JP7629681B2 - Nonwoven fabric for liquid-impregnated skin covering sheet and liquid-impregnated skin covering sheet - Google Patents

Description

This disclosure relates to a nonwoven fabric constituting a liquid-impregnated skin application sheet impregnated with a liquid, particularly a cosmetic, and to a liquid-impregnated skin application sheet using the nonwoven fabric.

Various liquid-impregnated sheets have been proposed and put into practical use, which are used to cover the skin of the human body and apply a specific substance to the skin of the human body. Specific examples include liquid-impregnated skin covering sheets (face masks and keratin care sheets used on the heels, elbows, knees, etc.) impregnated with a liquid (e.g., cosmetics) containing an active ingredient. Nonwoven fabrics are generally used as the substrate for liquid-impregnated skin covering sheets. Since liquid-impregnated skin covering sheets are often used in contact with the skin for a relatively long period of time, various nonwoven fabrics have been proposed as the substrate from the standpoints of adhesion, liquid release, tactile feel, convenience, etc.

JP 2002-142861 A JP 2000-27064 A

In one aspect, the present embodiment aims to provide a nonwoven fabric for a liquid-impregnated skin covering sheet that exhibits good adhesion when impregnated with a liquid and used to cover the skin. In another aspect, the present embodiment aims to provide a liquid-impregnated skin covering sheet, particularly a face mask, in which the nonwoven fabric is impregnated with a liquid.

In the first aspect, the present embodiment provides a fiber optics fabric that includes 20% by mass to 80% by mass of chemical fibers having an official moisture regain of 1.0% to 7.0% and having at least one recess or constriction in a fiber cross section, and 20% by mass to 80% by mass of hydrophilic fibers,
The specific volume when dried is 12.0 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 .
Provided is a nonwoven fabric for liquid-impregnated skin covering sheets.

In the second aspect of the present embodiment, the fabric has an official moisture regain of 1.0% to 7.0% and contains 20% by mass to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% by mass to 80% by mass of hydrophilic fibers,
The specific volume when wet is 8.8 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 .
Provided is a nonwoven fabric for liquid-impregnated skin covering sheets.

In the third aspect, the present embodiment provides a liquid-impregnated skin application sheet obtained by impregnating the nonwoven fabric according to the first or second aspect with a liquid.

The nonwoven fabric of this embodiment exhibits good adhesion when it is impregnated with liquid and applied to the skin, making it possible to reduce or eliminate the portion of the nonwoven fabric that "floats" above the skin. This allows the liquid to be distributed over the entire surface of the covered skin.

FIG. 2 is a cross-sectional view of an example of a chemical fiber having a recess in its cross section, which is included in the nonwoven fabric of the present embodiment. FIG. 2 is a cross-sectional view of an example of a chemical fiber having a recess in its cross section, which is included in the nonwoven fabric of the present embodiment. FIG. 2 is a cross-sectional view of an example of a chemical fiber having a recess in its cross section, which is included in the nonwoven fabric of the present embodiment. FIG. 2 is a cross-sectional view of an example of a chemical fiber having a recess in its cross section, which is included in the nonwoven fabric of the present embodiment. FIG. 2 is a cross-sectional view of an example of a chemical fiber having a recess in its cross section, which is included in the nonwoven fabric of the present embodiment. 1 is an electron microscope photograph (magnification: 1,500 times) showing a cross section of an example of a chemical fiber having a recess in the fiber cross section contained in the nonwoven fabric of the present embodiment. 1 is an electron microscope photograph (magnification: 1,500 times) showing the side of an example of a chemical fiber having a recess in a fiber cross section included in the nonwoven fabric of the present embodiment. FIG. 2 is a cross-sectional view showing a method for measuring the dimensions of recesses in chemical fibers.

(How the present embodiment was arrived at)
In consideration of the retention and release of liquid, nonwoven fabrics for liquid-impregnated skin application sheets are often constructed by combining hydrophilic fibers such as rayon and hydrophobic synthetic fibers such as polyester fibers. The adhesion of liquid-impregnated skin application sheets (hereinafter also simply referred to as "sheets") made by impregnating a nonwoven fabric with liquid tends to increase as the bulkiness of the nonwoven fabric increases. In this sense, webs made by carding machines such as parallel cards (usually, nonwoven fabrics are made by subjecting the webs to a process of bonding or entangling fibers) have very good adhesion because the fibers are weakly entangled and are very bulky. However, the webs themselves are not suitable for practical use because the strength is low due to the weak entanglement of the fibers.

The inventors have also investigated methods of obtaining a bulkier nonwoven fabric by reducing the degree of entanglement between the fibers, but in the case of a combination of rayon and polyester fibers, if the degree of entanglement between the fibers is small, the strength of the nonwoven fabric is low and a sheet suitable for practical use cannot be obtained. The inventors have therefore investigated the types of fibers that make up the nonwoven fabric, and have found that by using fibers that are themselves bulky and exhibit relatively strong entanglement in a web state as fibers to be combined with hydrophilic fibers such as rayon, a nonwoven fabric that exhibits high bulkiness while having a strength sufficient for practical use can be obtained, leading to the present embodiment.

In this embodiment, the fibers used in combination with the hydrophilic fibers are, for example, one or more fibers selected from acrylic fibers, vinylon, and acetate. These fibers tend to give a bulkier nonwoven fabric compared to polyester fibers and polypropylene fibers having the same fineness and fiber length. In addition, these fibers are often provided as fibers having one or more recesses or constrictions in their fiber cross sections. Therefore, these fibers contribute to stronger entanglement of the fibers compared to ordinary polyester fibers and polypropylene fibers (wherein no recesses are observed when observed at a magnification of about 1000 to 2000 times). Therefore, if these fibers are used, a nonwoven fabric with relatively high strength can be obtained, for example, even if the pressure of the fluid is reduced and the specific volume of the nonwoven fabric is increased when producing a nonwoven fabric by high-pressure fluid flow processing. Furthermore, it has also been found that these fibers have a function of improving the liquid absorption of the nonwoven fabric because their official moisture regain is higher than that of hydrophobic synthetic fibers such as polyester and polypropylene.

The use of a nonwoven fabric containing acrylic fibers in a face mask is described, for example, in the above-mentioned Patent Document 1. Patent Document 1 describes an example in which a nonwoven fabric having a basis weight of 80 g/ ^m2 and a thickness of 0.4 mm (specific volume 5 ^cm3 /g) was produced as a face pack sheet by mixing 30% by mass of 1.7 dtex acrylic fibers and 70% by mass of 1.7 dtex rayon fibers (paragraphs 0076 and 0083, Table 2). According to the study by the present inventors, it was found that this nonwoven fabric has poor adhesion due to its small specific volume.

In addition, the above-mentioned Patent Document 2 discloses a textile product consisting of a nonwoven fabric containing 5 wt% or more of acrylic fibers, 10 wt% or more of acrylate fibers with Na or Ca carboxyl groups, or 50 wt% or more of rayon, and having a basis weight of 150 g/m2 or ^less , and explains that this textile product can be used for cosmetics. In the same patent document, the acrylic fibers are used to provide a warm touch (paragraph 0007), and there is no teaching or suggestion that the use of acrylic fibers can increase the specific volume, and thereby improve the adhesion of the nonwoven fabric to the skin. In addition, all of the nonwoven fabrics in the examples described in the patent document contain heat-fusible fibers and are obtained by the water punch method and the hot air heat fusion method, so their specific volumes are not very large and it is not considered that they show good adhesion.

