CN215689118U

CN215689118U - Hot-air nonwoven fabric for absorbent article

Info

Publication number: CN215689118U
Application number: CN201890001448.7U
Authority: CN
Inventors: 小森康浩; 寒川裕太; 种市祥一
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2018-09-07
Filing date: 2018-09-07
Publication date: 2022-02-01
Anticipated expiration: 2028-09-07
Also published as: TWI711437B; GB201918330D0; RU2733362C1; JPWO2020049747A1; GB2581560A; DE112018003388T5; KR102177357B1; JP6667047B1; KR20200045461A; GB2581560B; TW202023501A; WO2020049747A1

Abstract

A warm-air nonwoven fabric (10) for an absorbent article, which is a warm-air nonwoven fabric (10) formed by laminating 2 or more fiber layers (1, 2), has at least 1 fiber layer (8) comprising thermoplastic fibers and having a fiber block section (7).

Description

Hot-air nonwoven fabric for absorbent article

Technical Field

The present invention relates to a hot-air nonwoven fabric for an absorbent article.

Background

The hot air nonwoven fabric is formed by blowing hot air in a hot air manner to thermally fuse the intersections of the fibers, and therefore, the hot air nonwoven fabric is easily formed to be relatively thick, and the touch of the skin is good. Therefore, the absorbent article is often used as a component member. Various proposals have been made so far regarding such a through-air nonwoven fabric for absorbent articles.

For example, patent document 1 describes the following hot air nonwoven fabric: from the viewpoint of providing aesthetic appearance by design without impairing the texture, the difference between the thickness of the part having small fiber mass and the thickness of the part having no small fiber mass under a pressure of 7.64kPa is set to 1mm or less. As a method for producing the hot air nonwoven fabric, the following is described: the prepared nonwoven fabric obtained by the hot air blowing treatment is subjected to calendering. Patent document 2 describes an absorbent article including a nonwoven fabric having thermoplastic synthetic fibers and organic cotton fibers. In the nonwoven fabric, the organic cotton fibers are arranged to form a plurality of fiber blocks. The organic cotton fibers are not thermally fused but remain in the nonwoven fabric by entanglement of the fibers with each other.

Patent document 3 describes the following: from the viewpoint of improving the texture of the nonwoven fabric, the completed nonwoven fabric is placed between a pair of rollers and subjected to a pressure treatment at a specific line pressure and temperature.

Patent document 4 describes the following processing method: the fiber sheet wound in a roll shape is wound out, hot air is blown by hot air, and calendering processing is performed by specific linear pressure.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-151774

Patent document 2: japanese patent laid-open publication No. 2017-202265

Patent document 3: japanese laid-open patent publication No. 60-126365

Patent document 4: japanese patent laid-open publication No. 2006-299480

SUMMERY OF THE UTILITY MODEL

The utility model provides a hot-air non-woven fabric for an absorbent article, which is a hot-air non-woven fabric laminated with more than 2 fiber layers and has at least 1 fiber layer containing thermoplastic fibers and having a fiber block part.

Further, the present invention provides a method for producing a hot-air nonwoven fabric for an absorbent article, comprising: a fiber opening step of forming a fiber web by performing a fiber opening process on thermoplastic fibers a plurality of times; a through-air nonwoven fabric forming step of forming a laminated web by laminating a plurality of single-layer webs obtained in the opening step, and subjecting the laminated web to through-air processing using through-air to obtain a through-air nonwoven fabric; and a calendering step of processing one or more selected from the group consisting of the single-layer web, the laminated web, and the through-air nonwoven fabric using a pair of calender rolls.

The above and other features and advantages of the present invention will become apparent from the following description, appropriately referring to the accompanying drawings.

Drawings

Fig. 1 is a cross-sectional view schematically showing a preferred embodiment of the air-through nonwoven fabric for an absorbent article of the present invention.

FIG. 2 is a schematic configuration diagram showing a preferred embodiment of a method and an apparatus for producing a nonwoven fabric of the present invention.

Fig. 3 is a schematic configuration diagram showing another preferred embodiment of a heat treatment section for performing the hot air process in the present embodiment.

Detailed Description

The present invention relates to a hot air nonwoven fabric for an absorbent article having excellent bulk and soft texture and having a pattern.

In the production process of the air-through nonwoven fabric, when fibers are opened and made into a web, the fibers may be entangled with each other to partially form fiber lumps. In particular, the smaller the fiber diameter, the more likely the above-mentioned fiber cake is to be generated. When the fiber mass is subjected to the hot air processing step directly with hot air, the fibers are thermally fused to each other and are cured.

In contrast, conventionally, as described in patent documents 1, 3, and 4, a finished nonwoven fabric is subjected to calendering to reduce a hard feeling. However, since the calendering is a treatment of pressing the hot-air nonwoven fabric between a pair of rollers, the thickness of the hot-air nonwoven fabric after pressing becomes thin, there is room for improvement in bulkiness. Even when the nonwoven fabrics described in patent documents 1, 3 and 4 are subjected to hot air treatment after calendering, there is still a limit to the recovery of the thickness of the nonwoven fabric once flattened, and there is still room for further improvement. In this regard, patent document 3 does not suggest the recovery of the bulkiness.

In the air-through nonwoven fabric for an absorbent article, from the viewpoint of the absorbency and cushioning properties of the absorbent article, it is strongly desired to have both bulkiness and a soft texture and to have both of them excellent.

In contrast, the hot air nonwoven fabric for an absorbent article of the present invention has excellent bulk and soft texture, and has a pattern. Further, according to the manufacturing method of the present invention, the air-through nonwoven fabric for an absorbent article can be manufactured with high accuracy.

Hereinafter, a hot air nonwoven fabric for an absorbent article according to the present invention will be described with reference to the drawings.

The air-through nonwoven fabric for absorbent articles of the present invention can be applied to various absorbent articles worn on the body to absorb body fluids, and can be applied to various components such as a topsheet in the absorbent articles.

In the present invention, unless otherwise specified, the side in contact with the human body is referred to as the skin surface side or the skin contact surface side or the surface side, and the opposite side is referred to as the non-skin surface side or the non-skin contact surface side or the back surface side.

In the present invention, the "through-air nonwoven fabric" refers to a nonwoven fabric in which heat-fusible fibers are heat-fused and integrated at intersections. The hot air method is used for producing the nonwoven fabric. The hot air method is a method in which hot air is blown through fiber webs including heat-fusible fibers to fuse the fiber webs at their intersections to form a nonwoven fabric.

The air-through nonwoven fabric for an absorbent article of the present invention is an air-through nonwoven fabric in which 2 or more fiber layers are laminated. The number of stacked fiber layers may be 2 or 3 or more. The air-through nonwoven fabric for an absorbent article of the present invention has 2 or more layers, and thus can form a bulky nonwoven fabric beyond the manufacturing constraints as compared with the case where a nonwoven fabric is formed of 1 layer.

Fig. 1 shows a through-air nonwoven fabric 10 for an absorbent article (hereinafter referred to as "nonwoven fabric 10") in which 2 fiber layers (fiber layer 1 and fiber layer 2) are laminated, as a preferred embodiment of the through-air nonwoven fabric for an absorbent article of the present invention. The

fiber layers

1 and 2 include heat-fusible fibers, and the contact surfaces of the two layers are joined over the entire range by the fusion of the heat-fusible fibers. Therefore, the nonwoven fabric 10 does not have a region where the fiber layer 1 is separated from the fiber layer 2. That is, the nonwoven fabric 10 is a 1-sheet body in which the 2 layers are integrated.

The nonwoven fabric of the present invention may have various surface shapes such as uneven surfaces, but it is preferable that both

surfaces

10A and 10B (the surface of the fiber layer 1 and the surface of the fiber layer 2) are flat as in the nonwoven fabric 10 of the present embodiment shown in fig. 1. The nonwoven fabric 10 is a laminate of a plurality of fiber layers and has a flat shape on both sides, and therefore has both a smooth feeling and a cushioning feeling on the surface and is excellent. The flat shape means that the difference in thickness between the concave portions and the convex portions on the surface of the nonwoven fabric is within 1 mm. Specifically, the nonwoven fabric was cut in the thickness direction using a razor blade, and a photograph of the cross section was taken using a microscope (VHX-900, manufactured by keyence corporation). In the photograph, the thickness of the convex portion, which is the uppermost portion of the upper surface of the nonwoven fabric, and the thickness of the concave portion, which is the lowermost portion of the upper surface of the nonwoven fabric, were measured, and the difference in thickness was calculated. Average 3 points.

The nonwoven fabric 10 has at least 1 fiber layer 8 having the fiber block portion 7. Hereinafter, the fiber layer 8 having the fiber block portion 7 is referred to as a fiber block layer 8. In fig. 1, the fiber bulk layer 8 is disposed on the fiber layer 1.

In the present invention, the "fiber mass portion" refers to a portion of a knot (a clew) formed by intertwining fibers in a fiber layer. In the fiber block portion, the density of the fibers is higher than that of the peripheral portion in the same fiber layer, and the fibers are visually recognized as a block (granular shape) having a higher density (lightness) of the color (mainly white) of the fibers than that of the peripheral portion. The shape of the fiber block portion is not particularly limited. In the present invention, the fiber block portion has a flat shape flattened in the thickness direction of the nonwoven fabric in a cross section in the thickness direction of the nonwoven fabric, and preferably has a structure in which the surface of the fiber block portion on the surface side of the nonwoven fabric is smooth. This makes the nonwoven fabric surface corresponding to the position where the fiber block portion 7 is present smooth, and the nonwoven fabric 10 can be perceived to have a more excellent surface texture.

The "fiber block layer 8" is a layer having 1 or more fiber block portions. In the fiber block layer 8, the fiber block portions 7 are not necessarily filled, and are preferably arranged in a dispersed manner.

The fiber block layer 8 is not limited to the case where it is only located on the fiber layer 1 as shown in fig. 1, but may be located on the fiber layer 2 instead of the fiber layer 1, or may be located on both layers. From the viewpoint of soft skin feel, it is preferably located in either layer. In view of enhancing the visual effect obtained by the pattern of the fiber block portions 7 when the nonwoven fabric 10 is viewed in plan view, it is preferable that the two layers have the fiber block layers 8. Thus, the pattern formed by the fiber block portions 7 is not only seen in the planar direction of the nonwoven fabric 10 but also in the thickness direction, and the pattern having a depth is seen by changing the density of the fiber block portions 7 seen in the thickness direction as the lower layer side becomes thinner. When the fiber layer 1 and the fiber layer 2 both have the fiber block layer 8, the fiber block portion 7 of the fiber layer 1 and the fiber block portion 7 of the fiber layer 2 are preferably arranged so as not to overlap in the thickness direction. The fiber block layer 8 may be disposed on the entire fiber layer (the fiber layer 1 or the fiber layer 2) on which the fiber block layer 8 is disposed, or may be disposed on a part thereof.

