Nonwoven fabric and manufacturing method thereof, sheet impregnated with liquid and wiping sheet

Abstract

To provide a nonwoven fabric and a manufacturing method thereof, a sheet impregnated with liquid, and a wiping sheet.SOLUTION: The nonwoven fabric (10) contains cellulosic fibers (13), adhesive core-sheath type conjugate fibers (11), and non-adhesive core-sheath type conjugate fibers (14). Content percentage of the adhesive core-sheath type conjugate fibers is 5 mass% or more and 20 mass% or less, and content percentage of the cellulosic fibers is 45 mass% or more and less than 90 mass%, with respect to total mass of the nonwoven fabric. The adhesive core-sheath type conjugate fibers have bonded parts where the fibers are bonded at intersections with each other. A sheath part of the non-adhesive core-sheath type conjugate fiber contains ethylene-vinyl alcohol copolymer.SELECTED DRAWING: Figure 1

Description

Related Application

[0001] This application claims the priority of Japanese Patent Application No. 2020-53332 filed on March 24, 2020, and the entire disclosure of which is incorporated herein by reference and made a part of this application.

Technical Field

[0002] This invention relates to a nonwoven fabric, a liquid-impregnated sheet, and a wiping sheet.

Background Art

[0003] In recent years, due to the ease of use, liquid-containing sheets obtained by impregnating nonwoven fabrics with a liquid (liquid-containing sheet) have been used, and these are used as face masks, coating sheets, wiping sheets, etc. as liquid-containing sheets.

[0004] Patent Document 1 (Japanese Patent Laid-Open No. 2008-261067) discloses a nonwoven fabric sheet in which solvent-spun cellulose fibers having a fiber length of 30 to 60 mm and core-sheath composite fibers are intertwined with each other. The core-sheath composite fiber consists of a sheath portion and a core portion, the sheath portion is an ethylene-vinyl alcohol copolymer, and the core portion is made of a hydrophobic resin and has a diameter of 5 μm to 15 μm. In this document, it is possible to provide a soft and bulky fiber intertwined body by forming a nonwoven fabric from the solvent-spun cellulose fibers and the core-sheath composite fibers in a uniformly mixed state by a water entanglement method.

[0005] Patent Document 2 (International Publication No. 2015 / 046301) discloses a liquid-retaining sheet formed of a nonwoven fabric containing 50% by mass or more of high-elastic fibers having a Young's modulus of 30 cN / T or more. In this document, it is possible to provide a liquid-retaining sheet and a face mask in which, when impregnated with a liquid component such as a beauty liquid (cosmetic), the liquid component quickly returns to the sheet even when pressed with a finger.

Prior Art Documents

Patent Documents

[0006] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2008-261067 Patent Document 2 International Publication No. 2015 / 046301 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, in Patent Document 1 and Patent Document 2, since the form stability when using the nonwoven fabric is inferior, there is room for improvement.

[0008] Therefore, an object of the present invention is to provide a nonwoven fabric having excellent form stability, as well as a liquid-impregnated sheet and a wiping sheet using the same.

[0009] Another object of the present invention is to provide a nonwoven fabric having excellent form stability and good water retention rate and liquid release rate, as well as a liquid-impregnated sheet and a wiping sheet using the same.

[0010] Still another object of the present invention is to provide a nonwoven fabric that is difficult to slip between nonwoven fabrics when used in a folded state and has excellent handleability, and has a small friction between the nonwoven fabric and the skin and can reduce the skin burden, as well as a liquid-impregnated sheet and a wiping sheet using the same. MEANS FOR SOLVING THE PROBLEMS

[0011] As a result of intensive studies to achieve the above object, the inventors of the present invention found that from the viewpoint of improving form stability, when using adhesive core-sheath composite fibers at a predetermined ratio and forming an adhesive portion at the intersection portion where the adhesive core-sheath composite fibers are in contact, a pseudo-net state can be formed, and the form stability of the entire nonwoven fabric can be improved.

[0012] On the other hand, the improvement in morphological stability by the adhesive core-sheath composite fiber may not provide sufficient liquid drainage when the non-woven fabric is applied to the skin under a certain degree of compression, and further, since the space for the non-woven fabric to hold the liquid decreases, it may cause a decrease in the water retention rate. Therefore, we have identified a new problem that improvement of other fibers is required. As a result of intensive studies on this new problem, when a pseudo-net state is formed, the liquid drainage rate and the water retention rate can be controlled by including a cellulose-based fiber in the non-woven fabric and a non-adhesive core-sheath composite fiber having an ethylene-vinyl alcohol copolymer (abbreviation: EVOH) in the sheath portion as a third component, and setting the ratio of the cellulose-based fiber within a specific range, and thus the present invention has been completed.

[0013] That is, the present invention can be configured in the following aspects. 〔Aspect 1〕 A non-woven fabric containing a cellulose-based fiber, an adhesive core-sheath composite fiber, and a non-adhesive core-sheath composite fiber, with respect to the total mass of the non-woven fabric, the content of the adhesive core-sheath composite fiber is 5% by mass or more and 20% by mass or less (preferably 7% by mass or more and 17% by mass or less, more preferably 8% by mass or more and 15% by mass or less), the content of the cellulose-based fiber is 45% by mass or more and less than 90% by mass (preferably 50% by mass or more and less than 90% by mass, more preferably 55% by mass or more and 88% by mass or less, particularly 65% by mass or more and 85% by mass or less), and the adhesive core-sheath composite fiber has an adhesive portion that binds at the intersection where they cross each other, the non-adhesive core-sheath composite fiber has a sheath portion containing an ethylene-vinyl alcohol copolymer, non-woven fabric. 〔Aspect 2〕 The non-woven fabric according to Aspect 1, wherein the mass ratio of the content (T) of the cellulose-based fiber to the content (N) of the non-adhesive core-sheath composite fiber is T / N = 99 / 1 to 51 / 49 (preferably 95 / 5 to 55 / 45, more preferably 95 / 5 to 65 / 35, still more preferably 95 / 5 to 75 / 25). 〔Aspect 3〕 The non-woven fabric according to Aspect 1 or 2, wherein the elongation rate when absorbing the saturated moisture content is 40% or less (preferably 35% or less, more preferably 31% or less). 〔Aspect 4〕 The non-woven fabric according to any one of Aspects 1 to 3, wherein the compression hardness at 30% compression deformation is 0.750 to 1.500 N / mm (preferably 0.800 to 1.400 N / mm, more preferably 0.850 to 1.300 N / mm) when the non-woven fabric is impregnated with a mixed solution of distilled water and glycerin (mass ratio of distilled water / glycerin = 5 / 4) at 500% by mass based on the mass of the non-woven fabric and left for 24 hours. 〔Aspect 5〕 The non-woven fabric according to any one of Aspects 1 to 4, wherein the liquid discharge rate for 10 seconds released at 30% compression deformation is 7 to 14% (preferably 8 to 12%) when the non-woven fabric is impregnated with a mixed solution of distilled water and glycerin (mass ratio of distilled water / glycerin = 5 / 4) at 500% by mass based on the mass of the non-woven fabric and left for 24 hours. 〔Aspect 6〕 The non-woven fabric according to any one of Aspects 1 to 5, wherein the water retention rate is 1145% or more (preferably 1180% or more, more preferably 1200% or more). 〔Aspect 7〕 The non-woven fabric according to any one of Aspects 1 to 6, wherein the difference (A - C) between the static friction coefficient (A) between non-woven fabrics containing 400% by mass of distilled water and the static friction coefficient (C) between a non-woven fabric containing 400% by mass of distilled water and bioskin (artificial skin) is 0.0170 to 0.1000 (preferably 0.0200 to 0.0900, more preferably 0.0300 to 0.0800). 〔Aspect 8〕 The non-woven fabric according to any one of Aspects 1 to 7, wherein the static friction coefficient (A) between non-woven fabrics containing 400% by mass of distilled water is 0.0550 to 0.0900 (preferably 0.0600 to 0.0900, more preferably 0.0650 to 0.0880). 〔Aspect 9〕 The nonwoven fabric according to any one of Aspects 1 to 8, wherein the static friction coefficient (C) between the nonwoven fabric containing 400% by mass of distilled water and the bioskin (artificial skin) is 0.0450 or less (preferably 0.0430 or less). 〔Aspect 10〕 The nonwoven fabric according to any one of Aspects 1 to 9, wherein the hairiness length per thickness (1-fold) of the nonwoven fabric is 10-fold or less (preferably 8-fold or less, more preferably 5-fold or less). 〔Aspect 11〕 A liquid-impregnated sheet comprising the nonwoven fabric according to any one of Aspects 1 to 10. 〔Aspect 12〕 A wiping sheet comprising the nonwoven fabric according to any one of Aspects 1 to 10. 〔Aspect 13〕 A method for manufacturing the nonwoven fabric according to any one of Aspects 1 to 10, which comprises a step of performing entanglement treatment on a web containing cellulose fibers, adhesive core-sheath composite fibers, and non-adhesive core-sheath composite fibers, wherein the content of the adhesive core-sheath composite fibers is 5% by mass or more and 20% by mass or less, and the content of the cellulose fibers is 45% by mass or more and less than 90% by mass with respect to the total mass of the web, to form a web having an entangled structure; and a step of forming an adhesive portion between the adhesive core-sheath composite fibers without forming an adhesive portion between the non-adhesive core-sheath composite fibers in the web having the entangled structure. The method for manufacturing a nonwoven fabric comprises at least these steps. 〔Aspect 14〕 The method for manufacturing a nonwoven fabric according to Aspect 13, wherein the entanglement treatment is water jet entanglement. 〔Aspect 15〕 The method for manufacturing a nonwoven fabric according to Aspect 13 or 14, wherein in the step of forming the adhesive portion, heat treatment is performed at a temperature lower than the melting point of the sheath portion of the non-adhesive core-sheath composite fiber and higher than the melting point of the sheath portion of the adhesive core-sheath composite fiber.

