Long-fiber nonwoven fabric, method for manufacturing same, laminate, and sanitary material

Abstract

Provided is a long-fiber nonwoven fabric having high elongation, excellent stretchability after drawing, and suitable touch feeling.　This long-fiber nonwoven fabric contains crimped fibers FA, wherein the long-fiber nonwoven fabric has a fused part and a non-fused part, and the ratio (Ra / Tb) of the surface roughness Ra of the fused part to the thickness Tb of the fused part is 0.20-0.80, and the elongation recovery rate of the long-fiber nonwoven fabric is 50-99%.

Description

Long fiber nonwoven fabric, method for manufacturing the same, and laminates, sanitary materials

[0001] This invention relates to spunbond nonwoven fabrics.

[0002] In recent years, there has been a growing demand for improved comfort in sanitary materials such as disposable diapers and sanitary napkins. In particular, for materials that cover the waist and buttocks, it is desirable for them to conform to the contours of the body, so the nonwoven fabric materials used must have elasticity (the ability to stretch and shrink well) and a superior feel.

[0003] Traditionally, components made by bonding elastic threads, such as spandex (a polyurethane elastic fiber), to a loose, non-stretchable nonwoven fabric have been widely used in such areas. However, in such components, the loose, non-stretchable nonwoven fabric covers the elastic threads, which have a sticky feel (hereinafter also referred to as "rubber touch"). The folds created by the sagging of the non-stretchable nonwoven fabric create unevenness in the tightening force of the elastic threads, resulting in a poor fit.

[0004] To address this problem, for example, Patent Document 1 proposes a method for manufacturing an elastic nonwoven fabric, comprising the steps of forming a substantially inelastic first inelastic fiber web made of continuous fibers by the spunbond method, directly depositing elastic fibers made of continuous fibers spun by the spunbond method onto the first inelastic fiber web to form a second elastic fiber web, forming a substantially inelastic third inelastic fiber web made of continuous fibers onto the second elastic fiber web by the spunbond method to obtain a web laminate, fully bonding the webs together by an air-through type hot air treatment to obtain a fiber sheet, stretching the fiber sheet, and then easing the stretch to exhibit elasticity. Furthermore, Patent Document 2 proposes a stretchable nonwoven fabric obtained by partially fusing a web made of mixed fibers, which include fiber A made of a specific thermoplastic polyurethane elastomer and fiber B made of a thermoplastic polymer other than thermoplastic polyurethane elastomer, and then stretching it.

[0005] Japanese Patent Publication No. 4969158, Japanese Unexamined Patent Publication No. 2004-244791

[0006] The technology described in Patent Document 1 obtains an elastic nonwoven fabric by covering the rubber-touch elastic fiber layer with a non-elastic fiber layer and then easing the tension of the non-elastic fiber layer through stretching. However, in Patent Document 1, the intersections of the constituent fibers are bonded by heat fusion across the entire surface of the elastic fiber layer and non-elastic fiber layer constituting the stretchable nonwoven fabric, resulting in poor stretchability before stretching. The stretchability of a nonwoven fabric is its ability to stretch uniformly without tearing or openings, and greatly affects the wearing comfort when applied to sanitary materials. In Patent Document 1, the distribution of heat fusion points between fibers is uneven due to the random orientation and distance of the fibers, and the stress during stretching is unevenly distributed, making it prone to openings, thus resulting in poor stretchability. In this way, a nonwoven fabric that is unevenly stretched will have uneven stretchability in different areas, resulting in a poor fit when used as a sanitary material. Furthermore, after stretching, the fibers in the non-elastic fiber layer become significantly loose, resulting in a material that is excessively thick for use as a sanitary material.

[0007] On the other hand, in the technology described in Patent Document 2, a web containing fibers made of a polymer including a thermoplastic polyurethane elastomer and fibers made of a thermoplastic polymer is partially fused together by embossing or other means, which makes it possible to prevent uneven stress distribution during subsequent stretching and to enable uniform stretching. However, during stretching, fibers B tend to become taut between the fused parts, resulting in poor stretchability. Furthermore, even if stretched at a high stretching ratio by force, the fibers at the fused parts are compressed into a film-like state, making them difficult to stretch and deform. This can lead to uneven stress distribution in the fibers around the fused parts, causing pores to form or making uniform stretching difficult. Moreover, after stretching, the fibers made of the thermoplastic polymer sag considerably, resulting in a thickness that is excessive for use as a sanitary material.

[0008] In view of the above circumstances, the objective was to provide a long-fiber nonwoven fabric that has high elongation and excellent elasticity, while also allowing for suitable control of the thickness of the nonwoven fabric and possessing a superior tactile feel for use as a sanitary material.

[0009] As a result of diligent studies to achieve the above objectives, the following long-fiber nonwoven fabrics were developed: (1) A long-fiber nonwoven fabric containing crimped fiber FA, wherein the long-fiber nonwoven fabric has fused portions and non-fused portions, the ratio of the surface roughness Ra of the fused portion to the thickness Tb of the fused portion (Ra / Tb) is 0.20 or more and 0.80 or less, and the elongation recovery rate of the long-fiber nonwoven fabric is 50% or more and 99% or less. (2) A long-fiber nonwoven fabric containing fiber FA', wherein the long-fiber nonwoven fabric has fused portions and non-fused portions, the ratio of the surface roughness Ra of the fused portion to the thickness Tb of the fused portion (Ra / Tb) is 0.20 or more and 0.80 or less, the elongation recovery rate of the long-fiber nonwoven fabric is 50% or more and 99% or less, and the fiber FA' satisfies the following (a) and (b). (a) Having a core-sheath composite cross section; (b) The difference (OC-OS) between the molecular orientation parameter OC in the fiber axis direction in the core component and the molecular orientation parameter OS in the fiber axis direction in the sheath component is 1.5 or more and 5.0 or less. (3) The long fiber nonwoven fabric according to (1) or (2), comprising: crimped fiber FA mainly composed of thermoplastic resin A or fiber FA' mainly composed of thermoplastic resin A'; and fiber FB mainly composed of thermoplastic resin B different from thermoplastic resin A or thermoplastic resin A'. (4) The long fiber nonwoven fabric according to (3), wherein the ratio of crimped fiber FA or fiber FA' is 50% or more on at least one surface of the long fiber nonwoven fabric. (5) The long-fiber nonwoven fabric according to (3) or (4), wherein the modulus of elasticity EB of the fiber FB is 0.005 times or more and 0.400 times or less of the modulus of elasticity EA of the crimped fiber FA or the modulus of elasticity EA' of the fiber FA'. (6) The long-fiber nonwoven fabric according to any one of (3) to (5), wherein 80.0% by mass or more and 100.0% by mass of the thermoplastic resin B is one or more selected from the group consisting of polyolefin elastomers, styrene elastomers, polyurethane elastomers, amide elastomers, and polyester elastomers. (7) The apparent density of the long-fiber nonwoven fabric after 100% stretching is 0.020 g / cm³. ３ 0.200g / cm or more ３The following is a long-fiber nonwoven fabric according to any one of (1) to (6) above. (8) A laminate having a long-fiber nonwoven fabric according to any one of (1) to (7) above and a layer different from the long-fiber nonwoven fabric. (9) A sanitary material comprising at least a portion of the long-fiber nonwoven fabric according to any one of (1) to (7) above. (10) A method for producing a long-fiber nonwoven fabric according to any one of (1), (6), or (7) above, comprising the steps of: extruding a polymer stream containing thermoplastic resin A and thermoplastic resin B different from thermoplastic resin A from a spinneret to form a web; and pressurizing the web with a roll having a surface temperature of TmB - 50°C or more and TmB + 70°C or less, where TmB (°C) is the melting point of thermoplastic resin B, to form a fused sheet having fused portions and non-fused portions. (11) A method for producing a long fiber nonwoven fabric according to any one of (3) to (7), comprising: forming a web A with crimped fibers FA mainly composed of thermoplastic resin A; forming a web B with fibers FB mainly composed of thermoplastic resin B different from thermoplastic resin A; producing a laminated web by laminating the web A and the web B; and pressurizing the laminated web with a roll having a surface temperature of TmB-50°C or more and TmB+70°C or less, where TmB (°C) is the melting point of thermoplastic resin B, to form a fused sheet having fused portions and non-fused portions. (12) A method for producing a long fiber nonwoven fabric according to any one of (3) to (7), comprising the steps of: forming a web A' containing fibers FA' mainly composed of thermoplastic resin A'; forming a web B with fibers FB mainly composed of thermoplastic resin B different from the thermoplastic resin A'; producing a laminated web by laminating the web A' and the web B; and forming a fused sheet having fused portions and unfused portions by pressurizing the laminated web with a roll having a surface temperature of TmB-50°C or more and TmB+70°C or less, where TmB (°C) is the melting point of the thermoplastic resin B.

[0010] The long-fiber nonwoven fabric of the present invention uses fibers having crimp or fibers with a core-sheath type composite cross section having a specific orientation, and further controls the shape of the fused portion of the nonwoven fabric, resulting in a long-fiber nonwoven fabric that is highly extensible and can be uniformly stretched. Moreover, after stretching, it has excellent elasticity and a good feel, making it suitable for use as a nonwoven fabric for hygiene products.

[0011] Figure 1 is a schematic side view of the crimped fiber FA according to the present invention, as seen when observed with a scanning electron microscope (SEM). Figure 2 is a cross-sectional scanning electron microscope (SEM) image of an example of a fused portion of a conventionally known long-fiber nonwoven fabric. Figure 3 is a surface scanning electron microscope (SEM) image of a fused portion in a conventionally known long-fiber nonwoven fabric. Figure 4 is a surface scanning electron microscope (SEM) image of an example of a fused portion of a long-fiber nonwoven fabric according to the present invention.

[0012] The long-fiber nonwoven fabric of the present invention is a long-fiber nonwoven fabric containing crimped fibers FA, wherein the long-fiber nonwoven fabric has a fused portion and a non-fused portion, the ratio of the surface roughness Ra of the fused portion to the thickness Tb of the fused portion (Ra / Tb) is 0.20 or more and 0.80 or less, and the elongation recovery rate of the long-fiber nonwoven fabric is 50% or more and 99% or less.

[0013] Furthermore, the long-fiber nonwoven fabric of the present invention is a long-fiber nonwoven fabric containing fiber FA', wherein the long-fiber nonwoven fabric has a fused portion and a non-fused portion, the ratio of the surface roughness Ra of the fused portion to the thickness Tb of the fused portion (Ra / Tb) is 0.20 or more and 0.80 or less, the elongation recovery rate of the long-fiber nonwoven fabric is 50% or more and 99% or less, and the fiber FA' satisfies the following (a) and (b): (a) It has a core-sheath composite cross section; (b) The difference (OC-OS) between the molecular orientation parameter OC in the fiber axis direction in the core component and the molecular orientation parameter OS in the fiber axis direction in the sheath component is 1.5 or more and 5.0 or less.

[0014] The components are described in detail below, but the present invention is not limited to the scope described below, unless it exceeds the gist of the invention.

[0015] [Crimped Fiber FA, Thermoplastic Resin A] The long fiber nonwoven fabric of the present invention contains crimped fiber FA. The crimped fiber FA is preferable because it is mainly composed of thermoplastic resin A, resulting in a long fiber nonwoven fabric with excellent elongation properties. Here, "crimped fiber mainly composed of thermoplastic resin A" means that 50% by mass or more of the fiber is thermoplastic resin A.

[0016] The thermoplastic resin A preferably used in the crimped fiber FA of the present invention may be any conventionally known thermoplastic resin, for example, aromatic polyester polymers and copolymers such as "polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate," aliphatic polyester polymers and copolymers such as "polylactic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvalate copolymer, polycaprolactone," and polyamide 6, poly These include aliphatic polyamide polymers and copolymers such as "Amid 66, Polyamide 610, Polyamide 10, Polyamide 12, Polyamide 6-12," polyolefin polymers and copolymers such as "Polypropylene, Polyethylene, Polybutene, Polymethylpentene," water-insoluble ethylene-vinyl alcohol copolymer polymers containing 25 mol% to 70 mol% ethylene units, polystyrene-based, polydiene-based, chlorine-based, polyolefin-based, polyester-based, polyurethane-based, polyamide-based, and fluorine-based elastomer polymers, and can be selected and used from among these.

