JP6350722B2 - Composite fiber - Google Patents

Description

  The present invention relates to a composite fiber, and in particular, to a user's body, such as a diaper, a sanitary product, and a hygiene product such as a side sweat pad, a worn product such as disposable clothing, and a sheet or mat-like product such as bedding. The present invention relates to a composite fiber for a nonwoven fabric that is used along and / or in contact and is suitable for applications that are susceptible to deformation during use due to user movement.

  Conventionally, non-woven fabrics are used for disposable items such as disposable diapers and sanitary products. In use, the nonwoven fabric for such use comes into contact with the user's skin or the outside such as clothes and bedding. Therefore, various physical properties corresponding to the application are required.

  For example, Patent Document 1 discloses that a non-woven fabric that forms a portion that directly contacts the skin of a paper diaper requires a smoothness, softness, strain, swelling, and the like. Patent Document 1 proposes a method for evaluating the texture of a nonwoven fabric by a correlation equation using mechanical properties such as tensile properties, bending properties, shear properties, surface properties, and torsion properties as parameters.

  For example, Patent Document 2 discloses a disposable garment having a “cloth-like” backsheet that has less fuzz even if friction with adjacent articles such as clothes and bedding is caused by the movement of the wearer, and the user's body throughout the entire period of use. It is disclosed that there is a demand for an elastic laminate product that provides a good wearing condition to the skin. Patent Document 2 proposes a non-woven fabric layer composed of core-sheath composite fibers having a specific ethylene-propylene random copolymer in the sheath portion in order to solve the problem.

  Patent Document 3 proposes a nonwoven fabric having a small surface roughness and excellent surface smoothness, and a method for producing the same, as a nonwoven fabric suitable for applications such as separators for prismatic batteries, for example.

JP-A-2005-428 Japanese Patent No. 4610831 Japanese Patent Laid-Open No. 10-325059

  Non-woven fabrics used in the field of sanitary products such as diapers, sanitary products, armpit sweat pads, and disposable clothing items are displaced and twisted due to the movement of the user during use, resulting in wrinkling May end up. When these wrinkles are in contact with body parts such as the crotch and armpits, users of hygiene products and disposable clothing may feel uncomfortable or, in some cases, irritate the skin where they come into contact. Sometimes. Therefore, there is a demand for a bulky nonwoven fabric that is comfortable to touch even when it comes into contact with a body part. However, Patent Documents 1 to 3 do not describe such problems and the means for solving them.

  An object of this invention is to provide the composite fiber which can provide the bulky nonwoven fabric with a pleasant touch.

  The conjugate fiber according to the present embodiment for solving the above problems has the following aspects.

  A composite fiber comprising a first component and a second component which are fiber-forming components, wherein the first component and the second component are each composed mainly of a thermoplastic resin, and the first component Includes a long-chain branched polyolefin resin, and the long-chain branched polyolefin resin has a melt flow rate (MFR) of 4 g / 10 min or more measured at a load of 2.16 kg and a temperature of 230 ° C. according to ASTM D1238. A composite fiber characterized by being.

  According to the composite fiber according to the present embodiment, it is possible to provide a bulky nonwoven fabric having a good touch. The non-woven fabric should be suitably used for hygiene products such as diapers, medical uses, other mat-like and sheet-like uses, in particular, top sheets for absorbent articles, and core wrap sheets for core wrap type absorbers. Can do.

It is a cross-sectional view which shows the example of the composite fiber by this Embodiment. It is a figure which shows the example of the manufacturing apparatus which can be used for manufacture of the composite fiber and nonwoven fabric by this Embodiment. It is a table | surface which shows the constituent material of the composite fiber in an Example and a comparative example. It is a table | surface which shows the compounding ratio of the structural material of the composite fiber in an Example and a comparative example. It is a table | surface which shows the structure of the nonwoven fabric in an Example and a comparative example, and the spinnability of a composite fiber. It is a table | surface which shows the result of the test about an Example and a comparative example. It is a figure which shows the example of the diaper manufactured from the nonwoven fabric using the composite fiber by this Embodiment. It is the figure which looked at the lower half body which wore the diaper shown in FIG. 7 from the back side. It is the stereographic projection figure which expand | deploys the diaper shown in FIG. 7, and shows in a decomposition | disassembly state. It is the top view which looked at the absorber of a diaper shown in Drawing 7 from the near side of a top sheet. It is sectional drawing which cut | disconnected the diaper shown in FIG. 7 by the XI-XI line. It is a fragmentary sectional view showing a modification of composition of an absorptive article by this embodiment. It is a fragmentary sectional view showing a modification of composition of an absorptive article by this embodiment. It is a fragmentary sectional view showing a modification of composition of an absorptive article by this embodiment.

<Composite fiber>
The composite fiber according to the present embodiment includes a first component and a second component that are fiber forming components. Each of the first component and the second component has a thermoplastic resin as a main component. The first component includes a long-chain branched structure polyolefin resin. The long chain branched polyolefin resin has a melt flow rate (MFR) of 4 g / 10 min or more measured at a load of 2.16 kg and a temperature of 230 ° C. in accordance with ASTM D1238. The composite fiber having such a configuration is a crimped fiber having crimpability. In the present specification, the “crimpability” of a fiber refers to the property of the fiber being compressed and twisted. The “crimped fiber” refers to a fiber that has a crimp property and is not straight, for example, a spiral, a crimp, or the like. Below, the composite fiber by this Embodiment is demonstrated in detail.

(First ingredient)
The first component is mainly composed of a thermoplastic resin. That is, the first component can contain the thermoplastic resin in an amount of 90% by mass or more and 100% by mass or less based on the total solid content of the first component. Examples of the thermoplastic resin applicable to the first component include polyolefin resins such as polypropylene (PP) and polyethylene (PE). From the viewpoint of spinnability and strength of the composite fiber, polypropylene (PP) is preferably used as the thermoplastic resin.

  In the present embodiment, the first component includes a long-chain branched structure polyolefin resin as one kind of thermoplastic resin. The first component contains the long-chain branched polyolefin resin in an amount of 0.5% by mass or more, more preferably 1% by mass or more based on the total solid content of the first component. The first component is a long chain branched structure polyolefin resin in an amount of 10% by mass or less, more preferably 5% by mass or less, more preferably 3% by mass or less, based on the total solid content of the first component. Including. That is, the first component includes at least two types of thermoplastic resins, that is, a long-chain branched structure polyolefin resin and a thermoplastic resin that is not a long-chain branched structure polyolefin resin. Three or more types of thermoplastic resins as the first component can be used in combination. When the long-chain branched structure polyolefin in the first component is less than 0.5% by mass, the effect of increasing the degree of crimping of the composite fiber is reduced, and when it is more than 10% by mass, the spinnability is lowered. .

  In the present specification, the “long-chain branched polyolefin resin” refers to a polyolefin resin having a structure in which a long side chain is branched from a linear polymer. In this specification, the “long side chain” means a carbon chain having 12 or more carbon atoms constituting one side chain. The long-chain branched polyolefin resin has a structure in which long side chains are branched, so that fluidity in a molten state is lowered. Therefore, if spinning is performed using a thermoplastic resin containing a long-chain branched polyolefin resin as a raw material, when the yarn extruded from the spinning die is drawn by drawing air, the molecular orientation of the yarn tends to advance and the crystal Is promoted. The crystallization of one of the fiber-forming components of the composite fiber is accelerated and hardened, so that the difference in elasticity with the other increases, so that the composite fiber containing the long-chain branched structure polyolefin resin is crimpable The degree of. Moreover, the nonwoven fabric using the composite fiber which mix | blended long-chain branched structure polyolefin resin is easy to be bulky, is excellent in cushioning properties, and becomes difficult to wrinkle even if it receives shear deformation.

  Here, the higher the compounding ratio of the long-chain branched structure polyolefin resin in the first component, the greater the degree of crimping of the resulting composite fiber. Moreover, the nonwoven fabric using this tends to be bulky and has a high cushioning property and is difficult to wrinkle. On the other hand, the higher the compounding ratio of the long-chain branched polyolefin resin in the first component, the lower the spinnability of the produced composite fiber. Therefore, the blending ratio of the long-chain branched structure polyolefin resin can be set in consideration of the spinnability of the composite fiber and the physical properties of the nonwoven fabric using the composite fiber.

  The long-chain branched structure polyolefin resin applicable to the first component preferably has a melt flow rate (MFR) measured at a load of 2.16 kg and a temperature of 230 ° C. in accordance with ASTM D1238 of 4 g / 10 min or more. . As the long-chain branched structure polyolefin resin applicable to the first component, commercially available products (for example, without limitation, for example, melting point 162 ° C., long-chain branched structure polyolefin resin with MFR 8 g / 10 min, and melting point 162 ° C., MFR 4 g / 10 min long chain branched structure polyolefin resin) can be suitably used. If the MFR of the long-chain branched polyolefin resin is lower than 4 g / 10 min, the spinnability of the yarn made from a thermoplastic resin containing this as a raw material is significantly lowered. When a polypropylene resin is used as the long-chain branched polyolefin resin, it is preferable to use a polypropylene resin as the first component thermoplastic resin from the viewpoint of compatibility and the like.

A low crystalline polyolefin resin can be used in combination as the thermoplastic resin of the first component. For example, the low crystalline polyolefin resin satisfying the following a) to g) can be contained in an amount of 5% by mass or more and 50% by mass or less based on the total solid content of the first component.
a) Mesopentad fraction [mmmm] is 30 mol% or more and 80 mol% or less.
b) Racemic pentad fraction [rrrr] and 1− [ mmmm] satisfy the relationship [rrrr] / 1− [ mmmm] ≦ 0.1.
c) Racemic meso racemic meso pentad fraction [rmrm] exceeds 2.5 mol%.
d) Mesotriad fraction [mm], racemic triad fraction [rr], and triad fraction [mr] satisfy the relationship [mm] × [rr] / [mr] ² ≦ 2.0.
e) The weight average molecular weight [Mw] is 10,000 or more and 200,000 or less.
f) The weight average molecular weight [Mw] and the number average molecular weight [Mn] satisfy the relationship of molecular weight distribution [Mw] / [Mn] ≦ 4.
g) The amount of the extract by boiling diethyl ether is 0% by mass or more and 10% by mass or less based on the total solid content of the low crystalline polyolefin resin.

  As the low crystalline polyolefin resin applicable to the first component, commercially available polypropylene (for example, for the purpose of illustration and not limitation, for example, a melting point of 52 ° C. and a MFR of 50 g / 10 min) can be suitably used.

  The low crystalline polyolefin resin is difficult to produce crystals because the side chain protruding directions are not uniform, and the fibers and nonwoven fabrics using the low crystalline polyolefin resin tend to be soft, small and soft to the touch.

(Second component)
The second component is mainly composed of a thermoplastic resin. Specifically, the second component includes the thermoplastic resin in an amount of 90% by mass or more and 100% by mass or less based on the total solid content of the second component.

  Examples of the thermoplastic resin applicable to the main component of the second component include polyolefin resins such as polypropylene (PP) and polyethylene (PE). One type of thermoplastic resin may be used, or two or more types may be used in combination. From the viewpoint of spinnability and strength of the composite fiber, polypropylene (PP) can be preferably used as the thermoplastic resin.

