RU2575448C1 - Non-woven fabric - Google Patents

Abstract

FIELD: textiles, paper.

SUBSTANCE: non-woven fabric (1) according to the present invention is a hydrophilic non-woven fabric, in which the fibrous structure (11) is present, where the long fibres (2) are bonded with the heat-adhesive device (3). The non-woven fabric (1) comprises fibres (20) obtained by breaking some of the long fibres (2), one end portions (20a) of which are bonded with the heat-adhesive device (3) and the other end portions of which are free end portions (20b) located separately and protruding from the fibrous structure (11). The degree of hydrophilicity of the fibres (20) having free end portions (20b) is lower than the degree of hydrophilicity of fibres constituting the fibrous structure (11).

EFFECT: increase in strength.

13 cl, 14 dwg, 1 tbl

Description

FIELD OF THE INVENTION

The present invention provides a non-woven fabric comprising long fibers.

BACKGROUND

For an absorbent article, such as, for example, a disposable diaper or diaper, a spunbond nonwoven web or a low surface density nonwoven web (pneumatically fabricated nonwoven web or hot rolled nonwoven web) is often used for the reason that it has high tensile strength and excellent machinability and also economical. However, a spunbond nonwoven web or similar fiber completely lacks a sense of roundness due to the manufacturing method, and improving its texture is difficult.

The applicant of the present invention previously proposed a non-woven fabric containing fibers obtained by breaking some long fibers, with only one end of these fibers being bonded using a heat-sealing device, and the free end parts of the fibers at the other end are thick (see Patent Document 1). When using the non-woven fabric described in patent document 1, despite the fact that the tensile strength is high, a roundness feeling is fully present, the cushioning property is improved, and the texture is also improved.

As another product different from the one described above, for example, described in patent document 2, an absorbent product containing a liquid-permeable top sheet, on the back of which a surfactant is applied, which gives a higher degree of hydrophilicity than on the surface side top sheet, without changing the density of the fibers that make up the liquid-permeable top sheet.

LIST OF REFERENCES

PATENT LITERATURE

Patent Document 1: Japanese Patent Application JP2012-92475 A

Patent Document 2: Japanese Patent Application JP2005-87659 A

SUMMARY OF THE INVENTION

TECHNICAL PROBLEM

However, there is no description in Patent Document 1 regarding the aspect that, for example, the nonwoven fabric described in Patent Document 1 is used on the top sheet of an absorbent article, such as a diaper or disposable diaper, quickly moving the body fluid that it absorbs the top sheet, on the side of the absorbent element, and the aspect that the body fluid that is absorbed in the absorbent element hardly returns through the top sheet. In this regard, the improvement of the liquid transmission property with respect to the rapid movement of the absorbed body fluid to the side of the absorbent element and the difficult back flow of the liquid, so that the body fluid that is absorbed are in a compromise relationship, and therefore, providing these properties at the same time becomes difficult. Thus, there is an additional need for coexistence at the same time of the desired improvement in the liquid transmission property and the difficult backflow of the liquid.

In addition, in patent document 2 there is no description of the fibers to be nibbled, and the liquid permeable top sheet described in patent document 2 is a sheet which has completely no cushioning property. In addition, since only the surfactant is simply applied to the liquid-permeable top sheet described in Patent Document 2 in such a way that the density of the constituent fibers does not change significantly, it is difficult to improve the liquid transmission property when moving the body fluid to the side of the absorbent element .

Accordingly, a problem to be solved according to the present invention is to provide a non-woven fabric which improves the cushioning property and also improves the liquid transmission property, and which makes the return flow of liquid difficult.

SOLUTION OF PROBLEMS

The present invention provides a hydrophilic non-woven fabric in which a fibrous structure is present, where long fibers are bonded using a heat-sealing device. This non-woven fabric contains fibers that are obtained by tearing some long fibers, where some end parts of the fibers are bonded with a heat-gluing device, and the other end parts are free end parts protruding from the fiber structure. The degree of hydrophilicity of fibers having free end portions is less than the degree of hydrophilicity of fibers constituting the fiber structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a nonwoven fabric that constitutes an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a fiber having a thick free end portion that the nonwoven web shown in FIG. one.

FIG. 3 is a schematic diagram illustrating a method for measuring the diameter of the distal end of a fiber of the nonwoven fabric shown in FIG. one.

FIG. 4 is a schematic diagram illustrating a method for measuring the number of protruding fibers of the nonwoven fabric shown in FIG. one.

FIG. 5 is a schematic diagram illustrating a suitable nonwoven fabric manufacturing apparatus used in the manufacturing method of the present invention.

FIG. 6 is a schematic representation of the partial tensile processing section with which the manufacturing apparatus of FIG. 5.

FIG. 7 is an enlarged, in the main part, sectional view of the partial tensile processing section shown in FIG. 6.

FIG. 8 is a schematic representation of the pile section with which the manufacturing apparatus of FIG. 5.

FIG. 9 is a view explaining an exemplary applied aspect of the nonwoven fabric of the present invention and an expanded top view illustrating a state in which the disposable diaper is expanded and stretched.

FIG. 10 is a sectional view taken along line I-I of FIG. 9.

DESCRIPTION OF EMBODIMENTS

Next, a nonwoven fabric according to the present invention will be described based on a corresponding preferred embodiment with reference to FIG. 1-4.

The non-woven fabric 1 according to this embodiment (hereinafter also referred to simply as the “non-woven fabric 1") is a hydrophilic non-woven fabric that constitutes the fiber structure 11, where the long fibers 2 are bonded with a heat-sealing device 3, as shown in FIG. 1. The nonwoven fabric 1 contains fibers 20, which is obtained by breaking some long fibers 2, and one end part 20a of the fibers 2 are fastened with a heat-gluing device 3, and the other end parts are free end parts 20b protruding from the fiber structure 11 to be napping (hereinafter also referred to as "fiber 20 having free end portions 20b"). With respect to the nonwoven fabric 1, as shown in FIG. 1, an explanation is given below defining the longitudinal direction of the nonwoven fabric 1 as the Y direction, and also defining the transverse direction of the nonwoven fabric 1 as the X direction. In this regard, with respect to the nonwoven fabric 1, according to the orientation direction of the constituent fibers, the machine direction parallel to the direction fiber orientation coincides with the longitudinal direction (Y direction), while the transverse direction perpendicular to the machine direction coincides with the width direction (X direction), and in In the explanation given, the Y direction and the machine direction mean the same direction, while the X direction and the transverse direction also mean the same direction. In addition, the nonwoven fabric 1 constitutes a fibrous structure 11, which contains fibers 20 having free end portions 20b protruding from the fiber structure 11, loop-shaped fibers 23 protruding in the form of loops between the thermally bonded portions 3, 3 described below (fibers 20 and fibers 23 are collectively referred to as “protruding fibers”), and fibers that are not exposed to bristling, with the exception of “protruding fibers”. The fiber structure 11 is constituted by fibers which are not exposed to nibbling, with the exception of fibers 20 having free end portions 20b that protrude from the fiber structure 11 and loop-shaped fibers 23 that protrude in the form of loops between the thermally bonded portions 3, 3 described later.

In a detailed explanation regarding the non-woven fabric 1 according to this embodiment, the non-woven fabric 1 is a hydrophilic non-woven fabric 10, the fabric being long fibers 2, periodically bonded with a heat-sealing device 3. The hydrophilic non-woven fabric 10 will be described below as the original non-woven fabric ( non-woven fabric material) 10. The non-woven fabric material 10 is a non-woven fabric before some of the long fibers are torn 2. Here, the term "length Fiber "means a fiber with a length of 30 mm or more, and the non-woven fabric material 10 is preferably constituted by so-called continuous long fibers with a fiber length of 150 mm, since then a non-woven fabric 1 having a high tensile strength can be obtained . As such a nonwoven fabric material 10, a spunbond nonwoven web or a laminated nonwoven web having a spunbond layer and an aerodynamically melt layer, a hot-rolled nonwoven web obtained by carding, or the like is used. As a laminated non-woven fabric, for example, a laminated non-woven fabric containing two spunbond layers containing three spunbond layers, a laminated non-woven web containing three spunbond layers and an aerodynamic laminated non-woven layer containing two spunbond layers obtained between them by an aerodynamic method from a melt by way of a melt layer and spunbond layer laminated non-woven fabric, etc.

The hydrophilic material 10 of the nonwoven fabric can be obtained by performing hydrophilizing treatment, for example, by causing the hydrophilizing substance to adhere to the constituent fibers of the nonwoven fabric or by mixing the hydrophilizing substance with the constituent fibers. Thus, a hydrophilic nonwoven fabric 10 is made by hydrophilizing the treatment of hydrophobic long fibers 2.

As the hydrophilizing agent, anionic, cationic, zwitterionic and nonionic surfactants are used, and anionic surfactants such as carboxylate anionic surfactants, sulfonate anionic surfactants containing salts of sulfuric acid esters anionic surfactants can be used. -active substances containing salts of phosphoric acid esters anionic surfactants (in particular, alkyl ester salt phosphoric acid); non-ionic surfactants, such as a mono-ester of a polyhydric alcohol and a fatty acid, such as a sorbitol fatty acid ester, diethylene glycol monostearate, diethylene glycol monooleate, glyceryl monostearate, glyceryl monooleate or a propylene glycol amide monostearate such as erucic acid acid or amide, N- (3-oleyloxy-2-hydroxypropyl) diethanolamine, a compound of polyoxyethylene and hydrogenated castor oil, a compound of polyoxyethylene, sorbitol and bile wax, a compound of polyoxyethylene and sorbitol sesquistearate, a polyoxyethylene monooleate, a compound of polyoxyethylene and sorbitol sorbitan, a polyoxyethylene glyceryl monooleate, a polyoxyethylene monostearate, a polyoxyethylene monolaurate, a polyoxyethylene monooleate, a polyoxyethylene ethyl ether; cationic surfactants such as quaternary ammonium salts, amine salts or amines; zwitterionic surfactants, such as aliphatic derivatives of secondary or tertiary amines containing carboxyl, sulfonate, sulfate or heterocyclic aliphatic derivatives of secondary or tertiary amines, and the like. These are preferred surfactants, and combinations of preferred surfactants should only contain these surfactants, and they may additionally contain other surfactants and the like.

From the point of view of simultaneously ensuring the appropriate values of both parameters (the duration of the fluid passage and the magnitude of the reverse fluid flow), the amount of hydrophilizing substance in the nonwoven fabric 1 is preferably from 0.1 mass. % or more up to 20 mass. % or less and more preferably from 0.3 mass. % or more to 5 mass. % or less with respect to the weight of the nonwoven fabric 1.

An additional material, such as a web-dyeing agent, a special antistatic agent or softener, can be added to the non-woven fabric 10 in addition to the hydrophilizing agent. In particular, when the softener is mixed or applied to the non-woven fabric material 10, the effect of improving the texture during contact with the skin when worn is further enhanced. As a softener, for example, a wax emulsion, a reaction type softener, a silicon-containing compound, a surfactant, and the like can be used. In addition, if necessary, a known substance (contained in a small amount of components) can be added to the emollient as a secondary additive.

Due to the content of the softener, the non-woven fabric 1 made of the non-woven fabric material 10 acquires a good texture, the fluff loss decreases, the friction of the skin relative to the surface of the fabric becomes low, and its tensile strength increases.

The use of a softener in conjunction with the statistical copolymer, which is described below and is a polymer constituting the fibers of the non-woven fabric material 10, is preferable because it enhances the effect of the softener and the formation of sludge due to the use of the statistical copolymer in the non-woven fabric 1 made of non-woven fabric 10 canvases can be reduced using a softener, which is even more preferable in relation to the possibility of obtaining a material having a silky texture by the way.

