[0001]The present disclosure relates to spunbonded non-woven fabrics, sanitary materials, and methods for producing spunbonded non-woven fabrics.
Background technology
[0002]In recent years, non-woven fabrics have been widely used in various applications because of their excellent breathability and flexibility. Typical uses of the non-woven fabric include, for example, absorbent articles such as disposable diapers and sanitary napkins, sanitary masks, medical gauze, and base cloths for compresses.
　Such a non-woven fabric is required to have extensibility depending on the place where it is used.
[0003]
　For example, Japanese Patent Application Laid-Open No. 9-512313 proposes a technique relating to a close-contact non-woven fabric having good extensibility, which contains polyethylene and a propylene polymer as the non-woven fabric contained in the composite non-woven fabric.
　Further, International Publication No. 2014/050965 proposes a spunbonded nonwoven fabric composed of a composition containing two or more kinds of polypropylene having different melting points and a specific fatty acid amide as the flexible nonwoven fabric.
　Furthermore, according to International Publication No. 2017/006972, a propylene homopolymer having a relatively high melting point, polyethylene, and a specific carbon are further described as a spunbonded non-woven polymer having good heat-sealing properties at low temperatures and suitability for stretching. A span containing a polymer selected from the group consisting of a random copolymer of α-olefin and propylene having a number and a propylene homopolymer having a relatively low melting point and a specific mesopentad fraction and a racemicpentad fraction. Bonded non-woven materials have been proposed.
Outline of the invention
Problems to be solved by the invention
[0004]
　Although the close contact type extensible non-woven fabric described in JP-A-9-512313 is supposed to have a second extensible layer as a composite non-woven fabric, it is extensible to be used as a single non-woven fabric. Improvement may be required.
　The spunbonded non-woven fabric described in International Publication No. 2014/050965 may be required to have improved extensibility.
　For the spunbonded non-woven fabric described in International Publication No. 2017/006972, it may be required to further improve the extensibility.
[0005]
　According to one embodiment of the present invention, a spunbonded non-woven fabric having excellent extensibility and a sanitary material using the spunbonded non-woven fabric are provided without using a thermoplastic polyurethane elastomer.
　According to another embodiment of the present invention, there is provided a method for producing a spunbonded nonwoven fabric having excellent extensibility.
Means to solve problems
[0006]
　The disclosure includes the following embodiments:
<1>
　and a melting point 140 ° C. or more propylene homopolymer, density 0.941 g / cm 3 or more 0.970 g / cm 3 shows the polyethylene or less, the following polymer and below shown in (I) (II) A fiber containing at least one polymer selected from the group consisting of polymers and a fiber containing the fiber, the
　fiber having a sea-island structure, and an island phase in a cross section orthogonal to the axial direction of the fiber, having a diameter of 0.12 μm. A spunbonded non-woven fabric having an island phase ratio of more than 0.63 μm of 30% or more on a number basis.
　(I) Random copolymer of propylene and at least one selected from ethylene and α-olefin having 4 or more and 20 or less carbon atoms
　(II) A melting point of less than 120 ° C. satisfying the following (a) to (f). Propylene copolymer
(a) [mmmm] = 20 mol% or more and 60 mol% or less
(b) [rrrr] / (1- [mmmm])
≤0.1 (c) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] 2 ≦ 2.0
(e) Weight average molecular weight (Mw) = 10,000 or more and 200,000 or less
(f) Molecular weight distribution (Mw / Mn) <4
In (a) to (d), [mmmm] is a mesopentad fraction, [rrrr] is a racemic pentad fraction, and [rmrm] is a racemic mesolane semimesopentad fraction, [mm], [Rr] and [mr] are triad fractions, respectively, and Mn is a number average molecular weight.
<2>
　The spunbonded nonwoven fabric according to <1>, wherein the proportion of island phases having a diameter of 0.63 μm or more is 10% or less on a number basis.
<3>
　The spunbonded nonwoven fabric according to <1> or <2>, wherein the proportion of island phases having a diameter of less than 0.12 μm is 70% or less on a number basis.
<4>
　The spunbonded nonwoven fabric according to any one of <1> to <3>, wherein the content of the polyethylene is 1.0% by mass or more and 15.0% by mass or less with respect to the total amount of the fibers. ..
<5>
　The content of at least one polymer selected from the group consisting of the polymer shown in (I) and the polymer shown in (II) is 5.0% by mass or more and 30% by mass or more with respect to the total amount of the fibers. The spunbonded nonwoven fabric according to any one of <1> to <4>, which is 0.0% by mass or less.
<6>
　Any of <1> to <5>, wherein the content of the propylene homopolymer having a melting point of 140 ° C. or higher is 55.0% by mass or more and 90.0% by mass or less with respect to the total amount of the fibers. The spunbonded non-woven fabric according to one.
<7>
　When the fiber contains a fatty acid amide having 15 or more and 22 or less carbon atoms and the content of the fatty acid amide having 15 or more and 22 carbon atoms is 0.1% by mass or more and 5.0% by mass or less based on the total amount of the fiber. The spunbonded non-woven fabric according to any one of <1> to <6>.
<8> The
　polymer shown in (I) is a random copolymer containing at least a structural unit derived from propylene and a structural unit derived from ethylene, and is classified into any one of <1> to <7>. The spunbonded non-woven fabric described.
<9>
　A sanitary material containing the spunbonded non-woven fabric according to any one of <1> to <8>.
<10>
　and a melting point 140 ° C. or more propylene homopolymer, density 0.941 g / cm 3 or more 0.970 g / cm 3 shows the polyethylene or less, the following polymer and below shown in (I) (II) A composition containing at least one polymer selected from the group consisting of polymers is extruded from the extruder A and the extruder B in an amount of 85:15 to 55:45 on a mass basis (extrusion). Machine A: A method for producing a spunbonded non-woven fabric, which comprises extruding so as to become an extrusion machine B).
　(I) Random copolymer of propylene and at least one selected from ethylene and α-olefin having 4 or more and 20 or less carbon atoms
　(II) Melting point less than 120 ° C. satisfying the following (a) to (f) Propylene copolymer
(a) [mmmm] = 20 mol% or more and 60 mol% or less
(B) [rrrr] / (1- [mmmm]) ≦ 0.1
(c) [rmrm]> 2.5 mol%
(d) [mm] × [rr] / [mr] 2 ≦ 2.0
( e) Weight average molecular weight (Mw) = 10,000 or more and 200,000 or less
(f) In the molecular weight distribution (Mw / Mn) <4
(a) to (d), [mmmm] is the mesopentad fraction, and [rrrr. ] Is the Lasemipentad fraction, [rmrm] is the Lasemimesola semimesopentad fraction, and [mm], [rr] and [mr] are the triad fractions, respectively.
<11> The
　method for producing a spunbonded nonwoven fabric according to <10>, wherein the diameter A of the extruder A is larger than the diameter B of the extruder B.
The invention's effect
[0007]
　According to one embodiment of the present invention, a spunbonded nonwoven fabric having excellent extensibility and a sanitary material using the spunbonded nonwoven fabric are provided.
　According to another embodiment of the present invention, there is provided a method for producing a spunbonded nonwoven fabric having excellent extensibility.
A brief description of the drawing
[0008]
FIG. 1A is an image when a cross section of a fiber in the spunbonded nonwoven fabric of Example 2 is observed with a transmission electron microscope.
FIG. 1B is an image when a cross section of a fiber in the spunbonded nonwoven fabric of Example 3 is observed with a transmission electron microscope.
[Fig. 1C] Fig. 1C is an image when a cross section of a fiber in the spunbonded nonwoven fabric of Comparative Example 1 is observed with a transmission electron microscope.
FIG. 2 is a schematic view showing an example of a spunbonded nonwoven fabric manufacturing apparatus for manufacturing the spunbonded nonwoven fabric of the present invention.
FIG. 3 is a schematic view of a gear stretching device.
Mode for carrying out the invention
[0009]
　Hereinafter, embodiments of the present invention (hereinafter, also referred to as “the present embodiment”) will be described.
　However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified and clearly considered to be essential in principle. The same applies to the numerical values ​​and their ranges, and does not limit the present invention.
[0010]
　In the present specification, the term "process" is included in this term not only as an independent process but also as long as the purpose of the process is achieved even if it cannot be clearly distinguished from other processes.
　In the present specification, the content of each component in the composition is the sum of the plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition. Means quantity.
[0011]

　spunbonded nonwoven fabric of the present embodiment, the melting point of 140 ° C. or more propylene homopolymer, density 0.941 g / cm 3 or more 0.970 g / cm 3 and a polyethylene or less, the following (I) The fiber comprises a composition comprising the polymer shown in the above and at least one polymer selected from the group consisting of the polymer shown in the following (II), and the fiber has a sea-island structure, and the shaft of the fiber. A spunbonded non-woven fabric in which the proportion of island phases having a diameter of 0.12 μm or more and less than 0.63 μm is 30% or more based on the number of island phases in a cross section orthogonal to the direction.
