of a styrene block polymer, a tackifier and a softener are preferably used.
Examples of the styrenic block polymer include styrene-butadiene diblock copolymers and hydrogenated products thereof, styrene-butadiene-styrene triblock copolymers and hydrogenated products thereof, styrene-isoprene block copolymers, and hydrogenated products thereof. Products, styrene-isoprene-styrene triblock copolymers and hydrogenated products thereof. From the viewpoint of adhesive strength, these styrenic block polymers preferably have a styrene portion having a molecular weight of 5,000 to 20,000 and a rubber portion having a molecular weight of 25,000 to 70,000. As the tackifier, a polyterpene resin which is a copolymer of a C5 petroleum resin, a C9 petroleum resin, α-pinene, β-pinene or dipentene having a softening point of 10 ° C. or less and a number average molecular weight of 400 to 2000 , Rosin resins, or hydrogenated products thereof. Examples of the softener include process oil having a softening point of 10 ° C. or less and a number average molecular weight of 150 to 700, various plasticizers, polybutene, and liquid resin.
These styrenic block polymers, tackifiers and softeners can be used singly or in combination of two or more.

The hot-melt adhesive mainly composed of a styrene block polymer, a tackifier, and a softening agent contains 150 to 200 parts by mass of a resin as a tackifier with respect to 100 parts by mass of the styrene block polymer. The content of the softener is preferably 20 to 45% by mass with respect to the total amount of the pressure-sensitive adhesive. The content of the softening agent is preferably 20 to 45% by mass, more preferably 24 to 38% by mass, and still more preferably 28 to 32% with respect to the total amount of the adhesive, from the viewpoint of reducing peeling noise and adhesiveness to shorts and the like. % By mass. When the content of the softening agent is 28 to 32% by mass, the balance between the difficulty of displacement at the time of wearing and the reduction of peeling noise is particularly good. The basis weight of the pressure-sensitive adhesive layer can be 10 to 100 g / m ^2, and preferably 30 to 60 g / m ² .
Moreover, a stabilizer etc. can also be mix | blended besides a styrene-type block polymer, tackifier resin, and a softening agent.

When the back surface sheet of the present invention is used as a back sheet of an absorbent article with a pressure-sensitive adhesive layer formed on a surface made of a nonwoven fabric, an excellent peeling noise reduction effect is obtained.
That is, as described above, the peeling sound when peeling absorbent articles from clothing such as shorts is struck against the back sheet when a part of the stretched adhesive peels off the shorts and returns to its original state. The surface of the back sheet that comes into contact with the pressure-sensitive adhesive layer is made of non-woven fabric, so that the substantial area of the opponent when the pressure-sensitive adhesive layer is peeled off from clothing such as shorts and the back sheet is struck is reduced. Therefore, there is little vibration generated in the nonwoven fabric. In addition, as described above, by using a liquid-impermeable sheet having a high tan δ at 2000 Hz, vibration transmitted from the nonwoven fabric to the liquid-impermeable sheet is efficiently converted into heat energy in the liquid-impermeable sheet. It is also considered that the generation of sound from the liquid-impermeable sheet was reduced, which greatly contributed to the reduction of peeling sound.
Moreover, since the back surface sheet of this invention uses the nonwoven fabric on the outer side which touches skin, a touch is also favorable.

  The absorbent article using the back sheet of the present invention or the absorbent article according to the present invention is usually a pressure-sensitive adhesive layer provided on the clothing contact surface of the back sheet or clothing such as shorts via the provided pressure-sensitive adhesive layer. And is attached to the wearer in that state. The back sheet and absorbent article of the present invention have an effect of reducing peeling sound regardless of the material of clothing, and are used by being fixed to clothing made of materials such as knitted knitted fabric, milled fabric, smooth fabric, tricot fabric, etc. However, when the crotch portion is used in combination with a shorts made of a cloth made of a knitted cloth, in particular, a cotton knitted cloth, the peeling sound is further reduced.

Absorbent articles such as sanitary napkins, panty liners (origami sheets), and incontinence pads are generally distributed (commercially available) separately from shorts. From the viewpoint of being able to be used in combination with shorts, the absorbent article using the back sheet of the present invention or the absorbent article according to the present invention is used in combination with shorts whose crotch portion is made of a woven fabric. It is preferable that the product is stored in a packaging material (a packaging bag made of a resin film material, a box made of paper, etc.) with a display recommending this and distributed (commercially available) as a package of absorbent articles. A display that recommends the crotch part to be used in combination with shorts made of woven cloth is a display that identifies such shorts by product name or product number and recommends the use of shorts such as product name or product number. There may be.
Alternatively, the absorbent article using the back sheet of the present invention or the absorbent article according to the present invention is combined with shorts made of a cloth with a crotch knitted fabric, and distributed as an absorbent article set ( (Commercially available etc.).

