JP6864502B2 - How to manufacture elastic sheet - Google Patents

Description

The present invention relates to a method for producing an elastic sheet.

A technique for imparting elasticity to a sheet material is known. For example, in Patent Document 1, a composite obtained by fusing an elastic filament and a non-woven fabric over the entire length is subjected to an elastic expression treatment (stretching) along the extending direction of the elastic filament to impart elasticity to the composite. The method of manufacturing the elastic sheet is described. In this elastic sheet, since the elastic filaments are arranged so as to extend in one direction, the elastic sheet can be extended in the extending direction of the elastic filament without causing width shrinkage. Further, it has high strength, and it is said that peeling between the elastic filament and the non-woven fabric is unlikely to occur when the elastic sheet is stretched.

Patent Document 2 describes a method for producing an elastic sheet-like composite material in which a convex portion of a flexible material (nonwoven fabric or the like) having an uneven shape is thermally bonded to an elastic strand. This manufacturing method is said to provide the flexibility to select the properties of the elastic sheet composite so that it can be manufactured at a low manufacturing cost and without major improvements in the equipment.
Patent Document 3 discloses a method for manufacturing a composite telescopic member. In this manufacturing method, a laminated body in which elastic members are arranged in an stretched state between two sheet materials is sandwiched by a sandwiching body having concave portions and convex portions to be combined with each other. At this time, due to the tension generated in the elastic member, the sheet material located between the elastic member and the convex portion and the elastic member are pressed against each other to provide the joint portion. According to this manufacturing method, it is said that a composite stretchable member having elasticity, flexibility, and fine and regular gathers that are excellent in touch can be preferably manufactured.

Japanese Unexamined Patent Publication No. 2008-179128 Special Table No. 10-501195 Japanese Unexamined Patent Publication No. 2006-27089

In the elastic sheet produced by the manufacturing method described in Patent Document 1, since the non-woven fabric and the elastic filament are adhered over the entire surface, it is difficult to achieve higher elongation without causing destruction of the non-woven fabric.
In the manufacturing method described in Patent Document 2, when the non-woven fabric and the elastic strand are joined, the contact pressure of the concave-convex roll is high, so that the bonding strength between the non-woven fabric and the elastic strand is strong and the bonded portion tends to be hard.
In the method for manufacturing a composite elastic member described in Patent Document 3, it is disclosed that the two sheet materials and the elastic member are joined by using an adhesive, and the elastic member and the sheet material are directly fused to each other. It has not been.

The present invention relates to a method for producing an elastic sheet having higher elongation and excellent flexibility.

The present invention is a method for producing an elastic sheet in which a plurality of elastic filaments are adhered to a sheet material, and the plurality of elastic filaments are arranged so as to extend in one direction without intersecting each other.
An uneven shape imparting step of imparting an uneven shape to the sheet material, and
It has an bonding step of taking over and stretching a plurality of elastic filaments in a molten or softened state, and fusing and adhering the plurality of elastic filaments to the sheet material before solidification of the plurality of elastic filaments.
Provided is a method for producing an elastic sheet in which, in the bonding step, the plurality of elastic filaments are pressed against the sheet material by the tension of each of the plurality of elastic filaments in a molten or softened state to be bonded.

According to the method for producing an elastic sheet of the present invention, an elastic sheet having higher elongation and excellent flexibility can be produced.

It is a main part perspective view which showed an example of the manufacturing apparatus preferable for carrying out the manufacturing method of the stretchable sheet of this invention. FIG. 5 is a partial cross-sectional view schematically showing a step of fusing and adhering a non-woven fabric on the front and back surfaces and an elastic filament using a pair of concavo-convex rolls having a concavo-convex shape of a tooth groove on a peripheral surface in the bonding step. It is a main part perspective view which shows an example of the stretching apparatus which stretches the stretchable sheet in one preferred embodiment of the method of manufacturing a stretchable sheet of this invention. It is a partial front view which showed an example of the meshing state of the concavo-convex roll of a stretching apparatus.

Hereinafter, the present invention will be described below with reference to the drawings based on the preferred embodiment thereof. The elastic sheet according to the present invention can be used, for example, for a portion of an absorbent article such as a diaper that requires elasticity. For example, a member constituting the waist circumference of a diaper may be mentioned.

