JP5063315B2 - Telescopic sheet - Google Patents

Description

  The present invention relates to an elastic sheet formed by combining an elastic filament and a nonwoven fabric.

  For example, a technique described in Patent Document 1 is known as a conventional technique related to a stretchable sheet formed by combining an elastic fiber and a nonwoven fabric. The stretchable sheet described in the same document is composed of a first nonwoven fabric layer 122, a second nonwoven fabric layer 126, and an elastomer layer 124 located between both nonwoven fabric layers, as shown in FIG. ing. The elastomer layer 124 is composed of a scrim, a perforated film, an elastomer woven fabric, and a nonwoven fabric. FIG. 1 of this document describes that the elastomer layer 124 is composed of an elastomer scrim 130 including a plurality of first strands 125 and a plurality of second strands 127 orthogonal to each other. Due to the elastomer layer 124 having such a structure, when the stretchable sheet described in Patent Document 1 is stretched in a certain direction, the sheet width in the direction orthogonal to the stretched direction becomes narrower. A phenomenon, that is, a phenomenon of width shrinkage occurs. Therefore, when this stretchable sheet is used, for example, as an outer wrapping material for a pant-type diaper, the material is stretched in the waistline direction and the width shrinkage occurs in the longitudinal direction of the diaper. To do. Further, considering the configuration of the diaper and the movement of the user, non-uniform expansion occurs in the width direction, and the width contraction becomes even more pronounced. Moreover, since the strands 125 and 127 and the nonwoven fabric layers 122 and 126 are joined by heat and pressure, the strands 125 and 127 bite into the nonwoven fabric layers 122 and 126, and the soft feeling of the nonwoven fabric layers 122 and 126 is impaired. It is. Since the strands 125 and 127 and the nonwoven fabric layers 122 and 126 are joined by heat and pressure applied from the nonwoven fabric 122 or 126 side, the temperature on the outer nonwoven fabric side tends to be high at the time of adhesion, and the strand side The temperature tends to be lower than that of the nonwoven fabric. For this reason, when trying to obtain sufficient bonding strength, there is a problem that the nonwoven fabric is melted before the strands by heat and pressure and is formed into a film. Moreover, since it is necessary to melt the resin of the internal fiber in contact with the strand, there is a problem in that the temperature and pressure are increased and the texture is deteriorated. If a non-woven fabric with a high melting point is used, the non-woven fiber itself will not melt, but it will be difficult to fuse with the elastomer scrim, and it will be difficult to use a non-woven fabric with a soft texture and a relatively low melting point. .

  As another technique of the stretchable sheet, a technique described in Patent Document 2 is also known. As shown in FIGS. 1, 2 and 5 of the same document, the elastic sheet described in the document forms a large number of arch portions 13 on the sheet 12 by corrugated members 20 and 21 having a gear shape, The elastic strand 16 is fused to the top (bottom) of the arch portion 13. The elastic strand 16 is extruded from the die 22 in a molten state, and is fused to the sheet 12 in an unstretched state. Accordingly, the elastic strand 16 is bonded to the sheet 12 by point contact, and it is not easy to increase the bonding strength due to this. Further, the stretchable sheet described in the document cannot be stretched beyond the flat arch portion 13 and has a so-called stretch stop. Further, the amount of use of the sheet 12 increases as much as the arch portion 13 is formed to loosen the sheet 12, which is not economical and the air permeability is also lowered. The document describes that the sheet 12 before being bonded to the elastic strand 16 may be bonded to the elastic strand in a state in which the sheet 12 is already stretchable in the original fabric state. However, it is difficult to convey a non-woven fabric that is stretchable in the flow direction without being stretched. Furthermore, when the elastic sheet described in Patent Document 2 is wound up in a roll shape, stress relaxation occurs in which the contraction force gradually decreases because it is stored for a long time in a state stretched by the tension at the time of winding. Therefore, there was a problem in storage stability. When the post-processing for the sheet is performed in another different place, it is essential to take up the stretchable sheet in a roll shape in consideration of handling properties and transportability.

  Patent Document 3 describes a method in which after forming an elastic strand, the elastic strand is stretched in a cooled and solidified state, and then joined to a nonwoven fabric to obtain an elastic sheet. By returning the stretched portion of the elastic strand, the nonwoven fabric is loosened, and the stretchability is expressed within the range of the length. Since the elastic strand is cooled and solidified before joining with the nonwoven fabric, it is necessary to bond the elastic strand to the nonwoven fabric with an adhesive or the like. Therefore, it is necessary to increase the amount of the adhesive to obtain sufficient adhesive strength. If a large amount of adhesive is applied, the gap between the fibers of the non-woven fabric is filled, resulting in a decrease in air permeability. Moreover, since a plurality of fibers are bundled with an adhesive, the rigidity is increased. Therefore, it is difficult to obtain a soft and breathable sheet. In addition, since the elastic sheet described in the same document has the same structure as a normal elastic rubber body bonded with an elastic thread stretched, gathers are formed on the elastic sheet, and the touch is soft. It is inferior and does not have a cloth-like appearance. In a state where the gathers are formed, the elastic body is in an extended state as the nonwoven fabric tries to expand to the original state, and since the stress is gradually reduced, the contraction force gradually decreases because it is stored for a long time in the extended state. Stretching power decreases during long-term storage. Further, in the step of compounding with a nonwoven fabric or the like, when the elastic strand is stretched using a roll or transported while being held in a roll, the elastic strand sticks to the roll or causes thread breakage. There was a problem. In addition, since all of the elastic bodies have a relatively thick strand, the texture gives a feeling of being harsh, and the texture is not good.

  Apart from the above technology, an elastic stretchable composite sheet is proposed in which an elastic sheet made of elastic stretchable film or elastic stretchable continuous fiber and a non-elastic stretchable fiber assembly are laminated. (See Patent Document 4). The elastic sheet and the fiber assembly are joined at joints arranged intermittently. The constituent fibers of the fiber assembly are long fibers that are continuous between the joints. The long fibers are not welded or fused between the joints, and the fibers are separated and independent from each other. Moreover, this long fiber has drawn the irregular curve between junction parts.

  According to Patent Document 4, in this elastic stretchable composite sheet, since the long fibers of the fiber assembly draw an irregular curve between the joint portions, when the sheet is stretched, the stretch is the fibers. It is said that it will not be disturbed by the aggregate. However, since the long fibers of the fiber assembly are separated and independent from each other between the joint portions, the elastic stretchable composite sheet has low strength against tension. Also, the peel strength between the fiber assembly and the elastic sheet is low. In addition, the long fibers tend to float between the joints, whereby the sheet has a fuzzy appearance and the appearance is not good.

Special table 2003-524534 gazette Japanese National Patent Publication No. 10-501195 Special table 2003-533280 gazette JP 2001-79972 A

  Accordingly, an object of the present invention is to provide a stretchable sheet that can eliminate the drawbacks of the prior art described above.

  The present invention provides a stretchable sheet in which a large number of elastic filaments arranged so as to extend in one direction without crossing each other are joined to a stretchable nonwoven fabric over their entire length in a substantially non-stretched state. Is.

  In the present invention, a large number of molten elastic filaments spun from a spinning nozzle are drawn and stretched at a predetermined speed, and the elastic filaments are arranged in one direction without crossing each other before the elastic filaments are solidified. The elastic filament is fused to a non-woven fabric as described above, and then the composite having the elastic filament fused is stretched along the direction in which the elastic filament extends to impart stretchability to the composite. Is to provide.

  In the stretchable sheet of the present invention, since the elastic filaments are arranged so as to extend in one direction, the stretchable sheet can be extended in the extending direction of the elastic filament without causing width shrinkage. Further, the stretchable sheet of the present invention has high strength, and when the stretchable sheet is stretched, the elastic filament and the nonwoven fabric are hardly peeled off.

  The present invention will be described below based on preferred embodiments with reference to the drawings. FIG. 1 shows a partially broken perspective view of an embodiment of the stretchable sheet of the present invention. The elastic sheet 10 of this embodiment is composed of a total of two nonwoven fabrics, a first nonwoven fabric 11 and a second nonwoven fabric 12, and a large number of elastic filaments 13 sandwiched between the nonwoven fabrics. Each elastic filament 13 is joined to the first and second nonwoven fabrics 11 and 12. The first nonwoven fabric 11 and the second nonwoven fabric 12 may be of the same type or different types. The same kind of non-woven fabric as used herein refers to non-woven fabrics in which the non-woven fabric manufacturing process, the type of constituent fibers of the non-woven fabric, the fiber diameter and length of the constituent fibers, the thickness and basis weight of the non-woven fabric are all the same. When at least one of these is different, it is said that it is a different kind of nonwoven fabric. In the present invention, the elasticity means that when the force is released from a state where it can be stretched and stretched 100% with respect to the original length (the length becomes 200% of the original length). The property of returning to a length of 125% or less of the length.

  Each of the nonwoven fabrics 11 and 12 can be extended. Each nonwoven fabric 11 and 12 can extend in the same direction as the direction in which the elastic filament 13 extends. Stretchable means (a) when the constituent fibers themselves of the nonwoven fabrics 11 and 12 are stretched, and (b) even if the constituent fibers themselves are not stretched, the fibers that are bonded at the intersection are separated, This includes the case where the three-dimensional structure formed by a plurality of fibers is structurally changed due to bonding or the like, the constituent fibers are broken, or the slackness of the fibers is stretched to stretch as a whole nonwoven fabric.

