TWI883165B - Nonwoven fabrics and absorbent articles - Google Patents

Abstract

The nonwoven fabric of the present invention has an adhesive and thermoplastic fibers, and has fusion points between the fibers. In the center of the thickness of the nonwoven fabric, there is a fiber intersection where fibers with thickness-direction components intersect with other fibers. The adhesive is present at the fiber intersection. The adhesive satisfies one or both of the following requirements (1) and (2).

(1) When viewing the nonwoven fabric from above, the area ratio of the adhesive per unit area is smaller than the area ratio of the fibers not covered by the adhesive.

(2) The ratio of the mass of the above-mentioned adhesive to the mass of the above-mentioned nonwoven fabric is at least 65 percentage points less than the ratio of the mass of the fiber to the mass of the above-mentioned nonwoven fabric.

Description

Nonwoven fabrics and absorbent articles

The present invention relates to a nonwoven fabric.

Nonwoven fabrics are used in various situations, and there are a large number of products using nonwoven fabrics. Technologies have been developed to give nonwoven fabrics various functions.

For example, Patent Document 1 states that, based on the viewpoint of improving the thickness recovery of absorbent articles such as diapers, a resin bonded nonwoven fabric impregnated or coated with a bonding agent is incorporated into the absorbent article. Specifically, the resin bonded nonwoven fabric is configured as a component of the absorbent article that does not come into contact with the skin.

On the other hand, from the perspective of improving the softness of the skin touch, the components of absorbent articles that come into contact with the skin usually use thermally bonded nonwoven fabrics including hot air nonwoven fabrics. Among them, hot air nonwoven fabrics are made by blowing hot air on the fiber web to fuse the fiber intersections. The basis weight of the obtained nonwoven fabric is suppressed and it is relatively fluffy.

Regarding the above-mentioned hot air nonwoven fabric, patent documents 2 to 4 describe a kind of concave-convex nonwoven fabric, which is a nonwoven fabric formed by pre-forming a fiber web into a concave-convex shape, thereby improving the compression deformation and cushioning properties, etc.

[Prior Art Literature] [Patent Literature]

[Patent document 1] Japanese Patent Publication No. 2001-187088

[Patent Document 2] Japanese Patent Publication No. 2012-136791

[Patent Document 3] Japanese Patent Publication No. 2019-44319

[Patent Document 4] Japanese Patent Publication No. 2019-44320

The present invention provides a non-woven fabric having an adhesive and thermoplastic fibers, and having fusion points between the fibers.

The nonwoven fabric is preferably such that there is a fiber intersection where fibers having thickness direction components intersect with other fibers at the center of the thickness of the nonwoven fabric, and the adhesive is present at the fiber intersection.

The above-mentioned adhesive preferably satisfies one or both of the following requirements (1) and (2).

(1) When viewing the nonwoven fabric from above, the area ratio of the adhesive per unit area is smaller than the area ratio of the fibers not covered by the adhesive.

(2) The ratio of the mass of the above-mentioned adhesive to the mass of the above-mentioned nonwoven fabric is at least 65 percentage points less than the ratio of the mass of the fiber to the mass of the above-mentioned nonwoven fabric.

The above and other features and advantages of the present invention may be more clearly understood by referring to the attached drawings, the scope of the patent application and the following description.

1A: Page 1

1B: Side 2

6: Fiber intersection

7: Fiber

8: Adhesive

10,20,30,40,50,60,70,80,90: nonwoven fabric

11: Upper level

12: Lower level

13,23,33,41,42,51,61,71,931:convex part

14,24,34,43,44,52,62,72,88,89,936: concave part

15,25,35,45,55,64,73,83,931W: Wall

20A: No. 1 nonwoven fabric

20B: 2nd nonwoven fabric

21: Hollow part

22: Joint

31: Upper level

32: Lower level

53: concave part

54:convex part

63: Bottom of concave part

81,82: Outer surface fiber layer

81A: 1st outer surface fiber layer

81B: Second outer surface fiber layer

83A: 1st connection

83B: Second connection part

100:Nonwoven fabric

100S: Non-woven fabric

100W: Non-woven fabric

105: Thickness center

120: Supporting public materials

121: protrusion

122: concave part

130: Support body base material

131: protrusion

200: Base material

911: Vertical embankment

911W: Wall

921: Horizontal embankment

922: concave part

934:convex part

935: Recess

C: Reference circle

F: Compression force

L: Baseline

L1: Top

L2: Below

L3: Left

L4: Right

Figure 1 (A) schematically shows the state of applying compressive force to nonwoven fabric, (B) schematically shows the state of releasing the compressive force, and (C) shows the state of three-dimensionally crossing fibers being repeatedly flattened and restored by compressive force at the fiber intersection.

FIG2 is a diagram showing one of the front and back surfaces of the nonwoven fabric when viewed from above, and also shows a portion of the observation image used in the method for determining the presence rate of the adhesive at the fiber intersection and a schematic diagram of the reference circle.

Figure 3 (A) is a side view showing the position of a section A (line A-A) cut through the center of the thickness of a flat nonwoven fabric and orthogonal to the fiber layer forming the nonwoven fabric surface (plane), and (B) is a side view showing the position of a section B (line B-B) cut through the center of the thickness and orthogonal to the above section A.

Figure 4 (A) is a side view showing the position of section A (line A-A) cut through the center of the thickness of the nonwoven fabric with a concave-convex shape and perpendicular to the fiber layer forming the nonwoven surface (the surface of the wall connecting the top of the convex part and the bottom of the concave part), and (B) is a side view showing the position of section B (line B-B) cut through the center of the thickness and perpendicular to the above section A.

FIG5 is a schematic diagram showing a portion of the observation screen and a square reference line used in the method for measuring the longitudinal orientation of nonwoven fabrics.

Figure 6 is a cross-sectional view schematically showing a specific example 1 of the concave-convex shape of a nonwoven fabric.

Figure 7 is a partial cross-sectional perspective view schematically showing a specific example 2 of the concave-convex shape of a nonwoven fabric.

Figure 8 is a partial cross-sectional perspective view schematically showing a specific example 3 of the concave-convex shape of a nonwoven fabric.

Figure 9 is a partial cross-sectional perspective view schematically showing a specific example 4 of the concave-convex shape of a nonwoven fabric.

Figure 10 is a partial cross-sectional perspective view schematically showing a specific example 5 of the concave-convex shape of a nonwoven fabric.

Figure 11 is a partial cross-sectional perspective view schematically showing a specific example 6 of the concave-convex shape of a nonwoven fabric.

Figure 12 is a partial cross-sectional perspective view schematically showing a specific example 7 of the concave-convex shape of a nonwoven fabric.

Figure 13 is a partial cross-sectional perspective view schematically showing a specific example 8 of the concave-convex shape of a nonwoven fabric.

FIG. 14 is a diagrammatic substitute photograph showing a plane of one side of a specific example 9 of the concave-convex shape of a nonwoven fabric.

Figures 15 (A) and (B) are partial cross-sectional views of the nonwoven fabric shown in Figure 14 along the C-C line.

Figure 16 is a partial cross-sectional view of the nonwoven fabric shown in Figure 14 along the D-D line.

FIG. 17 is a schematic substitute photograph showing a plane on the opposite side of the nonwoven fabric shown in FIG. 14 .

Figure 18 is a partial cross-sectional view of the nonwoven fabric shown in Figure 17 along the E-E line.

Figure 19 is a partial cross-sectional view of the nonwoven fabric along the F-F line shown in Figure 17.

FIG. 20 schematically illustrates the manufacturing steps of the nonwoven fabric sample in Example 5. (A) illustrates the step of placing a fiber net on a support male material and pressing a support mother material from the fiber net into the support male material. (B) illustrates the step of blowing a first hot air from above the support mother material to shape the fiber net. (C) illustrates the step of removing the support mother material and blowing a second hot air from above the shaped fiber net to fuse the fibers.

The present invention relates to a nonwoven fabric with excellent texture and excellent thickness recovery.

For example, even if the thermally bonded nonwoven fabric is subjected to compression pressure when assembled into a product and sealed in a packaging bag, its thickness will be restored due to its cushioning property when it is taken out of the packaging bag.

However, its thickness recovery is not sufficient compared to the thickness before sealing, and there is still room for improvement. In this regard, the resin bonded nonwoven fabric described in Patent Document 1 is formed by impregnating or coating the entire fiber aggregate with an adhesive, so the manufacturing method is different from that of thermal bonded nonwoven fabric. In terms of skin touch, thermal bonded nonwoven fabric is more superior. Therefore, the resin bonded nonwoven fabric described in Patent Document 1 cannot be directly applied to the use of thermal bonded nonwoven fabric.

In contrast, the nonwoven fabric of the present invention has excellent texture and thickness recovery.

The following describes the preferred implementation of the nonwoven fabric of the present invention.

The nonwoven fabric of the present invention has an adhesive and thermoplastic fibers, and has a fusion point between the fibers. The fusion point is a portion where the fibers are bonded to each other without the presence of the adhesive at the junction between the crossed fibers. More specifically, the fusion point is formed by partially melting the surface of the thermoplastic fibers by heat treatment during the manufacturing process of the nonwoven fabric, and the fibers are bonded to each other by the melting. The nonwoven fabric of the present invention uses, for example, hot air nonwoven fabric.

The nonwoven fabric of the present invention has fiber intersections where fibers having thickness direction components of the nonwoven fabric intersect with other fibers. Adhesive is present at the fiber intersections. The fiber intersections refer to the portions where two or more fibers intersect.

The adhesive present at the fiber intersection preferably covers the outer surface of the portion where the fibers cross and overlap each other. In addition, the adhesive preferably exists at the fiber intersection and extends to the fiber surface outside the fiber intersection.

The above-mentioned adhesive is a resin component different from the constituent fibers of the nonwoven fabric, and is fixed to the surface of the constituent fibers of the nonwoven fabric. For example, the adhesive can be sprayed on one side of the nonwoven fabric by a sprayer and fixed to the intersection of the fibers. From the perspective of suppressing the sticky feeling when in contact with the skin, it is better to spray the adhesive from the side of the nonwoven fabric opposite to the side in contact with the skin.

Based on the same viewpoint, the spraying mass of the adhesive is preferably less than 5 g/ ^m2 per unit area of the nonwoven fabric.

In addition, from the perspective of effectively demonstrating the effect of the adhesive on the fiber intersections, the sprayed mass of the adhesive is preferably 0.3 g/ ^m2 or more per unit area of the non-woven fabric.

The nonwoven fabric of the present invention has one side and an opposite side. In this specification, the one side is sometimes referred to as the first side and is labeled with 1A. The opposite side is sometimes referred to as the second side and is labeled with 1B. In the nonwoven fabric of this embodiment, the reverse side (second side) is the side that does not contact the skin during use (non-skin side).

The above-mentioned "one side" and "back side" refer to the front and back sides of the non-woven fabric, which are the side farthest from the horizontal plane and the side closest to the horizontal plane in the direction perpendicular to the horizontal plane when the non-woven fabric is placed on the horizontal plane.

In this embodiment, the opposite side is the side on which the adhesive is sprayed.

The fixed adhesive has the adhesive property of being fixed to the surface of the fiber intersection without flowing off. In addition, the adhesive has the strength to withstand the fiber activity at the fiber intersection required for the cushioning of the nonwoven fabric, and on the other hand, has the elasticity to restore the positional relationship between the fibers after the activity to the original state. Furthermore, based on the viewpoint of exerting the above-mentioned effects, it is preferred that the elastic strain of the adhesive is greater than that of the fiber.

The above-mentioned adhesive acts on the fiber intersections, for example, in the following manner.

As shown in Fig. 1 (A) and (B), a compressive force (pressing force) F is applied to one side 1A of the nonwoven fabric 100, and then the compressive force F is released. At this time, the three-dimensional cross arrangement of the fibers 7 at the fiber intersection 6 in the nonwoven fabric 100 is flattened by the compressive force F. However, when the pressing force F is released, the three-dimensional cross arrangement of the fibers 7 at the fiber intersection 6 is restored by the adhesive 8 (Fig. 1 (C)). In addition to the compression generated by the human body, when the product is sealed in a packaging bag and subjected to compressive pressure, the three-dimensional cross arrangement of the fibers 7 at the fiber intersection 6 is restored by the adhesive 8 when the product is taken out of the packaging bag. Furthermore, FIG. 1(A) and (B) show a state where the nonwoven fabric 100 is placed on the substrate 200, but the present invention is not limited to this state.

The above-mentioned "fibers having a thickness direction component of the nonwoven fabric" refers to fibers having a vertical direction component as a vector relative to the horizontal plane when the nonwoven fabric of the present invention is placed on a horizontal plane with one of the front and back sides facing upward. "Other fibers" refers to fibers other than a "fiber having a thickness direction component of the nonwoven fabric" when focusing on it. "Having a thickness direction component" means that the vertical direction component exceeds zero.

(Method for confirming the presence of fibers with thickness direction components of non-woven fabrics and method for confirming the presence of adhesives)

Fibers with thickness direction components of nonwoven fabrics can be confirmed by the same method as (6a) and (6b) in the following (Method for determining longitudinal orientation of nonwoven fabrics).

In addition, the presence or absence of adhesive in the fibers having the thickness direction component of the nonwoven fabric can be confirmed by the same method as the following (Method for determining the presence ratio of adhesive at the intersection of fibers in the thickness center of the nonwoven fabric).

Furthermore, when the nonwoven fabric to be measured has been incorporated into products such as absorbent articles, the bonding force of the adhesive is weakened by cooling methods such as cold spraying, and the nonwoven fabric is removed from the product for the above treatment. The nonwoven fabric removal method is also applicable to other measurements in this manual.

