JP2019002100A - Nonwoven fabric - Google Patents

Abstract

To provide a nonwoven fabric which achieves improvement in prevention of body fluid running off and reduction in residual liquid at the same time with use of a cleavage agent for a liquid film.MEANS: A nonwoven fabric contains a fiber A having a cleavage agent for a liquid film and a fiber B having hydrophilic properties. The content of the fiber A in the nonwoven fabric is 40 mass% or less relative to the nonwoven fabric.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a nonwoven fabric.

In recent years, proposals have been made to improve the feeling of wear, such as dryness, for non-woven fabrics used for surface materials that touch the skin of absorbent articles. For example, Patent Document 1 describes that a liquid film generated in a narrow space between fibers of a nonwoven fabric can be cleaved with a liquid film cleaving agent to reduce liquid residue in the nonwoven fabric. Thereby, the dryness of a nonwoven fabric can be improved.
In the absorbent article of Patent Document 2, it is described that the surface sheet is formed from a nonwoven fabric in which hydrophilic fibers and water-repellent fibers are mixed in order to absorb body fluid in a limited range without diffusing. Yes. In addition, in Patent Document 3, in the nonwoven fabric composed of the first fiber layer and the second fiber layer, the first fiber layer has a spiral shape in order to adjust the spiral winding and prevent the liquid from staying. It is described to include crimped and non-spiral fibers.

JP, 2006-117981, A JP 2014-73759 A Japanese Patent Laid-Open No. 2015-110846

The inventors of the present invention have been able to reduce the liquid residue of the nonwoven fabric used as the surface material by using the liquid film cleaving agent described in Patent Document 1.
Furthermore, in an absorbent article, about the nonwoven fabric which makes the surface material which touches skin, the improvement of the prevention with respect to the surface flow (runoff) of a bodily fluid is calculated | required with the reduction of a liquid residue. The improvement in the run-off prevention property leads to the liquid permeability in the thickness direction of the nonwoven fabric, and can contribute to the improvement of the liquid leakage prevention property and the liquid absorption property in the absorbent article. In the non-woven fabric, there is no room for further improvement since it is not described in the above-mentioned document about simultaneously improving the surface flow preventing property of body fluid and reducing liquid residue.

  The present invention relates to a non-woven fabric that can simultaneously improve the run-off prevention of body fluids and reduce the remaining liquid by using the liquid film cleaving agent.

The present invention provides a nonwoven fabric containing a fiber A having a liquid film cleaving agent and a hydrophilic fiber B, wherein the fiber A is contained in an amount of 40% by mass or less based on the nonwoven fabric.
The present invention also relates to a fiber A having a compound (C1) having an expansion coefficient of 15 mN / m or more and a water solubility of 0 g to 0.025 g for a liquid having a surface tension of 50 mN / m, and a hydrophilic fiber. A non-woven fabric containing B and 40% by mass or less of the fiber A with respect to the non-woven fabric.
In the present invention, the expansion coefficient for a liquid with a surface tension of 50 mN / m is larger than 0 mN / m, the water solubility is 0 g or more and 0.025 g or less, and the interfacial tension for a liquid with a surface tension of 50 mN / m is 20 mN. The nonwoven fabric which contains the fiber A which has the compound (C2) which is / m or less, and the fiber B which has hydrophilic property, and the said fiber A contains 40 mass% or less with respect to a nonwoven fabric.

  The non-woven fabric of the present invention can simultaneously improve the body fluid run-off prevention and reduce the remaining liquid.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows typically preferable embodiment (1st Embodiment) of the nonwoven fabric which concerns on this invention, and the figure in the circle | round | yen shown with the code | symbol P is the model which expands and shows the state which the fiber A and the fiber B mixed FIG. It is sectional drawing which shows typically another preferable embodiment (2nd Embodiment) of the nonwoven fabric which concerns on this invention. It is a top view which shows typically another preferable embodiment (3rd Embodiment) of the nonwoven fabric which concerns on this invention. It is sectional drawing which expands and partially shows the cross section of the nonwoven fabric in 3rd Embodiment. (A) It is sectional drawing which shows typically the state by which the recessed part at the time of the nonwoven fabric in 3rd Embodiment having multiple layers being distribute | arranged only to 1 layer, (B) is a plurality of nonwoven fabrics in 3rd Embodiment. It is sectional drawing which shows typically the state by which the recessed part at the time of being a layer is distribute | arranged by the depth which joins a some fiber layer.

  About the nonwoven fabric which concerns on this invention, the preferable embodiment is described below, referring drawings. In addition, the nonwoven fabric which concerns on this invention can be applied to various articles | goods which concern on liquid absorption, for example, can be used as absorbent article surface sheets, such as a sanitary napkin, a baby diaper, an adult diaper.

FIG. 1 shows a nonwoven fabric 5 according to the first embodiment.
The nonwoven fabric 5 of 1st Embodiment contains the fiber A which has a liquid film cleaving agent, and the fiber B which has hydrophilic property. The fiber A is contained in an amount of 40% by mass or less with respect to the nonwoven fabric 5. This nonwoven fabric 5 has hydrophilicity that allows the liquid to penetrate in the thickness direction as a whole. In addition, in the nonwoven fabric 5, as long as the fiber A and the fiber B are contained and the fiber A is contained in 40% by mass or less, fibers other than the fiber A and the fiber B may be contained. In addition, in the figure in the circle | round | yen shown with the code | symbol P of FIG. 1, although the fiber A was shown with the pattern for convenience so that the fiber A could be discriminate | determined, it does not show that the actual fiber A has a pattern. Absent.

  In the first embodiment, the fibers A and the fibers B are mixed (mixed cotton) to form the nonwoven fabric 5 without forming respective layers. By the blended cotton, a state in which the liquid film cleaving agent contained in the fiber A is separated from the hydrophilic fiber B is formed in the nonwoven fabric 5, and a pseudo phase separation state is obtained. Moreover, the nonwoven fabric 5 of this embodiment consists of one layer (single layer). However, the nonwoven fabric of this invention is not limited to what consists of one layer, As long as it contains the fiber A as said content rate and the fiber B as a constituent fiber, it may consist of two or more layers.

  The “hydrophilicity” of the fiber B means that the wettability is good without repelling the liquid. Specifically, it means that the contact angle of the fiber B is 80 ° or less. The smaller the contact angle, the better the wettability. A contact angle means the value obtained by the measuring method mentioned later in this invention. The contact angle of the fiber B is smaller than the contact angle of the fiber A. The contact angle of the fiber B is preferably 75 ° or less, more preferably 70 ° or less, and even more preferably 65 ° or less from the viewpoint of improving the wettability of the liquid in the fiber B and increasing the drawability of the liquid into the nonwoven fabric 5. preferable. Further, the contact angle of the fiber B is preferably 0 ° or more, more preferably 10 ° or more, and still more preferably 20 ° or more, from the viewpoint of suppressing liquid return after liquid passage.

  Fiber A has a liquid film cleaving agent so that the contact angle is larger than that of fiber B. This is because the liquid film cleaving agent has a lower surface tension or lower water solubility than conventional hydrophilizing agents used for nonwoven fibers, as will be described later. By doing. The contact angle of the fiber A is larger than that of the fiber B. That is, the fiber A is more hydrophobic than the fiber B. The contact angle of the fiber A is more preferably 10 ° or more and more preferably 20 ° or more than the contact angle of the fiber B from the viewpoint of enhancing the liquid film cleavage effect. Specifically, the contact angle of the fiber A is preferably 85 ° or more, more preferably 90 ° or more, and still more preferably 95 ° or more, from the viewpoint of enhancing the liquid film cleavage effect. The contact angle of the fiber A is preferably 110 ° or less, more preferably 105 ° or less, and still more preferably 100 ° or less, from the viewpoint of keeping the absorption rate fast.

