KR102177357B1 - Air-through nonwoven fabric for absorbent articles - Google Patents

Abstract

An air-through nonwoven fabric in which two or more fibrous layers are laminated, comprising a thermoplastic fiber and having at least one fibrous layer having a fiber mass portion.

Description

Air-through nonwoven fabric for absorbent articles

The present invention relates to an air-through nonwoven fabric for absorbent articles.

Since the air-through nonwoven fabric is formed by thermally fusion bonding the intersections of fibers by spraying hot air in an air-through method, it is possible to obtain a relatively thick and comfortable feel. Therefore, it is often used as a constituent member of an absorbent article. Various proposals have been made so far for the air-through nonwoven fabric for absorbent articles.

For example, in Patent Literature 1, from the viewpoint of imparting aesthetics by shape without impairing the touch, the difference between the thickness of a portion with and without a small fiber mass under pressure of 7.64 kPa An air-through nonwoven fabric having 1 mm or less is described. As a method for producing this air-through nonwoven fabric, it is described that a preliminary nonwoven fabric obtained by hot air spraying is subjected to calendering. In addition, Patent Document 2 describes an absorbent article provided with a nonwoven fabric having thermoplastic synthetic fibers and organic cotton fibers. In the nonwoven fabric, organic cotton fibers are arranged to form a plurality of fiber masses. This organic cotton fiber is not heat-sealed, and is fixed in the nonwoven fabric by entanglement of the fibers.

In Patent Document 3, from the viewpoint of improving the texture of the nonwoven fabric, it is described that the finished nonwoven fabric is subjected to a pressure treatment at a specific line pressure and temperature between a pair of rolls.

Patent Document 4 describes a processing method in which a fiber sheet wound in a roll shape is fed out, hot air is blown by an air-through method, and calendering is performed at a specific linear pressure.

Japanese Unexamined Patent Publication No. 2013-151774 Japanese Patent Application Publication No. 2017-202265 Japanese Laid-Open Patent Publication No. 60-126365 Japanese Patent Application Publication No. 2006-299480

The present invention provides an air-through nonwoven fabric for an absorbent article, comprising a thermoplastic fiber and having at least one fibrous layer having a fiber mass portion as an air-through nonwoven fabric in which two or more fibrous layers are laminated.

In addition, in the present invention, an opening step of forming a web by subjecting a thermoplastic fiber to a plurality of opening treatments, and a plurality of single layer webs obtained in the opening step are stacked to form a laminated web, and the laminated web is A process of obtaining an air-through nonwoven fabric by performing air-through processing by hot air, and a calendering process performed using a pair of calender rolls for one or more selected from the single-layer web, the laminated web, and the air-through nonwoven fabric It provides a method of manufacturing an air-through nonwoven fabric for absorbent articles having.

The above and other features and advantages of the present invention will become more apparent from the following description with reference to the accompanying drawings as appropriate.

1 is a cross-sectional view schematically showing a preferred embodiment of the air-through nonwoven fabric for absorbent articles of the present invention.
2 is a schematic configuration diagram showing a preferred embodiment of a manufacturing method and manufacturing apparatus for a nonwoven fabric of the present invention.
3 is a schematic configuration diagram showing another preferred embodiment of a heat treatment unit that performs an air-through step in the present embodiment.

The present invention relates to the provision of an air-through nonwoven fabric for absorbent articles that is excellent in bulkiness and soft touch and has a pattern.

In the manufacturing process of the air-through nonwoven fabric, when fibers are opened to form a web, fibers are sometimes entangled to form fiber masses. Particularly, the smaller the fiber diameter, the more likely the fibrous mass is to occur. When the fiber mass is directly subjected to an air-through processing step by hot air, it is cured by thermal fusion between the fibers.

In contrast, conventionally, as described in Patent Documents 1, 3 and 4, the finished nonwoven fabric is subjected to calendering to reduce the hardness. However, since the calendering process is a process in which the air-through nonwoven fabric is pressed between a pair of rolls, and the air-through nonwoven fabric after the pressure becomes thinner, there is room for improvement in bulk properties. Even if the nonwoven fabric as described in Patent Documents 1, 3 and 4 is subjected to hot air treatment after calendering, there is a limit to the recovery of the thickness of the nonwoven fabric once crushed, and there is room for further improvement. From this point of view, there is no suggestion regarding the recovery of bulk properties in Patent Document 3.

In the air-through nonwoven fabric for absorbent articles, it is strongly desired to achieve both the bulkiness and the soft feel as more excellent in terms of the absorbency and cushioning properties of the absorbent article.

On the other hand, the air-through nonwoven fabric for an absorbent article of the present invention is excellent in bulkiness and soft touch, and has a pattern. Further, according to the manufacturing method of the present invention, the air-through nonwoven fabric for absorbent articles can be manufactured with good precision.

Hereinafter, the air-through nonwoven fabric for absorbent articles of the present invention will be described with reference to the drawings.

The air-through nonwoven fabric for an absorbent article of the present invention can be applied to various absorbent articles that absorb body fluids by being attached to the body, and can be applied to various constituent members such as a top sheet in the absorbent article.

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

In addition, in the present invention, the "air-through nonwoven fabric" is one in which heat-fusible fibers are heat-fused at the intersection point and integrated. The air-through method is used to manufacture this nonwoven fabric. The air-through method refers to a method in which hot air is blown through a fiber web containing heat-fusible fibers in a penetrating manner, and the intersections of the webs are fused 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 two or more fibrous layers are laminated. Two layers of fiber layers to be laminated may be sufficient, and three or more layers may be used. By having two or more layers of the air-through nonwoven fabric for an absorbent article of the present invention, it becomes possible to make it a bulky nonwoven fabric beyond manufacturing limitations compared to the case where the nonwoven fabric is formed with one layer.

1 is a preferred embodiment of the air-through nonwoven fabric for an absorbent article of the present invention, in which two layers of fibrous layers (fibrous layer 1 and fibrous layer 2) are laminated for an absorbent article 10 (hereinafter, simply It is also referred to as nonwoven fabric (10)). The fibrous layer 1 and the fibrous layer 2 contain heat-sealable fibers, and the contact surfaces of both layers are joined over the entire area by fusion bonding of the heat-sealable fibers. Therefore, the nonwoven fabric 10 does not have a region where the fibrous layer 1 and the fibrous layer 2 are separated from each other. That is, the nonwoven fabric 10 is one sheet body in which the two layers are integrated.

The nonwoven fabric of the present invention may have various surface shapes such as an uneven surface, but like the nonwoven fabric 10 of the present embodiment shown in FIG. 1, both surfaces 10A and 10B (the surface of the fiber layer 1 and the fiber layer 2 It is preferable that the surface) of) is a flat shape. The nonwoven fabric 10 is a laminate of a plurality of fibrous layers, and has a flat shape on both sides, so that the smoothness of the surface and the cushioning feeling are both compatible and excellent. The flat shape means that the thickness difference between the concave portion and the convex portion on the surface of the nonwoven fabric is within 1 mm. Specifically, a nonwoven fabric is cut in the thickness direction with a razor blade, and a photograph of a cross section is taken using a microscope (manufactured by Keyence Corporation, VHX-900). In the photograph, the thickness of the portion where the upper surface of the nonwoven fabric is located at the uppermost side, that is, the convex portion, and the portion where the upper surface of the nonwoven fabric is located at the lowermost side, that is, the thickness of the concave portion, is measured, and this thickness difference is calculated. Take the average of 3 points.

The nonwoven fabric 10 has at least one fibrous layer 8 having a fibrous mass 7. Hereinafter, the fibrous layer (8) having the fibrous mass (7) is referred to as the fibrous mass layer (8). In FIG. 1, the fibrous mass layer 8 is disposed on the fibrous layer 1.

In the present invention, "fibrous mass" refers to a part of a node (thread bundle) formed by entanglement of fibers in the fibrous layer. In the fiber mass, the density of the fiber is higher than that of the surrounding part in the same fiber layer, so that the color (mainly white) density (brightness) of the fiber can be visually recognized as a lump (granular) that is higher than the surrounding part. have. The shape of the fiber mass is not particularly limited. In the present invention, the fiber agglomerate portion has a flat shape crushed in the thickness direction of the nonwoven fabric in a cross section in the thickness direction of the nonwoven fabric, and it is preferable that the fiber agglomerate surface on the nonwoven fabric surface side has a smooth structure. Thereby, the surface of the nonwoven fabric corresponding to the location of the fiber mass 7 becomes smooth, and it is felt that the surface feel of the nonwoven fabric 10 is more excellent.

The "fibrous mass layer (8)" refers to a layer having at least one fibrous mass. In the fibrous mass layer 8, it is not necessary that the fibrous mass 7 is filled, but is preferably dispersed and disposed.

The fiber mass layer 8 is not limited to the case where it exists only in the fiber layer 1 as shown in FIG. 1, It may exist in the fiber layer 2 instead of the fiber layer 1, and may exist in both layers. From the viewpoint of a soft touch, it is preferable to be in any one layer. From the viewpoint of enhancing the visual effect of the shape of the fiber mass 7 when the nonwoven fabric 10 is viewed in a plan view, it is preferable that both layers have the fiber mass layer 8. As a result, the shape of the fiber mass 7 appears to be dispersed not only in the planar direction of the nonwoven fabric 10 but also in the thickness direction, and the concentration of the fiber mass 7 visible in the thickness direction becomes softer as it is on the lower layer side. It looks changed, and a shape with depth is seen. When there is a fiber mass layer 8 in both layers of the fibrous layer 1 and the fibrous layer 2, the fibrous mass 7 of the fibrous layer 1 and the fibrous mass 7 of the fibrous layer 2 do not overlap in the thickness direction. It is preferable that the arrangement is not. In addition, the fibrous mass layer 8 may be disposed on the entire fibrous layer (fibrous layer 1 or fibrous layer 2) on which the fibrous mass layer 8 is disposed, or may be disposed in a part thereof.

