WO2021172476A1 - Nonwoven fabric, nonwoven fabric product and absorbent article each provided with same, and method for producing said nonwoven fabric product - Google Patents

Abstract

The present invention is a nonwoven fabric which has a first surface and a second surface. The nonwoven fabric contains thermoplastic fibers, while having, as a thermally fused part (P) where intersection points of the fibers are thermally fused to each other, a generally orthogonal fused part (C) where fibers are thermally fused to each other, while being intersect with each other at an angle of from 70° to 90°. The nonwoven fabric contains fine fibers that have a fiber diameter of 15 μm or less. If an observation area of 500 μm × 400 μm in at least one surface of the nonwoven fabric is observed at a magnification of 200 times, the fine fiber ratio of 20% or more, and the generally orthogonal fused part ratio, which is the ratio of the number of the generally orthogonal fused parts (C) to the number of the thermally fused parts (P) in the observation area, is 35% or more.

Description

Non-woven fabric, a non-woven fabric product and an absorbent article provided with the non-woven fabric, and a method for manufacturing the non-woven fabric product.

The present invention relates to a non-woven fabric, a non-woven fabric product and an absorbent article provided with the non-woven fabric, and a method for manufacturing the non-woven fabric product.

Nonwoven fabric is used for the sheet members that make up absorbent articles such as disposable diapers. As such a non-woven fabric, there is known a non-woven fabric made of heat-sealing fibers, in which these fibers are fused to each other at their intersections. For example, the applicant has previously made a non-woven fabric composed of at least two types of heat-fusing fibers that are mixed and difficult to fuse with each other, and a portion in which fibers of the same type are fused to each other is present throughout. It has been proposed (Patent Document 1).

In addition, the applicant has previously included a heat-sealing composite fiber composed of a first resin component and a second resin component having a higher melting point than the first resin component, and the fiber fusion section in which the portions where these fibers are in contact with each other are fused. Is formed, and the number of portions where the heat-sealing composite fibers are fixed in parallel on one surface is a predetermined ratio with respect to the number of the fiber-sealing portions. (Patent Document 2).

Further, the applicant has previously laminated the first fiber layer and the second fiber layer made of the non-woven fabric, and the first fiber layer protrudes in the direction away from the second fiber layer to form a large number of hollow convex portions. The first fiber and the second fiber contained in the first fiber layer contain a high melting point component and a low melting point component, respectively, and the diameter ratio between the high melting point component and the low melting point component is different. (Patent Document 3).

A composite non-woven fabric having at least two layers in which a short fiber non-woven fabric (A) having a fiber length of 38 to 90 mm and a short fiber non-woven fabric (B) having a fiber length of 3 to 30 mm are bonded, and the short fiber non-woven fabric (B) is at least. It is a heat-sealing composite short fiber composed of a heat-sealing resin of two kinds of high melting point components and a low melting point component, and the heat-sealing composite single fibers are heat-sealed and formed. Patent Document 4 describes a composite nonwoven fabric characterized in that the intersection angle distribution of short fiber contacts occupies at least 50% of the total number of contacts of the short fiber nonwoven fabric (B) at an intersection angle of 60 to 90 °. ..
It is a composite fiber of at least two layers in which a long fiber non-woven fabric and a short fiber non-woven fabric are bonded, which is used for an absorbent article or the like, and the short fiber non-woven fabric is thermoplastic of at least two kinds of high melting point components and low melting point components. It is a heat-sealing composite short fiber made of a resin, and the heat-sealing composite short fibers are heat-sealed to each other, and the crossing angle distribution of the short fiber contacts formed is a percentage of the crossing angle of 60 to 90 ° ( %) Is a predetermined value with respect to the total number of contacts of the short fiber nonwoven fabric, and the composite nonwoven fabrics are described in Patent Documents 5 and 6, respectively.
It has a unidirectionally arranged nonwoven fabric in which filaments spun from a thermoplastic resin are arranged in one direction, or a laminated nonwoven fabric in which two said unidirectionally arranged nonwoven fabrics are laminated so that the arrangement directions of the filaments are orthogonal to each other. Patent Document 7 describes a non-woven fabric having a filament diameter of 3 to 20 μm, a bulk density of 0.1 g / cm ³ or more, and a texture of 5 to 40 g / cm ^2.

Japanese Unexamined Patent Publication No. 09-279467 International Publication No. 2011/046065 Japanese Unexamined Patent Publication No. 2017-024411 Japanese Unexamined Patent Publication No. 10-273884 Japanese Unexamined Patent Publication No. 09-021055 Japanese Unexamined Patent Publication No. 09-117470 Japanese Unexamined Patent Publication No. 2006-043998

The present invention is a non-woven fabric having a first surface and a second surface located on the opposite side of the first surface.
The non-woven fabric contains thermoplastic fibers, and is a substantially orthogonal type in which the fibers are heat-sealed in a state where the fibers intersect at an angle of 70 ° or more and 90 ° or less as a heat-sealing portion where the intersections of the fibers are heat-sealed. It is preferable to have a fused portion.
The non-woven fabric preferably contains fine fibers having a fiber diameter of 15 μm or less.
At least one of the first surface and the second surface of the non-woven fabric has a fine fiber ratio of 20% or more when the observation region of 500 μm × 400 μm is observed at a magnification of 200 times, and is within the observation region. It is preferable that the ratio of the substantially orthogonal fused portions, which is the ratio of the number of the substantially orthogonal fused portions to the number of existing heat fused portions, is 35% or more.

Further, the present invention is a non-woven fabric product including the non-woven fabric.
It is preferable that the first surface has a higher ratio of the substantially orthogonal fused portion than the second surface.
It is preferable that the first surface of the nonwoven fabric product is arranged so as to form the surface of the nonwoven fabric product.

Further, the present invention is an absorbent article including the non-woven fabric as a constituent member.

Further, the present invention is a method for manufacturing a nonwoven fabric product, comprising a nonwoven fabric having a first surface and a second surface located on the opposite side of the first surface.
The non-woven fabric contains thermoplastic fibers and has a substantially orthogonal fusion portion in which the fibers are fused in an orthogonal state as a heat fusion portion in which the intersections of the fibers are heat-sealed. preferable.
The non-woven fabric preferably contains fine fibers having a fiber diameter of 15 μm or less.
At least one of the first surface and the second surface of the non-woven fabric has a fine fiber ratio of 20% or more when the observation region of 500 μm × 400 μm is observed at a magnification of 200 times, and is within the observation region. It is preferable that the ratio of the substantially orthogonal fused portions, which is the ratio of the number of the substantially orthogonal fused portions to the number of existing heat fused portions, is 35% or more.
It is preferable that the method for producing the non-woven fabric product includes a step of superimposing the non-woven fabric on the non-woven fabric so that the surface having the substantially orthogonal fused portion ratio is facing the other constituent members.
Other features of the invention will become apparent from the claims and the description below.

FIG. 1 is an example of an observation image in which one surface of the non-woven fabric of the present invention is observed using a scanning electron microscope. FIG. 2 is a schematic view showing an embodiment of a substantially orthogonal fused portion according to the present invention. FIG. 3 is a view corresponding to FIG. 2 of a non-woven fabric having a parallel type fused portion.

Detailed description of the invention

Using fibers with a small fiber diameter for the non-woven fabric is effective in that it can improve the texture and smoothness when touched by hand. However, such a non-woven fabric tends to have high extensibility, and in the stretched state, the width of the non-woven fabric may shrink, resulting in width shrinkage. In particular, in the production of a non-woven fabric product using this non-woven fabric, if tension is applied to the non-woven fabric during transportation and the width shrinks, the width as designed may not be obtained and defective products may occur. Patent Documents 1 to 7 do not disclose a technique for suppressing width shrinkage of a non-woven fabric.