　(I) Random copolymer of propylene and at least one selected from ethylene and α-olefin having 4 or more and 20 or less carbon atoms
　(II) A melting point of less than 120 ° C. satisfying the following (a) to (f). Propylene copolymer
(a) [mmmm] = 20 mol% or more and 60 mol% or less
(b) [rrrr] / (1- [mmmm])
≤0.1 (c) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] 2 ≦ 2.0
(e) Weight average molecular weight (Mw) = 10,000 or more and 200,000 or less
(f) Molecular weight distribution (Mw / Mn) <4
In (a) to (d), [mm mm] is a racemic pentad fraction, [rrrr] is a racemic pentad fraction, and [rmrm] is a racemic mesolacemic mesopentad fraction, [mm], [Rr] and [mr] are triad fractions, respectively.
　In addition, "at least one polymer selected from the group consisting of the polymer shown in (I) and the polymer shown in (II)" may be collectively referred to as "specific polymer".
[0012]
　The spunbonded nonwoven fabric of the present embodiment is composed of fibers composed of a propylene homopolymer having a relatively high melting point, the above-mentioned polyethylene, and a composition containing a specific polymer, and the fibers have a sea-island structure. However, the proportion of island phases having a diameter of 0.12 μm or more and less than 0.63 μm among the island phases in the cross section orthogonal to the axial direction of the fiber is 30% or more on a number basis.
　The present inventors include fibers having a sea-island structure as described above, and the proportion of island phases having a diameter of 0.12 μm or more and less than 0.63 μm among the island phases in the cross section orthogonal to the axial direction of the fibers is based on the number. A new finding was obtained that the extensibility of the obtained spunbonded non-woven fabric is enhanced when the content is 30% or more. It is presumed that the fibers having a sea-island structure as described above inhibits the orientation crystallization of polypropylene and enhances the extensibility, and the proportion of island phases having a diameter of 0.12 μm or more and less than 0.63 μm is within the above range. It is considered that the presence thereof more appropriately inhibits the orientation crystallization of polypropylene and further enhances the extensibility.
[0013]
　The spunbonded nonwoven fabric of the present embodiment is composed of fibers having a sea-island structure. The proportion of island phases having a diameter of 0.12 μm or more and less than 0.63 μm among the island phases in the sea-island structure of fibers is 30% or more on a number basis. From the viewpoint of improving extensibility, the proportion of island phases having a diameter of 0.12 μm or more and less than 0.63 μm is preferably 40% or more, more preferably 50% or more, and 55%. It is more preferably% or more.
[0014]
　The spunbonded nonwoven fabric of the present embodiment preferably has an island phase having a diameter of 0.63 μm or more of 10% or less based on the number of island phases in the sea-island structure of the fiber from the viewpoint of improving extensibility. Further, it is more preferably 4% or less, and further preferably 1% or less.
[0015]
　The spunbonded nonwoven fabric of the present embodiment preferably has an island phase having a diameter of less than 0.12 μm of 70% or less based on the number of island phases in the sea-island structure of the fiber from the viewpoint of improving extensibility. Further, it is more preferably 60% or less, and further preferably 45% or less. Further, the lower limit of the proportion of island phases having a diameter of less than 0.12 μm may be 5% or more on a number basis.
[0016]
　Here, the proportion of island fauna having a diameter of 0.63 μm or more, the proportion of island fauna having a diameter of 0.12 μm or more and less than 0.63 μm, and the proportion of island fauna having a diameter of less than 0.12 μm in the sea-island structure of fibers. Is measured, for example, by the following method.
[0017]
　The fibers are taken out from the spunbonded non-woven fabric and embedded in paraffin to prepare a measurement sample. Then, the measurement sample is placed in the microtome so that the direction orthogonal to the axial direction of the fiber and the blade are parallel, and sliced ​​along the direction orthogonal to the axial direction of the fiber. After carbon reinforcement is applied to the fibers obtained by slicing, the cross section of the fibers obtained by slicing is observed using a transmission electron microscope (TEM). A sea island pattern is confirmed on the cross section of the fiber. The diameter of the island phase within the observation range (cross section) is measured, with the continuous phase as the sea phase and the dispersed phase as the island phase. The number of island phases having a diameter of 0.63 μm or more, the number of island phases having a diameter of 0.12 μm or more and less than 0.63 μm, and the number of island phases having a diameter of less than 0.12 μm were counted. The ratio is calculated by dividing the number of island phases corresponding to each range by the number of island phases within the observation range (cross section). As the transmission electron microscope, a transmission electron microscope model: H-7650 manufactured by Hitachi High-Tech Co., Ltd. is used, and the observation magnification is set to 6000 times or 8000 times. The diameter of the island phase is determined by image analysis with Mac-View (Mountech Co., Ltd.). Specifically, the major axis and the minor axis of the island phase are measured, and the average value thereof is taken as the diameter.
[0018]
　It can be appropriately confirmed by a known method that each of the above components is contained in the composition or the fiber composed of the composition constituting the spunbonded nonwoven fabric of the present embodiment.
　The mesopentad fraction [mmmm], racemic pentad fraction [rrrr] and racemic mesolasemimesopentide fraction [rmrm] of the propylene homopolymer having a melting point of less than 120 ° C. in the polymer shown in (II), and , Triad fractions [mm], [rr] and [mr] are the methods proposed in "Macropolymers, 6,925 (1973)" by A. Zambeli et al., As detailed below. Can be calculated according to.
[0019]
　In the composition of the present embodiment, the content of polyethylene is preferably 1.0% by mass or more and 15.0% by mass or less, and more preferably 3.0% by mass or more and 12.0% by mass or less. More preferably, it is 6.0% by mass or more and 10.0% by mass or less.
　When the content of polyethylene in the composition is in the above range, the extensibility of the obtained spunbonded non-woven fabric can be improved.
[0020]
　Further, the polyethylene contained in the composition in the present embodiment has a density in the range of 0941 g / cm 3 or more and 0.970 g / cm 3 or less from the viewpoint of improving the strength of the spunbonded nonwoven fabric .
　When the density of polyethylene in the composition is within the above range, the strength of the obtained spunbonded non-woven fabric can be improved.
[0021]
　In the composition of the present embodiment, the content of the specific polymer is preferably 5.0% by mass or more and 30.0% by mass or less, and more preferably 10.0% by mass or more and 30.0% by mass or less. It is preferable, and more preferably 15.0% by mass or more and 25.0% by mass or less.
　When the content of polyethylene in the composition is in the above range, the extensibility of the obtained spunbonded non-woven fabric can be improved.
[0022]
　The specific polymer in the present embodiment is a random copolymer containing at least (I) a structural unit derived from propylene and a structural unit derived from ethylene, or a random copolymer, from the viewpoint of further improving the extensibility of the obtained spunbonded non-woven fabric. , (II), a propylene homopolymer having a melting point of less than 120 ° C. satisfying (a) to (f) is preferable, and a random copolymer containing at least a structural unit derived from propylene and a structural unit derived from ethylene is more preferable. A random copolymer consisting only of a structural unit derived from propylene and a structural unit derived from ethylene is more preferable.
[0023]
　In the composition of the present embodiment, the content of the propylene homopolymer having a melting point of 140 ° C. or higher is preferably 55.0% by mass or more and 90.0% by mass or less, and 60.0% by mass or more and 85.0% by mass or less. It is more preferably 65.0% by mass or more and 80.0% by mass or less.
　When the content of the propylene homopolymer having a melting point of 140 ° C. or higher in the composition is within the above range, the extensibility of the obtained spunbonded nonwoven fabric can be improved, and the strength and physical properties of the spunbonded nonwoven fabric are maintained within a good range. , It is easy to obtain a flexible non-woven fabric with a low basis weight.
[0024]
　The composition in the present embodiment preferably contains a fatty acid amide having 15 or more and 22 or less carbon atoms. When the composition contains a fatty acid amide having 15 or more and 22 or less carbon atoms, the fatty acid amide having 15 or more and 22 or less carbon atoms is adsorbed on the fiber surface of the spunbonded nonwoven fabric formed by the composition, and the fiber surface is modified. Will be done. As a result, the extensibility and flexibility of the non-woven fabric are further improved.
　The content of the fatty acid amide having 15 or more and 22 or less carbon atoms is preferably 0.1% by mass or more and 5.0% by mass or less, and 0.1% by mass or more and 3.0% by mass or less, based on the total amount of the composition. The following is more preferable, and 0.1% by mass or more and 1.0% by mass or less is further preferable.
[0025]
　The spunbonded nonwoven fabric of the present embodiment can be produced by a conventional method using the composition described in detail below.
　Here, the basis weight of the spunbonded nonwoven fabric of the present embodiment is not particularly limited.
　From the viewpoint of achieving both flexibility and strength, the nonwoven fabric of the present embodiment usually has a basis weight of 30 g / m 2 or less, more preferably 28 g / m 2 or less, and 25 g / m. 2 further preferably less, 5 g / m 2 or more 20 g / m 2 and most preferably in the following ranges. When the spunbonded nonwoven fabric of the present embodiment is applied to a sanitary material or the like described later, the basis weight of the spunbonded nonwoven fabric is preferably in the range of 5 g / m 2 or more and 19 g / m 2 or less. The basis weight of the spunbonded non-woven fabric is measured by, for example, the following method.
[0026]
　From the spunbonded non-woven fabric, 10 test pieces having a flow direction (MD) of 300 mm and a lateral direction (CD) of 250 mm are collected. In addition, the collection place is arbitrary 10 places. Next, the mass (g) of each of the collected test pieces is measured using a precision electronic balance (manufactured by Kensei Kogyo Co., Ltd.). Calculate the average value of the mass of each test piece. The calculated average value is converted into mass (g) per 1 m 2 , and the first decimal place is rounded off to obtain the basis weight of the spunbonded non-woven fabric [g / m 2 ].