[0017] In particular, aromatic polyester polymers and their copolymers, aliphatic polyester polymers and their copolymers, aliphatic polyamide polymers and their copolymers, polyolefin polymers and their copolymers, and ethylene-vinyl alcohol copolymer polymers are preferred because they have a moderate modulus of elasticity, resulting in nonwoven fabrics with less uneven stress distribution and high elongation.

[0018] The crimped fiber FA of the present invention preferably has the thermoplastic resin A as its main component, but the thermoplastic resin A may be one type of thermoplastic resin or a plurality of thermoplastic resins.

[0019] Furthermore, the polymer may contain various additives such as inorganic substances like titanium dioxide, silica, and barium oxide, carbon black, colorants such as dyes and pigments, flame retardants, fluorescent whitening agents, antioxidants, or ultraviolet absorbers.

[0020] In particular, since reducing frictional interactions between fibers results in a highly elongated long-fiber nonwoven fabric, it is preferable that the crimped fiber FA contains a fatty acid amide compound with 15 to 50 carbon atoms. Note that the carbon number refers to the number of carbon atoms contained in the molecule, including the number of carbon atoms contained in amide groups, etc.

[0021] The aforementioned fatty acid amide compounds with 15 to 50 carbon atoms include palmitic acid amide, palmitoleic acid amide, stearic acid amide, oleic acid amide, elaidic acid amide, vaccenic acid amide, linoleic acid amide, linolenic acid amide, pinolenic acid amide, eleostearic acid amide, stearidonic acid amide, bosopentaenoic acid amide, arachidinic acid amide, gadrenic acid amide, eicosenoic acid amide, eicosadienoic acid amide, meadic acid amide, eicosatrienoic acid amide, arachidonic acid amide, eicosatetraenoic acid amide, eicosapentaenoic acid amide, henicosyl acid amide, behenic acid amide, erucic acid amide, docosadienoic acid amide, adrenaline amide, osbondic acid amide, sardine acid amide, docosahexaenoic acid amide, Examples include lignoceramide, nervonamide, tetracosapentaenoamide, hernamide, cerotinamide, montanaamide, melisinamide, ethylenebiscaprateamide, ethylenebislaurateamide, methylenebislaurateamide, ethylenebisstearateamide, ethylenebisoleamide, ethylenebishydroxystearamide, ethylenebisbehenamide, ethylenebiserucamide, hexamethylenebisstearateamide, hexamethylenebisbehenamide, hexamethylenehydroxystearamide, distearyladipamide, distearylsebacinamide, and hexamethylenebisoleamide, and multiple combinations of these can be used. In particular, the use of stearamide and erucamide as fatty acid amide compounds is preferable because it allows for appropriate control of the friction of the crimped fibers FA, resulting in a long-fiber nonwoven fabric with excellent elongation properties.

[0022] The fatty acid amide compound preferably has 15 or more carbon atoms, more preferably 23 or more, and even more preferably 30 or more, which enhances the effect of reducing frictional interactions between fibers and results in a long-fiber nonwoven fabric with excellent stretchability. On the other hand, the fatty acid amide compound preferably has 50 or fewer carbon atoms, more preferably 45 or fewer, and even more preferably 42 or fewer, which allows the fatty acid amide compound to precipitate appropriately on the fiber surface, resulting in a long-fiber nonwoven fabric with excellent flexibility. Furthermore, in order to achieve both reduced interaction between fibers and a desirable tactile feel for the long-fiber nonwoven fabric, the content of the fatty acid amide compound is preferably 0.1% to 5.0% of the mass of the crimped fiber FA.

[0023] The long-fiber nonwoven fabric of the present invention contains crimped fibers FA. Here, "crimped fibers FA" refers to fibers whose radius of curvature, measured and calculated as follows, is 1500 μm or less. <Method for measuring the radius of curvature> (i) One 2 cm x 2 cm test piece is randomly cut from the long-fiber nonwoven fabric. (ii) In the extracted test piece, the areas where the fibers are not fused together are finely cut with scissors to produce small pieces of fibers constituting the long-fiber nonwoven fabric (pieces approximately 0.5 mm square). (iii) The small pieces of fibers produced in (ii) above are observed with a scanning electron microscope (SEM, for example, "VHX-6000" manufactured by Keyence Corporation), and fibers that satisfy the following two conditions are searched for, and images are taken at a magnification of 400x or more. Condition - Not overlapping with other fibers and can be observed independently. Condition - The length of the fiber is 200 μm or more and 1000 μm or less. (iv) In the captured image, curved fibers are observed as shown in Figure 1. For the captured image, the radius of curvature of the inner contour of the curved shape (1-A in Figure 1) and the outer contour of the curved shape (1-B in Figure 1) are measured in μm, and the arithmetic mean of these is calculated. (v) The arithmetic mean of the results obtained by performing the above steps (ii) to (iv) on 50 different fibers is calculated, and the value obtained by rounding to the first decimal place is defined as the "radius of curvature". If the radius of curvature is 1500 μm or less, the fiber is identified as a crimped fiber FA.

[0024] As described above, the long fiber nonwoven fabric of the present invention contains the crimped fiber FA. By containing the crimped fiber FA, when the long fiber nonwoven fabric is stretched, the crimped fiber FA is less likely to be tensioned, so that a long fiber nonwoven fabric with high extensibility is obtained. Since the smaller the value of the radius of curvature, the more the crimped fiber FA is bent, the radius of curvature is preferably 1000 μm or less, more preferably 900 μm or less, and even more preferably 800 μm or less, resulting in a long fiber nonwoven fabric with even better extensibility. Also, since the interaction between the crimped fibers FA is preferably controlled by the radius of curvature being preferably 100 μm or more, a long fiber nonwoven fabric with better extensibility is obtained.

[0025] The crimped fiber FA contained in the long fiber nonwoven fabric of the present invention may be a single-component fiber mainly composed of the thermoplastic resin A, or may be a composite fiber composed of a plurality of the thermoplastic resins A. However, from the viewpoint of preferably controlling the radius of curvature, it is preferable that the crimped fiber FA is a composite fiber, and particularly preferably a side-by-side type composite fiber or an eccentric core-sheath type composite fiber. When the crimped fiber FA is a side-by-side type composite fiber and an eccentric core-sheath type composite fiber, in order to make the radius of curvature within the above range, for example, means such as adjusting the composition of the polymer used for the thermoplastic resin A, viscosity, molecular weight distribution, fiber diameter, cross-sectional shape, spinning speed, and cooling conditions during spinning can be mentioned.

[0026] The average single fiber diameter of the crimped fiber FA contained in the long fiber nonwoven fabric of the present invention is preferably 5.0 μm or more and 30.0 μm or less, resulting in a long fiber nonwoven fabric with excellent extensibility. Since the average single fiber diameter is preferably 5.0 μm or more, more preferably 8.0 μm or more, and even more preferably 10.0 μm or more, the interaction due to friction between the fibers can be preferably controlled. Also, since the average single fiber diameter of the crimped fiber FA is preferably 30.0 μm or less, more preferably 25.0 μm or less, and even more preferably 20.0 μm or less, the crimped fiber FA can be uniformly dispersed in the nonwoven fabric and the uneven distribution of stress can be suppressed, resulting in a long fiber nonwoven fabric with even better extensibility.

[0027] Incidentally, the average single fiber diameter of the crimped fiber FA is measured and calculated by the following method. (i) An image of the cross-section of the crimped fiber FA is taken with a scanning electron microscope (SEM, such as "VHX-6000" manufactured by Keyence Corporation, Ltd.) at a magnification at which one single fiber can be observed. (ii) Using the image of the photographed fiber cross-section, the area Af (μm ２ ) formed by the cross-sectional contour of the single fiber is measured, and the diameter of a perfect circle having the same area as this area Af is calculated, and this is taken as the single fiber diameter (μm) of this fiber. (iii) The single fiber diameters of 20 single fibers arbitrarily extracted in the procedure of (ii) above are measured, and their arithmetic mean value (μm) is obtained, and the value obtained by rounding off the second decimal place is taken as the average single fiber diameter of the crimped fiber FA.

[0028] [Fiber FA', Thermoplastic Resin A'] The long fiber nonwoven fabric of the present invention contains a fiber FA' that satisfies the following (a) and (b). Since the fiber FA' is easily deformed with a small force when the long fiber nonwoven fabric of the present invention is stretched, a long fiber nonwoven fabric with high extensibility is obtained. (a) It has a core-sheath type composite cross-section. (b) The difference (OC - OS) between the molecular orientation parameter OC in the fiber axis direction in the core component and the molecular orientation parameter OS in the fiber axis direction in the sheath component is 1.5 or more and 5.0 or less.

[0029] Here, the "core-sheath type composite cross-section" means a cross-section composed of a sheath component that covers 90% or more of the outer shape length of the single fiber when observing the cross-section of the single fiber, and a core component of a thermoplastic resin having different properties from the sheath component. The above "having different properties" means that the type of thermoplastic resin, molecular weight, molecular weight distribution, type of additive, etc. are different.

[0030] The fiber FA' contained in the long fiber nonwoven fabric of the present invention can achieve both appropriate elongation and strength by having a core-sheath type composite cross-section, and a long fiber nonwoven fabric excellent in extensibility can be obtained.

[0031] The fibers FA' included in the long-fiber nonwoven fabric of the present invention may be concentric core-sheath composite cross-sections where the center of gravity of the core component and the center of gravity of the single fiber coincide when the cross-section of the single fiber is observed, or eccentric core-sheath composite cross-sections where the center of gravity of the core component and the center of gravity of the single fiber do not coincide. It is preferable that the core component is not exposed on the fiber surface, as this results in good adhesion between the core component and the sheath component, and thus a long-fiber nonwoven fabric with a good tactile feel.

[0032] The fibers FA' contained in the long-fiber nonwoven fabric of the present invention have a difference (OC-OS) between the molecular orientation parameter OC in the fiber axial direction in the core component and the molecular orientation parameter OS in the fiber axial direction in the sheath component, which is 1.5 or more and 5.0 or less. When OC-OS is 1.8 or more, preferably 2.0 or more, the polymer-oriented core component ensures fiber strength, while the low-molecular-weight-oriented sheath component facilitates fiber elongation, resulting in a long-fiber nonwoven fabric with excellent elongation and tactile properties. Furthermore, when OC-OS is 5.0 or less, preferably 4.0 or less, the molecular orientation of the core component is controlled, the elongation load of the fibers FA' can be reduced, and a long-fiber nonwoven fabric with excellent elongation properties can be obtained.

[0033] The molecular orientation parameter OC in the fiber axis direction in the core component, the molecular orientation parameter OS in the fiber axis direction in the sheath component, and their difference OC-OS, as used herein, are measured and calculated as follows. <Method for measuring molecular orientation parameters> (i) Identify the polymer constituting the fiber FA' in the long fiber nonwoven fabric using the following procedure (i-1) to (i-6). (i-1) Cut the non-fused portion of the long fiber nonwoven fabric into small pieces and collect single fibers of 2 mm or more. (i-2) Identify the polymer of the single fibers using a micro-Raman spectrometer (for example, the "inVia" Raman spectrometer manufactured by RENISHAW). (i-3) Using the single fiber sample used for polymer identification in procedure (i-2), the elastic modulus is measured in units of MPa using an atomic force microscope (AFM) capable of measuring the elastic modulus with a probe (cantilever) (for example, "Nano-TA2" from Anasys Instruments). (i-4) For 10 single fibers identified as the same polymer in procedure (i-2), the measurement in (i-3) is repeated, the arithmetic mean of the obtained elastic moduli is calculated, and the value is rounded to the first decimal place. (i-5) If there are multiple single fibers with different polymers in procedure (i-2), the measurements in procedures (i-2) to (i-4) are repeated for all polymer types to measure the elastic modulus of each. (i-6) Among the measured single fibers, the polymer constituting the single fiber with the highest elastic modulus is identified as the polymer constituting the fiber FA' in the long fiber nonwoven fabric.

