Patent Application
20180177645
The present invention relates to a nonwoven fabric, and particularly a nonwoven fabric comprising a plurality of protrusions on the surface, and an absorbent article using it.
Absorbent articles such as disposable diapers and sanitary napkins are usually used in direct contact with the skin of the user, and some are even worn for long periods. Absorbent articles are therefore desired to have excellent cushioning properties and flexibility, and a satisfactory feel on the skin.
As for such an absorbent article, PTL 1 discloses a nonwoven fabric to be used as the top sheet of an absorbent article, the nonwoven fabric having first protrusions protruding on a first surface side and second protrusions protruding on a second surface side, which alternately spread out in two directions, a first direction and a second direction, within the plane, and connected through wall sections, wherein the wall sections form a ring structure, and the fiber density of the first protrusions is lower than the fiber density of the second protrusions. With this nonwoven fabric, the fluid drawing property is satisfactory, it has a soft cushioning property, good restoration after pressing and particularly excellent excreta-collecting properties.
However, because the nonwoven fabric disclosed in PTL 1 has relatively low fiber density at the wall sections, when the nonwoven fabric is used as a top sheet in an absorbent article, the protrusions have high collapsability under pressure such as body pressure of the wearer, and in some cases it has not been possible to adequately exhibit the satisfactory cushioning properties of the protrusions for long periods. In addition, since the nonwoven fabric disclosed in PTL 1 has relatively high fiber density at the top sections of the protrusions, and the top sections of the protrusions are rounded and in point-contact with the skin surface, the hardness of the protrusions tends to be felt and a satisfactory feel on the skin cannot be obtained in some cases.
It is therefore an object of the present invention to provide a nonwoven fabric that can adequately exhibit satisfactory cushioning properties for long periods, and that has a satisfactory feel on the skin.
The nonwoven fabric according to one aspect (aspect 1) of the present invention is a nonwoven fabric comprising a base having a mutually opposite first surface and second surface and extending out flat, and a plurality of protrusions protruding from the first surface of the base in the thickness direction, wherein each of the protrusions comprises a peripheral surface section standing up from the first surface of the base in a thickness direction and a top surface section having a top surface forming a crown of the each of the protrusions, the fiber density of the peripheral surface section is higher than the fiber density of the top surface section, and at least a part of a top surface perimeter portion of the top surface section is constructed as a thickest section which has the greatest thickness in the nonwoven fabric.
According to the nonwoven fabric of aspect 1, the construction is such that the fiber density of the peripheral surface section that stand up in the thickness direction of the protrusion is higher than the fiber density of the top surface section, and therefore even when pressure by body pressure or the like is applied in the thickness direction of the nonwoven fabric, since the peripheral surface section functions as columns supporting the top surface section, the protrusion is less likely to collapse, and even if the top surface section of the protrusion collapses, since at least a part of the top surface perimeter portion of the top surface section is constructed as the thickest section having the greatest thickness in the nonwoven fabric, it is possible to restore collapse (deformation) of the top surface section by the resiliency of the thickest section. This allows the nonwoven fabric of aspect 1 to adequately exhibit the satisfactory cushioning properties of the protrusions for long periods.
In addition, since the thickest section has satisfactory resiliency and flexibility, even if the protrusion has the peripheral surface section with high fiber density, the hardness of the protrusion is less likely to be felt and a satisfactory feel on the skin can be provided.
Furthermore, according to another aspect (aspect 2) of the present invention, in the nonwoven fabric of aspect 1, the construction is such that the fiber density of the peripheral surface section is higher than the fiber density of the base.
According to the nonwoven fabric of aspect 2, the construction is such that the fiber density of the peripheral surface section is higher than the fiber density of the base, and therefore pressure in the thickness direction that is applied from the first surface side of the protrusion by body pressure or the like can be buffered by bending of the base on the second surface side. Thus, the protrusions will be even less likely to collapse, and excellent flexibility can be imparted to the nonwoven fabric.
Furthermore, according to another aspect (aspect 3) of the present invention, in the nonwoven fabric of aspect 1 or 2, the top surface of the top surface section is depressed.
According to the nonwoven fabric of aspect 3, the top surface of the top surface section is depressed, and therefore even when pressure has been applied in the thickness direction from the first surface side of the protrusion by body pressure or the like, since the pressure is applied in a manner centered on the section of the top surface supported by the peripheral surface section (i.e., the top surface perimeter portion), it is less likely for the top surface to deform first and thus cause the protrusion as a whole to collapse.
