STRETCH SHEET FOR ABSORBENT ARTICLE AND PROCESS THEREIN

Abstract

The present invention provides a stretchable sheet (1) for an absorbent article in which a plurality of elastic filaments (4), arranged to stretch in one direction without crossing each other, are joined to stretchable sheet materials (2 and 3) along their entire length in a substantially unstretched state. Some or all of the plurality of elastic filaments (4) are narrowed filaments (40) having at least one narrow portion (40k) in a cross-section orthogonal to a longitudinal direction (Y).It is preferable that the cross-section of each narrowed filament (40) that is orthogonal to the longitudinal direction (Y) has a shape in which a plurality of circles are connected together in a state of partial overlap, and it is preferable that the center-to-center distance between adjacent circles be shorter than the sum of the radius of a first circle and the radius of a second circle, and longer than the shorter radius of the radius of the first circle and the radius of the second circle.

Description

Description Title of the invention: STRETCH SHEET FOR ABSORBENT ARTICLE AND METHOD FOR PRODUCING IT

[0001] Technical field The present invention relates to a stretchable sheet for an absorbent article and a manufacturing process of stretchable sheet.

[0002] State of the art As a stretchable sheet, the applicant of the present invention has proposed a stretchable sheet in which a plurality of elastic filaments are arranged in such a way as to extend in one direction without crossing are joined to a material of sheet stretchable along its entire length in a substantially unstretched state (see bed- (patent 1). The stretchable sheet disclosed in the literature patent 1 is produced by performing the steps of spinning a molten elastic resin from a plurality of spinning nozzles to obtain a plurality of elastic filaments in a molten or softened state, to grasp and pull the plurality of elastic filaments at a speed predetermined and to bond by fusion the elastic filaments to a sheet material before that the elastic filaments solidify,

[0003] — Furthermore, with regard to a method for producing such a stretchable sheet, the The applicant for the present invention has proposed a method for producing a sheet stretchable using a spinning head which includes a portion of arrangement in staggered arrangement in which several spinning nozzles are arranged in a pattern called staggered (see patent literature 2). Patent literature 2 indicates that a spinning head is used in which the spinning nozzles are arranged in a staggered pattern, or more specifically, a plurality of rows of nozzles in each of which a A plurality of spinning nozzles are arranged at predetermined intervals in a direction are arranged in a direction that is orthogonal to the direction arrangement of the spinning nozzles, and the spinning nozzles of the adjacent rows in these orthogonal directions are offset from each other.

[0004] — List of citations Literature patent Literature patent 1 JP 2008-179128A Literature patent 2 JP 2017-61064A