[0034] (ii) The OC and OS of fiber FA' are measured using the following procedures (iii-1) to (iii-4). (iii-1) For the fiber FA' identified in procedure (i-6) above, the fiber is cut with a razor at a cutting angle of approximately 4° with respect to the fiber axis to expose the fiber longitudinal section. Then, it is set in a micro-Raman spectrometer (for example, a Raman spectrometer "inVia" manufactured by RENISHAW Corporation) and a laser is irradiated onto the fiber longitudinal section from a direction perpendicular to the fiber axis to perform a micro-Raman measurement. (ii-2) The measurement is performed under conditions in which the polarization direction is parallel to the fiber axis to obtain polarized Raman spectra of the core component and sheath component. (ii-3) 810 cm² is attributed to the coupling mode of CH2 bending vibration and C-C stretching vibration. －１Let the Raman band intensity in the vicinity be I ８１０ and let the Raman band intensity at 840 cm －１ attributed to the CH2 bending vibration mode be I ８４０ . Calculate the molecular orientation parameter using the following formula. Molecular orientation parameter = I ８１０ / I ８４０ (ii-4) Perform the measurements of the procedures (ii-1) to (ii-3) on three different single fibers, and round off the second decimal place of the arithmetic mean value of the molecular orientation parameter in the fiber axis direction in the core component to obtain the molecular orientation parameter OC in the fiber axis direction in the core component, and round off the second decimal place of the arithmetic mean value of the molecular orientation parameter in the fiber axis direction in the sheath component to obtain the molecular orientation parameter OS in the fiber axis direction in the sheath component.

[0035] (iii) Calculate OC - OS from the values of OC and OS measured in the procedure (ii).

[0036] In the fiber FA' contained in the long fiber nonwoven fabric of the present invention, the molecular orientation parameter OC in the fiber axis direction in the core component is preferably 4.5 or more and 7.0 or less, more preferably 5.0 or more and 6.0 or less. From this, the fiber FA' has appropriate rigidity and has strength and elongation, resulting in a long fiber nonwoven fabric excellent in elongation.

[0037] Also, in the fiber FA' contained in the long fiber nonwoven fabric of the present invention, the molecular orientation parameter OS in the fiber axis direction in the sheath component is preferably 2.0 or more and 4.5 or less, more preferably 2.5 or more and 4.0 or less. From this, the fiber FA' has high elongation and can maintain its shape in the process of forming the fusion part described later, resulting in a long fiber nonwoven fabric excellent in elongation.

[0038] In order to make OC - OS of the fiber FA' contained in the long fiber nonwoven fabric of the present invention within the above range, for example, means for adjusting the composition of the polymer used for the thermoplastic resin A', viscosity, molecular weight distribution, fiber diameter, cross-sectional shape, spinning speed, cooling conditions during spinning, etc. can be mentioned.

[0039] In the long-fiber nonwoven fabric of the present invention, it is preferable that the area ratio of the sheath component in the cross-section of the fiber FA' is 50% or more and 90% or less, so that the highly oriented core component does not inhibit the elongation of the fiber FA', resulting in a long-fiber nonwoven fabric with excellent elongation properties. The area ratio of the sheath component in the cross-section referred to here is determined as follows. <Method for measuring the area ratio> (i) Fiber FA' is collected using the method of procedure (i) in the method for measuring molecular orientation parameters described above. (ii) Twenty collected fibers FA' are embedded, and sections are prepared using a microtome so that the cross-section of a single fiber can be observed, and placed on a glass slide. (iii) Images of the sections are taken using a transmission microscope at a magnification that allows the cross-section of a single fiber to be observed. (iv) Using image analysis software (for example, "WinROOF2015" manufactured by Mitani Corporation) to capture the images, the cross-sectional area of ​​the fiber (Af) and the area of ​​the core component (AC) are measured, and the area ratio of the sheath component is calculated using the following formula: (Area ratio of sheath component) = 100 × (Af - AC) / Af (v) The simple numerical average of the results obtained by performing the operation of procedure (iv) above on 20 different fibers FA', and the value rounded to the first decimal place, is the area ratio of the sheath component in the cross-section as referred to in this invention.

[0040] The average single fiber diameter of the fibers FA' contained in the long-fiber nonwoven fabric of the present invention is preferably 5.0 μm or more and 30.0 μm or less, as this results in a long-fiber nonwoven fabric with excellent elongation properties. Preferably, this average single fiber diameter is 5.0 μm or more, more preferably 8.0 μm or more, and even more preferably 10.0 μm or more. This allows for favorable control of frictional interactions between fibers. Furthermore, preferably, the average single fiber diameter of the fibers FA' is 30.0 μm or less, more preferably 25.0 μm or less, and even more preferably 20.0 μm or less. This allows for uniform dispersion of the fibers FA' in the nonwoven fabric, suppressing uneven stress distribution, resulting in a long-fiber nonwoven fabric with even greater elongation properties.

[0041] The fiber FA' contained in the long fiber nonwoven fabric of the present invention is a core-sheath type composite cross-section fiber having a specific orientation, and is preferable because it is mainly composed of thermoplastic resin A', resulting in a long fiber nonwoven fabric with excellent mechanical strength. Here, "a fiber mainly composed of thermoplastic resin A'" means that 50% or more by mass of the fiber is thermoplastic resin A', and refers to the sheath component.

[0042] The thermoplastic resin A' preferably used in the fiber FA' of the present invention may be any conventionally known thermoplastic resin, for example, aromatic polyester polymers and copolymers such as "polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate," aliphatic polyester polymers and copolymers such as "polylactic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvalate copolymer, polycaprolactone," and polyamide 6, poly These include aliphatic polyamide polymers and copolymers such as "Amid 66, Polyamide 610, Polyamide 10, Polyamide 12, Polyamide 6-12," polyolefin polymers and copolymers such as "Polypropylene, Polyethylene, Polybutene, Polymethylpentene," water-insoluble ethylene-vinyl alcohol copolymer polymers containing 25 mol% to 70 mol% ethylene units, polystyrene-based, polydiene-based, chlorine-based, polyolefin-based, polyester-based, polyurethane-based, polyamide-based, and fluorine-based elastomer polymers, and can be selected and used from among these.

[0043] In particular, aromatic polyester polymers and their copolymers, aliphatic polyester polymers and their copolymers, aliphatic polyamide polymers and their copolymers, polyolefin polymers and their copolymers, and ethylene-vinyl alcohol copolymer polymers are preferred because they have a moderate modulus of elasticity, resulting in nonwoven fabrics with less uneven stress distribution and high elongation.

[0044] The fiber FA' of the present invention preferably has the thermoplastic resin A' as its main component, but the thermoplastic resin A' may be one type of thermoplastic resin or a plurality of thermoplastic resins.

[0045] Furthermore, the polymer may contain various additives such as inorganic substances like titanium dioxide, silica, and barium oxide, carbon black, colorants such as dyes and pigments, flame retardants, fluorescent whitening agents, antioxidants, or ultraviolet absorbers.

[0046] In particular, since reducing frictional interactions between fibers results in a highly elongated long-fiber nonwoven fabric, it is preferable that the fiber FA' contains a fatty acid amide compound with 15 to 50 carbon atoms. The carbon number refers to the number of carbon atoms contained in the molecule, including the carbon atoms contained in the amide group, etc.

[0047] The aforementioned fatty acid amide compounds with 15 to 50 carbon atoms include palmitic acid amide, palmitoleic acid amide, stearic acid amide, oleic acid amide, elaidic acid amide, vaccenic acid amide, linoleic acid amide, linolenic acid amide, pinolenic acid amide, eleostearic acid amide, stearidonic acid amide, bosopentaenoic acid amide, arachidinic acid amide, gadrenic acid amide, eicosenoic acid amide, eicosadienoic acid amide, meadic acid amide, eicosatrienoic acid amide, arachidonic acid amide, eicosatetraenoic acid amide, eicosapentaenoic acid amide, henicosyl acid amide, behenic acid amide, erucic acid amide, docosadienoic acid amide, adrenaline amide, osbondic acid amide, sardine acid amide, docosahexaenoic acid amide, Examples include lignoceramide, nervonamide, tetracosapentaenoamide, hernamide, cerotinamide, montanaamide, melisinamide, ethylenebiscaprateamide, ethylenebislaurateamide, methylenebislaurateamide, ethylenebisstearateamide, ethylenebisoleamide, ethylenebishydroxystearamide, ethylenebisbehenamide, ethylenebiserucamide, hexamethylenebisstearateamide, hexamethylenebisbehenamide, hexamethylenehydroxystearamide, distearyladipamide, distearylsebacinamide, and hexamethylenebisoleamide, and multiple combinations of these can be used. In particular, the use of stearamide and erucamide as fatty acid amide compounds is preferable because it allows for appropriate control of the friction of the fiber FA', resulting in a long-fiber nonwoven fabric with excellent elongation.

[0048] The fatty acid amide compound preferably has 15 or more carbon atoms, more preferably 23 or more, and even more preferably 30 or more, which enhances the effect of reducing frictional interactions between fibers and results in a long-fiber nonwoven fabric with excellent stretchability. On the other hand, the fatty acid amide compound preferably has 50 or fewer carbon atoms, more preferably 45 or fewer, and even more preferably 42 or fewer, which allows the fatty acid amide compound to precipitate appropriately on the fiber surface, resulting in a long-fiber nonwoven fabric with excellent flexibility. Furthermore, in order to achieve both a reduction in interaction between fibers and a desirable tactile feel for the long-fiber nonwoven fabric, the content of the fatty acid amide compound is preferably 0.1% to 5.0% of the mass of the fiber FA'.

[0049] [Thermoplastic resin B, fiber FB] The long-fiber nonwoven fabric of the present invention preferably contains fiber FB which is mainly composed of thermoplastic resin B, which is different from the thermoplastic resin A. Having such a long-fiber nonwoven fabric results in a long-fiber nonwoven fabric that is stretchable in addition to being extensible. "A fiber which is mainly composed of thermoplastic resin B" means that 50% by mass or more of the fiber is thermoplastic resin B.

[0050] The thermoplastic resin B is different from thermoplastic resin A. Here, "a resin different from thermoplastic resin A" means a resin of a different type from thermoplastic resin A (for example, if thermoplastic resin A is polyethylene terephthalate, thermoplastic resin B may be a polyester elastomer or copolymerized polyethylene terephthalate, etc.), and resins of the same type but with different molecular weight or viscosity are not considered "a resin different from thermoplastic resin A". The thermoplastic resin B is preferably a polymer compound having a soft segment and a hard segment, and specifically, polyolefin elastomers, styrene elastomers, polyurethane elastomers, amide elastomers, and polyester elastomers are preferred examples. Here, in the present invention, "elastomer" refers to a thermoplastic resin that has rubber elasticity at room temperature.

[0051] In the present invention, it is preferable that 80.0% to 100.0% by mass of the thermoplastic resin B is one or more elastomers selected from the group consisting of the examples described above, namely polyolefin elastomers, styrene elastomers, polyurethane elastomers, amide elastomers, and polyester elastomers.

[0052] In particular, it is preferable that 80.0% to 100.0% by mass of thermoplastic resin B is one or more selected from the group consisting of polyolefin-based elastomers and polyurethane-based elastomers. When a polyolefin-based elastomer is used, a long-fiber nonwoven fabric with excellent elasticity is obtained, and adhesion to other laminated long-fiber nonwoven fabrics and their constituent fibers is good, resulting in a long-fiber nonwoven fabric with excellent dimensional stability. When a polyurethane-based elastomer is used, a long-fiber nonwoven fabric with excellent elasticity is obtained.