The above contact angle can be measured by the following method.
First, a fiber is taken out from a predetermined part of the nonwoven fabric. At this time, the selection of the fiber A and the fiber B is performed as the fiber A if the contact angle value is 85 ° or more, and as the fiber B if the contact angle value is 80 ° or less. Subsequently, the contact angle of water with respect to each of the selected fibers A and B is measured. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Deionized water is used to measure the contact angle. The measurement is performed at a temperature of 25 degrees and a relative humidity (RH) of 65%. The amount of liquid discharged from an ink jet type water droplet discharge part (manufactured by Cluster Technology Co., Ltd., pulse injector CTC-25 having a discharge part pore diameter of 25 μm) is set to 20 picoliters, and a water drop is dropped directly above the fiber. The state of dripping is recorded on a high-speed recording device connected to a horizontally installed camera. The recording device is preferably a personal computer incorporating a high-speed capture device from the viewpoint of image analysis or image analysis later. In this measurement, an image is recorded every 17 msec. In the recorded video, the first image of water drops on the fiber taken out from the non-woven fabric is attached to the attached software FAMAS (software version is 2.6.2, analysis method is droplet method, analysis method is θ / 2 method) The image processing algorithm is non-reflective, the image processing image mode is frame, the threshold level is 200, and the curvature is not corrected). And the contact angle. The fiber taken out from the nonwoven fabric is cut into a fiber length of 1 mm, and the fiber is placed on a sample table of a contact angle meter and kept horizontal. Two different contact angles are measured for each fiber. N = 5 contact angles are measured to one decimal place, and a value obtained by averaging a total of 10 measured values (rounded to the second decimal place) is defined as the contact angle.

  In the nonwoven fabric 5, the function which improves liquid permeability is shared by the fiber unit of the fiber A and the fiber B. Specifically, the fiber A has a function of cleaving the liquid film with the liquid film cleaving agent to reduce liquid retention (liquid remaining) (details of the liquid film cleaving agent will be described later). The fiber B has a function of drawing liquid by wettability and preventing surface flow from occurring. The liquid film cleaving agent possessed by the fiber A cleaves the liquid film remaining in a very small space between the fibers, and the fiber B is drawn in such a manner that the liquid does not flow out and is shifted in the thickness direction of the nonwoven fabric 5. Further, while the fiber B draws the liquid, the liquid film cleaving agent of the fiber A inhibits the formation of the liquid film, and the liquid is moved in the thickness direction of the nonwoven fabric 5. As a result, the nonwoven fabric 5 increases the prevention of the liquid surface flow (runoff), inhibits the formation of a liquid film between the fibers, reduces the liquid residue, and has excellent liquid permeability in the thickness direction. As a result, the nonwoven fabric 5 has excellent dryness. Moreover, the liquid film cleaving agent is easy to spread in the nonwoven fabric when coming into contact with the liquid due to its expandability, and can move within the nonwoven fabric 5 to express the cleaving action of the liquid. In particular, the diffusion of the liquid film cleaving agent in the thickness direction of the nonwoven fabric 5 promotes drainage in the thickness direction and can contribute to the improvement of liquid permeability and dryness. Such an operation effect in the nonwoven fabric 5 is more effectively expressed especially when the fiber A and the fiber B are mixed. This is due to the fact that the liquid film cleaving agent is pseudo-phase-separated by blending cotton, and the functional sharing and cooperation of the fibers A and B in the nonwoven fabric 5 are suitably expressed.

  In the non-woven fabric 5, considering the expandability of the liquid film cleaving agent, the fiber A is contained in an amount of 40% by mass or less with respect to the non-woven fabric 5, thereby sufficiently exhibiting the liquid film cleaving action and the surface of the liquid. The flow can be effectively prevented. From the same viewpoint, the fiber A is preferably contained in an amount of 35% by mass or less, more preferably 30% by mass or less, and further preferably 25% by mass or less with respect to the nonwoven fabric 5. The fiber A is preferably contained in an amount of 10% by mass or more, more preferably 20% by mass or more with respect to the nonwoven fabric 5, from the viewpoint of effectively expressing the liquid film cleaving action in the nonwoven fabric 5. More preferably, it is contained by mass% or more.

  The liquid film cleaving agent is preferably 0.05% by mass or more, more preferably 0.09% by mass or more from the viewpoint of effectively expressing the liquid film cleaving action as a content ratio to the fiber A mass (Oil Per Unit). 0.14% by mass or more is more preferable. In addition, the content of the liquid film cleaving agent (OPU) with respect to the mass of the fiber A is 0.4% by mass or less from the viewpoint of effectively suppressing the surface flow of the liquid and improving the touch of the nonwoven fabric. Preferably, 0.3 mass% or less is more preferable, and 0.2 mass% or less is still more preferable. In addition, the content rate (OPU) in the fiber A of the liquid film cleaving agent can be measured by applying the method described in paragraph [0018] of the specification of International Publication No. 2016/098796.

The liquid film cleaving agent is an agent having the following (property that causes the liquid film to disappear). Specifically, liquids such as highly viscous liquids such as menstrual blood and excretion liquids (body fluids) such as urine touch the nonwoven fabric to cleave the liquid film formed between the fibers of the nonwoven fabric or on the fiber surface. It means an agent that inhibits the formation of a liquid film, and has an action of cleaving the formed liquid film and an action of inhibiting the formation of the liquid film. The former can be called the main action, and the latter can be called the subordinate action. For example, the liquid film cleaving agent acts as described in paragraphs [0024] and [0025] and FIGS. 1 and 2 of the specification of WO2016 / 098796. In this way, the liquid film cleaving agent does not perform liquid modification such as lowering the surface tension of the liquid film, but cleaves and pushes away the liquid film itself generated between the fibers or on the fiber surface, thereby inhibiting it from the nonwoven fabric. Encourage drainage of liquid.
Due to the above action of the liquid film cleaving agent, the liquid (body fluid) touching the non-woven fabric can easily pass through without staying in a very small space between the fibers, and the liquid remaining in the non-woven fabric can be reduced at a higher level.