[0014] In addition, any combination of at least two components disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of the claims recited in the claims is included in the present invention.

Advantages of the Invention

[0015] In the present invention, it is possible to provide a nonwoven fabric excellent in form stability, water retention, liquid discharge property, etc. Particularly preferably, when folded and used, the nonwoven fabrics are difficult to slip and have excellent handleability, and the friction between the nonwoven fabric and the skin is small, so that a nonwoven fabric capable of reducing the skin burden can be provided.

Brief Description of the Drawings

[0016] This invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and the drawings are for illustrative and explanatory purposes only and should not be used to define the scope of this invention. The scope of this invention is determined by the appended claims.

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0017] The nonwoven fabric of the present invention includes a cellulose-based fiber, an adhesive core-sheath type composite fiber having an adhesive part, and a non-adhesive core-sheath type composite fiber in which the sheath part contains an ethylene-vinyl alcohol copolymer.

[0018] (Cellulose-based fiber) Examples of the cellulose-based fiber include vegetable fibers such as cotton, hemp, and pulp, regenerated fibers such as rayon and cupra, and purified cellulose fibers such as lyocell (tencel). These cellulose-based fibers may be used alone or in combination of two or more. Among these, rayon is preferable in terms of easy availability and easy handling. Further, the cellulose-based fiber may be partially fibrillated, but it is preferably not substantially fibrillated from the viewpoint of preventing fine fibers from adhering to the face.

[0019] With respect to the total mass of the nonwoven fabric of the present invention, the content of the cellulose-based fiber is 45% by mass or more and less than 90% by mass. If the content of the cellulose-based fiber is less than 45% by mass, the water retention property will be low. On the other hand, if the content of the cellulose-based fiber is 90% by mass or more with respect to the total mass of the nonwoven fabric of the present invention, the sheet will become high density and the liquid drainage property will decrease. Preferably, with respect to the total mass of the nonwoven fabric, the content of the cellulose-based fiber may be 50% by mass or more and less than 90% by mass, more preferably 55% by mass or more and 88% by mass or less, and particularly 65% by mass or more and 85% by mass or less.

[0020] The fineness of the cellulose-based fiber is not particularly limited, but for example, it may be 1.2 to 2.2 dtex, and more preferably 1.5 to 1.9 dtex. The average fiber length of the cellulose-based fiber is not particularly limited, but from the viewpoints of manufacturing workability, mechanical properties of the nonwoven fabric, etc., for example, it may be 10 to 100 mm, preferably 20 to 80 mm, and more preferably 30 to 60 mm.

[0021] (Adhesive core-sheath composite fiber) The nonwoven fabric of the present invention contains 5% by mass or more and 20% by mass or less of the adhesive core-sheath composite fiber with respect to the total mass of the nonwoven fabric, and the adhesive core-sheath composite fiber has an adhesive part that is joined at the intersection where they cross each other. In the adhesive part, since the sheath parts of the fibers can be mutually dissolved and integrated, good form stability can be imparted.

[0022] By containing the adhesive core-sheath composite fiber at a predetermined ratio, the adhesive part can be formed within a suitable range, and the form stability of the nonwoven fabric can be improved. Further, since the sheath parts of the adhesive core-sheath composite fiber are mutually dissolved in the adhesive part, a pseudo-net state in which the adhesive core-sheath fibers are integrated can be formed, so that the generation of fluff can be suppressed when the nonwoven fabric is rubbed. The content of the adhesive core-sheath composite fiber is preferably 7% by mass or more and 17% by mass or less, and more preferably 8% by mass or more and 15% by mass or less.

[0023] Next, the core-sheath type composite fiber is composed of a resin component forming the core part and a resin component forming the sheath part, and the sheath part has adhesiveness. As long as the sheath part can form an adhesive part, various resin components can be used, but from the viewpoint of workability, it is preferable that the sheath part has heat fusibility. Preferred sheath parts include polyolefin resins such as polyethylene, polypropylene, modified polymers thereof, blends, and copolymers having heat fusibility, modified polyesters (for example, modified polyethylene terephthalate modified with isophthalic acid), etc. Preferably, they are polyethylene and modified polymers of polyethylene, blends, copolymers, modified polyethylene terephthalate, etc. For example, when a heat-fusible resin is used as the sheath part, the melting point of the heat-fusible resin may be, for example, 80 to 150 °C, and preferably 100 to 140 °C.

[0024] On the other hand, the core part is not particularly limited as long as it can be fibrillated with the sheath part forming the adhesive part and can maintain its use as a fiber even when the sheath part forms an adhesive part, and a resin component suitable for the sheath part is selected. Preferred core parts include, for example, polyolefin resins such as polypropylene, and polyester resins such as polyethylene terephthalate. When a heat-fusible resin is used as the sheath part, the melting point of the resin component of the core part may be, for example, 10 °C or more higher than the melting point of the resin component of the sheath part, preferably 20 °C or more higher, and more preferably 30 °C or more higher.

[0025] For example, as the combination of the core part / sheath part, combinations such as polyethylene terephthalate / polyethylene, polyethylene terephthalate / modified polyethylene terephthalate, polypropylene / polyethylene, and polypropylene / modified polypropylene are suitable. Among them, the combination of polypropylene / polyethylene, which is inexpensive and commonly used in non-woven fabrics, is preferable.

[0026] From the viewpoint of forming a strong bonding part, in the case of the adhesive core-sheath composite fiber, it is preferable that the low melting point component serving as the sheath part covers at least 40% or more, particularly 60% or more, around the core part. Further, the composition ratio of the core part and the sheath part may be, for example, 90 / 10 to 10 / 90 in terms of mass ratio, preferably 80 / 20 to 20 / 80, and more preferably 70 / 30 to 30 / 70.

[0027] The cross-sectional shape of the adhesive core-sheath composite fiber is not particularly limited, and any form such as a round core-sheath, an eccentric core-sheath, or a core-sheath with a non-circular cross-section may be used. From the viewpoint of improving the form stability, the fineness of the adhesive core-sheath composite fiber may be, for example, 0.5 to 10.0 dtex, preferably 1.0 to 5.0 dtex, and more preferably 1.4 to 2.2 dtex. The average fiber length of the adhesive core-sheath composite fiber is preferably in the range of, for example, 10 mm to 80 mm from the viewpoints of manufacturing workability and mechanical properties of the nonwoven fabric. More preferably, it is 30 mm to 70 mm, and still more preferably, it is 35 mm to 60 mm. By using such short fibers in the adhesive core-sheath composite fiber, it is possible to improve the mechanical properties such as the strength and elongation of the nonwoven fabric while enhancing the mobility and entanglement degree of the fibers by the entanglement treatment.

[0028] (Non-adhesive core-sheath composite fiber) In addition to the cellulose-based fibers, the nonwoven fabric of the present invention contains non-adhesive core-sheath composite fibers having a resin with both hydrophilic and lipophilic properties as the sheath part. That is, as the resin having both hydrophilic and lipophilic properties, the sheath part contains an ethylene-vinyl alcohol copolymer (abbreviation: EVOH). Different from the adhesive core-sheath composite fiber, in the non-adhesive core-sheath composite fiber, the ethylene-vinyl alcohol copolymers that are the sheath part do not dissolve in each other and are present in the nonwoven fabric. Due to the presence of such non-adhesive core-sheath composite fibers, the nonwoven fabric can improve its elasticity.

[0029] The EVOH used for the sheath part of the non-adhesive core-sheath composite fiber of the present invention is preferably obtained by saponifying an ethylene-vinyl ester copolymer. As the EVOH component, those having an ethylene content of 25 to 70 mol% are preferably used. From the viewpoint of achieving both hydrophilicity and lipophilicity, those having an ethylene content of 30 to 65 mol% are particularly preferred.

[0030] By using a non-adhesive core-sheath composite fiber using EVOH as the sheath part, the liquid retention (water retention) property of the non-woven fabric when it contains a liquid component can be improved, and the liquid drainage property when the non-woven fabric is compressed to about 30% can be improved.

[0031] In the non-adhesive core-sheath composite fiber, the core part is not particularly limited as long as it is a resin component that can be fibrillated with EVOH. Preferably, from the viewpoint of imparting rigidity to hydrophilic EVOH, it may be a hydrophobic resin component.

[0032] Examples of the hydrophobic resin component include polyester resins such as polyethylene terephthalate, polyolefin resins such as polypropylene, and polyamide resins. From the viewpoint of having higher rigidity than EVOH, polypropylene and polyester resins are preferred, and polyester resins are preferred from the viewpoint of having a higher elastic modulus and being able to improve the morphological stability of the non-woven fabric.