As described above, the nonwoven fabric 10 is obtained by fusing the fibers at the layer interface to each other over the entire range where the fiber layers 1 and 2 are in contact with each other, and integrating them. Therefore, even though the nonwoven fabric 10 includes the fiber mass layer 8 having the fiber mass portion 7, the nonwoven fabric 10 obtained by integrating a plurality of fiber layers as a whole at the layer interface has a thickness as a whole, and is excellent in bulkiness and soft touch to the skin. In addition, when the nonwoven fabric 10 is viewed in plan, the pattern is provided by the difference in color density between the portion having the fiber block portion and the portion having no fiber block portion. The pattern formed by the fiber block portions 7, particularly the pattern formed by the fiber block portions 7 having a flat thickness, provides the nonwoven fabric 10 with aesthetic qualities.

The nonwoven fabric 10 of the present embodiment preferably has fine fibers and coarse fibers having a fiber diameter larger than that of the fine fibers, and the fiber diameter of the fine fibers is 1dtex or more and 2.2dtex or less. This improves the soft touch of the nonwoven fabric with the fine fibers, and improves bulkiness with the coarse fibers. Further, the presence of coarse fibers is also preferable because it contributes to improvement in thickness recovery of the nonwoven fabric after pressing.

Further, the fiber block layer 8 preferably contains the fine fibers. In this case, the fine fibers may be included in the fiber block portion 7, or may be included in a portion other than the fiber block portion 7. This alleviates the feeling of stiffness around the fiber block 7, which is felt when the nonwoven fabric 10 is touched, by the presence of the fine fibers. In this case, the nonwoven fabric 10 preferably includes: the fiber layer 1 having the fiber mass layer 8 containing the fine fibers is disposed toward the skin contact surface side of the absorbent article.

From the viewpoint of improving the soft touch of the nonwoven fabric 10, the fiber diameter of the fine fibers is preferably 2dtex or less, and more preferably 1.5dtex or less. In addition, from the viewpoint of the spinnability of a carding machine for producing a nonwoven fabric, the fiber diameter of the fine fiber is preferably 1dtex or more, and more preferably 1.2dtex or more. Specifically, the fiber diameter of the fine fiber is preferably 1dtex or more and 2dtex or less, and more preferably 1.2dtex or more and 1.5dtex or less.

The content of the fine fibers in the fiber mass layer 8 is preferably 50% by mass or more, more preferably 80% by mass or more, and further preferably 100% by mass, in terms of the mass ratio, from the viewpoint of improving the soft touch of the nonwoven fabric 10.

The nonwoven fabric 10 of the present embodiment preferably has at least 1 fiber layer 9 (hereinafter referred to as a non-fiber-block layer 9) having no fiber block portion 7, in addition to the fiber-block layer 8. Examples of the form include the following: as shown in fig. 1, the fiber layer 1 is a fiber block layer 8, and the fiber layer 2 is a non-fiber block layer 9.

When the nonwoven fabric 10 has the fiber bulk layer 8 and the non-fiber bulk layer 9, it is preferable that the nonwoven fabric has coarse fibers and fine fibers having a fiber diameter smaller than the coarse fibers, and the fiber diameter of the coarse fibers is more than 2.2dtex and not more than 7 dtex. The fiber diameter of the fine fiber is preferably within the above range. This is preferable because the soft texture of the nonwoven fabric can be improved by the fine fibers, and the bulkiness can be improved by the coarse fibers, which contributes to the improvement of the thickness recovery of the nonwoven fabric after pressurization.

Further, the non-fiber bulk layer 9 preferably contains the above-described coarse fibers. By including the coarse fibers in the non-fibrous bulk layer 9, bulkiness can be improved and a cushion feeling can be imparted. In this case, the nonwoven fabric 10 preferably includes: the fibrous layer 2 having the non-fibrous bulk layer 9 containing coarse fibers is disposed toward the non-skin contact surface side of the absorbent article.

From the viewpoint of improving bulkiness and compression recovery of the nonwoven fabric 10, the fiber diameter of the coarse fibers is preferably more than 2.2dtex, and more preferably 4.4dtex or more. Further, the fiber diameter of the coarse fibers is preferably 5.5dtex or less, more preferably 5dtex or less, from the viewpoint of the texture on the fiber block layer side. Specifically, the fiber diameter of the crude fiber is preferably more than 2.2dtex and not more than 5.5dtex, and more preferably 4.4dtex to 5 dtex.

The content of the coarse fibers in the non-fiber bulk layer 9 is preferably 50 mass% or more, more preferably 80 mass% or more, and further preferably 100 mass% in terms of a mass ratio, from the viewpoint of improving bulkiness and compression recovery of the nonwoven fabric 10.

In addition, from the viewpoint of improving the soft touch of the nonwoven fabric 10, the content of the coarse fibers in the fiber bulk layer 8 is preferably 50% by mass or less, more preferably 30% by mass or less, and still more preferably 10% by mass or less, in terms of a mass ratio.

(method of measuring fiber diameters of Fine fiber and coarse fiber, method of measuring content of Fine fiber in the fiber bulk layer 8, and method of measuring content of coarse fiber in the non-fiber bulk layer 9)

Using a scanning electron microscope (JCM-5100 manufactured by japan electronics), 3 positions of the fiber bulk layer side and the surface side of the non-fiber bulk layer were observed at 100 magnifications from arbitrary positions of the nonwoven fabric.

Fiber diameter: determination of 1mm²Fiber diameter in the area range. For the measurement of the fiber diameter, 20 points of each different fiber were measured at 1 position, and the average value was defined as the fiber diameter. The width of variation in fiber diameter of the nonwoven fabric for absorbent articles is usually slightly different to such an extent that it is difficult to confirm even when observed with the scanning electron microscope. For example, the width of the variation in fiber diameter is generally about 6% from the fiber specification. Therefore, the average value of the 20 points measured as described above can be used as the fiber diameter.

Fiber content: 1mm of previous magnification observation²An OHP film was placed on the inner photograph, and the film was blackened according to the fiber diameter. The sheet was subjected to image analysis processing using image analysis software (Nexus New quie). The area is determined by performing binarization processing. The area of each fiber was measured, and the ratio was defined as the content of each fiber.

(method of sampling measuring Member)

In the case where the measurement is performed by taking out a constituent member (for example, a surface material) to be measured from the absorbent article and performing evaluation measurement, the measurement can be performed by the following method. That is, when this constituent member is fixed to another constituent member by an adhesive or the like, the adhesive is cooled by liquid nitrogen to make the constituent member easily peelable. When a component is fixed to another component by welding or the like, the component is peeled off by hand, or the welded portion is cut off by a cutting blade or the like and then the component is peeled off. The method is also applicable to other measurement methods.

In the nonwoven fabric 10, the average fiber diameter of the non-fiber bulk layer 9 is preferably larger than that of the fiber bulk layer 8. Thus, the fiber bulk layer 8 serves as a layer for improving the soft texture of the nonwoven fabric 10, and the non-fiber bulk layer 9 serves as a layer for improving the bulk and thickness recovery of the nonwoven fabric 10. As a result, the fiber bulk layer 8 and the non-fiber bulk layer 9 can share functions in units of layers with respect to the nonwoven fabric 10, and the two layers can cooperate in the thickness direction to further improve the texture of the entire nonwoven fabric 10. In this regard, the nonwoven fabric 10 preferably has the fine fibers and the coarse fibers, and the fiber bulk layer 8 contains the fine fibers in a form that can more clearly exhibit the above-described action. From the same viewpoint, it is more preferable that the non-fiber bulk layer 9 contains the coarse fibers.

From the viewpoint of the above-described function assignment of the nonwoven fabric, the difference V3 (V1-V2) between the average fiber diameter V1 of the non-fiber bulk layer 9 and the average fiber diameter V2 of the fiber bulk layer 8 is preferably more than 0dtex, more preferably 2.2dtex or more, and further preferably 3dtex or more. From the same viewpoint as described above, the difference V3 is preferably 5.6dtex or less, more preferably 4dtex or less, and further preferably 3.5dtex or less. Specifically, the difference V3 is preferably more than 0dtex and not more than 5.6dtex, more preferably 2.2dtex to 4dtex, and still more preferably 3dtex to 3.5 dtex.

(method of measuring average fiber diameter of fiber bulk layer 8 and non-fiber bulk layer 9)

The fiber diameters obtained based on the above (method of measuring the fiber diameters of the fine fibers and the coarse fibers, method of measuring the content of the fine fibers in the fiber bulk layer 8, and method of measuring the content of the coarse fibers in the non-fiber bulk layer 9) are multiplied by the content ratio, and the sum is defined as the average fiber diameter of each layer.

In the nonwoven fabric 10, the basis weight of the non-fiber bulk layer 9 is preferably larger than that of the fiber bulk layer 8. Thus, the non-fiber block layer 9 is bulkier than the fiber block layer 8, and the stiff feeling by the fiber block portion 7 is less likely to be perceived. Further, the bulk of the non-fiber bulk layer 9 can function to improve the cushioning property of the entire nonwoven fabric 10, and the stress applied to the skin by the fiber bulk portion 7 when the fiber bulk layer 8 is pushed flat in the thickness direction can be further reduced, thereby further improving the favorable texture. The nonwoven fabric 10 preferably has the fine fibers and the coarse fibers, the fiber bulk layer 8 contains the fine fibers, and the difference in basis weight is preferable because the above-described effect can be more clearly exhibited. From the same viewpoint, it is more preferable that the non-fiber bulk layer 9 contains the coarse fibers. Further, the nonwoven fabric 10 preferably has an average fiber diameter of the non-fiber bulk layer 9 larger than that of the fiber bulk layer 8.

