JP6581863B2 - Stretchable sheet manufacturing method and spinning device - Google Patents

Description

  The present invention relates to a method for producing an elastic sheet that is a composite of elastic fibers and a sheet material such as a nonwoven fabric, and a spinning device that can be used in the production method.

  The stretch sheet has good stretchability, texture, breathability, etc., taking advantage of its properties, such as absorbent articles such as sanitary napkins and disposable diapers, medical disposable clothing, cleaning sheets, eye patches, masks, bandages, etc. It is used for various purposes. With respect to such an elastic sheet, for example, Patent Document 1 describes an elastic sheet having a configuration in which a plurality of elastic filaments are bonded to a nonwoven fabric and the plurality of elastic filaments are arranged so as to extend in one direction without crossing each other. Has been. The stretchable sheet described in Patent Document 1 is manufactured using a so-called melt spinning method, and specifically, melted elastic resin is spun from a plurality of nozzles provided on the lower end surface of the spinning head, and melted. Alternatively, a plurality of elastic filaments in a softened state are obtained, and the plurality of elastic filaments are manufactured through a process of drawing and stretching at a predetermined speed and fusing to a sheet material before solidifying. Patent Document 1 describes the arrangement of nozzles of a spinning head used in such a manufacturing method, in which a number of nozzles are linearly arranged in a row in the spinning head ([0056 of Patent Document 1]. 〕reference)

  Patent Document 2 describes a net-like structure that can be used as a cushioning material used for furniture, beds, and the like. The network structure described in Patent Document 2 distributes thermoplastic elastomer to nozzle orifices from a multi-row nozzle having a plurality of orifices, and discharges the elastomer downward from the nozzles at a predetermined melting temperature. It is manufactured through a process of forming a three-dimensional structure by bringing them into contact with each other and fusing them. In the example of Patent Document 2, it is described that the nozzles for discharging the thermoplastic elastomer have a staggered arrangement (see [0046] of Patent Document 2). The reason why the staggered arrangement of nozzles is used in the technology described in Patent Document 2 is that a plurality of melted spinning products spun from a plurality of nozzles are intentionally brought into contact with and fused to each other. This is to obtain a dimensional structure, and in the technique described in Patent Document 2, it is not assumed that a plurality of spinning products spun from a nozzle are arranged so as to extend in one direction without crossing each other.

JP 2008-179128 A Japanese Patent Laying-Open No. 2015-98654

  A method for manufacturing an elastic sheet described in Patent Document 1, that is, a method for manufacturing an elastic sheet in which a plurality of elastic filaments are joined to a sheet material, and the plurality of elastic filaments are arranged to extend in one direction without crossing each other. However, when the distance between the nozzles is narrowed, there is a problem that a plurality of filaments spun from a plurality of nozzles of the spinning head are bound to each other before being fused to the sheet material. That is, as shown in FIG. 12, in the conventional spinning head 91, a plurality of nozzles 12 are arranged in a straight line on the lower end surface 91a, and two adjacent nozzles 12, 12 in the nozzle row are arranged. The two filaments 4 and 4 spun from are crossed immediately after spinning due to unintentional shaking of the spinning head 91, the influence of airflow, etc., and as a result, are thicker than desired. In some cases, the filament 4 'was formed. The lower end surface 91a of the spinning head 91 has a small pitch portion 93 having a relatively small nozzle pitch (a distance between the centers of adjacent nozzles) and a large pitch portion 94 having a relatively large nozzle pitch. Such a filament binding phenomenon is more likely to occur as the nozzle pitch is smaller, and is particularly likely to occur at the small pitch portion 93 in the spinning head 91.

  Such binding of filaments immediately after spinning from the nozzle adversely affects the appearance, handleability, and the like of the stretchable sheet, which is the production object. For example, when only a part of a plurality of filaments in the stretchable sheet has a large diameter due to the binding between the filaments, the stretchable sheet has a relatively small diameter relative to a relatively thin filament. When a thick filament is mixed, the stretch sheet roll wound around the roll by winding the stretch sheet has irregularities due to unevenness of the filament diameter on the roll peripheral surface. The shape of the roll as a whole is distorted, and therefore there is a risk that troubles may occur in operations such as winding and unwinding of the roll.

  Further, since the wall material forming the nozzle installation surface (lower end surface) of the spinning head is pressurized when supplying the molten resin to the spinning head, pressure resistance that is not damaged by the pressure is required. When a plurality of nozzles are formed in a straight line in a wall material, the pressure resistance of the wall material tends to decrease as the nozzle pitch decreases. On the other hand, there are various demands for the arrangement of the filaments in the stretchable sheet, and a filament having a relatively small pitch is also demanded. However, no technology that can meet such demands has yet been provided.

  Therefore, the subject of this invention is related with providing the manufacturing method and spinning apparatus of an elastic sheet which can manufacture efficiently the elastic sheet which is excellent in the handleability with high quality.

  The present invention relates to a method for manufacturing an elastic sheet, in which a plurality of elastic filaments are joined to a sheet material, and the plurality of elastic filaments are arranged so as to extend in one direction without crossing each other, and the melted elasticity The resin is spun from a plurality of nozzles provided on the lower end surface of the spinning head to obtain a plurality of molten or soft elastic filaments, and the plurality of elastic filaments are drawn and stretched at a predetermined speed before being solidified. The lower end surface of the spinning head has a staggered arrangement portion in which a plurality of the nozzles are arranged in a staggered manner, and in the staggered arrangement portion, the plurality of nozzles are A plurality of nozzle rows arranged at a predetermined interval in one direction are arranged in a direction orthogonal to the one direction, and the adjacent nozzle rows in the direction orthogonal to the one direction And the nozzle is shifted from each other, there is provided a method for producing a stretch sheet.