Therefore, an object of the present invention is to provide a non-woven fabric in which width shrinkage is suppressed while containing fibers having a small fiber diameter, a non-woven fabric product and an absorbent article provided with the non-woven fabric, and a method for producing the non-woven fabric product.

Hereinafter, the present invention will be described based on the preferred embodiment with reference to the drawings.
The non-woven fabric of the present embodiment contains thermoplastic fibers, and has a heat-sealed portion P in which the intersections of the fibers are heat-sealed. Such a heat-sealing portion P is formed at a portion where the thermoplastic fibers are in contact with each other, and is three-dimensionally dispersed and arranged in the non-woven fabric.
The non-woven fabric of the present embodiment has a substantially orthogonal fusion portion C as the heat fusion portion P. The substantially orthogonal fusion portion C is a portion where the fibers are fused in a substantially orthogonal state at the intersection of the thermoplastic fibers. The "substantially orthogonal state" means a state in which fibers intersect at an angle of 70 ° or more and 90 ° or less. The method of measuring the crossing angle between the fibers in the heat-sealed portion P will be described later.

FIG. 1 shows an electron microscope image (observation magnification 200 times) of one surface of the non-woven fabric of the present embodiment taken according to [a method for measuring a substantially orthogonal fused portion ratio] described later.
As shown in FIG. 1, the non-woven fabric of the present embodiment has a plurality of heat-sealed portions P in which the intersections of the thermoplastic fibers contained as constituent fibers are heat-sealed, and the heat-sealed portions P are described above. It has a substantially orthogonal fused portion C. In FIG. 1, as the heat-sealed portion P, a parallel-type fused portion E in which the fibers are fused in a state where the fibers are not orthogonal to each other is formed. The "non-orthogonal state" includes a state in which the fibers are parallel to each other and a state in which the fibers are substantially parallel to each other. Specifically, the crossing angle between the fibers in the parallel type fused portion E is 0 ° or more and less than 70 °. In FIG. 1, the portions marked with reference numerals P1 to P7 are heat fusion portions, the portions with reference numerals C are substantially orthogonal fusion portions, and the portions with reference numerals E are parallel fusion portions.

The non-woven fabric has two surfaces, a first surface and a second surface, which are separated in the thickness direction along the direction orthogonal to the thickness direction of the non-woven fabric. The non-woven fabric of the present embodiment is observed when an observation region of 500 μm × 400 μm (hereinafter, simply referred to as “observation region”) is observed at a magnification of 200 times on at least one of the first surface and the second surface. The ratio of the number of substantially orthogonal fused portions C to the number of heat fused portions P existing in the region is 35% or more. Such a ratio is hereinafter referred to as a "substantially orthogonal fusion portion ratio". The substantially orthogonal fused portion ratio is measured by the following method.

[Measurement method of substantially orthogonal fusion part ratio]
With respect to the non-woven fabric to be measured, a region of 10 mm × 30 mm in a plan view is cut out over the entire thickness direction using a sharp razor, and this is used as a measurement sample. Magnification of 200 times using a scanning electron microscope (Scanning Electron Microscope: SEM, JCM-6000 trade name, manufactured by JEOL Ltd., all SEMs in the present specification) of the measurement sample. Then, a region (observation region) of 500 μm × 400 μm is photographed. In this SEM imaging, the fibers located on the outermost surface of the surface to be photographed of the measurement sample are focused. For one measurement sample, five points having different positions from each other are photographed to obtain a total of five SEM images. Next, in the SEM image, focused fibers are selected, and the number of heat-sealed portions P in which these fibers are heat-sealed is counted. A "focused fiber" is a fiber whose contour is not blurred within the observation area. Next, one of the smaller vertical angles among the four angles formed by the selected fibers in the heat-sealing portion P is measured as the crossing angle between the fibers, and the crossing angle is 70 ° or more and 90 as described above. It is determined whether or not the heat-sealed portion P is a substantially orthogonal type fused portion C based on whether or not the temperature is equal to or less than °. Then, among the heat-sealed portions P, the number of substantially orthogonal type fused portions C in which the fibers are fused to each other in a substantially orthogonal state is counted. The heat-sealing portion P and the substantially orthogonal fusion portion C are counted in each SEM image, and the ratio of the number of the substantially orthogonal fusion portions C to the number of the heat fusion portions P, that is, "substantially orthogonal fusion portion" The percentage of "the number of C / the number of heat-sealed portions P" is obtained. Such a ratio is obtained for each SEM image, and the average of these is taken as a substantially orthogonal fusion portion ratio on one side of the non-woven fabric.

The counting methods of the heat-sealing portion P and the substantially orthogonal fusion-bonding portion C existing in each observation region will be specifically described with reference to FIGS. 1 and 2. First, the fiber located on the outermost surface focused in the SEM image and the fiber heat-sealed with the fiber are selected. In FIG. 1, the fiber a1 is the outermost fiber, and together with the fiber a1, the fiber whose diametrical end of the fiber is not blurred in the observation region of 500 μm × 400 μm is defined as a “focused fiber”. select. Next, the heat-sealed portion P in which the selected fibers are heat-sealed is selected and counted. In FIG. 1, since the heat-sealed fiber at the portion indicated by the reference numeral P2 is not a “focused fiber”, the heat-sealed portion indicated by P2 is excluded. That is, in FIG. 1, six heat-sealing portions P are present on the outermost surface. Next, one of the smaller vertical angles among the four angles formed by the fibers F in each of the selected heat-sealing portions P is measured as the crossing angle θ between the fibers F (see FIG. 2). The heat-sealing portion P having an intersection angle θ (not shown in FIG. 1) of 70 ° or more is a substantially orthogonal fusion portion C, and the heat fusion portion P having an intersection angle of less than 70 ° is a parallel-type fusion portion. Judged as wearing part E. In FIG. 1, of the five heat fusion portions P, three of P1, P4, and P7 are substantially orthogonal fusion portions C, and the remaining two of P3 and P6 are parallel fusion portions E. Is. Similar selections and judgments are made for all "focused fibers" in the same SEM image. Therefore, the substantially orthogonal fused portion ratio in FIG. 1 is 60%. The surface of the non-woven fabric is not flat but has undulations microscopically. Therefore, the "fibers located on the outermost surface" in the observation region are fibers located within a range of approximately 100 μm from the most surface side to the inside in the thickness direction of the nonwoven fabric, and are most exposed to the surface side. The "focused fibers" in the observation region are also located within a range of approximately 100 μm from the surface side to the inside in the thickness direction of the non-woven fabric.

The nonwoven fabric of the present embodiment contains fibers having a fiber diameter of 15 μm or less (hereinafter, also referred to as “fine fibers”). The non-woven fabric of the present embodiment has fine fibers on the first surface or the second surface, but the non-woven fabric may contain fine fibers inside.
The presence of fine fibers on the first surface or the second surface can be confirmed by the presence or absence of fine fibers observed in the observation region of [Method for measuring fine fiber ratio] described later.