[0027]
　The fibers constituting the spunbonded non-woven fabric usually have a fiber diameter of 50 μm or less, more preferably 40 μm or less, further preferably 30 μm or less, and most preferably 20 μm or less. The smaller the fiber diameter, the better the flexibility of the non-woven fabric, but from the viewpoint of handleability, manufacturing suitability, and suppression of fluffing of the obtained non-woven fabric, the fiber diameter is preferably 10 μm or more.
[0028]
[Physical characteristics of spunbonded non-woven fabric]
　The preferred physical characteristics of the spunbonded non-woven fabric of the present embodiment are listed below.
[0029]
(Heat sealability)
　One of the physical properties of the spunbonded nonwoven fabric of the present embodiment is heat sealability.
　Regarding the heat-sealing property of the spunbonded non-woven fabric, when two non-woven fabrics are overlapped and heat-sealed by a heat-sealing tester, it is preferable that the spunbonded non-woven fabric can be heat-sealed at a temperature of 180 ° C. or lower, and heat-sealed at a temperature of 160 ° C. or lower. It is more preferable that it can be done.
　Further, it is preferable that burning when heat-sealing under the above conditions, that is, discoloration due to heating is suppressed.
　The tensile peel strength of the two heat-sealed spunbonded non-woven fabrics is appropriately determined depending on the purpose of use of the spunbonded non-woven fabric, but is generally preferably 0.05 N / 20 mm or more, and 0.1 N / 20 mm or more. It is more preferably 20 mm or more. The tensile peel strength of the spunbonded non-woven fabric is measured by, for example, the following method.
[0030]
　From the spunbonded non-woven fabric, 10 test pieces having a flow direction (MD) of 100 mm and a lateral direction (CD) of 100 mm are collected. Next, two of these test pieces are overlapped so that the MD directions are the same, and heat seal is performed under the following conditions using a heat seal tester (product name: heat seal tester) manufactured by Tester Sangyo Co., Ltd. ..
　Seal bar width: 10.0 mm
　Seal pressure: 2.0 kg / cm 2
　Seal time: 1.0 second
　Seal temperature: Set the upper bar and lower bar to the same temperature (145 ° C, 155 ° C)
　Seal direction: Vertical to MD
[0031]
　Using a constant velocity tensile tester (manufactured by Toyo Seiki Co., Ltd., product name: stromagraph), perform a tensile peel test of each test piece heat-sealed under the above conditions, 5 sheets each under the following conditions. .. The average value of the values ​​obtained by the measurement is taken as the tensile peel strength.
　Specimen shape: Width 20 mm, length 50 mm
　Tensile speed: 30 mm / min
　Atmospheric temperature at the time of measurement: 23 ° C
[0032]
(Embossing Residual Rate)
　One of the physical properties of the spunbonded nonwoven fabric of the present embodiment is the embossing residual rate.
　The residual embossing rate of the spunbonded non-woven fabric after the stretching process is preferably 40% or more, more preferably 50% or more, and further preferably 70% or more.
　When the residual embossing rate after the stretching process is 40% or more, the tactile sensation of the spunbonded non-woven fabric becomes better.
　The embossing residual rate is measured by, for example, the following method.
[0033]
　From the spunbonded non-woven fabric, one test piece having a flow direction (MD) of 250 mm and a lateral direction (CD) of 200 mm is collected. The obtained test piece is inserted so that the roll rotation direction of the gear stretching device (in other words, the gear processing machine) as shown in FIG. 3 and the CD direction of the test piece coincide with each other, and the MD direction (that is, the flow of the non-woven fabric) A spunbonded nonwoven fabric gear-stretched in the direction) is obtained. The gear rolls mounted on the gear processing machine each have a diameter of 200 mm and a gear pitch of 2.5 mm, and the meshing depth of both rolls is adjusted to 5.5 mm. The morphology of the embossed portion of the gear-stretched spunbonded non-woven fabric is observed using a scanning electron microscope (SEM :: Scanning Electron Microscope). The embossing residual rate is calculated based on the following formula.
　Residual embossing = (number of unbroken embossed / number of observed embossed) x 100
　By observing the embossed part of the spunbonded non-woven fabric with the gear stretched, perforation at the embossed part, desorption of fibers, and embossing An embossed portion in which neither the portion nor the fiber breakage at the boundary thereof is confirmed is referred to as "unbroken embossed". "Number of unbroken embosses" means the number of unbroken embosses present within the observation range. The "observed number of embosses" means the number of embosses existing in the observation range. As the scanning electron microscope, an S-3500N scanning electron microscope manufactured by Hitachi, Ltd. is used, and the observation magnification is set to 100 times.
[0034]
(Flexibility) Flexibility
　is one of the physical characteristics of the spunbonded nonwoven fabric of the present embodiment.
　The flexibility of the spunbonded non-woven fabric has a great influence on the usability of the non-woven fabric. As the flexibility, there is flexibility by sensory evaluation by touch.
[0035]
(Maximum Elongation and Maximum Strength)
　One of the preferable physical properties of the spunbonded nonwoven fabric of the present embodiment is maximum elongation and maximum strength.
　The spunbonded non-woven fabric of the present embodiment preferably has a maximum elongation of 70% or more in at least one direction, more preferably 100% or more, and further preferably 140% or more.
　Further, the spunbonded nonwoven fabric of the present embodiment preferably has a maximum strength of 10 N / 50 mm or more in at least one direction, more preferably 15 N / 50 mm or more, and further preferably 20 N / 50 mm or more.
　Further, a spunbonded non-woven fabric having a property of having almost no elastic recovery is preferable.
　The maximum elongation and maximum strength of the spunbonded non-woven fabric are measured by, for example, the following methods.
[0036]
　From spunbonded non-woven fabric to JIS Z 8703 (ISO 554: 1976) in accordance with JIS L 1906 6.12.1 [A method] (transition to JIS L 1913: 2010, corresponding to ISO 9073-3: 1989). Collect 5 test pieces with a flow direction (MD) of 25 cm and a lateral direction (CD) of 5 cm in a constant temperature room with a temperature of 20 ± 2 ° C and a humidity of 65 ± 2% specified in (corresponding to the standard state of the test site). .. The obtained test piece is subjected to a tensile test using a tensile tester (Instron Japan Company Limited, Instron 5564 type) under the conditions of a chuck distance of 100 mm and a tensile speed of 300 mm / min. The tensile load is measured for 5 test pieces, and the average value of their maximum values ​​is taken as the maximum strength.
　Further, the elongation at the maximum strength is defined as the maximum elongation.
[0037]
　The spunbonded nonwoven fabric of the present embodiment can be produced by a conventional method using one or more of the compositions described in detail below.
[0038]
[Composition] As
　described above, the composition constituting the spunbonded nonwoven fabric of the present embodiment has a density of a propylene homopolymer having a melting point of 140 ° C. or higher (hereinafter, may be referred to as "specific polypropylene"). 0.941 g / cm 3 or more 0.970 g / cm 3 and less is polyethylene, at least one polymer (the specific polymer selected from the group consisting of polymers represented by (I) polymer and indicated by (II) ) And.
[0039]
　From the viewpoint of effectively achieving the object of the present embodiment, the total content of the specific polypropylene and the specific polymer in the total amount of the composition is preferably 80% by mass or more, preferably 90% by mass or more. More preferably, it is 95% by mass or more.
[0040]
[Propylene homopolymer having a melting point of 140 ° C. or higher (specific polypropylene)]
　A propylene homopolymer having a melting point of 140 ° C. or higher contains a structural unit derived from propylene and has a melting point of 140 ° C. or higher.
　The melting point of the propylene homopolymer is preferably 150 ° C. or higher.
[0041]
　The specific polypropylene is a crystalline resin manufactured or sold under the name of polypropylene, and can be used as long as it is a resin having a melting point (Tm) above 140 ° C. Examples of commercially available products include homopolymers of propylene having a melting point in the range of 155 ° C. or higher, preferably 157 ° C. or higher and 165 ° C. or lower.
[0042]
　The melting point of the specific polypropylene is the highest temperature side of the melting endothermic curve obtained by holding it at −40 ° C. for 5 minutes under a nitrogen atmosphere and then raising the temperature at 10 ° C./min using a differential scanning calorimeter (DSC). It is defined as the peak top of the peak observed in.
　Specifically, using a differential scanning calorimeter (DSC-7, manufactured by PerkinElmer), 5 mg of the sample was held at −40 ° C. for 5 minutes in a nitrogen atmosphere, and then the temperature was raised at 10 ° C./min. It can be obtained as the peak top of the peak observed on the highest temperature side of the obtained melt endothermic curve.
[0043]
　The melt flow rate (MFR: ASTM D 1238, 230 ° C., load 2160 g) of the specific polypropylene is not particularly limited as long as it can be melt-spun, but is usually 1 g / 10 minutes or more and 1000 g / 10 minutes or less, preferably 5 g / 10. It is in the range of minutes or more and 500 g / 10 minutes or less, more preferably 10 g / 10 minutes or more and 100 g / 10 minutes or less.
[0044]
　As the specific polypropylene, only one kind may be used in the composition, or two or more kinds having different melting points, molecular weights, crystal structures and the like may be used.