Furthermore, according to another aspect (aspect 4) of the present invention, in the nonwoven fabric of any of aspects 1 to 3, a planar shape of the top surface of the top surface section is circular.
According to the nonwoven fabric of aspect 4, the planar shape of the top surface of the top surface section is circular, and the top surface is uniformly supported along the top surface perimeter portion by the peripheral surface section, and therefore high collapsable section is unlikely to form locally in the protrusion, and the protrusion is even less likely to collapse.
Furthermore, according to another aspect (aspect 5) of the present invention, in the nonwoven fabric according to any of aspects 1 to 4, the thickest section has the lowest fiber density in the nonwoven fabric.
According to the nonwoven fabric of aspect 5, the thickest section of the top surface section of the protrusion has the lowest fiber density in the nonwoven fabric, and therefore the resiliency and flexibility of the top surface perimeter portion is relatively high, and even when the top surface section of the protrusion collapses due to pressure such as body pressure, it is possible to more reliably restore collapse (deformation) of the top surface section. In addition, since the top surface perimeter portion has relatively high resiliency and flexibility, the hardness of the protrusions is even less likely to be felt, and satisfactory feel on the skin can be obtained.
Yet another aspect (aspect 6) of the present invention is an absorbent article including the nonwoven fabric according to any of aspects 1 to 5.
The absorbent article of aspect 6 includes a nonwoven fabric according to any of aspects 1 to 5, which can adequately exhibit satisfactory cushioning properties for long periods and has satisfactory feel on the skin, and therefore the wearer of the absorbent article can be provided with an excellent feel during wear for long periods.
According to the present invention it is possible to provide a nonwoven fabric that can adequately exhibit satisfactory cushioning properties for long periods, and that has a satisfactory feel on the skin.
Preferred embodiments of the nonwoven fabric of the present invention will now be explained in greater detail with reference to the accompanying drawings. Throughout the present description, unless otherwise specified, the concept of “an object placed on a horizontal surface in the deployed state being viewed in the thickness direction of the object from the top side in the vertical direction” will be referred to simply by the term “planar view”, and “the shape in the planar view” will be referred to simply as “the planar shape”.
Furthermore, throughout the present description, the widthwise direction DW is the widthwise direction (short direction) in the planar view, for a disposable diaper 1 (absorbent article) in the deployed state, the lengthwise direction DL is the lengthwise direction (front-back direction of the wearer) in the planar view for the disposable diaper 1 (absorbent article) in the deployed state, and the thickness direction DT is the thickness direction for the disposable diaper 1 (absorbent article) in the deployed state, the widthwise direction DW, lengthwise direction DL and thickness direction DT being in a mutually orthogonal relationship.
As shown in
In the disposable diaper 1, the top sheet 2′ is constructed of a nonwoven fabric 2 comprising a base 22 having a first surface 2a that faces the skin surface of the wearer and a second surface 2b on the opposite side from the first surface 2a, and extending out in an approximately flat manner, and a plurality of protrusions 21 protruding in the thickness direction DT from the first surface 2a of the base 22, and it is disposed on the skin side of the absorbent body 4 with the machine direction (MD direction) of the nonwoven fabric 2 being parallel to the lengthwise direction DL of the disposable diaper 1. According to the present invention, the direction in which the top sheet is disposed is not limited to this aspect, and for example, the top sheet may be disposed so that the MD direction of the nonwoven fabric composing the top sheet is parallel to the widthwise direction DW of the absorbent article.
The nonwoven fabric 2 according to an embodiment of the present invention will now be explained in further detail with reference to the accompanying drawings.
As shown in
As shown in
For this embodiment, as shown in
According to the present invention, the height of the protrusions (i.e., the distance between the first surface of the base and an imaginary plane parallel to the first surface that includes the points at the top surface sections that are most distant from the first surface of the base), is not particularly restricted so long as it does not interfere with the effect of the present invention, but from the viewpoint of cushioning properties and feel on the skin, they are in the range of, for example, 0.1 mm to 6.0 mm, preferably 0.2 mm to 5.0 mm and even more preferably 0.2 mm to 4.0 mm.
