TWI687564B - Spunbonded non-woven fabric, sheet, and absorbent article - Google Patents

Abstract

Spunbonded non-woven fabric is made from fiber of a thermoplastic resin and has a predetermined water resistance which has, when the anti-water pressure thereof is measured in a conformity with ISO811, a second anti-water pressure measured for the second time or subsequent to the second time degrading by a predetermined pressure or lower from the first anti-water pressure measured for the first time. The first anti-water pressure is equal to or more than 160 mmH₂O and the predetermined pressure is equal to or less than 30 mmH₂O.

Description

Spinning bonded non-woven fabrics, sheets and absorbent articles

This case concerns absorbent articles such as paper diapers, sanitary napkins, the preferred sheets used therefor, and the preferred spunbonded nonwoven fabrics used therefor.

In the conventional absorbent articles, in addition to an absorbent pad that can absorb urine, menstrual blood, and other liquids excreted by the wearer, a water-resistant sheet that can withstand a predetermined water pressure is also provided. By designing the three-dimensional pleats and the outer edge of the sheet, the sheet can suppress the leakage of absorbent articles.

One of the above water-resistant sheets uses a melt-blown non-woven fabric. Although the melt-blown non-woven fabric has small openings, it is difficult for water to penetrate, but the strength is low. On the other hand, the spun-bonded non-woven fabric, which is one of the other non-woven fabrics, has a larger opening than a melt-blown non-woven fabric, so that moisture easily penetrates, but the strength is higher.

Therefore, there have been developed water-resistant sheets that use spunbonded nonwovens to reinforce meltblown nonwovens. For example, as shown in FIG. 3A, by sandwiching the melt-blown non-woven fabric 42 with two layers of spun-bonded non-woven fabrics 41, 41, as shown in FIG. 3B, the SMS non-woven fabric reinforced by the spun-bonded non-woven fabrics 41, 41 is reinforced by spinning 40. Research on the use of water-resistant sheets (refer to Patent Document 1).

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-66308

However, if the melt-blown non-woven layer of the SMS non-woven fabric is damaged, the water pressure resistance of the sheet will be greatly reduced due to the opening of the spun bonded non-woven layer. Therefore, if high water pressure is repeatedly applied to the water-resistant sheet using the SMS nonwoven fabric in the absorbent article, there is a possibility that liquid leakage cannot be suppressed. Therefore, there is room for improvement in terms of ensuring the comfort of the wearer.

The absorbent article of this case, the preferred sheet used therein, and the preferred spunbonded nonwoven fabric used therefor have been completed in view of the above problems, and one of the purposes is to ensure the comfort of the wearer.

In addition, not limited to the so-called purpose here, the actions and effects derived from the configurations shown in the "embodiments" described later, and the actions and effects that cannot be obtained by the conventional technology, can be attributed to other purposes in this case.

The inventors of the present case have intensively studied to solve the above-mentioned problems, and as a result, not from the conventional viewpoint of making the meltblown nonwoven fabric used in the sheet water-resistant, but from the new viewpoint of making the spunbonded nonwoven fabric used in the sheet have a predetermined water resistance I set out to find an absorbent article that would ensure the comfort of the wearer.

(1) The spunbonded non-woven fabric disclosed herein uses thermoplastic resin fibers. The spunbonded nonwoven fabric has a predetermined water resistance below the predetermined pressure when the second water pressure resistance measured after the second time is lower than the first water pressure resistance measured the first time when the water pressure resistance is repeatedly measured according to ISO811 Sex. In addition, the first water pressure resistance is 160 mmH ₂ O or more, and the predetermined pressure is 30 mmH ₂ O or less. In addition, the above-mentioned predetermined water resistance refers to the physical properties that continuously satisfy the water pressure resistance required for the sheet.

(2) The average fineness of the above fibers is preferably 0.1 to 1.0 Danny, and the basis weight of the spunbonded nonwoven fabric is preferably 8 to 20 g/m ² .

(3) The thermoplastic resin is preferably a polyolefin resin containing polypropylene.

(4) The above polyolefin resin preferably satisfies the following <characteristic a> to <characteristic h>: <characteristic a> meso-five unit composition rate is 30 to 80 mole %; <characteristic b> When the racemic five-unit component rate is set to "A" and the racemic five-unit component rate is set to "B", the inequality I "B/(1-A)≦0.1" is satisfied; <characteristic c> racemic The meso-racemic meso-five-unit component rate is greater than 2.5 mole %; <characteristic d> set the meso-trime unit rate to "C", and the meso-triso unit rate to "C""D", when the three-unit component ratio is set to "E", satisfy the inequality II "C×D/E ² ≦2.0";<Characteristice> Weight average molecular weight system is 10000~200000; <Characteristic f> The above weight average molecular weight When set to "Mw" and the number average molecular weight is set to "Mn", satisfy the inequality III ""Mw/Mn≦4";<Characteristicg> The amount of extract using boiling diethyl ether is 0 to 10% by mass; <Characteristic h >The low-crystalline polyolefin resin satisfying the above <characteristic a> to <characteristic g> is 5 to 50% by mass based on the total solid content.

(5) The sheet disclosed herein preferably contains the above-mentioned spunbonded nonwoven fabric, but does not contain meltblown nonwoven fabric. That is, the sheet is preferably composed only of the above-mentioned spunbonded nonwoven fabric.

(6) The sheet material preferably has an area ratio of 5 to 25% of the embossed portion where the fibers are fused to each other.

(7) The sheet is preferably overlapped by two or more sheets.

(8) Furthermore, the absorbent article disclosed here is preferably arranged on the body side with the above-mentioned sheet.

(9) Furthermore, it is preferable that the absorbent article is used for the three-dimensional pleats that are erected on the body side by using the sheet.

According to the absorbent article of the present invention, by allowing the spunbonded nonwoven fabric used in the sheet to have a predetermined water resistance, it is possible to suppress the liquid discharged from the wearer from penetrating through the sheet, thereby suppressing the leakage of liquid. Therefore, the comfort of the wearer can be ensured.

1‧‧‧ Lower crotch

2‧‧‧pattern

10‧‧‧absorber

11‧‧‧Wrapped tablets

12‧‧‧absorption pad

13‧‧‧Top slice

14‧‧‧Back sheet

15‧‧‧ Cover sheet

15c‧‧‧Outside Sheet Department

20‧‧‧Side (sheet)

20a‧‧‧Inner Wall Sheet Department

20b‧‧‧External wall sheet department

20c‧‧‧Outside Sheet Department

21‧‧‧ Three-dimensional broken pleats

22‧‧‧Legs

31‧‧‧The first silk rubber

32‧‧‧Second silk rubber

40‧‧‧SMS non-woven

41‧‧‧Spun bonded non-woven fabric (layer)

42‧‧‧meltblown nonwoven (layer)

Fig. 1 is a partial cross-sectional view of a paper diaper (absorbent article) cut at the lower part of the crotch.

Fig. 2 is a schematic schematic perspective view of a sheet of spunbonded nonwoven fabric.

In FIG. 3, a schematic schematic perspective view of sheets of the SMS nonwoven fabrics of FIGS. 3A and 3B, the layers of the nonwoven fabrics of FIG. 3A are separated from each other, and the nonwoven fabrics of FIG. 3B are stacked.

