JP7021418B2 - Nonwoven fabric and its manufacturing method, as well as sheets for absorbent articles - Google Patents

Description

The present disclosure relates to a nonwoven fabric using a split type composite fiber, a method for producing the same, and a sheet for an absorbent article.

Various non-woven fabrics using split-type composite fibers that can be divided into a plurality of components by an external force have been proposed. The split type composite fiber behaves like a single fiber at the stage of producing the fiber web, and after the fiber web is produced, a division process of physically applying pressure to divide the fiber into each component, for example, a high-pressure water flow 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. Non-woven fabrics containing ultrafine fibers can be used as sanitary goods (for example, sanitary products, disposable diapers), wipers, base cloths for artificial leather, etc. by utilizing their soft touch, fineness, and good wiping property of ultrafine fibers. It is used. For example, Patent Document 1 describes a non-woven fabric obtained by dividing a split-type composite fiber by using a high-pressure water flow treatment.

Further, as the split type composite fiber, a heat split type composite fiber in which one of the constituent components is formed of a resin having a higher heat shrinkage property and which can be split by heat treatment has also been proposed. A non-woven fabric constructed by using such a heat-split type composite fiber is proposed in Patent Document 2. Patent Document 2 discloses a non-woven fabric having excellent tactile sensation and dust collecting ability, which is obtained by dividing a heat-splitting composite fiber by heat treatment and pressure treatment.

Japanese Unexamined Patent Publication No. 8-260316 Japanese Unexamined Patent Publication No. 9-273061

The present embodiment is made for the purpose of suppressing the division of the split type composite fiber to provide a flexible nonwoven fabric.

In one gist of the present disclosure, a non-woven fabric containing 20% by mass or more of split-type composite fibers and the fibers are bonded to each other by one component of the split-type composite fibers (hereinafter, “component A”) to form an adhesive portion. And,
The split type composite fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less.
The split-type composite fiber is a non-thermally splitable fiber in which peeling between sections does not occur when the component _A is heated at TA-5 ° C for 60 seconds when the melting point of the component _A is TA ° C.
Provide non-woven fabric.

In another gist of the present disclosure, a non-woven fabric containing 20% by mass or more of split-type composite fibers and the fibers are bonded to each other by one component of the split-type composite fibers (hereinafter referred to as “component A”) to form an adhesive portion. And,
The split type composite fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less.
The ultrafine fibers formed by splitting or peeling one of the multiple sections constituting the split-type composite fiber do not continuously exist in a length exceeding 30% of the fiber length of the split-type composite fiber. ,
Provide non-woven fabric.

This disclosure is in yet another gist.
Producing a fiber web containing 20% by mass or more of split-type composite fibers A hot air processing process is performed on the fiber web by applying hot air at a temperature at which the component having the lowest melting point among the components constituting the split-type composite fiber softens or melts. Including doing
The fiber web is not mechanically entangled,
Provided is a method for producing a nonwoven fabric, in which a hot air processing treatment is performed without applying a linear pressure of 10 kg / cm or more to the fiber web.

The nonwoven fabric of the present embodiment has a soft tactile sensation because the division of the split-type composite fiber is suppressed and the adhesive portion is formed by melting or softening the components of the small sections constituting the split-type composite fiber. ..

FIG. 1 is a perspective view showing a state in which ultrafine fibers are formed in a part of split type composite fibers. 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.

(Background to this embodiment)
In general, split-type composite fibers are used for producing fabrics such as non-woven fabrics containing ultrafine fibers by utilizing the property of splitting into a plurality of components by an external force or a heat shrinkage force of a constituent component. However, by not actively dividing the split-type composite fiber, the present inventors can take advantage of the structure of the split-type composite fiber in which a plurality of small sections are assembled, and have an unprecedented tactile sensation or characteristic. I thought that a non-woven fabric could be obtained. Therefore, a split-type composite fiber that can be split by an external force but does not exhibit thermal splitability is used, and a heat-bonding treatment is performed by hot air processing so that the split is unlikely to occur to produce a heat-bonded nonwoven fabric. As a result, it was found that a flexible non-woven fabric can be obtained. Furthermore, the present inventors have found that the heat-bonded nonwoven fabric produced by using the split-type composite fiber has higher transparency than the heat-bonded nonwoven fabric produced by using the core-sheath type composite fiber.
Hereinafter, the nonwoven fabric of the present embodiment will be described.

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

In the present embodiment, as the split type composite fiber, one having no heat splittability is preferably used. Specifically, when the melting point of the component constituting the split-type composite fiber, which has the lowest melting point and forms the adhesive portion in the nonwoven fabric (hereinafter referred to as “component _A ”), is set to TA ° C., _TA . Split-type composite fibers that do not cause separation between sections when heated at −5 ° C. for 60 seconds are preferably used. In the peeling between the sections, one section of the plurality of sections constituting the split type composite fiber is peeled or separated to form ultrafine fibers on the side surface of the fiber after heating at TA _- 5 ° C. for 60 seconds. It is judged that it has occurred. When peeling occurs between sections in the split type composite fiber due to the application of mechanical force, peeling between new sections does not occur when heated at TA _- 5 ° C for 60 seconds. Also, in the present embodiment, a split type composite fiber having no heat splittability is preferably used. When a split-type composite fiber having no thermal splittability is used, the split-type composite fiber does not proceed to be split when subjected to hot air processing, and the formation of ultrafine fibers is suppressed, so that many ultrafine fibers are formed. It is possible to obtain a non-woven fabric having a high transparency (transparency) as compared with the non-woven fabric. Further, when the nonwoven fabric containing such a split type composite fiber is used as a surface sheet of an absorbent article or a sheet arranged between the surface sheet and the absorber, it is formed by dividing the split type composite fiber. The liquid permeation rate of the liquid is higher than that of the non-woven fabric containing a large amount of ultrafine fibers, and the surface in contact with the user's skin is less likely to be wetted by the liquid returning from the absorber.