As the second component thermoplastic resin, a low crystalline polyolefin resin can be used in combination. For example, the low crystalline polyolefin resin satisfying the following a) to g) can be contained in an amount of 5% by mass or more and 50% by mass or less based on the total solid content of the second component.
a) Mesopentad fraction [mmmm] is 30 mol% or more and 80 mol% or less.
b) Racemic pentad fraction [rrrr] and 1− [ mmmm] satisfy the relationship [rrrr] / 1− [ mmmm] ≦ 0.1.
c) Racemic meso racemic meso pentad fraction [rmrm] exceeds 2.5 mol%.
d) Mesotriad fraction [mm], racemic triad fraction [rr], and triad fraction [mr] satisfy the relationship [mm] × [rr] / [mr] ² ≦ 2.0.
e) The weight average molecular weight [Mw] is 10,000 or more and 200,000 or less.
f) The weight average molecular weight [Mw] and the number average molecular weight [Mn] satisfy the relationship of molecular weight distribution [Mw] / [Mn] ≦ 4.
g) The amount of the extract by boiling diethyl ether is 0% by mass or more and 10% by mass or less based on the total solid content of the low crystalline polyolefin resin.

  As the low crystalline polyolefin resin applicable to the second component, commercially available polypropylene having a melting point of 52 ° C. (for the purpose of illustration, not for limitation, for example, a melting point of 52 °, MFR 50 g / 10 min polypropylene) is preferably used. Can do.

  The low crystalline polyolefin resin is difficult to produce crystals because the side chain directions are not uniform, and the fibers and nonwoven fabrics using the low crystalline polyolefin resin tend to be soft, small and soft to the touch.

(Other ingredients)
In each of the first component and the second component, the composite fiber may contain other components as necessary in addition to the thermoplastic resin as long as the object of the present invention is not impaired.

  Examples of other components include various stabilizers such as known heat stabilizers and weather stabilizers, antistatic agents, slip agents, antiblocking agents, antifogging agents, lubricants, dyes, pigments, natural oils, and synthetic oils. And wax.

  Examples of the stabilizer include an anti-aging agent such as 2,6-di-t-butyl-4-methylphenol (BHT); tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxy Phenyl) propionate] methane, β- (3,5-di-t-butyl-4-hydroxyphenyl) propionic acid alkyl ester, 2,2′-oxamide bis [ethyl-3- (3,5-di-t-butyl) Phenolic antioxidants such as -4-hydroxyphenyl) propionate; fatty acid metal salts such as zinc stearate, calcium stearate, calcium 1,2-hydroxystearate; glycerin monostearate, glycerin distearate, pentaerythritol monostearate , Pentaerythritol distearate, pentaerythritol tristearate Polyhydric alcohol fatty acid ester and the like of. Moreover, these can also be used in combination.

  Examples of the lubricant include oleic acid amide, erucic acid amide, stearic acid amide, and the like.

  Also, silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloon, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, A filler such as talc, clay, mica, asbestos, calcium silicate, montmorillonite, bentonite, graphite, aluminum powder, molybdenum sulfide may be contained.

  FIG. 1 is a cross-sectional view showing the configuration of the conjugate fiber according to the present embodiment for the purpose of illustration and not for the purpose of limitation. In the cross section, that is, the cross section perpendicular to the longitudinal direction of the composite fiber, the fiber-forming component is divided into two zones. A first component 1010 is disposed in one zone, and a second component 1020 is disposed in the other zone.

  FIG. 1A shows a core-sheath type composite fiber 1001 having a first component 1010 as a core component and a second component 1020 as a sheath component surrounding the first component 1010. In this figure, an eccentric core-sheath type composite fiber having a core component shifted from the center of the fiber is particularly shown. FIG. 1B shows a side-by-side type composite fiber 1002 in which the first component 1010 and the second component 1020 are close to each other.

  In the conjugate fiber according to the present embodiment, a first component containing a long-chain branched structure polyolefin resin and a second component different from the first component are asymmetric in a cross section perpendicular to the longitudinal direction of the conjugate fiber. Is arranged. Compared with the second component, the first component tends to advance the molecular orientation when it is spun and stretched, and the crystallization is easily promoted. Therefore, the composite fiber according to the present embodiment exhibits high crimpability. Moreover, the nonwoven fabric using this conjugate fiber has good stretchability and cushioning properties, and is bulky.

  In FIG. 1, the composite fiber formed from the two fiber forming components of the first component and the second component is illustrated, but the composite fiber applicable to the present embodiment is not limited to this, and the composite fiber It may be a composite fiber formed from three or more kinds of fiber-forming components including the first component and the second component as long as the material does not interfere with the crimpability of the fiber and the arrangement in the fiber.

  The fineness of the composite fiber according to the present embodiment can be appropriately set depending on the use of the nonwoven fabric, etc., but it is 0.1 denier or more and less than 10 denier, preferably 0.3 denier or more and less than 5 denier, more preferably 0.5 or more and 3 denier. Is less than.

(Fiber properties: crimp)
The degree of crimping of the fiber can be indicated by the number of crimps of the fiber measured in accordance with, for example, Japanese Industrial Standard JIS L1015. The number of crimps of the composite fiber of the present embodiment can be set as appropriate depending on the blending ratio of the components, but is preferably 18 or more per fiber 25 mm, more preferably 20 to 50, and visibility and formation in the resulting nonwoven fabric. From the viewpoint, 20 to 40 is more preferable, and 20 to 30 is most preferable.

<Nonwoven fabric>
The nonwoven fabric by this Embodiment consists of the composite fiber by this Embodiment mentioned above. The nonwoven fabric according to the present embodiment contains the above-described composite fiber in an amount of preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass, based on the total solid content of the nonwoven fabric. It is preferably contained in an amount of 80% by mass or more, and more preferably 90% by mass or more. The nonwoven fabric according to the present embodiment may have a single-layer configuration composed of one layer, or may have a multilayer configuration composed of a plurality of layers. When a nonwoven fabric is a laminated body which has a multilayer structure, it is preferable that a nonwoven fabric contains the above-mentioned composite fiber in the quantity of 60 mass% or more on the basis of the total solid of the whole nonwoven fabric.

(Layer structure)
As described above, the nonwoven fabric according to the present embodiment may have a single-layer configuration composed of one layer, or may have a multilayer configuration composed of a plurality of layers. Each of the plurality of layers of the nonwoven fabric having a multilayer structure according to the present embodiment may be a separately formed nonwoven fabric.

  For example, the nonwoven fabric having a multilayer structure according to the present embodiment has a single-layered nonwoven fabric according to the present embodiment as one layer, and a spunbond made of non-crimped fibers manufactured by, for example, a spunband method. You may have the structure which laminated the nonwoven fabric as a surface layer. At this time, the fineness of the non-crimped fiber is, for example, preferably 0.5 denier or more and less than 2.5 denier, more preferably 0.5 denier or more and less than 1.5 denier. According to this configuration, it is possible to obtain a nonwoven fabric in the form of a laminate that is not only difficult to wrinkle but also has excellent surface smoothness and improved water resistance. In addition, the non-woven fabric according to the present embodiment can be laminated separately to improve the surface properties and to provide functionality to the non-woven fabric according to the present embodiment having a single layer configuration. .

The following are mentioned as a non-limiting example of the structure of the nonwoven fabric of such a laminated body. In the following examples, the spunbonded nonwoven fabric described as “mainly crimped conjugate fiber” is intended to be a single-layered nonwoven fabric according to this embodiment. In addition, a spunband nonwoven fabric having a description “consisting mainly of non-crimped fibers” can be obtained by controlling the production conditions of the spunband method.
(A) A non-woven fabric having a two-layer structure of spun band non-woven fabric (mainly composed of non-crimped fibers) / spun band non-woven fabric (mainly composed of crimped composite fibers).
(B) Spun band nonwoven fabric (mainly composed of non-crimped fibers) / spun band nonwoven fabric (mainly composed of crimped composite fibers) / spun band nonwoven fabric (mainly composed of non-crimped fibers) Non-woven fabric.
(C) A non-woven fabric having a three-layer structure of spunband nonwoven fabric (mainly composed of non-crimped fibers) / spunband nonwoven fabric (mainly composed of crimped composite fibers) / melt blown nonwoven fabric.
(D) Spunband nonwoven fabric (mainly composed of non-crimped fibers) / spunband nonwoven fabric (mainly composed of crimped composite fibers) / melt blown nonwoven fabric / spunband nonwoven fabric (mainly composed of non-crimped fibers) Layered nonwoven fabric.
(E) Spunband nonwoven fabric (mainly non-crimped fiber) / spunband nonwoven fabric (mainly crimped conjugate fiber) / melt blown nonwoven fabric / spunband nonwoven fabric (mainly crimped conjugate fiber) / spanband A non-woven fabric (mainly non-crimped fibers), which has a five-layer structure.

It is preferable that the fabric weight of the nonwoven fabric which comprises each layer laminated | stacked exists in the range of 2.0-25 g / m < ² >. If the basis weight is too large, the nonwoven fabric constituting the layer may inhibit the function of the nonwoven fabric constituting the other layer. If the basis weight is too small, the nonwoven fabric constituting the layer may have a small effect of imparting a function to the multilayer nonwoven fabric according to the present embodiment.

(Manufacturing method and apparatus for composite fiber and nonwoven fabric)
The composite fiber and the nonwoven fabric including the composite fiber according to the present embodiment can be obtained by an ordinary composite melt spinning method and apparatus without using a special apparatus. Of these, the spunbond method having excellent productivity is preferably used.

  FIG. 2 shows a manufacturing apparatus that can be used to manufacture the conjugate fiber and nonwoven fabric according to this embodiment for illustrative purposes, not for limitation purposes. In the production of a composite fiber and a nonwoven fabric, first, a mixture (first component) 1110 of a polypropylene-based resin and a long-chain branched polyolefin resin for forming one zone of the composite fiber, and propylene for forming another zone The system resin and the additive mixture (second component) 1120 are separately melted by the extruders 1130 and 1140 to obtain respective melts. Next, each melt is discharged from a spinneret 1150 having a composite spinning nozzle configured to discharge after forming a desired fiber structure, and a composite in which the first component and the second component are combined. Spins long fibers. The spun composite long fiber is cooled by cooling air 1160, further tensioned by drawing air 1170 to a predetermined fineness, collected as it is on the collecting belt of the collecting conveyor 1180, Deposit to thickness. Next, heat and pressure are applied to the deposited composite long fibers by a hot embossing roll 1190 to melt some fibers and entangle the fibers. Thereby, the nonwoven fabric by this Embodiment can be obtained. This entanglement method is also called a heat embossing method, and an embossed pattern appears on the surface of the nonwoven fabric obtained by this method.

  For the nonwoven fabric according to the present embodiment, in addition to the heat embossing method, a method using a means such as needle punch, water jet, ultrasonic wave, or a method of heat-sealing by hot air through is employed as a method of fiber entanglement treatment. can do. The needle punching means is a method in which a needle is inserted into a nonwoven fabric and entangled. The water jet means is a method in which high-pressure water is jetted onto the fiber assembly and entangled. The ultrasonic means is a method in which some fibers are melted and entangled using ultrasonic waves. Hot air through is a method in which hot air is blown into fibers to melt some fibers and entangle them.

[Average fiber diameter of non-woven fiber (μm)]
Using an electron microscope (S-3500N manufactured by Hitachi, Ltd.), a photograph of the fiber nonwoven fabric at a magnification of 1000 times is taken. Of the fibers constituting the fiber nonwoven fabric, 100 arbitrary fibers are selected, and the width (diameter) of the selected fiber is measured. Let the average of a measurement result be an average fiber diameter.