  Each of the nonwoven fabrics 11 and 12 may be already stretchable in the state of the original fabric before being joined to the elastic filament 13. Alternatively, it is not stretchable in the state of the original fabric before being joined to the elastic filament 13, but is processed so as to be stretchable after being joined to the elastic filament 13, and becomes stretchable. Also good. Specific methods for making the nonwoven fabric stretchable include heat treatment, stretching between rolls, biting stretch using tooth gaps and gears, and tensile stretching using a tenter. In view of a preferable manufacturing method of the stretchable sheet 10 described later, the nonwoven fabrics 11 and 12 are the original ones because the transportability of the nonwoven fabrics 11 and 12 is improved when the elastic filaments 13 are fused to the nonwoven fabrics 11 and 12. In the opposite state, it is preferably not stretchable.

  Each nonwoven fabric 11, 12 is extensible and comprises substantially inelastic fibers, and is substantially inelastic.

Each elastic filament 13 is substantially continuous over the entire length of the stretchable sheet 10. The elastic filament 13 contains an elastic resin. The elastic filaments 13 are arranged so as to extend in one direction without crossing each other. However, the elastic filaments 13 are allowed to cross unintentionally due to inevitable fluctuations in the manufacturing conditions of the stretchable sheet 10. Each elastic filament 13 may extend linearly as long as it does not cross each other, or may extend while meandering.
The fact that the filaments do not cross each other means that there are almost no intersections. When there is an intersection point, it means that there are a plurality of fibers between the intersection points. Usually, however, it is rare that the lengths of fibers existing between the intersection points coincide with each other industrially. If stretching is performed while the lengths of the fibers existing between the intersections are different, stress is applied only to the shorter fibers contained between the intersections, and many fibers are placed. However, many fibers are not involved in elongation. When compared with fibers of the same weight, the shrinkage force becomes smaller as the number of fiber intersections increases. Therefore, cost is wasted. Considering expansion and contraction only in the vertical direction, if there are fibers in the horizontal direction like a net, not only are the fibers in the horizontal direction wasted, but also the intersections occur, and the fibers in the vertical direction are also wasted. A part will occur.
The direction in which the elastic filament 13 extends may coincide with the flow direction when the first and second nonwoven fabrics 11 and 12 are manufactured, or may be orthogonal to the flow direction when the nonwoven fabrics 11 and 12 are manufactured. . When the stretchable sheet 10 is manufactured according to a preferable manufacturing method described later, the extending direction of the elastic filament 13 coincides with the flow direction at the time of manufacturing the first and second nonwoven fabrics 11 and 12.

  The elastic filament 13 is bonded to the nonwoven fabrics 11 and 12 in a substantially non-stretched state. These nonwoven fabrics 11 and 12 can be extended. Since the elastic filament 13 is bonded to the nonwoven fabrics 11 and 12 in a state where the elastic filament 13 is not stretched, the stretchable sheet 10 of the present embodiment has an advantage that stretch (creep) does not occur due to stretching and the stretchability is not easily lowered. Furthermore, for example, when the elastic filament 13 is stretched twice and bonded to the nonwoven fabrics 11 and 12, if it is temporarily returned to 1.3 times the initial value, it can only be stretched up to 1.54 times from this state. However, when bonding is performed in a non-stretched state, the initial origin when the stretchable sheet is stretched is different, so that the stretchable length of the nonwoven fabrics 11 and 12 or the maximum elongation of the elastic filament 13 is stretched. There is an advantage that becomes possible.

  There are the following advantages in joining the elastic filament 13 to the nonwoven fabrics 11 and 12 in a state where the elastic filament 13 is not elongated. The stretchable sheet 10 of the present embodiment, for example, joins the substantially non-stretched elastic filament 13 to the non-stretched nonwoven fabrics 11 and 12 to form a take-up raw fabric (at this time, the elastic filament 13 and The bonded non-stretched nonwoven fabrics 11 and 12 are non-stretchable), and the unstretched nonwoven fabrics 11 and 12 can be stretched by drawing out the original fabric and stretching it in a separate process (for example, tooth gap stretching). Manufactured by making a non-woven fabric. In the state of the original fabric, the original fabric is non-stretchable and non-stretchable, so that no external force acts on the elastic filament 13. As a result, there is an advantage that even if the original fabric is stored for a long period of time, relaxation due to elongation does not occur.

  The elastic filament 13 can be a thread-like synthetic rubber thread or natural rubber. Alternatively, it may be obtained by dry spinning (melt spinning) or wet spinning. Among these, in view of a suitable manufacturing method to be described later, the elastic filament 13 is preferably obtained by direct melt spinning without temporarily winding or storing the elastic filament 13.

  The elastic filament 13 is preferably obtained by stretching a molten resin discharged from a nozzle on a spinning line. By stretching, the polymer constituting the elastic filament 13 is molecularly oriented in the length direction of the elastic filament 13, so that the going / returning ratio at the time of 50% elongation, which will be described later, is increased and the hysteresis loss is reduced. Further, a thin elastic filament can be obtained by stretching. From this point of view, the elastic filament 13 is preferably stretched 1.1 to 400 times, particularly 4 to 100 times. On the other hand, in Patent Document 2 described above, since the elastic strand extruded in a molten state from the die is joined to the sheet in an unstretched state, the hysteresis loss of the elastic strand is sufficiently small. Must not. Moreover, in patent document 3, when extending | stretching, since adhesive resin touches a roll directly, there exists a problem that an elastic strand winds.

  In particular, the elastic filament 13 is preferably formed by being stretched in a state where the elastic resin is melted or softened. This makes it possible to obtain a sufficiently thin filament, and the texture is improved for reasons described later. In addition, the elastic filament 13 which is stretched in a state where the elastic resin is melted or softened and bonded to the nonwoven fabrics 11 and 12 does not show a force to shrink, and the elastic filament 13 is not stretched. It will be in the same state as having joined to nonwoven fabrics 11 and 12 in a state. Specific operations for stretching in the present embodiment are as follows: (a) A resin as a raw material of the elastic filament 13 is melt-spun to obtain an unstretched yarn, and the elastic filament of the unstretched yarn is heated again to soften the temperature. (B) Operation for stretching in a state higher than (hard segment glass transition temperature Tg), and (b) operation for directly stretching a molten fiber obtained by melt spinning a resin as a raw material of the elastic filament 13 . When the stretchable sheet 10 is manufactured according to a preferable manufacturing method described later, the elastic filament 13 is obtained by directly stretching a molten fiber obtained by melt spinning.

  The elastic filament 13 obtained by drawing after spinning preferably has a diameter of 10 to 200 μm, particularly 20 to 130 μm. This range is determined in consideration of the texture of the stretchable sheet 10 and the productivity of the elastic filament 13. Specifically, if the diameter of the elastic filament 13 is too large, a step due to the elastic filament 13 is easily perceived when the elastic sheet 10 is touched. This step acts negatively on the texture of the stretchable sheet 10. From this point of view, it is preferable that the elastic filament 13 has a smaller diameter because only the texture of the nonwoven fabrics 11 and 12 is easily perceived. In addition, the elastic filament 13 is preferably thin in order to reduce the light transmittance of the nonwoven fabric so as to provide a so-called body fluid color concealing performance. Furthermore, in the elastic expression processing by the tooth space roll described later, the diameter of the elastic filament 13 is equal to or less than the tooth-to-tooth clearance between the tooth space rolls (preferred clearance is to increase the endurance of the tooth and the draw ratio by the amount of biting. Since the clearance is reduced at a higher point and is 250 μm or less, more preferably 200 μm or less, the elastic filament is less likely to be damaged (cracked or cut) during stretching. The ratio between the diameter of the elastic filament and the clearance is preferably 0.2 to 1, particularly 0.2 to 0.5. However, the smaller the elastic filament 13 is, the less easy it is to manufacture. Considering these, the diameter of the elastic filament 13 is preferably within the above-mentioned range.

  From the viewpoint of preventing the above-described step from being generated, the ratio of the diameter of the elastic filament 13 in the thickness direction of the elastic filament 13 to the thickness of the elastic sheet 10 is preferably 1 to 30%, particularly preferably 5 to 12%.

  The elastic filament 13 may have a circular cross section, but in some cases may have an elliptical or flat cross section. For example, when the stretchable sheet 10 is manufactured according to the manufacturing method described later, the cross section of the elastic filament 13 tends to be flat. In this case, in the elastic sheet 10, the elastic filament 13 has a flat major axis substantially in the same direction as the planar direction of the elastic sheet 10 and a short axis substantially in the same direction as the thickness direction of the elastic sheet 10. It is preferable that they are arranged as described above.

  When the cross section of the elastic filament 13 is flat, the ratio of long axis / short axis (average flatness ratio) is 1.0 to 7.0, particularly 1.1 to 3.0. This is preferable from the viewpoint that the bonding strength between the filament 13 and the constituent fibers of the nonwoven fabrics 11 and 12 and the hiding performance of the stretchable sheet 10 are increased. The elastic filaments 13 having a flat cross section are arranged so that the major axis direction thereof substantially coincides with the plane direction of the stretchable sheet 10. In addition, when the cross section of the elastic filament 13 is flat, the diameter of the elastic filament 13 means what averaged the major axis diameter and the minor axis diameter. The major axis of the elastic filament 13 having a flat shape refers to the length of the longest transverse line on the outer periphery of the elastic filament 13 extracted by microscopic observation. The short axis in the elastic filament 13 refers to the length of the short side when a rectangle having two sides parallel to the long axis determined as described above and circumscribing the outer periphery is drawn. These are measured with respect to five arbitrary elastic filaments, and the average flatness is defined as the average flatness, and the average diameter is defined as the diameter of the elastic filament.

  The elastic filament 13 is also preferably colored in a color different from the colors of the first and second nonwoven fabrics 11 and 12. Thereby, the elastic filament 13 can be seen through the first nonwoven fabric 11 and / or the second nonwoven fabric 12, and the design effect that the stretchable sheet 10 exhibits a striped pattern is exhibited. Such an effect becomes more remarkable especially when the thickness and basis weight of each nonwoven fabric are within the ranges described below.