First, an example of a preferred embodiment of the method for producing an elastic sheet of the present invention will be described with reference to FIG.
As shown in FIG. 1, the elastic sheet 50 manufactured by the present embodiment is manufactured as follows.
First, the first concavo-convex structure shaping portion 100 applies the concavo-convex shape to the first sheet material 10 made of the non-woven fabric of the first raw fabric 10A by performing the first concavo-convex shape imparting step. On the other hand, the second concavo-convex structure shaping portion 200 performs a second concavo-convex shape imparting step on the second sheet material 20 made of the non-woven fabric of the second raw fabric 20A to impart the concavo-convex shape.

The first uneven shape giving step and the second uneven shape giving step will be specifically described.
The first concavo-convex structure shaping portion 100 includes a pair of concavo-convex rolls 101 and 102 that can be meshed with each other. The pair of concave-convex rolls 101 and 102 have tooth grooves extending in the roll width direction, and large-diameter convex portions 103 and 104 serving as teeth and small-diameter concave portions 105 and 106 serving as grooves are alternately arranged in the roll circumferential direction, respectively. Has been done. The roll width direction is a direction orthogonal to the roll circumferential direction on the roll peripheral surface, and the same applies hereinafter. When the concave-convex roll 102 is used in the bonding step of the elastic filament 30 described later, it is preferably cooled. The cooling temperature when the concave-convex roll 102 is cooled is determined from the viewpoint of solidifying the plurality of elastic filaments 30 in the molten or softened state, which will be described later. The cooling temperature is preferably 50 ° C. or lower, more preferably 30 ° C. or lower. The lower limit is preferably a temperature at which the uneven roll 102 does not condense, and specifically, it is preferably 10 ° C. or higher. The above temperature is the temperature of the roll surface. By cooling to a temperature equal to or lower than this upper limit, the elastic filament is sufficiently cooled and adheres to the first sheet material and the second sheet material with an appropriate adhesive force, and an elastic sheet having a good texture can be obtained.

Further, in the first and second uneven shape imparting steps, it is preferable to perform suction to each of the uneven roll sides. Specifically, by providing a suction mechanism inside the concavo-convex roll, the concavo-convex shape can be imparted to the first sheet material 10A and the second sheet material 20A without difficulty. Thereby, it becomes possible to have a uniform uneven shape.

The second concavo-convex structure shaping portion 200 includes a pair of concavo-convex rolls 201 and 202 that can be meshed with each other. The pair of concave-convex rolls 201 and 202 have tooth grooves extending in the roll width direction, and large-diameter convex portions 203 and 204 serving as teeth and small-diameter concave portions 205 and 206 serving as grooves are alternately arranged in the roll circumferential direction, respectively. Has been done. When the concave-convex roll 202 is used in the bonding step of the elastic filament 30 described later, it is preferably cooled. The cooling of the concave-convex roll 202 is the same as the cooling of the concave-convex roll 102.

Along with each of the above-mentioned uneven shape imparting steps, a molten elastic resin (not shown) is spun from a plurality of nozzles 301 provided on the lower end surface of the spinning head 300, and a plurality of elastic filaments 30 in a molten or softened state are extruded. Spin in this way. The spinning nozzles 301 are arranged in a row in the spinning head 300 along the width direction orthogonal to the conveying direction of the first and second sheet materials 10 and 20. The distance between the adjacent spinning nozzles 301 is appropriately determined. The diameter of the spinning nozzle 301 is preferably 0.1 mm or more, more preferably 0.2 mm or more. The diameter is preferably 2 mm or less, more preferably 0.6 mm or less.
The "elasticity" of the elastic filament 30 means that the elastic filament 30 has elasticity when it is taken out from the elastic sheet 50. Elasticity means that it can be stretched and returns to a length of 1.1 times or less of the original length when the force is released from the state of being stretched 1.3 times the original length. Say. The elastic filament 30 preferably has a diameter of 1 mm or less, more preferably 0.3 mm or less, and even more preferably 0.2 mm or less.

Then, before the plurality of elastic filaments 30 are solidified, a bonding step is performed in which the plurality of elastic filaments 30 are taken up and stretched while being fused and bonded to the first sheet material 10. At that time, the plurality of elastic filaments 30 are pressed against the first sheet material 10 by the respective tensions of the plurality of elastic filaments 30 and fused without utilizing the nip force due to the mechanical pressure using the nip roll. At the same time, the plurality of elastic filaments 30 are pressed against the second sheet material 20 by the second sheet material 20 facing each other with the plurality of elastic filaments 30 sandwiched therein, and are fused and adhered. Hereinafter, a detailed description will be given.