From the viewpoint of improving the cushioning property and the good texture of the entire nonwoven fabric, the difference Y3 (Y1-Y2) between the basis weight Y1 of the non-fiber bulk layer 9 and the basis weight Y2 of the fiber bulk layer 8 is preferably more than 0g/m²More preferably 3g/m²Above, more preferably 5g/m²The above. Further, the difference Y3 is preferably 20g/m from the viewpoint of improving texture²Hereinafter, more preferably 15g/m²Hereinafter, it is more preferably 10g/m²The following. Specifically, the difference Y3 is preferably more than 0g/m²And 20g/m²Hereinafter, it is more preferably 3g/m²Above 15g/m²Hereinafter, it is more preferably 5g/m²Above 10g/m²The following.

(method of measuring basis weights of fiber bulk layer 8 and non-fiber bulk layer 9)

1) The mass of the nonwoven fabric to be measured was measured at 1m²The obtained value was converted as a whole basis weight.

The mass (W) of the nonwoven fabric to be measured was measured, and the total basis weight (W) was calculated from the following equation.

W＝(1000000/LMD/LCD)w＝25w

LMD: the length of the nonwoven fabric to be measured in the MD direction was 250mm

LCD: the length of the nonwoven fabric to be measured in the CD direction was 160mm

If the sample is collected from the product without the above-mentioned size, the sample is cut within the range where the sample can be collected, and then the cut is performed every 1m²And (4) conversion.

2) Basis weight of each layer: carefully peeling off each layer of the nonwoven fabric to be measured, and setting the mass per 1m²The converted value was defined as the basis weight of each layer.

[ Single sheet ]Bit: number of bits]g/m²: round the second decimal place and reserve to the first decimal place.

[ measurement number ] 3 points were measured, and the average value was defined as each basis weight.

In the structure in which 2 or more fiber layers are laminated and integrated, the basis weight of the entire nonwoven fabric 10 is preferably 15g/m from the viewpoint of obtaining excellent bulkiness and soft touch to the skin and providing good texture to the nonwoven fabric 10²Above, more preferably 18g/m²Above, more preferably 20/m²The above. Further, the basis weight of the nonwoven fabric 10 as a whole is preferably 40g/m from the viewpoint of the spinning ability in nonwoven fabric production²Hereinafter, more preferably 30g/m²Hereinafter, it is more preferably 25g/m²The following. Specifically, the basis weight of the nonwoven fabric 10 as a whole is preferably 15g/m²Above 40g/m²Hereinafter, more preferably 18g/m²Above 30g/m²Hereinafter, more preferably 20/m²Above and 25g/m²The following. The basis weight of the entire nonwoven fabric 10 was measured as described above (method of measuring the basis weight of the fiber bulk layer 8 and the non-fiber bulk layer 9).

In the nonwoven fabric 10, when the thickness of the nonwoven fabric 10 measured under a pressure of 7.64kpa at the position where the fiber block portion 7 is arranged is T1, and the thickness of the nonwoven fabric 10 measured under the same pressure at the position where the fiber block portion 7 is not arranged is T2, the smaller the difference T3 between the thicknesses defined by T3 and T1-T2, the harder the nonwoven fabric is felt by the fiber block portion 7. As a result, a cushioning feeling associated with bulkiness achieved by laminating a plurality of fiber layers is easily felt, and a soft touch feeling is easily felt. From this viewpoint, the difference T3 in thickness is preferably 0.4mm or less, more preferably 0.3mm or less, still more preferably 0.2mm or less, and most preferably 0 (zero) mm.

Here, the "position at which the fiber block portion is arranged" refers to a position at which the presence of the fiber block portion 7 is visually recognized in a plane view when viewed from a plane on the pressing side out of the front surface and the back surface of the nonwoven fabric 10 (hereinafter, the same meaning is used in the present specification). The "position where the fiber block portion is not arranged" refers to a position where the presence of the fiber block portion 7 is not visually recognized in the plane of the above-described plan view (hereinafter, the same meaning is used in the present specification).

(method of measuring thickness of nonwoven Fabric under pressure of 7.64 kPa)

The thickness T1 at the position where the fiber mass portion is arranged in the nonwoven fabric and the thickness T2 at the position where the fiber mass portion is not arranged in the nonwoven fabric under the same pressure are measured using a DIAL GAUGE thickness GAUGE (JIS B7503 (1997)), a straight DIAL GAUGE manufactured by PEACOCK corporation, a flat disc with a pressure of 7.64kPa and a probe tip of Φ 5mm, and the difference in thickness defined by T3 to T1-T2 is determined. T1 and T2 were measured at 5 points or more, respectively. Then, the average value of T1 and the average value of T2 were calculated, and the difference between them was calculated as T3. The load of 7.64kpa is a measurement condition set to clarify the presence of the fiber lump portion.

The soft texture of the nonwoven fabric 10 is represented by the value of the average friction coefficient, and a smaller value indicates a more excellent texture. In general, the average friction coefficient of the portion where the fiber block portion 7 is not arranged has a smaller value than that of the portion where the fiber block portion 7 is arranged. However, since the nonwoven fabric 10 of the present embodiment is obtained by laminating and integrating a plurality of fiber layers in the thickness direction, the average friction coefficient is small at the position where the fiber block portion 7 is arranged. From the viewpoint of maintaining a soft skin feel, it is realistic that the average friction coefficient (Q1) of the nonwoven fabric 10 at the position where the fiber mass portion 7 is arranged is preferably 2.5 or less, more preferably 2.4 or less, even more preferably 2.3 or less, and furthermore, 1.6 or more. Specifically, the average friction coefficient (Q1) at the position where the fiber block portion 7 is arranged in the nonwoven fabric 10 is preferably 1.6 or more and 2.5 or less, more preferably 1.6 or more and 2.4 or less, and still more preferably 1.6 or more and 2.3 or less.

From the viewpoint of maintaining a soft skin feel, the difference Q3 (Q1-Q2) between the average friction coefficient Q1 at the position where the fiber mass portion 7 is disposed in the nonwoven fabric 10 and the average friction coefficient Q2 at the position where the fiber mass portion 7 is not disposed in the nonwoven fabric 10 is preferably 0.7 or less, more preferably 0.5 or less, even more preferably 0.32 or less, particularly preferably 0.3 or less, and most preferably 0 (zero).

(method of measuring average Friction coefficient)

The nonwoven fabric to be measured was cut into a 15cm square using a KES-FB4 surface tester manufactured by Gamut technologies, Inc., and the measurement surface was measured in a SENS: 2 × 5, load: the MIU values were measured at the positions where the fiber lumps were located and at the positions where the fiber lumps were not located under the condition of 4.9 kPa. Measurements were performed at 5 or more points in each of 2 orthogonal directions (typically, the MD direction and the CD direction), and the average value of the measurements was calculated. The MIU value is an average friction coefficient, and it is found from the evaluation that the larger the value, the rougher the surface and the worse the texture, and the smaller the value, the smoother the surface and the better the texture.

The fiber block layer 8 is preferably an outermost layer of the nonwoven fabric 10. In this case, the fiber block layer 8 may be present only on one of the front and back surfaces of the nonwoven fabric 10, or the fiber block layer 8 may be present on both of the front and back surfaces of the nonwoven fabric 10. By making the fiber block layer 8 the outermost layer of the nonwoven fabric 10, the visual effect is maximized.

From the viewpoint of maintaining a soft texture of the nonwoven fabric 10, the number of fiber block portions 7 arranged in the nonwoven fabric 10 is preferably 50 or less, more preferably 40 or less, and even more preferably 30 or less, on average per 10cm square area when the front surface and the back surface of the nonwoven fabric 10 are viewed in a plan view (a plan view in a state where the respective fiber layers are laminated). On the other hand, from the viewpoint of imparting a pattern, the number of fiber block portions 7 arranged in the nonwoven fabric 10 is preferably 5 or more, more preferably 10 or more, and further preferably 20 or more, on average per 10cm square area when the front surface and the back surface of the nonwoven fabric 10 are viewed in a plan view (a plan view in a state where the respective fiber layers are laminated). Specifically, the number of the fiber block portions 7 is preferably 5 to 50, more preferably 10 to 40, and further preferably 20 to 30, in average per 10cm square area when the front surface and the back surface of the nonwoven fabric 10 are viewed in a plan view (when the nonwoven fabric is viewed in a state where the fiber layers are stacked).

From the viewpoint of reducing the chance of skin contact with the fiber mass portion 7, the number of fiber mass portions 7 in the fiber layer on the skin surface side of the absorbent article in the stacked fiber layers is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less, on average per 10cm square area when the fiber layer on the skin surface side is viewed in plan. The number of fiber mass portions 7 in the fiber layer to be the skin surface side of the absorbent article is preferably 1 or more. Specifically, the number of fiber mass portions 7 in the fibrous layer on the skin surface side of the absorbent article is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 10, in average per 10cm square area when the fibrous layer on the skin surface side is viewed in plan.

Further, from the viewpoint of forming a pattern having depth, the number of fiber mass portions 7 arranged in the fiber layer to be the non-skin surface side of the absorbent article among the 2 stacked layers is preferably 3 or more, more preferably 8 or more, and further preferably 15 or more per 10cm square area in a plan view of the fiber layer to be the non-skin surface side.

From the viewpoint of soft texture of the nonwoven fabric 10, the size (area) of each fiber block portion 7 in a plan view of the nonwoven fabric 10 is preferably 10mm²Hereinafter, more preferably 8mm²Hereinafter, more preferably 6mm²The following. On the other hand, from the viewpoint of imparting a pattern, the size of each fiber block portion 7 in a plan view of the nonwoven fabric 10 is preferably 1mm²Above, more preferably 2.5mm²Above, more preferably 4mm²The above. Specifically, the size (area) of each fiber block portion 7 in a plan view of the nonwoven fabric 10 is preferably 1mm²Above 10mm²Hereinafter, more preferably 2.5mm²Above 8mm²Hereinafter, more preferably 4mm²Above 6mm²The following.

Further, the size of the nonwoven fabric 10 in a plan view of the fiber block portion 7 disposed as the fiber layer on the skin surface side of the absorbent article is preferably 9mm²Hereinafter, more preferably 7mm²Hereinafter, more preferably 5mm²The following.

Further, from the viewpoint of forming a pattern having a depth, the layerOf the 2 stacked layers, the size of the nonwoven fabric 10 in plan view of the fiber block portion 7 disposed as the fiber layer on the non-skin surface side of the absorbent article is preferably 2mm²Above, more preferably 3mm²Above, more preferably 5mm²The above.

