JP6654866B2 - Nonwoven fabric, method for producing the same, and sheet for absorbent article - Google Patents

Description

  The present disclosure relates to a nonwoven fabric using splittable conjugate fibers, a method for producing the same, and a sheet for an absorbent article.

  Various nonwoven fabrics using splittable composite fibers that can be split into a plurality of components by external force have been proposed. The splittable conjugate fiber behaves like a single fiber at the stage of producing a fibrous web, and after the fibrous web is produced, a splitting process in which physical pressure is applied to split each component, for example, a high-pressure water jet process, or a so-called needle punch By being subjected to the treatment, it is divided into a plurality of components to form ultrafine fibers. Nonwoven fabrics containing ultrafine fibers are used as sanitary articles (for example, sanitary products, disposable diapers), wipers, and base fabrics for artificial leather, utilizing the soft touch, denseness, or good wiping properties of the ultrafine fibers. Used. A nonwoven fabric obtained by splitting splittable conjugate fibers using high-pressure water flow treatment is described in, for example, Patent Document 1.

  Further, as a splittable conjugate fiber, a heat splittable conjugate fiber which is made of a resin having higher heat shrinkability and which can be split by heat treatment, has been proposed. A nonwoven fabric formed using such a heat-division conjugate fiber is proposed in Patent Document 2. Patent Literature 2 discloses a nonwoven fabric which is obtained by dividing a heat-splitting conjugate fiber by a heat treatment and a pressure treatment and has an excellent tactile sensation and dust collecting ability.

JP-A-8-260316 JP-A-9-273601

  The present embodiment has been made for the purpose of providing a flexible nonwoven fabric by suppressing the splitting of splittable conjugate fibers.

In one aspect, the present disclosure provides a nonwoven fabric that includes a splittable conjugate fiber in an amount of 20% by mass or more, and the fibers are bonded to each other by one component of the splittable conjugate fiber (hereinafter, “A component”) to form an adhesive portion. And
The splittable conjugate fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less,
Splittable conjugate fiber, the melting point of component A is taken as T _A ° C., when heated for 60 seconds at T A _-5 ° C., it is of non-thermal splitting may not occur delamination between the sections,
Provide a non-woven fabric.

According to another aspect of the present disclosure, a nonwoven fabric containing splittable conjugate fibers of 20% by mass or more, and the fibers are bonded to each other by one component (hereinafter, referred to as “component A”) of the splittable conjugate fibers to form an adhesive portion And
The splittable conjugate fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less,
An ultrafine fiber formed by splitting or exfoliating one of the plurality of sections constituting the splittable conjugate fiber is not continuously present at a length exceeding 30% of the fiber length of the splittable conjugate fiber. ,
Provide a non-woven fabric.

The present disclosure provides, in yet another summary,
Producing a fibrous web containing at least 20% by mass of splittable conjugate fiber. Hot air processing is performed on the fibrous web to apply hot air at a temperature at which the lowest melting point component among the components constituting the splittable conjugate fiber softens or melts. Including doing
Without subjecting the fibrous web to mechanical entanglement,
Provided is a method for producing a nonwoven fabric, in which hot air processing is performed without applying a linear pressure of 10 kg / cm or more to a fiber web.

  The nonwoven fabric of the present embodiment has a soft touch because the splitting of the splittable conjugate fiber is suppressed, and the adhesive portion is formed by melting or softening the components of the small section constituting the splittable conjugate fiber. .

FIG. 1 is a perspective view showing a state in which an ultrafine fiber is formed in a part of the splittable conjugate fiber. FIG. 2 is an electron micrograph of the surface of the nonwoven fabric of Example 1. FIG. 3 is an electron micrograph of the surface of the nonwoven fabric of Example 1. FIG. 4 is an electron micrograph of a cross section of the nonwoven fabric of Example 1. FIG. 5 is an electron micrograph of the surface of the nonwoven fabric of Comparative Example 1. FIG. 6 is an electron micrograph of a cross section of the nonwoven fabric of Comparative Example 1.

(History leading to this embodiment)
In general, splittable conjugate fibers are used to produce a fabric such as a nonwoven fabric containing ultrafine fibers, utilizing the property of splitting into a plurality of components by an external force or a heat shrinkage force of a component. However, the present inventors can make use of the structure of the splittable conjugate fiber formed by assembling a plurality of small sections by not actively splitting the splittable conjugate fiber, and have an unprecedented feel or characteristics. We thought that a nonwoven fabric could be obtained. Therefore, as a splittable conjugate fiber, a splittable conjugate fiber that can be split by external force but does not exhibit heat splitting properties is used, and a heat-bonding process is performed by hot-air processing so that splitting is unlikely to produce a heat-bonded nonwoven fabric. As a result, they have found that a flexible nonwoven fabric can be obtained. Furthermore, the present inventors have found that a heat-bonded nonwoven fabric produced using a splittable conjugate fiber has higher transparency than a heat-bonded nonwoven fabric produced using a core-sheath conjugate fiber.
Hereinafter, the nonwoven fabric of the present embodiment will be described.

(Split type composite fiber)
The nonwoven fabric of the present embodiment contains splittable conjugate fibers. The splittable conjugate fiber refers to a fiber that can be split into a plurality of components by an external force or a heat shrinkage force of a component. In the nonwoven fabric of the present embodiment, since splitting of the splittable conjugate fiber is suppressed, the splittable conjugate fiber still exists in a state having splitting ability.

In the present embodiment, as the splittable conjugate fiber, one having no heat splitting property is preferably used. Specifically, when the melting point of the component (hereinafter, referred to as “component A”) having the lowest melting point among the components constituting the splittable conjugate fiber and forming an adhesive portion in the nonwoven fabric is T _A ° C, T _A A splittable conjugate fiber that does not cause separation between sections when heated at -5 ° C for 60 seconds is preferably used. Delamination between the sections, in the fiber side after heating for 60 seconds at T A _-5 ° C., among the plurality of sections constituting the splittable conjugate fiber, one section peeled or separated to form a microfine fiber Is determined to have occurred. When the peeling occurs between sections in the splittable conjugate fibers to mechanical force is applied, when heated for 60 seconds at T A _-5 ° C., no peeling between the new section These fibers are also preferably used in the present embodiment as splittable conjugate fibers having no heat splitting property. When a splittable conjugate fiber having no heat splitting property is used, the splitting of the splittable conjugate fiber does not progress when subjected to hot air processing, and the formation of ultrafine fibers is suppressed, so that many ultrafine fibers are formed. A nonwoven fabric having high sheer feeling (transparency) can be obtained as compared with a nonwoven fabric that has been made. When the nonwoven fabric containing such splittable conjugate fibers is used as a surface sheet of an absorbent article, or a sheet disposed between the surface sheet and the absorber, the nonwoven fabric is formed by splitting splittable conjugate fibers. The liquid permeation rate is higher than that of the non-woven fabric containing a large amount of ultrafine fibers, and the surface in contact with the skin of the user is less likely to be wet by the liquid returning from the absorber.