The absorbent article of the embodiment will be described with reference to the drawings. In addition, the embodiment shown below is only an illustration at best, and it is not intended to exclude the application of various changes and techniques not explicitly shown in the following embodiment. Each configuration of the present embodiment can be variously changed without departing from the scope of the subject matter. In addition, they may be selected according to need, or may be combined as appropriate.

The absorbent article of the present embodiment is a sanitary article that is tried on by a wearer and absorbs liquids such as urine and menstrual blood. The absorbent article may be, for example, a band-type/underpant type paper diaper (so-called "disposable diaper"), a diaper pad, a sanitary napkin, a panty protector, and the like. In the following embodiments, the absorbent article is exemplified as a tape diaper.

In this embodiment, the related paper diaper sets the connection direction of the front body located on the abdomen of the wearer and the back body located on the back to the long-side direction, and the side facing the wearer's skin (inside of the try-on state) is the close-fitting side. The reverse side (outside of the try-on state) of the close-fitting side is set to the non-close-fitting side. In addition, let the connection direction of the body side and the non-body side be the thickness direction, and let the direction orthogonal to the longitudinal direction and the thickness direction be the width direction.

In addition, in this embodiment, unless otherwise stated, the description of "numerical value X to numerical value Y" refers to "numerical value X or more and numerical value Y or less".

[I. One embodiment] [1. Paper diapers]

First, referring to FIG. 1, the basic configuration of a paper diaper will be described. Here, the configuration of the crotch portion 1 located under the crotch of the wearer in the paper diaper will be mainly described.

The lower crotch 1 of the paper diaper is located at the center in the longitudinal direction. The crotch portion 1 is provided with an absorber 10 on the inner side in the width direction, and a side sheet (sheet) 20 is provided on the body side on the outer side in the width direction.

The absorber 10 is a liquid-absorbent element composed of a plurality of sheet-like or pad-like members. In this absorbent body 10, a top sheet (also called "sandwich sheet") 13 is arranged on the body side of the absorbent pad (also called "core") 12 covered (wrapped) by the wrapping sheet 11, and a back is arranged on the non-body side Sheet 14. In addition, the non-fitting side of the absorber 10 (that is, the non-fitting side of the back sheet 14) is covered with a cover sheet 15.

The absorber 10 allows the liquid excreted by the wearer to be absorbed by the absorbent pad 12 so that the wrapping sheet 11 and the top sheet 13 have the property of penetrating the liquid (liquid penetrability). On the other hand, in order to prevent the liquid absorbed through the absorbent pad 12 from leaking, the back sheet 14 and the cover sheet 15 have the property that the liquid cannot penetrate (liquid permeability).

In addition, in order to improve the applicability of the paper diaper to the wearer, the liquid diffusibility discharged to the absorber 10, the air permeability of the paper diaper, and the like, the groove-shaped pattern 2 is provided in the absorber 10.

The side sheet 20 is a sheet-like member provided to prevent liquid leakage of the paper diaper. Therefore, the side panel 20 also has liquid impermeability. This side panel 20 has the predetermined water resistance described in detail later.

Here, in the side panel 20, pleats 21 and 22 are provided along the longitudinal direction at each end portion in the width direction and its peripheral edge portion (hereinafter referred to as "end edge portion"). In the side panel 20, the three-dimensional gathers 21 standing upright on the body side are formed on the inner edge in the width direction, and the leg gathers 22 projecting outward on the width direction are formed on the outer edge in the width direction.

The three-dimensional pleats 21 are provided to prevent the discharged liquid from leaking outward in the width direction.

In the three-dimensional pleats 21, the side sheets 20 have sheet portions 20a, 20b at the inner edges in the width direction that are bent and overlapped, and the first yarns extending in the longitudinal direction are surrounded by these sheet portions 20a, 20b Rubber (elastic member) 31. In other words, the side sheet 20 is arranged with the inner wall sheet portion 20 a on the inner side in the width direction with respect to the first thread rubber 31, and the outer wall sheet portion 20 b on the outer side with respect to the first thread rubber 31 in the width direction. Therefore, part of the side panel 20 is overlapped by the two sheet sections 20a and 20b.

According to this, the first silk rubber 31 is built in the place where the sheet portions 20 a and 20 b of the side sheet 20 are folded and overlapped, thereby forming a three-dimensional crumpled 21 standing upright on the side of the body and subjected to a shrinking treatment.

The leg gathers 22 are provided to improve the traceability of the wearer's feet to improve comfort.

The leg gathers 22 overlap the outer sheet portion 20c of the lateral edge of the side sheet 20 and the outer sheet portion 15c of the lateral edge of the cover sheet 15 and use this The outer sheet portions 20c and 15c surround the second silk rubber (elastic member) 32 extending in the longitudinal direction.

According to this, the second silk rubber 32 is built in the overlapping portion of the side sheet 20 and the outer sheet portions 20c, 15c of the cover sheet 15 to form a crumpled leg fold that protrudes outward in the width direction twenty two.

[2. Side panels]

Next, the detailed structure of the side panel 20 will be described.

This side panel 20 is composed only of a spun bonded nonwoven fabric using thermoplastic resin fibers. Therefore, for example, a non-woven fabric containing a melt-blown layer (melt-blown non-woven fabric) such as an SMS non-woven fabric or a SMMS non-woven fabric, or a melt-blown non-woven fabric composed only of a melt-blown layer is not included in the side panel 20.

The so-called "spun-bonded nonwoven fabric" is a sheet-like member obtained by spinning a continuous fiber from thermoplastic resin and then aggregating it. In this spun bonded nonwoven fabric, the accumulated spun yarns become longer fibers (long fibers), respectively. Here, by applying either or both of heat and/or pressure, the spun bonded nonwoven fabric is subjected to an embossing process in which fibers are welded to each other.

Here, the specific method of manufacturing the spunbonded nonwoven fabric can be exemplified as follows.

First, the long fiber group composed of the spinning spun out of the thermoplastic resin in a molten state is introduced into the pneumatic suction cup and extended to defibrate, and then the fiber web can be obtained by gathering on the conveyor belt. Next, the long fiber groups forming the fiber web are joined together by embossing. For example, irregular patterns arranged regularly in the flow direction of the conveyor belt and its orthogonal directions are provided with a web by an embossing roller having irregularities corresponding to the irregular patterns formed on the outer periphery. In this way, the embossed fiber web is made into spunbonded nonwoven fabric.

In addition, the "melt-blown nonwoven fabric" refers to a sheet-like member obtained by aggregating short fibers (short fibers) produced by blowing out molten thermoplastic resin in a spray state. The melt-blown non-woven fabric has a tendency to have lower strength and smaller openings than the spun bonded non-woven fabric.

Hereinafter, the side sheet 20 will be described in detail in the order of structural configuration and chemical configuration.

[2-1. Structural construction]

The side sheet 20 of this embodiment, as shown in FIG. 2, uses fibers with a smaller diameter than those used for conventional spunbonded nonwoven fabrics (see the element symbol 41 in FIG. 3 ), and is manufactured at high density. The spun-bonded non-woven fabric with smaller pores can suppress the decrease in strength and has a predetermined water resistance. That is, the water resistance of the side sheet 20 is responsible for the spunbonded nonwoven fabric constituting the side sheet 20. Therefore, the spunbonded nonwoven fabric has a predetermined water resistance.