  From the viewpoints of the stretchable sheet 10 exhibiting sufficient stretchability, the fabric-like texture, and the above-described design effects as necessary, the pitch of the adjacent elastic filaments 13 (adjacent The distance between the elastic filaments 13) is preferably 0.1 to 5 mm, particularly preferably 0.4 to 1 mm, provided that the diameter of the elastic filament 13 is in the above-described range.

  The elastic filament 13 is bonded to the nonwoven fabrics 11 and 12 over the entire length thereof. Here, “joining over the entire length” requires that all the fibers in contact with the elastic filament 13 (component fibers of the nonwoven fabrics 11 and 12) are joined to the elastic filament 13. In other words, it means that the elastic filament 13 and the constituent fibers of the nonwoven fabrics 11 and 12 are bonded to the elastic filament 13 in such a manner that there is no intentionally formed non-bonded portion. Since the elastic filament 13 is bonded to the nonwoven fabrics 11 and 12 over the entire length, the bonding force between the elastic strands 13 and the nonwoven fabrics 11 and 12 can be sufficiently increased. As a result, even if the elastic sheet 10 is stretched, the elastic filament 13 is difficult to peel from the nonwoven fabrics 11 and 12. If the elastic filament 13 peels from the nonwoven fabrics 11 and 12, in the natural state (relaxed state), floating occurs between the elastic filament 13 and the nonwoven fabrics 11 and 12, and wrinkles occur in the stretchable sheet 10. It becomes easy and lacks a sense of unity as the entire stretchable sheet 10.

  As a mode of joining the elastic filament 13 and the first and second nonwoven fabrics 11 and 12, for example, fusion is mentioned. When the elastic sheet 10 is manufactured according to a suitable manufacturing method described later, the elastic filament 13 is bonded to the nonwoven fabrics 11 and 12 by fusion bonding. The fusion includes both a state in which the elastic filament and the fibers constituting the nonwoven fabrics 11 and 12 are melted and bonded to each other, or one of them is melted and the other is intruded into and bonded to each other. According to this method, excessive heat is not applied to the nonwoven fabrics 11 and 12, and the elastic filaments 13 are fused to the nonwoven fabrics before the elastic filaments 13 obtained by melt spinning are solidified. Since only the fibers existing around the fiber are bonded to the elastic filaments 13 and the fibers located further away from the fibers maintain the texture of the nonwoven fabrics 11 and 12, the texture of the stretchable sheet 10 is excellent. There is an advantage that it is kept. In this case, an adhesive may be applied as an auxiliary joining means before joining the nonwoven fabrics 11 and 12 and the elastic filaments 13. Or after joining each nonwoven fabric 11 and 12 and the elastic filament 13, heat processing (steam jet, heat embossing), mechanical entanglement (needle punch, spunlace) etc. can also be performed as an auxiliary joining means. . However, these auxiliary joining means may damage the texture of the resulting stretchable sheet 10 or damage the elastic filament 13. Therefore, it is preferable to fuse the elastic filament 13 to the nonwoven fabrics 11 and 12 with the heat of fusion. However, when a heat treatment consisting of hot air blowing by an air-through method is used as an auxiliary joining means, the texture of the obtained stretchable sheet 10 is not impaired, and the nonwoven fabrics 11 and 12 having a high joining strength can be obtained. Is preferable.

  The stretchable sheet 10 is stretchable in the same direction as the direction in which the elastic filament 13 extends. The stretchability of the stretchable sheet 10 is expressed due to the elasticity of the elastic filament 13. When the stretchable sheet 10 is stretched in the same direction as the elastic filament 13 extends, the elastic filament 13 and the first and second nonwoven fabrics 11 and 12 extend. When the stretching of the stretchable sheet 10 is released, the elastic filament 13 contracts, and the first and second nonwoven fabrics 11 and 12 return to the state before stretching with the contraction.

  Unlike the sheet described in Patent Document 1 described above, in the stretchable sheet 10 of the present embodiment, there is no other elastic filament bonded in a state orthogonal to the elastic filament 13. Therefore, even if the stretchable sheet 10 is stretched in the same direction as the direction in which the elastic filament 13 extends, the stretchable sheet 10 stretches with little width shrinkage. That is, the stretchable sheet 10 has a substantially uniform width in the longitudinal direction in the stretched state. As a result, the handling property when the stretchable sheet 10 is conveyed in the extended state and processed is improved. Moreover, when the elastic sheet 10 is used, for example, as an outer wrapping material for a pants-type diaper, it is effectively prevented that the diaper is slipped or wrinkled while the diaper is worn. In addition, considering the configuration of the diaper and the movement of the user, non-uniform stretching occurs in the width direction, but there is almost no shrinkage in the width, and it is effective that the diaper is displaced or wrinkled. To be prevented. From this point of view, the stretchable sheet 10 preferably has a width shrinkage ratio of 1% to 10%, particularly 1% to 5% of the width before stretching when the stretchable sheet 10 is stretched 1.5 times. The width reduction can be calculated as (1−width after extension ÷ width before extension) × 100. The width after stretching is measured as follows. The sample is cut out with a width of 50 mm so that the length direction is substantially along the flow direction (within an angle difference of 15 degrees or less). The length is over 150 mm. While maintaining the width of the sample at 50 mm, both ends in the longitudinal direction of the sample are gripped at a gripping interval of 150 mm. At this time, care is taken so that the sample does not sag in the longitudinal direction and does not stretch. From this state, the width of the central portion in the length direction of the sample when the grip interval is extended to 1.5 times is measured, and the value is taken as the width after extension.

  2A and 2B are longitudinal sectional views along the extending direction of the elastic filament 13 in the stretchable sheet 10 according to the embodiment of the present invention. The embodiment shown in FIGS. 2 (a) and 2 (b) is a form that remarkably develops when tooth gap extension is used in the elastic expression processing step in the manufacturing process of the stretchable sheet 10. Fig.2 (a) is a longitudinal cross-sectional view of the elastic sheet 10 in a natural state (relaxed state), and FIG.2 (b) is a longitudinal cross-sectional view of the elastic sheet 10 in an expansion | extension state. In the natural state, the stretchable sheet 10 has a corrugated shape in which the top portions 14 'and the valley portions 14 "are alternately arranged. The top portion 14' and the valley portion 14" are connected via the ridge line portion 15 '. . The thickness of the ridge line portion 15 ′ is slightly smaller than the thickness of the top portion 14 ′ and the valley portion 14 ″, and light is more easily transmitted than the top portion 14 ′ and the valley portion 14 ″. When the stretchable sheet 10 is viewed in plan, the top portion 14 ′, the ridge line portion 15 ′, and the valley portion 14 ″ extend in a direction perpendicular to the extending direction of the stretchable sheet 10. Therefore, the stretchable sheet 10 has a natural state. Further, a horizontal stripe pattern due to the ridge portion 15 ′ that easily transmits light and the top portion 14 ′ and the valley portion 14 ″ that hardly transmit light appears slightly. When the stretchable sheet 10 is stretched, this horizontal stripe pattern may become more prominent depending on conditions such as an elastic expression process described later.

  That is, as shown in FIG. 2B, in the stretchable stretchable sheet 10, the high basis weight portions 14 and the low basis weight portions 15 are alternately arranged along the extending direction of the elastic filaments 13. . Each of the portions 14 and 15 extends in a band shape in a direction orthogonal to the direction in which the elastic filament 13 extends. The high basis weight portions 14 and the low basis weight portions 15 are alternately arranged at a constant period. About the high basic weight part 14, what protrudes above the sheet | seat 10 and what protrudes below the sheet | seat 10 are arrange | positioned alternately. The high basis weight portion 14 protruding above the sheet 10 is derived from the top portion 14 ′ of the sheet 10 in the natural state shown in FIG. On the other hand, the high basis weight portion 14 projecting to the lower side of the sheet 10 is derived from the trough portion 14 ″ in the sheet 10 in the natural state shown in FIG. 2 (a). 2 (a) is derived from the ridge line portion 15 'in the natural sheet 10. In the high basis weight portion 14 and the low basis weight portion 15, the degree of light transmission due to the difference in basis weight. As a result, the stretchable sheet 10 has a horizontal stripe pattern extending in a direction orthogonal to the extending direction of the elastic filaments 13, and the design is improved. Since the elastic sheet 13 also exhibits a striped pattern, the stretchable sheet 10 also exhibits a lattice pattern in which the striped pattern is combined with the striped pattern derived from the high basis weight portion 14 and the low basis weight portion 15. The design is even higher That. Also, as shown in FIG. 2 (a) and (b), as a preferred embodiment of the present invention, the upper or portions projecting of the lower sheet 10, the fiber is filled.

  The high basis weight portion 14 has a larger basis weight and a larger thickness than the low basis weight portion 15. As a result, the high basis weight portion 14 and the low basis weight portion 15 differ in the degree of light transmission, and a striped pattern is exhibited due to the difference. Each high basis weight portion 14 is substantially equal in width to each other, and similarly, each low basis weight portion 15 is also substantially equal in width to each other.

The thickness of the high basis weight portion 14 is preferably 0.3 to 10 mm, particularly preferably 0.5 to 1 mm. The thickness of the low basis weight portion 15 is preferably 0.1 to 3 mm, particularly preferably 0.2 to 0.6 mm from the viewpoints of stretchability and air permeability. The thickness is measured by the following method after the stretchable sheet 10 is left unloaded for 2 days or more in an environment of 20 ± 2 ° C. and 65 ± 5% RH. First, the stretchable sheet 10 is sandwiched between flat plates with a load of 0.5 cN / cm ^{2 in} a state where the stretchable sheet 10 is stretched 1.5 times. The cross section is observed with a microscope at a magnification of 50 to 200 times, and an average thickness is obtained in each field of view, and is obtained as an average value of the thicknesses of three fields of view. The high basic weight portion 14 and the low basic weight portion 15 are easily formed by manufacturing the stretchable sheet 10 according to the manufacturing method described later.