From the viewpoint of maintaining a soft texture of the nonwoven fabric 10, the size (thickness) of the nonwoven fabric 10 in the thickness direction of each fiber block portion 7 is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less, in terms of the ratio to the thickness of the nonwoven fabric 10. On the other hand, from the viewpoint of texture, the size (thickness) of the nonwoven fabric 10 in the thickness direction of each fiber block portion 7 is preferably smaller in a range exceeding 0% in terms of the ratio to the thickness of the nonwoven fabric 10. Specifically, the size (thickness) of the nonwoven fabric 10 in the thickness direction of each fiber block portion 7 is preferably more than 0% and 50% or less, more preferably more than 0% and 40% or less, and further preferably more than 0% and 30% or less in terms of the ratio to the thickness of the nonwoven fabric 10.

In addition, from the viewpoint of reducing the feeling of stiffness felt when the skin contacts the fiber mass portion 7 by stacking and integrating a plurality of fiber layers, the size in the thickness direction of the nonwoven fabric 10 of the fiber mass portion 7 disposed in the fiber layer to be the skin surface side of the absorbent article among the stacked 2 layers is preferably 50% or less, more preferably 40% or less, and further preferably 30% or less in terms of the ratio to the thickness of the nonwoven fabric 10.

From the same viewpoint as described above, the size (thickness) of the nonwoven fabric 10 in the thickness direction of each fiber block portion 7 is preferably 1mm or less, more preferably 0.8mm or less, and further preferably 0.5mm or less, and is preferably smaller in a range exceeding 0 mm. Specifically, the size (thickness) of the nonwoven fabric 10 in the thickness direction of each fiber block portion 7 is preferably more than 0mm and 1mm or less, more preferably more than 0mm and 0.8mm or less, and still more preferably more than 0mm and 0.5mm or less.

(method of measuring the number, area and thickness of fiber lump portion)

A photograph was taken with a microscope (VHX-900, manufactured by Kinzhi Co., Ltd.) from the observation target surface of the nonwoven fabric cut in a 10cm square (for example, the surface 10A of the nonwoven fabric 10). The material (jpeg) of the photograph was subjected to image analysis processing using image analysis software (Nexus New quie). The binarization processing is performed to obtain the number and area of the fiber lump portions. Further, the nonwoven fabric thickness and the fiber block thickness were measured by cutting all the blocks in the thickness direction with a razor blade and observing the cross section with the microscope.

The air-through nonwoven fabric for absorbent articles of the present invention can be used as a component of an absorbent article. Examples of the absorbent articles include various articles having a function of absorbing and retaining liquid excreted by human beings, such as diapers, sanitary napkins, urine pads, and panty liners.

The air-through nonwoven fabric for an absorbent article of the present invention is incorporated in an absorbent article by combining its functions with various members used as an absorbent article. For example, in the case of having liquid permeability, it is incorporated as a topsheet, and in the case of having water repellency, it is incorporated as a side sheet. In addition, the outer cover is made thinner and more flexible, and is incorporated as an outer cover material for improving the texture of the outer side (garment side) of an absorbent article such as a diaper.

Among them, from the viewpoint that the texture of the nonwoven fabric excellent in bulkiness and soft skin touch is easily perceived by the skin and the pattern of the nonwoven fabric is easily recognized visually, the hot air nonwoven fabric for the absorbent article of the present invention is preferably arranged on the outermost layer on the skin surface side of the absorbent article, and the fiber bulk layer 8 is arranged toward the skin surface side. For example, a topsheet or a side sheet may be mentioned, and it is particularly preferable to dispose the air-through nonwoven fabric for an absorbent article of the present invention as a topsheet in an absorbent article.

Next, a preferred embodiment of the method for producing a through-air nonwoven fabric for an absorbent article of the present invention will be described. Here, a method for producing the nonwoven fabric 10 of the above embodiment will be described. However, the laminated fiber layers are not limited to 2 layers (fiber layer 1 and fiber layer 2), and 3 or more fiber layers may be laminated.

The manufacturing method of the present embodiment includes the following

steps

501 and 502.

Step 501: and a fiber opening step of forming a fiber web by performing a fiber opening process on the thermoplastic fibers a plurality of times.

Step 502: and a through-air nonwoven fabric forming step of forming a laminated web by laminating the plurality of single-layer webs obtained in the opening step, and subjecting the laminated web to through-air processing using through-air to obtain a through-air nonwoven fabric.

The manufacturing method of the present embodiment includes the following step 503.

Step 503: and a calendering step of processing one or more selected from the group consisting of the single-layer web, the laminated web, and the through-air nonwoven fabric, using a pair of calender rolls.

Step 503 is performed after step 501 and before step 502, during step 502, or after step 502.

Fig. 2 shows a manufacturing apparatus 100 that can be applied to the method for manufacturing the nonwoven fabric 10 according to the present embodiment. The manufacturing apparatus 100 includes, from the upstream side to the downstream side:

fiber opening portions

101 and 102 of a fiber material which is a raw material of the nonwoven fabric; carding

sections

103 and 104 forming a web of fibers; a laminated web forming section 105 for carrying and stacking the single-layer webs obtained by carding; a web calender 106 for applying a pressure to the laminated web; and a heat treatment unit (hot air processing unit) 107.

In the manufacturing apparatus 100, the above-described step 501 is performed in the

fiber opening sections

101 and 102 and the carding

sections

103 and 104. The step 502 is performed in the laminated web forming section 105 and the heat treatment section 107.

In the manufacturing apparatus 100, the step 503 is performed in the web calendering unit 106. The web calendering section 106 is disposed between the laminated web forming section 105 and the heat treatment section 107, and the step 503 is performed as web calendering on the laminated web in the middle of the step 502.

The opening

sections

101 and 102 have means for opening thermoplastic fibers that are the raw materials of the fiber layers 1 and 2 and feeding the thermoplastic fibers to the

subsequent carding sections

103 and 104, respectively. In the case of using the fine fibers and the coarse fibers having the above-mentioned specific fiber diameters, it is preferable to split the fine fibers and the coarse fibers separately. In fig. 2, the following is shown: the raw material fiber (fine fiber) 71 is fed to the fiber opening section 101 and opened (arrow 171), and the raw material fiber (coarse fiber) 72 is fed to the fiber opening section 102 and opened (arrow 172).

As the raw material fibers (fine fibers) 71 and the raw material fibers (coarse fibers) 72, various thermoplastic fibers that can be used for a hot air nonwoven fabric can be used. For example, a composite fiber having a core-sheath structure and having a sheath resin component with a lower melting point than the core resin component can be used.

In carding

sections

103 and 104, the fibers (arrows 173 and 174) that have been opened in opening

sections

101 and 102, respectively, are received to form single-

layer webs

81 and 82. Specifically, the assembly of fibers that have been opened in the opening

sections

101 and 102 is carded and further opened to form a sheet-like web. In the carding section 103, a single-layer web 81 based on the raw fibers (fine fibers) 71 is formed, and in the carding section 104, a single-layer web 82 based on the raw fibers (coarse fibers) 72 is formed.

In the carding

units

103 and 104, various carding machines commonly used in the production of the hot-air non-woven fabric can be used without particular limitation. Examples thereof include a parallel carding machine, a semi-random carding machine, a random carding machine, and a device in which a cross layer and a draft device are combined in a parallel carding machine. Further, the carding machine includes 3 types of rollers including a main cylinder roller covered with a zigzag wire, a work roller, and a stripper roller. The fiber assembly can be combed and opened between the main cylindrical roller and the working roller and the stripping roller. By arranging a plurality of sets of work rolls and stripping rolls for the main cylindrical roll, the fiber opening process can be performed a plurality of times in the respective carding machines of the carding

units

103 and 104.

As described above, the fiber opening process is performed a plurality of times in both the

fiber opening sections

101 and 102 and the carding

sections

103 and 104.

In the manufacturing method of the present embodiment, a fiber opening step (step 501) is performed in which the thermoplastic fibers are subjected to a plurality of fiber opening processes in the

fiber opening sections

101 and 102 and the carding

sections

103 and 104 to form a web.

Then, in the laminated web forming section 105, the single-layer web 82 formed in the carding section 104 is laminated on the single-layer web 81 formed in the carding section 103 to form the laminated web 90.

Specifically, the single-layer web 81 is carried out from the carding unit 103 along the carrying-out belt 103A and placed on the conveying belt 105A. The conveyance belt 105A conveys the single-layer fiber web 81 downstream. The single-layer web 82 is carried out along the carrying-out belt 104A from carding, is guided to the conveying belt 105A, and is stacked on the single-layer web 81 being conveyed. The formed laminated web 90 is thereby conveyed downstream along the conveying belt 105A. In the laminated web 90, the portions corresponding to the single-

layer webs

81 and 82 are simply referred to as

webs

81 and 82.

In the laminated web 90, the web 82 is formed of raw material fibers (coarse fibers) 72, and the web 81 is formed of raw material fibers (fine fibers) 71. Thus, the average fiber diameter of web 82 is larger than the average fiber diameter of web 81. In addition, in this way, the fiber web 81 becomes a fiber bulk layer 8 including the fine fibers having the specific fiber diameter in the completed nonwoven fabric 10. The fiber web 82 can be a non-fiber bulk layer 9 containing coarse fibers having the specific fiber diameter in the completed nonwoven fabric 10. In the completed nonwoven fabric 10, the basis weight of the non-fiber bulk layer 9 can be made larger than that of the fiber bulk layer 8 by making the mass of the fibers supplied from the fiber opening section 102 to the carding section 104 larger than that supplied from the fiber opening section 101 to the carding section 103.

As described above, in the production method of the present embodiment, it is preferable to form a laminated fiber web using a plurality of types of fibers having different fiber diameters. In particular, it is more preferable to make the fiber diameter of the fiber web 82 different from that of the fiber web 81.

As the fibers having different fiber diameters, it is preferable to use fine fibers having a fiber diameter of 1dtex or more and 2.2dtex or less. Further, the fiber diameter of the fine fiber is more preferably within the above-mentioned range of fiber diameter.

In the web calendering section 106, web calendering (hereinafter, sometimes simply referred to as "calendering") is performed in which the conveyed laminated web 90 is sandwiched between a pair of calendering rolls 106A and 106B and pressed. This makes it possible to smooth the surface of the web having the fiber block portions 7, thereby reducing the stiffness of the fiber block portions 7.