  In the splittable conjugate fiber, at least one of the constituent components is divided into two or more in the fiber cross section, at least a part of the constituent component is exposed on the fiber surface, and the exposed portion is continuous in the fiber length direction. It has a fiber cross-sectional structure that is formed in a uniform manner. The splittable conjugate fiber used in the present embodiment is composed of two or more components, and among the two or more components, the component having the lowest melting point (component A) plays a role in bonding the fibers. Preferably, the component A is a thermoplastic resin having a melting point of 140 ° C. or less, more preferably 136 ° C. or less. On the other hand, the components other than the component A are thermoplastic resins having a melting point exceeding 140 ° C. Here, the melting point is a melting point of the resin after forming the fiber, and is determined from a DSC curve measured according to JIS K7121 (1987). The melting point of the component A is preferably 10 ° C. or more, more preferably 15 ° C. or more lower than the melting points of the other components.

  Components constituting the splittable conjugate fiber are not particularly limited, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and copolymers thereof, and polypropylene. , Polyethylene (including high density polyethylene, low density polyethylene, linear low density polyethylene, etc.), polybutene-1, ethylene-propylene copolymer, ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, etc. And a polyamide-based resin such as nylon 6, nylon 12, and nylon 66.

The splittable conjugate fiber is composed of, for example, two components of the component _A and a resin component having a melting point higher by 10 ° C. or more than the melting point TA of the component _A (hereinafter, “component B”). Good. In that case, the combination of components constituting the splittable conjugate fiber is polyethylene terephthalate / polyethylene, polypropylene / polyethylene, etc. (Polyethylene is any one of high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. Or a combination thereof). Polyethylene melts at a relatively low temperature and adheres the fibers to each other satisfactorily. When the polyethylene is a high-density polyethylene, its heat shrinkage is higher than that of other thermoplastic resins obtained by polymerizing ethylene as a monomer, such as low-density polyethylene, linear low-density polyethylene, and ethylene-propylene copolymer. Because of the low splitting property, the heat splitting property of the splittable conjugate fiber can be reduced. Therefore, even if the splittable conjugate fiber containing the high-density polyethylene as the component A is subjected to a heat treatment for thermal bonding, the sections containing the high-density polyethylene do not significantly shrink and the separation between the sections is further suppressed. Is preferred. Further, when the high melting point component to be combined with the component A is a polyester resin having a high melting point such as polyethylene terephthalate, when the component A is polyethylene, the temperature difference between the melting points of the polyethylene and the polyethylene is large. Is preferable because the bulk is not easily reduced. In addition, polyester resins such as polyethylene terephthalate are preferable because the resin itself has a high modulus of elasticity, and the splittable conjugate fiber and the nonwoven fabric containing the resin have a “stiffness” and the bulkiness of the nonwoven fabric is easily increased.

The fineness of the splittable conjugate fiber is preferably from 0.6 dtex to 6 dtex, more preferably from 0.8 dtex to 4.8 dtex, even more preferably from 1.2 dtex to 3.5 dtex, and most preferably. Is not less than 1.5 dtex and not more than 2.5 dtex.
Also, the number of sections in the splittable conjugate fiber (that is, the number of divisions into each component in the splittable conjugate fiber) is, for example, preferably 4 or more and 32 or less, and preferably 4 or more and 20 or less. Is more preferable, and the number is most preferably 6 or more and 16 or less. When the splittable conjugate fiber is composed of two components, the A component and the B component, the number of sections of each component is preferably 3 or more and 8 or less, and the total number of sections is 6 or more and 16 or less. Is preferred.

  If the number of sections is small, the area and volume per section will be large, the area and / or volume of the bonded portion will be large, and the feel of the nonwoven fabric may be hard. Further, in order to reduce the number of sections and the area and volume per section, it is necessary to reduce the fineness of the splittable conjugate fiber itself. However, the splittable conjugate fiber having a small fineness is manufactured. And it may reduce the productivity of the nonwoven fabric. On the other hand, in a splittable conjugate fiber having a large number of sections, the area exposed to the fiber surface per section becomes small depending on the shape of the fiber cross section. As a result, the area of the bonding point formed by the component A also becomes small, and the tensile strength of the obtained nonwoven fabric may be insufficient, or the surface may become fluffy. In addition, such a splittable conjugate fiber having a large number of sections needs to be manufactured by using a complicated spinning nozzle and strictly controlling the melt spinning conditions. Therefore, the use of such splittable conjugate fibers may increase the production cost of the nonwoven fabric.

  The shape of the section is not particularly limited. For example, the splittable conjugate fiber may be one in which wedge-shaped sections are arranged in a chrysanthemum shape. Alternatively, the splittable conjugate fiber may be one in which sections are arranged in layers in a fiber cross section. Also, the splittable conjugate fiber may be a so-called solid splittable conjugate fiber that does not have a cavity portion that is continuous in the length direction when the fiber cross section is observed, or may be one or more cavities that are continuous in the length direction. A so-called hollow split type composite fiber having a portion may be used. From the viewpoint of suppressing splitting, solid splittable conjugate fibers are preferably used.

  The volume ratio of the components constituting the splittable conjugate fiber may be determined, for example, so that the section of the component A has a desired area and volume. For example, when a splittable conjugate fiber is composed of two components, component A and component B, the volume ratio is preferably from 2: 8 to 8: 2 (component A: component B). When the volume ratio is within the above range, the productivity of the conjugate fiber tends to increase, and the bonded portion can be formed favorably in the nonwoven fabric. The more preferable volume ratio of the component A: B is 4: 6 to 6: 4.

  The fiber length of the splittable conjugate fiber is 10 mm or more and 100 mm or less. Since the splittable conjugate fiber may be split by the force applied when the fiber is cut, if the fiber length is less than 10 mm, the number of ultrafine fibers formed by splitting the splittable conjugate fiber in the nonwoven fabric increases. For example, the transparency of the nonwoven fabric may decrease. On the other hand, if the fiber length is less than 10 mm, a bulky fiber web is difficult to obtain, and a fiber web cannot be produced by a card method using a parallel card machine or the like. If the fiber length of the splittable conjugate fiber exceeds 100 mm, it may be difficult to produce a fibrous web using, for example, a carding machine. In the case of a low-weight nonwoven fabric, if the fiber length exceeds 100 mm, the number of fibers constituting the nonwoven fabric is reduced, and thus the formation of the nonwoven fabric may not be stable, or the required strength of the nonwoven fabric may not be obtained. There is. The fiber length is more preferably 25 mm or more and 100 mm or less, still more preferably 32 mm or more and 70 mm or less, and particularly preferably 38 mm or more and 65 mm or less.