[0053] The modulus of elasticity EB of the fiber FB is preferably 0.005 times or more and 0.400 times or less the modulus of elasticity EA of the crimped fiber FA. This relationship promotes the deformation of the fused portion in the long fiber nonwoven fabric, as described later, resulting in a long fiber nonwoven fabric with higher elongation properties. A preferred modulus of elasticity EB is 0.010 times or more and 0.300 times or less the modulus of elasticity EA, and more preferably 0.010 times or more and 0.250 times or less.

[0054] The modulus of elasticity EA of crimped fiber FA and the modulus of elasticity EB of fiber FB are measured and calculated as follows: (i) The non-fused portion of the long fiber nonwoven fabric is finely cut to collect single fibers of 2 mm or more. (ii) The polymer of the single fibers is identified using a micro-Raman spectrometer (e.g., a Raman spectrometer "inVia" manufactured by RENISHAW). (iii) Steps (i) and (ii) are repeated to extract 10 single fibers each of crimped fiber FA and fiber FB. (iv) The modulus of elasticity is measured in units of MPa using an atomic force microscope (AFM) capable of measuring the modulus of elasticity with a probe (cantilever) (e.g., a "Nano-TA2" manufactured by Anasys Instruments). (v) The arithmetic mean of the results obtained by performing the measurement in (iv) on each of the 10 single fibers extracted in (i) to (iii) above is calculated, and the value is rounded to the first decimal place.

[0055] The fibers FB preferably included in the long-fiber nonwoven fabric of the present invention may contain fatty acid amide compounds with 15 to 50 carbon atoms, similar to the crimped fibers FA. Since the thermoplastic resin B readily adheres to the fibers FB, including the fatty acid amide compounds exemplified in [crimped fibers FA, thermoplastic resin A] reduces the interaction between the fibers FB, resulting in a long-fiber nonwoven fabric with excellent stretchability. Among the fatty acid amide compounds, stearic acid amide and erucic acid amide are particularly preferred because they can control the friction of the fibers FB to an appropriate level, resulting in a long-fiber nonwoven fabric with excellent stretchability and tactile properties.

[0056] The fiber FB according to the present invention preferably has an average single fiber diameter of 5.0 μm or more and 50.0 μm or less. Having such a fiber FB allows for a moderate stretch load, resulting in a long-fiber nonwoven fabric with higher stretchability. When the average single fiber diameter is preferably 5.0 μm or more, more preferably 8.0 μm or more, and even more preferably 10.0 μm or more, a long-fiber nonwoven fabric with excellent elasticity is obtained. On the other hand, when the average single fiber diameter is preferably 50.0 μm or less, more preferably 40.0 μm or less, and even more preferably 30.0 μm or less, a long-fiber nonwoven fabric with excellent stretchability is obtained.

[0057] The average single fiber diameter of fiber FB is measured and calculated using the same method as for crimped fiber FA.

[0058] [Long fiber nonwoven fabric] The long fiber nonwoven fabric of the present invention has a fused portion and a non-fused portion, the ratio of the surface roughness Ra of the fused portion to the thickness Tb of the fused portion (Ra / Tb) is 0.20 or more and 0.80 or less, and the elongation recovery rate of the long fiber nonwoven fabric is 50% or more and 99% or less.

[0059] In this invention, the "fused portion" refers to a portion formed by pressing the long-fiber nonwoven fabric in the cross-sectional direction (thickness direction) with a heated embossing roll, as described later. Therefore, as illustrated in Figure 2A2, this fused portion is a part of the long-fiber nonwoven fabric that is thinner than the surrounding area, and as illustrated in Figure 3A3 and Figure 4A4, the fiber cross-sectional shape is deformed to the extent that it differs from the shape of the other parts, and furthermore, the fibers are melted to the point where parts of the area become lumpy or film-like, and the fibers are fused together. The "non-fused portion" refers to any area other than this "fused portion".

[0060] The long-fiber nonwoven fabric of the present invention has a ratio (Ra / Tb) of surface roughness Ra to thickness Tb at the fused portion of the fabric to be 0.20 or more and 0.80 or less. This long-fiber nonwoven fabric exhibits excellent stretchability.

[0061] In conventional long-fiber nonwoven fabrics with fused joints, strong fusion is applied to ensure strength and abrasion resistance. As shown in Figure 3, the fused joints are flat and do not take deformation under stretching into consideration. Therefore, when conventional long-fiber nonwoven fabrics with fused joints are stretched, the fused joints cannot deform, resulting in uneven stress distribution in the fibers near the fused joints and causing holes to form. After diligent research into the issue of holes forming in conventional long-fiber nonwoven fabrics during stretching, the present invention controls the ratio of the surface roughness Ra to the thickness Tb of the fused joint to create a stress distribution in the fused joint and promote stress diffusion. This allows deformation not only in the fibers of the non-fused parts but also in the fused joint itself, resulting in high stretchability.

[0062] Regarding the above range of the ratio (Ra / Tb) of surface roughness Ra to thickness Tb in the fused portion, a ratio of 0.20 or higher, preferably 0.25 or higher, and more preferably 0.30 or higher results in a long-fiber nonwoven fabric with excellent stretchability. On the other hand, regarding the above range of the ratio (Ra / Tb), a ratio of 0.80 or lower, preferably 0.75 or lower, and more preferably 0.70 or lower results in a long-fiber nonwoven fabric that can be stretched uniformly.

[0063] The ratio (Ra / Tb) of the surface roughness Ra of the fused portion to the thickness Tb of the fused portion is measured and calculated as follows: (i) The thickness Tb (μm) of the fused portion of the long-fiber nonwoven fabric is determined by the following procedure (i-1) to (i-3): (i-1) An image is taken of a cross-section perpendicular to the surface of the long-fiber nonwoven fabric using a scanning electron microscope (SEM) at a magnification that allows observation of the thickness of the spunbond nonwoven fabric. (i-2) The thickness of the fused portion is measured in μm using the captured cross-sectional image of the long-fiber nonwoven fabric. (i-3) The same measurement as in (i-1) and (i-2) is performed for 30 fused portions of the long-fiber nonwoven fabric. The arithmetic mean of the results is calculated and rounded to the first decimal place, and this value is taken as the thickness Tb of the fused portion. (ii) Determine the surface roughness Ra (μm) of the fused portion of the long-fiber nonwoven fabric using the following procedure (iii-1) to (iii-4). (iii-1) Randomly take a 25 mm x 40 mm test piece from the long-fiber nonwoven fabric from a part that is free of wrinkles and folds. (iii-2) Place the test piece on the measuring stand of a laser microscope (for example, "VK-X3000" manufactured by Keyence Corporation). (iii-3) Measure the surface roughness of any fused portion in μm. (iii-4) Perform the same measurements as in (iii-1) to (iii-3) above for 30 fused portions of the long-fiber nonwoven fabric, calculate the arithmetic mean of the results, and round the value to the first decimal place. This value is taken as the surface roughness Ra of the fused portion. (iii) Using the results measured in (i) and (ii) above, calculate the ratio of the surface roughness Ra to the thickness Tb (Ra / Tb) in the fused portion and round it to the third decimal place.

[0064] The long-fiber nonwoven fabric of the present invention has an elongation recovery rate of 50% to 99%. This elongation recovery rate of 50% or more, preferably 60% or more, and more preferably 70% or more, results in a long-fiber nonwoven fabric that provides a comfortable, body-hugging fit when used as a material for wearable items such as sanitary materials like disposable diapers. While a higher elongation recovery rate is preferable for the long-fiber nonwoven fabric, in reality, it is typically 99% or less.

[0065] The elongation recovery rate in this invention is measured and calculated by the following method: (i) A tensile test is performed on the long-fiber nonwoven fabric to determine the angle at which the maximum point elongation is lowest. (i-1) One arbitrary direction of the sample is set as 0 degrees, and five test pieces measuring 200 mm vertically and 50 mm horizontally are randomly cut from the sample from that direction. If test pieces of the specified size cannot be obtained from the sample, a size that can be obtained is determined, and five test pieces of the same size are cut. If the sample to be measured has both fused and unfused parts, both are included in the test pieces. (i-2) Using a tensile testing machine (for example, "TENSILON" "UCT-100" manufactured by Orientec Co., Ltd.), the test piece is stretched with an initial length of 100 mm and a tensile speed of 100% / min, and the elongation rate (maximum point elongation) showing the maximum load is measured. If a test specimen of the specified size cannot be obtained from the sample, the initial length is determined within the range that can be attached to the apparatus, and the test specimen is stretched at a tensile speed of 100% / min. (i-3) The operation in (i-2) above is performed on all five test specimens, the arithmetic mean is calculated, and the result is rounded to the first decimal place, and this is taken as the maximum elongation at 0 degrees. (i-4) For a total of five directions (30 degrees, 60 degrees, 90 degrees, 120 degrees, 150 degrees) with angles changing by 30 degrees from the 0-degree direction, five test specimens measuring 200 mm in length and 50 mm in width are randomly cut from the sample, and the same operation as in (i-2) to (i-3) above is performed in each direction. If a test specimen of the specified size cannot be obtained from the sample, the size that can be obtained is determined, and five test specimens of the same size are cut. If the sample to be measured has both fused and unfused parts, both should be included in the test specimens. (i-5) Determine the direction that shows the smallest value among the maximum point elongation obtained for each angle. (ii) Perform a stretch test on the long-fiber nonwoven fabric and measure the elongation recovery rate. (ii-1) Cut five test pieces randomly from the sample, each measuring 200 mm in the same direction as the direction with the lowest maximum point elongation determined in procedure (i) above, and 50 mm in the direction perpendicular to it. If it is not possible to obtain test pieces of the specified size from the sample, determine an obtainable size and cut five test pieces of the same size. If the sample to be measured has both fused and unfused parts, cut the test pieces so that both are included.(ii-2) Using a tensile testing machine similar to the one used for the tensile test described above, the test specimen is pulled with an initial length (distance between chucks) of 100 mm and a tensile speed of 200% / min until the elongation of the test specimen reaches 100% (i.e., until the distance between chucks becomes 200 mm), and then left to stand for 1 minute. If a test specimen of the specified size cannot be obtained from the sample, the initial length is determined within the range that can be attached to the device, and the test specimen is pulled with a tensile speed of 200% / min until the elongation of the test specimen reaches 100% (i.e., until the distance between chucks becomes twice the initial length). (ii-3) After that, the specimen is returned to its original position (i.e., until the distance between chucks becomes the initial length) at 200% / min and left to stand for 3 minutes. (ii-4) Next, the test specimen is pulled again at a tensile speed of 200% / min, and the distance between the chucks (mm) when the load reaches 0.02 N is measured. The value obtained by subtracting the initial length (mm) from the distance between the chucks (mm) at this time (mm) is then expressed as a percentage (for example, if the distance between the chucks is 103 mm, then (103 mm - 100 mm) / 100 mm is 3%). (ii-5) The same procedure as (ii-3) to (ii-4) above is performed on a total of five test specimens, the arithmetic mean is calculated, and the value is rounded to the first decimal place to calculate the elongation recovery rate using the following formula. Elongation recovery rate = [Distance between chucks (mm) - Initial length (mm)] / Initial length (mm) × 100 The long-fiber nonwoven fabric of the present invention allows for uniform stretching of the fibers in the non-fused portions by having both non-fused and fused portions coexist, resulting in excellent elongation properties. For this reason, it is preferable that the fused portions be arranged in a regular pattern in the long-fiber nonwoven fabric.