As described above, the nonwoven fabric 10 is one obtained by fusion bonding fibers of the layer interface over the entire area where the fibrous layer 1 and the fibrous layer 2 abut. Therefore, even if the nonwoven fabric 10 includes the fibrous mass layer 8 with the fibrous mass 7, it is felt that the entire nonwoven fabric 10 in which a plurality of fibrous layers are integrated over the entire layer interface has a thickness, It has excellent bulkiness and soft touch. And when the nonwoven fabric 10 is viewed from the top, it has a pattern due to the difference in color and shade of the part with and without the fiber mass. The shape of the fiber mass 7, particularly the shape of the fiber mass 7 having a flattened thickness, makes the nonwoven fabric 10 aesthetically pleasing.

It is preferable that the nonwoven fabric 10 of the present embodiment has fine fibers having a fiber diameter of 1 dtex or more and 2.2 dtex or less, and coarse fibers having a larger fiber diameter than the fine fibers. Thereby, it is possible to achieve both the improvement of the soft touch of the nonwoven fabric by the fine fibers and the improvement of the bulk property by the thick fibers. In addition, having thick fibers is preferable because it can contribute to the improvement of the thickness recovery of the nonwoven fabric after pressing.

Moreover, it is preferable that the fiber mass layer 8 contains the said fine fiber. In this case, the said fine fiber may be contained in the fiber ingot part 7 or may be contained in a part other than the fiber ingot part 7. Thereby, the hardness around the fiber mass 7 felt when the nonwoven fabric 10 is touched is alleviated by the presence of the fine fibers. In this case, as for the nonwoven fabric 10, it is preferable that the fibrous layer 1 having the fibrous mass layer 8 containing the fine fibers is disposed toward the skin-contacting 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 more preferably 2 dtex or less, and even more preferably 1.5 dtex or less. Further, the fiber diameter of the fine fibers is more preferably 1 dtex or more, and still more preferably 1.2 dtex or more, from the viewpoint of spinning property of the card machine on the production of the nonwoven fabric. Specifically, the fiber diameter of the fine fibers is preferably 1 dtex or more and 2 dtex or less, and more preferably 1.2 dtex or more and 1.5 dtex or less.

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

In addition, the nonwoven fabric 10 of the present embodiment includes at least one fibrous layer 9 (hereinafter referred to as non-fibrous mass layer 9) having no fibrous mass 7 in addition to the fibrous mass layer 8 described above. It is preferable to have a layer. For example, as shown in FIG. 1, the form in which the fibrous layer 1 is a fibrous mass layer 8, and the fibrous layer 2 is a non-fibrous mass layer 9 is mentioned.

When the nonwoven fabric 10 has the fiber mass layer 8 and the non-fibrous mass layer 9, it is preferable to have coarse fibers having a fiber diameter of more than 2.2 dtex and 7 dtex or less, and fine fibers having a fiber diameter smaller than that of the coarse fibers. It is preferable that the fiber diameter of the fine fibers is in the above-described range. Thereby, it is possible to achieve both the improvement of the soft touch of the nonwoven fabric by the fine fibers and the improvement of the bulk properties by the thick fibers, and it is preferable that it can contribute to the improvement of the thickness recovery of the nonwoven fabric after pressing.

In addition, it is preferable that the non-fibrous mass layer 9 contains the coarse fibers. When the non-fibrous mass layer 9 contains the coarse fibers, it is possible to improve bulkiness and provide a cushioning feeling. In this case, as for the nonwoven fabric 10, it is preferable that the fibrous layer 2 having the non-fibrous mass layer 9 containing coarse fibers is disposed toward the non-skin abutting surface side of the absorbent article.

The fiber diameter of the coarse fibers is more preferably more than 2.2 dtex, and still more preferably 4.4 dtex or more, from the viewpoint of improving the bulk properties and compression recovery properties of the nonwoven fabric 10. Further, the fiber diameter of the coarse fibers is more preferably 5.5 dtex or less, and still more preferably 5 dtex or less, from the viewpoint of texture on the side of the fiber ingot layer. Specifically, the fiber diameter of the coarse fiber is preferably more than 2.2 dtex and less than 5.5 dtex, more preferably more than 4.4 dtex and less than 5 dtex.

The content of the coarse fibers in the non-fibrous mass layer 9 is, as a mass ratio, preferably 50% by mass or more, more preferably 80% by mass or more, from the viewpoint of improving the bulk properties and compression recovery properties of the nonwoven fabric 10. It is preferable, and 100 mass% is more preferable.

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

(Measurement method of fiber diameter of fine fibers and coarse fibers, measurement method of content of fine fibers in fiber mass layer (8), method of measurement of content of coarse fibers in non-fibrous mass layer (9))

In an arbitrary place of the nonwoven fabric, the fiber mass layer side and the surface side of the non-fibrous mass layer are observed at a magnification of 3 points at 100 magnification using a scanning electron microscope (JCM-5100 manufactured by Nippon Electronics Co., Ltd.).

Fiber diameter: Measure the fiber diameter within the area of 1 mm2. In the measurement of the fiber diameter, 20 points are measured for each different fiber for one point, and the average value is taken as each fiber diameter. In addition, the fluctuation width of the fiber diameter in the nonwoven fabric for absorbent articles is usually a minute difference such that it is difficult to confirm even when observed with the scanning electron microscope. For example, in general, the fluctuation range of the fiber diameter is about 6% in terms of the fiber standard. Therefore, as long as it is a value obtained by measuring 20 points as described above and averaged, each fiber diameter can be used.

Fiber Content Rate: First, place the OHP film on the image within 1 ㎟ that was observed enlarged, and paint all black for each fiber diameter. This sheet is subjected to image analysis processing using image analysis software (NexusNewQube). 2 The dimensional treatment is performed and the area is calculated. The area of each fiber is measured, and the ratio is taken as the content rate of each fiber.

(Measurement member sampling method)

At the time of the above measurement, in the case of taking out a constituent member (for example, a surface material) to be measured from the absorbent article and performing evaluation measurement, it is obtained by the following method. That is, when the constituent member is fixed to another constituent member by means of an adhesive or the like, the constituent member is easily peeled off by filling the adhesive with liquid nitrogen. When the constituent member is fixed to another constituent member by fusion or the like, the constituent member is peeled off by hand, or the fused portion is cut off with a cutter knife or the like and peeled off. This method is similarly used in other measurement methods.

In the nonwoven fabric 10, it is preferable that the average fiber diameter of the non-fibrous mass layer 9 is larger than that of the fibrous mass layer 8. Thereby, the fiber mass layer 8 becomes a layer which improves the soft touch of the nonwoven fabric 10, and the non-fibrous mass layer 9 becomes a layer which improves the bulk property and thickness recovery property of the nonwoven fabric 10. As a result, with respect to the nonwoven fabric 10, the fibrous mass layer 8 and the non-fibrous mass layer 9 can be functionally shared layer by layer, and both layers cooperate in the thickness direction to improve the texture of the nonwoven fabric 10 as a whole. It can be made good. From this point of view, it is preferable that the nonwoven fabric 10 has the fine fibers and the coarse fibers, and the fiber mass layer 8 contains the fine fibers, since the above action can be more clearly expressed. Further, it is more preferable from the same viewpoint that the non-fibrous mass layer 9 contains the coarse fibers.

The difference (V3) (= V1-V2) between the average fiber diameter (V1) of the non-fibrous mass layer (9) and the average fiber diameter (V2) of the fibrous mass layer (8) is the viewpoint of the above functional division in the nonwoven fabric In this, more than 0 dtex is preferable, 2.2 dtex or more is more preferable, and 3 dtex or more is still more preferable. Further, from the same viewpoint as described above, the difference (V3) is preferably 5.6 dtex or less, more preferably 4 dtex or less, and still more preferably 3.5 dtex or less. Specifically, the difference (V3) is preferably more than 0 dtex and 5.6 dtex or less, more preferably 2.2 dtex or more and 4 dtex or less, and still more preferably 3 dtex or more and 3.5 dtex or less.

(Measurement method of the average fiber diameter of the fibrous mass layer (8) and the non-fibrous mass layer (9))

Based on the above (measurement method of fiber diameter of fine fibers and coarse fibers, method of measuring the content of fine fibers in the fiber mass layer (8), method of measuring the content of coarse fibers in the non-fibrous mass layer (9)) The calculated fiber diameter and the content rate are multiplied, and the sum is taken as the average fiber diameter of each layer.

Moreover, in the nonwoven fabric 10, it is preferable that the basis weight of the non-fibrous mass layer 9 is larger than that of the fibrous mass layer 8. Thereby, the bulk of the non-fibrous mass layer 9 is larger than that of the fibrous mass layer 8, and the hardness due to the fibrous mass 7 becomes more difficult to detect. In addition, the bulkiness of the non-fibrous mass layer 9 acts to increase the cushioning property of the nonwoven fabric 10, so that when the fibrous mass layer 8 is pressed and crushed in the thickness direction, the stress on the skin of the fibrous mass 7 Can be further reduced and a good texture can be further improved. Along with this difference in basis weight, it is preferable that the nonwoven fabric 10 has the fine fibers and the coarse fibers, and the fiber mass layer 8 contains the fine fibers, since the above action can be more clearly expressed. Further, it is more preferable from the same viewpoint that the non-fibrous mass layer 9 contains the coarse fibers. Further, it is preferable that the nonwoven fabric 10 has a larger average fiber diameter of the non-fibrous mass layer 9 than the fibrous mass layer 8.

The difference (Y3) (= Y1-Y2) between the basis weight (Y1) of the non-fibrous mass layer 9 and the basis weight (Y2) of the fibrous mass layer (8) is from the viewpoint of improving the cushioning property and good texture of the entire nonwoven fabric. , More than 0 g/m 2 is preferable, 3 g/m 2 or more is more preferable, and 5 g/m 2 or more is still more preferable. Further, the difference (Y3) is preferably 20 g/m 2 or less, more preferably 15 g/m 2 or less, and still more preferably 10 g/m 2 or less, from the viewpoint of improving texture. Specifically, the difference (Y3) is preferably more than 0 g/m 2 and not more than 20 g/m 2, more preferably 3 g/m 2 or more and 15 g/m 2 or less, and 5 g/m 2 or more and 10 g/m 2 or less Is more preferred.