  Next, the constituent materials of the first and second nonwoven fabrics 11 and 12 and the elastic filament 13 constituting the stretchable sheet 10 will be described. As the fibers constituting the nonwoven fabrics 11 and 12, substantially inelastic fibers are used. Examples thereof include fibers made of polyethylene (PE), polypropylene (PP), polyester (PET or PBT), polyamide, and the like. The fibers constituting each of the nonwoven fabrics 11 and 12 may be short fibers or long fibers, and may be hydrophilic or water repellent. Further, core-sheath type or side-by-side composite fibers, split fibers, irregularly shaped cross-section fibers, crimped fibers, heat-shrinkable fibers, and the like can also be used. These fibers can be used singly or in combination of two or more. Each non-woven fabric 11, 12 can be a continuous filament or short-fiber non-woven fabric. In particular, from the viewpoint of making the stretchable sheet 10 thick and bulky, the nonwoven fabrics 11 and 12 are preferably short-fiber nonwoven fabrics. When the stretchable sheet 10 is used as a member that comes into contact with the skin, a short fiber nonwoven fabric with good texture may be used on the skin contact side, and a high-strength continuous filament nonwoven fabric may be used on the opposite surface.

  Each of the nonwoven fabrics 11 and 12 preferably has two or more constituent fibers of a low melting point component and a high melting point component. In that case, the constituent fibers are bonded to each other at the fiber intersection by heat fusion of at least the low melting point component. As the core-sheath type composite fiber composed of two or more components of a low melting point component and a high melting point component, those having a core of high melting point PET, PP and a sheath of low melting point PET, PP, PE are preferable.

The thickness of each nonwoven fabric 11 and 12 is preferably 0.05 to 5 mm, more preferably 0.1 to 1.0 mm, and still more preferably 0.15 to 0.5 mm. The thickness was measured by sandwiching the flat sheet between flat plates with a load of 0.5 cN / cm ² and observing the cross section of the stretchable sheet 10 with a microscope at a magnification of 50 to 200 times. It can obtain | require as an average value of thickness. The thickness of the entire sheet can be obtained by measuring the distance between the flat plates. The basis weight of each of the nonwoven fabrics 11 and 12 is preferably ³ to 100 g / m ² , particularly 10 to 30 g / m ² from the viewpoints of texture, thickness, and design properties.

It is preferable that each nonwoven fabric 11 and 12 consists of a substantially inelastic fiber from viewpoints, such as a texture and stickiness. The proportion of inelastic fibers in the nonwoven fabric is 70% by weight or more, preferably 90% by weight or more, and more preferably 100% by weight. Further, the substantially inelastic fiber may contain an elastic resin in the inelastic resin, and the proportion of the inelastic resin is 70% by weight or more, preferably 90% by weight, more preferably 100% by weight. Is good.

  In particular, it is preferable to use a non-elastic fiber whose fiber thickness is not uniform in the length direction (hereinafter, this fiber is referred to as an indefinite fiber). That is, indefinite-diameter fibers have a large fiber cross-sectional area (diameter) and a small part when viewed along the length direction. In the indefinite fiber, the diameter (cross-sectional area) may continuously change from the smallest part to the largest part. Alternatively, the diameter (cross-sectional area) of the fiber may change in a substantially step shape, as in the necking phenomenon observed in the undrawn yarn drawing process. An example of an inelastic fiber in which the fiber diameter (cross-sectional area) is changed in a substantially step shape is shown in FIG.

  The inelastic fiber is made from a fiber having a constant fiber diameter and a high elongation (for example, the maximum elongation of the fiber is 80 to 800%, particularly 120 to 650%). It is preferable at the point obtained. The elongation of the fiber conforms to JIS L-1015, based on the measurement environment temperature and humidity 20 ± 2 ° C., 65 ± 5% RH, tensile tester gripping distance 20 mm, tensile speed 20 mm / min. To do. In addition, when collecting fibers from an already manufactured non-woven fabric and measuring the elongation, when the gripping interval cannot be 20 mm, that is, when the length of the fiber to be measured is less than 20 mm, the gripping interval is set. Measure by setting to 10 mm or 5 mm.

  The high-stretch fiber is preferably a low-stretch inelastic fiber. When the stretchable sheet 10 of the present embodiment is manufactured using a low-stretched inelastic fiber as a raw material in accordance with the manufacturing method described later, the stretched low-stretched fiber is stretched in the elastic expression treatment, resulting in a thin portion of the fiber. An indefinite fiber is formed. As a result, in the elastic expression treatment of the stretchable sheet of the present embodiment, the nonwoven fabric is changed into a shape that is easily stretched structurally. It becomes possible to minimize the breakage of the joining points between the regular fibers and the joining points of the nonwoven fabrics 11 and 12 and the elastic filaments 13, and the strength of the stretchable sheet 10 is increased while maintaining the stretchability. can do. That is, the stretchable sheet 10 having both high elongation and high strength is obtained. Further, in the elastic expression treatment, the fact that the joints between the indefinite fibers are not easily broken also has an effect that the nonwoven fabrics 11 and 12 are less likely to become fuzzy. This is advantageous from the viewpoint of improving the appearance of the stretchable sheet 10 of the present embodiment. On the other hand, in the elastic stretchable composite sheet described in Patent Document 4 described in the section of the background art, since the constituent fibers are difficult to stretch in the stretching step, the fibers are not welded or mechanically entangled, As a result, the strength of the sheet decreases, and it is impossible to achieve both high elongation and high strength.

  Furthermore, by using the low-stretched fiber as a raw material, the number (length) of thin fibers is substantially increased as compared to before fiber stretching. Thereby, the light impermeability of the stretchable sheet 10 of the present embodiment is improved. For example, when the stretchable sheet 10 is used as a topsheet of an absorbent article such as a sanitary napkin or a disposable diaper, the body fluid absorbed by the absorbent body passes through the topsheet. This is advantageous in terms of improving the concealment performance that makes it difficult to see.

  In addition, if the region where the indefinite fiber is densely present is periodically changing on the nonwoven fabric, the surfaces of the nonwoven fabrics 11 and 12 are finely waved, and the touch is good. There is an additional effect of becoming. In this case, the period of change, that is, the distance between the thick part in the nonwoven fabric and the adjacent thick part is preferably 0.5 mm to 10 mm, particularly 2 to 5 mm. This period can be measured from microscopic observation of the nonwoven fabrics 11 and 12. The diameter of the amorphous fiber is measured by the following procedures (1) to (5).

(1) The nonwoven fabric 11 or the nonwoven fabric 12 is sampled from an area of 5 mm × 5 mm or more on the surface of the stretchable sheet 10. At this time, the sample may be collected by separating the nonwoven fabrics 11 and 12 from the elastic filament 13 or the entire stretchable sheet 10 may be collected.
(2) The collected sample is fixed to the SEM observation sample stage. At this time, in order to easily observe the sample, the sample may be fixed to the sample stage with a double-sided tape in a state where the sample is stretched to such an extent that the structure of the sample is not destroyed (until the nonwoven fabric can be loosened). The stretch amount at this time is, for example, approximately equal to or less than the stretching ratio at which the precursor of the stretchable sheet 10 is stretched in the stretching step when the step of producing the stretchable sheet 10 (elastic development treatment) is used.
(3) SEM observation is performed at a magnification of 200. The visual field area at one place is about 0.4 mm × 0.4 mm or more, and five places are observed.
(4) Fibers are extracted at random, and the diameter is measured in units of 0.1 μm at 20 or more locations every 10 μm in the fiber axis direction (fiber fusion points or broken parts are not included in the measurement. ). Four or more fibers are measured for each field, and a total of 20 fibers are measured for five fields.
(5) Extract the maximum diameter and the minimum diameter of each of the ten fibers from these values.
When the difference between the maximum diameter and the minimum diameter of one fiber is 1 μm and the relationship between the position in the fiber axis direction and the change in diameter is graphed, a fiber having a maximum position or two or more minimum positions is called an amorphous fiber.

  From the viewpoint of making the above effects even more remarkable, the indefinite fiber is preferably 2 to 15 μm in thickness at the thinnest part, more preferably 5 to 12 μm, and preferably 10 to 10 at the thickest part. It is 40 μm, more preferably 12 to 30 μm. The difference between the maximum diameter and the minimum diameter of the indefinite fiber is preferably 3 μm or more, particularly 5 μm or more, and particularly preferably 10 μm or more. Moreover, the value of the fiber diameter ratio defined by “maximum fiber diameter / minimum fiber diameter” is preferably 1 to 15, more preferably 1.2 to 10, and 2 to 5. Even more preferred.

  The non-constant fiber preferably has an inter-fiber fusion point strength higher than the strength at 100% elongation of the non-constant fiber. Thus, when the elastic sheet 10 before the elastic expression process is stretched and subjected to the elastic expression process in the elastic expression process step when the elastic sheet 10 is manufactured, the fusion point between the fibers of the elastic sheet 10 before the elastic expression process. Is less likely to occur, and the strength of the elastic sheet 10 obtained through the elastic expression treatment step is less likely to be lower than the strength of the elastic sheet 10 before the elastic expression treatment. The fusion point strength is measured according to the description in paragraph [0040] of Japanese Patent Application Laid-Open No. 2004-218183 relating to the previous application of the present applicant. The strength at 100% elongation is measured using a tensile tester under conditions of a distance between chucks of 20 mm and a tensile speed of 20 mm / min.

  The low-stretched inelastic fibers described above include both fibers drawn at a low draw ratio after spinning and unstretched fibers, that is, unstretched fibers. As the low-stretched fiber, it is preferable to use a fiber having a high elongation of 80 to 800%, particularly 120 to 650% as described above. By using a low-stretched fiber having an elongation in this range, the fiber is successfully stretched by a stretching apparatus 22 shown in FIG. 4 to be described later, and an indefinite fiber is easily formed. The fiber diameter of the low-stretched fiber is preferably 10 to 35 μm, particularly preferably 12 to 30 μm.