In particular, in the manufacturing method of the present embodiment, since the laminated fiber web 90 before being nonwoven-woven is subjected to calendering, fibers are not fixed by fusion to each other, and the fibers can be moved largely. That is, in the calendering process of the present embodiment, fibers at the welded portion between the fibers may not be peeled off or broken, and the fibers concentrated in the fiber block portion 7 can be appropriately dispersed (the interval between the fibers is enlarged) while maintaining the fiber state well, so that the fiber block portion 7 can be distributed well. This improves the effect of reducing the stiffness of the fiber block portion 7. In addition, with respect to the pressing in the thickness direction by the calendering, in both of the

webs

81 and 82 before the formation of the laminated nonwoven fabric, the fibers of the fiber block portion 7 are easily dispersed from each other, and the effect of reducing the hard feeling of the fiber block portion 7 is enhanced in the whole laminated web 90 (hereinafter, the laminated web obtained by the web calendering may be referred to as a laminated web 95). In addition, in a series of manufacturing steps, the following hot air treatment is performed after the above-described calendering, and thus the hot air treatment can be utilized as a recovery treatment of the thickness of the nonwoven fabric. That is, in the present embodiment, the processing steps performed in this order are advantageous in recovering the thickness of the laminated fiber web 95 to make it more bulky, to provide a soft texture and to form a pattern.

In the heat treatment section 107, the laminated fiber web 95 obtained by the fiber web calendering is subjected to hot air processing using hot air.

Specifically, the heat treatment unit 107 includes a filter 107A and a conveyor belt 107B having an air-permeable mesh wound around the filter 107A. Hot air is blown into the filter cover 107A from above to the conveyor belt 107B (arrow F shown in fig. 2). The hot air blown by the air-permeable net is blown off by the conveyor belt 107B. The laminated web 95 obtained by the web calendering process is extruded to the heat treatment unit 107 by the rotation of the rolls of the web calendering unit 106. In the heat treatment section 107, the laminated fiber web 95 is conveyed into the filter housing 107A by the conveyor belt 107B. Hot air heated to a specific temperature is blown through the laminated web 95 in the inside of the filter housing 107A from above the laminated web 95 (i.e., above the web 82) in the thickness direction. That is, the laminated fiber web 95 is subjected to hot air processing. In the laminated fiber web 95, the interval between the fibers in the fiber block portion 7 is thereby expanded by the above-described fiber web calendering, and the intersections between the fibers are fused by blowing hot air under the condition that the fiber block portion 7 is in a fiber state with a soft feeling of hardness. Thereby, the air-through nonwoven fabric for absorbent articles 10 of the present embodiment can be obtained.

As described above, in the manufacturing method of the present embodiment, the single-

layer webs

81 and 82 obtained through the opening step of the step 501 are subjected to the step 502 and the step 503 by laminating the web forming section 105, the web calendering section 106, and the heat treatment section 107. Specifically, the step 502 is performed by the laminated web forming section 105 and the heat treatment section 107, and the calendering process is performed by the web calendering section 106 in the middle (step 503).

By performing these

steps

501, 502, and 503, the air-through nonwoven fabric for absorbent articles 10 of the present embodiment can be manufactured with high accuracy. That is, the hot air nonwoven fabric 10 for an absorbent article having a pattern excellent in bulkiness and soft texture can be manufactured with high accuracy even though it includes the fiber layer 8 having the fiber block portions 7. The produced air-through nonwoven fabric for absorbent articles 10 is wound into a roll shape as necessary.

In the manufacturing method of the present embodiment, the calendering step (step 503) is performed on the laminated fiber web 90 before the hot air processing. However, the present invention is not limited to this, and the single-layer web 81 and the single-layer web 82 before lamination may be separately calendered, or the hot-air nonwoven fabric after hot-air processing may be calendered. When the through-air nonwoven fabric is subjected to the calendering process, the through-air nonwoven fabric to be processed is a raw material through-air nonwoven fabric before the through-air nonwoven fabric 10 for an absorbent article of the present embodiment.

In the manufacturing method of the present embodiment, by performing the calendering step (step 503), the fiber block portion 7 is spread by calendering, and the portion other than the fiber block portion 7 is smoothed by calendering to be smooth. The nonwoven fabric 10 having a smooth surface is obtained by integrating a plurality of fiber layers while maintaining the thickness thereof, and therefore has a thickness and cushioning properties to the extent of reducing the feeling of foreign matter (discomfort) on the skin of the fiber block portion 7.

In the manufacturing method of the present embodiment, the fiber lumps can be dispersed in a series of manufacturing steps of the nonwoven fabric. Therefore, it is not necessary to introduce a fiber block inspection device after the production of the nonwoven fabric, and the production cost can be reduced. Further, since it is not necessary to perform an inspection process after the production, a post-calendering process, and a hot air recovery process, the production efficiency of the nonwoven fabric can be improved.

The calendering is preferably a web calendering performed on one or more selected from a single-layer web and a laminated web, from the viewpoint of effectively reducing the stiffness of the fiber block portion 7.

The calendering is not limited to being performed in only 1 stage among the single-layer web stage, the web lamination stage, and the hot-air nonwoven fabric stage, and may be performed in 2 or more stages. Further, the calendering process is not limited to being performed only 1 time at each stage, and may be performed 2 or more times. For example, the laminated web 90 of the present embodiment is not limited to the case of performing calendering only 1 time, and may be performed 2 times or more.

The linear pressure in the calendering process, that is, the linear pressure applied to the laminated web 90, the single-

layer webs

81 and 82, and the through-air nonwoven fabric (raw material through-air nonwoven fabric) nipped by the calender rolls 106A and 106B is preferably the highest of the linear pressures applied to the single-

layer webs

81 and 82, the

laminated webs

90 and 95, and the through-air nonwoven fabric 601 by all the rolls in all the processes. All the rolls herein mean all the rolls used in all the manufacturing processes except the above-described calender rolls 106A and 106B. For example, a nip roll for conveying the nonwoven fabric after the heat treatment, a nip roll or a press roll at the time of winding, a press roll at the time of slitting thereafter, and the like are suitable for this purpose.

In particular, the linear pressure (P) applied to the single-

layer fiber webs

81 and 82 and the laminated fiber web 90 in the calendering process is preferably 20N/cm or more, more preferably 100N/cm or more, and still more preferably 180N/cm or more, from the viewpoint of effectively reducing the stiffness of the fiber block portion 7 before heat fusion. Further, the linear pressure (P) is preferably 700N/cm or less, more preferably 500N/cm or less, and still more preferably 250N/cm or less, from the viewpoint of the recovery from the thickness after pressing. Specifically, the linear pressure (P) is preferably 20N/cm to 700N/cm, more preferably 100N/cm to 500N/cm, and still more preferably 180N/cm to 250N/cm.

The pair of calender rolls 106A and 106B used in the web calender 106 are rolls having smooth peripheral surfaces. The raw material may be any of various materials used in calendering. The material of calender roll 106A may be the same as or different from the material of calender roll 106B.

Among them, from the viewpoint of further improving the effect of reducing the hard feeling of the fiber mass portion 7, the calender roll used in the calendering process is preferably a combination of a resin roll and a steel roll. In the web calendering process according to the present embodiment, the calender roll 106A is a steel roll as a contact with the web 82 including coarse fibers of the laminated web 90, and the calender roll 106B is a resin roll as a contact with the web 81 including fine fibers of the laminated web 90. However, the arrangement of the resin roll and the steel roll is not limited to this, and the arrangement may be combined in reverse.

From the viewpoint of further improving the effect of reducing the hard feeling of the fiber mass portion 7, the hardness of the resin roller is preferably 20 degrees or more, more preferably 50 degrees or more, and further preferably 80 degrees or more in terms of D hardness (JIS K6253-3). From the same viewpoint as described above, the hardness of the resin roller is preferably 100 degrees or less, more preferably 95 degrees or less, and still more preferably 90 degrees or less in terms of D hardness (JIS K6253-3). Specifically, the hardness of the resin roll is preferably 20 degrees to 100 degrees, more preferably 50 degrees to 95 degrees, and still more preferably 80 degrees to 90 degrees.

Further, the hot air processing preferably includes a plurality of hot air treatments.

Fig. 3 shows an embodiment of a heat treatment unit (hot air processing unit) including the first hot air treatment unit 117 and the second hot air treatment unit 127. In this embodiment, the hot air processing is performed in 2 times of the first hot air treatment and the second hot air treatment. However, the number of hot air treatments is not limited to 2 in FIG. 3, and may be 3 or more. When the hot air processing includes 3 or more hot air treatments, the "hot air treatment at the subsequent stage" with respect to the "first hot air treatment" indicates the second and subsequent hot air treatments. In the 2 hot air treatments of fig. 3, the "first hot air treatment" means the first hot air treatment, and the "subsequent hot air treatment" means the second hot air treatment. In the hot air step (2 hot air treatments) shown in fig. 3, hot air is blown to the filter cover 107C of the first hot air treatment unit 117 (arrow F1), and hot air is blown to the filter cover 107D of the second hot air treatment unit 127 (arrow F2). At this time, the laminated web 95 subjected to the web calendering process is continuously conveyed from the first hot air processing section 117 to the second hot air processing section 127 by the conveying belt 107B. Thereby, the first hot air treatment and the second hot air treatment are continuously performed on the laminated web 95.

In the hot air step, the air velocity of the hot air in the subsequent hot air treatment is preferably higher than that in the first hot air treatment, that is, the first hot air treatment is performed at a low air velocity. This suppresses the web from becoming fluffy due to the pressure of the air in the hot air treatment unit, and exhibits a hot air recovery effect to thereby make the web fluffy. In particular, when the laminated web 90 or the single-

layer webs

81 and 82 before nonwoven formation is calendered as in the present embodiment, the above-described treatment in the subsequent hot air treatment is effective.

Specifically, the wind speed S1 of the hot wind in the first hot wind treatment is preferably 0.2m/sec or more, more preferably 0.25m/sec or more, and still more preferably 0.4m/sec or more. The wind speed S1 of the hot wind in the first hot wind treatment is preferably 1.2m/sec or less, more preferably 0.8m/sec or less, and still more preferably 0.5m/sec or less. Specifically, the wind speed S1 is preferably 0.2m/sec to 1.2m/sec, more preferably 0.25m/sec to 0.8m/sec, and still more preferably 0.4m/sec to 0.5 m/sec. This suppresses the web from being flattened and exhibits a thickness recovery effect.