In addition, when the nonwoven fabric material 10 is manufactured using a laminated nonwoven fabric containing a spunbond layer and a meltblown layer, and the spunbond layer of the nonwoven web material 10 is comprised of a plurality of layers, for example, a meltblown spunbond layer and a spunbond layer a laminated nonwoven web comprising a spunbond layer, a spunbond layer aerodynamically melt layer and a spunbond layer laminated net any web or the like is preferred to knead the softener in only one spinneret layer, and it is possible to knead the softener in all spunbond layers and the like. When the softener is kneaded into one spinneret layer, the application of the process described below with respect to the side of the layer is preferable from the point of view of the possibility of obtaining a non-woven fabric 1 having excellent texture during contact with skin when worn and high tensile strength. Thus, from the point of view of texture during contact with skin when worn and the magnitude of the reverse fluid flow, the manufacture of nonwoven fabric 1 from material 10 of nonwoven fabric, consisting of a single material of spunbond nonwoven fabric, is preferable in comparison with the manufacture of nonwoven fabric 1 from material 10 non-woven fabric, consisting of a laminated non-woven fabric containing a spunbond layer and melt layer obtained aerodynamically.

The constituent fibers of the non-woven fabric material 10 mainly comprise a thermoplastic polymer, and as a thermoplastic polymer, a polyolefin polymer, a polyester polymer, a polyamide polymer, an acrylonitrile polymer, a vinyl polymer, a vinylidene polymer, and the like are used. As the polyolefin polymer, polyethylene, polypropylene, polybutene, and the like are used. Polyethylene terephthalate, polybutylene terephthalate, and the like are used as the polyester polymer. As the polyamide polymer, nylon and the like are used. As the vinyl polymer, polyvinyl chloride and the like are used. Polyvinylidene chloride and the like are used as the vinylidene polymer. One of these various polymers can be used in pure form, and two or more of them can be mixed and used together. Substances denaturing these various polymers can be used. In addition, composite fibers can also be used as the long fibers constituting the nonwoven fabric material 10. As parallel fibers, parallel fibers having a sheath and a core of fibers, having a sheath and a core of eccentrically crimped fibers, separated fibers, and the like can be used. When composite fibers are used, it is preferable to use sheath and core fibers in which the core is made of polypropylene and the sheath is made of polyethylene, because then a soft non-woven fabric can be obtained 1. The fiber diameter of the long fibers 2 before the processing described below is preferably from 5 microns or more to 30 microns or less, and more preferably from 10 microns or more to 20 microns or less.

From the point of view of suitability for spinning, it is preferable that the material 10 of the nonwoven fabric was a polypropylene polymer, which is a polyolefin polymer. From the point of view of smoothness and texture improvement during contact with skin when worn, as well as from the point of view of ease of tearing, it is preferable that the polypropylene polymer contains at least one type of random copolymer, homopolymer, block copolymer in an amount of 5 mass. % or more to 100 mass. % or less, preferably from 25 mass. % or more up to 80 mass. % or less. In addition, these copolymers and homopolymers can be mixed with each other, or an additional polymer can be mixed with them, but a mixture of a polypropylene homopolymer and a random copolymer is preferable, since it is difficult to break the thread. As a result, the crystallinity of the fibers is reduced in such a way that the fibers that are teased become soft, and the texture improves during contact with the skin, while a good balance is achieved between the tensile strength of the nonwoven fabric and the ease of cutting the protruding fibers with a heat sealant such as a stamp. In this way, peeling of the material in the heat-sealing device 3, such as a heat-sealing device such as a stamp, is prevented, the protruding fibers become short, the loss of fluff is difficult, and an excellent appearance can be obtained. In addition, since the distribution of the melting temperature becomes wider, the thermal bonding property is good. In addition, a polymer containing a propylene component as the base with which ethylene or α-olefin is copolymerized is preferred, and a copolymer of ethylene and propylene is more preferred. From the same point of view, As a propylene polymer, it is preferable polymer containing a copolymer of ethylene and propylene in an amount of 5 mass. % or more, and more preferred is a polymer containing this copolymer in an amount of 25 mass. % or more. A copolymer of ethylene and propylene containing ethylene in an amount of from 1 mass is preferred. % or more up to 20 mass. % or less, and in particular, a copolymer of ethylene and propylene containing ethylene in an amount of from 3 wt. % or more up to 8 mass. % or less, from the point of view that there is no stickiness, tensile at break becomes easy, loss of fluff is reduced, and tensile strength is maintained. In addition, from the point of view of environmental protection, it is preferable polypropylene polymer containing regenerated polypropylene in an amount of 50 mass. % or more, and more preferred is a polypropylene polymer containing regenerated polypropylene in an amount of 70 mass. % or more. These conditions remain valid in the case when the non-woven fabric 1 is a laminated non-woven fabric containing a spunbond layer and the layer obtained by the aerodynamic method from the melt.

From the point of view of low cost, the possibility of obtaining excellent texture during contact with the skin when worn and suitable for processing, the surface density of the nonwoven fabric 1, consisting of a material 10 of the nonwoven fabric, is preferably from 5 g / m ² or more to 100 g / m ² or less and more preferably 5 g / m ² or more to 25 g / m ² or less.

Further, in terms of imparting an excellent texture to the nonwoven fabric 1 made as described above, the bulk softness of the nonwoven fabric 1 is preferably 10 cN or less, more preferably 5.9 cN or less, and it is preferably 0.5 cN or more.

In this regard, from the point of view of obtaining a soft material and excellent texture of the non-woven fabric material 10, the bulk softness of the non-woven fabric material 10 is preferably 15 cN or less and more preferably 10 cN or less, and it is preferably 3 cN or more and more preferably 5 cN or more. In particular, the bulk softness of the non-woven fabric material 10 is preferably from 3 cN or more to 15 cN or less, and more preferably from 5 cN or more to 10 cN or less.

Volume softness is measured as follows.

The method of measuring volumetric softness

To measure the volume softness of the nonwoven fabric 1, a sample having a length of 150 mm in the Y direction (longitudinal direction) and a width of 30 mm in the X direction (transverse direction) is cut out from the nonwoven fabric 1 at a temperature of 22 ° C and a relative humidity of 65%, and the edge a sample of nonwoven fabric 1 is fastened in two upper and lower parts in the form of a ring having a diameter of 45 mm using a stapler. In this case, the stapler bracket is located in the Y direction (longitudinal direction).

Using a tensile tester (for example, a Tensilon RTA-100 tensile tester manufactured by Orientec Co., Ltd.), the measured maximum load obtained when the ring is mounted in the form of a cylinder on a test bench was considered as volume softness. and this ring is compressed from above at a compression speed of 10 mm / min with a flat plate approximately parallel to the stand.

In the nonwoven fabric of the present invention, the degree of hydrophilicity of the fibers 20 having free end portions 20b separated and protruding from the fiber structure 11 is less than the degree of hydrophilicity of the fibers constituting the fiber structure 11. The lower the wetting angle of the water, the higher the degree of hydrophilicity . In other words, the fibers 20 having the free end portions 20b are more hydrophobic than the fibers constituting the fiber structure 11, and the fibers 20 show a larger contact angle with deionized water than the fibers constituting the fiber structure 11. In particular, from the point of view of creating obstacles to the backward movement of the body fluid that has been absorbed, the wetting angle of the fibers 20 having free end portions 20b is preferably more than 80 °, more preferably more than 85 ° more preferably 90 ° or more. From the point of view of the quick movement of the body fluid towards the absorbent element, the contact angle of the fibers constituting the fiber structure 11 with deionized water is preferably less than 90 °, more preferably less than 85 °, even more preferably 80 ° or less. From the point of view of a good balance of fluid transmission properties and difficult fluid backflow, the wetting angle of the fibers 20 having free end portions 20b is more than the wetting angle of the fibers constituting the fiber structure 11, with a difference of 5 ° or more, and is more preferable the difference is 10 ° or more. In this regard, the presence of a difference in the values of the contact angles, i.e., a difference in the degree of hydrophilicity means that the difference in the values of the contact angles measured by the measurement method described above is 3 ° or more.

A specific method for measuring the contact angle is as follows. To measure the contact angle, for example, an MCA-J contact angle measurement device manufactured by Kyowa Interface Science Co., Ltd. is used. In particular, immediately after placing 1 drop of water purified by ion exchange on a nonwoven fabric, the volume of which is approximately 20 pl, the measurement of the wetting angle is carried out using a device for measuring the wetting angle. In particular, with respect to the wetting angle of the fibers 20 having free end parts 20b, the cut-off part of the fibers 20 having free end parts 20b is measured. With respect to the wetting angle of the fibers constituting the fiber structure 11, which are not bristled, a different cut part of the fibers is measured than in the case of the fibers 20 having free end parts and loop-shaped fibers 23 protruding between the thermally glued parts 3, 3 in the form of loops in a nonwoven web 1, namely, the cut-off part of the fibers constituting the fibrous structure 11. Each measurement is carried out at five or more points, and the average value of the measurement results at these points is defined as edge wetting angle. The measurement is carried out at a temperature of 22 ° C and a humidity of 65%.

In the non-woven fabric 1, from the point of view of the quick movement of the body fluid towards the absorbent element, the proportion of fibers with an interfiber distance of 150 μm or more and 300 μm or less, preferably 30% of the fibers constituting the non-woven fabric 1 or more preferably 35% or more, even more preferably 40% or more.

The interfiber distance of the nonwoven web 1 is measured using a mercury poromer from Shimadzu Corporation by the method of indentation of mercury according to Japanese industrial standard JIS R 1655. The method of indentation of mercury is a method of obtaining information about the physical form of the fiber structure 11, according to which the size between the fibers constituting the fiber structure is measured 11 (the distance between the fibers) or the volume of the fiber structure 11. The principle of the method of indenting mercury is that yes is attached to the mercury the phenomenon to press mercury between the constituent fibers of the nonwoven fabric 1, which is the subject of measurement, and measure the relationship between the pressure applied at a given time and the volume of the embedded (embedded) mercury. A method for measuring the interfiber distance of a nonwoven web 1 using a mercury poromer will be described herein.

The method of measuring the distance between the fibers that make up the nonwoven fabric 1

First, the nonwoven fabric 1 is cut so as to obtain samples having dimensions of 24 mm × 15 mm. In total, three samples are made, and these excised samples are placed in a sample cell of a mercury poromer from Shimadzu Corporation, so that they do not overlap, and pore volume is measured. In particular, the process of measuring pore volume using the method of indentation of mercury is as follows. Namely, in the process of a gradual change in pressure that is applied to the mercury, the volume of mercury pressed into the pores at a given time is measured; in other words, the pore volume is measured, and the ratio between the pore volume and the pore diameter (distance between the fibers) D calculated according to the following equation (1) is determined. In this case, the core diameter (μm) is defined as the interfiber distance (μm).

In this equation, D is the pore diameter (distance between the fibers), θ is the surface tension of mercury, θ is the contact angle, and P is pressure. Regarding the measurement conditions in the above equation (1), the surface tension of mercury is 482.536 dyne / cm (N / m), the wetting angle is 130 °, and the absolute pressure of mercury is from 0 to 60,000 psi (413.7 MPa).

The resulting curve (differential / integral curve) of the distribution of pore diameters (interfiber distances) of the nonwoven fabric 1 serves as the basis for determining the total volume of pores having a diameter in the range from 0 μm or more to 500 μm or less, as the total volume, and the proportion of pores in which the diameter (interfiber distance) is from 150 microns or more to 300 microns or less, the full volume. The measurements are carried out three times, and the average value of the results of these measurements is defined as the percentage of fibers, the distance between which is from 150 microns or more to 300 microns or less. The measurement is carried out at a temperature of 22 ° C and a humidity of 65%.

From the point of view of preventing tearing of the nonwoven fabric 1 during use and its suitability for processing, the tensile strength of the nonwoven fabric 1 is preferably 5.0 N / 50 mm or more and more preferably from 8.0 N / 50 mm or more to 30, 0 N / 50 mm or less. In this regard, from the point of view of ensuring the tensile strength of the nonwoven fabric 1 at a given level, the tensile strength of the material 10 of the nonwoven fabric is preferably 7.0 N / 50 mm or more and more preferably 10.0 N / 50 mm or more up to 50.0 N / 50 mm or less. According to the napping method, which is described below, in comparison with another napping method, the tensile strength of the manufactured nonwoven fabric 1 hardly becomes less than the tensile strength of the material 10 of the nonwoven fabric. It is preferable that the tensile strength of the nonwoven fabric 1 and the corresponding starting material 10 of the nonwoven fabric in the transverse direction is within the above-mentioned limits. The ratio of the tensile strength of the nonwoven fabric 1 and the material 10 of the nonwoven fabric (the tensile strength of the nonwoven fabric 1 / the tensile strength of the material 10 of the nonwoven fabric) is preferably from 0.5 or more to 1.0 or less, and more preferably from 0.7 or more up to 1.0 or less. Tensile strength is measured as follows.