The liquid-impregnated nonwoven fabric for skin application sheet of the present embodiment is
The fabric has an official moisture regain of 1.0% to 7.0% and contains 20% to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% to 80% by mass of hydrophilic fibers,
The specific volume when dried is 12.0 ^cm3 /g or more,
It is a nonwoven fabric with a basis weight of 20 to 55 g/ ^m2 .
Hereinafter, the fibers constituting the nonwoven fabric of this embodiment will first be described.

(Chemical fiber A)
The nonwoven fabric of this embodiment contains a chemical fiber (hereinafter, for convenience, referred to as "chemical fiber A") that has an official moisture regain of 1.0% to 7.0% and has at least one recess or constriction in its fiber cross section.
The official moisture regain is shown in JIS L0105 (2006). If the official moisture regain is unknown, the value calculated from the following formula shall be used as the official moisture regain.
Official moisture content (%) = [(W-W')/W'] x 100
Here, W means the mass (g) of the fiber in an environment of 20° C. and 65% RH humidity, and W′ means the mass (g) of the fiber when completely dry. The mass of the fiber in an environment of 20° C. and 65% RH humidity means the mass of the fiber when it is left in an environment of 20° C. and 65% RH humidity and reaches a certain mass, and the mass of the fiber when completely dry means the mass of the fiber when it is left in a dryer set at 105° C. and reaches a certain mass.

Compared to polyester fibers and polypropylene fibers, chemical fiber A has a high official moisture regain and a high affinity for water. Therefore, a nonwoven fabric containing chemical fiber A exhibits higher liquid absorption. If the official moisture regain of chemical fiber A is less than 1.0%, the liquid absorption of the nonwoven fabric may decrease, and if it exceeds 7.0%, the bulk of the nonwoven fabric may decrease when impregnated with liquid, resulting in a small specific volume. The official moisture regain of chemical fiber A may be, for example, 1.5% to 6.5%, particularly 1.8% to 5.0%, and more particularly 1.9% to 3.0%.

Chemical fiber A has at least one recess or constriction in its fiber cross section. Here, the fiber cross section refers to a surface obtained by cutting the fiber in a direction perpendicular to its length, and can also be called a "transverse section." The recess may be in a "L" shape. The "L"-shaped recess may be a valley-like shape with a linear bottom surface. In addition, the "L"-shaped recess may have two curved lines extending to the bottom surface when the cross section of the fiber is observed. Chemical fiber A having a recess in its fiber cross section may have a linear portion formed by the bottoms of the recesses being connected in the longitudinal direction when the side surface is observed. In this embodiment, the chemical fiber may have multiple recesses in the fiber cross section, and multiple linear portions may be observed on the side surface of the fiber (Figures 1 and 2).

The depression or constriction may be of a size that can be seen, for example, when the fiber cross section is observed at a magnification of about 1000 to 2000 times. For example, as shown in FIG. 7, the depression or constriction may have a size such that the distance d between the straight line m tangent to the outline of the fiber cross section forming the depression or constriction and the bottom b of the depression or constriction is, for example, 0.1 μm to 10 μm, particularly 0.5 μm to 1.5 μm. The depression or constriction formed in the fiber cross section may be continuous in the longitudinal direction when the fiber side is observed.

Chemical fiber A may also have many fine recesses in its fiber cross section. Chemical fibers having such recesses in their fiber cross section may have fine wrinkled recesses when the fiber side surface is observed under an electron microscope at a magnification of about 1000 to 2000 times, and the fine wrinkled recesses observed on the fiber side surface may be discontinuous in the longitudinal direction (Figure 6 (b)). Alternatively, the fine recesses may be continuous in the longitudinal direction.

Chemical fiber A may also have many fine recesses in its fiber cross section and one or more large recesses or constrictions overall. Alternatively, chemical fiber A may be provided as a mixture of fibers having many fine recesses in its fiber cross section and one or more large recesses or constrictions overall (for example, fibers marked with a in FIG. 6(a)) and fibers having only many fine recesses in their fiber cross section (for example, fibers marked with b in FIG. 6(a)). Note that in FIG. 6(a), the existence of fine recesses is difficult to confirm because the outline of the fiber cross section is distorted when the fiber is cut, but since fine wrinkled recesses are formed on the side (FIG. 6(b)), it is determined that the fiber cross section has many fine recesses.

A fiber cross section having at least one recess or constriction is, for example, a fiber having a cross section and side surface as shown in Figures 1 to 6. Because chemical fiber A has such a fiber cross section and side surface, it is easier to provide stronger intertwining of fibers compared to fibers whose cross section has a smooth outer periphery (such as commonly used polyester fibers and polypropylene fibers). Therefore, a nonwoven fabric containing chemical fiber A has relatively high strength even when it is made to have a high specific volume.

Specific examples of chemical fiber A include acrylic fiber, vinylon, acetate, and triacetate. All of these fibers are chemical fibers and are produced by dry spinning or wet spinning. These fibers are generally provided in a form in which the fiber cross section has a depression or constriction. In particular, acrylic fiber is preferably used because it is easy to give a bulky nonwoven fabric and has a soft feel.

The acrylic fibers, vinylon, acetate, and triacetate used as chemical fiber A may be selected from those commonly used, so long as they have the above-mentioned range of official moisture regain and the above-mentioned specific fiber cross section. Examples of acrylic fibers that can be used as chemical fiber A include Bonnell (product name) manufactured by Mitsubishi Chemical Corporation and Toraylon (product name) manufactured by Toray Industries, Inc. Examples of vinylon that can be used as chemical fiber A include Vinylon (product name) manufactured by Kuraray Co., Ltd.

Chemical fiber A is not limited to acrylic, vinylon, acetate, and triacetate, and may be other chemical fibers (synthetic fibers, regenerated fibers) as long as it has the above-mentioned range of official moisture regain and the above-mentioned specific fiber cross section. For example, chemical fiber A may be a chemical fiber made of a polyamide resin such as nylon 6, nylon 12, or nylon 66, and may have at least one recess or constriction in the fiber cross section. Fibers made of polyamide resin produced by the melt spinning method can have at least one recess or constriction in the fiber cross section by appropriately selecting the shape of the spinneret.

The fineness of the chemical fiber A may be, for example, about 0.6 dtex to 4.0 dtex, particularly about 0.6 dtex to 3.3 dtex, and more particularly about 0.8 dtex to 2.0 dtex. Chemical fiber A with a fineness within this range is suitable for ensuring the flexibility of the nonwoven fabric. If the fineness of the chemical fiber A is too small, the carding ability during the production of the fiber web may deteriorate, the productivity of the nonwoven fabric may decrease, and the strength of the obtained nonwoven fabric may become low. If the fineness of the chemical fiber A is too large, the nonwoven fabric may become coarse and the touch may deteriorate. Furthermore, if the fineness of the chemical fiber A is too large, capillary phenomenon may not occur easily, and the liquid absorption ability may decrease.