Regarding fibers with thickness direction components of nonwoven fabrics, according to (4a) to (4c) of the following (Method for determining the presence rate of adhesive at fiber intersections in the thickness center of nonwoven fabrics), when there are dyed fiber intersections in the thickness center, it means that adhesive exists at "the fiber intersections where the fibers with thickness direction components in the thickness center of the nonwoven fabric intersect with other fibers."

The nonwoven fabric of the present invention has the following function, that is, even if the direction of "fibers having thickness direction components of the nonwoven fabric" changes due to compression force, the positional relationship (three-dimensional cross configuration) between "fibers having thickness direction components of the nonwoven fabric" and other fibers can be restored at the position of the fiber intersection where the above-mentioned adhesive exists. In this way, the orientation direction of "fibers having thickness direction components of the nonwoven fabric" is easy to restore, and as a result, the thickness recovery of the nonwoven fabric is excellent. The thickness recovery is evaluated by the compression recovery rate. The larger the value of the compression recovery rate, the better the thickness recovery.

Based on this viewpoint, the above-mentioned adhesive is preferably present at multiple fiber intersections of "fibers having thickness direction components of non-woven fabrics".

The above-mentioned "thickness center" refers to the portion located at 50% of the distance in the vertical direction relative to the horizontal plane between the horizontal plane and the imaginary plane, and the imaginary plane is in contact with the outermost part of the side opposite to the surface of the nonwoven fabric in contact with the horizontal plane (hereinafter, the vertical direction relative to the horizontal plane is sometimes referred to as the "vertical direction").

The distance between the horizontal plane and the imaginary plane in the vertical direction is also called the apparent thickness of the nonwoven fabric. For example, when the nonwoven fabric of the present invention has concave-convex shapes on both sides, the apparent thickness is the distance in the vertical direction between the position of the top of the convex part on one side and the position of the top of the convex part on the other side.

The apparent thickness of nonwoven fabrics can be measured under a load of 50Pa by the following measurement method. Here, the 50Pa load refers to the load that can suppress the fuzzing of the surface of the nonwoven fabric, and is the load required to accurately measure the apparent thickness of the nonwoven fabric.

(Method for measuring apparent thickness of nonwoven fabrics under 50Pa load)

Cut the nonwoven fabric to be measured into 10cm×10cm to prepare a test sample. Use a laser thickness gauge (manufactured by Omron Co., Ltd., high-precision displacement sensor ZS-LD80 (trade name), the laser thickness gauges used in this case manual are all this product) to measure the thickness of the above test sample under a load of 50Pa. Measure 3 points and take the average value as the apparent thickness of the nonwoven fabric to be measured. For example, a round plate with a diameter of 2.5cm and a mass of 2.45g is placed on the nonwoven fabric to apply a load of 50Pa to the nonwoven fabric.

Furthermore, when the nonwoven fabric to be measured has been incorporated into a product, the bonding force of the adhesive is weakened by a cooling method such as cold spraying, and the nonwoven fabric is removed from the product for the above-mentioned measurement. The nonwoven fabric removal method is also applicable to other measurements in this manual.

If it is not possible to take out a non-woven fabric of 10cm×10cm size as the measurement object, take out the largest possible size.

The thickness of the nonwoven fabric here is measured by the following method. That is, the nonwoven fabric to be measured is cut into 10×10cm, and the thickness is measured at a load of 50Pa using a laser thickness gauge (manufactured by Omron Co., Ltd., high-precision displacement sensor ZS-LD80 (trade name)). Measure 3 locations and take the average value as the thickness of the nonwoven fabric (this thickness measurement is also applicable to other measurements). When the nonwoven fabric to be measured cannot be cut into 10×10cm, the cutting size should be as large as possible.

In the nonwoven fabric of the present invention, based on the viewpoint of obtaining flexible deformation when pressed, the apparent thickness of the nonwoven fabric under a load of 50Pa is preferably 1.3mm or more, more preferably 1.5mm or more, further preferably 2.0mm or more, further preferably 3.0mm or more, further preferably 4.5mm or more, further preferably 5.5mm or more. Moreover, based on the same viewpoint, the above apparent thickness is preferably 15mm or less, more preferably 10mm or less, further preferably 9mm or less, further preferably 8.5mm or less.

In the nonwoven fabric of the present invention, from the viewpoint of obtaining flexible deformation during pressing, the basis weight is preferably 10 g/m ² or more, more preferably 15 g/m ² or more, further preferably 20 g/m ² or more, further preferably 25 g/m ² or more. Moreover, from the same viewpoint, the basis weight is preferably 60 g/m ² or less, more preferably 55 g/m ² or less, further preferably 50 g/m ² or less, further preferably 48 g/m ² or less.

As long as the above-mentioned adhesive exists at "the fiber intersection where the fibers with thickness direction components intersect with other fibers in the thickness center of the non-woven fabric", it may also exist at other fiber intersections.

If the above adhesive exists in the intersection of fibers that have not yet been fused, it will be flexible and deformable when pressed, and can restore the positional relationship (three-dimensional intersection relationship) between the fibers.

If the above-mentioned adhesive exists at the fusion point between the fibers, the positional relationship (three-dimensional cross relationship) between the fixed fibers can be maintained more firmly.

Based on the viewpoint of achieving both thickness recovery and soft cushioning of nonwoven fabric, it is preferable that the above-mentioned adhesive exists at both the fusion points between the fibers and the intersections between the fibers that have not yet been fused. In this case, the number of "fiber intersections where the fibers oriented in the thickness direction intersect with other fibers" for the adhesive to exist is preferably the number of fused fiber intersections > the number of unfused fiber intersections.

In the nonwoven fabric of the present invention, the above-mentioned adhesive preferably satisfies one or both of the following requirements (1) and (2).

(1) When viewing the nonwoven fabric from above, the area ratio of the adhesive per unit area is smaller than the area ratio of the fibers not covered by the adhesive.

(2) The ratio of the mass of the above-mentioned adhesive to the mass of the above-mentioned nonwoven fabric is at least 65 percentage points less than the ratio of the mass of the fiber to the mass of the above-mentioned nonwoven fabric.

The area ratio and mass ratio of the above-mentioned adhesive specified in the above requirements (1) and (2) are not limited to the adhesive existing at "the intersection of fibers where fibers with thickness direction components intersect with other fibers", but indicate the value of the adhesive contained in the nonwoven fabric. For example, it includes the adhesive existing at "the intersection of fibers other than 'fibers with thickness direction components'", the adhesive existing on the fiber surface rather than at the fiber intersection, and the adhesive existing in the space between fibers.

In addition, the fiber area ratio and fiber mass specified in the above requirements (1) and (2) refer to the area ratio and mass in the state where there is no adhesive on the fiber (the fiber surface is not covered by the adhesive) (the other matters described below have the same meaning).

Thus, in the nonwoven fabric of the present invention, the effect of the above-mentioned adhesive can be effectively presented, and the amount of the adhesive can be appropriately suppressed, thereby suppressing the stickiness of the nonwoven fabric when it contacts the skin and the hardening of the nonwoven fabric as a whole. That is, the heat-bonded nonwoven fabric can maintain a characteristic soft skin touch. The adhesive has adhesiveness, so a small amount of adhesive can exert the above-mentioned effect. Therefore, the adhesive is preferably present at the fusion point between the fibers. Since the bonded intersection is formed at the fusion point, it is not necessary to form the intersection formed by the adhesive for fixing the fibers to each other.

In this way, the thickness recovery effect brought about by the elasticity of the adhesive can be prevented from being reduced due to the adhesiveness of the adhesive by appropriately suppressing the amount of adhesive fixed. In particular, the adhesive can be suppressed from sticking the fibers to each other at parts other than the intersection of the fibers, thereby effectively demonstrating the above-mentioned effect of the adhesive.

By making the adhesive presence area ratio per unit area of the nonwoven fabric smaller than the fiber area ratio, the contact between adhesives can be suppressed. In this way, the influence of adhesiveness caused by the contact between adhesives can be suppressed, so that the elastic effect of the adhesive under the contact between fiber and adhesive can be more effectively presented. As a result, the above-mentioned effect of the adhesive can be effectively presented.

Furthermore, by making the mass ratio of the adhesive less than the mass ratio of the fiber by more than 65 percentage points, the amount of adhesive can be reduced so that there is no adhesive between the fibers. As a result, the adhesive condenses at the fiber intersections with higher capillary force and can selectively adhere to the fiber intersections that play a role in recovery.

As a result, the nonwoven fabric of the present invention has excellent thickness recovery after compression and maintains a soft texture.

For example, even if the nonwoven fabric of the present invention is incorporated as the surface sheet of an absorbent article such as a diaper and the absorbent article is folded and sealed in a packaging bag, the fluffy feeling and soft texture of the nonwoven fabric of the present invention can be truly felt when the bag is taken out after opening.

The above requirements (1) and (2) can be measured by the following method. Furthermore, it is assumed that as the most common component used for nonwoven fabric raw materials, a treatment agent such as an oil, a skin care agent or a hot melt adhesive is used, and as a fiber composition, polyethylene terephthalate, polyethylene, and polypropylene are used. The solvent or conditions can be appropriately adjusted according to the components.

(Measurement method for requirement (1))

(1a) Prepare 0.3g of nonwoven fabric sample as the test sample. Then, place the nonwoven fabric sample in a beaker containing 100mL of ethyl acetate, stir for 30 minutes, take out the nonwoven fabric sample and dry it. In this way, the components such as skin care products and hot melt adhesives attached to the nonwoven fabric sample are washed away.

(1b) Use an identification reagent (fiber identification reagent Bokenstain II, manufactured by the Textile Quality Evaluation Institute) to dye the non-woven fabric sample. The identification reagent dyes the adhesive fixed on the fiber surface into a color different from the fiber to identify both the fiber and the adhesive.

(1c) Place the nonwoven sample on a horizontal surface and use a digital microscope VHX-900 (trade name, manufactured by Keyence Co., Ltd., all digital microscopes in this manual refer to this product) to take an observation image at 100 times magnification. In addition, turn the nonwoven sample over to expose the back side and take the image in the same way. The image taken is used as the observation image. The size of the observation screen is 2.5mm in the vertical direction and 3.0mm in the horizontal direction.

(1d) The observed images of one side and the opposite side are processed into three-values. Based on the colors after the three-value conversion, the fiber area not covered by the adhesive, the adhesive area, and other areas (such as the gaps between fibers) are identified. Based on this, the area of the adhesive and the area of the fiber not covered by the adhesive are calculated. The side with the larger area of the adhesive (one of the front and back sides of the nonwoven sample or the opposite side) is used as the measurement surface. Considering the size relationship of the unit area, calculate the adhesive presence area ratio and the fiber area ratio not covered by the adhesive when the area of the adhesive and the fiber area not covered by the adhesive are added to 100. In the same sample, perform the above measurement at 3 points on the above measurement surface, take the average value, and use the average value as the measurement value data. Based on the average measurement value, compare the adhesive presence area ratio and the fiber area ratio not covered by the adhesive to determine whether the above requirement (1) is met.

Explain the dyeing process in (1b) above.

(1b-1) Shake the container of Bokenstain II vigorously to mix it thoroughly.

(1b-2) Take 1.5mL of the mixed Bokenstain II and put it into a beaker of about 200mL. Add deionized water to make the total volume reach 30mL. This is how to make the dye solution.

(1b-3) Heat the dye solution until it reaches about 90°C before boiling, then add the nonwoven sample and boil it at 95°C for 2 minutes.

(1b-4) Take out the nonwoven fabric sample, wash it thoroughly with water, and then dry it.

(1b-5) Determination is made by comparing with the identification color. For example, an adhesive containing acrylic resin or styrene butadiene rubber is dyed red, and the fiber remains white. However, the color of the dyed adhesive varies depending on the adhesive ingredients.

The following is a specific example of the calculation process of (1d) above. In this specific example, the fiber identification reagent Bokenstain II is used to dye the adhesive area containing acrylic resin or styrene butadiene rubber red, the fiber area remains white, and other areas outside the adhesive area and fiber area (such as the gaps between fibers) become black.

(1d-1) The observed image is processed into three values (white, red, and black). This processing is performed by image processing in a computer, and the red area and white area in the RGB color model can be calculated.

(1d-2) Convert from RBG color mode to HSV color mode. In HSV color mode, Red is defined as H: 0° to 90° and 270° to 360°, S: 30% to 100%, V: 40% to 100%. White is defined as H: 0° to 360°, S: 0% to 20%, V: 40% to 100%. Black is defined as the range other than the above.

(1d-3) In this way, the red area (adhesive) and white area (fiber) are calculated in the HVS color model, and the above (d) processing is performed.

Regarding the amount of adhesive in the nonwoven fabric of the present invention, it is preferred that the amount of adhesive is greater on the opposite side (the second side) than on one side (the first side) of the front and back sides. It is preferred that the above-mentioned requirement (1) is satisfied on the opposite side.

For example, when an adhesive is sprayed on one side of a nonwoven fabric and spread throughout the thickness direction, the amount of adhesive adhered to the sprayed side increases.

Based on this, in the above (measurement method of requirement (1)), the "side with a larger adhesive area ratio" can be used as the measurement side to grasp the tendency of the fixing amount of the nonwoven fabric as a whole. In addition, the observation image of the measurement side not only captures the photographed surface, but also captures the thickness inside that can be observed from the surface (the range of focus in the observation image becomes the measurement object). Furthermore, these matters are also applicable to the situation in which the observation image is obtained and measured by other measurement methods (1a)~(1c) above.