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

The components constituting the split-type composite fiber are not particularly limited, and polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and their copolymers, 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. Is arbitrarily selected from the polyethylene-based resins of the above, polyamide-based resins such as nylon 6, nylon 12, and nylon 66.

The split type composite fiber is composed of, for example, two components, the component A and a resin component (hereinafter, “component B”) having a melting point 10 ° C. or higher higher than the melting point TA ° C. of the component _A. good. In that case, the combination of the components constituting the split-type composite fiber is polyethylene terephthalate / polyethylene, polypropylene / polyethylene or the like (polyethylene is any one of high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. Or a combination of them). Since polyethylene melts at a relatively low temperature and adheres the fibers well to each other, it is preferable to use this as the component A. When polyethylene is high-density polyethylene, its thermal shrinkage is compared with other thermoplastic resins polymerized with ethylene as a monomer, such as low-density polyethylene, linear low-density polyethylene, and ethylene-propylene copolymer. Since the property is small, the heat splitting property of the split type composite fiber can be reduced. Therefore, even if the split type composite fiber containing high-density polyethylene as the A component is subjected to heat treatment for thermal adhesion, the sections containing the high-density polyethylene do not undergo large heat shrinkage, and peeling between the sections is further suppressed. Therefore, it is preferable. Further, when the high melting point component to be combined with the A component is a high melting point polyester resin such as polyethylene terephthalate, when the A component is polyethylene, the temperature difference between the melting points and the polyethylene is large, so that the heat bonding treatment is performed. It is preferable because the bulk does not easily settle even if the above is performed. In addition, polyester resins such as polyethylene terephthalate have a high elastic modulus of the resin itself, and the split-type composite fiber and the non-woven fabric containing the same have "stiffness", which makes it easy to increase the bulkiness of the non-woven fabric, which is preferable.

The fineness of the split type composite fiber is preferably 0.6 dtex or more and 6 dtex or less, more preferably 0.8 dtex or more and 4.8 dtex or less, still more preferably 1.2 dtex or more and 3.5 dtex or less, and most preferably. Is 1.5 dtex or more and 2.5 dtex or less.
Further, the number of sections in the split type composite fiber (that is, the number of divisions into each component in the split type composite fiber) is preferably, for example, 4 or more and 32 or less, and 4 or more and 20 or less. Is more preferable, and 6 or more and 16 or less are most preferable. When the split type composite fiber is composed of two components, A component and 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 preferable.

If the number of sections is small, the area and volume per section may be large, the area and / or volume of the bonded portion may be large, and the texture 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 split-type composite fiber itself, and the split-type composite fiber having a small fineness is manufactured. It is difficult and may reduce the productivity of the non-woven fabric. On the other hand, in the split type composite fiber having a large number of sections, the area exposed on the fiber surface per section becomes small depending on the shape of the fiber cross section. As a result, the area of the adhesive point formed by the component A also becomes small, and the tensile strength of the obtained nonwoven fabric may not be sufficient, or the surface may become fluffy. Further, such a split type composite 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 split-type composite fibers may increase the manufacturing cost of the non-woven fabric.

The shape of the section is not particularly limited. For example, the split type composite fiber may have wedge-shaped sections arranged in a chrysanthemum pattern. Alternatively, the split type composite fiber may be one in which each section is arranged in a layer in the fiber cross section. Further, the split type composite fiber may be a so-called solid split type composite fiber having no continuous cavity portion in the length direction when the fiber cross section is observed, or one or more cavities continuous in the length direction. It may be a so-called hollow split type composite fiber having a portion. From the viewpoint of suppressing division, a solid division type composite fiber is preferably used.

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

The fiber length of the split type composite fiber is 10 mm or more and 100 mm or less. Since the split type composite fiber may be split by the force applied at the time of cutting the fiber, if the fiber length is less than 10 mm, the number of ultrafine fibers formed by the split of the split type composite fiber in the nonwoven fabric increases. For example, the transparency of the non-woven fabric may decrease. Further, if the fiber length is less than 10 mm, it is difficult to obtain a bulky fiber web, and the fiber web may not be manufactured by the card method using a parallel card machine or the like. If the fiber length of the split type composite fiber exceeds 100 mm, it may be difficult to produce a fiber web using, for example, a card machine. Further, in a non-woven fabric having a low basis weight, if the fiber length exceeds 100 mm, the number of fibers constituting the non-woven fabric decreases, so that the texture of the non-woven fabric may not be stable or the required strength of the nonwoven fabric cannot be obtained. There is. The fiber length is more preferably 25 mm or more and 100 mm or less, further 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 contain fibers other than the split type composite fiber. Other fibers are not particularly limited and include, for example, natural fibers such as cotton, silk and wool, biscorayons, cupra, and solvent-spun cellulose fibers (eg, lenting lyocell® and tencel®). It may be a recycled fiber, a polyolefin fiber, a polyester fiber and a polyamide fiber, a (poly) acrylic single fiber made of acrylic nitrile, and a fiber made of engineering plastic such as polycarbonate, polyacetal, polystyrene, or cyclic polyolefin. .. Further, as other fibers, not only a single fiber made of one kind of thermoplastic resin but also a composite fiber other than a split type composite fiber made of two or more kinds of thermoplastic resins (for example, a concentric or eccentric core sheath). Type composite fiber, sea island type composite fiber, side-by-side type composite fiber) can also be used. The other fiber may be a heat-adhesive fiber in which a thermoplastic resin having the same or lower melting point as the component A is exposed on the fiber surface, in which case the other fiber is A of the split type composite fiber. When forming the adhesive portion by the component by heating (that is, forming the thermal adhesive portion by the A component), the thermal adhesive portion is formed in 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 split type composite fiber. The fiber length of the other fibers is also not particularly limited, but it is preferably 10 mm or more and 100 mm or less from the viewpoint of production efficiency, as in the case of the split type composite fiber.