  As described above, the non-constant diameter fiber is preferably made from a low-stretched fiber having a constant fiber diameter as a raw material. In this case, the low-stretched fiber may be a fiber made of a single raw material, or a composite fiber using two or more raw materials, such as a core-sheath type composite fiber or a side-by-side type composite fiber. Good. Considering the ease of joining the indefinite-diameter fibers and the ease of joining the nonwoven fabrics 11 and 12 and the elastic filaments 13, it is preferable to use a composite fiber. In the case of the core-sheath type composite fiber, the core is preferably polyester (PET or PBT) or polypropylene (PP), and the sheath is preferably low melting point polyester (PET or PBT), polypropylene (PP) or polyethylene (PE). In particular, when these composite fibers are used, when the elastic filament 13 contains a polyolefin-based elastomer, thermal fusion between the elastic filament 13 and the constituent fibers of the nonwoven fabrics 11 and 12 is strong, and this is preferable because delamination hardly occurs.

  The indefinite fiber may be a short fiber such as a staple fiber or a long fiber such as a continuous filament. In view of a preferable method for manufacturing the stretchable sheet 10 described later, it is preferable to use short fibers. The indefinite fiber may be hydrophilic or water repellent.

  Each nonwoven fabric 11 and 12 may be comprised only from the indefinite diameter fiber, or in addition to the indefinite diameter fiber, the other non-elastic fiber of a fixed diameter may be contained. Other inelastic fibers include those mentioned above. When each of the nonwoven fabrics 11 and 12 includes non-elastic fibers having other fixed diameters in addition to the indefinite diameter fibers, the blending amount of the other non-elastic fibers is 1 to 30% by weight, particularly 5 to 20% by weight. Preferably there is.

  The indefinite fiber is particularly preferably contained in both of the two nonwoven fabrics 11 and 12, but may be contained only in one of the two nonwoven fabrics 11 and 12.

  As described above, the elastic filament 13 is made of, for example, an elastic resin such as a thermoplastic elastomer or rubber. In particular, when a thermoplastic elastomer is used as a raw material for the elastic resin, melt spinning using an extruder is possible in the same manner as a normal thermoplastic resin, and the filaments thus obtained are easy to heat-seal, It is suitable for the elastic sheet of this embodiment. Examples of the thermoplastic elastomer include SBS (styrene-butadiene-styrene), SIS (styrene-isoprene-styrene), SEBS (styrene-ethylene-butadiene-styrene), and SEPS (styrene-ethylene-propylene-styrene). And olefin elastomers (ethylene-based α-olefin elastomers, propylene-based elastomers copolymerized with ethylene / butene / octene), polyester-based elastomers, and polyurethane-based elastomers. These can be used individually by 1 type or in combination of 2 or more types. A core-sheath type or side-by-side type composite fiber made of these resins can also be used. In particular, use of a styrene-based elastomer, an olefin-based elastomer, or a combination thereof is preferable in terms of moldability, elastic properties, and cost of the elastic filament 13.

  A suitable combination of the elastic filament 13 and the fibers constituting the nonwoven fabric 11, 12 uses SEBS resin or SEPS resin for the elastic filament 13, and PP / PE core-sheath type composite fiber or PET / PE for the constituent fibers of the nonwoven fabric 11, 12. A combination using PE core-sheath type composite fibers. By adopting this combination, fusion can be performed firmly. Moreover, since the melting point of the core is high, the fiber is not completely melted at the time of fusion (the core remains), and the stretchable sheet 10 having a high maximum strength is obtained.

  Next, the preferable manufacturing method of the elastic sheet 10 of this embodiment is demonstrated, referring FIG. In this manufacturing method, a large number of molten elastic filaments 13 spun from the spinning nozzle 16 are drawn and stretched at a predetermined speed, and the elastic filaments 13 do not cross each other before the elastic filaments 13 are solidified. The elastic filaments 13 are fused to the nonwoven fabrics 11 and 12 so as to be arranged in one direction, and then the composite 19 to which the elastic filaments 13 are fused is subjected to an elastic expression treatment along the extending direction of the elastic filaments 13. Elasticity is imparted to the composite 19.

  The spinning nozzle 16 is provided in the spinning head 17. The spinning head 17 is connected to an extruder. Resin can also be supplied to the spinning head 17 via a gear pump. The elastic resin melt-kneaded by the extruder is supplied to the spinning head 17. The spinning head 17 has a large number of spinning nozzles 16 arranged in a straight line. The spinning nozzle 16 is arranged along the width direction of the first and second nonwoven fabrics 11 and 12. The interval between the adjacent spinning nozzles 16 corresponds to the interval between the elastic filaments 13 in the target stretchable sheet 10. The spinning nozzle 16 is usually circular, and its diameter affects the diameter of the elastic filament 13 and the draw ratio. From this viewpoint, the diameter of the spinning nozzle 16 is preferably 0.1 to 2 mm, particularly preferably 0.2 to 0.6 mm. For the purpose of increasing the bonding strength with the nonwoven fabrics 11 and 12, the purpose of increasing the spinnability of the elastic filament 13, and the purpose of improving the expansion / contraction characteristics of the elastic sheet 10, the elastic filament 13 is in a composite form (side-by-side, core sheath, sea-island structure). ). Specifically, it is preferable to combine a PP elastomer resin and a styrene elastomer resin.

  The melted elastic filaments 13 spun together with the first nonwoven fabric 11 and the second nonwoven fabric 12 that are fed from the original fabric at the same speed, and are sandwiched between the nonwoven fabrics 11 and 12 at a predetermined speed. To be picked up. The take-up speed of the elastic filament 13 coincides with the feeding speed of both the nonwoven fabrics 11 and 12. The take-up speed of the elastic filament 13 affects the diameter and the draw ratio of the elastic filament 13. The tension generated in the elastic filament 13 by stretching prevents the elastic filament 13 from being disturbed due to wind or static electricity when the elastic filament 13 is bonded to the nonwoven fabrics 11 and 12. Thereby, the elastic filaments can be arranged in one direction without crossing each other. From these viewpoints, the drawing speed of the elastic filament 13 is 1.1 to 400 times, particularly 4 to 100 times, more preferably 10 to 80 times the resin discharge speed in the spinning nozzle hole. It is preferable to adjust.

  The elastic filament 13 merges with the first and second nonwoven fabrics 11 and 12 before solidification, that is, in a state capable of being fused. As a result, the elastic filament 13 is fused to the nonwoven fabrics 11 and 12 while being sandwiched between the first and second nonwoven fabrics 11 and 12. That is, the elastic filament 13 is pulled and stretched while the elastic filament before solidification is fused to the nonwoven fabrics 11 and 12 to be conveyed. When the elastic filament 13 is fused, heat is not applied to the first and second nonwoven fabrics 11 and 12 from the outside. That is, the elastic filament 13 and the nonwoven fabrics 11 and 12 are fused only by the heat of fusion caused by the elastic filament 13 that can be fused. As a result, among the constituent fibers of both the nonwoven fabrics 11 and 12, only the fibers existing around the elastic filament 13 are fused to the elastic filament, and the fibers present at a position further away from the elastic filament 13 are not fused. As a result, since the heat applied to both the nonwoven fabrics 11 and 12 is kept to a minimum, the good texture inherent to the nonwoven fabric itself is maintained. Thereby, the texture of the stretchable sheet 10 obtained becomes favorable.

  Until the spun elastic filament 13 joins the first and second nonwoven fabrics 11 and 12, the elastic filament 13 is stretched and molecules are oriented in the stretching direction. Also, the diameter is reduced. Due to the molecular orientation, an elastic filament 13 having a small strength going / return ratio (hysteresis) at 50% elongation can be obtained. From the viewpoint of sufficiently stretching the elastic filament 13 and from the viewpoint of preventing the elastic filament 13 from being broken, a wind (hot air or cold air) of a predetermined temperature is blown onto the spun elastic filament 13 to set the temperature of the elastic filament 13. You may adjust.

  The stretching of the elastic filament 13 may be not only stretching in the molten state of the raw material resin (melt stretching), but also stretching in the softened state (softening stretching) in the cooling process. The molten state is a state in which the resin flows when an external force is applied. The melting temperature of the resin is measured as a peak temperature of Tan δ by viscoelasticity measurement (for example, measured by adding vibration strain in the rotational direction to a resin sandwiched between circular parallel plates). In order to prevent thread breakage when using an elastic resin, it is preferable to secure a long stretch section. Similarly, the melting temperature of the elastic resin is preferably 130 to 300 ° C. so that the yarn breakage does not occur. Furthermore, the melting temperature is preferably 220 ° C. or less from the viewpoint of the heat resistance of the elastic resin. The molding temperature (die temperature) of the elastic filament 13 is preferably + 50 ° C. or higher of the melting temperature of the raw material resin in order to improve the flowability of the resin and improve moldability, and is preferably + 110 ° C. or lower for heat resistance. The softening temperature is measured as the Tg temperature in the viscoelastic property of the measurement sample of the elastic resin in sheet form. The range from the softening temperature to the melting temperature is called a softened state. Moreover, the state of temperature lower than softening temperature is called solidified state. The softening temperature is preferably 60 ° C. or higher, and more preferably 80 ° C. to 180 ° C., from the viewpoint of the growth of elastic resin crystals during storage of the stretchable sheet 10 and the decrease in stretchability of the stretchable sheet 10 due to body temperature.