Thus, in the above-mentioned (measurement method of requirement (1)), not only the surface of the nonwoven fabric but also the adhesive area inside the thickness can be captured, and the adhesive fixation amount in the nonwoven fabric can be grasped as a relative area ratio when compared with the fiber.

The adhesive is elastic and sticky at the same time. Therefore, by spraying the adhesive on one side of the non-woven fabric, the non-sprayed surface can achieve both a smooth texture without stickiness and a soft texture with resilience.

Regarding the above requirement (1), from the perspective of more effectively presenting its elasticity than the adhesiveness of the adhesive, the difference (M2-M1) between the area ratio (M1) of the adhesive present per unit area and the area ratio (M2) of the fiber not covered by the adhesive is preferably 80 percentage points or more, more preferably 90 percentage points or more, and even more preferably 99 percentage points or more.

Furthermore, from the perspective of presenting the elastic effect of the adhesive, the above difference (M2-M1) is preferably less than 99.99 percentage points, more preferably less than 99.95 percentage points, and further preferably less than 99.9 percentage points.

(Measurement method for requirement (2))

(2a) Prepare a total of 1.0 g of nonwoven fabric samples that have been subjected to the same treatment as in (1a) above (Measurement method for requirement (1)).

(2b) Cut the nonwoven fabric sample into 0.1 mm square pieces. Put 1.0 g of the sample into a beaker, add hexafluoroisopropyl alcohol (hereinafter referred to as HFIP), and separate it into HFIP insoluble and HFIP soluble. In this way, the polyethylene terephthalate (hereinafter referred to as PET) component of the fiber is dissolved.

(2c) Add heated xylene (130°C) to the HFIP insoluble fraction obtained in (2b) above, stir thoroughly and filter to separate into heated xylene insoluble fraction and heated xylene soluble fraction. In this way, the polypropylene (hereinafter referred to as PP) component and polyethylene (hereinafter referred to as PE) component of the fiber are dissolved.

(2d) The maximum weight of the HFIP insoluble matter obtained in (2c) above is measured by heating the xylene insoluble matter, and TG/DTA measurement is performed. The amount burned in the TG/DTA measurement is defined as the mass of the adhesive (the fiber may also contain additives such as titanium oxide. If the fiber contains titanium oxide, the adhesive can be separated from the titanium oxide).

(2e) Divide the mass of the adhesive obtained in (2d) above by 1.0g of the nonwoven fabric sample prepared in (2a) above to calculate the mass ratio (%) of the adhesive. Also, divide the maximum weighed weight of the HFIP insoluble matter and the heated xylene insoluble matter obtained in (2d) above by 1.0g of the nonwoven fabric sample prepared in (2a) above to calculate the mass ratio (%) of the fiber. Determine whether the above requirement (2) is met based on the difference between the mass ratio (%) of the adhesive and the mass ratio (%) of the fiber.

In the above (measurement method of requirement (2)), the amount of adhesive contained in the nonwoven fabric as a whole can be measured as the mass ratio of the nonwoven fabric to the mass of the fiber as a relative relationship when compared with the fiber.

This can eliminate the effects of skin care agents, hot melts, oils, etc. that may be included in the weight of nonwoven fabrics, and understand the relationship between fibers and adhesives.

Regarding the requirement (2) above, from the viewpoint of more effectively preventing the nonwoven fabric from becoming sticky or hardening as a whole, the ratio of the mass of the adhesive to the mass of the nonwoven fabric (W1) is preferably 78 percentage points or more lower than the ratio of the mass of the fiber to the mass of the nonwoven fabric (W2), and further preferably 81 percentage points or more lower.

Furthermore, from the perspective of showing the elastic effect of the adhesive, the difference (W2-W1) is preferably less than 90 percentage points, and more preferably less than 85 percentage points.

In the nonwoven fabric of the present invention, it is preferred that the presence rate of the above-mentioned adhesive on the fiber intersections on at least one side of the front and back of the nonwoven fabric when viewed from above is 5% or more and 60% or less per unit area of the nonwoven fabric. Thus, the presence of an appropriate amount of adhesive at the fiber intersections of the nonwoven fabric can suppress the adhesion of the fibers to each other caused by the adhesive, and facilitate the smoother recovery of the three-dimensional cross configuration of the fibers at the fiber intersections. In addition, the thickness recovery under the action of the above-mentioned adhesive can be achieved, and the sticky feeling of the nonwoven fabric can be suppressed.

From the perspective of improving the above-mentioned effects, the presence rate of the above-mentioned adhesive at the fiber intersections on at least one side of the front and back of the nonwoven fabric when viewed from above is preferably 10% or more, and further preferably 20% or more, based on the unit area of the nonwoven fabric.

From the perspective of more effectively presenting its elasticity than the adhesiveness of the adhesive, the presence rate of the above-mentioned adhesive at the fiber intersection on at least one side of the front and back of the non-woven fabric when viewed from above is preferably less than 50%, and more preferably less than 35% per unit area of the non-woven fabric.

Furthermore, any of the front and back sides is preferably the second side. Here, the second side is the side that does not contact the skin (non-skin side) when used as described above.

Furthermore, among the above-mentioned fiber intersections, there are intersections that have not yet been fused with the fusion points between the fibers. The fiber intersections in the above-mentioned percentage of the adhesive at the fiber intersections are preferably fusion points. The percentage of the adhesive at the fusion points is preferably within the above-mentioned numerical range. In this way, compared with the case where the adhesive itself bonds the fibers to each other, the amount of adhesive can be greatly reduced, and as a result, the formation of a film between the fibers can be suppressed, the sticky feeling can be reduced, and the thickness recovery can be more easily exhibited. Furthermore, among the following various "percentages of the adhesive at the fiber intersections", based on the same reasons as above, the fiber intersections are preferably fusion points. Furthermore, the existence rate of the adhesive at the fusion point is preferably within the range of values shown in the following "existence rate of the adhesive at the fiber intersection point".

(Method for determining the presence rate of adhesive at the intersection of fibers on either the front or back side of a nonwoven fabric when viewed from above)

(3a) Carry out the processing of (1a), (1b) and (1c) of the above (measurement method of requirement (1)).

(3b) A reference circle C with a diameter of 1.0 mm (size in the observation image) is marked in the observation image on each side of the front and back of the nonwoven sample. The number of fiber intersections (N) within the reference circle C and the number of fiber intersections (Nb) that have been dyed are counted. The side with a larger number of fiber intersections (Nb) is used as the measurement side. Furthermore, the range of the focus in the observation image becomes the measurement object. The count of fiber intersections includes both fibers that have been fused to each other and those that have not been fused.

(3c) Based on the following formula (S1), calculate the existence rate of adhesive per unit area at the fiber intersection.

H(%)=Nb÷N×100 (S1)

H: The presence rate of adhesive per unit area at the fiber intersection

Nb: The number of intersection points of dyed fibers within the reference circle C

N: The number of fiber intersections within the reference circle C (also includes Nb in the count)

Regarding the above content, 3 observation images are prepared for the same non-woven fabric sample for measurement, and the average result is used as the measurement value data.

Furthermore, FIG. 2 shows that there are a plurality of fiber intersections 6 where fibers 7 intersect with each other within the reference circle C attached to the observation screen, and a fiber intersection 6A that has been dyed.

In the nonwoven fabric of the present invention, the adhesive coating area ratio (K) on one side (first side) of the nonwoven fabric is preferably less than 0.05%, more preferably less than 0.03%, and further preferably less than 0.02% per unit area. In this way, the stickiness of the nonwoven fabric surface can be suppressed.

In addition, from the perspective of making the nonwoven fabric surface elastic, the adhesive coating area ratio (K) on one side (first side) of the nonwoven fabric is preferably 0.0001% or more.

From the perspective of better demonstrating the elastic effect of the adhesive, the adhesive coverage rate (K) on the opposite side (second side) of the nonwoven fabric is preferably 0.001% or more, more preferably 0.01% or more, and further preferably 0.025% or more per unit area.

In addition, from the perspective of preventing the adhesive from coming into contact with each other and causing the adhesive to increase in adhesion, the adhesive coating area ratio (K) on the opposite side (the second side) of the nonwoven fabric is preferably less than 1%.

The above-mentioned coverage area ratio (K) is obtained by measuring one side and the opposite side in the same manner as the above-mentioned (method for measuring the existence ratio of the adhesive at the intersection of fibers on either the front or back side of the nonwoven fabric when viewed from above). At this time, the coverage area ratio (K) of the adhesive is calculated by taking the area of the observation screen of the nonwoven fabric (the area obtained by adding the fibers (fibers covered by the adhesive and fibers not covered) and the spaces between the fibers) as the denominator.

In the nonwoven fabric of the present invention, in a cross section through the center of the thickness of the nonwoven fabric, the presence rate (H) of the above-mentioned adhesive at the intersection of the fibers in the center of the thickness is preferably 10% to 60% per unit area. The adhesive exists in the inner part in the thickness direction, so the thickness recovery of the nonwoven fabric is further improved, and a softer texture can be maintained.

In order to further enhance the above-mentioned effects, the presence rate (H) of the adhesive at the fiber intersection in the center of the thickness of the nonwoven fabric is preferably 20% or more, and more preferably 30% or more per unit area.

Furthermore, from the perspective of more effectively showing its elasticity than the adhesiveness of the adhesive, the presence rate (H) of the adhesive at the fiber intersection in the center of the thickness of the nonwoven fabric is preferably 50% or less, and more preferably 45% or less per unit area.

The definition of "thickness center" is the same as above.

The above-mentioned "cross section passing through the center of the thickness" refers to the cross section A passing through the center of the thickness and orthogonal to the fiber layer forming the nonwoven fabric surface as shown in the following (Method for determining the presence rate of the adhesive at the fiber intersection in the center of the thickness of the nonwoven fabric) and the cross section B passing through the center of the thickness and orthogonal to the cross section A.

(Method for determining the presence rate of adhesive at the intersection of fibers in the center of the thickness of nonwoven fabrics)

(4a) Carry out the processing of (1a) and (1b) of the above (measurement method of requirement (1)).

(4b) After freezing the nonwoven fabric sample with liquid nitrogen, cut it with a razor to make two sections passing through the center of the thickness of the nonwoven fabric sample. One of them is section A passing through the center of the thickness of the nonwoven fabric sample (a section passing through the center of the thickness and orthogonal to the fiber layer forming the nonwoven fabric surface). The other section is section B passing through the center of the thickness of the nonwoven fabric sample and orthogonal to the above section A.

Furthermore, the above-mentioned cross section can also be a cross section along the MD (Machine Direction) direction (the machine travel direction in the manufacturing step) of the non-woven fabric plane, a cross section along the CD (Cross Direction) direction (a direction orthogonal to the above-mentioned machine travel direction), or any cross section therebetween. As long as the cross section along at least any plane direction and passing through the center of the thickness meets the specified requirements, it is sufficient.

(4c) Place the sample prepared in (4b) above on a horizontal plane with the cross section facing upward. In the static state, use a digital microscope to take observation images at 100 times magnification.

(4d) For the observation images of the above two sections, the processing of (3b) of the above (the method for measuring the existence rate of the adhesive at the fiber intersection on either the front or back side of the nonwoven fabric when viewed from above) is performed to identify the measurement side. When the observation image of the thickness center of section A is obtained, the section sample is adjusted to the center of the observation screen from a low magnification, and then the magnification is gradually increased to identify the thickness center.

(4e) Then, based on the formula (S1) of (3c) above (the method for determining the existence rate of the adhesive at the fiber intersections on either the front or back side of the nonwoven fabric when viewed from above), the existence rate of the adhesive at the fiber intersections in the center of the thickness of the nonwoven fabric is calculated.

Regarding the above content, two observation images were prepared at three points in the same nonwoven fabric sample for measurement. The larger value of the measurement result of the existence rate of the adhesive at the fiber intersection in sections A and B was used, and the average value was used as the measurement value data.

The two sections A and B in (4b) above are, for example, the following sections.

When the fiber layer of the nonwoven fabric is continuous and flat in both the plane direction and the thickness direction, section A is a section that passes through the center of the thickness and is orthogonal to the fiber layer forming the nonwoven fabric surface (plane). In this case, section B is a section that passes through the center of the thickness and is along the plane of the nonwoven fabric. Specifically, section A is a section along the A-A line in the vertical direction passing through the center of the thickness 105 of the nonwoven fabric 100S as shown in Figure 3 (A). Section B is a section along the B-B line in the horizontal direction at the position of the center of the thickness 105 of the nonwoven fabric 100S as shown in Figure 3 (B).

Furthermore, when the fiber layer of the nonwoven fabric is curved in the thickness direction and has a concave-convex shape with alternating convex and concave portions, the section A is a section that passes through the center of the thickness and is orthogonal to the fiber layer that forms the nonwoven fabric surface (the surface of the wall connecting the top of the convex portion and the bottom of the concave portion). In this case, the section B is a section that passes through the center of the thickness and is along the fiber layer that forms the nonwoven fabric surface (the surface of the wall connecting the top of the convex portion and the bottom of the concave portion). Specifically, the section A is a section along the A-A line that passes through the center of the thickness 105 of the nonwoven fabric 100W as shown in FIG. 4 (A). Section B is a section along the B-B line (a line orthogonal to the A-A line) at the position of the thickness center 105 of the nonwoven fabric 100W as shown in FIG. 4(B).