The method of measuring tensile strength

The test sample is rectangular in shape, having dimensions of 200 mm in the transverse direction and 50 mm in the machine direction, cut out of the nonwoven fabric 1 or material 10 of the nonwoven fabric (e.g., spunbond nonwoven fabric) at a temperature of 22 ° C and relative humidity of 65%. A cut test sample of a rectangular shape is used as the test sample. This test specimen is attached to the clamps of a tensile testing apparatus (such as, for example, a Tensilon RTA-100 tensile testing apparatus manufactured by Orientec Co., Ltd.) so that the direction of tension corresponds to the transverse direction. The distance between the clamps is set equal to 150 mm. The point of maximum load, after reaching which the test specimen breaks under tension at a speed of 300 mm / min, is defined as the tensile strength of the test specimen in the transverse direction. In addition, a rectangular-shaped sample having dimensions of 200 mm in the machine direction and 50 mm in the transverse direction, which is used as the test sample, is cut out for measurements. The test sample is attached to the clamps of the tensile testing apparatus so that the machine direction of the sample corresponds to the direction of stretching. The tensile strength of the test sample in the machine direction is determined according to the same procedure as in the above-described method for measuring the tensile strength in the transverse direction.

The nonwoven fabric 1 is also characterized in that its perceptible texture is excellent in contact with the skin when worn, a surface comprising fibers 20 that have free end portions 20b comes into contact.

Numerous characteristic values representing a texture are traditionally known, in particular, the characteristic value obtained with a KES device manufactured by Kato Tech Co., Ltd. is well known. (see the reference document, “Standardization and Analysis of Sensation” (second edition), by Sueo Kawabata, publication date: July 10, 1980). In particular, to represent the feeling of roundness, mainly three characteristic values of LC (a linear curve of the deformation under compression versus compressive load), WC (amount of work under compression) and RC (compression resistance) are known, which are called "compression characteristics". As for these characteristics, they are calculated by the amount of deformation that occurs during application of a load of 0.49 cN / cm ² (0.50 g / cm ² ) or more to 49.0 cN / cm ² (50.0 gf / cm ² ) or less (for highly sensitive measurements, it is from 0.49 cN / cm ² or more to 9.80 cN / cm ² or less (from 0.50 g / cm ² or more to 10.0 g / cm ² or less)). However, in the case of a very thin fabric, such as a non-woven fabric having a low surface density of 5 g / m ² or more to 25 g / m ² or less, a significant difference does not occur, and thus the correlation with the texture is small . In addition, since the load on contact with the absorbent element during wear is approximately 0.98 cN / cm ² (1.00 gf / cm ² ), the texture is felt at very low load, and on the basis of the idea that the characteristic value of the load , which is less than the traditional load, is a useful indicator of the natural texture, a new characteristic value was determined for the load from 0.29 cN / cm ² (0.3 g / cm ² ) to 0.98 cN / cm ² (1 g / cm ² ) and the corresponding strain value. The characteristic value is shown as a numerical value, truly representing the different textures of the spunbond nonwoven fabric and the pneumatically manufactured nonwoven web, and it can represent the nonwoven web as a new characteristic value representing the texture of the spunbond nonwoven.

Characteristic compression resistance at low load

In the present description, the characteristic compressive resistance at light load is defined as a new characteristic value representing the texture. The measurement is carried out at a temperature of 22 ° C and a relative humidity of 65%. To measure the data that form the basis of the characteristic compressive resistance at light load, a device under the trade name KES FB3-AUTO-A manufactured by Kato Tech Co., Ltd. is used. The test samples are made by cutting three samples from non-woven fabric 1, each of which is 20 cm × 20 cm in size. After that, one test sample from these samples is mounted on the test bench so that its brushed surface (surface containing fibers 20, having free end portions 20b) faces up (when protruding fibers are absent on both surfaces, or when protruding fibers are present on both surfaces, both surfaces are measured, the surface is accepted nce having minimal value). After that, the test sample is compressed between steel plates having a round flat surface with an area of 2 cm ² . The measurement is carried out at a compression speed of 20 μm / s and at a maximum compressive load of 9.80 cN / cm ² (10.0 g / cm ² ), and the measurement is also carried out at the same speed as indicated above during expansion. The measurement is carried out in the compression direction, where the displacement between the steel plates is determined as x (mm), the load is determined as y (cN / cm ² ), and the position of the found load point is determined as x = 0. The value of x increases according to the increase in compression.

The characteristic compression resistance at light load is calculated by determining the strain in the thickness direction at light load from the measurement results (x, y). In particular, with respect to the data of the first load, which is absent during the expansion, from 0.29 cN / cm ² (0.30 g / cm ² ) to 0.98 cN / cm ² (1.00 g / cm ² ), the amount of deformation is determined at a given time, a straight line of approximation is obtained for the ratio of x and y, and the slope of this line at this time is determined as the aforementioned characteristic value, expressed in units of (cN / cm ² ) / mm. Measurement is carried out at three points for one test sample.

As a result, nine points are measured for three samples. Characteristic values are calculated at the corresponding nine points, and their average value is determined as the characteristic compressive strength of the nonwoven fabric at light load.

It was found that the characteristic compression resistance at light load correlates with the texture, and it was also found that there is a strong correlation, in particular when the starting material 10 of the nonwoven fabric is the same. The reduced numerical value of the characteristic compressive strength (at light load) shows the ease of compression at light load, which can be an excellent feeling of texture (in particular, the feeling of roundness) during wear. For example, the aforementioned characteristic compressive resistance of a non-woven fabric starting material 10 (e.g., a spunbond non-woven fabric) that has not been subjected to the processing described below and has a normal surface density in the range of 5 g / m ² or more to 25 g / m ² or less, is from 19.6 (cN / cm ² ) / mm (20.0 (g / cm ² ) or more to 29.4 (cN / cm ² ) / mm (30.0 (g / cm ² ) or less. On the other hand, the surface of the nonwoven fabric 1, which was obtained by performing the processing described below, similar material 10 of the nonwoven web (e.g., spunbond nonwoven fabrics) becomes easily deformable, and the characteristic compressive strength of 17.6 (cN / cm ²⁾ / mm (18.0 (gf / cm ²⁾ / mm) or less. Thus , from a texture point of view, the aforementioned characteristic compressive strength of a nonwoven fabric 1 obtained from a nonwoven fabric starting material 10 (e.g., a spunbond nonwoven fabric) that has a surface density of 5 g / m ² or more to 25 g / m ² or less and which the technologist is exposed processing, is 17.6 (cN / cm ² ) / mm (18.0 (g / cm ² ) / mm) or less, preferably 14.7 (cN / cm ² ) / mm (15.0 (g / cm ² / mm or less), and from the point of view of obtaining a texture close to the excellent texture of a pneumatically fabricated non-woven fabric, it is more preferable 9.80 (cN / cm ² ) / mm (10.0 (gf / cm ² / mm) or less. The lower limit of the aforementioned characteristic compressive strength of the nonwoven fabric 1 obtained from the starting material 10 of the nonwoven fabric (e.g., spunbond nonwoven fabric), which has a surface density of 5 g / m ² or more to 25 g / m ² or less, and which subjected to technological processing, is not limited in a certain way, but is approximately 0.98 (cN / cm ² ) / mm (1.00 (gf / cm ² ) / mm) from the point of view of manufacture. In the process of processing, such as traditional pile processing, it is difficult to carry out technological processing of the original non-woven fabric 10 (in particular, spunbond non-woven fabric) having a low surface density in this range from 5 g / m ² or more to 25 g / m ² or less, to obtain such a characteristic value without a significant decrease in tensile strength.

With respect to the heat-sealable parts 3 of the nonwoven fabric 1, in terms of texture or suitability for processing, the area of each heat-sealable part 3 is preferably from 0.05 mm ² or more to 10 mm ² or less, more preferably from 0.1 mm ² or more to 1 mm ² or less. The number of heat-sealing parts 3 is preferably between 10 / cm ² or more to 250 / cm ² or less, more preferably between 35 / cm ² or more to 65 / cm ² or less. The distance between the centers of the heat-seal parts 3 adjacent to each other in the transverse direction is preferably from 0.5 mm or more to 10 mm or less and more preferably from 1 mm or more to 3 mm or less, and the distance between the centers of the heat-seal parts 3 to each other in the machine direction is preferably from 0.5 mm or more to 10 mm or less, and more preferably from 1 mm or more to 3 mm or less.

The heat-sealable part 3 is a heat-sealable part, which is produced periodically by means of a thermocompression joint, for which embossing (pressure of a relief roller, a flat roller, etc.) is used, the heat-sealable part obtained by ultrasonic bonding, the heat-sealable part, partially connectable by periodic use hot blast, etc. Among them, the heat-sealable part obtained by the thermocompression compound is preferable in that the fibers break easily. The shape of the heat-sealing device 3 is not limited in a specific way, and any shape, for example, such as a circle, rhombus or triangle, can be adopted. The proportion of the total area of heat-sealable parts 3, occupying the area of one surface of the nonwoven fabric 1, is preferably from 5% or more to 30% or less, and more preferably from 10% or more to 20% or less in order to prevent the formation of bald patches.

Non-woven fabric 1 is made of spunbond non-woven fabric, which is, for example, long fibers 2. Fibers 20 are formed (fibers 20 having free end parts 20b), which are obtained by tearing part of the fibers 2, and only one end part 20a of which is fastened by heat-sealing device 3. Fibers 20 include fibers 21 having free end portions 20b (see FIG. 1). In the case of a fiber having a thick distal end, the cross section of the distal end portion is preferably flat (oval or flattened). As a result of this, protruding fibers are obtained having soft distal ends and a non-woven fabric that is characterized by reduced skin irritation when worn. As shown in FIG. 1, fibers 20 in which only one end portion 20a is bonded with a heat-gluing device 3 include fibers 21 in which the free end portions 20b at the other end are thick, and fibers 22 in which the free end portions 20b are not thick. Here, the term “free end part” refers to the “other end part” of the fiber 20, in which only one end part 20a is bonded by a heat-sealing device 3, and, in other words, this is the “distal end part”. The question of whether the free end portion 20b is thick or not is solved by measuring the fiber diameter by the following method of measuring and calculating the degree of increase in the diameter of the distal end of the fiber.

Method for measuring fiber diameter

As shown in FIG. 3 (a), first of all, at a temperature of 22 ° C and relative humidity of 65%, the test sample, measuring 2 cm in the transverse direction and 2 cm in the machine direction, is cut with a sharp blade from the nonwoven fabric 1 for measurement, and the test sample made by bending from the outside along a return line Z extending in the transverse direction through a plurality of heat-sealing parts 3, as shown in FIG. 3 (b), for examination by a scanning electron microscope (SEM), it is mounted and fixed on a sample stand made of aluminum on which a carbon tape is applied, as shown in FIG. 3 (c). After that, ten fibers 20, in which only one of the end parts 20a are bonded with a heat-gluing device 3, are randomly selected from SEM images taken at a magnification of approximately 750 times, and the vicinity of the free end parts of these fibers is captured. In the photographs taken (see FIG. 2), respectively, the diameter 21a of the fiber 20 (the diameters of the fibers 20 in areas other than the free end parts 20b) is measured at positions 120 μm from the far ends of the free end parts 20b. The inclination of the region, which is not the free end portion 20b, during the measurement of the diameter 21a of the fiber 20 moves toward the free end portion 20b in an unchanged form, and the diameter of the fiber 21 (diameter 21b of the fiber 20 in the free end portion 20b) is measured in the thickest position parts of the region between the distal end of the free end portion 20b and in a position located at a distance of 20 μm from the distal end. In this regard, when the distal end portion is flat, a situation arises in which the distal end does not appear thick at a given viewing angle, but the measurement is carried out by means of the photograph obtained, in which case it does not matter.