　The preferable content of the specific polypropylene with respect to the total amount of the composition is as described above.
[0045]
[Polyethylene]
　density that can be used in this embodiment is 0.941 g / cm 3 or more 0.970 g / cm 3 polyethylene or less, the ethylene homo-, such as high density polyethylene containing a structural unit derived from ethylene (so-called HDPE) Coalescence and the like can be mentioned.
　By using high-density polyethylene in the composition, extensibility, flexibility, and breaking strength can be further improved.
[0046]
　As for polyethylene, only one kind may be used in the composition, or two or more kinds having different melting points, molecular weights, crystal structures and the like may be used.
　The preferable content of polyethylene with respect to the total amount of the composition is as described above.
[0047]
[Specific Polymer]
　By using the composition containing the specific polymer in the present embodiment, the obtained spunbonded nonwoven fabric obtains extremely excellent stretchability while maintaining good flexibility and extensibility. be able to.
[0048]
[Polymer shown in (I): Random copolymer of propylene and at least one selected from ethylene and α-olefin having 4 or more and 20 or less carbon atoms] The polymer
　shown in (I) (hereinafter, The polymer (I)) contains a structural unit derived from propylene and a structural unit derived from ethylene and at least one olefin selected from α-olefins having 4 or more and 20 or less carbon atoms. It is a random copolymer.
　It is preferable that the polymer (I) is a random copolymer from the viewpoint that the obtained spunbonded non-woven fabric does not have a sticky feeling and the flexibility is improved.
　The polymer (I) is not particularly limited as long as it is a random copolymer containing the above-mentioned structural unit.
[0049]
　Examples of the monomer copolymerizable with propylene include ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 4-methyl-1-pentene, and other α-olefins having 4 to 20 carbon atoms. Can be mentioned.
　Among them, the monomer copolymerized with propylene is preferably ethylene or an α-olefin having 4 or more and 8 or less carbon atoms.
　The structural unit derived from the α-olefin contained in the polymer (I) may be only one kind or two or more kinds.
　Preferred examples of the polymer (I) include a propylene / 1-butene random copolymer, a propylene / ethylene random copolymer, a propylene / ethylene / 1-butene random copolymer, and the like.
[0050]
　From the viewpoint of effectively achieving the object of the present embodiment, the total ratio of the structural units derived from propylene and the structural units derived from the olefin other than propylene in the total structural units contained in the polymer (I) is It is preferably 80 mol% or more, more preferably 85 mol% or more, and further preferably 90 mol% or more.
[0051]
　The melting point of the polymer (I) is preferably 100 ° C. or higher, more preferably 130 ° C. or higher, and even more preferably 150 ° C. or higher.
　The melting point of the polymer (I) is determined by the melting endothermic curve obtained by holding the polymer (I) at −40 ° C. for 5 minutes under a nitrogen atmosphere and then raising the temperature at 10 ° C./min using a differential scanning calorimeter (DSC). It is defined as the peak top of the peak observed on the hottest side.
　Specifically, using a differential scanning calorimeter (DSC-7, manufactured by PerkinElmer), 5 mg of the sample was held at −40 ° C. for 5 minutes in a nitrogen atmosphere, and then the temperature was raised at 10 ° C./min. It can be obtained as the peak top of the peak observed on the highest temperature side of the obtained melt endothermic curve.
[0052]
　The crystallinity of the polymer (I) is preferably 15% or less, more preferably 10% or less, still more preferably 8% or less.
　The crystallinity of the polymer (I) was determined by melting heat absorption obtained by holding the polymer (I) at −40 ° C. for 5 minutes under a differential scanning calorimeter (DSC) and then raising the temperature at 10 ° C./min. It is calculated from the heat of fusion curve derived from the melting of the main component of the curve.
　Specifically, using a differential scanning calorimeter (DSC-7, manufactured by PerkinElmer), 5 mg of the sample was held at −40 ° C. for 5 minutes in a nitrogen atmosphere, and then the temperature was raised at 10 ° C./min. Of the obtained heat absorption curves for melting, it can be calculated using the following formula from the heat of fusion curve derived from the melting of the main component.
　Crystallinity = (ΔH / ΔH0) × 100 (%) In the
　formula, ΔH is the amount of heat of fusion (J / g) obtained from the heat of fusion curve derived from the melting of the main components of the α-olefin copolymer containing ethylene and propylene. ), And ΔH0 is the amount of heat of fusion (J / g) of the complete crystal of the main component. That is, when the main component is ethylene, ΔH0 is 293 J / g, and when the main component is propylene, ΔH0 is 210 J / g.
[0053]
　The polymer (I) preferably has a tensile elastic modulus of 100 MPa or less as measured by a method compliant with JIS K 7161 (transitioned to JIS K 7161-1: 2014, corresponding to ISO 527-1: 2012). , 40 MPa or less, more preferably 25 MPa or less.
[0054]
　The melt flow rate (MFR: ASTM D 1238, 230 ° C., load 2160 g) of the polymer (I) is usually 1 g / 10 minutes or more and 100 g / 10 minutes from the viewpoint of obtaining good spinnability and excellent drawing processability. It is preferably in the following range, more preferably in the range of 5 g / 10 minutes or more and 100 g / 10 minutes or less, and further preferably in the range of 30 g / 10 minutes or more and 70 g / 10 minutes or less.
[0055]
　The ratio of the weight average molecular weight (Mw) of the polymer (I) to the number average molecular weight (Mn): Mw / Mn (molecular weight distribution) is usually 1.5 or more and 5.0 or less. The molecular weight distribution (Mw / Mn) of the polymer (I) is more preferably 1.5 or more and 3.0 or less in that a composite fiber having better spinnability and particularly excellent fiber strength can be obtained.
　In addition, good spinnability means that yarn breakage does not occur during ejection and drawing of the polymer (I) from the spinning nozzle, and filament fusion does not occur.
　Mw and Mn of the polymer (I) can be measured by a known method by GPC (gel permeation chromatography).
　The details of the measurement method will be described later.
[0056]
[Polymer represented by (II): Propylene homopolymer satisfying the following requirements (a) to (f)] The polymer
　represented by (II) (hereinafter, may be referred to as polymer (II)) is described below. It is a polymer that satisfies the requirements of (a) to (f).
　First, the requirements (a) to (f) will be described.
[0057]
(A) [mmmm] = 20 mol% or more and 60 mol% or less When
　the mesopentad fraction [mmmm] of the polymer (II) is 20 mol% or more, the occurrence of stickiness is suppressed and it is 60 mol% or less. Then, the degree of crystallinity does not become too high, so that the elastic recovery property becomes good.
　The mesopentad fraction [mm mm] is preferably 30 mol% or more and 50 mol% or less, and more preferably 40 mol% or more and 50 mol% or less.
[0058]
　The mesopentad fraction [mmmm], the racemic pentad fraction [rrrr] and the racemic meso-lame mesopentad fraction [rmrm], which will be described later, are described in "Macromolecules, 6,925 (1973)" by A. Zambeli et al. The meso-parts, racemic, and racemic meso-meso-parts per pentad in the polypropylene molecular chain measured by the signal of the methyl group in the 13 C-NMR spectrum , according to the method proposed in. .. The larger the mesopentad fraction [mm mm], the higher the stereoregularity. Further, the triad fractions [mm], [rr] and [mr] described later are also calculated by the above method.
[0059]
The measurement of 　the 13 C-NMR spectrum can be carried out under the following equipment and conditions according to the peak attribution proposed in "Macromomolecules, 8, 687 (1975)" by A. Zambeli et al. can.
[0060]
Equipment: JNM-EX400 type 13 C-NMR equipment manufactured by JEOL Ltd.
Method: Proton complete decoupling method
Concentration: 220 mg / ml
Solvent: 1,2,4-trichlorobenzene and heavy benzene 90:10 (volume ratio) Mixing solvent
temperature: 130 ° C.
Pulse width: 45 °
Pulse repetition time: 4 seconds
integration: 10000 times
[0061]
[Calculation formula]
M = m / S × 100
R = γ / S × 100
S = Pββ + Pαβ + Pαγ
S: Signal intensity of side chain methyl carbon atom of all propylene units
Pββ: Signal intensity of 19.8 ppm or more and 22.5 ppm or less
Pαβ: Signal intensity of
18.0 ppm or more and 17.5 ppm or less Pαγ: Signal intensity of 17.5 ppm or more and 17.1 ppm or less
γ
: Lasemipentad chain: Signal intensity of 20.7 ppm or more and 20.3 ppm or less m: Mesopentad chain: 21.7 ppm Signal intensity of 22.5 ppm or less In
　addition, M represents the abundance of the mesopentad chain in propylene, and R represents the abundance of the racemipentad chain in propylene.
[0062]
(B) The value of [rrrr] / (1- [mmmm])
　≤0.1 [rrrr] / [1-mmmm] is obtained from the fractions of the racemic pentad unit and the mesopentad unit, and is obtained from the polymer ( 1- [mmmm]). It is an index showing the uniformity of the regularity distribution of the propylene-derived constituent units in II). When this value becomes large, it becomes a mixture of highly regular polypropylene and atactic polypropylene like conventional polypropylene manufactured by using an existing catalyst system, which causes stickiness.