[0033] By using the non-adhesive core-sheath composite fiber, a space for retaining liquid in the non-woven fabric can be formed, not only can the liquid drainage property be controlled, but also due to the non-adhesive property, the friction between the non-woven fabric and the skin is small and the skin burden can be reduced. Furthermore, even when compressed to about 30%, it is possible to impart a suitable compression hardness to the non-woven fabric that is not too hard and not too soft.

[0034] From the perspective of imparting both hydrophilicity and lipophilicity to the fiber surface and controlling the liquid drainage property, in the non-adhesive core-sheath composite fiber, it is preferable that the EVOH serving as the sheath portion covers at least 50% or more, particularly 70% or more, of the periphery of the core portion. Further, the composition ratio of the core portion and the sheath portion may be, for example, 90 / 10 to 10 / 90 by mass ratio, preferably 80 / 20 to 20 / 80, and more preferably 70 / 30 to 30 / 70.

[0035] The cross-sectional shape of the non-adhesive core-sheath composite fiber is not particularly limited, and it may be in any form such as a round core-sheath, an eccentric core-sheath, or a core-sheath with an irregular cross-section. From the perspectives of processability and touch feeling, the fineness of the non-adhesive core-sheath composite fiber may be, for example, 0.5 to 10.0 dtex, preferably 1.0 to 5.0 dtex, and more preferably 1.4 to 2.2 dtex. The average fiber length of the non-adhesive core-sheath composite fiber is preferably in the range of, for example, 10 mm to 80 mm from the viewpoints of manufacturing workability and mechanical properties of the non-woven fabric. More preferably, it is 30 mm to 70 mm, and even more preferably 35 mm to 60 mm. By using such short fibers in the adhesive core-sheath composite fiber, it is possible to improve the mechanical properties such as the strength and elongation of the non-woven fabric while enhancing the mobility and entanglement degree of the fibers by the entanglement treatment.

[0036] The content ratio of the non-adhesive core-sheath composite fiber may be, for example, T / N = 99 / 1 to 51 / 49 as the mass ratio of the content (T) of the cellulose-based fiber and the content (N) of the non-adhesive core-sheath composite fiber, preferably 95 / 5 to 55 / 45, more preferably 95 / 5 to 65 / 35, and even more preferably 95 / 5 to 75 / 25.

[0037] FIG. 1 is a perspective conceptual diagram for explaining a non-woven fabric according to an embodiment of the present invention, and FIG. 2 is an enlarged planar conceptual diagram conceptually showing a part of this non-woven fabric. FIG. 3A is a partial schematic enlarged view showing an enlarged view of part III in FIG. 2, and FIG. 3B is a partial schematic enlarged view for explaining the adhesive portion in FIG. 3A in an enlarged manner.

[0038] As shown in Fig. 1, the nonwoven fabric 10 of the present invention contains cellulose-based fibers 13, adhesive core-sheath composite fibers 11, and non-adhesive core-sheath composite fibers 14. These fibers 11, 13, 14 may be randomly arranged in the nonwoven fabric, or may be arranged mainly in any one direction (for example, the MD direction). In the nonwoven fabric 10, the adhesive core-sheath composite fibers 11 adhere to each other at the intersections where they cross each other, maintaining the shape of the nonwoven fabric.

[0039] Fig. 2 is an enlarged plan view conceptually enlarging a part of Fig. 1, explaining the existence state of the adhesive core-sheath composite fibers 11 and the non-adhesive core-sheath composite fibers 14 in the nonwoven fabric. In Fig. 2, the adhesive core-sheath composite fibers 11 and the non-adhesive core-sheath composite fibers 14 are conceptually illustrated as linear objects. Although the cellulose-based fibers 13 are also distributed as linear objects in the nonwoven fabric, the illustration as linear objects is omitted in the figure. Note that, for simplicity, the figure shows straight linear objects, but any of the fibers may be curved.

[0040] As shown in Fig. 2, the adhesive core-sheath composite fiber 11 has an adhesive portion 12 that adheres to each other at the intersection with other adhesive core-sheath composite fibers 11. On the other hand, the non-adhesive core-sheath composite fibers 14 do not adhere to each other at the intersection with other non-adhesive core-sheath composite fibers 14.

[0041] Note that at the intersection of the adhesive core-sheath composite fiber 11 and the non-adhesive core-sheath composite fiber 14, in some cases, they may appear to adhere to each other due to the appearance of the adhesive core-sheath composite fiber, but usually, no mutually compatible adhesive portion is formed at the intersection. Also, at the intersection of the adhesive core-sheath composite fiber 11 and the cellulose-based fiber 13, usually, no mutually compatible adhesive portion is formed at the intersection.

[0042] As shown in FIG. 2, the bonding portions 12 are formed by the bonding between the sheath-core composite fibers 11, 11 at the intersections where they cross each other, and a plurality of them exist evenly throughout the web. In other words, the plurality of bonding portions 12 are distributed almost uniformly throughout the web. In each bonding portion 12, a part of the sheath portions 11a of the sheath-core composite fibers 11 that cross each other (the portions of the intersections that come into contact with each other) are fused or welded to form a fiber-to-fiber bond.

[0043] Therefore, in the bonding portion 12, unlike mere physical entanglement, it is possible to form fixed points that are fixed in the nonwoven fabric. Therefore, for example, even when the nonwoven fabric is stretched, by using the bonding portion 12 as a gripping portion, it is possible to improve the morphological stability of the nonwoven fabric. Also, since a pseudo-net state can be formed by the bonding portions 12 that are close to each other, it is possible to suppress excessive stretching during use.

[0044] Specifically, as shown in FIGS. 3A and 3B, the sheath-core composite fiber 11 is a composite fiber including a sheath portion 11a and a core portion 11b covered by this sheath portion 11a, and the bonding portion 12 is formed at the intersection portion between the sheath portion 11a of one sheath-core composite fiber 11 and the sheath portion 11a of another sheath-core composite fiber 11. The sheath portion is not particularly limited as long as it has adhesiveness. For example, in the case of a heat-fusible sheath-core composite fiber, in the sheath-core composite fiber 11, a low-melting-point component is applied as the sheath portion 11a, and a high-melting-point component is applied as the core portion 11b.

[0045] The cross-sectional shape of the sheath-core composite fiber 11, when cut in a plane perpendicular to the longitudinal direction, is in the form of a round core-sheath where the outer peripheral surface of the round core portion 11b is covered with a cylindrical sheath portion 11a having a substantially uniform circumferential thickness. However, as described above, the cross-sectional shape of the sheath-core composite fiber is not limited to the form of a round core-sheath, and it may be in any form such as an eccentric core-sheath or a profiled cross-section core-sheath.

[0046] The nonwoven fabric of the present invention may contain fibers other than the above-described cellulose-based fibers, adhesive core-sheath composite fibers, and non-adhesive core-sheath composite fibers as long as the effects of the present invention are not inhibited. Examples of such fibers include polyester-based fibers, polyolefin-based fibers, polyamide-based fibers, acrylic-based fibers, polyvinyl alcohol-based fibers, and the like.

[0047] [Method for manufacturing nonwoven fabric] From the viewpoint of ensuring a space for mixing fibers and impregnating a liquid, the nonwoven fabric can be obtained by forming a web by a dry method using the above-described various fibers, then entangling the fibers in the web by an entangling treatment, and further forming an adhesive portion on the adhesive core-sheath composite fiber by an adhesion treatment.

[0048] Specifically, the cellulose-based fiber, the adhesive core-sheath composite fiber, and the non-adhesive core-sheath composite fiber are mixed and carded by a carding machine to produce a web. Such a web may be a parallel web in which fibers are arranged in the running direction of the carding machine, a cross web in which the parallel web is cross-laid, a random web in which the fibers are randomly arranged, or a semi-random web in which the fibers are arranged to a medium extent between the two. However, considering the high conformability in all directions when using the sheet, a random web is preferable, and considering the high productivity, a semi-random web is preferable.

[0049] The entangling treatment is not particularly limited as long as the fibers can be entangled with each other. However, from the viewpoint of enabling a dense entanglement between the fibers, it is preferable to perform water jet entanglement on the obtained web. The water jet entanglement treatment is, for example, to cause a water stream jetted in a columnar shape at high pressure to collide with the web placed on a porous support member described later, and to densely three-dimensionally entangle and integrate the constituent fibers of the web.

[0050] When applying a three-dimensional entanglement to the web, a method of placing the web on a moving porous support member and treating it one or more times with a water flow at a water pressure of 0.5 to 15 MPa is preferably mentioned. The injection holes are preferably arranged in a row on the nozzle plate in a direction orthogonal to the traveling direction of the web so that the water flow impinges uniformly on the web. In order to enhance the uniformity of the web thickness, the water pressure is particularly preferably in the range of 1.5 to 12 MPa, and it is preferable that the water flow entanglement treatment is performed on both sides of the web at least two or more times each and a total of five or more times. From the viewpoint of making the entanglement of the web uniform, the distance between the injection holes and the web is preferably 1 to 10 cm. Further, the water flow may be ejected, for example, from a nozzle plate in which one or two rows of injection holes having a pore diameter of 0.05 to 0.10 mm and an interval of 0.30 to 1.50 mm are arranged.

[0051] As the porous support member on which the web is placed, for example, a mesh screen or a perforated plate made of metal or resin is used. From the viewpoint of enhancing the flatness of the nonwoven fabric surface, it is preferable that the water flow is entangled on a woven structure of fine fibers (for example, a plain weave structure) in at least the last treatment of the water flow entanglement treatment.

