TWI730105B - Long fiber non-woven fabric - Google Patents

Abstract

The long-fiber non-woven fabric of the present invention contains a liquid film cracking agent.

Description

Long fiber non-woven fabric

The present invention relates to a long-fiber non-woven fabric.

As for the front sheet of absorbent articles, hot-air non-woven fabrics using short fibers as raw materials have been mainly used in the past. In response to this, in recent years, from the viewpoint of manufacturing cost and productivity, research has been conducted to use a nonwoven fabric using long fibers such as spunbonded nonwoven fabric as a raw material (hereinafter referred to as a long fiber nonwoven fabric) as a front sheet. However, compared with non-woven fabrics made of short fibers, long-fiber non-woven fabrics have problems such as a shorter distance between fibers, a thinner thickness, and higher rigidity in the thermal fusion part where the long fibers are bundled. Therefore, the conventional long-fiber non-woven fabrics are not yet sufficiently satisfactory in terms of liquid residue or liquid return suppression, texture, etc. required by the front sheet. There are several proposals for this.

For example, Patent Document 1 describes that the long-fiber nonwoven fabric described above includes fibers in which a part of the long fibers bundled by a thermal fusion portion is broken and raised. Regarding this erected fiber, it is described that the hydrophilicity of the fiber is lower than that of the long fiber that is bundled without being broken. In this way, it is desired to impart cushioning properties to the thinner spunbonded non-woven fabrics to improve liquid permeability and prevention of liquid return.

As a different technique from this, Patent Document 2 describes an absorbent article in which a blood modifier is contained in the front sheet in order to improve the dry feeling. The blood modifier intends to reduce the viscosity and surface tension of blood, stabilize blood cells and not easily form a string structure, so that the absorber can easily absorb menstrual blood. In addition, Patent Document 3 describes that from the viewpoint of making the flow of body fluids of the surface sheet difficult to occur or re-bleeding, the back side of the surface sheet is given a higher degree of hydrophilicity than the surface side.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-139359

[Patent Document 2] Japanese Patent Laid-Open No. 2013-63245

[Patent Document 3] Japanese Patent Laid-Open No. 2005-87659

The invention provides a long-fiber non-woven fabric which contains a liquid film cracking agent.

In addition, the present invention provides a long-fiber non-woven fabric containing a compound (C1) having a water solubility of 0 g or more and 0.025 g or less, and a spread coefficient of 15 mN/m for a liquid with a surface tension of 50 mN/m The above.

In addition, the present invention provides a long-fiber non-woven fabric containing a compound (C2) which has a water solubility of 0 g or more and 0.025 g or less, and a spread coefficient for a liquid with a surface tension of 50 mN/m greater than 0 mN/m , For liquids with a surface tension of 50mN/m, the interfacial tension is below 20mN/m.

The above-mentioned and other features and advantages of the present invention are made more clear from the following description with appropriate reference to the accompanying drawings.

1: Long fiber

2: Heat fusion part

3: Fiber assembly layer

4: erect fiber

5: Side 1

6: Side 2

7: Liquid film

8: Liquid film cracking agent

10, 20, 30: Long fiber non-woven fabric

11: Fiber on the first side

12: Fiber on the second side

31: The first fiber layer

32: 2nd fiber layer

41: Base end

42: free end

74, 75: Concave and convex rollers

76: Conveying roller

77: Raising roller

79: Protruding part

104: Test sample

105: crease

106a: fiber

107: Hole of Backing Paper

108: imaginary line

200: Raw material long fiber non-woven fabric

Figure 1 is a schematic diagram showing a preferred embodiment of the long fiber nonwoven fabric of the present invention, (A) is a diagram showing a single layer of long fiber nonwoven fabric, (B) is a diagram showing another single layer of long fiber nonwoven fabric, ( C) is a diagram showing multiple layers of long-fiber non-woven fabric.

Fig. 2 is a schematic diagram showing the liquid film formed in the gaps between the fibers of the long-fiber nonwoven fabric.

Figure 3 (A1)~(A4) is a schematic illustration showing the state of the liquid film cracking agent causing the liquid film to be cracked from the side, and (B1)~(B4) is a schematic illustration of the liquid film cracking agent making the liquid from the top Cracked membrane Illustrative diagram of the state.

Fig. 4 is an explanatory diagram showing the raising process steps, (A) is a schematic diagram showing the partial stretching process steps, (B) is a partially enlarged representation of the meshing state of the concave and convex rollers in one of the partial stretching process steps in (A) Cross-sectional view, (C) is a schematic diagram showing the fracture processing steps.

Fig. 5 is an explanatory diagram schematically showing the method of measuring the number of fluffed fibers, (A) is a diagram showing the state after the long-fiber non-woven fabric is raised and folded, and (B) is shown in the length of (A) The figure showing the state where the fiber nonwoven fabric is overlapped with the black backing paper with openings, (C) is an explanatory diagram showing the method of expanding the opening of the black thread backing paper of (B) and measuring the fluffed fibers from the opening.

The present invention relates to a long-fiber non-woven fabric with a shorter distance between fibers than a non-woven fabric using short fibers as a raw material, which can reduce the liquid film formed between the fibers, inhibit liquid residue and liquid return through the liquid residue, and achieve higher Long-fiber non-woven fabric with a standard dry feeling.

In the long-fiber nonwoven fabric, even if there are fibers with free ends described in Patent Document 1, the spread of the fiber-to-fiber distance is limited to a part. For example, in the fiber assembly part or the periphery of the heat fusion part where the long fibers are not broken but are bundled by the heat fusion part, the distance between the fibers is short. In the area where the distance between the fibers is short, even if there is a space through which excretion fluid (such as urine or menstrual blood; also referred to as liquid) can pass, it is also due to the capillary force of the meniscus between the fibers or the surface activity produced by plasma proteins , And high blood surface viscosity, so it will form a stable liquid film between the fibers and easy to retain liquid. The liquid film becomes a stable film between the shorter fibers. Therefore, once it is produced, it is difficult to eliminate even if the hydrophilicity gradient or the blood modifier that stabilizes the blood cells is used. Even with the use of previous blood modifiers, etc., there is still room for improvement in the dry feeling felt by the wearer. That is, there is still room for improvement in the suppression of liquid residue or liquid return from the absorber through the liquid residue portion.

In addition, the liquid to be absorbed is not limited to blood. Urine also has surface activity derived from phospholipids, but a liquid film is formed in the same manner as described above. Liquid residue and liquid return through the liquid residue are not sufficiently suppressed, and a dry feeling is still maintained. There is room for improvement.

As described above, a technique is required to remove the liquid film formed in the non-woven fabric in the narrow portion between the fibers and make it absorbed into the absorbent body. However, it is difficult to remove the liquid film due to the high stability of the liquid film. In addition, it is also considered to coat water-soluble surfactants to reduce the surface tension of the liquid and remove the liquid film. However, if such a surfactant is to be used in an absorbent article to achieve liquid film removal, there is a risk that the liquid will also pass through the liquid-proof backsheet.

The long-fiber non-woven fabric of the present invention can reduce the liquid film formed between the fibers, inhibit liquid residue and liquid return through the liquid residue, and achieve a higher level of dryness.

The long-fiber non-woven fabric of the present invention contains a liquid film cracking agent. In addition, the long-fiber nonwoven fabric of the present invention preferably includes heat-fusible fibers, and has a first surface and a second surface located on the opposite side of the first surface, and the hydrophilicity of the fibers on the first surface is lower than that of the second surface. The hydrophilicity of the fiber on the side.

The so-called liquid film cracking agent refers to the liquid film that is formed between the fibers of the non-woven fabric or the surface of the fiber by contacting the liquid, such as menstrual blood and other high-viscosity liquids or urine and other excretion fluids, to crack the liquid film formed between the fibers of the non-woven fabric or on the surface of the fibers. The effect of the formed liquid film cracking and the effect of inhibiting the formation of the liquid film. The former can be described as the main role, and the latter can be described as the subordinate role. The cracking of the liquid film is achieved by the effect of the liquid film cracking agent pushing a part of the liquid film layer to destabilize it.

The action of the liquid film cracking agent prevents the liquid from remaining in the narrow area between the fibers and makes it easier to pass through, and complements the absorption of the liquid using the above-mentioned hydrophilicity gradient to improve the long-fiber non-woven fabric of the present invention. Its liquid permeability helps reduce liquid residue and liquid return. Thereby, even if the fibers constituting the long-fiber nonwoven fabric are thinned and the distance between the fibers is narrowed, the softness of the skin touch and the suppression of the liquid residue are also achieved. The long-fiber non-woven fabric of this invention can be used, for example Used as the front sheet of absorbent articles such as menstrual sanitary napkins, baby diapers, and adult diapers.

(The property of making the liquid film disappear)

The liquid film cracking agent used in the present invention has the property of making the liquid film disappear. With this property, when the liquid film cracking agent is applied to the test liquid or artificial urine mainly composed of plasma components, it can be expressed The effect of disappearing liquid film. The artificial urinary system will have 1.940% by mass of urea, 0.795% by mass of sodium chloride, 0.110% by mass of magnesium sulfate, 0.062% by mass of calcium chloride, 0.197% by mass of potassium sulfate, 0.010% by mass of red No. 2 (dye), and water (approximately 96.88% by mass). Mass%) and polyoxyethylene lauryl ether (approximately 0.07 mass%) and the surface tension of the mixture is adjusted to 53±1mN/m (23°C). The so-called liquid film disappearing effect here includes the following two effects, namely, against the structure body that entrains air due to the liquid film formed by the test liquid or artificial urine, suppressing the formation of the liquid film of the structure body, and making the formed structure body Disappearing, an agent that exhibits at least one effect can be said to have the property of exhibiting the disappearing effect of the liquid film.

The above-mentioned test liquid is a liquid component extracted from defibrinated horse blood (manufactured by NIPPON BIOTEST Co., Ltd.). Specifically, if 100 mL of defibrinated horse blood is allowed to stand for 1 hour under the conditions of a temperature of 22° C. and a humidity of 65%, the defibrinated horse blood is separated into an upper layer and a lower layer. At this time, the upper layer is the above-mentioned test liquid. The upper layer mainly contains plasma components, and the lower layer mainly contains blood cell components. When removing only the upper layer from the defibrinated horse blood separated into the upper layer and the lower layer, for example, a pipette (manufactured by Kensakizai Co., Ltd.) can be used.

Regarding whether a certain agent has the above-mentioned "property to make the liquid film disappear", it is set to a state where it is easy to produce a structure that entrains air due to the liquid film formed by the above-mentioned test liquid or artificial urine applied with the agent, according to the situation When determining the amount of the structure, that is, the amount of liquid film. That is, the test solution or artificial urine was adjusted to a temperature of 25°C, and then 10 g was added to a spiral tube (No. 5 manufactured by Maruemu Co., Ltd., a tube diameter of 27 mm, and a total length of 55 mm) to obtain a standard sample. In addition, as a measurement sample, one obtained by adding 0.01 g of an agent to be measured that has been adjusted to 25°C in advance was added to the same thing as the standard sample. The standard sample and the measurement sample were vigorously oscillated twice in the upper and lower directions of the spiral tube, respectively, and then quickly placed on a horizontal surface. By the oscillation of the sample, a liquid layer (lower layer) without the above-mentioned structure and a structure layer (upper layer) containing a large amount of the structure formed on the liquid layer are formed inside the spiral tube after the oscillation. Immediately after the end of the shaking 10 seconds, the height of the structure layer (the height from the liquid level of the liquid layer to the upper surface of the structure layer) of the two samples was measured. Then, when the height of the structure layer of the measurement sample is 90% or less relative to the height of the structure layer of the standard sample, the agent to be measured is regarded as having a liquid film cracking effect.

The liquid film cracking agent used in the present invention is a single compound that meets the above properties or a mixture of multiple combinations of a single compound that meets the above properties, or a combination of multiple compounds that meets the above properties (which can make the liquid film Cracking) of the agent. That is, the term "liquid film cracking agent" refers to an agent limited to those having a liquid film cracking effect based on the above definition. Therefore, when the compound used in the absorbent article contains the third component that does not meet the above definition, it is distinguished from the liquid film cracking agent.

Furthermore, with regard to the liquid film cracking agent and the third component, the so-called "single compound" includes a concept including compounds having the same composition formula but different molecular weights depending on the number of repeating units.

As the liquid film cracking agent, it can be appropriately selected and used from those described in paragraphs [0007] to [0186] of the specification of International Publication No. 2016/098796.

In the present invention, the term "long-fiber non-woven fabric" refers to a non-woven fabric provided with a fiber assembly layer in which long fibers are intermittently fixed by a thermal fusion part. The so-called "long fiber" means a fiber with a fiber length of 30 mm or more. Especially if it is the so-called continuous fiber length of 150mm or more Long fibers are better for obtaining long fiber non-woven fabrics with higher breaking strength. Examples of such long-fiber nonwoven fabrics include spunbonded nonwoven fabrics, multiple layers of nonwoven fabrics including a spunbonded layer and a meltblown layer, and hot rolled nonwoven fabrics using a carding method. Examples of non-woven fabrics containing multiple layers include: spunbond-spunbond laminated nonwoven fabric, spunbonded-spunbonded-spunbonded laminated nonwoven fabric, spunbonded-meltblown-spunbonded laminated nonwoven fabric, spunbonded-spunbonded-meltblown- Spunbond laminated non-woven fabrics, etc. Moreover, in the case of a single layer, a long-fiber non-woven fabric having fibers (upright fibers) standing upright in a state where one end of the long fibers is not fixed to the fiber assembly layer on one side is exemplified. Furthermore, the upper limit of the fiber length in the aforementioned "long fiber" is not particularly limited.

In addition, the above-mentioned so-called fibers on the first surface side and fibers on the second surface side refer to fibers on the outermost surface of the laminated long-fiber nonwoven fabric even in the case of multiple layers.

Fig. 1(A)~(C) show specific examples of the layer structure of the long-fiber nonwoven fabric of the present invention. However, the long-fiber nonwoven fabric of the present invention is not limited to them, and various forms can be adopted. Furthermore, the first surface 5 shown in Fig. 1(A)~(C) becomes the liquid-receiving surface side (that is, the skin contact surface side) when the long-fiber nonwoven fabric is used as the front sheet of the absorbent article Surface, the second surface 6 is the surface on the absorber side (that is, the non-skin contact surface side).

Fig. 1(A) shows a single-layer long-fiber nonwoven fabric 10. The long-fiber nonwoven fabric 10 includes a fiber assembly layer 3 in which the long fibers 1 are intermittently fixed by the thermal fusion part 2. The long-fiber nonwoven fabric 10 has a hydrophilicity degree of the fibers 11 on the first surface 5 side which is the liquid receiving surface lower than the hydrophilicity degree of the fibers 12 on the second surface 6 side which is the opposite surface side, and has a hydrophilicity gradient. Here, the fiber on the first surface 5 side refers to the fiber on the surface of the fiber assembly layer 3 on the first surface 5 side. The fibers on the second surface 6 side refer to fibers on the surface of the fiber assembly layer 3 on the second surface 6 side.

Fig. 1(B) shows another single-layer long-fiber nonwoven fabric 20. Examples of the long-fiber non-woven fabric 20 include: the length of the erect fiber 4 having one end side that is not fixed to the fiber assembly layer 3 on the first surface 5 side Fiber non-woven fabric 20. The upright fiber 4 has a base portion 41 fixed to the heat fusion part 2 of the fiber assembly part 3 and a free end 42 that is not fixed to the heat fusion part 2 of the fiber assembly layer 3. The free end 42 can be erected from the fiber assembly layer 3 to the upper side of the first surface 5 side. In this case, the fiber on the first surface 5 side is the erect fiber 4 on the surface of the fiber assembly layer 3 on the first surface 5 side. The fiber on the second surface 6 side is the fiber 12 on the surface of the fiber assembly layer 3 on the second surface 6 side. The hydrophilicity of the erect fibers 4 is lower than the hydrophilicity of the fibers on the second surface 6 side.

Fig. 1(C) shows a long-fiber nonwoven fabric 30 of multiple layers. The long-fiber non-woven fabric 30 may be a long-fiber non-woven fabric 30 formed by laminating a plurality of fiber assembly layers bundled by the heat fusion part 2. The long-fiber nonwoven fabric 30 has a first fiber assembly layer 31 on the first surface 5 side, and a second fiber assembly layer 32 on the second surface 6 side. In addition, the plural layers are not limited to two layers as shown in FIG. 1(C), but may be three or more layers. The plurality of fiber assembly layers are preferably integrated in the state of being laminated, and for example, it is preferably joined by hot embossing, hot melt adhesive, or the like. In the case of using a hot melt adhesive, from the viewpoint of liquid permeability, it is preferable to bond between layers by an intermittent coating method such as spiral coating. Or, it is more preferable to use a hot melt adhesive to join only the periphery in the plane direction, and take more non-joining areas to leave the interface between the layers. In this case, the fiber on the first surface 5 side is the fiber 11 on the surface of the first fiber layer 31 on the first surface 5 side. The fiber on the second surface 6 side is the fiber 12 on the surface of the second fiber layer 32 on the second surface 6 side. Furthermore, in the multi-layer long-fiber nonwoven fabric 30 shown in FIG. 1(C), the first fiber assembly layer 31 on the side of the first surface 5 may also be the one having the erect fibers 4 shown in FIG. 1(B). Fiber assembly layer 3 (not shown).

Regarding the above-mentioned hydrophilicity of the long-fiber nonwoven fabric of the present invention, it is preferable that there is a gradient of hydrophilicity from the first surface side to the second surface side.

The above-mentioned "hydrophilicity gradient", unless otherwise specified, means the following state: in the thickness direction of the long-fiber non-woven fabric, the liquid-receiving surface (for example, the front sheet of a diaper) The side of the skin contact surface in the case of the material, and the opposite surface (for example, the non-skin contact surface in the above-mentioned front sheet) side has a higher degree of hydrophilicity. The "gradient" broadly includes various aspects in which there is a difference in the degree of hydrophilicity between the liquid receiving surface side and the opposite surface side. It may be a state that gradually increases or a state that gradually increases. kind. When it is called staged, it may be two stages or three or more stages. The above-mentioned hydrophilicity gradient only needs to be a gradient from the first surface side (liquid-receiving surface side) to the second surface side along the permeation direction of the liquid, and it is not strictly limited to the first surface (liquid-receiving surface) perpendicular to the non-woven fabric. The gradient in the direction of the surface).

For example, when a plurality of layers are included, each layer may have a difference in hydrophilicity and gradually increase. In addition, the height may be gradually or stepwise in each layer, and the length of the long-fiber nonwoven fabric as a whole may be gradually or stepwisely increased from the liquid-receiving surface side to the opposite surface side. Alternatively, the hydrophilicity of only the layer on the liquid-receiving surface side (the first surface 5 side in FIG. 1(C)) is lower than the two-step hydrophilicity gradient of the other layers. In addition, the hydrophilicity of only the fiber on the outermost surface of the layer on the liquid-receiving surface side is lower than that of other fibers in the same layer and the two-step hydrophilicity gradient of the fibers of other layers. On the other hand, when a single layer is included, the degree of hydrophilicity in the thickness direction within the layer may gradually or stepwise increase. Or, it can also be a two-stage hydrophilicity gradient in which only the surface fiber on the liquid receiving surface side (the first surface 5 side in Figure 1 (A) and (B)) is lower than the hydrophilicity of other fibers in the layer The state.

Especially in the long-fiber nonwoven fabric 20 of FIG. 1(B), from the viewpoint of improving the liquid absorption along the erect fibers 4, it is preferable that the erect fibers 4 have a lower hydrophilicity than the fibers of the fiber assembly layer 3. The degree of hydrophilicity has at least two stages of hydrophilicity gradient.

In the long-fiber non-woven fabric of the present invention, the above-mentioned liquid film cracking agent is applied to the constituent fibers of at least a part of the long-fiber non-woven fabric. The so-called at least a part for coating is preferably the part that catches the most liquid. For example, the long-fiber non-woven fabric of the present invention is used as In the case of the front sheet of menstrual sanitary napkins and other absorbent articles, the area corresponding to the wearer's excretory part directly catches the excretion fluid such as menstrual blood.

Furthermore, regarding the thickness direction of the long-fiber nonwoven fabric of the present invention, it is preferable that the liquid film cracking agent be contained at least on the liquid receiving surface side (side close to the skin in the absorbent article) for receiving liquid. Regarding the front sheet of the above example, it is preferable that at least the skin contact surface side which is in contact with the wearer's skin contains a liquid film cracking agent. Furthermore, from the viewpoint of liquid permeability, it is more preferable to exist in the thickness direction as much as possible, and especially when a plurality of layers are included, it is more preferable to exist in as many layers as possible.

If there is a liquid film cracking agent at least on the side of the receiving surface, the liquid film cracking agent will be dispersed in a part of the liquid after passing the liquid, and as the liquid passes through, it may adhere to the fibers that are not coated with the liquid film cracking agent. Liquid film cracking agent. As a result, the effect of the liquid film cracking agent will also be exerted during the second and subsequent passes.

In the present invention, the so-called long-fiber non-woven fabric containing or containing a liquid film cracking agent mainly refers to adhere to the surface of the fiber. However, as long as the liquid film cracking agent remains on the surface of the fiber, it may be what is contained in the fiber, or may be what is present in the fiber by internal addition. As a method for attaching the liquid film cracking agent to the fiber surface, various methods commonly used can be adopted without particular limitation. For example, flexographic printing, inkjet printing, gravure printing, screen printing, spraying, brushing, etc. may be mentioned. These treatments can be carried out after the fibers are made into a fiber web by various methods, and thereafter, the fiber web can be made into a non-woven fabric or after being incorporated into an absorbent article. The fiber with the liquid film cracking agent attached to the surface is dried at a temperature sufficiently lower than the melting point of the fiber resin (for example, 120°C or less) by using a hot-air blower dryer, for example. In addition, when the liquid film cracking agent is attached to the fiber using the above-mentioned attachment method, the liquid film cracking agent can be used without diluting the liquid film cracking agent, and a liquid film containing liquid film formed by dissolving the liquid film cracking agent in a solvent can also be used if necessary. Cracking agent solution, or Emulsion and dispersion of liquid film cracking agent.