　When [rrrr] / (1- [mmmm]) of the polymer (II) is 0.1 or less, the stickiness of the obtained spunbonded non-woven fabric is suppressed. From such a viewpoint, [rrrr] / (1- [mmmm]) is preferably 0.05 or less, more preferably 0.04 or less.
[0063]
(C) [rmrm]> 2.5 mol% When
　the racemic mixture semi-meso fraction [rmrm] of the polymer (II) exceeds 2.5 mol%, the randomness of the polymer (II) Is increased, and the elastic recovery of the spunbonded non-woven fabric is further improved. [Rmrm] is preferably 2.6 mol% or more, and more preferably 2.7 mol% or more. The upper limit of the racemic mixture of the polymer (II) [rmrm] is usually about 10 mol%.
[0064]
(D) [mm] × [rr] / [mr] 2 ≦ 2.0
　[mm] × [rr] / [mr] 2 indicates the index of randomness of the polymer (II), and this value is When it is 2.0 or less, the elastic nonwoven fabric can obtain sufficient elastic recovery and suppress stickiness. The closer [mm] × [rr] / [mr] 2 is to 0.25, the higher the randomness. From the viewpoint of obtaining the above-mentioned sufficient elastic recovery, [mm] × [rr] / [mr] 2 is preferably more than 0.25 and 1.8 or less, and more preferably 0.5 or more and 1.5 or less. Is.
[0065]
(E) Weight average molecular weight (Mw) = 10,000 or more and 200,000 or less When the
　weight average molecular weight of the polymer (II) which is a propylene homopolymer is 10,000 or more, the polymer (II) Since the viscosity is not too low and is appropriate, yarn breakage during production of the spunbonded nonwoven fabric obtained by the composition is suppressed. When the weight average molecular weight is 200,000 or less, the viscosity of the polymer (II) is not too high and the spinnability is improved.
　The weight average molecular weight is preferably 30,000 or more and 150,000 or less, and more preferably 50,000 or more and 150,000 or less.
　The method for measuring the weight average molecular weight of the polymer (II) will be described later.
[0066]
(F) In the molecular weight distribution (Mw / Mn) <4
　polymer (II), when the molecular weight distribution (Mw / Mn) is less than 4, the occurrence of stickiness in the obtained spunbonded nonwoven fabric is suppressed. This molecular weight distribution is preferably 1.5 or more and 3 or less.
　The weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured by a gel permeation chromatography (GPC) method under the following equipment and conditions. The molecular weight distribution (Mw / Mn) is a value calculated from the number average molecular weight (Mn) and the weight average molecular weight (Mw) measured in the same manner.
[0067]
[GPC measuring device]
Column: TOSO GMHHR-H (S) HT
detector: RI detector for liquid chromatogram WATERS 150C
[Measuring conditions]
Solvent: 1,2,4-trichlorobenzene
Measurement temperature: 145 ° C.
Flow velocity: 1. 0
ml / min Sample concentration: 2.2 mg / ml
Injection volume: 160 μl
Calibration curve: Universal Calibration
analysis program: HT-GPC (Ver.1.0)
[0068]
　It is preferable that the polymer (II) further satisfies the following requirement (g).
(G) Melting point (Tm-D) = 0 ° C. or higher and 120 ° C. or lower The melting point (Tm-D) of the
　polymer (II) is -10 under a nitrogen atmosphere using a (g) differential scanning calorimeter (DSC). It is a melting point (Tm-D) defined as the peak top of the peak observed on the highest temperature side of the melting endothermic curve obtained by holding at ° C. for 5 minutes and then raising the temperature at 10 ° C./min.
　When the melting point (Tm-D) of the polymer (II) is 0 ° C. or higher, the occurrence of stickiness of the spunbonded nonwoven fabric formed by the composition is suppressed, and when it is 120 ° C. or lower, sufficient elastic recovery is obtained. can get. From this point of view, the melting point (Tm-D) is more preferably 0 ° C. or higher and 100 ° C. or lower, and further preferably 30 ° C. or higher and 100 ° C. or lower.
[0069]
　The melting point (Tm-D) is 10 ° C./min after holding 10 mg of the sample in a nitrogen atmosphere at -10 ° C. for 5 minutes using a differential scanning calorimeter (DSC-7, manufactured by PerkinElmer). It can be obtained as the peak top of the peak observed on the highest temperature side of the melting endothermic curve obtained by raising the temperature in.
[0070]
　The polymer (II) is usually 100 g / 10 for 1 g / 10 minutes or more because the melt flow rate (MFR: ASTM D 1238, 230 ° C., load 2160 g) obtains good spinnability and excellent drawability. It is preferably in the range of minutes or less, more preferably in the range of 5 g / 10 minutes or more and 100 g / 10 minutes or less, and further preferably in the range of 30 g / 10 minutes or more and 70 g / 10 minutes or less.
[0071]
　The polymer (II) can be synthesized, for example, by using a homogeneous catalyst, a so-called metallocene catalyst, as described in International Publication No. 2003/0871772.
[0072]
[Additives] The
　composition contains, as an optional component, an antioxidant, a heat-resistant stabilizer, a weather-resistant stabilizer, an antistatic agent, a slip agent, an antifogging agent, a lubricant, a dye, etc., as long as the object of the present embodiment is not impaired. It may contain various known additives such as pigments, natural oils, synthetic oils, waxes and fatty acid amides.
[0073]
As
　described above, the [fatty acid amide] composition preferably contains a fatty acid amide having 15 or more and 22 or less carbon atoms.
　When the composition contains fatty acid amide, the fatty acid amide is adsorbed on the fiber surface of the spunbonded non-woven fabric formed by the composition, and the fiber surface is modified to further improve flexibility, tactile sensation, blocking resistance and the like. , It is considered that the adhesion of the non-woven fabric fibers to the members of various rotating devices and the like in the device used in the embossing process and the like is more effectively suppressed.
[0074]
　Examples of fatty acid amides having 15 or more and 22 or less carbon atoms include fatty acid monoamide compounds, fatty acid diamide compounds, saturated fatty acid monoamide compounds, and unsaturated fatty acid diamide compounds.
　The carbon number of the fatty acid amide in the present specification means the carbon number contained in the molecule, and the carbon in -CONH constituting the amide is also included in the carbon number. The number of carbon atoms of the fatty acid amide is more preferably 18 or more and 22 or less.
[0075]
　Specific examples of the fatty acid amides that can be used in the composition include palmitic acid amides (16 carbon atoms), stearic acid amides (18 carbon atoms), oleic acid amides (18 carbon atoms), and erucic acid amides (22 carbon atoms). ) And so on.
　Only one type of fatty acid amide may be used in the composition, or two or more types may be used.
　The preferred content of the fatty acid amide with respect to the total amount of the composition is as described above.
[0076]

　The spunbonded nonwoven fabric of the present embodiment can be produced by a conventional method using one or more of the above-mentioned compositions.
　Specifically, the spunbonded nonwoven fabric of the present embodiment is preferably produced by the method for producing the spunbonded nonwoven fabric of the present embodiment shown below.
　Method for producing a spunbonded nonwoven fabric of the present embodiment, the propylene homopolymer of above the melting point 140 ° C., density 0.941 g / cm 3 or more 0.970 g / cm 3 and a polyethylene or less, the specific polymer, the The composition to be contained is extruded from the extruder A and the extruder B so that the amount of the composition extruded is 85:15 to 55:45 (extruder A: extruder B) on a mass basis. ..
[0077]
　The present inventors have obtained a new finding that the extensibility of the obtained spunbonded non-woven fabric is enhanced by extruding the resin composition from the two extruders at different ratios as described above. It is considered that by extruding the resin composition from the two extruders at different ratios as described above, the orientation crystallization of polypropylene is more appropriately inhibited and the extensibility is further enhanced.
[0078]
　In the method for producing a spunbonded nonwoven fabric of the present embodiment, the extensibility of the spunbonded nonwoven fabric can be improved by using two pushers A and B.
　From the viewpoint of improving the extensibility of the spunbonded non-woven fabric, the amount of the composition extruded from the extruder A and the extruder B is preferably 80:20 to 55:45, and is 75:25 to 55:45. Is more preferable.
[0079]
　In the method for producing a spunbonded nonwoven fabric of the present embodiment, the same composition is mixed in each extruder from the extruder A and the extruder B (hereinafter, also referred to as “mixing step”), and the same composition melted through the mixing step. It is preferable that an object is supplied to the nozzle. Then, the molten resins discharged from the extruder A and the extruder B are merged until they reach the mouthpiece, and the yarn is formed by a nonwoven fabric forming step of obtaining a nonwoven fabric by a spunbond method.
[0080]
　It is preferable that the diameter A of the extruder A of the present embodiment is larger than the diameter B of the extruder B from the viewpoint of improving the extensibility of the spunbonded nonwoven fabric.
　Here, the diameter indicates the outlet portion of the extruder (hereinafter, also referred to as “extruder”), that is, the diameter of the flow path connected to the nozzle. Further, the shape of the mouthpiece of the extruder is not particularly limited.
[0081]
[Mixing Step]
　In the mixing step, a propylene homopolymer of above the melting point 140 ° C., density 0.941 g / cm 3 or more 0.970 g / cm 3 composition were mixed with polyethylene or less, the specific polymer, the Get things.
　In addition, the components other than polyethylene used in this step, that is, the propylene homopolymer having a melting point of 140 ° C. or higher, the specific polymer, and the additive (optional component such as fatty acid amide having 15 or more and 22 or less carbon atoms) are each used. It may be in a molten state or may be a solid.