(Measurement method of basis weight of fibrous mass layer (8) and non-fibrous mass layer (9))

1) The value obtained by converting the mass of the nonwoven fabric to be measured into per 1 m2 is taken as the total basis weight.

The mass (w) of the nonwoven fabric to be measured is measured, and the value calculated by the following equation is taken as the total basis weight (W).

W = (1000000/LMD/LCD)w = 25w

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

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

When a sample is collected from a product, if the above size cannot be collected, it is cut within the range that can be collected and converted into 1 ㎡.

2) Basis weight of each layer: Peel off each layer of the nonwoven fabric to be measured carefully, and convert the mass into 1 ㎡ as the basis weight of each layer.

[Unit: number of digits] g/m²: Calculate to the first decimal place by rounding off the second decimal place.

[Measurement number] Measure 3 points and take the average value as each basis weight.

The basis weight of the nonwoven fabric 10 as a whole is preferably 15 g/m 2 or more from the viewpoint of having excellent bulkiness and soft touch and good texture in a structure in which two or more fibrous layers are laminated and integrated. It is more preferably g/m 2 or more, and even more preferably 20 g/m 2 or more. In addition, the basis weight of the nonwoven fabric 10 as a whole is preferably 40 g/m2 or less, more preferably 30 g/m2 or less, and further 25 g/m2 or less, from the viewpoint of the release ability of the nonwoven fabric production phase. desirable. Specifically, the basis weight of the nonwoven fabric 10 as a whole is preferably 15 g/m 2 or more and 40 g/m 2 or less, more preferably 18 g/m 2 or more and 30 g/m 2 or less, and 20 g/m 2 or more and 25 g/ M2 or less is more preferable. In addition, the basis weight of the nonwoven fabric 10 as a whole is measured in accordance with the above-described (Measurement method of the basis weight of the fibrous mass layer 8 and the non-fibrous mass layer 9).

With respect to such a nonwoven fabric 10, the thickness of the nonwoven fabric 10 measured under a pressure of 7.64 kpa at the position where the fiber mass 7 is disposed is T1, and the fiber mass 7 is not disposed. At the position, when the thickness of the nonwoven fabric 10 measured under the same pressure is T2, the smaller the difference in thickness (T3) defined by T3 = T1-T2, the smaller the hardness resulting from the fiber mass 7 It becomes difficult to perceive. As a result, a cushioning feeling accompanied by bulkiness by laminating a plurality of fibrous layers is easily felt, and a soft touch is easily perceived. From this viewpoint, the difference T3 in the thickness is preferably 0.4 mm or less, more preferably 0.3 mm or less, further preferably 0.2 mm or less, and most preferably 0 (zero) mm.

In addition, the term "position where the fiber mass is arranged" means the presence of the fiber mass 7 on the surface of the nonwoven fabric 10 when viewed from the side on the side to be pressed from the surface of the nonwoven fabric 10. Refers to a location where can be confirmed (hereinafter, it has the same meaning in this specification). In addition, "the position where the fiber lump part is not arranged" refers to a position in which the existence of the fiber lump part 7 cannot be visually confirmed in the above plane view (hereinafter, it has the same meaning in this specification). .

(Measurement method of thickness of nonwoven fabric under pressure of 7.64 kPa)

Using a dial gauge type thickness gauge (JIS B 7503 (1997), PEACOCK's UPRIGHT DIAL GAUGE 7.64 kPa pressure gauge's tip is a Φ5 mm flat disk), the thickness of the position where the fiber mass is placed in the nonwoven fabric (T1 ), the thickness (T2) of the nonwoven fabric under dynamic pressure at a position where the fiber mass is not disposed is measured, and the difference in thickness defined by T3 = T1-T2 is obtained. The measurement is performed at 5 points or more for T1 and T2, respectively. Then, the average value of T1 and the average value of T2 are calculated, and the difference is set to T3. In addition, the load 7.64 kpa is a measurement condition set in order to clarify the existence of the fiber mass.

Moreover, the soft touch of the nonwoven fabric 10 is represented by the value of the average coefficient of friction, and the smaller the value, the better the touch. In general, the value of the average coefficient of friction is smaller in the portion where the fibrous mass portion 7 is not disposed than the portion in which the fibrous mass portion 7 is disposed. However, in the nonwoven fabric 10 of the present embodiment, a plurality of fiber layers are laminated in the thickness direction and integrated, so that the average coefficient of friction is small at the position where the fiber mass 7 is disposed. The average coefficient of friction (Q1) at the position where the fiber mass 7 of the nonwoven fabric 10 is disposed is preferably 2.5 or less, more preferably 2.4 or less, and 2.3 or less from the viewpoint of maintaining a soft touch. It is more preferable, and 1.6 or more is practical. Specifically, the average coefficient of friction (Q1) at the position where the fiber mass 7 of the nonwoven fabric 10 is arranged is preferably 1.6 or more and 2.5 or less, more preferably 1.6 or more and 2.4 or less, and 1.6 or more and 2.3 The following are more preferable.

In addition, the average coefficient of friction (Q1) at the position where the fiber mass 7 of the nonwoven fabric 10 is disposed and the average coefficient of friction at the position where the fiber mass 7 of the nonwoven fabric 10 is not disposed The difference (Q3) (= Q1-Q2) of (Q2) 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, from the viewpoint of maintaining a soft feel. , 0 (zero) is most preferred.

(Measurement method of average coefficient of friction)

Using a KES-FB4 surface tester manufactured by Catotech, cut the nonwoven fabric to be measured into 15 cm horizontally and vertically, and with respect to the measurement surface, under the conditions of SENS: 2 Х 5 and load 4.9 kPa, the fiber mass was arranged. The MIU value at the position and the position where the fiber mass is not arranged is measured. The measurement is performed at each of 5 points or more in two directions (typically MD direction and CD direction) that are each orthogonal, and they are taken as the average value. The MIU value is an average coefficient of friction, and the larger the value is, the more rough the surface is and the texture is poor, and the smaller one is smoother and the texture is good.

It is preferable that the above-described fibrous mass layer 8 is the outermost layer of the nonwoven fabric 10. In this case, a case in which the fiber ingot layer 8 may be present only on one of the front and back surfaces of the nonwoven fabric 10, and the fiber ingot layer 8 is present on both the front and back surfaces of the nonwoven fabric 10. It may be the case. When the fiber mass layer 8 is the outermost layer of the nonwoven fabric 10, the visual effect is maximized.

From the viewpoint of maintaining the soft touch of the nonwoven fabric 10, the number of fiber masses 7 disposed on the nonwoven fabric 10 is determined by viewing the front and back surfaces of the nonwoven fabric 10 in a plan view. Viewed from) As an average for each 10 cm square region, 50 or less is preferable, 40 or less is more preferable, and 30 or less is still more preferable. On the other hand, from the viewpoint of imparting a shape, the number of fiber masses 7 disposed on the nonwoven fabric 10 is as viewed from the front and back surfaces of the nonwoven fabric 10 (when viewed from a plan view while each fiber layer is laminated) As an average for every 10 cm square region, 5 or more are preferable, 10 or more are more preferable, and 20 or more are still more preferable. The number of fibrous masses 7 is, specifically, an average of 10 cm square areas when the front and back surfaces of the nonwoven fabric 10 are viewed in a plan view (when viewed in a plan view in a state in which each fiber layer is laminated), and is 5 or more. 50 or less are preferable, 10 or more and 40 or less are more preferable, and 20 or more and 30 or less are still more preferable.

In addition, from the viewpoint of reducing the chance of contact between the skin and the fibrous masses 7, the number of fibrous masses 7 in the fibrous layer serving as the skin face side of the absorbent article among the laminated fibrous layers is the skin face side. The average of the fiber layer for each 10 cm square area viewed in plan view is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less. It is preferable that the number of fibrous masses 7 in the fibrous layer serving as the skin surface side of the absorbent article is 1 or more. The number of fibrous masses 7 in the fibrous layer serving as the skin surface side of the absorbent article is, specifically, an average for each 10 cm square area of the skin surface side fibrous layer as viewed in plan, and is 1 or more and 30 or less. It is preferable, and 1 or more and 20 or less are more preferable, and 1 or more and 10 or less are still more preferable.

In addition, from the viewpoint of forming a pattern with a depth, the number of fiber masses 7 disposed on the fiber layer serving as the non-skin surface side of the absorbent article among the two layers stacked is shown in plan view of the fiber layer serving as the non-skin surface side. As an average for each 10 cm square area, 3 or more are preferable, 8 or more are more preferable, and 15 or more are still more preferable.

The size (area) of the nonwoven fabric 10 of the individual fiber mass portions 7 when viewed in plan view is preferably 10 mm 2 or less, more preferably 8 mm 2 or less from the viewpoint of maintaining the soft touch of the nonwoven fabric 10 It is preferable, and 6 mm 2 or less is more preferable. On the other hand, the size of the nonwoven fabric 10 of the individual fiber mass portions 7 when viewed in a plan view is preferably 1 mm 2 or more, more preferably 2.5 mm 2 or more, and 4 mm 2 or more from the viewpoint of imparting a shape. More preferable. Specifically, the size (area) of the nonwoven fabric 10 of the individual fiber mass portions 7 when viewed in a plan view is preferably 1 mm 2 or more and 10 mm 2 or less, more preferably 2.5 mm 2 or more and 8 mm 2 or less, 4 mm2 or more and 6 mm2 or less are more preferable.

In addition, the size of the nonwoven fabric 10 of the fiber mass portion 7 disposed on the skin surface side of the absorbent article when viewed from a plan view is preferably 9 mm 2 or less, more preferably 7 mm 2 or less, and 5 mm 2 The following are more preferable.

In addition, from the viewpoint of forming a pattern with a depth, the size of the nonwoven fabric 10 of the fiber mass 7 disposed on the fiber layer serving as the non-skin side of the absorbent article in plan view among the two laminated layers, 2 mm 2 or more is preferable, 3 mm 2 or more is more preferable, and 5 mm 2 or more is still more preferable.