The molten or softened filament-like elastic filament 30 spun from the spinning nozzle 301 merges with the first sheet 10 material and the second sheet material 20 unwound from the raw fabric at the same speed, and the first sheet material 20 is merged with the first sheet material 20 and the second sheet material 20. It is sandwiched between the sheet material 10 and the second sheet material 20 and picked up. The take-up speed of the elastic filament 30 is made to match the feeding speed of the first sheet material 10 and the second sheet material 20. The take-up speed of the elastic filament 30 affects the diameter and draw ratio of the elastic filament 30. That is, the elastic filament 30 is stretched by the tension due to the take-up until it merges with the first sheet material 10 and the second sheet material 20 after being spun, the molecules are oriented in the stretching direction, and the diameter becomes smaller. .. Further, the tension generated in the elastic filament 30 prevents the elastic filament 30 from being disturbed due to wind or static electricity. As a result, the filament-shaped elastic filaments 30 can be arranged in one direction without intersecting each other and bonded to the first sheet material 10 and the second sheet material 20.
The stretching of the elastic filament 30 referred to here is for forming a filament, until the elastic filament 30 extruded in the molten state is bonded to the first sheet material 10 and the second sheet material 20. During that time, it is supplied between the sheet materials while maintaining a molten or softened state. Therefore, not only stretching in a molten state (molten stretching) but also stretching in a softened state (softening stretching) may be used. The molten state is a state in which the resin flows when an external force is applied.

The elastic filament 30 is in a fusing state before solidification at the time of merging with the first sheet material 10 and the second sheet material 20. Therefore, the elastic filament 30 is fused to the 10 surfaces of the first sheet material and the 20 surfaces of the second sheet material, respectively, by its own fusion force. The temperature of the elastic filament 30 is preferably equal to or higher than the melting point of the resin material to be used from the viewpoint of ensuring fusion with the 10 surfaces of the first sheet material and the 20 surfaces of the second sheet material in this fusion. The temperature is preferably 100 ° C. or higher, and more preferably 120 ° C. or higher.

When the elastic filament 30 is fused, heat is not applied to the 10 surfaces of the first sheet material and the second sheet material 20 from the outside. Therefore, the elastic filament 30, the 10th surface of the first sheet material, and the second sheet material 20 are fused only by the heat of fusion of the elastic filament 30 that can be fused.

When the uneven rolls 102 and 202 are used in the bonding step, as shown in FIG. 2, the pitches P1 and P2 of the tooth grooves of the concave and convex rolls 102 and 202 are preferably equal or an integral multiple of positive. Additionally, than roll circumferential width W1 of the large径凸portion 104 of one of the concave convex roll 102, the roll peripheral direction of the distance D2 of the small-diameter recess 206 of the other roll 202 facing is widely. In other words, the width W2 of the large-diameter convex portion 204 of the opposite roll 202 in the roll circumferential direction is narrower than the distance D1 of the small-diameter concave portion 106 of one roll 102 in the roll circumferential direction. In short, W1 <D2, W2 <D1, and W1 and W2, D1 and D2 are different from each other.
As described above, the pitches P1 and P2 are equal or integral multiples of positive, W1 <D2, and W2 <D1, so that the large-diameter convex portions 104 and 204 of the concave-convex rolls 102 and 202 come into contact with each other. Never. As a result, the concave-convex roll 102 and the concave-convex roll 202 can rotate with a clearance from each other. Further, the clearance between the concave-convex roll 102 and the concave-convex roll 202 is adjusted to bring the nip pressure close to 0 while giving a conveying force to the laminated body of the first and second sheet materials 10 and 20 and the elastic filament 30. be able to. Further, the first and second sheet materials 10 and 20 have a concavo-convex shape along the peripheral surfaces of the tooth grooves of the concavo-convex rolls 102 and 202. Therefore, it is possible to prevent the first and second sheet materials 10 and 20 from being in close contact with each other, and to accurately fuse the first and second sheet materials 10 and 20 with the elastic filament 30.