The "predetermined water resistance" herein refers to the physical properties that continuously satisfy the water pressure resistance required for the side panel 20 when water pressure is repeatedly applied.

The spunbonded nonwoven fabric used for the side panel 20 can ensure the strength, so even if the water pressure is repeatedly applied, the water pressure resistance can be suppressed from decreasing or changing, and because the openings are smaller, the water pressure resistance is improved. In other words, the side panel 20 composed of spun bonded nonwoven fabric ensures stronger strength than that of, for example, a nonwoven fabric containing a meltblown layer, and is not easily damaged even when water pressure is applied, and it is easy to maintain the water pressure resistance corresponding to the "opening". Therefore, even if the water pressure is repeatedly applied, the water pressure resistance is not easily reduced.

The above-mentioned predetermined water resistance naturally refers to the "water pressure resistance" of the spunbonded nonwoven fabric, which corresponds to the "opening" and "the area ratio of the embossed portion of the spunbonded nonwoven fabric (hereinafter referred to as "embossed area ratio").

Here, the spunbonded nonwoven fabric used for the relevant side panel 20 will be described with respect to "water pressure resistance", "opening", and "embossed area ratio".

<Water pressure resistance>

The so-called "water pressure resistance" refers to the upper limit of water pressure that can be tolerated. Specifically, the upper limit of the water surface height relative to the spunbonded nonwoven fabric is "water pressure resistant" when the water contained in the bottomless cylinder provided on the spunbonded nonwoven fabric does not penetrate.

Specifically, when the water pressure resistance is repeatedly measured in accordance with ISO811, the decrease in the second water pressure resistance P ₂ measured after the second time relative to the first water pressure resistance P ₁ measured in the first time is below the predetermined pressure P _P The spun-bonded nonwoven fabric is used for the side panel 20.

In order to prevent leakage of the discharged liquid, the first water-resistant pressure P ₁ and the second predetermined pressure P ₂ from which the predetermined pressure P _P is subtracted from the first water-resistant pressure P ₁ must be higher than the necessary water pressure. The water pressure system is, for example, 130 mmH ₂ O.

Here, the first water pressure resistance P ₁ system is 160 mmH ₂ O or more. The first water pressure resistance P ₁ is preferably 170 mmH ₂ O or more, and more preferably 180 mmH ₂ O or more from the viewpoint of preventing liquid leakage.

Furthermore, the predetermined pressure P _P is set below 30 mmH ₂ O. The predetermined pressure P _P is preferably 20 mmH ₂ O or less, and more preferably 10 mmH ₂ O or less from the viewpoint of maintaining liquid leakage prevention performance.

Therefore, the second water pressure resistance P _{2 is} set to at least 130 (=160-30) mmH ₂ O or more, preferably 140 (=170-30=160-20) mmH ₂ O or more, more preferably 150 (=180- 30=170-20=160-10) mmH ₂ O or more. Furthermore, the second excellent water pressure resistance P ₂ is preferably 160 (=180-20=170-10) mmH ₂ O or more, and the best system is 170 (=180-10) mmH ₂ O or more.

<opening>

The so-called "opening" refers to the parameter of the size of pores (fine pores) in the spunbonded nonwoven fabric. Therefore, if the "opening" is small, the liquid will not penetrate easily; on the contrary, if the "opening" is large, the liquid will penetrate easily. In addition, the smaller the "opening", the higher the "water pressure resistance".

However, as the water pressure applied to the side panels 20 increases, the spunbonded nonwoven fabric will stretch and cause the "opening" to become larger, so strictly speaking, the size of the "opening" and the "water pressure resistance" are not linear (linear )correspond. In addition, the pore size of the spunbonded nonwoven fabric is not uniform but varies. Therefore, it is difficult to directly use the "opening" system as the corresponding parameter of "water pressure resistance".

Here, for the corresponding parameter of "aperture", "fineness" and "basic weight" that do not change regardless of the level of water pressure applied to the side panel 20 are used.

The so-called "fineness" refers to the corresponding parameters of the fiber diameter (thickness) and cross-sectional area of the fiber, expressed by the weight of each predetermined length. Here, the gram number [Danny] per 9000m of the relevant fiber is used as "fineness". Therefore, the smaller the "fineness" of the spunbonded nonwoven system, the finer the fiber diameter.

In addition, because the fiber diameter of the spunbonded non-woven fabric will vary, the average value of the "fineness" of the fiber is used as a parameter. Therefore, the average value of "fineness" of fibers is simply called "fineness".

The so-called "basic weight" is the corresponding parameter of the thickness of the nonwoven fabric or the degree of lamination, which is expressed in terms of weight per unit area. Here, the number of grams per square meter is referred to as "basic weight".

On the basis of the same "basic weight", the smaller the "fineness", the smaller the fiber diameter and the more the number of fibers (fiber count), so it can be said that the "opening" is smaller. In addition, under the same "fineness" basis, the larger the "basic weight", the more the number of fibers increases, so it can be said that the "opening" is smaller.

The side sheet 20 of this embodiment uses a spun-bonded nonwoven fabric having a "fineness" of 0.1 to 1.0 denier and a "basis weight" of 8 to 20 g/m ² .

If the "fineness" is less than 0.1 denier, the strength of the fiber decreases and the fiber diameter is smaller, so the spinnability of the fiber decreases. On the other hand, if the "fineness" is greater than 1.0 Danny, the "opening" tends to become larger because the fiber diameter is larger. The "fineness" is preferably 0.2 to 0.8 Danny and more preferably 0.4 to 0.6 Danny from the viewpoint of ensuring the spinnability of the fiber and suppressing "opening".

If the "weight basis" is less than 8g / m ^2, since the thickness and strength decreases, thus reducing the possibility of adhesion will spin forming nonwoven fabric. On the other hand, if the "basic weight" is greater than 20 g/m ² , the thickness and strength of the fabric may increase, so that the sense of touch (skin touch) of the spun-bonded nonwoven fabric may decrease. The "basis weight" is preferably from 10 to 18 g/m ² and more preferably from 12 to 16 g/m ² from the viewpoint of taking into consideration the formability and touch of the spun bonded nonwoven fabric.

By setting the "fineness" and "basic weight" within the above-mentioned predetermined range, the spun bonded nonwoven side panel 20 can suppress the decrease in strength, and the fibers that are thinner than those of the conventional spun bonded nonwoven fabric are designed with high density , You can shrink the "opening". Therefore, the spunbonded nonwoven fabric used for the side panel 20 can ensure a predetermined water resistance.

<embossed area ratio>

The so-called "embossed area ratio" is the ratio of the total planar area of the embossed portion to the total planar area of the spunbonded nonwoven fabric. Here, when the total planar area of the spun bonded nonwoven fabric is set to "S1" and the total planar area of the embossed portion is set to "S2", the percentage of "S1" relative to "S2" (=<S1/S2 >×100) Set to "embossed area ratio".