Moreover, as shown in
The nonwoven fabric 2 constructed in this manner is formed with the fiber density of the peripheral surface sections 21W that stand up in the thickness direction DT of the protrusions 21 being higher than the fiber density of the top surface sections 21T, and therefore even when pressure by body pressure or the like is applied in the thickness direction DT of the nonwoven fabric 2, since the peripheral surface sections 21W function as columns supporting the top surface sections 21T, the protrusions 21 are less likely to collapse, and even if the top surface sections 21T of the protrusions 21 collapse, since at least parts of the top surface perimeter portions 21C of the top surface sections 21T are constructed as the thickest sections 21CM having the greatest thickness in the nonwoven fabric 2, it is possible for collapse (deformation) of the top surface sections 21T to be restored by the resiliency of the thickest sections 21CM. This allows the nonwoven fabric 2 of this embodiment to adequately exhibit the satisfactory cushioning properties exhibited by the protrusions 21, for long periods. In addition, since the thickest sections 21CM have satisfactory resiliency and flexibility, even if the protrusions 21 have peripheral surface sections 21W with high fiber density, the hardness of the protrusions 21 is less likely to be felt and a satisfactory feel on the skin can be provided.
Incidentally, throughout the present description, the thickness of the nonwoven fabric is the degree of thickness of the nonwoven fabric at any point on the first surface, represented by the shortest distance between the first surface and the second surface on the opposite side. Consequently, the height of the protrusions (i.e., the shortest distance between the first surface of the base and an imaginary plane including the top surfaces of the top surface sections) is clearly distinguished from the thickness of the nonwoven fabric.
Furthermore, throughout the present description, the term “fiber density” refers to the number of cut cross-sections of the fiber per unit area when a cut surface of the nonwoven fabric is observed under magnification, and it can be measured according to the [Method of measuring fiber density] below.
The protrusions in the nonwoven fabric of the present invention will now be described in detail.
As shown in
As shown in
In the nonwoven fabric of the present invention, the thicknesses of the top surface sections of the protrusions are not particularly restricted so long as they are constructed so as to have the thickest sections at least at parts of the top surface perimeter portions, and any thickness may be used, as for the peripheral surface sections of the protrusions, or the base. From the viewpoint of the cushioning property, flexibility, feel on the skin, anti-rewetting property and liquid permeability of the nonwoven fabric, they are, for example, in the range of 0.1 mm to 10.0 mm and preferably in the range of 0.2 mm to 8.0 mm. In particular, the thicknesses at the thickest sections are in the range of 0.1 mm to 10.0 mm, for example, and preferably in the range of 0.3 mm to 8.0 mm.
As shown in
Also for this embodiment, the construction is such that the thickness of the top surface section 21T is maldistributed in one side in the lengthwise direction DL of the nonwoven fabric 2 in the planar view; however, according to the present invention there is no limitation to this construction, and for example, the construction may be such that the thickness of the top surface section 21T is maldistributed in any one direction in the widthwise direction DW of the nonwoven fabric in the planar view. Moreover, for this embodiment, all of the protrusions 21 have a similar distribution for the top surface section 21T; however, according to the present invention there is no limitation to this aspect, and for example, all of the protrusions may have different thickness distributions, or only some of the protrusions of the plurality of protrusions may have different thickness distributions. By thus adjusting the thickness distributions of the protrusions, it is possible to adjust the flow of fluid permeating through the nonwoven fabric.
According to yet another embodiment of the present invention, the construction may be such that the thicknesses of the top surface sections 21T are greater along the top surface perimeter portions 21C in the planar view.
In the nonwoven fabric of the present invention, the fiber density at the top surface sections of the protrusions is not particularly restricted so long it satisfies the condition of having lower fiber density than the peripheral surface sections without interfering with the satisfactory cushioning property and feel on the skin, and they may have any desired fiber density. Such a fiber density is in the range of 20 num/mm2 to 200 num/mm2, for example, and preferably in the range of 30 num/mm2 to 150 num/mm2, where one fiber cross-section is assumed to be a single fiber.
In the nonwoven fabric of the present invention, the thickest sections of the protrusions preferably have the lowest fiber density in the nonwoven fabric. If the thickest sections have the lowest fiber density in the nonwoven fabric, the resiliency and flexibility of the thickest sections will be relatively high, and therefore even when the top surface sections of the protrusions collapse, the collapse (deformation) of the top surface sections can be reliably restored, the hardness of the protrusions is even less likely to be felt, and a more satisfactory feel on the skin can be provided.