Regarding the non-woven fabric of the present embodiment, at least one of the first surface and the second surface has a substantially orthogonal fusion portion ratio of 35% or more and a fine fiber ratio in the observation region of 20% or more. .. The fine fiber ratio represents the abundance ratio of fine fibers existing in the observation area. Such an observation area is synonymous with the observation area in the above-mentioned [method for measuring the substantially orthogonal fused portion ratio].
From the viewpoint of further improving the smooth feel, at least one of the first surface and the second surface has a fine fiber ratio of preferably 25% or more, more preferably 30% or more.
The fine fiber ratio is practically 100% or less for at least one of the first surface and the second surface.
The fine fiber ratio is determined by the following method by surface observation. When the fine fibers can be confirmed by the following surface observation, that is, when the fine fibers are present on at least one of the first surface and the second surface of the non-woven fabric, the texture peculiar to the fine fibers and the smoothness when touched by hand are more favorable. It is effective in that it can be surely obtained.

[Measurement method of fine fiber ratio]
A measurement sample is cut out by the same method as the above-mentioned [Measurement method of substantially orthogonal fused portion ratio], and SEM images corresponding to the observation region on one surface of one measurement sample (5 images on each side). To get. For each of the acquired SEM images, the fine fiber ratio is measured by the following method. First, in the SEM image, the "focused fiber" is selected. Next, for each of the focused fibers, an arbitrary portion other than the heat-sealed portion P is selected, and a line orthogonal to the longitudinal direction of the fiber in the selected portion is drawn. The transfer length of the fibers along the orthogonal lines is measured as the fiber diameter. In such a measurement, in the focused fiber, the transfer line indicating the transfer length, that is, the line orthogonal to the longitudinal direction of the fiber and the line indicating the contour of the fiber are measured at positions orthogonal to each other. Next, the number of fibers having a fiber diameter of 15 μm or less is counted as the number of fine fibers, and the ratio of the number of the fine fibers to the number of the focused fibers in the SEM image, that is, “number of fine fibers / focusing). Calculate the percentage (%) of "the number of fibers". Such a ratio is obtained for each of a total of five SEM images obtained from the measurement sample, and the average of these is taken as the "fine fiber ratio". The "fine fiber ratio" is measured on both sides of the non-woven fabric.

The non-woven fabric of the present embodiment has a fine fiber ratio of 20% or more on at least one of the first surface and the second surface, and a substantially orthogonal type fused portion ratio of 35%.
The non-woven fabric of the present embodiment may have a fine fiber ratio of 20% or more and a substantially orthogonal type fused portion ratio of 35% on both the first surface and the second surface.

Since the non-woven fabric of the present embodiment has a fine fiber ratio of at least one of the first surface and the second surface of 20% or more, it is smooth to the touch and has a good texture. Moreover, even though it contains fine fibers, the ratio of the substantially orthogonal fused portion on at least one surface is 35% or more, so that the width shrinkage due to the elongation of the non-woven fabric is unlikely to occur. Since the substantially orthogonal type fused portion ratio is the abundance rate of the portion fused in a state where the fibers are orthogonal to each other, it is considered that the orientation of the constituent fibers is dispersed in a plurality of directions in the nonwoven fabric of the present embodiment. .. Even if this non-woven fabric is to be stretched in one direction, it is difficult to stretch in that direction.
This can be easily understood from the comparison between FIGS. 2 and 3. If the orientation of the constituent fibers is as shown in FIG. 3 and the number of parallel type fusion parts E is larger than the number of substantially orthogonal type fusion parts C, the parallel type fusion parts E have the same direction (FIG. 3). Since the fibers extending in the middle and Y directions are fused to each other, it is difficult to limit the elongation of the fibers extending in a direction different from the same direction (X direction in FIG. 3). On the other hand, in FIG. 2, since the orientation of the fibers F in the non-woven fabric is different in multiple directions, the fibers F1 extending in a direction different from the one direction (X direction in FIG. 2) (Y direction in FIG. 2). Is difficult to stretch, and the fibers F extending along the one direction are restricted from being stretched between the substantially orthogonal fused portions C (see FIG. 2), so that the entire non-woven fabric is difficult to stretch in the one direction. it is conceivable that. As a result, width shrinkage due to elongation can be effectively suppressed.
Such an effect is effective when producing a non-woven fabric product such as an absorbent article. For example, at the time of manufacturing a non-woven fabric product, the non-woven fabric is generally transported in a state where tension is applied in the transport direction (machine direction), and may be in an elongated state along the transport direction. It can be said that the higher the maximum elongation in the conveying direction of the nonwoven fabric under such a state, the higher the extensibility in the conveying direction with respect to the tension applied to the nonwoven fabric. Further, it is clear that the width of the non-woven fabric becomes smaller as the non-woven fabric stretches in the transport direction. Therefore, the maximum elongation in the conveying direction (mechanical direction) of the nonwoven fabric can be used as an index of the width shrinkage, and suppressing the maximum elongation in the conveying direction leads to suppressing the width shrinkage, and the production of the nonwoven fabric. Efficiency can be improved.
Even if tension is applied to the nonwoven fabric of the present embodiment, it is difficult to stretch in the conveying direction and the maximum elongation in the conveying direction is suppressed, that is, width shrinkage is unlikely to occur. Dimensional defects due to width shrinkage are unlikely to occur. Further, since the non-woven fabric of the present embodiment can be transported at a high speed in which tension is easily applied, the production efficiency of the non-woven fabric product can be improved by using the non-woven fabric.

Normally, when fine fibers are included, the number of fibers per basis weight is naturally larger than that of thicker fibers. Therefore, the contact area between the fibers tends to be large, so that a parallel type fused portion as shown in FIG. 3 is generally likely to occur. However, even if the non-woven fabric of the present embodiment contains fine fibers, for example, even if the fine fiber ratio on at least one of the two surfaces is as high as 20% or more, a substantially orthogonal fusion type fusion is performed. When the portion ratio is 35% or more, the orientation of the fiber F is easily dispersed in multiple directions, and the abundance ratio of the substantially orthogonal fused portion C to the heat fused portion P is sufficient, so that the elongation of the fiber is restricted. The effect of suppressing the width shrinkage is also high.

From the viewpoint of further suppressing the width shrinkage, the substantially orthogonal fusion portion ratio is preferably 50% or more, more preferably 52% or more.
Further, from a practical viewpoint as a non-woven fabric structure, the substantially orthogonal type fused portion ratio is preferably 80% or less, more preferably 70% or less.
The substantially orthogonal fused portion ratio is preferably 50% or more and 80% or less, and more preferably 52% or more and 70% or less.

From the viewpoint of further suppressing the width shrinkage, the total number of substantially orthogonal fused portions C existing in the five observation regions is preferably 15 or more, more preferably 20 or more.
Further, from a realistic viewpoint as a non-woven fabric structure, the total number of substantially orthogonal fused portions C existing in the five observation regions is preferably 50 or less, more preferably 40 or less.
The total number of substantially orthogonal fused portions C existing in the five observation regions is preferably 15 or more and 50 or less, and more preferably 20 or more and 40 or less.
The total number of substantially orthogonal fused portions C existing in the five observation regions is approximately the same as in the above-mentioned [method for measuring the substantially orthogonal fused portion ratio] in a total of five SEM images. It is the total number of orthogonal fusion portions C.