The side panel 20 of the present embodiment uses a spunbonded nonwoven fabric having an "embossed area ratio" of 5 to 25%.

If the "embossed area ratio" is less than 5%, the spunbonded non-woven fabric is likely to fluff, and the shape of the side panel 20 may be reduced. On the other hand, if the "embossed area ratio" is greater than 25%, the strength or rigidity of the side panel 20 will increase, and there is a possibility that the tactile sensation will decrease. The "embossed area ratio" is preferably from 6 to 20% from the viewpoint of taking into account the shapeability and touch of the side panel 20. In addition, the larger the "embossed area ratio", the higher the water pressure resistance of the spunbonded nonwoven fabric.

<other>

In the side sheet 20 of the present embodiment, a spunbonded nonwoven fabric in which fibers are aligned in a specific direction may be used, or a spunbonded nonwoven fabric in which fibers are irregularly aligned may be used.

When the former is spun and bonded to non-woven fabric, the strength and rigidity (with anisotropy) can be ensured in a specific direction, so the design freedom of absorbent articles can be improved. If the latter is used for spun bonded nonwoven fabrics, since the variation in strength and rigidity (isotropy) can be suppressed, the side panel 20 can be arranged without considering the alignment, which contributes to the manufacturing workability of absorbent articles. Promote.

[2-2. Chemical composition]

Next, the chemical structure of the spun bonded nonwoven fabric side sheet 20 will be described. The chemical structure described hereinafter is an example of ensuring fiber spinnability while suppressing the fiber diameter used for the spun bonded nonwoven fabric forming the side sheet 20.

The fiber of the spunbonded nonwoven fabric forming the side panel 20 uses polyolefin resin. The polyolefin resin contains polypropylene (PP). In addition, the so-called "polyolefin resin" may also cover polyethylene (PE).

The above-mentioned polypropylene can be roughly classified into low-crystalline polypropylene (low-crystalline polyolefin resin) with a melting point of less than 100°C and high-crystalline polypropylene (high-crystalline polyolefin resin) with a melting point of 100°C or higher. Examples of the highly crystalline polypropylene system include propylene homopolymer, propylene random copolymer, and propylene block copolymer. In addition, the related low crystallinity polypropylene will be described in detail in the following item [2-2-2].

[2-2-1. Polyolefin resin]

The melt flow rate (also referred to as "MFR") of the polyolefin resin is preferably 20 to 100 g/10 minutes. In addition, the "melt flow rate" refers to one of the scales of the fluidity of a resin in a solution state. The larger the value, the better the fluidity and formability, but there is a tendency for the tensile strength to decrease.

If the melt flow rate is less than 20 g/10 minutes, there is a possibility that the spinnability of the fiber formed from the polyolefin resin will decrease. On the other hand, if the melt flow rate is greater than 100 g/10 minutes, the side sheet 20 composed of the spun bonded nonwoven fabric formed of the polyolefin resin may have a reduced tactile feel. Therefore, the melt flow rate of the polyolefin resin is more preferably from 20 to 90 g/10 minutes and from 20 to 80 g/10 minutes from the viewpoint of ensuring spinnability and touch.

In addition, other thermoplastic resins and additives may be mixed into the polyolefin resin used.

The other thermoplastic resin may contain an olefin polymer. Examples of the olefin-based polymerization system include propylene-ethylene copolymer, propylene-ethylene-diene copolymer, ethylene/α-olefin copolymer, ethylene-vinyl acetate copolymer, and hydrogenated styrene elastomer. These systems can be used alone or in combination of two or more.

Additives include, for example, lubricants, foaming agents, crystal nucleating agents, weather-resistant stabilizers, ultraviolet absorbers, light stabilizers, heat-resistant stabilizers, antistatic agents, release agents, flame retardants, synthetic oils, waxes, Electrical property modifiers, anti-slip agents, anti-caking agents, viscosity modifiers, anti-coloring agents, anti-fogging agents, pigments, dyes, plasticizers, softeners, aging inhibitors, hydrochloric acid absorbents, chlorine capture agents, antioxidants , Anti-sticking agents and other conventional and well-known things.

[2-2-2. Low crystallinity polypropylene]

Next, the chemical structure of the low-crystalline polypropylene used will be described in detail.

First, the basic three-dimensional rules (sequences) of the low-crystalline polypropylene used will be described. Here, the stereotaxic rule of the two-unit methyl group in which two side chain methyl groups are oriented in the same direction is referred to as "meso<m>", and the two-unit methyl group is stereoscopically oriented in a two-unit group in different directions. The rule is called "racemic <r>". In addition, the three-dimensional rule arranged by two two-unit groups is called "triple unit sequence", and the three-dimensional rule arranged by three two-unit groups is called "five unit sequence".

The triad sequence system can be exemplified by: meso triad <mm>, racemic triad <rr>, triad <mr>. The meso three-unit system is composed of two meso-arranged three-dimensional rules, and the meso three-unit system is composed of two meso-arranged three-dimensional rules. The three-unit system is in the order of meso and race Three-dimensional rules of arrangement.

The quintuple sequence system can be exemplified by: meso pentads <mmmm>, racemic pentads <rrrr>, racemic meso rac meso meso pentads <rmrm>. The meso-five unit group is composed of three meso-arranged three-dimensional rules, and the meso-five unit unit is composed of three meso-arranged three-dimensional rules. The three-dimensional rules of the system are arranged in the order of racemization, racemization, racemization, and racemization.

In addition, the proportion of the above-mentioned various stereoscopic rules in the low-crystalline polypropylene used (here, set as a percentage) is defined by the name {"stereoscopic rule name" + "fraction"} [mol %]. For example: in the low crystalline polypropylene used, the ratio of meso-five units is the meso-five component rate, and the ratio of racemic meso-racemic and meso-five is the racemic The meso-meso-meso five-component composition rate.

The low-crystalline polypropylene used may be, for example, a crystalline polypropylene in which the stereoregularity slightly collapses. Specifically, it is preferable to use low-crystalline polypropylene that satisfies the following <characteristic a> to <characteristic h>.

<characteristic a> meso-component ratio of five units

The component ratio of meso-five units is preferably 30-80 mol%.

If the component ratio of meso-five units is less than 30 mol%, there is a possibility that the low-crystalline polypropylene will cure slowly after melting and the fiber formability will decrease. On the other hand, if the meso five-unit composition ratio is greater than 80 mole %, there is a possibility that the crystallinity of the low crystallinity polypropylene is too high, which may cause the fiber to easily break and the fiber formability to decrease. Therefore, from the viewpoint of ensuring the fiber formability, the meso five-unit component rate is preferably 40 to 70 mol%, and more preferably 50 to 60 mol%.

<Characteristic b> Ratio of meso-five-component ratio and racem-five-component ratio

When the meso-five component rate is set to "A" and the meso-five component rate is set to "B", it is best to satisfy the inequality I "B/(1-A)≦0.1".

The left side of inequality I can be set as an index indicating the regularity distribution uniformity of low crystalline polypropylene. The larger the value, the more likely it is the cause of sticking. Therefore, from the viewpoint of indeed suppressing sticking, the better system satisfies the inequality I'"B/(1-A)≦0.05", and the particularly good system satisfies the inequality I" "B/(1-A)≦0.04".