[Porosity of non-woven fabric (%)]
About the arbitrary location of a nonwoven fabric, based on JIS1096, thickness is measured under 0.7 kPa for 10 seconds using a thickness measuring device. From the result, the basis weight of the nonwoven fabric, and the raw material density used for the nonwoven fabric, the porosity is obtained by rounding off the first decimal place of the numerical value obtained by the following formula. However, when the obtained non-woven fabric is a laminate, a single-layer non-woven fabric obtained by removing a spunbonded non-woven fabric mainly composed of non-crimped fibers is measured.

Porosity (%) = [1- (Weight / Thickness / Density)] × 100
In the nonwoven fabric according to the present embodiment, the porosity of the nonwoven fabric is 90% or more, preferably 95% or more. If it is less than 90%, the stretchability to prevent wrinkles is insufficient.

[Bulkness of nonwoven fabric]
A nonwoven fabric sample is cut into a 20 cm square shape, and a set of 8 sheets is taken as one sample, and measured with a compression tester (KES-FB3-AUTO-A, manufactured by Kato Tech Co., Ltd.) under the following setting conditions. . One sample is measured with three measurement points, and an average value of the three points is obtained.

In the nonwoven fabric of the present embodiment, bulk is at 20 cm ³ / g or more, if it is 30 cm ³ / g or more preferred. Moreover, bulkiness is 50 cm < ³ > / g or less, and it is preferable in it being 45 cm < ³ > / g or less. When it is less than 20 cm ³ / g, cushioning properties are insufficient. When it exceeds 50 cm ³ / g, the strength is lowered and the processability is inferior.

(Function and effect)
The composite fiber according to the present embodiment includes a first component and a second component. The first component contains a long-chain branched structure polyolefin resin, and can provide high crimpability to the composite fiber blended therewith. Moreover, bulkiness can be provided with respect to the nonwoven fabric by this Embodiment which has this composite fiber as a main body.

(Use of composite fiber and non-woven fabric)
Below, the use of the composite fiber and nonwoven fabric by this Embodiment is illustrated.

  Nonwoven fabrics according to the present embodiment can be used for (1) clothing, (2) medical, (3) building materials, (4) hygiene, (5) furniture / interior, (6) bedding, ( 7) For industrial materials.

  (1) Examples of clothing include clothing members, disposable clothing (also referred to as disposable clothing), shoes, emblems, gloves, slippers, and hats. Specific examples of the clothing member include interlining, adhesive interlining, filling cotton, bra pad, shoulder pad, jumper liner, and the like. Specific examples of the disposable clothing include event jumpers and travel underwear. Specific examples of the shoe include an insole material and a fishing leather sole.

  (2) Examples of medical use include gauze, surgical gown, covering cloth set, bat for birth, cap, mask, sheets, antibacterial mat, poultice base cloth, poultice base cloth, cast material, and the like. .

  (3) For building materials, for example, roofing, tufts, carpet base fabrics, anti-condensation sheets, temperature control sheets, humidity control sheets, wall coverings, heat insulating materials, moisture absorption materials, soundproof materials, sound absorption materials, vibration isolation materials, Wood materials, curing sheets, etc. are listed.

  (4) Examples of hygiene include diapers, sanitary products, first aid products, cleaning products, towels, masks, and the like. Specific examples of the diaper include a paper diaper and a diaper cover. A specific example of the sanitary product is a napkin. Specific examples of the emergency supplies include gauze, first-aid plasters, and swabs. Specific examples of the cleansing products include breast milk pads, wiping sheets, sweat absorption sheets (for face, side, neck, feet, etc.), antibacterial / antibacterial sheets, antiviral sheets, antiallergen sheets, antibacterial deodorants There are sheets. Specific examples of the mask include a disposable three-dimensional mask.

  (5) Examples of furniture / interior use include carpets, flooring, curtains, furniture parts, joinery, wallpaper, and ornaments. Specific examples of the carpet include carpets, carpet base fabrics, tile carpets, electric carpets, mat base fabrics, and under carpets. Specific examples of the furniture parts include a cushion material and a filling cotton in a reception chair. Specific examples of the joinery include shoji paper, folds, tatami mats, blinds, and the like. Specific examples of the ornament include a pennant, a roll screen, and artificial flowers.

  (6) Examples of bedding include futons, pillow covers, and sheets. Specific examples of the futon include futon batting and futon bags.

  (7) Examples of industrial materials include industrial materials, electrical materials, batteries, product materials, OA equipment, AV equipment, rolls, musical instruments, packaging materials, and the like. Specific examples of the industrial material include an abrasive, an oil absorbing material, a papermaking felt, a heat resistant cushion, a draining material, a heat insulating material, a soundproofing material, and a vibration proofing material. Specific examples of the electrical material include an electrical insulating material, a printed circuit board base material, an electromagnetic wave shielding material, a static electricity removal sheet, and a wire holding tape. Specific examples of the battery include a separator. Specific examples of the product material include FRP (fiber reinforced plastic) base material, tape, printing base fabric, synthetic paper, electrostatic recording paper, adhesive tape, thermal transfer sheet, radiation shielding mat, and the like. Specific examples of the OA device include a disk liner and a packaging material. Specific examples of the AV device include a speaker diaphragm and a sound absorbing plate. Specific examples of the roll include a buffalo, a coating roll, and a squeezed roll. Specific examples of the musical instrument include a piano key cushion and a hammer rail. Specific examples of the packaging material include dry ice packaging material and packing.

  Moreover, it is not limited to the said classification | category, The composite fiber and nonwoven fabric by this Embodiment can be used in the field | area and the application which are various. The nonwoven fabric by this Embodiment can be used conveniently for an absorbent article, especially the top sheet | seat of an absorbent article, the wrap sheet | seat of a core wrap type absorber, etc. When the nonwoven fabric according to the present embodiment is used for an absorbent article, cushioning properties are high, bumps due to wrinkles are not easily generated, and a good touch and a good wearing feeling can be provided.

<Absorbent article>
In the present specification, the “absorbent article” refers to an article having a property (absorbability) for taking in body fluids such as urine, blood, sweat, and breast milk, and liquids such as water and moisture. Examples of absorbent articles include diapers, sanitary products, sweat-absorbing sheets (for face, side, neck, feet, etc.), breast pads, anti-condensation sheets, humidity control sheets, hygroscopic materials, for illustrative purposes and not for limited purposes. Articles such as wiping sheets, joinery, wallpaper, cushions, bedding are included. The absorbent article according to the present embodiment can be preferably used particularly for diapers for infants, diapers for adults, urine leak pads, diapers for pets, pet toilet mats, and the like. Accordingly, the absorbent article is an absorbent article (final product) and also includes an absorbent article as an intermediate.

<Embodiment>
The absorbent article using the composite fiber according to the present embodiment will be described using an example of a pants-type disposable diaper shown in FIG. FIG. 7 is a three-dimensional projection view showing the appearance of a pants-type disposable diaper using the absorbent article according to the present embodiment. FIG. 8 is a three-dimensional projection view of the lower body wearing the diaper shown in FIG. 7 as seen from the back side. FIG. 9 is a three-dimensional projection view showing the diaper shown in FIG. 7 in an exploded state. FIG. 10 is a top view of the diaper absorbent body shown in FIG. 7 as viewed from the front side of the top sheet. 11 is a cross-sectional view showing a central portion of the diaper shown in FIG. 7 cut along the line XI-XI.

  A pants-type disposable diaper (hereinafter also simply referred to as a diaper) 10 according to the present embodiment has a front body region 10F, a back body region 10R, and a crotch region 10C that connects the front body region 10F and the back body region 10R. . Moreover, the waist periphery opening part 10W which surrounds a wearer's waist part with the front body area | region 10F and the back body area | region 10R at the time of wear is formed. Similarly, a pair of left and right leg openings 10L that surround the thigh portions of both legs of the wearer are formed by the lower end crotch region 10C of the front body region 10F and the back body region 10R.

  As shown in FIG. 8, when worn, the front body region 10F is located on the wearer's belly side, and the back body region 10R is located on the wearer's back side. The crotch region 10 </ b> C covers the wearer's crotch, and the leg of the wearer is passed through the pair of left and right leg openings 10 </ b> L. Therefore, the leg periphery opening 10L is located at any position around the thigh from the base of the wearer's legs.

  A disposal tape 10T is provided in the back body region 10R of the diaper to be rounded and stopped when the diaper is discarded.

  The imaginary line P extends through the crotch part from the abdomen side to the back side in the central part of the diaper. Specifically, the imaginary line P extends, for example, along the diaper surface and in the vertical direction when the waist side of the diaper is up and the crotch side is down. It extends in the vertical direction. In other words, the vertical direction is a direction along the center axis of the body from the wearer's head to the crotch, and the virtual line P extends along the center axis of the body.

  As shown in FIGS. 9 to 11, the diaper 10 using the absorbent article according to the present embodiment has a cover sheet 11, a back sheet 12, an absorber 13, and a top that touches the wearer's skin in order from the outside. The sheets 14 are sequentially stacked and joined. The left and right side edges of the cover sheet 11 that define the front body region 10F and the back body region 10R of the diaper 10 together with the crotch region 10C are joined together to form a closing portion 10J. As a result, a waist opening 10W and a pair of left and right leg openings 10L surrounding the thighs of both legs are defined, and the leg openings 10L are respectively provided on the left and right sides of the crotch region 10C of the cover sheet 11. A pair of cutout portions 11A having a semicircular arc shape is formed. The liquid-impermeable back sheet 12 is joined to the inner cover sheet 11 </ b> B, and the absorber 13 is disposed between the back sheet 12 and the liquid-permeable top sheet 14, and the top sheet 14 is interposed via the absorber 13. Is bonded to the backsheet 12. Between the outer cover sheet 11C and the inner cover sheet 11B, which are formed of a thin non-woven fabric in order to obtain a good touch, the rubber thread 15 for forming the leg gathers and the waist gathers are formed. The rubber thread 17 is joined in an extended state.

<Absorber>
In the present specification, the “absorber” includes, for example, a body fluid such as urine, blood, sweat, and breast milk, and a material having a property (absorbability) for taking in water, moisture, and the like. Say what you indicate. As an example of an absorptive material, a pulp, rayon, a superabsorbent polymer, etc. are mentioned, for example.

  As the absorber 13 of the present embodiment, any absorber known in the field of absorbent articles can be used. A combination of cotton-like pulp and a superabsorbent polymer can be preferably used.

<Cotton pulp>
As the cotton-like pulp, for example, a fiber sheet having a fiber length of 5 mm or less can be suitably used by defibrating a pulp sheet with a pulverizer. The pulp sheet used at this time may be a chemical pulp sheet or a mechanical pulp sheet, and the pulp raw material is not particularly limited as long as it is used as a normal pulp raw material, such as softwood, hardwood, straw, bamboo, kenaf, waste paper, etc. Can be used. The amount of cotton-like pulp used varies depending on the application and the structure of the absorbent body, but is generally 50 to 400 g / m ² .

<Superabsorbent polymer>
As a super absorbent polymer (hereinafter also referred to as SAP), starch-based, cellulose-based, and synthetic resin-based SAPs are known, and any one of these may be used alone or in combination. It may also be used by containing other substances. Specifically, starch-acrylic acid (salt) graft copolymer, saponified starch-ethyl acrylate graft copolymer, saponified starch-methyl methacrylate graft copolymer, starch-acrylonitrile graft copolymer Saponified product of starch, acrylamide saponified graft copolymer, polyacrylic acid (salt), polyethylene oxide crosslinked with acrylic acid, crosslinked product of sodium carboxymethyl cellulose, crosslinked product of polyvinyl alcohol-maleic anhydride Can be used. Among them, sodium polyacrylate having a high absorption performance capable of absorbing water 20 times or more of its own weight is preferably used.