The fiber length of chemical fiber A may be appropriately selected depending on the manufacturing method of the nonwoven fabric, etc. For example, when a carded web is produced to manufacture a nonwoven fabric, chemical fiber A may be a staple fiber. When chemical fiber A is a staple fiber, its fiber length may be, for example, 20 mm to 80 mm, particularly 28 mm to 75 mm, and more particularly 30 mm to 65 mm. Alternatively, when an air-laid web is produced to manufacture a nonwoven fabric, chemical fiber A may have a fiber length of 1 mm to 50 mm, particularly 5 mm to 30 mm. When a wet-laid papermaking web is produced to manufacture a nonwoven fabric, chemical fiber A may have a fiber length of 0.5 mm to 20 mm, particularly 1 mm to 10 mm.

(hydrophilic fiber)
The nonwoven fabric of this embodiment includes hydrophilic fibers. The hydrophilic fibers serve to retain the liquid impregnated in the nonwoven fabric. The hydrophilic fibers are fibers having a higher nominal moisture regain than the chemical fiber A, specifically, a nominal moisture regain of more than 7%, particularly a nominal moisture regain of 8.5% or more, and more particularly a nominal moisture regain of 11.0% or more. The nominal moisture regain of the hydrophilic fibers may be 15.0% or less, particularly 14.0% or less, and more particularly 12.0% or less.

Specific examples of hydrophilic fibers include natural fibers such as pulp, cotton, hemp, silk, and wool; regenerated fibers such as viscose rayon, cupra, and solvent-spun cellulose fibers; and synthetic fibers that have hydrophilic properties, or synthetic fibers with low hydrophilic properties (synthetic fibers with an official moisture regain of less than 7%) that have been subjected to a hydrophilization treatment to improve their hydrophilicity. Examples of hydrophilization treatments include corona discharge treatment, sulfonation treatment, graft polymerization treatment, kneading a hydrophilizing agent into the fiber, and applying a durable oil agent.

The hydrophilic fibers are preferably cellulosic fibers. More specifically, cellulosic fibers are (1) regenerated fibers such as viscose rayon, cupra, and solvent-spun cellulose fibers (e.g., lentigned lyocell (registered trademark) and Tencel (registered trademark)), (2) pulps such as mechanical pulp, regenerated pulp, and chemical pulp, and (3) natural plant fibers such as cotton and hemp.

Among regenerated fibers, viscose rayon is preferred because it has a proven track record of use in cosmetic puffs and wet sheets that come into contact with human skin, is widely used in face masks, and is relatively inexpensive.

Of the natural plant fibers, cotton has a long history of use as a natural material and is widely used as a material for clothing and sanitary materials, giving the general consumer the impression that it is gentle on the skin, pleasant to the touch, and safe. Therefore, by using cotton, it is possible to provide products that are more likely to be accepted by consumers. When using cotton, any cotton commonly used in nonwoven fabric manufacturing can be used. Specifically, cotton with a fiber length (average fiber length) of about 20 to 60 mm can be used. Multiple cottons with different fiber lengths and types may be used.

The fineness of the hydrophilic fibers may be, for example, about 0.6 dtex to 5.6 dtex, particularly about 0.6 dtex to 3.3 dtex, and more particularly about 0.9 dtex to 2.2 dtex. Hydrophilic fibers with fineness within this range are suitable for ensuring the flexibility of the nonwoven fabric. If the fineness of the hydrophilic fibers is too small, the carding ability during the production of the fiber web may deteriorate, the productivity of the nonwoven fabric may decrease, and the strength of the obtained nonwoven fabric may become low. If the fineness of the hydrophilic fibers is too large, the nonwoven fabric may become coarse and the touch may deteriorate. Furthermore, if the fineness of the hydrophilic fibers is too large, capillary phenomenon is unlikely to occur, and the liquid absorption ability may decrease.

The fiber length of the hydrophilic fibers may be appropriately selected depending on the manufacturing method of the nonwoven fabric, etc. Examples of fiber lengths depending on the manufacturing method of the nonwoven fabric are as described for chemical fiber A. The fiber length of the hydrophilic fibers may be the same as or different from the fiber length of chemical fiber A.

(Other fibers)
The nonwoven fabric of this embodiment may contain other fibers than the chemical fiber A and the hydrophilic fiber. The other fibers may be, for example, chemical fibers with a standard moisture regain of less than 1.0%. A nonwoven fabric containing such chemical fibers has improved liquid release properties, and when used by applying it to the skin, for example, it makes it easier to transfer liquid to the skin. Such chemical fibers may be fibers made of a hydrophobic thermoplastic resin, for example, fibers made of polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and copolymers thereof, polypropylene, polyethylene (including high-density polyethylene, low-density polyethylene, linear low-density polyethylene, etc.), polybutene-1, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer.

Alternatively, the other fibers may be chemical fiber A or hydrophilic fibers whose surfaces have been treated to give them hydrophobicity (hydrophobization treatment) to make the official moisture regain less than 1.0%. For example, the other fibers may be recycled fibers whose surfaces have been treated with a hydrophobizing agent, or fibers made of polyamide resins such as nylon 6, nylon 12, and nylon 66 whose surfaces have been treated with a hydrophobizing agent.

When the other fibers are fibers made of a hydrophobic thermoplastic resin, the other fibers may be single fibers or composite fibers. The composite fibers may be, for example, sheath-core composite fibers or islands-in-the-sea composite fibers in which a hydrophobic thermoplastic resin or a thermoplastic resin that has been subjected to a hydrophobic treatment is arranged to form the fiber surface. Alternatively, the composite fibers may be fibers in which the fiber surface is formed by multiple hydrophobic thermoplastic resins, for example, split composite fibers.

When the other fiber is a composite fiber made of two or more thermoplastic resins, examples of the combination of two or more resins include a polyethylene resin/polyester resin and a polyethylene resin/polypropylene resin. Specifically, examples of the combination of two or more resins include high-density polyethylene/polyethylene terephthalate, low-density polyethylene/polyethylene terephthalate, linear low-density polyethylene/polyethylene terephthalate, ethylene-propylene copolymer/polyethylene terephthalate, polypropylene/polyethylene terephthalate, high-density polyethylene/polytrimethylene terephthalate, low-density polyethylene/polytrimethylene terephthalate, linear low-density polyethylene/polytrimethylene terephthalate, ethylene-propylene copolymer/polytrimethylene terephthalate, polypropylene/polytrimethylene terephthalate, high-density polyethylene/polypropylene, linear low-density polyethylene/polypropylene, etc.

The thermoplastic resins exemplified as components of the single fiber or composite fiber may contain other components as long as they contain 50% by mass or more of the specifically indicated thermoplastic resin. The specifically indicated thermoplastic resin may be contained in an amount of 80% by mass or more, or 90% by mass or more, or the components may essentially consist of the specifically indicated thermoplastic resin. The term "essentially" is used here in consideration of the fact that thermoplastic resins usually contain various additives, etc. For example, in the combination of high density polyethylene/polyethylene terephthalate, the "high density polyethylene" may contain other thermoplastic resins and additives, etc., so long as it contains 50% by mass or more of high density polyethylene.