[0005] Summary of the invention The present invention proposes a stretchable sheet in which a plurality of elastic filaments that are arranged in such a way as to extend in one direction without crosses are joined to a sheet material that stretches along their entire length in a substantially unstretched state. In exemplary embodiments, the stretchable sheet is a stretchable sheet for an absorbent article. In exemplary embodiments, some or all of the elastic filaments are shrunken filaments having at least one narrow portion in a cross-section that is orthogonal to a direction of extension in which the elastic filaments stretch. Furthermore, the present invention proposes a method for producing a stretchable sheet, the method comprising a fusion bonding step consisting of bringing a plurality of elastic filaments in a molten or softened state, dispensed from a plurality of spinning nozzles, into contact with a sheet of raw material before the elastic filaments solidify, thereby fusion-bonding the elastic filaments to the sheet of raw material. In exemplary embodiments, the stretchable sheet is a stretchable sheet for an absorbent article. In exemplary embodiments, in the fusion bonding step, a plurality of rows of nozzles, in each of which a plurality of spinning nozzles are arranged at regular intervals in a first direction, are formed in a second direction that is orthogonal to the first direction.In some embodiments, a spinning head is used in which the positions of the spinning nozzles in adjacent nozzle rows in the second direction are offset from each other in the first direction. In some embodiments, a receiving means is used to receive elastic filaments spun from the spinning nozzles of the spinning head. In some embodiments, the elastic filaments, in a molten or softened state, spun from the spinning nozzles, are received at a receiving speed of 40 m / min to 200 m / min. Brief description of the drawings [fig.1] Figure 1(a) is a perspective view showing a stretched state of a stretchable sheet according to a preferred embodiment of the present invention, and Figure 1(b) is a perspective view schematically showing a state in which the sheet is disjointed into two sheet materials and a plurality of elastic filaments. [fig.2] Figure 2 is a cross-sectional view schematically showing a cross-section of the stretchable sheet of the present embodiment (cross-sectional view of a portion corresponding to a cross-section AA of the stretchable sheet shown in Fig. 1). [fig.3] Figure 3(a) is a front view schematically showing a single filament in Fig. 2. Figure 3(b) is a front view schematically showing a narrowed filament with a narrow portion shown in Fig. 2, and Figure 3(c) is a front view schematically showing a narrowed filament with two narrow portions shown in Fig. 2. [Fig. 4] Figure 4 is a perspective view schematically showing relevant portions of a spinning apparatus used to perform a melt spinning step in a stretchable sheet production process of the present embodiment. [Fig. 5] Figure 5 is a perspective view schematically showing a spinning head of the spinning apparatus shown in Figure 4, with one end surface (nozzle mounting surface) of the spinning head facing upwards. [Fig. 6] Figure 6 is a plan view schematically showing the lower end surface of the spinning head shown in Figure 5. [fig.7] Figure 7 is a perspective view schematically showing relevant portions of a traction device which is used to carry out a step conferring stretchability in the production process of the stretchable sheet in the present embodiment. Description of the implementation methods The stretchable sheet described above is used for various purposes, and the need to adjust the tension may arise depending on the application. If the tension in the stretchable sheet needs to be improved, for example, by increasing the number of elastic filaments bonded to the sheet material, the area of ​​regions in the sheet where the elastic filaments are not present decreases. Since the stretchable sheet described above is obtained by melt-bonding elastic filaments, produced by pulling a molten or softened elastic resin onto the sheet material, if the area of ​​regions where the elastic filaments are not bonded decreases, the thickness of the stretchable sheet also decreases. Therefore, the tactile feel can be improved. If, for example, one attempts to improve the tensile strength of a stretchable sheet by increasing the diameter of the elastic filaments, the contact area between the elastic filaments and the sheet material increases, and, for example, a hole or similar defect may be formed in the sheet material during the stretching process. Consequently, there is a possibility of improving the appearance. The inventors of the present invention have observed that, where stress needs to be improved, a stretchable sheet in which stress can be increased while maintaining a favorable tactile feel and without altering the appearance can be obtained by using elastic filaments having at least one narrow portion in a cross-section orthogonal to the direction of extension in which the elastic filaments stretch. Furthermore, the inventors of the present invention have discovered that elastic filaments having such narrow portions can be efficiently obtained by arranging spinning nozzles in a pattern... staggered and by adjusting the reception speed of the elastic filament within a predetermined speed range. In patent literature 1 and patent literature 2, there is no description concerning the effect whereby a stretchable sheet comprises such elastic filaments having a narrow portion and the spinning speed of the resin and the reception speed of the elastic filaments are fixed within predetermined speed ranges. Therefore, the present invention relates to a stretchable sheet that can eliminate the above-described disadvantages of the related art, and a method for producing the stretchable sheet. The present invention will be described below based on a preferred embodiment thereof, with reference to the drawings. Figures 1(a), 1(b), and 2 show a stretchable sheet 1 according to a preferred embodiment of the present invention, and Figures 3(a) to 3(c) show elastic filaments 4 included in the stretchable sheet 1. The stretchable sheet is preferably a stretchable sheet for an absorbent article. As shown in Figures 1(a), 1(b), and 2, the stretchable sheet 1 has a configuration in which several filamentary elastic filaments 4 are joined to two sheet materials 2 and 3, and several elastic filaments 4 are arranged so as to extend in one direction without crossing each other. Each of the plurality of elastic filaments 4 is sandwiched between the two sheet materials 2 and 3 and, in this state, joined to the two sheet materials 2 and 3 along the entire length in one direction (longitudinal direction indicated by a reference symbol Y) of the stretchable sheet 1 in a substantially unstretched state. As used here, "elastic" means the property of being able to be stretched and contract once released from the stretching force, and the "substantially unstretched state" means a state of the elastic filaments in which the elastic filaments do not contract when the external force is removed. The stretchable sheet 1 achieves its stretchability through the elasticity of the elastic filaments 4. When the stretchable sheet 1 is stretched in the same direction as the stretching direction of the elastic filaments 4, the elastic filaments 4 and the sheet materials 2 and 3 are stretched. Then, when the stretching of the stretchable sheet 1 is reversed, the elastic filaments 4 contract, and in accordance with this contraction, the sheet materials 2 and 3 return to their pre-stretched state. Since no other elastic filaments bound to the elastic filaments 4 while extending orthogonally to them are present in the stretchable sheet 1, when the stretchable sheet 1 is stretched in the same direction as the stretching direction of the elastic filaments 4, the stretchable sheet 1 is stretched substantially without causing what is called a 'width shrinkage', namely a shrinkage in the direction that is perpendicular to the stretching direction. Depending on the specific use, the surface mass of the entire stretchable sheet 1 is preferably 10 g / m² or more, and preferably 20 g / m² or more, preferably 80 g / m² or less, and 70 g / m² or less, and more particularly from 10 g / m² to 80 g / m² and from 20 g / m² to 70 g / m², From the point of view of obtaining a favorable tactile feel, the thickness of the stretchable sheet 1 is 0.32 mm or more, more preferably 0.36 mm or more, and even more preferably 0.39 mm or more, is preferably 0.5 mm or less, and even more preferably 0.4 mm or less, and specifically, is preferably from 0.32 mm to 0.5 mm, more preferably from 0.36 mm to 0.5 mm, and even more preferably from 0.39 mm to 0.4 mm. A measurement of the thickness of the stretchable sheet 1 is carried out as follows. The thickness of a sheet to be measured can be measured by placing the sheet to be measured between flat plates under a load of 0.5 cN / em and measuring the distance between the flat plates.From the point of view of preventing the formation of a hole or similar when imparting stretchability to a composite sheet 1 during a stretch-impairing step to be described later, the peel strength of the stretchable sheet 1 (peel strength of each of the sheet materials 2 and 3 with respect to the elastic filaments 4) is preferably 5 cN / filament or more, and more preferably 10 cN / filament or more, and preferably 30 cN / filament, more preferably 20 cN / filament or less, and even more preferably 18 cN / filament or less, and specifically, is preferably from 5 cN / filament to 30 cN / filament, more preferably from 10 cN / filament to 20 cN / filament, and even more preferably from 10 cN / filament to 18 cN / filament. The peel strength of the stretchable sheet 1 is measured as follows.Each of the two sheet materials 2 and 3 of the stretchable sheet 1, which is the sheet to be measured, is held in a mandrel, and the sheet material 2 of the two sheets is peeled apart at a speed of 300 mm / min. The peel resistance of sheet 1 can be measured by measuring the maximum load at that moment. From the perspective of achieving sufficiently stretchable characteristics, it is preferable that the ratio (50% return load / 50% stretch load) of the load (hereinafter also referred to as the "50% return load") of the stretchable sheet 1 when stretched 100% in the extension direction of the elastic filaments 4 and then reversed 50% from this state to the load (hereinafter also referred to as the "50% stretch load") of the stretchable sheet 1 when stretched 50% in the extension direction of the elastic filaments 4, be 45% or more, and preferably 50% or more, and preferably 100% or less. In particular, the ratio described above is preferably 45% to 100%, and more preferably 50% to 100%. From the same perspective, the 50% return load is preferably 80 cN / 50 mm or more, and even more preferably 120 cN / 50 mm or more, is preferably 150 cN / 50 mm or less, and more preferably 135 cN / 50 mm or less, and specifically 80 cN / 50 mm to 150 cN / 50 mm, and more preferably 120 cN / 50 mm to 135 cN / 50 mm. From the same point of view, the 50% stretch load is preferably 80 cN / 50 mm or more, more preferably 120 cN / 50 mm or more, and even more preferably 245 cN / 50 mm or more, is preferably 600 cN / 50 mm or less, more preferably 300 cN / 50 mm or less and even more preferably 250 cN / 50 mm or less and, preferably, from 80 cN / 50 mm to 600 cN / 50 mm, more preferably from 120 cN / 50 mm to 300 cN / 50 mm and even more preferably from 245 cN / 50 mm to 250 cN / 50 mm. Method for measuring a 50% return load and a 50% stretch load: A 100% elongation cycle test of a stretchable sheet is performed using a tensile testing apparatus (AG-IS manufactured by Shimadzu Corporation). Specifically, a sample of the stretchable sheet intended for use in the 100% elongation cycle test is first prepared and fixed to the tensile testing apparatus so that the direction of tension coincides with the direction of extension in which the elastic filaments stretch. At this point, the distance between the mandrels is set at 150 mm. The sample is stretched 150 mm (the distance between the mandrels becomes 300 mm in total) at a speed of 300 mm / min in the stretch / contraction direction of the sample, and immediately afterward, the sample is returned to its original length at a speed of 300 mm / min. Note that the initial length between the mandrels can be changed depending on the length of the sample being tested.In the 100% elongation cycle test, 100% elongation refers to a state in which the sample is stretched to twice its initial length. During the stretching of the sample to 100% elongation, the tensile force at the point of 50% elongation—that is, the tensile force at the point of 1.5 times its initial length—is called the "50% stretch load." During the return of the sample to its initial length after stretching it to 100% elongation, the tensile force at the point of 50% elongation is called the "50% return load." If a stretchable sheet incorporated into an absorbent article, such as a diaper, is to be measured, the adhesive used in the absorbent article is dissolved in an organic solvent, and the stretchable sheet is removed. An organic solvent that does not dissolve an elastic material is used as the solvent at this stage. The removed stretchable sheet is then dried, and subsequently, it is measured