  There is no limitation on the shape of the SAP, and particles, fibers, sheets, and the like can be used. When used for absorbent articles such as sanitary products that touch the user's skin, it is preferable that the user does not feel the presence or shape of the SAP, and particulate SAP can be preferably used. The particle size of the particulate SAP is, for example, 1000 μm or less, and preferably, for example, 400 μm or less. Moreover, since it will be easy to leak from an absorber when a particle size is too small, it is preferable that the particle size of SAP is 150 micrometers or more, for example.

<Configuration of absorber>
In the absorber 13 of the present embodiment, the absorbent material is usually used in a single-layer or multi-layer mat shape. As for an absorptive material, 1 type may be used independently and 2 or more types may be used together.

  Especially, what used particulate SAP together with cotton-like pulp is preferable. The SAP may be uniformly mixed in a cotton-like pulp mat, or may be arranged in layers between layers of a multi-layered cotton-like pulp.

  The amount of SAP is preferably 10 to 500 parts by mass and more preferably 15 to 300 parts by mass with respect to 100 parts by mass of the dried cotton-like pulp. By setting such an amount, mutual interference between SAP particles is stopped. For this reason, SAP particles that have absorbed and gelled liquid rarely form a permeation barrier against the liquid to be absorbed, and urine and body fluid can permeate in the absorbent body in a three-dimensional direction and be absorbed.

  In general, when the amount of liquid to be absorbed in the absorber is large, a phenomenon that the liquid that could not be absorbed leaks (so-called liquid leakage) may occur. By mix | blending SAP with the absorber 13, the liquid absorbable amount can be increased, without increasing the pulp amount. Therefore, it is possible to realize an absorbent body having a good absorbability that is less likely to cause liquid leakage while being thin.

  As the absorbent body 13 of the present embodiment, an absorbent material in which the absorbent material is held by a hydrophilic sheet can be used. For example, a hydrophilic sheet provided with a hydrophilic layer on the surface of an absorbent material such as a SAP sheet provided on one side and a SAP sheet sandwiched between two hydrophilic sheets can do. In particular, the so-called “core wrap type absorber”, in which the water-absorbing material is the core and the whole is wrapped with the core wrap of a hydrophilic sheet like tissue, prevents the water-absorbing material that is the core from being exposed or leaked. ,preferable.

Examples of the hydrophilic sheet include tissue, absorbent paper, and non-woven fabric subjected to hydrophilic treatment. Those having a basis weight in the range of 5 to 40 g / m ² , particularly those having a basis weight in the range of 10 to 30 g / m ² can be suitably used. It is preferable to use a crimped nonwoven fabric as the hydrophilic sheet. According to this, when an absorber receives external force, such as squeezing, a hydrophilic sheet | seat is torn and possibility that absorbent materials, such as SAP currently hold | maintained, will be exposed or leaked will be reduced. Moreover, if a crimped nonwoven fabric is used, it becomes bulky and can improve cushioning properties, and it is possible to reduce the problem of skin irritation caused by contact with a hard part that is comfortable to the touch / skin. Details of the crimped nonwoven fabric will be described later.

<Shape and size of absorber>
Any size and shape of the absorber can be used depending on the application. For example, the absorber may have an hourglass shape in a plan view, and may be a rectangle, an ellipse, a semicircle, or the like. The hourglass shape is preferable because it easily fits the user's body when the absorbent body is applied to a sanitary product.

  In the absorbent article according to the present embodiment, at least a part of the absorbent body is covered with a sheet. The sheet only needs to be positioned so that the sheet covers at least a part of the absorbent body when the sheet and the absorbent body are viewed from the front side of the sheet. The sheet area may be larger than the absorber area. Moreover, the sheet | seat and the absorber do not necessarily need to contact directly. The sheet may cover the entirety of the absorber, i.e., it may wrap around the absorber. When the absorbent body has a shape having a relatively large area front and back surfaces and side surfaces surrounding the front and back surfaces, such as a sheet shape, a flat plate shape, or a mat shape, the sheet is formed on the front and back surfaces of the absorber. It is preferable to arrange on at least one surface. At this time, the sheet may entirely cover or partially cover at least one surface. The sheet | seat may be arrange | positioned at both the front and back of an absorber, and may be arrange | positioned further at the side surface. One sheet may be arranged, or a plurality of sheets may be laminated. When laminated, the plurality of sheets may or may not be bonded to each other. The sheet may be composed of a single sheet or a plurality of sheets in the planar direction. In the case of a plurality of sheets, the plurality of sheets may or may not be joined to each other.

  As shown in FIG. 10 and FIG. 11, the top sheet 14 covers the entire upper surface of the absorbent body 13, and both are integrated by a hot melt adhesive to form the absorbent article of the present embodiment. ing. The top sheet 14 and the absorber 13 are provided with a groove-like recess 21 (hereinafter also referred to as a groove 21 or a recess 21) that extends in an oblique lattice shape. As shown in FIG. 11, the groove 21 is recessed from the top sheet 14 side toward the absorber 13 side. The groove 21 has a function as a passage for guiding urine, a function of reducing the humidity in the diaper by circulating air inside and outside the diaper, and when the absorber 13 absorbs urine, the wearer side (cross-sectional view of FIG. 11). In the above, a function of relaxing the pressure on the wearer by inflating only on the upper side in the vertical direction defined by the direction of the written code is provided.

  As shown in FIG. 10, the groove 21 is inclined in one specific direction with respect to an imaginary line P that is assumed to extend along the central axis of the diaper wearer's body on the upper surface of the top sheet 14. The plurality of first grooves 21a extending in the direction and the plurality of second grooves 21b extending in a direction different from the first groove 21a. That is, with the imaginary line P as an axis, the first groove 21a is inclined at an angle α on one side, and the second groove 21b is inclined at an angle β on the other side. The angle α and the angle β may be the same or different.

  In FIG. 10, the plurality of first grooves 21a are inclined at the same angle, and are arranged at regular intervals. That is, although each 1st groove | channel 21a is arrange | positioned in parallel and fixed space | interval, this Embodiment is not restricted to this, The thing where the space | interval of a groove | channel is not constant and the inclination angle of each groove | channel differs. The same applies to the second groove 21b.

  In FIG. 10, a plurality of first grooves 21a and second grooves 21b are formed, but this embodiment is not limited to this, and grooves extending in an oblique direction are formed one by one on the left and right. It may be what you have. Although it is preferable that the two intersect, this embodiment is not limited to this, and includes those in which the two do not intersect directly and the extending directions of the grooves intersect. Furthermore, a configuration in which all the grooves are oriented in the same direction (parallel) such as 21a and 21b may be employed, or a configuration having only one groove (only one) may be employed. Of course, it may be a groove provided with a curved portion, and may be constituted by two or more kinds of grooves. These groove patterns can be appropriately designed in consideration of performance for guiding urine from the urination position, air permeability, and contact properties with the skin (per skin / feel, etc.).

  The groove | channel 21 is a member in which the predetermined groove pattern was formed from the upper surface of the top sheet 14, and is formed by pressing together the top sheet 14 and the absorber 13 from the top sheet 14 side. That is, in this embodiment, as shown in FIG. 11, the absorbent body 13 has a recess formed on the top sheet 14 side and no recess formed on the back sheet 12 side. The width and depth of each groove 21 may be uniform, or may vary depending on the distance between adjacent grooves, the position of the groove, and the like. Further, the side wall of the groove 21 may extend substantially perpendicularly from the absorber surface as shown in FIG. 12, or may have a V-shape inclined obliquely as shown in FIG.

  By the squeezing for forming the groove 21, the groove 21 part of the absorbent body 13 is compressed as compared with other parts, and the density of the absorbent body 13 is increased. The porosity of the pressed portion is, for example, 20% or less, preferably 5% or less. Moreover, the absorber density of the squeezed part is set to be twice or more as compared with the non-squeezed part. The absorber density is mainly the density of the pulp.

  In the present embodiment, if the direction opposite to the direction indicated by the phantom line P is the width direction, the absorber 13 has a groove forming region N1 at the center in the width direction, and groove non-forming regions N2 on both sides thereof. have. In FIG. 10, both end portions in the width direction of the absorber 13 are non-grooved regions N2, and the groove forming region N1 extends in a band shape from one end to the other end in the direction indicated by the phantom line P in the center. . As described above, the groove 21 portion of the absorbent body 13 is formed by pressing the absorbent body 13. Therefore, in the groove 21 portion, the absorber 13 is compressed and harder than the other portions of the absorber 13. By not providing the grooves 21 at both ends in the width direction of the absorbent body where the inner crotch of the leg contacts, the texture is improved and the wearing feeling is improved. However, it goes without saying that the groove 21 may also be provided at the end in the width direction depending on the position and size of the absorber. That is, it can be appropriately modified to a configuration in which the non-groove formation region N2 is not provided, or a configuration in which the non-groove formation region is provided in the central portion in the width direction of the diaper (left-right direction in FIG. 10).

  By the way, people walk with their legs alternately forward and left. As for high and high, the movement of the base of the crotch is the same as when walking, and it is put forward alternately. Since the diaper in the vicinity of the leg that is put forward is pulled in the forward direction, the crotch portion of the diaper is pulled in an oblique direction. That is, when the right foot comes forward, the diaper is pulled in an oblique direction from the lower left of the crotch to the upper right. On the other hand, when the left foot comes forward, the diaper is pulled in an oblique direction from the lower right of the crotch to the upper left. The diaper of the present embodiment has rigidity against the tensile force in the oblique direction due to walking because the oblique groove 21 is formed in the absorber 13. Since the crotch portion M2 of the absorbent body 13, that is, the large and slanted groove 21 extends in the center portion, the first groove 21a and the second groove 21b alternate with respect to the pulling force due to the back and forth movement of both feet. Exhibits rigidity and prevents the absorber 13 from being twisted or deformed.

  Since the outer periphery of the absorber in the suppressing portion 22 is pressed by the groove 21, the shape loss suppressing portion 22 is difficult to deform. Therefore, even if a tensile force is generated in the oblique direction, the absorber 13 is more difficult to be wrinkled obliquely due to the rigidity of the groove 21 and the deformation preventing portion 22 is difficult to deform. As a result, deformation in the oblique direction is suppressed. Will be. Therefore, the absorber 13 is not greatly deformed and deformed by the longitudinal movement of the legs. Since the absorbent body 13 does not move, the fit between the crotch can be maintained, and body fluid leakage hardly occurs. Moreover, since it can also suppress that the absorber 13 cuts by deformation | transformation, absorption performance can be maintained.

  In order to suppress the deformation of the absorber 13 due to the movement of the legs, a preferable arrangement of the grooves 21 is as follows. That is, the inclination angle of the groove 21 with respect to the longitudinal direction is 10 degrees or more and less than 80 degrees, and preferably 45 degrees or more and 60 degrees or less. And it is better for the groove | channel 21 to incline symmetrically. Moreover, the groove | channel inclined in the same direction, ie, the space | interval of the some 1st groove | channel 21a, and the space | interval of the some 2nd groove | channel 21b are 10 mm or more and less than 100 mm, and 10 mm or more and 30 mm or less are especially preferable.

