JP3739286B2 - Elastic stretch composite sheet and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an elastic stretchable composite sheet formed of an elastic stretchable fiber layer and an inelastically stretchable fiber layer and a method for producing the same.
[0002]
[Prior art]
JP-A-9-512313 discloses a composite nonwoven fabric composed of at least two layers. This composite nonwoven fabric includes a first layer made of a stretchable nonwoven fabric formed of multipolymer fibers and a stretchable second layer. The first layer is an inelastically stretchable layer, and for example, a spunbond nonwoven fabric, a meltblown nonwoven fabric, or the like made of continuous filaments that can be stretched inelastically is used. The second layer is an elastically stretchable layer, and for example, an elastic cloth is used. These first layer and second layer are processed and laminated by a thermal method or a chemical method using an adhesive or the like. This composite nonwoven fabric can be stretched to permanently deform the first layer and then shrink by the elastic force of the second layer. What is obtained in this way is also used as an elastic stretch composite nonwoven fabric.
[0003]
[Problems to be solved by the invention]
When the known composite nonwoven fabric uses continuous fibers as multipolymer fibers, and the first layer and the second layer are bonded at a site treated by a thermal method, the composite nonwoven fabric is When stretched excessively in one direction, the multi-polymer fibers forming the first layer break near the bonding site or between the bonding site and the bonding site, and the composite nonwoven fabric becomes fuzzy, It sometimes loses the gloss and smooth feel that are characteristic of continuous fibers. In addition, the multipolymer fiber may be peeled off from the bonding site before breaking. Even if the cross-section of the multipolymer fiber is circular, the bonding site is usually pressed under heating and partially deformed flat, and the deformed portion is the bonding site. When it is peeled off and mixed in the multipolymer fiber, the part gives a unique irritation to the skin, and the composite non-woven fabric becomes unsatisfactory.
[0004]
The subject of this invention is a composite sheet comprising a first fiber layer elastically stretchable and a second fiber layer inelastically extendable as seen in the above-mentioned known examples. The purpose of the present invention is to improve the stretchable continuous fibers forming the second fiber layer so as not to cause deterioration of the touch even if the sheet is stretched excessively. In the present invention, excessively stretching the composite sheet means that the continuous fiber is stretched to the vicinity of the bonding site with the first fiber layer or just before breaking between the bonding site and the bonding site. is doing.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is directed to a first fiber assembly layer that is elastically stretchable in at least one of two directions orthogonal to each other and has upper and lower surfaces, and to the one direction. A second fiber aggregate layer that is inelastically extendable and overlaps with either the upper or lower surface of the first fiber aggregate layer and is intermittently bonded to the first fiber aggregate layer in at least one direction. An elastic stretchable composite sheet and a method for producing the same.
[0006]
In the elastic stretchable composite sheet, the present invention is characterized in that the first fiber aggregate layer is made of elastic stretchable first fibers that are elastically stretchable by 200% or more , and the second fiber aggregate layer is The second fiber is formed of continuous fibers that are inelastically extendable by 50% or more and spread on either the upper or lower surface of the first fiber assembly layer, and the second fibers are intermittent in the one direction. and said second fiber and said first fibers forming enters into the first fibers to each other in the gap by bonding and mechanically the only by confounding first fiber assembly layer and the second fibrous assembly layer In a part of the entanglement between the first fiber and the second fiber, when the composite sheet is stretched in the one direction at a required magnification or more, the second fiber is formed so as to be out of the entanglement before breaking. Being there.
[0007]
Moreover, in the method for producing the elastic stretchable composite sheet, the present invention is characterized as follows. More than 50% of the first fiber aggregate layer should be elastically stretched on the first fiber web formed of elastic stretchable first fibers capable of being stretched by 200% or more. A second fiber web formed of second fibers, which are possible continuous fibers, is overlapped on a support belt and continuously traveled in the one direction together with the support belt, and above the second fiber web during the travel In this case, high-pressure water is jetted from a large number of fine nozzles arranged in a row in the width direction of the second fiber web toward the second fiber web, and the second fiber is intermittently moved in the one direction by the high-pressure water. The first fiber and the second fiber are mechanically entangled by entering the gap between the first fibers, and in a part of the entanglement of the first fiber and the second fiber, the composite sheet is Extend beyond the required magnification in the direction Once, the second fibers into and out from the entangled before the break, is bound only by the entanglement and the second fiber aggregate layer and the first fiber assembly layer.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The details of the elastic stretchable composite sheet and the method for producing the same according to the present invention will be described with reference to the accompanying drawings.