according to the measurement procedure described above. For the measurement of other properties described in this specification, the removed stretchable sheet, as described above, is also measured after it has been dried. The two sheet materials 2 and 3 constituting the stretchable sheet 1 are stretchable. Both sheet materials 2 and 3 contain essentially inelastic fibers, or typically contain inelastic fibers, and are essentially inelastic, or are generally inelastic. Each of the sheet materials 2 and 3 is stretchable in the same direction as the extension direction (longitudinal direction indicated by the reference symbol Y in Figure 1) of the elastic filaments 4.As used here, "stretchable" encompasses (a) a case where the constituent fibers themselves of sheet materials 2 and 3 are stretchable; and (b) a case where, even if the constituent fibers themselves are not stretchable, a nonwoven fabric as a whole is stretchable because the fibers bonded to each other are separated from each other, a three-dimensional structure formed of several fibers by bonding or similar means the fibers change structurally, the constituent fibers tear, or because of slack in the fibers being received. Each of the plurality of elastic filaments 4 constituting the stretchable sheet 1 extends substantially continuously along the entire length of the stretchable sheet 1, and typically extends continuously along its entire length as in the embodiment shown in Figure 1. Each elastic filament 4 contains an elastic resin. The plurality of elastic filaments 4 are arranged so as to extend in a direction without crossing each other in the direction orthogonal to the direction of extension. As long as the elastic filaments 4 do not cross, they can extend linearly or can extend in a serpentine pattern. The direction of extension, which is the direction in which the elastic filaments extend, generally coincides with the longitudinal direction Y, and the direction orthogonal to the direction of extension generally coincides with a width direction X. Each elastic filament 4 is joined to the sheet materials 2 and 3 in a substantially unstretched state. Because the elastic filaments 4 are joined to the sheet materials 2 and 3 in an unstretched state, relaxation (creep) of the stretchable sheet 1 due to stretching does not occur, and the stretchable sheet 1 has the advantage of being less susceptible to deterioration in terms of stretchability. Furthermore, the stretchable sheet 1 has the advantage of being able to stretch to the stretchable length of the sheet materials 2 and 3 or to the maximum elongation of the elastic filaments 4. Preferably, the elastic filaments 4 are each fusion-bonded to the stretchable sheet materials 2 and 3 along their entire length in a substantially unstretched state.Here, the expression "fusion bonded" does not mean that the elastic filaments 4 are joined to the sheet materials 2 and 3 by a third component such as an adhesive, but rather means that the elastic filaments 4 are joined to the sheet materials 2 and 3 as a result of the fusion of at least one of the resin constituting the elastic filaments 4 and the resin constituting the sheet materials 2 and 3. From the perspective of achieving a favorable tactile sensation, the end-to-end distance P (see Fig. 2) between adjacent elastic filaments 4 in the width direction X is preferably 0.4 mm or more, and more preferably 0.6 mm or more, preferably 1.2 mm or less, more preferably 1 mm or less, and even more preferably 0.4 to 1.2 mm or less, more preferably 0.6 mm to 1 mm, and even more preferably 0.6 to 0.8 mm. The end-to-end distance can be fixed between all the elastic elements or, as shown in Figure 2, the end-to-end distance between one pair of elastic filaments can be different from that between another pair of elastic filaments.In the case where the end-to-end distance P is not fixed, it is preferable that an average value of the end-to-end distances between the elastic filaments be within the preferred range described above, and it is even more preferable that the end-to-end distances between all the elastic filaments be within the preferred range described above. Method for measuring the end-to-end distance P between adjacent elastic filaments: To measure the end-to-end distance P between four elastic filaments that are adjacent to each other, a cut surface from a sample of the elastic sheet, cut in the width direction, is magnified under a microscope. The measurement is taken at 100 random points, and the average value thus obtained is used as the average end-to-end distance. The measurement is performed by cutting a plurality of cut surfaces at different positions in the longitudinal direction and measuring the end-to-end distance between adjacent elastic filaments in each of the plurality of cut surfaces. Some of the elastic filaments 4 included in the stretchable sheet 1 are narrowed filaments 40, each having at least one narrow portion 40k in a cross-section (hereafter also referred to as the "cross-section in the width direction") that is orthogonal to the extension direction (longitudinal direction Y), in which the elastic filaments extend. The elastic filaments 4 comprise simple filaments 41, each having no narrow portion 40k, and narrowed filaments 40, each having at least one narrow portion 40k. Here, a filament having a narrow portion in a cross-section that is orthogonal to the extension direction means that when visualizing the cross-section that is orthogonal to the extension direction of the filament, there are a pair of indented portions that are indented from a peripheral surface of the filament towards the inner side of the cross-section.For example, having two narrow portions means that there are two pairs of these recessed portions. More specifically, in the embodiment shown in Figure 2, the narrowed filaments 40 comprise filaments 42 each having one narrow portion 40k and a filament 43 having two. narrow portions 40k. Note that all the elastic filaments 4 included in the stretchable sheet for an absorbent article of the present invention can be narrowed filaments 40 each having at least one narrow portion. The single filaments 41 are obtained by drawing molten resin, poured from the spinning nozzles 12, which will be described later, along a spinning line. As shown in Figure 3(a), the diameter D of a single filament 41 is not particularly limited, but considering the balance between the texture of the stretchable sheet 1 and the productivity of the elastic filaments 4, the diameter D is preferably 40 µm or more, and more preferably 80 µm or more, preferably 200 µm or less, and more preferably 180 µm or less, and is from 40 µm to 200 µm and more preferably from 80 µm to 180 µm. The diameter of the single filaments 41 depends on the diameter of the spinning nozzles 12, which will be described later. The shrunken filaments 40 are obtained, for example, by at least two single filaments shed from two or more adjacent spinning nozzles 12, which bind together during drawing. A cross-section in the width direction of the shrunken filaments 40 has a shape in which a plurality of circles are linked together in the width direction X in a state of partial overlap. Specifically, a cross-section in the width direction of filaments 42 having a narrow portion has a shape in which, as shown in Figure 3(b), two circles c1 and c2 are linked to each other in the width direction X in a state of partial overlap. A cross-section in the width direction of filaments 43 having two narrow portions has a shape in which, as shown in Figure 3(c), three circles c3, c4, and c5 are linked together in the width direction X in a state of partial overlap.The overlapping portions of the circles that are connected together are the portions that are located at the level of connecting portions between adjacent circles and enclosed by circular arcs as shown in dotted lines in figures 3(b) and 3(c). By bringing a cross-section in the width direction to a shape in which several circles are connected together in a state of partial overlap—that is, by providing at least a narrow portion 40k in the cross-section in the width direction—it is possible to improve the stress in the stretch film 1 while eliminating a reduction in the end-to-end distance between adjacent elastic threads 4, unlike a case where the number of single filaments 41 is increased, for example. That is, it is possible to improve the stress in the stretch film 1 while obtaining a favorable tactile feel by maintaining a large thickness of the stretch film 1. Compared to a case where the cross-sectional area of ​​single filaments 41 is increased by increasing their diameter, an increase in the contact area between the materials of Sheets 2 and 3 and the elastic filaments 4 can be eliminated. That is, by improving the stress in the stretchable sheet 1 by increasing the cross-sectional area of ​​the elastic filaments 4, it is possible to maintain a favorable appearance by eliminating the formation of a hole or similar feature in the stretching step, which will be described later. As described above, with the stretchable sheet of the present embodiment, it is possible to improve the stress produced by the elastic filaments 4 while obtaining a favorable tactile feel for the stretchable sheet and maintaining its favorable appearance. As shown in Figure 1(b), a narrow portion 40k of a shrunken filament 40 extends in the extension direction (longitudinal direction Y) of the elastic filaments 4. Thanks to the shrunken filaments 40 of the stretchable sheet 1, whose narrow portions 40k extend in the extension direction of the elastic filaments 4, it is possible to further improve the stress produced by the elastic filaments 4 while obtaining a favorable tactile feel of the sheet and maintaining a favorable appearance of it. From the point of view of achieving a favorable tactile sensation and maintaining a favorable appearance, it is preferable that in an external form of a cross-section in the width direction of each narrowed filament 40, the end-to-end distance P1 between adjacent circles be less than the sum of the radius of the first circle and the radius of the second circle, and greater than the shorter radius of the first circle and the radius of the second circle. In particular, as shown in Figure 3(b), in an external form of a cross-section in the width direction of a filament 42 having a narrow portion, it is preferable that the end-to-end distance PI between adjacent circles c1 and c2 be less than the sum (r1+r2) of the radius r1 of the first circle c1 and the radius r2 of the second circle c2, and greater than the shorter radius (e.g.the radius rl of the first circle c1) chosen from the radius rl of the first circle c1 and the radius r2 of the second circle c2. Preferably, the radius rl of circle c1 and the radius r2 of circle c2 are radii in a direction that is the same as the width direction X. Similarly, as shown in Figure 3(c), in a cross-section in the width direction of a filament 43 having two narrow portions, it is preferable that the end-to-end distance P2 between adjacent circles c3 and c4 be less than the sum (r3+r4) of the radius r3 of the first circle c3 and the radius r4 of the second circle c4, and greater than the shorter radius (e.g., the radius r3 of the first circle c3) chosen from the radius r3 of the first circle c3 and the radius r4 of the second circle c4.Furthermore, it is preferable that the end-to-end distance P3 between adjacent circles c4 and c5 be less than the sum (r4+r5) of the radius r4 of the first circle c4 and the radius r5 of the second circle c5, and greater than the shortest radius (e.g., the radius . r4 of the first circle c4) chosen from the radius r4 of the first circle c4 and the radius r5 of the second circle c5. It is preferable that the radius r3 of circle c3 and the radius r5 of circle c5 be radii in a direction that is the same direction as the width direction, and it is preferable that the radius r4 of circle c4 be a radius in a direction that is the same direction as the thickness Z direction. In a cross-section in the width direction (cross-section that is orthogonal to the extension direction) of a narrowed filament 40, the maximum length of the narrowed filament in the width direction X is preferably 100 jm or more, and preferably 200 µm or more, is preferably 800 µm or less, more preferably 400 µm or less, and even more preferably 500 µm or less, and especially preferred 270 jm or less and, specifically, is preferably from 100 µm to 800 µm, more preferably from 100 µm to 400 µm, even more preferably from 200 jm to 500 µm, and even more preferably from 200 µm to 270 µm. The maximum length of the filament shrunk in the width direction X is the maximum length in the width direction of a cross-section in the width direction of the shrunk filament and can be measured according to the following method. Method for measuring the maximum length of a filament shrunk in the width direction: To measure the maximum length of the filament shrunk 40 in the width direction X, a cut surface of a sample of a stretchable sheet, when cut in the width direction, is magnified under a microscope. The measurement is taken at 30 random points for each shrunk filament, the 30 random points being located at different positions in the longitudinal direction, and their average value is used as the maximum length of the filament shrunk 40 in the width direction. From the perspective of achieving a favorable tactile sensation, as shown in Figure 3(b), in a