The size (thickness) of the individual fiber masses 7 in the thickness direction of the nonwoven fabric 10 is a ratio to the thickness of the nonwoven fabric 10 from the viewpoint of maintaining the soft touch of the nonwoven fabric 10, 50 % Or less is preferable, 40% or less is more preferable, and 30% or less is still more preferable. On the other hand, the size (thickness) of the individual fiber masses 7 in the thickness direction of the nonwoven fabric 10 is a ratio to the thickness of the nonwoven fabric 10 from the viewpoint of texture, and is small within a range of more than 0%. The smaller it is, the more preferable. The size (thickness) of the individual fiber masses 7 in the thickness direction of the nonwoven fabric 10 is specifically, as a ratio to the thickness of the nonwoven fabric 10, and is preferably more than 0% and not more than 50%. And more than 0% and 40% or less are more preferable, and more preferably more than 0% and 30% or less.

In addition, from the viewpoint of mitigating the hardness felt when the skin comes into contact with the fibrous mass 7 by a plurality of laminated and integrated fibrous layers, of the two laminated layers, a fibrous mass disposed on the fibrous layer on the skin side of the absorbent article The size in the thickness direction of the nonwoven fabric 10 of (7) is a ratio with respect to the thickness of the nonwoven fabric 10, preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less. .

In addition, the size (thickness) of the individual fiber mass 7 in the thickness direction of the nonwoven fabric 10 is preferably 1 mm or less, more preferably 0.8 mm or less, and 0.5 mm from the same viewpoint as above. The following are more preferable, and the smaller the value is more preferable in the range of more than 0 mm. The size (thickness) of the individual fiber masses 7 in the thickness direction of the nonwoven fabric 10 is, specifically, more than 0 mm and 1 mm or less, more preferably more than 0 mm and 0.8 mm or less, More than 0 mm and 0.5 mm or less are more preferable.

(Measurement method of number, area and thickness of fiber mass)

From the observation target surface of the nonwoven fabric cut to 10 cm in width and length (for example, the surface 10A in the nonwoven fabric 10), a photograph is taken using a microscope (manufactured by Keyence Corporation, VHX-900). The image data (jpeg) is subjected to image analysis processing using image analysis software (NexusNewQube). 2 The dentifrice treatment is performed, and the number and area of the ingots are calculated. Further, the entire mass is cut in the thickness direction with a razor blade, and the cross section is observed with the microscope to measure the thickness of the nonwoven fabric and the fiber mass.

The air-through nonwoven fabric for absorbent articles of the present invention is used as a component of an absorbent article. The absorbent article includes, for example, diapers, sanitary napkins, urine collection pads, panty liners, and other various items having a function of absorbing and holding human excrement.

The air-through nonwoven fabric for an absorbent article of the present invention is used as various members of an absorbent article according to its function, and is inserted into the absorbent article. For example, when it has liquid permeability, it is inserted as a top sheet, and when it has water repellency, it is inserted as a side sheet. Moreover, it is made thinner and softer, and is inserted as an exterior material which improves the feel of the outer side (wearing side) of an absorbent article such as a diaper.

Among them, the air-through nonwoven fabric for an absorbent article of the present invention is the skin of an absorbent article from the viewpoint of making it easier to detect the texture of the nonwoven fabric having excellent bulkiness and soft touch with the skin and making the shape of the nonwoven fabric easier to recognize with the naked eye. It is preferable to arrange|position on the outermost layer on the surface side, and to arrange|position the fiber mass layer 8 toward the skin surface side. For example, a top sheet and a side sheet may be cited. In particular, it is preferable that the air-through nonwoven fabric for absorbent articles of the present invention is disposed on the absorbent article as the top sheet.

Next, a preferred embodiment of the method for producing the air-through nonwoven fabric for absorbent articles of the present invention will be described. Here, it demonstrates as a manufacturing method of the nonwoven fabric 10 of the above-mentioned embodiment. However, the fibrous layer to be laminated is not limited to two layers (fibrous layer 1 and fibrous layer 2), and three or more fibrous layers may be laminated.

In the manufacturing method of this embodiment, it has the following process 501 and process 502.

Step 501: An opening step of forming a web by subjecting the thermoplastic fiber to an opening treatment a plurality of times.

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

In addition, in the manufacturing method of this embodiment, it has the following process 503.

Step 503: A calendering process performed using a pair of calender rolls for one or more selected from the single layer web, the laminated web, and the air-through nonwoven fabric.

Step 503 is after step 501 and is performed in any one or more of before step 502, during step 502, and after step 502.

2 shows a manufacturing apparatus 100 preferably used in the manufacturing method of the nonwoven fabric 10 of the present embodiment. The manufacturing apparatus 100 includes, from an upstream side to a downstream side, opening portions 101 and 102 of an amount of fiber material used as a raw material for a nonwoven fabric, carding portions 103 and 104 forming a web of fibers, and a single layer web obtained by carding. A laminated web forming part 105 which conveys and laminates the laminated web, a web calender part 106 which performs a pressurization treatment on the laminated web, and a heat treatment part (air-through processing part) 107.

In the manufacturing apparatus 100, the step 501 is performed in the opening portions 101 and 102 and the carding portions 103 and 104. The step 502 is carried out in the laminated web forming portion 105 and the heat treatment portion 107.

In the manufacturing apparatus 100, the step 503 is performed in the web calender part 106. The web calender part 106 is disposed between the laminated web forming part 105 and the heat treatment part 107, and the step 503 is performed as a web calendering process for the laminated web in the middle of the step 502.

Each of the opening portions 101 and 102 has a device for opening the thermoplastic fibers used as raw materials for the fibrous layers 1 and 2 and sending them to the following carding portions 103 and 104, respectively. When using the above-described fine fibers and coarse fibers having a specific fiber diameter, it is preferable to open the fibers by dividing into fine fibers and coarse fibers. In FIG. 2, raw fibers (fine fibers) 71 are introduced into the opening portion 101 to open (arrow 171), and raw fibers (coarse fibers) 72 are introduced into the opening portion 102 to open. (Arrow 172).

As the raw material fiber (fine fiber) 71 and the raw material fiber (coarse fiber) 72, various thermoplastic fibers used in the air-through nonwoven fabric can be used. For example, as the core sheath structure, a composite fiber in which the resin component of the sheath has a lower melting point than that of the resin component of the core may be mentioned.

In the carding portions 103 and 104, the fibers opened at the opening portions 101 and 102, respectively, are received (arrows 173 and 174), and single-layer webs 81 and 82 are formed. Specifically, the aggregates of fibers opened by the opening portions 101 and 102 are combed and then opened again to form a sheet-like web. In the carding part 103, a single-layer web 81 based on the raw material fibers (fine fibers) 71 is formed, and in the carding part 104, a single-layer web based on the raw material fibers (coarse fibers) 72 ( 82) is formed.

In the carding portions 103 and 104, various card machines commonly used in the production of air-through nonwoven fabrics can be used without particular limitation. For example, a parallel card machine, a semi-random card machine, a random card machine, and a combination of a cross layer and a drafter may be mentioned. Moreover, as a card machine, what was provided with three types of rolls of a main cylinder roll covered with a toothed metallic wire, a walker roll, and a stripper roll is mentioned. Opening can be performed by combing the aggregate of fibers between the main cylinder roll and the walker roll and stripper roll. By arranging a plurality of sets of worker rolls and stripper rolls with respect to the main cylinder roll, it is possible to perform the opening treatment a plurality of times in the card machine of each of the carding units 103 and 104.

As described above, a plurality of opening processing is performed in both the opening portions 101 and 102 and the carding portions 103 and 104.

In the manufacturing method of this embodiment, the opening process (step 501) of forming a web by subjecting the thermoplastic fiber to a plurality of opening treatments in the above-described opening portions 101 and 102 and carding portions 103 and 104 is performed. .

Next, in the laminated web forming part 105, the single-layered web 82 formed in the carding part 104 is laminated on the single-layered web 81 formed in the carding part 103, and the laminated web 90 is formed. To form.

Specifically, the single-layer web 81 is taken out from the carding portion 103 along the carry-out belt 103A, and is placed on the conveyance belt 105A. The conveyance belt 105A conveys the single layer web 81 downstream. Moreover, the single layer web 82 is taken out from the carding along the carrying belt 104A, guided to the conveyance belt 105A, and laminated on the single layer web 81 during conveyance. The laminated web 90 thus formed is further conveyed downstream along the conveying belt 105A. In addition, in the laminated web 90, 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 from raw material fibers (coarse fibers) 72, and the web 81 is formed from raw material fibers (fine fibers) 71. Therefore, the average fiber diameter of the web 82 is larger than the average fiber diameter of the web 81. Further, from this point of view, the web 81 becomes a fiber mass layer 8 containing fine fibers of the specific fiber diameter in the finished nonwoven fabric 10. The web 82 can be made into a non-fibrous mass layer 9 containing thick fibers of the specific fiber diameter in the finished nonwoven fabric 10. In addition, in the finished nonwoven fabric 10, the basis weight of the non-fibrous mass layer 9 is larger than that of the fibrous mass layer 8, so that the mass of the fibers supplied from the opening portion 102 to the carding portion 104 is determined by the opening portion ( It can be realized by making it more than the feed mass of the fiber from 101) to the carding part 103.

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

For fibers of different fiber diameters, it is preferable that fine fibers having a fiber diameter of 1 dtex or more and 2.2 dtex or less are used. Moreover, it is more preferable that the fiber diameter of the fine fiber is in the range of the fiber diameter described above.

In the web calender part 106, web calendering is performed in which the laminated web 90 that has been conveyed is sandwiched between a pair of calender rolls 106A and 106B and pressed (hereinafter, simply referred to as ``calendar processing''). have). Thereby, the web surface of the part where the fiber agglomeration part 7 exists can be made smooth, and the hardness of the fiber agglomerate part 7 can be reduced.