Regarding the liquid film cracking agent of the present invention, in order for the non-woven fabric to have the following liquid film cracking effect, the liquid film cracking agent must be present in a liquid form when it comes into contact with body fluids. In this respect, the melting point of the liquid film cracking agent of the present invention is preferably 40°C or less, more preferably 35°C or less. Furthermore, the melting point of the liquid film cracking agent of the present invention is preferably -220°C or higher, more preferably -180°C or higher.

Here, the above-mentioned effect of the liquid film cracking agent in the long-fiber nonwoven fabric of the present invention will be specifically described with reference to FIGS. 2 and 3.

As shown in FIG. 2, in the narrow area between the fibers, the liquid film 7 is easily expanded by the more viscous liquid such as menstrual blood or the excretion liquid such as urine. In response to this, the liquid film cracking agent destabilizes the liquid film and breaks the film in the following manner, thereby suppressing the formation of the liquid film and promoting drainage from the non-woven fabric. First, as shown in FIGS. 3 (A1) and (B1), the liquid film cracking agent 8 of the long-fiber nonwoven fiber 1 moves on the surface of the liquid film 7 while maintaining the interface with the liquid film 7. Then, the liquid film cracking agent 8 is as shown in Figure 3 (A2) and (B2), pushing a part of the liquid film 7 and infiltrating in the thickness direction, as shown in Figure 3 (A3) and (B3), Slowly make the liquid film 7 uneven and change it to a thinner film. As a result, the liquid film 7 cracked due to the occurrence of voids in a cracking manner as shown in Figs. 3 (A4) and (B4). The cracked menstrual blood and other liquids become liquid droplets, and it becomes easier to pass between the fibers of the long-fiber non-woven fabric to reduce liquid residue. In addition, the effect of the above-mentioned liquid film cracking agent on the liquid film is not limited to the case of the liquid film between the fibers, and it also acts on the liquid film wound on the surface of the fiber in the same way. That is, the liquid film cracking agent can move on the liquid film wound on the surface of the fiber, thereby pushing away a part of the liquid film to crack the liquid film. In addition, for the liquid film wound on the fiber surface, even if the liquid film cracking agent does not move on the position where it adheres to the fiber, it will crack the liquid film due to its hydrophobic effect, thereby suppressing the formation of the liquid film.

As mentioned above, the liquid film cracking agent does not reduce the surface tension of the liquid film, etc. The quality of the liquid film itself is pushed open between the fibers or on the surface of the fibers to crack it, and inhibit the formation of the liquid film, thereby promoting the drainage of the liquid from the long-fiber non-woven fabric. Thereby, the liquid residue of the long-fiber non-woven fabric can be reduced. In addition, if such a long-fiber nonwoven fabric is incorporated into an absorbent article as a front sheet, the liquid retention between the fibers is suppressed, and the liquid permeation path to the absorbent body is ensured. Thereby, the permeability of the liquid is improved, the flow of the liquid on the surface of the sheet is suppressed, and the absorption speed of the liquid is increased. In particular, it can increase the absorption speed of fluids that are easy to remain between the fibers, such as menstrual blood with high viscosity. In addition, contamination such as red color in the front sheet is not easily noticeable, and it becomes an absorbent article that can reliably feel the relief of absorption and has high reliability.

In the long-fiber nonwoven fabric of the present invention, as described above, the liquid film cracking agent acts in the form of a driving force that breaks the fine and stable liquid film generated between the narrow fibers to prevent it from breaking. stable. At the same time, the above-mentioned hydrophilicity gradient acts in the form of a driving force that will cause the liquid film to crack and unstable liquid from the fiber layer with lower hydrophilicity along the unidirectional direction before stabilizing the fiber surface again. Pump to a fiber layer with higher hydrophilicity. In addition, even if the liquid returns slightly due to pressure or the like, the liquid film cracking agent inhibits the formation of a stable liquid film, and is sucked back to the fiber layer with higher hydrophilicity.

As mentioned above, the driving forces of the above-mentioned liquid film cracking agent and the hydrophilicity gradient are synergistic, which hinders the stabilization of the liquid between the fibers, and improves the liquid permeability of the liquid in the long-fiber non-woven fabric in the thickness direction to suppress liquid residue . Thereby, it has the liquid permeability which can also quickly respond to the new receiving liquid, and it is possible to reduce the liquid residue or the liquid return through the liquid residue.

In addition, if a liquid film cracking agent is also present in the thermal fusion part 2 that bundles the long fibers, the liquid film on the film-like fiber surface of the thermal fusion part can also be cracked, and the degree of hydrophilicity is ensured by the gradient. Let the liquid fall in the thickness direction from between the fibers. As a result, for long-fiber non-woven fabrics, even the liquid residue in the unique thermal fusion part or the liquid return caused by the liquid residue can be reduced.

Furthermore, in the long-fiber nonwoven fabric 20 shown in FIG. 1(B), it was confirmed that the standing fibers 4 containing a liquid film cracking agent and having a low hydrophilicity function as follows when the liquid is supplied.

That is, when the liquid is supplied to the side of the first surface 5 where the standing fibers 4 are present, the standing fibers 4 having a lower hydrophilicity than the fiber assembly layer 3 rise up on the free end 42 side, that is, floating. Furthermore, the erect fiber 4 is in a certain degree (the degree of floating from the fiber assembly layer 3) in an erect state when it is not in contact with liquid. The above-mentioned so-called "upright fiber 4 erected by contact with liquid" means that the degree of erection becomes greater than the state before contact with liquid, that is, the angle formed by the erect fiber 4 and the fiber assembly layer 3 changes. Big. The erect fiber 4 is in a state where the erection degree becomes larger during the contact with the liquid. In this state, on the surface of the upright fiber 4, the liquid film is eliminated by the above action of the liquid film cracking agent 3, and the liquid moves along the upright fiber and is attracted to the fiber assembly layer 3 with relatively high hydrophilicity. Inside. In this way, liquid residue is reduced. Moreover, after absorbing the liquid, the upright fibers 4 with low hydrophilicity return to the original upright state with a small degree of erection, and cover the first surface 5 side of the fiber assembly 3 to a certain extent from above. Thereby, the standing fiber 4 with low hydrophilicity (hydrophobicity) can prevent liquid returning from the second surface 6 side, and function like a cap. In particular, when the long-fiber nonwoven fabric 20 is used as a front sheet of an absorbent article with the first surface 5 side facing the skin contact surface side, the liquid return suppression effect is high. That is, in the state where the user's skin is in contact with the front sheet, the upright fibers 4 with relatively low hydrophilicity (hydrophobicity) fall down to cover the first surface 5 side of the fiber assembly 3, so that it can perform particularly well. Liquid suppression effect. Furthermore, the erect fibers 4 are completely separated from the fiber assembly layer 3, and therefore have cushioning under pressure and give excellent touch to the skin. In addition, in the state of no pressing, as described above, even when it is not in contact with liquid, it stands up to a certain extent, so it can provide a soft skin touch that is its original function.

In the long-fiber non-woven fabric 20, this phenomenon occurs repeatedly with the supply of liquid. Thereby, the long-fiber non-woven fabric 20 with erect fibers 4 contains the above-mentioned liquid film cracking agent and has The hydrophilicity gradient not only realizes the good skin touch brought by the erect fibers 4, but also realizes the reduction of liquid residue and liquid return, and the further shortening of the liquid passing time. As a result, the long-fiber nonwoven fabric 20 as a nonwoven fabric for a front sheet can realize an excellent dry feeling that has not been available before.

Regarding the erection operation of the above-mentioned standing fibers 4, it has been confirmed by experiments that there is no erection phenomenon of the hydrophilic standing fibers, and the erection phenomenon of the hydrophobic standing fibers is generated. The so-called hydrophobicity here means that it has a low affinity with body fluids and is not easy to wet, and means that the following contact angle is 75° or more, preferably 80° or more, more preferably 85° or more, and more preferably Above 90°. The so-called hydrophilicity means that the contact angle is smaller than the above-mentioned value, and from the viewpoint of affinity with body fluids, it means that it is 90° or less.

Regarding the erection of the erect fiber 4, it is thought that it may be caused by the following factors. That is, it is considered that when the liquid is supplied to the first surface 5 and the standing fibers 4 are in contact with the hydrophilic liquid, the energy of the state where the hydrophobic standing fibers 4 are assembled with each other becomes stable, and therefore the standing fibers 4 become hydrophobic. The state where the sexual fibers 4 are gathered together, that is, the state where the hydrophobic standing fibers 4 are erected. In addition, when the standing fibers 4 are hydrophobic, it is considered that when the standing fibers 4 are supplied with liquid to the side of the first surface 5 where the standing fibers 4 are in contact with the liquid, a thin air layer is generated around the fibers. , The buoyancy works, and the erect fiber 4 is erected. Furthermore, it is believed that the erection of the erect fibers 4 when in contact with liquid is also affected by the extremely low water solubility of the liquid film cracking agent.

In addition, regarding the above-mentioned erection operation, it is believed that the difference in specific gravity is the main cause. However, in fact, even in the state where the first surface 5 side of the erecting fiber 4 is facing downward, the erection of the fiber is confirmed ( Hydrophilic standing fibers did not occur), so it is speculated that the higher specific gravity is affected by the difference in the degree of hydrophilicity.

Next, the preferred embodiment of the long-fiber nonwoven fabric of the present invention will be described. Furthermore, in any embodiment, the long-fiber non-woven fabric may be any one of a single layer and a plurality of layers. For example, Figure 1 (A) ~ (C) can be applied. In addition, regarding the gradient of the degree of hydrophilicity, the various aspects mentioned above can also be applied to Used in the embodiment shown below.

In addition to the above-mentioned hydrophilicity gradient, the long-fiber nonwoven fabric of the first embodiment also has at least one layer containing a liquid with a surface tension of 50mN/m. The spread coefficient is 15mN/m or more, and the water solubility is 0g or more and 0.025 The layer of liquid film cracking agent below g. Furthermore, a compound having the above-mentioned properties may be referred to as compound C1.

The "spreading coefficient to liquid with a surface tension of 50mN/m" of the liquid film cracking agent refers to the spreading coefficient of the liquid assumed to be excreted fluid such as menstrual blood or urine as mentioned above. The so-called "spreading coefficient" is calculated based on the following formula (1) based on the measured value obtained by the following measuring method in an environmental zone with a temperature of 25°C and a relative humidity (RH) of 65% The value. Furthermore, the liquid film in the formula (1) means the liquid phase of "a liquid with a surface tension of 50mN/m", and includes the liquid in the state where the film has been spread between the fibers or on the fiber surface, and before the film is spread The two states of liquid are also referred to as liquid for short. Moreover, the surface tension of the formula (1) means the interfacial tension at the interface between the liquid film and the liquid film cracking agent and the gas phase, which is different from the interfacial tension of the liquid film cracking agent and the liquid film between the liquid phase. This difference is also the same in other descriptions of this specification.

S=γ _w -γ _o -γ _wo (1)

γ _w : Surface tension of liquid film (liquid)

γ _o : Surface tension of liquid film cracking agent

γ _wo ：Interfacial tension between liquid film cracking agent and liquid film

According to the formula (1), the spread coefficient (S) of the liquid film cracking agent _{will become larger due to the decrease of the surface tension (γ o} ) of the liquid film cracking agent, and will increase due to the interface between the liquid film cracking agent and the liquid film The tension (γ _wo ) becomes smaller and larger. With the spreading coefficient being 15 mN/m or more, the liquid film cracking agent becomes one with higher mobility, that is, higher diffusibility, on the surface of the liquid film generated in the narrow area between the fibers. From this point of view, the spread coefficient of the liquid film cracking agent is more preferably 20 mN/m or more, still more preferably 25 mN/m or more, and particularly preferably 30 mN/m or more. On the other hand, the upper limit is not particularly limited, but according to the formula (1), when a liquid with a surface tension of 50mN/m is used, the upper limit becomes 50mN/m; when a liquid with a surface tension of 60mN/m is used In this case, the upper limit is 60mN/m; in the case of using a liquid with a surface tension of 70mN/m, the upper limit is 70mN/m, so the surface tension of the liquid forming the liquid film becomes the upper limit. Therefore, in the present invention, from the viewpoint of using a liquid with a surface tension of 50 mN/m, the upper limit of the spread coefficient is 50 mN/m or less.

The so-called "water solubility" of the liquid film cracking agent is the mass (g) of the liquid film cracking agent that can be dissolved in 100g of deionized water, and is based on the following measurement method, at a temperature of 25°C and a relative humidity (RH ) The value measured in 65% of the environmental area. When the water solubility is 0 g or more and 0.025 g or less, the liquid film cracking agent is difficult to dissolve and forms an interface with the liquid film, thereby more effectively exerting the above-mentioned diffusibility. From the same viewpoint, the water solubility of the liquid film cracking agent is preferably 0.0025 g or less, more preferably 0.0017 g or less, and still more preferably less than 0.0001 g. In addition, the water solubility is as small as possible, and it is 0 g or more. From the viewpoint of diffusibility into the liquid film, it is actually 1.0×10 ^-9 g or more. Furthermore, it is believed that the above-mentioned water solubility is also completely applicable to menstrual blood or urine with water as the main component.

_{The surface tension (γ w} ) of the above-mentioned liquid film (liquid with a surface tension of 50 mN/m), the surface tension of the liquid film cracking agent (γ _o ), the interfacial tension between the liquid film cracking agent and the liquid film (γ _wo ), and The water solubility of the liquid film cracking agent is measured by the following method.

Furthermore, when the long-fiber nonwoven fabric to be measured is a member (for example, a front sheet) incorporated in absorbent articles such as sanitary products or disposable diapers, it is taken out and measured as follows. That is, for absorbent articles, use a cooling method such as cold spray to weaken the adhesive used for joining the member of the measurement target and other members, and then carefully peel off the member of the measurement target. take out. This extraction method is suitable for the measurement of the long-fiber non-woven fabric of the present invention, such as the measurement of the distance between fibers and the fineness described below.

In addition, when measuring the liquid film cracking agent attached to the fiber, first use a cleaning solution such as hexane, methanol, ethanol, etc. to clean the fiber with the liquid film cracking agent attached to the fiber. The solvent (cleaning solvent containing the liquid film cracking agent) is dried and then taken out. The mass of the material taken out at this time is suitable for calculating the content ratio (OPU) of the liquid film cracking agent relative to the fiber mass. When the amount of the material taken out is small for the measurement of surface tension or interfacial tension, select an appropriate column and solvent according to the composition of the material taken out, and then use high performance liquid chromatography to analyze each component Distinguish, and then perform MS (mass spectrometry) measurement, NMR (nuclear magnetic resonance, nuclear magnetic resonance) measurement, elemental analysis, etc. for each component to identify the structure of each component. In addition, when the liquid film cracking agent contains a polymer compound, it becomes easier to identify the constituents by using methods such as gel permeation chromatography (GPC) in combination. And, if the substance is a commercially available product, it is purchased, and if the substance is not a commercially available product, it is synthesized to obtain a sufficient amount, and the surface tension or interfacial tension is measured. Especially when measuring surface tension and interfacial tension, when the liquid film cracking agent obtained by the above method is solid, it is heated to the melting point of the liquid film cracking agent +5°C to make the phase transfer into liquid, and then The measurement is carried out directly under the temperature condition.

(Method for measuring the surface tension (γ _{w) of liquid film (liquid))}

It can be measured with a platinum plate by the plate method (Wilhelmy method) in an environmental area with a temperature of 25°C and a relative humidity (RH) of 65%. As a measuring device at this time, an automatic surface tensiometer "CBVP-Z" (trade name, manufactured by Kyowa Interface Science Co., Ltd.) can be used. The platinum plate system uses a purity of 99.9%, a size of 25mm in length and 10mm in width.

Furthermore, in the following measurement on the liquid film cracking agent, the above-mentioned measurement method is used, In addition, the above-mentioned "liquid with a surface tension of 50mN/m" uses the following solution, which is made by adding polyoxyethylene sorbitan monolaurate as a non-ionic interfacial active substance in deionized water (for example, Kao Co., Ltd. Manufactured by the company, the trade name is RHEODOL SUPER TW-L120) and the surface tension is adjusted to 50±1mN/m.

(Measurement method of surface tension (γ _{o) of liquid film cracking agent)}

It can be measured in the same way as the measurement of the surface tension (γ _w ) of the liquid film in an environmental area with a temperature of 25° C. and a relative humidity (RH) of 65% by the flat plate method using the same device. When performing this measurement, when the liquid film cracking agent obtained as described above is solid, it is heated to the melting point of the liquid film cracking agent +5°C to make the phase transfer into liquid, and directly under the temperature condition Carry out the measurement.

(Measurement method _{of interfacial tension (γ wo} ) between liquid film cracking agent and liquid film)

It can be measured by the hanging drop method in an environment with a temperature of 25°C and a relative humidity (RH) of 65%. As a measuring device at this time, an automatic interface viscoelasticity measuring device (manufactured by TECLIS-ITCONCEPT, trade name THE TRACKER; or KRUSS, trade name DSA25S) can be used. In the pendant drop method, the non-ionic interfacial active substance contained in the liquid with a surface tension of 50 mN/m starts to be adsorbed while the drops are formed, and the interfacial tension decreases with the passage of time. Therefore, read the interfacial tension when the drop is formed (at 0 seconds). In addition, when the measurement is performed, when the liquid film cracking agent obtained as described above is a solid, it is heated to the melting point of the liquid film cracking agent +5°C to make the phase transition into liquid, and the temperature conditions Directly implement the measurement.

In addition, when measuring the interfacial tension, when the density difference between the liquid film cracking agent and the liquid with a surface tension of 50mN/m is very small, or when the viscosity is very high, if the interfacial tension value is below the measurement limit of the pendant drop agent , There are situations where the interfacial tension measurement using the pendant drop method becomes difficult. In this case, the rotary drop can be used in an environmental area with a temperature of 25°C and a relative humidity (RH) of 65%. The method is used to perform the measurement to achieve the measurement. As a measuring device at this time, a spin-drop interfacial tensiometer (manufactured by KURUSS Corporation, trade name SITE100) can be used. In addition, for this measurement, the interfacial tension when the shape of the drop is stable is also read. When the obtained liquid film cracking agent is solid, it is heated to the melting point of the liquid film cracking agent +5°C to make it phase. Transfer to a liquid, and directly perform the measurement under this temperature condition.

Furthermore, when the interfacial tension can be measured by the above-mentioned two measuring devices, the smaller interfacial tension value is used as the measurement result.

(Measurement method of water solubility of liquid film cracking agent)

In an environment with a temperature of 25°C and a relative humidity (RH) of 65%, while stirring 100g of deionized water with a stirrer, the obtained liquid film cracking agent will slowly dissolve, and it will no longer dissolve (visible suspension or precipitation, The amount of dissolution at the time of precipitation (white turbidity) is defined as water solubility. Specifically, it is measured by adding 0.0001 g each time. As a result, when it was observed that even 0.0001 g was not dissolved, it was set as "less than 0.0001 g", and when it was observed that 0.0001 g was dissolved but 0.0002 g was not dissolved, it was set as "0.0001g". Furthermore, when the liquid film cracking agent is a surfactant, the so-called "dissolution" means both monodisperse dissolution and micellar disperse dissolution, and the amount of dissolution at the time of suspension or precipitation, precipitation, and white turbidity becomes water solubility .

The liquid film cracking agent of this embodiment has the above-mentioned spread coefficient and water solubility, so that it does not dissolve but diffuses on the surface of the liquid film, and can push the layer of the liquid film from the vicinity of the center of the liquid film. This makes the liquid film unstable and cracks it.

In this embodiment, the liquid film cracking agent further preferably has an interfacial tension of 20 mN/m or less with respect to a liquid with a surface tension of 50 mN/m. _{That is, the "interfacial tension (γ wo} ) between the liquid film cracking agent and the liquid film", which defines the value of the spread coefficient (S) in the above-mentioned formula (1), is preferably 20 mN/m or less as a variable. By suppressing the "interfacial tension between the liquid film cracking agent and the liquid film (γ _wo )" to be low, and the spreading coefficient of the liquid film cracking agent is increased, the liquid film cracking agent becomes easy to move from the fiber surface to the center of the liquid film Move nearby, so that the above-mentioned effects become more obvious. From this point of view, the "interfacial tension to a liquid with a surface tension of 50mN/m" of the liquid film cracking agent is more preferably 17mN/m or less, more preferably 13mN/m or less, and still more preferably 10mN/m or less , Particularly preferably less than 9mN/m, particularly preferably less than 1mN/m. On the other hand, the lower limit is not particularly limited, and from the viewpoint of the insolubility of the liquid film, it may be greater than 0 mN/m. Furthermore, when the interfacial tension is 0 mN/m, that is, when the dissolution is performed, the interface between the liquid film and the liquid film cracking agent cannot be formed, so the formula (1) does not hold, and the expansion of the agent does not occur.

Regarding the spread coefficient, it can also be known from its mathematical formula that its value changes according to the surface tension of the target liquid. For example, when the surface tension of the target liquid is 72 mN/m, the surface tension of the liquid film cracking agent is 21 mN/m, and the interfacial tension thereof is 0.2 mN/m, the spread coefficient becomes 50.8 mN/m.