  The present invention is also a spinning device including a spinning head that spins molten resin from a nozzle to form a melted or softened filament, and a plurality of the nozzles are arranged in a staggered manner on the lower end surface of the spinning head. In the zigzag arrangement portion, a plurality of nozzle rows in which the plurality of nozzles are arranged at a predetermined interval in one direction are arranged in a direction orthogonal to the one direction, and The present invention provides a spinning device in which the nozzles are displaced from each other in adjacent nozzle rows in a direction orthogonal to one direction.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method and spinning apparatus of an elastic sheet which can manufacture efficiently the elastic sheet excellent in the handleability with high quality are provided. The elastic sheet manufactured by the elastic sheet manufacturing method or spinning apparatus of the present invention has a plurality of elastic filaments joined to the sheet material, and the plurality of elastic filaments are arranged so as to extend in one direction without crossing each other. However, according to the present invention, since the unintended crossing of the elastic filaments is unlikely to occur during the production of the elastic sheet, even when producing an elastic sheet having a relatively small pitch of elastic filaments, a high-quality elastic sheet Can be manufactured efficiently.

FIG. 1 is a perspective view schematically showing a main part of a stretchable sheet manufacturing apparatus used for carrying out an embodiment of a method for manufacturing a stretchable sheet according to the present invention. 2 is a perspective view schematically showing the lower end surface (nozzle installation surface) side of the spinning head in the manufacturing apparatus shown in FIG. FIG. 3 is a cross-sectional view schematically showing a cross section taken along line II of FIG. 2 with the lower end surface side of the spinning head drawn downward. FIG. 4 is a plan view schematically showing the arrangement of nozzles in the spinning head in the manufacturing apparatus shown in FIG. FIG. 5 is a perspective view schematically showing a state in which an elastic filament is spun from a nozzle of a spinning head in the manufacturing apparatus shown in FIG. FIG. 6 is a perspective view schematically showing a partially cutaway stretchable sheet manufactured using the manufacturing apparatus shown in FIG. FIG. 7 is a perspective view schematically showing a main part of an apparatus used for carrying out an elastic expression process in the method for producing an elastic sheet of the present invention. FIG. 8 is a plan view schematically showing a lower end surface (nozzle installation surface) in another embodiment of the spinning head according to the present invention. FIG. 9 is a plan view of the stretchable sheet manufactured using the spinning head shown in FIG. FIG. 10 is a plan view showing another embodiment of the arrangement of nozzles in the spinning head according to the present invention. FIG. 11 is a plan view showing the arrangement of nozzles in a spinning head of a comparative example. FIG. 12 is a view corresponding to FIG. 5 of a conventional spinning head.

  Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. The principal part of the manufacturing apparatus 10 of the elastic sheet used for implementation of one embodiment of the manufacturing method of the elastic sheet of this invention is shown by FIGS. FIG. 6 shows the stretchable sheet 1 manufactured by the manufacturing apparatus 10 in a partially broken state.

  As shown in FIG. 6, the stretchable sheet 1 has a configuration in which a plurality of thread-like elastic filaments 4 are joined to two sheet materials 2 and 3, and the plurality of elastic filaments 4 are not crossed with each other. They are arranged to extend in the direction. The plurality of elastic filaments 4 are sandwiched and fixed between the two sheet materials 2 and 3. As will be described later, the elastic filament 4 is formed by being stretched in a state where the elastic resin is melted or softened. Each of the plurality of elastic filaments 4 is substantially continuous over the entire length in one direction (the direction indicated by the symbol Y) of the stretchable sheet 30. As used herein, “elastic” means a property that can be stretched and contracts when released from the stretched force. 6 indicates the pitch of the elastic filament 4, that is, the distance between the centers of the adjacent elastic filaments 4 and 4. In the stretchable sheet 1, the plurality of elastic filaments 4 are arranged at an equal pitch.

  As shown in FIG. 1, the manufacturing apparatus 10 includes a spinning device including a spinning head 11 that spins a molten resin from a nozzle to form a filament 4 in a molten or softened state. This spinning device is a spinning device that prevents filaments by a so-called melt-blowing method. In addition to the spinning head 11, the spinning device includes a melt extruder (not shown) that melts an elastic resin chip and sends it to the spinning head 11. The basic configuration is the same as that of a known melt-blow spinning apparatus.

  As shown in FIGS. 2 and 3, the spinning head 11 includes a bottom wall portion 11L having a rectangular shape in plan view that forms a lower end surface 11a of the head 11, and a side wall portion 11S connected to the periphery of the bottom wall portion 11L. The interior space of the spinning head 11 defined by these wall portions 11L and 11S serves as a storage portion 13 for the molten resin supplied from the melt extruder. A plurality of nozzles 12 are formed in the lower end surface 11 a of the spinning head 11, and the storage portion 13 of the spinning head 11 communicates with the outside via each nozzle 12. The material of the spinning head 11 can be set in the same manner as known materials, and is usually a metal.