Since the concave-convex rolls 102 and 202 having the above-mentioned tooth grooves are used, the first sheet material 10 is in contact with the teeth (large-diameter convex portion 104) of the concave-convex roll 102. Further, the second sheet material 20 is in contact with the teeth (large-diameter convex portion 204) of the concave-convex roll 202. In such a state, a plurality of elastic filaments 30 in a molten or softened state are supplied between the concave-convex rolls 102 and 202. That is, a plurality of elastic filaments 30 in a molten or softened state are supplied between the first sheet material 10 and the second sheet material 20.
The plurality of elastic filaments 30 supplied between the concave-convex rolls 102 and 202 first come into contact with the tip of the large-diameter convex portion of one of the concave-convex rolls. For example, it is assumed that the tip portion 104A of the large-diameter convex portion 104 of the concave-convex roll 102 is first contacted. Then, since the concave-convex rolls 102 and 202 are rotating, the elastic filament 30 then comes into contact with the tip portion 204A of the large-diameter convex portion 204 of the concave-convex roll 202. In this way, due to the rotation of the concave-convex rolls 102 and 202, the elastic filaments 30 alternate in the order of the tip 104A of the large-diameter convex portion 104 of the concave-convex roll 102 and the tip 204A of the large-diameter convex portion 204 of the concave-convex roll 202. Will come into contact with. The elastic filament 30 first comes into contact with the tip portion 104A of the large-diameter convex portion 104 or the tip portion 204A of the large-diameter convex portion 204, depending on the supply direction of the elastic filament 30.

Then, since the large-diameter convex portion 104 enters the small-diameter concave portion 206 and the large-diameter convex portion 204 enters the small-diameter concave portion 106, the plurality of elastic filaments 30 are supported by the large-diameter convex portion 104 via the first sheet material 10. , Supported by the large diameter convex portion 204 via the second sheet material 20. Therefore, due to the tension generated in the elastic filament 30 between the large-diameter convex portions 104 and 204, the elastic filament 30 is alternately fused and adhered to the first sheet material 10 and the second sheet material 20. As a result, the non-fused regions 11 and 21 of the elastic filament 30 are formed on both the first sheet material 10 and the second sheet material 20, and these regions serve as ventilation passages to improve the air permeability of the elastic sheet 50. Let me.

At that time, the elastic filament 30 is pressed against the first sheet material 10 side and the second sheet material 20 side by the tension of the elastic filament 30, so that the elastic filament 30 is softly adhered. To be softly bonded means that the elastic filament is bonded to a state in which the cross section of the elastic filament is hardly deformed by the bonding process. For example, when tension is applied to the elastic filament using a nip roll, the entire elastic filament is adhered in a stretched state, so that the cross section of the elastic filament is greatly deformed and adhered to the sheet material. .. On the other hand, in the present manufacturing method, since the elastic filament 30 is only adhered at the tops of the large-diameter convex portions 104 and 204, the cross-sectional shape of the elastic filament 30 is less likely to be deformed. Moreover, by cooling the concave-convex rolls 102 and 202, the elastic filament 30 in the molten or softened state is cooled while maintaining the elastic state. By this cooling, the elastic filament 30 arranged between the large-diameter convex portion 104 and the large-diameter convex portion 204 is in a free state without adhering to the first sheet material 10 and the second sheet material 20. Therefore, the deformation of the cross-sectional shape of the entire elastic filament 30 is less likely to occur.
Therefore, since the fibers of the non-woven fabric do not bite into the elastic filaments 30 by the bonding step, the elastic forces of the plurality of elastic filaments 30 are not hindered. Therefore, a highly stretchable and flexible elastic sheet 50 can be obtained. In addition, the uneven first sheet material 10 and the second sheet material 20 form fine folds on the elastic sheet 50, which makes the elastic sheet 50 soft to the touch, good in appearance, and thin.

The tension of each of the plurality of elastic filaments 30 can be adjusted by the meshing depth G of the large-diameter convex portion 104 and the large-diameter convex portion 204. To reduce the tension of the elastic filament 30, the meshing depth G is made shallow, and to increase the tension, the meshing depth G is made deep. The tension of the elastic filament 30 is determined by appropriately selecting the meshing depth G depending on the material, thickness, etc. of the elastic filament 30.