[0066] Whether or not a regular pattern exists is determined by the following method: (i) Take a height chart of the surface of the long-fiber nonwoven fabric. (i-1) Randomly take a 25 mm x 40 mm test piece from the long-fiber nonwoven fabric from an area without wrinkles or folds. (i-2) Place the test piece on the measuring stand of a 3D microscope (for example, Keyence Corporation's "VR-3050"). (i-3) Place a plastic plate measuring 80 mm x 80 mm and 1 mm thick with a 20 mm x 20 mm hole in the center on top of the test piece, so that one half of the hole (10 mm x 20 mm) is occupied by the test piece, and fix the test piece so that it is horizontal to the measuring stand. (i-4) Observe the test piece inside the hole of the plastic plate at a magnification of 50x, and take a height chart with the thinner parts marked in white and the thicker parts in black. (ii) Next, the captured images are binarized using image analysis software (National Institutes of Health "ImageJ"), and the geometric centroid of each fused part observed in the image is determined. Here, the image binarization process is performed by setting the following, for example, in "ImageJ": (ii-1) Convert the captured height chart to grayscale (8-bit). (ii-2) Create a histogram of the grayscale height chart and calculate the average value. Set the calculated average value as the threshold and binarize. (iii) Calculate the distance between the centroid of any fused part and the fused part with the closest centroid distance in units of mm, and round to the third decimal place. (iv) Similarly, measure to find the centroid distance of 100 fused parts, calculate the CV% for the obtained 100 results, and determine that the fused parts have a regular pattern when the CV% is 30% or less.

[0067] Furthermore, it is preferable that the area ratio of the fused portion in the long-fiber nonwoven fabric of the present invention is 0.30 or less. A fused portion area ratio of 0.30 or less allows the fibers in the non-fused portion to deform uniformly, resulting in a long-fiber nonwoven fabric with higher stretchability. On the other hand, from the viewpoint of increasing the strength of the long-fiber nonwoven fabric, it is preferable that the area ratio of the fused portion is 0.05 or more.

[0068] The area ratio of the fused portion in this invention is measured and calculated as follows: (i) The image captured and binarized is used when determining the distance between the centroids of the fused portion as described above. (ii) For all fused portions observable in the image, the unit is mm. ２ The area Ab of the fused part is calculated, and the area size of the image (mm) is determined. ２ (iii) Calculate the value obtained by dividing by ( ). Images taken at 20 locations arbitrarily extracted from the long-fiber nonwoven fabric are obtained in the same manner as above, the arithmetic mean is calculated and rounded to the third decimal place.

[0069] In the long-fiber nonwoven fabric of the present invention, it is preferable that the ratio of crimped fibers FA on at least one surface is 50% or more. Preferably, it is 50% or more, more preferably 60% or more, and even more preferably 75% or more, which results in a long-fiber nonwoven fabric with excellent tactile properties.

[0070] The ratio of crimped fibers FA on the surface of the long-fiber nonwoven fabric, as used here, is measured and calculated as follows: (i) The crimped fibers FA are extracted from the long-fiber nonwoven fabric using the following procedure (i-1) to (i-5), and the Raman spectrum of the crimped fibers FA is identified. (i-1) One 2 cm x 2 cm test piece is randomly cut from the long-fiber nonwoven fabric. (i-2) In the extracted test piece, the areas where the fibers are not fused together are finely cut with scissors to create small pieces of fiber (pieces approximately 0.5 mm square). (i-3) The small pieces of fiber prepared in (i-2) are observed with a scanning electron microscope (SEM, for example, Keyence Corporation's "VHX-6000"), and crimped fibers that satisfy the following two conditions and are curved as shown in Figure 1 are searched for, and an image is taken at a magnification of 400x or higher. Conditions: The fiber does not overlap with other fibers and can be observed independently. Conditions: The fiber length is 200 μm or more and 1000 μm or less. (i-4) For the captured image, the radius of curvature of the inner contour of the curved shape and the outer contour of the curved shape are measured in μm, and the arithmetic mean of these is calculated. If the radius of curvature is 1500 μm or less, the observed fiber is identified as crimped fiber FA. (i-5) For the fiber sample identified as crimped fiber FA by measuring the radius of curvature, the Raman spectrum is measured using micro-Raman spectroscopy to obtain the Raman spectrum of the crimped fiber FA. In this case, the beam spot diameter of the measurement light is preferably sufficiently small compared to the fiber diameter, for example, 1 μm to 2 μm is preferred. (ii) One surface of the long fiber nonwoven fabric is labeled as surface 1 and the other surface as surface 2 on the sample, and a 1 cm × 1 cm sample is cut out. (iii) Observe the surface 1 of the cut sample at a magnification that allows observation of 50 or more fibers, and measure the Raman spectrum of all observable fibers using micro-Raman spectroscopy. In this case, the beam spot diameter of the measurement light is preferably sufficiently small compared to the fiber diameter, for example, 1 μm to 2 μm is preferred. (iv) From the obtained Raman spectrum, count the number of fibers that have the same spectrum as the crimped fiber FA determined in (i) above, and this is the number of crimped fibers FA. (iv) Calculate the number of crimped fibers FA relative to the total number of observed fibers in %, in units of %.(v) The same measurements as in (i) to (iv) above are performed at 20 locations on the long-fiber nonwoven fabric. The arithmetic mean of the results is calculated and rounded to the first decimal place. This value is the ratio of crimped fibers FA on surface 1. (vi) For all samples cut out during the measurement of surface 1, the same measurements as in (ii) to (v) above are performed on surface 2 to determine the ratio of crimped fibers FA on surface 2. If either the ratio of crimped fibers FA on surface 1 or the ratio of crimped fibers FA on surface 2 is 50% or more, then it is said that the ratio of crimped fibers FA is 50% or more on at least one of the surfaces.

[0071] The long-fiber nonwoven fabric of the present invention may consist only of a layer of crimped fibers FA (referred to as the O layer), i.e., a single layer. Furthermore, it may be laminated with the O layer on one surface and a long-fiber nonwoven fabric layer (referred to as the I layer) composed of fibers FB mainly composed of thermoplastic resin B, which is different from thermoplastic resin A, on the other surface, or with the O layer laminated on both surfaces, or even with the layers laminated in the order of O layer / I layer / O layer. Moreover, an embodiment in which another long-fiber nonwoven fabric layer different from both the O layer and the I layer (for example, a layer that is spunbond nonwoven fabric, a layer that is meltblown nonwoven fabric) is laminated is also preferred.

[0072] The layer (O layer) composed of crimped fibers FA mainly composed of the thermoplastic resin A is, more specifically, a spunbond nonwoven fabric or a meltblown nonwoven fabric formed by a method described later. A spunbond nonwoven fabric is more preferable from the viewpoint that the elastic modulus of the crimped fibers FA can be suitably controlled by molecular orientation control.

[0073] Furthermore, when laminating a long-fiber nonwoven fabric layer (Layer I) composed of fiber FB, it is preferable to use a spunbond nonwoven fabric or a meltblown nonwoven fabric formed by the method described later. In particular, spunbond nonwoven fabric is more preferable because the elastic modulus of the fiber FB can be suitably adjusted by molecular orientation.

[0074] The long-fiber nonwoven fabric of the present invention has an apparent density of 0.020 g / cm³ after 100% stretching. ３ 0.200g / cm or more ３The following conditions are preferable because they result in a long-fiber nonwoven fabric with excellent tactile properties: Apparent density is preferably 0.200 g / cm³. ３ More preferably, 0.180 g / cm³ ３ More preferably, 0.160 g / cm³ ３ The following conditions result in a long-fiber nonwoven fabric that offers excellent breathability and flexibility, as well as high bulkiness. On the other hand, the apparent density is preferably 0.020 g / cm³. ３ The above is a more preferable 0.030 g / cm³. ３ As a result of meeting the above conditions, a long-fiber nonwoven fabric with excellent morphological stability is obtained.

[0075] In this invention, the apparent density of the long-fiber nonwoven fabric after 100% stretching refers to the value calculated by the following formula: Apparent density after 100% stretching (g / cm³) ３ ) = Basis weight (g / m²) after 100% stretching ２ ) / Thickness after 100% stretching (mm) / 1000 The basis weight and thickness shall be the values ​​measured and calculated using the following procedure. (i) Measurement of basis weight after 100% stretching (i-1) Using the same method as the measurement of the elongation recovery rate described above, five test pieces are randomly cut from the long-fiber nonwoven fabric, each measuring 200 mm in the same direction as the direction with the lowest maximum elongation and 50 mm in the direction perpendicular to it. (i-2) Using the same tensile testing machine as the measurement of the elongation recovery rate described above, the test piece is stretched with an initial length of 100 mm and a tensile speed of 200% / min until the elongation rate of the test piece reaches 100%, and then left to stand for 1 minute. (i-3) After that, it is returned to its original position at 200% / min and left to stand for 3 minutes. (i-4) Remove the test specimen from the tensile testing machine, cut off the portion other than the stretched part, and then weigh the mass (g) of each part in its standard state according to "6.2 Mass per unit area" of JIS L1913:2010 "General Nonwoven Fabric Test Methods", and measure 1 m ２ Mass per unit (g / m³) ２ ) calculate (i-5) Repeat the above steps (i-2) to (i-4) for 1 m for 5 test pieces. ２ The mass per unit is measured and calculated, and the average value is used to determine 1 m ２ Mass per unit (g / m³) ２) is calculated and this is taken as the basis weight after 100% stretching. (ii) Measurement of thickness after 100% stretching (ii-1) The test piece used for measuring the basis weight is placed on a shape measuring machine (for example, Keyence Corporation's "VR-3050"). (ii-2) A plastic plate measuring 80 mm x 80 mm and 1 mm thick with a 20 mm x 20 mm hole in the center is placed on the test piece so that one half of the hole (10 mm x 20 mm) is occupied by the test piece, and the test piece is fixed so that it is horizontal to the measuring stand. (ii-3) The thickness of the test piece inside the hole in the plastic plate is measured at 8 random points in units of μm. (ii-4) The arithmetic mean of the measured values ​​is calculated in units of μm and rounded to the first decimal place. (ii-5) Repeat the procedures (ii-2) to (ii-4) above to measure the thickness of five test pieces, calculate the average value, and use this as the thickness after stretching.

[0076] Furthermore, the long-fiber nonwoven fabric of the present invention is preferable because its elongation at break is 120% or more and 400% or less, making it less prone to punctures and possessing good stretchability. Preferably, the elongation at break is 120% or more, and more preferably 140% or more. On the other hand, if the elongation at break is preferably 400% or less, and more preferably 300% or less, the long-fiber nonwoven fabric will stop stretching at an appropriate position when used as a material for wearable items such as sanitary materials like disposable diapers.

[0077] The elongation at break of the long-fiber nonwoven fabric as referred to in this invention is measured and calculated as follows, based on "6.3 Tensile strength and elongation" of JIS L1913:2010 "General nonwoven fabric test methods": (i) One arbitrary direction of the sample is defined as 0 degrees, and five test pieces are randomly cut from the sample, each measuring 200 mm in the 0-degree direction and 50 mm in the 90-degree direction. (ii) The test pieces are mounted on a tensile testing machine (for example, "TENSILON" "UCT-100" manufactured by Orientec Co., Ltd.), and the test pieces are stretched with an initial length of 100 mm and a tensile speed of 100% / min, and the elongation showing the maximum stress (maximum point elongation) is measured. (iii) The operation in (ii) above is performed on the five test pieces, the arithmetic mean is calculated, and the result is rounded to the first decimal place, and this is taken as the maximum point elongation at 0 degrees. (iv) The same operations as in (i) to (iii) above are performed in a total of five directions (30 degrees, 60 degrees, 90 degrees, 120 degrees, 150 degrees) by changing the angle by 30 degrees from the 0-degree direction. (v) The maximum point elongation in the direction showing the smallest value among the maximum point elongations obtained for each angle is taken as the breaking elongation of the long-fiber nonwoven fabric.