(Other fibers)
The nonwoven fabric of the present embodiment may include fibers other than the splittable conjugate fiber. Other fibers are not particularly limited, and include, for example, natural fibers such as cotton, silk and wool, viscose rayon, cupra, and solvent-spun cellulose fibers (eg, Lentinglyocell (registered trademark) and Tencel (registered trademark)). Regenerated fibers, polyolefin fibers, polyester fibers and polyamide fibers, single fibers of (poly) acryl made of acrylonitrile, and fibers made of engineering plastics such as polycarbonate, polyacetal, polystyrene and cyclic polyolefin may be used. . Further, as other fibers, not only a single fiber made of one kind of thermoplastic resin but also a conjugate fiber made of two or more kinds of thermoplastic resins other than the splittable conjugate fiber (for example, concentric or eccentric core-sheath) Type composite fiber, sea-island type composite fiber, side-by-side type composite fiber). The other fiber may be a thermo-adhesive fiber in which a thermoplastic resin having a melting point equal to or lower than that of the component A is exposed on the fiber surface, in which case the other fiber is the split type composite fiber A When forming the bonded portion by the component by heating (that is, forming the thermal bonded portion by the A component), the thermal bonded portion is formed on the nonwoven fabric together with the A component.

  The fineness of the other fibers is not particularly limited, and may be the same as or different from the fineness of the splittable conjugate fiber. The fiber length of the other fibers is also not particularly limited, but is preferably 10 mm or more and 100 mm or less as in the case of the splittable conjugate fiber from the viewpoint of production efficiency.

(Structure of nonwoven fabric)
The nonwoven fabric of the present embodiment is a nonwoven fabric that contains split mass conjugate fibers in an amount of 20% by mass or more, and the fibers are bonded to each other by the A component of the split conjugate fibers to form an adhesive portion. The bonding portion is preferably a thermal bonding portion formed by melting or softening the component A by heating, but the bonding portion may be formed by irradiation with an electron beam or the like, or by ultrasonic welding. . The splittable conjugate fiber is as described above, and preferably has no heat splitting property.

  When the proportion of the splittable conjugate fiber in the nonwoven fabric is 20% by mass or more, the effect due to the small area and volume of the bonded portion formed by the component A, that is, the soft touch can be sufficiently secured. When the proportion of the splittable conjugate fiber is less than 20% by mass, the number of bonded portions is reduced and the strength of the nonwoven fabric is reduced, or the number of bonded portions is reduced and the nonwoven fabric surface becomes fluffy. Or the need to use other adhesive fibers, especially heat-adhesive fibers, or adhesives to ensure the strength of the nonwoven fabric, which may make the nonwoven feel hard. The proportion occupied by the splittable conjugate fibers is preferably at least 50% by mass, more preferably at least 80% by mass. Alternatively, the nonwoven fabric may be composed of only splittable conjugate fibers.

  The component A is one component of the splittable conjugate fiber, and is dispersed in the splittable conjugate fiber as a section corresponding to the number of splits. Therefore, for example, the area and the volume of the adhesive part formed by the component A tend to be smaller than the adhesive part formed by the sheath component of the core-sheath composite fiber. Due to the small size of the bonding portion, the nonwoven fabric has a soft touch. The bonding part is formed at the intersection of the fibers, the contact point between the fibers, and the like.

  In the nonwoven fabric of the present embodiment, the splitting of the splittable conjugate fiber is preferably suppressed as much as possible. Therefore, in the nonwoven fabric of the present embodiment, it is preferable that the fibers are not entangled by a mechanical entanglement treatment. The mechanical confounding process is, for example, a needle punching process and a high-pressure fluid flow process (the fluid is, for example, water, air, or steam). These treatments promote the division of the splittable conjugate fiber, generate extra-fine fibers, and also promote the entanglement of the extra-fine fibers, so that the nonwoven fabric subjected to these treatments becomes dense and bulky. May be smaller.

  The splitting of the splittable conjugate fiber may be promoted by applying pressure to the fiber or stretching the fiber in addition to the mechanical entanglement treatment. Therefore, it is preferable that the nonwoven fabric of the present embodiment is not subjected to the pressure treatment or the stretching treatment after the formation of the fibrous web. The stretching process is a process performed using a pair of gear rolls, for example, as described in JP-A-2012-67426.

  The nonwoven fabric of the present embodiment is preferably one in which a heat bonded portion is formed as a bonded portion by the A component by a hot air processing process of applying a hot air to the fiber web. According to the hot-air processing, the pressure applied to the fibrous web can be reduced to bond the fibers to each other, so that a nonwoven fabric in which the splitting of the splittable conjugate fiber is suppressed can be obtained. Alternatively, the bonded portion made of the component A may be formed by irradiation with an electron beam or the like or by ultrasonic welding as described above.

  In the nonwoven fabric of the present embodiment, as a result of the fact that the splitting of the splittable conjugate fiber is suppressed, an ultrafine fiber formed by splitting or peeling off one section constituting the splittable conjugate fiber is a splittable conjugate fiber. With a length of more than 30% of the fiber length of the fiber, it can be provided as a form that does not exist continuously. `` An ultrafine fiber in which one section constituting the splittable conjugate fiber is formed by splitting or peeling off '' is one of a plurality of sections constituting the splittable conjugate fiber, separated from the other sections. It refers to the ultrafine fibers formed. The fineness of the ultrafine fiber is determined according to the number of sections, the fineness of the splittable conjugate fiber, and the density of the resin constituting each section. The fineness of the ultrafine fibers is, for example, 0.05 dtex or more and 2 dtex or less, particularly 0.06 dtex or more and 1 dtex or less, and more particularly 0.10 dtex or more and 0.50 dtex or less.

  Further, such an ultrafine fiber “continuously exists with a length exceeding 30% of the fiber length of the splittable conjugate fiber” means that the fiber length as the ultrafine fiber is 30% of the fiber length of the splittable conjugate fiber. It means that it is longer than%. Therefore, in one splittable conjugate fiber, even if the ultrafine fiber is present at a certain portion at a length of 20% of the fiber length of the splittable conjugate fiber and at another portion at a length of 20%. (Total 40%), does not mean "continuously" present with a length greater than 30%. FIG. 1 is a schematic view showing a state in which an extra fine fiber is formed in a part of one split type conjugate fiber. In FIG. 1, 10 is a splittable conjugate fiber, 1 is an A component, 2 is a B component, and 4 is an ultrafine fiber formed by dividing one section made of the B component.

  In the nonwoven fabric of the present embodiment, the ultrafine fibers preferably do not continuously exist at a length exceeding 20% of the fiber length of the splittable conjugate fiber, and do not continuously exist at a length exceeding 10%. Is more preferred.