In addition, when the surface tension of the target liquid is 30 mN/m, the surface tension of the liquid film cracking agent is 21 mN/m, and the interfacial tension thereof is 0.2 mN/m, the spread coefficient becomes 8.8 mN/m.

In either case, the more the agent with the larger spreading coefficient, the better the cracking effect of the liquid film.

In this specification, the value of the surface tension of 50mN/m is defined, but even if the surface tension is different, the relationship between the values of the spreading coefficient of each substance will not change. Therefore, even if the surface tension of the body fluid is Changes in physical conditions, etc., the more the agent with a larger spreading coefficient, the more excellent the effect of liquid film cracking.

Furthermore, in this embodiment, the surface tension of the liquid film cracking agent is preferably 32 mN/m or less, more preferably 30 mN/m or less, still more preferably 25 mN/m or less, and particularly preferably 22 mN/m or less under. In addition, the lower the surface tension, the better, and the lower limit is not particularly limited. From the viewpoint of the durability of the liquid film cracking agent, it is actually 1 mN/m or more.

Next, the long-fiber nonwoven fabric of the second embodiment will be described.

In addition to the above-mentioned gradient of hydrophilicity, the long-fiber nonwoven fabric of the second embodiment also has at least one layer containing a liquid with a surface tension of 50mN/m and a spreading coefficient greater than 0mN/m, which is a positive value, and the water solubility is A layer of a liquid film cracking agent with a surface tension of 50mN/m and an interfacial tension of 20mN/m or less to a liquid with a surface tension of 50mN/m and less than 0.025g. Furthermore, a compound having the above-mentioned properties may be referred to as compound C2.

Setting the above-mentioned "interfacial tension to a liquid with a surface tension of 50 mN/m" to 20 mN/m or less means that the diffusibility of the liquid film cracking agent on the liquid film is improved as described above. As a result, even when the "spreading coefficient for liquid with a surface tension of 50mN/m" is relatively small, the spreading coefficient of 15mN/m is relatively small, due to the high diffusivity, the fiber surface is relatively small. A large amount of the liquid film cracking agent is dispersed in the liquid film, and the liquid film is pushed open at a large number of positions, whereby the same effect as in the case of the first embodiment can be exerted.

Furthermore, the so-called "spread coefficient to liquid with surface tension of 50mN/m", "water solubility" and "interfacial tension to liquid with surface tension of 50mN/m" of liquid film cracking agent are related to the first The definitions in the embodiment are the same, and the measurement methods thereof are also the same.

In this embodiment, from the viewpoint of more effectively exerting the above-mentioned effects of the liquid film cracking agent, the above-mentioned "interfacial tension to a liquid with a surface tension of 50mN/m" is preferably 17mN/m or less, more preferably 13mN /m or less, more preferably 10 mN/m or less, still more preferably 9 mN/m or less, particularly preferably 1 mN/m or less. The lower limit is not particularly limited as in the first embodiment, but from the viewpoint of not being dissolved in the liquid film (liquid with a surface tension of 50 mN/m), it is actually greater than 0 mN/m.

In addition, with regard to the "spread coefficient to a liquid with a surface tension of 50 mN/m", from the viewpoint of more effectively exerting the above-mentioned effects of the liquid film cracking agent, it is preferably 9 mN/m or more, more preferably 10 mN/m Above, it is more preferably 15 mN/m or more. The upper limit is not particularly limited, but from the viewpoint that the surface tension of the liquid forming the liquid film becomes the upper limit according to the formula (1), it is actually 50 mN/m or less.

In addition, the more preferable ranges of the surface tension and water solubility of the liquid film cracking agent are the same as in the first embodiment.

The long-fiber nonwoven fabric of the first embodiment and the long-fiber nonwoven fabric of the second embodiment preferably further contain a phosphate-type anionic surfactant in addition to the above-mentioned liquid film cracking agent. As a result, the hydrophilicity of the fiber surface is improved, and the wettability is improved, whereby the contact area between the liquid film and the liquid film cracking agent becomes larger; and, because blood or urine has a living body-derived interface active substance with a phosphate group Therefore, by using a surfactant with a phosphate group in combination, the compatibility of the active agent and the affinity with the phospholipids contained in blood or urine is also good, so the liquid film cracking agent becomes easy to move to the liquid film. And further promote the cracking of the liquid film. The content ratio of the liquid film cracking agent to the phosphate type anionic surfactant is preferably 1:1-19:1, and more preferably 2: in terms of mass ratio (liquid film cracking agent: phosphate type anionic surfactant): 1-15:1, more preferably 3:1-10:1. In particular, the aforementioned content ratio is preferably 5:1-19:1 in terms of mass ratio, more preferably 8:1-16:1, and still more preferably 11:1-13:1.

As a phosphate type anionic surfactant, it can be used without particular limitation. For example, as a specific example, alkyl ether phosphate, dialkyl phosphate, alkyl phosphate, etc. are mentioned. Among them, from the viewpoint of improving the affinity with the liquid film and imparting the function of processing the long-fiber nonwoven fabric, the alkyl phosphate is preferred.

As the alkyl ether phosphate, various ones can be used without particular limitation. For example: poly Those with saturated carbon chains, such as oxyalkylene stearyl ether phosphate, polyoxyalkylene myristyl ether phosphate, polyoxyalkylene lauryl ether phosphate, polyoxyalkylene palmityl ether phosphate, etc. ; Or polyoxyalkylene oleyl ether phosphate, polyoxyalkylene palmitate ether phosphate, etc., which have unsaturated carbon chains and those with branches in these carbon chains. More preferably, it is a fully neutralized or partially neutralized salt of a mono- or dipolyoxyalkylene alkyl ether phosphate with a carbon chain of 16-18. In addition, examples of the polyoxyethylene group include polyoxyethylene group, polyoxypropylene group, polyoxybutylene group, and those obtained by copolymerizing constituent monomers such as these. In addition, examples of salts of alkyl ether phosphates include alkali metals such as sodium and potassium, ammonia, various amines, and the like. Alkyl ether phosphate can be used alone or in combination of two or more.

Specific examples of alkyl phosphates include: stearyl phosphate, myristyl phosphate, lauryl phosphate, palmitate phosphate, and other saturated carbon chains; or oleyl phosphate, palmitate phosphate, etc. Saturated carbon chains and those having branches in these carbon chains. More preferably, it is a fully neutralized or partially neutralized salt of monoalkyl phosphate or dialkyl phosphate with a carbon chain of 16-18. In addition, examples of the salt of alkyl phosphate include alkali metals such as sodium and potassium, ammonia, various amines, and the like. Alkyl phosphate can be used alone or in combination of two or more.

Next, specific examples of the liquid film cracking agent in the first embodiment and the second embodiment will be described. Because they are within the above-mentioned specific numerical range, they will not dissolve in water or have the property of being insoluble in water, thereby exerting the effect of the above-mentioned liquid film cracking. In contrast, the surfactants used as fiber treatment agents are basically water-soluble ones that are practically dissolved in water and are not the liquid film cracking agent of the present invention.

As the liquid film cracking agent in the first embodiment and the second embodiment, a compound having a mass average molecular weight of 500 or more is preferable. The mass average molecular weight will have a greater impact on the viscosity of the liquid film cracking agent. The liquid film cracking agent maintains a high viscosity, so the liquid is not easy to flow down when passing through the fibers, so that the continuity of the liquid film cracking effect in the long-fiber non-woven fabric can be maintained. Set as sufficient From the viewpoint of the viscosity of the continuous liquid film cracking effect, the mass average molecular weight of the liquid film cracking agent is more preferably 1,000 or more, more preferably 1,500 or more, and particularly preferably 2,000 or more. On the other hand, from the viewpoint of maintaining the viscosity of the liquid film cracking agent from the fiber with the liquid film cracking agent to the liquid film, that is, the diffusibility, it is preferably 50,000 or less, more preferably 20,000 or less, and more Preferably, it is 10,000 or less. The measurement of this mass average molecular weight is measured using gel permeation chromatography (GPC) "CCPD" (trade name, manufactured by Tosoh Co., Ltd.). The measurement conditions are as follows. In addition, the calculation of the converted molecular weight was performed with polystyrene.

Separation column: GMHHR-H+GMHHR-H (cation)

Eluent: L Farmin DM20/CHCl ₃

Solvent flow rate: 1.0ml/min

Separation column temperature: 40℃

Furthermore, as the liquid film cracking agent in the first embodiment, a compound having at least one structure selected from the group consisting of the following structures X, X-Y, and Y-X-Y as described below is preferable.

Structure X represents >C(A)-(C represents a carbon atom. In addition, <,> and-represent bonding bonds. The same applies below), -C(A) ₂ -, -C(A)(B)-, >C(A)-C(R ¹ )<, >C(R ¹ )-, -C(R ¹ )(R ² )-, -C(R ¹ ) ₂ -, >C< and -Si(R _{^{1) 2 O -, - Si}} (R 1) (R 2) O- in any repetition of a basic structure, or a combination of silicon oxide formed by two or more alkyl chains of the structure, the chain or mixtures thereof. It has a hydrogen atom at the end of structure X, or is selected from -C(A) ₃ , -C(A) ₂ B, -C(A)(B) ₂ , -C(A) ₂ -C(R ¹ ) ₃ , -C(R ¹ ) ₂ A, -C(R ¹ ) ₃ , and -OSi(R ¹ ) ₃ , -OSi(R ¹ ) ₂ (R ² ), -Si(R ¹ ) ₃ , -Si( At least one group in the group consisting of R ¹ ) ₂ (R ^{2 ).}

The above-mentioned R ¹ or R ² each independently represents a hydrogen atom, an alkyl group (preferably with a carbon number of 1 to 20. For example, a methyl group, an ethyl group, or a propyl group is preferable), and an alkoxy group (preferably with a carbon number of 1 ~20. For example, preferably methoxy, ethoxy), aryl (preferably carbon number 6-20. For example, preferably phenyl), halogen atom (for example, preferably fluorine atom) and other substituents . A and B each independently represent a substituent containing an oxygen atom or a nitrogen atom, such as a hydroxyl group or a carboxylic acid group, an amino group, an amide group, an imino group, and a phenol group. ^{When there are a plurality of R 1} , R ² , A, and B in the structure X, they may be the same or different from each other. In addition, the bond between the connected C (carbon atom) or Si is usually a single bond, but may also include a double bond or a triple bond, and the bond between C or Si may also include an ether group (-O-), an amide group (-CONR ^a -: R ^a based hydrogen atom or a monovalent group), an ester group (-COO-), carbonyl (-CO-), a carbonate group (-OCOO-) and the like linking group. The number of bonds between one C and Si and another C or Si is 1~4, so there can also be long-chain polysiloxane chains (siloxane chains) or mixed chain branches, or have radial structures situation.

Y represents a hydrophilic group containing an atom selected from a hydrogen atom, a carbon atom, an oxygen atom, a nitrogen atom, a phosphorus atom, and a sulfur atom. For example, hydroxyl group, carboxylic acid group, amino group, amide group, imine group, phenol group, polyoxyalkylene group (the carbon number of oxyalkylene group is preferably 1 to 4. For example, polyoxyethylene group is preferred. (POE) group, polyoxypropylene (POP) group), sulfonic acid group, sulfuric acid group, phosphoric acid group, sulfobetaine group, carbonyl betaine base, phosphinobetaine base (their betaine base refers to each A betaine compound is a betaine residue obtained by removing one hydrogen atom), a hydrophilic group such as a quaternary ammonium group alone or a hydrophilic group including a combination thereof. In addition to these, the groups and functional groups ^{listed in M 1 below can also be cited.} Furthermore, when Y is plural, they may be the same or different.

In the structures X-Y and Y-X-Y, Y is the group bonded to X or the end of X. In the case where Y is bonded to the terminal group of X, the terminal group of X is bonded to Y by removing, for example, the same number of hydrogen atoms as the number of bonding with Y.

In this structure, the hydrophilic groups Y, A, and B are selected from the specifically described groups to satisfy the above-mentioned spreading coefficient, water solubility, and interfacial tension. This shows the target liquid film cracking effect.

The above-mentioned liquid film cracking agent is preferably a compound whose structure X is a siloxane structure. Furthermore, the liquid film cracking agent preferably includes the following (1) as specific examples of the above-mentioned structures X, X-Y, and Y-X-Y. (11) Compounds of siloxane chains formed by arbitrarily combining the structures represented by the formula. Furthermore, from the viewpoint of the cracking effect of the liquid film, it is preferable that the compound has a mass average molecular weight in the above-mentioned range.

In formulas (1) to (11), M ¹ , L ¹ , R ²¹ , and R ²² represent the following monovalent or polyvalent (divalent or more than divalent) groups. R ²³ and R ²⁴ represent the following monovalent or polyvalent (divalent or more than divalent) group or single bond.

M ¹ represents a group having polyoxyethylene, polyoxypropylene, polyoxyethylene, or a combination of polyoxyethylene groups; or erythritol group, xylitol group, Hydrophilic groups with multiple hydroxyl groups such as sorbitol, glycerol, or glycol groups (hydrophilic groups formed by removing one hydrogen atom from the above compounds with multiple hydroxyl groups such as erythritol), hydroxyl, carboxylic acid Group, mercapto group, alkoxy group (preferably carbon number 1-20. For example, methoxy group is preferable), amino group, amide group, imino group, phenol group, sulfonic acid group, quaternary ammonium group, sulfonic acid group Betaine base, hydroxysultaine base, phosphinobetaine base, imidazolium betaine base, carbonyl betaine base, epoxy group, methanol base, (meth)acrylic group, or a combination thereof的functional group. Furthermore, when M ¹ is a multivalent group, M ¹ represents a group obtained by removing one or more hydrogen atoms from each of the above-mentioned groups or functional groups.

L ¹ represents an ether group, an amino group (the amino group that can be used as L ¹ is represented by >NR ^C (R ^C represents a hydrogen atom or a monovalent group)), a bond between an amino group, an ester group, a carbonyl group, and a carbonate group Foundation.

R ²¹ , R ²² , R ²³ , and R ²⁴ each independently represent an alkyl group (preferably carbon number 1-20. For example, methyl, ethyl, propyl, isopropyl, butyl, pentyl are preferred , Hexyl, heptyl, 2-ethylhexyl, nonyl, decyl), alkoxy (preferably carbon number 1-20. For example, preferably methoxy, ethoxy), aryl (preferably It has a carbon number of 6 to 20. For example, a phenyl group, a fluoroalkyl group, or an aralkyl group, or a hydrocarbon group formed by combining them, or a halogen atom (for example, a fluorine atom is preferable). In addition, when R ²² and R ²³ are polyvalent groups, it means a polyvalent hydrocarbon group obtained by removing one or more hydrogen atoms or fluorine atoms from the above-mentioned hydrocarbon group.

In addition, when R ²² or R ²³ is bonded to M ¹ , the groups that can be used as R ²² or R ²³ include the above-mentioned groups, the above-mentioned hydrocarbon groups, or halogen atoms, as well as the imines ^{that can be used as R 32} base.

Regarding the liquid film cracking agent, among them, the following compound is preferred, the compound having a structure represented by any one of formulas (1), (2), (5) and (10) as X, and having its equation The structure represented by any one of the above formulas other than that is used as the end of X, or includes the end of X and the group of Y. More preferably, the compound contains a group having X or a terminal containing X and Y from among the above formulas (2), (4), (5), (6), (8) and (9) Any one of the structures represented by at least one siloxane chain.

As a specific example of the above compound, an organically modified polysiloxane (polysiloxane) which is a polysiloxane-based surfactant can be cited. For example, as an organic modified polysiloxane modified with a reactive organic group, examples include: amine group modifier, epoxy modifier, carboxyl group modifier, glycol modifier, methanol modifier, ( Meth) acrylic modifier, mercapto modifier, phenol modifier. In addition, as an organically modified polysiloxane modified by a non-reactive organic group, there can be cited: polyether modified (including polyoxyethylene Modifier), methylstyrene modifier, long-chain alkyl modifier, higher fatty acid ester modifier, higher alkoxy modifier, higher fatty acid modifier, fluorine modifier, etc. . Depending on the type of organic modification, for example, by appropriately changing the molecular weight of the polysiloxane chain, the modification rate, and the number of moles of addition of the modified group, the spread coefficient that exerts the above-mentioned liquid film cracking effect can be obtained. . Here, the "long chain" refers to those having 12 or more carbon atoms, preferably 12-20. In addition, the term "high-grade" refers to those having 6 or more carbon atoms, preferably 6-20.

Among them, polyoxyalkylene-modified polysiloxane or epoxy-modified polysiloxane, methanol-modified polysiloxane, glycol-modified polysiloxane, etc., as the liquid film cracking agent of modified polysiloxane, are preferably The modified polysiloxane having a structure having at least one oxygen atom in the modifying group is particularly preferably a polyoxyalkylene modified polysiloxane. The polyoxyalkylene-modified polysiloxane has a polysiloxane chain, so it is difficult to penetrate into the inside of the fiber and is likely to remain on the surface. In addition, the hydrophilic polyoxyalkylene chain is added, so the affinity with water is improved, and the interfacial tension is low, and therefore it is easy to move on the surface of the above-mentioned liquid film, which is preferable. Therefore, it is easy to move on the surface of the above-mentioned liquid film, which is preferable. In addition, even if hot melt processing such as embossing is performed, the polyoxyalkylene-modified polysiloxane is likely to remain on the surface of the fiber in this part, and the cracking effect of the liquid film is not easily reduced. Especially in the embossing part where liquid is easy to accumulate, the cracking effect of the liquid film will be fully expressed, so it is better.

Examples of the polyoxyalkylene-modified polysiloxane include those represented by the following formulas [I] to [IV]. Furthermore, from the viewpoint of the cracking effect of the liquid film, it is preferable that the polyoxyalkylene-modified polysiloxane has a mass average molecular weight in the above-mentioned range.

[化3]

In the formula, R ³¹ represents an alkyl group (preferably with a carbon number of 1-20. For example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, 2-ethyl are preferred. Hexyl, nonyl, decyl). R ³² represents a single bond or an alkylene group (preferably with a carbon number of 1 to 20. For example, methylene, ethylene, propylene, and butylene are preferred), and preferably represents the above-mentioned alkylene. The plurality of R ³¹ and the plurality of R ³² may be the same or different from each other. M ¹¹ represents a group having a polyoxyalkylene group, preferably a polyoxyalkylene group. Examples of the above-mentioned polyoxyalkylene group include polyoxyethylene group, polyoxypropylene group, polyoxybutylene group, and those obtained by copolymerizing constituent monomers such as these. m and n are each independently an integer of 1 or more. Furthermore, the symbols of the repeating units are determined separately in each of formulas (I) to (IV), and may not necessarily represent the same integer, but may be different.

In addition, the polyoxyalkylene-modified polysiloxane may have either or both of a polyoxyethylene-modified group and a polyoxyethylene-modified group. In addition, in order to be insoluble in water and have a lower interfacial tension, it is more desirable that the alkyl group R ³¹ in the silicone chain has a methyl group. There are no particular limitations on the one having the modifying group and the polysiloxane chain. For example, there are those described in paragraphs [0006] and [0012] of JP 2002-161474. More specifically, it can include: polyoxyethylene (POE) polyoxypropylene (POP) modified polysiloxane, or polyoxyethylene (POE) modified polysiloxane, polyoxyethylene propylene (POP) Modified polysiloxane, etc. As the POE modified polysiloxane, POE(3) modified dimethyl polysiloxane added with 3 mol of POE can be cited. As the POP modified polysiloxane, there can be mentioned: POP(10) modified dimethyl polysiloxane with addition of 10 mol, 12 mol, or 24 mol of POP, and POP(12) modified dimethyl polysiloxane Based polysiloxane, POP (24) modified dimethyl polysiloxane, etc.

Regarding the spreading coefficient and water solubility of the above-mentioned first embodiment, in the case of polyoxyalkylene-modified polysiloxane, for example, it can be based on the addition molar number of polyoxyalkylene (to polyoxyalkylene). The number of oxyalkylene-forming polyoxyalkylene bonds of 1 mol of modified polysiloxane, the following modification rate, etc., are set to specific ranges. In this liquid film cracking agent, similarly to the surface tension and the interfacial tension, each may be set to a specific range.

From the above viewpoint, it is preferable that the number of addition moles of the polyoxyalkylene group is 1 or more. If it does not reach 1, the above-mentioned liquid film cracking effect will be due to higher interfacial tension and smaller spreading coefficient, so the liquid film cracking effect becomes weaker. From this viewpoint, the number of addition moles is more preferably 3 or more, and still more preferably 5 or more. On the other hand, if the number of added moles is too large, it becomes hydrophilic and the water solubility becomes high. From this viewpoint, the number of addition moles is preferably 30 or less, more preferably 20 or less, and still more preferably 10 or less.

Regarding the modification rate of the modified silicone, if it is too low, the hydrophilicity is impaired, so it is preferably 5% or more, more preferably 10% or more, and still more preferably 20% or more. Moreover, if it is too high, it will dissolve in water, so it is preferably 95% or less, more preferably 70% or less, and still more preferably 40% or less. Furthermore, the so-called modification rate of the above-mentioned modified silicone refers to the number of repeating units of the modified silicone bonding part in 1 molecule of the modified silicone relative to the number of the silicone bonding part The ratio of the total number of repeating units. For example, in the above formula [I] and [IV], it is (n/m+n)×100%, in the formula [II] it is (2/m)×100%, in the formula [III] it is (1/ m)×100%.