In the nonwoven fabric of the present invention, when the nonwoven fabric is viewed from above, the presence rate (H) of the adhesive at the intersection of the fibers is preferably greater on the opposite side (the second side) than on one side (the first side) of the front and back sides of the nonwoven fabric.

When the nonwoven fabric of the present invention is used in contact with the skin, the opposite side (the second side) is preferably the side that does not contact the skin (the non-skin side). The above-mentioned side (the first side) is preferably the side that contacts the skin (the skin side). By having a large amount of adhesive on the non-skin side and a small amount of adhesive on the skin side, the thickness recovery under the action of the adhesive can be maintained, and the sticky feeling when in contact with the skin can be suppressed, maintaining the soft texture of the nonwoven fabric.

When the nonwoven fabric of the present invention is manufactured by the hot air method, due to the difference in heat during manufacturing, the fiber fusion points on the opposite side are relatively fewer than the side to which the hot air is blown, and the fabric presents a smooth texture. Therefore, in the nonwoven fabric of the present invention, it is preferred that the side to which the hot air is blown is the opposite side (the second side, the non-skin side) with more adhesive.

More specifically, when the nonwoven fabric is viewed from above, the presence rate (H) of the adhesive at the intersection of the fibers is preferably 10 percentage points greater on the opposite side than on one of the front and back sides of the nonwoven fabric.

Furthermore, regarding the presence rate (H) of the adhesive at the intersection of the fibers when the nonwoven fabric is viewed from above, it is preferably greater than 15 percentage points on the opposite side, and further preferably greater than 18 percentage points on one side of the front and back sides of the nonwoven fabric.

Furthermore, from the perspective of more effectively showing its elasticity than the adhesiveness of the adhesive, the presence rate (H) of the adhesive at the intersection of the fibers when the nonwoven fabric is viewed from above is greater on the opposite side than on one of the front and back sides of the nonwoven fabric, and the difference is preferably 50 percentage points or less, more preferably 30 percentage points or less, and further preferably 20 percentage points or less.

The presence rate of the adhesive at the fiber intersections when viewing the nonwoven fabric from the above one side and the opposite side in a plan view shall be determined in accordance with the above (the method for determining the presence rate of the adhesive at the fiber intersections on either the front or back side of the nonwoven fabric when viewed from a plan view).

Regarding (3b) of the above (method for determining the presence rate of adhesive at fiber intersections on either the front or back side of a nonwoven fabric when viewed from above), the number of fiber intersections (N) and the number of dyed fiber intersections (Nb) are counted for one side and the opposite side, respectively. Then, based on formula (S1) of (3c), the presence rate (H) (%) of each side is calculated. In addition, in the same nonwoven fabric sample, 3 observation images are prepared for each side and the opposite side for measurement, and the average value is used as the measurement value data.

Based on the measured data, the difference is calculated by subtracting the presence rate of the adhesive on the one side from the presence rate of the adhesive on the opposite side at the fiber intersection.

Furthermore, from the viewpoint of improving the effect of suppressing the stickiness of the surface in contact with the skin (skin surface), the coating area ratio (K1) of the adhesive on the one side is preferably 0.9 times or less, more preferably 0.6 times or less, and further preferably 0.53 times or less of the coating area ratio (K2) of the adhesive on the opposite side.

Furthermore, from the perspective of demonstrating resilience through the elasticity of the adhesive, the coating area ratio of the adhesive on one side is preferably 0.01 times or more, and more preferably 0.05 times or more, of the coating area ratio of the adhesive on the opposite side.

This can achieve both a soft texture and smooth skin surface.

Based on the viewpoint of suppressing the adhesiveness of the adhesive to the fibers so that the three-dimensional cross configuration of the fibers at the intersection of the fibers can be easily and smoothly restored, when the distance between the fibers is greater than the fiber diameter, the area of the adhesive between the fibers (gap) is preferably less than 15% per unit area, more preferably less than 5%, and further preferably less than 1%.

Furthermore, when the distance between fibers is greater than the fiber diameter, the area of adhesive between fibers (gap) is preferably as small as possible, but from the perspective of exhibiting the elasticity of the adhesive, it is actually more than 0.005%.

In the nonwoven fabric of the present invention, the ratio of the mass of the adhesive to the mass of the nonwoven fabric is preferably 1% or more and 20% or less. By keeping the mass of the adhesive contained in the nonwoven fabric of the present invention within the above range, the amount of adhesive fixation can be appropriately suppressed and the compression recovery of the nonwoven fabric can be effectively demonstrated.

In order to further improve the above-mentioned effect, the ratio of the mass of the adhesive to the mass of the above-mentioned non-woven fabric is preferably 7% or more, and further preferably 8% or more.

In addition, from the perspective of further improving the effect of suppressing stickiness, the ratio of the mass of the adhesive to the mass of the nonwoven fabric is preferably less than 10%, and further preferably less than 9%.

The ratio of the mass of the above-mentioned adhesive to the mass of the nonwoven fabric can be measured based on the above-mentioned (measurement method of requirement (2)).

In the nonwoven fabric of the present invention, it is preferred to include composite fibers containing two or more resin components having different melting points. By having such composite fibers, the nonwoven fabric can have strength and the adhesive can be applied more effectively. The strength of the nonwoven fabric is ensured by using composite fibers as heat-fusible fibers. Thereby, the amount of adhesive can be appropriately suppressed and the compression recovery of the nonwoven fabric can be more effectively demonstrated.

(Method for identifying resin components with different melting points)

By the following method, the melting point peak during differential scanning calorimetry is used to determine whether the composite fiber contains two or more resin components.

(5a) As a test sample, prepare 0.01 g of a nonwoven fabric sample that has been subjected to the same treatment as in (1a) of the above (Test method for requirement (1)).

(5b) Using a differential scanning calorimeter "DSC7000X" (trade name, manufactured by Hitachi High-Tech Sciences Corporation), 0.01 g of nonwoven fabric sample was weighed in an aluminum pan, the temperature was raised to 200°C, and then cooled from this temperature to 0°C at a rate of 10°C/min.

(5c) The temperature is raised to 300°C at a heating rate of 10°C/min, and the endothermic peak is measured. Here, when two or more peaks are measured, it is judged that the composite fiber contains two or more resin components.

In the nonwoven fabric of the present invention, the longitudinal orientation of the nonwoven fabric is preferably above 60%. As a result, the thickness recovery of the nonwoven fabric of the present invention is better and it is easier to maintain a soft texture.

In order to further improve the above-mentioned effects, the longitudinal orientation of the nonwoven fabric of the present invention is preferably above 65%, and further preferably above 70%.

In addition, from the perspective of improving the strength of the nonwoven fabric, the longitudinal orientation of the nonwoven fabric of the present invention is preferably less than 95%, more preferably less than 80%, and further preferably less than 75%.

The "longitudinal orientation" mentioned here is the value measured by the following (Method for measuring the longitudinal orientation of nonwoven fabrics), which indicates the degree of consistency of the fiber direction with thickness direction components.

(Method for determining the longitudinal orientation of nonwoven fabrics)

(6a) Freeze the nonwoven fabric sample with liquid nitrogen and place it on a horizontal plane. Then, use a razor to cut the portion of the nonwoven fabric sample at a position where the thickness is 50% in a direction perpendicular to the horizontal plane (the center of the thickness) to produce a thickness section (the section in the direction perpendicular to the horizontal plane).

(6b) The above thickness section was observed using a desktop scanning electron microscope "JCM- 6000Plus" (trade name, manufactured by JEOL Ltd.) at 35 times magnification, and the observation image was taken.

(6c) With respect to the above observation image, a reference line L is marked to form a square of 0.5 mm × 0.5 mm (the size within the observation image). Here, the reference line L is composed of an upper side L1 and a lower side L2 that are consistent in the direction along the above horizontal plane, and a left side L3 and a right side L4 that are consistent in the above vertical direction.

(6d) Count the number of fibers extending through the reference lines formed by the sides of the square. The number of fibers extending through the reference line L of the upper and lower sides L1 and L2 of the square is referred to as the "number of upper and lower fibers", and the number of fibers extending through the reference line L of the left and right sides L3 and L4 of the square is referred to as the "number of left and right fibers".

(6e) The longitudinal orientation Q of nonwoven fabric is calculated as (number of upper and lower fibers)/(number of upper and lower fibers + number of left and right fibers) × 100.

Regarding the above content, prepare 3 observation points on the same non-woven fabric sample for measurement, and use the average value as the measurement value data.

Furthermore, FIG. 5 shows an observation screen of a reference line L marked with a square. In the figure, the black dot 71 is the position where the fiber 7 passes through the reference line L (L1~L4).

When the above-mentioned "longitudinal orientation of nonwoven fabric" is higher, when the above-mentioned "existence rate of adhesive at fiber intersections" is higher, the resilience of nonwoven fabric is improved accordingly. In particular, when the longitudinal orientation is above the above lower limit % and the presence rate of adhesive at fiber intersections is above the above lower limit per unit area of nonwoven fabric, the longitudinal fiber intersections are elastically strengthened by the adhesive, which is better from the perspective of improving resilience.

The nonwoven fabric of the present invention preferably has the above-mentioned structure and has a concavo-convex shape in the thickness direction of the nonwoven fabric, and the concavo-convex shape has a convex part, a concave part, and a wall part connecting the convex part and the concave part. Because of the concavo-convex shape, the basis weight of the nonwoven fabric of the present invention can be suppressed, and it is more fluffy (with thickness) and has a good skin touch. Thereby, the compressibility of the nonwoven fabric of the present invention in the thickness direction is improved, and at the same time, it has compression recovery brought by the adhesive. That is, the nonwoven fabric of the present invention can significantly show thickness recovery relative to higher compressibility, and can have higher cushioning properties. In addition, the nonwoven fabric of the present invention can also maintain a high cushioning property after compression. Furthermore, in the nonwoven fabric of the present invention, unlike the previous resin-bonded nonwoven fabric, the amount of adhesive fixation can be suppressed within the range required for thickness recovery, thereby reducing the sticky feeling. Therefore, the fiber can be suppressed from sticking to the support body during the concave-convex shaping, thereby achieving good concave-convex shaping.

When the nonwoven fabric of the present invention has a concave-convex shape, it is preferred that the adhesive exists in the above-mentioned wall portion. This makes the above-mentioned effect more excellent.

The above-mentioned "concavoconvex shape" refers to a shape that varies according to the position in the direction perpendicular to the horizontal plane of the nonwoven fabric according to the cross-sectional shape of the nonwoven fabric. The above-mentioned "wall portion" refers to the fiber layer portion of the 50% area (hereinafter referred to as the thickness middle layer) located in the direction perpendicular to the horizontal plane when the nonwoven fabric of the present invention is placed statically on a horizontal plane, except for 25% on one side (the first side) and 25% on the opposite side (the second side) in the thickness (visual thickness) perpendicular to the horizontal plane.

Furthermore, the apparent thickness here refers to the value obtained using the measurement method of "thickness of nonwoven fabric" shown in the definition of "thickness center" above.

(Method to confirm the presence of adhesive on the wall)

(7a) For 0.3 g of a nonwoven fabric sample having an uneven shape, perform the dyeing treatments of (1a) and (1b) of the above (measurement method of requirement (1)).

(7b) When the nonwoven fabric sample is placed on a horizontal plane, a digital microscope is used to observe the wall portion at the middle layer of the thickness (visual thickness) in a direction perpendicular to the horizontal plane from a horizontal direction, and the observation image is photographed at 160 times.

(7c) The observed image is processed in the same manner as in (1d) above (the measurement method of requirement (1)) to calculate the adhesive presence area and fiber area.

Regarding the above content, the above measurements were performed at 3 points on the same sample, and the average value was used as the measurement value data.

As nonwoven fabrics with concavoconvex shapes, various nonwoven fabrics that are generally used as materials that come into contact with the skin can be used. For example, there are many types of concavoconvex shapes of nonwoven fabrics, such as solid convex parts, hollow convex parts, single-layer fiber layers, double-layer fiber layers, convex parts arranged in a scattered point shape in the plane direction, convex parts and concave parts arranged in a trench shape, etc. The various types of nonwoven fabrics can be specifically listed as shown in Figures 6 to 19.

The nonwoven fabrics with a double-layer structure in which the convex part of the concave-convex shape is solid are listed. For example, there is the following nonwoven fabric 10 (Specific Example 1).

The nonwoven fabric 10 (specific example 1) includes thermoplastic fibers and heat shrinkable fibers, and has a double-layer structure of an upper layer 11 on the first surface 1A (skin-contacting surface when used as a surface sheet) and a lower layer 12 on the second surface 1B (non-skin-contacting surface when used as a surface sheet). In addition, the two layers are joined by embossing (rolling) in the thickness direction from the first surface 1A (the portion to be embossed is referred to as an embossed concave portion (concave joining portion) 13). The lower layer 12 is a layer that exhibits heat shrinkage of the heat shrinkable fibers. By heat shrinking the lower layer 12, a solid protrusion 14 protruding toward the first surface 1A is provided in the upper layer 11 in the region of the embossed concave portion 13. In addition, a wall portion 15 connecting the protrusion 14 and the embossed concave portion 13 is provided in the upper layer 11.

The nonwoven fabric 10 typically has a shape as shown in FIG. 6 .

The nonwoven fabric 10 can be manufactured, for example, using the materials and manufacturing methods described in paragraphs [0032] to [0048] of Japanese Patent Publication No. 2002-187228.

The nonwoven fabrics with a hollow and double-layer structure in which the convex part of the concave-convex shape is enumerated. For example, there are the following nonwoven fabrics 20 (Specific Example 2) and nonwoven fabrics 30 (Specific Example 3).