The other fibers may include polyester monofilaments in particular. When such monofilaments are included as other fibers, the fibers may have good entanglement when the nonwoven fabric is produced. As described above, polyester monofilaments are fibers that contain 50% or more by mass of polyester, and may consist essentially of polyester.

The fineness of the other fibers may be about 0.6 dtex to 5.6 dtex, particularly about 0.6 dtex to 3.3 dtex, and more particularly about 0.9 dtex to 2.2 dtex. If the fineness of the other fibers is within this range, the nonwoven fabric can be made flexible. If the fineness of the other fibers is too small, the carding ability when producing the fiber web may deteriorate, the productivity of the nonwoven fabric may decrease, and the strength of the obtained nonwoven fabric may be low. If the fineness of the other fibers is too large, the nonwoven fabric may become coarse and the touch may be deteriorated. Furthermore, if the fineness of the other fibers is too large, capillary phenomenon is unlikely to occur, and the liquid absorption ability may decrease.

The fiber length of the other fibers may be appropriately selected depending on the manufacturing method of the nonwoven fabric, etc. Examples of fiber lengths depending on the manufacturing method of the nonwoven fabric are as described for chemical fiber A. The fiber length of the other fibers may be different from the fiber length of both chemical fiber A and the hydrophilic fiber, and may be the same as the fiber length of either or both of chemical fiber A and the hydrophilic fiber.

(Configuration of nonwoven fabric)
The nonwoven fabric of this embodiment includes chemical fiber A and hydrophilic fiber. Chemical fiber A allows the nonwoven fabric to have a relatively large strength even when manufactured to have a relatively large specific volume. The hydrophilic fiber ensures the liquid retention of the nonwoven fabric, and the liquid impregnated in the nonwoven fabric remains in the nonwoven fabric, creating a state in which the skin is sufficiently wetted with the liquid. Therefore, according to the nonwoven fabric of this embodiment, the use of chemical fiber A realizes a high specific volume and improves adhesion to the skin, and the use of hydrophilic fiber makes it easier for the liquid to remain on the skin, and the surface tension of the liquid can be used to improve adhesion to the skin.

The nonwoven fabric of this embodiment contains 20% to 80% by mass of chemical fiber A and 20% to 80% by mass of hydrophilic fiber. If the proportion of chemical fiber A is less than 20% by mass, the effect of including chemical fiber A may not be obtained, and if the proportion of chemical fiber A exceeds 80% by mass, the proportion of hydrophilic fiber becomes small and the liquid retention of the nonwoven fabric decreases. If the proportion of hydrophilic fiber is less than 20% by mass, the liquid retention of the nonwoven fabric also decreases, and if the proportion of hydrophilic fiber exceeds 80% by mass, the proportion of chemical fiber A becomes small and the effect of including chemical fiber A may not be obtained.

The proportion of chemical fiber A may be in particular 25% to 70% by mass, more in particular 35% to 60% by mass. The proportion of hydrophilic fiber may be in particular 25% to 70% by mass, more in particular 40% to 60% by mass.

When the nonwoven fabric of this embodiment contains other fibers, the proportion of the other fibers may be 60% by mass or less of the nonwoven fabric. If the proportion of the other fibers exceeds 60% by mass, the proportion of chemical fiber A and/or hydrophilic fibers will be small, and the effects of including these fibers may not be obtained. The proportion of the other fibers may particularly be 50% by mass or less, more particularly 35% by mass or less, and even more particularly 30% by mass or less. The proportion of the other fibers may be, for example, 0% by mass or more, particularly 10% by mass or more, and more particularly 20% by mass or more.

The nonwoven fabric of this embodiment may have a laminated structure as long as it contains the chemical fiber A and the hydrophilic fiber in the above-mentioned predetermined ratio when the mass of the entire nonwoven fabric is taken as 100% by mass. For example, the nonwoven fabric of this embodiment may be composed of a fiber layer (conveniently called "first fiber layer") made of the chemical fiber A and the hydrophilic fiber, and a fiber layer (conveniently called "second fiber layer") made of other fibers. In this case, the nonwoven fabric may have, for example, a first/second two-layer structure, or a first/second/first three-layer structure. The second fiber layer may be a spunbonded nonwoven fabric, meltblown nonwoven fabric, net-like material, wet-laid nonwoven fabric, or a nonwoven fabric (for example, a thermally bonded nonwoven fabric) made of other fibers. The first fiber layer may further contain other fibers.
Alternatively, the nonwoven fabric of this embodiment may be composed of a plurality of fiber layers each having a different mixing ratio of chemical fiber A and hydrophilic fiber.

The nonwoven fabric of this embodiment may have a single layer structure. The single layer nonwoven fabric is provided as a nonwoven fabric having a relatively uniform texture even when the basis weight is relatively small, such as 20 to 55 g/ ^m2 .

In the nonwoven fabric of this embodiment, the manner in which the fibers are integrated is not particularly limited. The fibers may be integrated by being entangled by a high-pressure fluid flow entangling method or a needle punch method, or may be integrated by being bonded to each other. The fibers may be bonded to each other by making at least one component of at least one type of fiber constituting the nonwoven fabric function as an adhesive component. In this case, the component that functions as an adhesive component may be melted or softened by heating (thermal bonding), or the fibers may be bonded to each other by irradiation with an electron beam or the like, or ultrasonic welding. Alternatively, the fibers may be bonded to each other by applying a binder (adhesive).

In this embodiment, the fibers may be integrated by intertwining and not bonded to each other. When the fibers are bonded to each other, the bond points between the fibers are generally harder than other parts, and the bond points may irritate the skin. Furthermore, the presence of bond points may cause the texture of the nonwoven fabric to become stiff.

The basis weight of the entire nonwoven fabric of this embodiment is 20 g/m ² to 55 g/m ² , and is appropriately selected from this range in consideration of the amount of liquid impregnated, etc., depending on the part of the skin to be covered, etc. The basis weight of the nonwoven fabric may be particularly 30 g/m ² to 55 g/m ² , more particularly 40 g/m ² to 50 g/m ^2. If the basis weight is too small, the amount of liquid that can be impregnated into the nonwoven fabric is reduced, and it may not be possible to supply a predetermined amount of liquid to the skin. If the basis weight is too large, the internal space is reduced, the specific volume is likely to be small, and the adhesion is reduced. In addition, the larger the basis weight, the greater the bending resistance is likely to be. If the bending resistance is large, it is difficult to make the sheet conform to the curved surface of the skin, and the sheet may partially lift up, making it difficult for the entire sheet to evenly cover the skin. In addition, if the basis weight is too large, the number of sheets that can be accommodated in one packaging bag or packaging container is reduced.