(Characteristic of disappearing liquid film)
The liquid film cleaving agent used in the present invention has the property of eliminating the liquid film, and due to this property, the liquid film cleaving agent is applied to a test liquid or artificial urine mainly composed of plasma components. Moreover, the liquid film disappearance effect can be expressed. Artificial urine is 1.940% by weight of urea, 0.795% by weight of sodium chloride, 0.110% by weight of magnesium sulfate, 0.062% by weight of calcium chloride, 0.197% by weight of potassium sulfate, red No. 2 (dye) 0 The surface tension of a mixture having a composition of 0.010% by weight, water (about 96.88% by weight) and polyoxyethylene lauryl ether (about 0.07% by weight) was adjusted to 53 ± 1 mN / m (23 ° C.). Is. The liquid film disappearance effect here refers to the effect of inhibiting the liquid film formation of the structure and the formed structure of the structure in which air is held by the liquid film formed from the test liquid or artificial urine. It can be said that an agent that exhibits both of the effects of disappearing the body and that exhibits at least one of the effects has the property of exhibiting the effect of disappearing the liquid film.
The test solution is a liquid component extracted from defibrinated horse blood (manufactured by Nippon Biotest Co., Ltd.). Specifically, when 100 mL of defibrinated horse blood is allowed to stand at a temperature of 22 ° C. and a humidity of 65% for 1 hour, the defibrinated horse blood is separated into an upper layer and a lower layer. It is. The upper layer mainly contains plasma components, and the lower layer mainly contains blood cell components. In order to take out only the upper layer from defibrinated horse blood separated into an upper layer and a lower layer, for example, a transfer pipette (manufactured by Nippon Micro Corporation) can be used.
Whether or not an agent has the above-mentioned property of “disappearing a liquid film” depends on whether a liquid film formed from the test solution or artificial urine to which the agent is applied generates a structure that is trapped in air. It is judged by the amount of the structure, that is, the liquid film when it is in a state where it is easy to do. That is, the test solution or artificial urine is adjusted to a temperature of 25 ° C., and then 10 g is put into a screw tube (No. 5 body diameter 27 mm, total length 55 mm, manufactured by Maruemu Co., Ltd.) to obtain a standard sample. In addition, a measurement sample obtained by adding 0.01 g of an agent to be measured, which is adjusted in advance to 25 ° C., to the same sample as the standard sample is obtained. The standard sample and the measurement sample are vigorously shaken twice in the vertical direction of the screw tube, and then quickly placed on a horizontal plane. By shaking the sample, the structure of the liquid layer (lower layer) without the structure and a large number of structures formed on the liquid layer (the lower layer) is formed inside the screw tube after shaking. Upper layer). After the elapse of 10 seconds immediately after shaking, the height of the structure layers of both samples (the height from the liquid surface of the liquid layer to the upper surface of the structure layer) is measured. Then, when the height of the structure layer of the measurement sample is 90% or less with respect to the height of the structure layer of the standard sample, it is assumed that the agent to be measured has a liquid film cleavage effect.
The liquid film cleaving agent used in the present invention satisfies the above properties by a single compound that applies to the above properties, a mixture of a plurality of single compounds that apply to the above properties, or a combination of a plurality of compounds (liquid Agent capable of developing membrane cleavage). That is, the liquid film cleaving agent is an agent limited to those having a liquid film cleaving effect as defined above. Therefore, when the compound applied in the absorbent article contains a third component that does not meet the above definition, it is distinguished from a liquid film cleaving agent.
In addition, regarding the liquid film cleaving agent and the third component, the “single compound” is a concept including compounds having the same composition formula but having different molecular weights due to different numbers of repeating units.
As the liquid film cleaving agent, it can be appropriately selected from those described in paragraphs [0007] to [0186] of the specification of International Publication No. 2016/098796. Preferred embodiments of the liquid film cleaving agent will be further described later.

  That fiber A contains or has a liquid film cleaving agent mainly means that it adheres to the surface of the fiber. However, as long as the liquid film cleaving agent remains on the surface of the fiber, there may be a liquid film cleaving agent that is encapsulated in the fiber or that is present inside the fiber by internal addition. As a method for forming the fiber A by adhering a liquid film cleaving agent to the surface of the fiber, various commonly used methods can be employed without any particular limitation. For example, application by spraying, application by a slot coater, application by roll transfer, immersion, etc. may be mentioned for the raw material fibers before manufacturing the nonwoven fabric. This treatment can be performed on various fibers. For example, it may be performed on a hydrophobic chemical fiber, and the fiber having hydrophilicity similar to the fiber B (hydrophobic chemical fiber hydrophilized by a normal method, natural fiber, regenerated cellulose fiber) You may do it for. The fiber having the liquid film cleaving 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, for example, a hot air blowing type dryer. Moreover, when attaching to a fiber using the said attachment method, you may use the solution containing the liquid film cleaving agent which dissolved the liquid film cleaving agent in the solvent if necessary, or the emulsion of liquid film cleaving agent, and a dispersion liquid. . In order for the liquid film cleaving agent to have a liquid film cleaving effect to be described later in the nonwoven fabric, the liquid film cleaving agent needs to exist as a liquid when it comes into contact with body fluid. From this point, the melting point of the liquid film cleaving agent is preferably 40 ° C. or less, and more preferably 35 ° C. or less. Furthermore, the melting point of the liquid film cleaving agent according to the present invention is preferably −220 ° C. or higher, more preferably −180 ° C. or higher.

  The nonwoven fabric 5 of 1st Embodiment can be manufactured with the various manufacturing method of the nonwoven fabric used normally using said fiber A and fiber B. FIG.

Next, another preferred embodiment (second embodiment) of the nonwoven fabric of the present invention will be described.
In 2nd Embodiment, the nonwoven fabric consists of multiple layers laminated | stacked in the thickness direction, and the fiber A is unevenly distributed in the fiber layer of one surface side, and is mixed with the fiber B. Also in this case, the fiber A is contained in an amount of 40% by mass with respect to the entire nonwoven fabric (entire layers). The content ratio of the fiber A is preferably set to a preferable content ratio shown for the nonwoven fabric 5 of the first embodiment. Here, the fiber A is unevenly distributed means that 80% by mass or more of the fiber A contained in the entire nonwoven fabric is present in the fiber layer on one surface side, preferably 90% by mass or more, and 95% by mass or more. More preferred is 100% by mass.

  The nonwoven fabric of 2nd Embodiment forms the several fiber web which varied the content rate of the fiber A, laminates and forms a nonwoven fabric, or forms the several nonwoven fabric from which the content rate of the fiber A varied It can be manufactured by a method of laminating and bonding.

FIG. 2 shows a specific example of the nonwoven fabric of the second embodiment.
The nonwoven fabric 6 of 2nd Embodiment consists of the 1st fiber layer 61 by the side of the 1st surface T1 which is one surface, and the 2nd fiber layer 62 by the side of the 2nd surface T2 which is an opposite surface. The first fiber layer 61 is composed of fibers A and fibers B. The second fiber layer 62 is made of fiber B and does not contain fiber A. In the first fiber layer 61, the liquid film cleaving agent described above acts in the direction of increasing the contact angle of the fiber A. Therefore, the hydrophilicity of the first fiber layer 61 containing the fiber A is made lower than that of the second fiber layer 62 not containing the fiber A. As a result, the nonwoven fabric 6 has hydrophilicity that allows the liquid to pass through in the thickness direction as a whole, but the hydrophilicity on the second surface T2 side is higher than the first surface T1 side due to the uneven distribution of the fibers A. ing. The level of hydrophilicity mentioned here is indicated by the magnitude of the contact angle obtained by the measurement method described above for the fiber. The larger the contact angle, the lower the hydrophilicity.
In 2nd Embodiment, the drawing-in force of the liquid from the 1st surface T1 side of the nonwoven fabric 6 to the 2nd surface T2 side arises by the said hydrophilicity difference. The liquid pull-in force due to the difference in hydrophilicity between the layers and the liquid pull-in force due to the mixed cotton of the fibers A and B described above cooperate to further increase the liquid permeability in the nonwoven fabric thickness direction. Further, the liquid film cleaving agent exhibits a liquid film cleaving action in the whole nonwoven fabric due to its extensibility, as in the case where there is no uneven distribution of the fiber A, and the liquid remaining in the whole nonwoven fabric 6 as well as the first fiber layer 61. Reduction can be realized. Thereby, the nonwoven fabric 6 can implement | achieve higher dryness.
The nonwoven fabric 6 is not limited to two layers, and may be composed of three or more fiber layers as long as the fibers A are unevenly distributed on one surface side like the first fiber layer 61. Good. Moreover, in the nonwoven fabric which consists of a single layer, the form where the fiber A is unevenly distributed in one surface side may be sufficient.