The substantially orthogonal type fused portion ratio is preferably in the above range on the outermost surface of the non-woven fabric from the viewpoint of further suppressing width shrinkage. On the other hand, from the viewpoint of making the non-woven fabric softer, it is preferable that the substantially orthogonal fusion portion ratio inside the outermost surface in the thickness direction of the nonwoven fabric is smaller than the substantially orthogonal type fusion portion ratio of the outermost surface. It is more preferable that the substantially orthogonal type fused portion ratio on the inner side is less than 50%.
The total number of substantially orthogonal fused portions C existing in the five observation regions is preferably in the above range on the outermost surface of the non-woven fabric from the viewpoint of further suppressing width shrinkage. On the other hand, from the viewpoint of softening the non-woven fabric, the total number of substantially orthogonal fused portions C existing in the five observation regions is smaller on the inner side of the outermost surface in the thickness direction of the non-woven fabric than on the outermost surface. Is preferable, and the total number of the substantially orthogonal type fused portions C on the inner side is more preferably less than 15.
The ratio of the substantially orthogonal fused portions inside the outermost surface of the nonwoven fabric and the total number of the substantially orthogonal fused portions C existing in the five observation regions on the inner side so as to divide the thickness of the nonwoven fabric into two equal parts. The measurement is performed by the same method as the above-described [method for measuring the substantially orthogonal type fused portion ratio] except that the cut surface is used as the surface to be imaged.

The non-woven fabric can sufficiently obtain the effect of width shrinkage if the substantially orthogonal fusion portion ratio on either one of the first surface and the second surface is equal to or more than the above lower limit. For example, when the above-mentioned substantially orthogonal type fusion zone ratio is measured for each of both sides of the non-woven fabric, it is sufficient that either one side is equal to or more than the above lower limit.

It is preferable that the non-woven fabric of the present embodiment has substantially orthogonal fusion portions ratios on the first surface and the second surface, respectively. In this case, for example, the surface having the higher ratio of the substantially orthogonal fused portion is designated as the first surface.
When the substantially orthogonal fusion portion ratios on the first surface and the second surface are different from each other, the substantially orthogonal fusion portion ratio described above or the substantially orthogonal fusion portion C existing in the five observation regions It is preferable that either one of the first surface and the second surface satisfies the preferable configuration such as the total number and the range thereof.

The basis weight of the non-woven fabric is practically preferably 5 g / m ² or more, and more preferably 8 g / m ² or more from the viewpoint of producing the non-woven fabric.
From the viewpoint of the cost of the non-woven fabric, the basis weight of the non-woven fabric is preferably 30 g / m ² or less, more preferably 26 g / m ² or less.
The basis weight of the non-woven fabric is preferably 5 g / m ² or more and 30 g / m ² or less, and more preferably 8 g / m ² or more and 20 g / m ² or less.

From the viewpoint of a realistic fiber diameter in the production of a non-woven fabric, the average fiber diameter of the constituent fibers in the non-woven fabric is preferably 5 μm or more, more preferably 8 μm or more.
Further, from the viewpoint of further improving the smoothness, the average fiber diameter of the constituent fibers in the non-woven fabric is preferably 30 μm or less, more preferably 20 μm or less.
The average fiber diameter of the constituent fibers in the non-woven fabric is preferably 5 μm or more and 30 μm or less, and more preferably 8 μm or more and 20 μm or less.
The non-woven fabric may be composed of a plurality of types of fibers having different fiber diameters, but from the same viewpoint as described above, the non-woven fabric is preferably composed of constituent fibers having a fiber diameter of 15 μm or less, and is composed of constituent fibers having a fiber diameter of 13 μm or less. Is more preferable. When the nonwoven fabric contains a plurality of types of fibers having different fiber diameters, the "average fiber diameter" is the average of the fiber diameters of the constituent fibers in the entire nonwoven fabric. The average fiber diameter is determined by the following method. When different fibers are mixed in the non-woven fabric, it is considered that all the fibers affect the structure forming the fusion, so the average of the entire non-woven fabric is calculated.

The fiber diameter of the constituent fibers of the non-woven fabric is determined by the following method. The non-woven fabric is SEM-observed by the same method as the above-mentioned [Measuring method of fine fiber ratio]. Arbitrarily 10 of the above-mentioned "focused fibers" in the SEM image of the non-woven fabric obtained by this observation is selected. Next, the fiber diameter described above is measured for each of these 10 fibers. Next, the arithmetic mean value of the fiber diameter is obtained for the 10 fibers for each of a total of 5 SEM images obtained from the measurement sample. Such an arithmetic mean value is obtained for each of both sides of the non-woven fabric, and the average of these values is taken as the average fiber diameter.

From the viewpoint of obtaining a non-woven fabric having a soft texture, the non-woven fabric of the present embodiment preferably has a maximum elongation of 20% or more, more preferably 25% or more.
Further, from the viewpoint of further suppressing width shrinkage in high-speed transportation, the maximum elongation is preferably 60% or less, more preferably 55% or less.
The maximum elongation is preferably 20% or more and 60% or less, and more preferably 25% or more and 55% or less.
Maximum elongation is measured by the following method.

[Measurement method of maximum elongation]
The non-woven fabric to be measured is cut into a size of 50 mm × 200 mm using a sharp razor, and this is used as a measurement sample. At this time, the measurement sample is cut out so that the longitudinal direction of the measurement sample coincides with the orientation direction of the fibers in the non-woven fabric. Prepare four measurement samples.
The orientation direction of the fibers is confirmed by observing one surface side of the non-woven fabric using a scanning electron microscope JCM-6000 (manufactured by JEOL Ltd.). Prior to such observation, the non-woven fabric is vapor-deposited in advance by the method recommended in the manual of the scanning electron microscope. The non-woven fabric is observed with the scanning electron microscope at a magnification of 50 times, and a square having a side of 500 μm with the center of the screen of the observation field as the intersection of diagonal lines is drawn. This square is set so that the sides of the square are parallel to the longitudinal direction or the lateral direction of the non-woven fabric. Next, among the square sides on the screen, the number of fibers extending from one side to the other of the two sides parallel to the longitudinal direction of the non-woven fabric and facing each other is counted. Let the number of fibers be "the number of fibers i". Similar to the above, the number of fibers extending from one side to the other of the two sides parallel to the lateral direction of the non-woven fabric and facing each other is counted. The number of fibers is referred to as "number of fibers ii". The orientation of the fiber having the larger number of fibers out of the number of fibers i and the number of fibers ii is defined as the orientation direction of the fibers in the non-woven fabric. For example, when the number of fibers i extending between two sides parallel to the longitudinal direction of the nonwoven fabric is large, it can be determined that the orientation direction of the fibers in the nonwoven fabric coincides with the lateral direction of the nonwoven fabric. In this case, the measurement sample is cut out so that the longitudinal direction of the measurement sample coincides with the lateral direction of the non-woven fabric.

Next, with the orientation direction of the fibers in the measurement sample, that is, the longitudinal direction of the measurement sample aligned with the tensile direction, both ends of the measurement sample are subjected to a tensile tester (manufactured by Shimadzu Corporation, model "AUTOGRAPH AG-X"). This is all the tensile testers in the specification of the present application.) The distance between the chucks is 150 mm. The measurement sample attached between the chucks is stretched at a speed of 300 mm / min, the tensile strength (load) is measured, and the elongation at the maximum tensile strength is determined. "Elongation" is the ratio (%) of the length after elongation to the natural length before elongation. For example, 100% elongation means that the length is twice as long as the natural length. The above elongation is measured for each measurement sample, and the average value thereof is taken as the maximum elongation.