The thickness of the entire nonwoven fabric may be, for example, 0.40 mm or more, particularly 0.60 mm or more, more particularly 0.75 mm or more, when a load of 294 Pa is applied per 1 ^cm2 of the nonwoven fabric in a dry state. The thickness of the entire nonwoven fabric is, for example, 2.00 mm or less, particularly 1.50 mm or less, more particularly 1.00 mm or less. The thickness of the entire nonwoven fabric may be, for example, 0.30 mm or more, particularly 0.45 mm or more, more particularly 0.55 mm or more, when a load of 1.96 kPa is applied per 1 ^cm2 of the nonwoven fabric in a dry state. The thickness of the entire nonwoven fabric may be, for example, 1.5 mm or less, particularly 1.0 mm or less, more particularly 0.70 mm or less. If the thickness of the entire nonwoven fabric is too small, the amount of liquid that can be impregnated into the nonwoven fabric is reduced, and a predetermined amount of liquid may not be supplied to the skin. If the overall thickness of the nonwoven fabric is too large, it may be difficult to fit the sheet to the curved surface of the skin, and the sheet may float in parts, making it difficult to evenly cover the skin with the entire sheet.

The thickness of the entire nonwoven fabric may be, for example, 0.10 mm or more, particularly 0.30 mm or more, more particularly 0.40 mm or more, when a load of 294 Pa is applied per 1 ^cm2 of the nonwoven fabric when wet. The thickness of the entire nonwoven fabric may be, for example, 1.50 mm or less, particularly 1.00 mm or less, more particularly 0.70 mm or less. The thickness of the entire nonwoven fabric may be, for example, 0.10 mm or more, particularly 0.25 mm or more, more particularly 0.35 mm or more, when a load of 1.96 kPa is applied per 1 ^cm2 of the nonwoven fabric when wet. The thickness of the entire nonwoven fabric may be, for example, 1.00 mm or less, particularly 0.80 mm or less, more particularly 0.65 mm or less. The problems when the thickness of the nonwoven fabric when wet is too small or too large are the same as those when dry. The "wet thickness" refers to the thickness measured when 100 parts by weight of the nonwoven fabric is impregnated with 1,000 parts by weight of distilled water.

The nonwoven fabric of this embodiment has a specific volume of 12.0 cm ³ /g or more when a load of 1.96 kPa is applied per 1 cm ² of nonwoven fabric when dry. A nonwoven fabric having a specific volume in this range exhibits good adhesion when impregnated with liquid. This is because a nonwoven fabric with a specific volume in this range has a space inside in which fibers can easily move, and the movement of the fibers improves the ability to follow the skin and provides high adhesion. The specific volume when dry may be particularly 12.2 cm ³ /g or more, more particularly 13.0 cm ³ /g or more. The specific volume when dry may be, for example, 18.0 cm ³ /g or less, particularly 15.0 cm ³ /g or less, more particularly 14.0 cm ³ /g or less. If the specific volume is too large, the nonwoven fabric may become thick and the sheet may be difficult to fit to the curved surface of the skin, may be difficult to handle, and may be difficult to retain liquid.

The nonwoven fabric of this embodiment has a specific volume of 8.8 ^cm3 /g or more when wetted under a load of 1.96 kPa per ^cm2 of nonwoven fabric. A nonwoven fabric having a specific volume in this range exhibits good adhesion when impregnated with a liquid. The specific volume when wetted may be particularly 9.5 ^cm3 /g or more, more particularly 10.0 ^cm3 /g or more. The specific volume when wetted may be, for example, 13.0 ^cm3 /g or less, particularly 12.0 ^cm3 /g or less, more particularly 11.0 ^cm3 /g or less. The problems when the specific volume when wetted is too large are the same as those when the specific volume when dry is large.

Next, a method for producing the nonwoven fabric of this embodiment will be described.
When the nonwoven fabric of this embodiment has a single-layer structure, it can be produced by mixing chemical fiber A, hydrophilic fiber, and other fibers as necessary to prepare a fiber web, and subjecting the web to a process for integrating the fibers, which may include a process for entangling the fibers, a thermal bonding process, a bonding process using a solvent-based adhesive, a bonding process using a hot-melt resin, a bonding process using irradiation with an electron beam, and an ultrasonic welding process.

The fiber web may be any one selected from, for example, parallel webs, cross webs, card webs such as semi-random webs and random webs, air-laid webs, and wet-laid paper webs. The fiber web is preferably a parallel web. A parallel web has high productivity and is likely to give a nonwoven fabric that is bulky and has a large specific volume. In addition, since the use of a parallel web makes it easy to obtain a soft nonwoven fabric, the liquid-impregnated skin application sheet produced using this is also likely to be soft and have an excellent texture.

The nonwoven fabric of the present invention may be manufactured by integrating the fibers together through a process for entangling the fibers, thereby obtaining a nonwoven fabric with a good feel without any adhesive points. The process for entangling the fibers is, for example, a needle punch process or a high-pressure fluid flow (particularly a water flow) entanglement process. In the high-pressure fluid flow process, the high-pressure fluid is, for example, a high-pressure gas such as compressed air, or a high-pressure liquid such as high-pressure water. In the manufacture of nonwoven fabric, a water flow entanglement process using high-pressure water as the high-pressure fluid is often used, and in this embodiment, the water flow entanglement process is preferably used from the viewpoint of ease of implementation. Below, a manufacturing method in which high-pressure water (hereinafter also simply referred to as "water flow") is used as the high-pressure fluid is described.

The hydroentanglement treatment is carried out by placing the fiber web on a support and spraying a columnar water stream onto it. For example, the support is preferably a plain weave support of 80 mesh or more and 100 mesh or less. The hydroentanglement treatment may be carried out by spraying a water stream with a water pressure of 1 MPa or more and 15 MPa or less onto the front and back surfaces of the fiber web 1 to 5 times each from a nozzle having orifices with a hole diameter of 0.05 mm or more and 0.5 mm or less, spaced 0.3 mm or more and 1.5 mm or less. The water pressure is preferably 1 MPa or more and 10 MPa or less, and more preferably 1 MPa or more and 7 MPa or less.

The nonwoven fabric obtained by the hydroentanglement treatment is then subjected to a drying treatment. The drying treatment may be carried out, for example, using a hot air penetration type heat treatment machine (also called an air-through type heat processing machine), a hot air blowing type heat treatment machine, or an infrared type heat treatment machine.

When the nonwoven fabric of this embodiment is a laminated nonwoven fabric consisting of multiple fiber layers, fiber webs constituting each fiber layer are prepared, the fiber webs are laminated, and a process for integrating the fiber webs and the fibers with each other is performed. Even when manufacturing a laminated nonwoven fabric, the process for integrating the fiber webs and the fibers with each other may be a process for entangling the fibers, particularly a high-pressure fluid flow entangling process, or any of the adhesive processes exemplified above.

(Liquid-impregnated skin covering sheet)
The nonwoven fabric of this embodiment is impregnated with a liquid to form a liquid-impregnated skin covering sheet for covering the skin of a human or animal. The liquid to be impregnated and the amount of impregnation are appropriately selected depending on the application. When the sheet is provided as a liquid-impregnated skin covering sheet for humans, such as a face mask for humans, a keratin care sheet, and a décolleté sheet, the liquid (e.g., a cosmetic) containing an active ingredient may be impregnated in an amount of 600 parts by mass or more and 2500 parts by mass or less, particularly 600 parts by mass or more and 1500 parts by mass or less, and more particularly 700 parts by mass or more and 1500 parts by mass or less, relative to 100 parts by mass of the nonwoven fabric. Examples of the active ingredient include, but are not limited to, moisturizing ingredients, keratin softening ingredients, antiperspirant ingredients, fragrance ingredients, whitening ingredients, blood circulation promoting ingredients, UV protection ingredients, and slimming ingredients.