It is preferable to perform stretching processing on the elastic sheet 50 formed by adhering the elastic filament 30 manufactured by the above manufacturing method in order to further increase the elongation.
As shown in FIG. 3, the stretching process is performed by the stretching device 400. The stretching device 400 applies a stretching process to the stretchable sheet 50 conveyed in the machine flow direction (MD) by engaging a pair of tooth groove rolls 401 and 402. This stretching process is also referred to as a tooth groove stretching process. As the tooth groove stretching process, a method similar to the method described in Patent Document 1 can be used.

The tooth groove rolls 401 and 402 have a plurality of teeth 401A and 402A having lengths in the rotation axis direction arranged on the peripheral surface at equal intervals in the roll circumferential direction. The tooth groove rolls 401 and 402 have grooves between the teeth 401A and 401A and between the teeth 402A and the teeth 402A, and are arranged so that the teeth mesh with each other. That is, the tooth groove roll 401 is loosely inserted between the teeth 401A of the tooth groove roll 401 and the tooth 402A of the tooth groove roll 402 is loosely inserted between the teeth 401A of the tooth groove roll 401. And the tooth groove roll 402 are combined.

Further, a pair of in-feed rolls 403 and 404 are arranged on the upstream side of the tooth groove rolls 401 and 402. By adjusting the rotation speed V3 of the in-feed rolls 403 and 404, the supply speed of the elastic sheet 50 between the tooth groove rolls 401 and 402 can be adjusted. Further, a pair of outfeed rolls 405 and 406 are arranged on the downstream side of the tooth groove rolls 401 and 402. By adjusting the rotation speed V4 of the outfeed rolls 405 and 406, it is possible to adjust the feeding speed of the stretched elastic sheet 52 from between the tooth groove rolls 401 and 402.

Specifically, the tooth groove stretching process is performed as follows.
As shown in FIG. 4, when the tooth groove roll 401 is rotated in the direction of arrow F1 and the tooth groove roll 402 is rotated in the direction of arrow F2, the teeth 401A and 402A are sequentially meshed with the opposing grooves in the circumferential direction. At this time, the elastic sheet 50 is partially stretched by pushing the elastic sheet 50 in the opposite directions (directions of the grooves facing each other) between the teeth 401A and the tips of the teeth 402A. In particular, the force that the region (411-412) and the region (413-414) deeply penetrates into the groove in which the teeth 401A and 402A face each other and extends becomes stronger. In the region (411-412), the meshing depth at which the teeth 401A and the teeth 402A enter each other's grooves gradually increases, and the pushing force against the elastic sheet 50 gradually increases. In the region (413-414), the teeth 401A and 402A are gradually separated from the opposite grooves, and a force for pulling the elastic sheet 50 is generated. As a result, the elongated strip-shaped elastic sheet 50 inserted between the tooth groove rolls 401 and 402 is stretched along the extending direction of the elastic filament 30 (see FIG. 1).

By the tooth groove stretching process, the elastic filament 30 exhibits its extensibility and stretches in the stretched portion of the elastic sheet 50. The first and second sheet materials 10 and 20 on the front and back surfaces are appropriately broken before and after being fused to the elastic filament 30 in an attempt to follow this. This increases the voids and improves the air permeability of the elastic sheet 52. By improving the air permeability, the transpiration of steam is also improved. In addition, the folds become finer, resulting in a thin elastic sheet that looks good.

As described above, according to the manufacturing method of the present embodiment, it is possible to economically manufacture a stretchable sheet having higher elongation and excellent stretchability and flexibility.

In the present embodiment, the tooth groove extension ratio is a value obtained by the following formula (1). V1, V2, L, G, V3 and V5 are as follows.
L: Average gap (mm) between the tooth 401A of the tooth groove roll 401 and the tooth 402A of the tooth groove roll 402.
G: Engagement depth (mm)
V1: Conveyance speed of elastic sheet 50 V2: Peripheral speed of uneven rolls 401 and 402 V3: Peripheral speed of infeet nip rolls 403 and 404 (m / min)
V5: Peripheral speed V5 (m / min) of tooth groove rolls 401 and 402
The peripheral speed V5 of the tooth groove rolls 401 and 402 is a peripheral speed whose radius is a point obtained by halving the amount of engagement between the tooth 401A of the tooth groove roll 401 and the tooth 402A of the tooth groove roll 402. The average gap L is an average value of the gap L1 in the region (411-421) and the gap L2 in the region (413-414).