According to this embodiment, the peripheral surface sections 21W of the protrusions 21 are the sections corresponding to the sides of the essentially cylindrical protrusions 21, and they stand up in the thickness direction DT from the first surface 2a of the base 22 that extends flat and have an essentially tubular structure extending in the thickness direction DT, being connected to the top surface sections 21T at the edges on the side opposite the base 22. Furthermore, although the angle formed between the first surface 2a of the base 22 and the outer surface of the peripheral surface section (hereunder referred to as “standing angle”) is approximately 90° for this embodiment as shown in
According to the present invention, the thicknesses of the peripheral surface sections of the protrusions are not particularly restricted so long as the function as columns supporting the top surface sections is not inhibited, and any thickness may be used, as for the top surface sections of the protrusions, or the base. From the viewpoint of the resistance to collapse of the protrusions and the cushioning property, flexibility, feel on the skin, anti-rewetting property and liquid permeability, they are, for example, in the range of 0.1 mm to 10.0 mm and preferably in the range of 0.3 mm to 7.0 mm. Moreover, the peripheral surface sections may be constructed so as to have uniform thickness across the entirety, or they may be constructed so that the thickness gradually increases from the base side toward the top surface section side. In particular, when the peripheral surface sections are constructed so that the thickness gradually increases from the base side toward the top surface section side, the thickness at the parts of the peripheral surface sections connected to the top surface perimeter portions of the top surface sections (especially the thickest sections) is greater, increasing the resiliency and flexibility at those parts, and therefore collapse (deformation) of the top surface sections can be more reliably restored.
In the nonwoven fabric of the present invention, the fiber density at the peripheral surface sections of the protrusions is not particularly restricted so long it satisfies the condition of having higher fiber density than the top surface sections without interfering with the satisfactory cushioning property and feel on the skin, and they may have any desired fiber density. Such a fiber density is in the range of 30 num/mm2 to 150 num/mm2, for example, and preferably in the range of 50 num/mm2 to 120 num/mm2. Furthermore, the fiber density of the peripheral surface sections is preferably higher than the fiber density of the base. If the fiber density of the peripheral surface sections is higher than the fiber density of the base, pressure in the thickness direction applied from the first surface sides of the protrusions can be buffered by bending of the base to the second surface side, and therefore the protrusions will be even less likely to collapse and excellent flexibility can be imparted to the nonwoven fabric.
The construction other than the protrusions of the nonwoven fabric of the present invention will now be described.
In the nonwoven fabric of the present invention, the base has a first surface with the aforementioned protrusions and a second surface on the opposite side from the first surface, and it is the section extending essentially flat. The thickness of the base is not particularly restricted so long as it does not interfere with the satisfactory cushioning property, flexibility and liquid permeability, and any desired thickness may be employed. From the viewpoint of the cushioning property, flexibility, feel on the skin, anti-rewetting property and liquid permeability of the nonwoven fabric, it is in the range of 0.10 mm to 10.0 mm, for example, or in the range of preferably 0.15 mm to 7.0 mm and even more preferably 0.20 mm to 5.0 mm.
In the nonwoven fabric of the present invention, the fiber density of the base is not particularly restricted so long as it does not interfere with the satisfactory cushioning property, flexibility and liquid permeability, and it may have any desired fiber density. Such a fiber density is in the range of 10 num/mm2 to 150 num/mm2, for example, and preferably in the range of 20 num/mm2 to 100 num/mm2.
Furthermore, the fiber density of the base is preferably lower than the fiber density of the peripheral surface sections of the protrusions. If the fiber density of the base is lower than the fiber density of the peripheral surface sections of the protrusions, pressure in the thickness direction applied from the first surface sides of the protrusions can be buffered by bending of the base to the second surface side, and therefore the protrusions will be even less likely to collapse and excellent flexibility can be imparted to the nonwoven fabric. Furthermore, according to the present invention, the fiber density of the base is preferably lower than the fiber density of the top surface sections of the protrusions. If the fiber density of the base is lower than the fiber density of the top surface sections of the protrusions, pressure in the thickness direction applied from the first surface sides of the protrusions can be buffered by bending of the base to the second surface side before the top surface sections of the protrusions deform (collapse), and therefore the protrusions will be even much less likely to collapse and even more excellent flexibility can be imparted to the nonwoven fabric.
According to the present invention, the basis weight of the nonwoven fabric is not particularly restricted but is preferably 10 g/m2 to 100 g/m2 and more preferably 15 g/m2 to 50 g/m2. If the basis weight is 10 g/m2 or greater, sufficient surface strength as a nonwoven fabric will be obtained, and therefore when the nonwoven fabric has been applied to the top sheet of an absorbent article, for example, the top sheet will be less likely to tear during use of the absorbent article. Also, if the basis weight is 100 g/m2 or lower, stiffness will not be produced, and when the nonwoven fabric has been applied in a top sheet of an absorbent article, for example, the wearer will be less likely to have unpleasantness or discomfort occur during use of the absorbent article.