(Composition of non-woven fabric)
The nonwoven fabric of the present embodiment is a nonwoven fabric containing 20% by mass or more of split-type composite fibers, and the fibers are bonded to each other by the A component of the split-type composite fibers to form an adhesive portion. The bonded portion is preferably a heat-bonded portion formed by melting or softening the component A by heating, but the bonded portion may be formed by irradiation with an electron beam or ultrasonic welding. .. The split type composite fiber is as described above, and preferably does not have thermal splittability.

When the proportion of the split type composite fiber in the nonwoven fabric is 20% by mass or more, the effect due to the small area and volume of the adhesive portion formed by the component A, that is, a flexible tactile sensation can be sufficiently ensured. When the proportion of the split type composite fiber is less than 20% by mass, the number of adhesive portions is reduced and the strength of the nonwoven fabric is reduced, or the number of bonded portions is reduced and the surface of the nonwoven fabric becomes fluffy. Or the need to use other adhesive fibers, especially thermal adhesive fibers, or adhesives to ensure the strength of the non-woven fabric may result in a stiff feel to the non-woven fabric. The proportion of the split type composite fiber is preferably 50% by mass or more, more preferably 80% by mass or more. Alternatively, the nonwoven fabric may be composed only of split type composite fibers.

The component A is one component of the split type composite fiber, and is dispersed and exists in the split type composite fiber as a section according to the number of divisions. Therefore, for example, the area and volume of the bonded portion formed by the component A tends to be smaller than that of the bonded portion formed by the sheath component of the core-sheath type composite fiber. Due to the small size of the bonded portion, the non-woven fabric has a soft tactile sensation. The adhesive portion is formed at an intersection between fibers, a contact point between fibers, and the like.

In the nonwoven fabric of the present embodiment, it is preferable that the division of the split type composite fiber is suppressed as much as possible. Therefore, in the nonwoven fabric of the present embodiment, it is preferable that the fibers are not entangled by mechanical entanglement treatment. The mechanical entanglement treatment is, for example, needle punching treatment and high pressure fluid flow treatment (the fluid is, for example, water, air, steam, etc.). These treatments promote the division of the split-type composite fibers to generate ultrafine fibers and also promote the entanglement of the ultrafine fibers. Therefore, the non-woven fabric subjected to these treatments becomes dense and bulky. May be smaller.

The division of split-type composite fibers may be facilitated by applying pressure to the fibers or by stretching the fibers, in addition to the mechanical entanglement treatment. Therefore, it is preferable that the nonwoven fabric of the present embodiment is not subjected to pressure treatment or stretching treatment after the fiber web is formed. The stretching process is, for example, a process performed using a pair of gear rolls as described in Japanese Patent Application Laid-Open No. 2012-67426.

The nonwoven fabric of the present embodiment preferably has a heat-bonded portion formed as an adhesive portion by the component A by a hot-air processing treatment in which hot air is applied to the fiber web. According to the hot air processing treatment, the pressure applied to the fiber web can be reduced to bond the fibers to each other, so that a non-woven fabric in which the division of the split type composite fiber is suppressed can be obtained. Alternatively, the adhesive portion formed by the component A may be formed by irradiation with an electron beam or ultrasonic welding or ultrasonic welding as described above.

In the nonwoven fabric of the present embodiment, as a result of the division of the split type composite fiber being suppressed, the ultrafine fibers formed by splitting or peeling off one section constituting the split type composite fiber are the split type composite fibers. It can be provided as a non-woven fabric having a length exceeding 30% of the fiber length of the fiber. What is "ultrafine fiber formed by dividing or peeling off one section constituting a split-type composite fiber"? Of the plurality of sections constituting the split-type composite fiber, one section is separated from the other sections. It refers to the ultrafine fibers that are formed. The fineness of the ultrafine fibers is determined according to the number of sections, the fineness of the split composite fiber, and the density of the resin constituting each section. The fineness of the ultrafine fiber 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 ultrafine fibers "consecutively exist at a length exceeding 30% of the fiber length of the split type composite fiber" means that the fiber length as the ultrafine fiber is 30 of the fiber length of the split type composite fiber. Refers to being longer than%. Therefore, in one split-type composite fiber, even if the ultrafine fibers are present in one portion at a length of 20% of the fiber length of the split-type composite fiber and in another portion at a length of 20%. It does not exist "continuously" with a length greater than 30% (40% total). FIG. 1 shows a schematic diagram showing a state in which ultrafine fibers are formed in a part of one split type composite fiber. In FIG. 1, 10 is a split type composite fiber, 1 is an A component, 2 is a B component, and 4 is an ultrafine fiber formed by dividing one section composed of the B component.

In the nonwoven fabric of the present embodiment, the ultrafine fibers are preferably not continuously present in a length exceeding 20% of the fiber length of the split type composite fiber, and are not continuously present in a length exceeding 10%. Is more preferable.

When the ultrafine fibers are continuously present in a length exceeding 30% of the fiber length of the split type composite fiber, the entire nonwoven fabric is composed of the ultrafine fibers consisting of one section or two or more sections. There is a tendency for a large number of fine fibers to be present. Therefore, fluffing is likely to occur in the non-woven fabric, and the transparency may be lowered. Further, when such a large amount of ultrafine fibers and fineness fibers are present, when the nonwoven fabric is used as a surface sheet of an absorbent article or a sheet arranged between the surface sheet and the absorber, a liquid permeable liquid is used. 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 dividing the split type composite fibers. Alternatively, in the split type composite fiber, a peeling portion between sections (observed as a crack, a deep streak cut, or a swelling of the fiber when the surface of the non-woven fabric is magnified about 300 times with an electron microscope) is partially generated. There may be. They are mainly caused by the forces applied during fiber production or during the production of fiber webs. The non-woven fabric of the present embodiment does not tolerate the generation of such ultrafine fibers or peeling between sections, but it is desirable that the generation thereof is suppressed as much as possible.