　This step may be performed in the extruder used in the non-woven fabric forming step.
[0082]
　The content of polyethylene used in this step is preferably 1.0% by mass or more and 15.0% by mass or less with respect to the total amount of the composition.
　The content of the specific polymer used in this step is preferably 5% by mass or more and 30% by mass or less with respect to the total amount of the composition.
　Further, the content of the propylene homopolymer having a melting point of 140 ° C. or higher used in this step is preferably 55.0% by mass or more and 90.0% by mass or less with respect to the total amount of the composition.
[0083]
　Further, this step is preferably a step of further mixing a fatty acid amide having 15 or more and 22 or less carbon atoms to obtain a composition.
　In other words, this step, a propylene homopolymer of above the melting point 140 ° C., density 0.941 g / cm 3 or more 0.970 g / cm 3 and a polyethylene or less, and the specific polymer, having 15 to 22 carbon atoms It is preferable that the step is to obtain a composition by mixing with a fatty acid amide.
　The content of the fatty acid amide having 15 or more and 22 or less carbon atoms used in this step is preferably 0.1% by mass or more and 5.0% by mass or less with respect to the total amount of the composition.
[0084]
[Nonwoven fabric forming step] In the
　nonwoven fabric forming step, a nonwoven fabric is obtained from the composition obtained in the mixing step by a spunbond method.
　In this step, for example, a non-woven fabric is obtained by the following method.
　That is, the same composition is melted using two extruders, and the same melted composition is melt-spun using a spunbonded non-woven fabric molding machine having a plurality of spinning caps, and long fibers formed by spinning. This is a method in which the fibers are cooled as necessary, then deposited on the collection surface of the spunbonded non-woven fabric molding machine, and heat-pressurized with an embossing roll.
[0085]
　The melting temperature of the composition is not particularly limited as long as it is equal to or higher than the softening temperature or melting temperature of the composition used for spinning and lower than the thermal decomposition temperature, and may be appropriately determined depending on the physical characteristics of the composition to be used.
　The temperature of the spinneret depends on the composition used, but since the composition used in this step is a composition having a large content of the propylene homopolymer, it is preferably 180 ° C. or higher and 240 ° C. or lower, preferably 190 ° C. It is more preferably 230 ° C. or lower, and further preferably 200 ° C. or higher and 225 ° C. or lower.
[0086]
　When cooling the spun long fibers, it is preferable to use a method of applying cooling air to the long fibers so that the long fibers are stretched while being cooled.
　The temperature of the cooling air for cooling the spun long fibers is not particularly limited as long as the temperature at which the composition solidifies. Generally, the temperature of the cooling air is preferably 5 ° C. or higher and 50 ° C. or lower, more preferably 10 ° C. or higher and 40 ° C. or lower, and further preferably 15 ° C. or higher and 30 ° C. or lower.
　When the spun long fibers are stretched by cooling air, the air velocity of the cooling air is usually in the range of 100 m / min or more and 10,000 m / min or less, preferably 500 m / min or more and 10,000 m / min or less.
[0087]
[Nonwoven Fabric Laminate]
　The spunbonded non-woven fabric of the present embodiment may be used alone, or may be a non-woven fabric laminate in which the spunbonded non-woven fabric of the present embodiment and another layer are laminated, depending on the purpose. A non-woven fabric laminate containing a plurality of spunbonded non-woven fabrics of the present embodiment may be used.
　When the spunbonded non-woven fabric of the present embodiment is used to form a non-woven fabric laminate, the layers other than the spunbonded non-woven fabric of the present embodiment may be one layer or two or more layers.
[0088]
　Specific examples of the layer other than the spunbonded non-woven fabric of the present embodiment include a knitted fabric, a woven fabric, a non-woven fabric other than the spunbonded non-woven fabric of the present embodiment, and a film.
　The method of further laminating (bonding) another layer to the spunbonded nonwoven fabric of the present embodiment is not particularly limited, and is a heat fusion method such as thermal embossing or ultrasonic fusion, a machine such as a needle punch or a water jet. Various methods such as a target entanglement method, a method using an adhesive such as a hot melt adhesive and a urethane adhesive, and an extruded laminate can be adopted.
[0089]
　Examples of other non-woven fabrics that can be laminated with the spunbonded non-woven fabric of the present embodiment to form a non-woven fabric laminate include spunbonded non-woven fabrics other than the spunbonded non-woven fabric of the present embodiment, melt blown non-woven fabrics, wet non-woven fabrics, dry non-woven fabrics, and dry pulp non-woven fabrics. Various known non-woven fabrics such as flash-spun non-woven fabric and spread non-woven fabric can be mentioned.
　These non-woven fabrics may be stretchable non-woven fabrics or non-stretchable non-woven fabrics.
　Here, the non-stretchable non-woven fabric means a non-woven fabric that does not generate a return stress after being stretched in MD (that is, the flow direction of the non-woven fabric, the vertical direction) or CD (that is, the direction perpendicular to the flow direction of the non-woven fabric, the lateral direction). ..
[0090]
　As the film capable of forming a nonwoven fabric laminate by laminating with the spunbonded nonwoven fabric of the present embodiment, a breathable film, that is, a moisture-permeable film is preferable when the nonwoven fabric laminate requires breathability.
　As the breathable film, a film made of a thermoplastic elastomer such as a moisture-permeable polyurethane elastomer, a polyester elastomer, or a polyamide elastomer, or a film made of a thermoplastic resin containing inorganic fine particles or organic fine particles is stretched and made porous. Examples thereof include various known breathable films such as a porous film.
　As the thermoplastic resin used for the porous film, polyolefins such as high-pressure low-density polyethylene, linear low-density polyethylene (so-called LLDPE), high-density polyethylene, polypropylene, polypropylene random copolymer, and a combination thereof are preferable.
　When the nonwoven fabric laminate does not require breathability, a film made of one or more thermoplastic resins selected from polyethylene, polypropylene and the like can be used.
[0091]
　Examples of the heat fusion method for heat-sealing a part of the non-woven fabric laminate include various known methods, for example, a method using means such as ultrasonic waves, heat embossing using an embossing roll, and hot air through. Be done.
　Above all, it is preferable that the heat fusion method is heat embossing because the long fibers are efficiently stretched when the non-woven fabric laminate is stretched.
[0092]
　When a part of the non-woven fabric laminate is heat-sealed by heat embossing, the embossed area ratio is usually 5% or more and 30% or less, preferably 5% or more and 20% or less, and the non-embossed unit area is 0.5 mm 2 or more. It is preferably in the range of 4 mm 2 or more and 40 mm 2 or less.
　The non-embossed unit area is the maximum area of ​​a quadrangle inscribed in embossing in the smallest unit non-embossed portion surrounded by embossed portions on all sides. Examples of the engraved shape include a circle, an ellipse, an oval, a square, a rhombus, a rectangular shape, a square, and a continuous shape based on these shapes.
[0093]
　By stretching the obtained non-woven fabric laminate, a stretchable non-woven fabric laminate having elasticity can be obtained.
　The method of stretching is not particularly limited, and a conventionally known method can be applied.
　The method of stretching may be a method of partially stretching or a method of totally stretching. Further, the method of stretching may be a method of uniaxial stretching or a method of biaxial stretching.
　Examples of the method of stretching in the flow direction (MD) of the machine include a method of passing partially fused mixed fibers through two or more nip rolls. At this time, the partially fused nonwoven fabric laminate can be stretched by increasing the rotation speed of the nip roll in the order of the flow direction of the machine. It is also possible to perform gear stretching processing using a gear stretching device.
[0094]
　The draw ratio is preferably 50% or more, more preferably 100% or more, further preferably 200% or more, and preferably 1000% or less, more preferably 400% or less.
[0095]
　In the case of uniaxial stretching, it is preferable that either the stretching ratio in the flow direction (MD) of the machine or the direction perpendicular to the stretching ratio (CD) satisfies the stretching ratio. In the case of biaxial stretching, it is preferable that at least one of the flow direction (MD) of the machine and the direction perpendicular to the flow direction (CD) satisfies the stretching ratio.
[0096]
　By stretching at such a draw ratio, the elastic long fibers in the spunbonded nonwoven fabric are stretched, and the non-stretchable long fibers are plastically deformed and stretched according to the draw ratio.
　Similarly, in the other layers to be laminated, the elastic layer is elastically deformed, and the non-elastic layer is plastically deformed.
　When forming a non-woven fabric laminate, an elastic layer and a non-elastic layer are laminated and stretched, and then when stress is released, an elastic layer (specifically, a layer is formed). The long fibers) recover their elasticity, and the long fibers having no elasticity can bend without recovering their elasticity, and a feeling of bulkiness can be expressed in the non-woven fabric laminate. Since the plastically deformed long fibers become thin, the flexibility and the tactile sensation are improved, and the non-woven fabric laminate can be provided with a non-stretching function.
[0097]

　The spunbonded non-woven fabric of the present embodiment can be suitably used as a sanitary material, for example. Examples of sanitary materials include absorbent articles such as paper diapers and sanitary napkins; medical sanitary materials such as packaging bags, medical gauze, towels, medical gowns, surgical drapes, and wound dressings; sanitary masks and the like. ..