<Characteristic c> Racemic racemic racemic racemic meso five-unit composition rate

The five-unit composition ratio of racemic meso-racemic meso-meso is preferably greater than 2.5 mole %.

If the five-component ratio of racemic meso-racemic meso-meso is less than 2.5 mol%, the randomness of low-crystalline polypropylene is reduced, which is caused by the crystallization of the same row of polypropylene block chains. The crystallinity is improved. Therefore, there is a possibility that the fiber is easily broken and the fiber formability is lowered. Therefore, from the viewpoint of ensuring fiber formability, the component ratio of the racemic meso-racemic meso-five unit is preferably greater than 2.6 mol%, and more preferably greater than 2.7 mol%.

In addition, the upper limit of the component rate of the five units of racemic racemic racemic racemic meso is generally about 10 mole %. Therefore, the five-component composition ratio of racemic meso-racemic meso-meso is preferably 10 mol% or less.

<Characteristic d> The ratio of meso-three-component ratio, racemic three-component ratio and the ratio of three-component ratio

When the meso three-unit component rate is set to "C", the racemic three-unit component rate is set to "D", and the three-unit component rate is set to "E", it is preferable to satisfy the inequality II "C× D/E ² ≦2.0”.

The left side of the inequality II can be set as an index indicating the randomness of the polymer, and the smaller the value, the tendency for the randomness to increase. Therefore, the higher the randomness of the polymer, the less likely the fiber is to break and the more likely it is to suppress sticking, so it is possible to ensure fiber formability while suppressing excessive increase in randomness, and it is better to suppress sticking. The system satisfies the inequality II'"0.2≦C×D/E ² ≦2.0”, and the super good system satisfies the inequality II” “0.25≦C×D/E ² ≦1.8”.

<Characteristic e> Weight average molecular weight

The low-crystalline polypropylene used preferably has a weight average molecular weight of 10,000 to 200,000.

If the weight-average molecular weight is less than 10,000, the viscosity of the low-crystalline polypropylene may be too low, which may cause the fiber to break easily and the fiber formability may decrease. On the other hand, if the weight-average molecular weight is greater than 200,000, the viscosity of the low-crystalline polypropylene may be too high, which may reduce the fiber spinnability. Therefore, the weight average molecular weight is more preferably from 30,000 to 100,000, and from 40,000 to 80,000 from the viewpoint of taking into account the fiber formability and spinnability.

<Characteristic f> Molecular weight distribution (ratio of weight average molecular weight and number average molecular weight)

Regarding the low crystalline polypropylene used, when the weight average molecular weight is "Mw" and the number average molecular weight is "Mn", it is preferable to satisfy the inequality III "Mw/Mn≦4".

The left side of inequality III can be set as an indicator of fiber sticking. If it is greater than 4, the fiber sticks easily. Therefore, from the viewpoint of suppressing sticking, the better system satisfies the inequality III' "Mw/Mn≤3", and the particularly good system satisfies the inequality III" "Mw/Mn≤2".

<Characteristic g> Amount of extract of boiling diethyl ether

Regarding the low-crystalline polypropylene used, it is preferred that the amount of boiling diethyl ether extract is 0 to 10% by mass.

The amount of boiling diethyl ether extract can be set as an indicator of fiber sticking. The larger the value, the easier the sticking. Therefore, the amount of boiling diethyl ether extract is preferably from 0 to 5% by mass from the viewpoint of suppressing fiber sticking.

<Characteristic h> Mass ratio of low crystalline polypropylene

The mass ratio of the low crystalline polypropylene used is preferably 5 to 50% by mass based on the total solid content. The "total solid content" herein refers to the total amount of low-crystalline polypropylene and high-crystalline polypropylene.

If the above mass ratio is less than 5 mass%, the shortcomings of highly crystalline polypropylene cannot be compensated for, the number of triggers will not be increased, and the fiber diameter will not be easily reduced. On the other hand, if the mass ratio is within the above-mentioned mass% range, since it does contain low-crystalline polypropylene, the fiber is not easily broken, and the spinnability is improved, so that the fiber with a smaller diameter can be stably produced. From this point of view, the mass ratio of the low-crystalline polypropylene is more preferably 10 to 50% by mass, and particularly preferably 20 to 50% by mass.

<Other> manufacturing method

The method for producing the low-crystalline polypropylene satisfying the above <characteristic a> to <characteristic h> can be a method using a metallocene catalyst, and the production method described in Japanese Patent No. 4242498.

[3. Function and effect]

Since the paper diaper is constructed as described above, the following actions and effects can be obtained.

(1) According to the paper diaper of this embodiment, the spunbonded non-woven fabric that becomes the side sheet 20 has a predetermined water resistance, and therefore, it is possible to suppress excretion liquid from penetrating through the side sheet 20 and to prevent liquid leakage. Therefore, the comfort of the wearer can be ensured.

After all, conventional paper diapers do not have the idea of making spunbonded nonwovens water-resistant.

The reason may be, for example, that it is difficult to balance water resistance and touch. For example, if the basis weight of the spunbonded nonwoven fabric is large, although the water resistance can be ensured, the feeling of touch is easily reduced. Conversely, if the basis weight of the spun-bonded nonwoven fabric is suppressed to ensure touch, it is difficult to ensure water resistance.

Therefore, for sanitary products or absorbent articles, such as paper diapers, which are premised on ensuring touch, there is a background factor that makes it difficult to produce water-resistant spunbonded nonwoven fabrics.

On the other hand, the paper diaper of this embodiment is proposed based on a new concept of making spun-bonded nonwoven fabrics have a predetermined water resistance. In other words, by making the spun-bonded nonwoven fabric used for the side panel 20 have a novel structure with a predetermined water resistance, while suppressing liquid leakage, it is possible to provide a paper diaper that ensures wearer comfort.

(2) It is known that the side panels of SMS nonwoven fabrics are used in paper diapers. If water pressure is applied, although the spunbonded nonwoven fabric layer will not be damaged, there is a possibility that the meltblown nonwoven fabric layer will be damaged. Therefore, the water pressure resistance of the damaged SMS nonwoven fabric is much lower than the water pressure resistance of the opening of the spun bonded nonwoven fabric layer under the SMS nonwoven fabric before the damage. Therefore, it is known to use SMS non-woven side panels, the water pressure resistance is likely to decrease when water pressure is repeatedly applied, and the reduced water pressure resistance may not meet the required water pressure resistance.

In contrast, the side sheet 20 of the present embodiment uses a spunbonded nonwoven fabric that can suppress the decrease or fluctuation of the water pressure resistance even if water pressure is repeatedly applied. Therefore, when the wearer excretes fluid intermittently (that is, even in the case where water pressure is repeatedly applied to the side panel 20), the liquid leakage can be continuously suppressed.

Specifically, the first water pressure resistance P _{1 is} set to 160 mmH ₂ O or more, and the predetermined pressure P _P reduced from the first water pressure resistance P ₁ to the second water pressure resistance P ₂ is set to 30 mmH ₂ O or less. That is, the second water pressure resistance P _{2 is} at least 130 (=160-30) mmH ₂ O or more. Accordingly, the water resistance pressures P ₁ and P ₂ are higher than the necessary water pressure to prevent leakage of the discharged liquid. Therefore, it is possible to surely continue to suppress leakage. In other words, the predetermined pressure P _P can be suppressed, and the leakage prevention function can be suppressed from decreasing.