Further, a film-like pressure-bonding portion may be partially formed on the nonwoven fabric described above. The film-shaped crimping portion is a portion where the A component adheres the fibers to each other in a state where the gaps between the fibers are filled, and the crimping portion has a smaller thickness of the non-woven fabric than the non-crimping portion. This is the part that is used. The crimping portion is formed by expanding the fibers constituting the non-woven fabric by, for example, the action of pressure alone or the action of pressure with either heat, electron beam or 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 the gap between the fibers is maintained as it is in the portion where the film is interrupted. By forming the crimping 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 crimped portion is generally formed by applying pressure, the degree of division of the split type composite fiber is higher in the crimped portion than that in the non-crimped portion, and more ultrafine fibers and fineness fibers are formed between the sections. More peeling has occurred. Therefore, the crimped portion is a region clearly distinguished from the non-crimped portion due to the reduction of fiber gaps due to the formation of the film and the diffused reflection of light by the ultrafine fibers and the like. That is, when a partially crimped portion is formed on the nonwoven fabric of the present embodiment, the non-crimped portion has high transparency as described later, and the split type composite fiber is divided to make the crimped portion opaque. In order to increase the number of fibers, a crimping portion that is clearer and easier to see is provided as compared with a non-woven fabric made of, for example, a core-sheath type composite fiber. Therefore, the crimping portion can impart an excellent design effect to the nonwoven fabric by appropriately selecting the shape and the like.

The crimping portion is formed by the "pressurization treatment" that promotes the division of the split type composite fiber described above, and in that sense, the nonwoven fabric of the present embodiment in which the crimping portion is formed is a split type composite. It can be said that the treatment for promoting the division of the fiber has been applied. However, if a treatment for promoting the division of the split type composite fiber such as a pressure treatment is not performed before forming the crimped portion, the boundary between the crimped portion and the non-crimped portion becomes clearer, so that the crimping portion is crimped. It is preferable that the non-woven fabric in which the portion is formed is one in which the non-bonded portion is not subjected to a treatment for promoting the division of the split type composite fiber after the fiber web is formed.

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, and particularly preferably 7% or more and 30% or less of the area of the nonwoven fabric. If the ratio of the crimped portion is large, the texture of the non-woven fabric may become hard. The crimping portion may be provided with geometric figures regularly or irregularly, such as dots. Alternatively, the crimping portion may be formed as a drawing of an animal, a character, a flower, or the like. When a plurality of crimping portions are regularly provided, the area of one crimping portion is preferably 0.5 mm ² to 320 mm ² , more preferably 0.6 mm ² to 180 mm ² , and particularly preferably 0.7 mm ² to 80 mm ² . Is.

The basis weight of the nonwoven fabric of the present embodiment is not particularly limited, and is appropriately selected depending on the intended use and the like. The texture of the non-woven fabric of the present embodiment may be, for example, 5 g / m ² to 150 g / m ² , preferably 10 g / m ² to 70 g / m ² , and more preferably 10 g / m ² to 55 g / m ² . It is particularly preferably 12 g / m ² to 30 g / m ² , and most preferably 15 g / m ² to 25 g / m ² . When the basis weight of the non-woven fabric is within this range, it is easy to obtain a flexible tactile sensation. Further, the smaller the basis weight of the nonwoven fabric, the higher the transparency can be obtained in addition to the flexibility.

Alternatively, the texture of the non-woven fabric of the present embodiment may be, for example, 5 g / m ² to 60 g / m ² , preferably 10 g / m ² to 45 g / m ² , and more preferably 10 g / m ² to 40 g / m. ² , particularly preferably 12 g / m ² to 30 g / m ² , and most preferably 15 g / m ² to 25 g / m ² . When the basis weight of the nonwoven fabric is within 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 depending on the intended use and the like. The specific volume of the nonwoven fabric of the present embodiment may be, for example, 10 cm ³ / g to 100 cm ³ / g, preferably 20 cm ³ / g to 80 cm ³ / g, and more preferably 30 cm ³ / g to 70 cm ³ / g. Particularly preferably, it is 45 cm ³ / g to 65 cm ³ / g. The specific volume can be determined from the basis weight and thickness of the nonwoven fabric, and here, the thickness of the nonwoven fabric shall be measured with a load of 2.94 cN per 1 cm ² of the sample. The smaller the specific volume of the non-woven fabric, the higher the transparency can be obtained. However, the specific volume of the non-woven fabric may change due to the pressure applied during storage of the non-woven fabric.

When the nonwoven fabric of the present embodiment contains a split-type composite fiber composed of two components, A component and B component, it is more than a nonwoven fabric containing a core-sheath type composite fiber (A: sheath, B: core) composed of A component and B component. Also shows high transparency. The reason is not clear, but it may be related to the adhesive portion having a small size and the refraction of light due to the composite structure of the split type composite fiber.

The transparency of the non-woven fabric of the present embodiment is determined by, for example, the whiteness calculated from the data (Y, x, y) of the color difference reference value measured using a color difference meter, or the whiteness divided by the scale. It is evaluated by the whiteness per grain obtained by the above, the lightness L ^* measured by the color difference meter, or the lightness L ^* per grain obtained by dividing the L ^* by the grain. Whiteness and lightness are determined by the method described later.

The nonwoven fabric of the present embodiment has a basis weight of about 10 g / m ² to 45 g / m ² and preferably has a whiteness of 10 to 35, more preferably 12 to 25 when it does not have a crimping portion. .. Alternatively, the nonwoven fabric of the present embodiment has a whiteness of preferably 0.5 to 1.35, more preferably 0.7 to 1.25, without a crimping portion. Alternatively, the nonwoven fabric of the present embodiment preferably has a brightness of 20 to 55, more preferably 30 to 45 when the basis weight is about 10 g / m ² to 45 g / m ² without a crimping portion. Alternatively, the nonwoven fabric of the present embodiment has a lightness per basis weight of preferably 1 to 2.5, more preferably 1.2 to 2.3, without a crimping portion.