In particular, in the manufacturing method of the present embodiment, since calendering is performed on the laminated web 90 before nonwoven fabrication, the fibers are still not fused and fixed, and the fibers can be largely moved. That is, in the calendering process in the present embodiment, there is no fear of causing peeling or destruction of fibers in the fusion portion between fibers, and gathering in the fiber mass portion 7 while maintaining the state of the fibers satisfactorily. The fibers are preferably separated (to widen the gap between the fibers), so that the fiber mass 7 can be satisfactorily crushed. Thereby, the effect of reducing the hardness of the fiber ingot 7 increases. In addition, the pressure in the thickness direction by calendering is easy to disperse the fibers of the fiber mass 7 in any of the laminated nonwoven webs 81 and 82, so that the entire laminated web 90 The effect of reducing the hardness of the fiber ingot 7 is enhanced (hereinafter, the laminated web subjected to web calendering is sometimes referred to as the laminated web 95). In addition, in a series of manufacturing processes, by performing the air-through processing described later after the calender processing, it becomes possible to utilize the air-through processing as a recovery treatment for the thickness of the nonwoven fabric. That is, in the present embodiment, the processing step performed in this order is meaningful in recovering the thickness of the laminated web 95, having a larger volume, excellent soft touch, and forming a pattern.

In the heat treatment unit 107, the laminated web 95 subjected to web calendering is subjected to air through processing by hot air.

Specifically, the heat treatment unit 107 has a hood 107A and a conveyor belt 107B provided with a breathable net circumferentially around the hood 107A. In the hood 107A, hot air is blown toward the conveyor belt 107B from above (arrow F shown in Fig. 2). In the conveyor belt 107B, the injected hot air is blown out by the air permeable net. The laminated web 95 subjected to the web calendering process is extruded into the heat treatment unit 107 by roll rotation of the web calender unit 106. In the heat treatment unit 107, the laminated web 95 is conveyed into the hood 107A by a conveyor belt 107B. With respect to the laminated web 95 in the hood 107A, hot air heated to a predetermined temperature from above the laminated web 95 (that is, above the web 82) in the thickness direction is blown by a penetrating method. That is, air-through processing is performed on the laminated web 95. Thereby, in the laminated web 95, the spacing between the fibers in the fiber mass 7 is widened by the web calendering process described above, and the hardness of the fiber mass 7 is reduced, while the hot air The intersections of fibers are fused by spraying. Thereby, the air-through nonwoven fabric 10 for absorbent articles of this embodiment is obtained.

As described above, in the manufacturing method of the present embodiment, with respect to the single-layer webs 81 and 82 obtained through the opening step of the step 501, the laminated web forming portion 105, the web calendering portion 106, and the heat treatment portion ( 107), the step 502 and the step 503 are executed. Specifically, the step 502 by the laminated web forming part 105 and the heat treatment part 107 and the calendering step (step 503) by the web calender part 106 in the middle are performed.

By performing these steps 501, 502, and 503, the air-through nonwoven fabric 10 for absorbent articles of the present embodiment described above can be manufactured with high precision. That is, even when the fiber layer 8 having the fiber mass 7 is included, the air-through nonwoven fabric 10 for absorbent articles having a shape and excellent bulkiness and soft touch can be produced with good precision. The produced air-through nonwoven fabric 10 for absorbent articles is wound up in a roll shape as necessary.

In the manufacturing method of this embodiment, a calendering process (process 503) is performed with respect to the laminated web 90 before air-through processing. However, the present invention is not limited thereto, and the single-layer web 81 and the single-layer web 82 before lamination may be individually calendered, or the air-through nonwoven fabric after the air-through may be calendered. In addition, when calendering is performed on the air-through nonwoven fabric, the air-through nonwoven fabric to be processed becomes a raw material air-through nonwoven fabric before becoming the air-through nonwoven fabric 10 for absorbent articles of the present embodiment.

In the manufacturing method of the present embodiment, when the fiber mass 7 is crushed by the calender by performing the calendering process (step 503), the part other than the fiber mass 7 is also smoothed by calendering and is smooth. It gets worse. Since the nonwoven fabric 10 with a smooth surface maintains the thickness of a plurality of fiber layers and is integrated, it has a thickness and cushioning properties that reduce the feeling of foreign matter (discomfort) in contact with the skin of the fiber mass 7 do.

In addition, in the manufacturing method of this embodiment, the fiber mass can be crushed in a consistent manufacturing process of a nonwoven fabric. Therefore, it is not necessary to introduce a fiber lump inspection device after the production of the nonwoven fabric, and it is possible to reduce the manufacturing cost. Further, since the inspection treatment after production, the calender treatment and the hot air recovery treatment are not required, it is possible to realize improvement in the production efficiency of the nonwoven fabric.

From the viewpoint of effectively reducing the hardness of the fiber ingot 7, the calendering process described above is preferably a web calendering process performed on one or more selected from a single-layer web or a laminated web.

In addition, the calendering process is not limited to the case of performing only in one of the steps of a single-layer web, a step of a laminated web, and a step of an air-through nonwoven fabric, and may be performed in two or more steps. In addition, in each step, the calendering process is not limited to the case of performing once, and may be performed twice or more. For example, it is not limited to the case where calendering is performed only once on the laminated web 90 of the present embodiment, and may be performed twice 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, 82, and the air-through nonwoven fabric (raw material air-through nonwoven fabric) pinched by the calender rolls 106A and 106B, Among the linear pressures applied by all the rolls to the single-layer webs 81 and 82, the laminated webs 90 and 95, and the air-through nonwoven fabric 601 in the entire process, the highest one is preferable. All the rolls referred to herein mean all rolls used in the entire manufacturing process other than the above-described calender rolls 106A and 106B. For example, a nip roll for conveyance of a nonwoven fabric after heat treatment, a nip roll or a press roll at the time of winding up, a press roll at the time of a subsequent slit, and the like correspond.

In particular, in the calendering process, the linear pressure P applied to the single-layer webs 81 and 82 and the laminated web 90 is 20 N in terms of effectively reducing the hardness of the fiber mass 7 before heat fusion. /Cm or more is preferable, 100 N/cm or more is more preferable, and 180 N/cm or more is still more preferable. Further, the linear pressure P is preferably 700 N/cm or less, more preferably 500 N/cm or less, and still more preferably 250 N/cm or less from the viewpoint of recovery of the thickness after pressing. Specifically, the line pressure (P) is preferably 20 N/cm or more and 700 N/cm or less, more preferably 100 N/cm or more and 500 N/cm or less, and 180 N/cm or more and 250 N/cm or less Is more preferred.

The pair of calender rolls 106A and 106B used in the web calender portion 106 is a roll having a smooth circumferential surface. Various materials used for calendering can be used as the material. Moreover, the material of the calender roll 106A and the material of the calender roll 106B may be the same or different.

Among them, the calender roll used for calendering is preferably a combination of a resin roll and a rigid roll from the viewpoint of further enhancing the effect of reducing the hardness of the fiber ingot 7. In the web calendering process of the present embodiment, the calender roll 106A is one that abuts the web 82 containing the thick fibers of the laminated web 90, and is a rigid roll, and the calender roll 106B is a laminated web ( A resin roll is used as the one that contacts the web 81 containing 90) fine fibers. However, the arrangement of the resin roll and the rigid roll is not limited to this, and the opposite combination may be used.

The hardness of the resin roll is preferably 20 degrees or more, more preferably 50 degrees or more, and 80 degrees in D hardness (JIS K6253-3) from the viewpoint of further enhancing the effect of reducing the hardness of the fiber ingots 7 The above is more preferable. Further, the hardness of the resin roll is preferably 100 degrees or less, more preferably 95 degrees or less, and still more preferably 90 degrees or less in D hardness (JIS K6253-3) from the same viewpoint. Specifically, the hardness of the resin roll is preferably 20 degrees or more and 100 degrees or less, more preferably 50 degrees or more and 95 degrees or less, and even more preferably 80 degrees or more and 90 degrees or less.

In addition, it is preferable that air-through processing has a plurality of air-through processing.

3 shows an embodiment of a heat treatment unit (air through processing unit) having a first air through treatment unit 117 and a second air through treatment unit 127. In this embodiment, the air-through processing is performed twice: the first air-through treatment and the second air-through treatment. However, the number of times of air-through treatment is not limited to two times in FIG. 3, and may be three or more times. When the air-through processing has three or more air-through treatments, the "rear-end air-through treatment" to the "first air-through treatment" means the second and subsequent air-through treatments. In the two air-through treatments in Fig. 3, "the first air-through treatment" is a first air-through treatment, and the "rear-end air-through treatment" refers to a second air-through treatment. In the air through process shown in FIG. 3 (two air through treatments), hot air injection is performed in the hood 107C of the first air through treatment unit 117 (arrow F1), and the second air through treatment unit 127 is Hot air jetting is performed in the hood 107D (arrow F2). At this time, the laminated web 95 subjected to web calendering is continuously conveyed from the first air through treatment unit 117 to the second air through treatment unit 127 by the conveyor belt 107B. Thereby, the 1st air-through processing and the 2nd air-through processing are performed continuously with respect to the laminated web 95.

In the air through process, it is preferable that the air through treatment at the rear stage has a higher wind speed of the hot air than the air through treatment at the first stage, that is, the first air through treatment is performed at a low wind speed. As a result, volume reduction due to wind pressure in the air-through treatment unit is suppressed, the hot air recovery effect is expressed, and the web becomes bulky. In particular, when calendering is performed on the laminated web 90 or the single-layered webs 81 and 82 before nonwoven fabrication as in the present embodiment, the above treatment in the subsequent air-through treatment is effective.

Specifically, the wind speed S1 of the hot air in the first air-through treatment is preferably 0.2 m/sec or more, more preferably 0.25 m/sec or more, and even more preferably 0.4 m/sec or more. The wind speed S1 of hot air in the first air-through treatment is preferably 1.2 m/sec or less, more preferably 0.8 m/sec or less, and even more preferably 0.5 m/sec or less. Specifically, the wind speed (S1) is preferably 0.2 m/sec or more and 1.2 m/sec or less, more preferably 0.25 m/sec or more and 0.8 m/sec or less, and 0.4 m/sec or more and 0.5 m/sec or less Is more preferred. Thereby, the crushing of the web is suppressed, and the effect of restoring the thickness is expressed.