  As one of the main features of the present invention, as shown in FIGS. 2 and 4, a staggered arrangement portion 12 </ b> A in which a plurality of nozzles 12 are arranged in a staggered manner on a lower end surface 11 a that is a nozzle installation surface of the spinning head 11. The point provided is mentioned. In the staggered arrangement portion 12A, a nozzle row 12L in which a plurality of nozzles 12 are arranged at a predetermined interval in one direction, specifically, in the longitudinal direction X of the lower end surface 11a (a portion surrounded by a dotted line in FIG. 4). ) Are arranged in a direction orthogonal to the one direction, that is, in the width direction Y of the lower end surface 11a, and in the width direction Y, the nozzle rows 12L and 12L adjacent to each other in the width direction Y 12 is off.

  In other words, in the staggered arrangement portion 12A, a plurality of (two in the present embodiment) nozzle rows 12L in which a plurality of nozzles 12 are arranged at a predetermined interval in one direction (longitudinal direction X) are respectively provided. When projected in a direction (width direction Y) orthogonal to the one direction, between the projected images of the nozzles 12 in the specific nozzle row 12L (for example, two nozzles 12, adjacent in the specific nozzle row 12L, The plurality of nozzles 12 are arranged in a staggered manner so that the projected images of the nozzles 12 in another nozzle row 12L adjacent to the specific nozzle row 12L in the width direction Y are arranged at the intermediate position 12). . Note that the “staggered arrangement” in the present invention includes not only an aspect in which the plurality of nozzles 12 are perfectly arranged as described above, but also a slight unintended arrangement such as an inevitable shift in manufacturing. A mode in which deviation occurs is also included.

  As described above, in the conventional spinning head such as the spinning head 91 shown in FIG. 12, the plurality of nozzles 12 are not arranged in a staggered pattern but arranged in a straight line, so that the nozzle pitch is particularly small. In the small pitch portion 93, the plurality of elastic filaments 4 spun from the nozzle 12 are easy to bind unintentionally immediately after spinning, and therefore there is a problem that the elastic filament 4 having a desired thickness cannot be obtained. . On the other hand, in this embodiment, such a problem is solved by arranging the plurality of nozzles 12 in the spinning head 11 in a staggered manner. As shown in FIG. 5, the plurality of elastic filaments 4 spun from the plurality of nozzles 12 extend downward without crossing each other, and remain in the form of a single elastic filament 4 in the state 2 It is clamped and fixed between the sheet materials 2 and 3. Therefore, according to the manufacturing apparatus 10, even if the pitch P (see FIG. 6) of the elastic filaments 4 in the stretchable sheet 1 that is the manufacturing object is relatively small, the thickness of each elastic filament 4 is uniform, The elastic sheet 1 having high quality and excellent handleability can be produced efficiently.

  The pitch P (see FIG. 6) of the elastic filaments 4 in the stretchable sheet 1 that is the manufacturing object is determined by the substantial nozzle pitch NP (see FIG. 4) of the nozzle that spins the elastic filaments 4, and this causes a particular problem in manufacturing. Otherwise, it is usually the same as the substantial nozzle pitch NP. This substantial nozzle pitch NP corresponds to “nozzle pitch in a projected image when a plurality of nozzles on the nozzle installation surface of the spinning head are each projected in the width direction perpendicular to the longitudinal direction of the nozzle installation surface”. The nozzle pitch is the distance between the centers of two adjacent nozzles.

  For example, as shown in FIG. 11, when a plurality of nozzles 12 are arranged in a line along the longitudinal direction X of the spinning head, the substantial nozzle pitch NP is equal to two nozzles 12 adjacent in the line. , 12 is the same as the distance between the centers (nozzle pitch P1). On the other hand, the substantial nozzle pitch NP in the staggered arrangement portion 12A of the spinning head 11 is obtained when each of the two nozzle rows 12L and 12L constituting the staggered arrangement portion 12A is projected in the width direction Y as shown in FIG. This is the distance between the centers of the two adjacent nozzles 12 in the projected image. Therefore, even if the substantial nozzle pitch NP is the same in the staggered arrangement portion 12A in FIG. 4 and the one nozzle row in FIG. 11, the two nozzles 12 constituting the substantial nozzle pitch NP in the staggered arrangement portion 12A. , 12 are spaced apart from each other not only in the longitudinal direction X but also in the width direction Y. Therefore, the distance between the centers of the two nozzles 12 and 12 is longer than that of the one nozzle row in FIG. This is the main reason why the unintended crossing / binding of the elastic filaments 4 hardly occurs in the spinning head 11 having the staggered arrangement portion 12A.

  Further, in the spinning head 11, the distance between the centers of the plurality of nozzles 12 in the staggered arrangement portion 12A is relatively sufficient, and the bottom wall portion 11L surrounding each of the plurality of nozzles 12 is provided. Since there are a relatively large number of members such as metals, the spinning head 11 has a practically sufficient pressure resistance that is difficult to break at least with a normal molten resin supply pressure, and is excellent in durability of the apparatus.

  In the conventional spinning head in which a plurality of nozzles are linearly arranged in a line, such as the spinning head 91 shown in FIG. 12, the above-described problem may occur if the nozzle pitch (substantially nozzle pitch NP) is reduced. As described above, in the staggered arrangement portion 12A, even if the nozzle pitch is reduced, a problem hardly occurs. Therefore, the stretchable sheet 1 having a small pitch of the elastic filaments 4 can be efficiently manufactured. The pitch P1 (see FIG. 4) of the nozzles 12 of each of the plurality of nozzle rows 12L in the staggered arrangement portion 12A can be set to 1 mm or less, for example. On the other hand, the lower limit value of the pitch P1 depends on the material of the spinning head 11, but is about 0.2 mm if the material is a normal metal.