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 it does not have a crimping portion, it preferably has a whiteness of 10 to 27, and more preferably a whiteness of 15 to 24. Alternatively, the nonwoven fabric of the present embodiment has a whiteness of preferably 0.5 to 1.3, more preferably 0.8 to 1.2 per basis weight in a state without a crimping portion. Alternatively, the nonwoven fabric of the present embodiment preferably has a brightness of 20 to 46, more preferably 30 to 44 when the basis weight is about 12 g / m ² to 30 g / m ² without a crimping portion. Alternatively, the nonwoven fabric of the present embodiment has a lightness per basis weight of preferably 1.6 to 2.3, more preferably 1.8 to 2.25 without a crimping portion. The non-woven fabric of the present embodiment covers the surface of the film or paper, for example, for improving the tactile sensation of the film or paper on which a drawing of a character or animal is printed, or for protecting the film or paper. You may use it. In that case, the non-woven fabric of the present embodiment can give a good tactile sensation to the film or the like, or give protection, and can make the drawing well visible.

The flexibility (drapeability) of the nonwoven fabric of the present embodiment can be evaluated, for example, by a value obtained by dividing the total rigidity measured by using a handle ometer by the basis weight, that is, the rigidity per basis weight. .. The method of measuring the rigidity and softness measured by using the handle omimeter is as described later. The total rigidity and softness per basis weight of the nonwoven fabric of the present embodiment is preferably 0.5 to 2.2, more preferably 0.8 to 2.0, and particularly preferably 1. It is 0 to 1.8. Such a non-woven fabric having a rigidity per basis weight is soft and has excellent followability to the bent portion when used against the bent portion.

The nonwoven fabric of the present embodiment can also be obtained as having a large lateral flexibility. Specifically, in the nonwoven fabric of the present embodiment, the total of the rigidity in the vertical direction / the total of the rigidity in the horizontal direction is preferably 2.1 to 3.5, more preferably 2.1 to 3. It is 0.0, particularly preferably 2.2 to 2.8. If the sum of vertical stiffness / sum of lateral stiffness is within this range, it is easier to bend when bending along a direction parallel to the vertical direction, and flexibility in a specific direction is required. Suitable for use in various applications. Here, the rigidity in the vertical direction refers to the ease of bending when the nonwoven fabric is bent in a direction orthogonal to the longitudinal direction, and the rigidity in the horizontal direction refers to the flexibility of the nonwoven fabric orthogonal to the transverse direction thereof. Refers to the ease of bending when bent in the direction.

The non-woven fabric of the present embodiment also allows a liquid (eg, menstrual blood, urine, stool, or cage) to pass through the absorbent body when used in direct or indirect contact with the absorbent body in an absorbent article. It can be absorbed and effectively suppresses the return of the liquid absorbed by the absorber to the non-woven fabric side (wet back). In particular, the non-woven fabric of the present embodiment effectively suppresses the return of the liquid absorbed from the second time onward, especially the second and third times, to the non-woven fabric side when the liquid is absorbed by the absorber in a plurality of times. can. Therefore, when the nonwoven fabric of the present embodiment is used as a surface sheet of an absorbent article or a sheet arranged between the surface sheet and the absorbent body, the surface in contact with the user's skin returns from the absorbent body. It is possible to give the user a comfortable feeling of use by making it difficult to get wet with the coming liquid.

(Manufacturing method of non-woven fabric)
The non-woven fabric of this embodiment is
Producing a fiber web containing 20% by mass or more of split-type composite fibers A hot air processing process is performed on the fiber web by applying hot air at a temperature at which the component having the lowest melting point among the components constituting the split-type composite fiber softens or melts. It is a manufacturing method that includes
The fiber web is not mechanically entangled,
It can be manufactured by a manufacturing method in which the hot air processing is carried out without applying a linear pressure of 10 kg / cm or more to the fiber web.

The fiber web can be made 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 array web, and a wet papermaking web. From the viewpoint of suppressing the division of the split type composite fiber, it is preferable to use a card web in which an external force is not easily applied during manufacturing.

The obtained fiber web is subjected to a hot air processing treatment so that a heat-bonded portion is formed by a component having the lowest melting point (the above-mentioned component A) among the components constituting the split type composite fiber. According to the hot air processing, the external force applied to the fiber web during the heat treatment can be reduced, so that the division of the split type composite fiber does not easily proceed during the heat treatment. 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 type heat treatment machine and a hot air blowing type heat treatment machine. Alternatively, the heat treatment using infrared rays may be performed instead of the hot air processing. Heat treatment with infrared rays is also preferably used because it is difficult for an external force to be applied to the fiber web.

Regardless of which method is used for heat treatment, it is preferable that the heat treatment is 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 division of the split composite fiber is promoted, and the non-woven fabric having the desired flexibility, bulkiness and transparency may not be obtained. For example, in the hot air processing, a mesh or the like may be placed on the fiber web for the purpose of preventing the fiber web from turning over or adjusting the shape of the non-woven fabric after heat treatment, but the weight is 10 kg / cm or more. Select a mesh or the like as appropriate so that the linear pressure of is not applied.

The temperature during the hot air processing is appropriately selected so that the A component of the split type composite fiber is softened or melted, whereby a heat-bonded portion is formed. For example, when the melting point of the component _A is TA ° C., a temperature of ( _TA ) ° C. or higher, which is lower than the melting point of the other constituents of the split type composite fiber, may be selected. Specifically, when the component A is, for example, high-density polyethylene, hot air having a temperature of 130 ° C. to 150 ° C. may be blown.