Next, still another preferred embodiment (third embodiment) of the nonwoven fabric of the present invention will be described.
FIG. 3 shows a nonwoven fabric 7 having a recess as the nonwoven fabric of the third embodiment.
In the nonwoven fabric 7 of the third embodiment, a plurality of concave portions 71 are arranged in the plane direction on the first surface T1 side which is one surface. The planar shape of the recess 6 is not limited to that shown in FIG. 3 and can take various shapes. For example, the shape may be a circle, an ellipse, a triangle, a rectangle, a diamond, a heart shape, or a combination thereof. Further, the size, number, and arrangement position of the recesses 6 are not limited to those shown in FIG. 3 and can take various forms. In the third embodiment, a portion surrounded by the plurality of concave portions 71 is a convex portion 72 on the first surface T1 side. The convex portions 72 each have an independent dome shape. In addition, although the nonwoven fabric 7 was shown as a single layer nonwoven fabric which consists of the fiber layer 78, it is not limited to this, You may consist of a some fiber layer so that it may mention later.

  The recess 71 is a portion where the fiber layer is squeezed by embossing or the like. At the bottom 73 of the recess 71 (hereinafter also referred to as the recess bottom 73), as shown in FIG. 4, the constituent fibers are heat-sealed by the pressing, and the distance between the fibers is made extremely narrower than other portions. Is in a state. Depending on the case, it may have the film surface which consists of a resin component of a fiber. Thus, the recessed part bottom part 73 is a junction part of the fibers formed by densely fusing the fibers.

  The nonwoven fabric 7 contains fibers A and B, and the fibers A are contained in an amount of 40% by mass or less with respect to the nonwoven fabric 5. The content ratio of the fiber A is preferably set to a preferable content ratio shown for the nonwoven fabric 5 of the first embodiment. The nonwoven fabric 7 may be composed of a single layer or may be composed of a plurality of layers. Moreover, the nonwoven fabric 7 may be one in which the recess 71 is incorporated into the nonwoven fabric 5 of the first embodiment or the nonwoven fabric 6 of the second embodiment, and the recess 71 is formed in the nonwoven fabric combining the first embodiment and the second embodiment. It may be incorporated. When the fiber A is unevenly distributed on one surface side as in the second embodiment, it is preferable to form the recess 71 on the surface on the side where the fiber A is unevenly distributed.

In the nonwoven fabric 7, a dense portion 74 of fibers A is arranged around the recess bottom 72 as shown in FIGS. 3 and 4. Here, “dense” means a state where the fiber density is locally high. Such a dense portion 74 can be formed by subjecting the nonwoven fabric containing the fiber A to a crimping process such as hot embossing or ultrasonic embossing.
In the recess bottom 73, the fiber density is increased by squeezing, so that the liquid is easily drawn on the first surface T1 side in combination with the shape of the recess 71. The presence of the dense portion 74 of the fibers A around the bottom portion 73 of the recess allows the liquid film to be efficiently cleaved with the liquid flow suppressed. Thereby, the nonwoven fabric 7 can implement | achieve the improvement of the prevention of the surface flow (runoff) of a bodily fluid, and liquid remaining reduction more reliably. As a result, the nonwoven fabric 7 has excellent liquid permeability and higher dryness.
The nonwoven fabric 7 preferably has an uneven surface formed by the recess 71 and the dome-shaped protrusion 72 from the viewpoint of further increasing the pulling force of the liquid into the recess bottom 73. The shape of the uneven surface can make it difficult for the liquid to flow on the first surface T <b> 1, and the liquid is concentrated on the bottom portion 72 of the recess. This also leads to an improvement in liquid surface flow (runoff) prevention. In addition, from the viewpoint of further enhancing the liquid flow preventing property and the pulling force of the liquid into the concave bottom portion 73, it is preferable that the hydrophilicity of the convex portions 72 is higher than the hydrophilicity of the dense portions 74 in the nonwoven fabric 7. Thereby, the liquid can be reliably caught by the convex portion 72 to prevent the liquid surface from flowing, and the liquid can be drawn into the dense portion 74 around the concave bottom portion 72. The difference in hydrophilicity between the convex portion 72 and the dense portion 74 can be performed by various methods. For example, it is possible to reduce the content of the fiber A in the convex portion 72 rather than the dense portion 74.

  In the third embodiment, the dense portion 74 may be arranged to extend to the concave bottom portion 73 as long as it is in the vicinity of the concave bottom portion 73 and exhibits the above-described action, and extends to a part of the convex portion 7. It may be spread out.

  The separation distance between the adjacent recesses 71 is preferably 20 mm or less, more preferably 15 mm or less, and even more preferably 10 mm or less, from the viewpoint of more effectively expressing the action by the dense portion 74 of the fiber A around the recess bottom 73. . In addition, the separation distance between the adjacent recesses 71 is preferably 0.1 mm or more, more preferably 0.5 mm or more, and still more preferably 1 mm or more, from the viewpoint of suppressing a decrease in liquid drawability.

(Measuring method of the separation distance (H1) of the recess 6)
The distance between the centers of the eight embossed points is measured with a ruler using a magnifying glass such as a loupe, and the average value measured at five or more locations is taken as the separation distance of the recess 6.

  Although the nonwoven fabric 7 of 3rd Embodiment was shown as a nonwoven fabric consisting of a single layer, as long as it has the recessed part 71 and the dense part 74 of the fiber A around the recessed part bottom part 73, it is not limited to this, Even if it consists of a several fiber layer Good. When the nonwoven fabric 7 consists of a some fiber layer, the recessed part 71 may be formed only in one fiber layer, and may be formed in the depth which joins the fiber layers to laminate | stack. As a specific example in case the nonwoven fabric 7 consists of a some fiber layer, what consists of two layers is shown in FIG. 5 (A) and (B). In FIG. 5A, the recess 71 is formed only in the fiber layer 78 on the first surface T 1 side, and the recess 71 does not reach the adjacent fiber layer 79. In this case, the recess bottom 73 is a joint between the constituent fibers of the fiber layer 78. The dense portion 74 of the fibers A around the recess bottom portion 73 is disposed in the fiber layer 78. On the other hand, in FIG. 5 (B), the recessed part 71 is formed with the depth which joins the fiber layer 78 by the side of the 1st surface T1, and the fiber layer 79 adjacent. In this case, the recess bottom 73 is a joint between the fiber layers 78 and 79. The dense portion 74 of the fibers A around the recess bottom portion 73 is disposed on the fiber layers 78 and 79. In addition, when the nonwoven fabric 7 has three or more fiber layers, and the recessed part bottom part 73 is a junction part of fiber layers, the recessed part bottom part 73 is not restricted to the case where 2 layers are joined like FIG. 5 (B). Three or more layers may be joined (not shown). Further, on the second surface T2 side, which is the opposite surface of the first surface T1 of the nonwoven fabric 7, another recess may be disposed at a position corresponding to the recess 71 of the first surface T1 (not shown).

  The first embodiment, the second embodiment, and the third embodiment described above can be implemented in combination with each other.

  Next, a preferred embodiment of the liquid film cleaving agent will be described. Preferable embodiments of the liquid film cleaving agent include those described in paragraphs [0013] to [0088] of WO2016 / 098796. Specifically, the thing of the following 1st embodiment and 2nd embodiment is mentioned.

The liquid film cleaving agent of the first embodiment has an expansion coefficient of 15 mN / m or more and a water solubility of 0 g or more and 0.025 g or less for a liquid having a surface tension of 50 mN / m. A compound having this property may be referred to as compound C1.
The liquid film cleaving agent of the second embodiment has an expansion coefficient larger than 0 mN / m for a liquid having a surface tension of 50 mN / m, that is, a positive value, and has a water solubility of 0 g or more and 0.025 g or less, The interfacial tension for a liquid having a tension of 50 mN / m is 20 mN / m or less. A compound having this property may be referred to as compound C2.