　Further, the spunbonded non-woven fabric of the present embodiment can be suitably used as a cosmetic material such as a cosmetic face mask and a cosmetic puff.
　Further, the spunbonded nonwoven fabric of the present embodiment can be suitably used as, for example, an industrial material typified by a filter, a sound absorbing material, and an oil adsorbent.
　Nonwoven fabrics with excellent extensibility are suitable for applications in contact with the skin because they tend to give a fluffy feel. Therefore, among these applications, it can be more preferably used as a sanitary material.
[0098]
　When the spunbonded non-woven fabric of the present embodiment is used for the above-mentioned applications, the spunbonded non-woven fabric of the present embodiment may be used in a single layer, or the spunbonded non-woven fabric of the present embodiment may be laminated and used. The spunbonded non-woven fabric of No. 1 and another layered article may be laminated and used. That is, it may be used as a non-woven fabric laminate containing the spunbonded non-woven fabric of the present embodiment. Examples of other layered articles include non-woven fabrics other than the spunbonded non-woven fabric of the present embodiment, films, cotton, felt and the like.
[0099]

　The sanitary material of the present embodiment includes the spunbonded nonwoven fabric of the present embodiment described above.
　The spunbonded nonwoven fabric of the present invention has excellent extensibility. Therefore, the spunbonded non-woven fabric of the present embodiment is suitably used as a sanitary material.
[0100]
　The sanitary material may include the spunbonded non-woven fabric of the present embodiment as a non-woven fabric laminate containing the spunbonded non-woven fabric of the present embodiment and other layers.
Example
[0101]
　Hereinafter, embodiments of the present invention will be described in more detail based on examples, but the present invention is not limited to these examples, which are embodiments of the present invention.
　Physical property values ​​and the like in Examples and Comparative Examples were measured by the following methods.
[0102]
(1)
　Fibers were taken out from the island phase diameter [μm] spunbonded non-woven fabric and embedded in paraffin to prepare a measurement sample. Then, the measurement sample was placed in the microtome so that the direction orthogonal to the axial direction of the fiber and the blade were parallel, and sliced ​​along the direction orthogonal to the axial direction of the fiber. Then, after carbon reinforcement was applied to the fiber obtained by slicing, the cross section of the fiber obtained by slicing was observed using a transmission electron microscope (TEM). A sea island pattern was confirmed on the cross section of the fiber. The diameter of the island phase within the observation range (cross section) was measured, with the continuous phase as the sea phase and the dispersed phase as the island phase. The number of island phases having a diameter of 0.63 μm or more, the number of island phases having a diameter of 0.12 μm or more and less than 0.63 μm, and the number of island phases having a diameter of less than 0.12 μm were counted. The ratio was calculated by dividing the number of island phases corresponding to each range by the number of island phases within the observation range (cross section).
　Here, as the transmission electron microscope, a transmission electron microscope model: H-7650 manufactured by Hitachi High-Tech Co., Ltd. was used. The observation magnification was 6000 times or 8000 times.
　The diameter of the island phase was determined by image analysis with Mac-View (Mountech Co., Ltd.). Specifically, the major axis and the minor axis of the island phase were measured, and the average value was taken as the diameter.
[0103]
(2) From the basis weight [g / m 2 ]
　spunbonded non-woven fabric, 10 test pieces having a flow direction (MD) of 300 mm and a lateral direction (CD) of 250 mm were collected. In addition, the collection place was arbitrary 10 places. Next, the mass (g) of each of the collected test pieces was measured using a precision electronic balance (manufactured by Kensei Kogyo Co., Ltd.). The average value of the mass of each test piece was calculated. The calculated average value was converted into mass (g) per 1 m 2 , and the first decimal place was rounded off to obtain the basis weight of the spunbonded non-woven fabric [g / m 2 ].
[0104]
(3)
　Transition from maximum elongation [%] and maximum strength [N / 50 mm] spunbonded non-woven fabric to JIS L 1906 6.12.1 [A method] (JIS L 1913: 2010, ISO 9073-3: 1989). The flow direction (MD) is in a constant temperature room with a temperature of 20 ± 2 ° C and a humidity of 65 ± 2% specified in JIS Z 8703 (corresponding to ISO 554: 1976, standard state of the test site). Five test pieces of 25 cm and 5 cm in the lateral direction (CD) were collected. The obtained test piece was subjected to a tensile test using a tensile tester (Instron Japan Company Limited, Instron 5564 type) under the conditions of a chuck distance of 100 mm and a tensile speed of 300 mm / min. The tensile load was measured for 5 test pieces, and the average value of their maximum values ​​was taken as the maximum strength.
　Further, the elongation at the maximum strength was defined as the maximum elongation.
[0105]
(4) Evaluation of
Heat Sealability [Heat Sealing Method]
　Ten test pieces having a flow direction (MD) of 100 mm and a lateral direction (CD) of 100 mm were collected from the spunbonded non-woven fabric. Next, two of these test pieces are overlapped so that the MD directions are the same, and heat seal is performed under the following conditions using a heat seal tester (product name: heat seal tester) manufactured by Tester Sangyo Co., Ltd. rice field.
　Seal bar width: 10.0 mm
　Seal pressure: 2.0 kg / cm 2
　Seal time: 1.0 second
　Seal temperature: Set the upper bar and lower bar to the same temperature (145 ° C)
　Seal direction: Vertical to MD
[0106]
[Confirmation of heat sealability] Using a
　constant velocity tensile tester (manufactured by Toyo Seiki Co., Ltd., product name: Strograph), perform a tensile peel test of a test piece heat-sealed under the above conditions under the following conditions. In each of the five sheets, the presence or absence of peeling was confirmed, and the case where there was no peeling in all five sheets was evaluated as "heat-sealable".
　Specimen shape: Width 20 mm, length 50 mm
　Tensile speed: 30 mm / min
　Atmospheric temperature at the time of measurement: 23 ° C
[0107]
(5) Residual embossing rate [%]
　One test piece having a flow direction (MD) of 250 mm and a lateral direction (CD) of 200 mm was collected from the spunbonded non-woven fabric. The obtained test piece is inserted so that the roll rotation direction of the gear stretching device (in other words, the gear processing machine) as shown in FIG. 3 and the CD direction of the test piece coincide with each other, and the MD direction (that is, the flow of the non-woven fabric) A spunbonded nonwoven fabric gear-stretched in the direction) was obtained. The gear rolls mounted on the gear processing machine each have a diameter of 200 mm and a gear pitch of 2.5 mm, and the meshing depth of both rolls is adjusted to 5.5 mm.
　The embossed portion of the gear-stretched spunbonded non-woven fabric was morphologically observed using a scanning electron microscope (SEM :: Scanning Electron Microscope), and the residual rate of embossing after the gear-stretched was evaluated. The higher the embossing residual rate, the better the tactile sensation. The embossing residual rate was calculated using the following formula.
　Residual embossing = (number of unbroken embossed / number of observed embossed) x 100
　By observing the embossed part of the spunbonded non-woven fabric with the gear stretched, perforation at the embossed part, desorption of fibers, and embossing The embossed part where neither the part nor the fiber breakage at the boundary was confirmed was defined as "unbroken embossed". "Number of unbroken embosses" means the number of unbroken embosses present within the observation range. The "observed number of embosses" means the number of embosses existing in the observation range.
　The residual rate of the embossed fabric formed by the stretching process using the gear processing machine is good, and the fiber breakage of the spunbonded non-woven fabric at the embossed portion and its boundary and the tearing of the non-woven fabric due to the fiber breakage do not occur during the drawing process. Therefore, it can be confirmed that the spunbonded non-woven fabric has good stretch processing suitability.
　As the scanning electron microscope, an S-3500N scanning electron microscope manufactured by Hitachi, Ltd. was used, and the observation magnification was set to 100 times.
[0108]
(6) Flexibility evaluation With
　respect to the spunbonded non-woven fabric, the tactile sensation (touch) when directly touched by hand was sensory evaluated, and the evaluation was made based on the following criteria. The sensory evaluation was performed by 10 monitors, and the evaluation result with the most responses was adopted.
　If there were multiple evaluation results with the most responses, the one with the better result was adopted. 　-Evaluation
criteria-
A: Very good touch and excellent flexibility
　B: Good touch and excellent flexibility compared to the C evaluation below.
　C: It was hard to the touch and inferior in flexibility.
[0109]
[Example 1]

- mixing step
　- MFR (ASTM D 1238, 230 ° C., load 2160 g) 5 g / 10 min, density 0.95 g / cm 3 , and high-density polyethylene 7 a melting point of 134 ° C. 72.7 parts by mass of propylene homopolymer with MFR (ASTM D 1238 , 230 ° C., load 2160 g) 60 g / 10 minutes, density 0.91 g / cm 3 , and melting point 160 ° C., and MFR (ASTM D 1238) , 230 ° C., load 2160 g) 60 g / 10 min, density 0.91 g / cm 3 , and propylene random copolymer at melting point 142 ° C. (polymer of propylene and ethylene, polymerization molar ratio 97: 3, polymer (polymer) I)) 20 parts by mass and 0.3% by mass of erucic acid amide were mixed to obtain a composition.