No mechanical entanglement treatment is performed when manufacturing the non-woven fabric. This is to suppress the progress of division of the split type composite fiber due to the force applied during the mechanical entanglement process. Mechanical entanglement treatments are, for example, needle punching treatments and high pressure fluid flow treatments. Therefore, according to this manufacturing method, a non-woven fabric in which fibers are integrated only by thermal adhesion can be obtained.

The method for producing a nonwoven fabric of the present embodiment may further include partially forming a thermocompression bonding portion. The thermocompression bonding portion can be formed, for example, by thermal roll processing using an embossed roll. For the formation of the thermocompression bonding portion, for example, the temperature of the embossed roll is set to ( _TA -50) ° C. or higher ( _TA +30) ° C. or lower (TA is the melting point of the _A component), and the temperature is 10 kg / cm to 150 kg / cm. It may be carried out by applying linear pressure. The shape of the embossed roll is appropriately selected according to the shape to be formed as the thermocompression bonding portion. As described above, since the pressure is applied in the thermocompression bonding portion, the division of the split type composite fiber progresses, and the degree of division becomes higher than that in the non-thermocompression bonding portion, and therefore the non-thermocompression bonding portion. Less transparent than.

(Use)
The non-woven fabric of the present embodiment can be used for various purposes, and can be used alone or in combination with paper, other non-woven fabrics, films, sheets, etc. (Panty liner), surface materials for various sanitary articles such as incontinence pads, sheets placed between the surface material and absorber, sheets for absorbent articles such as back materials, skin covering sheets (face mask, affixing) It can be used for applications such as agent base cloth), interpersonal wipers (sweat wipe sheets, makeup remover sheets, etc.), and various animal wiper sheets.

When the nonwoven fabric of the present embodiment is used as a surface material of an absorbent article or a sheet arranged between the surface material and the absorber, as described above, the liquid is particularly absorbed when the liquid is absorbed for the second time. It is hard to return and can give a comfortable feeling to the user. Further, the backing material for sanitary articles using the nonwoven fabric of the present embodiment may be in a form in which the nonwoven fabric of the present embodiment is arranged on the surface of a liquid-impermeable sheet. In that case, since the non-woven fabric of the present embodiment has high transparency, when a pattern is printed on a liquid-impermeable sheet, it is made to be clearly visible.

Hereinafter, this embodiment will be described with reference to examples.
The following fibers were prepared as the 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, fiber diameter of 16 μm, and fiber length of 51 mm. Split-type composite fiber (volume ratio 50:50 (polyethylene terephthalate: high-density polyethylene)) (trade name: DFS (SH), manufactured by Daiwa Bow Polytech Co., Ltd.) )

[Core sheath type composite fiber 1]
Core-sheath composite fiber (core: polypropylene, sheath: high-density polyethylene, volume) consisting of a combination of polypropylene (melting point 167 ° C) / high-density polyethylene (melting point 130 ° C) with a fineness of 1.6 dtex, fiber diameter of 16 μm, and fiber length of 51 mm. Ratio 65: 35 (core: sheath)) (Product name NBF (H) manufactured by Daiwa Bow Polytec Co., Ltd.)
[Core sheath type composite fiber 2]
An eccentric core sheath type composite consisting of a combination of polyethylene terephthalate (melting point 255 ° C.) / high-density polyethylene (melting point 130 ° C.) with a fineness of 3.3 dtex, fiber diameter of 21 μm, and fiber length of 51 mm, and 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 Daiwa Bow Polytech Co., Ltd.)
The eccentricity was calculated based on the following equation.

(Example 1)
A parallel web was produced at a web weight of 20 g / m ² using a parallel card machine using only the split type composite fiber 1 to which the primary hydrophilic fiber treatment agent was attached. This fiber web was heat-treated for 15 seconds in a hot air penetrating 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 to obtain a non-woven fabric. The primary hydrophilic fiber treatment agent refers to a treatment agent that imparts the property that the hydrophilicity is significantly reduced after being brought into contact with water once.

(Example 2)
A parallel web was produced at a web weight of 50 g / m ² using a parallel card machine using only the split type composite fiber 1 to which the durable hydrophilic fiber treatment agent was attached. This fiber web is heat-treated for 15 seconds in a hot air penetrating 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, with a grain size of 51.3 g / m ² and a thickness of 2. A non-woven fabric of .74 mm was obtained.

(Example 3)
Using only the split type composite fiber 1 to which the fiber treatment agent having a degree of hydrophilicity smaller than that used in Example 2 is attached, a parallel web is formed at a web weight of 50 g / m ² using a parallel card machine. Made. This fiber web is heat-treated for 15 seconds in a hot air penetrating heat treatment machine set at a temperature of 135 ° C. to form a heat-bonded portion with polyethylene of the split type composite fiber 2, having a grain size of 52.4 g / m ² and a thickness of 2. A non-woven fabric of .86 mm was obtained.

(Example 4-1)
Using 20% by mass of the split type composite fiber 1 and 80% by mass of the core-sheath type composite fiber 2, a parallel web was produced at a web weight of 50 g / m ² using a parallel card machine. In this example, both the split type composite fiber 1 and the core-sheath type composite fiber 2 were used with a durable hydrophilic fiber treatment agent attached. This fiber web is heat-treated for 15 seconds in a hot air penetrating 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 grain size is 48.7 g. A non-woven fabric having a thickness of / m ² and a thickness of 4.23 mm was obtained.

(Example 4-2)
Using 20% by mass of the split type composite fiber 1 and 80% by mass of the core-sheath type composite fiber 2, a parallel web was produced at a web weight of 50 g / m ² using a parallel card machine. In this example, both the split type composite fiber 1 and the core-sheath type composite fiber 2 were used with a durable hydrophilic fiber treatment agent attached. This fiber web is heat-treated for 15 seconds in a hot air penetrating 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 grain size is 49.9 g. A non-woven fabric having a thickness of / m ² and a thickness of 4.43 mm was obtained.