The definition of “expansion coefficient for a liquid with a surface tension of 50 mN / m” and “water solubility” of the liquid film cleaving agent defined in the first and second embodiments, and the liquid film (with a surface tension of 50 mN / m) Liquid) surface tension (γ _w ), liquid film cleaving agent surface tension (γ _o ), liquid film cleaving agent interfacial tension (γ _{w o} ), and liquid film cleaving agent water solubility measurement methods , As described in paragraphs [0015] to [0022] of International Publication No. 2016/098796.

  In the liquid film cleaving agent of the first embodiment, the expansion coefficient is 15 mN / m or more, so that the liquid film cleaving agent has mobility on the surface of the liquid film generated in a narrow space region between fibers, that is, diffusion. It becomes a high quality thing. Furthermore, a liquid film cleaving agent also has the expansibility which moves to the other area | region from the position of the fiber A which comprises a nonwoven fabric. From the viewpoint of sufficiently exhibiting these expandability, the expansion coefficient of the liquid film cleaving agent is more preferably 20 mN / m or more, further 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 from the formula (1) described in paragraph [0015] of International Publication No. 2016/098796, the upper limit value is obtained when a liquid having a surface tension of 50 mN / m is used. When a liquid with a surface tension of 60 mN / m is used, the upper limit is 60 mN / m. When a liquid with a surface tension of 70 mN / m is used, the upper limit is 70 mN / m. The surface tension of the liquid forming the film is the upper limit. Therefore, in the present invention, from the viewpoint of using a liquid having a surface tension of 50 mN / m, it is 50 mN / m or less.

Further, in the liquid film cleaving agent of the first embodiment, the water solubility is 0 g or more and 0.025 g or less, so that the liquid film cleaving agent is difficult to dissolve and forms an interface with the liquid film, and thus the diffusion described above. Make sex more effective. From the same viewpoint, the water solubility of the liquid film cleaving agent is preferably 0.0025 g or less, more preferably 0.0017 g or less, and still more preferably less than 0.0001 g. The water solubility is preferably as small as possible, and is 0 g or more. From the viewpoint of diffusibility into the liquid film, it is practical to set the water solubility to 1.0 × 10 ⁻⁹ g or more. In addition, it is thought that said water solubility is applicable also to the menstrual blood, urine, etc. which have a water | moisture content as a main component.

The liquid film cleaving agent of the first embodiment preferably further has an interface tension of 20 mN / m or less with respect to a liquid having a surface tension of 50 mN / m. That is, it is preferable that the “interfacial tension (γ _wo ) of the liquid film cleaving agent with respect to the liquid film”, which is one variable for determining the value of the expansion coefficient (S) in the above-described mathematical formula (1), is 20 mN / m or less. By keeping the “interfacial tension of the liquid film cleaving agent (γ _wo ) with the liquid film” low, the expansion coefficient of the liquid film cleaving agent is increased, and the liquid film cleaving agent is likely to move from the fiber surface to the vicinity of the liquid film center. The above-described action becomes clearer. From this viewpoint, the “interfacial tension with respect to a liquid having a surface tension of 50 mN / m” of the liquid film cleaving agent is more preferably 17 mN / m or less, further preferably 13 mN / m or less, still more preferably 10 mN / m or less, and 9 mN. / M or less is particularly preferable, and 1 mN / m or less is particularly preferable. On the other hand, the lower limit is not particularly limited, and may be larger than 0 mN / m from the viewpoint of insolubility in the liquid film. Note that when the interfacial tension is 0 mN / m, that is, when dissolved, an interface between the liquid film and the liquid film cleaving agent cannot be formed, so Equation (1) does not hold and the agent does not expand.
As can be seen from the mathematical expression, the expansion coefficient changes depending on 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 cleaving agent is 21 mN / m, and the interfacial tension is 0.2 mN / m, the expansion coefficient is 50.8 mN / m.
When the surface tension of the target liquid is 30 mN / m, the surface tension of the liquid film cleaving agent is 21 mN / m, and the interfacial tension is 0.2 mN / m, the expansion coefficient is 8.8 mN / m.
In any case, the larger the expansion coefficient, the greater the liquid film cleavage effect.
In this specification, the numerical value at the surface tension of 50 mN / m is defined. However, even if the surface tension is different, there is no change in the magnitude relationship between the numerical values of the expansion coefficients of the substances. Even if it changes with the physical condition of each day, the agent with a larger expansion coefficient shows an excellent liquid film cleavage effect.

The surface tension of the liquid film cleaving agent of the first embodiment 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. Moreover, the said surface tension is so good that it is small, and the minimum is not specifically limited. From the viewpoint of durability of the liquid film cleaving agent, 1 mN / m or more is practical.
By setting the surface tension of the liquid film cleaving agent to be in the above range or less, even when the surface tension of the target liquid that stretches the liquid film is lowered, the liquid film cleaving action can be effectively exhibited.

  Next, in the liquid film cleaving agent of the second embodiment, the “interfacial tension with respect to a liquid having a surface tension of 50 mN / m” is set to 20 mN / m or less, as described above. It means that the diffusibility in the above is increased. Thereby, even when the expansion coefficient is relatively small such that the “expansion coefficient for a liquid having a surface tension of 50 mN / m” is less than 15 mN / m, many liquid film cleaving agents are removed from the fiber surface due to high diffusibility. By dispersing in the liquid film and pushing the liquid film at many positions, the same effect as in the first embodiment can be achieved.

In the second embodiment, from the viewpoint of making the action of the liquid film cleaving agent more effective, the “interfacial tension with respect to a liquid having a surface tension of 50 mN / m” is preferably 17 mN / m or less, and 13 mN / m. The following is more preferable, 10 mN / m or less is further preferable, 9 mN / m or less is still more preferable, and 1 mN / m or less is particularly preferable. The lower limit is not particularly limited as in the first embodiment, and is practically larger than 0 mN / m from the viewpoint of not dissolving in a liquid film (a liquid having a surface tension of 50 mN / m). .
Further, the “expansion coefficient for a liquid having a surface tension of 50 mN / m” is preferably 9 mN / m or more, more preferably 10 mN / m or more from the viewpoint of making the action of the liquid film cleaving agent more effective. More preferably, it is 15 mN / m or more. Although the upper limit in particular is not restrict | limited, 50 mN / m or less is substantial from a viewpoint from which surface tension of the liquid which forms a liquid film becomes an upper limit from Numerical formula (1).
More preferable ranges of the surface tension and the water solubility of the liquid film cleaving agent are the same as those in the first embodiment.

  As described above, the liquid film cleaving agent of the first embodiment has the above expansion coefficient and water solubility, and the liquid film cleaving agent of the second embodiment has the above expansion coefficient, interfacial tension and water solubility. By this, it spreads without dissolving on the surface of the liquid film, and the liquid film layer can be pushed away from the vicinity of the center of the liquid film. As a result, the liquid film is destabilized and cleaved.

  It is preferable that the nonwoven fabric containing the liquid film cleaving agent of the first embodiment and the nonwoven fabric containing the liquid film cleaving agent of the second embodiment further contain a phosphate ester type anionic surfactant. This increases the hydrophilicity of the fiber surface and improves the wettability, thereby increasing the area where the liquid film and the liquid film cleaving agent are in contact. Since blood and urine have a surface-active substance having a phosphate group derived from a living body, when a surfactant having a phosphate group is used in combination with a liquid film cleaving agent, the surfactant is compatible with the liquid film cleaving agent. It has solubility and also has good affinity with phospholipids contained in blood and urine. Therefore, the liquid film cleaving agent easily moves to the liquid film, and the cleavage of the liquid film is further promoted. The content ratio of the liquid membrane cleaving agent to the phosphate ester type anionic surfactant is preferably 1: 1 to 19: 1 in terms of mass ratio (liquid membrane cleaving agent: phosphate ester type anionic surfactant), 2: 1 to 15: 1 is more preferable, and 3: 1 to 10: 1 is still more preferable. In particular, the content ratio is preferably 5: 1 to 19: 1, more preferably 8: 1 to 16: 1, and still more preferably 11: 1 to 13: 1 in terms of mass ratio.