Fiber 21 having a thick loose end portion 20b means a fiber that satisfies the requirement that the degree of increase in fiber diameter at the far end is 15% or more. The value of the degree of increase in the diameter of the fiber at the far end is calculated using the following equation (2) and knowing the diameter 21b of the fiber 20 in the free end portion 20b and the diameter 21a of the fiber 20 in the region other than the free end portion 20b, which were measured respectively with using photographs of ten fibers 20, pre-selected randomly. From the point of view of the possibility of obstructing the cutting of the fiber between the thermally bonded parts 3 (the part of the fiber shape except for the boundary between the thermally bonded part 3 and the fiber), the possibility of suppressing a decrease in tensile strength and the possibility of obtaining a nonwoven fabric 1 having an excellent texture, the degree of increase in the diameter of the fiber at the far the end is preferably 20% or more and more preferably 25% or more.

In nonwoven fabric 1, in terms of texture balance during contact with skin when worn and tensile strength, and in terms of cushioning, the ratio of fibers 21 having thick free end parts 20b and fibers 20 with only one end parts 20a are bonded with a heat-sealing device 3 (fibers 21, in which the free end parts 20b are thick, and fibers 22, in which the free end parts 20b are not thick), is preferably 20% or more, more preferably 30% or more, even more preferably 40%. The ratio of the fibers 21, in which the free end portions 20b are thick, is determined by calculating the degree of increase in the diameter of the fiber at the far end for ten fibers 20 randomly selected from SEM images taken with an increase of approximately 750 times, respectively, and calculating the ratio of the fibers 21, in which the free end portions 20b are thick using the aforementioned method for measuring fiber diameter.

As shown in FIG. 1, the nonwoven fabric 1 has loop-shaped fibers 23 protruding in the form of loops between the thermally bonded portions 3, 3. The protruding “loop-like fiber 23” means a fiber that does not have a free end portion 20b at the other end, and which protrudes at a portion remote from the return line Z over a distance of 0.5 mm or more when observed as in FIG. 3 (c), in the aforementioned method for measuring fiber diameter. In the present description, the loop-shaped fiber 23 is a protruding loop-shaped fiber. As shown in FIG. 1, the fibers constituting the nonwoven fabric are fibers 20 (fibers 20 having free end portions 20b), in which one end part 20a is attached to the heat-sealable parts 3, and which include fibers 21, whose free end parts 20b are thick, and fibers 22, whose free end parts 20b are not thick, and loop-shaped fibers 23 protruding in the form of loops between the thermally glued parts 3, except for the fibers 20, as well as fibers that are not exposed to napping. The fibrous structure 11 consists mainly of fibers that are not exposed to napping. The average fiber diameter from the number of constituent fibers of the fiber structure 11 is determined by randomly selecting ten fibers that are not nibbled, pruning them and performing the same measurement based on the fiber diameter measurement method described above to determine the average value.

From the point of view of preventing non-woven fabric 1 from sticking to the skin during contact with skin when worn, reducing inconvenience and improving texture, in the fibers forming the non-woven fabric 1, the ratio of loop-like fibers 23 and the total number of fibers 20 (fibers 20 having free end parts 20b ), in which only one end portion 20a is bonded with a heat-sealing device 3, and the loop-like fibers 23 are preferably less than 50%, more preferably 45% or less, even more preferably 40% or less. The ratio of the loop-shaped fibers 23 is determined by randomly selecting ten fibers in SEM images taken at approximately 50 times magnification by subtracting fibers 20 having free end portions 20b (fibers 21 whose free end parts 20b are thick and fibers 22 whose free the end portions 20b are not thick), and loop-shaped fibers 23 from fibers that are randomly selected, and calculating the proportion of fibers 23 (loop-like fibers) in the total number of fibers 21, fibers 22 and fibers 23. In this regard, the results are measured nd also obtained in the same way using SEM images of nine for other areas, and this ratio is calculated by averaging the results of these measurements. Moreover, when one loop-shaped fiber 23 is contained in ten fibers that were randomly selected, the loop-shaped fiber 23 is counted as one fiber.

In the nonwoven fabric 1, from the point of view of filling the space formed between the fibers due to the fact that the constituent fibers have a relatively high degree of freedom, as a result of which the surface roughness decreases and the surface becomes smooth, which leads to an improvement in texture during contact with skin when worn , it is preferable that the degree of dispersion in the distribution of fiber diameters increases, but from the point of view of texture, when the degree of dispersion is 0.33 or more, there may be a floor chen sufficiently satisfactory effect, and when the degree of dispersion in the fiber diameter distribution is 0.35 or more can be obtained still more satisfactory effect. There is no specific upper limit to the degree of dispersion in the diameter distribution of the fibers, but it is preferably 1 or less. The degree of dispersion in the diameter distribution of the fibers is preferably from 0.35 or more to 0.9 or less. The degree of dispersion described in this document in the diameter distribution of fibers means the degree of dispersion in the diameter distribution of fibers for all fibers constituting the nonwoven fabric 1, and is a distribution including all fibers 20 in which only one end portion 20a is bonded with a heat sealant 3, loop-like fibers 23 and fibers in which both end parts are fastened with a heat-gluing device 3 and which do not protrude in the form of loops (fibers that are not affected by technologically processing described below). The degree of dispersion in the distribution of fiber diameters is measured in the following way.

The method of measuring the degree of dispersion in the distribution of fiber diameter

First of all, under conditions of a temperature of 22 ° C and a relative humidity of 65%, the test sample, measuring 2 cm in the transverse direction and 2 cm in the machine direction, is cut with a sharp blade from a non-woven fabric 1 for examination using a scanning electron microscope (SEM) is installed and fixed on a sample stand made of aluminum, on which a carbon tape is applied, without bending the test sample. After that, using SEM images taken at approximately 750 times magnification, ten fibers are randomly selected, and the respective fiber diameters are measured in the regions, excluding the free end portions 20b (in this regard, when the nonwoven fabric 1 to be measured is a laminated nonwoven web containing a spunbond layer and a melt-bed obtained aerodynamically, the fibers obtained by the aerodynamic melt layer are not selected, and only spunbond fibers are selected layer). The diameters of ten fibers are measured on one stand for samples made of aluminum, as described above, the average value d _{ave is} calculated from the measured diameters d1-d10 of ten fibers, and a fiber distribution is obtained for the diameters for ten fibers randomly selected from diameters d1- d10 fibers, and the average value of d _{ave is} calculated by the following equation (3). The unit is micron (μm), and the measurement is carried out with an accuracy of 0.1 μm. For one non-woven fabric, the diameter distribution of the fibers for ten fibers is determined in six positions on a sample stand made of aluminum, and the average diameter value in the distribution of the diameters of ten fibers obtained in each position (see the following equation (4)) is determined as the diameter of the fibers of the nonwoven fabric 1. In this regard, the VARPA function in the Microsoft Corporation EXCEL 2003 spreadsheet software is used to calculate the diameter distribution of the fibers for ten fibers.

The degree of dispersion in the distribution of fibers of the nonwoven fabric 1 = the sum obtained by the above equation (3) of the distributions of ten fibers in diameter (4)

In the nonwoven fabric 1, from the point of view of improving the cushioning property and from the point of view of improving the texture during contact with the skin when worn, the number of protruding fibers is 8 / cm or more and more preferably 12 / cm or more. Here, the protruding fibers comprise fibers 20 having free end parts 20b (fibers 21 whose free end parts 20b are thick and fibers 22 whose free end parts 20b are not thick) and loop-shaped fibers 23 in non-woven fabric 1. From the point of view the possibility of obtaining sufficient tensile strength, the upper limit of the number of protruding fibers is 100 / cm or less and more preferably 40 / cm or less from the point of view of the absence of noticeable fluff, which affects the appearance. The protruding fibers are measured by the following measurement method. As used herein, the term “protruding non-woven fabric” means a non-woven fabric in which the number of protruding fibers is 5 / cm or more when measured by the following method.

The method of measuring the number of protruding fibers

FIG. 4 is a schematic diagram illustrating a method for measuring the number of protruding fibers among the fibers forming the nonwoven fabric 1, at a temperature of 22 ° C. and a relative humidity of 65%. First of all, the test sample, measuring 20 cm × 20 cm, is cut with a sharp blade from a nonwoven fabric to be measured, and, as shown in FIG. 4 (a), the test sample 104 is made by bending from the outside on the protruding surface of the test sample. After that, the test sample 104 is placed on a black A4 substrate, and, as shown in FIG. 4 (b), and then another black A4 substrate is placed on top, in which a hole 107 is drilled having a length of 1 cm and a width of 1 cm. In this case, as shown in FIG. 4 (b), a configuration is obtained in which the fold 105 of the test sample 104 can be seen through the hole 107 in the black substrate located on top. Both substrates used Kenran black paper having a mass of 500 sheets of 265 g and manufactured by Fujikyowa Seishi. After this, loads of 50 g are placed in positions at a distance of 5 cm in the direction from the center from both sides of the hole 107 in the upper substrate along the fold 105, respectively, so that a state is created in which the test sample 104 is completely folded. After that, as shown in FIG. 4 (c), through an opening 107 in the substrate, observation is carried out using a VHX-900 microscope manufactured by Keyence Corporation, magnified by 30 times, and the number of protruding fibers is measured by 1 cm that protrude above an imaginary line 108, which occupies a position on a distance of 0.2 mm upward from the fold 105 of the test sample 104. Nine samples are measured, and the average value (rounded to one decimal place) of the measurement results of nine samples is determined as the number of protruding fibers.

Furthermore, when the number of protruding fibers is determined, for example, in the case where a fiber is present that crosses an imaginary line 108 twice, occupying a position 0.2 mm up from the fold 105, such as the fiber 106a shown in FIG. 4 (c), this fiber counts as two. In particular, in the example shown in FIG. 4 (c), there are four fibers once crossing an imaginary line and one fiber 106a crossing an imaginary line 108, this fiber 106a crossing an imaginary line 108 twice and counted as two, and thus the number of protruding fibers is six.

In non-woven fabric 1, from the point of view of improving texture during contact with skin when worn, the average fiber diameter of the protruding fibers (fibers crossing the imaginary line 108 and including fibers 20 having free end portions 20b and loop-shaped fibers 23) is preferably smaller than the average fiber diameter of the surface fibers in the region in which there are no protruding fibers on the same surface (fibers that do not cross the imaginary line 108 and do not reach the imaginary line and 108, namely, the fibers are not subjected to napping, but constitute the fibrous structure 11). The average fiber diameter is the fiber diameter obtained by measuring the fiber diameter in 12 parts of each of the protruding fibers and fibers that are not exposed to teasing, for which a microscope (optical microscope, scanning electron microscope, etc.) is used. The average fiber diameter of the protruding fibers is preferably from 98% or less to 40% or more, and more preferably from 96% or less to 70% or more with respect to the average fiber diameter of among the fibers that are not tousled, in order to create an excellent textures. Similarly, both the average fiber diameter of the fiber 20 having free end portions 20b and the average fiber diameter of the loop-like fibers 23 are preferably smaller than the average fiber diameter of the number of fibers constituting the fiber structure 11 (fibers that are not exposed teasing), wherein it is preferably from 98% or less to 40% or more, and more preferably from 96% or less to 70% or more in order to create an excellent texture.