  In the present embodiment, the groove forming region N1 extends from the front body portion M1 to the back body portion M3 of the absorber 13, but the present invention is not limited to this. That is, the groove forming region N1 may be formed only in the crotch portion M2. Moreover, even if it is formed in the front body part M1 and the back body part M3, a longitudinal direction edge part may not be formed. Since the portion close to the waist portion is brought into close contact with the skin by waist gathers, the feeling of wearing is improved by preventing the hard portion of the groove 21 from contacting the skin.

  The liquid-impermeable side sheets 18 are joined to the left and right side edges of the liquid-permeable top sheet 14 in the present embodiment, and three-dimensional gathers are formed at the inner edge of the left and right side sheets 18. Thread rubber 19 is joined in an extended state

(Modification)
12 and 13 show another configuration example of the absorbent article according to the present embodiment.

  As shown in FIG. 12, in this example, the upper and lower surfaces of the absorber 13 are covered with a sheet 13 </ b> B (core wrap sheet). In this example, the sheet 13 </ b> B that covers the upper and lower surfaces is connected at a place not shown. That is, in this example, the sheet 13B wraps around the absorber 13, and forms a single core wrap type absorber by taking the relationship between the so-called core wrap sheet and the absorber core. However, the present embodiment is not limited to this, and the upper and lower surfaces 13B may be separate sheets. Further, the sheet 13B may cover only a part of the absorber 13, and in this case, the sheet 13B is configured to cover at least one groove portion 21. As for the some sheet | seat which covers the groove part 21, at least 1 is comprised with a crimped nonwoven fabric. “Constituted of crimped nonwoven fabric” includes not only the configuration of the crimped nonwoven fabric in the region but also the configuration in which one of the regions is a crimped nonwoven fabric in a multi-layer structure, for example. The absorber 13 and the sheet 13B are integrally joined. The sheet 13B on the surface (upper surface) of the absorbent body 13 on the top sheet 14 side, together with the absorbent body 13, forms a recess 21 that is recessed from the upper surface sheet 13B side toward the absorbent body 13 side. Thus, in the example of this Embodiment shown in FIG. 12, the absorber 13 and the sheet | seat 13B which covers it comprise the absorbent article. The absorbent article can be used between a top sheet 14 and a back sheet 12 and bonded to the diaper.

  In the example shown in FIG. 13, the surface (upper surface) on the top sheet 14 side of the sheet 13 </ b> B of the core wrap type absorber described in FIG. 12 is covered with the top sheet 14, and the top sheet 14 and the top of the absorber 13 are covered. A sheet 13 </ b> B on the sheet 14 side surface (upper surface, that is, a liquid absorption surface), together with the absorber 13, forms a recess 21 that is recessed from the top sheet 14 side toward the absorber 13 side. In this example, the absorbent body 13 and the sheet 13B and the top sheet 14 covering the absorbent body 13 constitute an absorbent article. This absorbent article can be used alone, or can be used on a diaper or the like after being disposed on and joined to the back sheet 12.

  Or what joined this top sheet 14, sheet 13B, and absorber 13 with back sheet 12 can also be used as an absorptive article by this embodiment.

The absorbent article by this Embodiment is comprised including the nonwoven fabric containing the composite fiber by this Embodiment. For example, for the purpose of illustration rather than limitation, the absorbent article according to the present embodiment can have the following layer configuration.
(1) Absorber (2) Top sheet / Absorber (3) Absorber / Back sheet (4) Top sheet / Absorber / Back sheet (5) Top sheet / Reverse prevention sheet / Absorber (6) Absorber / Back-through prevention sheet / back sheet (7) Top sheet / reverse prevention sheet / absorber / back sheet (8) Top sheet / absorber / back-through prevention sheet / back sheet (9) Top sheet / reverse prevention sheet / absorber / Back-through prevention sheet / Back sheet (10) Core wrap type absorber The “absorber” in the above layer configuration example is an absorbent core (hereinafter also referred to as “absorber core”) and a sheet (hereinafter referred to as “absorber core”). , “Core wrap sheet” or simply “core wrap”). In the case of the core wrap type absorbent body, since it includes the absorbent body and a sheet (core wrap sheet) that covers at least a part, the configuration not including other sheets as shown in (10) This is an absorbent article according to the present embodiment.

  The nonwoven fabric by this Embodiment can be used as sheets, such as a top sheet of an absorbent article, a core wrap sheet, a back sheet, a backlash prevention sheet, and a back-through prevention sheet. Moreover, the structure which provided the cover sheet further in the outermost layer with respect to the structure of (1) to (10) is also an absorptive article by this Embodiment, and uses the nonwoven fabric by this Embodiment as a cover sheet. You can also

  By using the nonwoven fabric of the present embodiment for the sheet constituting the absorbent article, an absorbent article that is imparted with cushioning properties and hardly wrinkles, has a good feel and excellent wearing feeling can be obtained. When the nonwoven fabric of this Embodiment is used for a topcoat, a core wrap sheet | seat, and a back sheet | seat especially, this effect becomes remarkable and is preferable.

<Recess>
The absorbent article according to the present embodiment shown in FIGS. 10 to 14 has a concave portion 21 that is recessed from the sheet side (including the core wrap sheet) toward the absorbent core side. It is the pressing recessed part provided by pressing from the sheet | seat side. The recess can be provided by any pressing means known in the field of absorbent articles, such as an embossing method and an embossing device. Specifically, for example, for a laminate including an absorbent body and a sheet constituting an absorbent article, an embossing roll having unevenness on the surface is brought into contact with the sheet side and rotated while applying pressure, thereby the sheet and A concave part can be formed in the sheet | seat side by pressing together with an absorber.

  The shape of the recess is not limited, and the recess may be, for example, a dot formed by an emboss pattern such as a dot, a line formed by connecting dots, or a groove. May be. The point may be a circle (including a true circle or an ellipse), a polygon (such as a triangle or a quadrangle), or a character type.

  In the above configuration example, the concave portion is provided on the liquid absorption surface (skin contact surface) side. However, depending on the purpose and effect, the concave portion can be provided on the non-liquid absorption surface side. For example, there may be a purpose such as aesthetic appearance such as designability or imparting rigidity by improving density.

  In the absorbent article according to this embodiment, the sheet that forms a recess that is recessed from the sheet side toward the absorber side is a sheet that is formed of a crimped nonwoven fabric.

(Function and effect)
In the absorbent article according to the present embodiment, the nonwoven fabric according to the present embodiment can be used for at least one of the sheets constituting the above-described layers. In particular, when the nonwoven fabric of the present embodiment is used for an outer layer such as a top sheet or a back sheet layer, it is difficult to cause wrinkles, and thus it is possible to provide an excellent wearing feeling that is unlikely to cause discomfort to the user. be able to.

  If this nonwoven fabric is used for a sheet existing on the surface side such as a top sheet, unevenness due to wrinkles is unlikely to occur, and a good touch can be provided. In particular, when the compressed groove is provided from the top sheet side, the absorbent body is compressed and hardened in the groove portion. However, by providing the nonwoven fabric on the top sheet, this hardness can be reduced. This function can be obtained, and the problem can be solved. Especially where the groove-shaped compressed grooves intersect, the absorber becomes hard, but if a top sheet using this nonwoven fabric is adopted, the risk of relaxing the hardness at such places and pressing the skin It is also possible to prevent sex. Therefore, it is preferable to use the nonwoven fabric on the entire surface of the sheet, but even if the nonwoven fabric is used at least at the location where the compressed groove is provided or at the intersection of the compressed groove, a sufficient effect can be obtained. The same applies when the pressing groove is provided from the back sheet side.

  If this non-woven fabric is used for the inner sheet of the top sheet, for example, core wrap, bumps due to poetry are less likely to occur, reducing the possibility of causing irregularities on the surface side (top sheet side, back sheet side, etc.). . In particular, when a compression groove is provided for the absorbent body, if the absorbent body that has been bumpy is squeezed without using this nonwoven fabric, the core wrap will be broken at the bumpy portion, and the contents will leak to the outside. There is a risk that On the other hand, if this nonwoven fabric is used, the possibility of occurrence of such bumps (wrinkles) can be reduced, so that it is possible to prevent the bumps from being broken during pressing. That is, if the nonwoven fabric is provided on at least a portion where the compressed groove is provided, and further on the nonwoven fabric of the sheet located at the intersection portion of the groove as described above, the absorber breakage can be effectively prevented. Naturally, the influence of wrinkles is not transmitted to the surface side, and the touch is improved.

  In addition, if one or a plurality of sheets (especially the sheet on the side where the compressed grooves are provided) are provided with stretchability by imparting crimpability as described above, the sheets will be extended when the compressed grooves are provided. It is also possible to prevent sheet tearing during groove formation. Furthermore, it is possible to prevent the sheet from being torn by an external load after forming the groove.

(Method for manufacturing absorbent article)
The absorbent article (diaper 10) of this Embodiment is manufactured by the manufacturing method including the following processes, for example.
(1) An absorbent body (absorber core) 13 composed of pulp and SAP is wrapped with a core wrap 13B, which is a liquid-permeable sheet, to produce a continuous mat-shaped core wrap type absorbent body.
(2) The continuous mat-shaped core wrap type absorber is narrowed through the nip while rotating a pair of embossing rolls having a convex embossing pattern on the surface, and embossed. By this embossing, a recess 21 corresponding to the shape of the emboss pattern is formed on the surface of the continuous absorber 13.
(3) The continuous mat-shaped core wrap type absorbent body after embossing is cut into a length required for one diaper by a cutting device, and a liquid-permeable top sheet 14 and a liquid-impermeable back sheet 12 are obtained. Then, it is joined to the cover sheet 11 having a soft touch and processed into a diaper shape. Thereby, the diaper 10 is manufactured.

  In said manufacturing method, although the recessed part 21 is formed by squeezing an absorber core and a core wrap, embodiment of this invention is not restricted to this. For example, you may form the recessed part 21 by pressing what laminated | stacked the absorber core and the core wrap, and the top sheet. Moreover, when pressing what laminated | stacked the absorber 13 and the top sheet | seat 14, the absorber 13 and the top sheet | seat 14 which were previously divided into the predetermined dimension (for example, cut | disconnected) are joined, and it squeezes with respect to this May be applied. In addition, appropriate changes and modifications are possible.

(Use of absorbent articles)
Below, the use of the absorbent article by this Embodiment is illustrated.

  Applications of the absorbent article according to the present embodiment include (1) for clothing, (2) for medical use, (3) for building materials, (4) for hygiene, (5) for furniture and interior, and (6) for bedding (7) For industrial materials.

  (1) Examples of clothing include clothing members, disposable clothing (also referred to as disposable clothing), shoes, emblems, gloves, slippers, and hats. Specific examples of the clothing member include interlining, adhesive interlining, filling cotton, bra pad, shoulder pad, jumper liner, and the like. Specific examples of the disposable clothing include event jumpers and travel underwear. Specific examples of the shoe include an insole material and a fishing leather sole.

  (2) For medical use, for example, gauze, surgical clothes, covering cloth set, bat for birth, cap, mask, sheets, antibacterial mat, poultice base cloth, poultice base cloth, cast material, artificial skin, etc. Can be mentioned.

  (3) For building materials, for example, roofing, tufts, carpet base fabrics, anti-condensation sheets, temperature control sheets, humidity control sheets, wall coverings, heat insulating materials, moisture absorption materials, soundproof materials, sound absorption materials, vibration isolation materials, Wood materials, curing sheets, etc. are listed.