[0052] Furthermore, in order to enhance the surface flatness of the web, among the nozzle plates used in the water flow entanglement treatment on the porous support member, the nozzle plate used in the final stage is preferably one in which one or two rows of injection holes having a pore diameter of 0.05 to 0.10 mm and an interval of 0.30 to 1.00 mm are arranged. <Adhesion step> In the adhesion step, while maintaining the entangled structure in the web, an adhesive portion is formed between the adhesive core-sheath composite fibers. The adhesion step can be appropriately selected according to the resin component used in the adhesive portion between the adhesive core-sheath composite fibers. For example, an adhesive portion may be formed under a solvent in which only the sheath portion of the adhesive core-sheath composite fiber softens, or a heat-fusible core-sheath composite fiber may be used to melt the sheath portion by heat treatment to form an adhesive portion. From the viewpoint of simplicity, the adhesion step by heat treatment is preferable.

[0053] When performing heat treatment, as long as the temperature and the like can be controlled so that an adhesive portion is formed in the adhesive core-sheath composite fiber while no adhesive portion is formed in the non-adhesive core-sheath composite fiber, there is no particular limitation, and various dryers such as a hot air dryer and a cylinder dryer can be used. In the heat treatment step, the amount of heat may be adjusted so that the temperature of the web becomes higher than the melting point of the sheath portion of the adhesive core-sheath composite fiber contained in the web. The web having the adhesive portion formed thereon can be used as the nonwoven fabric of the present invention.

[0054] In the case of the heat-fusible core-sheath composite fiber, a cooling step may be further performed to fix the adhesive portion. In the cooling step, cooling may be performed by appropriately adjusting the time from after the heat treatment step to winding up to release heat from the web, or cooling may be performed using a cooling means. In order to fix the adhesive portion and improve the form stability and fluff prevention of the web, it is preferable to wind up the web after the temperature of the web becomes equal to or lower than the melting point temperature of the sheath portion of the heat-fusible core-sheath composite fiber.

[0055] [Nonwoven fabric] The nonwoven fabric of the present invention is a nonwoven fabric containing a cellulosic fiber, an adhesive core-sheath composite fiber, and a non-adhesive core-sheath composite fiber, wherein the adhesive core-sheath composite fiber has an adhesive portion joined at an intersection intersecting with each other, and the content of the adhesive core-sheath composite fiber is 5% by mass or more and 20% by mass or less with respect to the total mass of the nonwoven fabric, the content of the cellulosic fiber is 45% by mass or more and less than 90% by mass, and the non-adhesive core-sheath composite fiber is a nonwoven fabric in which the sheath portion contains an ethylene-vinyl alcohol copolymer.

[0056] From the viewpoint of the liquid retention property of the nonwoven fabric, etc., the apparent density of the nonwoven fabric may be, for example, in the range of 0.04 to 0.20 g / cm 3 and preferably in the range of 0.06 to 0.15 g / cm 3It may also be within the range. Here, the apparent density is the value obtained by dividing the basis weight of the nonwoven fabric by the thickness. When the apparent density of the nonwoven fabric is too low, the form stability tends to decrease. When the apparent density of the nonwoven fabric is too high, the liquid retention amount tends to decrease. The apparent density of the nonwoven fabric constituting the sheet of the present invention can be obtained by calculation from the basis weight (g / m 2 ) and the thickness (mm) (the apparent density (g / cm 3 ) of the nonwoven fabric = basis weight (g / m 2 ) / thickness (mm) / 1000). The thickness of the nonwoven fabric is measured in accordance with 6.2 of JIS L 1913 "General Test Methods for Nonwoven Fabrics".

[0057] The basis weight of the nonwoven fabric may be, for example, within the range of 10 to 100 g / m 2 , preferably within the range of 20 to 100 g / m 2 , more preferably within the range of 25 to 50 g / m 2 . When the basis weight of the nonwoven fabric is too low, the form stability decreases, and rounding and the like tend to occur when used as a liquid-impregnated sheet. When the basis weight of the nonwoven fabric is too large, the amount of fibers used per sheet and the amount of the impregnating liquid increase, which tends to be disadvantageous in terms of cost.

[0058] The thickness of the nonwoven fabric is not particularly limited either. For example, it may be within the range of 0.05 to 10 mm, preferably within the range of 0.10 to 8 mm, more preferably within the range of 0.20 to 5 mm. When the thickness is too thin, it tends to be difficult to maintain the form of the nonwoven fabric. When the thickness is too thick, the fibrous aggregate in sheet form becomes too thick, and the entanglement between fibers tends to be insufficient.

[0059] The nonwoven fabric of one aspect contains core-sheath type composite fibers with an adhesive at a content within a predetermined range, and has an adhesive part where the core-sheath type composite fibers are joined at the intersections where they cross each other, so it has excellent morphological stability. For example, the nonwoven fabric of the present invention may have an elongation rate of, for example, 40% or less, preferably 35% or less, more preferably 31% or less. The elongation rate may be 0%, but in applications where stretchability is required for the nonwoven fabric, the elongation rate may be 5% or more, more preferably 10% or more. The elongation rate is a value measured by the method described in the examples below.

[0060] The nonwoven fabric of one aspect contains a cellulose-based fiber and a non-adhesive core-sheath type composite fiber having EVOH in the sheath part at a content within a predetermined range, so it is possible to control the liquid drainage property when compressed to 30% of the thickness. After impregnating a mixed solution of distilled water and glycerin (mass ratio of distilled water / glycerin = 5 / 4) at 500% by mass based on the mass of the nonwoven fabric and leaving it for 24 hours, the liquid drainage rate for 10 seconds released during 30% compressive deformation may be, for example, 7 - 14%, preferably 8 - 12%. If the liquid drainage rate is too low, the liquid release property is poor, and if the liquid drainage rate is too high, there is a possibility of liquid dripping due to liquid release. The liquid drainage rate is a value measured by the method described in the examples below.

[0061] The nonwoven fabric of one aspect contains a cellulose-based fiber at a content within a predetermined range and does not have an adhesive part where the non-adhesive core-sheath type composite fibers substantially adhere to each other, so it is possible to sufficiently secure a space for retaining moisture in the nonwoven fabric. Therefore, the water retention rate of the nonwoven fabric may be, for example, 1145% or more, preferably 1180% or more, more preferably 1200% or more. The upper limit of the water retention rate is not particularly limited, but may be, for example, about 1500%. The water retention rate is a value measured by the method described in the examples below.

[0062] The non-woven fabric of one aspect contains cellulose fibers and non-adhesive core-sheath composite fibers having EVOH in the sheath portion at a content rate within a predetermined range. Therefore, for example, the compression hardness may be 0.750 to 1.500 N / mm, preferably 0.800 to 1.400 N / mm, and more preferably 0.850 to 1.300 N / mm. The compression hardness is a value measured by the method described in the examples below. If the compression hardness is too small, excessive liquid discharge may occur during use. For example, when taking out the sheet from the package or folding it, the liquid may be discharged before use. On the other hand, if the compression hardness is too large, the liquid discharge rate tends to decrease.

[0063] The non-woven fabric of one aspect can form a pseudo-net state to suppress the generation of lint. The length of the lint generated on the non-woven fabric may be, for example, 7.0 mm or less, preferably 6.5 mm or less, and more preferably 3.0 mm or less. The length of the lint is a value measured by the method described in the examples below. Also, even when the thickness of the non-woven fabric is thin, it is possible to suppress the length of the lint generated. The length of the lint generated on the non-woven fabric may be, for example, 10 times or less, preferably 8 times or less, and more preferably 5 times or less with respect to the thickness of one sheet of the non-woven fabric.

[0064] When the non-woven fabric of one aspect is used after being folded, it is preferable that no slippage occurs between the non-woven fabrics. Therefore, the static friction coefficient (A) between the non-woven fabrics may be, for example, 0.0550 to 0.0900, preferably 0.0600 to 0.0900, and more preferably 0.0650 to 0.0880. The static friction coefficient (A) between the non-woven fabrics is a value measured by the method described in the examples below, and the non-woven fabric is used in a state containing 400% by mass of distilled water.

[0065] In one aspect, the nonwoven fabric preferably has smoothness when applied to the skin. Therefore, the static friction coefficient (C) between the nonwoven fabric and the bioskin (artificial skin) may be, for example, 0.0450 or less, preferably 0.0430 or less. The static friction coefficient (C) between the nonwoven fabric and the bioskin (artificial skin) is a value measured by the method described in the examples below, and the nonwoven fabric is used in a state containing 400% by mass of distilled water during measurement.

[0066] In one aspect, when the nonwoven fabric is folded and applied to the skin, it is preferable that the nonwoven fabrics do not slip against each other, while having smoothness against the skin. Therefore, the difference (A - C) between the static friction coefficient (A) between the nonwoven fabrics and the static friction coefficient (C) between the nonwoven fabric and the bioskin (artificial skin) may be, for example, 0.0170 to 0.1000, preferably 0.0200 to 0.0900, and more preferably 0.0300 to 0.0800.

[0067] [Liquid-impregnated sheet] The present invention includes a liquid-impregnated sheet using the nonwoven fabric. The liquid-impregnated sheet includes at least the nonwoven fabric and a liquid described below, and can be suitably used in cleaning applications, beauty applications, medical applications, household applications, industrial applications, etc.