In addition, as described above, in the nonwoven fabric 1, it is preferable that the number of protruding fibers (fibers including fibers 20 having free end portions 20b and loop-like fibers 23) is 8 / cm or more, and the protrusion height of the protruding fibers is 1.5 mm or less. As a result of this, an absorbent article can be obtained in which the cushioning property is improved, and there is also an improved texture. From the point of view of obstructing the formation of fluff, and also to make it difficult to fall down, the height of the protrusions of the protruding fibers is preferably 1.0 mm or less. On the other hand, if the height of the protrusions is 0.2 mm or more, a non-woven fabric having an excellent texture is obtained. In addition, from the point of view of decreasing the magnitude of the reverse fluid flow when the body fluid is absorbed, it is preferable that the height of the protrusions is 0.5 mm or more. From the point of view that when the teething surface is used as the side of the surface that comes into contact with the skin when worn, the non-woven fabric is firmly held on the skin when worn, and the sensation is preferred, the height of the protrusions is more preferably 1.0 mm or less. In addition, from the point of view of the possibility of obtaining a non-woven fabric having improved cushioning property and a high absorption rate of the body fluid, it is preferable that the number of protruding fibers is 15 / cm or more. In addition, a case in which the height of the protruding fibers exceeds 5 mm is undesirable because the fibers form in the form of fluff, and thus, when the fibers are abraded during wear, this fluff falls out and bald patches occur. Here, the height of the protruding fibers means the height of the fibers in their natural state without stretching the fibers during the measurement, which is different from the length of the fibers. When the length of the protruding fibers is large, or when the stiffness of the fibers is high, there is a tendency that the height of the protruding fibers also increases. The height of the protruding fibers is measured by the following measurement method.

The method of measuring the height of the protrusion of the protruding fibers

The height of the protruding fibers is measured simultaneously with measuring the number of protruding fibers (fibers including fibers 20 having free end portions 20b and loop-shaped fibers 23). In particular, as shown in FIG. 4 (c), when observed through a hole 107 in the substrate, lines are drawn every 0.05 mm from the fold 105 parallel to it to a position where the protruding fibers do not cross the line. After that, a parallel line is selected, where the number of fibers crossing the parallel line is half the number of protruding fibers measured as described above (definition from an imaginary line 108, located 0.2 mm higher), and the distance from the parallel line to the fold is defined as protrusion height. The above operation is repeated for three samples of nonwoven fabric to be measured at three points for each sample of nonwoven fabric, and then the results obtained for all nine points are averaged, and thus, the protrusion height of the protruding fibers is determined.

In addition to the protrusion height of the protruding fibers and the number of protruding fibers, it is preferable that the bulk softness of the non-woven fabric 1 is 8.0 cN or less in terms of producing a soft material during contact with the skin when worn, and the non-woven fabric 10 has excellent texture. In addition, it is preferable that the bulk softness is from 0.5 cN or more to 3.0 cN or less from the point of view that the non-woven fabric 1 is used as material for the manufacture of products such as baby clothes for infants or young children . Volume softness is measured by the following measurement method.

The method of measuring volumetric softness

To measure the volume softness of the nonwoven fabric 1, this nonwoven fabric 1 is cut so that a sample having 150 mm in the machine direction and 30 mm in the transverse direction is obtained, and the ends of the cut sample of the nonwoven fabric 1 are fastened in two upper and lower parts in the form of a ring having a diameter of 45 mm using a stapler. In this case, the stapler brackets are located in the machine direction. Using a tensile tester (for example, a Tensilon RTA-100 tensile tester manufactured by Orientec Co., Ltd.), the measured maximum load obtained when the ring is mounted in the form of a cylinder on test bench, and this ring is compressed from above at a compression speed of 10 mm / min with a flat plate approximately parallel to the bench. After that, the ring is made by interchanging the machine direction and the transverse direction, and the volumetric softness in the machine direction is measured in the same way. Two rings are made for the machine direction and the transverse direction, and the measurement is carried out in such a way that the average value of the measurement results in the transverse direction and the machine direction is taken as the volume softness of the non-woven fabric 1.

Next, a method for manufacturing a nonwoven fabric 1 will be described. A suitable method for manufacturing a nonwoven fabric 1 will be described with reference to FIG. 5-8. The manufacturing apparatus appropriately used in the method of manufacturing the nonwoven fabric 12 mainly comprises a pre-treatment section 4 and a pile section 5 mounted downstream of the pre-treatment section 4, as shown in FIG. 5. The pretreatment section is also called the “partial stretch processing section”.

As shown in FIG. 5 and 6, in the pre-treatment section 4, a clamping combined stamping roller 43 is installed, consisting of a pair of rollers 41, 42. As shown in FIG. 6, this press combination punching roll 43 comprises cylindrical rolls made of metal such as aluminum alloy, iron or steel, and one roll 41 has a plurality of projections 411 on its peripheral surface, while the second roll 42 has on its peripheral surface the recessed portions 422, which include the protruding parts 411, in positions corresponding to the protruding parts 411 of the first roller 41. In addition, as shown in FIG. 6, the second roller 42 has a plurality of protruding parts 421 on its peripheral surface, and the first roller 41 has on its peripheral surface a recessed part 412, which includes the protruding parts 421 in positions corresponding to the protruding parts 421 of the second roller 42. In addition, as shown in FIG. 6, on the respective peripheral surfaces of the pair of rollers 41, 42, the protruding parts 411, 421 and the recessed parts 412, 422 are staggered. A pair of rollers 41, 42 rotate while engaging with each other during the transmission of the driving force from the drive device (not shown) to the rotating shaft of at least one of the rollers 41, 42. In the manufacturing device according to this embodiment one convex-concave roller 41 and the other convex-concave roller 42 are the same rollers, except that the corresponding protrusions 411, 421 occupy the positions in which the corresponding recessed parts 422, 412 are located. Thus, in the following description concerning the same parts are described mainly, the protruding portions 411 of convex-concave roll 41. Also, for example, as shown in FIG. 5 and 6, transport rollers 44, 45 are used in the pre-treatment section 4 and are used in the process of transporting the non-woven fabric material 10 upstream and downstream with respect to the pressure combination stamping roller 43, the speed of rotation of the pressure combination stamping roller 43 is controlled by a controller (not shown in the drawing) installed in the device for manufacturing.

As shown in FIG. 7, the height h of each protruding part 411 of the roller 41 from the peripheral surface of the roller 41 to the top of the protruding part 411 is preferably between 1 mm or more to 10 mm or less, and more preferably from 2 mm or more to 7 mm or less. The distance (step) between the protrusions 411 adjacent to each other in the direction of the rotating shaft is preferably from 0.01 mm or more to 20 mm or less, and more preferably from 1 mm or more to 10 mm or less, and the distance (step) P1 between the protrusions 411 adjacent to each other in the circumferential direction is preferably from 0.01 mm or more to 20 mm or less, and more preferably from 1 mm or more to 10 mm or less. The shape of the upper surface of each protruding part 411 of the roller 41 is not limited in a particular way, and, for example, a round, polygonal, elliptical or other shape is used, the surface area of each protruding part 411 being preferably from 0.01 mm ² or more to 500 mm ² or less and more preferably from 0.1 mm ² or more to 10 mm ² or less. Each recessed portion 422 of the roller 42 occupies a position corresponding to each protruding part 411 of the roller 41. The engagement depth D between each protruding part 411 of the roller 41 and each protruding part 421 of the roller 42 (the length of the overlapping region of each protruding part 411 and each protruding part 421) (see Fig. 7) is 3.5 mm or more, preferably 3.7 mm or more, more preferably 4 mm or more, and 5 mm or less, preferably 4.8 mm or less, more preferably 4.5 mm or less. In particular, the engagement depth D is from 3.5 mm or more to 5 mm or less, preferably from 3.7 mm or more to 4.8 mm or less, and more preferably from 4 mm or more to 4.5 mm or less.

As shown in FIG. 8, a embossed roller 51 is installed in the pile section 5 having protruding parts 511 on its peripheral surface, and a conveyor roller 52, 53 is installed to transport the nonwoven fabric 10 'which is subjected to pre-treatment, upstream and downstream of the embossed a roller 51. The relief roller 51 rotates by transmitting a driving force from a drive device (not shown in the drawing) to a corresponding rotating shaft.

The height of each protruding portion 511 of the embossed roller 51 from the peripheral surface of the roller 51 to the top of the protruding portion 511 is preferably from 0.001 mm or more to 3 mm or less, and more preferably from 0.001 mm or more to 0.1 mm or less. Since there is a embossed roller having such a small height, the embossed roller 51 also includes a so-called sandblasted roller. The distance (pitch) between the protruding parts 511 located next to each other in the direction of the rotating shaft is preferably from 0.1 mm or more to 50 mm or less, and more preferably from 0.1 mm or more to 3 mm or less, and the distance (step) between the protruding parts 511, located next to each other in the circumferential direction, is preferably from 0.1 mm or more to 50 mm or less, and more preferably from 0.1 mm or more to 3 mm or less. The shape of the upper surface of each protruding portion 511 of the embossed roller 51 is not limited in a particular way, and it can be, for example, a round, polygonal, elliptical shape. The upper surface area of each protruding portion 511 is preferably from 0.001 mm ² or more to 20 mm ² or less, and more preferably from 0.01 mm ² or more to 1 mm ² or less. In this regard, when the embossed roller 51 is a sandblasted roller, the density of the protruding parts 511 is preferably from 1000 / cm ² or more to 3000 / cm ² or less, and more preferably from 1200 / cm ² or more to 2500 / cm ² or less.

In the manufacturing apparatus, where the pre-pressing section 4 and the pile section are installed, has such a configuration that, for example, first, a continuous hydrophilic material 10 of the nonwoven fabric, which is hydrophilic treated, and which is the material of the nonwoven fabric 1, is wound off the coil and passed between a pair of convex-concave rollers 41, 42 of the pressure combination roller 43 by means of transport rollers 44, 45, so that a partial stretching treatment is Many parts of the non-woven fabric material 10 are provided. In particular, in the pre-treatment section 4, as shown in FIG. 5, the non-woven fabric material 10 is deformed by compressing the non-woven fabric material 10 between a pair of rollers 41, 42. From the point of view of preventing hot-melt bonding during deformation between the constituent fibers that form the web, it is preferable that a pair of rollers 41, 42 of a compression combined stamping roller 43, effective heating is not carried out, or pressure-sensitive combined stamping is carried out at a temperature at the level of melting point or less than the component in le components of the fibers constituting the material 10 of the nonwoven fabric, which has a minimum melting point, in particular, at a temperature below the melting point of 70 ° C or more.

After that, as shown in FIG. 5, the non-woven fabric material 10 ', which is subjected to a partial stretching treatment, enters the embossed roller 51 having protruding portions 511 on the peripheral surface by means of transport rollers 52, 53. In the pile section 5, the non-woven fabric material 10' enters the embossed roller and is stretched while some of the long fibers 2 of the non-woven fabric 10 ′ are torn, so that fibers 20 are formed which are more protruding upward than the fiber structure 11 and which have the free end portions 20b protruding from the fibers constituting the fiber structure 11 are formed, and a nonwoven web 1 is obtained in which the degree of hydrophilicity of the fibers 20 having the free end parts 20b is less than the hydrophilicity of the fibers constituting the fiber structure 11. In particular, the surface of the non-woven fabric material 10 ′, which undergoes a partial stretching treatment, enters the embossed roller 51, some of the long fibers 2 are torn, and fibers 20 are formed, which have only one end The parts 20a are bonded to the thermally adhesive parts 3 of the nonwoven web. In the process of forming the fibers 20, the fibers 20 having the free end portions 20b stretch to a much greater extent than the fibers that make up the fiber structure 11 of the main part, where napping is not carried out. Due to this stretching, the degree of hydrophilicity of the fibers 20 having free end portions 20b becomes less than the degree of hydrophilicity of the fibers constituting the fiber structure 11. From the point of view of the efficient formation of fibers 20 shown in FIG. 1, it is preferable that the embossed roller 51 rotates in a direction opposite to the conveying direction of the non-woven fabric material 10 ′, and it turns out that the rotational speed of the embossed roller 51 is 0.3 times or more to 10 times or less with respect to translational speed of the material 10 ′ non-woven fabric. When rotation is performed in the circumferential direction (forward direction with respect to the direction of transportation), it is preferable that the embossed roller 51 rotates at a speed of 1.5 times or more to 20 times or less. Here, the speed of the embossed roller 51 means the peripheral speed on the peripheral surface of the embossed roller 51.