In addition, with regard to the aforementioned spreading coefficient and water solubility, in the case of polyoxyalkylene-modified polysiloxane, in addition to the above, they can also be set to specific ranges by the following methods: and water-soluble Polyoxyethylene and water-insoluble polyoxypropylene and polyoxyethylene butyl groups are used as modified groups; to change the molecular weight of water-insoluble polysiloxane chains; and in addition to polyoxyethylene modified groups, also Amino groups, epoxy groups, carboxyl groups, hydroxyl groups, methanol groups, etc. are introduced as modifying groups and the like.

The polyalkylene-modified polysiloxane that can be used as a liquid film cracking agent preferably contains 0.02 mass% or more and 5 mass% or less in terms of the content ratio (Oil Per Unit) relative to the fiber mass. The content ratio (OPU) of the polyalkylene-modified polysiloxane is more preferably 1% by mass or less, and still more preferably 0.4% by mass or less. Thereby, the long-fiber non-woven fabric has a better tactile feel. In addition, from the viewpoint of sufficiently exhibiting the liquid film cracking effect of the polyalkylene-modified polysiloxane, the content ratio (OPU) is more preferably 0.04% by mass or more, and more preferably 0.1% by mass or more.

The liquid film cracking agent in the second embodiment is preferably a compound having at least one structure selected from the group consisting of the following structures Z, Z-Y, and Y-Z-Y as described below.

Structure Z means that >C(A)-(C: carbon atom), -C(A) ₂ -, -C(A)(B)-, >C(A)-C(R ³ )<, >C (R ³ )-, -C(R ³ )(R ⁴ )-, -C(R ³ ) ₂ -, >C< any one of the basic structure repeats, or a combination of two or more of the structure formed by the hydrocarbon chain . It has a hydrogen atom at the end of structure Z, or is selected from -C(A) ₃ , -C(A) ₂ B, -C(A)(B) ₂ , -C(A) ₂ -C(R ³ ) ₃ , -C(R ³ ) ₂ A, -C(R ³ ) ₃ at least one group in the group.

The above-mentioned R ³ or R ⁴ each independently represents a hydrogen atom, an alkyl group (preferably with a carbon number of 1 to 20. For example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, and hexyl are preferred). , Heptyl, 2-ethylhexyl, nonyl, decyl), alkoxy (preferably carbon number 1-20. For example, preferably methoxy, ethoxy), aryl (preferably carbon The number is 6 to 20. For example, a phenyl group, a fluoroalkyl group, an aralkyl group, or a combination thereof, a hydrocarbon group, or various substituents such as a fluorine atom are preferable. A and B each independently represent a substituent containing an oxygen atom or a nitrogen atom, such as a hydroxyl group or a carboxylic acid group, an amino group, an amide group, an imino group, and a phenol group. ^{When there are a plurality of R 3} , R ⁴ , A, and B in the structure Z, they may be the same or different from each other. In addition, the bond between the connected C (carbon atom) is usually a single bond, but may also include a double bond or a triple bond, and the bond between C may also include an ether group, an amido group, an ester group, a carbonyl group, and a carbonate group. Etc. link base. The number of bonds between one C and the other C is 1~4, so there may be long-chain hydrocarbon chain branching or a radial structure.

Y represents a hydrophilic group containing an atom selected from a hydrogen atom, a carbon atom, an oxygen atom, a nitrogen atom, a phosphorus atom, and a sulfur atom. For example, it contains a hydroxyl group, a carboxylic acid group, an amino group, an amide group, an imine group, a phenol group; or a polyoxyalkylene group (the carbon number of the oxyalkylene group is preferably 1 to 4. For example, a polyoxyalkylene group is preferable). Ethylene, polyoxypropylene, polyoxyethylene, or polyoxyethylene group formed by combining them); or erythritol, xylitol, sorbitol, glycerol , Ethylene glycol group and other hydrophilic groups with multiple hydroxyl groups; or sulfonic acid group, sulfate group, phosphoric acid group, sulfobetaine group, carbonyl betaine group, phosphonobetaine group, quaternary ammonium group, imidazolium beet Hydrophilic groups such as bases, epoxy groups, methanol groups, and methacrylic groups alone; or a combination of these hydrophilic groups. Furthermore, when Y is plural, they may be the same or different.

In the structures Z-Y and Y-Z-Y, Y is the group bonded to the end of Z or Z. In the case where Y is bonded to the terminal group of Z, the terminal group of Z is bonded to Y by removing, for example, the same number of hydrogen atoms as the number of bonding with Y.

In this structure, the hydrophilic groups Y, A, and B are selected from the specifically described groups to satisfy the above-mentioned spreading coefficient, water solubility, and interfacial tension. This shows the target liquid film cracking effect.

The above-mentioned liquid film cracking agent is preferably a compound formed by arbitrarily combining the structures represented by the following formulas (12) to (25), which are specific examples of the above-mentioned structures Z, Z-Y, and Y-Z-Y. Furthermore, from the viewpoint of the cracking effect of the liquid film, it is preferable that the compound has a mass average molecular weight in the above-mentioned range the amount.

In formulas (12) to (25), M ² , L ² , R ⁴¹ , R ⁴² , and R ⁴³ represent the following monovalent or multivalent groups (divalent or more than divalent).

M ² represents a group having polyoxyethylene, polyoxyethylene, polyoxyethylene, or a combination of polyoxyethylene groups; or erythritol group, xylitol group, Hydrophilic groups having multiple hydroxyl groups, such as sorbitol group, glyceryl group or glycol group, etc., hydroxyl group, carboxylic acid group, mercapto group, alkoxy group (preferably carbon number 1-20. For example, preferably methoxy group) , Amine group, amide group, imino group, phenol group, sulfonic acid group, quaternary ammonium group, sultaine group, hydroxy sultaine group, phosphonobetaine group, imidazolium betaine group, carbonyl group Betaine group, epoxy group, methanol group, (meth)acrylic group, or functional group formed by combining them.

L ² represents ether group, amine group, amide group, ester group, carbonyl group, carbonate group, or polyoxyethylene, polyoxypropylene, polyoxyethylene, or a combination thereof. Bonding groups such as oxyalkylene groups.

R ⁴¹ , R ⁴² , and R ⁴³ each independently represent a hydrogen atom, an alkyl group (preferably carbon number 1-20. For example, methyl, ethyl, propyl, isopropyl, butyl, pentyl Group, hexyl, heptyl, 2-ethylhexyl, nonyl, decyl), alkoxy (preferably carbon number 1-20. For example, preferably methoxy, ethoxy), aryl (more Preferably, the number of carbon atoms is 6 to 20. For example, a phenyl group, a fluoroalkyl group, an aralkyl group, or a hydrocarbon group formed by combining them, or various substituents of a halogen atom (for example, a fluorine atom is preferable) are preferable.

When R ⁴² is a polyvalent group, R ⁴² represents a group obtained by removing one or more hydrogen atoms from each of the above-mentioned substituents.

Furthermore, other structures can be arbitrarily connected before the bonding bond described in each structure, and a hydrogen atom can also be introduced.

Furthermore, as a specific example of the said compound, the following compounds can be mentioned, but it is not limited to these.

First, a polyether compound or a nonionic surfactant can be mentioned. Specifically, examples include: polyoxyalkylene (POA) alkyl ethers represented by any one of the formula (V), or polyoxyalkylene dialkylenes with a mass average molecular weight of 1,000 or more represented by the formula (VI) Alcohol, stearyl ether, behenyl ether, PPG myristyl ether, PPG stearyl ether, PPG behenyl ether, etc. As the polyoxyalkylene alkyl ether, lauryl ether with POP added with 3 mol or more and 24 mol or less, preferably 5 mol, is preferred. As the polyether compound, it is preferably polypropylene glycol (PPG) with an addition of 17 mol or more and 180 mol or less, preferably about 50 mol. The mass average molecular weight of polypropylene glycol (PPG) is 1,000 to 10,000, preferably 3,000. Wait. Furthermore, the measurement of the above-mentioned mass average molecular weight can be performed by the above-mentioned measurement method.

The polyether compound or nonionic surfactant is preferably contained in a content ratio (Oil Per Unit) relative to the fiber mass of 0.10% by mass or more and 5% by mass or less. The content ratio (OPU) of the polyether compound or nonionic surfactant is more preferably 1% by mass or less, and still more preferably 0.4% by mass or less. In this way, the non-woven fabric has a better tactile feel. In addition, from the viewpoint of sufficiently exhibiting the liquid film cracking effect of the polyether compound or nonionic surfactant, the content ratio (OPU) is more preferably 0.15% by mass or more, and even more preferably 0.2% by mass or more.

In the formula, L ²¹ represents ether group, amino group, amide group, ester group, carbonyl group, carbonate group, polyoxyethylene group, polyoxyethylene group, polyoxyethylene group, or a combination thereof The polyoxyalkylene and other bonding groups. R ⁵¹ represents a hydrogen atom, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, decyl, methoxy, ethoxy , Phenyl, fluoroalkyl, aralkyl, or a combination of these and other hydrocarbon groups, or various substituents of fluorine atoms. In addition, a, b, m, and n are each independently an integer of 1 or more. Here, C _m H _n represents an alkyl group (n=2m+1), and C _a H _b represents an alkylene group (a=2b). Furthermore, the number of carbon atoms and the number of hydrogen atoms are determined independently in each of the formulas (V) and (VI), and they do not necessarily represent the same integer, and may be different. Hereinafter, m, m', m", n, n', and n" in formulas (VII)~(XV) are also the same. Furthermore, "m" of -(C _a H _b O) _m -is an integer of 1 or more. The value of the repeating unit is determined independently in each of the formulas (V) and (VI), and does not necessarily represent the same integer, and may be different.

Regarding the spreading coefficient, surface tension, and water solubility of the above-mentioned second embodiment, in the case of a polyether compound or a nonionic surfactant, it can be set to a specific range, for example, according to the number of moles of the polyoxyalkylene group, etc. . From this viewpoint, it is preferable that the molar number of the polyoxyalkylene group is 1 or more and 70 or less. By setting it to 1 or more, the above-mentioned liquid film cracking effect can be fully exerted. From this viewpoint, the number of moles is more preferably 5 or more, and still more preferably 7 or more. On the other hand, the number of added moles is preferably 70 or less, more preferably 60 or less, and still more preferably 50 or less. Thereby, the connection of the molecular chain is weakened moderately, and the diffusibility in the liquid film is excellent, which is preferable.

In addition, the above-mentioned spreading coefficient, surface tension, interfacial tension and water solubility can be set to specific ranges in the case of polyether compounds or non-ionic surfactants respectively by the following methods: and using water-soluble polyoxygen Ethylene and water-insoluble polyoxypropylene and polyoxyethylene; change the chain length of the hydrocarbon chain; use the hydrocarbon chain with branch; use the hydrocarbon chain with double bond; use the hydrocarbon chain with benzene ring or Those with naphthalene ring; or appropriate combination of the above.

Secondly, hydrocarbon compounds having 5 or more carbon atoms can be cited. From the viewpoint that the liquid is easier to expand on the surface of the liquid film, the number of carbon atoms is preferably 100 or less, and more preferably 50 or less. The hydrocarbon compound excluding polyorganosiloxane is not limited to a straight chain, but may be a branched chain, and the chain is not particularly limited to a saturated chain or an unsaturated chain. In addition, it may have substituents such as esters or ethers in the middle and at the ends. Among them, those that are liquid at room temperature may preferably be used alone. The hydrocarbon compound is preferably contained in a content ratio (Oil Per Unit) relative to the fiber mass of 0.1% by mass or more and 5% by mass or less. The content ratio (OPU) of the hydrocarbon compound is preferably 1% by mass or less, more preferably 0.99% by mass or less, and still more preferably 0.4% by mass or less. Thereby, the long-fiber non-woven fabric has a better tactile feel. In addition, from the viewpoint of fully exerting the cracking effect of the liquid film based on the hydrocarbon compound, the above The content ratio (OPU) is more preferably 0.15% by mass or more, and still more preferably 0.2% by mass or more.

Examples of the hydrocarbon compound include oil or fat, such as natural oil or natural fat. Specific examples include coconut oil, camellia oil, castor oil, coconut palm oil, corn oil, olive oil, sunflower oil, tall oil, and mixtures thereof.

In addition, fatty acids represented by the formula (VII), such as caprylic acid, capric acid, oleic acid, lauric acid, palmitic acid, stearic acid, myristic acid, behenic acid, and mixtures thereof, can be cited.

[化9] C _m H _n -COOH [VII]

In the formula, m and n are each independently an integer of 1 or more. Here, C _m H _n represents the hydrocarbon group of each of the above-mentioned fatty acids.

As examples of linear or branched, saturated or unsaturated, substituted or unsubstituted polyhydric alcohol fatty acid esters or mixtures of polyhydric alcohol fatty acid esters, such as formula (VIII-I) or (VIII-II) The glycerol fatty acid ester or pentaerythritol fatty acid ester represented by) specifically includes glyceryl tricaprylate, glyceryl tripalmitate, and mixtures thereof. Furthermore, the mixture of glycerol fatty acid esters or pentaerythritol fatty acid esters typically includes several monoesters, diesters, and triesters. As a preferable example of glycerin fatty acid ester, glycerin tricaprylate, a mixture of glycerin tricaprylate, etc. are mentioned. In addition, from the viewpoint of lowering the interfacial tension and obtaining a higher spread coefficient, polyol fatty acid esters in which polyoxyalkylene groups are introduced to the extent that water insolubility can be maintained can also be used.

In the formula, m, m', m", n, n', and n" are each independently an integer of 1 or more. The plural m and the plural n may be the same or different from each other. _{Here, C m H n, C m} 'H n' and C _m "H _n" each denote a hydrocarbon group of a fatty acid.

As an example of a fatty acid or a fatty acid mixture in which a linear or branched, saturated or unsaturated fatty acid forms an ester with a polyhydric alcohol having multiple hydroxyl groups, and a part of the hydroxyl groups is not esterified but remains, the following examples include: Any one, any one of formula (X), or any one of formula (XI) represented by glycerin fatty acid ester, or a partial ester product of sorbitan fatty acid ester and pentaerythritol fatty acid ester. Specifically, examples include: ethylene glycol monomyristate, ethylene glycol dimyristate, ethylene glycol palmitate, ethylene glycol dipalmitate, glyceryl dimyristate, glycerol dipalmitate Acid ester, glycerol monooleate, sorbitan monooleate, sorbitan monostearate, sorbitan dioleate, sorbitan tristearate, pentaerythritol monostearate, pentaerythritol Dilaurate, pentaerythritol tristearate, and mixtures thereof, etc. Furthermore, with regard to a mixture containing glycerin fatty acid esters, sorbitan fatty acid esters, pentaerythritol fatty acid esters, etc., a partial esterification product, typically, it contains several fully esterified compounds.

In the formula, m and n are each independently an integer of 1 or more. The plural m and the plural n may be the same or different from each other. Here, C _m H _n represents the hydrocarbon group of each of the above-mentioned fatty acids.

In the formula, R ⁵² represents a linear or branched, saturated or unsaturated hydrocarbon group (alkyl, alkenyl, alkynyl, etc.) having 2 or more and 22 or less carbon atoms. Specifically, 2-ethylhexyl, lauryl, myristyl, palmityl, stearyl, behenyl, oleyl, linseed, etc. can be mentioned.

In the formula, m and n are each independently an integer of 1 or more. The plural m and the plural n may be the same or different from each other. Here, C _m H _n represents the hydrocarbon group of each of the above-mentioned fatty acids.

In addition, sterols, phytosterols, and sterol derivatives can be cited. Specific examples include cholesterol, sitosterol, stigmasterol, ergosterol, and mixtures thereof having a sterol structure of formula (XII).

Specific examples of alcohols include: lauryl alcohol, myristyl alcohol, Cetyl alcohol, stearyl alcohol, cetearyl alcohol, behenyl alcohol, and mixtures thereof.

[化16] C _m H _n -OH [XIII]

In the formula, m and n are each independently an integer of 1 or more. Here, C _m H _n represents the hydrocarbon group of each of the above-mentioned alcohols.

Specific examples of fatty acid esters include: isopropyl myristate, isopropyl palmitate, cetyl ethylhexanoate, glyceryl triisocaprylate, and octyl myristate represented by formula (XIV) Lauryl ester, ethylhexyl palmitate, ethylhexyl stearate, butyl stearate, myristyl myristate, stearyl stearate, cholesteryl isostearate and the like And other mixtures, etc.

[化17] C _m H _n -COO-C _m H _n [XIV]

In the formula, m and n are each independently an integer of 1 or more. Here, the two C _m H _n may be the same or different. C _m H _n -COO- C _m H _n denotes the above-mentioned hydrocarbon group for each of the fatty acid. -COOC _m H _n C _m H _n represents the hydrocarbon group of the alcohol from the ester formed.

In addition, as specific examples of waxes, ceresin, paraffin, petrolatum, mineral oil, fluid isoparaffin, and the like represented by the formula (XV) can be cited.

[化18] C _m H _n [XV]

In the formula, m and n are each independently an integer of 1 or more.

Regarding the spread coefficient, surface tension, water solubility, and interfacial tension of the above-mentioned second embodiment, in the case of the above-mentioned hydrocarbon compounds with 5 or more carbon atoms, they can be set to specific ranges by the following methods: for example, a small amount The introduction of hydrophilic polyoxyethylene to the extent that it can maintain water insolubility; the introduction of polyoxyethylene or polyoxyethylene which is hydrophobic but can reduce the interfacial tension Group; change the chain length of the hydrocarbon chain; use those with branched hydrocarbon chains; use those with double bonds in hydrocarbon chains; use those with benzene ring or naphthalene ring, etc.

In the long-fiber nonwoven fabric of the present invention, in addition to the above-mentioned liquid film cracking agent, other ingredients may be contained as needed. In addition, the liquid film cracking agent of the first embodiment and the liquid film cracking agent of the second embodiment may be used in combination of the two agents in addition to the respective forms used. This aspect is also the same for the first compound and the second compound in the liquid film cracking agent of the second embodiment.

Furthermore, when identifying the liquid film cracking agent or phosphate anionic surfactant contained in the long-fiber nonwoven fabric of the present invention, the liquid film (liquid with a surface tension of 50 mN/m) can be used. The identification method described in the measurement method of surface tension (γ _{w ), etc.}

In addition, when the composition of the liquid film cracking agent is a compound having a silicone chain in the main chain or a hydrocarbon compound having 1 or more and 20 carbon atoms, the content ratio of the liquid film cracking agent to the fiber mass (OPU) can be It is determined by the following method: Based on the mass of the substance obtained by the above analysis method, the content of the liquid film cracking agent is divided by the mass of the fiber.

Next, the degree of hydrophilicity in the long-fiber nonwoven fabric of the present invention will be described in more detail.

The degree of hydrophilicity is the degree of hydrophilicity of the constituent fibers, which can be judged by using the contact angle of deionized water with respect to the constituent fibers as an index. The contact angle is the angle between the fibrous water droplet and the fiber surface, and the decrease in the degree of hydrophilicity has the same meaning as the increase in the contact angle. The contact angle can be obtained by the measurement method described below.

In the long-fiber nonwoven fabric of the present invention, when there is a hydrophilicity gradient in the thickness direction from the first surface side, which is the liquid receiving surface side (skin contact surface side), to the second surface side (non-skin contact surface side), From the viewpoint of reducing the amount of liquid adhering to the skin, the contact angle (V1) of the fibers on the first surface side is preferably 80° or more, more preferably 85° or more, and still more preferably 90° or more. In addition, the above-mentioned contact angle (V1) is preferably 100° or less, more preferably 97° or less, and still more preferably 95° or less from the viewpoint of preventing the flow of liquid on the surface.

On the other hand, the contact angle (V2) of the fibers on the second surface side (non-skin contact surface side) is preferably 90° or less, more preferably 85°, from the viewpoint of improving the suction performance of the liquid. ° or less, more preferably 80 ° or less. In addition, the contact angle (V2) is preferably 30° or more, more preferably 40° or more from the viewpoint of improving the liquid transferability to the absorbent body in a state where the surface sheet is placed on the absorbent body. , And more preferably 50° or more.

Furthermore, the difference (V1-V2) between the contact angle (V1) of the fiber on the first surface side and the contact angle (V2) of the fiber on the second surface side (non-skin contact surface side) (V1-V2) increases the liquid direction From the viewpoint of permeability in the thickness direction, it is preferably 3° or more, more preferably 5°, and still more preferably 10°. In addition, the above-mentioned difference in contact angle (V1-V2) is preferably 5° or more, more preferably 7°, and still more preferably 10 from the viewpoint of both the permeability of the liquid in the thickness direction and the difficulty of liquid return. °.

(Method of measuring contact angle)

The above-mentioned contact angle can be measured by the following method.

That is, the fiber is taken out from a specific part of the long-fiber nonwoven fabric, and the contact angle of water with respect to the fiber is measured. The automatic contact angle meter MCA-J manufactured by Concord Interface Science Co., Ltd. was used as the measuring device. Distilled water is used in the measurement of contact angle. It is carried out under the measurement conditions of a temperature of 25°C and a relative humidity (RH) of 65%. The amount of liquid ejected from the ink jet water droplet ejection unit (Cluster Technology, pulse jet CTC-25 with an aperture of 25 μm) was set to 20 microliters, and water droplets were dropped directly above the fiber. Record the dripping situation in a high-speed recording device connected to a horizontally set camera. Regarding the video recording device, from the viewpoint of subsequent image analysis, a personal computer equipped with a high-speed capture device is more desirable. In this measurement, the image was recorded every 17msec. In the recorded image, the initial image when water droplets are dropped onto the fiber taken out of the laminated non-woven fabric uses the attached software FAMAS (set: the software version is 2.6.2, the analytical method is the droplet method, and the analytical method is θ/ 2 method, the image processing algorithm is none For reflection, the image processing image mode is a frame, the threshold level is 200, and the curvature correction is not performed.) Perform image analysis to calculate the angle between the surface of the water droplet in contact with the air and the fiber, and set it as the contact angle. The fiber taken out from the laminated non-woven fabric is cut to a fiber length of 1 mm, and the fiber is placed on the sample table of the contact angle meter and maintained horizontally. The contact angles of two different parts of each fiber are measured. Measure the contact angle of N=5 to one digit below the decimal point. The value obtained by averaging the measured values of 10 points (rounded to the second digit below the decimal point) is defined as the contact angle.