If it is unclear from the above observation which direction the fibers are oriented, the maximum elongation is determined by the following method. First, a measurement sample in which the longitudinal direction of the measurement sample and the longitudinal direction of the non-woven fabric to be measured coincide with each other, and a measurement sample in which the longitudinal direction of the measurement sample and the lateral direction of the non-woven fabric to be measured coincide with each other are cut out. The above tensile test is performed on these two types of measurement samples, and the value with the higher breaking strength is taken as the maximum elongation. This is because it is generally known that the breaking strength due to a tensile load along the fiber orientation direction is higher than the breaking strength due to a tensile load not along the fiber orientation direction.
When the non-woven fabric to be measured is incorporated in a non-woven fabric product such as an absorbent article, the measurement sample in which the longitudinal direction of the measurement sample and the longitudinal direction of the product coincide with each other, and the longitudinal direction of the measurement sample and the short length of the product. A measurement sample that matches the hand direction will be cut out.
When cutting out the measurement sample, if the above-mentioned size cannot be obtained, the length in the lateral direction is set to 50 mm, and the length in the longitudinal direction is shortened in increments of 50 mm (for example, 50 mm × 150 mm or 50 mm ×). 100 mm), cut out a measurement sample. In this case, the distance between the chucks of the tensile tester is 50 mm shorter than the length of the measurement sample in the longitudinal direction. As described above, even if the length of the measurement sample in the longitudinal direction is changed, the measurement result of the maximum elongation can be compared as it is.

The non-woven fabric of the present embodiment is typically mainly composed of thermoplastic fibers. The proportion of the thermoplastic fiber in the total constituent fibers of the nonwoven fabric of the present embodiment is at least 50% by mass or more, preferably 90% by mass or more, and 100% by mass or less.

Examples of the constituent resin (thermoplastic resin) of the thermoplastic fiber include polyolefins such as polyethylene (PE) and polypropylene (PP); polyesters such as polyethylene terephthalate (PET); polyamides such as nylon 6 and nylon 66; polyacrylic acid. , Polymethacrylic acid alkyl ester, polyvinyl chloride, polyvinylidene chloride and the like, and one of these can be used alone or in combination of two or more.

Synthetic fibers such as thermoplastic fibers used for the non-woven fabric of the present embodiment may be single fibers made of one kind of synthetic resin or a blend polymer in which two or more kinds of synthetic resins are mixed, or may be composite fibers. The composite fiber referred to here is a synthetic fiber obtained by combining two or more kinds of synthetic resins having different components with a spinneret and spinning them at the same time, and has a structure in which a plurality of components are continuous in the length direction of the fiber. Those that are mutually bonded in the fiber. Examples of the form of the composite fiber include a core-sheath type having a core-sheath structure composed of a core portion and a sheath portion, a side-by-side type, and the like.

The thermoplastic fiber preferably contains PE as a constituent resin, more preferably contains PE at least on the surface, and further preferably consists of PE.
For example, when the thermoplastic fiber contains a fiber having a core-sheath structure, it is preferable that the resin component of the core portion is PET and the resin component of the sheath portion is PE.

As a preferable example of the thermoplastic fiber, it is a thermoplastic fiber composed of a core-sheath type composite fiber, and the core component is selected from one or more selected from the group consisting of PET and PP, and the sheath component is selected from the group consisting of PE. There is one or more kinds to be given. In the core-sheath type composite fiber, the fibers are fused only to the sheath portion, and the core portion remains without being fused, so that the core portion has a role of suppressing the elongation of the fiber. Therefore, the thermoplastic fiber made of the core-sheath type composite fiber is preferable from the viewpoint of suppressing the elongation of the fiber and suppressing the width shrinkage.

Further, the thermoplastic fiber is preferably a short fiber. Short fibers are fibers having a fiber length of less than 80 mm. It is preferable to form a web using short fibers because the orientation of the fibers is easily dispersed and a substantially orthogonal fused portion is easily formed as shown in FIG. In such a case, the non-woven fabric of the present embodiment does not include the spunbonded non-woven fabric.

In the non-woven fabric of the present embodiment, the contact probability between the thermoplastic fibers is reduced by adding the fibers that are not heat-sealed in addition to the thermoplastic fibers, and it is easier to form a substantially orthogonal type fused portion than the parallel type fused portion. , Other fibers may be contained. Examples of such other fibers include natural fibers such as pulp and cotton, cellulosic fibers such as rayon, lyocell and tencel, and one of these fibers may be used alone or in combination of two or more. Can be done.
In particular, it is preferable to use a PET / PE core-sheath composite fiber mixed with cotton.

From the same viewpoint as above, the ratio of other fibers to the total constituent fibers of the non-woven fabric is preferably 0.5% by mass or more, more preferably 1% by mass or more.
Further, from the viewpoint of maintaining the breaking strength, the ratio is preferably 20% by mass or less, more preferably 10% by mass or less.
The ratio is preferably 0.5% by mass or more and 20% by mass or less, and more preferably 1% by mass or more and 10% by mass or less.

The non-woven fabric of this embodiment is used for non-woven fabric products. A non-woven fabric product is a product made of a non-woven fabric or a product including the non-woven fabric as a constituent member. Examples of non-woven fabric products include absorbent articles such as disposable diapers and napkins, heating devices such as eye mask types, surgical clothing and masks, cleaning sheets, and cleaning sheets. The "absorbable article" includes a wide range of articles used for absorbing body fluids (urine, loose stool, menstrual blood, sweat, etc.) discharged from the human body, and includes, for example, disposable diapers, sanitary napkins, sanitary shorts, and the like. Incontinence pads and the like are included.

Absorbent articles typically have a liquid-permeable surface sheet located relatively close to the wearer's skin and a liquid-impermeable surface sheet located relatively far from the wearer's skin. Alternatively, it is provided with a liquid-impermeable or water-repellent back sheet and a liquid-retaining absorber disposed between the two sheets. The absorbent article may include an exterior body that forms its outer surface.
When the non-woven fabric of the present embodiment is used as an absorbent article, the absorbent article includes the non-woven fabric as a constituent member.

The non-woven fabric of the present embodiment is made of the non-woven fabric single layer, but when used as a constituent member of an absorbent article, it is in a state of being laminated with other sheet materials such as other non-woven fabrics and films. May be.

When the non-woven fabric of the present embodiment is used as a constituent member of the non-woven fabric product, the first surface of the non-woven fabric is arranged so as to form the surface of the non-woven fabric product from the viewpoint of more reliably obtaining a smooth touch. Is preferable.
For example, in the absorbent article in which the non-woven fabric of the present embodiment is used, it is preferable to use the non-woven fabric as the outermost sheet. Specifically, the non-woven fabric of the present embodiment is preferably provided as either one or both of the front surface sheet and the back surface sheet, and more preferably the non-woven fabric is provided as the back surface sheet.
In the non-woven fabric of the present embodiment, the surface of the absorbent article, preferably the one having the higher ratio of the substantially orthogonal fused portion, is arranged so as to face the outer surface of the absorbent article. Specifically, when the non-woven fabric of the present embodiment is used as a surface sheet, the surface having a substantially orthogonal fusion portion ratio is arranged so as to form a skin-facing surface. Further, when the nonwoven fabric of the present embodiment is used as a back sheet, the surface having a substantially orthogonal fusion portion ratio is arranged so as to form a non-skin facing surface. From the viewpoint of ensuring leak resistance more reliably, such a back surface sheet is preferably made of a laminated sheet of a liquid impervious sheet and the non-woven fabric.
The skin-facing surface is a surface of the absorbent article that is directed toward the wearer's skin, and the non-skin-facing surface is a surface that is directed to the side opposite to the wearer's skin or is directed to clothing such as shorts.