[0078] [Laminate] The long-fiber nonwoven fabric of the present invention may further have another layer laminated to it. That is, the laminate according to the present invention has the long-fiber nonwoven fabric and a layer different from the long-fiber nonwoven fabric. Here, "a layer different from the long-fiber nonwoven fabric" means a layer whose structure is different from that of the long-fiber nonwoven fabric. Examples of a layer whose structure is different from that of the long-fiber nonwoven fabric include short-fiber nonwoven fabrics such as papermaking nonwoven fabrics and carding nonwoven fabrics, meshes such as woven fabrics and knitted fabrics, films, and superabsorbent polymers (SAP).

[0079] [Method for manufacturing long fiber nonwoven fabric] One preferred embodiment of the method for manufacturing the long fiber nonwoven fabric of the present invention includes: (a-1) a step of extruding a polymer stream containing the thermoplastic resin A and a thermoplastic resin B different from the thermoplastic resin A from a spinneret to form a web; and (a-2) a step of pressurizing the web with a roll having a surface temperature of TmB-50°C or more and TmB+70°C or less, where TmB is the melting point of the thermoplastic resin B.

[0080] (a-1) Web Forming Process This process involves extruding a polymer stream containing the thermoplastic resin A and a thermoplastic resin B different from the thermoplastic resin A from a spinneret to form a web. This web is preferably a nonwoven fabric formed by the spunbond method or the meltblown method (spunbond nonwoven fabric and meltblown nonwoven fabric, respectively). The spunbond method is particularly preferable because it allows for easy and high molecular orientation, and as will be described later, it allows for favorable control of the radius of curvature of the crimped fibers FA.

[0081] The spunbond method is a method of producing nonwoven fabrics in which a thermoplastic resin, which is the raw material, is melted, spun from a spinneret, and then the resulting yarn is pulled by high-speed air, and the yarn is collected on a moving collection belt to obtain a web.

[0082] In this process, it is preferable to use a thermoplastic resin with high crystallinity for the thermoplastic resin A used in order to maintain the fiber shape and control the unevenness of the fused portion in the process of forming the fused sheet described later.

[0083] For example, aromatic polyester polymers and their copolymers, aliphatic polyester polymers and their copolymers, aliphatic polyamide polymers and their copolymers, and polyolefin polymers and their copolymers are particularly preferred because they have appropriate crystallinity and a suitable modulus of elasticity.

[0084] Furthermore, it is preferable to add 0.1% to 5.0% by mass of a fatty acid amide compound having 15 to 50 carbon atoms to the thermoplastic resin A before spinning. This reduces the likelihood of yarn breakage during the spinning process and stabilizes the process. The fatty acid amide compounds used are those exemplified in the above-mentioned [Crimped Fiber FA, Thermoplastic Resin A] section. Among these, stearic acid amide and erucic acid amide are particularly preferred because they have excellent heat resistance, preventing excessive decomposition when the thermoplastic resin melts and allowing for appropriate friction control on the fibers.

[0085] It is preferable that the elastic modulus EB of the thermoplastic resin B used in this process be 0.005 times or more and 0.400 times or less of the elastic modulus EA of the thermoplastic resin A, so that in the process of forming the fused sheet described later, the thermoplastic resin A in the crimped fiber FA does not deform, only the thermoplastic resin B can deform, a suitable uneven surface can be formed in the fused portion, and a long-fiber nonwoven fabric with excellent stretchability can be obtained.

[0086] The elastic modulus of each thermoplastic resin referred to herein is the value obtained by measuring the elastic modulus of the raw material chip using the following method: (i) The raw material chip is fixed to an atomic force microscope (AFM) capable of measuring the elastic modulus with a probe (cantilever) (for example, "Nano-TA2" manufactured by Anasys Instruments, Inc.), and the elastic modulus is measured in units of MPa. (ii) The arithmetic mean of the results obtained by performing the measurement in (i) on 10 raw material chips is calculated, and the value is rounded to the first decimal place.

[0087] A more preferable range for the elastic modulus of the thermoplastic resin B is 0.010 times or more and 0.400 times or less the elastic modulus EA.

[0088] The thermoplastic resin B used in this process is different from thermoplastic resin A, and is preferably a polymer compound having a soft segment and a hard segment, which allows for easy control of its elastic modulus. Specifically, polyolefin elastomers, styrene elastomers, polyurethane elastomers, amide elastomers, and polyester elastomers are preferred examples.

[0089] The thermoplastic resin B used in this process may be of one type, but by including multiple thermoplastic resins B, the elastic modulus EB can be suitably controlled.

[0090] Furthermore, it is preferable to add 0.01% to 5.0% by mass of a fatty acid amide compound to the thermoplastic resin B before spinning, as this suppresses yarn breakage during the spinning process and thus stabilizes the process. The fatty acid amide compounds used are those exemplified in [Thermoplastic Resin A, Fiber FA] above. Among these, stearic acid amide and erucic acid amide are particularly preferred because they have excellent heat resistance, preventing excessive decomposition when the thermoplastic resin melts, allowing for appropriate friction on the fibers, and suppressing adhesion to the spinning equipment.

[0091] The spinneret used to form the web in this process can have either a round or irregularly shaped hole, but a round hole is preferable as it provides spinning stability. In particular, it is preferable to perform composite spinning to induce crimp in the crimped fiber FA, in which case a spinneret equipped with a mechanism capable of forming a side-by-side composite cross section or an eccentric core-sheath composite cross section is used. When using the spinneret, the polymer viscosity and discharge ratio of the crimped fiber FA are adjusted so that the desired elongation of the long-fiber nonwoven fabric is obtained.

[0092] The spinning speed when forming the web in this process is preferably 2000 m / min or more, more preferably 3000 m / min or more. The spinning speed is the speed ultimately reached by high-speed pneumatic traction. By setting the spinning speed to 2000 m / min or more, the orientation and crystallization of the fibers are promoted, the elastic modulus of the crimped fibers FA can be increased, and a long-fiber nonwoven fabric with excellent elongation properties can be obtained. On the other hand, the spinning speed is preferably 8000 m / min or less, more preferably 7000 m / min or less. By defining an upper limit on the spinning speed, a flexible long-fiber nonwoven fabric can be obtained.

[0093] (a-2) Process for forming a fused sheet This process involves pressing the obtained web with a roll having a surface temperature of TmB-50°C or higher and TmB+70°C or lower, where TmB is the melting point of the thermoplastic resin B, to form a fused sheet having fused and unfused portions.

[0094] The rolls used in this process are preferably those that form a regular pattern of fused portions on the web, and more specifically, a pair of rolls consisting of an embossing roll and a flat roll having a regular pattern is preferred.

[0095] Here, an embossed roll having a regular pattern is, for example, one in which protrusions (convex parts) are formed in the parts corresponding to the fusion area, or concave shapes are formed in the parts not corresponding to the fusion area. In particular, it is preferable if further irregularities are formed on the top of the convex parts corresponding to the fusion area, or if the top part is curved, as this makes it easier to create irregularities in the fusion area and allows for easy control of the ratio of surface roughness to thickness of the fusion area.

[0096] Regarding the fused portions that are formed, it is preferable that the spacing between adjacent fused portions is 50 μm or more and 20 mm or less, as this allows for the production of a long-fiber nonwoven fabric that has flexibility, excellent stretchability, and excellent dimensional stability. The spacing between adjacent fused portions referred to here is the arithmetic mean (μm) obtained by calculating the distance between the centroids of 100 fused portions of the obtained long-fiber nonwoven fabric in μm using the method described above, and rounding it to the first decimal place.

[0097] The area ratio of the top portion of the convex part corresponding to the fused portion of the embossing roll is preferably 0.30 or less, as this allows for appropriate control of the ratio of the fused portion of the long-fiber nonwoven fabric. The area ratio of the top portion referred to here is the value obtained by rounding the ratio of the area of ​​the top portion to the area calculated from the diameter and length of the embossing roll to the third decimal place.

[0098] The surface temperature of the roll is preferably set to TmB-50°C or higher and TmB+70°C or lower, where TmB (°C) is the melting point of thermoplastic resin B. This is preferable because, in the pressurized portion of the roll, the shape of the thermoplastic resin A, which has a high modulus of elasticity, is maintained, while the shape of the thermoplastic resin B, which has a low modulus of elasticity, cannot be maintained and deforms. This makes it easier to create irregularities in the fused portion and to control the ratio of surface roughness to thickness of the fused portion. More preferably, the surface temperature of the roll is set to TmB-50°C or higher and TmB+50°C or lower, and even more preferably to TmB-50°C or higher and TmB+30°C or lower, which yields a long-fiber nonwoven fabric with excellent morphological stability. In this invention, the surface temperature of the roll is the average value of the results of five measurements taken in the circumferential direction of the roll at the center of the roll in the width direction. In the case of a pair of rolls, the above measurements are performed on both rolls, and the average value is taken as the surface temperature of the rolls.

[0099] From the viewpoint of maintaining the elastic modulus of the thermoplastic resin A, the surface temperature is preferably TmA - 30°C or lower, and particularly preferably TmA - 40°C or lower, where TmA (°C) is the melting point of the thermoplastic resin A.

[0100] TmA and TmB are measured as follows: (i) Take a 3 mg sample from the thermoplastic resin. (ii) Using a differential scanning calorimeter (e.g., TA Instruments' "DSCQ2000"), heat the sample from 20°C to 300°C in a nitrogen atmosphere at a heating rate of 16°C / min to melt it. Obtain a graph with temperature (°C) on the horizontal axis and heat absorption (mW / mg) on ​​the vertical axis. (iii) Calculate the temperature (°C) of the peak with the largest heat absorption among the endothermic peaks that appear on the graph. (iv) Repeat steps (i) to (iii) 10 times and round the melting point (°C) of the obtained thermoplastic resin to the first decimal place.

[0101] Furthermore, when measuring TmA and TmB from crimped fiber FA, the measurement is performed as follows: (i) Take a 3 mg test specimen from the crimped fiber FA. (ii) Using a differential scanning calorimeter (for example, "DSCQ2000" manufactured by TA Instruments), heat the specimen from 20°C to 300°C in a nitrogen atmosphere at a heating rate of 16°C / min to melt it. At that time, obtain a graph in which the horizontal axis is temperature (°C) and the vertical axis is the amount of heat absorbed (mW / mg). (iii) Since multiple endothermic peaks appear on the graph, calculate the temperature (°C) at the peak of the peak with the largest amount of heat absorbed and the temperature (°C) at the peak of the second largest amount of heat absorbed. (iv) Repeat steps (i) to (iii) above 10 times, and TmA (°C) is the value obtained by rounding the arithmetic mean of the temperatures at the peaks with the largest endothermic values ​​obtained in each measurement to the first decimal place, and TmB (°C) is the value obtained by rounding the arithmetic mean of the temperatures at the peaks with the second largest endothermic values ​​obtained in each measurement to the first decimal place.

[0102] In this case, it is preferable that the linear pressure applied by the roll be between 0.5 N / cm and 5.0 N / cm. By applying pressure at such a linear pressure and forming the fused sheet, the deformation of the crimped fiber FA can be maintained, and the ratio of surface roughness to thickness of the fused portion can be controlled.

[0103] One preferred embodiment of the method for producing a long-fiber nonwoven fabric of the present invention includes: (b-1) a step of forming a web A composed of crimped fibers FA mainly composed of the thermoplastic resin A; (b-2) a step of forming a web B composed of fibers FB mainly composed of a thermoplastic resin B different from the thermoplastic resin A; (b-3) a step of producing a laminated web by laminating the web A and the web B; and (b-4) a step of pressurizing the laminated web with a surface roll at a temperature of TmB - 50°C or higher and TmB + 70°C or lower, where TmB is the melting point of the thermoplastic resin B, to form a fused sheet having fused portions and non-fused portions.

[0104] The following provides a more detailed explanation of each of the above steps.

[0105] (b-1) Step to form web A First, in this step, a web A is formed which includes crimped fibers FA mainly composed of the thermoplastic resin A. This web A is preferably a nonwoven fabric formed by the spunbond method or the meltblown method (spunbond nonwoven fabric and meltblown nonwoven fabric, respectively). The spunbond method is particularly preferable because it is easy to increase molecular orientation, and as will be described later, the radius of curvature of the crimped fibers FA can be suitably controlled.