  (4) Examples of hygiene include diapers, sanitary products, first aid products, cleaning products, towels, masks, and the like. Specific examples of the diaper include a paper diaper and a diaper cover. A specific example of the sanitary product is a napkin. Specific examples of the emergency supplies include gauze, first-aid plasters, and swabs. Specific examples of the cleansing products include breast milk pads, wiping sheets, sweat absorption sheets (for face, side, neck, feet, etc.), antibacterial / antibacterial sheets, antiviral sheets, antiallergen sheets, antibacterial deodorants There are sheets. Specific examples of the mask include a disposable three-dimensional mask.

  (5) Examples of furniture / interior use include carpets, flooring, curtains, furniture parts, joinery, wallpaper, and ornaments. Specific examples of the carpet include carpets, carpet base fabrics, tile carpets, electric carpets, mat base fabrics, and under carpets. Specific examples of the furniture parts include a cushion material and a filling cotton in a reception chair. Specific examples of the joinery include shoji paper, folds, tatami mats, blinds, and the like. Specific examples of the ornament include a pennant, a roll screen, and artificial flowers.

  (6) Examples of bedding include futons, pillow covers, and sheets. Specific examples of the futon include futon batting and futon bags.

  (7) Examples of industrial materials include industrial materials, electrical materials, batteries, product materials, OA equipment, AV equipment, rolls, musical instruments, packaging materials, and the like. Specific examples of the industrial material include an abrasive, an oil absorbing material, a papermaking felt, a heat resistant cushion, a draining material, a heat insulating material, a soundproofing material, and a vibration proofing material. Specific examples of the electrical material include an electrical insulating material, a printed circuit board base material, an electromagnetic wave shielding material, a static electricity removal sheet, and a wire holding tape. Specific examples of the battery include a separator. Specific examples of the product material include FRP (fiber reinforced plastic) base material, tape, printing base fabric, synthetic paper, electrostatic recording paper, adhesive tape, thermal transfer sheet, radiation shielding mat, and the like. Specific examples of the OA device include a disk liner and a packaging material. Specific examples of the AV device include a speaker diaphragm and a sound absorbing plate. Specific examples of the roll include a buffalo, a coating roll, and a squeezed roll. Specific examples of the musical instrument include a piano key cushion and a hammer rail. Specific examples of the packaging material include dry ice packaging material and packing.

  Moreover, it is not limited to the said classification | category, The absorptive article using the composite fiber by this Embodiment can be used in various field | areas and uses. The absorbent article using the composite fiber according to the present embodiment can be suitably used particularly for the absorbent composite.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to a following example. The configurations of Examples and Comparative Examples are shown in Tables 1 to 4 in FIGS.

[Example 1]
<Manufacture of composite fiber and nonwoven fabric>
As a first component, polypropylene resin PP (melting point: 162 ° C., MFR: 40 g / 10 minutes) and long-chain branched polypropylene resin PP1 (melting point: 162 ° C., MFR: 8 g / 10 minutes) are 99% by mass in terms of solid content: 1 A mixture mixed at a blending ratio of mass% was prepared. As the second component, polypropylene resin PP (melting point 162 ° C., MFR 40 g / 10 min), low crystalline polyolefin resin PP (melting point 52 ° C., MFR 50 g / 10 min), and organic additive (erucamide 5 % PP masterbatch (based on polypropylene resin and containing 5% by mass of active ingredient erucamide) and inorganic pigment (50% titanium oxide PP masterbatch (based on polypropylene resin and containing active ingredient titanium oxide) In the amount of 50% by mass) and a mixture ratio of 74% by mass: 20% by mass: 4% by mass: 2% by mass in terms of solid content.

  Using the apparatus shown in FIG. 2, spinning of the conjugate fiber and production of the nonwoven fabric were performed. Specifically, first, the first component and the second component were separately melted by the extruders 130 and 140, respectively, to obtain respective melts. Next, each melt is discharged from a spinneret 150 having a composite spinning nozzle configured to form and discharge an eccentric core-sheath type composite fiber structure, and the first component and the second component are discharged. An eccentric core-sheath type composite fiber that was compounded so as to have a blending ratio of 30% by mass to 70% by mass was spun.

The spun composite fiber is cooled by cooling air 160 and further tensioned by drawing air 170 to a predetermined fineness (1.5 denier) and collected as it is on the collecting belt of the collecting conveyor 180. And it was deposited so that it might become a predetermined weight per unit area (15 g / m < ² >). Next, heat and pressure were applied to the deposited composite fiber with a hot embossing roll 190 to melt some fibers and entangle the fibers. Thereby, the nonwoven fabric of Example 1 was obtained. The nonwoven fabric of Example 1 is a single-layered nonwoven fabric composed of a nonwoven fabric mainly composed of an eccentric core-sheath type composite fiber.

<Manufacture of absorbent articles (diapers)>
The diaper was manufactured with the following manufacturing methods using the nonwoven fabric of Example 1 as a core wrap sheet.

First, an absorbent body (absorbent core) having a basis weight of 100 g / m ² composed of cotton-like pulp having a dry mass ratio of 100 to 100 and SAP is wrapped with a liquid-permeable core wrap sheet, and a mat-shaped core wrap type Absorber was produced. Next, by laminating a liquid-permeable top sheet on one surface of this mat-shaped core wrap type absorber, and by narrowing it through its nip while rotating an embossing roll pair having a convex embossing pattern on the surface, Embossed. By this embossing, a recess recessed from the top sheet side to the absorber side was formed on the top sheet side surface of the laminate of the core wrap type absorber and the top sheet, corresponding to the shape of the emboss pattern.

  The formed recesses were the lattice-like grooves 21 including the grooves 21a and 21b shown in FIG. The groove 21a and the groove 21b are formed in a single continuous groove structure that extends with an inclination (α, β) of 45 degrees with respect to the longitudinal direction of the absorber 13, respectively. The interval between the grooves 21b was 30 mm. The width of the opening of the groove 21 was 1.5 mm, and the depth of the groove 21 was 2 mm.

  Next, the embossed laminate is cut into a length required for one diaper using a cutting device, joined to a liquid-impermeable back sheet and a cover sheet excellent in touch, and processed into a diaper shape. Thus, the diaper of Example 1 was obtained.

[Example 2]
<Manufacture of composite fiber and nonwoven fabric>
The blending ratio of the polypropylene resin PP (melting point 162 ° C., MFR 40 g / 10 min) and the long-chain branched polypropylene resin PP1 (melting point 162 ° C., MFR 8 g / 10 min) in the first component is 95% by mass in terms of solid content: A nonwoven fabric of Example 2 was obtained in the same manner as Example 1 except that the amount was 5% by mass. The nonwoven fabric of Example 2 is a single-layered nonwoven fabric composed of a nonwoven fabric mainly composed of an eccentric core-sheath type composite fiber.

<Manufacture of absorbent articles (diapers)>
The nonwoven fabric of Example 2 was used as the top sheet, and the core wrap sheet was similar to Example 1 except that tissue paper having a basis weight of 12 g / m ² was used instead of the nonwoven fabric of Example 1. I got a diaper.

[Example 3]
<Manufacture of composite fiber and nonwoven fabric>
The blending ratio of the polypropylene resin PP (melting point 162 ° C., MFR 40 g / 10 min) and the long-chain branched polypropylene resin PP1 (melting point 162 ° C., MFR 8 g / 10 min) in the first component is 97% by mass in terms of solid content: 3% by mass, the first component and the second component are compounded so as to have a blending ratio of 10% by mass: 90% by mass, and a side-by-side type composite fiber structure is formed and discharged as a spinneret. A nonwoven fabric of Example 3 was obtained in the same manner as Example 1 except that a die having a constructed composite spinning nozzle was used. The nonwoven fabric of Example 3 is a single-layered nonwoven fabric made of a nonwoven fabric mainly composed of side-by-side type composite fibers.

<Manufacture of absorbent articles (diapers)>
A diaper of Example 3 was obtained in the same manner as in Example 1 except that the nonwoven fabric of Example 3 was used as a top sheet and a core wrap sheet, and the nonwoven fabric of Example 1 was not used.

[Example 4]
<Manufacture of composite fiber and nonwoven fabric>
The first component and the second component are combined so as to have a blending ratio of 40% by mass: 60% by mass, and an eccentric core-sheath composite type composite fiber structure is formed and discharged as a spinneret. A nonwoven fabric made of an eccentric core-sheath type composite fiber was obtained in the same manner as in Example 3 except that a die having a composite spinning nozzle was used.

  As the third component, polypropylene resin PP (melting point 162 ° C., MFR 40 g / 10 min) and organic additive (erucic amide 5% PP masterbatch made by Dainichi Seika Kogyo Co., Ltd. based on polypropylene resin) The component erucic acid amide is contained in an amount of 5% by mass))) and a mixture of 97% by mass and 3% by mass in terms of solid content. The third component was melted with an extruder to obtain a melt. Next, the melt of the third component is discharged from a spinneret having a spinning nozzle configured to discharge by forming a single structure fiber, and the third component has a blending ratio of 100% by mass. Single structure fibers were spun. In addition, in this specification, a single structure fiber means the fiber comprised with the same and uniform material in the cross section perpendicular | vertical to a longitudinal direction.

The spun single structure fiber is cooled with cooling air, and further tensioned with drawing air to a predetermined fineness (1.4 denier). It was collected on top and deposited so as to have a predetermined basis weight (5 g / m ² ). Next, heat and pressure were applied to the deposited composite fiber with a hot embossing roll 190 to melt some fibers and entangle the fibers. Thereby, the nonwoven fabric of Example 4 was obtained. The non-woven fabric of Example 4 is a non-woven fabric having a two-layer structure in which a non-woven fabric mainly composed of a single structure fiber (hereinafter also simply referred to as “single structure fiber non-woven fabric”) is laminated on a composite fiber non-woven fabric.

<Manufacture of absorbent articles (diapers)>
The nonwoven fabric of Example 4 was used as the top sheet, and the core wrap sheet was similar to Example 1 except that tissue paper having a basis weight of 12 g / m ² was used instead of the nonwoven fabric of Example 1. I got a diaper.

[Example 5]
<Manufacture of composite fiber and nonwoven fabric>
The long-chain branched polypropylene resin PP1 (melting point 162 ° C., MFR 8 g / 10 min) in the first component was changed to the long-chain branched polypropylene resin PP2 (melting point 162 ° C., MFR 4 g / 10 min), and the polypropylene resin in the first component Implemented except that the blending ratio of PP (melting point 162 ° C., MFR 40 g / 10 min) and long chain branched polypropylene resin PP2 (melting point 162 ° C., MFR 8 g / 10 min) was 97% by mass: 3% by mass in terms of solid content. In the same manner as in Example 1, a nonwoven fabric made of an eccentric core-sheath type composite fiber was obtained.

In addition, a single structure fiber having a blending ratio of 100% by mass of the third component is spun on both sides as well as on one side of the composite fiber nonwoven fabric so that a predetermined basis weight (5 g / m ² ) is obtained. A nonwoven fabric of Example 5 was obtained in the same manner as in Example 4 except that a monostructural fiber nonwoven fabric was laminated. The nonwoven fabric of Example 5 is a nonwoven fabric having a three-layer structure in which one single-structure fiber nonwoven fabric is laminated on both surfaces of a nonwoven fabric composed of an eccentric core-sheath type composite fiber.

<Manufacture of absorbent articles (diapers)>
A diaper of Example 5 was obtained in the same manner as Example 1 except that the nonwoven fabric of Example 5 was used as a top sheet and a core wrap sheet, and the nonwoven fabric of Example 1 was not used.