  When the ultrafine fibers are continuously present in a length exceeding 30% of the fiber length of the splittable conjugate fiber, the entire nonwoven fabric is composed of one section of ultrafine fibers or two or more sections. Many fine fibers tend to be present. Therefore, fluff is likely to occur in the nonwoven fabric, and the transparency may be reduced. In addition, when there are a lot of such ultrafine fibers and fine fibers, when the nonwoven fabric is used as a surface sheet of an absorbent article, or a sheet disposed between the surface sheet and the absorbent, the liquid permeation of the liquid is The speed is reduced and the surface in contact with the user's skin is more likely to be wetted by the liquid returning from the absorber.

  The nonwoven fabric of the present embodiment may include ultrafine fibers or fineness fibers formed by splitting splittable conjugate fibers. Alternatively, in the splittable conjugate fiber, a peeled portion between sections (observed as a fissure, a streak-like deep cut, or a fiber swelling when the surface of the nonwoven fabric is enlarged by about 300 times with an electron microscope) is partially generated. May be. They are mainly caused by the forces applied during fiber production or during the production of the fibrous web. The nonwoven fabric of the present embodiment does not permit the generation of such ultrafine fibers or the separation between sections, but it is desirable that the generation thereof be suppressed as much as possible.

  In the nonwoven fabric described above, a film-like pressure-bonded portion may be further partially formed. The film-like crimped portion is a portion in which the A component bonds the fibers with each other in a state where the gap between the fibers is filled, and the thickness of the non-woven fabric is smaller in the crimped portion than in the non-compressed portion. It is the part that is. The press-bonded portion is formed by expanding the fibers constituting the nonwoven fabric by, for example, the action of only pressure, or the action of heat and pressure of any one of electron beams and ultrasonic waves, particularly the action of heat and pressure. . In the film-like pressure-bonded portion, the film formed by the component A may be partially interrupted, and in the portion where the film is interrupted, the gap between the fibers is maintained as it is. By forming the pressure-bonded portion, the strength of the nonwoven fabric can be improved. The crimping portion is preferably a thermocompression bonding portion formed by the action of heat and pressure.

  Since the pressure-bonded portion is generally formed by applying pressure, the degree of division of the splittable conjugate fiber in the portion is higher than that in the non-pressure-bonded portion, and more ultrafine fibers and fineness fibers are formed. More peeling off. Therefore, the press-bonded portion is a region clearly distinguished from the non-press-bonded portion due to a reduction in the fiber gap due to the formation of the film, irregular reflection of light by extra-fine fibers, and the like. That is, when forming a partially crimped portion on the nonwoven fabric of the present embodiment, in addition to the non-crimped portion having high transparency as described later, the opacity at the crimped portion due to the division of the splittable conjugate fiber. For example, a crimped portion that is clearer and more visible is provided as compared with a nonwoven fabric made of a core-sheath composite fiber, for example. Therefore, by appropriately selecting the shape and the like of the crimping portion, an excellent design effect can be imparted to the nonwoven fabric.

  The press-bonded portion is formed by the “pressing treatment” that promotes the division of the splittable conjugate fiber described above. In that sense, the nonwoven fabric of the present embodiment in which the press-bonded portion is formed is a split-type composite. It can be said that a treatment for promoting fiber division has been performed. However, before forming the crimping portion, if a process such as pressurizing treatment that promotes the splitting of the splittable conjugate fiber is not performed, the boundary between the crimping portion and the non-crimping portion becomes clearer. It is preferable that the non-compression-bonded portion of the nonwoven fabric on which the portion is formed has not been subjected to a treatment for promoting splitting of the splittable conjugate fiber after forming the fibrous web.

The pressure-bonded portion is formed so as to occupy preferably 2% or more and 50% or less, more preferably 5% or more and 40% or less, particularly preferably 7% or more and 30% or less of the area of the nonwoven fabric. If the proportion occupied by the crimped portion is large, the feel of the nonwoven fabric may be hard. The crimping part may be provided with a geometric figure regularly, such as a dot, or may be provided irregularly. Alternatively, the crimping portion may be formed as a drawing of an animal, a character, a flower, or the like. When providing a plurality of pressure-bonding parts regularly, the area of one of the crimping portion, preferably 0.5mm ² ~320mm ^2, more preferably 0.6mm ² ~180mm ^2, particularly preferably 0.7mm ² ~80mm ² It is.

The basis weight of the nonwoven fabric of the present embodiment is not particularly limited, and is appropriately selected according to its use and the like. Basis weight of the nonwoven fabric of the present embodiment, for example, 5g / m ² ~150g / m may be ^2, preferably ^{10g / m 2 ~70g / m 2} , more preferably ^{10g / m 2 ~55g / m 2} , particularly preferably ^{12g / m 2 ~30g / m 2} , most preferably from ^{15g / m 2 ~25g / m 2} . When the basis weight of the nonwoven fabric is within this range, a soft touch can be easily obtained. Further, as the basis weight of the nonwoven fabric is smaller, higher transparency can be obtained in addition to flexibility.

Alternatively, the basis weight of the nonwoven fabric of the present embodiment, for example, 5g / m ² ~60g / m may be ^2, preferably ^{10g / m 2 ~45g / m 2} , more preferably from 10g / m ² ~40g / m ^2, particularly preferably 12 g / m ² to 30 g / m ^2, most preferably from ^{15g / m 2 ~25g / m 2} . When the basis weight of the nonwoven fabric is in this range, a highly transparent nonwoven fabric can be obtained. Further, the smaller the basis weight of the nonwoven fabric, the higher the transparency can be obtained.

The specific volume of the nonwoven fabric of the present embodiment is not particularly limited, and is appropriately selected according to its use and the like. Specific volume of the nonwoven fabric of the present embodiment, for example, be a 10cm ³ / g~100cm ³ / g, preferably 20cm ³ / g~80cm ³ / g, more preferably 30cm ³ / g~70cm ³ / g , particularly preferably 45cm ³ / g~65cm ³ / g. The specific volume can be determined from the basis weight and the thickness of the nonwoven fabric, where the thickness of the nonwoven fabric is measured with a load of 2.94 cN applied per 1 cm ² of the sample. The smaller the specific volume of the nonwoven fabric, the higher the transparency can be obtained. However, the specific volume of the nonwoven fabric may change due to the pressure applied during storage of the nonwoven fabric.

  When the nonwoven fabric of the present embodiment includes a splittable conjugate fiber composed of two components of the A component and the B component, the nonwoven fabric includes a core-sheath conjugate fiber composed of the A component and the B component (A: sheath, B: core). Also show high transparency. Although the reason is not clear, there is a possibility that a small-sized bonded portion and light refraction caused by the composite structure of the splittable composite fibers are involved.

The transparency of the nonwoven fabric of the present embodiment is determined, for example, by calculating the whiteness calculated from the data (Y, x, y) of the color difference reference value measured using a color difference meter, or dividing the whiteness by the basis weight. Is evaluated by the whiteness per unit weight obtained by the above method, the lightness L ^* measured by a colorimeter, or the lightness per unit weight L ^* obtained by dividing the L ^* by the unit weight. The whiteness and lightness are determined by a method described later.