The wind speed (S2) of the hot air in the air-through treatment at the rear stage is preferably 0.8 m/sec or more, more preferably 0.9 m/sec or more, and even more preferably 1.2 m/sec or more. The wind speed (S2) of the hot air in the air-through treatment at the rear stage is preferably 1.6 m/sec or less, more preferably 1.4 m/sec or less, and still more preferably 1.3 m/sec or less. Specifically, the wind speed S2 is preferably 0.8 m/sec or more and 1.6 m/sec or less, more preferably 0.9 m/sec or more and 1.4 m/sec or less, and 1.2 m/sec or more and 1.3 m/sec or less Is more preferred. As a result, air evenly penetrates the web, and heat energy is effectively imparted to the web, resulting in a nonwoven fabric structure.

The difference (S3) (= S2-S1) between the wind speed (S1) of hot air in the first air-through treatment and the wind speed (S2) of hot air in the air through treatment at the subsequent stage is preferably more than 0 m/sec, , 0.4 m/sec or more is more preferable, and 0.8 m/sec or more is still more preferable. The difference (S3) (= S2-S1) between the wind speed (S1) of hot air in the first air-through treatment and the wind speed (S2) of hot air in the air-through treatment at the subsequent stage is preferably 1.4 m/sec or less. , 1.2 m/sec or less is more preferable, and 1 m/sec or less is still more preferable. The difference (S3) (= S2-S1) between the wind speed (S1) of hot air in the first air-through treatment and the wind speed (S2) of hot air in the air through treatment at the subsequent stage is specifically, 0 m/sec Exceeding 1.4 m/sec or less is preferable, 0.4 m/sec or more and 1.2 m/sec or less are more preferable, and 0.8 m/sec or more and 1 m/sec or less are still more preferable. Thereby, it is possible to effectively realize both volume recovery and nonwoven fabrication.

Further, in the air through process, it is preferable that the air through treatment at the rear stage has a higher temperature of the hot air than the air through treatment at the first stage. Thereby, the fusion of the fibers proceeds in stages, so that the recovery of the web in the air-through treatment portion is effectively expressed. In particular, when calendering is performed on the laminated web 90 or the single-layered webs 81 and 82 before nonwoven fabrication as in the present embodiment, the above-described effect in the subsequent air-through treatment is higher.

Specifically, the temperature (P1) of the hot air in the first air-through treatment is preferably 85°C or higher, more preferably 90°C or higher, and still more preferably 100°C or higher. The temperature (P1) of hot air in the first air-through treatment is preferably 134°C or less, more preferably 115°C or less, and even more preferably 105°C or less. Specifically, the temperature (P1) of hot air in the first air-through treatment is preferably 85°C or more and 134°C or less, more preferably 90°C or more and 115°C or less, and even more preferably 100°C or more and 105°C or less. Do. Thereby, the recovery property of the web in the air-through treatment unit can be effectively expressed.

The temperature (P2) of the hot air in the air-through treatment at the rear stage is not less than the melting point of the component of the fiber surface to be used (for example, the sheath part in the core-sheath type conjugate fiber), and is preferably 145° C. or less, and 137° C. The following is more preferable, and 134 degreeC or less is still more preferable. Specifically, the temperature (P2) of the hot air in the air-through treatment at 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°C, and more than the melting point of the component on the surface of the fiber to be 137°C or less. It is preferable, and the melting point of the component of the fiber surface to be used is more preferably 134°C or less. Thereby, it is possible to realize the manufacture of a nonwoven fabric having a good texture.

The difference (P3) (=P2-P1) between the temperature of the hot air in the first air-through treatment (P1) and the temperature of the hot air in the air-through treatment in the subsequent stage (P2) is preferably greater than 0°C, and 20 More preferably, at least 30°C is more preferable. The difference (P3) (=P2-P1) between the temperature of the hot air in the first air-through treatment (P1) and the temperature of the hot air in the air-through treatment in the subsequent stage (P2) is preferably 60°C or less, and 40 It is more preferable that it is lower than a degreeC, and 35 degreeC or less is still more preferable. The difference (P3) (= P2-P1) between the temperature of the hot air in the first air-through treatment (P1) and the temperature of the hot air in the air through treatment in the subsequent stage (P2) is, specifically, more than 0°C 60 It is preferably at least 20°C, more preferably at least 20°C and at most 40°C, and still more preferably at least 30°C and at most 35°C. Thereby, it is possible to realize the production of a nonwoven fabric having a large volume and good texture.

In addition, in the manufacturing method of the air-through nonwoven fabric for absorbent articles of the present embodiment, as shown below, it is preferable to once recover unnecessary portions such as scraps generated in the manufacturing process and return to the opening step again (step 504). .

In this step 504, a step of recovering the end of the web in the width direction in the card machine used in the opening step, and a step of partially recovering the air-through nonwoven fabric and cutting and opening the portion of the recovered air-through nonwoven fabric. It has one or both sides. The recovered web and portions of the air-through nonwoven fabric cut and opened are provided to the opening step. In addition, the part of the air-through nonwoven fabric which is cut and opened is not limited to this, including, but is not limited to, a scrapped part at an end portion in the width direction, and refers to a processing condition adjusted product or an out-of-standard product generated in the nonwoven fabric manufacturing process.

In Fig. 2, a specific example of the step 504 is shown. For the single-layer webs 81 and 82 formed in the card machine of the carding portions 103 and 104, the ends (not shown) in the width direction are sucked and recovered (arrows 181 and 182). Further, the air-through nonwoven fabric 10 obtained by performing the air-through processing in the heat treatment unit 107 is partially recovered (arrow 183). In this case, since the portion of the recovered air-through nonwoven fabric cannot be reused as it is, it is cut by the cutting/opening unit 108 and opened to return to a fibrous shape.

The recovered web and the portion of the air-through nonwoven fabric cut and opened are returned to the opening portion 101, and are opened again to be used as a material for forming a web (arrow 184). At this time, it is possible to return to either the opening portion 101 and the opening portion 102. 2 is shown as returning to the opening portion 101. In the case of returning to the opening portion 101, the ratio of the fine fibers in the formed web 81 is maintained at a constant or higher, and the content of the coarse fibers is suppressed to within several% (for example, within 5%). , It is preferable to appropriately prepare the input amount of the new raw fiber (fine fiber) 71. Thereby, while forming the fiber mass 7 in the web 81, a large number of fine fibers are contained, and the soft touch on the side 10A side of the nonwoven fabric 10 can be realized.

Moreover, the return of the said material is not limited to the aspect shown in FIG. For example, the material recovered from the carding portion 103 may be returned to the opening portion 101, and the material recovered from the carding portion 104 may be returned to the opening portion 102. In that case, it is preferable that the portion of the air-through nonwoven fabric cut and opened is returned to the opening portion 102.

As described above, according to the manufacturing method of the present embodiment, the nonwoven fabric 10 having a shape excellent in bulkiness and a soft touch can be preferably manufactured. In particular, the thickness (T1, T2) and the difference (T3) (= T1-T2) under the pressure of 7.64 kPa described above, and the average coefficient of friction (Q1, Q2) and the difference (Q3) (= Q1-Q2) A nonwoven fabric 10 having the physical properties shown by) can be preferably manufactured. In addition, the shape of the fiber mass 7, in particular, the shape of the fiber mass 7 having a flattened thickness makes the nonwoven fabric 10 aesthetically pleasing.

The obtained air-through nonwoven fabric for an absorbent article of the present invention is inserted as a predetermined constituent member in the absorbent article in accordance with the purpose in the manufacturing process of the absorbent article (insertion step). It is preferable that the insertion process is, for example, the following process. That is, the obtained air-through nonwoven fabric for an absorbent article of the present invention is prepared by cutting into a size or shape according to the purpose, and placed in a predetermined position with respect to other constituent members. Subsequently, rotation and folding are performed together with other members as necessary, and they are joined and inserted into the absorbent article. Thus, in the manufacturing process of an absorbent article, the target absorbent article is manufactured through the process of inserting the air-through nonwoven fabric for absorbent articles of the present invention.

Among them, the air-through nonwoven fabric for an absorbent article of the present invention realizes both bulkiness and a soft touch, and has a shape that can be visually appealed to the user. It is preferable that it is a process of inserting into the member of the outermost layer on the skin surface side (for example, a top sheet or a side sheet). In particular, it is preferable that it is a step of inserting into the absorbent article as a surface sheet that contacts the skin and is most prominent. In that case, it is preferable that the air-through nonwoven fabric for an absorbent article of the present invention has a configuration in which a fibrous layer having a fiber lump portion is used as the outermost layer of the nonwoven fabric. It is more preferable that the air-through nonwoven fabric for an absorbent article of the present invention is disposed on the outermost layer on the skin side of the absorbent article, and the fibrous layer having the fiber mass portion is disposed toward the skin side of the absorbent article.

Regarding the above-described embodiments, the present invention further discloses the following air-through nonwoven fabric for absorbent articles and a method of manufacturing the air-through nonwoven fabric for absorbent articles.

<1>

An air-through nonwoven fabric in which two or more fibrous layers are laminated, comprising a thermoplastic fiber and having at least one fibrous layer having a fiber mass portion.

<2>

The air-through nonwoven fabric for absorbent articles includes fine fibers having a fiber diameter of 1 dtex or more and 2.2 dtex or less, preferably 1 dtex or more, more preferably 1.2 dtex or more, preferably 2 dtex or less, and more preferably 1.5 dtex or less. , Has a thicker fiber with a larger fiber diameter than the finer fiber,

The air-through nonwoven fabric for an absorbent article according to <1>, wherein the fibrous layer having the fibrous mass contains the fine fibers.

<3>

The air-through nonwoven fabric for absorbent articles described in <2>, wherein the content of the fine fibers in the fiber layer having the fiber mass 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 absorbent articles according to any one of the above <1> to <3>, which has at least one fiber layer having no fiber mass portion.

<5>

The air-through nonwoven fabric for absorbent articles has a fiber diameter of more than 2.2 dtex and 7 dtex or less, preferably more than 2.2 dtex, more preferably 4.4 dtex or more, preferably 5.5 dtex or less, and more preferably 5 dtex or less. , It has a finer fiber with a diameter smaller than that of the thick fiber,

The air-through nonwoven fabric for absorbent articles according to <4>, wherein the fibrous layer having no fibrous mass contains the coarse fibers.

<6>

The air through for absorbent articles according to the above <5>, wherein the content of the coarse fibers in the fiber layer having no fiber mass is 50% by mass or more, preferably 80% by mass or more, and more preferably 100% by mass. Non-woven.