  The phosphate ester type anionic surfactant is not particularly limited. For example, those described in paragraph [0031] of International Publication No. 2016/098796 can be used.

  Next, specific examples of the liquid film cleaving agent in the first embodiment and the second embodiment will be described. These are not soluble in water or have poor water-solubility because they are in the specific numerical range described above, and act to cleave the liquid film. On the other hand, surfactants used as conventional fiber treatment agents are practically water-soluble when used by dissolving in water, and are not the liquid film cleaving agent of the present invention. .

  The liquid film cleaving agent in the first embodiment and the second embodiment is preferably a compound having a mass average molecular weight of 500 or more. This mass average molecular weight greatly affects the viscosity of the liquid film cleaving agent. The liquid film cleaving agent keeps the viscosity high so that it does not easily flow off when the liquid passes between the fibers, and the liquid film cleaving effect in the nonwoven fabric can be maintained. From the viewpoint of achieving a viscosity that sufficiently maintains the liquid film cleavage effect, the mass average molecular weight of the liquid film cleavage agent is more preferably 1000 or more, further preferably 1500 or more, and particularly preferably 2000 or more. On the other hand, from the viewpoint of the transition of the liquid film cleaving agent from the fiber in which the liquid film cleaving agent is arranged to the liquid film, that is, a viscosity that maintains macro and micro diffusibility, 50000 or less is preferable, and 20000 or less is more preferable. 10,000 or less is more preferable. This mass average molecular weight is measured by the method described in paragraph [0035] of WO2016 / 098796.

  In addition, as the liquid film cleaving agent in the first embodiment, compounds described in paragraphs [0036] to [0039] of International Publication No. 2016/098796 are preferable.

Specific examples of the compound include organic surfactants (polysiloxanes) that are silicone surfactants. Examples thereof include those described in paragraph [0040] of International Publication No. 2016/098796.
Among them, a modified silicone having a structure in which a liquid film cleaving agent that is a modified silicone has at least one oxygen atom in a modified group, such as polyoxyalkylene-modified silicone, epoxy-modified silicone, carbinol-modified silicone, and diol-modified silicone is preferable. In particular, polyoxyalkylene-modified silicone is preferred. Since the polyoxyalkylene-modified silicone has a polysiloxane chain, it hardly penetrates into the inside of the fiber and tends to remain on the surface. In addition, the addition of a hydrophilic polyoxyalkylene chain is preferable because the affinity with water is increased and the interfacial tension is low, so that the movement on the surface of the liquid film is likely to occur. Therefore, it is preferable that the movement on the surface of the liquid film described above easily occurs. In addition, even if the polyoxyalkylene-modified silicone is subjected to hot melt processing such as embossing, it tends to remain on the fiber surface at that portion, and the liquid film cleavage action is difficult to reduce. In particular, the liquid film cleaving action is sufficiently exhibited at the embossed portion where the liquid tends to accumulate, which is preferable.

  Examples of the polyoxyalkylene-modified silicone include those described in paragraphs [0041] to [0049] of International Publication No. 2016/098796.

  As the liquid film cleaving agent in the second embodiment, compounds described in paragraphs [0050] to [0053] of International Publication No. 2016/098796 are preferable.

Further, specific examples of the compound include the following compounds, but are not limited thereto.
First, polyether compounds and nonionic surfactants can be mentioned. Specifically, a polyoxyalkylene alkyl (POA) ether represented by any one of the formula (V), a polyoxyalkylene glycol represented by the formula (VI) having a mass average molecular weight of 1000 or more, steareth, behenez, PPG Examples include myristyl ether, PPG stearyl ether, and PPG behenyl ether. The polyoxyalkylene alkyl ether is preferably lauryl ether to which POP is added in an amount of 3 mol to 24 mol, preferably 5 mol. As the polyether compound, polypropylene glycol having a weight average molecular weight of 1000 to 10,000, preferably 3000, to which polypropylene glycol is added in an amount of 17 to 180 mol, preferably about 50 mol, is preferable. In addition, the measurement of said mass mean molecular weight can be performed with the measuring method mentioned above.

  The polyether compound and the nonionic surfactant are preferably those described in paragraphs [0055] to [0059] of International Publication No. 2016/098796.

  Secondly, the hydrocarbon compounds described in paragraphs [0060] to [0086] of International Publication No. 2016/098796 are listed.

  In the nonwoven fabric according to the present invention, other components may be contained as necessary in addition to the liquid film cleaving agent described above. Further, the liquid film cleaving agent of the first embodiment and the liquid film cleaving agent of the second embodiment may be used in combination of both agents in addition to the forms used separately. This point is the same for the first compound and the second compound in the liquid film cleaving agent of the second embodiment.

  In the nonwoven fabric according to the present invention, the identification of the liquid film cleaving agent or phosphate ester type anionic surfactant contained therein, the component of the liquid film cleaving agent is a compound having a siloxane chain as the main chain, or 1 carbon atom The content ratio (OPU) of the liquid film cleaving agent with respect to the fiber mass in the case of the hydrocarbon compound of 20 or less can be measured by the method described in paragraph [0088] of WO2016 / 098796. .

  Since the nonwoven fabric according to the present embodiment has a high effect of reducing liquid residue and is excellent in dryness, it has excellent liquid permeability regardless of the thickness of the fibers and the distance between the fibers. From this, as described in paragraphs [0089] to [0092] of International Publication No. 2016/098796, the interfiber distance necessary for the liquid permeability of the nonwoven fabric can be made smaller than before. Thereby, it becomes possible to make the nonwoven fabric softer by using finer fibers than conventional ones.

  The form of the nonwoven fabric of this embodiment can be various. For example, it may be composed of one fiber layer or may be composed of two or more fiber layers. Moreover, a flat shape may be sufficient and it may have an uneven | corrugated shape. As a nonwoven fabric which has an uneven | corrugated shape, what was described in Paragraph [0100]-[0110] of the specification of international publication 2016/098796 and FIGS. 3-11 is mentioned, for example.

  The nonwoven fabric according to the present invention can be applied to various fields by taking advantage of the reduction of liquid residue, the prevention of liquid surface flow, and the high dryness. For example, a top sheet, a second sheet (a sheet disposed between the top sheet and the absorbent body) in an absorbent article used to absorb liquid discharged from the body such as sanitary napkins, panty liners, disposable diapers, and incontinence pads It is preferably used as an absorbent body, a covering sheet that wraps the absorbent body, a leak-proof sheet, or a personal wipe sheet, a skin care sheet, and an objective wiper. When using the nonwoven fabric which concerns on this invention as a surface sheet or a second sheet | seat of an absorbent article, it is good also considering which surface side of this nonwoven fabric as a skin opposing surface side. In the second embodiment, it is more preferable that the surface side where the fibers A are unevenly distributed is the skin facing surface side, and in the third embodiment, the surface side where the dense portions 74 of the fibers A are located is the skin facing surface side.