As the hydrophilizing agent that imparts the above-mentioned contact angle, the user of such an article can be used without particular limitation. Specifically, for example, anionic, cationic, amphoteric and nonionic surfactants can be used. Anionic surfactants of carboxylate series, anionic surfactants of sulfonate series, and sulfate ester salt series can be used. Anionic surfactants, phosphate anionic surfactants (especially alkyl phosphate salts) and other anionic surfactants; sorbitan fatty acid esters, diethylene glycol monostearate, diethylene glycol Monooleate, glycerol monostearate, glycerol monooleate, propylene glycol monostearate and other polyhydric alcohol monofatty acid esters, oleic acid amide, stearic acid amide, erucic acid amide and other fatty acid esters Amine, N-(3-oleyloxy-2-hydroxypropyl)diethanolamine, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitol beeswax, polyoxyethylene sorbitan sesquistearate, polyoxyethylene sorbitan Oxyethylene monooleate, polyoxyethylene sorbitan sesquistearate, polyoxyethylene glycerol monooleate, polyoxyethylene monostearate, polyoxyethylene monolaurate, polyoxyethylene mono Nonionic surfactants such as oleate, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether; cationic surfactants such as quaternary ammonium salt, amine salt or amine; containing carboxyl group, sulfonate group, and sulfate ester Amphoteric surfactants such as aliphatic derivatives of secondary amines or tertiary amines, or aliphatic derivatives of heterocyclic secondary amines or tertiary amines. The combination of the preferred surfactants and the preferred surfactants only needs to include the surfactants, and may further include other surfactants. Moreover, the so-called phosphate ester type anionic surfactant is actually compatible with the above-mentioned liquid membrane The cracking agent contains the same agents as the phosphate ester type anionic surfactants listed. That is, the phosphate type anionic surfactant has the following two functions, namely, the function of imparting hydrophilicity and the function of enhancing the affinity with the phospholipids contained in blood or urine to promote the action of the liquid film cracking agent.

Next, the manufacturing method of the long-fiber nonwoven fabric of the present invention will be described.

First of all, the basic long-fiber non-woven fabric manufacturing method can adopt the method used for such articles without special restrictions. For example, spunbonded non-woven fabrics are manufactured through the following steps: (1) the step of melt-spinning the raw resin and accumulating the long fibers on the conveyor; (2) hot embossing the obtained long fiber web (using Embossing convex rollers and flat rollers, etc.) to form the heat fusion part. Furthermore, the heat fusion part can be formed by various methods such as ultrasonic fusion, or intermittent application of hot air to perform partial fusion, other than thermal embossing.

In this manufacturing step, as a method of containing the above-mentioned liquid film cracking agent or the liquid film cracking agent and phosphate type anionic surfactant, or the above-mentioned hydrophilizing agent, examples include: (A) coating on non-woven fabric The latter method of raw material long-fiber non-woven fabric, (B) the method of coating on the surface of the fiber before non-woven fabric, (C) the method of adding to the resin that becomes the raw material of the fiber, etc. At this time, it can be applied in the form of a fiber treatment agent, which is a mixture of the above-mentioned liquid film cracking agent or the liquid film cracking agent and phosphate type anionic surfactant and the above-mentioned hydrophilizing agent. It is obtained by dilution, and can also be separately coated in the form of different fiber treatment agents. As the coating method of the fiber treatment agent, for example, coating by spray, coating by a slit coater, coating by a gravure method, a soft plate method, and a dipping method, etc. may be mentioned.

The liquid film cracking agent, or the liquid film cracking agent and the phosphate type anionic surfactant can be contained in the fiber in any step. For example, in the step (B) or (C) above, a liquid film cracking agent or a liquid film cracking agent and The mixture of phosphoric acid type anionic surfactants can be coated; it can also be coated after the non-woven fabric of (A) above; it can also be mixed with a liquid film cracking agent or liquid in the fiber finishing oil before and after the fiber is stretched. A mixture of a film cracking agent and a phosphoric acid type anionic surfactant is applied. In addition, a liquid film cracking agent or an anionic surfactant of the phosphate ester type can be formulated in a fiber treatment agent generally used in the manufacture of non-woven fabrics and coated on the fibers, or it can be coated after non-woven fabrics.

On the other hand, regarding the hydrophilizing agent, in order to impart a hydrophilicity gradient to the long-fiber nonwoven fabric, at least two different hydrophilizing agents must be applied separately. When the method of (A) above contains a hydrophilizing agent, the raw long fiber nonwoven fabric tends to be thinner than the nonwoven fabric using other short fibers as the raw material, so the hydrophilizing agent easily oozes out and it is difficult to dispense. In addition, when the method (B) or (C) above contains a hydrophilizing agent, it is difficult to continuously process the non-woven fabric from the long fiber to the non-woven fabric by thermal fusion in the same production line. Before non-woven fabrics, each fiber is separately coated with different hydrophilizing agents, or it is difficult to laminate fibers containing different hydrophilizing agents with each other before non-woven fabrics. Therefore, the following method can be adopted: a plurality of raw material long-fiber non-woven fabrics containing different hydrophilizing agents are layered on each other to form the long-fiber non-woven fabric of the present invention including multiple layers. That is, a method of forming the long-fiber non-woven fabric of multiple layers in Fig. 1(C) can be cited. In addition, even if it is a single layer, a method of changing the degree of hydrophilicity in the thickness direction by using the hydrophilizing agent combined with the heat generated by the hot air treatment can be adopted.

Or, even if it is a single layer, in the long-fiber nonwoven fabric 20 of FIG. 1(B), the vertical fiber 4 is formed by the stretching process, so that the hydrophilicity of the vertical fiber 4 becomes lower than that of the fiber assembly layer. 3 the hydrophilicity of the fiber. Thereby, the hydrophilicity of the upright fibers 4 on the side of the first surface 5 is lower than the hydrophilicity of the fibers of the fiber assembly layer 3 on the side of the second surface 6. In the thickness direction, there is a layer direction of the upright fibers 4 The two-stage hydrophilicity gradient of the rise of the fiber assembly layer 3. The reason is that when the raw long-fiber nonwoven fabric coated with a hydrophilizing agent is subjected to the following raising process, it becomes erect fiber 4 Compared with the fibers of the fiber assembly layer 3, the long fibers are stretched and broken. It is believed that the reason is that the hydrophilizing agent will also follow along with the elongation of the fiber, and with this, the concentration of the hydrophilizing agent in the part where the fiber is extended becomes thinner. On the contrary, when the followability of the hydrophilizing agent to the stretched fiber is low, it is considered that a part of the hydrophilizing agent is broken due to the extension of the fiber, and a part where the oil agent is present and a part where there is no oil agent are produced on the fiber. , Without generating a gradient of hydrophilicity (wetting on an uneven surface depends on the area ratio of each hydrophilizing agent component).

(Raising processing)

Fig. 4(A)~(D) show a method of manufacturing the long-fiber non-woven fabric 20 of Fig. 1(B) by forming the upright fibers 4 with free ends 42 from the raw material long-fiber non-woven fabric 200 coated with a hydrophilizing agent . Specifically, it can be a manufacturing method that only includes the raising process shown in Figure 4(C), or it can include the partial extension processing (pre-processing) and the drawing shown in Figure 4(A) and (B) in sequence. 4(C) shows the manufacturing method of the two-stage raising process of raising process. In order to obtain a long-fiber non-woven fabric with good skin feel and softness, a two-stage raising process is preferred.

In the two-stage raising process, the partial extension process shown in Figure 4 (A) and (B) is performed. Specifically, for the raw long-fiber nonwoven fabric 200 coated with a hydrophilizing agent, the raw long-fiber nonwoven fabric 200 is pinched by the meshing of the concave and convex rollers 74 and 75. In this way, local stretch processing is performed on a plurality of locations of the raw material long-fiber nonwoven fabric 200 and damages are caused. Then, in the breaking process shown in FIG. 4(C), the raw long-fiber nonwoven fabric 200 that has been locally stretched is conveyed by the conveying rollers 76 and 76 and an angle with respect to the raising roller 77 is given. The raising roller 77 has protrusions 79 for raising. Due to the rolling of the raising roller 77, a part of the long fibers on the surface of one side of the raw long-fiber non-woven fabric 200 that has been locally stretched is broken and raised to become erect fibers 4. In the above-mentioned raising treatment, the erect fibers 4 are more extended than the fibers constituting the unfluffed matrix part, that is, the fiber assembly layer 3. By extending in the above manner, the erection of the fiber The hydrophilicity of dimension 4 becomes lower than the hydrophilicity of the fibers constituting the fiber assembly layer 3.

Furthermore, the raising roller 77 may roll in either the opposite direction or the forward direction with respect to the conveying direction of the partially stretched raw long-fiber nonwoven fabric 200, but from the viewpoint of efficiently forming the standing fibers 4 In other words, it is preferable to scroll in the opposite direction.

In the long-fiber nonwoven fabric 20, the number of raised fibers is preferably 8 fibers/cm or more, and more preferably 12 fibers/cm from the viewpoint of improving cushioning properties and the viewpoint that the skin feels better when in contact with the skin. cm or more, more preferably 15 pieces/cm or more. The raised fiber here includes the upright fiber 4 having the free end 42 and the loop fiber. Also, from the viewpoint of ensuring sufficient breaking strength, it is preferably 100 pieces/cm or less, and from the viewpoint of preventing the appearance of fluffing and invisible, it is more preferably 40 pieces/cm or less, and more preferably 30 pieces/cm. Root/cm or less. In addition, the above-mentioned fluffed fiber was measured by the following measurement method. In this case, the term "long-fiber non-woven fabric with raised fibers" refers to the long-fiber non-woven fabric with raised fibers of 5 fibers/cm or more in the following measurement method.

(Determination of the number of fluffy fibers)

5(A) to (C) are schematic diagrams showing a method of measuring the number of fluffed fibers in the fibers constituting the long-fiber nonwoven fabric 20 under an environment of 22° C. and 65% RH. First, use a sharp razor to cut a 20cm×20cm measurement piece from the long-fiber nonwoven fabric 20 for measurement. As shown in FIG. 5(A), the raised surface of the measurement piece is convexly folded to form a measurement sample 104. Then, the measurement sample 104 was placed on an A4 size black backing paper, as shown in FIG. 5(B), and then an A4 size black backing paper having a hole 107 of 1 cm in length×1 cm in width was placed thereon. At this time, as shown in FIG. 5(B), the fold 105 of the measurement sample 104 is arranged so as to be visible from the hole 107 of the black backing paper on the upper side. The two backing papers use Fuji Kyowa Paper Co., Ltd. "KENRAN (black) continuous weight 265g". After that, follow the fold 105 on both sides of the hole 107 of the backing paper from the upper side. A weight of 50 g was placed on a position 5 cm away from the outside, and the measurement sample 104 was made in a fully folded state. Then, as shown in Fig. 5(C), using a microscope (VHX-900 manufactured by KEYENCE Co., Ltd.), the inside of the hole 107 of the backing paper was observed at a magnification of 30 times, and the amount existing above the imaginary line 108 was measured. The number of fibers per 1 cm. The imaginary line 108 is formed at a position where the measurement sample 104 moves in parallel 0.2 mm upward from the crease 105. Measure 9 locations, and set the average value (rounded to the second decimal place) as the number of fluffed fibers.

In addition, when counting the number of fluffed fibers, for example, when there is a fiber 106a shown in FIG. 5(C) that crosses the imaginary line 108 that is 0.2 mm upward from the crease 105 twice. , The count of the fiber line is 2. Specifically, in the example shown in FIG. 5(C), there are 4 fibers that traverse the imaginary line 108 once, and there are 1 fiber 106a that traverses the imaginary line 108 twice, but it traverses twice. The number of the fiber 106a is 2 and the number of the fluffy fiber is 6.

From the viewpoint of improving the touch of the skin when in contact with the skin, the long-fiber nonwoven fabric 20 is preferably a raised fiber (a fiber that crosses the imaginary thread 108. Here, as described above, it includes an upright having a free end 42 The average fiber diameter of both the sexual fiber 4 and the loop fiber is smaller than the surface fiber of the unfluffed part of the same surface (the fiber that does not cross the imaginary line 108 and does not reach the imaginary line 108, that is, the fiber assembly 3 is not The average fiber diameter of the raised fiber). The average fiber diameter refers to the fiber diameter obtained by measuring the fiber diameter at 12 locations of the fluffed fiber and the unfluffed fiber using a microscope (optical microscope, or scanning electron microscope, etc.). The average fiber diameter of the fluffed fibers is preferably 98% or less and 40% or more of the average fiber diameter of the unfluffed fibers, and if it is 96% or less and 70% or more, the skin feel is excellent, which is more preferable. Similarly, the average fiber diameter of the erect fibers 4 with the free end 42 and the average fiber diameter of the loop fibers are preferably smaller than the average fiber diameter of the fibers (non-raised fibers) constituting the fiber assembly 3, preferably Fibers that are unfluffed fibers The diameter is 98% or less and 40% or more, and if it is 96% or less and 70% or more, the skin feels excellent, so it is better.

Furthermore, it is preferable that the erect fiber 4 becomes thicker at the part of the free end 42. As the shape of the thickened shape, it is preferable that the cross section of the free end 42 is flat (elliptical or collapsed shape). Thereby, the upright fiber 4 with a soft tip is obtained, and the long-fiber non-woven fabric 20 with less irritation to the skin is obtained.

In addition, the long-fiber non-woven fabric 20 is preferably as described above, and the number of fluffed fibers (including the upright fibers 4 with free ends 42 and the fibers of the loop fibers) is 8 fibers/cm or more, and the fluffing of the fluffed fibers The height is 1.5mm or less. Thereby, an absorbent article with improved cushioning properties and improved skin touch is obtained. From the viewpoint of difficulty in pilling and depilation, it is more preferable that the raised height of the raised fibers is 1 mm or less. On the other hand, if it is 0.2mm or more, a good skin touch will be obtained. Furthermore, in terms of reducing the amount of liquid return in the absorption characteristics of body fluids, the fuzz height is preferably 0.5 mm or more. In the case of using a raised surface on the side in contact with the skin, the raised height is further preferably 1 mm or less in terms of being less likely to adhere to the skin and having a better touch. In addition, the case where the number of raised fibers is 15 fibers/cm or more is better in terms of improving cushioning properties and faster absorption of body fluids. In addition, in order to prevent the appearance of fluff-like appearance, or pilling or depilation due to friction during use, the height of the fluffed fiber is preferably 5 mm or less.

Here, the so-called fuzz height is different from the length of the fiber, which means the height of the fiber in the natural state without drawing the fiber during the measurement. If the length of the fluffed fiber is larger or the rigidity of the fiber is higher, the fluffing height of the fluffed fiber tends to become higher. The raising height of the raised fiber is measured by the following measuring method.

(Measuring method of raising height of raised fiber)

The raising height of the raised fiber is measured at the same time when the number of raised fibers (including the upright fibers 4 with the free ends 42 and the fibers of the loop fibers) is measured. Specific and In other words, as shown in FIG. 5(C), observe the inside of the hole 107 of the backing paper, and draw lines in parallel every 0.05 mm from the crease 105 until the fluffed fibers no longer intersect. Then, compared with the number of fluffed fibers measured in the above method (judged based on the imaginary line 108 above 0.2mm), choose the fiber that intersects with the parallel line to be half of the parallel line, and it will go from here to The distance between the creases is set as the raising height. Through the above operation, measure the 3 pieces of non-woven fabric for measurement, and take the average value of 3 pieces of 9 locations in each piece with 3 locations, and set it as the raised height of the raised fiber.

In addition to the raised height of the raised fibers and the number of raised fibers, in terms of obtaining softness when in contact with the skin and excellent skin touch, it is preferable that the overall flexibility of the long-fiber non-woven fabric 20 is 8cN or less . In terms of becoming a softer such as a swaddle for babies or infants, the overall flexibility of the long-fiber non-woven fabric 20 is more preferably 0.5 cN or more and 3 cN or less. The overall flexibility is measured by the following measuring method.

(Measurement method of overall flexibility)

Regarding the overall flexibility of the long-fiber non-woven fabric 20, cut the long-fiber non-woven fabric 20 by 150 mm in the MD direction and 30 mm in the CD direction, and use a stapler to fix the ends at the upper and lower positions to make the diameter 45mm ring. At this time, the core system of the fiber cutter (stapler) is set to become longer in the MD direction. Using a tensile testing machine (for example, Tensilon Tensilon Tensile Testing Machine "RTA-100" manufactured by Orientec Co., Ltd.), the above-mentioned ring is erected on the sample table in a cylindrical shape, and a flat plate approximately parallel to the sample table is used from above Compress at a compression speed of 10mm/min, measure the maximum load at this time, and set it as the overall flexibility in the CD direction. Then, the MD direction and the CD direction were changed to make a ring, and the overall flexibility in the MD direction was measured in the same way. The MD direction and the CD direction each produced two loops and measured them, and the average value of the CD direction and the MD direction was used as the overall flexibility of the long-fiber nonwoven fabric 20.

Furthermore, the so-called MD direction refers to the machine direction (MD: Machine Direction) in the manufacturing stage of the non-woven fabric, and refers to the length direction of the non-woven fabric being manufactured. When the non-woven fabric is used as a raw material sheet and made into a roll shape, or when the non-woven fabric is rolled out from the state of a roll, it means the direction in which the non-woven fabric is rolled out. On the other hand, the so-called CD direction means the width direction (CD: Cross Direction) orthogonal to the mechanical unloading direction in the manufacturing stage of the nonwoven fabric, and means the width direction orthogonal to the above-mentioned longitudinal direction in the manufactured nonwoven fabric. In the state of the above-mentioned raw material sheet, it means the direction of the roll axis. Furthermore, when the non-woven fabric is cut to a specific size and used as the front sheet of the absorbent article, the MD direction is the direction that coincides with the longitudinal direction of the absorbent article, and the CD direction is the same as the width direction of the absorbent article direction.

The long-fiber non-woven fabric of the present invention has high liquid permeability regardless of the thickness of the fibers or the distance between the fibers. However, the long-fiber nonwoven fabric of the present invention is particularly effective when using finer fibers. If thinner fibers are used to make long-fiber nonwoven fabrics that are softer to the skin than usual, the distance between the fibers will decrease and the narrow areas between the fibers will increase. In contrast, even if the fineness of the long-fiber nonwoven fabric of the present invention is lower than before, the liquid film cracking agent can surely crack the frequent liquid film and reduce liquid residue. As described below, the liquid film area ratio is the liquid film area ratio calculated by image analysis derived from the surface of the long-fiber nonwoven fabric, and is closely related to the liquid remaining state on the outermost surface of the surface material. Therefore, if the area ratio of the liquid film decreases, the liquid in the vicinity of the skin is removed, and the comfort after excretion is improved, making it an absorbent article with a good wearing feeling even after excretion.

On the other hand, the following liquid residual amount means the liquid amount retained by the entire long-fiber nonwoven fabric. If the area ratio of the liquid membrane becomes smaller, the liquid membrane will be cracked and unstable liquid will increase. Due to the gradient of hydrophilicity, the liquid will be drawn unidirectionally from the fiber layer with lower hydrophilicity to the fiber layer with higher hydrophilicity. As a result, liquid residue is reduced. Also, with regard to the whiteness of the surface, there is liquid due to the breakage of the liquid film on the surface The residual amount decreases and the whiteness tends to increase, so that the whiteness becomes visually conspicuous. The long-fiber non-woven fabric containing the liquid film cracking agent of the present invention can reduce the area ratio of the liquid film and the amount of residual liquid and whiten the surface even if the fibers are thinned. Therefore, it can achieve a high level of dryness and thinning of the fibers. And it gives the skin a soft touch. In addition, by using the long-fiber nonwoven fabric of the present invention as the surface material of an absorbent article and other structural members, it is possible to provide an absorbent article that has a high dry feeling due to the part in contact with the skin and is visually affected. White and the pollution caused by body fluids is not easy to be noticeable, so it achieves a comfortable feeling of peace of mind and good wearing feeling.

Regarding the long-fiber non-woven fabric containing a liquid film cracking agent and having a hydrophilicity gradient, from the viewpoint of improving the softness of the skin touch, the inter-fiber distance of the long-fiber non-woven fabric is preferably 300 μm or less, more preferably 250 μm or less . In addition, the lower limit is preferably 30 μm or more, and more preferably 50 μm or more from the viewpoint of suppressing loss of liquid permeability due to excessive narrowing between fibers. Specifically, it is preferably 30 μm or more and 300 μm or less, and more preferably 50 μm or more and 250 μm or less.

In this case, the fineness of the above-mentioned fiber is preferably 3.3 dtex or less, more preferably 2.4 dtex or less. In addition, the lower limit is preferably 0.5 dtex or more, and more preferably 0.7 dtex or more. Specifically, it is preferably 0.5 dtex or more and 3.3 dtex or less, and more preferably 0.7 dtex or more and 2.4 dtex or less.

(Method for measuring the distance between fibers)

The inter-fiber distance is determined by measuring the thickness of the long-fiber nonwoven fabric to be measured in the following manner, and inserting the following formula (2) into it.