[0106] In this process, it is preferable to use a thermoplastic resin A with high crystallinity in order to maintain the fiber shape and control the unevenness of the fused portion in the process of forming the fused sheet described later. For example, aromatic polyester polymers and their copolymers, aliphatic polyester polymers and their copolymers, aliphatic polyamide polymers and their copolymers, and polyolefin polymers and their copolymers are preferred because they have appropriate crystallinity and suitable elastic modulus.

[0107] Furthermore, it is preferable to add 0.1% to 5.0% by mass of a fatty acid amide compound having 15 to 50 carbon atoms to the thermoplastic resin A before spinning. This reduces the likelihood of yarn breakage during the spinning process and stabilizes the process. The fatty acid amide compounds used are those exemplified in the above-mentioned [Crimped Fiber FA, Thermoplastic Resin A] section. Among these, stearic acid amide and erucic acid amide are particularly preferred because they have excellent heat resistance, preventing excessive decomposition when the thermoplastic resin melts and allowing for appropriate friction control on the fibers.

[0108] When forming the web A according to the present invention, a spinneret with a round hole or an irregularly shaped hole can be used as appropriate, but a round hole is preferred from the viewpoint of spinning stability. In particular, it is a preferred embodiment to perform composite spinning in order to induce crimp in the crimped fiber FA, in which case a spinneret equipped with a mechanism that can form a side-by-side type composite cross section or an eccentric core-sheath composite cross section can be used.

[0109] When using such a spinneret, the viscosity and discharge ratio of the crimped fiber FA polymer should be adjusted to obtain the desired elongation properties of the long-fiber nonwoven fabric.

[0110] The spinning speed, which is the speed ultimately reached by high-speed air traction when forming web A according to the present invention, is preferably 2000 m / min or more, and more preferably 3000 m / min or more. By setting the spinning speed to 2000 m / min or more, the orientation and crystallization of the fibers are promoted, the elastic modulus of the crimped fibers FA can be increased, and a long-fiber nonwoven fabric with excellent elongation properties can be obtained. On the other hand, the spinning speed is preferably 8000 m / min or less, and more preferably 7000 m / min or less. By doing so, a long-fiber nonwoven fabric with excellent flexibility can be obtained.

[0111] (b-2) Process for forming web B In this process, a web B is formed, which is composed of fibers FB mainly made of thermoplastic resin B, different from the thermoplastic resin A. This web B is preferably a nonwoven fabric formed by the spunbond method or the meltblown method, and more preferably a nonwoven fabric formed by the spunbond method.

[0112] The thermoplastic resin B referred to here is the thermoplastic resin B described above.

[0113] The modulus of elasticity EB of the thermoplastic resin B used in this process is preferably set to 0.005 times or more and 0.400 times or less of the modulus of elasticity EA of the thermoplastic resin A. This creates a difference in the amount of deformation of the crimped fibers FA and fibers FB in the process of forming the fused sheet described later, which allows for the formation of suitable irregularities in the fused portion and enables the production of a long-fiber nonwoven fabric with excellent stretchability. From this viewpoint, the modulus of elasticity EB is more preferably 0.010 times or more and 0.400 times or less of EA.

[0114] The thermoplastic resin B used in this process may be of one type, but from the viewpoint of suitably controlling the elastic modulus EB, it may contain multiple types of thermoplastic resin B.

[0115] Furthermore, it is preferable to add 0.01% to 5.0% by mass of a fatty acid amide compound to the thermoplastic resin B before spinning, as this suppresses yarn breakage during the spinning process and thus stabilizes the process. The fatty acid amide compounds used are those exemplified in [Thermoplastic Resin A, Fiber FA] above. Among these, stearic acid amide and erucic acid amide are particularly preferred because they have excellent heat resistance, preventing excessive decomposition when the thermoplastic resin melts, allowing for appropriate friction on the fibers, and suppressing adhesion to the spinning equipment.

[0116] In this process, the fiber FB may be a single-component fiber mainly composed of the thermoplastic resin B, or a composite fiber made of thermoplastic resin B of different compositions.

[0117] The spinning speed, which is the speed ultimately reached by high-speed air traction when forming web B according to the present invention, is preferably 500 m / min or more, and more preferably 700 m / min or more. By setting the spinning speed to 500 m / min or more, a uniform web can be obtained, and when it becomes a long-fiber nonwoven fabric, stress distribution is achieved and good elongation is obtained. On the other hand, the spinning speed is preferably 8000 m / min or less, and more preferably 7000 m / min or less. By doing so, web B can be obtained stably without yarn breakage.

[0118] (b-3) Process for manufacturing a laminated web This process involves laminating web A and web B to obtain a laminated web. The laminated web is selected according to the purpose of use, etc., and as described above, when it becomes a long fiber nonwoven fabric, it has the following configurations, namely, a layer (O layer) made of crimped fibers FA mainly composed of thermoplastic resin A on one surface side, and a long fiber nonwoven fabric layer (I layer) made of fibers FB mainly composed of thermoplastic resin B different from thermoplastic resin A on the other surface side, a layer O layer is laminated on both surface sides, and a layer O layer / I layer / O layer is laminated in that order, and so on, including multiple long fiber nonwoven fabric layers.Specific laminated configurations of four or more layers not described above include, for example, O layer / I layer / I layer / O layer, O layer / I layer / O layer / I layer, O layer / I layer / O layer / I layer / O layer, O layer / I layer / I layer / I layer / O layer, etc. In particular, a configuration in which layers made of crimped fibers FA, which easily provide a smooth touch, are laminated on both the front and back surfaces of a layer made of fibers FB, which easily provides a rubbery touch, is preferred, that is, a configuration in which layers are laminated in the order of O layer / I layer / O layer, or an order of O layer / I layer / O layer / I layer / O layer. As mentioned above, another long-fiber nonwoven fabric layer different from both the O layer and the I layer may also be laminated.

[0119] (b-4) Step to form a fused sheet In this step, the laminated sheet is pressed with a roll whose surface temperature is between TmB-50°C and TmB+70°C, where TmB is the melting point of the thermoplastic resin B, to form a fused sheet having fused and unfused portions.

[0120] The rolls used in this process are preferably configured to give the laminated sheet a regularly patterned fusion portion, and more specifically, a pair of rolls consisting of an embossing roll and a flat roll having a regularly patterned shape is preferred.

[0121] Here, an embossed roll having a regular pattern is, for example, one in which protrusions (convex parts) are formed in the parts corresponding to the fusion area, or concave shapes are formed in the parts not corresponding to the fusion area. In particular, it is preferable if there are further irregularities formed on the top of the convex parts corresponding to the fusion area, or if the top part is curved, as this makes it easier to create irregularities in the fusion area and allows for easy control of the ratio of surface roughness to thickness of the fusion area.

[0122] Furthermore, by ensuring that the spacing between adjacent fused portions is between 50 μm and 20 mm, it is possible to produce a long-fiber nonwoven fabric that has flexibility, excellent stretchability, and excellent dimensional stability, which is preferable.

[0123] Furthermore, it is preferable that the area ratio of the top portion of the convex part corresponding to the fused portion of the roll is 0.30 or less, as this allows for appropriate control of the ratio of the fused portion of the long-fiber nonwoven fabric. The area ratio of the top portion referred to here is the value obtained by rounding the ratio of the area of ​​the top portion to the area calculated from the diameter and length of the roll to the third decimal place.

[0124] Furthermore, the surface temperature of the roll is preferably set to TmB-50°C or higher and TmB+70°C or lower, where TmB (°C) is the melting point of the thermoplastic resin B. This is preferable because it allows for the creation of a long-fiber nonwoven fabric with excellent dimensional stability, and because the pressure portion of the roll maintains the shape of the thermoplastic resin A, which has a high modulus of elasticity, while the thermoplastic resin B, which has a low modulus of elasticity, deforms without maintaining its shape. This makes it easier to create irregularities in the fused portion and to control the ratio of surface roughness to thickness of the fused portion. Preferably, the surface temperature is TmB-50°C or higher and TmB+50°C or lower, more preferably TmB-50°C or higher and TmB+30°C or lower, and even more preferably TmB-50°C or higher and TmB+20°C or lower.

[0125] From the viewpoint of maintaining the elastic modulus of the thermoplastic resin A, the surface temperature is preferably TmA - 30°C or lower, and particularly preferably TmA - 40°C or lower, when TmA (°C) is the melting point of the thermoplastic resin A. In this case, the pressure applied by the roll is preferably such that the linear pressure of the roll is 0.5 N / cm or more and 5.0 N / cm or less. By applying pressure with such a linear pressure and forming a fused sheet, the deformation of the crimped fiber FA can be maintained, and the ratio of surface roughness to thickness of the fused portion can be controlled.

[0126] One preferred embodiment of the method for producing a long-fiber nonwoven fabric of the present invention includes: (c-1) a step of forming a web A' composed of fibers FA' mainly composed of the thermoplastic resin A'; (c-2) a step of forming a web B composed of fibers FB mainly composed of a thermoplastic resin B different from the thermoplastic resin A'; (c-3) a step of producing a laminated web by laminating the web A' and the web B; and (c-4) a step of pressurizing the laminated web with a surface roll at a temperature of TmB - 50°C or higher and TmB + 70°C or lower, where TmB is the melting point of the thermoplastic resin B, to form a fused sheet having fused portions and non-fused portions.

[0127] The following provides a more detailed explanation of each of the above steps.

[0128] (c-1) Step to form web A' First, in this step, a web A' is formed which includes fibers FA' mainly composed of the thermoplastic resin A'. This web A' is preferably a nonwoven fabric formed by the spunbond method or the meltblown method (spunbond nonwoven fabric and meltblown nonwoven fabric, respectively). The spunbond method is particularly preferable because it is easy to increase molecular orientation, and as will be described later, the difference OC-OS between the molecular orientation parameter OC in the fiber axis direction in the core component of the fiber FA' and the molecular orientation parameter OS in the fiber axis direction in the sheath component can be suitably controlled.

[0129] In this process, the thermoplastic resin A' used is preferably a highly crystalline thermoplastic resin, from the viewpoint of maintaining the fiber shape and controlling the unevenness of the fused portion in the process of forming the fused sheet described later. For example, aromatic polyester polymers and their copolymers, aliphatic polyester polymers and their copolymers, aliphatic polyamide polymers and their copolymers, and polyolefin polymers and their copolymers are preferred because they have appropriate crystallinity and suitable elastic modulus. Highly crystalline polyolefin polymers and their copolymers are more preferred, and among them, propylene polymers that have an appropriate crystallinity rate and can be spun stably are particularly preferred.

[0130] Furthermore, it is preferable to add 0.1% to 5.0% by mass of a fatty acid amide compound having 15 to 50 carbon atoms to the thermoplastic resin A' before spinning, which reduces the likelihood of yarn breakage during the spinning process and stabilizes the process. The fatty acid amide compounds used are those exemplified in the above [Crimped fiber FA, Thermoplastic resin A] section. Among these, stearic acid amide and erucic acid amide are particularly preferred because they have excellent heat resistance, preventing excessive decomposition when the thermoplastic resin melts and allowing for appropriate friction control on the fibers.

[0131] In this process, in order to suitably control the difference OC-OS in the molecular orientation parameters, it is preferable that the properties of the thermoplastic resin A'-C used for the core component and the thermoplastic resin A'-S used for the sheath component are different.

[0132] In this process, the thermoplastic resins A'-C and A'-S are preferably in a state where they have different melt viscosities. Therefore, by setting the ratio (ηC / ηS) of the melt viscosity ηC of the core component thermoplastic resin A'-C to the melt viscosity ηS of the sheath component thermoplastic resin A'-C to 1.2 or more and 5.0 or less, preferably 1.5 or more and 4.0 or less, the core component can be suitably oriented during spinning and the sheath component can maintain a low orientation state, thereby suitably controlling the difference in molecular orientation parameters OC-OS.