<7>

The absorbent article according to <5> or <6>, wherein the content of the coarse fibers in the layer having the fiber mass is 50% by mass or less, preferably 30% by mass or less, and more preferably 10% by mass or less. For air-through non-woven fabric.

<8>

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

<9>

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

<10>

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

<11>

The difference between the basis weight of the fiber layer not having the fiber mass and the basis weight of the fiber layer having the fiber mass is greater than 0 g/m 2 and not more than 20 g/m 2, preferably 3 g/m 2 or more, more preferably 5 g/m 2 The air-through nonwoven fabric for absorbent articles according to the above <10>, wherein the air-through nonwoven fabric according to <10> is above, preferably 15 g/m 2 or less, more preferably 10 g/m 2 or less.

<12>

The basis weight of the entire air-through nonwoven fabric for absorbent articles is 15 g/m 2 or more and 40 g/m 2 or less, preferably 18 g/m 2 or more, more preferably 20 g/m 2 or more, preferably 30 g/m 2 Hereinafter, the air-through nonwoven fabric for absorbent articles according to any one of the above <1> to <11>, which is more preferably 25 g/m 2 or less.

<13>

The absorbent article measured under the same pressure at the position where the fiber ingots are disposed and the thickness of the air-through nonwoven fabric for absorbent articles measured under a pressure of 7.64 kPa is T1, and in the location where the fiber ingots are not disposed When the thickness of the air-through nonwoven fabric for use is set to T2, the difference in thickness (T3) defined by T3 = T1-T2 is 0.4 mm or less, preferably 0.3 mm or less, more preferably 0.2 mm or less, and more preferably The air-through nonwoven fabric for absorbent articles according to any one of the above <1> to <12>, which is preferably 0 (zero) mm.

<14>

<1, wherein the average coefficient of friction of the air-through nonwoven fabric for absorbent articles at the position where the fiber mass is disposed 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. The air-through nonwoven fabric for absorbent articles according to any one of> to <13>.

<15>

The difference between the average coefficient of friction of the air-through nonwoven fabric for absorbent articles at the position where the fiber lumps are disposed and the average friction coefficient at the position where the fiber lumps are not disposed is 0.7 or less, preferably 0.5 or less, more The air-through nonwoven fabric for an absorbent article according to the above <14>, which is preferably 0.32 or less, more preferably 0.3 or less, and particularly preferably 0 (zero).

<16>

Any one of the above <1> to <15>, wherein the fiber mass has a flat shape crushed in the thickness direction of the nonwoven fabric in the cross section in the thickness direction of the nonwoven fabric, and has a smooth structure on the surface of the fiber mass on the nonwoven fabric surface side. The air-through nonwoven fabric for absorbent articles described in.

<17>

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

<18>

An absorbent article comprising the air-through nonwoven fabric for absorbent articles according to any one of the above <1> to <17>.

<19>

An absorbent article in which the air-through nonwoven fabric for absorbent articles according to the above <17> is disposed on the outermost layer of the absorbent article on the skin surface side, and the fibrous layer having the fiber mass is disposed toward the skin surface side.

<20>

The absorbent article according to the above <18> or <19>, comprising the air-through nonwoven fabric for absorbent articles as a top sheet.

<21>

An opening process of forming a web by subjecting the thermoplastic fiber to the opening treatment multiple times, and

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

A method of manufacturing an air-through nonwoven fabric for an absorbent article having a calendering process performed using a pair of calender rolls for one or more selected from the single-layer web, the laminated web, and the air-through nonwoven fabric.

<22>

In the entire process of the manufacturing method of the air-through nonwoven fabric for absorbent articles,

The method for producing an air-through nonwoven fabric for an absorbent article according to the above <21>, wherein the line pressure in the calendering step is the highest among the line pressures applied to the single-layer web, the laminated web, and the air-through nonwoven fabric.

<23>

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

<24>

In the web calendering process, the line pressure applied to the single-layer web or the laminated web is 20 N/cm or more and 700 N/cm or less, preferably 100 N/cm or more, more preferably 180 N/cm or more, preferably Preferably it is 500 N/cm or less, More preferably, it is 250 N/cm or less, The manufacturing method of the air-through nonwoven fabric for absorbent articles according to the above <23>.

<25>

The method for producing an air-through nonwoven fabric for absorbent articles according to any one of <21> to <24>, wherein the pair of calender rolls used in the calendering step is a combination of a resin roll and a rigid roll.

<26>

The hardness of the resin roll is 20 degrees or more and 100 degrees or less in D hardness, preferably 50 degrees or more, more preferably 80 degrees or more, preferably 95 degrees or less, more preferably 90 degrees or less, the < The method for producing the air-through nonwoven fabric for absorbent articles according to <25>.

<27>

The air-through for an absorbent article according to any one of the above <21> to <26>, wherein the air-through processing has a plurality of air-through treatments, and the air-through treatment at a later stage is faster than the first air-through treatment. Method of making a nonwoven fabric.

<28>

The wind speed of the hot air in the first air-through treatment is 0.2 m/sec or more and 1.2 m/sec or less, preferably 0.25 m/sec or more, more preferably 0.4 m/sec or more, preferably 0.8 m/sec. sec or less, more preferably 0.5 m/sec or less, the method for producing an air-through nonwoven fabric for absorbent articles according to the above <27>.

<29>

The wind speed of hot air in the air-through treatment at the rear stage is 0.8 m/sec or more and 1.6 m/sec or less, preferably 0.9 m/sec or more, more preferably 1.2 m/sec or more, preferably 1.4 m/sec. sec or less, more preferably 1.3 m/sec or less, the method for producing an air-through nonwoven fabric for absorbent articles according to the above <27> or <28>.

<30>

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

<31>

The air-through for an absorbent article according to any one of the above <21> to <30>, wherein the air-through processing has a plurality of air-through treatments, and the air-through treatment at a later stage than the first air-through treatment has a higher temperature of hot air. Method of making a nonwoven fabric.

<32>

The temperature of the hot air in the first air-through treatment is 85°C or more and 134°C or less, preferably 90°C or more, more preferably 100°C or more, preferably 115°C or less, and more preferably 105°C or less. , The method for producing the air-through nonwoven fabric for absorbent articles according to the above <31>.

<33>

The temperature of the hot air in the air-through treatment at the later stage is not less than the melting point of the component on the surface of the fiber to be used and not more than 145°C, preferably not less than the melting point of the component on the surface of the fiber to be used, preferably not more than 137°C, more preferably The method for producing an air-through nonwoven fabric for absorbent articles according to the above <31> or <32>, preferably 134°C or less.

<34>

The difference between the temperature of the hot air in the first air-through treatment and the temperature of the hot air in the air-through treatment at the subsequent stage is more than 0°C and not more than 60°C, preferably 20°C or more, more preferably 30°C or more, preferably The method for producing an air-through nonwoven fabric for absorbent articles according to any one of the above <31> to <33>, preferably 40°C or less, more preferably 35°C or less.

<35>

One or both of the processes of recovering the width direction end of the web in the card machine used in the opening process, and the process of partially recovering the air-through nonwoven fabric and cutting and opening the recovered air-through nonwoven fabric. Have,

The method for producing an air-through nonwoven fabric for an absorbent article according to any one of the above <21> to <34>, wherein the recovered web and the portion of the air-through nonwoven fabric cut and opened are provided to the opening step.

<36>

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

<37>

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

<38>

An absorbent article manufacturing method comprising a step of inserting the air-through nonwoven fabric for absorbent articles produced by the manufacturing method according to any one of the above <21> to <37> into the absorbent article.

<39>

The method for producing an absorbent article according to <38>, comprising a step of inserting the air-through nonwoven fabric for absorbent articles into an absorbent article as a top sheet.

Example

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not construed as being limited thereto. "←" in the following table means the same as the description on the left side.

(Example 1)

Using the manufacturing apparatus shown in FIG. 2, the nonwoven fabric sample of Example 1 was manufactured as shown below at a processing speed of 10 m/min.

First, as the raw material fibers (fine fibers) 71 forming the fibrous layer 1, a core-sheath type (core polyethylene terephthalate resin, ultra-polyethylene resin) thermoplastic fiber having a fiber diameter of 1.4 dtex was used. Using this raw material fiber 71, a plurality of opening treatments were performed in the opening portion 101 and the carding portion 103 to produce a single-layer web 81 having a basis weight of 10 g/m 2.

Moreover, as the raw material fibers (coarse fibers) 72 forming the fibrous layer 2, a core-sheath type (core polyethylene terephthalate resin, ultra-polyethylene resin) thermoplastic fiber having a fiber diameter of 4.4 dtex was used. Using this raw material fiber 72, a plurality of opening treatments were performed in the opening portion 102 and the carding portion 104 to produce a single-layer web 82 having a basis weight of 15 g/m 2.

Next, in the laminated web forming part 105, the single-layered web 82 was laminated on the single-layered web 81 to form the laminated web 90. In the web calender part 106, web calendering was performed on the laminated web 90. In the web calender part 106, the rigid calender roll 106A on the upper layer side and the calender roll 106B on the lower layer side (D hardness: 90 degrees) were used, and the line pressure was set to 200 N/cm.

With respect to the laminated web 95 subjected to web calendering, in the heat treatment unit 107, air through processing was performed in which air through treatments shown in FIG. 3 were performed twice. The wind speed and temperature of the first air through treatment and the second air through treatment were shown in Table 1. Thereby, the nonwoven fabric sample of Example 1 was produced.

In addition, in the above manufacturing method, the width direction end of the formed web or part of the nonwoven fabric was not recovered and returned to the opening step. Therefore, the fiber diameter of the raw material fiber (fine fiber) 71 became the average fiber diameter of the fiber layer 1, and the fiber diameter of the raw material fiber (coarse fiber) 72 became the average fiber diameter of the fiber layer 2.

(Examples 2 to 7)

The nonwoven fabric samples of Examples 2 to 7 were prepared in the same manner as in Example 1, except that the temperature and wind speed of the first air-through treatment were as shown in Table 1.