(3) Furthermore, it is known that the side panels of SMS non-woven fabrics are used in conventional paper diapers. Melt-blown non-woven fabrics are used to ensure water resistance and touch, and spun bonded non-woven fabrics are used to ensure strength. Therefore, water resistance and tactile feel are not guaranteed by spun bonded nonwoven fabrics, but by meltblown nonwoven fabrics.

In contrast, the side panel 20 uses fibers with a smaller diameter than those used in conventional spunbonded nonwoven fabrics at high density. Specifically, a spun-bonded nonwoven fabric with a "fineness" of 0.1 to 1.0 Danny and a "basis weight" of 8 to 20 g/m ² is used for the side sheet 20. Therefore, the side panel 20 not only has a predetermined water resistance, but also can ensure a tactile feel.

(4) Furthermore, part of the side panel 20 overlaps the two sheet sections 20a and 20b. Therefore, the water pressure resistance of the side panel 20 can be increased where the two sheet material portions 20a and 20b overlap.

Therefore, the two sheet portions 20a and 20b are only bent and overlapped, and are not integrated in the overlapping direction. Therefore, compared with the side panels under twice the "basic weight", it is possible to suppress the decrease in the tactile sensation due to the increased rigidity. In short, the sheet parts 20a and 20b can be suppressed from being stiff (rough and hard).

(5) As mentioned above, the side panel 20 not only has a predetermined water resistance, but also ensures a tactile feel. Therefore, the side panel 20 can be arranged on the close-to-body side of the paper diaper that requires a tactile feel. Conversely, the spunbonded non-woven fabric side sheet 20 is disposed in the paper diaper on the side of the body to prevent liquid leakage and ensure a tactile feel.

(6) Similarly, since the side panel 20 has a predetermined water resistance, it can also ensure a tactile sensation. Therefore, the three-dimensional pleats 21 that particularly require a tactile sensation in paper diapers can use the side panel 20. Conversely, in a paper diaper in which the three-dimensional pleats 21 use the side panels 20, in addition to suppressing the occurrence of liquid leakage in the width direction, it can also ensure a tactile feel. Therefore, the comfort of the wearer can be ensured.

[II. Example]

Hereinafter, an embodiment of this case will be described.

In addition, the materials, usage amounts, ratios, processing contents, processing order, etc. shown in the following examples can be changed as appropriate before mentioning the purpose of this case. Therefore, the scope of this case should not be limited by the specific examples shown below.

[1. Manufacturing method of non-woven fabric]

First, referring to Table 1 above, the resin used for the nonwoven fabric material will be described.

For the resin A, a polypropylene-based polyolefin resin (highly crystalline polypropylene) is used. This resin A has a melting point of 162°C and a melt flow rate of 30 g/10 minutes.

In addition, as the resin B system, a polypropylene-based polyolefin resin (low crystallinity polypropylene) satisfying the above <characteristic a> to <characteristic h> is used. This resin B has a melting point of 52°C and a melt flow rate of 45 g/10 minutes.

A mixture in which the resin A and the resin B were mixed in the proportions shown in Table 1 was prepared. That is, a polypropylene fiber is spun to produce a non-woven fabric.

Hereinafter, a method of manufacturing the spunbonded nonwoven fabric (Examples 1 to 6 and Comparative Examples 4 to 6) will be described.

First, resin A and resin B are melted by an extruder to obtain a melt. Next, the melt was discharged from the spinning nozzle, and the polypropylene fiber was spun. Then, the spun polypropylene fiber is cooled with cooling air, and tension is applied with stretching air to become a predetermined fineness (fineness shown in Table 1), which is directly collected on the conveyor belt and becomes a predetermined basis weight (table 1 shows the basis weight) accumulated. Then, heat and pressure are applied to the accumulated polypropylene fibers by an embossing roller, and a part of them is melted at a predetermined embossed area ratio (embossed area ratio shown in Table 1), and the fibers are interwoven. Accordingly, the nonwoven fabrics of Examples 1 to 6 and Comparative Examples 4 to 6 were obtained.

Next, a method of manufacturing the SMS nonwoven fabric (Comparative Examples 1 to 3) will be described.

In this method, polypropylene fibers that become spunbonded nonwovens are accumulated, meltblown nonwovens are accumulated, and then polypropylene fibers that are spunbonded nonwovens are accumulated again. In addition, the formation and accumulation of the polypropylene fiber that becomes the spunbonded nonwoven fabric is the same as the above-mentioned production method.

Specifically, a melt-blown nonwoven fabric having a predetermined basis weight (basis weight shown in Table 1) was formed by a melt-blown method on a fiber web in which polypropylene fibers to be spun-bonded nonwoven fabric were accumulated. On top of it, it again accumulates into polypropylene fibers of spunbonded nonwoven fabric. Then, in the same manner as the method for producing a spunbonded nonwoven fabric, heat and pressure are applied using an embossing roll, and a part of it is melted at a predetermined embossing area ratio (embossing area ratio shown in Table 1) to interweave the fibers. In this way, the nonwoven fabrics of Comparative Examples 1 to 3 were obtained.

[2. Measurement methods and evaluation methods]

The measurement method or evaluation method for deriving the results shown in Table 1 above is shown in the following <Method i> to <Method vi>. In addition, the methods for evaluating the chemical composition are also shown in <Method vii>~<Method x>.

<Method i> Melt flow rate

The melt flow rate is based on Table 1 of JIS-K7210 "Test Methods for Melt Mass Flow Rate (MFR) and Melt Volume Flow Rate (MVR) of Plastics-Thermoplastic Plastics" using a melt index tester (manufactured by Toyo Seiki Co., Ltd.) : MELTINDEXERS-101) Melt flow device, measured according to spinneret aperture 2.095mm, spinneret hole length 0.8mm, load 2160g. The measurement was performed at a measurement temperature of 230°C, and the amount (g) of molten polymer discharge per 10 minutes was calculated from the time required to discharge a certain volume portion.

<Method ii> Fineness

For the fineness system, 10 cm at both ends of the manufactured nonwoven fabric was removed, approximately five equal portions in the width direction were taken, and a 1 cm square test piece was sampled, and the fiber diameters at each of 20 locations were measured with a microscope, and then calculated from the average value.

<Method iii> Basis weight

The basis weight is obtained by removing 10 cm from both ends of the manufactured nonwoven fabric, arbitrarily taking five test pieces of 20 cm long x 20 cm wide, measuring the mass, and converting the average value to the weight per unit area.

<Method iv> Embossed area ratio

The area ratio of embossing is to remove 10cm at both ends of the manufactured nonwoven fabric, roughly five equal parts in the width direction and sample 1cm square test piece, use a microscope to take an enlarged image of the nonwoven fabric, and then use an image processing program to determine the corresponding embossing. The area ratio of the recesses of the nonwoven fabric was 20 points each, and the average value was calculated.

<Method v> Water pressure resistance

The water pressure resistance is measured according to ISO811 or JIS L1092.

The measurement of water pressure resistance will be described in detail below.