From the point of view of more efficient rupture of some of the long fibers 2 and of more efficient formation 20 shown in FIG. 1 is preferred as shown in FIG. 8 that the position of the conveyor roller 53 is set higher than the position of the embossed roller 51, and the deformed non-woven fabric material 10 'comes into contact with the contact surface of the embossed roller 51 when wrapping at an angle of 10 ° or more to 180 ° or less, and it turns out to be more preferable that the contact occurs when wrapping at an angle of 30 ° or more to 120 ° or less, because it becomes possible to suppress a decrease in the width of the nonwoven fabric 1 due to narrowing.

In this regard, the manufacture of fibers 20 having free end parts 20b on both surfaces of the nonwoven fabric 1 is carried out by additional processing of the surface (back surface) by another embossed roller 51, which differs from the surface of the nonwoven fabric 10 ', which is processed by the embossed roller 51.

The non-woven fabric material 10 partially stretches the pressure-sensitive combination stamping roller 43, the weakened points are formed on the heat-sealable part 3 of the non-woven fabric material 10, and the long fibers 2 are then torn from the weakened points on the surface of the non-woven fabric material 10 'of the non-woven fabric 3 by the embossed roller 5, and as a result of this, fibers 21 having thick free end parts 20b are formed. In addition, fibers 22 are formed having free end portions 20b that are not thick by tearing the long fibers 2 between the thermally glued parts 3, 3 during the surface treatment by the embossed roller 51. In addition, the long fibers 2 are peeled off from the weakened points of the thermally bonded parts 3 by a relief roller 51, and fibers that peel off from the heat-seal parts 3 and protrude in the form of loops between the heat-seal parts 3, 3, comprise loop-shaped fibers 23. A non-woven fabric made e the aforementioned suitable method of manufacturing a non-woven fabric 1 is characterized in that the ratio of the loop-shaped fibers 23 and the fibers 22 that are not thick is less than that for a non-woven fabric made according to the traditional teasing method. Since the non-woven fabric made by the above-mentioned suitable method of manufacturing the non-woven fabric 1 contains a smaller proportion of fibers 22 that are not thick, tensile strength may be maintained.

The reason that the degree of hydrophilicity of the fibers 20 having the free end portions 20b is less than the degree of hydrophilicity of the fibers constituting the fiber structure 11 is because the hydrophilic material 10 of the nonwoven fabric is stretched in the pre-treatment section 4 and the pile section 5, thus that the fibers 20 are stretched to a greater extent than the fibers constituting the fiber structure 11. As described above, from the point of view of changing the degree of hydrophilicity of the hydrophilic material 10 of the nonwoven web made by performing hydrophilizing treatment, so that the amount of hydrophilizing substance is from 0.1 mass. % or more up to 20 mass. % or less with respect to the weight of the nonwoven fabric 1 in the pre-treatment section 4 and the pile section 5, the degree of stretching of the fibers, which is represented by the following equation (8), is preferably from 3% or more to 100% or less and more preferably from 5% or more than 50% or less. The degree of stretching of the fibers can be determined as follows.

The method of measuring the degree of stretching of the fibers

The fiber elongation is calculated by knowing the fiber diameter of the nonwoven fabric 1 before processing (which is equal to the fiber diameter of the number of fibers constituting the fiber structure 11), and the fiber diameter of the number of fibers 20 having free end portions 20b after processing. It is believed that the deformation of the fibers due to stretching is plastic deformation, and it is believed that the volumes before and after processing are constant. When the fiber diameter before processing is D μm, the fiber length before processing is A mm, the fiber diameter after processing is D ′ μm, and the fiber length after processing is A ′ mm, the following equation (5) is satisfied.

The degree of stretching after processing can be represented by the following equation (6) using fiber lengths before and after processing.

According to the above equation (5), the fiber lengths A, A ′ can be represented by the following equation (7), using the fiber diameters D, D ′, and the degree of stretching of the fibers can be represented by the following equation (8) according to equations (5), (7) .

Next, operation and effect will be described when the non-woven fabric 1 described above is used according to an embodiment of the present invention.

As shown in FIG. 1 and 2, the nonwoven fabric 1 according to this embodiment comprises fibers 20 made by tearing some long fibers 2, with only one end portion 20a of the fibers 20 bonded with a heat-sealing device 3, and the other ends thereof being free end portions 20b, such so that the fibers 20 are separated and protrude from the fibrous structure 11 of the main part. Thus, the feeling of roundness is fully ensured, the shock-absorbing property is enhanced, and the texture is improved. In addition, since the nonwoven fabric is made of hydrophilic material 10 of the nonwoven fabric, it is hydrophilic, and since some of the liner fibers 2 are torn on the surface, the liquid transmission property is improved. Since the degree of hydrophilicity of the fibers 20 having free end portions 20b is less than the degree of hydrophilicity of the fibers constituting the fiber structure 11, a fluid that moves from the surface of the fiber structure 11 including the fibers 20 that have the free end parts 20b through the fiber structure 11 , hardly returns from the fiber structure 11 to the surface of the fiber structure 11. Thus, the non-woven fabric 1 is a non-woven fabric that has excellent amor iziruyuschee property and excellent passing property of the liquid, and impedes the backflow of the liquid.

The aforementioned effect is achieved to a greater extent when the contact angle of the fibers 20 having the free end portions 20b with deionized water is more than 80 °, and this effect is achieved even more when the proportion of fibers with an interfiber distance of 150 μm or more than 300 microns or less, of the fibers forming the nonwoven fabric 1, is 40% or more. Furthermore, when the fibers 20 having the free end parts 20b include fibers 21 having the thick free end parts 20b, the roundness feeling is fully improved, and the texture is further improved.

The scope of the nonwoven fabric 1 includes its proper use as a constituent element in an absorbent product, mainly such as a disposable diaper or sanitary napkin. As a constituent element, there are, for example, a top sheet, a bottom sheet, a sheet constituting an outer coating for a disposable diaper, and the like, and in particular, the nonwoven fabric 1 is suitably used as the top sheet of an absorbent article forming skin-facing surface when worn. In addition, the scope of the nonwoven fabric 1 includes its proper use as a cleaning sheet. A disposable diaper comprising a nonwoven fabric 1 will hereinafter be described in detail as an example.

As shown in FIG. 9 and 10, the disposable disposable diaper 100 comprises an absorbent structure 50 including an absorbent member 40 as well as an outer cover 60 located on a non-skin surface of the absorbent structure 50 to fix the absorbent structure 50.

As shown in FIG. 10, the absorbent structure 50 has a liquid-permeable topsheet 70, a liquid-impervious (including water-repellent) bottom sheet 80, and a liquid-retaining absorbent 40 located between the two sheets 70, 80, which is elongated mainly in the longitudinal direction as shown in FIG. 9.

As shown in FIG. 9, in the outer cover 60, there is a rear portion A located at the back when worn, a front portion B located at the front when worn and a crotch portion C located between them in the crotch, both edge parts 6a, 6b of the rear part A and the front part B are connected in such a way that a pair of side joints (not shown in the drawing), a pair of leg openings (not shown in the drawing) and a waist hole (not shown in the drawing) are formed. In addition, the outer cover 60 has an outer sheet 62 forming the outer surface of the diaper, and an inner sheet 61 located on the skin surface of the diaper and partially attached to the outer sheet 62, as well as an elastic element 63 of the waist and elastic elements 64 of the parts legs that form the assembly are located between the two sheets 61, 62 in the parts for the waist and parts for the legs 6d, forming a hole for the waist and holes for the legs.

As shown in FIG. 9, the absorbent structure 50 is positioned so as to extend to the rear portion A of the outer cover 60 and its front portion B, with both longitudinal end parts of the absorbent structure 50 occupying the positions directed in the longitudinal direction inward from both longitudinal end parts of the outer coating 60. As shown in FIG. 10, in the absorbent structure 50, the non-skin-facing surface of the bottom sheet 80 of the absorbent structure 50 is connected to the skin-facing surface of the inner sheet 61 of the outer cover 60 by some bonding method, such as a binder, thermal bonding or ultrasonic bonding.

As shown in FIG. 10, the side cuffs 55, 55, which comprise a liquid-tight or water-repellent substance and a breathable material, are located on both side parts of the absorbent structure 50 in the longitudinal direction. An elastic member 56 for manufacturing a side cuff is positioned and held together in a stretched state near the free end portion of each side cuff 55. The side cuff 55 can prevent leakage in the transverse direction of the absorbent structure 50 since the side of the free end portion protrudes when the diaper is worn. As shown in FIG. 10, the sheet from which the side collar 55 is made is attached between the absorbent member 40 and the bottom sheet 80 so that a portion of the sheet having a predetermined width 55a and extending laterally outward from the absorbent structure 50 forms a non-skin surface of the absorbent member 40. In this regard, this part, having a predetermined width 55a, can be attached between the bottom sheet 80 and the outer cover 60.

The nonwoven fabric 1 according to this embodiment is suitably used as the top sheet 70 of the disposable diaper to be worn 100, which is used on the skin-facing surface when worn. In addition, the nonwoven fabric 1 can also be used as the outer sheet 62 and the inner sheet 61 of the outer cover 60 and the bottom sheet 80, as well as a sheet for manufacturing the side cuff 55. A common element used in an absorbent product, such as a disposable diaper , can be used without limiting the elements of the respective sections when nonwoven fabric 1 is not used. For example, liquid-permeable nonwoven flooring can be used as top sheet 70 understood apertured film laminate corresponding element or the like, and as the backsheet 80 can be used a polymer film laminated member of a resin film and nonwoven fabric, etc. As a sheet for manufacturing the side collar 55, a stretch film, a nonwoven fabric, textile material, a corresponding laminated element, and the like can be used. As the outer sheet 61 and the inner sheet 62, a nonwoven fabric containing the water-repellent substance and the like can be used.

As the absorbent element 40, it is possible to use, without limitation, an element that is conventionally used in an absorbent article, such as a disposable diaper. For example, as an absorbent element 40, an element obtained by wrapping a fibrous structure with a fibrous material, such as cellulose with or without a highly absorbent polymer, with a surface wrapper such as sanitary paper or a permeable non-woven fabric, can be used.

As the elastic member 56 for manufacturing the side cuff, the elastic member 63 of the waist of the elastic member 64 of the leg, the conventional member used in an absorbent article, such as a disposable diaper, can be used without limitation.

For example, you can use stretchable material, which is natural rubber, polyurethane, a styrene-isoprene copolymer, a styrene-butadiene copolymer, an ethylene-α-olefin copolymer, such an ethylene-ethyl acrylate copolymer, and the like.

When the non-woven fabric 1 according to this embodiment is used in the top sheet 70, so that the surface on which the fibers 20 having the free end portions 20b are present is a skin-facing surface when the disposable diaper wearer 100 is worn, an overall roundness feeling is improved the top sheet 70 of the disposable diaper 100, and also the shock absorbing property is enhanced, and the texture is improved. In addition, since the nonwoven fabric 1 is hydrophilic, the body fluid easily passes through the nonwoven fabric 1, moving into the absorbent element 40, and since the degree of hydrophilicity of the fibers 20 having free end portions 20b is less than the degree of hydrophilicity of the fibers that are not they are nibbled and constitute the fibrous structure 11, the body fluid that moves into the absorbent element 40 hardly returns to the surface of the fibrous structure 11 from the fibrous structure and 11.

The nonwoven fabric according to the present invention is not at all limited to the nonwoven fabric 1 according to the embodiment described above, and it can be modified accordingly.

In addition, the manufacturing method of the nonwoven fabric of the present invention is not at all limited to the manufacturing method of the embodiment described above, and it can be modified accordingly.

For example, in the method for manufacturing the nonwoven fabric 1 according to this embodiment described above, except for using the nonwoven fabric material 10 subjected to heat treatment at a lower temperature than the melting temperature of the constituent fibers, at another stage, the heat treatment of the nonwoven fabric material 10 can be carried out at a lower temperature than the melting temperature of the fibers constituting the non-woven fabric material 10 before a partial tensile treatment is carried out otka. In particular, in the apparatus for manufacturing a non-woven fabric 1, the hot blast processing section is located upstream of the partial stretching processing section 4, and the partial stretching processing of the non-woven fabric material 10 subjected to heat treatment in the hot blast processing section is carried out in the process of continuous movement of the material 10 a non-woven fabric between a pair of rollers 41, 42 of a combined pressing stamping roller 43 in a section of a partial tensile treatment 4. By wasp The implementation of heat treatment and partial tensile treatment in successive operations thus can provide the result of the manufacture of non-woven fabric 1 having improved texture quality and improved absorption property.