First, the long-fiber nonwoven fabric to be measured is cut into 50 mm in the length direction×50 mm in the width direction to produce a cut sheet of the long-fiber nonwoven fabric. When the non-woven fabric of the measurement object is incorporated into absorbent articles such as sanitary products or disposable diapers, etc., the cut sheet of this size is not obtained In this case, cut to the maximum size obtained to make a cut sheet.

The thickness of the cut sheet was measured under a pressure of 49 Pa. The temperature of the measurement environment is 20±2°C, the relative humidity is 65±5%, and the measurement device uses a microscope (manufactured by KEYENCE Co., Ltd., VHX-1000). First, an enlarged photograph of the cross-section of the long-fiber nonwoven fabric is obtained. In the enlarged photo, the known size is displayed at the same time. The thickness of the long-fiber non-woven fabric was measured by comparing the enlarged photograph of the cross-section of the non-woven fabric with the scale. Perform the above operation 3 times, and set the average value of the 3 times as the thickness [mm] of the long-fiber non-woven fabric in the dry state. Furthermore, in the case of laminated products, the thickness is calculated by identifying the boundary based on the fiber diameter.

Then, the fiber-to-fiber distance of the long-fiber nonwoven fabric constituting the measurement object is calculated by the following equation based on Wrotnowski's assumption. The formula based on Wrotnowski's assumption is usually used when calculating the inter-fiber distance of the fibers constituting the non-woven fabric. According to the formula based on Wrotnowski's assumption, the distance A (μm) between fibers is based on the thickness h (mm) of the long-fiber non-woven fabric, the basis weight (weight per unit area) e (g/m ² ), and the fibers constituting the long-fiber non-woven fabric The diameter d (μm) and the fiber density ρ (g/cm ³ ) are calculated by the following equation (2). In addition, in the case of unevenness, the long-fiber nonwoven fabric thickness h (mm) of the protrusions is used as a representative value for calculation.

The fiber diameter d (μm) was measured using a scanning electron microscope (DSC6200 manufactured by Seiko Instruments Co., Ltd.), and the fiber cross section of 10 cut fibers was measured, and the average value was taken as the fiber diameter.

The fiber density ρ (g/cm ³ ) is measured using a density gradient tube and measured in accordance with the measurement method of the density gradient tube method described in JIS L1015 Chemical Fiber Short Fiber Test Method.

The basis weight e (g/m ² ) is to cut the long-fiber nonwoven fabric of the measuring object into specific (0.12m×0.06m, etc.) dimensions. After the mass measurement, use "mass÷area calculated from specific dimensions = basis Weight (g/m ² )" formula is calculated to obtain the basis weight.

(Measurement method of fiber size)

The cross-sectional area of the fiber is measured by measuring the cross-sectional shape of the fiber with an electron microscope or the like (if it is a fiber formed of multiple resins, the cross-sectional area of each resin component), and the other is by DSC (differential scanning calorimetry, differential thermal analysis) Device) Specify the type of resin (in the case of multiple resins, the approximate composition ratio is also specified), and calculate the specific gravity to calculate the fineness. For example, if it is a short fiber composed only of PET (polyethylene terephthalate, polyethylene terephthalate), first observe the cross section and calculate the cross-sectional area. After that, by measuring with DSC, it was identified from the melting point or peak shape that it was composed of a single-component resin and that it was a PET core. Thereafter, the density and cross-sectional area of the PET resin are used to calculate the fiber mass, thereby calculating the fineness.

The fibers constituting the long-fiber nonwoven fabric of the present invention mainly contain thermally fusible fibers, and such articles can be used without particular limitation. Examples of heat-fusible fibers include polyolefin resins, polyester resins, polyamide resins, acrylonitrile resins, vinyl resins, and vinylidene resins. As polyolefin resin, polyethylene, polypropylene, polybutene, etc. are mentioned. As polyester resin, polyethylene terephthalate, polybutylene terephthalate, etc. are mentioned. Examples of polyamide resins include nylon. Examples of vinyl resins include polyvinyl chloride and the like. Examples of the vinylidene resin include polyvinylidene chloride and the like. Various resins such as these can be used alone or in combination of two or more, and modified products of various resins such as these can also be used. In addition, composite fibers can also be used as long fibers. As the composite fiber, side-by-side fibers, core-sheath fibers, eccentric crimped core-sheath fibers, split fibers, etc. can be used. When using composite fibers, if the core contains polypropylene and the sheath contains polyethylene The core-sheath fiber is better in terms of obtaining a soft long-fiber non-woven fabric. Regarding the fiber diameter of the long fiber, before the following processing, it is preferably 5 μm or more and 30 μm or less, and more preferably 10 μm or more and 20 μm or less.

From the viewpoint of spinnability, it is preferably formed of polypropylene resin which is a polyolefin resin. As the polypropylene resin, it is preferable to include any one or more of random copolymers, homopolymers, and block copolymers from the viewpoint of improving the touch of the skin when it comes into contact with the skin and the viewpoint of ease of breaking. 5 mass% or more and 100 mass% or less, more preferably 25 mass% or more and 80 mass% or less resin. In addition, copolymers or homopolymers such as these can be mixed, and other resins can also be mixed. However, in terms of the fact that it is not easy to break during molding, polypropylene homopolymers and random copolymers are preferred.之mix. By this, the crystallinity of the fiber is reduced, and the fluffed fiber itself becomes soft, and the skin feels better when it comes into contact with the skin, and it can be compatible with the breaking strength of the non-woven fabric, and the fluffed fiber is easy to be trapped in the fusion part such as embossing. Cut off. Therefore, the peeling of the heat fusion part 3 obtained at the embossed fusion point, etc. will not occur, the fluffed fibers will be shortened, pilling will not be easy, and the appearance will be good. In addition, since the distribution of the melting point becomes wider, the sealing performance becomes better. More preferably, it is obtained by copolymerizing a propylene component as a matrix with ethylene or an α-olefin which is a random copolymer, and particularly preferably an ethylene propylene copolymer resin. As the polypropylene resin, from the same viewpoint, a resin containing 5% by mass or more of the ethylene propylene copolymer resin is preferable, and a resin containing 25% by mass or more of the ethylene propylene copolymer resin is more preferable. In the ethylene propylene copolymer resin, it is preferable to include one with an ethylene concentration of 1% by mass or more and 20% by mass or less, especially in terms of non-sticky feeling, easy extension during stretching, less hair removal, and maintenance of breaking strength. More preferably, the ethylene concentration is 3% or more and 8% or less. In addition, as the polypropylene resin, from an environmental point of view, a resin containing 50% by mass or more of recycled polypropylene resin is preferable, and a resin containing 70% by mass or more of recycled polypropylene resin is more preferable. Furthermore, for long fibers based on multiple layers of spunbond layer and meltblown layer The same is true when forming a non-woven fabric without woven fabric.

The basis weight (weight per unit area) of the long-fiber nonwoven fabric of the present invention is preferably 10 g/m ² or more and 80 g/m ² or less, particularly 15 g/m ² or more and 60 g/m ² or less. Furthermore, when the long-fiber non-woven fabric of the present invention includes a plurality of layers, it is preferable that the total basis weight (weight per unit area) of each layer is within the above-mentioned preferable numerical range.

Since the long-fiber nonwoven fabric of the present invention has a hydrophilicity gradient and contains a liquid film cracking agent or an anionic surfactant of the phosphate ester type therein, it can cope with various fiber structures and is excellent in the suppression of liquid residue and liquid return. Therefore, even if the long-fiber non-woven fabric is sprayed with a large amount of liquid, the passage of liquid between the fibers is always ensured, and the liquid permeability is excellent. Thereby, it is not limited by the distance between fibers and the formation of liquid film, and various functions can be imparted to the long-fiber non-woven fabric. For example, it may include a plurality of layers of 3 or more layers. In addition, the shape of the long-fiber non-woven fabric can be flat, one or both sides can be provided with unevenness, and the basis weight or density of the fiber can be changed in various ways. Furthermore, the range of options for the combination with the absorber is also expanded. In addition, the liquid film cracking agent in the case of including a plurality of layers may be contained in all the layers, or may be contained in a part of the layers. It is preferably contained at least in the layer on the side directly receiving the liquid. For example, when the long-fiber nonwoven fabric of the present invention is used as a top sheet of an absorbent article, it is preferable to contain a liquid film cracking agent at least in the layer on the skin contact surface side.

The long-fiber nonwoven fabric of the present invention preferably has a liquid film cracking agent locally present near at least a part of the fiber entanglement point or near the fiber fusion point. The "local presence" of the liquid film cracking agent here is not a state where the liquid film cracking agent is evenly attached to the entire surface of the fibers constituting the long-fiber nonwoven fabric, but refers to the state in which the liquid film is compared to the surface of each fiber The cracking agent tends to adhere to the vicinity of the fiber entanglement point or the fiber fusion point. Specifically, it can be defined as: Compared with the fiber surface (the fiber surface between the entanglement points or the fusion point), the liquid film cracking agent near the fusion point or the fusion point is concentrated Degree is higher. At this time, the liquid film cracking agent existing near the fiber entanglement point or near the fiber fusion point can also be attached in a manner such that the fiber entanglement point or the fiber fusion point is the center and the space between the fibers is partially covered. The concentration of the liquid film cracking agent near the intersection or fusion point is the more concentrated the better. The concentration varies according to the type of liquid film cracking agent used, the type of fiber used, the ratio of effective ingredients when mixed with other agents, etc., so it cannot be determined uniformly, but the above-mentioned liquid film is used. From the viewpoint of cracking effect, it can be appropriately determined.

Since the liquid film cracking agent is locally present, it becomes easier to exhibit the liquid film cracking effect. That is, the vicinity of the fiber entanglement point or the fiber fusion point is a position where the liquid film is particularly likely to be generated. Therefore, by allowing more liquid film cracking agent to exist in this position, it becomes easy to directly act on the liquid film.

As mentioned above, the local presence of the liquid film cracking agent is preferably generated by more than 30% near the fiber entanglement point or near the fiber fusion point of the entire long-fiber nonwoven fabric, more preferably generated by more than 40%, and more preferably generated by 50%. Produced above %. In the long-fiber non-woven fabric, when the distance between the fiber entanglement point or the fiber fusion point is relatively short, the space between the fibers is small and liquid film is particularly prone to occur. Therefore, if the liquid film cracking agent is selectively and locally present near the fiber entanglement point or near the fiber fusion point when the space between the fibers is small, the liquid film cracking effect is particularly effective, which is preferable. In addition, in the case of selective local presence as described above, the liquid film cracking agent is preferably to increase the coverage rate of the relatively small inter-fiber space and increase the coverage rate of the relatively large inter-fiber space Become smaller. Thereby, while maintaining the liquid permeability in the long-fiber non-woven fabric, it can effectively express the cracking effect of the part where the capillary force is large and the liquid film is easy to be generated, so that the liquid residue reduction effect of the whole long-fiber non-woven fabric becomes higher. The "relatively small inter-fiber space" herein refers to an inter-fiber space having an inter-fiber distance of 1/2 or less with respect to the inter-fiber distance obtained by the above-mentioned (Method for Measuring Inter-fiber Distance).

(Method to confirm the local existence of liquid film cracking agent)

The local existence state of the above-mentioned liquid film cracking agent can be confirmed by the following method.

First, cut the long-fiber non-woven fabric into 5mm×5mm, and install it on the sample table using carbon tape. The sample stage was placed in a scanning electron microscope (S4300SE/N, manufactured by Hitachi, Ltd.) without vapor deposition, and set to a low vacuum or vacuum state. Because the ring-shaped reflective electron detector (accessory) is used for detection, the larger the atomic number, the easier it is to release the reflected electrons. Therefore, the coating contains more atomic number than the main constituent polyethylene (PE) or polypropylene (PP) Or the part of the liquid film cracking agent of polyester (PET) carbon atom, hydrogen atom, oxygen atom or silicon atom appears whitish, so the localized state can be confirmed by the whitishness. Furthermore, with regard to its whiteness, the greater the atomic number or the greater the amount of adhesion, the more the whiteness will increase.

In the manufacturing method of the long-fiber nonwoven fabric of the present invention, when the liquid film cracking agent is applied after non-woven fabric as described above, a method of immersing the raw non-woven fabric in a solution containing the liquid film cracking agent can be cited. Examples of the above-mentioned solution include a solution obtained by diluting a liquid film cracking agent with a solvent (hereinafter, this solution is also referred to as a liquid film cracking agent solution). Examples of the solvent for dilution include alcohols such as ethanol. Moreover, as another method, the method of applying a liquid film cracking agent alone or a solution containing the above-mentioned liquid film cracking agent to the raw nonwoven fabric can be cited. Furthermore, it is also possible to mix a phosphate type anionic surfactant in the solution containing the above-mentioned liquid film cracking agent. In this case, the content ratio of the liquid film cracking agent to the phosphate type anionic surfactant is preferably as described above. As the above-mentioned solvent, a liquid film cracking agent with extremely low water solubility can be suitably dissolved or dispersed in a solvent and emulsified so that it can be easily applied to a non-woven fabric. For example, as a liquid film cracking agent, organic solvents such as ethanol, methanol, acetone, hexane can be used, or when it is made into an emulsified liquid, of course, water can also be used as a solvent or dispersion medium for emulsification. The emulsifiers used include: alkyl phosphates, fatty amides, alkyl betaines, alkyl sulfosuccinates Various surfactants such as sodium peroxylate. In addition, the so-called raw material nonwoven fabric refers to the one before the coating liquid film cracking agent, and as the production method thereof, the production method generally used as described above can be used without particular limitation.

As a method of coating the above-mentioned raw non-woven fabric, a manufacturing method that can be used for the non-woven fabric can be used without particular limitation. Examples include: spray coating, slit coater coating, gravure method, soft plate method, dipping method, and the like.

From the viewpoint that the liquid film cracking agent is locally present near the fiber entanglement point or fiber fusion point mentioned above, it is preferably applied to the raw non-woven fabric after non-woven fabricization, and more preferably applied to the raw non-woven fabric without impregnation. method. Among the coating methods, from the viewpoint of making the localization of the liquid film cracking agent more obvious, the coating method using a flexographic method is particularly preferred.

In addition, as the raw material non-woven fabric, various non-woven fabrics can be used without particular limitation. Especially from the viewpoint of maintaining the local presence of the liquid film cracking agent, it is preferable to heat fusion or thermocompression at the fiber intersection points, and it is more preferable to use the above-mentioned hot air treatment or hot embossing to connect the fibers to each other. Non-woven fabric obtained by thermal bonding.

When the liquid film cracking agent is attached to the fibers, it is preferably used in the form of a fiber treatment agent containing the liquid film cracking agent. The so-called "fiber treatment agent" described here refers to the following, that is, the use of water and surfactants to emulsify an oily liquid film cracking agent with extremely low water solubility, etc., to make it easy to coat the raw non-woven fabric or fiber The state of processing. In the fiber treatment agent used for coating the liquid film cracking agent, the content of the liquid film cracking agent is preferably 50% by mass or less with respect to the mass of the fiber treatment agent. Thereby, the fiber treatment agent can be in a state where the liquid film cracking agent, which becomes an oily component, is stably emulsified in the solvent. From the viewpoint of stable emulsification, the content ratio of the liquid film cracking agent is more preferably 40% by mass or less, and more preferably 30% by mass or less relative to the mass of the fiber treatment agent. In addition, it is realized that the liquid film cracking agent moves on the fiber at a moderate viscosity after coating. From the viewpoint of localization of the liquid film cracking agent in the non-woven fabric described above, it is preferable to set the content ratio described above. Regarding the content ratio of the liquid film cracking agent, from the viewpoint of exhibiting a sufficient liquid film cracking effect, it is preferably 5% by mass or more relative to the mass of the fiber treatment agent, more preferably 15% by mass or more, and still more preferable It is 25% by mass or more. Furthermore, the fiber treatment agent containing the liquid film cracking agent may also contain other agents within a range that does not inhibit the action of the liquid film cracking agent. For example, the above-mentioned phosphate type anionic surfactant may also be contained. In this case, the content ratio of the liquid film cracking agent to the phosphate type anionic surfactant is preferably as described above. In addition, it may also contain antistatic agents or friction-resistant agents used in fiber processing, hydrophilizing agents that impart moderate hydrophilicity to long fiber non-woven fabrics, and emulsifiers that impart emulsification stability.

The long-fiber non-woven fabric of the present invention can effectively utilize its soft skin touch and the reduction of liquid residue to be applied in various fields. For example, it can be preferably used as the front sheet and the second sheet (arranged on the front) of absorbent articles used for absorbing liquid discharged from the body such as menstrual tampons, sanitary pads, disposable diapers, incontinence pads, etc. The sheet between the sheet and the absorber), back sheet, leak-proof sheet, or wiping sheet for human use, sheet for skin care, and wipe cloth for objective lens, etc. When the long-fiber nonwoven fabric of the present invention is used as the front sheet or the second sheet of an absorbent article, it is preferable to use the first layer side of the long-fiber nonwoven fabric as the skin facing side.

The absorbent article used for absorbing the liquid discharged from the body typically has a front sheet, a back sheet, and a liquid-retaining absorbent interposed between the two sheets. As the absorbent body and the back sheet when the long-fiber nonwoven fabric of the present invention is used as the front sheet, materials generally used in these technical fields can be used without particular limitation. For example, as the absorber, a fiber assembly containing fibrous materials such as pulp fibers is coated with a coating sheet such as toilet paper or nonwoven fabric, or an absorbent polymer is retained therein. As the back sheet, a liquid-impermeable or water-repellent sheet such as a film of a thermoplastic resin or a laminate of the film and a non-woven fabric can be used. The back sheet may also have water vapor permeability. The absorbent article may further have various members corresponding to the specific use of the absorbent article. The above-mentioned components are well known to the industry. For example, when the absorbent article is used in disposable diapers or menstrual napkins, one or more pairs of three-dimensional protections can be arranged on the left and right sides of the front sheet.

Regarding the above-mentioned embodiment, the present invention further discloses the following long-fiber nonwoven fabric.

<1>

A long-fiber non-woven fabric containing a liquid film cracking agent.

<2>

The long-fiber non-woven fabric as described in the above <1>, wherein the water solubility of the liquid film cracking agent is 0 g or more and 0.025 g or less.

<3>

The long-fiber non-woven fabric described in the above item <2>, wherein the spreading coefficient of the liquid film cracking agent to a liquid with a surface tension of 50 mN/m is 15 mN/m or more.

<4>

A long-fiber non-woven fabric containing a compound (C1) having a water solubility of 0 g or more and 0.025 g or less, and a spreading coefficient of 15 mN/m or more for a liquid with a surface tension of 50 mN/m.

<5>

The long-fiber nonwoven fabric according to any one of the above <1> to <4>, wherein the interfacial tension of the compound (C1) or the liquid film cracking agent to a liquid with a surface tension of 50 mN/m is 20 mN/m or less.

<6>

The long-fiber non-woven fabric as described in any one of the above <1> to <5>, wherein the above-mentioned compound The compound (C1) or the above-mentioned liquid film cracking agent includes a compound having at least one structure selected from the group consisting of the following structures X, X-Y, and Y-X-Y.

Structure X represents >C(A)-(C represents a carbon atom. In addition, <,> and-represent bonding bonds. The same applies below), -C(A) ₂ -, -C(A)(B)-, >C(A)-C(R ¹ )<, >C(R ¹ )-, -C(R ¹ )(R ² )-, -C(R ¹ ) ₂ -, >C< and, -Si( Any one of R ¹ ) ₂ O- or -Si(R ¹ )(R ² )O- has a repeating basic structure or a combination of two or more types of siloxane chains, or a mixed chain thereof. It has a hydrogen atom at the end of structure X, or is selected from -C(A) ₃ , -C(A) ₂ B, -C(A)(B) ₂ , -C(A) ₂ -C(R ¹ ) ₃ , -C(R ¹ ) ₂ A, -C(R ¹ ) ₃ , and -OSi(R ¹ ) ₃ , -OSi(R ¹ ) ₂ (R ² ), -Si(R ¹ ) ₃ , -Si( At least one group in the group consisting of R ¹ ) ₂ (R ^{2 ).}

The aforementioned R ¹ or R ² each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom. A and B each independently represent a substituent containing an oxygen atom or a nitrogen atom. ^{When there are a plurality of R 1} , R ² , A, and B in the structure X, they may be the same or different from each other.

Y represents a hydrophilic group containing an atom selected from a hydrogen atom, a carbon atom, an oxygen atom, a nitrogen atom, a phosphorus atom, and a sulfur atom. When Y is plural, they may be the same or different.

<7>

The long-fiber nonwoven fabric according to any one of the above <1> to <6>, wherein the compound (C1) or the liquid film cracking agent includes an organically modified polysiloxane of a polysiloxane-based surfactant, and is used as the Organically modified silicone, including selected from the group consisting of amine modified silicone, epoxy modified silicone, carboxyl modified silicone, glycol modified silicone, methanol modified silicone, (former Base) acrylic-based modified polysiloxane, mercapto-modified polysiloxane, phenol-modified polysiloxane, polyether-modified polysiloxane, methylstyrene-based modified polysiloxane, long-chain alkyl modified polysiloxane Silicone, higher fatty acid ester modified polysiloxane, higher alkoxy modified polysiloxane, higher fatty acid modified polysiloxane and fluorine modified polysiloxane At least one of them.

<8>

The long-fiber nonwoven fabric according to any one of the above <1> to <7>, wherein the compound (C1) or the liquid film cracking agent comprises a polyoxyalkylene-modified polysiloxane, and the polyoxyalkylene The modified silicone is at least one selected from the group consisting of compounds represented by the following formulas [I] to [IV].