The fibers to be used in the nonwoven fabric of the present invention are not particularly restricted so long as they do not inhibit the satisfactory cushioning property and feel on the skin, and examples include natural fibers such as wool and cotton; regenerated fibers such as rayon and acetate; synthetic fibers composed using thermoplastic resins alone, including polyolefins such as polyethylene (PE) and polypropylene (PP); ethylene-vinyl acetate copolymer (EVA); ethylene-ethyl acrylate copolymer; ethylene-acrylic acid copolymer; ionomers; polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polylactic acid, and polyamides such as nylon, or composite fibers such as core-sheath, side-by-side or sea-island fibers composed using multiple different types of these thermoplastic resins. Core-sheath composite fibers preferably have a core-sheath structure wherein the core is polyethylene terephthalate (PET) and the sheath is polyethylene such as high-density polyethylene (HDPE) or low melting point polypropylene, and representative examples of such composite fibers include composite fibers with core/sheath=PET/HDPE, PET/PE, PP/PE and PP/low melting point PP. The form of such fibers is not particularly restricted, and fibers in the form of hollow fibers; irregular cross-sectional fibers that are flat, Y-shaped or the like, latent crimping or developed crimping type solid crimped fibers, or splittable fibers that split under a physical load such as a water stream, heat or embossing, may be suitably used. Such fibers may also be subjected to hydrophilicizing treatment. Each of the fibers mentioned above may be used alone, or two or more may be used in desired combinations.
A nonwoven fabric having a plurality of protrusions according to the present invention can be produced by using a nonwoven fabric produced by any desired production method, such as an air-through nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, thermal bond nonwoven fabric or meltblown nonwoven fabric, as the base material, and forming the plurality of protrusions on the surface of the base material; however, for more precise production of a nonwoven fabric having the plurality of protrusions, it is preferably produced by the production method described below.
An example of a production method for a nonwoven fabric according to the present invention will now be explained with reference to
In the method for producing a nonwoven fabric using this type of production apparatus 9, first the fibers F1 such as thermoplastic fibers or natural fibers, as the starting material, are supplied to the carding machine 91. At the carding machine 91, the supplied fibers F1 are opened and the basis weight of the fibers F1 is adjusted to the prescribed value.
The fiber matrix F2 that has left the carding machine 91 is then conveyed toward the surface of the suction drum 92. The suction drum 92 preferably has its interior formed in a hollow or porous manner, and the interior may be brought to a negative pressure by any desired suction means such as a vacuum pump. Also, as shown in
In addition, the outer peripheral surface of the suction drum 92 is covered by a pattern plate 93, and the fiber matrix F2 that has left the carding machine 91 is fed onto the pattern plate 93 that is rotating with the suction drum 92. The pattern plate 93 is composed of punching metal in which through-holes are formed in a prescribed pattern, with shapes complementary to the protrusions 21 of the nonwoven fabric 2 that will have a plurality of protrusions 21. Furthermore, as shown in
Also, as shown in
As shown in
The temperature and wind speed of the hot air blasted from the air jet nozzle 94 are each set to conditions so that protrusions having the structure specified above are formed, in consideration of the type of fibers composing the fiber matrix and the basis weight of the fiber matrix. The temperature conditions for the hot air are preferably set to be 20° C. to 70° C. higher than the melting point of the fibers composing the fiber matrix. For example, when the fibers composing the fiber matrix are PET/HDPE core-sheath composite fibers, the temperature of the hot air is preferably in the range of 80° C. to 400° C. The wind speed conditions for the hot air are in the range of 10.0 m/sec to 200.0 m/sec, for example, and preferably in the range of 20.0 m/sec to 150.0 m/sec, in consideration of the basis weight and thickness of the nonwoven fabric.
Also, as shown in
When heat setting of the fiber matrix F3 has been completed in this manner, a nonwoven fabric according to the present invention is obtained. The obtained nonwoven fabric may be cut to a desired size, according to the form in which it is to be used.