filament 42 having a narrow portion, the ratio ((L2 / L1)x100) of the length L2 in the thickness direction Z to the length LI in the width direction X is preferably 10% or more, and more preferably 30% or more, preferably 60% or less, and more preferably 50% or less, and specifically, preferably from 10% to 60%, and more preferably from 30% to 50%. Note that the length LI in the width direction X of a filament 42 having a narrow portion means the maximum length in the width direction X, and the length L2 in the thickness direction Z of a filament 42 having a narrow portion means the maximum length, i.e., the diameter in the thickness direction Z. From the same point of view, in a filament 42 having a narrow portion, the ratio ((L3 / L2)x100) of the minimum length L3 of the narrow portion 40k in the thickness direction Z on the length L2 in the thickness direction Z is, preferably, 5% or more and, more preferably, 10% or more, is preferably 50% or less, and more preferably 30% or less and, specifically, is preferably 5% to 50%, and more preferably 10% to 30%. From the same perspective, the maximum length LI in the width direction of a filament 42 having a narrow portion is preferably 100 µm or more, and more preferably 200 µm or more, is preferably 400 µm or less, and more preferably 300 µm or less, and, specifically, is from 100 µm to 400 µm, and more preferably from 200 µm to 300 µm. From the same perspective, the maximum length L2 in the thickness direction of a narrowed filament 40 is preferably 80 µm or more, and preferably 100 µm or more, is preferably 200 µm or less, and more preferably 180 µm or less, and specifically, is preferably from 80 µm to 200 µm, and more preferably from 100 µm to 180 µm. From the same perspective, the minimum length L3 in the thickness direction Z of a narrow portion 40k of a narrowed filament 40 is preferably 5 µm or more, and more preferably 10 µm or more, is preferably 60 µm or less, and more preferably 50 µm or less, and specifically, is preferably from 5 µm to 60 µm, and more preferably from 10 µm to 50 µm. From the perspective of achieving a favorable tactile sensation, as shown in Fig. 3(c), in a filament 43 having two narrow portions, the ratio ((L5 / L4)x100) of the length LS in the thickness direction Z to the length LA in the width direction X is preferably 5% or more, and more preferably 10% or more, is preferably 60% or less, and more preferably 50% or less and, specifically, is 5% to 60%, and more preferably 10% to 50%.Note that the length L4 in the width direction X of a filament 43 having two narrow portions means the maximum length in the width direction X, and the length LS in the thickness direction Z of a filament 43 having two narrow portions means the maximum length in the thickness direction Z. From the same point of view, in a filament 43 having two narrow portions, the ratio ((L6 / L5)x100) of the minimum length L6 of the narrow portion 40k in the thickness direction Z to the length LS in the thickness direction Z is preferably 5% or more, and more preferably 10% or more, is preferably 50% or less, and more preferably 30% or less and, specifically, is preferably 5% to 50%, and more preferably 10% to 30%. From the same point of view, the maximum length LA in the width direction of a filament 43 having two narrow portions is preferably 200 µm or more, and more preferably 300 µm or more, is preferably 600 µm or less, and more preferably 500 µm or less, and, specifically, is preferably from 200 µm to 600 µm, and more preferably from 300 µm to 500 µm. From the same point of view, the maximum length LS in the thickness direction of a filament 43 having two narrow portions is preferably 80 µm or more, and more preferably 100 µm or more, is preferably 200 µm or less, and more preferably 180 µm or less, and specifically is preferably from 80 µm to 200 µm, and more preferably from 100 µm to 180 µm.From the same point of view, the minimum length L6 in the thickness direction Z of a narrow portion of 40k of a filament 43 having two narrow portions is preferably 5 µm or more, and more preferably 10 µm or more, is preferably 60 µm or less, and more preferably 50 µm or less, and, specifically, from 5 µm to 60 µm, and more preferably from 10 µm to 50 µm. In the stretchable sheet 1, from the point of view of achieving a favorable tactile sensation and suppressing deterioration of appearance, the ratio ((number of shrunken filaments 40 / number of elastic filaments 4)x100) of the number of shrunken filaments 40 to the number of elastic filaments 4 is preferably 5% or more, more preferably 20% or more, and even more preferably 50% or more, is preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less and, specifically, is preferably 5% to 90%, more preferably 20% to 80% and even more preferably 50% to 70%.Note that the shrunken filaments 40 of the embodiment shown in Figure 2 and similar ones are each formed by a plurality of filaments adhering to each other immediately after being spun; however, for the purpose of counting the "number of elastic filaments", a filament which is incorporated into the stretchable sheet 1 while remaining in an immediate post-spinning state, a filament 42 having a narrow portion, and a filament 43 having two narrow portions are each considered as an "elastic filament". Similarly, in the case where the plurality of elastic filaments 4 includes a plurality of narrowed filaments 40, the ratio ((number of filaments 42 having a narrow portion / number of narrowed filaments 40)x100) of the number of filaments 42 having a narrow portion to the number of narrowed filaments 40 is preferably 50% or more, more preferably 60% or more, and even more preferably 90% or more, is preferably 100% or less, and specifically, is preferably from 50% to 100%, more preferably from 60% to 100%, and of an even more preferred method by 90% to 100%. Materials that form the stretch sheet 1 are described. For sheet materials 2 and 3, for example, nonwoven textiles such as air-permeable nonwovens, hot-laminated nonwovens, spun-laced nonwovens, spun-bonded nonwovens, and extruded-blown nonwovens can be used. These nonwovens can be composed of continuous filaments or staple fibers. Sheet materials 2 and 3 can be of the same type or different types. 'Sheet materials of the same type' means sheet materials that are identical with respect to the entire sheet material production process, the type of constituent fibers, the diameter and length of the constituent fibers, the thickness and surface mass of the sheet materials, etc.If the sheet materials differ with respect to at least one of them, the sheet materials are the "sheet materials of different types". The thickness of sheet materials 2 and 3 is preferably 0.05 mm or more, more preferably 0.1 mm or more, and even more preferably 0.15 mm or more, is preferably 5 mm or less, more preferably 1 mm or less, and even more preferably 0.5 mm or less, and, specifically, is preferably from 0.05 mm to 5 mm, more preferably from 0.1 mm to 1 mm, and even more preferably from 0.15 mm to 0.5 mm.To measure the thickness, a cross-section of the stretchable sheet 1 sandwiched between flat plates under a load of 0.5 cN / cm² is observed under a microscope at a magnification of 5 to 200 times. The average thickness is obtained in each field of view, and an average of the average thickness values ​​from three fields of view is obtained. The thickness of the entire sheet can be obtained by measuring the distance between the flat plates. Considering the texture, thickness, design quality, and similar factors, the surface mass of each of the sheet materials 2 and 3 is preferably 3 g / m² or more, and more preferably 5 g / m² or more, preferably 100 g / m² or less, and more particularly 30 g / m² or less, and specifically 3 g / m² to 100 g / m² or, more preferably, 5 g / m² to 30 g / m². . For example, inelastic fibers that are essentially inelastic can be used as constituent fibers of sheet 2 and 3 materials, and in this case, the sheet 2 and 3 materials can constitute layers of stretchable fibers composed mainly of inelastic fibers. These inelastic fibers include, for example, fibers and similar materials made of polyesters, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT), polyamides, and similar materials. The constituent fibers of sheet 2 and 3 materials can be staple fibers or fibers of Filaments can be hydrophilic or water-repellent. In addition, core-clad or side-by-side composite fibers, cleavable fibers, modified cross-section fibers, curled fibers, heat-shrinkable fibers, and similar fibers can also be used. These fibers can be used alone or in combination with two or more others. A preferred example of constituent fibers for sheet materials 2 and 3 is a fiber made of at least two components, including a lower-melting-point component and a higher-melting-point component. In this case, the constituent fibers are joined at fiber intersections by fusion bonding of at least the lower-melting-point component. Preferred core-cladding composite fibers made of at least two components, including a lower-melting-point component and a higher-melting-point component, are those in which the core is made of high-melting-point PET or PP and the cladding is made of lower-melting-point PET, PP, or PE. The use of these composite fibers strengthens the fusion bonding of the elastic filaments 4 with the sheet materials and reduces the risk of peeling, which is therefore preferable. The raw material for elastic filaments 4 is an elastic resin, such as a thermoplastic elastomer or rubber, for example. When a thermoplastic elastomer is used as the raw material, hot spinning with an extruder can be carried out as with ordinary thermoplastic resin, and the resulting elastic filaments can be easily bonded by thermal fusion and are therefore suitable for stretch film 1. Examples of styrene-based elastomers include SBS elastomers. (styrene-butadiene-styrene), SIS (styrene-isoprene-styrene), SEBS (styrene-ethylene-butadiene-styrene) and SEPS (styrene-ethylene-propylene-styrene), olefin-based elastomers (ethylene-based α-olefinic elastomers, and propylene elastomers, where ethylene, butene and octene and the like are copolymerized), polyester-based elastomers, polyurethane-based elastomers and the like, and these thermoplastic elastomers may be used alone or in a combination of two or more. A method for manufacturing the stretchable sheet 1 of the present invention is described with reference to Figures 4 to 7, using a method for manufacturing the stretchable sheet 1 of the embodiment described above by way of example. Figures 4 to 7 show a spinning apparatus 10 and a pulling apparatus which are used in the method for manufacturing the stretchable sheet 1 according to a preferred embodiment. As shown in Figure 4, the spinning apparatus 10 comprises a spinning head 11 which spins molten resin from spinning nozzles to obtain filaments Elastic filaments 4 in a molten or softened state, and a pair of gripper rollers 15 serving as a receiving means that receives a plurality of elastic filaments 4 dispensed from the spinning head 11. Typically, the pair of gripper rollers 15 are rollers having a smooth surface. This spinning apparatus 10 is an apparatus that spins filaments by what is called melt-extrusion, and includes, in addition to the spinning head 11, a molten material extruder (not shown) that melts chips of elastic resin and delivers the molten resin to the spinning head 11, and similar devices. The basic configuration of the spinning apparatus 10 is the same as that of a known melt-extrusion spinning apparatus.In addition, the spinning head 11 and the pair of pinch rollers 15 are electrically connected to a control unit, which is not shown, so that the control unit can adjust the resin discharge speed of the spinning head 11 and the reception speed of the pair of pinch rollers 15. As shown in Figure 5, the spinning head 11 comprises a bottom wall portion 11L that forms a lower end surface 1la of the head 11 and has a rectangular shape in plan view, and side wall portions 11S that are connected to the peripheral edges of the bottom wall portion 11L. An internal space of the spinning head 11, defined by these wall portions 11L and 11S, constitutes a storage portion 13 for molten resin supplied by the molten material extruder. Several spinning nozzles 12 are formed in the lower end surface 1la of the spinning head 1la, and the storage portion 13 of the spinning head 11 communicates with the outside via the various spinning nozzles 12. The material of the spinning head 11 can be similar to that of a known spinning head and is usually a metal. As shown in Figures 5 and 6, a staggered arrangement portion 12A in which the plurality of spinning nozzles 12 are arranged in a staggered pattern is provided in the lower end surface 1la, which serves as the nozzle installation surface, of the spinning head 11. In the staggered arrangement portion 12A, a plurality of nozzle rows (two, in the present arrangement) of nozzle rows 12L (in Figure 6, portions enclosed by dashed lines) in each of which several spinning nozzles 12 are arranged at given intervals in a first direction x1 of the lower end surface 1la are formed in a second direction y1 which is orthogonal to the first direction x1, namely in the direction of the width of the lower end surface 1la, and the positions of the spinning nozzles 12 in adjacent nozzle rows 12L, 12L are offset from each other by half a step in the first direction x1.By "staggered arrangement" we mean here not