When measuring the water pressure resistance, the prepared nonwoven fabric was cut into eight pieces of 20 cm square, and the cut nonwoven fabric was mounted on a sample support frame for FX-3000 water pressure tester manufactured by TEXTEST. The attached nonwoven fabric is one or two pieces, without wrinkles, and the measurement area is set to 100 cm ² .

Then, in the pressure test mode, the water pressure was increased at a rate of 600 mmH ₂ O/min and the water pressure resistance was measured. In this measurement, the pressure at three or more places where the water leaks is set as the water-resistant pressure.

When repeatedly measuring the water pressure resistance, remove the sample subjected to the water pressure resistance measurement from the above tester, and while attached to the sample holder, wipe the water from both sides (front and back) of the nonwoven sheet with paper towels, etc. The non-woven fabric was mounted on the tester again, and the water pressure resistance was measured in the same order.

<Method vi> Touch

The tactile sensation system removes 10 cm at both ends of the manufactured nonwoven fabric, arbitrarily takes five 20 cm long x 20 cm wide test pieces, sets it as a sample for measurement, and evaluates the feel (touch) when the subject touches it by hand. This evaluation is based on three levels of "○" (good), "△" (normal), and "×" (poor).

<Method vii> Molecular weight distribution

The equipment and conditions for measuring the relative molecular weight distribution are as follows:

GPC measuring device

Column: TOSO GMHHR-H(S)HT

Detector: RI detector WATERS150C for liquid chromatography

Measurement conditions

Solvent: 1,2,4-trichlorobenzene

Measuring temperature: 145℃

Flow rate: 1.0ml/min

Sample concentration: 2.2mg/ml

Injection volume: 160μl

Calibration line: Universal

Calibration

Analysis program: HT-GPC (Ver.1.0)

<Method viii> Boiling diethyl ether extraction

The equipment and conditions for the determination of the relative boiling diethyl ether extraction are as follows:

Soxhlet extractor

Measurement conditions

Extraction sample: 5~6g

Sample shape: powder (used after pulverizing the granulated material by crushing)

Extraction solvent: diethyl ether

Extraction time: 10 hours

Extraction times: more than 180 times

Calculation method of extraction amount: calculated by the following formula.

[Amount extracted from diethyl ether (g)/Packing powder weight (g)]×100

<Method ix> The meso-five component rate, the meso-five component rate, and the meso-meso-racemic meso-five component rate

The three-dimensional regular ratio of low-crystalline polypropylene used in spunbonded nonwoven fabrics was determined by measuring 13C-NMR mass spectrum. This measurement is performed in accordance with the assignment of peaks proposed by A. Zambelli et al. in "Macromolecules, 8, 687 (1975)".

The following lists the devices and conditions related to this measurement: Device: JNM-EX400 13C-NMR device manufactured by JEOL Ltd.

Method: Proton-to-hydrogen decoupling method

Concentration: 220mg/ml

Solvent: 90:10 mixed solvent of 1,2,4-trichlorobenzene and heavy benzene

Temperature: 130℃

Pulse width: 45°

Pulse repetition time: 4 seconds

Points: 10000 times

<calculation formula>

M=m/S×100

R=Y/S×100

S=P _ββ +P _αβ +P _αY

S: Signal strength of the side chain methyl carbon atom of the total propylene unit

P _ββ : 19.8~22.5ppm

P _αβ : 18.0~17.5ppm

P _αY : 17.5~17.1ppm

Y: Racemic five-unit chain: 20.7~20.3ppm

m: meso-five unit chain: 21.7~22.5ppm

<Method x> Melting point and crystallization temperature

The melting point and crystallization temperature are obtained according to the following equipment and methods.

Using a differential scanning calorimeter (manufactured by PerkinElmer, DSC-7), 10 mg of the sample was melted in a nitrogen environment at 230°C for 3 minutes, and then cooled to 0°C at 10°C/min. At this time, the maximum peak of the crystallization exotherm curve obtained is set as the crystallization temperature. Furthermore, after further maintaining at 0°C for 3 minutes, the maximum peak of the melting endotherm curve obtained by raising the temperature at 10°C/min was taken as the melting point.

[3. Investigation]

Next, the nonwoven fabrics of Examples 1 to 6 and Comparative Examples 1 to 6 will be examined.

<Example>

First, the spunbonded nonwoven fabrics of Examples 1 to 6 are examined.

The spunbonded non-woven fabrics of Examples 1 to 6, the water pressure resistance measured in the first time (first water pressure resistance P ₁ ) and the water pressure resistance measured in the second time (second water pressure resistance P ₂ ) were above 130 mmH ₂ O, It is higher than the necessary water pressure to prevent the leakage of discharged liquid. Furthermore, the amount of decrease (predetermined pressure P _P ) from the first measurement of the water pressure resistance to the second measurement of the water pressure resistance (second water pressure resistance P ₂ ) is suppressed to 30 mmH ₂ O or less.

According to this, the reason why the liquid leakage function can be reliably prevented, and the reduction of this function is suppressed. For the examples 1 to 5 based on the above-mentioned "fineness" and "basic weight", high-density use of small-diameter fibers can be considered as spun-bonded The non-woven fabric suppresses the decrease in strength and has a predetermined water resistance.

If the water pressure resistance measured in the first and second times is observed in detail, Examples 3 and 4 are 160-170mmH ₂ O, Examples 1, 2 and 6 are 170-180mmH ₂ O or more, and Example 5 is 200mmH ₂ O or more.

The reason why the water pressure resistance measured in Example 5 is higher than that in Examples 1 to 4 and 6. It can be considered that Examples 1 to 4 and 6 use one piece of spunbonded nonwoven fabric, while Example 5 uses two pieces of spunbonded It is used only after the non-woven fabric overlaps.

Furthermore, if we focus on the decrease in the water pressure resistance from the first measurement to the second measurement of the water pressure resistance (predetermined pressure P _P ), all of Examples 1 to 6 are below 10 mmH ₂ O, especially Examples 1 and 6 are 0 mmH ₂ O.

Accordingly, the reason why the water pressure resistance can be maintained in Examples 1 and 6 is considered to be because the embossed area ratio is higher than that in other Examples 2 to 5. In addition, for Example 6, it can be considered that the basis weight is larger than that of the other Examples 1 to 5.

In addition, the spunbonded nonwoven fabrics of Examples 1 to 5 were also evaluated as "○" in terms of touch.

Based on the reason why the tactile evaluation is good, it is considered that the spunbonded nonwoven fabric is due to the high-density use of small-diameter fibers as described above.

In addition, although the spunbonded nonwoven fabric of Example 6 had a water pressure resistance of 130 mmH ₂ O or more measured in the first time and the second time, the tactile evaluation was “×”.

Based on the reason that the tactile evaluation is low, it can be considered that because the "fineness" and "basic weight" are larger than the spunbonded nonwoven fabrics of Examples 1 to 5, the thick fibers are stacked thickly, which results in the rigidity of the nonwoven fabric. Increased, due to stiffness.

<Comparative example>

Next, the nonwoven fabrics of Comparative Examples 1 to 6 are examined.