The nonwoven fabric of the present invention may be applied to any desired product that requires satisfactory cushioning properties and feel on the skin, and for example, it may be suitably used in an absorbent article such as a disposable diaper of the embodiment described above. Particularly when used as the top sheet of an absorbent article, the nonwoven fabric of the present invention can adequately exhibit satisfactory cushioning properties for long periods and can also provide a satisfactory feel on the skin, and therefore the wearer of the absorbent article can be provided with an excellent feel during wear for long periods.
Incidentally, an absorbent article to which the nonwoven fabric of the present invention is applied may be any of various types of absorbent articles, such as a pants-type disposable diaper according to the embodiment described above, or a sanitary napkin, tape-type disposable diaper or incontinence pad, for example. In addition, the absorbent article of the present invention is not restricted to the embodiments described above and the examples described below, and can incorporate appropriate combinations and modifications within a range that is not outside of the object and gist of the present invention.
The present invention will now be explained in greater detail using examples and comparative examples, with the understanding that the present invention is not limited only to the examples.
After opening PET/HDPE core-sheath composite fibers with a fineness of 1.3 dtex using an opener, the fibers were formed using a carding machine. The formed carded web was conveyed by a mesh conveyor, and supplied onto a pattern plate mounted on the outer peripheral surface of the suction drum. While rotating the suction drum, the carded web was suctioned into the through-holes of the pattern plate by negative pressure from suction holes formed in the outer peripheral surface of the suction drum, and the carded web was blasted with hot air at 180° C. at a wind speed of 50.0 m/sec, from an air jet nozzle situated on the lower side of the suction drum, thereby causing the carded web to run along the pattern plate to shape a plurality of protrusions on the carded web. Also, the web on which the plurality of protrusions had been shaped was conveyed to a heat setting machine and subjected to heat setting under hot air conditions with a temperature of 135° C. and a wind speed of 0.9 m/sec, after which the heat set web was wound up to obtain a nonwoven fabric for Example 1. The basis weight of the obtained nonwoven fabric was 25 g/m2.
A nonwoven fabric for Comparative Example 1 was obtained in the same manner as Example 1, except that the temperature and wind speed of the hot air blasted from the air jet nozzle were 143° C. and 29.2 m/sec, respectively. The basis weight of the obtained nonwoven fabric was 25 g/m2.
The cross-sectional structures of the protrusions (the cross-sectional structures along the center axis line VW in
Measurement of the fiber density was carried out in the same manner as the method described in Japanese Unexamined Patent Publication No. 2012-144835 (see paragraph [0041]). Specifically, the fiber density was measured according to the following [Method of measuring fiber density].
A cut surface of the nonwoven fabric is observed in an enlarged view using a scanning electron microscope (for example, a VE-7800 Real Surface View microscope by Keyence Corp.), with the center in the thickness direction of the nonwoven fabric as the center of observation (i.e., observation at a magnification allowing about 20 to 70 fiber cross-sections to be observed, which is normally a magnification of about 20× to 100×), and the number of cut cross-sections of fibers per fixed area (about 2 mm2) is counted. The counted number of cut cross-sections is converted to the number of cut cross-sections of fibers per 1 mm2, and recorded as the fiber density (num/mm2). This fiber density measurement is carried out at 3 locations, and the mean value is recorded as the fiber density for the sample.
Ten sample sheets are prepared by cutting the nonwoven fabric with a plurality of protrusions into 100 mm×100 mm quadrilateral shapes. The 10 prepared sample sheets are stacked and set on the measuring stage of an “Autograph AGS-1kNG” by Shimadzu Corp. One cycle of the compression test is carried out, under test conditions of chuck distance: 35 mm, compression speed: 25 mm/min, maximum load: 26 N. The sample sheet is compressed, the thickness (cm) of the sample sheet when the chuck distance has shortened is measured, and this thickness is divided by the sample sheet basis weight (g/cm2) to obtain the specific volume under compression (cm3/g) for the sample sheet. Also, the obtained specific volume under compression is divided by the number of protrusions in the sample sheet, and the resulting value is recorded as the specific volume under compression (cm3/g/protrusion) for each protrusion of the nonwoven fabric with the plurality of protrusions.
An electron micrograph of a cross-section of a protrusion of the nonwoven fabric of Example 1 is shown in
As shown in Table 1, the nonwoven fabric of Example 1 has a specific volume under compression per protrusion that is markedly larger compared to the nonwoven fabric of Comparative Example 1, indicating that the protrusions are less likely to collapse.
In addition, as shown
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-132160 | Jun 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/066957 | 6/7/2016 | WO | 00 |