From the viewpoint of facilitating a soft and pleasant feel, the nonwoven fabric of the present embodiment is arranged so that the side of the absorbent article having a substantially orthogonal fusion portion ratio faces the inner surface of the absorbent article. It is preferable that it is. Specifically, when the nonwoven fabric of the present embodiment is used as a surface sheet, it is preferable that the surface having a substantially orthogonal fusion portion ratio is arranged so as to form a non-skin facing surface. Further, when the non-woven fabric of the present embodiment is used as a back sheet, it is preferable that the surface having a substantially orthogonal fusion portion ratio is arranged so as to form a skin-facing surface.

When the non-woven fabric of the present embodiment is incorporated in a non-woven fabric product such as a commercially available absorbent article, cold spray or liquid nitrogen is used to solidify the adhesive adhering the constituent members of the non-woven fabric product, and each member is solidified. Take out the non-woven fabric by carefully peeling it off. When the non-woven fabric to be measured is taken out from the non-woven fabric product, this taking-out method is common to other measurements in the present specification.

Next, the method for producing the nonwoven fabric of the above-described embodiment will be described. The production method includes a heat treatment step of heating a fiber web containing thermoplastic fibers. The heat treatment step is a step of forming a non-woven fabric by fusing the intersections of the constituent fibers of the fiber web to form a heat-sealed portion.

The fiber web is typically produced by opening a raw material fiber such as a thermoplastic fiber with a fiber opening machine and converting the opened raw material fiber into a web with a card machine. The fiber web is a sheet before it is formed into a non-woven fabric, and the fibers are not heat-sealed in the fiber web. As the raw material fiber, that is, the constituent fiber of the fiber web, it is preferable to use the same one as the constituent fiber of the non-woven fabric described above. Further, it is preferable that the basis weight of the fiber web is adjusted to the range of the basis weight of the above-mentioned non-woven fabric.
The fiber web may be formed by laminating or mixing a plurality of types of fibers having different fiber diameters.

From the viewpoint of more reliably adjusting the fine fiber ratio so that the fine fiber ratio on the first surface or the second surface is within the above range, the fiber web preferably has a ratio of fine fibers to all constituent fibers of 20. % Or more, more preferably 25% or more, still more preferably 30% or more.
The ratio is practically 100% or less.
The ratio of fine fibers to all constituent fibers of the fiber web is the ratio of fine fibers to all constituent fibers of the obtained nonwoven fabric.
The ratio of the fine fibers to the total constituent fibers of the fiber web is the ratio (%) of the mass of the fine fibers to the mass of all the constituent fibers constituting the fiber web, and is based on the mass of the fibers used when producing the non-woven fabric. Can be obtained.

In the heat treatment step, the fiber web being conveyed may be continuously heat-treated to form a non-woven fabric, or a predetermined amount of fiber web may be intermittently heat-treated to form a non-woven fabric. From the viewpoint of more easily forming the substantially orthogonal fused portion C, the fiber web is preferably heat-treated in a state where the fiber orientations are arranged so as to intersect each other, and the fiber orientations are orthogonal to each other. It is more preferable that the heat treatment is performed in such an arranged state. For example, a method of heat-treating a laminated web in which a plurality of fiber webs are stacked so that the orientation direction of the fibers differs for each fiber web can be mentioned. The orientation direction of the fibers in the fiber web is usually along the mechanical direction (MD direction) at the time of manufacturing the fiber web. Further, the web in which the fibers are oriented along the MD direction may be oriented in the CD direction before the heat treatment. In this case, for example, a method of spreading the web in the CD direction can be mentioned. The CD direction is a direction orthogonal to the MD direction. The above-mentioned treatment for differentiating the orientation of fibers in the fiber web is also referred to as "orientation adjustment treatment".

In the heat treatment step, any heating method capable of heating the fiber web to form a heat-sealed portion can be adopted. Examples of such a heating method include a method of blowing hot air on the fiber web by an air-through method to heat the fiber web, a method of heating the fiber web in a windless and predetermined temperature environment, and the like.

The air-through method is a heating method in which a fluid having a temperature higher than a predetermined temperature, for example, hot air such as air or water vapor, is blown onto a fiber web or a non-woven fabric which is a precursor of the non-woven fabric. The spraying of such a fluid is performed by a so-called air-through method (penetration method) in which a fluid such as hot air penetrates the fiber web or the non-woven fabric. When the non-woven fabric of the present embodiment is produced by a heat treatment step by an air-through method, the non-woven fabric is a non-woven fabric produced by adding the heat treatment step to a non-woven fabric produced by another method, or some step after the heat treatment step. The non-woven fabric produced by the above is included.

The heat treatment process using the air-through method will be explained. In such a step, the fiber web is placed on, for example, a resin mesh belt, a metal endless net made of wire mesh, a metal plate with vents, or a metal plate with no vents. By blowing hot air or steam from the fiber web side, the intersections of the fibers are heat-sealed. As a result, the obtained non-woven fabric is formed with two surfaces, a surface facing the plate or net (hereinafter, also referred to as a non-sprayed surface) and a surface for which hot air is sprayed (hereinafter, also referred to as a sprayed surface). Of these two surfaces in such a non-woven fabric, many heat-sealed portions are formed on one surface. The surface is typically a surface having a substantially orthogonal heat-sealed portion ratio as compared with the other surface.

The temperature of the hot air in the normal air-through method is set in a range about 10 ° C. higher than the lowest melting point of the constituent fibers of the fiber web (for example, the melting point in the sheath portion of the core-sheath type composite fiber). From the viewpoint of more easily forming the heat-sealed portion P, the temperature difference between the temperature of the hot air and the minimum melting point of the constituent fibers is preferably 5 ° C. or higher, more preferably 10 ° C. or higher.
The temperature difference between the temperature of the hot air and the minimum melting point of the constituent fibers is preferably 70 ° C. or lower, more preferably 50 ° C. or lower.
For example, in a web containing core-sheath type composite fibers, when polyethylene is used for the sheath portion of the fibers, the temperature of hot air in the heat treatment step is preferably 125 ° C. or higher, more preferably 130, from the same viewpoint as above. It is above ℃.
The temperature of the hot air is preferably 190 ° C. or lower, more preferably 170 ° C. or lower.
The lowest melting point of the constituent fibers refers to the melting point of the lowest melting point among the resins when the fibers have a plurality of types of resins such as core-sheath type composite fibers. In the case of a resin that does not have a definite melting point, it refers to the softening point.

From the viewpoint of further improving the production efficiency of the non-woven fabric in the heat treatment step using the air-through method, the wind speed of the hot air blown to the fiber web is preferably within the following range.
The wind speed of the hot air blown onto the fiber web is more than 0 m / sec, preferably 0.3 m / sec or more, and more preferably 0.5 m / sec or more.
The wind speed of the hot air blown onto the fiber web is preferably 5 m / sec or less, more preferably 3 m / sec or less, still more preferably 2 m / sec or less.

In the heat treatment step using the air-through method, the time for blowing hot air on the fiber web (heat treatment time) may be about the same as that of the conventional method for producing an air-through non-woven fabric, but from the same viewpoint as above, the heat treatment time is set. It is preferably within the following range.
The heat treatment time is preferably 1 second or longer, more preferably 3 seconds or longer.
Further, from the viewpoint of increasing the production speed as much as possible and further reducing the production cost, the heat treatment time is preferably 60 seconds or less, more preferably 30 seconds or less.