In relation to the above-described embodiments, the present invention further provides the following non-woven fabric and method for its manufacture.

1. A hydrophilic non-woven fabric, in which there is a fibrous structure, where long fibers are bonded using a heat-gluing device, and which contains fibers obtained by tearing some long fibers, one end of which is bonded with a heat-gluing device, and the other end parts of which are are free end parts located separately and protruding from the fibrous structure, and the degree of hydrophilicity of the fibers having free end parts is lower than the degree of hydrophilicity of the fibers constituting the fiber structure.

2. The non-woven fabric according to the preceding paragraph 1, in which the contact angle of wetting with deionized water fibers having free end parts is more than 80 °.

3. The non-woven fabric according to the preceding paragraph 1 or 2, in which the contact angle of deionized water with fibers having free end portions 20b is preferably more than 80 °, more preferably more than 85 °, even more preferably 90 ° or more.

4. The non-woven fabric according to any one of the preceding paragraphs 1-3, in which the wetting angle of the fibers constituting the fiber structure with deionized water is preferably less than 90 °, more preferably less than 85 °, even more preferably 80 ° or less.

5. The nonwoven fabric according to any one of the preceding paragraphs 1-4, in which the wetting angle of the fibers having free end portions 20b is more than the wetting angle of the fibers constituting the fiber structure, the difference being preferably 5 ° or more, and more preferably 10 ° or more.

6. Non-woven fabric according to any one of the preceding paragraphs 1-5, and in this non-woven fabric, the proportion of fibers in which the interfiber distance is 150 μm or more to 300 μm or less, of the fibers forming the non-woven fabric is 30% or more.

7. The non-woven fabric according to any one of the preceding paragraphs 1-6, in which the proportion of fibers the proportion of fibers in which the interfiber distance is 150 μm or more to 300 μm or less, of the fibers forming the non-woven fabric is preferably 30% or more, more preferably 35% or more, even more preferably 40% or more.

8. Non-woven fabric according to any one of the preceding paragraphs 1-7, and this non-woven fabric contains protruding fibers, including fibers having free end parts, and loop-like fibers protruding in the form of loops between the thermally glued parts.

9. The non-woven fabric according to any one of the preceding paragraphs 1-8, wherein in this non-woven fabric the number of protruding fibers is 8 / cm or more, and the height of their protrusion is 1.5 mm or less.

10. The nonwoven fabric according to the preceding paragraph 9, in which the number of protruding fibers is preferably 8 / cm or more, more preferably 12 / cm or more, and also it is 100 / cm or less, more preferably 40 / cm or less.

11. The nonwoven fabric according to the preceding paragraph 9 or 10, in which the height of the protrusion of the protruding fibers is preferably 0.2 mm or more, more preferably 0.5 mm or more, and it is also preferably 1.0 mm or less.

12. Non-woven fabric according to any one of the preceding paragraphs 1-11, in which the fibers having free end parts include fibers in which the free end parts at the other end are thick.

13. The nonwoven fabric of claim 12, wherein the proportion of fibers in which the free end portions are thick is preferably 20% or more, more preferably 30% or more, even more preferably 40% or more.

14. The nonwoven fabric according to any one of the preceding paragraphs 1-13, in which the average fiber diameter of the number of fibers having free end parts is less than the average diameter of the fiber of the number of fibers constituting the fibrous structure.

15. The nonwoven fabric according to any one of the preceding paragraphs 1-14, in which the average fiber diameter of the number of fibers having free end portions is preferably from 98% or less to 40% or more and is more preferably from 97% or less to 70% or more with respect to the average fiber diameter of the number of fibers constituting the fibrous structure.

16. The non-woven fabric according to any one of the preceding paragraphs 8-15, in which the average fiber diameter of the number of protruding fibers is less than the average fiber diameter of the number of fibers that are not exposed to bristling.

17. The nonwoven fabric according to any one of the preceding paragraphs 8-16, in which the average fiber diameter of the protruding fibers is preferably from 98% or less to 40% or more and is more preferably from 97% or less to 70% or more with respect to the average fiber diameter of the number of fibers that are not exposed to bristling.

18. Non-woven fabric according to any one of the preceding paragraphs 1-17, and in this non-woven fabric, the characteristic compressive resistance at low load is 17.6 (cN / cm ² ) / mm or less, tensile strength in the direction perpendicular to the orientation direction of the long fibers is 5.00 N / 5 cm or more, and the surface density is from 5 g / m ² or more to 100 g / m ² or less.

19. The nonwoven fabric according to the preceding paragraph 18, in which the characteristic compressive strength is 17.6 (cN / cm ² ) / mm or less, preferably 14.7 (cN / cm ² ) / mm or less, more preferably 9.80 (cN / cm ² ) / mm or less.

20. The nonwoven fabric according to any one of the preceding paragraphs 1-19, wherein the nonwoven fabric has a tensile strength of the nonwoven fabric of preferably 5.0 N / 50 mm or more and more preferably 8.0 N / 50 mm or more to 30 , 0 N / 50 mm or less.

21. The non-woven fabric according to any one of the preceding paragraphs 1-20, in which the non-woven fabric material is made by hydrophilizing processing of hydrophobic long fibers.

22. The nonwoven fabric of claim 21, wherein the nonwoven fabric is hydrophilized with a hydrophilizing agent, and the amount of the hydrophilizing agent is preferably from 0.1 mass. % or more up to 20 mass. % or less with respect to the weight of the nonwoven fabric material.

23. The non-woven fabric according to any one of the preceding paragraphs 1-22, and in this non-woven fabric there is a fibrous structure that contains fibers having free end parts, loop-shaped fibers and fibers that are not exposed to napping, with the exception of protruding fibers.

24. The non-woven fabric according to any one of the preceding paragraphs 1-23, in which the bulk softness of the non-woven fabric is preferably 10 cN or less, more preferably 5.9 cN or less, and it is preferably 0.5 cN or more.

25. The nonwoven fabric according to any one of the preceding paragraphs 1-24, wherein the bulk softness of the nonwoven fabric material is preferably 15 cN or less, more preferably 10 cN or less, and it is preferably 3 cN or more, more preferably 5 cN or more.

26. A method of manufacturing a non-woven fabric according to any one of the preceding paragraphs 1-25, and this method includes:

the direction of the hydrophilic non-woven fabric, in which there is a fibrous structure containing long fibers bonded with a heat-gluing device, and which is subjected to hydrophilizing treatment, a pair of convex-concave rollers for partial stretching processing of many parts of the non-woven fabric; and

the direction of the non-woven fabric, which is subjected to partial stretching processing, on a embossed roller having protruding parts on its peripheral surface to stretch and tear some long fibers at the same time and to obtain fibers protruding from the fiber structure having free end parts that stretch to a much greater extent than the fibers that make up the fibrous structure, and as a result, fibers are obtained having free end portions in which the hydrophilicity stump is less than the degree of hydrophilicity of fibers that are not exposed to bristling.

27. A method of manufacturing a nonwoven fabric according to the preceding paragraph 26, in which:

partial stretching treatment is carried out using a pair of convex-concave rollers;

one roller in a pair of convex-concave rollers has many protruding parts on its peripheral surface, and another roller in this pair has recessed parts into which protruding parts fall in positions corresponding to the protruding parts of the first roller; and

the engagement depth between the protruding parts of one roller and the protruding parts of another roller is 3.5 mm or more and 10 mm or less.

28. A method of manufacturing a nonwoven fabric according to the preceding paragraph 26 or 27, in which the engagement depth is 3.5 mm or more, preferably 3.7 mm or more, more preferably 4 mm or more, and it is 5 mm or less, preferably 4 8 mm or less, more preferably 4.5 mm or less.

29. A method of manufacturing a nonwoven fabric according to any one of the preceding paragraphs 26-28, in which in the process of pile processing, the sandblasted roller is used as a relief roller, and the density of the protruding parts of the sandblasted roller is from 1000 / cm ² or more to 3000 / cm ² or less.

30. A method of manufacturing a nonwoven fabric according to the preceding paragraph 29, in which the density of the protruding parts of the sandblasted roller is preferably from 1000 / cm ² or more to 3000 / cm ² or less, preferably from 1200 / cm ² or more to 2500 / cm ² or less.

31. A method of manufacturing a nonwoven fabric according to any one of the preceding paragraphs 26-30, in which the degree of stretching of the fibers is preferably from 3% or more to 100% or less, more preferably from 5% or more to 50% or less.

32. An absorbent product in which the nonwoven fabric according to any one of the preceding paragraphs 1-25 is used as the top sheet.

33. A disposable diaper comprising a top sheet, a bottom sheet and an absorbent element located between these sheets, in which the non-woven fabric according to any one of the preceding paragraphs 1-25 is used as the top sheet.

EXAMPLES

The present invention will now be described in more detail based on examples. However, the present invention is not limited to these examples.

Example 1

As the material of the nonwoven fabric, a spunbond nonwoven web (SSS nonwoven web) was used containing three layers of spunbond nonwoven web consisting of a polypropylene homopolymer and having a surface density of 18 g / m ² , a fiber diameter of 16 μm and a ratio of the area of heat-sealable parts (heat-sealable parts) obtained by stamping) 9%, and hydrophilized by the addition of hydrophilizing substances in an amount of 1 mass. % The bulk softness of the nonwoven web was 9.6 cN. Non-woven fabric was made by using non-woven fabric and the implementation of partial tensile processing and nap processing. For the partial stretching treatment, a compression combined stamping roller 43 was used. The height of each protruding part 411, 421 of the roller 43 was 5.0 mm, and the engagement depth D between each protruding part 411 of the roller 41 and each protruding part 421 of the roller 42 was 4.0 mm .

In addition, the distance (step P2) between the protruding parts 411, 421 located next to each other in the direction of the rotating shaft was 7 mm, and the distance (step P1) between the protruding parts 411, 421 located next to each other in the circumferential direction was 7 mm. The temperature of the press combination punching roller 43 was 26 ° C, the peripheral speed of the press combination punching roller 43 was 20 m / min, and the translational speed of the nonwoven fabric was 20 m / min. In addition, a sandblasted roller in which the height of each protruding portion 511 was 0.2 mm and the density of the protruding portions was approximately 2000 / cm ^{2 was} used as the embossed roller 51 for the nap treatment. The translational speed of the nonwoven fabric material was 20 m / min, and the embossed roller 51 was rotated in the opposite direction with respect to the conveying direction of the nonwoven fabric at a peripheral speed twice the translational speed of the nonwoven fabric. The wrapping angle was 60 °. The disposable diaper in Example 1 was made by removing the top sheet from the Merries Panties product manufactured under the registered Merries trademark of Kao Corporation using a non-woven fabric made as described above instead of the top sheet and positioning the non-woven fabric so that the surface a non-woven fabric containing protruding fibers was in contact with the skin when worn.

Example 2

In Example 1, after a partial stretching treatment for nap processing, a sandblasted roller was used, which was a relief roller 51 and rotated in the opposite direction with respect to the direction of transportation of the nonwoven fabric at a peripheral speed exceeding the translational speed of the nonwoven fabric by 4 times. Except as described above, the disposable diaper in Example 2 was made in the same manner as in Example 1.

Example 3

In Example 1, the engagement depth D of the respective protruding parts 411 of the roller 41 and the corresponding protruding parts 421 of the roller 42 in the compression combination stamping roller 43 used for the partial tensile treatment was 3.5 mm, and the sandblasted roller, which was a relief roller 51 used for teasing, rotated in the opposite direction with respect to the direction of transportation of the non-woven fabric with a peripheral speed exceeding twice the translational speed of the non-woven on the web. Except as described above, the disposable diaper in Example 3 was made in the same manner as in Example 1.