The face mask is provided in a shape suitable for covering the face, and further in a form in which, for example, openings or cutouts are provided by punching as necessary in areas corresponding to the eyes, nose, and mouth. Alternatively, the face mask may be shaped to cover only a portion of the face (e.g., the eyes, mouth, nose, or cheeks). Alternatively, the face mask may be provided as a set consisting of a sheet covering the area around the eyes and a sheet covering the area around the mouth, or as a set of sheets separately covering three or more areas.

The keratin care sheet is a skin covering sheet used on the heels, elbows, knees, etc., where the keratin is thick and prone to hardening. By impregnating it with a liquid containing a keratin softening component and a moisturizing component, the sheet exhibits the effect of promoting moisturization and softening of the keratin, and promoting the removal of excess keratin. The nonwoven fabric of this embodiment can be used as a substrate in keratin care sheets that exhibit either of these effects and efficacy. A keratin care sheet, for example a keratin care sheet for the heel, is provided in a form having cuts and/or notches and/or openings punched out of parts of the sheet so that the sheet can easily conform to the curve of the heel when applied.

Alternatively, the liquid-impregnated skin covering sheet may be used as a cleansing sheet containing a cleansing component as an active ingredient. The cleansing sheet may be used, for example, by adhering it to the part (skin) from which dirt (makeup) is to be removed, keeping it attached for a while so that the cleansing component blends with the makeup, and then wiping off the makeup. Like face masks, cleansing sheets can be said to be a type of liquid-impregnated skin covering sheet for personal use. However, unlike face masks used for the purpose of allowing active ingredients to act on the skin, the cleansing sheet is applied to the skin to blend with the makeup, so the time the cleansing sheet is applied to the skin is generally shorter than that of a face mask. When used as a cleansing sheet, the nonwoven fabric may be impregnated with a liquid (e.g., a cosmetic) containing an active ingredient in an amount of 100 to 700 parts by weight, more particularly 200 to 600 parts by weight, per 100 parts by weight of the nonwoven fabric.

The liquid-impregnated skin covering sheet may be a moisturizing sheet impregnated with a liquid containing a moisturizing ingredient or other active ingredient, which is used to moisturize or otherwise care for any part of the body (e.g., the neck, the back of the hand, or the area from the neck to the chest (also called the décolleté)). Alternatively, the liquid-impregnated skin covering sheet may be a slimming sheet impregnated with a liquid containing a slimming ingredient. The slimming sheet is used, for example, by attaching it to the thighs or abdomen.

The liquid-impregnated skin application sheet may be provided in a state where the nonwoven fabric substrate is folded. The folding may be performed only in one direction of the nonwoven fabric, or may be performed once or more in each of different directions of the nonwoven fabric. For example, the liquid-impregnated nonwoven fabric may be provided by folding it once or more in a direction parallel to the longitudinal direction (i.e., so that the folds are parallel to the longitudinal direction) and once or more in a direction parallel to the lateral direction (i.e., so that the folds are parallel to the lateral direction).

The liquid-impregnated skin dressing sheet is flexible and exhibits good adhesion to the skin because the nonwoven fabric base material contains chemical fiber A, which gives the sheet a relatively large specific volume. In addition, the chemical fiber A contained in the nonwoven fabric of this embodiment has an official moisture regain of 1.0% to 7.0%, which gives the sheet good liquid absorption and allows the sheet to be uniformly impregnated with liquid.

The liquid-impregnated skin application sheet may be provided by storing a plurality of sheets in one packaging bag or container. For such products, it may be desired to store a large number of sheets in one packaging bag or container, and the nonwoven fabric of this embodiment meets such a demand since it has a comparatively small basis weight of 20 to 55 g/ ^m2 and a comparatively thin thickness.

The present embodiment will now be described with reference to examples.
The following fibers were prepared for use in this example.
Acrylic fiber: wet-spun acrylic fiber (trade name: Bonnell, manufactured by Mitsubishi Chemical Corporation) with a fineness of 1.0 dtex and a fiber length of 44 mm, mainly made of acrylonitrile. The official moisture regain was 2.0%. As shown in FIG. 6(a) (electron microscope photograph at 1500 times), the fiber cross section had a circular or elliptical shape, and some fibers had large recesses or constrictions. As shown in FIG. 6(b) (electron microscope photograph at 1500 times), the fiber side had fine wrinkled recesses and many discontinuous recesses in the length direction, which confirmed that the fiber cross section had many small recesses. The large recesses or constrictions had a size such that the distance d between the straight line m tangent to the outline of the fiber cross section and the bottom b of the recesses or constrictions was 0.5 μm to 1.5 μm.
Rayon fiber: Viscose rayon having a fiber size of 1.7 dtex, a fiber length of 40 mm, and a chrysanthemum-shaped fiber cross section (product name: Corona CD, manufactured by Daiwabo Rayon Co., Ltd.). The official moisture regain was 11.0%.
PET fiber: a single fiber made of polyethylene terephthalate having a fineness of 1.45 dtex, a fiber length of 38 mm, and a circular fiber cross section (product name: Tetoron T403, manufactured by Toray Industries, Inc.). The official moisture regain was 0.4%.
PP fiber: a single fiber made of polypropylene having a fineness of 1.5 dtex, a fiber length of 38 mm, and a circular fiber cross section (trade name: PN, manufactured by Daiwabo Polytech Co., Ltd.). The official moisture regain was 0.0%.

Example 1
A parallel fiber web was produced by mixing 25% by weight of acrylic fiber, 50% by weight of rayon fiber, and 25% by weight of PET fiber using a parallel carding machine at a web target weight of about 40 g/ ^m2 .
The fiber web was placed on a 90 mesh plain weave support and transported at a speed of 4 m/min, and a water flow of 2.5 MPa was sprayed once from one surface side, followed by a water flow of 3.0 MPa from the other surface side, to perform a hydroentanglement treatment. The nozzle used in the hydroentanglement treatment was a nozzle with orifices of 0.1 mm diameter provided at 0.6 mm intervals, and the interval between the nozzle and the fiber web during treatment was 20 mm. The fiber web after the hydroentanglement treatment was then dried using a hot air penetration type heat treatment machine set at 80 ° C. to obtain a nonwoven fabric.

(Examples 2 to 6, Comparative Examples 1 to 4)
The types and proportions of fibers and the web target weight were as shown in Tables 1 and 2, and hydroentanglement and drying were carried out under the same conditions as those employed in Example 1 to obtain nonwoven fabrics.
The evaluation results of each of the examples and comparative examples are shown in Tables 1 to 4.

The physical properties in the table were measured by the following methods.
[Thickness, specific volume]
The thickness of the nonwoven fabric in the dry state was measured using a thickness gauge (product name THICKNESS GAUGE model CR-60A, manufactured by Daiei Scientific Instruments Co., Ltd.) under a load of 294 Pa or 1.96 kPa. The thickness of the nonwoven fabric in the wet state was measured using the same thickness gauge, with 100 parts by mass of the nonwoven fabric impregnated with 1,000 parts by mass of distilled water and a load of 294 Pa or 1.96 kPa being applied.
The specific volume was calculated from the basis weight of the nonwoven fabric and its thickness under a load of 1.96 kPa.