  In addition to sanitary napkins, the absorbent article in the present invention may be panty liners (origami sheets), incontinence pads, and the like. The configuration of the absorbent article other than the back sheet is not particularly limited, and can be the same as a known one. For example, non-woven fabrics or apertured films produced by various manufacturing methods can be used as the surface sheet, and the absorbent body can be a fiber aggregate of hydrophilic fibers or a combination of this and a polymer water-absorbing polymer. Can do. Further, the absorbent article may or may not have a so-called wing, and both side portions of the top sheet are not wound between the absorbent body 4 and the back sheet 3. In addition, the outer periphery of the absorber 4 may be joined to the back sheet 3.

  The shape of the pressure-sensitive adhesive layer in a plan view can also be in an appropriate form, and can be in the same form as conventionally known various forms. For example, instead of the rectangular pressure-sensitive adhesive layer described above, a pressure-sensitive adhesive layer having an elliptical shape, a circular shape, a rhombus shape, a square shape, a pentagonal shape, a hexagonal shape, or the like can be provided. Further, a plurality of pressure-sensitive adhesive layers may be formed separated in the width direction and / or the longitudinal direction of the napkin, for example, a belt-like pressure-sensitive adhesive layer extending in the width direction of the napkin and / or a belt-like pressure-sensitive adhesive layer extending in the longitudinal direction. A large number of agent layers may be provided, and the adhesive layer may be dispersed and arranged in a dot shape (scatter pattern) or a checkered pattern.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not restrict | limited at all by the following Examples.

[Constituent materials for back sheet and adhesive layer]
1. Liquid impervious sheet (resin film)
Seven types of liquid-impermeable sheets (1A to 1G) shown in Table 1 were prepared and used for the test. Each sheet was obtained by charging the resin shown in the resin column of Table 1 into a T-die extruder and melt-molding it at a temperature range of a die temperature of 180 to 300 ° C.
Incidentally, Hibler 7350 is an AB type styrene elastomer having a styrene content of 50% by mass, and Hibler 7311S is a styrene content of 12% by mass.

The tan δ of each liquid-impermeable sheet was determined as follows.
Each liquid-impermeable sheet was cut into a width of 5 mm and a length of 20 mm, and the dynamic viscoelasticity of the obtained sample was measured with a dynamic viscoelasticity measuring apparatus (DMS6100 manufactured by SII NanoTechnology Co., Ltd.). . The measurement conditions are as follows. The measurement results are shown in Table 1.
Deformation mode: Film shear mode Measurement frequency: 0.5, 1, 2, 5, 10 Hz
Measurement temperature range: -130 ° C to + 120 ° C
Temperature increase rate: 2 ° C / min Atmosphere: Nitrogen gas 200mL / min From the master curve (created by SII Nano Technology Co., Ltd. Master Curve Analysis Program) created by the temperature-time conversion rule using the obtained measurement results E ′ and tan δ at 2000 Hz were derived.

In addition, when the moisture permeability (JIS Z 0208) of the seven types of liquid-impermeable sheets obtained was measured, all of them were less than 0.02 g / 100 cm ² · h, and substantially no breathability. there were.

2. Nonwoven fabric Five types of nonwoven fabrics (2A to 2E) shown in Table 2 were used for the test.

3. Adhesive composition for forming an adhesive layer As a resin, a styrene-butadiene copolymer (manufactured by Firestone, trade name: Stereon 840) and as a tackifier, an aromatic terpene adhesive (manufactured by Arizona Chemical, trade name: Zonac105) The white mineral oil (reagent) was used as a softening agent, and these were blended in the two blending ratios shown in Table 3 to prepare pressure-sensitive adhesive compositions (3A, 3B) shown in Table 3.

[Example 1]
The nonwoven fabric 2A in Table 2 was laminated on the liquid-impermeable sheet 1A in Table 1, and these were integrated by heat sealing all over to obtain a back sheet.
The thickness of the back sheet was applied to the back sheet with a load of 0.5 g / cm ² , and the thickness at that time was determined with a laser displacement meter (LK-2110 manufactured by Keyence Corporation), and then a sanitary napkin was manufactured. . The back sheet is disposed such that the liquid-impermeable sheet side surface faces the absorber side, and the non-woven fabric side surface faces the opposite side of the absorbent body. Product 3B was applied to form an adhesive layer.

The surface sheet is made of an airlaid nonwoven fabric (basis weight: 25 g / m ² ) made of a composite fiber having a core-polyethylene terephthalate core and a sheath-polyethylene sheath. The body was wrapped with tissue paper. The basis weight of the tissue paper was 15 g / m ² , and the basis weight of the entire absorbent body was 700 g / m ² . The mass ratio of fluff pulp to superabsorbent polymer was 3.5: 1.

[Examples 2 to 10]
A sanitary napkin was produced in the same manner as in Example 1 except that the liquid-impermeable sheet, the nonwoven fabric, and the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer were those shown in Table 4.

[Comparative Example 1]
A sanitary napkin was produced in the same manner as in Example 1 except that only the liquid-impermeable sheet (polyethylene film) 1G in Table 1 was used as the back sheet.

[Comparative Examples 2 to 4]
A sanitary napkin was produced in the same manner as in Example 1 except that the liquid-impermeable sheet, the nonwoven fabric, and the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer were those shown in Table 4.