The wind speed S2 of the hot wind in the hot wind treatment in the subsequent stage is preferably 0.8m/sec or more, more preferably 0.9m/sec or more, and further preferably 1.2m/sec or more. The wind speed S2 of the hot wind in the hot wind treatment in the subsequent stage is preferably 1.6m/sec or less, more preferably 1.4m/sec or less, and still more preferably 1.3m/sec or less. Specifically, the wind speed S2 is preferably 0.8m/sec to 1.6m/sec, more preferably 0.9m/sec to 1.4m/sec, and still more preferably 1.2m/sec to 1.3 m/sec. This allows air to uniformly penetrate the web, and effectively applies heat energy to the web, thereby forming a nonwoven fabric structure.

The difference S3 (S2-S1) between the wind speed S1 of the hot wind in the first hot wind treatment and the wind speed S2 of the hot wind in the subsequent hot wind treatment is preferably more than 0m/sec, more preferably 0.4m/sec or more, and still more preferably 0.8m/sec or more. The difference S3 (S2-S1) between the wind speed S1 of the hot wind in the first hot wind treatment and the wind speed S2 of the hot wind in the subsequent hot wind treatment is preferably 1.4m/sec or less, more preferably 1.2m/sec or less, and still more preferably 1m/sec or less. Specifically, the difference S3 (S2-S1) between the wind speed S1 of the hot wind in the first hot wind treatment and the wind speed S2 of the hot wind in the subsequent hot wind treatment is preferably more than 0m/sec and 1.4m/sec or less, more preferably 0.4m/sec or more and 1.2m/sec or less, and still more preferably 0.8m/sec or more and 1m/sec or less. Therefore, the fluffy recovery and the non-woven fabric can be effectively realized.

In the hot air step, the temperature of the hot air in the subsequent hot air treatment is preferably higher than that in the first hot air treatment. This advances the welding of the fibers in stages, and effectively exhibits recovery of the fiber web in the hot air treatment section. In particular, when the laminated web 90 or the single-

layer webs

81 and 82 before nonwoven formation is calendered as in the present embodiment, the above-described effects are further enhanced in the subsequent hot air treatment.

Specifically, the temperature P1 of the hot air in the first hot air treatment is preferably 85 ℃ or higher, more preferably 90 ℃ or higher, and still more preferably 100 ℃ or higher. The temperature P1 of the hot air in the first hot air treatment is preferably 134 ℃ or lower, more preferably 115 ℃ or lower, and still more preferably 105 ℃ or lower. Specifically, the temperature P1 of the hot air in the first hot air treatment is preferably 85 ℃ to 134 ℃, more preferably 90 ℃ to 115 ℃, and still more preferably 100 ℃ to 105 ℃. This can effectively exhibit the recovery properties of the fiber web in the hot air treatment section.

The temperature P2 of the hot air in the hot air treatment in the subsequent stage is equal to or higher than the melting point of the component on the surface of the fiber to be used (for example, the sheath portion of the core-sheath composite fiber), and is preferably 145 ℃ or lower, more preferably 137 ℃ or lower, and still more preferably 134 ℃ or lower. Specifically, the temperature P2 of the hot air in the hot air treatment in the subsequent stage is preferably not less than the melting point of the component on the surface of the fiber to be used and not more than 145 ℃, more preferably not less than the melting point of the component on the surface of the fiber to be used and not more than 137 ℃, and still more preferably not less than the melting point of the component on the surface of the fiber to be used and not more than 134 ℃. This enables production of a nonwoven fabric having good texture and good texture.

The difference P3 (P2-P1) between the temperature P1 of the hot air in the first hot air treatment and the temperature P2 of the hot air in the subsequent hot air treatment is preferably more than 0 ℃, more preferably 20 ℃ or more, and still more preferably 30 ℃ or more. The difference P3 (between P2 and P1) between the temperature P1 of the hot air in the first hot air treatment and the temperature P2 of the hot air in the subsequent hot air treatment is preferably 60 ℃ or less, more preferably 40 ℃ or less, and still more preferably 35 ℃ or less. Specifically, the difference P3 (P2-P1) between the temperature P1 of the hot air in the first hot air treatment and the temperature P2 of the hot air in the subsequent hot air treatment is preferably more than 0 ℃ and 60 ℃ or less, more preferably 20 ℃ to 40 ℃ or less, and still more preferably 30 ℃ to 35 ℃. This enables the production of a nonwoven fabric having a bulky texture.

Further, in the method for producing a hot-air nonwoven fabric for an absorbent article according to the present embodiment, as described below, it is preferable that unnecessary portions such as leftover materials generated in the production process are temporarily collected and returned to the opening process again (step 504).

In step 504, one or both of the following steps are included: a step of recovering the end of the web in the width direction in a carding machine used in the opening step; and a step of partially recovering the air-through nonwoven fabric, and cutting and opening a part of the recovered air-through nonwoven fabric. The collected fiber web and the cut and opened part of the hot-air non-woven fabric are supplied to the opening step. The portions of the cut and opened air-through nonwoven fabric include, but are not limited to, edge portions at the ends in the width direction, and refer to processing condition-adjusted products, defective products, and the like generated in the nonwoven fabric production process.

Fig. 2 shows a specific example of the step 504. The single-

layer webs

81 and 82 formed in the carding units of the carding

units

103 and 104 are sucked and collected (arrows 181 and 182) at their widthwise ends (not shown). The hot-air nonwoven fabric 10 obtained by hot-air processing in the heat treatment section 107 is partially collected (arrow 183). In this case, since the collected part of the through-air nonwoven fabric cannot be directly reused, the nonwoven fabric is cut and opened in the cutting/opening section 108 to return the nonwoven fabric to a fibrous form.

The collected fiber web and the cut and opened part of the air-through nonwoven fabric are returned to the fiber opening section 101, and are opened again to be used as a material for forming a fiber web (arrow 184). At this time, the fiber can be returned to either the fiber opening section 101 or the fiber opening section 102. Fig. 2 shows a state where the fiber is returned to the fiber opening section 101. When returning to the opening section 101, it is preferable to appropriately adjust the amount of the new raw material fibers (fine fibers) 71 to be fed so that the content of the coarse fibers is kept within several% (for example, within 5%) while the ratio of the fine fibers in the formed fiber web 81 is kept at a constant value or more. This makes it possible to form the fiber block portion 7 on the web 81 while containing a large number of fine fibers, thereby achieving a soft texture on the face 10A side of the nonwoven fabric 10.

The material is not limited to the form shown in fig. 2. For example, the following method is also possible: the material recovered from the carding unit 103 is returned to the opening unit 101, and the material recovered from the carding unit 104 is returned to the opening unit 102. At this time, it is preferable that the portion of the air-through nonwoven fabric cut and opened is returned to the opening section 102.

As described above, according to the production method of the present embodiment, the nonwoven fabric 10 having a pattern excellent in bulkiness and soft texture can be suitably produced. In particular, the nonwoven fabric 10 having the physical properties indicated by the thicknesses T1, T2 and the difference T3 thereof (T1-T2) under the pressure of 7.64kPa, and the average friction coefficients Q1, Q2 and the difference Q3 (Q1-Q2) can be suitably produced. The pattern formed by the fiber block portions 7, particularly the pattern formed by the fiber block portions 7 having a flat thickness, provides the nonwoven fabric 10 with aesthetic qualities.

The obtained hot-air nonwoven fabric for an absorbent article of the present invention is incorporated as a specific component of the absorbent article in the manufacturing process of the absorbent article according to the purpose (incorporation process). The incorporation step is preferably, for example, the following step. That is, the obtained hot-air nonwoven fabric for an absorbent article of the present invention is cut into a size, a shape, or the like that conforms to a target, and is placed at a specific position with respect to other constituent members. Then, if necessary, the absorbent article is assembled by being rotated and folded together with other members and joined. In this way, the process of incorporating the hot-air nonwoven fabric for an absorbent article of the present invention in the process of manufacturing an absorbent article is passed through, and the intended absorbent article is manufactured.

Among them, in the hot air nonwoven fabric for an absorbent article of the present invention, in terms of achieving both bulkiness and a soft skin touch and providing a pattern that can visually attract a user, the incorporation step is preferably a step of incorporating the hot air nonwoven fabric into an outermost member (for example, a topsheet or a side sheet) on the skin surface side of the absorbent article. Particularly, the step of incorporating the sheet into an absorbent article as a top sheet that is most conspicuous when in contact with the skin is preferable. In this case, the air-through nonwoven fabric for an absorbent article of the present invention preferably has a configuration in which the fiber layer having the fiber block portion is the outermost layer of the nonwoven fabric. More preferably, the hot air nonwoven fabric for an absorbent article of the present invention is disposed on the outermost layer on the skin surface side of the absorbent article, and the fiber layer having the fiber block portion is disposed toward the skin surface side of the absorbent article.

In the above embodiment, the present invention further discloses the following air-through nonwoven fabric for an absorbent article and a method for producing the air-through nonwoven fabric for an absorbent article.

＜1＞

A through-air nonwoven fabric for an absorbent article, which is a through-air nonwoven fabric in which 2 or more fiber layers are laminated, has at least 1 fiber layer containing thermoplastic fibers and having a fiber block portion.

＜2＞

The air-through nonwoven fabric for absorbent articles according to the above < 1 >, wherein the air-through nonwoven fabric for absorbent articles has fine fibers and coarse fibers having a fiber diameter larger than that of the fine fibers, and the fine fibers have a fiber diameter of 1dtex or more and 2.2dtex or less, preferably 1dtex or more, more preferably 1.2dtex or more, preferably 2dtex or less, more preferably 1.5dtex or less,

the fiber layer having the fiber block portion contains the fine fibers.

＜3＞

The air-through nonwoven fabric for absorbent articles according to the above < 2 >, wherein the content of the fine fibers in the fiber layer having the fiber mass portion is 50% by mass or more, preferably 80% by mass or more, and more preferably 100% by mass.

＜4＞

The air-through nonwoven fabric for an absorbent article according to any one of the above items < 1 > to < 3 >, which has at least 1 fiber layer having no fiber block portion.

＜5＞

The air-through nonwoven fabric for absorbent articles according to the above < 4 >, wherein the air-through nonwoven fabric for absorbent articles has coarse fibers and fine fibers having a fiber diameter smaller than the coarse fibers, the coarse fibers have a fiber diameter of more than 2.2dtex and 7dtex or less, preferably more than 2.2dtex, more preferably 4.4dtex or more, preferably 5.5dtex or less, more preferably 5dtex or less,

the fiber layer not having the fiber block portion includes the coarse fibers.