Nonwoven fabric of the present embodiment, the basis weight is 10g / m ² ~45g / m ² about, and when not having a crimping portion is preferably whiteness of 10 to 35, more preferably whiteness of 12 to 25 . Alternatively, the nonwoven fabric of the present embodiment has a whiteness per unit area of preferably from 0.5 to 1.35, more preferably from 0.7 to 1.25, without the crimping portion. Alternatively, the nonwoven fabric of the present embodiment, in a state having no crimp portion, when the basis weight is ^{2 ~45g} / m ² approximately 10 g / m preferably has a brightness of 20 to 55, more preferably 30 to 45. Alternatively, the lightness per unit area of the nonwoven fabric of the present embodiment having no crimped portion is preferably 1 to 2.5, more preferably 1.2 to 2.3.

In the nonwoven fabric of the present embodiment, the smaller the basis weight, the higher the transparency of the nonwoven fabric. That is, the basis weight is about 12 g / m ^{2 to} 30 g / m ² , and when there is no crimping portion, the whiteness is preferably 10 to 27, more preferably 15 to 24. Alternatively, the nonwoven fabric of the present embodiment has a whiteness per unit area of preferably 0.5 to 1.3, and more preferably 0.8 to 1.2, without the crimping portion. Alternatively, the nonwoven fabric of the present embodiment, in a state having no crimp portion, when the basis weight is the 12g / m ² ~30g / m ² about preferably 20 to 46, more preferably lightness of 30 to 44. Alternatively, the lightness per unit area of the nonwoven fabric of the present embodiment having no crimped portion is preferably 1.6 to 2.3, and more preferably 1.8 to 2.25. The nonwoven fabric of the present embodiment is, for example, to improve the tactile sensation of a film or paper on which a graphic such as a character or an animal is printed, or to protect the film or paper, etc., as covering the surface of the film or paper. May be used. In that case, the nonwoven fabric of the present embodiment can impart a good touch to a film or the like, or provide protection, and also allow the drawing to be visually recognized well.

  The flexibility (draping property) of the nonwoven fabric of the present embodiment can be evaluated by, for example, a value obtained by dividing the sum of the bristles measured using a handle ometer by the basis weight, that is, the bristles per unit area. . The method of measuring the bending resistance measured using the handle ometer is as described later. The total softness per unit weight of the nonwoven fabric of this embodiment is preferably 0.5 to 2.2, more preferably 0.8 to 2.0, and particularly preferably 1. 0 to 1.8. The nonwoven fabric having such a rigidity per unit weight is soft and has excellent followability to the bent portion when used by being applied to the bent portion.

  The nonwoven fabric of the present embodiment can also be obtained as one having high lateral flexibility. Specifically, in the nonwoven fabric of the present embodiment, the sum of the softness in the longitudinal direction / the sum of the softness in the horizontal direction is preferably 2.1 to 3.5, and more preferably 2.1 to 3.5. 2.0, particularly preferably 2.2 to 2.8. When the sum total of the bending stiffness in the vertical direction / the total sum of the bending stiffness in the horizontal direction is within this range, it is easier to bend when bending along a direction parallel to the vertical direction, and it is required to be easy to bend in a specific direction. Suitable for use in various applications. Here, the longitudinal softness refers to the easiness of bending the nonwoven fabric when it is bent in a direction perpendicular to the longitudinal direction, and the transverse softness refers to the nonwoven fabric perpendicular to the transverse direction. Refers to the ease of bending when bent in the direction.

  When the nonwoven fabric of the present embodiment is used in direct or indirect contact with the absorbent in the absorbent article, the nonwoven fabric passes a liquid (eg, menstrual blood, urine, stool, or vaginal discharge) to the absorbent. It can be absorbed, and effectively prevents the liquid absorbed by the absorber from returning to the nonwoven fabric side (wet back). In particular, the nonwoven fabric of the present embodiment effectively prevents the liquid absorbed after the second time, particularly the second and third times, from returning to the nonwoven fabric side when the liquid is absorbed into the absorber in a plurality of times. it can. Therefore, when the nonwoven fabric of the present embodiment is used as a surface sheet of an absorbent article, or a sheet disposed between the surface sheet and the absorber, the surface in contact with the user's skin returns from the absorber. It can be made less likely to be wetted by the coming liquid, and can give the user a comfortable feeling of use.

(Method of manufacturing nonwoven fabric)
The nonwoven fabric of the present embodiment is
Producing a fibrous web containing at least 20% by mass of splittable conjugate fiber. Hot air processing is performed on the fibrous web to apply hot air at a temperature at which the lowest melting point component among the components constituting the splittable conjugate fiber softens or melts. A manufacturing method comprising:
Without subjecting the fibrous web to mechanical entanglement,
It can be manufactured by a manufacturing method in which the hot air processing is performed without applying a linear pressure of 10 kg / cm or more to the fiber web.

  The fibrous web can be produced by a known method. The form of the fiber web may be any form of a card web such as a parallel web, a cross web, a semi-random web and a random web, an air-lay web, and a wet papermaking web. From the viewpoint of suppressing the splitting of the splittable conjugate fiber, it is preferable to use a card web to which an external force is hardly applied during manufacturing.

  The obtained fiber web is subjected to hot-air processing so that a heat-bonded portion is formed by the component having the lowest melting point (component A) among the components constituting the splittable conjugate fiber. According to the hot-air processing, since the external force applied to the fiber web during the heat treatment can be reduced, the splitting of the splittable conjugate fiber during the heat treatment does not easily progress. The hot air processing may be performed using a device that blows hot air at a predetermined temperature onto the fiber web, for example, a hot air penetration heat treatment machine and a hot air blowing heat treatment machine. Alternatively, a heat treatment using infrared rays may be performed instead of the hot air processing. Heat treatment by infrared rays is also preferably used because an external force is hardly applied to the fiber web.

  In any case, the heat treatment is preferably performed without applying a linear pressure of 10 kg / cm or more to the fiber web. When pressure is applied during the heat treatment, the splitting of the splittable conjugate fiber is promoted, and a nonwoven fabric having desired flexibility, bulkiness and transparency may not be obtained. For example, in the hot air processing, a mesh or the like may be arranged on the fiber web for the purpose of preventing the fiber web from being turned up or adjusting the shape of the nonwoven fabric after the heat treatment. The mesh or the like is appropriately selected so that the linear pressure is not applied.

The temperature at the time of the hot air processing is appropriately selected so that the component A of the splittable conjugate fiber is softened or melted, thereby forming a heat bonded portion. For example, the melting point of component A is taken as T _A ° C., may be selected at (T _A) ° C. or higher temperatures, a temperature below the melting point of the other components of the splittable conjugate fiber. Specifically, when the component A is, for example, high-density polyethylene, hot air having a temperature of 130C to 150C may be blown.