The heat treatment process when the method of heating the fiber web in a windless and predetermined temperature environment is adopted will be described. In such a step, the fiber web is, for example, a resin mesh belt, a metal endless net made of wire mesh, a metal plate with vents, a metal plate without vents, or the like. By placing it on a surface and leaving it in an environment of a predetermined temperature or higher, the intersections of the fibers are heat-sealed. As a result, the obtained non-woven fabric is formed with two surfaces, a surface facing the mounting surface of the mesh belt or the like and a surface opposite to the surface. Of these two surfaces of such a non-woven fabric, the surface of the mesh belt or the like facing the mounting surface tends to be smooth and tends to have a good texture. The surface is typically a surface having a substantially orthogonal heat-sealed portion ratio as compared with the other surface.

From the viewpoint of more easily forming the heat-sealed portion P, the method of heating in a windless and predetermined temperature environment is the temperature at which the fiber web is heated (hereinafter, also referred to as “heating environment temperature”) and the minimum melting point of the constituent fibers. The temperature difference from the above is preferably 5 ° C. or higher, more preferably 10 ° C. or higher.
The temperature difference is preferably 70 ° C. or lower, more preferably 50 ° C. or lower.
From the same viewpoint as above, the heating environment temperature in the heat treatment step is preferably 125 ° C. or higher, more preferably 130 ° C. or higher.
When the core-sheath type composite fiber is used, the heating environment temperature is preferably 190 ° C. or lower, more preferably 170 ° C. or lower, from the viewpoint of maintaining the fiber morphology better.

From the same viewpoint as above, in this heat treatment step, the time for heating the fiber web under the heating environment temperature (heat treatment time) is preferably 1 second or longer, more preferably 3 seconds or longer.
Further, from the viewpoint of not applying heat more than necessary to the entire non-woven fabric, the heat treatment time is preferably 180 seconds or less, more preferably 120 seconds or less.

When a non-woven fabric product such as the above-mentioned absorbent article includes other constituent members in addition to the non-woven fabric of the present embodiment, the method for producing such a non-woven fabric product is the non-woven fabric of the present embodiment and the non-woven fabric product. It includes a step of superimposing the other constituent members. From the viewpoint of improving the feel of the non-woven fabric product, particularly the smooth feel, in such a step, the non-woven fabric of the present embodiment has a surface having a substantially orthogonal heat-sealed portion ratio facing the other constituent members. And the other constituent members are preferably overlapped with each other. Further, from the viewpoint of improving the soft feel, in the above step, the non-woven fabric of the present embodiment and the other configuration are configured so that the surface having the substantially orthogonal heat-sealed portion ratio faces the other constituent members. It is preferable to superimpose the members. A non-woven fabric product is formed by integrating the laminated non-woven fabric and other constituent members by a known joining means such as an adhesive.

Although the present invention has been described above based on the preferred embodiment, the present invention is not limited to the above embodiment and can be appropriately modified. Further, each of the above-described configurations may be combined as appropriate.
For example, in the non-woven fabric in the above-described embodiment, the substantially orthogonal fusion portion C is present on both sides thereof, but the substantially orthogonal fusion portion C may be present only on one of the surfaces.

When the upper limit value or the lower limit value or the upper and lower limit values of the numerical value is specified in this specification, the value of the upper limit value and the lower limit value itself is also included. In addition, it is interpreted that all numerical values or numerical ranges within the upper and lower limit values or the upper and lower limit values are described even if not specified.
In the present specification, "a", "an" and the like are interpreted as one or more meanings.
In light of the above disclosure herein, it is understood that various modifications and modifications of the invention are possible. Therefore, it should be understood that the present invention can be practiced even in embodiments not specified in the present specification within the technical scope based on the description of the claims.
All of the contents of the above-mentioned patent documents are incorporated in the present specification as a part of the contents of the present specification.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to such Examples.

[Example 1]
As the raw material fiber, a thermoplastic fiber made of concentric core-sheath composite fibers (core-sheath ratio 50% by mass: 50% by mass, fineness 1.2dtex, short fiber) having a core component of PET and a sheath component of PE was used. .. Such raw material fibers had a minimum melting point of 120 ° C. Using this raw material fiber, a fiber web was produced using a known card machine according to a conventional method so that the basis weight was 4 g / m ^2. A laminated body in which five fiber webs were stacked was produced so that the mechanical directions (MD directions) at the time of manufacturing the fiber webs were alternately orthogonal to each other. A non-woven fabric was produced by performing a heat treatment step of blowing hot air by an air-through method while the laminate was placed on a resin mesh belt. The heat treatment conditions in the heat treatment step (air-through treatment) are as shown in Table 1.

[Example 2]
Using the raw material fibers of Example 1, a fiber web was produced so that the ^{basis weight was 30 g / m 2} according to a conventional method using a known card machine, and then orientation adjustment treatment was performed. Specifically, the fiber web obtained was expanded in the CD direction to increase the area by 1.5 times so that the length in the CD direction at the time of manufacture was 1.5 times. Then, a non-woven fabric was produced by performing a heat treatment step of blowing hot air under the same heat treatment conditions as in Example 1 while the fabric was placed on a resin mesh belt.

[Example 3]
A non-woven fabric was produced by the same method as in Example 2 except that the heat treatment conditions and the basis weight before the orientation treatment ^{were changed to 37.5 g / m 2.}

[Example 4]
As raw material fibers, 1.2 dtex thermoplastic fibers composed of concentric core-sheath composite fibers (core-sheath ratio 50% by mass: 50% by mass, short fibers) having a core component of PET and a sheath component of PE, and concentric fibers. 2.0 dtex fibers, which are sheath-type composite fibers, were prepared, and these two types of fibers were used separately to laminate the first fiber web (1.2 dtex) and the second fiber web (2.0 dtex). A laminated web was manufactured. Such a laminated web had a composition ratio (mass ratio) of 1st fiber web: 2nd fiber web = 2: 3. The length of these first fiber webs and second fiber webs is 1.5 times longer in the CD direction ^{than the webs (basis weight 37.5 g / m 2} ) manufactured according to a conventional method using a known card machine. It was spread in the same direction and subjected to orientation adjustment treatment. Next, a heat treatment step was performed on the laminated web with the second fiber web side as the spray surface. The heat treatment conditions in the heat treatment step (air-through treatment) are as shown in Table 1. Since the obtained non-woven fabric was composed of the above two types of raw material fibers, the ratio of fine fibers to all the constituent fibers was 40%.

[Example 5]
A non-woven fabric was produced by the same method as in Example 4 except that the composition ratio (mass ratio) of the first fiber web and the second fiber web in the laminated web was 1: 4. The ratio of fine fibers to all the constituent fibers of the obtained non-woven fabric was 20%.

[Example 6]
Using the raw material fibers of Example 1, a fiber web was prepared using a known card machine according to a conventional method so that the basis weight was 25 g / m ^2. A non-woven fabric was produced by the same method as in Example 1 except that the fiber web was heated in a windless environment and in the heating temperature environment shown in Table 1.

[Example 7]
A non-woven fabric was produced by the same method as in Example 6 except that the basis weight of the fiber web was changed.

[Example 8]
A non-woven fabric was produced by the same method as in Example 6 except that the same laminated web as in Example 4 was used.

[Example 9]
A non-woven fabric was produced by the same method as in Example 6 except that the same laminated web as in Example 5 was used.

[Example 10]
Using the same raw material fibers as in Example 4, a laminated web (basis weight 25 g / m ² ) having a basis weight different from that of Example 4 was prepared. This laminated web has the same composition ratio (mass ratio) of the first fiber web and the second fiber web as in Example 4, and was produced by performing an orientation adjustment treatment in the same manner as in Example 4. The laminated web was subjected to a heat treatment step under the heat treatment conditions shown in Table 1 to produce a non-woven fabric.