[0068] The liquid used according to these applications can be appropriately selected according to the application, and may be a solution, dispersion, emulsion, etc. having known or conventional active ingredients. The liquid may be an aqueous liquid such as water, an aqueous solution, or an aqueous emulsion, an organic solvent, an oily liquid using these as a medium, or a mixture thereof.

[0069] The impregnation amount of the liquid to be used is not particularly limited as long as a predetermined effect can be obtained, and can be appropriately selected according to the purpose. The impregnation amount of the liquid may be, for example, 100 to 1000 parts by mass, preferably 150 to 800 parts by mass, based on 100 parts by mass of the nonwoven fabric.

[0070] As the active ingredient, depending on the use, various beauty ingredients, cleaning ingredients, washing ingredients, disinfecting ingredients, medicinal ingredients, refreshing ingredients, insect repellent ingredients, coating agents, paints, finishing agents (such as varnishes, etc.) can be used, and these active ingredients may be used alone or in combination of two or more.

[0071] Also, as the active ingredient, known or commonly used active ingredients can be used, and depending on the type and use of the active ingredient, appropriate solvents (such as water, ethanol, glycerin, propylene glycol, dipropylene glycol, butylene glycol, etc.), auxiliaries (such as emulsifiers, chelating agents, pH adjusters, neutralizing agents, thickeners, lubricants, crystallization rate retardants, etc.), additives (such as ultraviolet absorbers, powders, antioxidants, preservatives, fragrances, fluorescent brighteners, antistatic agents, flame retardants, deodorants, plasticizers, colorants, etc.) can be utilized.

[0072] Beauty ingredients (ingredients for improving the body and appearance) include whitening ingredients, anti-aging (anti-oxidation, anti-wrinkle, anti-sagging) ingredients, anti-inflammatory (stimulus relief, anti-allergy) ingredients, cell activation (turnover promotion, DNA damage repair) ingredients, moisturizing ingredients, emollient ingredients, astringent ingredients, peeling ingredients, blood circulation promoting ingredients, anti-oxidation ingredients, warming ingredients, etc. Preferred beauty ingredients include arbutin, kojic acid, vitamin A, vitamin C, vitamin E, astaxanthin, resveratrol, N-acetylglucosamine, ellagic acid, tranexamic acid, linoleic acid, oxyproline, hydroxyproline, tocopherol and their derivatives, water-soluble polymers, amino acids, peptides such as EGF, sugar alcohols, saccharides, mucopolysaccharides, various plant extracts, placenta extract, capsaicin, etc.

[0073] Cleaning ingredients for the purpose of cleaning the skin include nonionic surfactants, alcohols (such as ethanol, polyhydric alcohols, etc.), glycol ethers, oils (such as mineral oil-based oils, ester-based oils, waxes, silicone-based oils, natural oils, etc.).

[0074] As cleaning components, in addition to the above-mentioned cleaning components, amphoteric surfactants, cationic surfactants, anionic surfactants, solvents, alkaline agents, etc. can be mentioned.

[0075] As disinfection components, chlorine-based disinfectants (such as chlorites like sodium chlorite, hypochlorites like sodium hypochlorite, chlorates like sodium chlorate, perchlorates like sodium perchlorate, and chlorinated cyanurates like sodium dichloroisopropylmethylphenol cyanurate, etc.), alcohols (such as ethanol, isopropanol, etc.), amphoteric surfactants, quaternary ammonium salts (such as benzalkonium chloride, benzethonium chloride, etc.), chlorhexidine, etc. can be mentioned.

[0076] As medicinal components, various medicinal components can be utilized according to the usage. For example, as medicinal components used for compresses, etc., anti-inflammatory agents, antihistamines, steroids, analgesic and anti-inflammatory agents, local anesthetics, etc. can be mentioned.

[0077] As cooling components, alcohols such as ethanol, menthol, peppermint oil, peppermint oil, camphor, thymol, spirantol, methyl salicylate, etc. can be mentioned.

[0078] As insect repellent components, eucalyptus extract, menthol, peppermint oil, diethyltoluamide, etc. can be mentioned.

[0079] For example, a beauty face mask contains beauty components and a solvent, and may contain other active ingredients, auxiliaries, additives, etc. as required. The cleansing sheet contains cleaning components and may contain other active ingredients (such as beauty components, etc.), solvents, auxiliaries, additives, etc. as required. The cleaning wiper contains cleaning components and may contain other active ingredients (such as coating agents, finishing agents, paints, etc.), solvents, auxiliaries, additives, etc. as required. The antibacterial and virus wiper contains a disinfection component, and may contain other active components (such as moisturizing components), solvents, adjuvants, additives, etc. as required. The itching suppression sheet contains a medicinal ingredient, and may contain other active ingredients (such as cooling ingredients, moisturizing ingredients), solvents, adjuvants, additives, etc. as required. The antiperspirant sheet contains a cooling ingredient, and may contain other active ingredients (such as astringent ingredients, moisturizing ingredients), solvents, adjuvants, additives, etc. as required. The insect repellent sheet contains an insect repellent ingredient, and may contain other active ingredients (such as moisturizing ingredients), solvents, adjuvants, additives, etc. as required.

[0080] In particular, the non-woven fabric of the present invention is sufficiently impregnated with the target liquid, has excellent liquid discharge properties during use, and excellent shape stability. Therefore, for example, it can be suitably used as a coating sheet (especially a wiping sheet). For example, when used as a coating sheet, it is possible to suppress the slipping of the folded non-woven fabrics, so even if the size is larger than usual, it is possible to facilitate use in a folded state. For example, in such a case, the size of one sheet of the sheet may be, for example, 200 cm 2 or more, preferably 250 cm 2 or more. The size of one sheet of the sheet can be appropriately selected according to the application. For example, in the case of skin care applications, the upper limit of the size of one sheet of the sheet may be, for example, 1000 cm 2 or so.

[0081] In addition, the liquid-impregnated sheet of the present invention utilizes water retention, liquid discharge rate, and good touch to contain the above-mentioned active ingredients and is useful as a skin care sheet used for the skin. The skin care sheet may be a so-called rubbing sheet that rubs the skin, or a so-called non-rubbing sheet that does not rub the skin.

[0082] The liquid-impregnated sheet of the present invention can be used as a non-rubbing sheet, such as a beauty sheet impregnated with beauty ingredients (e.g., beauty mask, nail care sheet, scalp care sheet, body care sheets for the back, chest, abdomen, etc., hygiene sheet, etc.), a medicinal or therapeutic sheet (itching suppression sheet, poultice, etc.).

[0083] On the other hand, by using a non-woven fabric having an appropriate compression hardness and liquid release rate (especially a non-woven fabric capable of suppressing fuzzing by friction) as a base material, the liquid-impregnated sheet of the present invention can also be suitably used as a rubbing sheet. As a rubbing sheet, it can be used as a makeup removing sheet or cleansing sheet impregnated with a wiping and cleaning component, a body washing sheet (sweat wiping sheet, antiperspirant sheet, hair and scalp wiping, buttocks wiping, hygiene sheet, etc.), an insect repellent sheet, a cooling sheet, a medicinal or therapeutic sheet (itching suppression sheet, etc.). In particular, when removing eye makeup, although the eyelid area is an extremely delicate skin area, the amount of makeup components to be removed is large due to thick eye makeup. However, the liquid-impregnated sheet of the present invention can release sufficient liquid without causing a burden on the skin, and since the ethylene-vinyl alcohol copolymer can achieve both lipophilicity and hydrophilicity, it is particularly useful as a makeup removing sheet.

Examples

[0084] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In the following examples and comparative examples, various physical properties were measured by the following methods.

[0085] 〔Basis weight and apparent density〕 According to 6.2 of JIS L 1913 "General Test Methods for Non-Woven Fabrics", the basis weight (g / m 2 ) was measured. The apparent density (g / cm 3 ) was calculated by dividing the basis weight by the thickness.

[0086] 〔Thickness〕 Referencing JIS L 1913, the thickness was measured using a thickness gauge for a circular horizontal plate with a diameter of 25.4 mm under a load of 12 g / cm 2 , and this was taken as the thickness of the non-woven fabric.