  The temperature of the elastic filament 13 when the elastic filament 13 and the nonwoven fabrics 11 and 12 are joined is preferably 100 ° C. or higher in order to ensure fiber fusion. More preferably, it is 120 degreeC or more, More preferably, it is 140 degreeC or more. Further, from the viewpoint of obtaining the stretchable sheet 10 having a good stretchability by maintaining the shape of the elastic filament 13, the temperature of the elastic filament is preferably 180 ° C. or lower. More preferably, it is 160 degrees C or less. As a result, the optimum filament temperature is in the range of 120 to 160 ° C, more preferably 140 to 160 ° C. The bonding temperature is observed using a film made of a modified polyethylene or a modified polypropylene having a melting point different from the melting point of the elastic resin constituting the elastic filament as a laminate base material to be bonded to the elastic filament 13. Can be measured. At this time, if the elastic filament and the laminate base material are fused, the joining temperature is equal to or higher than the melting point of the laminate base material.

  At the time of joining the elastic filament 13 and the nonwoven fabrics 11 and 12, the elastic filament 13 is substantially in a non-stretched state (a state in which it does not shrink when an external force is removed). In the bonding state between the two, at least a part of the fibers constituting the nonwoven fabrics 11 and 12 are fused to the elastic filaments, or both the elastic filament 13 and at least a part of the fibers constituting the nonwoven fabrics 11 and 12 are used. It is more preferable to fuse. This is because sufficient bonding strength can be obtained. The stretch properties of the resulting stretchable sheet 10 are affected by the density of the joint points between the elastic filament 13 and the nonwoven fabrics 11 and 12. In addition, the expansion / contraction characteristics can be adjusted by the joining temperature, the joining pressure, and the detachment of the joining point by the elastic expression treatment of the nonwoven fabrics 11 and 12 described later. By bonding the constituent fibers of the nonwoven fabrics 11 and 12 to the elastic filament 13, the bonding strength of each bonding point increases. Lowering the density of the joining points is preferable because the stretch inhibition by the nonwoven fabrics 11 and 12 is reduced and the stretch sheet 10 having sufficient joint strength is obtained.

  When the elastic filament 13 is merged with the first and second nonwoven fabrics 11 and 12, the elastic filaments 13 are arranged in one direction without crossing each other. Then, the elastic filament 13 is joined with the first and second nonwoven fabrics 11 and 12, and the elastic filament 13 is sandwiched between the nonwoven fabrics 11 and 12, and the three are sandwiched by a pair of nip rolls 18 and 18. Press. The condition of the clamping pressure affects the texture of the stretchable sheet 10 obtained. If the pinching pressure is too large, the elastic filament 13 is likely to bite into both the nonwoven fabrics 11 and 12, and the texture of the stretchable sheet 10 obtained due to this tends to be lowered. From this point of view, the clamping pressure by the nip rolls 18 and 18 is sufficient so that the elastic filament 13 contacts both the nonwoven fabrics 11 and 12, and an excessively high clamping pressure is not required.

  Another condition for the clamping pressure by the nip roll 18 is the temperature of the nip roll 18. As a result of the study by the present inventors, it is better not to heat the nip roll 18 in a heated state (that is, to leave it to the result), or to perform the pressing while cooling, a better texture. It was found that the elastic sheet 10 was obtained. When cooling the nip roll 18, it is preferable to use a coolant such as cooling water and adjust the temperature so that the surface setting temperature of the nip roll 18 is 10 to 50 ° C.

  In this way, a composite 19 in which the elastic filament 13 is sandwiched between the two nonwoven fabrics 11 and 12 is obtained. When the nonwoven fabrics 11 and 12 that are inherently extensible are used, the composite 19 becomes the stretchable sheet 10 itself. On the other hand, when the nonwoven fabrics 11 and 12 that do not inherently have extensibility are used, the composite 19 including the nonwoven fabrics 11 and 12 is elastically treated along the direction in which the elastic filament 13 extends, An operation of imparting stretchability to the composite 19 is performed. In the present manufacturing method, this operation is performed using an elastic expression processing device 22 having a pair of tooth space rolls 20 and 21 in which teeth and roots are alternately formed in the circumferential direction, and the composite 19 is moved in the conveying direction. That is, it is performed by performing an elastic expression process along the extending direction of the elastic filament 13.

  The elastic expression processing device 22 has a known lifting mechanism (not shown) for vertically displacing the pivot portion of one or both of the tooth gap rolls 20 and 21, and the interval between the tooth gap rolls 20 and 21 can be adjusted. It has become. In this manufacturing method, each tooth gap roll 20 and 21 is inserted freely between the teeth of one tooth gap roll 21 and the tooth of the other tooth gap roll 21 is one tooth. It combines so that it may be loosely inserted between the teeth of the groove roll 20, and the composite body 19 is inserted between the both tooth groove rolls 20 and 21 of the state, and this is elastically processed.

  In the elastic expression processing device 22, both the pair of tooth groove rolls 20 and 21 may be driven by a driving source (co-rotating roll), and only one tooth groove roll 20 or 21 is driven by the driving source. In this manufacturing method, only the lower tooth gap roll 21 is driven by the drive source, and the upper tooth groove roll 20 is connected to the drive source. Instead, it is driven (rotated) as the tooth gap roll 21 rotates. The use of the accompanying roll is that the high basis weight portion 14 and the low basis weight portion 15 are likely to appear clearly and striped on the stretchable sheet 10 after the elastic expression treatment, and the design of the stretchable sheet 10 is improved. The low basis weight part 15 is preferable in that the basis weight is lower and the air permeability is improved. As the tooth profile of the tooth gap rolls 20 and 21, a general involute tooth profile and a cycloid tooth profile are used, and those having a narrowed tooth width are particularly preferable.

  FIG. 5 schematically shows a state in which the composite 19 is subjected to an elastic expression process. When the composite 19 passes between the tooth gap rolls 20 and 21, the composite 19 is in a region that contacts the teeth 23 and 24 of the tooth gap rolls 20 and 21 (between P 3 and P 2 and between P 1 and P 4). Is hardly stretched. On the other hand, in the region (between P2 and P1) pressed toward the tooth surface of the tooth 23 of the tooth space roll 20 that is the driven roll by the tooth surface of the tooth 24 of the tooth space roller 21 that is the driving roll. The two teeth 20 and 21 are greatly stretched. Further, in the region (between P4 and P3) that is separated from the tooth 23 of the tooth space roll 20 by the tip of the tooth 24 of the tooth space roll 21, it is not as large as the region (between P2 and P1), but is greatly stretched. The

  The composite 19 is hardly stretched as described above in the region (between P3 and P2 and between P1 and P4) in contact with the tips of the teeth 23 and 24 of the tooth gap rolls 20 and 21, but the teeth 23 and 24 are as described above. Is pushed in the radial direction, that is, in the thickness direction of the composite 19, so that it becomes thinner in the thickness direction. However, because the region (between P3 and P2) and the region (between P1 and P4) are in the opposite direction, the thinning direction is the opposite direction.

  The stretching process can efficiently stretch both the nonwoven fabrics 11 and 12 in the composite body 19 while preventing the elastic filament 13 and the nonwoven fabrics 11 and 12 from being peeled off, thereby imparting stretchability to the composite body 19. it can. And the area | region (between P2-P1 and between P4-P3) extended | stretched greatly becomes the low basic weight part 15, and the area | region (between P3-P2 and between P1-P4) hardly extended becomes the high basic weight part 14.

  In particular, when the non-woven fabrics 11 and 12 include low-stretched fibers, the fibers are stretched and thinned between (P2-P1) and (P4-P3) described above, and the thickness thereof is periodic. An indefinite-diameter fiber that has been changed to is formed. The stretching of the low-stretched fibers varies depending on the distance between (P2-P1) and (P4-P3).

  The stretching force by the tooth gap rolls 20 and 21 mainly acts on the stretching of the low-stretched fiber, and no excessive force is applied to the joint portion between the nonwoven fabrics 11 and 12 and the elastic filament 13. As a result, the composite 19 can be efficiently stretched while preventing breakage of the bonded portion and occurrence of peeling between the nonwoven fabrics 11 and 12 and the elastic filament 13. Further, as shown in FIG. 6, by this stretching, the non-woven fabrics 11 and 12 are sufficiently stretched without breaking the bonding between the fibers, whereby the non-woven fabrics 11 and 12 inhibit the free expansion and contraction of the elastic filaments 13. The degree is greatly reduced. As a result, according to this production method, the stretchable sheet 10 having high strength and high stretchability and having a good appearance with little tearing and fluffing can be efficiently produced. In FIG. 6, the thickness of the inelastic fiber generated by stretching is uniformly expressed for convenience.

  As described above, when the nonwoven fabrics 11 and 12 include low-stretched fibers, the fibers are successfully stretched, and the joint between the fibers is not broken by stretching. The decrease in strength is minimized. Specifically, the ratio of the tensile strength of the stretchable sheet 10 obtained after the elastic expression treatment to the tensile strength of the composite 19 before the elastic expression treatment is 0.3 to 0.99, particularly 0.5 to 0.99. Furthermore, it becomes a value close to 1 of 0.7 to 0.99. The tensile strength here is measured according to the maximum strength measuring method described below.

<Measurement of maximum strength>
A rectangular test piece was cut out in a size of 200 mm in the direction of expansion and contraction of the stretchable sheet 10 and 50 mm in a direction perpendicular thereto. The distance between chucks was 150 mm. The test piece was extended at a speed of 300 mm / min in the expansion / contraction direction of the elastic sheet 10, and the load at that time was measured. The load at the maximum point at that time was defined as the maximum strength. By the same method, the maximum strength of the composite 19 before the elastic expression treatment was also measured. The maximum strength is measured using a tensile tester AG-1kNIS manufactured by Shimadzu Corporation under the conditions of a measurement environment of 20 ± 2 ° C. and a humidity of 65 ± 5% RH.