[Water retention rate]
The nonwoven fabric was cut into a size of 100 mm x 100 mm (machine direction x cross direction), the mass of the nonwoven fabric was measured, and the nonwoven fabric was then immersed in distilled water for 2 minutes. The nonwoven fabric soaked in distilled water was then hung with three corners pinched by clothespins, and the mass was measured after 10 minutes, and the water retention was calculated according to the following formula.
Water retention rate (%) = [(M2-M1)/M1] x 100
M1: Mass (g) of the nonwoven fabric before being impregnated with distilled water
M2: Mass (g) of the nonwoven fabric after it is soaked in distilled water and then hung for 10 minutes

[Suction height]
The wicking height was measured according to JIS L 1907:2010 7.1.2 Byreck method. A sample (MD direction x CD direction = 200 mm x 25 mm) was prepared with the water wicking direction in the MD direction, and the sample was set so that the water wicking direction coincided with the MD direction. After 300 seconds, the wicking height was measured. Measurements were taken for three samples, and the average value was taken as the wicking height (mm).

[Adhesion]
The adhesion force was measured using a static and dynamic friction measuring machine (Tribomaster TL201Ts, manufactured by Trinity Lab Co., Ltd.). A nonwoven fabric measuring 12 cm x 5 cm was prepared as a sample piece. The sample piece was prepared with the MD direction of the nonwoven fabric as the long side. An artificial skin (24 cm long x 12 cm wide, product name: BIO SKIN PLATE, manufactured and sold by: Viewlux Co., Ltd.) was placed on the measurement table of the measuring machine (table sliding type). In a state where 100 parts by mass of the sample piece was impregnated with 1000 parts by mass of distilled water, the end of the short side of the sample piece (this part is referred to as the "clip end") was clamped with the clip of the measuring machine to hold it horizontally. The measurement table was moved, and the sample piece was placed horizontally on the artificial skin so that only the area from the end opposite the clip end (this part is referred to as the "non-clip end") to the long side of the sample 8 cm overlapped with the artificial skin. The maximum resistance force (N) was read when the measurement table was moved parallel to the long side direction of the sample in the direction away from the clip end at a speed of 10 mm/sec along the long side direction of the sample piece. Three sample pieces were measured for each example, and the average value was calculated and used as the adhesion force (N). The initial adhesion force (N) was measured immediately after placing the sample piece on the artificial skin, and the adhesion force (N) was measured 20 minutes after placing the sample piece on the artificial skin.

[Dynamic friction coefficient, coefficient of variation]
The dynamic friction coefficient and the coefficient of variation were measured using a static and dynamic friction measuring instrument (Tribomaster TL201Ts, manufactured by Trinity Lab Co., Ltd.). A nonwoven fabric measuring 5 cm x 10 cm was prepared as a sample piece. The sample pieces were prepared with the MD direction of the nonwoven fabric as the long side and the CD direction as the long side. A tactile contactor (manufactured by Trinity Lab Co., Ltd.) was used as the contact terminal of the measuring instrument. In a state where 100 parts by mass of the sample piece was impregnated with 1000 parts by mass of distilled water, the sample piece was fixed to the measuring table of the measuring instrument (table sliding type), and the contact terminal was moved back and forth twice against the surface of the sample piece with a load of 30 gf, a speed of 10 mm/sec, and a distance of 30 mm. The value of the dynamic friction force in the second round trip was read, and the average value of the forward value and the return value was taken as the dynamic friction force (gf) of one sample piece.

The test piece with the long side in the MD direction was measured three times, and the test piece with the long side in the CD direction was measured three times, and the average value of the total six measurements was taken as the kinetic friction force Fk (gf) of each Example and Comparative Example. The kinetic friction coefficient μk was calculated from the kinetic friction force Fk (gf) and the load (30 gf). In addition, the coefficient of variation CV of the kinetic friction coefficient was calculated according to the following formula from the standard deviation σ of the kinetic friction coefficient obtained during the measurement and the average value μk of the kinetic friction coefficient described above.
Coefficient of variation of dynamic friction coefficient CV = σ/μk

[Bending resistance]
The bending resistance of the nonwoven fabric was measured in accordance with JIS L 1096:2010 8.21.5 E method (handle-o-meter method). Specifically, the bending resistance was measured by the following procedure.
A sample piece measuring 20 cm x 20 cm in MD x CD is placed on the sample stage so that the measurement direction of the sample piece is perpendicular to the slot (gap width 10 mm).
Next, the blade of the penetrator, adjusted so that it is 8 mm below the surface of the sample stage, is lowered, and the sample piece is pressed into it. When the blade is 6.7 cm (1/3 of the width of the sample piece) from one side, the resistance to the pressing is read at different points on both sides (total of four points) in the vertical and horizontal directions. The maximum value (mN) indicated by the microammeter is read as the resistance value. The maximum values of the four sides are calculated and the average of the three measurements is calculated, and this is the bending resistance (mN) of the sample.

[Breaking strength, breaking elongation, stress at 10% and 20% elongation]
According to JIS L 1096:2010 8.14.1 A method (strip method), a constant-speed tension type tensile tester was used to perform a tensile test under the conditions of a sample width of 50 mm, a grip distance of 10 cm, and a tensile speed of 30±2 cm/min, and the load value at break (breaking strength), breaking elongation, stress at 10% elongation, and stress at 20% elongation were measured. The tensile test was performed in the longitudinal direction (MD direction) and transverse direction (CD direction) of the nonwoven fabric as the tensile direction. The evaluation results are shown as the average of the values measured for three samples.
The breaking strength in wet state was measured in a state where 100 parts by mass of the nonwoven fabric was impregnated with 250 parts by mass of distilled water.

All of Examples 1 to 6 contained acrylic fiber as chemical fiber A and had a specific volume of 12 cm ³ /g or more, and therefore showed higher initial adhesion than the comparative examples. Examples 1 to 5 also showed higher adhesion after 20 minutes than the comparative examples. Although Example 6 had a smaller adhesion after 20 minutes than Comparative Example 1, it was still fully usable. The reason why Example 6 had a slightly smaller adhesion after 20 minutes is thought to be because it contained a large amount of acrylic fiber and the impregnated distilled water evaporated relatively quickly. Acrylic fiber has a relatively lower official moisture regain than hydrophilic fiber, and has wrinkled recesses on the fiber side due to fine recesses formed in the fiber cross section, which is thought to promote evaporation of liquid. Comparative Example 1 had the same type and ratio of fibers as Examples 1 and 2, but had a large basis weight and a small specific volume, and therefore showed a small initial adhesion. Comparative Examples 2 to 4 did not contain acrylic fiber, and therefore could not achieve a specific volume of 12 cm ³ /g or more when the basis weight was about 50 g/m ² , and also showed a small initial adhesion.