  Further, in the adjacent nozzle rows 12L and 12L in the staggered arrangement portion 12A, “an arbitrary one nozzle 12 in one nozzle row 12L (hereinafter referred to as a specific nozzle 12) and the specific nozzle 12 in the other nozzle row 12”. The distance between the centers of the nozzles 12 closest to (pitch P2) can be set in the same range as the pitch P1.

  In each of the plurality of nozzle rows 12L on the lower end surface 11a of the spinning head 11, the plurality of nozzles 12 are arranged at an equal pitch, that is, the pitch P1 (see FIG. 4) is uniform. In the nozzle row 12L, the pitch P1 may not be uniform.

The nozzle 12 in the spinning head 11 has a circular shape in plan view. However, in the present invention, the shape of the nozzle in plan view is not particularly limited, and may be an arbitrary shape such as a polygonal shape. The diameter of the circular nozzle 12 in plan view affects the diameter of the elastic filament 4 and the draw ratio. From this viewpoint, the diameter of the nozzle 12 is preferably 0.1 mm or more, more preferably 0.2 mm or more, and preferably 2 mm or less, more preferably 0.6 mm or less.
When the diameter of the nozzle 12 is within the above range, the nozzle pitches P1 and P2 (see FIG. 4) of the nozzle 12 are preferably 0.3 mm or less, more preferably 0.5 mm or less, and preferably Is 4.1 mm or less, more preferably 1.3 mm or less.

  The manufacturing method of the elastic sheet of this invention can be implemented as follows using the manufacturing apparatus 10, for example. As shown in FIG. 1, the elastic sheet 1 using the manufacturing apparatus 10 is manufactured by spinning molten elastic resin from a plurality of nozzles 12 provided on the lower end surface 11a of the spinning head 11, A plurality of softened elastic filaments 4 are obtained, and the plurality of elastic filaments 4 are drawn and stretched at a predetermined speed, and are fused to the sheet materials 2 and 3 before solidification.

  First, an elastic resin chip as a raw material of the elastic filament 4 is melted and kneaded by a melt extruder (not shown) connected to the spinning head 11, and the molten elastic resin is stored in the storage portion 13 (FIG. 3) in the spinning head 11. Supply). The molten elastic resin supplied in this way is spun out as a molten or soft elastic filament 4 from a plurality of nozzles 12 formed in the lower end surface of the spinning head 11, as shown in FIG. As described above, since the plurality of nozzles 12 are arranged in a staggered manner, the plurality of elastic filaments 4 spun from each nozzle 12 remain in the form of a single elastic filament 4 without crossing each other. , Extending to the joining position with the sheet materials 2 and 3.

  As shown in FIG. 1, a plurality of elastic filaments 4 in a melted or softened state are spun together with sheet materials 2 and 3 fed out at the same speed from the original fabric, and between the sheet materials 2 and 3. And is picked up at a predetermined speed. The take-up speed of the elastic filament 4 coincides with the feeding speed of both sheet materials 2 and 3. The take-up speed of the elastic filament 4 affects the diameter of the elastic filament 4 and the draw ratio. The tension generated in the elastic filament 4 by stretching prevents the elastic filament 4 from being disturbed due to wind or static electricity when the elastic filament 4 is bonded to the sheet materials 2 and 3. As shown in FIG. 6, in order to arrange the elastic filaments 4 in one direction without crossing each other, it is of course effective to adjust the take-up speed and tension of the elastic filaments 4. In the aspect, since the plurality of nozzles 12 are arranged in a staggered manner as described above, basically, the inconvenience of crossing the elastic filaments 4 hardly occurs.

  The melted or softened elastic filament 4 joins with the sheet materials 2 and 3 before solidification, that is, in a meltable state. As a result, the elastic filament 4 is fused to the sheet materials 2 and 3 while being sandwiched between the sheet materials 2 and 3. That is, the elastic filament 4 is taken and stretched by fusing the elastic filament 4 before solidification to the conveyed sheet materials 2 and 3. When the elastic filament 4 is fused, heat is not applied to the sheet materials 2 and 3 from the outside. That is, the elastic filament 4 and both the sheet materials 2 and 3 are fused only by the heat of fusion caused by the elastic filament 4 that can be fused. As a result, among the constituent fibers of both sheet materials 2 and 3, only the fibers present around the elastic filament 4 are fused to the elastic filament 4, and the fibers present at a position farther than that are not fused. As a result, since the heat applied to the sheet materials 2 and 3 is kept to a minimum, if the sheet materials 2 and 3 are, for example, nonwoven fabrics, the good texture inherent to the nonwoven fabric itself is maintained. Thereby, the texture of the stretchable sheet 1 obtained becomes favorable.

  Until the spun elastic filament 4 in the melted or softened state joins the sheet materials 2 and 3, the elastic filament 4 is stretched and molecules are oriented in the stretching direction. Also, the diameter is reduced. From the viewpoint of sufficiently stretching the elastic filament 4 and preventing yarn breakage of the elastic filament 4, wind of a predetermined temperature (hot air or cold air) is blown onto the spun elastic filament 4 to adjust the temperature of the elastic filament 4. You may do it. The stretching of the elastic filament 4 is not only stretching in the molten state (melt stretching) of the resin composition (elastic resin) constituting the elastic filament 4 but also stretching in the softened state (soft stretching) in the cooling process. May be.