  The composite body 19 is elastically treated by the pair of tooth space rolls 20 and 21, whereby the intended stretchable sheet 10 is obtained. After the obtained elastic sheet 10 passes through the tooth gap rolls 20 and 21, the stretched state in the MD direction is quickly released by its own contraction restoring force. As a result, the length of the stretchable sheet 10 is generally restored in the transport direction. Thereby, in the extended state, the high basis weight portions 14 and the low basis weight portions 15 are alternately arranged in the extending direction of the elastic filaments 13. When the stretched state is released, the stretched state may be completely released, or the stretched state may be released in a state where a certain stretched state is maintained as long as stretchability is exhibited.

  By the elastic expression processing, the thickness of the stretchable sheet 10 is preferably 1.1 to 4 times, particularly 1.3 to 3 times the thickness of the composite 19 before the elastic expression processing. . As a result, the constituent fibers of both nonwoven fabrics 11 and 12 are plastically deformed and stretched to make the fibers thinner. At the same time, both the nonwoven fabrics 11 and 12 become more bulky, have a good touch, and have good cushioning properties.

  The stretchable sheet 10 thus obtained is stretched 100% along the direction in which the elastic filament 13 extends, and a load A (hereinafter also referred to as 50% return strength) when the stretched sheet 10 is returned by 50% from the state is elastic. It is sufficient that the ratio (A / B) to the load B (hereinafter also referred to as 50% strength) when extending 50% along the direction in which the filament 13 extends is 50% or more, particularly 65% or more. It is preferable from the viewpoint of the development of various stretch properties.

Moreover, although it also depends on a specific use, the stretch sheet 10 preferably has an overall basis weight of 10 to 150 g / m ² , particularly 25 to 60 g / m ² . Regarding the thickness of the stretchable sheet 10, it is preferably 0.05 to 5 mm, particularly preferably 0.5 to 2 mm. The thickness of the stretchable sheet 10 is measured by the same method as the measurement of the thickness of each of the nonwoven fabrics 11 and 12 described above.

The stretchable sheet 10 of this embodiment is suitably used as an outer packaging material of a pants-type disposable diaper. In addition to this application, taking advantage of its good texture, fuzz prevention, stretchability, breathability, etc., it can also be used for various uses such as medical disposable clothing, cleaning sheets, eye patch, mask, bandage, etc. . In particular, it is preferably used as a constituent material of absorbent articles such as sanitary napkins and disposable diapers. Examples of the constituent material include a liquid-permeable sheet (including a surface sheet and a sublayer) positioned on the skin side of the absorbent body, a sheet constituting an outer surface of a disposable diaper, a waistline portion, a waist portion, and a leg. Examples thereof include a sheet for imparting elastic stretchability to the surrounding portion and the like. It can also be used as a sheet or the like for forming a napkin wing. Moreover, even if it is another site | part, it can be used for the site | part etc. which want to provide a stretching property. The basis weight and thickness of the stretchable sheet 10 can be appropriately adjusted according to the specific application. For example, when used as a constituent material of an absorbent article, it is desirable that the basis weight is about 20 to 60 g / m ² and the thickness is about 0.5 to 1.5 mm.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the expansion and contraction of the above-described embodiment, a large number of elastic filaments 13 are sandwiched between the two nonwoven fabrics 11 and 12, but instead, a large number of elastic filaments are formed on the surface of one nonwoven fabric. May be joined to form an elastic sheet.

  Moreover, in the said embodiment, since all the elastic filaments 13 were arrange | positioned with the same diameter and equal pitch, the elongation stress was the same even if it took any part of the elastic sheet 10. FIG. However, instead of this, the stretchable sheet may be configured to be composed of two or more regions having different extension stresses in the extension direction of the elastic filament. Two or more of the regions are arranged substantially in parallel with the extending direction. In this case, the pitches of the adjacent elastic filaments are different and / or the diameters of the elastic filaments are different between the regions having different elongation stresses. Thereby, the elongation stress can be made different between the regions. Even when two or more kinds of different resins are introduced into an arbitrary spinning nozzle and spun during the production of the stretchable sheet, the elongation stress can be made different between the regions.

  The elastic sheet 10 can be partially embossed, or the elastic filament 13 can be partially cut or partially heat sealed. These operations are performed for the purpose of forming a non-expandable portion in the stretchable sheet 10 or partially increasing the strength. Alternatively, it is performed for the purpose of bonding with other members or providing design.

  Moreover, regarding the elastic expression processing performed after the elastic filament 13 is joined to the nonwoven fabrics 11 and 12, the elastic expression processing direction may be not only the flow direction of the nonwoven fabrics 11 and 12, but also an oblique direction, for example. Furthermore, it is possible to combine two or more kinds of elastic expression treatment methods, increase the draw ratio stepwise, or partially perform the elastic expression treatment. The elastic development processing direction may be not only one direction but also two orthogonal directions. A non-woven fabric that expands and contracts in one direction and a non-woven fabric that expands and contracts in a direction perpendicular to the non-woven fabric can be joined to give stretchability in all directions of the stretchable sheet.

  Moreover, in the manufacturing method of the said embodiment, although the elastic expression processing apparatus provided with a pair of tooth space rolls 20 and 21 was used for the elastic expression processing of the composite body 19, it replaced with this, and the elastic expression processing provided with the tenter You may perform an elastic expression processing process using an apparatus.

  Furthermore, in the above manufacturing method, as another method of joining the elastic filament 13 and the nonwoven fabrics 11 and 12, the elastic filament 13 can be directly extruded onto one nonwoven fabric without being melted and stretched directly. The draw ratio in this case is 1 time. Moreover, before joining the elastic filament 13 and the nonwoven fabrics 11 and 12, an adhesive can be supplementarily applied to the nonwoven fabric or the elastic filament, and then the elastic filament can be bonded together in a substantially unstretched state. Further, after the elastic filament 13 and the nonwoven fabrics 11 and 12 are stacked without applying an adhesive, heat treatment (spraying hot air using an air-through method, steam jet, heat embossing), mechanical entanglement (needle punch, span) Race). At this time, a fiber web can be used on one side or both sides instead of the nonwoven fabric.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples.

[Example 1]
The stretchable nonwoven fabric having the structure shown in FIGS. 1 and 2 was manufactured using the apparatus shown in FIG. As the first and second nonwoven fabrics 11 and 12, air-through nonwoven fabrics having a basis weight of 15 g / m ² were used. The constituent fiber of this nonwoven fabric was a core-sheath type composite fiber (core: PET, sheath: PE) having a diameter of 19 μm, a maximum elongation of 180%, and a fiber length of 44 mm. An elastomer made of SEPS resin (weight average molecular weight 50,000, MFR 60 g / 10 min (230 ° C., 2.16 kg) (JIS K7210: 1999)) was used as the raw material resin for the elastic filament 13. The spinning conditions were as follows. The temperature was 310 ° C., the diameter of the spinning nozzle 16 was 400 μm, and the pitch of the spinning nozzle 16 was 1 mm, the diameter of the elastic filament 13 was 120 μm, the apparent basis weight (filament weight / sampling sheet area in the sample) was 10 g. / M ² , the draw ratio was 11. The draw ratio is defined by (nozzle hole diameter / fiber diameter before expansion / development treatment) ^{2. The} elastic development treatment is performed by alternating teeth and roots in the axial length direction. It performed using the elastic expression processing apparatus 22 provided with a pair of formed tooth space rolls 20 and 21. The pitch between teeth and between tooth bottoms. (The pitch P between teeth in the engaged state is 1.0 mm.) The amount of pushing of the upper and lower tooth gap rolls is adjusted, and the composite 19 at a draw ratio of 3.0 times Was elastically treated in the direction in which the elastic filament 13 extends, whereby an elastic sheet 10 having a basis weight of 40 g / m ² that expands and contracts in the direction in which the elastic filament 13 extends was obtained. In addition, a striped pattern caused by the elastic filament 13 was presented, and a striped pattern caused by the high basis weight region and the low basis weight region was also exhibited. The elastic filament 13 in the stretchable sheet 10 has an elliptical cross section having a major axis in the plane direction of the sheet 10, and the ratio of major axis / minor axis was 1.6. .1 The width at the time of 5-fold elongation was 96% of the original, and the width shrinkage was 4% .The constituent fibers of the nonwoven fabrics 11 and 12 in the stretchable sheet 10 had a uniform thickness along the longitudinal direction of the fibers. It was confirmed by microscopic observation that the constituent fibers had a maximum fiber diameter of 26.1 μm, a minimum fiber diameter of 6.8 μm, and a fiber diameter ratio of 3.8. The fiber diameter varied periodically within this range.

[Example 2]
The pitch of the spinning nozzles 16 was set to 1 mm in the width direction of the spinning head 17 to form a first nozzle row. Furthermore, a second nozzle row was formed at the same pitch as the first nozzle row at a position 1 mm away from the first nozzle row in the flow direction of the spinning head 17. The first nozzle row and the second nozzle row were arranged so as to be shifted from each other by a half pitch. Moreover, the draw ratio of the elastic filament 13 was changed to 25 times to make the diameter of the elastic filament 13 80 μm. Except for these, the stretchable sheet 10 was obtained in the same manner as in Example 1. In this stretchable sheet 10, the pitch of the elastic filaments 13 was 0.5 mm.

Example 3
The nozzle diameter of the spinning nozzle 16 is set to 400 μm, the stretch ratio of the elastic filament 13 is set to 11 times, and the diameter of the elastic filament 13 is set to 120 μm, and the nozzle diameter of the spinning nozzle 16 is set to 300 μm. In addition, a second region was formed in which the stretch ratio of the elastic filament 13 was set to 18 and the diameter of the elastic filament 13 was set to 70 μm. Except for these, the stretchable sheet 10 was obtained in the same manner as in Example 1. The first region and the second region were arranged in parallel in the width direction of the stretchable sheet 10. The diameters of the two types of elastic filaments having different thicknesses in the stretchable sheet 10 were measured separately.