[0009]
A composite sheet 1 shown in a partially broken perspective view in FIG. 1 is composed of two upper and lower layers, and is an aggregate of elastically stretchable fibers 6 that forms a lower layer and a non-stretching layer 2. And a stretched layer 3 which is an aggregate of continuous fibers 11 which can be stretched elastically and forms an upper layer. The stretchable layer 2 can elastically stretch 200% or more, more preferably 400% or more, and even more preferably 600% or more in at least one direction A of the two directions A and B orthogonal to each other. Preferred examples of the fibers 6 of the stretchable layer 2 include short fibers and long fibers having a fiber diameter of 0.1 to 50 μm and formed of an elastic polymer material such as a styrene elastomer or urethane and having a fiber length of about 20 to 100 mm. There are fibers, and aggregates of these fibers include elastic stretch fiber aggregates such as spunbond nonwoven fabrics and meltblown nonwoven fabrics having a basis weight of 15 to 200 g / m ² . The stretchable layer 2 has an upper surface 7 and a lower surface 8, and the stretched layer 3 is located on the upper surface 7.
[0010]
The stretchable layer 3 is an aggregate of continuous fibers 11 that can be stretched inelastically, and is 50% or more in the direction A in which the stretchable layer 2 stretches, more preferably 100% or more, and even more preferably 150% or more inelastic. The amount when stretched appears as a permanent strain in the continuous fiber 11. The continuous fiber 11 has a fine diameter of 0.1 to 50 [mu] m and is made of a polymer material such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-butene copolymer, and polyester. And those composed of a mixture of two or more of these polymer materials, and those formed of composite fibers composed of these polymer materials. The aggregate of the continuous fibers 11 is preferably one having a basis weight of ² to 100 g / m ² , and the aggregate is obtained by, for example, the above-described various polymer materials by a direct spinning method such as a melt blown method or a spun bond method. It can be obtained by depositing a large number of continuous fibers 11 continuously extruded in an irregularly meandering state on an endless belt running in one direction. The meandering state means a state in which the continuous fiber 11 does not extend linearly in the one direction, but is in an arc, a ring, or a bend.
[0011]
The stretchable layer 2 and the stretchable layer 3 enter the gaps between the fibers 6 forming the stretchable layer 2 intermittently in the length direction of the composite sheet 1 by the individual continuous fibers 11 forming the stretchable layer 3. Thus, the composite fiber 1 is formed by bonding the continuous fibers 11 and the fibers 6 formed by doing so through mechanical entanglement. The continuous fiber 11 that has entered the gap between the fibers 6 may penetrate the stretchable layer 2.
[0012]
In order to entangle the continuous fiber 11 and the fiber 6, the stretchable fiber web made of the continuous fiber 11 is superimposed on the stretchable fiber web made of the fiber 6 and is continuously run in one direction. A method of injecting high-pressure water from a fine nozzle onto the web from above can be employed. The stacked both fiber webs are placed on a perforated or non-porous endless belt and run at, for example, 15 to 150 m / min. The nozzles preferably have a pore diameter of 50 to 150 μm, are arranged in one or more rows at a pitch of 0.3 to 2 mm over the entire width of the extensible fiber web, and the water pressure is preferably in the range of 7 to 15 MPa. Such high-pressure water can be repeatedly injected once or twice or more to the extensible fiber web. The continuous fiber 11 is entangled mechanically with the fiber 6 in an intermittent state in the traveling direction of the extensible fiber web, where the portion injected with high-pressure water enters the stretchable fiber web. The fibers 6 of the elastic fiber web can be elastically stretched when high-pressure water is jetted to widen the gaps between the fibers 6 and facilitate the entry of the continuous fibers 11 into the gaps. After injection of high-pressure water, it contracts to narrow the gap, making it difficult for the continuous fibers 11 that have entered to retreat. Thus, the bond between the stretchable layer 2 and the stretchable layer 3 is strengthened. The continuous fiber 11 extends while irregularly meandering in the running direction of the extensible fiber web, and the entangled portion generated by the action of high-pressure water from the nozzles arranged in a line in the width direction of the extensible fiber web is the continuous fiber 11. It appears intermittently in the length direction.