＜6＞

The air-through nonwoven fabric for absorbent articles according to the above < 5 >, wherein the content of the coarse fibers in the fiber layer not having the fiber mass portion is 50% by mass or more, preferably 80% by mass or more, and more preferably 100% by mass.

＜7＞

The air-through nonwoven fabric for absorbent articles according to the above < 5 > or < 6 >, wherein the content of the coarse fibers in the layer having the fiber block portion is 50% by mass or less, preferably 30% by mass or less, and more preferably 10% by mass or less.

＜8＞

The air-through nonwoven fabric for an absorbent article according to any one of the above items < 4 > to < 7 >, wherein the average fiber diameter of the fiber layer not having the fiber block portion is larger than the average fiber diameter of the fiber layer having the fiber block portion.

＜9＞

The air-through nonwoven fabric for absorbent articles according to < 8 > above, wherein the difference between the average fiber diameter of the fiber layer not having the fiber block portion and the average fiber diameter of the fiber layer having the fiber block portion is more than 0dtex and 5.6dtex or less, preferably 2.2dtex or more, more preferably 3dtex or more, preferably 4dtex or less, more preferably 3.5dtex or less.

＜10＞

The air-through nonwoven fabric for an absorbent article according to any one of the above items < 4 > to < 9 >, wherein the basis weight of the fiber layer not having the fiber block portion is larger than that of the fiber layer having the fiber block portion.

＜11＞

The nonwoven fabric for absorbent articles according to the above < 10 >, wherein the difference between the basis weight of the fiber layer not having the fiber block portion and the basis weight of the fiber layer having the fiber block portion is more than 0g/m²And 20g/m²Hereinafter, it is preferably 3g/m²Above, more preferably 5g/m²Above, preferably 15g/m²In the following, the following description is given,more preferably 10g/m²The following.

＜12＞

The air-through nonwoven fabric for absorbent articles according to any one of the above items < 1 > to < 11 >, wherein the basis weight of the entire air-through nonwoven fabric for absorbent articles is 15g/m²Above 40g/m²Hereinafter, it is preferably 18g/m²Above, more preferably 20/m²Above, preferably 30g/m²Hereinafter, more preferably 25g/m²The following.

＜13＞

The air-through nonwoven fabric for absorbent articles according to any one of the above items < 1 > < 12 >, wherein when a thickness of the air-through nonwoven fabric for absorbent articles measured under a pressure of 7.64kPa at a position where the fiber mass portion is arranged is T1, and a thickness of the air-through nonwoven fabric for absorbent articles measured under the same pressure at a position where the fiber mass portion is not arranged is T2, a difference T3 in thickness defined by T3 ═ T1-T2 is 0.4mm or less, preferably 0.3mm or less, more preferably 0.2mm or less, and still more preferably 0 (zero) mm.

＜14＞

The air-through nonwoven fabric for an absorbent article according to any one of the above items < 1 > to < 13 >, wherein an average friction coefficient of a position where the fiber block portion is arranged in the air-through nonwoven fabric for an absorbent article is 1.6 or more and 2.5 or less, preferably 1.6 or more, preferably 2.4 or less, and more preferably 2.3 or less.

＜15＞

The air-through nonwoven fabric for absorbent articles according to the above < 14 >, wherein a difference between an average friction coefficient at a position where the fiber block portion is arranged and an average friction coefficient at a position where the fiber block portion is not arranged in the air-through nonwoven fabric for absorbent articles is 0.7 or less, preferably 0.5 or less, more preferably 0.32 or less, still more preferably 0.3 or less, and particularly preferably 0 (zero).

＜16＞

The air-through nonwoven fabric for an absorbent article according to any one of the above items < 1 > to < 15 >, wherein the fiber block portion has a flat shape flattened in the thickness direction of the nonwoven fabric in a cross section in the thickness direction of the nonwoven fabric, and has a structure in which the surface of the fiber block portion on the surface side of the nonwoven fabric is smooth.

＜17＞

The air-through nonwoven fabric for absorbent articles according to any one of the above items < 1 > to < 16 >, wherein the fiber layer having the fiber block portion is an outermost layer of the air-through nonwoven fabric for absorbent articles.

＜18＞

An absorbent article having the air-through nonwoven fabric for an absorbent article described in any one of the above-mentioned < 1 > -to < 17 >.

＜19＞

An absorbent article, wherein the absorbent article hot-air nonwoven fabric according to < 17 > is disposed on the outermost layer on the skin surface side of the absorbent article, and the fiber layer having the fiber block portion is disposed facing the skin surface side.

＜20＞

The absorbent article according to the above < 18 > or < 19 > having the above-mentioned air-through nonwoven fabric for an absorbent article as a topsheet.

＜21＞

A method for producing a hot-air nonwoven fabric for an absorbent article, comprising:

a fiber opening step of forming a fiber web by performing a fiber opening process on thermoplastic fibers a plurality of times;

a through-air nonwoven fabric forming step of forming a laminated web by laminating a plurality of single-layer webs obtained in the opening step, and subjecting the laminated web to through-air processing using through-air to obtain a through-air nonwoven fabric; and

and a calendering step of processing one or more selected from the group consisting of the single-layer web, the laminated web, and the through-air nonwoven fabric using a pair of calender rolls.

＜22＞

The method of producing a through-air-laid nonwoven fabric for absorbent articles as described in the above < 21 >, wherein in all steps of the method of producing a through-air-laid nonwoven fabric for absorbent articles,

the calendering process is performed by calendering the single-layer web, the laminated web, and the through-air nonwoven fabric.

＜23＞

The method for producing a hot-air-through nonwoven fabric for an absorbent article according to the above < 21 > or < 22 >, wherein the calendering step is a web calendering step performed on one or more selected from the group consisting of the single-layer web and the laminated web.

＜24＞

The method of producing a through-air nonwoven fabric for absorbent articles as described in < 23 >, wherein the linear pressure applied to the single-layer web or the laminated web in the web calendering process is 20N/cm or more and 700N/cm or less, preferably 100N/cm or more, more preferably 180N/cm or more, preferably 500N/cm or less, and more preferably 250N/cm or less.

＜25＞

The method of producing a hot-air nonwoven fabric for an absorbent article according to any one of the above items < 21 > to < 24 >, wherein the pair of calender rolls used in the calendering process is a combination of a resin roll and a steel roll.

＜26＞

The method of producing a hot-air nonwoven fabric for absorbent articles as described in < 25 >, wherein the resin roll has a hardness of 20 to 100, preferably 50 degrees, more preferably 80 degrees, preferably 95 degrees, and more preferably 90 degrees, in terms of D durometer.

＜27＞

The method of producing a through-air nonwoven fabric for absorbent articles as described in any one of the above items < 21 > to < 26 >, wherein the through-air treatment includes a plurality of through-air treatments, and the air velocity of the through-air in the subsequent through-air treatment is higher than that in the first through-air treatment.

＜28＞

The method of producing a hot-air nonwoven fabric for an absorbent article according to item < 27 >, wherein the air velocity of the hot air in the first hot-air treatment is 0.2m/sec or more and 1.2m/sec or less, preferably 0.25m/sec or more, more preferably 0.4m/sec or more, preferably 0.8m/sec or less, more preferably 0.5m/sec or less.

＜29＞

The method of producing a hot-air nonwoven fabric for an absorbent article according to the above < 27 > or < 28 >, wherein the air velocity of the hot air in the hot air treatment in the subsequent stage is 0.8m/sec or more and 1.6m/sec or less, preferably 0.9m/sec or more, more preferably 1.2m/sec or more, preferably 1.4m/sec or less, more preferably 1.3m/sec or less.

＜30＞

The method of producing a hot-air nonwoven fabric for an absorbent article according to any one of the above items < 27 > < 29 >, wherein a difference between a wind speed of the hot air in the first hot-air treatment and a wind speed of the hot air in the subsequent hot-air treatment exceeds 0m/sec and is not more than 1.4m/sec, preferably not less than 0.4m/sec, more preferably not less than 0.8m/sec, preferably not more than 1.2m/sec, more preferably not more than 1 m/sec.

＜31＞

The method of producing a hot-air nonwoven fabric for an absorbent article according to any one of the above items < 21 > to < 30 >, wherein the hot-air treatment includes a plurality of hot-air treatments, and the temperature of the hot air in the subsequent hot-air treatment is higher than that in the first hot-air treatment.

＜32＞

The method of producing a hot-air nonwoven fabric for absorbent articles as described in < 31 >, wherein the temperature of the hot air in the first hot-air treatment is 85 ℃ to 134 ℃, preferably 90 ℃ to 100 ℃, preferably 115 ℃ to 105 ℃.

＜33＞

The method for producing a hot-air nonwoven fabric for an absorbent article according to the above < 31 > or < 32 >, wherein the temperature of the hot air in the hot air treatment in the subsequent stage is not less than the melting point of the component on the surface of the fiber to be used but not more than 145 ℃, preferably not less than the melting point of the component on the surface of the fiber to be used, preferably not more than 137 ℃, and more preferably not more than 134 ℃.

＜34＞

The method of producing a hot-air nonwoven fabric for an absorbent article according to any one of the above items < 31 > to < 33 >, wherein a difference between the temperature of hot air in the first hot-air treatment and the temperature of hot air in the subsequent hot-air treatment is more than 0 ℃ and 60 ℃ or less, preferably 20 ℃ or more, more preferably 30 ℃ or more, preferably 40 ℃ or less, and more preferably 35 ℃ or less.

＜35＞

The method for producing a hot-air nonwoven fabric for an absorbent article according to any one of the above items < 21 > to < 34 >, comprising one or both of the following steps: a step of recovering the end of the web in the width direction in a carding machine used in the opening step; and a step of partially recovering the through-air nonwoven fabric, and cutting and opening a part of the recovered through-air nonwoven fabric; and is

The collected fiber web and the cut and opened portion of the air-through nonwoven fabric are supplied to the opening step.

＜36＞

The method of manufacturing a through-air nonwoven fabric for an absorbent article according to any one of the above items < 21 > to < 35 >, wherein the laminated web has a plurality of types of fibers having different fiber diameters.

＜37＞

The method for producing a hot-air nonwoven fabric for an absorbent article according to any one of the above items < 21 > to < 36 >, wherein the laminated fiber web has fine fibers having a fiber diameter of 1dtex or more and 2.2dtex or less, preferably 1dtex or more, more preferably 1.2dtex or more, preferably 2dtex or less, more preferably 1.5dtex or less.