Although the SMS nonwoven fabrics of Comparative Examples 1 to 3 had a water pressure resistance of 160 mmH ₂ O or more in the first measurement, the water pressure resistance measured in the second time was less than 130 mmH ₂ O. That is, for the SMS nonwoven fabrics of Comparative Examples 1 to 3, the decrease in the water pressure resistance measured from the first time to the second time measured water pressure resistance decreased by more than 30 mmH ₂ O. In addition, the water pressure resistance measured in the second time is lower than the necessary water pressure to prevent leakage of the discharged liquid.

Accordingly, the reason why the decrease in the water pressure resistance cannot be suppressed, and the reason why the water pressure resistance measured for the second time is low is considered as the following reason.

In the SMS nonwoven fabrics of Comparative Examples 1 to 3, the "basis weight" of the spunbonded nonwoven fabric layer was smaller than that of the spunbonded nonwoven fabrics of Examples 1 to 6. In addition, in the SMS nonwoven fabrics of Comparative Examples 1 to 3, the "fineness" of the nonwoven fabric layer is larger than that of the spun bonded nonwoven fabrics of Examples 1 to 5, so the "opening" is larger. On the other hand, in the SMS nonwoven fabrics of Comparative Examples 1 to 3, although the "opening" of the meltblown nonwoven fabric layer is smaller than the spunbonded nonwoven fabrics of Examples 1 to 6, the strength is lower.

Therefore, it can be considered that the SMS nonwoven fabrics of Comparative Examples 1 to 3 were damaged during the first water pressure resistance measurement, and the "opening" (fineness and basis weight) of the spunbonded nonwoven fabric was provided around the damaged area. The corresponding water pressure resistance is determined by the second measurement.

In addition, the SMS nonwoven fabrics of Comparative Examples 1 to 3 had a tactile evaluation system "△".

Accordingly, the reason why the tactile evaluation is not good is because the spun-bonded non-woven fabric layer in the SMS non-woven fabric has a large "fineness", and therefore has high rigidity and stiffness.

For the spunbonded nonwoven fabrics of Comparative Examples 4 to 6, the water pressure resistance measured for the first time was 160 mmH ₂ O or less, and the target water pressure resistance could not be obtained. Therefore, the second water pressure resistance measurement was not performed.

The spin-bonded nonwoven fabric of the related comparative example 4 has a larger "opening" than the spin-bonded nonwoven fabrics of Examples 1 to 5 because of its larger "fineness", and the water pressure resistance measured for the first time is relatively low.

The spin-bonded nonwoven fabric of the related comparative example 5 has a smaller "basis weight" than that of the spin-bonded nonwoven fabrics of examples 1 to 6, so it can be considered that the "opening" is large and the water pressure resistance measured for the first time is relatively low.

In the spun bonded nonwoven fabric of the related comparative example 6, because the content of the resin B is large, it is considered that the fiber used is easily broken, and the water pressure resistance measured for the first time is low.

[III. Variations]

Finally, other modified examples of this embodiment will be described.

The side panel 20 is not limited to only being composed of spun bonded nonwoven fabric, but may also include meltblown nonwoven fabric. For example, SMS nonwoven fabric is used for the side panel 20. In this case, the above-mentioned spunbonded non-woven fabric layer with a predetermined water resistance is contained in the SMS non-woven fabric. Accordingly, if the meltblown nonwoven fabric is contained in the side panel 20, the predetermined water resistance can be ensured, and the first water pressure resistance P ₁ can be further improved, which helps to improve the comfort of the wearer.

In addition, the spunbonded nonwoven fabric having a predetermined water resistance is not limited to the side sheet 20, but can also be used for other sheets such as the back sheet 14 and the cover sheet 15. In other words, the above-mentioned spun bonded nonwoven fabric and the sheet using it are not limited to absorbent articles such as paper diapers, but can be applied to various articles requiring a predetermined water resistance. In any case, the use of the above-mentioned spunbonded non-woven fabric can continuously meet the required water pressure resistance. The sheet material using the spunbonded nonwoven fabric can also continuously meet the required water pressure resistance, and other functionalities can be added by using the constituent elements other than the spunbonded nonwoven fabric in the sheet material.

1‧‧‧ Lower crotch

2‧‧‧pattern

10‧‧‧absorber

11‧‧‧Wrapped tablets

12‧‧‧absorption pad

13‧‧‧Top slice

14‧‧‧Back sheet

15‧‧‧ Cover sheet

15c‧‧‧Outside Sheet Department

20‧‧‧Side (sheet)

20a‧‧‧Inner Wall Sheet Department

20b‧‧‧External wall sheet department

20c‧‧‧Outside Sheet Department

21‧‧‧ Three-dimensional broken pleats

22‧‧‧Legs

31‧‧‧The first silk rubber

32‧‧‧Second silk rubber

Claims (10)

An absorbent article having three-dimensional pleats erected on the side of the body, characterized in that the three-dimensional pleats are composed of sheets containing spun-bonded non-woven fabric and not containing melt-blown non-woven fabric; the spun-bonded non-woven fabric It consists of thermoplastic resin fibers; the above spunbonded nonwoven fabric has a decrease in the second water pressure measured after the second time relative to the first water pressure resistance measured after the second time when the water pressure resistance is repeatedly measured according to ISO811 , The predetermined water resistance below the predetermined pressure; the first water pressure resistance is above 160mmH ₂ O, the above predetermined pressure is below 30mmH ₂ O; the average value of the fineness of the fiber is 0.1~1.0 Danny; the base of the spun bonded nonwoven fabric The weight is 8~20g/m ² . The absorbent article according to claim 1, wherein the thermoplastic resin is a polyolefin resin containing polypropylene. The absorbent article according to claim 2, wherein the polyolefin resin is a low-crystalline polyolefin resin that satisfies the following items based on the total solid content of 5 to 50% by mass: meso five-unit component rate 30 to 80 mol %; when the above meso-five component rate is set to "A" and the meso-five component rate is set to "B", the inequality I "B/(1-A)≦ is satisfied 0.1"; racemic racemic racemic racemic meso five-unit component rate is greater than 2.5 mol%; set the meso three-unit component rate to "C", the racemic three-unit component rate is set When it is "D" and the three-unit component rate is set to "E", it satisfies the inequality II "C×D/E ² ≦2.0"; the weight average molecular weight is 10000~200000; the above weight average molecular weight is set to "Mw", When the number average molecular weight is set to "Mn", the inequality III "Mw/Mn≤4" is satisfied; the amount of extract using boiling diethyl ether is 0 to 10% by mass. The absorbent article according to any one of claims 1 to 3, wherein the area ratio of the embossed portion where the fibers of the sheet are fused to each other is 5 to 25%. The absorbent article according to any one of claims 1 to 3, wherein the above-mentioned sheet material overlaps two or more sheets. The absorbent article according to claim 4, wherein the above-mentioned sheets are overlapped by two or more sheets. The absorbent article according to any one of claims 1 to 3, wherein the above-mentioned sheet is disposed on the body side. The absorbent article according to claim 4, wherein the sheet is arranged on the side of the body. The absorbent article according to claim 5, wherein the sheet is arranged on the side of the body. The absorbent article according to claim 6, wherein the above-mentioned sheet is arranged on the side of the body.

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