  An absorbent article used for absorbing liquid discharged from the body typically includes a top sheet, a back sheet, and a liquid-retaining absorbent body interposed between both sheets. As the absorbent body and the back sheet when the nonwoven fabric according to the present invention is used as a top sheet, materials usually used in the technical field can be used without particular limitation. For example, as the absorbent body, a fiber assembly made of a fiber material such as pulp fiber or a fiber assembly in which an absorbent polymer is held can be coated with a covering sheet such as tissue paper or nonwoven fabric. As the back sheet, a liquid-impermeable or water-repellent sheet such as a thermoplastic resin film or a laminate of the film and a nonwoven fabric can be used. The back sheet may have water vapor permeability. The absorbent article may further include various members according to specific uses of the absorbent article. Such members are known to those skilled in the art. For example, when applying an absorbent article to a disposable diaper or a sanitary napkin, a pair or two or more pairs of three-dimensional guards can be disposed on the left and right sides of the topsheet.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is limited to this and is not interpreted. In the examples, “part” and “%” are based on mass unless otherwise specified. The expansion coefficient, interfacial tension, surface tension, and water solubility were measured in the environmental region at a temperature of 25 ° C. and a relative humidity (RH) of 65% as described above. In the following Examples, the surface tension, water solubility, and interfacial tension of the liquid film cleaving agent were measured by the measurement methods described in paragraphs [0015] to [0022] of International Publication No. 2016/098796 described above. In the table below, “-” means that the agent indicated in the item name is not used, does not have a value corresponding to the item, and the like.

Example 1
(1) Production of fiber A Non-heat-shrinkable fiber, which is a core-sheath type composite fiber in which polyethylene terephthalate (PET) is a core and polyethylene (PE) is a sheath for the first fiber layer, and polypropylene for the second fiber layer A heat-shrinkable fiber, which is a side-by-side composite fiber composed of (PP) and polyethylene (PE), was prepared as a raw fiber for the fiber A. The fineness of the raw fiber for the first fiber layer was 1.2 dtex, and the fineness of the raw fiber for the second fiber layer was 2.3 dtex.
Moreover, the liquid film cleaving agent shown below was dissolved in ethanol, and the diluted solution of 1.7 mass% of active ingredients of a liquid film cleaving agent was produced.
Next, the diluted solution is applied by dipping the diluted solution to 10 g of each raw fiber for the first fiber layer, and dried at a centrifugal dehydrator 3260 rpm to prepare OPU 0.4 mass%. Thus, a fiber A for the first fiber layer was obtained. In the fiber A for the second fiber layer, 2.0% by mass of a solution obtained by dissolving a liquid film cleaving agent in ethanol is immersed in 10 g of fiber, deethanolated at 3260 rpm with a centrifugal dehydrator, and becomes 0.4% by mass of OPU. It was prepared as follows. The contact angles of the fibers A for the first fiber layer and the second fiber layer were measured by the method described above and were as shown in Table 1 below.
<Liquid film cleaving agent>
Polyoxyethylene (POE) modified dimethyl silicone (Shin-Etsu Chemical Co., Ltd. KF-6015), dimethyl silicone chain X in the structure X-Y consists _{O- -Si (CH 3) 2,} Y is - ( It consists of a POE chain consisting of C ₂ H ₄ O) —, the terminal group of the POE chain is a methyl group (CH ₃ ), the modification rate is 20%, the polyoxyethylene addition mole number is 3, and the mass average molecular weight is 4000. Compound.
The liquid film cleaving agent had a surface tension of 21.0 mN / m and a water solubility of less than 0.0001 g. The expansion coefficient of the liquid film cleaving agent for a liquid having a surface tension of 50 mN / m was 28.8 mN / m, and the interfacial tension for a liquid having a surface tension of 50 mN / m was 0.2 mN / m. . These numerical values were measured by the measurement method described above. At that time, “a liquid having a surface tension of 50 mN / m” is obtained by adding polyoxyethylene sorbitan monolaurate, which is a nonionic surfactant, to 100 g of deionized water (trade name: Leool Super TW-L120, manufactured by Kao Corporation). Was added with a micropipette (ACURA825, manufactured by Socorex Isba SA), and a solution having a surface tension adjusted to 50 ± 1 mN / m was used. The water solubility was measured by adding an agent every 0.0001 g. As a result, what was observed as not dissolving 0.0001 g was defined as “less than 0.0001 g”, 0.0001 g was dissolved, and 0.0002 g observed as not dissolved was defined as “0.0001 g”. The other numerical values were also measured by the same method.

(2) Production of fiber B Non-heat-shrinkable fiber, which is a core-sheath type composite fiber in which polyethylene terephthalate (PET) is a core and polyethylene (PE) is a sheath for the first fiber layer, and polypropylene for the second fiber layer A heat-shrinkable fiber, which is a side-by-side composite fiber made of (PP) and polyethylene (PE), was prepared as a raw material fiber for fiber B. The fineness of the raw fiber for the first fiber layer was 1.2 dtex, and the fineness of the raw fiber for the second fiber layer was 2.3 dtex.
Each raw material fiber was subjected to a hydrophilic treatment with a fiber treatment agent containing a nonionic surfactant, an anionic surfactant and the like, and fibers B for the first fiber layer and the second fiber layer were produced. All the fibers B were adjusted so as to be OPU 0.4 wt% of the fiber treatment agent. The contact angles of the fibers B for the first fiber layer and the second fiber layer were measured by the method described above and were as shown in Table 1 below.

(3) Preparation of nonwoven fabric sample of Example 1 Fiber A for the first fiber layer and fiber B for the first fiber layer were blended to prepare a fiber web for the first fiber layer. Moreover, the fiber A for 2nd fiber layers was mixed with the fiber A for 2nd fiber layers, and the fiber B for 2nd fiber layers, and the fiber web for 2nd fiber layers was produced. The fiber web for the first fiber layer contained 35% by mass of the fiber A, and the fiber web for the second fiber layer contained 35% by mass of the fiber A. The basis weight of each fiber web was 20 g / m ² . After laminating both fiber webs and fusing the fibers together by ultrasonic embossing, the fibers of the second fiber layer were made into a nonwoven fabric while being thermally shrunk by an air-through process, and a nonwoven fabric sample of Example 1 was produced. In addition, the content rate of said fiber A did not change even after making a fiber web into a nonwoven fabric, and was the same also in the following Examples etc.

(Example 2)
In any of the fiber web for the first fiber layer and the fiber web for the second fiber layer, the nonwoven fabric sample of Example 2 was prepared in the same manner as in Example 1 except that 17.5% by mass of fiber A was contained. Produced.

Example 3
A nonwoven fabric sample of Example 3 was prepared in the same manner as in Example 1 except that the fiber web for the first fiber layer and the fiber web for the second fiber layer each contained 40% by mass of fiber A. .

(Example 4)
A nonwoven fabric sample of Example 4 was produced in the same manner as in Example 1 except that the fiber web for the first fiber layer and the fiber web for the second fiber layer both contained 25% by mass of fiber A. .

(Example 5)
The same procedure as in Example 1 except that the fiber web for the first fiber layer contains 35% by mass of the fiber A, and the fiber web for the second fiber layer does not contain the fiber A and the fiber B is 100%. The nonwoven fabric sample of Example 4 was produced.

(Example 6)
A nonwoven fabric sample of Example 6 was produced in the same manner as in Example 1 except that the following was used as the liquid film cleaving agent.
<Liquid film cleaving agent>
Polyoxypropylene (POP) -modified dimethyl silicone (obtained by hydrosilylation reaction of silicone oil and hydrocarbon compound), and dimethyl silicone chain in which X in structure XY is —Si (CH ₃ ) ₂ O—, Y Is a POP chain composed of-(C ₃ H ₆ O)-, the terminal group of the POP chain is a methyl group (CH ₃ ), the modification rate is 20%, the polyoxypropylene addition mole number is 10, and the mass average molecular weight Is a compound of 7000.
The liquid film cleaving agent had a surface tension of 21.5 mN / m and a water solubility of less than 0.0001 g. The expansion coefficient of the liquid film cleaving agent for a liquid having a surface tension of 50 mN / m was 28.0 mN / m, and the interfacial tension for a liquid having a surface tension of 50 mN / m was 0.5 mN / m. .