Next, the members used in the manufacturing method of the present invention will be described.

As the first sheet material 10 and the second sheet material 20, various materials can be used without particular limitation. For example, a spunbonded non-woven fabric, an air-through non-woven fabric, an air-laid non-woven fabric, a spunlaced non-woven fabric, a needle punched non-woven fabric, a laminated non-woven fabric of a spunbond layer and a melt blown layer, and an SMS non-woven fabric can be used. A spunbonded non-woven fabric is preferable from the viewpoint of being inexpensive, having excellent processing suitability, and being thin, which contributes to slimming of absorbent articles. In the case of the above-mentioned laminated non-woven fabric, it is preferable that the spunbond layer is arranged on either the front surface or the back surface of the melt blown layer or both surfaces.

The first sheet material 10 and the second sheet material 20 are inexpensive and have a good feel to the touch, and from the viewpoint of processing suitability, the basis weight ^{is preferably 10 g / m 2} or more, and 100 g / m. preferably ² or less, and more preferably 25 g / ^{m 2} or less.

When a spunbonded non-woven fabric is used, the constituent fibers constituting the spunbonded non-woven fabric are made of a thermoplastic resin, and the thermoplastic resin includes a polyolefin resin, a polyester resin, a polyamide resin, an acrylonitrile resin, a vinyl resin, and vinylidene. Examples include based resins. Examples of the polyolefin resin include polyethylene, polypropylene, polybuden and the like. Examples of the polyester resin include polyethylene terephthalate and polybutylene terephthalate. Examples of the polyamide resin include nylon and the like. Examples of the vinyl resin include polyvinyl chloride and the like. Examples of the vinylidene resin include polyvinylidene chloride and the like. Modified products and mixtures of these various resins can also be used.

The first sheet material 10 and the second sheet material 20 may be non-extensible or extensible. From the viewpoint of enhancing the extensibility of the obtained stretchable sheet 10, the first sheet material 10 and the second sheet material 20 are preferably those having extensibility.
As an example of the stretchable sheet material, it is preferable to use an inelastic fiber made from a high elongation fiber having a constant fiber diameter as a raw material in that a stretchable sheet having a high maximum elongation can be obtained. The high elongation means, for example, a fiber having a maximum elongation of 80% or more, particularly 120% or more, and 800% or less, particularly 650% or less. The elongation of the fiber conforms to JIS L-1015, and the temperature of the measurement environment is 20 ± 2 ° C., the humidity is 65 ± 5% RH, the gripping interval of the tensile tester is 20 mm, and the tensile speed is 20 mm / min. Based on measurement. The high-elongation fiber is preferably a low-stretch non-elastic fiber. The low-stretched inelastic fibers described above include both fibers that have been stretched at a low draw ratio after spinning and fibers that have not been stretched, that is, unstretched fibers.

As the elastic filament 30, those having elasticity and capable of fusion with the first sheet material 10 and the second sheet material 20 can be used without particular limitation. For example, a thermoplastic elastomer can be used. Examples of the thermoplastic elastomer include styrene-based elastomers such as styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-ethylene-butadiene-styrene (SEBS), and styrene-ethylene-propylene-styrene (SEPS). , Styrene-based elastomers (ethylene-based α-olefin elastomers, propylene-based elastomers obtained by copolymerizing ethylene, butene, octene, etc.), polyester-based elastomers, polyurethane-based elastomers, and the like.
The elastic filament 30 may be a single component type, or may be a core sheath type or a side-by-side type multi-component type. The spinnability of the elastic filament 30 is enhanced, the fusion strength between the elastic member filament 30 and the first sheet material 10 and the second sheet material 20 is enhanced, and various characteristics of the elastic sheet 50 finally obtained (for example, expansion and contraction). From the viewpoint of improving the property), a multi-component system is preferable. For example, in order to increase the elasticity of the elastic sheet 10, it is preferable to combine a polypropylene-based elastomer resin and a styrene-based elastomer resin.
Regardless of whether the elastic filament 30 is a single component system or a multi-component system, the thickness of the elastic filament 30 in the manufactured elastic sheet 50 is from the viewpoint of improving flexibility, appearance, and productivity. Therefore, the diameter is preferably 10 μm or more and 300 μm or less, and more preferably 20 μm or more and 150 μm or less. The pitch between the elastic filaments 30 is preferably 0.1 mm or more and 10 mm or less, and more preferably 0.5 mm or more and 2 mm or less.