The nonwoven fabric 20 (Specific Example 2) has a double-layer structure with a hollow portion 21. Each layer contains thermoplastic fibers. The nonwoven fabric 20 has a joint 22 formed by partially heat-melting the first nonwoven fabric 20A and the second nonwoven fabric 20B. In the non-joined portion surrounded by the joint 22, the first nonwoven fabric 20A has a plurality of convex portions 23, which protrude away from the second nonwoven fabric 20B and have a hollow portion 21 inside. A concave portion 24 located between the convex portions 23 and 23 is arranged in the arrangement area of the joint 22, thereby forming the concave and convex of the first surface 1A together with the convex portion 23. In addition, the nonwoven fabric 20 is provided with a wall portion 25 connecting the convex portion 23 and the concave portion 24.

The nonwoven fabric 20 typically has a shape as shown in FIG. 7 .

The nonwoven fabric 20 can be formed by a commonly used method. For example, after the first nonwoven fabric 20A is shaped into concave and convex shapes by engaging two concave and convex rollers, the second nonwoven fabric is bonded to obtain the nonwoven fabric 20.

The nonwoven fabric 30 (Specific Example 3) contains thermoplastic fibers and has a double-layer structure consisting of an upper layer 31 and a lower layer 32. Hollow convex portions 33 and concave portions 34 are alternately arranged in the upper layer 31, and the concave portions 34 form openings. The nonwoven fabric 30 is provided with a wall portion 35 connecting the convex portions 33 and the concave portions 34.

The nonwoven fabric 30 typically has a shape as shown in FIG. 8 .

This nonwoven fabric 30 can be manufactured, for example, by the method described in the 12th line of the lower left column on page 6 to the 19th line of the upper right column on page 8 of the Japanese Patent Publication No. 4-24263.

List the nonwoven fabrics with a single-layer structure having concave and convex shapes on both sides. For example, there are the following nonwoven fabric 40 (Specific Example 4) and nonwoven fabric 50 (Specific Example 5).

The nonwoven fabric 40 (Specific Example 4) has a single-layer structure including thermoplastic fibers, and has a concave-convex shape on both sides. Specifically, the first protrusion 41 protruding to the first surface 1A side and the second protrusion 42 protruding to the second surface 1B side are alternately and continuously arranged in different directions that intersect when the nonwoven fabric 40 is viewed from above. The first protrusion 41 and the second protrusion 42 have internal spaces released to the opposite sides of each other, and the portions form concave portions 43 and 44 of the corresponding surfaces. Thereby, the first surface 1A has a concave-convex shape of the first protrusion 41 and the concave portion 44. In addition, the second surface 1B has a concave-convex shape of the second protrusion 42 and the concave portion 43. In addition, the nonwoven fabric 40 has a wall portion 45 connecting the first protrusion 41 and the second protrusion 42. The wall portion 45 forms the wall surface of the inner space of each of the first protrusion 41 and the second protrusion 42, and has an annular structure in the plane direction. The fibers constituting the wall portion 45 connect the first protrusion 41 and the second protrusion 42 at any point of the annular structure, and have fiber orientation in the thickness direction of the non-woven fabric.

The nonwoven fabric 40 typically has a shape as shown in FIG. 9 .

The nonwoven fabric 30 can be manufactured using the hot air processing manufacturing method described in paragraphs [0031] and [0032] of Japanese Patent Publication No. 2012-136790.

The nonwoven fabric 50 (Specific Example 5) has a single-layer structure including thermoplastic fibers, and has a concave-convex shape formed by alternating stripe-shaped convex portions 51 and concave portions 52 on the first surface 1A side. On the second surface 1B side, concave portions 53 corresponding to the convex portions 51 on the first surface 1A side and convex portions 54 corresponding to the concave portions 52 on the first surface 1A side are alternately arranged to form a concave-convex shape. The nonwoven fabric 50 is provided with a wall portion 55 connecting the convex portion 51 and the concave portion 52 (the concave portion 53 and the convex portion 54).

The nonwoven fabric 50 typically has a shape as shown in FIG. 10 .

The nonwoven fabrics whose convex parts of the concave-convex shape are solid and have a single-layer structure are listed. For example, there are the following nonwoven fabrics 60 (Specific Example 6) and nonwoven fabrics 70 (Specific Example 7).

The nonwoven fabric 60 (Specific Example 6) has a single-layer structure including thermoplastic fibers, and has a shape in which a plurality of semi-cylindrical solid protrusions 61 and concave portions 62 arranged along the side edges of the protrusions 61 are arranged alternately on the first surface 1A. On the lower side of the concave portion 62, a concave portion bottom 63 composed of nonwoven fabric fibers is arranged. In addition, a wall 64 connecting the protrusion 61 and the concave portion 62 is arranged in the nonwoven fabric 60.

The nonwoven fabric 60 typically has the shape shown in FIG. 11 .

The nonwoven fabric 70 (Specific Example 7) has a single-layer structure including thermoplastic fibers and heat-extensible fibers, and has a concave-convex shape on the first surface 1A side. The second surface 1B side is flat, or the degree of concave-convexity is extremely small compared to the first surface 1A side. The concave-convex shape on the first surface 1A side specifically has a plurality of solid protrusions 71 and linear concave portions 72 surrounding the solid protrusions 71. The linear concave portions 72 are arranged in a lattice shape, and the protrusions 71 are dispersed in each area divided by the lattice. The concave portion 72 has a press-welded joint portion formed by pressing or welding the constituent fibers of the nonwoven fabric 70, and the heat-extensible fibers are in a non-stretched state. The convex portion 71 is a portion that is convex toward the first surface 1A side due to the heat-extensible fiber being heat-extensible. In addition, the non-woven fabric 70 has a wall portion 73 that connects the convex portion 71 and the concave portion 72.

The nonwoven fabric 70 typically has the shape shown in FIG. 12 .

This nonwoven fabric 70 can be manufactured by performing a linear heat embossing process on a fiber web and then using a hot air process to stretch the heat-stretchable fibers.

The nonwoven fabric is a single-layer structure in which the convex part of the concavo-convex shape is hollow and both sides of the nonwoven fabric have concavo-convex shapes. For example, there are the following nonwoven fabric 80 (Specific Example 8) and nonwoven fabric 90 (Specific Example 9).

The nonwoven fabric 80 (Specific Example 8) has a single-layer structure including thermoplastic fibers and has the concave-convex shape shown below.

That is, it has outer surface fiber layers 81 and 82 on the first surface 1A side and the second surface 1B side, and a plurality of connecting parts 83 arranged between the outer surface fiber layer 81 on the first surface 1A side and the outer surface fiber layer 82 on the second surface 1B side. Part of the fibers between the outer surface fiber layer 81 on the first surface 1A side and the outer surface fiber layer 82 on the second surface 1B side and the connecting parts 83 are fused.

The nonwoven fabric 80 has a concavo-convex shape in the thickness direction thereof by means of the outer surface fiber layers 81, 82 and the connecting portion 83, and the concavo-convex shape has hollow convex portions, concave portions and a wall portion connecting the convex portions and the concave portions. The concavo-convex shape is formed on both the first surface 1A side and the second surface 1B side. Specifically, on the first surface 1A side, the convex portion formed by the outer surface fiber layer 81 and the concave portion 88 between the outer surface fiber layer 81 have a concavo-convex shape. On the second surface 1B side, the convex portion formed by the outer surface fiber layer 82 and the concave portion 89 between the outer surface fiber layer 82 have a concavo-convex shape. The convex portion formed by the outer surface fiber layer 81 and the convex portion formed by the outer surface fiber layer 82 are both hollow. The connecting portion 83 forms a wall portion 83 that connects the convex portion and the concave portion 88 (convex portion and concave portion 89).

Regarding the nonwoven fabric 80, various structures described in paragraphs [0010] to [0048] of Japanese Patent Publication No. 2019-44319 can be adopted. For example, the concave-convex shape of the nonwoven fabric 80 can also be a shape in which the convex portion formed by the outer surface fiber layer 81 on the first surface 1A side and the concave portion 88 therebetween are arranged in a trench shape. Similarly, the convex portion formed by the outer surface fiber layer 82 on the second surface 1B side and the concave portion 89 therebetween can also be arranged in a trench shape. In addition, the outer surface fiber layers 81 and 82 can also be oriented in the plane direction. The wall portion 83 formed by the connecting portion 83 includes fibers having a thickness direction component. The outer surface fiber layer 81 that becomes the convex portion on the first surface 1A side has two types (the first outer surface fiber layer 81A and the second outer surface fiber layer 81B), and the two types have lengths extending in different directions along the non-woven fabric in a top view. The plurality of connecting parts 83 may also have two types (the first connecting part 83A and the second connecting part 83B) arranged in different directions along the non-woven fabric in a top view so that the directions of the wall surfaces of the connecting parts 83 are different from each other. In this case, the first connecting part 83A and the second connecting part 83B can align the fibers longitudinally even if the directions of the wall surfaces are different from each other.

The nonwoven fabric 80 typically has a shape as shown in FIG. 13 .

This nonwoven fabric 80 can be manufactured by the method described in paragraphs [0049] to [0057] of Japanese Patent Publication No. 2019-44319.

The nonwoven fabric 90 (Specific Example 9) has a single-layer structure including thermoplastic fibers and has the concave-convex shape shown below.

That is, on the first surface (one side) 1A side, a plurality of longitudinal ridges 911 protruding toward the first surface 1A side in the thickness direction of the nonwoven fabric are arranged to extend along one direction of the first surface 1A side in a top view. The longitudinal ridges 911 are arranged at intervals in another direction of the first surface 1A side in a top view different from the one direction of the first surface 1A side. In addition, the transverse ridges 921 extending in another direction of the first surface 1A side are arranged in a manner of connecting the longitudinal ridges 911. The longitudinal ridges 911 and the transverse ridges 921 are respectively formed as hollow convex portions. The nonwoven fabric 90 has a concave-convex shape in the thickness direction thereof by means of the longitudinal ribs 911 and the transverse ribs 921 and the concave portion 922 therebetween, and the concave-convex shape has a convex portion, a concave portion, and a wall portion 911W connecting the convex portion and the concave portion. On the first surface 1A side, the convex portion formed by the longitudinal ribs 911 and the transverse ribs 921 has a length extending in each direction along different directions intersecting the nonwoven fabric 90 in a top view. In this case, the concave-convex shape on the first surface side of the nonwoven fabric 90 may also be a shape in which the convex portions formed by the longitudinal ribs 911 and the transverse ribs 921 and the concave portion therebetween are arranged in a rib groove shape.

Furthermore, on the second surface (opposite surface) 1B side, a plurality of hollow convex stripes 931 are arranged, and the convex stripes 931 extend in one direction of the second surface 1B side when viewed from above, and are arranged in another direction of the second surface 1B side that is different from the one direction of the second surface 1B side. Furthermore, the concave stripes 936 sandwiched between the plurality of convex stripes 931 extend in one direction of the second surface 1B side. The concave-convex shape of the second surface 1B side of the non-woven fabric 90 has a shape in which the convex stripes 931 and the concave stripes 936 are arranged in a groove shape. The convex stripes 931 are formed by connecting a plurality of convex parts 934 in a ridge shape, and the thinner width parts and the thicker width parts are alternately connected and arranged when viewed from above. There is a slightly lower concave portion 935 between the ridge-shaped convex portions 934. The non-woven fabric 90 has a concave-convex shape in its thickness direction by means of the convex stripe portion 931 and the concave stripe portion 936. The concave-convex shape has a convex portion, a concave portion, and a wall portion 931W connecting the convex portion and the concave portion.

Regarding the nonwoven fabric 90, various structures described in paragraphs [0012] to [0058] of Japanese Patent Publication No. 2019-44320 may be adopted. For example, the orientation direction of the fibers constituting the longitudinal ridge 911 and the fibers constituting the transverse ridge 921 may be different. The height of the longitudinal ridge 911 may be different from the height of the transverse ridge 921, and the transverse ridge 921 may be bent in the thickness direction of the nonwoven fabric 90, or may be set to a uniform height. In addition, when viewed from the side of the second surface 1B, the two lines constituting the width direction of the ridge 931 may be curved lines having multiple arcs. Fine hairs may also be arranged on the side of the ridge 931.

The nonwoven fabric 90 typically has the shape shown in FIGS. 14 to 19 .

This nonwoven fabric 90 can be manufactured by the method described in paragraphs [0059] to [0065] of Japanese Patent Publication No. 2019-44320.

The thermoplastic fiber and adhesive constituting the nonwoven fabric of the present invention are described.

As thermoplastic fibers, fibers commonly used as non-woven fabric materials can be used without particular restrictions. For example, it can be a fiber composed of a single resin component, or a composite fiber composed of multiple resin components. Composite fibers include core-sheath type and parallel type.

When a composite fiber containing a low melting point component and a high melting point component (e.g., a core-sheath type composite fiber in which the sheath is a low melting point component and the core is a high melting point component) is used as the thermoplastic fiber, the temperature of the hot air blown to the fiber web in the manufacturing step is preferably higher than the melting point of the low melting point component and lower than the melting point of the high melting point component. It is more preferably a temperature higher than the melting point of the low melting point component and 10°C lower than the melting point of the high melting point component, and further preferably a temperature higher than the melting point of the low melting point component by more than 5°C and lower than the melting point of the high melting point component by more than 20°C. In addition, from the perspective of elasticity, the more cores of the core-sheath type composite fibers are as high melting point components, the higher the elasticity. Therefore, in terms of cross-sectional area ratio, the larger the core component, the better. As a specific example of a core-sheath type composite fiber in which the sheath is a low melting point component and the core is a high melting point component, there can be cited a core-sheath type composite fiber in which the sheath is PE and the core is PET.