  When manufacturing a nonwoven fabric, no mechanical entanglement treatment is performed. This is to prevent the splitting of the splittable conjugate fiber from proceeding due to the force applied during the mechanical entanglement process. The mechanical confounding process is, for example, a needle punching process and a high-pressure fluid flow process. Therefore, according to this manufacturing method, a nonwoven fabric in which fibers are integrated only by thermal bonding can be obtained.

The method for manufacturing a nonwoven fabric of the present embodiment may further include forming a thermocompression-bonded portion partially. The thermocompression bonding portion can be formed by, for example, thermo roll processing using an emboss roll. Formation of thermocompression bonded portions, for example, the temperature of the embossing roll _(T A -50) ° C. or higher _(T A +30) ° C. or less _{(T A} melting point of component A) is set to, for 10kg / cm~150kg / cm It may be performed by applying a linear pressure. The shape of the embossing roll is appropriately selected according to the shape to be formed as the thermocompression bonding portion. As described above, in the thermocompression bonding section, since pressure is applied, the division of the splittable conjugate fiber proceeds, and the degree of division becomes higher than that in the non-thermocompression bonding section. The transparency is lower than that.

(Application)
The nonwoven fabric of the present embodiment can be used for various applications, and can be used alone or in combination with paper, other nonwoven fabrics, films or sheets, for example, baby diapers, adult paper diapers, sanitary napkins, vaginal absorbent sheets ( Panty liners), surface materials of various hygiene articles such as incontinence pads, sheets disposed between the surface materials and the absorber, sheets for absorbent articles such as back materials, skin covering sheets (face masks, sticking) Base cloth), personal wipers (sweat wipe sheet, makeup remover sheet, etc.), various animal wiping sheets, and the like.

  When the nonwoven fabric of the present embodiment is used as a surface material of an absorbent article or a sheet disposed between the surface material and the absorber, as described above, especially when the liquid is absorbed for the second time, Return does not easily occur, and a comfortable feeling of use can be given to the user. Further, the back material for a sanitary article using the nonwoven fabric of the present embodiment may have a form in which the nonwoven fabric of the present embodiment is disposed on the surface of a liquid-impermeable sheet. In this case, since the nonwoven fabric of the present embodiment has high transparency, when the design is printed on the liquid impermeable sheet, the design is satisfactorily visually recognized.

Hereinafter, the present embodiment will be described with reference to examples.
The following fibers were prepared as fibers used in this example.
[Split type composite fiber 1]
It consists of a combination of polyethylene terephthalate (melting point 255 ° C) / high-density polyethylene (melting point 130 ° C) with a fineness of 2.2 dtex, a fiber diameter of 16 µm and a fiber length of 51 mm. Type composite fiber (volume ratio: 50:50 (polyethylene terephthalate: high-density polyethylene)) having a cross section arranged in a section and having a total number of sections of 8 (trade name: DFS (SH) manufactured by Daiwabo Polytech Co., Ltd.) )

[Core-sheath type composite fiber 1]
Core-sheath type composite fiber (core: polypropylene, sheath: high-density polyethylene, volume: 1.6 dtex, fiber diameter 16 μm, fiber length 51 mm, made of a combination of polypropylene (melting point 167 ° C.) / High-density polyethylene (melting point 130 ° C.) Ratio 65:35 (core: sheath)) (trade name: NBF (H) manufactured by Daiwabo Polytech Co., Ltd.)
[Core-sheath composite fiber 2]
Eccentric core-sheath composite composed of a combination of polyethylene terephthalate (melting point: 255 ° C) / high-density polyethylene (melting point: 130 ° C) with a fineness of 3.3 dtex, a fiber diameter of 21 µm, and a fiber length of 51 mm, with an eccentricity of the core component of 25% Fiber (core: polyethylene terephthalate, sheath: high-density polyethylene, volume ratio 64:36 (core: sheath))) (trade name: NBF (SH) V, manufactured by Daiwabo Polytech Co., Ltd.)
The eccentricity was determined based on the following equation.

(Example 1)
Using only the splittable conjugate fiber 1 to which the primary hydrophilic fiber treating agent was attached, a parallel web was produced using a parallel card machine at a web target weight of 20 g / m ² . The fibrous web was subjected to a heat treatment for 15 seconds by a hot air penetration type heat treatment machine set at a temperature of 135 ° C. to form a heat-bonded portion with polyethylene of the splittable composite fiber 1 to obtain a nonwoven fabric. The term "primary hydrophilic fiber treating agent" refers to a treating agent that imparts a property of significantly reducing hydrophilicity to fibers after being once contacted with water.

(Example 2)
Using only the splittable conjugate fiber 1 to which the durable hydrophilic fiber treating agent was adhered, a parallel card machine was used to produce a parallel web with a web target weight of 50 g / m ² . This fibrous web was heat-treated for 15 seconds by a hot air penetration type heat treatment machine set at a temperature of 135 ° C. to form a heat-bonded portion with polyethylene of the splittable composite fiber 1, a basis weight of 51.3 g / m ² , and a thickness of 2 A non-woven fabric of 0.74 mm was obtained.

(Example 3)
Using only a splittable conjugate fiber 1 to which a fiber treatment agent having a degree of hydrophilicity smaller than that used in Example 2 was applied, a parallel card machine was used to cut a parallel web at a web aiming weight of 50 g / m ^2. Produced. The fibrous web was heat-treated for 15 seconds by a hot air penetration type heat treatment machine set at a temperature of 135 ° C. to form a heat-bonded portion with polyethylene of the splittable composite fiber 2, having a basis weight of 52.4 g / m ² and a thickness of 2 A nonwoven fabric of .86 mm was obtained.

(Example 4-1)
A parallel web was prepared using a parallel card machine with a web aiming weight of 50 g / m ² , using 20% by mass of the splittable conjugate fiber 1 and 80% by mass of the core / sheath conjugate fiber 2. In this example, the splittable conjugate fiber 1 and the core-sheath conjugate fiber 2 were both used by adhering a durable hydrophilic fiber treating agent. This fibrous web is heat-treated for 15 seconds by a hot air penetration type heat treatment machine set at a temperature of 135 ° C. to form a heat-bonded portion with polyethylene of the split type composite fiber 1 and the core-sheath type composite fiber 2, and a basis weight of 48.7 g. / M ² and a non-woven fabric having a thickness of 4.23 mm.