All of Examples 1 to 6 had higher wicking heights and demonstrated excellent liquid absorption properties compared to Comparative Examples 2 and 4, which did not contain acrylic fibers. The wicking height of Example 5 was lower than the other Examples. This is thought to be because the hydrophilic fiber content was low and the acrylic fiber content was not as high as in Example 6, making it relatively difficult for liquid to move.

The dynamic friction coefficient μk is an index of the feeling of adhesion, and the higher this is, the easier it is for the nonwoven fabric to adhere to the skin. When comparing nonwoven fabrics with the same target size (Examples 2 to 4), the dynamic friction coefficient μk tended to be higher as the proportion of acrylic fibers increased. This is thought to be because acrylic fibers contain many fine protrusions, which results in high surface friction and makes them less likely to slip.

The coefficient of variation is an index of the smoothness of the nonwoven fabric surface; the higher the coefficient, the rougher the nonwoven fabric feels and the worse it feels on the skin. Although there was no significant difference in the coefficient of variation between the Examples and Comparative Examples, the coefficient of variation in Comparative Example 1 was the largest. This is thought to be because the basis weight was the largest. Although the coefficient of variation can be improved by reducing the specific volume, it is difficult to obtain a practical nonwoven fabric for liquid-impregnated skin application sheets that exhibits good adhesion when the specific volume is small.

Comparative Example 1 had a large basis weight, so the bending resistance was high and flexibility was poor. As a result, the ability to conform to curved surfaces was poor.

In all of Examples 1 to 6, the stress at 10% elongation in the MD direction when dry and wet, and the stress at 20% elongation in the MD direction when dry and wet, were smaller than those of Comparative Examples 1 and 3, which contained acrylic fibers. This is thought to be because the specific volume of the nonwoven fabrics of Examples 1 to 6 was larger than that of the nonwoven fabrics of Comparative Examples 1 and 3. Since the nonwoven fabrics of Examples 1 to 6 have a moderately low stress at 10% elongation and 20% elongation in the MD direction, when a sheet using this as a base material is applied to the skin, the sheet can be moderately elongated in the vertical direction and cover the skin by following the curved surface and unevenness of the skin. In addition, although the specific volume of all of Examples 1 to 6 is large, the breaking strength was not significantly lower than that of Comparative Examples 1 to 4. This is thought to be because the fine unevenness on the surface of the acrylic fibers contributes to entanglement and suppresses the decrease in strength.

The nonwoven fabric of this embodiment includes the following aspects.
(Aspect 1)
The fabric has an official moisture regain of 1.0% to 7.0% and contains 20% to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% to 80% by mass of hydrophilic fibers,
The specific volume when dried is 12.0 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 .
Nonwoven fabric for liquid-impregnated skin covering sheets.
(Aspect 2)
The fabric has an official moisture regain of 1.0% to 7.0% and contains 20% to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% to 80% by mass of hydrophilic fibers,
The specific volume when wet is 8.8 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 .
Nonwoven fabric for liquid-impregnated skin covering sheets.
(Aspect 3)
3. The nonwoven fabric for a liquid-impregnated skin-covering sheet according to claim 1 or 2, wherein the chemical fiber is an acrylic fiber.
(Aspect 4)
The nonwoven fabric for a liquid-impregnated skin-covering sheet according to any one of Aspects 1 to 3, which has a single-layer structure.
(Aspect 5)
The nonwoven fabric for a liquid-impregnated skin-applying sheet according to any one of Aspects 1 to 4, further comprising a polyester single fiber.
(Aspect 6)
6. The nonwoven fabric for a liquid-impregnated skin-covering sheet according to any one of Aspects 1 to 5, wherein the fibers are not bonded to each other.
(Aspect 7)
The liquid-impregnated nonwoven fabric for skin-covering sheets according to any one of Aspects 1 to 6, which has a wicking height of 35 mm or more when dry.
(Aspect 8)
A liquid-impregnated skin application sheet obtained by impregnating the nonwoven fabric of any one of Aspects 1 to 7 with a liquid.
(Aspect 9)
A face mask obtained by impregnating the nonwoven fabric of any one of Aspects 1 to 7 with a liquid.

The nonwoven fabric of the present disclosure has a relatively large specific volume and adheres well to the skin when impregnated with liquid, making it useful as a base material for liquid-impregnated skin-covering sheets such as face masks.

Claims (8)

The fabric has an official moisture regain of 1.0% to 7.0% and contains 20% to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% to 80% by mass of hydrophilic fibers,
The specific volume when dried is 12.0 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 ,
The fibers are not bonded together,
Further, the material contains chemical fibers having an official moisture regain of less than 1.0% in an amount of 15% by mass or more and 35% by mass or less.
Nonwoven fabric for liquid-impregnated skin covering sheets. The fabric has an official moisture regain of 1.0% to 7.0% and contains 20% to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% to 80% by mass of hydrophilic fibers,
The specific volume when wet is 8.8 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 ,
The fibers are not bonded together,
Further, the material contains chemical fibers having an official moisture regain of less than 1.0% in an amount of 15% by mass or more and 35% by mass or less.
Nonwoven fabric for liquid-impregnated skin covering sheets. The fabric has an official moisture regain of 1.0% to 7.0% and contains 20% to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% to 80% by mass of hydrophilic fibers,
The specific volume when dried is 12.0 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 ,
The fibers are not bonded together,
The chemical fiber is an acrylic fiber,
Further, the material contains chemical fibers having an official moisture regain of less than 1.0% in an amount of 15% by mass or more and 35% by mass or less.
Nonwoven fabric for liquid-impregnated skin covering sheets. The fabric has an official moisture regain of 1.0% to 7.0% and contains 20% to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% to 80% by mass of hydrophilic fibers,
The specific volume when wet is 8.8 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 ,
The fibers are not bonded together,
The chemical fiber is an acrylic fiber,
Further, the material contains chemical fibers having an official moisture regain of less than 1.0% in an amount of 15% by mass or more and 35% by mass or less.
Nonwoven fabric for liquid-impregnated skin covering sheets. The fabric has an official moisture regain of 1.0% to 7.0% and contains 20% to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% to 80% by mass of hydrophilic fibers,
The specific volume when dried is 12.0 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 ,
The fibers are not bonded together,
It has a single layer structure,
Further, the material contains chemical fibers having an official moisture regain of less than 1.0% in an amount of 15% by mass or more and 35% by mass or less.
Nonwoven fabric for liquid-impregnated skin covering sheets. The fabric has an official moisture regain of 1.0% to 7.0% and contains 20% to 80% by mass of chemical fibers having at least one recess or constriction in a fiber cross section, and 20% to 80% by mass of hydrophilic fibers,
The specific volume when wet is 8.8 ^cm3 /g or more,
The basis weight is 20 to 55 g/ ^m2 ,
The fibers are not bonded together,
It has a single layer structure,
Further, the material contains chemical fibers having an official moisture regain of less than 1.0% in an amount of 15% by mass or more and 35% by mass or less.
Nonwoven fabric for liquid-impregnated skin covering sheets. A liquid-impregnated skin covering sheet obtained by impregnating the nonwoven fabric according to any one of claims 1 to 6 with a liquid. A face mask obtained by impregnating the nonwoven fabric according to any one of claims 1 to 6 with a liquid.

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