Example 4
Except that the styrene-based elastomer used in Example 1 was dry blended with 1.5% by weight of a purple colored masterbatch compound (PE resin base, pigment concentration 60% by weight) and the purple elastic filament 13 was used. In the same manner as in Example 1, an elastic sheet 10 was obtained. In this stretchable sheet, the striped pattern due to the elastic filament 13 was more prominent over the nonwoven fabric.

Example 5
After heat-treating the composite 19 used in Example 1 by blowing hot air by an air-through method, the elastic sheet 10 was obtained by subjecting it to elastic expression treatment under the same conditions as in the Example. In this stretchable sheet, the fibers of the nonwoven fabrics 11 and 12 were fused together, and a sheet having higher bonding strength was obtained.

[Comparative Example 1]
An elastic sheet was produced according to the method described in Patent Document 1. That is, an elastic net (basis weight 73 g / m ² ) of CONWED was used, and air-through nonwoven fabrics having a basis weight of 20 g / m ² were used as the first and second nonwoven fabrics 11 and 12. The constituent fiber of this nonwoven fabric was a core-sheath type composite fiber (core: PET, sheath: PE) having a diameter of 17 μm, a maximum elongation of 30%, and a fiber length of 44 mm. The lattice of the stretchable net was generally square with respect to the MD direction of the nonwoven fabrics 11 and 12. (MD direction and CD direction are both 3.2 mm). Using a metal press machine heated to 120 ° C. and 70 ° C., these were heat / pressure bonded for 10 seconds at a pressure of about 10 kg / cm ² . The obtained sheet is provided with a pair of concavo-convex rolls having a large diameter portion and a small diameter portion alternately formed in the axial direction (a pitch P between teeth in a meshed state is 1.0 mm). Was used for elastic expression treatment. Since the constituent fibers of the nonwoven fabric do not stretch, a phenomenon that holes are formed in the nonwoven fabric when the stretch ratio of the elastic expression treatment is high was observed. Therefore, the stretching ratio in the MD direction was 2.7 times. The degree of stretching was controlled by adjusting the pushing amount of the upper and lower concavo-convex rolls. Since the obtained stretchable sheet was difficult to stretch, the width shrinkage increased. In addition, the feeling of the elastic net was felt and the texture was inferior.

[Comparative Example 2]
In the same manner as in Comparative Example 1, a stretch sheet was obtained using a stretch net (basis weight 55 g / m ² ) manufactured by CONWED. The lattice of the stretchable net was generally diamond-shaped with respect to the MD direction of the nonwoven fabrics 11 and 12 (9.5 mm in both the MD direction and the CD direction). Using metal press machines heated to about 120 ° C. and about 60 ° C., respectively, these were heat / pressure bonded at a pressure of about 10 kg / cm ² for 10 seconds. The obtained sheet is provided with a stretching device (elasticity) provided with a pair of concavo-convex rolls (a pitch P between teeth in a meshed state is 1.0 mm) in which large diameter portions and small diameter portions are alternately formed in the axial direction. Using an expression processing apparatus, the film was stretched 3.0 times in the MD direction and subjected to an elastic expression process. Since the nonwoven fabric fibers did not stretch in the obtained stretchable sheet, many holes were opened in the nonwoven fabric during the elastic expression treatment. For this reason, the entire sheet was thick, but the joint between the elastic net and the nonwoven fabric was hard. As a result, it was inferior in terms of texture.

[Evaluation]
About the expansion-contraction sheet | seat obtained by the Example and the comparative example, 50% return strength / 50% going strength and texture were measured and evaluated by the following methods. Moreover, the thickness of the expansion-contraction sheet | seat and the nonwoven fabric was measured by the above-mentioned method. The results are shown in Table 1 below.

[50% return strength / 50% strength]
The elastic sheet was cut out in a size of 200 mm in the direction of expansion and contraction and 50 mm in a direction perpendicular to the expansion / contraction direction to obtain a test piece. A test piece was attached to a tensile tester AG-1kNIS manufactured by Shimadzu Corporation at a distance between chucks of 150 mm. The test piece was stretched in the stretching direction at a speed of 300 mm / min. The load at the time of 50% elongation was recorded, and the value was taken as 50% strength. Subsequently, the test piece was stretched to 100% and then shrunk at the same speed in the return direction (shrinking direction) to be stretched by 50%. The load at that time was recorded, and the return strength was 50%. The above measurements were performed in an environment of temperature 20 ± 2 ° C. and humidity 65 ± 5% RH.

[Texture]
Ten female monitors were allowed to evaluate the texture of the stretchable sheet in a dark box where the stretchable sheet was not visible in an environment of temperature: 25 ° C. and humidity: 40%. According to the evaluation of each monitor, the following score was given, and the average score (rounded off the decimal point) of 10 monitors was used as the evaluation score of the texture.
5 points: The texture is good.
4 points: The texture is slightly good.
3 points: Normal.
2 points: The texture is slightly bad.
1 point: The texture is bad.

  As is clear from the results shown in Table 1, it can be seen that the stretchable sheet of each example has better stretchability than the stretchable sheet of the comparative example. Moreover, it turns out that it has thickness and has a favorable texture. Furthermore, in the stretchable sheet of each example, the elastic filaments were arranged so as not to cross each other and contact each other. On the other hand, the elastic sheet of Comparative Example 1 was crushed by the press and the net was conspicuous, the net was glossy, and the appearance was not good.

FIG. 1 is a partially broken perspective view showing an embodiment of the stretchable sheet of the present invention. 2A and 2B are longitudinal sectional views in a natural state and an extended state, respectively, along the extending direction of the elastic filament in the stretchable sheet shown in FIG. FIG. 3 is an SEM image showing an example of an inelastic fiber in which the diameter (cross-sectional area) of the fiber is changed in a substantially step shape. FIG. 4 is a schematic view showing an apparatus suitably used for manufacturing the stretchable sheet shown in FIG. FIG. 5 is a schematic view showing a state in which the composite is subjected to an elastic expression treatment by the apparatus shown in FIG. FIG. 6 is a schematic diagram showing a state where the non-elastic fiber is subjected to an elastic expression process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Elastic sheet 11 1st nonwoven fabric 12 2nd nonwoven fabric 13 Elastic filament 14 High basic weight area | region 14 'Top part 14 "Valley part 15 Low basic weight area | region 15' Ridge line part

Claims (14)

An elastic sheet in which a large number of elastic filaments arranged to extend in one direction without crossing each other are joined to an extensible nonwoven fabric over their entire length in a substantially non-extended state,
The elastic filament is formed by stretching an elastic resin in a melted or softened state,
A stretchable sheet, wherein the stretchable nonwoven fabric includes inelastic fibers whose thickness along the longitudinal direction of the fibers is not uniform.   The elastic sheet according to claim 1, wherein the elastic filament is bonded to the nonwoven fabric by fusion bonding. The stretchable sheet according to claim 1 or 2 , wherein the elastic filament is obtained by melting and stretching an elastic resin spun from a spinning nozzle. The elastic filaments are those wherein the elastic resin is obtained by being stretched to 1.1 to 400 times in a state of being melted or softened, to any of 3 to the claims 1 has become 10~200μm diameter The elastic sheet as described. In the stretch sheet, the elastic tensile stress in the elongation direction of the filaments Ri Do different, and two or more regions where Ru extending respectively該伸length direction are substantially arranged in parallel in the width direction of the stretch sheet, between each region The stretchable sheet according to any one of claims 1 to 4 , wherein the pitches of the adjacent elastic filaments are different and / or the diameters of the elastic filaments are different. The elastic sheet according to any one of claims 1 to 5 , wherein the elastic filament is sandwiched between two identical or different nonwoven fabrics. The elastic sheet according to any one of claims 1 to 6 , wherein an average flatness ratio of the elastic filament is 1.0 to 7.0 times. The stretchable sheet according to any one of claims 1 to 7 , wherein the inelastic fiber has a thickness of 2 to 15 µm in the thinnest portion and 10 to 30 µm in the thickest portion. The stretchable sheet according to any one of claims 1 to 8 , wherein the inelastic fiber is a short fiber made of a composite fiber. The stretchable sheet according to any one of claims 1 to 9 , wherein the inelastic fiber raw material has an elongation of 80 to 800%. An elastic sheet in which a large number of elastic filaments arranged so as to extend in one direction without crossing each other are bonded to an extensible nonwoven fabric over their entire length in a substantially non-extended state. The nonwoven fabric is a method for producing a stretchable sheet containing inelastic fibers whose thickness along the longitudinal direction of the fibers is not uniform ,
A plurality of molten elastic filaments spun from a spinning nozzle are drawn and stretched at a predetermined speed, and before the elastic filaments are solidified, the elastic filaments are arranged in one direction without crossing each other. A method for producing a stretchable sheet, in which a composite is bonded to a non-woven fabric, and then the elastic filament is fused, and elastic treatment is performed along the direction in which the elastic filament extends to impart stretchability to the composite. The method for producing a stretchable sheet according to claim 11 , wherein the elastic filament is taken and stretched by fusing the elastic filament to the conveyed nonwoven fabric. The stretch is imparted in the flow direction of the composite by passing the composite along a flow direction between a pair of tooth space rolls in which teeth and tooth bottoms are alternately formed in the circumferential direction. The manufacturing method of the elastic sheet of 11 or 12 . An elastic sheet in which a large number of elastic filaments arranged to extend in one direction without crossing each other are joined to an extensible nonwoven fabric over their entire length in a substantially non-extended state,
In the stretch sheet, the elastic tensile stress in the elongation direction of the filaments Ri Do different, and two or more regions where Ru extending respectively該伸length direction are substantially arranged in parallel in the width direction of the stretch sheet, between each region An elastic sheet in which the pitches of the adjacent elastic filaments are different and / or the diameters of the elastic filaments are different.