only a configuration in which the plurality of spinning nozzles 12 are arranged exactly as described above, but also a . configuration in which a slight involuntary displacement in the arrangement, such as a displacement that is unavoidable in production, occurs. The spinning nozzles 12 of the spinning head 11 have a circular shape in a plan view; however, in the present invention, the shape of the spinning nozzles in a plan view is not particularly limited and can be any shape, such as a polygonal shape. The diameter of the spinning nozzles 12, which have a circular shape in a plan view, influences the diameter and tensile strength of the elastic filaments 4. From this perspective, the diameter of the spinning nozzles 12 is preferably 0.1 mm or more, and more preferably 0.2 mm or more, 2 mm or less, and more preferably 0.6 mm or less. In the case where the diameter of the spinning nozzles 12 is within the range described above, the center-to-center distance (pitch pl) in the first direction x1 between adjacent spinning nozzles 12, 12 in each row of nozzles 12L of the staggered arrangement portion 12A is, from the point of view of developing a stress, preferably 0.5 mm or more, and more preferably 0.8 mm or more, is preferably 2 mm or less, and more preferably 1.5 mm or less, and, specifically, is preferably 0.5 to 2 mm, and more preferably 0.8 mm to 1.5 mm. In each of the rows of nozzles 12L, all the spinning nozzles 12 are arranged with an equal pitch. In the case where the diameter of the spinning nozzles 12 is within the range described above, the center-to-center distance (not p2) in the first direction x1 between any individual spinning nozzle 12 (hereafter referred to as particular nozzle 12) in one row of nozzles 12L of the adjacent 12L nozzle rows, 12L in the second direction y1 and a spinning nozzle 12 which is closest to this particular nozzle 12 in the other 12L nozzle row is, for the sake of tactile sensation, preferably 0.3 mm or more, and more preferably 0.5 mm or more, is preferably 1 mm or less, and more preferably 0.8 mm or less, and, specifically, is preferably 0.3 mm to 1 mm, and more preferably 0.5 mm to 0.8 mm. As shown in Figure 4, the production process for the stretchable sheet 1 of this embodiment includes a fusion bonding step consisting of receiving and drawing a plurality of elastic filaments 4 in a molten or softened state dispensed from the plurality of spinning nozzles 12 and fusion bonding the elastic filaments 4 to the sheets 2' and 3' of raw material from the sheet materials 2 and 3 before solidification of the elastic filaments 4. As shown in Fig. 7, the production process includes a stretchability-enhancing step which consists of subjecting a composite sheet ' obtained by the fusion bonding step to a treatment of traction. First, chips of an elastic resin, which is a raw material for the elastic filaments 4, are melted and kneaded using a molten material extruder, which is not shown, connected to the spinning head 11, and the elastic resin in the molten state is supplied to the storage portion 13 (see figure 5) of the spinning head 11. As shown in figure 4, the elastic resin thus supplied in the molten state is poured from the plurality of spinning nozzles 12, which are formed in the lower end surface of the spinning head 11, as elastic filaments 4 in a molten or softened state at a certain resin pouring rate V1.Since the plurality of spinning nozzles 12 are arranged in a staggered pattern as described above, the plurality of elastic filaments 4 spun from the respective spinning nozzles 12 extend while still retaining the shape of single elastic filaments 4 without crossing over, then some adjacent single elastic filaments 4 bond to each other on the way to the position in which the filaments 4 fuse with the raw material sheets 2" and 3' of the sheet materials 2 and 3. The adjacent single elastic filaments 4 are cooled to some extent on the upstream side, then bond to each other while being cooled on the downstream side. As shown in Figure 4, the plurality of elastic filaments 4 poured in the molten or softened state fuse with the sheets of raw material 2' and 3' which are unwound from the rolls of raw material at the same speed, and are intercalated between the two sheets of raw material 2' and 3" and received by the two pinching rollers 15, 15 at a certain receiving speed V2. The resin discharge rate V1 and the reception rate V2 of the elastic filaments 4 affect the diameter and tensile strength of the elastic filaments 4 as well as the bonding properties of the adjacent single elastic filaments 4. In order to efficiently produce the shrunken filaments 40 shown in Figures 2 and 3, it is naturally necessary to use the spinning head 11 described above, and in addition to this, it is effective to adjust the resin discharge rate V1 and the reception rate V2 of the elastic filaments 4. If the plurality of spinning nozzles 12 of the spinning head 11 are arranged linearly in a single row as in a conventional configuration, there are cases where adjacent single elastic filaments 4 bond to each other on the upstream side, i.e. in a highly molten state immediately after their discharge from the spinning nozzles, and form elastic filaments having a large diameter.In such cases, the contact area between the elastic filaments and the raw material sheets 2 and 3' increases, and therefore improvements can be made in the formation of a hole or similar. If only the spinning head 11 is used, in which the spinning nozzles 12 are located. Arranged in a staggered pattern, the elastic filaments 4 extend while still retaining the shape of the individual elastic filaments 4, and in many cases, no shrunken filament 40 is formed. However, as in the present case, by using the spinning head 11 in which the plurality of spinning nozzles 12 are arranged in a staggered pattern and by adjusting the receiving speed V2, in particular the resin discharge speed V1 and the receiving speed V2 to the following speeds, shrunken filaments 40 can be produced efficiently. From the perspective of the efficient production of the shrunken filaments 40, the ratio ((V2 / V1)x100) of the intake velocity V2 of the pinch roller pair 15, 15 to the resin discharge velocity V1 of the spinning head 11 is preferably 500% or more, and preferably 1000% or more, and 2500% or less, and more preferably 2000% or less. From the same perspective, the resin discharge velocity V1 of the spinning head 11 is preferably 5 m / min or more, and more preferably 8 m / min or more, preferably 30 m / min or less, and more preferably 25 m / min or less, and, specifically, from 5 m / min to 30 m / min, and more preferably from 8 m / min to 25 m / min.From the same point of view, the receiving speed V2 of the pair of pinch rollers 15, 15 is preferably 40 m / min or more, and more preferably 70 m / min or more, is preferably 200 m / min or less, and more preferably 180 m / min or less, and preferably from 40 m / min to 200 m / min, and more preferably from 70 m / min to 180 m / min. In order to efficiently produce filaments 42 having a narrow portion, the receiving speed V2 of the pair of pinch rollers 15, 15 is preferably 50 m / min or more, and more preferably 70 m / min or more, is preferably 180 m / min or less, and more preferably 150 m / min or less, and, specifically, from 50 m / min to 180 m / min, and more preferably from 70 m / min to 150 m / min. . The elastic filaments 4, in their molten or softened state, fuse with the raw material sheets 2' and 3' before solidifying, i.e., into a state that can be fusion-bonded. Therefore, the elastic filaments 4 are fusion-bonded to these raw material sheets 2' and 3' in a state where the elastic filaments 4 are intercalated between the raw material sheets 2' and 3'. That is, the elastic filaments 4, before solidification, are fusion-bonded to the raw material sheets 2' and 3' that are being conveyed, and thus the elastic filaments 4 are received and stretched. During the fusion bonding of the elastic filaments 4, no external heat is applied to the raw material sheets 2' and 3'.That is to say, only the heat of fusion caused by the elastic filaments 4 in the fusion-bondable state allows the elastic filaments 4 to be fusion-bonded to the two sheets of raw material 2' and 3'. Therefore, only the fibers present around . Elastic filaments 4, the constituent fibers of the two sheets of raw material 2' and 3', are fusion-bonded to the elastic filaments 4, while the fibers located further from the elastic filaments 4 are not fusion-bonded to them. Consequently, the heat applied to the two sheets of raw material 2' and 3' can be minimized, and therefore, if the two sheets of raw material 2' and 3' are, for example, nonwoven fabrics, a favorable texture intrinsic to nonwoven fabrics can be maintained. Thus, the resulting stretchable sheet 1 has a favorable texture. Until the spun elastic filaments 4, in their molten or softened state, fuse with the raw material sheets 2' and 3', the elastic filaments 4 are pulled, and molecules of the elastic filaments 4 are oriented in the direction of the pull. The diameter of the elastic filaments 4 decreases. To sufficiently pull the elastic filaments 4 and prevent their breakage, the temperature of the elastic filaments 4 can be adjusted by blowing air (hot or cold air) at a predetermined temperature onto the spun elastic filaments 4. The pull on the elastic filaments 4 is not limited to the pull (molten pull) of a resin composition (elastic resin), the resin composition forming the elastic filaments 4, in a molten state, and can also be the pull (softened pull) of the resin composition in a softened state during a cooling process. The temperature of the elastic filaments 4 when they fuse with the raw material sheets 2' and 3' is preferably 100°C or higher, and more preferably 120°C or higher, to ensure that the fibers are fusion-bonded. Furthermore, from the perspective of maintaining the shape of the elastic filaments 4 and thus obtaining a stretchable sheet 1 with favorable stretch characteristics, the temperature of the elastic filaments 4 at the time of fusion is preferably 180°C or lower, and more particularly 160°C or lower. Specifically, the temperature of the elastic filaments 4 at the time of fusion is preferably between 100°C and 180°C, and more preferably between 120°C and 160°C.The temperature at the time of fusion, that is, when the elastic filaments 4 are joined to the raw material sheets 2' and 3', can be measured using a modified polyethylene, modified polypropylene, or similar film having a melting point different from that of the resin composition constituting the elastic filaments 4 as the laminated base material to which the elastic filaments 4 are to be joined, and observing the state of the bond. At this time, if the elastic filaments 4 are fusion-bonded to the laminate base material, the bond temperature is equal to or greater than the melting point of the laminate base material. When the elastic filaments 4 fuse with (are joined to) the sheets of In raw material 2' and 3, the elastic filaments 4 are in a substantially unstretched state (a state in which the elastic filaments 4 do not contract when the external force is removed). In a state in which the elastic filaments 4 have been joined to the raw material sheets 2' and 3', it is preferable that at least some of the constituent fibers of the raw material sheets 2' and 3' be fusion-bonded to the elastic filaments 4, or, alternatively, that both the elastic filaments 4 and at least some of the constituent fibers of the raw material sheets 2' and 3' be fusion-bonded. This is because sufficient bond strength can be achieved. The stretchability characteristics of the resulting stretchable sheet 1 are affected by the density of the bond points at which the elastic filaments 4 are joined to the raw material sheets 2' and 3'.The stretchability characteristics can be adjusted not only according to the junction temperature and junction pressure, but can also be adjusted by tensile strength (see Figure 7) of the raw material sheets 2' and 3' through an elasticity-enhancing treatment, which will be described later. Through the fusion bonding of the constituent fibers of the raw material sheets 2' and 3' to the elastic filaments 4, the junction strength increases at each junction point. It is preferable to reduce the density of the junction points because the inhibition of stretchability by the raw material sheets 2' and 3' can be reduced, and a stretchable sheet 1 with sufficient junction strength can be obtained. When the plurality of elastic filaments 4 fuse with the raw material sheets 2' and 3', the elastic filaments 4 (single filaments 41 and shrunken filaments 40) are arranged in one direction without crossing each other. Then, in a state where the elastic filaments 4 have fused with the raw material sheets 2' and 3' and are sandwiched between the two raw material sheets 2 and 3', the three components are compressed by the pair of pinch rollers 15. The compression conditions affect the texture of the resulting stretchable sheet 1. If the compression force is high, the elastic filaments 4 are likely to bite into both raw material sheets 2' and 3'.For this reason, in light of the texture, it is sufficient that the compressive force applied by the pair of pinch rollers 15, 15 be such that the elastic filaments 4 are brought into contact with the two sheets of raw material 2' and 3', and an excessively high compressive force is not necessary. Thanks to the fusion bonding