[0013]
Since the elongated layer 3 of the composite sheet 1 of FIG. 1 formed in this way is formed of continuous fibers 11 and does not have a fiber end portion in a substantial sense, it has a lint-free and glossy appearance, and is smooth Have a soft touch. When the composite sheet 1 is stretched by a required magnification in the direction A in FIG. 1, if the magnification is within the range of elastic deformation of the stretchable layer 2 and is equal to or less than the breaking elongation of the continuous fiber 11, continuous. After the fiber 11 is stretched inelastically and elastically contracted by the action of the stretchable layer 2, the stretch amount at that time becomes permanent and appears in the continuous fiber 11, and the continuous fiber 11 is entangled with the entangled portion. A larger arc or ring is drawn between the region and the region before the region is stretched, and the stretched layer 3 is increased in volume so that the flexibility when touching the skin is further improved. The composite sheet 1 changed to such a state can also be used as an elastic stretchable composite sheet.
[0014]
FIG. 2 is a partially enlarged perspective view of the composite sheet 1. In this figure, a single continuous fiber 11 is entangled with the fiber 6 at sites p, q, and r. The composite sheet 1 is stretched in the direction A by the required magnification, the continuous fiber 11 is in tension between these parts p, q, r, and the total length of the fiber 11 extending between the parts p, q, r is the part p. Longer than the straight line distance indicated by the phantom line between r and r. When the composite sheet 1 at this time is further extended in the direction A and the continuous fiber 11 seems to be out of the confounding with the fiber 6 at the site q, the continuous fiber 11 sag between p and r, The composite sheet 1 easily extends in the direction A without breaking the continuous fiber 11. Therefore, in the preferable composite sheet 1, when the continuous fiber 11 is in a tension state between the portions where the continuous fibers 11 are mechanically entangled, particularly when the tension state is near the breaking elongation of the continuous fiber 11. In addition, the continuous fiber 11 is formed so as to be out of mechanical entanglement with the fiber 6 in some of the entangled portions so that the composite sheet 1 can be further extended without breaking the continuous fiber 11. In this way, in the composite sheet 1 in which the continuous fibers 11 are out of entanglement with the fibers 6, the stretched layer 3 does not fluff even if it is excessively stretched, and the glossy appearance and smooth texture unique to the continuous fibers 11. And can be maintained. The strength of the entanglement between the continuous fiber 11 and the fiber 6 can be adjusted by the injection conditions of the high-pressure water on the continuous fiber 11.
[0015]
FIG. 3 is a drawing similar to FIG. 1 showing an example of an embodiment of the present invention. This composite sheet 1 has a three-layer structure composed of two upper and lower layers and an intermediate layer, and the elastic layer is elastically stretchable so that the intermediate layer can elastically expand and contract in at least one of the two directions A and B orthogonal to each other. The stretchable layer 2 is made of fibers, and the upper and lower layers are stretched layers 3 made of continuous fibers 11 that can stretch inelastically in at least the direction A of the two directions A and B. The stretchable layer 2 is formed in the same manner as the stretchable layer 2 in FIG. 1, and for this, for example, a melt blown nonwoven fabric having a basis weight of 30 g / m ² made of styrene elastomer fibers having a fine diameter of 15 μm is used. Each of the stretched layers 3 is also formed in the same manner as the stretched layer 3 in FIG. 1, and for this, for example, a fiber assembly made of continuous fibers of polypropylene and having a basis weight of 15 g / m ² is used. However, in the stretchable layer 3 forming the upper layer and the stretchable layer 3 forming the lower layer in FIG. 3, different basis weights or types of continuous fibers 11 can be used. In order to obtain this composite sheet 1, high-pressure water is sprayed on each of the stretched layers 3 stacked on the upper and lower surfaces of the stretchable layer 2, and if necessary, spraying on each stretched layer 3 is repeated twice or more. The layers may be combined and integrated.