(Example 4-2)
A parallel web was prepared using a parallel card machine with a web aiming weight of 50 g / m ² , using 20% by mass of the splittable conjugate fiber 1 and 80% by mass of the core / sheath conjugate fiber 2. In this example, both the splittable conjugate fiber 1 and the core / sheath conjugate fiber 2 were used by adhering a durable hydrophilic fiber treatment agent. The fibrous web was heat-treated for 15 seconds by a hot air penetration type heat treatment machine set at a temperature of 135 ° C. to form a heat-bonded portion with polyethylene of the split type composite fiber 1 and the core-sheath type composite fiber 2, and the basis weight was 49.9 g. / M ² and a non-woven fabric having a thickness of 4.43 mm.

(Comparative Example 1)
Using only the core-sheath type composite fiber 1, a nonwoven fabric having a heat-bonded portion formed by a sheath portion was produced in the same procedure as that used in Example 1. The core-sheath type composite fiber 1 was used with a primary hydrophilic fiber treatment agent attached thereto. The basis weight of the obtained nonwoven fabric was 20.3 g / m ² , and the thickness was 2.07 mm.

(Comparative Example 2-1)
Using only the core-sheath type composite fiber 2, a nonwoven fabric having a heat-bonded portion formed by a sheath portion was produced in the same procedure as that employed in Example 2. The core-sheath type composite fiber 2 was used by attaching a durable hydrophilic fiber treatment agent. The basis weight of the obtained nonwoven fabric was 44.1 g / m ² , and the thickness was 4.24 mm.

(Comparative Example 2-2)
Using only the core-sheath type composite fiber 2, a nonwoven fabric having a heat-bonded portion formed by a sheath portion was produced in the same procedure as that employed in Example 2. The core-sheath type composite fiber 2 was used by attaching a durable hydrophilic fiber treatment agent. The basis weight of the obtained nonwoven fabric was 48.1 g / m ² , and the thickness was 4.82 mm.

[Eye weight, thickness, specific volume, flexibility]
Table 1 shows the basis weight, thickness (thickness of the non-thermocompression-bonded portion), and the specific volume of Example 1 and Comparative Example 1, and shows the basis weight and thickness (non-thermal thickness) of Example 4-1 and Comparative Example 2-1. Table 2 shows the thickness of the pressure-bonded portion) and the specific volume. Further, Table 1 also shows the results of evaluating the flexibility of Example 1 and Comparative Example 1, and Table 2 also shows the results of evaluating the flexibility of Example 4-1 and Comparative Example 2-1.
The thickness of the nonwoven fabric was measured using a thickness measuring machine (trade name: THICKNESS GAUGE model CR-60A, manufactured by Daiei Kagaku Seiki Seisaku-sho, Ltd.) while applying a load of 2.94 cN per 1 cm ^{2 of} the sample.

The drapability (softness) of the nonwoven fabric was measured according to JIS L 1096 6.19.5 E method (handle ometer method). Specifically, the measurement was performed according to the following procedure.
A test piece having a length of 20 cm and a width of 20 cm is placed on a sample table so that the measurement direction of the test piece is perpendicular to the slot (gap width 10 mm).
Next, the blade of the penetrator adjusted so as to be lowered to 8 mm from the surface of the sample table is lowered, and when the test piece is pushed in, 6.7 cm (1/3 of the width of the test piece) from either side. At each position, the resistance value against the indentation is read at different positions in the vertical and horizontal directions. The highest value (g) indicated by the microammeter is read as the resistance value.
The measurement is performed in a direction parallel to the MD direction (also referred to as a machine direction or a longitudinal direction) and a direction parallel to the CD direction (also referred to as a width direction or a transverse direction) of the nonwoven fabric. And then measured at two different points in a direction parallel to the MD direction.
The measurement is performed three times at each measurement point, and the average value is defined as the bending resistance of each measurement point (MD-1, MD-2, CD-1, CD-2), and the sum of these is divided by the basis weight. The value obtained by dividing the sum of the bending stiffness in the MD direction by the sum of the bending stiffness in the MD direction and the sum of the bending stiffness in the CD direction is evaluated as drapability. In the table, MD-1 and MD-2 are values measured by placing the sample on the sample table so that the longitudinal direction of the sample is orthogonal to the length direction of the slot. CD-1 and CD-2 are the values of the sample. Is a value measured by placing a sample on a sample table such that the lateral direction of the sample is orthogonal to the length direction of the slot.

[Whiteness, brightness]
Example 1 and Comparative Example 1 were evaluated for whiteness and whiteness per unit area, and lightness and lightness per unit area. Table 3 shows the evaluation results. The whiteness and lightness were evaluated by the following methods.
(Whiteness)
The sample whose basis weight was measured in advance was cut into a size of 30 cm (MD direction) × 21 cm (CD direction) and placed on a black cloth. In this state, the data (Y, x, y) value (Y: reflectance, xy: chromaticity) of the color difference reference value was measured using a colorimeter (CR-310 manufactured by Minolta Camera Co., Ltd.). . The color difference meter used displayed data values when three points were measured. For each sample, the data value is displayed twice (measurement of the data value is performed twice), the whiteness is calculated from each data value by the following formula, and the average value is calculated as the whiteness of the sample. did. Further, the whiteness was divided by the basis weight to determine the whiteness per basis weight.

(Lightness L ^* )
The sample whose basis weight was measured in advance was cut into a size of 30 cm (MD direction) × 21 cm (CD direction), placed on a sample table, and covered with a black cap used for zero point configuration. With the cap covered, L ^* , a ^* , and b ^* were measured. The measurement was performed four times in total by performing the operation of rotating the direction of the sample 90 degrees three times, and the average value was displayed as a measurement result.

  Although Example 1 and Comparative Example 1 were composed of fibers having the same fiber diameter, Example 1 exhibited lower whiteness and lightness and higher transparency than Comparative Example 1. .

Each of the nonwoven fabrics obtained in Example 1 and Comparative Example 1 was subjected to hot roll processing using an embossing roll to form a thermocompression bonded portion. At the time of hot roll processing, an emboss roll provided with a cylindrical convex portion (emboss area of the convex portion: 0.79 mm ² ) having a diameter of 1 mm and a height of 0.5 mm was used at a temperature of 100 ° C. and a linear pressure of 20 kg /. cm. In the nonwoven fabric, the thermocompression bonding portion occupied 19.7% of the total area of the nonwoven fabric.

  Electron micrographs of the surface or the cross section of Example 1 and Comparative Example 1 are shown in FIGS. 2 and 3 (Example 1) and FIG. 5 (Comparative Example 1) are photographs of the non-thermocompression bonding surface of the nonwoven fabric surface at a magnification of 300 times. 4 (Example 1) and FIG. 6 (Comparative Example 1) show electron micrographs of the thermocompression-bonded sections of Example 1 and Comparative Example 1 taken at a magnification of 500 times.