As the release agent to be applied to the surfaces of the first sheet material 10 and the second sheet material 20, those usually used in this type of article such as silicone resin type, fluorine resin type, or octadecyl isocyanate type may be adopted. it can.

The elastic sheet according to the present invention can be used for various applications requiring elasticity. For example, it can be used as a constituent member of absorbent articles such as the above-mentioned disposable diapers, sanitary napkins, panty liners, incontinence pads, and urine absorbing pads.

Hereinafter, the present invention will be described in more detail based on Examples. The present invention is not construed as being limited by these examples. In this example, "parts" and "%" indicating the composition are both based on mass unless otherwise specified.

(Example 1)
The method for producing an elastic sheet using the apparatus shown in FIGS. 1 and 2 was carried out under the following conditions. The stretchable sheet sample S1 of Example 1 was prepared using the stretchable sheet thus obtained.
As the first sheet material 10 and the second sheet material 20, spunbonded non-woven fabric having ^{a basis weight of 20 g / m 2 was used.} The fibers of the first sheet material 10 were inelastic fibers. As the elastic resin constituting the elastic filament 30, SEPS, a styrene-based elastomer resin, was used. The elastic filament 30 had a diameter of 0.1 mm as a fiber (filament) after being spun, stretched and cooled. Using an apparatus having the same configuration as the manufacturing apparatus (spinning apparatus) shown in FIGS. 1 and 2, a composite sheet in which a plurality of elastic filaments were arranged at equal pitches was produced. Further, as shown in FIG. 3, the above-mentioned manufacturing is performed on an elastic expression processing apparatus (stretching apparatus) provided with a pair of tooth groove rolls 401A and 402A in which teeth and tooth bottoms are alternately arranged in the roll circumferential direction (actual length direction). By passing the composite sheet through the composite sheet, elasticity was imparted to the composite sheet, and the desired elastic sheet was manufactured.

(1) The uneven shape imparting step was performed.
The uneven rolls 101 and 102 had the same tooth groove pitch and were set to 2 mm. The meshing depth between the large-diameter convex portions 103 and 104 was set to 3 mm.
Further, the uneven rolls 201 and 202 had the same tooth groove pitch and were set to 2 mm. The meshing depth between the large-diameter convex portions 203 and 204 was set to 3 mm.
The peripheral speeds of the uneven rolls 101, 102, 201, and 202 were set to 20 m / s, and the transport speeds of the first sheet material 10 and the second sheet material 20 were set to 20 m / s.
Further, the tooth groove extension ratio was set to 3 times.
The uneven rolls 102 and 202 were cooled to 20 ° C. in order to perform the next bonding step.
(2) An adhesion process was performed.
The conditions of the uneven rolls 101, 102, 201, and 202 are the same as those in the uneven shape imparting step.

(Example 2)
The stretchable sheet 50 produced in Example 1 was further subjected to a tooth groove stretching process by the stretching device 400 shown in FIGS. 3 and 4. A stretchable sheet sample S2 was prepared in the same manner as in Example 1 except for the above. The mechanical stretching ratio is doubled, the meshing depth G between the teeth 401A and the teeth 402A is 2.5 mm, the pitch P3 between the teeth 401A of the tooth groove roll 401 and the pitch P4 between the teeth 402A of the tooth groove roll 402 are 2 mm. did.

(Comparative Example 1)
The stretchable sheet sample C1 of the comparative example of the stretchable sheet was prepared by the manufacturing method described in Patent Document 1 for the stretchable sheet described in Patent Document 1.

(Comparative Example 2)
The stretchable sheet sample C2 of the comparative example of the stretchable sheet was prepared by the manufacturing method described in Patent Document 1 for the stretchable sheet described in Patent Document 1.

The following tests were performed on each of the samples prepared in Examples 1 and 2 and Comparative Examples 1 and 2.