[0016]
The elastic elastic sheet according to the present invention and the second elastic elastic composite sheet obtained by elastically expanding and contracting the composite sheet have both elasticity, good touch and good external feeling. Therefore, it is suitable as a sheet material for disposable diapers, sanitary napkins, disposable medical gowns and the like.
[0017]
【The invention's effect】
The elastic stretchable composite sheet according to the present invention includes a stretchable fiber web made of continuous fibers that can be stretched inelastically on at least one side of an elastically stretchable fiber web. It has a glossy appearance and a touch that is characteristic of continuous fibers. Even if this composite sheet is stretched excessively, the continuous fibers come out of the entanglement before breakage, so that the fluffing does not increase or the touch does not worsen.
[Brief description of the drawings]
FIG. 1 is a partially broken perspective view of a composite sheet.
FIG. 2 is a view showing a state when a continuous fiber and a stretchable fiber layer are stretched.
FIG. 3 is a drawing similar to FIG. 1 showing an example of an embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Composite sheet 2 1st fiber aggregate layer 3 2nd fiber aggregate layer 6 1st fiber 11 2nd fiber, continuous fiber

Claims (4)

A first fiber aggregate layer elastically stretchable in at least one of two directions orthogonal to each other and having upper and lower surfaces; and inelastically extendable in the one direction and above the first fiber aggregate layer In the elastic stretchable composite sheet formed by the second fiber aggregate layer that overlaps with any of the lower surfaces and is intermittently bonded to the first fiber aggregate layer in at least one direction,
The first fiber assembly layer is made of elastic stretchable first fibers that can be elastically stretched by 200% or more, and the second fiber assembly layer is non-elastically stretchable by 50% or more. The first fiber is formed of a second fiber formed of continuous fibers spreading on either the upper or lower surface of the layer, and the second fiber is formed by intermittently entering the gap between the first fibers in the one direction. The first fiber aggregate layer and the second fiber aggregate layer are bonded only by mechanically entangled with the second fiber, and in a part of the entanglement of the first fiber and the second fiber, The elastic stretchable composite sheet is characterized in that when the composite sheet is stretched in the one direction at a required magnification or more, the second fibers are detached from the entanglement before breaking.   2. The elastic stretchable composite sheet according to claim 1, wherein the second fiber aggregate layer overlaps with an upper surface and a lower surface of the first fiber aggregate layer to form a three-layer structure as a whole.   The elastic stretchable composite sheet according to claim 2, wherein the second fiber aggregate layer of the upper surface and the lower surface is different in basis weight and type of the second fibers forming them. A first fiber aggregate layer elastically stretchable in at least one of two directions orthogonal to each other and having upper and lower surfaces; and inelastically extendable in the one direction and above the first fiber aggregate layer In the method for producing an elastic stretchable composite sheet formed by a second fiber aggregate layer that overlaps with any of the lower surfaces and is intermittently bonded to the first fiber aggregate layer in at least one direction,
More than 50% of the first fiber aggregate layer should be elastically stretched on the first fiber web formed of elastic stretchable first fibers capable of being stretched by 200% or more. A second fiber web formed of second fibers, which are possible continuous fibers, is overlapped on a support belt and continuously traveled in the one direction together with the support belt, and above the second fiber web during the travel In this case, high-pressure water is jetted from a large number of fine nozzles arranged in a row in the width direction of the second fiber web toward the second fiber web, and the second fiber is intermittently moved in the one direction by the high-pressure water. The first fiber and the second fiber are mechanically entangled by entering the gap between the first fibers, and in a part of the entanglement of the first fiber and the second fiber, the composite sheet is Extend beyond the required magnification in the direction Then, the first fiber aggregate layer and the second fiber aggregate layer are bonded only by the interlace so that the second fiber is out of the interlace before breaking. .

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