(Comparative Example 1)
Using only the core-sheath type composite fiber 1, a non-woven fabric having a heat-bonded portion formed by the sheath portion was produced by the same procedure as that adopted in Example 1. The core-sheath type composite fiber 1 was used with a primary hydrophilic fiber treatment agent attached. The 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 non-woven fabric having a heat-bonded portion formed by the sheath portion was produced by the same procedure as that adopted in Example 2. The core-sheath type composite fiber 2 was used with a durable hydrophilic fiber treatment agent attached. The 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 non-woven fabric having a heat-bonded portion formed by the sheath portion was produced by the same procedure as that adopted in Example 2. The core-sheath type composite fiber 2 was used with a durable hydrophilic fiber treatment agent attached. The weight of the obtained nonwoven fabric was 48.1 g / m ² , and the thickness was 4.82 mm.

[Metsuke, thickness, specific volume, flexibility]
Table 1 shows the basis weight, thickness (thickness of non-thermocompression bonding portion), and specific volume of Example 1 and Comparative Example 1, and the basis weight and thickness (non-thermocompression bonding portion) of Example 4-1 and Comparative Example 2-1. The thickness of the crimping portion) and the specific volume are shown in Table 2. Further, the results of evaluating the flexibility of Example 1 and Comparative Example 1 are also shown in Table 1, and the results of evaluating the flexibility of Examples 4-1 and Comparative Example 2-1 are also shown in Table 2.
The thickness of the non-woven fabric was measured using a thickness measuring machine (trade name: THICKNESS GAUGE model CR-60A, manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.) with a load of 2.94 cN per 1 cm ² of the sample.

The drape property (rigidity and softness) of the non-woven fabric was measured according to JIS L 1096 6.19.5 E method (handle ometer method). Specifically, it was measured by the following procedure.
Place the test piece with a length of 20 cm and a width of 20 cm on the sample table so that the measurement direction of the test piece is perpendicular to the slot (gap width 10 mm).
Next, when the blade of the penetrator adjusted to be lowered to 8 mm from the surface of the sample table is lowered and the test piece is pushed in, 6.7 cm (1/3 of the width of the test piece) from either side. At the position, the resistance value against pushing is read at the points where the front and back are different in the vertical direction and the horizontal direction. As the resistance value, the maximum value (g) indicated by the microammeter is read.
The measurement is performed in the direction parallel to the MD direction (also called the mechanical direction and the vertical direction) and the CD direction (also called the width direction and the horizontal direction) of the non-woven fabric, and the rigidity and softness are measured at two different points in the direction parallel to the CD direction. And then measure at two different points in the direction parallel to the MD direction.
Measurements are made three times at each measurement point, and the average value is taken as the rigidity of each measurement point (MD-1, MD-2, CD-1, CD-2), and the sum and sum of these are divided by the scale. The value obtained by dividing the sum of the rigidity and the softness in the MD direction by the sum of the stiffness and the softness in the CD direction is evaluated as the drape property. In the table, MD-1 and MD-2 are values measured by placing the sample on the sample table so that the vertical direction of the sample is orthogonal to the length direction of the slot, and CD-1 and CD-2 are the values measured by placing the sample on the sample table. It is a value measured by placing the sample on the sample table so that the lateral direction of is orthogonal to the length direction of the slot.

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

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

Although Example 1 and Comparative Example 1 are composed of fibers having the same fiber diameter, Example 1 has smaller whiteness and lightness than Comparative Example 1 and exhibits high transparency. ..

The nonwoven fabrics obtained in Example 1 and Comparative Example 1 were respectively subjected to thermal roll processing using embossed rolls to form a thermocompression bonding portion. For thermal roll processing, an embossed roll provided with a columnar convex portion having a diameter of 1 mm and a height of 0.5 mm (embossed area of the convex portion: 0.79 mm ² ) is used, the temperature is 100 ° C., and the linear pressure is 20 kg /. It was set to cm. In the non-woven fabric, the thermocompression bonding portion occupied 19.7% of the total area of the non-woven fabric.

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

In both Example 1 and Comparative Example 1, a film was formed of molten polyethylene in the thermocompression bonding portion. In Example 1, it was confirmed that the ultrafine fibers were formed because the division of the split type composite fiber was promoted at the thermocompression bonding portion (FIG. 4). Further, in the non-thermocompression bonding portion of Example 1, although formation of a peeled portion (crack) and ultrafine fibers was observed in some of the fibers due to the division of the split type composite fiber, the ultrafine fibers had a fiber length. It did not exist continuously in excess of 30%, and the division was suppressed as a whole (FIGS. 2 and 3). Further, in Example 1, the contour of the thermocompression bonding portion was clearer than that of Comparative Example 1, and the shape of the thermocompression bonding portion could be visually recognized more clearly.

[Liquid return property]
The liquid returnability of Examples 2, 3, 4-2 and Comparative Example 2-2 was evaluated. The evaluation results are shown in Table 4. The liquid returnability was evaluated by the following method.
(Liquid return property)
(1) The following items were prepared in order to measure the amount of liquid return.
Absorber (commercially available baby diaper disassembled and taken out)
Plate with injection tube (inner diameter 2.5 cm at the bottom of the tube)
0.9% saline (colored with blue dye)
Filter paper (ADVANTEC (registered trademark) No. 2 manufactured by Toyo Filter Paper Co., Ltd.) 10 cm x 10 cm
Weight (5 kg) 10 cm x 10 cm
(2) Method The amount of liquid returned was measured according to the following procedure.
(I) Place a non-woven fabric sample (vertical 42 cm x horizontal 21 cm) on the absorber, and place a plate with an injection tube on it.
(Ii) Inject 50 ml of physiological saline warmed to about 37 ° C. from a cylinder. At this time, the saline solution is left until it cannot be seen from the surface of the non-woven fabric (the saline solution cannot be confirmed as a liquid).
(Iii) Remove the plate with the injection tube and let stand for 10 minutes.
(Iv) After 10 minutes, place filter paper (30 sheets) on the non-woven fabric and place a 5 kg weight for 20 seconds. After that, the mass of the filter paper is measured (the difference in mass between the filter paper before being placed on the non-woven fabric and the filter paper after being placed on the non-woven fabric and the weight is placed corresponds to the amount of reversion).
(Vi) Return to (i) above and perform the second measurement.
For 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 taken as the liquid return amount of the sample.