In addition, in core-sheath type composite fibers, when the glass transition temperature of the sheath resin component is lower than that of the core resin component (hereinafter referred to as low glass transition temperature resin) (for example, the core resin component is PET and the sheath resin component is PE), the thickness recovery of the nonwoven fabric can be further improved by reducing the mass ratio of the low glass transition temperature resin component.

As the adhesive, various adhesives can be used. For example, acrylic resins, ester resins, vinyl acetate resins, styrene resins, vinyl acetate-ethylene resins, styrene butadiene rubber, etc. can be listed.

As the material having the viscosity, adhesiveness and softness to restore the three-dimensional cross configuration of the fibers at the fiber intersections, acrylic resin, styrene butadiene rubber, etc. are particularly preferred.

"Acrylic resin" refers to a polymer that contains at least one of a (meth)acrylic acid compound component and a (meth)acrylic acid derivative compound component as a main component. The bonding form of the components in the above acrylic resin is not particularly limited, and the acrylic resin can be a block polymer or a random polymer.

"(Meth)acrylic acid compound" refers to (meth)acrylic acid and its salts. Examples of counter ions constituting the salt of (meth)acrylic acid include alkali metal ions such as sodium ions and potassium ions, and alkaline earth metal ions such as magnesium ions and calcium ions.

"(Meth)acrylic acid derivative compounds" refer to compounds (monomers) that can be derived from (meth)acrylic acid compounds. Examples of (meth)acrylic acid derivative compounds include (meth)acrylates, (meth)acrylamide, and (meth)acrylonitrile.

The (meth)acrylic acid compound and the (meth)acrylic acid derivative compound may be used alone or in combination of two or more.

As the (meth)acrylic acid derivative compound used in the nonwoven fabric of the present invention, (meth)acrylate or (meth)acrylamide is preferred, and (meth)acrylate is more preferred.

In (meth)acrylamide, the two hydrogen atoms of the nitrogen atom constituting the amide bond may be substituted by any substituent such as an alkyl group. The alkyl group may be an unsubstituted alkyl group or an alkyl group having a substituent. Examples of the alkyl group having a substituent include an alkyl group having an amino group as a substituent which may be substituted by any substituent such as an alkyl group, and an alkyl group having an acyl group as a substituent.

Among them, unsubstituted (meth)acrylamide and alkyl (meth)acrylamide are preferably listed.

As (meth)acrylates, for example, alkyl (meth)acrylates, polyalkylene glycol (meth)acrylates, aryl (meth)acrylates, and heteroaryl (meth)acrylates can be cited, preferably alkyl (meth)acrylates or polyalkylene glycol (meth)acrylates.

The alkyl group bonded to the oxygen atom of the ester bond constituting the (meth)acrylic acid alkyl ester may be an unsubstituted alkyl group or an alkyl group having a substituent. Examples of the alkyl group having a substituent include a hydroxyalkyl group, an alkyl group having an amino group as a substituent which may be substituted by any substituent such as an alkyl group, and an alkyl group having a betaine structure. As the betaine structure, a carboxybetaine structure such as a carboxyquaternary ammonium structure is preferred, and a carboxydialkylammonium structure is more preferred.

The acrylic resin used for the nonwoven fabric of the present invention preferably has (meth)acrylic acid and its salts, and at least one component derived from (meth)acrylic acid esters, and more preferably has acrylic acid and its salts, and at least one component derived from acrylic acid esters.

The acrylic resin used for the nonwoven fabric of the present invention may also have constituent components derived from compounds (monomers) other than (meth)acrylic acid compounds and (meth)acrylic acid derivatives. Examples of such compounds include ethylene, propylene, isopropylene, vinyl acetate, vinyl chloride, styrene, vinyl pyrrolidone, and urethane compounds (monomers having urethane bonds).

Specific examples of acrylic resins for use in the nonwoven fabric of the present invention include (acrylic acid/tert-butyl acrylamide) copolymers, (acrylic acid/acrylamide) copolymers such as (acrylic acid/acrylamide/ethyl acrylate) copolymers, (acrylic acid/acrylamide/alkyl acrylate) copolymers, (alkyl acrylamide/acrylic acid/alkylaminoalkyl acrylamide/polyethylene glycol methacrylate) copolymers, alkyl acrylate polymers, alkyl methacrylate copolymers, (acrylic acid/alkyl acrylate) copolymers, (acrylic acid/methacrylic acid) copolymers, and the like. (alkyl acrylate) copolymers, (methacrylic acid/alkyl acrylate) copolymers, (methacrylic acid/alkyl methacrylate) copolymers, (alkyl acrylate/tert-butylacrylamide) copolymers or (alkyl acrylate/octylacrylamide) copolymers, (alkyl acrylate/acrylamide) copolymers, (acrylic acid/alkyl acrylate/tert-butylacrylamide) copolymers, (acrylic acid/alkyl acrylate/alkylacrylamide) copolymers, (methacrylic acid/alkyl acrylate/alkylacrylamide) copolymers, (methacrylic acid/alkyl acrylate/alkylacrylamide) copolymers, (methacryloxy Ethyl carboxybetaine/alkyl methacrylate) copolymer, (alkyl acrylamide/alkylaminoalkyl acrylamide/polyethylene glycol methacrylate) copolymer, (octylacrylamide/hydroxypropyl acrylate/butylaminoethyl methacrylate) copolymer, (alkyl acrylamide/alkyl acrylate/alkylaminoalkyl acrylamide/polyethylene glycol methacrylate) copolymer, (alkyl acrylate/diacetone acrylamide) copolymer, (styrene/acrylic acid) copolymer, (styrene/alkyl acrylate) copolymer, (styrene/acrylamide) copolymer ) copolymer, urethane-acrylic copolymer (copolymer of urethane compound and acrylic compound or its derivative), (vinyl pyrrolidone/acrylic acid/methacrylic acid) copolymer, (vinyl pyrrolidone/alkyl acrylate/methacrylic acid) copolymer, (octylacrylamide/hydroxypropyl acrylate/butylaminoethyl methacrylate) copolymer, (methacryloyloxyethyl carboxybetaine/alkyl methacrylate) copolymer, (acrylic acid/alkyl acrylate/ethyl methacrylate amine oxide) copolymer, etc.

<Adhesive coating material for non-woven fabrics>

In the nonwoven fabric of the present invention, the above-mentioned adhesive can be used as an adhesive coating material for nonwoven fabric containing the adhesive. The adhesive coating material for nonwoven fabric can be composed only of the above-mentioned adhesive, and can also contain other components within the range that does not damage the above-mentioned properties.

For example, as a component of the adhesive coating material for nonwoven fabrics, in addition to the adhesive, there can be listed solvents, dispersants for making the adhesive dissolve in the solvent, emulsifiers or solubilizers, etc.

As the above-mentioned solvent, water, ethanol, isopropyl alcohol, alcohols such as propylene glycol, glycol ethers such as propylene glycol monomethyl ether and diethylene glycol butyl ether can be cited. From the perspective of improving the working environment and preventing fiber deterioration, water is preferred.

The content of the adhesive of the present invention in the adhesive coating material for nonwoven fabric can be appropriately set within the range that does not damage the above characteristics. Based on the viewpoint of showing the resilience by the elasticity of the adhesive, the content of the adhesive of the present invention is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and the upper limit is 100% by mass.

Furthermore, in the nonwoven fabric of the present invention, it is preferred that the basis weight within the nonwoven fabric is different, and there is a region with a smaller basis weight in the middle layer of the thickness. Thus, the adhesive is attached to the center of the thickness, and the recoverability can be exhibited.

Based on the same viewpoint, it is preferred that the nonwoven fabric of the present invention has a core-sheath type thermoplastic composite fiber, in which the core-sheath ratio (mass ratio) of the fiber is different, and there is a region with a smaller sheath ratio (mass ratio) in the middle layer of the thickness.

The nonwoven fabric of the present invention can be used for various purposes, for example, in absorbent articles. Absorbent articles typically have a front sheet disposed on the skin-contacting side, a back sheet disposed on the non-skin-contacting side, and an absorbent body sandwiched between the front sheet and the back sheet. In such absorbent articles, the nonwoven fabric of the present invention can be appropriately used as the front sheet of absorbent articles such as diapers, sanitary napkins, sanitary pads, and urine absorbent pads. Furthermore, the forms of pleated sheets, outer sheets, and wing sheets used as absorbent articles can also be listed.

In addition, the non-woven fabric of the present invention can be used as a component of an eye mask or a mask.

Regarding the above-mentioned implementation method, the present invention further discloses the following nonwoven fabric and absorbent article.

<1>

A nonwoven fabric having an adhesive and thermoplastic fibers, and having fusion points between the fibers, wherein at the center of the thickness of the nonwoven fabric, there is a fiber intersection where fibers having thickness direction components intersect with other fibers, and the adhesive exists at the fiber intersection, and the adhesive satisfies one or both of the following requirements (1) and (2).

(1) When the nonwoven fabric is viewed from above, the area ratio of the adhesive per unit area is smaller than the area ratio of the fibers not covered by the adhesive.

(2) The ratio of the mass of the above-mentioned adhesive to the mass of the above-mentioned nonwoven fabric is at least 65 percentage points less than the ratio of the mass of the fiber to the mass of the above-mentioned nonwoven fabric.

<2>

For the nonwoven fabric of <1>, the ratio of the mass of the adhesive to the mass of the nonwoven fabric is at least 78 percentage points smaller than the ratio of the mass of the fiber to the mass of the nonwoven fabric, preferably at least 81 percentage points smaller.

<3>

The nonwoven fabric of <1> or <2>, wherein the amount of adhesive in the nonwoven fabric is greater on the opposite side than on one of the front and back sides, and the requirement of (1) is satisfied on the one side.

<4>

A nonwoven fabric as described in any one of <1> to <3> above, wherein the adhesive is present at the fusion point between the fibers.

<5>

A nonwoven fabric as described in any one of <1> to <4> above, wherein when the nonwoven fabric is viewed from above, the presence rate of the adhesive at the intersection of fibers on at least one of the front and back sides of the nonwoven fabric is 5% to 60% per unit area of the nonwoven fabric.

<6>

For the nonwoven fabric of <5>, the presence rate of the above-mentioned adhesive at the fiber intersection is 10% or more, preferably 20% or more, per unit area of the nonwoven fabric.

<7>

For the nonwoven fabric of <5> or <6>, the presence rate of the above-mentioned adhesive at the fiber intersection is less than 50% per unit area of the nonwoven fabric, preferably less than 35%.

<8>

For a nonwoven fabric as described in any one of <5> to <7> above, any of the above-mentioned sides is the side that does not come into contact with the skin when the nonwoven fabric is used.

<9>

A nonwoven fabric as described in any one of <1> to <8> above, wherein in a cross section through the center of the thickness of the nonwoven fabric, the presence rate of the adhesive at the intersection of the fibers in the center of the thickness is not less than 10% and not more than 60% per unit area of the nonwoven fabric.

<10>

As in the nonwoven fabric of <9> above, in the cross section through the center of the thickness of the nonwoven fabric, the presence rate of the adhesive at the intersection of the fibers in the center of the thickness is 20% or more, preferably 30% or more, per unit area of the nonwoven fabric.

<11>

For the nonwoven fabric of <9> or <10>, in the cross section through the center of the thickness of the nonwoven fabric, the presence rate of the adhesive at the intersection of the fibers in the center of the thickness is less than 50% per unit area of the nonwoven fabric, preferably less than 45%.

<12>

A nonwoven fabric as described in any one of <1> to <11> above, wherein the presence rate of the adhesive at the intersection of fibers when the nonwoven fabric is viewed from above is greater on the opposite side than on one of the front and back sides of the nonwoven fabric.

<13>

A nonwoven fabric as described in any one of <1> to <12> above, wherein the presence rate of the adhesive at the intersection of the fibers when the nonwoven fabric is viewed from above is greater than that on one of the front and back sides of the nonwoven fabric by more than 10 percentage points, preferably greater than 15 percentage points, and more preferably greater than 18 percentage points.

<14>

A nonwoven fabric as described in any one of <5> to <13> above, wherein the fiber intersections in the presence rate of the above-mentioned adhesive at the fiber intersections are fusion points.

<15>

A nonwoven fabric as described in any one of <1> to <14> above, wherein the adhesive coverage area ratio on one side of the nonwoven fabric is less than 0.9 times the adhesive coverage area ratio on the opposite side, preferably less than 0.6 times, and more preferably less than 0.53 times.

<16>

For example, the nonwoven fabric of <15>, wherein the adhesive coating area ratio on one side of the nonwoven fabric is 0.01 times or more, preferably 0.05 times or more, of the adhesive coating area ratio on the opposite side.

<17>

For a nonwoven fabric as described in any one of <1> to <16> above, when the distance between fibers is greater than the fiber diameter, the area of adhesive between fibers (gaps) is less than 15% per unit area, preferably less than 5%, more preferably less than 1%, and more preferably more than 0.005%.

<18>

For any nonwoven fabric as described in <1> to <17>, the mass of the above-mentioned adhesive is not less than 1% and not more than 20% of the mass of the above-mentioned nonwoven fabric.

<19>

For the nonwoven fabric of <18>, the mass of the adhesive is at least 7% of the mass of the nonwoven fabric, preferably at least 8%.

<20>

For the nonwoven fabric of <18> or <19>, the mass of the adhesive is less than 10% of the mass of the nonwoven fabric, preferably less than 9%.