＜38＞

A method for manufacturing an absorbent article, comprising the steps of: the absorbent article manufactured by the manufacturing method according to any one of the above-mentioned < 21 > -37 > is incorporated into an absorbent article using a hot-air nonwoven fabric.

＜39＞

The method of manufacturing an absorbent article according to the above < 38 >, comprising the steps of: the absorbent article was incorporated into an absorbent article using the air-through nonwoven fabric as a topsheet.

Examples

The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited thereto. In the following table, "←" indicates the same contents as those described on the left.

(example 1)

The nonwoven fabric sample of example 1 was produced at a processing speed of 10m/min by using the production apparatus shown in FIG. 2, as follows.

First, a core-sheath thermoplastic fiber (core is polyethylene terephthalate resin and sheath is polyethylene resin) having a fiber diameter of 1.4dtex was used as the raw material fiber (fine fiber) 71 for forming the fiber layer 1. Using this raw material fiber 71, a plurality of opening treatments were performed in the opening section 101 and the carding section 103 to produce a base weight of 10g/m²The single-layer web 81.

Further, a core-sheath type (core is polyethylene terephthalate resin and sheath is polyethylene resin) thermoplastic fiber having a fiber diameter of 4.4dtex is used as the raw material fiber (coarse fiber) 72 forming the fiber layer 2. Using the raw material fiber 72, a plurality of opening treatments were performed in the opening part 102 and the carding part 104 to prepare a fiber having a basis weight of 15g/m²A single layer of web 82.

Then, in the laminated web forming section 105, the single-layer web 82 is laminated on the single-layer web 81 to form the laminated web 90. In the web calendering section 106, the laminated web 90 is subjected to web calendering. In the web calendering section 106, a calendering roll 106A of a steel body on the upper layer side and a resin roll 106B (D hardness: 90 degrees) on the lower layer side were used to set the linear pressure to 200N/cm.

In the heat treatment section 107, the laminated web 95 obtained by the web calendering is subjected to hot air processing in which 2 hot air treatments shown in fig. 3 are performed. The wind speeds and temperatures of the first and second hot air treatments are shown in table 1. Thus, the nonwoven fabric sample of example 1 was produced.

In the above-described manufacturing method, the widthwise end portion of the formed web and a part of the nonwoven fabric are not collected and returned to the opening step. Therefore, the fiber diameter of the raw material fiber (fine fiber) 71 is the average fiber diameter of the fiber layer 1, and the fiber diameter of the raw material fiber (coarse fiber) 72 is the average fiber diameter of the fiber layer 2.

(examples 2 to 7)

Nonwoven fabric samples of examples 2 to 7 were produced in the same manner as in example 1, except that the temperature and the air speed of the first hot air treatment were set to values shown in table 1.

(example 8)

A nonwoven fabric sample of example 8 was produced in the same manner as in example 1, except that the web calendering was not performed, and the nonwoven fabric after the hot air treatment was subjected to the nonwoven fabric calendering shown in table 1.

(example 9)

A nonwoven fabric sample of example 9 was produced in the same manner as in example 1, except that the fiber diameter of the raw material fibers (fine fibers) forming the fiber layer 1 was changed to 2.0dtex, and the temperature and air speed of the first hot air treatment were changed to values shown in table 1.

(example 10)

The nonwoven fabric sample of example 10 was produced in the same manner as in example 9, except that the fiber diameter of the raw material fiber 72 forming the fiber layer 2 was changed to 2.0 dtex.

(example 11)

A nonwoven fabric sample of example 11 was produced in the same manner as in example 10, except that the fiber diameter of the raw material fibers (fine fibers) forming the fiber layer 1 and the fiber diameter of the raw material fibers 71 forming the fiber layer 2 (lower layer) were set to 1.4 dtex.

(example 12)

A nonwoven fabric sample of example 12 was produced in the same manner as in example 11, except that the temperature and the air speed of the first hot air treatment were set to the values shown in table 2.

(example 13)

A nonwoven fabric sample of example 13 was produced in the same manner as in example 12, except that the web calendering was not performed, and the nonwoven fabric after the hot air treatment was subjected to the nonwoven fabric calendering shown in table 2.

Comparative example 1

A nonwoven fabric sample of comparative example 1 was produced in the same manner as in example 1, except that the calendering process was not performed.

Comparative example 2

A nonwoven fabric sample of comparative example 2 was produced in the same manner as in comparative example 1, except that the fiber diameter of the raw material fiber 71 forming the fiber layer 2 (lower layer) was set to 1.4 dtex.

(test)

[1] Bulkiness of the fiber

(1) Thickness of nonwoven fabric sample under 0.05kPa load

The measurement was carried out using a laser type thickness meter manufactured by Ohlong as a laser sensor (model ZS-LD80) and a controller (model ZS-LDC 11).

In the measurement of the thickness, the thickness in the pressurized state was measured by disposing a vertical (0.05kPa) between the tip of the laser sensor and the nonwoven fabric sample to be measured. The measurement was performed for 5 points or more, and the average value of the measurements was calculated. The 0.05kPa is a load obtained by assuming an apparent thickness of the nonwoven fabric so as not to collapse the thickness as much as possible.

(2) Thickness of nonwoven fabric sample at 7.64kPa

The thickness of the nonwoven fabric sample at the position where the fiber block was arranged (T1) and the thickness of the nonwoven fabric sample at the position where the fiber block was not arranged (T2) were measured by the methods described above (method for measuring the thickness of a nonwoven fabric under a pressure of 7.64 kPa). Further, the difference in thickness was calculated (T3 — T1-T2).

[2] Friction of

The MIU value (Q1) at the position where the fiber block portion was arranged and the MIU value (Q2) at the position where the fiber block portion was not arranged were measured for each nonwoven fabric sample based on the method described above (method for measuring average friction coefficient). Further, a difference Q3 between MIU values (Q1-Q2) was calculated.

[3] Pattern (A)

The presence or absence of the fiber cake portion was visually confirmed for each nonwoven fabric sample.

[ Table 1]

[ Table 2]

As shown in tables 1 and 2, in examples 1 to 13, the difference T3 between the thickness T1 at the position where the fiber block portions are arranged and the thickness T2 at the position where the fiber block portions are not arranged is smaller than in comparative examples 1 and 2, and the bulkiness of the nonwoven fabric as a whole is excellent. In particular, in the examples, the nonwoven fabric obtained by calendering the web and then performing the heat treatment process was thicker than the nonwoven fabric calendered after calendering, and the nonwoven fabric had a good texture of the fiber mass portion.

In examples 1 to 13, while the fiber block pattern was confirmed, the average friction coefficient Q1 at the position where the fiber block portion was disposed, the average friction coefficient Q2 at the position where the fiber block portion was not disposed, and the difference Q3 therebetween were all smaller than those of comparative examples 1 and 2, and a soft touch feeling was achieved for the nonwoven fabric as a whole.

As described above, examples 1 to 13 had excellent bulkiness and soft texture, and had a pattern, thereby having excellent aesthetic properties.

The present invention has been described in connection with the embodiments and examples thereof, but it is not intended to be limited to the details of the description so long as the utility model is not specifically defined, but rather should be construed broadly within its spirit and scope as defined in the appended claims.

Description of the reference numerals

1 fiber layer

2 fibrous layer

7 fiber block part

8 fiber block layer (layer with fiber block part)

9 non-fiber block layer (layer without fiber block part)

10 Hot-air nonwoven fabric for absorbent article

Apparatus for producing hot-air nonwoven fabric for 100 absorbent article

101. 102 fiber opening part

103. 104 comb part

105 laminated web forming section

106 web calendering section

106A, 106B calender roll

107 heat treatment part (Hot air processing part)

117 first hot air processing part

127 second hot air processing part

108 cutting/splitting part

71. 72 raw material fiber

81. 82 Single layer fiber net (or fiber net)

90 laminated fiber web

95 by web calendering.

Claims

1. A through-air nonwoven fabric for an absorbent article, which is a through-air nonwoven fabric in which 2 or more fiber layers are laminated, has at least 1 fiber layer containing thermoplastic fibers and having a fiber block portion formed of thermoplastic fibers.

2. The through-air nonwoven fabric for an absorbent article according to claim 1, wherein when the thickness of the through-air nonwoven fabric measured under a pressure of 7.64kPa at a position where the fiber mass section is arranged is T1 and the thickness of the through-air nonwoven fabric measured under the same pressure at a position where the fiber mass section is not arranged is T2, the difference T3 in thickness defined by T3 ═ T1-T2 is 0.3mm or less.

3. The air-through nonwoven fabric for an absorbent article according to claim 2, wherein the difference T3 is 0.2mm or less.

4. The air-through nonwoven fabric for an absorbent article according to claim 1 or 2, wherein the fiber layer having the fiber block portion is an outermost layer of the air-through nonwoven fabric.

5. The air-through nonwoven fabric for an absorbent article according to claim 1 or 2, which has at least 1 fiber layer having no fiber block portion.

6. The air-through nonwoven fabric for an absorbent article according to claim 1 or 2, wherein the basis weight of the entire air-through nonwoven fabric is 15g/m²Above and 40g/m²The following.

7. The air-through nonwoven fabric for an absorbent article according to claim 1 or 2, wherein the average friction coefficient at a position where the fiber block portion is arranged in the air-through nonwoven fabric is 1.6 or more and 2.5 or less.

8. The through-air nonwoven fabric for an absorbent article according to claim 7, wherein the difference between the average friction coefficient at a position where the fiber block portion is arranged and the average friction coefficient at a position where the fiber block portion is not arranged in the through-air nonwoven fabric is 0.7 or less.

9. The through-air nonwoven fabric for an absorbent article according to claim 1 or 2, wherein the fiber block portion has a flat shape flattened in the thickness direction of the nonwoven fabric in a cross section in the thickness direction of the nonwoven fabric.

10. An absorbent article comprising the air-through nonwoven fabric for an absorbent article according to any one of claims 1 to 9.

11. An absorbent article comprising the absorbent article through-air nonwoven fabric according to any one of claims 1 to 9 disposed on the outermost layer on the skin surface side of the absorbent article, and a fiber layer having the fiber block portion disposed facing the skin surface side.

12. The absorbent article according to claim 10 or 11, having the air-through nonwoven fabric as a topsheet.