[0087] 〔Water retention capacity〕 Measurement was carried out in accordance with JIS L 1913 6.9.2 (Water retention rate). A test piece was cut out into a 10 cm square and its mass X (g) was measured. The test piece was immersed in water for 15 minutes. Then, one side of the test piece was picked up and removed from the water, and the mass Y (g) after 1 minute was measured. The water retention capacity (g) was calculated from these values using the following formula. Water retention capacity (g) = Y - X

[0088] 〔Water retention rate〕 The value obtained by dividing the water retention capacity by the mass of the test piece before immersion in water and expressing it as a percentage was taken as the water retention rate (%), and was calculated using the following formula. Water retention rate (%) = (Y - X) / X × 100

[0089] 〔Compression hardness〕 The compression hardness at 30% compression deformation was measured according to the following procedure. (1) The test sample was cut into eight pieces with a size of 5 cm square, and the mass of the eight pieces was measured. (2) The eight samples were stacked, and a mixed solution prepared by adjusting distilled water (product number 042 - 16973, manufactured by Fuji Film Wako Pure Chemical Corporation) and glycerin (glycerin P "KEN-E", manufactured by Ken-Ei Pharmaceutical Co., Ltd.) at a ratio of distilled water 5:glycerin 4 (mass ratio) was dropped from a position 2 cm higher than the sample at 0.3 cc each, and after a total of 500 mass% was dropped, the entire sheet surface was impregnated. (3) It was left standing in a sealed environment where the mixed solution did not evaporate, and left for 24 hours until the liquid spread throughout the eight pieces by capillary action. (4) After 24 hours, the sample was taken out, and referencing JIS L 1913, the thickness E (mm) was measured using a thickness gauge for a circular horizontal plate with a diameter of 25.4 mm while the eight pieces were stacked under a load of 16 g / cm 2 . (5) Subsequently, the center of the sheet is measured using a YAWASA measuring instrument Type MSES-0512-1-SL manufactured by Techno Kiban Co., Ltd. under the conditions of a probe diameter of 20.0 mm, a pushing speed of 1.0 mm / s, and a maximum load of 5.0 N to obtain the repulsive force. (6) From the obtained data, with the strain F (mm) of the sheet thickness E (mm) × 30% as the center, the stress (N) applied when the strain changes by 0.25 mm up and down from there is read respectively, and the value obtained by dividing the difference by 0.5 mm is defined as the compression hardness (N / mm) at 30% compression deformation.

[0090] 〔Liquid discharge rate〕 The liquid discharge rate at 30% compression deformation was measured by the following procedure. (1) The measurement sample is cut into 8 pieces with a size of 5 cm square, and the mass G (g) of the 8 pieces is measured. (2) The 8 samples are stacked, and a mixed solution adjusted at a ratio (mass ratio) of distilled water 5 and glycerin 4 (manufactured by Fuji Film Wako Pure Chemical Corporation, product number 042-16973 for distilled water and Ken-etsu glycerin P manufactured by Ken-ei Pharmaceutical Co., Ltd. for glycerin) is dropped from a position 2 cm higher than the sample at 0.3 cc per time for 500 mass%, and the entire surface of the sheet is impregnated. (3) The sample is left standing in a sealed environment where the mixed solution does not evaporate for 24 hours until the liquid permeates through the entire 8 pieces by capillary action. (4) After 24 hours, the sample is taken out, and referring to JIS L 1913, the thickness E (mm) when a load of 16 g / cm 2 is applied with a thickness measuring instrument for a circular horizontal plate with a diameter of 25.4 mm while the 8 pieces are stacked. (5) The sample is placed stationary on the measurement table, and absorbent cotton H (g) whose mass has been measured in advance is placed at a position 2 cm away from the sample. The pressing plate is slowly slid to the thickness E (mm) of the sample to sandwich the sample and the absorbent cotton. (6) As shown in Fig. 4, rotate the measurement table by 90 degrees to make the sample vertical. Fig. 4 is a schematic side view for explaining the state in which the liquid discharged from the sample is absorbed by the absorbent cotton in the liquid discharge rate test. The measurement table 24 after rotation holds the sample 20 and the absorbent cotton 22 vertically and successively one above the other. Since the sample 20 is disposed above the absorbent cotton 22, when the sample 20 is compressed by the movement of the pressing plate 23, the mixed liquid discharged from the sample 20 is absorbed by the absorbent cotton 22. (7) Specifically, move the pressing plate 3 at a speed of 0.2 mm / sec until the position where the sample is compressed by 30% in the thickness direction from the thickness E, and compress the sample 20 for a total of 10 seconds, and absorb the mixed liquid discharged from the sample 20 with the absorbent cotton 22. (8) Measure the mass I (g) of the absorbent cotton 22 that has absorbed the mixed liquid. Thereby, the liquid discharge rate J (%) from the sample was calculated by the following formula. Liquid discharge rate J (%) = (I - H) / (G × 5) × 100

[0091] 〔Coefficient of static friction between liquid-impregnated nonwoven fabrics〕 Using a precision universal testing machine (“Autograph AGS-D type” manufactured by Shimadzu Corporation), the frictional force was measured with reference to ASTM-D1894.

[0092] First, as shown in Figs. 5 and 6, a sample 30 cut out from the obtained nonwoven fabric with a size of 4.0 cm in the MD direction × 6.0 cm in the CD direction and a friction member 35 cut out with a size of 6.0 cm in the MD direction × 12.0 cm in the CD direction were prepared. In the sample 30 of Fig. 5, in the CD direction, a 1 cm-wide gripping portion 31a was formed from the end, and the remaining 5 cm-wide portion was the grounding portion 31b. In the friction member 35 of Fig. 6, in the CD direction, a 1 cm-wide gripping portion 35c was formed from the end, and the remaining 11 cm-wide portion was the grounding portion 35d. Further, assuming a cleansing sheet, both the sample 30 and the friction member 35 were impregnated with distilled water (product number 042-16973 manufactured by Fuji Film Wako Pure Chemical Corporation) at 400 mass%.

[0093] Next, as shown in FIGS. 7 and 8, the sample 30 was placed on the friction member 35, the gripping portion 31a of the sample 30 was gripped by the clip 36, and a test was conducted to pull the sample 30 in the direction of the arrow while applying a predetermined load from the weight 38 through the acrylic plate 37.

[0094] Specifically, in a precision universal testing machine equipped with a load cell 32, the friction member 35 was placed on the table 39, and the sample 30 was placed on the friction member 35. The sample 30 and the friction member 35 were respectively provided with gripping portions 31a and 35c in opposite directions, and these gripping portions 31a and 35c were gripped by the clip 36.

[0095] Next, an acrylic plate 37 of the same size was placed in the range of MD 4.0 cm × CD 5.0 cm (grounding portion) of the sample 30, and with a total load of 3.75 g / cm between the acrylic plate 37 and the weight 38, 2 while applying a load, the sample 30 was horizontally pulled in the CD direction at a speed of 100 mm / min by pulling the polyamide yarn 34 horizontally through the pulley 33, and the static friction coefficient was calculated from the test force obtained.

[0096] [Static Friction Coefficient between the Liquid-Impregnated Nonwoven Fabric and the Bioskin] Using a precision universal testing machine ("Autograph AGS-D type" manufactured by Shimadzu Corporation), the frictional force was measured with reference to ASTM-D1894.

[0097] First, as shown in FIG. 9, a sample 30 cut out from the obtained nonwoven fabric with a size of 4.0 cm in the MD direction × 11.0 cm in the CD direction was prepared. In the sample 30 of FIG. 9, in the CD direction, a 1 cm wide portion from the end was used as the gripping portion 31a, and the remaining 10 cm wide portion was used as the grounding portion 31b. Further, assuming a cleansing sheet, this sample was impregnated with distilled water (product number 042-16973, manufactured by Fuji Film Wako Pure Chemical Corporation) at 400 mass%.

[0098] Next, as shown in FIGS. 7 and 8, the sample 30 was placed on the friction member 35, the gripping portion 31a of the sample 30 was gripped by the clip 36, and a test was conducted to pull the sample 30 in the direction of the arrow (CD direction) while applying a predetermined load from the weight 38 via the acrylic plate 37.

[0099] In this test, (i) an artificial skin Bioskin Plate, product number P001 - 001, manufactured by VIEW LAX Co., Ltd. was used as the friction member 35, (ii) the grounding portion of the sample 30 was set to a range of MD 4.0 cm × CD 10.0 cm, and (iii) the total load of the acrylic plate 37 and the weight 38 of the same size disposed on the grounding portion was 5 g / cm 2 Except for the above, the test was conducted in the same manner as the static friction coefficient between non - woven fabrics, and the static friction coefficient was calculated.

[0100] 〔Lint length〕 Using a precision universal testing machine ("Autograph AGS - D type" manufactured by Shimadzu Corporation), the lint length was measured with reference to ASTM - D1894.

[0101] First, as shown in FIG. 10, a sample 30 cut out from the obtained non - woven fabric with a size of MD 7.0 cm × CD 4.0 cm was prepared. In the sample 30 of FIG. 10, in the MD direction, a 1 - cm - wide portion from the end was used as the gripping portion 31a, and the remaining 6 - cm - wide portion was used as the grounding portion 31b.

[0102] Next, as shown in FIGS. 7 and 8, the sample 30 was placed on the friction member 35, the gripping portion 31a of the sample 30 was gripped by the clip 36, and a test was conducted to pull the sample 30 in the direction of the arrow while applying a predetermined load from the weight 38 via the acrylic plate 37.

[0103] In this test, the test was conducted in the same manner as the static friction coefficient between sheets, except that (i) the friction member 35 was the Sankyo Chemical Co., Ltd. waterproof file #1000, and (ii) the grounded portion of the sample 30 was in the range of MD 6.0 cm × CD 4.0 cm. The sample was pulled 10 cm in the MD direction at a speed of 100 min / min in the horizontal direction.

[0104] After that, the sample was removed from the testing machine, and the sample 30 was fixed in a state of being suspended vertically with the gripping portion 31a facing upward. Among the lint that could be visually confirmed protruding from the MD-direction end of the grounded portion 31b of the sample, the lengths of 5 pieces of lint in descending order of length were measured, and the average value was taken as the lint length (mm) of the sample. Furthermore, by dividing the lint length by the thickness of the nonwoven fabric, the lint length per thickness (1-fold) of the nonwoven fabric was obtained. The thickness of the nonwoven fabric was the thickness of the nonwoven fabric when a load of 12 g / cm 2 was applied using a thickness measuring device for a circular horizontal plate with a diameter of 25.4 mm, referring to JIS L 1913.