<21>

A nonwoven fabric as described in any one of <1> to <20> above, wherein the nonwoven fabric comprises composite fibers having two or more resin components with different melting points.

<22>

A nonwoven fabric as described in any one of <1> to <21> above, wherein the longitudinal orientation of the nonwoven fabric is 60% or more, preferably 65% or more, and more preferably 70% or more.

<23>

A nonwoven fabric as described in any one of <1> to <22> above, wherein the longitudinal orientation of the nonwoven fabric is less than 95%, preferably less than 80%, and more preferably less than 75%.

<24>

A nonwoven fabric as described in any one of <1> to <23> above, wherein the nonwoven fabric has a concave-convex shape in the thickness direction, and the concave-convex shape has a convex portion, a concave portion, and a wall portion connecting the convex portion and the concave portion.

<25>

As in the nonwoven fabric of <24>, the adhesive is present in the wall portion.

<26>

A nonwoven fabric as described in any one of <1> to <25> above, wherein the basis weights of the nonwoven fabric are different, and a region with a smaller basis weight is present in the middle layer of the thickness.

<27>

A nonwoven fabric as described in any one of <1> to <26> above, wherein the core-to-sheath ratio (mass ratio) of the fibers in the nonwoven fabric is different, and a region with a smaller sheath ratio (mass ratio) is present in the middle layer of the thickness.

<28>

The nonwoven fabric of any one of <1> to <27>, wherein the adhesive is preferably one or more selected from acrylic resins, ester resins, vinyl acetate resins, styrene resins, vinyl acetate-ethylene resins, styrene-butadiene rubbers, preferably acrylic resins or styrene-butadiene rubbers, more preferably acrylic resins, further preferably (meth)acrylates or (meth)acrylamides, further preferably (meth)acrylates.

<29>

For a nonwoven fabric as described in any one of <1> to <28> above, in relation to the requirement (1) above, the difference (M2-M1) between the area ratio (M1) of the adhesive present per unit area and the area ratio (M2) of the fiber not covered by the adhesive is 80 percentage points or more, preferably 90 percentage points or more, and more preferably 99 percentage points or more.

<30>

For a nonwoven fabric as described in any one of <1> to <29> above, in relation to the requirement (1) above, the difference (M2-M1) between the area ratio (M1) of the adhesive present per unit area and the area ratio (M2) of the fiber not covered by the adhesive is 99.99 percentage points or less, preferably 99.95 percentage points or less, and more preferably 99.9 percentage points or less.

<31>

A nonwoven fabric as described in any one of <24> to <30> above, wherein the above-mentioned concavo-convex shape has a structure selected from one structure or a combination of multiple structures, such as a solid convex part, a hollow convex part, a single-layer fiber layer, a double-layer fiber layer, a convex part arranged in a scattered point shape in the plane direction, and a convex part and a concave part arranged in a trench shape.

<32>

A nonwoven fabric as described in any one of <1> to <31> above, having a concave-convex shape on both sides.

<33>

A nonwoven fabric as described in any one of <1> to <32> above, which has one of the front and back sides of the nonwoven fabric and an opposite side which is the opposite side to the one side,

It has the outer surface fiber layer on the one side and the opposite side, and a plurality of connecting parts arranged between the outer surface fiber layer on the one side and the outer surface fiber layer on the opposite side,

The outer surface fiber layer on one side and the outer surface fiber layer on the opposite side and the connecting portion are partially fused to each other.

<34>

The nonwoven fabric as described in <33> above has a concave-convex shape in which the convex parts formed by the outer surface fiber layer on one side and the concave parts therebetween are arranged in a groove shape, and has a concave-convex shape in which the convex parts formed by the outer surface fiber layer on the opposite side and the concave parts therebetween are arranged in a groove shape.

<35>

A nonwoven fabric as described in any one of <1> to <32> above, which has one of the front and back sides of the nonwoven fabric and an opposite side opposite to the one side, On the one side, a plurality of longitudinal ribs protruding toward the one side in the thickness direction of the nonwoven fabric extend along one direction of the one side in a top view, and are arranged at intervals in another direction of the one side in a top view different from the one direction of the one side, and a transverse rib extending in the other direction of the one side is arranged in a manner to connect the longitudinal ribs.

<36>

The nonwoven fabric as mentioned above <35> has a concave-convex shape in which the convex parts formed by the longitudinal ridge and the transverse ridge on one side and the concave parts therebetween are arranged in a ridge groove shape.

<37>

A nonwoven fabric as described in any one of <1> to <36> above, which has a convex strip extending in one direction, wherein the convex strip has a plurality of convex portions connected in a ridge shape, and in a top view, a thinner portion and a thicker portion are alternately connected.

<38>

A nonwoven fabric as described in any one of <1> to <37> above, wherein the apparent thickness of the nonwoven fabric under a load of 50 Pa is 1.3 mm to 15 mm, preferably 1.5 mm to 1.5 mm, more preferably 2.0 mm to 3.0 mm, more preferably 4.5 mm to 5.5 mm, and preferably 10 mm to 10 mm, more preferably 9 mm to 10 mm, and more preferably 8.5 mm to 10 mm.

<39>

A nonwoven fabric as described in any one of <1> to <38> above, wherein the basis weight of the nonwoven fabric is from 10 g/ ^m2 to 60 g/ ^m2 , preferably from 15 g/ ^m2 to 20 g/ ^m2 , more preferably from 25 g/ ^m2 to 55 g/ ^m2 , more preferably from 50 g/ ^m2 to 48 g/ ^m2 .

<40>

An absorbent article having a nonwoven fabric as described in any one of <1> to <39> above.

<41>

An absorbent article having a front sheet disposed on the skin-contacting side, a back sheet disposed on the non-skin-contacting side, and an absorbent body sandwiched between the front sheet and the back sheet, and having a nonwoven fabric as any one of <1> to <39> as the front sheet.

<42>

For example, in the absorbent article of <41>, the side opposite to the one side of the front and back sides of the nonwoven fabric is the side that does not come into contact with the skin.

[Implementation example]

The present invention is described in more detail below based on the examples, but the present invention is not limited to the examples. Furthermore, "points" and "%" in the examples are all quality standards unless otherwise specified. "-" in the following table indicates that the value does not meet the item, etc.

(Implementation Example 1) (1) Production of raw non-woven fabrics

Using core-sheath thermoplastic composite fibers with fiber diameters shown in Table 1, raw nonwoven fabrics with concave and convex shapes as shown in Figures 14 to 19 were produced by hot air method. The size of the raw nonwoven fabric was set to 100mm×100mm.

Specifically, the manufacturing method described in paragraphs [0059] to [0065] of Patent Document 4 is used for the production. At this time, the first hot air blowing treatment is performed at a temperature of 160°C, a wind speed of 54m/sec, and a blowing time of 6 seconds. The second hot air blowing treatment is performed at a temperature of 160°C, a wind speed of 6m/sec, and a blowing time of 6 seconds.

(2) Preparation of adhesive coating liquid

The adhesive coating solution is prepared by mixing an adhesive solution with a solid content of about 50% at 10% by mass and deionized water at 90% by mass. The adhesive used is a highly elastic type of commercially available acrylic emulsion (BONKOTE AB-886 (trade name, manufactured by DIC Corporation), pH 6.6, viscosity 40mPa.s, glass transition point -40°C, ingredients: acrylic resin 50.8% by mass, n-butyl acrylate less than 1% by mass, isopropyl alcohol less than 1% by mass, other ingredients less than 1% by mass, and the remainder is water).

(3) Spraying of adhesive coating liquid

Then, the adhesive coating liquid is evenly applied by a sprayer to the second surface (opposite surface) 1B of the raw nonwoven fabric having the convex stripe portion 931 and the concave stripe portion 936. The amount of the adhesive coating liquid applied is set to 3.5 g/m ² . The amount of the adhesive coating liquid is measured by the change in the mass of the nonwoven fabric before and after the adhesive is applied.

Thus, a nonwoven fabric sample A1 of Example 1 having a basis weight shown in Table 1 was prepared. The adhesive exists in a manner of being attached to the thickness center of the nonwoven fabric and particularly attached to the fiber intersections.

(Example 2)

The nonwoven fabric sample A2 of Example 2 is prepared in the same manner as Example 1 except that the basis weight is set to that shown in Table 1. The adhesive exists in a manner of being attached to the thickness center of the nonwoven fabric and particularly attached to the fiber intersections.

(Implementation Example 3)

The nonwoven fabric sample A3 of Example 3 was prepared in the same manner as Example 1 except that the fiber diameter and basis weight were set as shown in Table 1.

(Implementation Example 4)

In the production method described in paragraphs [0059] to [0065] of patent document 4, the protrusion height of the support is changed to 6.0 mm and the apparent thickness and basis weight of the nonwoven fabric under a load of 50 Pa are set as shown in Table 1, so that the bulkiness is lower than that of Example 1. In addition, the nonwoven fabric sample A4 of Example 4 is produced in the same manner as Example 1.

(Example 5)

As a raw material nonwoven fabric, the nonwoven fabric sample A5 of Example 5 is prepared by the same method as Example 1 except that it is prepared by the manufacturing method described in paragraphs [0049] to [0057] of Patent Document 3 using the support shown in FIG. 20. The nonwoven fabric sample A5 has the concave-convex shape shown in FIG. 13.

Furthermore, in the above-mentioned manufacturing method, as the support body male material 120 shown in FIG. 20, a square of 2 mm×2 mm in size with a protrusion 121 having a height of 8 mm and a corner column shape is used. The distance between the corner columns is 5 mm in the MD direction and the CD direction. As the support body mother material 130 shown in FIG. 20, a metal material having a grid-like protrusion 131 corresponding to the concave portion 122 of the support body male material 120 is used. The protrusion 131 of the support body mother material 130 is pressed into the protrusion 121 of the support body male material 120. The adjacent protrusions 121, 121 of the support body matrix 130 are arranged at a distance of 5mm. When the support body male material 120 and the support body matrix 130 are pressed, the space for the fiber to enter is 0.5mm on one side and 1mm on both sides of the protrusion 121 of the support body male material 120. The hot air blowing treatment is carried out under the conditions of temperature 160℃, wind speed 6m/second, and blowing time 6 seconds.

(Implementation Example 6)

The nonwoven fabric sample A6 of Example 6 was prepared in the same manner as Example 1 except that Sumikaflex 730 ((trade name, manufactured by Sumika Chemtex Co., Ltd.) ethylene-vinyl acetate copolymer emulsion) was used as the adhesive.

(Implementation Example 7)

The nonwoven fabric sample A7 of Example 7 was prepared in the same manner as Example 1, except that Cariflex IR0401 latex ((trade name, manufactured by Clayton Corporation) special isoprene latex, aqueous emulsion (solid content/water weight ratio = 63/37)) was used as the adhesive.

(Implementation Example 8)

A fiber web (hereinafter referred to as "1.2 dtex fiber web") having a core component of PET and a sheath component of PE and composed of 1.2 dtex thermoplastic fibers including concentric core-sheath type composite fibers (core-sheath ratio 50 mass %: 50 mass %) as shown in Table 1, and a fiber web (hereinafter referred to as "2.0 dtex fiber web") having a core component of PET and a sheath component of PE and composed of 2.0 dtex thermoplastic fibers including concentric core-sheath type composite fibers (core-sheath ratio 50 mass %: 50 mass %) as shown in Table 1 were prepared. Using these fiber webs, a laminated web was prepared in which the fiber webs were laminated at a mass ratio of 1.2 dtex fiber web: 2.0 dtex fiber web = 2:3. The laminated web was used to perform a heat treatment step to produce a raw nonwoven fabric. The heat treatment step was performed by blowing hot air at a temperature of 140°C, a wind speed of 6 m/s, and a blowing time of 6 seconds. In the heat treatment step, the heat treatment was performed in a manner such that the 2.0 dtex fiber web side of the laminated web became the blowing side. The 1.2 dtex fiber web side of the obtained raw nonwoven fabric was used as the adhesive coating side, and the adhesive coating liquid was sprayed in the same manner as in Example 1 to produce the nonwoven fabric sample A8 of Example 8.

(Comparative example 1)

Using core-sheath type thermoplastic composite fibers of fiber diameters shown in Table 2, a nonwoven fabric with a concave-convex shape described in Example 1 of Patent Document 2 was produced by hot air method. The basis weight is shown in Table 2. The nonwoven fabric was not coated with adhesive coating liquid and was directly used as nonwoven fabric sample C1 of Comparative Example 1.

(Comparative example 2)

Using core-sheath type thermoplastic composite fibers with fiber diameters shown in Table 2, a flat nonwoven fabric without bumps and depressions was produced by hot air method. The basis weight is shown in Table 2. The nonwoven fabric was not coated with adhesive coating liquid and was directly used as nonwoven fabric sample C2 of Comparative Example 2.

(Comparative example 3)

The fiber (PET) having the fiber diameter shown in Table 2 was used to produce the resin bonded nonwoven fabric described in Example 1 of Patent Document 1. During the production, the adhesive coating liquid (BONKOTE AB-886 coating liquid) used in Example 1 was used as the resin bonded coating liquid for spraying. The coating amount was 16.6 g/m ² . The resin bonded nonwoven fabric was used as the nonwoven fabric sample C3 of Comparative Example 2.

The nonwoven fabric sample C3 has no concavo-convex shape but has a flat shape.

(Comparative example 4)

The nonwoven fabric placed inside the front sheet was taken out from the M-size diaper of Procter & Gamble Company (purchased in May 2018) sold in China. The nonwoven fabric sample was placed in a beaker of 100 mL of ethyl acetate and stirred for 30 minutes. The nonwoven fabric sample was taken out and dried. The nonwoven fabric thus obtained was used as the nonwoven fabric sample C4 of Comparative Example 4.