  The temperature of the elastic filament 4 when the elastic filament 4 and the sheet materials 2 and 3 are joined is preferably 100 ° C. or higher in order to ensure fiber fusion. Further, from the viewpoint of obtaining the elastic sheet 1 having a good elastic property while maintaining the shape of the elastic filament 4, the temperature of the elastic filament 4 at the time of joining is preferably 180 ° C. or lower. More preferably, it is the range of 120-160 degreeC. The temperature at the time of joining, that is, at the time of joining the elastic filament 4 and the sheet materials 2 and 3 has a melting point different from the melting point of the resin composition constituting the elastic filament 4 as a laminate base material to be joined to the elastic filament 4. It can be measured by using a film made of modified polyethylene, modified polypropylene, or the like and observing the bonding state. At this time, if the elastic filament 4 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 (bonding) the elastic filament 4 and the sheet materials 2 and 3, the elastic filament 4 is substantially in an unstretched state (a state in which it does not shrink when an external force is removed). In the joint state between the two, at least a part of the constituent fibers of the sheet materials 2 and 3 are fused to the elastic filament 4, or further, the elastic filament 4 and at least a part of the constituent fibers of the sheet materials 2 and 3 More preferably, both are fused. This is because sufficient bonding strength can be obtained. The expansion / contraction characteristics of the resulting elastic sheet 1 are affected by the density of the joint points between the elastic filament 4 and the sheet materials 2 and 3. In addition to the joining temperature and the joining pressure, the expansion / contraction characteristics can be adjusted by stretching (see FIG. 7) the sheet materials 2 and 3 by an elastic expression process to be described later. By bonding the constituent fibers of the sheet materials 2 and 3 to the elastic filament 4, the bonding strength of each bonding point is increased. Lowering the density of the joining points is preferable because the expansion and contraction inhibition by the sheet materials 2 and 3 is reduced, and the expansion and contraction sheet 1 having sufficient bonding strength is obtained.

  When a plurality of elastic filaments 4 are joined with the sheet materials 2 and 3, the elastic filaments 4 are arranged in one direction without crossing each other. As shown in FIG. 1, the elastic filament 4 is joined with the sheet materials 2 and 3, and the elastic filament 4 is sandwiched between the sheet materials 2 and 3. Squeeze. The condition of the clamping pressure affects the texture of the stretchable sheet 1 obtained. If the clamping pressure is too large, the elastic filament 4 is likely to bite into both the sheet materials 2 and 3, and the texture of the stretchable sheet 1 obtained due to this tends to be lowered. From this point of view, the clamping pressure by the nip rolls 15 and 15 is sufficient to allow the elastic filament 4 to contact both the sheet materials 2 and 3, and an excessively high clamping pressure is not required.

  Another condition for the clamping pressure by the nip roll 15 is the temperature of the nip roll 15. According to the knowledge of the present inventors, it is better not to heat the nip roll 15 in a heated state (that is, to leave it to the result) or to perform the pressing while cooling. An elastic sheet 1 is obtained. When cooling the nip roll 15, 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 15 is 10 to 50 ° C.

  Through the above steps, the elastic sheet 1 shown in FIG. 6, that is, a composite sheet in which the elastic filament 4 is sandwiched and fixed between the two sheet materials 2 and 3 is obtained. However, depending on the types of the sheet materials 2 and 3, the stretchable sheet may not be obtained only by the above steps. That is, when the sheet materials 2 and 3 that are inherently extensible are used, the target stretchable sheet 1 can be obtained only by the above steps, but the sheet materials 2 and 3 are inherently extensible. In the case of using a sheet that does not have the above, it is necessary to further perform an elastic expression treatment described below on the composite sheet obtained through the above steps.

  FIG. 7 shows how the elastic expression process is implemented. The elastic development process is a process in which the elastic filament 4 is fused to the sheet materials 2 and 3, and then the sheet materials 2 and 3 are stretched in the direction in which the elastic filament 4 extends. Extensibility is imparted to the sheet materials 2 and 3 having no extensibility. The processing object of the elastic expression processing is a composite sheet 1 ′ obtained by fusing the elastic filament 4 to the sheet materials 2 and 3 obtained through the steps shown in FIG. 1.

  The elastic expression process shown in FIG. 7 uses a stretching device provided with a pair of tooth gap rolls 17 and 17 in which teeth and roots are alternately formed in the circumferential direction. The composite sheet 1 ′ is stretched along the transport direction, that is, the direction in which the elastic filament 4 extends, to become the target stretchable sheet 1. This stretching apparatus is disposed upstream of the tooth gap roll 17 in the conveying direction of the composite sheet 1 'as a means for passing the composite sheet 1' drawn from the raw fabric between the tooth gap rolls 17 and 17. A pair of nip rolls 16 and 16 and a pair of nip rolls 18 and 18 disposed downstream of the tooth gap roll 17 in the conveying direction are provided. By appropriately adjusting the speed, the degree of stretching of the composite sheet 1 ′ can be adjusted.

  The stretching device has a known lifting mechanism (not shown) for vertically displacing one or both pivotal support portions of the pair of tooth space rolls 17 and 17 so that the distance between the rolls 17 and 17 can be adjusted. Has been made. For example, a pair of tooth gap rolls 17 and 17 are combined such that one tooth is loosely inserted between the other teeth and the other tooth is loosely inserted between the one teeth. The composite sheet 1 ′ is inserted between 17 and elastically treated. Both the pair of tooth gap rolls 17 and 17 may be driven by a driving source (co-rotating roll), or only one of them may be driven by a driving source (rotating roll). As the tooth profile of the tooth gap roll 17, a general involute tooth profile and a cycloid tooth profile are used, and those having a narrowed tooth width are particularly preferable. About the said elasticity expression process, the elasticity expression process of patent document 1 can be utilized suitably.