(Example 8)

A nonwoven fabric sample of Example 8 was prepared in the same manner as in Example 1, except that the nonwoven fabric after the air-through processing was not subjected to web calendering, except that the nonwoven fabric calendering shown in Table 1 was performed.

(Example 9)

In the same manner as in Example 1, except that the fiber diameter of the raw material fibers (fine fibers) forming the fibrous layer 1 was set to 2.0 dtex, and the temperature and wind speed of the first air-through treatment were as shown in Table 1, A sample of the nonwoven fabric of Example 9 was prepared.

(Example 10)

A nonwoven fabric sample of Example 10 was prepared in the same manner as in Example 9 except that the fiber diameter of the raw material fibers 72 forming the fibrous layer 2 was set to 2.0 dtex.

(Example 11)

In the same manner as in Example 10, except that the fiber diameter of the raw fiber (fine fiber) forming the fiber layer 1 and the fiber diameter of the raw fiber 71 forming the fiber layer 2 (lower layer) were 1.4 dtex. , A nonwoven fabric sample of Example 11 was prepared.

(Example 12)

A nonwoven fabric sample of Example 12 was produced in the same manner as in Example 11, except that the temperature and wind speed of the first air-through treatment were as 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 nonwoven fabric after air through processing was not subjected to web calendering, except that the nonwoven fabric calendering shown in Table 2 was performed.

(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 fibers 71 forming the fiber layer 2 (lower layer) was set to 1.4 dtex.

(exam)

[1] bulkiness

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

As a laser type thickness meter, it measured using the laser sensor (model number ZS-LD80) and a controller (model number ZS-LDC11) manufactured by Omron Corporation.

At the time of thickness measurement, a weight (0.05 kpa) was placed between the distal end of the laser sensor and the nonwoven fabric sample to be measured, and the thickness in such a pressed state was measured. The measurement was performed at 5 points or more, respectively, and it was set as these average values. In addition, 0.05 kPa is the load which assumed the apparent thickness of the nonwoven fabric so as not to crush the thickness as much as possible.

(2) Thickness of nonwoven fabric sample under pressure of 7.64 kPa

Based on the method described above (Measurement method of the thickness of the nonwoven fabric under a pressure of 7.64 kPa), the thickness of each nonwoven fabric sample at the location where the fiber mass is disposed (T1), the thickness at the location where the fiber mass is not disposed ( T2) was measured respectively. Further, the difference in thickness (T3 = T1-T2) was calculated.

[2] friction

Based on the method described in the above-described (Measurement Method of Average Friction Coefficient), the MIU value (Q1) at the position where the fiber lump portion of each nonwoven fabric sample is disposed, and the MIU value at the position where the fiber lump portion is not arranged ( Q2) was measured respectively. Further, the difference (Q3) (= Q1-Q2) of the MIU values was calculated.

[3] shape

For each nonwoven fabric sample, the presence or absence of a fibrous mass was visually confirmed.

As shown in Tables 1 and 2, in Examples 1 to 13, compared to Comparative Examples 1 and 2, the thickness (T1) at the position where the fiber mass was disposed under pressure of 7.64 kPa and the location where the fiber mass was not disposed. The difference (T3) of the thickness (T2) of is small, and the bulkiness in the whole nonwoven fabric is excellent. In particular, among the Examples, the nonwoven fabric subjected to heat treatment after web calendering was thicker than the calendered one after the nonwoven fabric, and a nonwoven fabric having a good texture of the fiber mass was formed.

In addition, in Examples 1 to 13, compared to Comparative Examples 1 and 2, while the shape of the fiber mass was confirmed, the average coefficient of friction (Q1) at the position where the fiber mass was disposed, and at the location where the fiber mass was not disposed. Both the average coefficient of friction (Q2) and the difference (Q3) between them were small, and the soft touch of the entire nonwoven fabric was realized.

As described above, Examples 1 to 13 had excellent bulkiness and soft touch, provided a pattern, and had excellent aesthetics.

Although the present invention has been described with its embodiments and examples, we are not intended to limit our invention in any detail of the description unless otherwise specified, and the spirit of the invention shown in the appended claims. I think it should be interpreted widely without going against the scope.

1 fiber layer
2 fiber layer
7 Fibrous mass
8 Fiber ingot layer (layer having fiber ingots)
9 Non-fibrous mass layer (layer without fibrous mass)
10 Air-through non-woven fabric for absorbent articles
100 Apparatus for manufacturing air-through nonwoven fabric for absorbent articles
101, 102 open fiber
103, 104 carding department
105 Laminated web formation
106 web calender
106A, 106B calender roll
107 Heat treatment part (air-through processing part)
117 1st air-through treatment unit
127 2nd air-through treatment unit
108 Foundation and opening department
71, 72 raw fiber
81, 82 single layer web (or web)
90 laminated web
95 web calendered laminated web

Claims (39)

An air-through nonwoven fabric for absorbent articles in which two or more layers of fibrous layers are laminated,
An air-through nonwoven fabric for an absorbent article, comprising at least one fiber layer comprising a thermoplastic fiber and having a fiber mass portion formed of the thermoplastic fiber. The method of claim 1,
An air-through nonwoven fabric for an absorbent article in which the fiber mass and the fiber are thermally fused. An air-through nonwoven fabric for absorbent articles in which two or more layers of fibrous layers are laminated,
At least one fiber layer comprising a thermoplastic fiber and having a fiber mass portion,
The absorbent article measured under the same pressure at the position where the fiber ingots are disposed and the thickness of the air-through nonwoven fabric for absorbent articles measured under a pressure of 7.64 kPa is T1, and in the location where the fiber ingots are not disposed When the thickness of the air-through nonwoven fabric for use is T2, the difference in thickness (T3) defined by T3 = T1-T2 is 0.3 mm or less. An air-through nonwoven fabric for absorbent articles in which two or more layers of fibrous layers are laminated,
At least one fiber layer comprising a thermoplastic fiber and having a fiber mass portion,
The air-through nonwoven fabric for an absorbent article, wherein the fibrous layer having the fiber mass is an outermost layer of the air-through nonwoven fabric for an absorbent article, and the air-through nonwoven fabric for an absorbent article is disposed on the outermost layer on the skin surface side of the absorbent article. The method according to any one of claims 1 to 4,
The air-through nonwoven fabric for absorbent articles has fine fibers having a fiber diameter of 1 dtex or more and 2.2 dtex or less, or 1 dtex or more and 2 dtex or less, or 1.2 dtex or more and 1.5 dtex or less, and thick fibers having a larger fiber diameter than the fine fibers,
The air-through nonwoven fabric for absorbent articles, wherein the fibrous layer having the fibrous mass includes the fine fibers. The method of claim 5,
The air-through nonwoven fabric for absorbent articles, wherein the content of the fine fibers in the fiber layer having the fiber mass is 50% by mass or more, 80% by mass or more, or 100% by mass. The method according to any one of claims 1 to 4,
Having at least one fibrous layer not having the fibrous mass,
An air-through nonwoven fabric for an absorbent article, wherein the basis weight of the fibrous layer not having the fibrous mass is larger than the fibrous layer having the fibrous mass. The method of claim 7,
The difference between the basis weight of the fiber layer not having the fiber mass and the basis weight of the fiber layer having the fiber mass is greater than 0 g/m2 and not more than 20 g/m2, or more than 3 g/m2 and less than 15 g/m2, or more than 5 g/m2 An air-through nonwoven fabric for absorbent articles that is 10 g/m 2 or less. The method according to any one of claims 1 to 4,
The air-through nonwoven fabric for an absorbent article, wherein an average coefficient of friction of the air-through nonwoven fabric for an absorbent article at a position where the fiber mass is disposed is 1.6 or more and 2.5 or less, or 1.6 or more and 2.4 or less, or 1.6 or more and 2.3 or less. The method of claim 9,
The difference between the average coefficient of friction of the air-through nonwoven fabric for absorbent articles at a position where the fiber mass is disposed and the average coefficient of friction at a position where the fiber mass is not disposed is 0.7 or less, or 0.5 or less, or 0.32 or less, Or 0.3 or less, or 0 (zero) phosphorus, an air-through nonwoven fabric for absorbent articles. An absorbent article comprising the air-through nonwoven fabric for absorbent articles according to any one of claims 1 to 4. An opening process of forming a web by subjecting the thermoplastic fiber to the opening treatment multiple times, and
A step of laminating a plurality of single-layer webs obtained in the opening step to form a laminated web, and subjecting the laminated web to air-through processing by hot air to obtain an air-through nonwoven fabric;
A method for producing an air-through nonwoven fabric for absorbent articles, comprising a web calendering step performed on one or more selected from the single-layer web and the laminated web. An opening process of forming a web by subjecting the thermoplastic fiber to the opening treatment multiple times, and
A step of laminating a plurality of single-layer webs obtained in the opening step to form a laminated web, and subjecting the laminated web to air-through processing by hot air to obtain an air-through nonwoven fabric;
It has a calendering process performed using a pair of calender rolls for one or more selected from the single-layer web, the laminated web, and the air-through nonwoven fabric,
The method of manufacturing an air-through nonwoven fabric for an absorbent article, wherein the air-through processing has a plurality of air-through treatments. The method of claim 12 or 13,
The method of manufacturing an air-through nonwoven fabric for an absorbent article, wherein the air-through processing has a plurality of air-through treatments, and the air-through treatment at a later stage is faster than the first air-through treatment. The method of claim 12 or 13,
The method of manufacturing an air-through nonwoven fabric for an absorbent article, wherein the air-through processing has a plurality of air-through treatments, and the air-through treatment at a later stage has a higher temperature of hot air than the first air-through treatment. The method of claim 12 or 13,
One or both of the processes of recovering the width direction end of the web in the card machine used in the opening process, and the process of partially recovering the air-through nonwoven fabric and cutting and opening the recovered air-through nonwoven fabric. Have,
A method of manufacturing an air-through nonwoven fabric for an absorbent article, wherein the recovered web and a portion of the air-through nonwoven fabric cut and opened are provided to the opening step. The method of claim 12 or 13,
The method of manufacturing an air-through nonwoven fabric for an absorbent article, wherein the laminated web has a plurality of types of fibers having different fiber diameters. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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