(1) Touch sensory evaluation method and evaluation criteria [touch (flexibility) on the non-elastic fiber layer side]
The feel of the elastic sheet on the non-elastic fiber layer side was evaluated. The touch was evaluated in the natural state (relaxed state). Five general adult male and female evaluators performed a five-point evaluation from 1 to 5, and the average score was rounded off. The evaluation criteria are 5 points for soft and non-sticky ones, 4 points for slightly preferable ones, 3 points for ordinary ones, 2 points for slightly unfavorable ones, and hard ones and sticky ones are preferable. The one that did not exist was given as one point. As the standard for the evaluation of the touch on the non-elastic fiber layer side, the sheet of Comparative Example 1 was regarded as an ordinary one (3 points), and the above evaluation was performed based on the sheet.

(2) Visual sensory evaluation method and evaluation criteria [Appearance]
The evaluation was carried out visually by the evaluator in a natural state (relaxed state) with the inelastic fiber layer side of the elastic sheet as the upper surface. Five general adult male and female evaluators performed a five-point evaluation from 1 to 5, and the average score was rounded off. The evaluation criteria are 5 points for those with a fine wave shape and inconspicuous holes, 4 points for slightly preferable ones, 3 points for ordinary ones, 2 points for slightly unfavorable ones, and many holes, which are conspicuous. One point was given as an unfavorable one. As the criteria for the appearance evaluation, the sheet of Comparative Example 1 was regarded as an ordinary one (3 points), and the above evaluation was performed based on the sheet.

The evaluation results of (1) and (2) above are as shown in Table 1 below.

As shown in Table 1, it was found that the elastic sheet of the present invention had a good touch (flexibility) and appearance.

10 1st sheet material 11, 21 Non-contact area 20 2nd sheet material 30 Elastic filament 50, 52 Elastic sheet 100 1st uneven structure shaping part 101, 102 Concavo-convex roll 103, 104 Large diameter convex part 104A Large diameter convex part Tip of 104 105, 106 Small diameter recess 200 Second uneven structure shaping part 201, 202 Concavo-convex roll 203, 204 Large diameter convex 204A Large diameter convex 204 tip 205, 206 Small diameter concave 300 Spinning head 301 Nozzle 400 Stretch Equipment 401, 402 Tooth groove rolls 401A, 402A Teeth 403, 404 having length in the direction of rotation axis
405, 406 Outfeed rolls 411-421, 413-414 Regions P1, P2, P3, P4 Tooth groove pitch D1 Small diameter recess 106 roll circumferential spacing D2 Small diameter recess 206 roll circumferential spacing G Engagement depth W1 Roll circumferential width of large-diameter convex portion 104 W2 Roll circumferential width of large-diameter convex portion 204 V3 Rotation speed of in-feed roll

Claims (5)

A method for producing an elastic sheet, wherein a plurality of elastic filaments are adhered to a pair of sheet materials made of non-woven fabric, and the plurality of elastic filaments are arranged so as to extend in one direction without intersecting each other.
An uneven shape imparting step of imparting an uneven shape to each of the pair of sheet materials,
It has an bonding step of fusing and adhering a plurality of elastic filaments in a molten or softened state to the sheet material.
The uneven shape imparting step and the bonding step are performed in order,
In the bonding step, elastic filaments are conveyed and merged between the pair of concavo-convex rolls having the concavo-convex shape imparted between the pair of concavo-convex rolls arranged so that the tooth grooves can mesh with each other. With the rotation of the roll , tension is applied to each of the plurality of elastic filaments, and the plurality of elastic filaments and the pair of sheet materials are formed at the top of the large-diameter convex portion of each of the pair of concave-convex rolls. adhered to,
The pitch of the tooth grooves of the pair of concave-convex rolls is the same or an integral multiple of positive, and the distance in the roll circumferential direction of the small-diameter concave portion of the other roll facing the width of the large-diameter convex portion of one concave-convex roll in the roll circumferential direction. A method for manufacturing an elastic sheet, which is wide and the pair of concave-convex rolls can rotate with a clearance from each other. The method for manufacturing an elastic sheet according to claim 1, wherein the uneven shape imparting step is to impart an uneven shape to the sheet material by passing the sheet material between the meshed uneven rolls used in the step. The method for manufacturing an elastic sheet according to claim 2, wherein the uneven shape imparting step is suction to each of the uneven roll sides used in the step. The method for manufacturing an elastic sheet according to claim 2 or 3, wherein the uneven shape imparting step is a method for cooling the uneven roll used in the step. The method for producing an elastic sheet according to any one of claims 1 to 4 , wherein the elastic sheet is stretched after the bonding step.

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