In the formula, R ³¹ represents an alkyl group (preferably with a carbon number of 1-20. For example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, 2-ethyl are preferred. Hexyl, nonyl, decyl). R ³² represents a single bond or an alkylene group (preferably with a carbon number of 1 to 20. For example, methylene, ethylene, propylene, and butylene are preferred), and preferably represents the above-mentioned alkylene. The plurality of R ³¹ and the plurality of R ³² may be the same or different from each other. M ¹¹ represents a group having a polyoxyalkylene group, preferably a polyoxyalkylene group. Examples of the above-mentioned polyoxyalkylene group include polyoxyethylene group, polyoxypropylene group, polyoxybutylene group, and those obtained by copolymerizing constituent monomers such as these. m and n are each independently an integer of 1 or more. Furthermore, the symbols of the repeating units are determined separately in each of the formulas [I] to [IV], and may not necessarily represent the same integer, but may be different.

<9>

The long-fiber non-woven fabric described in the above item <2>, wherein the spreading coefficient of the liquid film cracking agent to a liquid with a surface tension of 50mN/m is greater than 0mN/m, and the interfacial tension to a liquid with a surface tension of 50mN/m is 20mN/ m or less.

<10>

A long-fiber non-woven fabric containing compound (C2), the compound (C2) has a water solubility of 0g or more and 0.025g or less, and has a spreading coefficient for liquids with a surface tension of 50mN/m greater than 0mN/m. The interfacial tension of a liquid of 50mN/m is less than 20mN/m.

<11>

The long-fiber non-woven fabric described in any one of the above <1>, <2>, <9> and <10>, wherein the above compound (C2) or the above liquid film cracking agent comprises a structure Z, A compound of at least one structure in the group consisting of ZY and YZY.

Structure Z means that >C(A)-(C: carbon atom), -C(A) ₂ -, -C(A)(B)-, >C(A)-C(R ³ )<, >C (R ³ )-, -C(R ³ )(R ⁴ )-, -C(R ³ ) ₂ -, >C< any one of the basic structure repeats, or a combination of two or more of the structure formed by the hydrocarbon chain . It has a hydrogen atom at the end of structure Z, or is selected from -C(A) ₃ , -C(A) ₂ B, -C(A)(B) ₂ , -C(A) ₂ -C(R ³ ) ₃ , -C(R ³ ) ₂ A, -C(R ³ ) ₃ at least one group in the group.

The aforementioned R ³ or R ⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a fluoroalkyl group, an aralkyl group, or a hydrocarbon group formed by combining them, or a fluorine atom. A and B each independently represent a substituent containing an oxygen atom or a nitrogen atom. ^{When there are a plurality of R 3} , R ⁴ , A, and B in the structure Z, they may be the same or different from each other.

Y represents a hydrophilic group containing an atom selected from a hydrogen atom, a carbon atom, an oxygen atom, a nitrogen atom, a phosphorus atom, and a sulfur atom. In the case of a plurality of Ys, they may be the same or different from each other.

<12>

The long-fiber nonwoven fabric described in any one of the above <1>, <2>, and <9>~<11>, wherein the above compound (C2) or the above liquid film cracking agent comprises any one selected from the following formula [V] Polyoxyalkylene (POA) alkyl ether represented by one, and polyoxyalkylene glycol with a mass average molecular weight of 1000 or more represented by the following formula [VI], stearyl alcohol polyether, and behenyl alcohol At least one compound in the group consisting of polyether, PPG myristyl ether, PPG stearyl ether and PPG behenyl ether.

In the formula, L ²¹ represents ether group, amino group, amide group, ester group, carbonyl group, carbonate group, polyoxyethylene group, polyoxyethylene group, polyoxyethylene group, or a combination thereof The polyoxyalkylene and other bonding groups. R ⁵¹ represents a hydrogen atom, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, decyl, methoxy, ethoxy , Phenyl, fluoroalkyl, aralkyl, or a combination of these and other hydrocarbon groups, or various substituents of fluorine atoms. In addition, a, b, m, and n are each independently an integer of 1 or more. Here, C _m H _n represents an alkyl group (n=2m+1), and C _a H _b represents an alkylene group (a=2b). Furthermore, the number of carbon atoms and the number of hydrogen atoms are determined independently in each of the formulas [V] and [VI], and they do not necessarily represent the same integer, and may be different. Furthermore, "m" of -(C _a H _b O) _m -is an integer of 1 or more. The value of the repeating unit is determined independently in each of the formulas [V] and [VI], and does not necessarily represent the same integer, but may be different.

<13>

The long-fiber nonwoven fabric as described in any one of the above <1>, <2>, and <9> to <12>, wherein the compound (C2) or the liquid film cracking agent is selected from those represented by the following formula [VII] Fatty acid, glycerol fatty acid ester and pentaerythritol fatty acid ester represented by the following formula [VIII-I] or [VIII-II], any one of the following formula [IX], any one of the following formula [X] Or partial ester products of glycerol fatty acid ester, sorbitan fatty acid ester, and pentaerythritol fatty acid ester represented by any one of the following formula [XI], and having a sterol structure of the following formula [XII] At least one of the compound, the alcohol represented by the following formula [XIII], the fatty acid ester represented by the following formula [XIV], and the wax represented by the following formula [XV].

[化25] C _m H _n -COOH [VII]

In formula [VII], m and n are each independently an integer of 1 or more. Here, C _m H _n represents the hydrocarbon group of each of the above-mentioned fatty acids.

In formulas [VIII-I] and [VIII-II], m, m', m", n, n', and n" are each independently an integer of 1 or more. The plural m and the plural n may be the same or different from each other. _{Here, C m H n, C m} 'H n' and C _m "H _n" each denote a hydrocarbon group of a fatty acid.

In formula [IX], m and n are each independently an integer of 1 or more. The plural m and the plural n may be the same or different from each other. Here, C _m H _n represents the hydrocarbon group of each of the above-mentioned fatty acids.

In formula [X], R ⁵² represents a linear or branched, saturated or unsaturated hydrocarbon group (alkyl, alkenyl, alkynyl, etc.) having 2 or more and 22 or less carbon atoms. Specifically, 2-ethylhexyl, lauryl, myristyl, palmityl, stearyl, behenyl, oleyl, linseed, etc. can be mentioned.

In formula [XI], m and n are each independently an integer of 1 or more. The plural m and the plural n may be the same or different from each other. Here, C _m H _n represents the hydrocarbon group of each of the above-mentioned fatty acids.

[化32] C _m H _n -OH [XIII]

In formula [XIII], m and n are each independently an integer of 1 or more. Here, C _m H _n represents the hydrocarbon group of each of the above-mentioned alcohols.

[化33] C _m H _n -COO-C _m H _n [XIV]

In formula [XIV], m and n are each independently an integer of 1 or more. Here, two C _m H _n may be the same or different. C _m H _n -COO- C _m H _n denotes the above-mentioned hydrocarbon group for each of the fatty acid. -COOC _m H _n C _m H _n represents the hydrocarbon group of the alcohol from the ester formed.

[化34] C _m H _n [XV]

In formula [XV], m and n are each independently an integer of 1 or more.

<14>

The long-fiber nonwoven fabric according to any one of the above <1> to <13>, wherein the water solubility of the above compound (C1), the above compound (C2) or the above liquid film cracking agent is preferably 0.0025 g or less, more preferably 0.0017 g or less, more preferably less than 0.0001 g, and 0 g or more, preferably 1.0×10 ^-9 g or more.

<15>

The long-fiber nonwoven fabric according to any one of the above <1> to <14>, wherein the compound or the liquid film cracking agent is locally present near at least a part of the long-fiber non-woven fabric near the fiber entanglement point or near the fiber fusion point.

<16>

The long-fiber nonwoven fabric as described in any one of the above <1> to <15>, which contains heat-fusible fibers, has a first surface and a second surface located on the opposite side of the first surface, and The hydrophilicity of the fibers on the first surface side is lower than the hydrophilicity of the fibers on the second surface side.

<17>

The long-fiber non-woven fabric according to any one of the above <1> to <16>, wherein the long-fiber non-woven fabric contains heat-fusible fibers and has a first surface and a second surface located on the opposite side of the first surface, and Equipped with a fiber assembly layer that intermittently fixes long fibers by a thermal fusion part.

<18>

The long-fiber non-woven fabric according to any one of the above <1> to <17>, wherein the long-fiber non-woven fabric contains heat-fusible fibers and has a first surface and a second surface located on the opposite side of the first surface, and The fiber length of the long fiber of the long-fiber non-woven fabric is 30 mm or more, preferably the fiber length is 150 mm or more.

<19>

The long-fiber non-woven fabric according to any one of the above <1> to <18>, wherein the long-fiber non-woven fabric contains heat-fusible fibers and has a first surface and a second surface located on the opposite side of the first surface, and The contact angle (V1) of the fibers on the first surface side is preferably 80° or more, more preferably 85° or more, still more preferably 90° or more, and preferably 100° or less, more preferably 97° or less, More preferably, it is 95° or less.

<20>

The long-fiber nonwoven fabric according to any one of the above <1> to <19>, wherein the long-fiber nonwoven fabric contains heat-fusible fibers and has a first surface and a second surface located on the opposite side of the first surface, and The contact angle (V2) of the fibers on the second surface side is preferably 90° or less, more preferably 85° or less, still more preferably 80° or less, and preferably 30° or more, more preferably 40° or more, More preferably, it is 50° or more.

<21>

The long-fiber non-woven fabric according to any one of the above <1> to <20>, wherein the long-fiber non-woven fabric contains heat-fusible fibers and has a first surface and a second surface located on the opposite side of the first surface, and The difference (V1-V2) between the contact angle (V1) of the fibers on the first surface side and the contact angle (V2) of the fibers on the second surface side (non-skin contact surface side) is preferably 3° or more, more It is preferably 5° or more, more preferably 7°, and particularly preferably 10°.

<22>

The long-fiber non-woven fabric according to any one of the above <1> to <21>, wherein the long-fiber non-woven fabric contains heat-fusible fibers and has a first surface and a second surface located on the opposite side of the first surface, and Contains hydrophilizing agent.

<23>

The long fiber nonwoven fabric according to any one of the above <1> to <22>, wherein the long fiber nonwoven fabric contains heat-fusible fibers and has a first surface and a second surface located on the opposite side of the first surface, and Contains at least one selected from the group consisting of anionic, cationic, amphoteric and nonionic surfactants.

<24>

The long-fiber non-woven fabric as described in any one of the above <1> to <23>, wherein the long-fiber non-woven fabric includes a single layer, contains heat-fusible fibers, and has a first surface and an opposite side of the first surface The second surface, and the hydrophilicity of the fibers on the first surface side is lower than the hydrophilicity of the fibers on the second surface side, and has a gradient of hydrophilicity.

<25>

The long-fiber non-woven fabric according to any one of the above <1> to <24>, wherein the long-fiber non-woven fabric contains heat-fusible fibers and has a first surface and a second surface located on the opposite side of the first surface, and The fiber on the first surface side has a base fixed to the fiber assembly layer and is not connected to the fiber. The free end of the dimensional assembly layer is fixed and the erect fiber is erected.

<26>

The long-fiber nonwoven fabric as described in the above <25>, which has at least a two-step hydrophilicity gradient in which the hydrophilicity of the erect fibers is lower than the hydrophilicity of the fibers of the fiber assembly layer.

<27>

The long-fiber nonwoven fabric as described in the above <26>, wherein the contact angle of the standing fibers is 75° or more, preferably 80° or more, more preferably 85° or more, and still more preferably 90° or more.

<28>

The long-fiber non-woven fabric as described in any one of the above <1> to <23>, wherein the long-fiber non-woven fabric includes a plurality of layers, contains heat-fusible fibers, and has a first surface and an opposite side of the first surface On the second surface, each of the above-mentioned plural layers has a difference in the degree of hydrophilicity, and the degree of hydrophilicity is gradually increased.

<29>

A front sheet for absorbent articles, which uses the long-fiber non-woven fabric described in any one of the above <1> to <28>.

<30>

An absorbent article using the long-fiber nonwoven fabric as described in any one of the above <14> to <28> as a front sheet with the first surface facing the skin contact surface side.

[Example]

Hereinafter, the present invention will be described in further detail based on examples, but the present invention should not be interpreted limitedly. In addition, in this embodiment, "parts" and "%" are all quality standards unless otherwise specified.

The surface tension, water solubility and interfacial tension of the liquid film cracking agent in the following examples are based on Carried out by the above-mentioned measuring method.

(Example 1)

As the raw material long-fiber non-woven fabric, a spun-bonded non-woven fabric (SS non-woven fabric) with two layers of spun-bonded non-woven fabric composed of long fibers containing polypropylene homopolymer resin is produced. The two layers (the first non-woven fabric layer and the second non-woven fabric layer) are both set to have a long fiber diameter of 16 μm and a basis weight of 10 g/m ² .

For the above-mentioned first non-woven fabric layer and second non-woven fabric layer, the following liquid film cracking agent and hydrophilizing agent are coated by the coating method shown below before lamination, by using the heat of the embossing roller The two layers were joined and fixed by crimping, and the long-fiber non-woven fabric sample of Example 1 was prepared. In this long-fiber nonwoven fabric sample, the two sides of the first nonwoven fabric layer are defined as the first surface side (a) and the second surface side (b), and the two surfaces of the second nonwoven fabric layer are defined as the first surface side (a' ) And the second surface side (b'), as the entire long-fiber nonwoven fabric sample, the two sides after the two layers are laminated are defined as the first surface 5 side (the first surface side of the first nonwoven fabric layer) (a) and the first Two surfaces and six sides (the second surface side of the second nonwoven fabric layer) (b') were tested (hereinafter, the same applies to Examples 2 to 4 and Comparative Examples 1 and 2).

<Liquid film cracking agent>

As a liquid film cracking agent, X in the structure XY contains _{dimethyl polysiloxane chain containing -Si(CH 3} ) ₂ O-, Y contains _{POE chain containing -(C 2} H ₄ O)-, POE chain The end group is methyl (CH ₃ ), the modification rate is 20%, the polyoxyethylene addition molar number is 3, and the polyoxyethylene (POE) modified dimethyl with a mass average molecular weight of 4000 Base polysiloxane (KF-6015 manufactured by Shin-Etsu Chemical Co., Ltd.).

Spread coefficient for liquid with a surface tension of 50mN/m: 28.8mN/m

The surface tension is 21.0mN/m

Interfacial tension to liquid with surface tension of 50mN/m: 0.2mN/m

Water solubility: less than 0.0001g

Furthermore, the four values are measured by the above-mentioned measuring method. At this time, the "liquid with a surface tension of 50mN/m" uses the following solution, which uses a micropipette (ACURA825, manufactured by Socorex Isba SA) to add polyoxyethylene as a nonionic interfacial active substance to 100g of deionized water Sorbitan monolaurate (manufactured by Kao Co., Ltd., trade name RHEODOL SUPER TW-L120) 3.75 μL, and the surface tension was adjusted to 50±1 mN/m (hereinafter, the same). In addition, the water solubility is measured by adding 0.0001 g of the agent each time. As a result, when it was observed that even 0.0001 g was not dissolved, it was set as "less than 0.0001 g", and when it was observed that 0.0001 g was dissolved but 0.0002 g was not dissolved, it was set as "0.0001 g". The other values are also measured by the same method.

<Method of coating liquid film cracking agent and hydrophilizing agent>

A mixed solution of a diluent and a hydrophilizing agent is prepared by dissolving the above-mentioned polyoxyethylene (POE) modified dimethylpolysiloxane as a solute in an ethanol solution, and each non-woven fabric is immersed in the diluent, and then Dry it.

In the obtained long-fiber nonwoven fabric sample, the content ratio (OPU) of the liquid film cracking agent relative to the fiber mass of the first nonwoven fabric layer and the second nonwoven fabric layer was 0.1% by mass. In addition, the contact angle of the fibers on the first surface side (a) and the second surface side (b) of the first nonwoven fabric layer, and the first surface side (a') and the second surface side (b') of the second nonwoven fabric layer The contact angle of the fiber was measured by the above-mentioned contact angle measurement method, and is shown in Table 1 below. Therefore, the difference between the contact angle of the fibers on the first surface 5 side (a) and the contact angle of the second surface 6 side (b') of the obtained long-fiber nonwoven fabric sample as a whole is 10°, and the first surface 5 side The hydrophilicity of (a) is lower than the hydrophilicity of the second surface 6 side (b'), and has a hydrophilicity gradient from the first surface 5 side (a) to the second surface 6 side (b').

(Example 2)

Use the following agents as liquid film cracking agents, and set the contact angle in the first non-woven fabric layer as follows Except for setting the same as in Table 1, the long-fiber non-woven fabric sample of Example 2 was produced in the same manner as in Example 1.

<Liquid film cracking agent>

As a liquid film cracking agent, X in the structure XY contains _{dimethyl polysiloxane chain containing -Si(CH 3} ) ₂ O-, Y contains _{POP chain containing -(C 3} H ₆ O)-, POP chain The end group is methyl (CH ₃ ), the modification rate is 10%, the polyoxypropylene addition molar number is 10, and the mass average molecular weight is 4340 polyoxypropylene (POP) modified dimethyl Base polysiloxane (obtained by hydroxylation reaction between polysiloxane oil and hydrocarbon compound).

Spread coefficient for liquid with a surface tension of 50mN/m: 26.9mN/m

Surface tension: 21.5mN/m

Interfacial tension to liquid with a surface tension of 50mN/m: 1.6mN/m

Water solubility: 0.0002g

In the obtained long-fiber nonwoven fabric sample, the content ratio (OPU) of the liquid film cracking agent relative to the fiber mass of the first nonwoven fabric layer and the second nonwoven fabric layer was 0.1% by mass. In addition, the contact angle of the fibers on the first surface side (a) and the second surface side (b) of the first nonwoven fabric layer, and the first surface side (a') and the second surface side (b') of the second nonwoven fabric layer The contact angle of the fiber was measured by the above-mentioned contact angle measurement method, and is shown in Table 1 below. Therefore, the difference between the contact angle of the fibers on the first surface 5 side (a) and the contact angle of the second surface 6 side (b') of the obtained long-fiber nonwoven fabric sample as a whole is 11°, and the first surface 5 side The hydrophilicity of (a) is lower than the hydrophilicity of the second surface 6 side (b'), and has a hydrophilicity gradient from the first surface 5 side (a) to the second surface 6 side (b').

(Example 3)

The following agent was used as the liquid film cracking agent, and the contact angle in the second non-woven fabric layer was set as shown in Table 1 below. Except for this, the long fiber of Example 3 was produced in the same manner as in Example 1. Weaving sample.

<Liquid film cracking agent>

As a liquid film cracking agent, the Z in the structure ZY is *-O-CH(CH ₂ O-*) ₂ (* indicates the bonding part), and Y contains C ₈ H ₁₅ O- or C ₁₀ H ₁₉ O- Hydrocarbon chain, fatty acid composition contains caprylic acid 82%, capric acid 18%, and a mass average molecular weight of 550 tricaprylic/capric glycerides (COCONAD MT manufactured by Kao Co., Ltd.).

Spread coefficient for liquid with surface tension of 50mN/m: 8.8mN/m

Surface tension: 28.9mN/m

Interfacial tension to liquid with a surface tension of 50mN/m: 12.3mN/m

Water solubility: less than 0.0001g

In the obtained long fiber nonwoven fabric sample, the content ratio (OPU) of the liquid film cracking agent relative to the fiber mass of the first nonwoven fabric layer and the second nonwoven fabric layer was 0.5% by mass. In addition, the contact angle of the fibers on the first surface side (a) and the second surface side (b) of the first nonwoven fabric layer, and the first surface side (a') and the second surface side (b') of the second nonwoven fabric layer The contact angle of the fiber was measured by the above-mentioned contact angle measurement method, and is shown in Table 1 below. Therefore, the difference between the contact angle of the fiber (a) on the first surface 5 side and the contact angle of the second surface 6 side (b') of the obtained long-fiber nonwoven fabric sample as a whole is 9°, and the first surface 5 side The hydrophilicity of (a) is lower than the hydrophilicity of the second surface 6 side (b'), and has a hydrophilicity gradient from the first surface 5 side (a) to the second surface 6 side (b').

(Example 4)

The following agent was used as the liquid film cracking agent, and the contact angles in the first non-woven fabric layer and the second non-woven fabric layer were set as shown in Table 1 below, except that the same method as in Example 1 was used to produce Example 4 Long fiber non-woven fabric sample.

<Liquid film cracking agent>

As a liquid film cracking agent, Z in the structure ZY contains a _{hydrocarbon chain containing -CH 2} -, Y contains a _{POP chain containing -(C 3} H ₆ O)-, and the addition molar number of polyoxypropylene is 5 POP alkyl ether with a mass average molecular weight of 500 (defoamer No. 8 manufactured by Kao Co., Ltd.).

Spread coefficient for liquid with a surface tension of 50mN/m: 13.7mN/m

Surface tension: 30.4mN/m

Interfacial tension to liquid with surface tension of 50mN/m: 5.9mN/m

Water solubility: less than 0.0001g

In the obtained long fiber nonwoven fabric sample, the content ratio (OPU) of the liquid film cracking agent relative to the fiber mass of the first nonwoven fabric layer and the second nonwoven fabric layer was 5.0% by mass. In addition, the contact angle of the fibers on the first surface side (a) and the second surface side (b) of the first nonwoven fabric layer, and the first surface side (a') and the second surface side (b') of the second nonwoven fabric layer The contact angle of the fiber was measured by the above-mentioned contact angle measurement method, and is shown in Table 1 below. Therefore, the difference between the contact angle of the fibers on the first surface 5 side (a) and the contact angle of the second surface 6 side (b') of the obtained long-fiber nonwoven fabric sample as a whole is 9°, and the first surface 5 side The hydrophilicity of (a) is lower than the hydrophilicity of the second surface 6 side (b'), and has a hydrophilicity gradient from the first surface 5 side (a) to the second surface 6 side (b').