  By the elastic expression treatment, the thickness of the stretchable sheet 1 is preferably 1.1 times to 4 times, particularly 1.3 times to 3 times the thickness of the composite sheet 1 ′ before the elastic expression treatment. As a result, the constituent fibers of both sheet materials 2 and 3 are plastically deformed and stretched to make the fibers thinner. At the same time, both the sheet materials 2 and 3 become more bulky, the touch is good, and the cushioning property is good.

  The stretchable sheet 1 manufactured by the manufacturing method of the present invention can be expanded and contracted in the same direction as the direction in which the elastic filament 4 extends (direction indicated by Y in FIG. 6) regardless of whether or not the elastic development process has been performed. It has become. The stretchability of the stretchable sheet 1 is expressed due to the elasticity of the elastic filament 4. When the stretchable sheet 1 is stretched in the same direction as the direction in which the elastic filament 4 extends, the elastic filament 4 and the sheet materials 2 and 3 extend. When the stretching of the stretchable sheet 1 is released, the elastic filament 4 contracts, and the sheet materials 2 and 3 return to the state before stretching as the contraction occurs. Moreover, in the elastic sheet 1, since there is no other elastic filament bonded in a state orthogonal to the elastic filament 4, when the elastic sheet 1 is stretched in the same direction as the direction in which the elastic filament 4 extends, The stretchable sheet 1 is stretched with almost no so-called width shrinkage that shrinks in a direction perpendicular to the stretching direction.

  The stretchable sheet 1 is stretched 100% along the direction in which the elastic filament 4 extends, and a load A (hereinafter also referred to as 50% return strength) when the elastic sheet 4 is returned by 50% and along the direction in which the elastic filament 4 extends. When the ratio (A / B) to the load B (hereinafter also referred to as 50% strength) is 50% or more, particularly 65% or more when it is stretched by 50%, sufficient expansion and contraction characteristics are exhibited. To preferred.

Depending on the specific application, the stretch sheet 1 has an overall basis weight of preferably 10 g / m ² or more, more preferably 25 g / m ² or more, and preferably 150 g / m ² or less. More preferably, it is 60 g / m ² or less. The thickness of the stretchable sheet 1 is preferably 0.05 mm or more, more preferably 0.5 mm or more, and preferably 5 mm or less, more preferably 2 mm or less. The thickness of the stretchable sheet 1 is measured as follows. That is, the thickness of the measurement target sheet can be measured by sandwiching the measurement target sheet between flat plates with a load of 0.5 cN / cm ² and measuring the distance between the flat plates.

  The diameter of the elastic filament 4 constituting the stretchable sheet 1 is not particularly limited, but is preferably 10 μm or more, more preferably 20 μm or more, from the viewpoint of the balance between the texture of the stretchable sheet 1 and the productivity of the elastic filament 4. The thickness is preferably 200 μm or less, more preferably 130 μm or less. The diameter of the elastic filament 4 is determined by the diameter of the nozzle 12.

  In addition, the pitch P of the elastic filament 4 in the stretchable sheet 1 (see FIG. 6) is such that the diameter of the elastic filament 4 is within the above range from the viewpoint of the stretchable sheet 1 exhibiting sufficient stretchability and good cloth-like texture. Is preferably 0.1 mm or more, more preferably 0.4 mm or more, and preferably 5 mm or less, more preferably 1 mm or less.

The material for forming the stretchable sheet 1 will be described. As the sheet materials 2 and 3, for example, nonwoven fabrics such as air-through nonwoven fabric, heat roll nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, and melt blown nonwoven fabric can be used. These nonwovens can be continuous filaments or short fiber nonwovens. The sheet material 2 and the sheet material 3 may be the same type or different types. As used herein, “same type of sheet material” is a sheet in which the manufacturing process of the sheet material, the type of constituent fibers of the sheet material, the fiber diameter and length of the constituent fibers, the thickness and basis weight of the sheet material, etc. are all the same. Means timber. When at least one of these is different, it is a “different sheet material”. The basis weights of the sheet materials 2 and 3 are preferably 3 g / m ² or more, more preferably 5 g / m ² or more, and preferably 100 g / m ² or less, respectively, from the viewpoints of texture, thickness, and design properties. More preferably, it is 30 g / m ² or less.

  As the constituent fibers of the sheet materials 2 and 3, for example, substantially inelastic non-elastic fibers can be used. In that case, the sheet materials 2 and 3 are stretchable fiber layers mainly composed of the inelastic fibers. Can be. Examples of such inelastic fibers include fibers made of polyester such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyamide, and the like. The constituent fibers of the sheet materials 2 and 3 may be short fibers or long fibers, and may be hydrophilic or water repellent. Moreover, a core-sheath type or side-by-side type composite fiber, a split fiber, a modified cross-section fiber, a crimped fiber, a heat-shrinkable fiber, or the like can also be used. These fibers can be used alone or in combination of two or more.

  As a preferred example of the constituent fibers of the sheet materials 2 and 3, there may be mentioned those composed of two or more components 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. In particular, the use of these composite fibers is preferable because the fusion with the elastic filament 4 becomes strong and separation between the two hardly occurs.