step described above, a composite sheet l' is obtained in which the elastic filaments 4 are intercalated and fixed between the two sheets of raw material 2' and 3'. Figure 7 illustrates one embodiment of the stretch-conferring step (elasticity-enhancing treatment). The stretch-conferring step is a step in which, after the elastic filaments 4 have been fusion-bonded to the The raw material sheets 2" and 3' are pulled in the direction of the extension of the elastic filaments 4, and through this step, extensibility is imparted to the raw material sheets 2' and 3', which initially have no extensibility. The object to be processed in the step conferring stretchability is the composite sheet l', which was obtained by the fusion bonding step shown in Figure 4 and in which the elastic filaments 4 are fusion bonded to the raw material sheets 2' and 3'. In the stretchability step illustrated in Figure 7, a traction device equipped with a pair of toothed rollers 17, 17 is used, in each of which teeth and grooves are alternately formed in the circumferential direction. This step is carried out by introducing the composite sheet l' between the two rollers 17, 17 and guiding the composite sheet l'. Thus, the composite sheet l' is pulled in the guiding direction, that is, in the direction of extension of the elastic filaments 4, and is thereby formed into a stretchable sheet 1 to be obtained.This traction device includes, as a means for enabling the passage of the composite sheet l' between the toothed rollers 17, 17, a pair of pinch rollers 16, 16 which are arranged on the upstream side of the toothed rollers 17 in the direction of travel of the composite sheet l' and a pair of pinch rollers 18, 18 which are arranged on the downstream side of the toothed rollers 17 in the direction of travel, and is configured so that the extent to which the composite sheet l' is pulled can be adjusted by an appropriate adjustment of the travel speed of the composite sheet l' using the rollers 16 and 18. The tensile device has a known lifting and lowering mechanism (not shown) that moves a pivot portion of one or both of the toothed rollers 17, 17 up and down, and is thus configured so that the distance between the two rollers 17, 17 can be adjusted. For example, the pair of toothed rollers 17, 17 are meshed with each other such that the teeth of the first roller 17 are inserted into the gaps between the teeth of the second roller 17 with clearance, and the teeth of the second roller 17 are inserted into the gaps between the teeth of the first roller 17 with clearance. The composite sheet is then inserted between the two toothed rollers 17, 17 in this state and thus subjected to the treatment that confers stretchability.A configuration can be adopted in which both toothed rollers 17, 17 of the pair are driven by a single drive source (double-rotating rollers), or a configuration can be adopted in which only one of the two toothed rollers 17 of the pair is driven by a single drive source (follower rollers). Regarding the tooth profile of the toothed rollers 17, a commonly used involute tooth profile or cycloid tooth profile can be used. An involute tooth profile or a cycloid tooth profile with a reduced face width is [missing information]. preferable. Regarding the treatment achieving elasticity, the treatment achieving elasticity disclosed in the literature patent 1 can be used as appropriate. Thanks to the stretch-inducing step, the thickness of the stretchable sheet 1 is increased preferably by 1.1 times or more, and more preferably by 1.3 times or more, preferably by 4 times or less, and more preferably by 3 times or less, and, specifically, is increased, preferably, by 1.1 to 4 times and by 1.3 to 3 times, compared to the thickness of the composite sheet before the stretch-inducing step. Thus, the constituent fibers of both sheet materials 2 and 3 are plastically deformed and elongated, and consequently the fibers become thinner. At the same time, sheets 2 and 3 become even more voluminous and therefore have a favorable tactile feel and damping properties. Although the present invention has been described based on a preferred embodiment thereof, the present invention is not limited to that embodiment. For example, the arrangement of the spinning nozzles of the spinning head according to the present invention is not limited to that of the preceding embodiment and can be modified accordingly without departing from the general meaning of the present invention. For example, the number of rows of nozzles 12L constituting the staggered arrangement portion 12A is not particularly limited and can be two, as shown in Figure 5, or three or more. The shape of the spinning nozzles 12 in a plan view and similar can be adjusted according to the intended use and similar of the stretchable sheet, which is an object to be produced, and is not particularly limited. The stretchable sheet of an absorbent article produced by the production process of the present invention can be used as an outer layer of a pull-on disposable diaper, for example. There are no limitations to this use, and the stretchable sheet can also be used advantageously as a constituent material of an absorbent article such as a sanitary napkin or a disposable diaper. Examples of constituent material of an absorbent article include a fluid-permeable sheet (comprising a top sheet, an underlayer, etc.) that is located closer to the skin than an absorbent organ, a sheet forming the outer surface of a disposable diaper, and a sheet to impart elasticity and stretchability to a portion below the waist, a portion of the waist, a portion around the leg, etc. The stretchable sheet can be used as a sheet forming a wing of a sanitary napkin, etc.The stretchable sheet can be used for a section to which stretchability is desired, etc., of sections other than those described above. In the case where the stretchable sheet of an absorbent article produced according to the production process of the present invention is to be used as a constituent material of an absorbent article, it is only required to add a step consisting of incorporating the stretchable sheet into an absorbent article by joining the stretchable sheet to. another constituent material (e.g. an absorbent organ) after the step conferring stretchability. In this document, where an upper limit value or a lower limit value, or upper and lower limit values ​​of a numeric value, are specified, the upper and lower limit values ​​themselves are also included. Furthermore, even if not explicitly stated, it is interpreted that all numeric values, or ranges of numeric values, equal to or less than the upper limit value of that numeric value, or equal to or greater than its lower limit value, or within the range between its upper and lower limit values, are described. As used herein, "One," "a," and other terms are interpreted as one or more. In view of the disclosure of the above document, it should be understood that various modifications and changes may be made to the present invention.Consequently, it should be understood that the present invention can also be implemented in an embodiment not clearly specified in this document, without departing from the technical scope based on the description of the claims. The complete disclosure of the above patent literature is incorporated in this document as an integral part of its contents. This application is a national phase application of an international application filed on April 1, 2019, which is based on and claims the benefit of Japanese patent application No. 2018-147827 filed on August 6, 2018, and international application No. PCT / JP2019 / 01441717 filed on April 1, 2019, and the entire contents of both applications are incorporated in this document as an integral part thereof. The invention further discloses the following stretchable sheets and manufacturing methods for this purpose. <]> Stretchable sheet for an absorbent article, in which a plurality of elastic filaments arranged to stretch in one direction without crossing each other are joined to a stretchable sheet material along their entire length in a substantially unstretched state, in which part or all of the plurality of elastic filaments are narrowed filaments having at least one narrow portion in a cross-section that is orthogonal to a longitudinal direction in which the elastic filaments extend. <2> Stretchable sheet for an absorbent article as stated in clause <1> , in which the cross-section of each constricted filament that is orthogonal to the longitudinal direction has a shape in which a plurality of circles are connected together in a state of partial overlap, and a center-to-center distance between adjacent circles is shorter than the sum of a radius of one of the circles and a radius of a second of the circles, and longer than the shorter radius of the radius of the first circle and the radius of the second circle. <3> Stretchable sheet for an absorbent article as stated in clause <1> Or <2> , in which the ratio of the number of said shrunken filaments to the number of said elastic filaments is from 5% to 90%. <d> Stretchable sheet for an absorbent article as stated in either clause <1> has <3> , wherein the ratio of the number of said shrunken filaments to the number of said elastic filaments is from 5% to 90%, preferably from 20% to 80%, more preferably from 50% to 70%. <5> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <4> , in which the ratio of the number of said shrunken filaments to the number of said elastic filaments is 50% to 70%. <6> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <5> , which includes a plurality of said narrowed filaments, wherein the ratio of the number of narrowed filaments having a narrow portion to the number of said narrowed filaments is 50% or more. <7> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <6> , which includes a plurality of said shrunken filaments, in which the ratio of the number of narrowed filaments having a narrow portion to the number of said narrowed filaments is 50% to 100%, preferably 60% to 100%, more preferably 90% to 100%. Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <7> , which includes a plurality of said shrunken filaments, in which the ratio of the number of narrowed filaments having a narrow portion to the number of said narrowed filaments is 90% to 100%. <9> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <8> , in which an average value of an end-to-end distance between elastic filaments that are adjacent to each other is 0.3 mm to 2 mm. <10> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <9> , wherein an average value of the end-to-end distance between elastic filaments that are adjacent to each other is 0.4 mm to 1.2 mm, preferably 0.6 mm to 1 mm, more preferably 0.6 mm to 0.8 mm. Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <10> , in which an average value of an end-to-end distance between elastic filaments that are adjacent to each other is 0.6 mm to 0.8 mm. <12> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <11> in which, in a cross-section of each shrunken filament that is orthogonal to the longitudinal direction, the maximum length of the shrunken filament is from 100 µm to 800 µm. <1]3> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <12> , wherein, in a cross-section of each shrunken filament that is orthogonal to the longitudinal direction, the maximum length of the shrunken filament is from 100 µm to 800 µm, preferably from 100 µm to 400 µm, more preferably from 200 µm to 500 µm, especially preferably from 200 µm to 270 µm. <]4> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <13> , in which, in a cross-section of each shrunken filament that is orthogonal to the longitudinal direction, the maximum length of the shrunken filament is from 200 µm to 270 µm. <15> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <14> , wherein the elastic filaments that are joined to the sheet material in the substantially unstretched state are joined to the stretchable sheet material along their entire length in a state in which the elastic filaments do not contract when an external force is removed. <16> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <15> , wherein a narrowed filament having a narrow portion has a pair of indented portions in a cross-sectional view of the narrowed filament that is orthogonal to the longitudinal direction, the indented portions being indented from a peripheral surface of the filament towards the inner side of the cross-section. <17> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <16> , wherein a thickness of the stretchable sheet for an absorbent article is 0.32 mm to 0.5 mm, preferably 0.36 mm to 0.5 mm, more preferably 0.39 mm to 0.4 mm. <18> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <17> in which the thickness of the stretchable sheet is from 0.39 mm to 0.4 mm. <]9> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <18> , wherein a peel resistance of the stretchable sheet for an absorbent article is 5 cN / filament to 30 cN / filament, preferably 10 cN / filament to 20 cN / filament, more preferably 10 cN / filament to 18 cN / filament. <20> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <19> , in which a peel resistance of the stretchable sheet for an absorbent article is 10 cN / filament to 18 cN / filament. <21> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <20> , wherein the ratio of a charge of the stretch sheet for an absorbent article when stretched 100% along the extension direction of the elastic filaments