  In each of Example 1 and Comparative Example 1, a film was formed in the thermocompression-bonded portion with the molten polyethylene. In Example 1, since the splitting of the splittable conjugate fiber was promoted in the thermocompression bonding section, it was confirmed that ultrafine fibers were formed (FIG. 4). Further, in the non-thermocompression-bonded portion of Example 1, although the exfoliated portion (split) and the formation of ultrafine fibers were observed in some of the fibers due to the division of the splittable conjugate fibers, the ultrafine fibers had a fiber length. There was no continuous occurrence exceeding 30%, and the division was suppressed as a whole (FIGS. 2 and 3). Further, in Example 1, the outline of the thermocompression bonding portion was clearer than in Comparative Example 1, and the shape of the thermocompression bonding portion could be visually recognized more clearly.

[Liquid return property]
The liquid return properties of Examples 2, 3, 4-2 and Comparative Example 2-2 were evaluated. Table 4 shows the evaluation results. The liquid return property was evaluated by the following method.
(Liquid returnability)
(1) The following articles were prepared to measure the amount of liquid returned.
Absorber (commercially available baby disposable diapers disassembled and removed)
Plate with injection cylinder (2.5cm inside diameter at bottom of cylinder)
0.9% saline (colored with blue dye)
Filter paper (ADVANTEC (registered trademark) No. 2 manufactured by Toyo Roshi Kaisha, Ltd.) 10 cm × 10 cm
Weight (5kg) 10cm x 10cm
(2) Method The liquid return amount was measured according to the following procedure.
(I) A nonwoven fabric sample (vertical 42 cm × horizontal 21 cm) is placed on the absorber, and the plate with the injection cylinder is placed thereon.
(Ii) Inject 50 ml of physiological saline warmed to about 37 ° C. from the tube. At this time, the physiological saline is left undiscovered from the surface of the nonwoven fabric (the physiological saline is no longer confirmed as a liquid).
(Iii) Remove the plate with the injection cylinder and let stand for 10 minutes.
(Iv) Ten minutes later, filter paper (30 sheets) is placed on the nonwoven fabric, and a 5 kg weight is placed on the nonwoven fabric for 20 seconds. Thereafter, the mass of the filter paper is measured (the difference between the mass of the filter paper before being placed on the nonwoven fabric and the filter paper after being placed on the nonwoven fabric and having the weight placed thereon corresponds to the amount of reversion).
(Vi) Returning to the above (i), the second measurement is performed.
With respect to the liquid return property, three samples were prepared for one sample (nonwoven fabric), and the average value of the liquid return amounts measured for each of the three samples was defined as the liquid return amount of the sample.

  In Examples 2, 3, and 4-2, the second and third liquid return amounts were smaller than Comparative Example 2-2. In Example 2 and Example 4-2, the liquid return amount in the second time was smaller than that in the first time, and in Example 3, the change in the liquid return amount between the first time and the second time was small. On the other hand, in Comparative Example 2-2, the second liquid return amount was larger than the first liquid return amount, and the third liquid return amount was the largest among the four samples.

  Since the nonwoven fabric of the present embodiment is flexible and hardly causes liquid return, it is suitably used, for example, as a constituent member of an absorbent article.

Claims (10)

A nonwoven fabric comprising splittable conjugate fibers of 20% by mass or more, wherein the fibers are bonded to each other by one component of the splittable conjugate fibers (hereinafter, “A component”) to form an adhesive portion,
The splittable conjugate fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less,
Splittable conjugate fiber, the melting point of component A is taken as T _A ° C., when heated for 60 seconds at T A _-5 ° C., all SANYO nonthermal splittable peeling does not occur between the sections,
The fineness of the splittable conjugate fiber is 1.5 dtex or more and 2.5 dtex or less,
The sum of the bristles per unit weight of the nonwoven fabric is 0.5 to 2.2,
Non-woven fabric. The split type conjugate fiber contains 20% by mass or more, and the fibers are adhered to each other by one component of the split type conjugate fiber (hereinafter, referred to as “component A”) to form an adhesive portion, and the film-like crimped portion is partially A non-woven fabric,
The splittable conjugate fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less,
Splittable conjugate fiber, the melting point of component A is taken as T _A ° C., when heated for 60 seconds at T A _-5 ° C., are of non-thermal splitting may not occur delamination between the sections,
The degree of splitting of the splittable conjugate fiber in the crimped portion is much larger than the degree of splitting of the split type conjugated fiber portion other than the bonding portion,
The fineness of the splittable conjugate fiber is 1.5 dtex or more and 2.5 dtex or less,
Non-woven fabric. A nonwoven fabric comprising splittable conjugate fibers of 20% by mass or more, wherein the fibers are bonded to each other by one component of the splittable conjugate fibers (hereinafter, “A component”) to form an adhesive portion,
The splittable conjugate fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less,
Microfibers one section of the plurality of sections constituting the splittable conjugate fiber is split or peeled to formation, he in fiber length 30% greater than the length of the splittable conjugate fiber was continuously present Without
The fineness of the splittable conjugate fiber is 1.5 dtex or more and 2.5 dtex or less,
The sum of the bristles per unit weight of the nonwoven fabric is 0.5 to 2.2,
Non-woven fabric. The split type conjugate fiber contains 20% by mass or more, and the fibers are adhered to each other by one component of the split type conjugate fiber (hereinafter, referred to as “component A”) to form an adhesive portion, and the film-like crimped portion is partially A non-woven fabric,
The splittable conjugate fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less,
The degree of division of the splittable conjugate fiber in the crimped portion is larger than the degree of division of the splittable conjugate fiber in a portion other than the crimped portion,
In a portion other than the crimping portion, the ultrafine fiber formed by splitting or peeling one of the plurality of sections constituting the splittable conjugate fiber has a length exceeding 30% of the fiber length of the splittable conjugate fiber. Does not exist continuously,
The fineness of the splittable conjugate fiber is 1.5 dtex or more and 2.5 dtex or less,
Non-woven fabric.   The nonwoven fabric according to any one of claims 1 to 4, wherein the component A is a high-density polyethylene. Nonwoven fabric according to claim 1, basis weight is 10 g / m ² or more 55 g / m ² or less.
Non-woven fabric. Producing a fibrous web containing a splittable conjugate fiber having a fineness of not less than 1.5 dtex and not more than 2.5 dtex by 20% by mass or more, wherein the component having the lowest melting point among the components constituting the splittable conjugate fiber is softened or Including performing hot air processing to apply hot air at a temperature to melt,
Without subjecting the fibrous web to mechanical entanglement,
The hot-air processing is performed without applying a linear pressure of 10 kg / cm or more to the fibrous web and in such a manner that the total softness per unit weight of the nonwoven fabric is 0.5 to 2.2 . Production method.   The manufacturing method according to claim 7, further comprising partially forming a thermocompression bonding portion.   A sheet for an absorbent article, comprising the nonwoven fabric according to any one of claims 1 to 6.   The sheet for an absorbent article according to claim 9, which is a surface material or a sheet disposed between the surface material and the absorber.