<Evaluation method>
(1) Peeling noise reduction effect The napkin obtained in the example and the comparative example is fixed to the shorts of the knitted sheet or tricot knitting (see Table 4), and then the peeling sound when the napkin is peeled off by the following procedure. It was measured. First, using a roller having a mass of 2 kg (diameter 60 mm, width 65 mm), the roller was reciprocated once to press the napkin to the shorts crotch. Next, in the silent room, 10 panelists evaluated the magnitude of the sound generated when the napkin was quickly removed from the shorts by hand. When all the panelists answered that the peeling sound was reduced with respect to Comparative Example 1, “◎”, when 8 to 9 people answered that the peeling sound was reduced, “◯”, and 5 to 7 people were peeling sound. Was evaluated as “△”, and when four or less people answered that the peeling sound was reduced, it was evaluated as “x”. In this evaluation, it was judged that “Δ” or more is effective.

(2) Feel About the back sheets used for the manufacture of sanitary napkins in the examples and comparative examples, the feel when touched by hand was evaluated by 10 panelists in the state where no adhesive layer was provided.
When all the panelists answered that the touch was good with respect to that of Comparative Example 1, “◎”, when 8 to 9 people answered that the touch was good, “○”, and 5 to 7 people said that the touch was good The case where the answer was "△" and the case where four or less people answered that the touch was good were evaluated as "X". In this evaluation, it was judged that “Δ” or more is effective.

(3) Fit property The sanitary napkin produced by the Example and the comparative example was actually mounted on 10 panelists, and the fit property was evaluated. When all the panelists answered that the fit was good compared to Comparative Example 4, "◎", when 8-9 answered that the fit was good, "○", 5-7 were fit The case where the answer was good was evaluated as “△”, and the case where four or less people answered that the fit was good was evaluated as “x”. In this evaluation, it was judged that “Δ” or more is effective.

From the results shown in Table 4, in the sanitary napkin (back sheet) of the example, the peeling sound is reduced compared to Comparative Example 1 in which the back sheet is composed only of the liquid-impermeable sheet, and the touch is also good. It turns out that it is. On the other hand, in Comparative Example 2 using a polyethylene film having a tan δ of less than 0.2, an effect of reducing peeling sound was not recognized. Further, Comparative Example 3 using a nonwoven fabric with a basis weight of 3.5 g / m ² also shows no effect of reducing the peeling noise, and Comparative Example 4 using a nonwoven fabric with a basis weight of 370 g / m ² has poor fit. Met.

FIG. 1 is a partially enlarged cross-sectional view showing a part of the back sheet according to the present invention as a state in which a pressure-sensitive adhesive layer is provided on the non-woven fabric side. FIG. 2 is a schematic cross-sectional view showing a cross-section in the width direction of a sanitary napkin that is an example of an absorbent article according to the present invention.

Explanation of symbols

1 Sanitary napkin (absorbent article)
2 Surface sheet 3 Back sheet 31 Liquid impermeable sheet 32 Non-woven fabric 34 Non-woven fabric side surface 4 Absorber 5 Absorbing layer 6 Adhesive layer

Claims (7)

A liquid-impermeable sheet and a nonwoven fabric are laminated and integrated, and a pressure-sensitive adhesive layer for fixing to clothing is provided on the surface made of the nonwoven fabric.
The liquid-impermeable sheet has a loss tangent (tan δ) at a temperature of 25 ° C. and a frequency of 2000 Hz of 0.2 to 3.0,
The said nonwoven fabric is a back surface sheet of an absorbent article whose basic weight is 5-300 g / m < ² >.   The liquid-impermeable sheet contains one or more thermoplastic elastomers selected from the group consisting of styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, and urethane-based elastomers, and the content of the thermoplastic elastomer is: The back sheet of an absorbent article according to claim 1 or 2, wherein the content is 50% by mass or more in the liquid-impermeable sheet.   The absorbent article according to claim 2, wherein the liquid-impermeable sheet contains a styrene-based thermoplastic elastomer, and the content of the styrene-based thermoplastic elastomer is 50% by mass or more in the liquid-impermeable sheet. Back sheet.   The thickness of the said back sheet is 150-700 micrometers, The back sheet of the absorbent article in any one of Claims 1-3. An absorbent article comprising the absorbent layer and the back sheet according to any one of claims 1 to 4, wherein an adhesive layer is provided on the surface of the back sheet made of the nonwoven fabric,
The absorbent article in which the said adhesive layer is formed using the hot-melt-type adhesive containing 20-45 mass% of softening agents.   An absorbent article comprising the absorbent layer and the back sheet according to any one of claims 1 to 4, wherein an adhesive layer is provided on the surface of the back sheet made of the nonwoven fabric, and the crotch part is made from a cloth of a knitted sheet. A package for absorbent articles, which is housed in a packaging material having a display recommended to be used in combination with shorts. An absorbent article comprising the absorbent layer and the back sheet according to any one of claims 1 to 4, wherein an adhesive layer is provided on the surface of the back sheet made of the nonwoven fabric, and the crotch part is made of a cloth made from a knitted sheet. Absorbent article set that combines with shorts.

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