and reversed 50% from this state to a charge of the stretch sheet when stretched 50% along the extension direction of the elastic filaments is 45% to 100%, preferably 50% to 100%. <22> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <21> , wherein the ratio of a charge of the stretch sheet for an absorbent article when stretched 100% along the extension direction of the elastic filaments and reversed 50% from this state to a charge of the stretch sheet when stretched 50% along the extension direction of the elastic filaments is 50% to 100%. <23> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <22> , wherein a load on the stretchable sheet for an absorbent article when stretched 100% along the extension direction of the elastic filaments and reversed 50% from that state is 80 cN / 50 mm to 150 cN / 50 mm, preferably from 120 cN / 50 mm to 135 eN / 50 mm. <24> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <23> , in which a load of the stretchable sheet for an absorbent article when stretched 100% along the extension direction of the elastic filaments and reversed 50% from this state is 120 cN / 50 mm to 135 cN / 50 mm. <25> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <24> , wherein a load of the stretchable sheet for an absorbent article when stretched 50% along the extension direction of the elastic filaments is 80 cN / 50 mm to 600 cN / 50 mm, preferably 120 cN / 50 mm to 300 cN / 50 mm, more preferably 245 cN / 50 mm to 250 cN / 50 mm. <26> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <25> , in which a load of the stretchable sheet for an absorbent article when stretched 50% along the extension direction of the elastic filaments is 245 cN / 50 mm to 250 cN / 50 mm. <27> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <26> , in which, concerning the number of said elastic filaments, a filament which is incorporated into the stretchable sheet for an absorbent article while remaining in a post-spinning state, the shrunken filament having one narrow portion, and the shrunken filament having two narrow portions are each counted as one elastic filament. <28> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <27> , in which the narrow portion extends in the longitudinal direction of the elastic filaments. <29> Stretchable sheet for an absorbent article as stated in any of the clauses <1> has <28> , in which the plurality of elastic threads are bonded by fusion to the stretchable sheet material along their entire length in a substantially unstretched state. <30> Absorbent article including the stretchable sheet for an absorbent article as stated in any of the clauses <1> has <29> , <31> Disposable pull-on diaper, comprising a stretchable sheet for an absorbent item as stated in any of the clauses <1> has <29> is used as the outer casing. <32> A method for producing a stretchable sheet for an absorbent article, the method comprising a fusion bonding step consisting of bringing a plurality of elastic filaments, which are spun from a plurality of spinning nozzles and are brought in a molten or softened state, into contact with a sheet of raw material of a sheet material before the elastic filaments solidify, thereby fusion-bonding the elastic filaments to the sheet of raw material, in which the fusion bonding step includes receiving the elastic filaments in the molten or softened state from the spinning nozzles using a spinning head and a receiving means which receives the elastic filaments from the spinning nozzles of the spinning head at a receiving speed of 40 m / min to 200 m / min, and the spinning head includes a plurality of rows of nozzles in each of which a plurality of said spinning nozzles which are arranged at given intervals in a first direction are formed in a second direction which is orthogonal to the first direction, and positions of the spinning nozzles in the rows of nozzles which are adjacent to each other in the second direction are offset from each other in the first direction. <33> Method for producing a stretchable sheet for an absorbent article as stated in clause <32> , in which, in the fusion bonding stage, the elastic filaments in the molten or softened state are spun from the spinning nozzles at a resin evacuation speed of 5 m / min to 30 m / min. <34> Method for producing a stretchable sheet for an absorbent article as stated in clause <32> Or <33> , in which the reception speed is from 75 m / min to 150 m / min. <35> Method for producing a stretchable sheet for an absorbent article as stated in any of the clauses <32> has <34> , wherein, in the rows of nozzles which are adjacent to each other in the second direction, a center-to-center distance in the first direction between any single nozzle in one of the rows of nozzles and a nozzle which is closest to the single nozzle in the other row of nozzles is 1 mm or less. <36> Method for producing a stretchable sheet for an absorbent article as stated in any of the clauses <32> has <35> The process includes a stretchability step consisting of allowing a composite sheet in which several elastic filaments are fusion-bonded to the raw material sheet to pass between a pair of toothed rollers in each of which teeth and bottoms are formed alternately in a circumferential direction of the latter, thus conferring stretchability to the composite sheet. <37> A process for producing an absorbent article, the process comprising a step of incorporating the stretchable sheet for an absorbent article as stated in any of the clauses <1> has <29> in an absorbent article. <38> A method for producing an absorbent article, the method comprising a step of joining a stretchable sheet for an absorbent article that has been produced using the production method as set forth in any of the clauses <32> has <36> to another constituent material. Examples The present invention will be described in more detail below with the aid of examples. However, the present invention is not limited in all respects by the following examples. Example | : A drawing sheet having a configuration similar to that of the drawing sheet shown in Figures 1(a), 1(b) and 2 and containing a plurality of elastic filaments including shrunken filaments was produced using an apparatus having a configuration similar to the spinning apparatus shown in Figures 4 to 6 and an apparatus having a configuration similar to the traction device shown in Figure 7. Specifically, a composite sheet was obtained using a spinning apparatus comprising a spinning head in which all the spinning nozzles were arranged in a staggered pattern, such as the spinning head 11, and the composite sheet was made to pass through a traction device comprising a pair of toothed rollers in each of which teeth and bottoms were formed alternately in the circumferential direction, such as the pair of toothed rollers 17, as shown in Figure 7.Thus, stretchability was imparted to the composite sheet, and a stretchable sheet whose elastic filaments include filaments with a narrow portion was produced. The spinning nozzle pitch, resin discharge rate, and absorption rate of the apparatus used are shown in Table 1 below. The configuration of filaments with a narrow portion included in the elastic filaments of the produced stretchable sheet is as shown in Table 1 below. The following and similar materials were used: - Elastic filaments: a styrene-based thermoplastic elastomer; - Sheet materials: an air-permeable non-woven fabric with a surface mass of 20 g / m² and composed of a composite fiber (non-elastic fiber with a fiber thickness of 3.3 dtex) in which a core part is made of PET and a sheath of PE; and - Surface mass of stretchable sheet: 56 g / m². Examples 2 to 4: A stretchable sheet was produced in the same way as the one in example |, except that the resin discharge rate and absorption rate were modified. Comparative example 1: A stretchable sheet was produced in the same way as the one in example |, except that the resin flow rate and absorption rate were modified. Comparative example 2: A stretchable sheet was produced in the same way as in the example |, except that a spinning head in which all the spinning nozzles were arranged linearly in a single row was used. Comparative Example 3: A stretchable sheet was produced in the same way as in Example 1, except that the resin discharge rate was modified and a spinning head was used in which all the spinning nozzles were arranged linearly in a single row with a pitch of | mm. Evaluation tests: Regarding the stretch sheets produced in Examples 1 through 4 and the stretch sheets produced in Comparative Examples 1 through 3, the thickness of each sheet was measured by sandwiching the sheet between flat plates under a load of 0.5 cN / cm² and measuring the distance between the flat plates using a laser thickness gauge manufactured by Keyence Corporation. After each sheet of stretch material was held in a mandrel, the sheet material was peeled at a speed of 300 mm / min, and the maximum load at that time was measured using a tensile testing apparatus manufactured by Shimadzu Corporation, thus measuring the peel strength of the stretch sheet.The stretch and contraction capacity of the stretch sheet during a 100% elongation cycle test was measured using the method described above, in order to measure the 50% return load and the 50% stretch load of the sheet. Appearance was visually assessed using the evaluation criteria below. Table 1 presents the results. The appearance of a stretch film was assessed by visually observing the stretch sheet being evaluated. A stretch sheet in which no holes or similar defects were observed was rated as A, a stretch sheet in which a small hole or similar defect was observed was rated as B, and a stretch sheet in which a hole or similar defect was observed was rated as C. Regarding the ratio of shrunken filaments to elastic filaments, a section of a stretchable sheet cut across its width was magnified under a microscope manufactured by Keyence Corporation. One hundred elastic filaments were observed in cross-section. The number of filaments with a narrow portion out of these 100 elastic filaments was counted, and this count was used to calculate the number of shrunken filaments. The number of shrunken filaments with a narrow portion out of the shrunken filaments described above was counted, and this count was used to calculate the ratio of the number of filaments with a narrow portion to the number of shrunken filaments.Regarding the end-to-end distance between adjacent elastic filaments, a cut surface of a stretchable sheet cut in the width direction was magnified under a microscope manufactured by Keyence Corporation, and the end-to-end distance was measured at 100 random points, and an average of the measured values ​​was used as the end-to-end distance. Table inserted as an image: [Tables 1] [Table 1] EE [5x1 [Ex 2 |Ex 3 |Bx 4 Ex. com. | Ex. Ex 1 com.2 | com 3 where of | Present | Present | Present | Present | Abseat | Absent | Absent | Presence absence fitament shrunk Relationship between | Radius <= Radius; distance radius < center to center distance center, radius, adjacent ridges Ratio of the number of "shrinking flamingos" to the | % number of elastic flamingos : All between adjacent elastic flamingos Length not flamingo narrowed in the width direction of| Nozzle shape En Es En ée | Rancë Qquiacos | quincoss | quincosc wique | unique ces ces es + [12 [6 |32 [24 [12 Speed ​​m | resin evacuation 24 less —+ | 7 | 80 | 200 | 156 | 150 | 40 Reception speed | 150 [mis Step: fri [0.5 [os [os [os [os [1e of Élage Sheet thickness mm [os [039 [036 [ass [036 [ass eticable | 18 | 12 [22 [0 [24 Resistance to peeling of the 2% sheet 3rd stretchable Top t — [at |a [a | |e [a of Appearance (formation of tou) of the Fensille stretchable — | 118 | 124 | 137 | 126 | 116 | 59 Charge & return at 50% under the sheet mm stretched | 258 | 248 [270 days |263 | 138 Stretching charge: ES 5096 of ta 50 1259 stretchable sheet | 4th | 46 | 50 [st [4 ES |5 Tetous load ratio 3 50% | 5, from 50% of the stretchable sheet As shown in Table 1, the stretch sheets in Examples 1 to 4 contained shrunken filaments and had a 50% return load equal to or greater than that of the stretch sheet in Comparative Example 1, but nevertheless had a greater end-to-end distance (pitch) between adjacent elastic filaments and a greater thickness, compared to the stretch sheet in Comparative Example 1. The stretch sheets in Examples 1 to 4 had a 50% return load equal to or greater than that of the stretch sheet in Comparative Example 2, but their appearance nevertheless remained favorable compared to the stretch sheet in Comparative Example 2. Although the stretch sheets in Examples 1 to 4 retained a favorable appearance, as is the case for the stretch sheet in Comparative Example 3, these stretch sheets had a significantly higher 50% return load.From these results, it can be seen that, according to the stretch film of the present invention, since the shrunken filaments are contained within it, it is possible to improve the tensile strength while maintaining a favorable tactile feel and appearance. Based on the production conditions used in Examples 1 to 4, it can be seen that a stretchable sheet containing shrunken filaments and having excellent tactile feel... A 50% return load and appearance can be efficiently produced by using a spinning head in which spinning nozzles are arranged in a staggered pattern and by fixing the receiving speed or discharge speed and the resin receiving speed within a predetermined range. Industrial applicability