[0110]
-Nonwoven fabric forming step-
　The composition obtained in the above mixing step was melt-spun using a spunbonded nonwoven fabric manufacturing apparatus (hereinafter, also referred to as "BC") equipped with the two extruders shown in FIG. .. In this spunbond manufacturing apparatus, an extruder 1 (also referred to as "extruder A") and an extruder 1'(also referred to as "extruder B") for extruding raw materials and the extruded raw materials are spun into fibers 3. A collector device including a spinneret 2 and a collecting surface 6 that collects stretched fibers to form a non-woven fabric 8, a bonding unit 9 that heat-seals at least a part of the non-woven fabric 8, and a non-woven fabric 8 after heat-sealing. A winder 10 for winding a non-woven fabric is provided. The collector device includes a suction unit 7 for efficiently collecting fibers by suction under the surface for collecting fibers (collection surface 6). In this spunbonded non-woven fabric manufacturing apparatus, the fibers 3 obtained by the spinneret 2 are cooled by the quench air 4 (air) in the cooling chamber 5.
　Specifically, a spunbonded non-woven fabric manufacturing apparatus (apparatus used for the closed spunbond method) having a spun cap 2 having a number of holes of 5776 holes / m by melting using an extruder 1 having a diameter of 175 mmφ and an extruder 1'with a diameter of 150 mmφ. , The length in the direction perpendicular to the flow direction of the machine on the collection surface 6: 4273 mm), the melting temperature and the die temperature of the composition are both 240 ° C., the cooling air temperature is 20 ° C., and the stretching air air volume is 23655 m 3 Under the condition of / hour, melt spinning was performed by a closed spunbond method. Further, at this time, the amount of the resin composition extruded from the extruder 1 and the extruder 1'was set to be 60:40 on a mass basis.
　The spun fibers 3 are deposited on the collection surface 6 and heat-pressurized with an embossing roll (embossed area ratio (heat crimping ratio) 18%, embossing temperature 125 ° C. or higher and 130 ° C. or lower) to obtain a total basis weight. 18.0 g / m The spunbonded non-woven fabric 8 which is No. 2 was produced.
[0111]
　The obtained spunbonded non-woven fabric of Example 1 was evaluated by the above-mentioned evaluation method.
　The results are shown in Table 1 below.
[0112]
[Example 2]

　The same operation as in Example 1 is performed except that the amount of the resin composition extruded from the extruder 1 and the extruder 1'is set to 70:30 on a mass basis. rice field.
[0113]
　The obtained spunbonded nonwoven fabric of Example 2 was evaluated by the above-mentioned evaluation method.
　The results are shown in Table 1 below.
　Further, FIG. 1A shows an image when the cross section of the fiber in the spunbonded nonwoven fabric obtained in Example 2 is observed with a transmission electron microscope.
[0114]
[Example 3]

　The same operation as in Example 1 is performed except that the amount of the resin composition extruded from the extruder 1 and the extruder 1'is set to 80:20 on a mass basis. rice field.
[0115]
　The obtained spunbonded non-woven fabric of Example 3 was evaluated by the above-mentioned evaluation method.
　The results are shown in Table 1 below.
　Further, FIG. 1B shows an image when the cross section of the fiber in the spunbonded nonwoven fabric obtained in Example 3 is observed with a transmission electron microscope.
[0116]
[Comparative Example 1]

　The composition obtained in the above mixing step is replaced with one spunbonded non-woven fabric manufacturing apparatus (not shown) provided with the two extruders shown in FIG. The same operation as in Example 1 was performed except that melt spinning was performed using a spunbonded nonwoven fabric manufacturing apparatus equipped with an extruder (hereinafter, also referred to as “MC”).
[0117]
　The obtained spunbonded non-woven fabric of Comparative Example 1 was evaluated by the above-mentioned evaluation method.
　The results are shown in Table 1 below.
　Further, FIG. 1C shows an image when the cross section of the fiber in the spunbonded nonwoven fabric obtained in Comparative Example 1 is observed with a transmission electron microscope.
[0118]
[table 1]

[0119]
　From the results in Table 1, it can be seen that the spunbonded nonwoven fabric of the present embodiment obtained in Examples is superior in extensibility as compared with Comparative Examples.
[0120]
　Further, as shown in Table 1 above, the spunbonded non-woven fabrics of the examples are excellent in stretchability, heat sealability is good, and the embossing residual rate is good, so that they are excellent in stretchability. You can see that. Further, all of the spunbonded non-woven fabrics of the examples were excellent in flexibility.
　From these evaluation results, it can be seen that the spunbonded nonwoven fabric of the present embodiment is suitable for applications of sanitary materials that require extensibility, flexibility, and processability.
[0121]
　The disclosure of Japanese Patent Application No. 2019-014680 filed on January 30, 2019 is incorporated herein by reference in its entirety. Also, all documents, patent applications and technical standards described herein are to the same extent as if the individual documents, patent applications and technical standards were specifically and individually stated to be incorporated by reference. , Incorporated by reference herein.

WE CLAIMS

[Claim 1]A melting point of 140 ° C. or more propylene homopolymer, density 0.941 g / cm 3 or more 0.970 g / cm 3 and a polyethylene or less, from the polymer and (II) below are shown the polymer shown below (I)
　Among the island phases in the cross section of the fiber having a sea-island structure and perpendicular to the axial direction of the fiber, which contains a fiber containing at least one polymer selected from the above group , the diameter is 0.12 μm or more. A spunbonded non-woven fabric having an island phase ratio of less than 63 μm of 30% or more on a number basis.
　(I) Random copolymer of propylene and at least one selected from ethylene and α-olefin having 4 or more and 20 or less carbon atoms
　(II) A melting point of less than 120 ° C. satisfying the following (a) to (f). Propylene copolymer
(a) [mmmm] = 20 mol% or more and 60 mol% or less
(b) [rrrr] / (1- [mmmm])
≤0.1 (c) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] 2 ≦ 2.0
(e) Weight average molecular weight (Mw) = 10,000 or more and 200,000 or less
(f) Molecular weight distribution (Mw / Mn) <4
( In a) to (d), [mmmm] is the mesopentad fraction, [rrrr] is the lasemipentad fraction, and [polymer] is the lasemimesola semimesopentad fraction, [mm], [ rr] and [mr] are triad fractions, respectively, and Mn is a number average molecular weight.
[Claim 2]
　The spunbonded nonwoven fabric according to claim 1, wherein the proportion of island phases having a diameter of 0.63 μm or more is 10% or less on a number basis.
[Claim 3]
　The spunbonded nonwoven fabric according to claim 1 or 2, wherein the proportion of island phases having a diameter of less than 0.12 μm is 70% or less on a number basis.
[Claim 4]
　The spunbonded nonwoven fabric according to any one of claims 1 to 3, wherein the content of the polyethylene is 1.0% by mass or more and 15.0% by mass or less with respect to the total amount of the fibers.
[Claim 5]
　The content of at least one polymer selected from the group consisting of the polymer shown in (I) and the polymer shown in (II) is 5.0% by mass or more and 30.0% by mass with respect to the total amount of the fibers. % Or less, the spunbonded nonwoven fabric according to any one of claims 1 to 4.
[Claim 6]
　The content of the propylene homopolymer having a melting point of 140 ° C. or higher is 55.0% by mass or more and 90.0% by mass or less based on the total amount of the fibers, according to any one of claims 1 to 5. The spunbonded non-woven fabric described.
[Claim 7]
　When the fiber contains a fatty acid amide having 15 or more and 22 or less carbon atoms and the content of the fatty acid amide having 15 or more and 22 carbon atoms is 0.1% by mass or more and 5.0% by mass or less based on the total amount of the fiber. The spunbonded non-woven fabric according to any one of claims 1 to 6.
[Claim 8]
　The span according to any one of claims 1 to 7, wherein the polymer shown in (I) is a random copolymer containing at least a structural unit derived from propylene and a structural unit derived from ethylene. Bond non-woven fabric.
[Claim 9]
　A sanitary material containing the spunbonded nonwoven fabric according to any one of claims 1 to 8.
[Claim 10]
　A melting point of 140 ° C. or more propylene homopolymer, density 0.941 g / cm 3 or more 0.970 g / cm 3 and a polyethylene or less, from the polymer and (II) below are shown the polymer shown below (I) A composition containing at least one polymer selected from the above group is extruded from the extruder A and the extruder B in an amount of 85:15 to 55:45 on a mass basis (extruder A: A method for producing a spunbonded non-woven fabric, which comprises extruding so as to become an extruder B).
　(I) Random copolymer of propylene and at least one selected from ethylene and α-olefin having 4 or more and 20 or less carbon atoms
　(II) A melting point of less than 120 ° C. satisfying the following (a) to (f). Propylene copolymer
(a) [mmmm] = 20 mol% or more and 60 mol% or less
(b) [rrrr] / (1- [mmmm])
≤0.1 (c) [rmrm]> 2.5 mol%
(D) [mm] × [rr] / [mr] 2 ≦ 2.0
(e) Weight average molecular weight (Mw) = 10,000 or more and 200,000 or less
(f) Molecular weight distribution (Mw / Mn) <4
( In a) to (d), [mmmm] is the mesopentad fraction, [rrrr] is the lasemipentad fraction, and [polymer] is the lasemimesola semimesopentad fraction, [mm], [ rr] and [mr] are triad fractions, respectively, and Mn is a number average molecular weight.
[Claim 11]
　The method for producing a spunbonded nonwoven fabric according to claim 10, wherein the diameter A of the extruder A is larger than the diameter B of the extruder B.