[Comparative Example 1]
<Manufacture of composite fiber and nonwoven fabric>
A nonwoven fabric of Comparative Example 1 was obtained in the same manner as in Example 1 except that long-chain branched polypropylene resin PP1 (melting point: 162 ° C., MFR: 8 g / 10 minutes) was not blended with the first component. The nonwoven fabric of Comparative Example 1 is a nonwoven fabric having a single-layer structure made of a nonwoven fabric mainly composed of an eccentric core-sheath type composite fiber.

<Manufacture of absorbent articles (diapers)>
The non-woven fabric of Comparative Example 1 was used as the top sheet, and the core wrap sheet was similar to Example 1 except that tissue paper having a basis weight of 12 g / m ² was used instead of the non-woven fabric of Example 1. I got a diaper.

[Comparative Example 2]
<Manufacture of composite fiber and nonwoven fabric>
Except that the long-chain branched polypropylene resin PP1 (melting point 162 ° C., MFR 8 g / 10 min) in the first component was changed to the long-chain branched polypropylene resin PP3 (melting point 162 ° C., MFR 2 g / 10 min), the same as in Example 2. The composite fiber was spun. The nonwoven fabric of Comparative Example 2 was not obtained due to poor spinning.

[Comparative Example 3]
<Manufacture of composite fiber and nonwoven fabric>
The blending ratio of the polypropylene resin PP (melting point 162 ° C., MFR 4 g / 10 min) and the long-chain branched polypropylene resin PP1 (melting point 162 ° C., MFR 8 g / 10 min) in the first component is 85% by mass in terms of solid content: The composite fiber was spun in the same manner as in Example 1 except that the content was 15% by mass. The nonwoven fabric of Comparative Example 3 was not obtained due to poor spinning.

[Comparative Example 4]
<Manufacture of composite fiber and nonwoven fabric>
A nonwoven fabric of Comparative Example 4 was obtained in the same manner as in Example 4 except that the first component and the second component were combined so as to have a blending ratio of 5% by mass to 95% by mass. The nonwoven fabric of Comparative Example 4 is a single-layered nonwoven fabric composed of a nonwoven fabric mainly composed of an eccentric core-sheath type composite fiber.

<Manufacture of absorbent articles (diapers)>
The diaper of the comparative example 4 was obtained like Example 1 except having used the nonwoven fabric of the comparative example 4 as a top sheet and a core wrap sheet | seat, and not using the nonwoven fabric of the example 1. FIG.

[Comparative Example 5]
<Manufacture of composite fiber and nonwoven fabric>
A nonwoven fabric of Comparative Example 5 was obtained in the same manner as in Example 4 except that the first component and the second component were combined so as to have a blending ratio of 50% by mass: 50% by mass. The nonwoven fabric of Comparative Example 5 is a single-layered nonwoven fabric made of a nonwoven fabric mainly composed of an eccentric core-sheath type composite fiber.

[Comparative Example 6]
<Manufacture of composite fiber and nonwoven fabric>
Polypropylene resin PP (melting point 162 ° C., MFR 40 g / 10 min), low crystalline polyolefin resin PP1 (melting point 52 ° C., MFR 50 g / 10 min) and organic additive (erucamide 5% PP master) in the second component Batch (based on polypropylene resin and containing 5% by mass of active ingredient erucamide) and inorganic pigment (50% titanium oxide PP masterbatch (based on polypropylene resin and 50% by mass of active ingredient titanium oxide) The composite fiber was spun in the same manner as in Example 4 except that the blending ratio was 56% by mass: 20% by mass: 4% by mass: 20% by mass in terms of solid content. The nonwoven fabric of Comparative Example 6 was not obtained due to poor spinning.

[Comparative Example 7]
<Manufacture of composite fiber and nonwoven fabric>
Other than changing the predetermined basis weight of the nonwoven fabric made of composite fiber from 15 g / m ² to 46 g / m ² and changing the predetermined basis weight of the nonwoven fabric made of single structure fiber from 5 g / m ² to 13 g / m ² Produced a nonwoven fabric of Comparative Example 7 in the same manner as in Example 5. The nonwoven fabric of Comparative Example 7 is a nonwoven fabric having a three-layer structure in which one single-structure fiber nonwoven fabric is laminated on both surfaces of a nonwoven fabric composed of an eccentric core-sheath type composite fiber.

<Manufacture of absorbent articles (diapers)>
A diaper of Comparative Example 7 was obtained in the same manner as in Example 1 except that the nonwoven fabric of Comparative Example 7 was used as the core wrap sheet and the nonwoven fabric of Example 1 was not used.

[Comparative Example 8]
<Manufacture of composite fiber and nonwoven fabric>
Polypropylene resin PP (melting point 162 ° C., MFR 40 g / 10 min), low crystalline polyolefin resin PP1 (melting point 52 ° C., MFR 50 g / 10 min) and organic additive (erucamide 5% PP master) in the second component Batch (based on polypropylene resin and containing 5% by mass of active ingredient erucamide) and inorganic pigment (50% titanium oxide PP masterbatch (based on polypropylene resin and 50% by mass of active ingredient titanium oxide) The non-woven fabric of Comparative Example 8 is obtained in the same manner as in Example 4 except that the blending ratio is 94% by mass: 0% by mass: 4% by mass: 2% by mass in terms of solid content. The nonwoven fabric of Comparative Example 8 is a two-layered nonwoven fabric in which a single structure fiber nonwoven fabric is laminated on a composite fiber nonwoven fabric.

<Manufacture of absorbent articles (diapers)>
The nonwoven fabric of Comparative Example 8 was used as the top sheet, and the core wrap sheet was the same as Example 1 except that tissue paper with a basis weight of 12 g / m ² was used instead of the nonwoven fabric of Example 1. I got a diaper.

[Comparative Example 9]
<Manufacture of composite fiber and nonwoven fabric>
Polypropylene resin PP (melting point 162 ° C., MFR 40 g / 10 min), low crystalline polyolefin resin PP1 (melting point 52 ° C., MFR 50 g / 10 min) and organic additive (erucamide 5% PP master) in the second component Batch (based on polypropylene resin and containing 5% by mass of active ingredient erucamide) and inorganic pigment (50% titanium oxide PP masterbatch (based on polypropylene resin and 50% by mass of active ingredient titanium oxide) The mixing ratio is 34% by mass: 60% by mass: 4% by mass: 2% by mass in terms of solid content, and the first component and the second component are 30% by mass: 70% by mass. The composite fiber was spun in the same manner as in Example 4 except that it was compounded so as to have a blending ratio of%, although spinning was possible, but the texture of the laminated composite fiber was poor. There was therefore discontinued production of nonwovens.

(Test items)
About the Example and the comparative example, the evaluation test of the following items was done.

I. Spinning properties of composite fibers During the production of composite fibers, in the process of discharging a melt of fiber-forming components from a nozzle (nozzle) and drawing with drawing air, problems such as poor spinning due to fusion of yarns or yarn breakage It was visually confirmed whether or not the operation could be performed without any occurrence. The evaluation criteria were as follows.
○: Spinning was performed without any problem, and the uniformity of the fiber was good.
Spinning failure: Spinning was not performed properly due to yarn breakage or the like.
Unsatisfactory formation: Although spinning was possible, the non-woven fabric (layer) obtained by fusing fibers was inferior in texture.

II. Crimpability of composite fiber A fiber obtained by a production process of a composite fiber, that is, a composite fiber that has been spun, cooled, stretched, and drawn to a predetermined fineness, in accordance with Japanese Industrial Standard JIS L1015, The number of crimps of the fiber per 25 mm was determined.

III. Average fiber diameter of non-woven fabric (denier)
Using an electron microscope (S-3500N manufactured by Hitachi, Ltd.), a photograph of the fiber nonwoven fabric at a magnification of 1000 times was taken. Arbitrary 100 fibers were selected from the fibers constituting the fiber nonwoven fabric, and the width (diameter) of the selected fibers was measured. The average of the measurement results was taken as the average fiber diameter.

IV. Maximum pore size (μm), minimum pore size (μm) and average pore size (μm) of nonwoven fabric
Fluorine-based inert liquid (manufactured by 3M Co., Ltd.) was used to remove test pieces collected from non-woven fabric in a temperature-controlled room at a temperature of 20 ± 2 ° C. and a humidity of 65 ± 2% as defined in Japanese Industrial Standards JIS Z8703. Fluorinert), using Porous materials, Inc. Capillary Flow Porometer “Model: CFP-1200AE”, maximum pore size (μm), minimum pore size (μm) and average pore size ( μm).

V. Nonwoven fabric porosity (%)
About the arbitrary location of the nonwoven fabric, based on JIS1096, thickness was measured under 0.7 kPa for 10 seconds using the thickness measuring device. From the result, the basis weight of the nonwoven fabric, and the raw material density used for the nonwoven fabric, the porosity was calculated by rounding off the first decimal place of the numerical value obtained by the following formula. However, when the obtained non-woven fabric was a laminate, a single-layer non-woven fabric obtained by removing a spunbonded non-woven fabric mainly composed of non-crimped fibers was measured.

    Porosity (%) = [1- (Weight / Thickness / Density)] × 100

VI. Bulkiness of non-woven fabric A non-woven fabric sample is cut into a 20 cm square shape, and one set of 8 sheets is taken as one sample, using a compression tester (KES-FB3-AUTO-A, manufactured by Kato Tech Co., Ltd.) according to the following setting conditions. The measurement was performed. One sample was measured at three measurement points, and the average value of the three points was obtained.

VII. Wrinkle of non-woven fabric Cut a non-woven fabric sample into a 20cm square shape, set it on a tensile / shear tester (KES-FB1-AUTO-A, manufactured by Kato Tech Co., Ltd.), and measure shear force under standard measurement conditions. Went. Regarding the obtained shear angle-shear force data, the change rate DO + of the straight line portion near the shear angle 0 ° in the positive direction, the change rate Dmax + near the maximum shear angle, and the shear angle 0 in the negative direction.
The rate of change DO− of the straight line portion near ° and the rate of change Dmax− near the minimum shear angle were determined. The average value of the change rate DO + and the change rate DO− is DO, and the change rate Dmax + and the change rate Dmax
The ratio DO / Dmax of the change rate was calculated with the average value of − as Dmax.

  When evaluating the above-mentioned Dmax, the state of wrinkles near the maximum shear angle was visually confirmed. The evaluation criteria were the following four-level evaluation (indicated by the symbols ◎, ○, Δ, × in order from the highest evaluation). The most applicable evaluation was adopted with a parameter (N) of 30.

◎: No wrinkles ○: Wrinkles with slight undulation are visible on the surface △: Wrinkles with a wide pitch are observed ×: Wrinkles with a fine pitch are observed

VIII. Diaper feel (feel)
The non-woven fabric created in this example is processed into a paper diaper as a cover sheet, and 50 subjects are given a sense of touch with a sensory evaluation on a five-point scale (shown as one of the numbers 1 to 5 where 5 is the best). The average value of 50 persons was used as the evaluation value of the touch feeling.

IX. Number of diapers that were torn The diaper was held with one hand and was swung up and down to reciprocate at a distance of 30 cm in 1 second. This was repeated 10 times. Subsequently, the appearance was visually confirmed, and a case where there was a tear or a content (SAP) leaked out was determined to be “has been torn”. Fifty test subjects were asked to perform this test, and the number determined to be broken was counted. The smaller the number, the harder it is to tear and the better the performance.

(Test results)
The test results are shown in FIGS.

  All of the conjugate fibers according to the present invention had good spinnability.