[0069] According to the stretchable sheet of the present invention, it is possible to provide a stretchable sheet in which stress can be improved while maintaining a favorable tactile feel and appearance. According to the manufacturing process of a stretchable sheet of the present invention, it is possible to provide a production method for such a sheet in which such a stretchable sheet can be produced efficiently. < / d>

Claims

Demands

1. Stretchable sheet for an absorbent article, in which a plurality of elastic filaments that are arranged in such a way as to extend in a Directions without crossing are joined to a stretchable sheet material along their entire length in a virtually unstretched state, in which part or all of the plurality of filaments Elastics are narrowed filaments having at least one narrow portion in a cross-section that is orthogonal to a direction of extension in which the elastic filaments extend.

2. Stretchable sheet for an absorbent article according to claim 1, in which the cross-section of each narrowed filament which is or- thogonal to the extension direction has a form in which a A plurality of circles are linked together in an overlapping state. partial, and a center-to-center distance between adjacent circles is shorter that the sum of a radius of the first circle and a radius of a second circle, and longer than the short radius of the radius of the first circle and the radius of the second circle.

3. Stretchable sheet for an absorbent article according to claim 1 or 2, in which the ratio of the number of said shrunken filaments to the the number of said elastic filaments is from 5% to 90%.

4. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 3, in which the ratio of the number of said filaments shrunk on the number of said elastic filaments is 20% to 80%.

5. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 4, in which the ratio of the number of said filaments reduced by 50% to 70% in the number of said elastic filaments.

6. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 5, which comprise a plurality of said narrowed filaments, in which the ratio of the number of shrunken filaments having a part narrow on the number of said shrunken filaments is 50% or more.

7. Stretch sheet for an absorbent article according to any of the re- demands | to 6, which includes a plurality of said shrunken filaments, in which the ratio of the number of shrunken filaments having a narrow portion on the number of said narrowed filaments is 50% to 100%.

8. Stretchable sheet for an absorbent article according to any of the re- demands | at 7, which includes a plurality of said shrunken filaments, in which the ratio of the number of shrunken filaments having a narrow portion on the number of said narrowed filaments is 90% to 100%.

9. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 8, in which an average value of a distance end to end between the elastic filaments that are adjacent to each other others in the width direction are 0.3 mm to 2 mm.

10. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 9, in which an average value of a distance end to end between the elastic filaments that are adjacent to each other other is from 0.4 mm to 1.2 mm.

11. | Stretchable sheet for an absorbent article according to any of the re- claims 1 to 10, in which an average value of a distance end to end between the elastic filaments that are adjacent to each other other is 0.6 mm to 0.8 mm.

12. Stretchable sheet for an absorbent article according to any of the re- demands | at 11, in which, in the cross-section of each filament shrinks orthogonally to the direction of extension, the length The maximum size of the shrunken filament is 100 µm to 800 µm.

13. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 12, in which, in a cross-section of each narrowed filament that is orthogonal to the longitudinal direction, The maximum length of the shrunk filament is 100 µm to 400 µm.

14. | Stretchable sheet for an absorbent article according to any of the re- claims 1 to 13, in which, in a cross-section of each narrowed filament that is orthogonal to the longitudinal direction, The maximum length of the shrunk filament is 200 µm to 270 µm.

15. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 14, in which the elastic filaments that are joined to the sheet material in its substantially unstretched state are joined to sheet material stretches along its entire length in a state in which elastic lilacs do not contract when a force The external part is removed.

16. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 15, in which a narrowed filament having a portion narrow has a pair of recessed portions in a cross-sectional view transverse of the narrowed filament which is orthogonal to the longitudinal direction tudinal, the sunken portions being sunken from a peri- surface pherical filament towards the inner side of the cross-section.

17. | Stretchable sheet for an absorbent article according to any of the re- sales 1 to 16, in which a thickness of the stretchable sheet for an absorbent article is 0.32 mm to 0.5 mm.

18. | Stretchable sheet for an absorbent article according to any of the re- sales 1 to 17, in which a thickness of the stretchable sheet for an absorbent article is 0.39 mm to 0.4 mm.

19. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 18, in which there is resistance to leaf peeling Stretchable for an absorbent article is 5 cN / filament to 30 cN / filament.

20. | Stretchable sheet for an absorbent article according to any of the re- claims 1 to 19, in which there is resistance to leaf peeling The stretchable strength for an absorbent article is 10 cN / filament to 18 cN / filament.

21. Stretchable sheet for an absorbent article according to any of the re- demands 1 to 20, in which the ratio of a charge of the sheet stretchable for an absorbent item when stretched 100% along of the direction of extension of the elastic filaments and reversed by 50% from this state on a load of the stretchable sheet when it is stretched 50% along the extension direction of the elastic filaments is from 45% to 100%.

22. Stretchable sheet for an absorbent article according to any of the re- demands | at 21, in which the report of a charge of the sheet stretchable for an absorbent item when stretched 100% along of the direction of extension of the elastic filaments and reversed by 50% from this state on a load of the stretchable sheet when it is stretched 50% along the extension direction of the elastic filaments is from 50% to 100%.

23. Stretchable sheet for an absorbent article according to any of the re- demands 1 to 22, in which a charge of the stretchable sheet for an absorbent item when stretched 100% along the direction of extension of the elastic filaments and reversed by 50% from this state is from 80 cN / 50 mm to 150 cN / 50 mm.

24. Stretchable sheet for an absorbent article according to any of the re- demands 1 to 23, in which a charge of the stretchable sheet for an absorbent item when stretched 100% along the direction of extension of the elastic filaments and reversed by 50% from this state is from 120 cN / 50 mm to 135 cN / 50 mm.

25. Stretchable sheet for an absorbent article according to any of the re- demands | at 24, in which a charge of the stretchable sheet for an absorbent article when stretched 50% along the direction The extension of elastic filaments is from 80 cN / 50 mm to 600 cN / 50 mm.

26. | Stretchable sheet for an absorbent article according to any of the re- demands 1 to 25, in which a charge of the stretchable sheet for an absorbent article when stretched 50% along the direction The extension of the elastic filaments is 245 cN / 50 mm to 250 cN / 50 mm.

27. ​​| Stretchable sheet for an absorbent article according to any of the re- claims 1 to 26, in which, concerning the number of said elastic filaments, a filament that is incorporated into the stretchable sheet for an absorbent item while remaining in a post-spinning state, the a narrowed filament having a narrow portion, and the narrowed filament having two narrow portions are each counted as a filament elastic.

28. | Stretchable sheet for an absorbent article according to any of the re- claims 1 to 27, in which the narrow portion extends into the direction of extension of elastic filaments.

29. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 28, in which the plurality of elastic filaments are joined to the sheet material by fusion bonding.

30. Stretchable sheet for an absorbent article according to any of the re- claims 1 to 29, in which the narrow portion has a portion embedded in a cross-sectional view of the shrunken filament, the embedded portion being embedded from a peripheral surface of the filament towards the inner side of the cross-section and being in regarding the sheet material, and in which the narrow portion extends along the entire length of the filaments elastic in the direction of extension.

31. Absorbent article comprising the stretchable sheet for an absorbent article according to any one of claims 1 to 30.

32. Pull-on disposable diaper, in which the stretchable sheet for an article absorbent according to any one of claims 1 to 30 is used as an outer casing.

33. Method for producing a stretchable sheet for an absorbent article, the process comprising a fusion bonding step consisting of bringing a plurality of elastic filaments, which are spun from a plurality of spinning nozzles and are brought into a molten or softened state contact with a sheet of raw material of a sheet material before the elastic filaments solidify, thus bonding by fusion elastic filaments attached to the raw material sheet, in which the fusion linking step includes the reception of elastic filaments in the molten or softened state, from the nozzles of spinning, using a spinning head and a receiving means which re- receives the elastic filaments spun from the spinning nozzles of the spinning head with a receiving speed of 40 m / min to 200 m / min, and the spinning head includes a plurality of rows of nozzles in each of which a plurality of said spinning nozzles are arranged at given intervals in a first direction are formed in a second direction which is orthogonal to the first direction, and of positions of the spinning nozzles in the rows of nozzles which are ad- underlying each other in the second direction are offset one of the others in the first direction.

34. Method for manufacturing a stretchable sheet for an absorbent article according to claim 33, wherein, during the bonding step by melting, the elastic filaments in the molten or softened state are spun to starting from the spinning nozzles at a resin discharge speed of 5 m / min to 30 m / min.

35. Method for manufacturing a stretchable sheet for an absorbent article according to claim 33 or 34, wherein the reception speed is from 75 m / min to 150 m / min.

36. Method for manufacturing a stretchable sheet for an absorbent article according to any one of claims 33 to 35, wherein, in the rows of nozzles adjacent to each other in the second direction, a center-to-center distance in the first direction between a single nozzle any one in one of the rows of nozzles and a nozzle that is the most close to the single nozzle in the other row of nozzles is 1] mm or Less.

37. Method for manufacturing a stretchable sheet for an absorbent article according to any one of claims 33 to 36, the process including a stretchability-conferring step consisting of allowing a composite sheet in which the plurality of elastic filaments are bonded by fusion to the sheet of raw material to pass between a pair of toothed rollers in each of which teeth and bottoms are formed alternately in a circumferential direction of those- here, to impart stretchability to the composite sheet.

38. | Method for manufacturing an absorbent article, the method comprising a step of incorporating the stretchable sheet for an absorbent article according to any one of claims 1 to 30 in an article absorbent.

39. A method for producing an absorbent article, the method comprising a step of attaching a stretchable sheet to an absorbent item which was produced using the production process according to one any of claims 33 to 37 to another constituent material.