  The elastic filament 4 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, it can be melt-spun using an extruder in the same manner as a normal thermoplastic resin, and the elastic filament thus obtained is easily heat-sealed. 1 is suitable. Examples of the thermoplastic elastomer include styrene such as SBS (styrene-butadiene-styrene), SIS (styrene-isoprene-styrene), SEBS (styrene-ethylene-butadiene-styrene), and SEPS (styrene-ethylene-propylene-styrene). -Based elastomers, olefin-based elastomers (ethylene-based α-olefin elastomers, propylene-based elastomers copolymerized with ethylene, butene, octene, etc.), polyester-based elastomers, polyurethane-based elastomers, and the like. Two or more kinds can be used in combination.

  Hereinafter, another embodiment of the present invention will be described with reference to the drawings. Regarding other embodiments to be described later, constituent parts different from those of the above-described embodiments will be mainly described, and the same constituent parts are denoted by the same reference numerals as those of the above-described embodiments and description thereof will be omitted. For the components that are not particularly described, the description of the embodiment is applied as appropriate.

  The lower end surface 11a of the spinning head 11A shown in FIG. 8 has a non-staggered arrangement portion 12B in which a plurality of nozzles 12 are not arranged in a staggered manner in addition to the staggered arrangement portion 12A. The arrangement portion 12B is adjacent in one direction, that is, in the longitudinal direction X of the spinning head 11A. In the present embodiment, the non-staggered arrangement portion 12B includes an extended portion from the staggered arrangement portion 12A in one nozzle row 12L constituting the staggered arrangement portion 12A. That is, the non-staggered arrangement portion 12B includes one nozzle row 12L. The arrangement of the non-staggered arrangement portion 12B is not limited to this example, and may be arranged between 12L and 12L in the Y direction, for example.

  FIG. 9 shows a stretchable sheet 1A manufactured using the spinning head 11A shown in FIG. The elastic sheet 1A has a strong expansion / contraction part 5 in which a plurality of elastic filaments 4 spun from the staggered arrangement part 12A and a weak expansion / contraction in which a plurality of elastic filaments 4 spun from the non-staggered arrangement part 12B are arranged. Part 6. The strong expansion / contraction part 5 has a smaller pitch of the elastic filament 4 than the weak expansion / contraction part 6, and therefore has a higher expansion / contraction force than the weak expansion / contraction part 6. That is, the stretchable sheet 1A has non-uniform stretchability in one direction indicated by X in the drawing, that is, in the width direction orthogonal to the longitudinal direction of the stretchable sheet 1A (the direction in which the elastic filament 4 extends). The elastic filaments 4 are arranged at an equal pitch, and the stretchability in the width direction is uniform from the stretchable sheet 1 (see FIG. 6). Such an elastic sheet 1A having a plurality of parts having different elasticity in the width direction is excellent in followability with respect to the displacement of the wearer's body when used as a constituent member of a wearing article such as a disposable diaper, and has a good fit. Sex is obtained.

  The arrangement of the nozzles in the spinning head according to the present invention is not limited to the above embodiment, and can be changed as appropriate without departing from the spirit of the present invention. For example, the number of nozzle rows 12L constituting the staggered arrangement portion 12A is not particularly limited, and may be three rows as shown in FIG. 10 in addition to two rows as shown in FIG. It can also be set as above. Further, the shape of the nozzle 12 in a plan view, the nozzle pitches P1 and P2, the substantial nozzle pitch NP, and the like may be appropriately adjusted according to the use of the stretchable sheet that is the manufacturing object, and is not particularly limited.

  The stretchable sheet produced by carrying out the production method of the present invention or using the spinning device of the present invention is suitably used as, for example, 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. As a constituent material of the absorbent article, for example, a liquid-permeable sheet (including a surface sheet, a sublayer, etc.) located on the skin side of the absorbent body, a sheet constituting the outer surface of the disposable diaper, a waistline portion, and a waist And a sheet for imparting elastic stretchability to the part, the leg periphery, 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.

〔Example〕
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to such examples.

[Example 1]
The apparatus having the same configuration as the manufacturing apparatus (spinning apparatus) shown in FIG. 1 to FIG. 5 has the same configuration as the elastic sheet 1 shown in FIG. 6 and has a plurality of elastic filaments arranged at equal pitches. A sheet was produced. More specifically, a composite sheet is obtained using a spinning device having a spinning head in which all nozzles are arranged in a staggered manner, such as the spinning head 11, and the composite sheet is paired as shown in FIG. By passing an elastic expression treatment device (stretching device) having a pair of tooth gap rolls in which teeth and roots are alternately formed in the circumferential direction (actual length direction), such as the tooth gap rolls 17 and 17, The composite sheet was given stretchability, and the intended stretchable sheet was produced. The nozzle pitch and the like in the apparatus used are as shown in Table 1 below, and the materials and the like used are as follows.
Elastic filament: Styrenic thermoplastic elastomer, fiber diameter 110 μm
-Basis weight of elastic filament: 10 g / m ²
Sheet material (fiber layer): Air-through nonwoven fabric with a basis weight of 20 g / m ² consisting of a composite fiber (inelastic fiber, fiber thickness 3.3 dtex) whose core is made of PET and sheath is PE. 50 g / m ²

[Comparative Example 1]
Extensive sheets were produced in the same manner as in Example 1 except that spinning heads in which all the nozzles were arranged in a straight line as shown in FIG. 11 were used.