The nonwoven fabric sample C4 has no concavo-convex shape but has a flat shape.

(Comparative example 5)

Based on Example 1 described in Japanese Patent Publication No. 2012-136803, a nonwoven fabric sample C5 of Comparative Example 5 was prepared.

(Comparative example 6)

The nonwoven fabric sample C6 of Comparative Example 6 was prepared in the same manner as Example 5 except that the adhesive was not applied.

(Comparative Example 7)

The nonwoven fabric sample C7 of Comparative Example 7 was prepared in the same manner as Example 1 except that the adhesive was not applied.

(Comparative example 8)

The nonwoven fabric sample C8 of Comparative Example 8 was prepared in the same manner as Example 8 except that the adhesive was not applied.

The above-mentioned examples and comparative examples were subjected to the following measurements (I) to (IX).

(I) Determine the adhesive area ratio and fiber area ratio per unit area when viewing the nonwoven fabric from above

The measurement is carried out based on the above (measurement method of requirement (1)).

(II) Determine the ratio of the mass of the adhesive to the mass of the nonwoven fabric and the ratio of the mass of the fiber to the mass of the nonwoven fabric

The measurement is carried out based on the above (measurement method of requirement (2)).

(III) Determine the presence of adhesive at the fiber intersections

Based on the above (method for measuring the existence rate of adhesive at fiber intersections on either the front or back side of the nonwoven fabric when viewed from above) and (method for measuring the existence rate of adhesive at fiber intersections in the center of the thickness of the nonwoven fabric), the existence rate of adhesive at fiber intersections is calculated based on the above formula (S1). That is, the existence rate of adhesive at fiber intersections on the first and second sides of the nonwoven fabric when viewed from above and the existence rate of adhesive at fiber intersections in the center of the thickness of the nonwoven fabric are measured and calculated.

(IV) Determine the coverage rate and coverage area of the adhesive

The adhesive coverage area (Ka) and coverage rate (K) of the adhesive on the first and second surfaces of the nonwoven fabric are measured on the first and second surfaces using the above-mentioned (method for measuring the presence rate of the adhesive at the fiber intersections on either the front or back side of the nonwoven fabric when viewed from above).

(V) Determination of the longitudinal orientation of nonwoven fabrics

The measurement is based on the above (method for measuring the longitudinal orientation of nonwoven fabrics).

(VI) Determination of adhesive area on the wall of the convex-concave non-woven fabric

The measurement is performed based on the above (confirmation method of the presence of adhesive on the wall).

(VII) Texture: Measurement method of MMD (mean friction coefficient variation)

Use an automatic surface testing machine (KES-FB4-A-SE: manufactured by Jiaduo Technology Co., Ltd.) to measure the variation of the average friction coefficient (MMD) of the non-woven surface. Prepare a 100mm×100mm test piece and place it on a smooth metal test table. Press the contact surface of the contact piece to the test piece with a force of 49cN, and move the test piece horizontally for 2cm at a fixed speed of 0.1cm/sec. Apply a uniaxial tension of 19.6cN/cm to the test piece. The contact piece is 20 piano wires with a diameter of 0.5mm arranged side by side and bent into a U shape with a width of 10mm. Use a lead hammer to press the contact surface to the test piece with a force of 49cN. The measured value of the average deviation of the friction coefficient is expressed by the MMD value. The measurement was performed on both MD and CD, and the average value was calculated using the following formula (S2), which was used as the average deviation of the friction coefficient.

Average deviation of friction coefficient = {(MMD _MD ² +MMD _CD ² )/2} ^1/2 (S2)

The average deviation of the friction coefficient indicates the degree of friction unevenness. The smaller the value, the smoother the feel.

(VIII) Determination method of compression recovery rate and (IX) recovery amount

The compression recovery rate is measured under the assumption that the product is compressed by the human body and is compressed when sealed in a packaging bag. The nonwoven fabric to be measured is frozen with liquid nitrogen, cut with a razor, and cut into 10cm×10cm pieces to make a test sample. The thickness of the test sample is measured at a load of 50Pa using a laser thickness gauge. Three locations are measured, and the average value is used as the apparent thickness of the nonwoven fabric before compression.

Then, the nonwoven fabric of the test sample is compressed to 0.7mm with a load of 20kPa. At this time, the nonwoven fabric is compressed in a manner such as inserting a spacer so that it becomes 0.7mm. After the compressed state is maintained at 50℃ for 24 hours, the compressed state is released and placed at 25℃ for 30 minutes. Then, the thickness is measured at a load of 50Pa using a laser thickness gauge. Three locations are measured and the average value is used as the measurement data to obtain the "apparent thickness of the nonwoven fabric after the compression is released".

Finally, the recovery rate of nonwoven fabrics depending on their thickness is calculated using the following formula.

"Recovery rate of nonwoven fabric after compression release depending on thickness [%]"

= "Apparent thickness of nonwoven fabric after compression (mm) - 0.7" ÷ "Apparent thickness of nonwoven fabric before compression (mm)" × 100

In addition, the thickness recovered after being compressed to 0.7mm (the apparent thickness of the nonwoven fabric after compression is released (mm) - 0.7) is taken as the recovery amount.

[Table 1]

[Table 2]

As shown in the results of (VII) texture, (VIII) compression recovery rate and (IX) recovery amount in Tables 3 and 4, the nonwoven fabric samples of Examples 1 to 5 show very good texture equivalent to the nonwoven fabric samples of Comparative Examples 1, 2 and 6 to 8 without adhesive. On the other hand, in terms of thickness recovery represented by compression recovery rate and recovery amount, the nonwoven fabric samples of Comparative Examples 1, 2 and 6 to 8 are superior. In particular, the nonwoven fabric sample of Example 1 showed a very good texture equivalent to the nonwoven fabric of Comparative Example 7 in which the same nonwoven fabric raw material did not contain an adhesive, and showed excellent thickness recovery compared to the nonwoven fabric sample of Comparative Example 7, with a compression recovery rate of about 1.72 times and a recovery amount of about 1.9 times. The nonwoven fabric sample of Example 5 showed a texture equivalent to the nonwoven fabric of Comparative Example 6 in which the same nonwoven fabric raw material did not contain an adhesive, and showed excellent thickness recovery compared to the nonwoven fabric sample of Comparative Example 6, with a compression recovery rate of about 1.4 times and a recovery amount of about 1.4 times. Furthermore, in the flat nonwoven fabric sample of Example 2, the initial thickness is smaller, and accordingly, a higher compression recovery rate value is obtained to a certain extent, but the recovery amount value is smaller, and it fails to show a larger thickness recovery behavior like the nonwoven fabric samples of Examples 1 to 5.

In addition, the nonwoven fabric samples of Examples 1 to 5 show a compression recovery rate equal to or higher than that of the nonwoven fabric samples of Comparative Examples 3 to 5 containing adhesives. The recovery amount is more than 3 times that of the nonwoven fabric samples of Comparative Examples 3 to 5, and the texture is also superior to that of the nonwoven fabric samples of Comparative Examples 3 to 5.

In addition, the nonwoven fabric samples of Examples 6 and 7 changed the adhesive in the nonwoven fabric sample of Example 1. Even so, they still maintained sufficient texture, and compared with the nonwoven fabric samples of Comparative Examples 1 to 8, the compression recovery rate and recovery amount were higher, showing excellent thickness recovery.

In addition, the apparent thickness of the nonwoven fabric of Example 8 is extremely thin, 1.5 mm, and has no bumps, but it maintains a good texture compared to the nonwoven fabric samples of Comparative Examples 3 to 5 containing adhesives. Furthermore, the nonwoven fabric of Example 8 shows a higher compression recovery rate than the nonwoven fabric of Comparative Example 8 which does not contain an adhesive in the same nonwoven fabric raw material.

Furthermore, in the measurement of MMD (variation of mean friction coefficient) which indicates the texture, the terminal for measuring friction is subjected to irregular adhesion force from the adhesive on the fiber surface and the variation of mean friction coefficient becomes larger. Also, when the fibers are firmly bonded and hardened by the adhesive, the terminal will not flexibly deform when subjected to the friction force of the non-woven surface, and the friction force on the terminal will vary. The resulting minor phenomena such as fiber hardening or stickiness show a large difference in texture. Even if the difference in MMD values shown in Table 3 and Table 4 is small, there will be a significant difference in texture as a delicate skin surface.

As described above, the nonwoven fabric samples of Examples 1 to 8 can achieve excellent texture and thickness recovery that cannot be obtained in the nonwoven fabric samples of Comparative Examples 1 to 8.

In the above-mentioned embodiments, in terms of compression recovery rate and recovery amount, embodiments 1 and 4 show better effects than embodiments 2, 3, and 5.

Compared with Example 2, Examples 1 and 4 have a suppressed basis weight and a smaller fiber amount. Therefore, it is believed that the longitudinal orientation degree becomes higher, and the ratio of the adhesive that can be attached to the fiber with thickness direction components also becomes larger, and the above excellent effect can be obtained.

The numerical value limits or ranges described in this specification include the values at the ends of the limits or ranges. In addition, for the sake of clarity, all values and partial ranges within the numerical value limits or ranges are explicitly included.

Singular words used in this manual have the meaning of "1 or plural".

It is clear that various modifications and variations can be made to the present invention based on the above suggestions. Therefore, it is hoped that it will be understood that within the scope of the attached patent application, the present invention can be implemented by methods other than the methods specifically described in this specification.

All the above patents and other references are incorporated into this manual by reference so that the contents are the same when detailed descriptions are given.

The present invention has been described together with its implementation methods and examples, but unless otherwise specified by the inventor, the present invention is not limited in any detail of the description and is considered to be broadly interpreted without violating the spirit and scope of the invention as shown in the attached patent claims.

This case claims priority based on the patent application No. 2020-070611 filed in Japan on April 9, 2020. This patent application is hereby incorporated by reference and its contents are incorporated into this article as part of the description of this specification.

1A: Page 1

1B: Side 2

80:Nonwoven fabric

81,82: Outer surface fiber layer

81A: 1st outer surface fiber layer

81B: Second outer surface fiber layer

83: Wall

83A: 1st connection

83B: Second connection part

88,89: concave part

Claims (9)

A nonwoven fabric having an adhesive and thermoplastic fibers, and having fusion points between the fibers, having concave-convex shapes on both sides of the nonwoven fabric, having fiber intersections where fibers having thickness direction components intersect with other fibers at the center of the thickness of the nonwoven fabric, and having the adhesive at the fiber intersections, and the existence rate of the adhesive at the fiber intersections when the nonwoven fabric is viewed from above is compared with the existence rate of the adhesive at one of the front and back surfaces of the nonwoven fabric. side, and is larger than 10 percentage points on the opposite side, and the above-mentioned adhesive meets one or both of the following requirements (1) and (2): (1) when the above-mentioned non-woven fabric is viewed from above, the area ratio of the above-mentioned adhesive per unit area is less than the area ratio of the fiber not covered by the above-mentioned adhesive; (2) the ratio of the mass of the above-mentioned adhesive to the mass of the above-mentioned non-woven fabric is less than the ratio of the mass of the fiber to the mass of the above-mentioned non-woven fabric by more than 65 percentage points. A nonwoven fabric having an adhesive and thermoplastic fibers, and having fusion points between the fibers, wherein the longitudinal orientation of the nonwoven fabric is 60% or more, and at the center of the thickness of the nonwoven fabric, there is a fiber intersection where fibers having thickness direction components intersect with other fibers, and the adhesive is present at the fiber intersection, and the presence rate of the adhesive at the fiber intersection when the nonwoven fabric is viewed from above is greater than that of the adhesive at one of the front and back surfaces of the nonwoven fabric. side, and is 10 percentage points larger on the opposite side, and the above-mentioned adhesive meets one or both of the following requirements (1) and (2): (1) when the above-mentioned nonwoven fabric is viewed from above, the area ratio of the above-mentioned adhesive per unit area is less than the area ratio of the fiber not covered by the above-mentioned adhesive; (2) the ratio of the mass of the above-mentioned adhesive to the mass of the above-mentioned nonwoven fabric is 65 percentage points or more smaller than the ratio of the mass of the fiber to the mass of the above-mentioned nonwoven fabric. For example, the nonwoven fabric of claim 1 or 2, wherein when the nonwoven fabric is viewed from above, the presence rate of the adhesive at the intersection of fibers on at least one of the front and back sides of the nonwoven fabric is 5% or more and 60% or less per unit area of the nonwoven fabric. For nonwoven fabrics as claimed in claim 1 or 2, in which, in a cross section through the center of the thickness of the nonwoven fabric, the presence rate of the adhesive at the intersection of the fibers in the center of the thickness is not less than 10% and not more than 60% per unit area of the nonwoven fabric. For nonwoven fabrics as claimed in claim 1 or 2, the mass of the above-mentioned adhesive is not less than 1% and not more than 20% of the mass of the above-mentioned nonwoven fabrics. As in claim 1 or 2, the nonwoven fabric comprises composite fibers having two or more resin components with different melting points. As in claim 1 or 2, the nonwoven fabric has a concave-convex shape in the thickness direction of the nonwoven fabric, and the concave-convex shape has a convex part, a concave part, and a wall part connecting the convex part and the concave part. As in claim 7, the nonwoven fabric, wherein the adhesive is present in the wall portion. An absorbent article having a nonwoven fabric as claimed in any one of claims 1 to 8.