(Example 7)
A nonwoven fabric sample of Example 7 was produced in the same manner as in Example 1 except that the following was used as the liquid film cleaving agent.
<Liquid film cleaving agent>
Polyoxypropylene (POP) alkyl ether (anti-foaming agent No. 8 manufactured by Kao Corporation), Z in structure ZY is a hydrocarbon chain comprising —CH ₂ —, Y is — (C ₃ H ₆ O) — A compound having a polyoxypropylene addition mole number of 5 and a mass average molecular weight of 500.
The liquid film cleaving agent had a surface tension of 30.4 mN / m and a water solubility of less than 0.0001 g. The expansion coefficient of the liquid film cleaving agent for a liquid having a surface tension of 50 mN / m was 13.7 mN / m, and the interfacial tension for a liquid having a surface tension of 50 mN / m was 5.9 mN / m. .

(Comparative example)
A nonwoven fabric sample of a comparative example was prepared in the same manner as in Example 1 except that the fiber A was not contained in any of the first fiber layer and the second fiber layer, and the fiber B was made of 100%.

(Reference Example 1)
In any of the fiber web for the first fiber layer and the fiber web for the second fiber layer, the nonwoven fabric sample of Reference Example 1 was prepared in the same manner as in Example 1 except that the fiber A was contained in 46.7% by mass. Produced.

(Reference Example 2)
Using the fibers B for the first fiber layer and the second fiber layer used in Example 1, a raw material nonwoven fabric made of a laminate of the first fiber layer and the second fiber layer was produced by an air-through treatment method. Subsequently, the liquid film cleaving agent used in Example 1 was applied from the first fiber layer side of the raw material nonwoven fabric to the raw material nonwoven fabric by a flexographic printing method, and a nonwoven fabric sample of Reference Example 2 was produced. In the nonwoven fabric sample, the content ratio (OPU) of the liquid film cleaving agent with respect to the fiber mass was set to 0.4 mass%.

(Test method)
(1) Liquid flow (run-off) length on the nonwoven fabric surface The test apparatus used was one having a placement portion where the placement surface of the test sample is inclined by 45 ° with respect to the horizontal plane. Each sanitary napkin sample was placed on the mounting portion with the nonwoven fabric sample facing upward. On the surface of each sanitary napkin sample, 0.5 g of simulated blood corresponding to menstrual blood (the same as that used in the measurement of “liquid remaining amount of nonwoven fabric sample” described later) at a rate of 0.1 g / second. It was dripped. The distance from the point where the liquid was first applied to the nonwoven fabric to the point where the simulated blood was drawn into the nonwoven fabric and stopped flowing was measured. In addition, the used horse blood was adjusted by the same method as the measurement of the liquid remaining amount of the following nonwoven fabric sample. The above operation was performed 3 times, and the average value of the 3 times was defined as the liquid flow length (mm). The liquid flow length is an index of how easily the liquid flows on the surface without being absorbed by the test sample and is likely to leak at the time of mounting. The shorter the liquid flow length, the higher the evaluation.

(2) Amount of liquid remaining in the nonwoven fabric sample An acrylic plate having a transmission hole with an inner diameter of 1 cm was placed on the surface of each sanitary napkin sample, and a constant load of 100 Pa was applied to the napkin. Under such a load, 6.0 g of pseudo blood corresponding to menstrual blood (adjusted equine defibrinated blood manufactured by Japan Biotest Laboratories Co., Ltd. to 8.0 cP) was poured into the acrylic plate from the permeation hole. The simulated blood used was adjusted with a TVB10 viscometer manufactured by Toki Sangyo under the condition of 30 rpm. When the horse blood is allowed to stand, a high-viscosity part (such as red blood cells) precipitates, and a low-viscosity part (plasma) remains as a supernatant. The mixing ratio of the part was adjusted to 8.0 cP. The acrylic plate is removed 60 seconds after a total of 6.0 g of simulated blood has been poured. Subsequently, the weight (W2) of the nonwoven fabric sample was measured, and the difference (W2−W1) from the weight (W1) of the nonwoven fabric sample before pouring horse blood, which had been measured in advance, was calculated. The above operation was performed 3 times, and the average value of the 3 times was defined as the remaining liquid amount (mg). The liquid remaining amount is an index of how much the wearer's skin gets wet. The smaller the liquid remaining amount, the better the result.

  The test results for the examples, comparative examples, and reference examples are shown in Table 1 below.

As shown in Table 1, in the comparative example not including the liquid film cleaving agent, the liquid remaining amount on the surface of the nonwoven fabric sample was 265 mg.
On the other hand, in Examples 1-7, the liquid residual amount of the nonwoven fabric sample which mixed the fiber A which has a liquid film cleaving agent, and the fiber B which has hydrophilic property is reduced to about 70% or less of the said comparative example. As a result, effective cleavage of the liquid film was confirmed. That is, Examples 1-7 had a high liquid residue reduction effect.
In addition, in Reference Example 1 consisting only of fiber A having a liquid film cleaving agent, and in Reference Example 2 in which a liquid film cleaving agent is contained on the entire surface of the nonwoven fabric, although the liquid residue is reduced, the liquid flow length on the nonwoven fabric surface However, there was room for improvement.
In contrast, in Examples 1 to 7, the liquid flow length was suppressed as compared with Reference Examples 1 and 2, and the liquid flow prevention property was higher than that of Reference Examples 1 and 2.
As described above, Examples 1 to 7 achieved both an improvement in liquid residue reduction and an improvement in liquid flow prevention.

DESCRIPTION OF SYMBOLS 1 Fiber 2 Liquid film 3 Liquid film cleaving agent 5, 6, 7 Nonwoven fabric 71 Concave 72 Convex part 73 Concave bottom part 74 Concentrated part of fiber A

Claims (6)

  A nonwoven fabric containing a fiber A having a liquid film cleaving agent and a hydrophilic fiber B, wherein the fiber A is contained in an amount of 40% by mass or less based on the nonwoven fabric.   A fiber A having a compound (C1) having an expansion coefficient of 15 mN / m or more and a water solubility of 0 g or more and 0.025 g or less with respect to a liquid having a surface tension of 50 mN / m, and a hydrophilic fiber B, A nonwoven fabric containing the fiber A in an amount of 40% by mass or less based on the nonwoven fabric.   A compound having an expansion coefficient greater than 0 mN / m for a liquid having a surface tension of 50 mN / m, a water solubility of 0 g or more and 0.025 g or less, and an interfacial tension for a liquid having a surface tension of 50 mN / m or less of 20 mN / m or less. A nonwoven fabric comprising a fiber A having (C2) and a fiber B having hydrophilicity, wherein the fiber A is contained in an amount of 40% by mass or less based on the nonwoven fabric.   The nonwoven fabric according to any one of claims 1 to 3, wherein the nonwoven fabric comprises a plurality of fiber layers, and the fibers A are unevenly distributed in the fiber layer on one surface side and are mixed with the fibers B.   The nonwoven fabric according to any one of claims 1 to 4, wherein the nonwoven fabric has a recess, and the fibers A are concentrated around the recess.   The absorbent article which used the nonwoven fabric of any one of Claims 1-5 as a surface sheet.

Images