〔Evaluation test〕
In the examples and comparative examples, whether or not the plurality of elastic filaments spun from the nozzle are crossed and bonded before being fused to the sheet material during the production of the stretchable sheet (of the filament binding phenomenon) The presence or absence) was visually observed. Moreover, the expansion-contraction sheet manufactured by the Example and the comparative example was wound by the roll shape using the well-known winding means, and it was set as the expansion-contraction sheet roll, and the external appearance and the handleability of this expansion-contraction sheet roll were evaluated, respectively. The above results are shown in Table 1 below.
The external appearance of the elastic sheet roll is evaluated by visually observing the roll to be evaluated. When the step is not smooth on the outer peripheral surface of the roll and is substantially smooth (highest evaluation), the step is about 5 mm on the outer peripheral surface of the roll. The case where there is a mark is Δ, and the case where there is a step of 6 mm or more on the outer peripheral surface of the roll is indicated as x (minimum evaluation).
The handleability of the stretchable sheet roll is implemented by supplying the roll to be evaluated to a processing machine, and the stretchable sheet being unwound from the roll and being transported by the processing machine, that is, the direction perpendicular to the transport direction (stretching) ○ (maximum evaluation) when the deviation from the appropriate transport position in the sheet width direction is 3 mm or less, △ when the meandering exceeds 3 mm and 6 mm or less, and × when the meandering is 7 mm or more (lowest evaluation) ).

1, 1A Stretch sheet 1 'Composite sheet 2, 3 Sheet material 4 Elastic filament 5 Strong stretch section 6 Weak stretch section 10 Stretch sheet manufacturing apparatus 11, 11A, 91 Spinning head 11L Bottom wall section 11S Side wall section 12 Nozzle 12A Staggered arrangement Part 12B Non-staggered arrangement part 11a, 91a Lower end surface of the spinning head (nozzle installation surface)
15, 16, 18 Nip roll 17 Tooth groove roll

Claims (8)

A plurality of elastic filaments are joined to a sheet material, and the plurality of elastic filaments are arranged so as to extend in one direction without crossing each other,
The molten elastic resin is spun from a plurality of nozzles provided on the lower end surface of the spinning head to obtain a plurality of molten or soft elastic filaments, and the plurality of elastic filaments are drawn and stretched at a predetermined speed. , Having a step of fusing to the sheet material before solidification,
The lower end surface of the spinning head has a staggered arrangement portion in which a plurality of the nozzles are arranged in a staggered manner, and the diameter of the nozzle is 0.1 mm or more and 2 mm or less,
In the staggered arrangement portion, a plurality of nozzle rows in which a plurality of the nozzles are arranged at predetermined intervals in one direction are arranged in a direction orthogonal to the one direction, and in a direction orthogonal to the one direction, The nozzles are displaced from each other between adjacent nozzle rows,
The distance between the centers of two adjacent nozzles in the nozzle row is a pitch P1, and any one nozzle in one of the two nozzle rows adjacent in the staggered arrangement portion and the one in the other. When the distance between the centers of the nozzles closest to each nozzle is the pitch P2, the pitch P1 and P2 are 1.0 mm or more and 4.1 mm or less, respectively. A plurality of elastic filaments are joined to a sheet material, and the plurality of elastic filaments are arranged so as to extend in one direction without crossing each other,
The molten elastic resin is spun from a plurality of nozzles provided on the lower end surface of the spinning head to obtain a plurality of molten or soft elastic filaments, and the plurality of elastic filaments are drawn and stretched at a predetermined speed. , Having a step of fusing to the sheet material before solidification,
The lower end surface of the spinning head has a staggered arrangement portion in which the plurality of nozzles are arranged in a staggered manner, and a non-staggered arrangement portion in which the plurality of nozzles are not arranged in a staggered manner,
In the staggered arrangement portion, a plurality of nozzle rows in which a plurality of the nozzles are arranged at predetermined intervals in one direction are arranged in a direction orthogonal to the one direction, and in a direction orthogonal to the one direction, The nozzles are displaced from each other between adjacent nozzle rows,
The method for producing an elastic sheet, wherein the staggered arrangement portion and the non-staggered arrangement portion are adjacent in one direction of the nozzle row.   The manufacturing method of the elastic sheet of Claim 1 or 2 whose diameter of the said nozzle is 0.2 mm or more and 2 mm or less (however, except 0.2 mm).   The manufacturing method of the elastic sheet as described in any one of Claims 1-3 whose temperature of this elastic filament at the time of the confluence | merging of the said elastic filament and the said sheet material is 100 degreeC or more and 180 degrees C or less.   The method for producing an elastic sheet according to any one of claims 1 to 4, further comprising a step of stretching the sheet material in a direction in which the elastic filament extends after the elastic filament is fused to the sheet material. A spinning device comprising a spinning head that spins a molten resin from a nozzle into a molten or softened filament,
The lower end surface of the spinning head has a staggered arrangement portion in which the plurality of nozzles are arranged in a staggered manner, and a non-staggered arrangement portion in which the plurality of nozzles are not arranged in a staggered manner,
In the staggered arrangement portion, a plurality of nozzle rows in which a plurality of the nozzles are arranged at predetermined intervals in one direction are arranged in a direction orthogonal to the one direction, and in a direction orthogonal to the one direction, The nozzles are displaced from each other between adjacent nozzle rows,
The spinning device, wherein the staggered arrangement portion and the non-staggered arrangement portion are adjacent in one direction of the nozzle row. The spinning device according to claim 6, wherein the number of the nozzle rows constituting the staggered arrangement portion is three or more. The spinning device according to claim 6 or 7 , wherein the plurality of nozzles are arranged at an equal pitch in each of the plurality of nozzle rows.