(Example 5)

The weight per unit area was set to 20 g/m ² and the contact angle shown in Table 2 below was used. Except for this, the first non-woven fabric layer was produced in the same manner as in Example 1, and set as the raw material long-fiber non-woven fabric .

Then, the raw long-fiber non-woven fabric is subjected to the raising treatment shown in FIG. 4 to form the first surface side (a) of the first non-woven fabric layer with the free end 42 upright fibers 4, thereby being made to contain the upright fibers 4 and the fiber assembly layer 3 of the long-fiber non-woven fabric sample of Example 5. The two sides of the whole long fiber nonwoven fabric sample correspond to the two sides of the first nonwoven fabric layer, and the test was performed by specifying the first side 5 side (a) and the second side 6 side (b) (hereinafter, Examples 6 to 8) , Comparative Example 3 is the same).

The number of fluffed fibers of this long-fiber nonwoven fabric sample was measured by the measuring method shown in Fig. 5, and it was 18 fibers/cm. That is, the above-mentioned standing fibers 4 are formed on the first surface side (a) of the first nonwoven fabric layer.

In the obtained long-fiber nonwoven fabric sample, the fibers on the side (a) of the first surface 5 (the upright fibers 4 with the free ends 42. The same applies to Examples 6 to 8, and Comparative Example 3) and the second surface 6. The contact angle of the fiber on the side (b) was measured by the above-mentioned contact angle measurement method, and is shown in Table 2 below. Therefore, the obtained long-fiber nonwoven fabric sample has a difference of 10° between the contact angle of the fibers on the first surface 5 side (a) and the second surface 6 side (b), and the first surface 5 side (a) The hydrophilicity is lower than the hydrophilicity of the second surface 6 side (b), and has a hydrophilicity gradient from the first surface 5 side (a) to the second surface 6 side (b).

(Example 6)

The weight per unit area was set to 20 g/m ² and the contact angle shown in Table 2 below was used. Except for this, the first non-woven fabric layer was produced in the same manner as in Example 2, and set as the raw material long-fiber non-woven fabric .

Then, the raw material long-fiber non-woven fabric was subjected to a raising treatment in the same manner as in Example 5 to prepare a long-fiber non-woven fabric sample of Example 6. The number of standing fibers in this long-fiber nonwoven fabric sample was measured by the measuring method shown in Fig. 5, and it was 17 fibers/cm.

In the obtained long-fiber nonwoven fabric samples, the contact angles of the fibers on the first side 5 side (a) and the second side 6 side (b) were measured by the above-mentioned contact angle measurement method, as shown in the following table 2 shown. Therefore, the obtained long-fiber nonwoven fabric sample has a difference of 12° between the contact angle of the fibers on the first surface 5 side (a) and the second surface 6 side (b), and the first surface 5 side (a) The hydrophilicity is lower than the hydrophilicity of the second surface 6 side (b), and has a hydrophilicity gradient from the first surface 5 side (a) to the second surface 6 side (b).

(Example 7)

The weight per unit area was set to 20 g/m ² , and the contact angle shown in Table 2 below was set. Except for this, the first non-woven fabric layer was produced in the same manner as in Example 3, which was set as the raw material long-fiber non-woven fabric .

Then, the raw material long-fiber nonwoven fabric was subjected to a raising treatment in the same manner as in Example 5 to prepare a long-fiber nonwoven fabric sample of Example 7. The number of standing fibers in the long-fiber nonwoven fabric sample was measured by the measuring method shown in Fig. 5, and was 18 fibers/cm.

In the obtained long-fiber nonwoven fabric samples, the contact angles of the fibers on the first side 5 side (a) and the second side 6 side (b) were measured by the above-mentioned contact angle measurement method, as shown in the following table 2 shown. Therefore, the obtained long-fiber nonwoven fabric sample has a difference of 10° between the contact angle of the fiber (a) on the first surface 5 side and the contact angle of the second surface 6 side (b), and the first surface 5 side (a) The hydrophilicity is lower than the hydrophilicity of the second surface 6 side (b) side, and has a hydrophilicity gradient from the first surface 5 side (a) to the second surface 6 side (b).

(Example 8)

The weight per unit area was set to 20 g/m ² and the contact angle shown in Table 2 below was set. Except for this, the first non-woven fabric layer was produced in the same manner as in Example 4, and it was set as the raw material long-fiber non-woven fabric .

Then, the raw material long-fiber nonwoven fabric was raised in the same manner as in Example 5 to prepare a long-fiber nonwoven fabric sample of Example 8. The number of standing fibers in the long-fiber nonwoven fabric sample was measured by the measuring method shown in Fig. 5, and was 18 fibers/cm.

In the obtained long-fiber nonwoven fabric samples, the contact angles of the fibers on the first side 5 side (a) and the second side 6 side (b) were measured by the above-mentioned contact angle measurement method, as shown in the following table 2 shown. Therefore, the obtained long-fiber nonwoven fabric sample has a difference of 11° between the contact angle of the fiber (a) on the first surface 5 side and the contact angle of the second surface 6 side (b), and the first surface 5 side (a) The hydrophilicity of the side is lower than the hydrophilicity of the second surface 6 side (b) side, and has a hydrophilicity gradient from the first surface 5 side (a) to the second surface 6 side (b).

(Comparative example 1)

The liquid film cracking agent and hydrophilizing agent are not applied, except for this, in the same manner as in Example 1 A sample of the long-fiber nonwoven fabric of Comparative Example 1 was prepared.

The contact angle of the fibers on each side of the obtained long-fiber non-woven fabric sample was measured by the above-mentioned contact angle measurement method, and as shown in Table 3 below, there was no difference in contact angle and no gradient of hydrophilicity.

(Comparative example 2)

The long-fiber nonwoven fabric sample of Comparative Example 2 was produced in the same manner as in Example 1, except that the liquid film cracking agent was not applied and the contact angles shown in Table 3 below were set.

The contact angle of the fibers on each side of the obtained long-fiber non-woven fabric sample was measured by the above-mentioned contact angle measurement method, and as shown in Table 3 below, there was no difference in contact angle and no gradient of hydrophilicity.

(Comparative example 3)

Except that the liquid film cracking agent was not applied and the contact angles shown in Table 3 below were set, the long-fiber nonwoven fabric sample of Comparative Example 3 was produced in the same manner as in Example 5.

The contact angle of the fibers on each side of the obtained long-fiber nonwoven fabric sample was measured by the above-mentioned contact angle measurement method, and is shown in Table 3 below. The obtained long-fiber nonwoven fabric sample has a difference of 10° between the contact angle of the fiber (a) on the first side 5 side and the second side 6 side (b) of the long-fiber nonwoven fabric sample, and the first side 5 side (a) is hydrophilic The degree is lower than the degree of hydrophilicity of the second surface 6 side (b), and has a degree of hydrophilicity gradient from the first surface 5 side (a) to the second surface 6 side (b).

(Evaluation test)

The following evaluation tests of "1. Liquid Remaining Test", "3. Liquid Return Test" and "4. Liquid Absorption Time Test" are from disposable diapers (Kao Co., Ltd.) as an example of absorbent articles Manufacturing: Merries (registered trademark) Merries pants L size, manufactured in 2014) remove the front sheet and replace it with each long-fiber non-woven fabric sample as a front sheet for accumulation The periphery of the layer was fixed to obtain a disposable diaper for evaluation, and the evaluation was performed using this disposable diaper for evaluation. In addition, the disposable diapers for evaluation of Examples 1 to 8 and Comparative Examples 1 to 3 were produced for each test. Regarding "2. Liquid flow length test", as described below, each sample was used as a top sheet, and a sample for evaluation was prepared separately.

1. Liquid residue test

Waist wrinkles and leg wrinkles were removed from the disposable diapers for each evaluation, and the front sheet was fixed on a horizontal surface with the front sheet facing upward in the unfolded state. In a non-pressurized state, a total of 160 g of artificial urine was injected into the front sheet of the diaper at a position 125 mm from the front end of the end on the abdominal side in the longitudinal direction of the covering sheet covering the absorbent body. The artificial urinary system was injected with 40 g every 10 minutes, and injected 4 times at an injection rate of 5 g/sec. 10 minutes after the fourth injection, cut the front sheet on a square with a side length of 100 mm centered on the artificial urine injection point, and measure the weight (W1) of the front sheet. Then, the cut-out surface sheet is dried, the weight (W2) of the surface sheet after drying is measured, and the weight difference before and after drying (W1-W2) is calculated as the residual amount of liquid. Perform the above operation 3 times, and set the average value of the 3 times as the residual liquid amount (mg). The amount of residual liquid is an indicator of how moist the wearer’s skin is. The smaller the amount of residual liquid, the better the result. Furthermore, the artificial urinary system used composition is 1.94% by weight of urea, 0.795% by weight of sodium chloride, 0.11% by weight of magnesium sulfate, 0.062% by weight of calcium chloride, 0.197% by weight of potassium sulfate, 0.010% by weight of Red No. 2 (dye), 96.88% by weight of water and polyoxyethylene lauryl ether (about 0.07%), and the surface tension is adjusted to 53±1 dyne/cm (23°C).

2. Liquid flow length test

The test device uses a mounting part with the mounting surface of the test sample inclined at 45° with respect to the horizontal plane. Prepare a sample sample of an absorber by using each sample as a front sheet and superimposing the front sheet with 2 sheets of toilet paper folded in half, and place the test samples for the above evaluation with the front sheet facing upward The way is placed on the placement part. The colored deionized water as the test liquid was dropped onto the test sample at a speed of 1 g/10 sec. Measure the distance from the place where the non-woven fabric is first wetted to the place where the test solution is first absorbed by the absorbent body. Perform the above operation 3 times, and set the average value of the 3 times as the liquid flow length (mm). The liquid flow length is an indicator of how easily the liquid flows on the surface without being absorbed by the test sample, and how easily it comes into contact with the skin during wearing, and whether it becomes easy to leak. The shorter the liquid flow length, the higher the evaluation.

3. Liquid return test

Waist wrinkles and leg wrinkles were removed from the disposable diapers used in the above evaluations, and the front sheet was fixed on a horizontal surface with the front sheet facing upward in the unfolded state. A cylindrical acrylic plate with a spout was placed on the front sheet, and on the acrylic plate, a weight of 2 kg was placed on the back side and the belly side of the diaper to apply a load. The injection port provided in the acrylic plate is formed in the shape of a cylinder with an inner diameter of 36mm (height 53mm). On the acrylic plate, an axis and the axis are formed at the position of 1/3 of the length and the center of the width direction. The center of the cylindrical injection port is the same, and the inside of the cylindrical injection port is connected with the through hole of 36mm inside diameter of the facing surface of the acrylic plate. The acrylic plate is arranged so that the central axis of the cylindrical injection port of the acrylic plate is located 125mm from the front end of the diaper on the abdominal side of the covering sheet covering the absorbent body in the longitudinal direction. The amount of artificial urine is 160g. The artificial urinary system is injected with 40g every 10 minutes, and the injection is divided into 4 times. Ten minutes after the fourth injection, the acrylic plate was removed, and 16 sheets of filter paper (5C manufactured by Toyo Roshi Kaisha Co., Ltd.) were superimposed on a front sheet with a side length of 100 mm centered on the artificial urine injection point, and then applied on it Load for 2 minutes, and the artificial urine will be absorbed by the filter paper. The load is 3.5kg applied to an area of 100mm×100mm. After 2 minutes, remove the load, measure the weight (W4) of the filter paper that has absorbed artificial urine, and use the difference (W4-W3) from the weight of the filter paper before absorption (W3) measured in advance as the amount of liquid return. Figure out. Carry out the above operation 3 times, and set the average value of the 3 times as the liquid back volume (g). Less, the more difficult it is for liquid back to occur, and the evaluation is high.

4. Liquid absorption time test

In the evaluation of the above-mentioned liquid return test, the time until 160 g is completely absorbed by the diaper is measured. The above operations are performed 3 times, and the average value of the 3 times is defined as the liquid absorption time (seconds). The shorter the liquid absorption time, the faster the liquid passes and the higher the evaluation is.

As shown in the above-mentioned Tables 1 to 3, all the evaluation items of Examples 1 to 8 are superior compared to Comparative Examples 1 and 2 without a liquid film cracking agent, a hydrophilicity gradient, and a raised fiber.

In addition, compared with Comparative Example 3 which does not have a liquid film cracking agent, Examples 1 to 8 all show good results with a small amount of residual liquid. In addition, Examples 1 to 8 showed good results equivalent to or higher than Comparative Example 3 in terms of liquid flow rate, liquid residual amount, and liquid absorption time as Comparative Example 3 having a hydrophilicity gradient and raised fibers.

The present invention has been described together with its embodiments and examples, but as long as the inventor does not specify otherwise, the present invention is not limited by any details of the description, and it is considered that it should not deviate from the following details. The spirit and scope of the invention shown in the scope of the patent application are attached and explained in a wide range.

This application claims priority based on Japanese Patent Application No. 2016-109599 filed in Japan on May 31, 2016. The content of this application is hereby referred to and incorporated herein as part of the description of this specification. in.

Claims (15)

A long-fiber non-woven fabric containing a compound (C1), the compound (C1) has a water solubility of 0g or more and 0.025g or less, a spread coefficient for a liquid with a surface tension of 50mN/m of 15mN/m or more, and a surface tension of 21mN/m or more and 30mN/m or less. A long-fiber non-woven fabric containing a compound (C1), the compound (C1) has a water solubility of 0g or more and 0.025g or less, a spreading coefficient for a liquid with a surface tension of 50mN/m of 20mN/m or more, and a surface tension of Those above 21mN/m. A long-fiber non-woven fabric containing one or more selected from compound (C1) and compound (C2), the compound (C1) is a liquid with a water solubility of 0g or more and 0.025g or less, and a surface tension of 50mN/m For those with a spreading coefficient of 15mN/m or more, the compound (C2) has a water solubility of 0g or more and 0.025g or less, the spreading coefficient for liquids with a surface tension of 50mN/m is greater than 0mN/m, and the surface tension is 50mN When the interfacial tension of the liquid is 20mN/m or less, the long-fiber nonwoven fabric contains heat-fusible fibers, and has a first surface that becomes a liquid receiving surface and a second surface located on the opposite side of the first surface. The hydrophilicity of the long fibers on the first surface side is lower than the hydrophilicity of the long fibers on the second surface side, and the contact angle (V1) of the long fibers on the first surface side and the contact angle of the long fibers on the second surface side ( The difference (V1-V2) of V2) is 3° or more, and the contact angle of the long fiber on the second surface side is 77° or more. A long-fiber non-woven fabric containing a liquid film cracking agent. The liquid film cracking agent has a water solubility of 0g or more and 0.025g or less, and has a spreading coefficient of 15mN/m or more for a liquid with a surface tension of 50mN/m. The surface tension is 21mN/m or more and 30mN/m or less. A long-fiber non-woven fabric containing a liquid film cracking agent. The liquid film cracking agent has a water solubility of 0g or more and 0.025g or less, and has a spreading coefficient of 20mN/m or more for a liquid with a surface tension of 50mN/m, and a surface tension of Those above 21mN/m. A long-fiber non-woven fabric containing the following liquid film cracking agent. The long-fiber non-woven fabric contains heat-fusible fibers and has a first surface that becomes a liquid receiving surface and a second surface located on the opposite side of the first surface. The hydrophilicity of the long fibers on the first surface side is lower than the hydrophilicity of the long fibers on the second surface side, and the contact angle (V1) of the long fibers on the first surface side and the contact angle of the long fibers on the second surface side ( The difference (V1-V2) of V2) is 3° or more, and the contact angle of the long fibers on the second surface side is 77° or more. Liquid film cracking agent: Contains selected from water solubility of 0g or more and 0.025g or less and Compounds with a liquid with a surface tension of 50mN/m and a spreading coefficient of 15mN/m or more, and a compound with a water solubility of 0g or more and 0.025g or less, and a liquid with a surface tension of 50mN/m that has a spreading coefficient of more than 0mN/m. A liquid with a surface tension of 50mN/m and an interfacial tension of 20mN/m or less among the compounds. The long-fiber non-woven fabric according to any one of claims 1 to 6, wherein the interfacial tension of the compound (C1) or the liquid film cracking agent to a liquid with a surface tension of 50 mN/m is 20 mN/m or less. The long-fiber nonwoven fabric according to any one of claims 1 to 6, wherein the compound (C1) or the liquid film cracking agent comprises a compound selected from the following formulas [I], [III] and [IV] At least one polyoxyalkylene-modified polysiloxane in the group, the surface tension of the polyoxyalkylene-modified polysiloxane is 21mN/m or more and 30mN/m or less,

In the formula, R ³¹ represents an alkyl group (preferably carbon number 1-20, for example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, 2-ethyl Hexyl, nonyl, decyl); R ³² represents a single bond or alkylene (preferably carbon number 1-20, for example, preferably methylene, ethylene, propylene, butylene), more Preferably, it represents the above-mentioned alkylene group; a plurality of R ³¹ and a plurality of R ³² may be the same or different from each other; M ¹¹ represents a group having a polyoxyalkylene group, preferably a polyoxyalkylene group; as the above-mentioned polyoxyalkylene group Examples of the oxyalkylene group include: polyoxyethylene, polyoxypropylene, polyoxyethylene, or copolymerized monomers such as these; m and n are each independently an integer of 1 or more ; Furthermore, the symbols of the repeating units are determined in each of the formulas [I], [III] and [IV], which do not necessarily represent the same integer, but may be different. The long-fiber nonwoven fabric according to any one of claims 1 to 6, wherein the compound (C1) or the liquid film cracking agent comprises a compound selected from the following formulas [I], [III] and [IV] At least one type of polyoxyalkylene-modified polysiloxane in the group, the spreading coefficient of the polyoxyalkylene-modified polysiloxane to a liquid with a surface tension of 50mN/m is more than 20mN/m, the The surface tension of polyoxyalkylene modified polysiloxane is above 21mN/m,

In the formula, R ³¹ represents an alkyl group (preferably carbon number 1-20, for example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, 2-ethyl Hexyl, nonyl, decyl); R ³² represents a single bond or alkylene (preferably carbon number 1-20, for example, preferably methylene, ethylene, propylene, butylene), more Preferably, it represents the above-mentioned alkylene group; a plurality of R ³¹ and a plurality of R ³² may be the same or different from each other; M ¹¹ represents a group having a polyoxyalkylene group, preferably a polyoxyalkylene group; as the aforementioned polyoxyalkylene group Examples of the oxyalkylene group include: polyoxyethylene, polyoxypropylene, polyoxybutylene, or copolymerized monomers such as these; m and n are each independently an integer of 1 or more ; Furthermore, the symbols of the repeating units are determined in each of the formulas [I], [III] and [IV], which do not necessarily represent the same integer, but may be different. The long-fiber nonwoven fabric of claim 3 or 6, wherein the compound (C2) or the liquid film cracking agent comprises a compound having at least one structure selected from the group consisting of the following structures Z, ZY, and YZY, Structure Z means that >C(A)-(C: carbon atom), -C(A) ₂ -, -C(A)(B)-, >C(A)-C(R ³ )<, >C (R ³ )-, -C(R ³ )(R ⁴ )-, -C(R ³ ) ₂ -, >C< any one of the basic structure repeats, or a combination of two or more of the structure formed by the hydrocarbon chain ; Has a hydrogen atom at the end of structure Z, or is selected from -C(A) ₃ , -C(A) ₂ B, -C(A)(B) ₂ , -C(A) ₂ -C(R ³ ) ₃ , -C(R ³ ) ₂ A, -C(R ³ ) ₃ at least one group in the group consisting of; the above R ³ or R ⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, Aryl, fluoroalkyl, aralkyl, or a combination of hydrocarbon groups or fluorine atoms; A and B each independently represent a substituent containing an oxygen atom or a nitrogen atom; in the structure Z, R ³ , R ^{4. When} there are a plurality of A and B, they may be the same or different from each other; Y means that it contains an atom selected from hydrogen atom, carbon atom, oxygen atom, nitrogen atom, phosphorus atom, and sulfur atom, which has hydrophilicity. Sexual hydrophilic group; when Y is plural, they can be the same or different from each other. The long-fiber non-woven fabric of any one of claims 1, 2, 4, and 5, which contains heat-fusible fibers, has a first surface and a second surface located on the opposite side of the first surface, and the first surface side The hydrophilicity of the fiber is lower than the hydrophilicity of the fiber on the second surface side. The long-fiber non-woven fabric according to any one of claims 1, 2, 4, and 5, wherein the long-fiber non-woven fabric contains heat-fusible fibers and has a first surface and a second surface located on the opposite side of the first surface, and The difference (V1-V2) between the contact angle (V1) of the fiber on the first surface side and the contact angle (V2) of the fiber on the second surface side (non-skin contact surface side) is 3° or more. Such as the long-fiber non-woven fabric of claim 12, wherein the contact angle of the long-fiber on the second surface side is 77° or more. The long-fiber non-woven fabric according to any one of claims 1 to 6, wherein the long-fiber non-woven fabric contains heat-fusible fibers, has a first surface and a second surface located on the opposite side of the first surface, and the first surface side The fiber is an upright fiber that has a base portion fixed on the fiber assembly layer and a free end that is not fixed to the fiber assembly layer and stands upright. An absorbent article which uses the long-fiber nonwoven fabric according to any one of claims 11 to 14 as a front sheet with the first surface facing the skin contact surface side.

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