[0105] 〔Elongation〕 Using a precision universal testing machine (Autograph AGS-D type manufactured by Shimadzu Corporation), the elongation was measured according to JIS L 1913 (General short fiber nonwoven fabric) 6.3.2 (Tensile strength and elongation test when wet). As shown in Fig. 11, with the gripping interval set to 100 mm, the sample 40 was cut out in the MD direction of 2.5 cm × CD direction of 12.0 cm. A line was drawn with an oil-based sign pen at a position 15 mm from one end in the CD direction, and another line was drawn at an interval of 90 mm. The sample 40 was placed in water at 20°C ± 2°C until it sank by its own weight, or immersed in water for 1 hour or more to absorb the saturated moisture content. Then, the sample 40 was taken out of the immersion liquid, and immediately the gripping portions 41a, 41a provided at both ends of the sample 40 were gripped as shown in Fig. 11, and a tensile stress of 2 N was instantaneously applied at a speed of 200 mm / min.

[0106] After that, the sample was removed from the testing machine, and while holding one gripping part 41a upward and suspending the sample 40 vertically, the interval K (mm) between the lines was measured. The elongation rate L (%) was calculated by the following formula. Elongation rate L (%) = K / 90 × 100 - 100

[0107] [Test on usability] (Sample) Four sheets cut into a 7 cm square size were stacked, and a mixed solution prepared by adjusting distilled water (product number 042 - 16973 manufactured by Fuji Film Wako Pure Chemical Corporation) and glycerin (glycerin P "KEN - A" manufactured by Ken - Ei Pharmaceutical Co., Ltd.) at a ratio of distilled water 5:glycerin 4 (mass ratio) was dropped by 0.3 cc each from a position 2 cm higher than the sample, and a sample impregnated throughout the sheet was prepared.

[0108] (Test by panel) Nine subjects (women in their 20s, 30s, and 40s) applied the lipstick "(Shiseido Co., Ltd.) Maquillage Dramatique Rouge N RD633" on their lips, and while sandwiching one end between the index finger and middle finger and the opposite end between the ring finger and little finger so that the CD direction of the sample was perpendicular to the finger, they wiped it horizontally twice without changing the surface while gently pressing inside the middle finger and ring finger. For each sample, evaluation was made on five items: removability, irritation to the skin, morphological stability, fluffiness, and slipperiness between sheets.

[0109] [Removability] The sensory test was carried out by the above - mentioned method, and the removability was judged in the following three levels. 〇: The degree of lipstick removal is satisfactory. △: The degree of lipstick removal is slightly unsatisfactory. ×: The degree of lipstick removal is unsatisfactory.

[0110] [Irritation to the skin] The sensory test was carried out by the above - mentioned method, and the irritation to the skin was judged in the following three levels. 〇: Little irritation. △: Slightly more irritation. ×: Much irritation.

[0111] 〔Morphological stability〕 The sensory test was carried out by the above method and judged in the following three levels according to the following criteria. After the test, the folded four - ply sheet was unfolded, measured in the CD direction, and the width spread from 15 cm before use was calculated. 〇: The spread width is within 5 mm △: The spread width exceeds 5 mm and is within 10 mm ×: The spread width exceeds 10 mm

[0112] 〔Fuzziness〕 The sensory test was carried out by the above method and judged in the following three levels according to the following criteria. After the test, the use surface was made horizontal, and the number of fibers protruding more than 3 mm from the surface was counted. 〇: 0 fibers △: 1 or more and less than 5 fibers ×: 5 or more fibers

[0113] 〔Slip resistance between sheets〕 The sensory test was carried out by the above method and judged in the following three levels according to the following criteria. The number of times the sheet did not slip during wiping while the top - most surface sheet in contact with the lips did not slip was counted. 〇: 0 times △: 1 time ×: 2 or more times

[0114] The above five items were evaluated, and the number of people with an 〇 evaluation in each item was taken as the sensory evaluation result. A: 〇 for 7 or more people B: 〇 for 4 or more and 6 or less people C: 〇 for 3 or less people

[0115] In addition, when using a non - woven fabric already impregnated with components such as liquid, it is preferable to once remove the impregnated components along the following procedure and then measure and evaluate the above physical properties. Specifically, in order to remove the components previously impregnated in the obtained non-woven fabric by immersing the non-woven fabric impregnated with components such as liquid in a cleaning solution for 2 hours, the non-woven fabric is washed. The amount of the cleaning solution is 2 L per 100 cm 2 of the area of the non-woven fabric. Also, although not particularly limited as long as the impregnated components can be removed, for example, as the cleaning solution, ion-exchanged water / neutral detergent = 95 / 5 (volume ratio) may be used. As the neutral detergent, for example, Kao Corporation's Cucute (trademark) is used, and the non-woven fabric is left standing in the liquid. Then, after immersing it in the same amount of ion-exchanged water for 2 hours to remove the cleaning solution, the non-woven fabric is air-dried (conditions: 10°C, 65% RH, 24 hours) so as not to change the shape of the non-woven fabric as much as possible, and it can be used as a measurement sample.

[0116] (Example 1) 80 parts by mass of cellulose-based fibers (regenerated cellulose fibers, "Hope" manufactured by Ohm Kenshi Co., Ltd., fineness 1.7 dtex, fiber length 40 mm), 10 parts by mass of non-adhesive core-sheath composite fibers (core-sheath composite fibers with a core made of polyethylene terephthalate and a sheath made of ethylene-vinyl alcohol copolymer (EVOH), "Sophista" manufactured by Kuraray Co., Ltd., fineness 1.7 dtex, fiber length 51 mm, core-sheath mass ratio (core 50% sheath 50%)), 10 parts by mass of adhesive core-sheath composite fibers (core-sheath composite fibers with a core made of polypropylene and a sheath made of polyethylene, manufactured by Ube Eximo Co., Ltd., fineness 1.7 dtex, fiber length 51 mm, core-sheath mass ratio (core 39% sheath 61%)) are uniformly mixed in a ratio of, and then the basis weight is 50 g / m 2A semi-random card web was prepared by a conventional method. This card web was placed on a punching drum support with an aperture ratio of 25% and a pore diameter of 0.3 mm, and continuously transferred longitudinally at a speed of 50 m / min. At the same time, high-pressure water jets were sprayed from above to perform entanglement treatment, and an entangled fiber web (non-woven fabric) was produced. In this entanglement treatment, two nozzles with orifices having a pore diameter of 0.10 mm provided at intervals of 0.6 mm along the width direction of the web were used (the distance between adjacent nozzles was 10 cm). The water pressure of the high-pressure water jet sprayed from the nozzles in the first row was 3.0 MPa, and the water pressure of the high-pressure water jet sprayed from the nozzles in the second row was 4.0 MPa. Further, it was placed on a flat support having a finer mesh and continuously transferred, and at the same time, high-pressure water jets were sprayed to perform entanglement treatment. This entanglement treatment was performed using two nozzles with orifices having a pore diameter of 0.10 mm provided at intervals of 0.6 mm along the width direction of the web, and in both cases, under the condition of a water pressure of 4.0 MPa for the high-pressure water jet. Further, it was dried at 130 °C, and the basis weight was 50.2 g / m 2 of spunlace non-woven fabric was obtained.

[0117] (Example 2·3) A spunlace non-woven fabric was obtained in the same manner as in Example 1 except that a semi-random card web having the fiber composition ratio shown in Table 1 was prepared.

[0118] (Comparative Examples 1 to 4) A spunlace non-woven fabric was obtained in the same manner as in Example 1 except that a semi-random card web having the fiber composition ratio shown in Table 1 was prepared.

[0119] (Comparative Examples 5·6) A spunlace non-woven fabric was obtained in the same manner as in Example 1 except that a semi-random card web using polyester fibers ("Tetoron" T-471, fineness 1.6 dtex, fiber length 51 mm, manufactured by Toray Industries, Inc.) instead of the non-adhesive core-sheath type composite fibers was prepared.

[0120] (Comparative Example 7) A spunlace non-woven fabric was obtained in the same manner as in Example 1 except that the drying temperature was lowered to 110 °C.

[0121] (Comparative Example 8) A spunlace nonwoven fabric was obtained in the same manner as in Example 1 except that the drying temperature was raised to 160°C.

[0122] [Table 1]

[0123] As shown in Table 1, in Comparative Example 1, although the elongation rate can be controlled by the formation of the adhesive part by the adhesive core-sheath composite fiber, the water retention amount is low because the proportion of the cellulose-based fiber is low. Regarding the compression hardness during liquid impregnation, it is too soft during compression and does not have an appropriate hardness (elasticity). In the sensory evaluation, the sheets slide against each other during wiping, and as a result, sufficient wiping performance cannot be exhibited.

[0124] In Comparative Example 2, although the elongation rate can be controlled by the formation of the adhesive part by the adhesive core-sheath composite fiber, since the adhesive part is formed in a state where the proportion of the cellulose-based fiber is high, the structure becomes too dense, and both the water retention rate and the liquid release rate become low. Furthermore, since it does not contain a non-adhesive core-sheath composite fiber having EVOH in the sheath part, the compression hardness during liquid impregnation cannot be controlled either, and it becomes too hard during compression. Also, the friction between the bioskin and the liquid-impregnated nonwoven fabric is high. In the sensory evaluation, the irritation to the skin becomes strong, and due to the low liquid release rate, the wiping performance also deteriorates.