[Comparative Example 1]
Using the raw material fibers of Example 1, a fiber web was prepared using a known card machine according to a conventional method so that the basis weight was 25 g / m ^2. A non-woven fabric was produced by the same method as in Example 1 except that the fiber web was used.

[Comparative Example 2]
A non-woven fabric was produced by the same method as in Example 3 except that the fiber web was produced so that the basis weight was 30 g / m ^{2 without performing the orientation adjustment treatment.}

[Comparative Example 3]
A non-woven fabric was produced by the same method as in Example 4 except that the laminated web was produced without performing the orientation adjustment treatment.

[Comparative Example 4]
A non-woven fabric was produced by the same method as in Example 3 except that the fiber web was produced so that the basis weight was 25 g / m ^{2 without performing the orientation adjustment treatment.}

For each of both sides of the non-woven fabrics of Examples and Comparative Examples, the total number of substantially orthogonal fused portions and the total number of parallel fused portions existing in the five observation regions were measured by the above-mentioned method. Further, for each of both sides of the non-woven fabric, the substantially orthogonal type fused portion ratio (%) was determined by the above-mentioned method.

Table 1 shows the average fiber diameters of the non-woven fabrics used in Examples and Comparative Examples measured according to the method described above. Regarding Examples (for example, Examples 1 and 2) and Comparative Examples in which the same raw material fibers are used, the average fiber diameter may be slightly different in Table 1, but this is slightly different from the measured value of the measurement. Due to the deviation. Table 1 shows the fineness of the fibers as well as the average fiber diameter. In Examples and Comparative Examples using the laminated web, Table 1 shows the fineness of the fibers constituting each layer.
In addition, the maximum elongation of the non-woven fabrics of Examples and Comparative Examples was measured by the method described above.
Further, the fine fiber ratio was measured on both sides of the non-woven fabric by the method described above.
The measurement results are shown in Table 1. In Table 1, of the first surface and the second surface of the non-woven fabric, the fine fiber ratio and the fine fiber ratio of the surface having a fine fiber ratio of 20% or more and a substantially orthogonal type fused portion ratio of 35% or more are shown in Table 1. Approximately orthogonal type fusion part ratio is shown. Further, Table 1 shows the measurement results of the first surface and the second surface of the non-woven fabric, whichever has the higher ratio of the substantially orthogonal fused portion, for the comparative example.

As shown in Table 1, the non-woven fabric of each example had a fine fiber ratio of 20% or more on at least one surface and a substantially orthogonal type fused portion ratio of 35% or more. Although such a non-woven fabric contains fine fibers having a fiber diameter of 15 μm or less, the maximum elongation is lower than that of the comparative example. From the results in Table 1, it can be seen that the non-woven fabric in each example is less likely to stretch and less likely to shrink in width due to the stretching than the non-woven fabric in the comparative example.

According to the present invention, it is possible to provide a non-woven fabric in which width shrinkage is suppressed while containing fibers having a small fiber diameter, a non-woven fabric product and an absorbent article provided with the non-woven fabric, and a method for producing the non-woven fabric product.

Claims (20)

1. A non-woven fabric having a first surface and a second surface located on the opposite side of the first surface.
   As a heat-sealed portion containing thermoplastic fibers and the intersections of the fibers are heat-sealed, a substantially orthogonal fusion portion in which the fibers intersect at an angle of 70 ° or more and 90 ° or less is formed. Have and
   Contains fine fibers that are fibers with a fiber diameter of 15 μm or less.
   At least one of the first surface and the second surface has a fine fiber ratio of 20% or more when the observation region of 500 μm × 400 μm is observed at a magnification of 200 times, and the heat existing in the observation region. A non-woven fabric having a substantially orthogonal type fused portion ratio of 35% or more, which is a ratio of the number of the substantially orthogonal type fused portions to the number of fused portions.
2. The non-woven fabric according to claim 1, wherein the fine fiber ratio is 25% or more, preferably 30% or more.
3. The non-woven fabric according to claim 1 or 2, wherein the fine fiber ratio is 100% or less.
4. The non-woven fabric according to any one of claims 1 to 3, wherein the substantially orthogonal fused portion ratio is 50% or more, preferably 52% or more.
5. The non-woven fabric according to any one of claims 1 to 4, wherein the substantially orthogonal fused portion ratio is 80% or less, preferably 70% or less.
6. The non-woven fabric according to any one of claims 1 to 5, wherein the total number of the substantially orthogonal fused portions existing in the five observation regions is 15 or more, preferably 20 or more.
7. The non-woven fabric according to any one of claims 1 to 6, wherein the total number of the substantially orthogonal fused portions existing in the five observation regions is 50 or less, preferably 40 or less.
8. The non-woven fabric according to any one of claims 1 to 7, which has a basis weight of 30 g / m ² or less, preferably 26 g / m ^{2 or less.}
9. The non-woven fabric according to any one of claims 1 to 8, which has a basis weight of 5 g / m ² or more, preferably 8 g / m ^{2 or more.}
10. The non-woven fabric according to any one of claims 1 to 9, wherein the maximum elongation is 20% or more, preferably 25% or more.
11. The non-woven fabric according to any one of claims 1 to 10, wherein the maximum elongation is 60% or less, preferably 55% or less.
12. The non-woven fabric according to any one of claims 1 to 11, wherein the thermoplastic fiber is a short fiber.
13. A non-woven fabric product comprising the non-woven fabric according to any one of claims 1 to 12.
    The first surface has a higher ratio of the substantially orthogonal fused portion than the second surface.
    A non-woven fabric product in which the first surface is arranged so as to form the surface of the non-woven fabric product.
14. An absorbent article comprising the non-woven fabric according to any one of claims 1 to 12 as a constituent member.
15. It includes a front surface sheet, a back surface sheet, and an absorber arranged between the front surface sheet and the back surface sheet.
    The absorbent article according to claim 14, wherein the non-woven fabric is provided as either one or both of the front surface sheet and the back surface sheet.
16. The absorbent article according to claim 15, wherein the non-woven fabric is provided as the back sheet.
17. The absorbent article according to claim 16, wherein the back surface sheet is made of a laminated sheet of a liquid impervious sheet and the non-woven fabric.
18. A method for producing a nonwoven fabric product, comprising a nonwoven fabric having a first surface and a second surface located on the opposite side of the first surface.
    The non-woven fabric contains thermoplastic fibers, and the intersections of the fibers are fused as a heat-sealed portion in a state where the fibers are fused at an angle of 70 ° or more and 90 ° or less. It has a wearing part and
    Contains fine fibers that are fibers with a fiber diameter of 15 μm or less.
    At least one of the first surface and the second surface has a fine fiber ratio of 20% or more when the observation region of 500 μm × 400 μm is observed at a magnification of 200 times, and the heat existing in the observation region. The ratio of the substantially orthogonal fused portions, which is the ratio of the number of the substantially orthogonal fused portions to the number of fused portions, is 35% or more.
    A method for producing a non-woven fabric product, comprising a step of superimposing the non-woven fabric on the non-woven fabric so that the surface having the substantially orthogonal fusion portion ratio is opposed to the other constituent members.
19. The method for producing a nonwoven fabric product according to claim 18, wherein the substantially orthogonal fused portion ratio is 50% or more, preferably 52% or more on at least one of the first surface and the second surface.
20. The method for producing a non-woven fabric product according to claim 18 or 19, wherein the non-woven fabric product is an absorbent article.

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