Example 4

In Example 1, the engagement depth D of the respective protruding parts 411 of the roller 41 and the corresponding protruding parts 421 of the roller 42 in the compression combination stamping roller 43 used for the partial tensile treatment was 4.5 mm, and the sandblasted roller, which was a relief roller 51 used for teasing, rotated in the opposite direction with respect to the direction of transportation of the non-woven fabric with a peripheral speed exceeding twice the translational speed of the non-woven on the web. Except as described above, the disposable diaper in Example 4 was made in the same manner as in Example 1.

Example 5

A spunbond nonwoven web (SSS nonwoven web) was used containing three layers of spunbond nonwoven web consisting of a polypropylene homopolymer and having a surface density of 17 g / m ² , a fiber diameter of 15 μm and a ratio of the area of heat-sealable parts (heat-sealable parts obtained by stamping) 17 %, and hydrophilized by the addition of hydrophilizing substances in an amount of 1 mass. % The bulk softness of the nonwoven web was 5.0 cN. A nonwoven web was used, the engagement depth D of the respective protruding parts 411 of the roller 41 and the corresponding protruding parts 421 of the roller 42 in the pressure combining stamping roller 43 used for the partial stretching treatment was 4.5 mm, and the sandblasted roller, which was embossed the roller 51 used for teasing, rotated in the opposite direction with respect to the direction of transportation of the nonwoven fabric with a peripheral speed exceeding four times Non-woven fabric staging speed. Except as described above, the disposable diaper in Example 5 was made in the same manner as in Example 1.

Example 6

A spunbond nonwoven web (SSS nonwoven web) was used containing three layers of spunbond nonwoven web consisting of a polypropylene homopolymer and having a surface density of 17 g / m ² , a fiber diameter of 16 μm and a ratio of the area of heat sealable parts (heat sealable parts obtained by stamping) 17 %, and hydrophilized by the addition of hydrophilizing substances in an amount of 1 mass. % The bulk softness of the nonwoven web was 12 cN. A nonwoven web was used, the engagement depth D of the respective protruding parts 411 of the roller 41 and the corresponding protruding parts 421 of the roller 42 in the pressure combining stamping roller 43 used for the partial stretching treatment was 4.5 mm, and the sandblasted roller, which was embossed the roller 51 used for teasing, rotated in the opposite direction with respect to the direction of transportation of the nonwoven fabric with a peripheral speed exceeding four times Non-woven fabric staging speed. Except as described above, the disposable diaper in Example 6 was made in the same manner as in Example 1.

Reference example 1

In Example 1, the engagement depth D of the respective protruding parts 411 of the roller 41 and the corresponding protruding parts 421 of the roller 42 in the compression combination stamping roller 43 used for the partial tensile treatment was 2.7 mm, and the sandblasted roller, which was a relief roller 51 used for teasing, rotated in the opposite direction with respect to the direction of transportation of the non-woven fabric with a peripheral speed exceeding twice the translational speed of the non-woven on the web. Except as described above, the disposable diaper in Reference Example 1 was made in the same manner as in Example 1.

Comparative Example 1

The nonwoven fabric material used in Example 1 was used in place of the top sheet removed from the Merries Panties product manufactured under the registered Merries trademark of Kao Corporation, and a disposable diaper was made in Comparative Example 1.

Reference Example 2

Spunbond nonwoven fabric containing three layers of spunbond nonwoven fabric consisting of a polypropylene homopolymer and having a surface density of 18 g / m ² , a fiber diameter of 16 μm and an area ratio of heat-sealable parts (heat-sealable parts obtained by stamping) 9%, and non-hydrophilized (non-woven fabric made up the non-woven fabric material used in example 1, but it was not hydrophilized), they were used in place of the top sheet removed from the “Merries panties” product manufactured under registered goods by Merries by Kao Corporation, and a disposable diaper was made in Comparative Example 2.

Quality control

Regarding the non-woven fabric used in the top sheet of disposable diapers in Examples 1-6, Reference Example 1 and Comparative Examples 1 and 2, the corresponding measurements were carried out using, as a basis, the above-described method for measuring volume softness, the above-described method for measuring the contact angle the above-described method for measuring the interfiber distance, the above-described method for measuring the tensile strength, the above-described method for measuring at low load, the above-described method for measuring fiber diameter, the method described above the fiber diameter distribution measuring method described above and measuring the number of projecting fibers. These results are presented in the following table 1.

In addition, with respect to the nonwoven fabric used in the topsheet of disposable diapers in Examples 1-6, Reference Example 1 and Comparative Examples 1 and 2, the texture was evaluated using the following method. This assessment was carried out at room temperature (22 ° C) and relative humidity of 65%. These results are presented in the following table 1.

In addition, with regard to disposable diapers in examples 1-6, reference example 1 and comparative examples 1 and 2, the absorption capacity and the property of obstruction of the reverse flow of fluid was evaluated using, respectively, the following methods. This assessment was carried out at room temperature (22 ° C) and relative humidity of 65%. These results are presented in the following table 1.

Texture rating

Regarding the non-woven fabric used in the top sheet of disposable diapers in examples 1-6, reference example 1 and comparative examples 1 and 2, the organoleptic assessment of the texture (smoothness) of the surface of the non-woven fabric on a ten-point scale (the texture improves when the rating approaches 10 points) in comparison with the nonwoven fabric in comparative example 1 (5 points), 10 specialists were carried out, and the average value of the ratings of all three sheets for each nonwoven fabric was calculated with rounding to integers.

Absorption Capacity Assessment

Assemblies below the waist and leg assemblies were removed from each of the disposable diapers in Examples 1-6, Reference Example 1 and Comparative Examples 1 and 2, and the disposable diaper was fixed in its expanded state so that the top sheet was on top. An acrylic plate with a cylindrical liquid filling device was mounted on the top sheet, and weights of 2 kg were placed on the back and on the front of the diaper on the acrylic plate so that the load was applied to the back and to the front. The device for pouring liquid, which was in the acrylic plate, had a cylindrical shape with a height of 53 mm and an inner diameter of 36 mm, and a through hole having an internal diameter of 36 mm, through which the inner space of the cylindrical device for pouring liquid was connected to each other and facing the top sheet of the surface of the acrylic plate, and the axial line of the through hole passed through the center of the cylindrical device for pouring liquid, was made in an acrylic plate in 1/3 position in the longitudinal direction of the acrylic plate and in a central position in its transverse direction. The acrylic plate was positioned so that the center line of the cylindrical liquid filling device in the acrylic plate passed 125 mm from the distal end of the end portion of the cover sheet covering the absorbent core of the diaper from the front side in the longitudinal direction, and physiological saline was poured in a total amount of 160 The physiological solution was poured four times in an amount of 40 g each time at intervals of 10 minutes in a batch mode. The duration of absorption by the diaper of the total amount of 160 g was measured. For each disposable diaper, the average of the results of the three measurements was rounded to the nearest whole number and considered as the duration of absorption. These results are presented in the following table 1.

Evaluation of the properties of the obstacle to the reverse flow of fluid

After evaluating the absorption capacity described above, each of the disposable diapers in Examples 1-6, Reference Example 1 and Comparative Examples 1 and 2 was kept for 10 minutes in a state in which saline was poured onto it in a total amount of 160 g. After that, acrylic the plate was removed, and 16 sheets of 5C filter paper manufactured by Toyo Roshi Kaisha, Ltd., were stacked on a saline solution absorption area, and then a load was applied for 2 minutes to force the filters absorbing saline paper. The load was set so that a weight of 3.5 kg was on an area of 10 cm × 10 cm. The load was removed after 2 minutes, and the weight of filter paper, which absorbed physiological saline, was measured. The value obtained by subtracting the mass of filter paper before absorption from the mass measured after absorption was taken as the value of the return fluid flow for each diaper. For each disposable diaper, the average of the results of three measurements was rounded to the nearest whole number and considered as the magnitude of the reverse fluid flow. These results are presented in the following table 1.

As the results shown in Table 1 clearly show, it was found that in the nonwoven webs in Examples 1-6, the hydrophilic protruding fibers become hydrophobic due to the treatment, and the absorption capacity and the property of obstructing the backflow of liquid are improved compared to the nonwoven webs in comparative example 1.

In addition, it was found that the nonwoven webs in examples 1-6 have an improved cushioning property compared to nonwoven webs in comparative examples 1 and 2.

Accordingly, it was found that the nonwoven webs in Examples 1-6 are nonwoven webs that have an improved cushioning property and inhibit the reverse flow of liquid, and also have an improved liquid transmission property compared to nonwoven webs in Comparative Examples 1 and 2.

INDUSTRIAL APPLICABILITY

According to the present invention, a non-woven fabric is provided that improves the cushioning property, and the liquid transmission property is improved, and the reverse flow of the liquid is hindered.

Claims (13)

1. A hydrophilic non-woven fabric in which there is a fibrous structure where long fibers are bonded using a heat-gluing device, including fibers obtained by tearing some long fibers, one end of which is bonded with a heat-gluing device and the other end parts of which are free end parts located separately and protruding from the fibrous structure, where the degree of hydrophilicity of fibers having free end parts is lower than hydrophilicity of the fibers that make up the fiber structure. 2. The nonwoven fabric according to claim 1, in which the contact angle of deionized water with fibers having free end parts is more than 80 °. 3. The non-woven fabric according to claim 1, in which the proportion of fibers for which the interfiber distance is 150 μm or more and 300 μm or less, among the fibers forming the non-woven fabric is 30% or more. 4. The nonwoven fabric according to claim 1, in which the nonwoven fabric contains protruding fibers, including fibers having free end parts, and loop-like fibers protruding in the form of loops between the thermally glued parts. 5. The nonwoven fabric according to claim 1, wherein in this nonwoven fabric the number of protruding fibers is 8 / cm or more, and the height of their protrusion is 1.5 mm or less. 6. The nonwoven fabric of claim 1, wherein the fibers having free end parts include fibers in which the free end parts at the other end are thick. 7. The nonwoven fabric of claim 1, wherein the average fiber diameter of the number of fibers having free end portions is less than the average fiber diameter of the number of fibers constituting the fiber structure. 8. The non-woven fabric according to claim 1, wherein the non-woven fabric has a characteristic compressive resistance at light load of 17.6 (cN / cm ² ) / mm or less, tensile strength in the direction perpendicular to the orientation direction of the long fibers is 5, 00 N / 5 cm or more, and a surface density of 5 g / m ² or more and 100 g / m ² or less. 9. A method of obtaining a nonwoven fabric according to claim 1, including:
the direction of the hydrophilic non-woven fabric, in which there is a fibrous structure containing long fibers bonded with a heat-gluing device, and which is subjected to a hydrophilizing treatment, on a pair of convex-concave rollers for partial stretching processing of many parts of the non-woven fabric; and
the direction of the non-woven fabric, which is subjected to partial stretching processing, on a embossed roller having protruding parts on its peripheral surface in order to stretch and simultaneously tear some long fibers to produce protruding fibers from the fiber structure and form fibers having free end parts, which stretch significantly more than the fibers that make up the fiber structure, and as a result, fibers having free con evye portion in which the degree of hydrophilicity is less than the degree of hydrophilicity of the fibers which do not undergo napping. 10. A method of obtaining a nonwoven fabric according to claim 9, in which:
partial stretching treatment is carried out using a pair of convex-concave rollers;
one roller in a pair of convex-concave rollers has many protruding parts on its peripheral surface, and another roller in this pair has recessed parts into which protruding parts fall in positions corresponding to the protruding parts of the first roller; and
the engagement depth between the protruding parts of one roller and the protruding parts of another roller is 3.5 mm or more and 10 mm or less. 11. The method of producing a nonwoven fabric according to claim 9, in which during the pile processing, the sandblasted roller is used as a relief roller, and the density of the protruding parts of the sandblasted roller is 1000 / cm ² or more and 3000 / cm ² or less. 12. An absorbent product in which the nonwoven fabric according to claim 1 is used as the top sheet. 13. A disposable diaper comprising a top sheet, a bottom sheet and an absorbent element located between these sheets, wherein the non-woven fabric of claim 1 is used as the top sheet.

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