[0125] In Comparative Example 3, since it does not contain an adhesive core-sheath composite fiber, the elongation rate cannot be controlled. Therefore, in the sensory test as well, a low evaluation is obtained for the morphological stability. However, in Comparative Example 3, the densification of the nonwoven fabric by the cellulose-based fiber somewhat alleviates the decrease in the elongation rate and also alleviates the deterioration of the liquid release rate and the decrease in the water retention rate compared to Comparative Example 2. Still, the obtained nonwoven fabric has both a low water retention rate and a low liquid release rate. In the sensory evaluation, since it does not have an adhesive part, the morphological stability is poor, the irritation to the skin becomes strong due to the decrease in the liquid release property, and the wiping performance also deteriorates.

[0126] In Comparative Example 4, since it does not contain the adhesive core-sheath composite fiber, the elongation rate becomes high and the morphological stability cannot be controlled at all. Furthermore, regarding the compression hardness during liquid impregnation, it is too soft during compression and does not have an appropriate hardness (elasticity). In the sensory evaluation, since it does not have an adhesive part, it is evaluated that the morphological stability is particularly poor.

[0127] In Comparative Examples 5 and 6, instead of the non-adhesive core-sheath composite fiber having EVOH in the sheath part, simple PET fibers are used. Therefore, in Comparative Example 5, the compression hardness (elasticity) becomes low, and as a result, although the water retention rate is high, the liquid drainage property deteriorates. Also, in Comparative Example 6, since the proportion of PET fibers is higher and the proportion of cellulose-based fibers is lower than in Comparative Example 5, the non-woven fabric cannot be densified, the compression hardness is extremely low, the liquid drainage rate is too high, and furthermore, linting occurs.

[0128] In the sensory evaluation, in Comparative Example 5, it is evaluated that the liquid drainage amount is small and there is a problem with the wiping property. In Comparative Example 6, not only is the liquid drainage amount large and it is likely to cause dripping, but also the sheets slip during wiping, and as a result, sufficient wiping property cannot be exhibited. Furthermore, it also receives a low evaluation for linting.

[0129] In Comparative Example 7, although it contains the adhesive core-sheath composite fiber, since it does not have an adhesive part, the elongation rate becomes high and the morphological stability cannot be controlled at all. Furthermore, a lot of linting also occurs, and regarding the compression hardness during liquid impregnation, it is too soft during compression and does not have an appropriate hardness (elasticity). In the sensory evaluation, since it does not have an adhesive part, not only is it evaluated that the morphological stability is particularly poor, but it also receives a low evaluation for linting.

[0130] In Comparative Example 8, not only the adhesive core-sheath composite fiber but also the non-adhesive core-sheath composite fiber has an adhesive part, resulting in too many adhesive parts, so both the water retention rate and the liquid drainage rate are low. Furthermore, the compression hardness during liquid impregnation cannot be controlled, and it becomes too hard during compression. Also, the friction between the bioskin and the liquid-impregnated nonwoven fabric is high. In the sensory evaluation, the irritation to the skin is strong, and due to the low liquid drainage rate, the wiping property is also deteriorated.

[0131] On the other hand, in Examples 1 to 3, since the adhesive part is formed in a controlled state, the elongation rate of the nonwoven fabric can be controlled to improve the morphological stability. Furthermore, while having morphological stability, the water retention rate and the liquid drainage rate can also be set within a suitable range. Also, the sheets can maintain a predetermined frictional force to suppress slippage between the sheets, and on the other hand, the friction against the bioskin can be reduced. Therefore, for example, even when folding and wiping, good wiping properties can be realized. Also, in the sensory test, favorable evaluations are obtained regarding morphological stability, irritation to the skin, wiping properties, slipperiness between the sheets, and fuzziness.

Industrial Applicability

[0132] The nonwoven fabric of the present invention is excellent in morphological stability, water retention, and liquid drainage, and thus can be suitably used as a liquid-impregnated sheet for face masks, coating sheets, wiping sheets, etc. In particular, when used after folding, the nonwoven fabrics do not easily slip and have excellent handleability, and the friction between the nonwoven fabric and the skin can be reduced. Therefore, even when using the folded sheet, it can be used comfortably.

[0133] As described above, the preferred embodiments of the present invention have been described, but various additions, changes, or deletions are possible without departing from the spirit of the present invention, and such things are also included within the scope of the present invention.

Explanation of Symbols

[0134] 10 Nonwoven fabric 11 Adhesive core-sheath composite fiber 11a Sheath part of the core-sheath composite fiber 11b Core part of the core-sheath composite fiber 12 Adhesive part 13 Cellulose-based fiber 14 Non-adhesive core-sheath composite fiber 20, 30, 40 Samples 22 Absorbent cotton 23 Pressing plate 24 Measuring table 35 Friction member 31a, 41a Gripping part of the sample 31b Grounding part of the sample 32 Load cell 33 Pulley 34 Polyamide thread 35c Gripping part of the friction member 35d Grounding part of the friction member 36 Clip 37 Acrylic plate 38 Weight 39 Table

Claims

1. A nonwoven fabric containing cellulosic fibers, adhesive sheath-core composite fibers, and non-adhesive sheath-core composite fibers, Relative to the total mass of the nonwoven fabric, The content of the adhesive core-sheath type composite fiber is 5% by mass or more and 20% by mass or less, The content of the cellulosic fibers is 45% by mass or more and less than 90% by mass, and The adhesive core-sheath type composite fiber has adhesive parts bonded at the intersections where the fibers intersect with each other, The non-adhesive core-sheath type composite fiber is a nonwoven fabric, the sheath of which contains an ethylene-vinyl alcohol copolymer.

2. 2. The nonwoven fabric according to claim 1, wherein the mass ratio of the content (T) of the cellulosic fiber to the content (N) of the non-adhesive core-sheath type composite fiber is T / N=99 / 1 to 51 / 49.

3. 3. The nonwoven fabric according to claim 1, which has an elongation percentage of 40% or less when it absorbs a saturated amount of water.

4. The nonwoven fabric according to any one of claims 1 to 3, wherein the nonwoven fabric has a compression hardness of 0.750 to 1.500 N / mm at 30% compression deformation when impregnated with a mixed solution of distilled water and glycerin (mass ratio of distilled water / glycerin = 5 / 4) in an amount of 500 mass% based on the mass of the nonwoven fabric and left for 24 hours.

5. The nonwoven fabric according to any one of claims 1 to 4, wherein when the nonwoven fabric is impregnated with a mixed liquid of distilled water and glycerin (distilled water / glycerin mass ratio = 5 / 4) in an amount of 500 mass% relative to the mass of the nonwoven fabric and left for 24 hours, the liquid release rate for 10 seconds when compressed and deformed by 30% is 7 to 14%.

6. The nonwoven fabric according to any one of claims 1 to 5, having a water retention rate of 1145% or more.

7. The nonwoven fabric according to any one of claims 1 to 6, wherein the difference (A-C) between the static friction coefficient (A) between the nonwoven fabric itself in a state where the nonwoven fabric contains 400% by mass of distilled water and the static friction coefficient (C) between the nonwoven fabric in a state where the nonwoven fabric contains 400% by mass of distilled water and bioskin (artificial skin) is 0.0170 to 0.1000.

8. The nonwoven fabric according to any one of claims 1 to 7, wherein the static friction coefficient (A) between the nonwoven fabrics in a state containing 400 mass% distilled water is 0.0550 to 0.0900.

9. The nonwoven fabric according to any one of claims 1 to 8, wherein the static friction coefficient (C) between the nonwoven fabric containing 400 mass% distilled water and bioskin (artificial skin) is 0.0450 or less.

10. The nonwoven fabric according to any one of claims 1 to 9, wherein the fluff length per unit thickness (1 unit) of the nonwoven fabric is 10 times or less.

11. A liquid-impregnated sheet comprising the nonwoven fabric according to any one of claims 1 to 10.

12. A wiping sheet comprising the nonwoven fabric according to any one of claims 1 to 10.

13. A method for producing the nonwoven fabric according to any one of claims 1 to 10, comprising the steps of: a step of forming a web having an entangled structure by performing an entanglement treatment on a web which contains cellulosic fibers, adhesive sheath-core composite fibers, and non-adhesive sheath-core composite fibers, the content of the adhesive sheath-core composite fibers being 5% by mass or more and 20% by mass or less, and the content of the cellulosic fibers being 45% by mass or more and less than 90% by mass, based on the total mass of the web; a step of forming a bonded portion between the adhesive core-sheath type composite fibers while not forming a bonded portion between the non-adhesive core-sheath type composite fibers in the web having the entangled structure.

14. The method for producing a nonwoven fabric according to claim 13, wherein the entanglement treatment is hydroentanglement.

15. 15. The nonwoven fabric according to claim 13 or 14, wherein in the step of forming the adhesive portion, heat treatment is performed at a temperature lower than the melting point of the sheath portion of the non-adhesive sheath core-type composite fiber and higher than the melting point of the sheath portion of the adhesive sheath core-type composite fiber.

Images