  Moreover, the bulkiness of the nonwoven fabric according to the present invention was significantly higher than that of the comparative example.

(effect)
When a sheet made of a nonwoven fabric using the conjugate fiber of the example according to the present embodiment is used as a sheet covering at least a part of the absorbent body of the water absorbent article according to the present embodiment, the sheet is made into a water absorbent article by embossing. When forming the dent toward the absorber side from the sheet side, even if the sheet is pulled toward the dent, the sheet is hardly broken. In addition, even when there is a relatively hard material such as SAP particles under the sheet, the material can be prevented from leaking through the sheet in the vicinity of the portion squeezed to form the dent or in the vicinity thereof.

  As is apparent from the above examples and comparative examples, the diaper using the nonwoven fabric using the conjugate fiber of the present embodiment for the core wrap and / or the top sheet has a problem of tearing compared to the diaper not using the core wrap. Was found to be improved.

  When the nonwoven fabric using the composite fiber of this Embodiment was used for the top sheet (sheet located in the surface layer side), it turned out that tactile feeling is favorable. Even when the nonwoven fabric using the conjugate fiber of the present embodiment is used for the core wrap, the tactile sensation is better than when the nonwoven fabric using the conjugate fiber of the present embodiment is not used for any sheet. I understood that.

  In particular, it was found that when the nonwoven fabric using the conjugate fiber of the present embodiment was used for the top sheet (sheet positioned on the surface layer side), the generation of wrinkles was well prevented. It was found that the generation of wrinkles was also prevented when the nonwoven fabric using the conjugate fiber of the present embodiment was used for the core wrap.

  Below, the example of the preferable aspect of the composite fiber by this Embodiment is shown.

[1] A composite fiber comprising a first component and a second component which are fiber-forming components,
The first component and the second component are each composed mainly of a thermoplastic resin,
The first component includes a long-chain branched structure polyolefin resin,
The long-chain branched polyolefin resin is a composite fiber having a melt flow rate measured at a load of 2.16 kg and a temperature of 230 ° C. in accordance with ASTM D1238 of 4 g / 10 min or more.

  The long-chain branched polyolefin resin has a structure in which long side chains are branched, so that fluidity in a molten state is lowered. Therefore, if spinning is performed using a thermoplastic resin containing a long-chain branched polyolefin resin as a raw material, when the yarn extruded from the spinning die is drawn by drawing air, the molecular orientation of the yarn tends to advance and the crystal Is promoted. The crystallization of one of the fiber-forming components of the composite fiber is accelerated and hardened, so that the difference in elasticity with the other increases, so that the composite fiber containing the long-chain branched structure polyolefin resin is crimpable The degree of. Moreover, the nonwoven fabric using the composite fiber which mix | blended long-chain branched structure polyolefin resin is easy to be bulky, is excellent in cushioning properties, and becomes difficult to wrinkle even if it receives shear deformation.

[2] The first component includes the long-chain branched polyolefin resin in an amount of 0.5% by mass or more and 10% by mass or less based on the total solid content of the first component. The composite fiber according to [1].

  When the amount of the long-chain branched polyolefin in the first component is within this range, the effect of increasing the degree of crimping of the composite fiber is significant, and the spinnability is also good. When the long-chain branched structure polyolefin in the first component is less than 0.5% by mass, the effect of increasing the degree of crimping of the composite fiber is reduced, and when it is more than 10% by mass, the spinnability is lowered. There is a tendency.

[3] The composite fiber includes the first component in an amount of 10% by mass or more and 40% by mass or less based on the total solid content of the composite fiber, [1] or [2] The composite fiber described in 1.

[4] The first component and the second component each include a thermoplastic resin in an amount of 90% by mass or more and 100% by mass or less based on the total solid content of each component. The composite fiber according to any one of [1] to [3].

  The amount of the thermoplastic resin can be appropriately set from the viewpoint of spinnability and strength of the composite fiber.

[5] The composite fiber according to any one of [1] to [4], wherein each of the first component and the second component is mainly composed of polypropylene.

  From the viewpoint of spinnability and strength of the composite fiber, polypropylene (PP) is preferably used as the thermoplastic resin.

[6] The composite according to any one of [1] to [5], wherein the first component is mainly composed of polypropylene, and the long-chain branched structure polyolefin resin is a long-chain branched structure polypropylene. fiber.

  When a polypropylene resin is used as the long-chain branched polyolefin resin, it is preferable to use a polypropylene resin as the first component thermoplastic resin from the viewpoint of compatibility.

[7] The composite fiber according to any one of [1] to [6], wherein the composite fiber is a core-sheath type composite fiber having the first component as a core component and the second component as a sheath component. The composite fiber described in 1.

[8] The composite fiber according to [7], wherein the core-sheath composite fiber is an eccentric core-sheath composite fiber.

[9] The composite fiber according to any one of [1] to [6], wherein the composite fiber is a side-by-side type composite fiber.

  As shown in [7] to [9], the composite fiber according to the present embodiment includes a first component containing a long-chain branched polyolefin resin and a second component different from the first component. The composite fiber is disposed in an asymmetric zone in a cross section perpendicular to the longitudinal direction. Compared with the second component, the first component has a higher crimpability because the molecular orientation is easier to proceed and the crystallization is more easily promoted when being spun and stretched. Moreover, the nonwoven fabric using this conjugate fiber has good stretchability and cushioning properties, and is bulky.

[10] At least one of the first component and the second component includes the following a) to g),
a) Mesopentad fraction [mmmm] is 30 mol% or more and 80 mol% or less,
b) Racemic pentad fraction [rrrr] and 1- [ mmmm] satisfy the relationship [rrrr] / 1- [ mmmm] ≦ 0.1,
c) the racemic meso racemic meso pentad fraction [rmrm] is greater than 2.5 mol%,
d) Mesotriad fraction [mm], racemic triad fraction [rr], and triad fraction [mr] satisfy the relationship [mm] × [rr] / [mr] ² ≦ 2.0,
e) The weight average molecular weight [Mw] is 10,000 or more and 200,000 or less,
f) The weight average molecular weight [Mw] and the number average molecular weight [Mn] satisfy the relationship of molecular weight distribution [Mw] / [Mn] ≦ 4,
g) The amount of the extract by boiling diethyl ether is 0% by mass or more and 10% by mass or less based on the total solid content of the low crystalline polyolefin resin.
The composite fiber according to any one of [1] to [9], wherein the low crystalline polyolefin resin satisfying the above requirement is included in an amount of 5% by mass or more and 50% by mass or less based on the total solid content.

  The low crystalline polyolefin resin is difficult to produce crystals because the side chain protruding directions are not uniform, and the fibers and nonwoven fabrics using the low crystalline polyolefin resin tend to be soft, small and soft to the touch.

[11] A top sheet for an absorbent article comprising an absorbent body and a top sheet, the top sheet comprising a nonwoven fabric made of the conjugate fiber according to any one of [1] to [10] .

  By using the non-woven fabric according to the present embodiment as the top sheet, the absorbent article can be provided with a good touch for the user in addition to being bulky and difficult to wrinkle.

[12] A core wrap sheet for a core wrap type absorbent body including an absorbent core and a core wrap sheet surrounding the absorbent core, the nonwoven fabric comprising the conjugate fiber according to any one of [1] to [10] A core wrap sheet comprising:

  By using the non-woven fabric according to the present embodiment as the core wrap sheet, the core wrap type absorbent body can be provided with a bulkiness and difficulty in forming wrinkles. As a result, the absorbent body including the core wrap type absorbent body The article can provide a good touch for the user.

[13] An absorbent article including a top sheet, an absorber, and a back sheet, wherein at least one of the top sheet, the absorber, and the back sheet is a composite according to [1] to [10] An absorbent article comprising a non-woven fabric made of fibers.

  When the non-woven fabric according to the present embodiment is used as the back sheet, it is difficult to wrinkle, and the appearance can be provided.

10 Disposable Diaper 10F Front Body Area 10R Back Body Area 10C Inseam Area 10W Waist Around Opening 10L Leg Around Opening 10J Closure 10T Waste Tape 11 Cover Sheet 11A Notch 11B Inner Cover Sheet 11C Outer Cover Sheet 12 Back Sheet ( Back sheet)
13 Absorbent body 13B Hydrophilic sheet 13C Core wrap type absorbent body 14 Top sheet (surface sheet)
15, 17 Thread rubber 18 Side sheet 19 Thread rubber 21 Recess (groove)
21a 1st groove 21b 2nd groove 22 Press part 24 Flat part 1001 Eccentric core-sheath type composite fiber 1002 Side-by-side type composite fiber 1010, 1110 1st component 1020, 1120 2nd component 1130, 1140 Extruder 1150 Nozzle (nozzle )
1160 Air for cooling 1170 Air for drawing 1180 Collection conveyor 1190 Heat embossing roll 1200 Winder G Composite fiber nonwoven fabric layer H Single-structure fiber nonwoven fabric layer

Claims (6)

A composite fiber comprising a first component and a second component which are fiber-forming components,
The first component and the second component are each composed mainly of a thermoplastic resin,
The first component includes a long-chain branched structure polyolefin resin,
The long-chain branched structure polyolefin resins, ASTM D1238 load 2.16kg in compliance with state, and are melt flow rate of 4g / 10 minutes or more as measured at a temperature 230 ° C.,
The first component includes the long-chain branched structure polyolefin resin in an amount of 0.5% by mass or more and 10% by mass or less based on the total solid content of the first component;
The conjugate fiber includes the first component in an amount of 10% by mass or more and 40% by mass or less based on the total solid content of the conjugate fiber,
The first component and the second component are each composed mainly of polypropylene,
The first component is mainly composed of polypropylene, and the long chain branched structure polyolefin resin is a long chain branched structure polypropylene,
Composite fiber characterized Rukoto wherein the first component second component are arranged in a non-target zones in a cross section perpendicular to the longitudinal direction of the composite fibers.   The first component and the second component each include a thermoplastic resin in an amount of 90% by mass or more and 100% by mass or less based on the total solid content of each component. The conjugate fiber described. The composite fiber according to claim 1 or 2 , wherein the composite fiber is a core-sheath type composite fiber in which the first component is a core component and the second component is a sheath component. The composite fiber according to claim 3 , wherein the core-sheath type composite fiber is an eccentric core-sheath type composite fiber. The composite fibers are characterized by a side-by-side type composite fiber, the composite fiber according to claim 1 or 2. At least one of the first component and the second component includes the following a) to g):
a) Mesopentad fraction [mmmm] is 30 mol% or more and 80 mol% or less,
b) The racemic pentad fraction [rrrr] and 1- [mmmm] satisfy the relationship [rrrr] / 1- [mmmm] ≦ 0.1,
c) the racemic meso racemic meso pentad fraction [rmrm] is greater than 2.5 mol%,
d) Mesotriad fraction [mm], racemic triad fraction [rr], and triad fraction [mr] satisfy the relationship [mm] × [rr] / [mr] ² ≦ 2.0,
e) The weight average molecular weight [Mw] is 10,000 or more and 200,000 or less,
f) The weight average molecular weight [Mw] and the number average molecular weight [Mn] satisfy the relationship of molecular weight distribution [Mw] / [Mn] ≦ 4,
g) The amount of the extract by boiling diethyl ether is 0% by mass or more and 10% by mass or less based on the total solid content of the low crystalline polyolefin resin.
The composite fiber according to any one of claims 1 to 5 , wherein the low crystalline polyolefin resin satisfying the above condition is contained in an amount of 5% by mass or more and 50% by mass or less based on the total solid content.

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