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

Since the nonwoven fabric of the present embodiment is flexible and does not easily return to liquid, it is suitably used as a constituent member of, for example, an absorbent article.

Claims (10)

It contains 20% by mass or more of split-type composite fibers composed of two components, _A component having a melting point of TA ° C and _B component having a melting point higher than TA ° C by 10 ° C or more, and the fibers are split-type composite fibers. It is a non-woven fabric which is adhered by the A component of the above to form an adhesive portion.
The split type composite fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less.
The split-type composite fiber is non-heat-splitable and does not cause peeling between sections when heated at TA _- 5 ° C for 60 seconds.
The split type composite fiber has a fineness of 0.6 dtex or more and 4.8 dtex or less.
In the split type composite fiber, the volume ratio of the A component and the B component is 4: 6 to 6: 4 (A: B) .
In the split type composite fiber, neither the A component nor the B component is kneaded with the hydrophilic agent.
The specific volume of the non-woven fabric is 10 cm ³ / g or more and 54.6 cm ³ / g or less.
Non-woven fabric. It contains 20% by mass or more of split-type composite fibers composed of two components, _A component having a melting point of TA ° C and _B component having a melting point higher than TA ° C by 10 ° C or more, and the fibers are split-type composite fibers. It is a non-woven fabric that is adhered by the A component of No. 1 to form an adhesive portion and a film-like crimping portion is partially formed.
The split type composite fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less.
The split-type composite fiber is non-heat-splitable and does not cause peeling between sections when heated at TA _- 5 ° C for 60 seconds.
The split type composite fiber has a fineness of 0.6 dtex or more and 4.8 dtex or less.
In the split type composite fiber, the volume ratio of the A component and the B component is 4: 6 to 6: 4 (A: B).
In the split type composite fiber, neither the A component nor the B component is kneaded with the hydrophilic agent.
The degree of division of the split type composite fiber in the crimping portion is larger than the degree of division of the split type composite fiber in the portion other than the crimping portion.
The specific volume of the non-woven fabric is 10 cm ³ / g or more and 54.6 cm ³ / g or less.
Non-woven fabric. It contains 20% by mass or more of split-type composite fibers composed of two components, _A component having a melting point of TA ° C and _B component having a melting point higher than TA ° C by 10 ° C or more, and the fibers are split-type composite fibers. It is a non-woven fabric which is adhered by the A component of the above to form an adhesive portion.
The split type composite fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less.
The split type composite fiber has a fineness of 0.6 dtex or more and 4.8 dtex or less.
In the split type composite fiber, the volume ratio of the A component and the B component is 4: 6 to 6: 4 (A: B).
In the split type composite fiber, neither the A component nor the B component is kneaded with the hydrophilic agent.
The ultrafine fibers formed by dividing or peeling off one of the multiple sections constituting the split-type composite fiber are continuously present at a length exceeding 30% of the fiber length of the split -type composite fiber. Zu ,
The specific volume of the non-woven fabric is 10 cm ³ / g or more and 54.6 cm ³ / g or less.
Non-woven fabric. It contains 20% by mass or more of split-type composite fibers composed of two components, _A component having a melting point of TA ° C and _B component having a melting point higher than TA ° C by 10 ° C or more, and the fibers are split-type composite fibers. It is a non-woven fabric that is adhered by the A component of No. 1 to form an adhesive portion and a film-like crimping portion is partially formed.
The split type composite fiber is a short fiber having a fiber length of 10 mm or more and 100 mm or less.
The split type composite fiber has a fineness of 0.6 dtex or more and 4.8 dtex or less.
In the split type composite fiber, the volume ratio of the A component and the B component is 4: 6 to 6: 4 (A: B).
In the split type composite fiber, neither the A component nor the B component is kneaded with the hydrophilic agent.
The degree of division of the split type composite fiber in the crimping portion is larger than the degree of division of the split type composite fiber in the portion other than the crimping portion.
In the portion other than the crimping portion, the ultrafine fiber formed by dividing or peeling off one of the plurality of sections constituting the split type composite fiber has a length exceeding 30% of the fiber length of the split type composite fiber. Then it doesn't exist continuously,
The specific volume of the non-woven fabric is 10 cm ³ / g or more and 54.6 cm ³ / g or less.
Non-woven fabric. The nonwoven fabric according to any one of claims 1 to 4, wherein the component A is high-density polyethylene. The nonwoven fabric according to any one of claims 1 to 5, which has a basis weight of 10 g / m ² or more and 55 g / m ² or less.
Non-woven fabric. It is a split type composite fiber composed of two components, _A component having a melting point of TA ° C and _B component having a melting point higher than TA ° C by 10 ° C or more, and has a fineness of 0.6 dtex or more and 4.8 dtex or less. The volume ratio of the A component and the B component is 4: 6 to 6: 4 (A: B), and the hydrophilic agent is not kneaded into either the A component or the B component. Producing a fiber web containing 20% by mass or more of fibers The fiber web is subjected to a hot air processing treatment in which hot air at a temperature at which the component A constituting the split type composite fiber is softened or melted is applied.
The fiber web is not mechanically entangled,
Perform hot air processing without applying a linear pressure of 10 kg / cm or more to the fiber web.
A method for producing a non-woven fabric having a specific volume of 10 cm ³ / g or more and 54.6 cm ³ / g or less . The manufacturing method according to claim 7, further comprising partially forming a thermocompression bonding portion. A sheet for an absorbent article containing 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 arranged between the surface material and the absorber.

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