[0133] The melt viscosity referred to here is the shear rate at the spinning temperature of 31.4 s. －１This refers to the melt viscosity and is measured by the method described below. (i) Using a rotary rheometer (for example, UBM's "Rheosol-G3000"), the temperature is raised to a temperature equivalent to the spinning temperature. (ii) The polymer is sandwiched between φ20 mm parallel plates, and after melting, the gap between the plates is set to 0.5 mm. (iii) 31.4 rad / s －１ (iv) Under the above conditions, measure the melt viscosity in units of Pa·s.

[0134] In this process, one preferred method for suitably controlling the difference in molecular orientation parameters OC-OS is to reduce the crystallinity of the thermoplastic resin A'-S in order to suppress the solidification of the sheath component and reduce molecular orientation. When homopropylene is used for the thermoplastic resin A'-C, it is preferable to use, for example, ethylene copolymerized homopropylene, a blend polymer of homopropylene and ethylene copolymerized homopropylene, or a blend polymer of homopropylene and atactic homopropylene as the thermoplastic resin A'-S, because the crystallinity is lower than that of homopropylene, the sheath component can be less oriented, and the difference in molecular orientation parameters OC-OS can be suitably controlled.

[0135] When forming the web A' according to the present invention, a spinneret with a round hole or an irregularly shaped hole can be used as appropriate, but a round hole is preferred from the viewpoint of spinning stability. In particular, it is a preferred embodiment to perform composite spinning to obtain a core-sheath type composite cross section fiber FA', in which case a spinneret equipped with a mechanism that can form a concentric core-sheath type composite cross section or an eccentric core-sheath type composite cross section can be used.

[0136] When using such a spinneret, the polymer discharge ratio of fiber FA' can be adjusted to obtain the desired elongation of the long-fiber nonwoven fabric.

[0137] In this process, by setting the ratio of the amount of sheath component polymer discharged to the total amount of polymer discharged to preferably 0.50 to 0.90, and preferably 0.55 to 0.80, the stress on the sheath component during spinning can be appropriately suppressed, and the difference OC-OS of the molecular orientation parameters can be suitably controlled.

[0138] In forming web A' according to the present invention, the spinning speed, which is the speed ultimately reached by high-speed air traction, is preferably 2000 m / min or more, and more preferably 3000 m / min or more. By setting the spinning speed to 2000 m / min or more, the orientation and crystallization of the fibers are promoted, the elastic modulus of the fiber FA' can be increased, and the difference OC-OS of the molecular orientation parameters can be suitably controlled by preferentially oriented the core component, thereby obtaining a long-fiber nonwoven fabric with excellent elongation. On the other hand, the spinning speed is preferably 8000 m / min or less, and more preferably 7000 m / min or less. By doing so, a long-fiber nonwoven fabric with excellent flexibility can be obtained.

[0139] (c-2) Process for forming web B In this process, similar to the process described in (b-2), a web B is formed, which is composed of fibers FB mainly made of the thermoplastic resin B, different from the thermoplastic resin A'. This web B is preferably a nonwoven fabric formed by the spunbond method or the meltblown method, and more preferably a nonwoven fabric formed by the spunbond method.

[0140] The thermoplastic resin B referred to here is the thermoplastic resin B described above.

[0141] The modulus of elasticity EB of the thermoplastic resin B used in this process is preferably set to 0.005 times or more and 0.400 times or less the modulus of elasticity EA' of the thermoplastic resin A'. This creates a difference in the amount of deformation of fibers FA' and FB in the process of forming the fused sheet described later, which allows for the formation of suitable irregularities in the fused portion and enables the production of a long-fiber nonwoven fabric with excellent stretchability. From this viewpoint, a modulus of elasticity EB of 0.010 times or more and 0.400 times or less the modulus of elasticity EA' is more preferable.

[0142] The thermoplastic resin B used in this process may be of one type, but from the viewpoint of suitably controlling the elastic modulus EB, it may contain multiple types of thermoplastic resin B.

[0143] Furthermore, it is preferable to add 0.01% to 5.0% by mass of a fatty acid amide compound to the thermoplastic resin B before spinning, as this suppresses yarn breakage during the spinning process and thus stabilizes the process. The fatty acid amide compounds used are those exemplified in [Thermoplastic Resin A, Fiber FA] above. Among these, stearic acid amide and erucic acid amide are particularly preferred because they have excellent heat resistance, preventing excessive decomposition when the thermoplastic resin melts, allowing for appropriate friction on the fibers, and suppressing adhesion to the spinning equipment.

[0144] In this process, the fiber FB may be a single-component fiber mainly composed of the thermoplastic resin B, or a composite fiber made of thermoplastic resin B of different compositions.

[0145] The spinning speed, which is the speed ultimately reached by high-speed air traction when forming web B according to the present invention, is preferably 500 m / min or more, and more preferably 700 m / min or more. By setting the spinning speed to 500 m / min or more, a uniform web can be obtained, and when it becomes a long-fiber nonwoven fabric, stress distribution is achieved and good elongation is obtained. On the other hand, the spinning speed is preferably 8000 m / min or less, and more preferably 7000 m / min or less. By doing so, web B can be obtained stably without yarn breakage.

[0146] (c-3) Process for producing a laminated web This process is the same as in the (b-3) process, in which web A' and web B are laminated to obtain a laminated web. This laminated web is selected according to the purpose of use, etc., and as described above, when it becomes a long fiber nonwoven fabric, it has the following configuration, that is, a layer (O' layer) made of fibers FA' mainly composed of thermoplastic resin A' is laminated on one surface side, a long fiber nonwoven fabric layer (I layer) made of fibers FB mainly composed of thermoplastic resin B different from thermoplastic resin A' is laminated on the other surface side, an O' layer is laminated on both surfaces, and furthermore, it includes multiple long fiber nonwoven fabric layers such as an O' layer / I layer / O' layer laminated in that order. Specific lamination configurations of four or more layers not mentioned above include, for example, O' layer / I layer / I layer / O' layer, O' layer / I layer / O' layer / I layer, O' layer / I layer / O' layer / I layer / O' layer, and O' layer / I layer / I layer / I layer / O' layer. Among these, a more preferable configuration is one in which layers made of crimped fibers FA, which easily provide a smooth touch, are laminated on both the front and back surfaces of a layer made of fibers FB, which easily provides a rubbery touch, that is, a configuration in which layers are laminated in the order of O' layer / I layer / O' layer, or a configuration in which layers are laminated in the order of O' layer / I layer / O' layer / I layer / O' layer. As mentioned above, another long-fiber nonwoven fabric layer different from both the O' layer and the I layer may also be laminated.

[0147] (c-4) Step to form a fused sheet In this step, similar to step (b-4) above, the laminated sheet is pressed with a roll whose surface temperature is between TmB-50°C and TmB+70°C, where TmB is the melting point of the thermoplastic resin B, to form a fused sheet having fused and unfused portions.

[0148] The rolls used in this process are preferably configured to give the laminated sheet a regularly patterned fusion portion, and more specifically, a pair of rolls consisting of an embossing roll and a flat roll having a regularly patterned shape is preferred.

[0149] Here, an embossed roll having a regular pattern is, for example, one in which protrusions (convex parts) are formed in the parts corresponding to the fusion area, or concave shapes are formed in the parts not corresponding to the fusion area. In particular, it is preferable if there are further irregularities formed on the top of the convex parts corresponding to the fusion area, or if the top part is curved, as this makes it easier to create irregularities in the fusion area and allows for easy control of the ratio of surface roughness to thickness of the fusion area.

[0150] Furthermore, by ensuring that the spacing between adjacent fused portions is between 50 μm and 20 mm, it is possible to produce a long-fiber nonwoven fabric that has flexibility, excellent stretchability, and excellent dimensional stability, which is preferable.

[0151] Furthermore, it is preferable that the area ratio of the top portion of the convex part corresponding to the fused portion of the roll is 0.30 or less, as this allows for appropriate control of the ratio of the fused portion of the long-fiber nonwoven fabric. The area ratio of the top portion referred to here is the value obtained by rounding the ratio of the area of ​​the top portion to the area calculated from the diameter and length of the roll to the third decimal place.

[0152] Furthermore, the surface temperature of the roll is preferably set to TmB-50°C or higher and TmB+70°C or lower, where TmB (°C) is the melting point of the thermoplastic resin B. This is preferable because it allows for the creation of a long-fiber nonwoven fabric with excellent dimensional stability, and because the pressure portion of the roll maintains the shape of the thermoplastic resin A, which has a high modulus of elasticity, while the thermoplastic resin B, which has a low modulus of elasticity, deforms without maintaining its shape. This makes it easier to create irregularities in the fused portion and to control the ratio of surface roughness to thickness of the fused portion. Preferably, the surface temperature is TmB-50°C or higher and TmB+50°C or lower, more preferably TmB-50°C or higher and TmB+30°C or lower, and even more preferably TmB-50°C or higher and TmB+20°C or lower.

[0153] From the viewpoint of maintaining the elastic modulus of the thermoplastic resin A', the surface temperature is preferably TmA'-30°C or lower, and particularly preferably TmA'-40°C or lower, when TmA' (°C) is the melting point of the thermoplastic resin A'. In this case, the pressure applied by the roll is preferably such that the linear pressure of the roll is 0.5 N / cm or more and 5.0 N / cm or less. By applying pressure with such a linear pressure and forming a fused sheet, the deformation of the fiber FA' can be maintained and the ratio of surface roughness to thickness of the fused portion can be controlled.

[0154] (d) Other processes The product obtained after completing the above processes may be used as is as a long fiber nonwoven fabric, but it is also preferable to perform various post-processing steps to make it a long fiber nonwoven fabric, similar to the general method of manufacturing nonwoven fabrics. Of course, it goes without saying that a long fiber nonwoven fabric that has undergone post-processing is also treated as a long fiber nonwoven fabric in the present invention.

[0155] The long-fiber nonwoven fabric of the present invention may be stretched to improve its elasticity. This stretching may be carried out using a general stretching device that stretches the fused sheet in the width direction and / or the longitudinal direction, or a method called gear stretching described in Japanese Patent Application Publication No. 2003-73967 may be used. In this process, it is preferable to stretch the long-fiber nonwoven fabric in the width direction and / or longitudinal direction by a range of 1.5 to 5.0 times in order to obtain elasticity suitable for use as a sanitary material. By stretching the long-fiber nonwoven fabric of the present invention preferably by 1.5 times or more, more preferably by 2.0 times or more, it is possible to obtain a nonwoven fabric that has excellent elasticity and a good feel as the crimped fibers FA sag on the surface of the nonwoven fabric. On the other hand, by stretching the long-fiber nonwoven fabric of the present invention preferably by 5.0 times or less, more preferably by 4.0 times or less, it is possible to stretch it uniformly, and when used as a sanitary material, it is possible to obtain a nonwoven fabric that has no unevenness in tightness and has an excellent fit.

[0156] When stretching the long-fiber nonwoven fabric of the present invention using a gear roll, the temperature of the gear roll (stretching temperature) is preferably 10°C or higher and 150°C or lower. Setting the stretching temperature preferably to 10°C or higher, more preferably to 20°C or higher, and even more preferably to 30°C or higher, promotes deformation of the fused portion, thereby improving the uniformity of the stretching, which is preferable. On the other hand, setting the stretching temperature preferably to 150°C or lower, more preferably to 100°C or lower, suppresses adhesion to the roll during the process, allowing for stable stretching.

[0157] Furthermore, the long-fiber nonwoven fabric of the present invention can be subjected to various treatments depending on its application and purpose, such as perforation, application of various treatment agents including hydrophilic treatment, lamination with a different layer, and printing.

[0158] The hole-drilling process may result in openings that penetrate through the material in the thickness direction, or it may result in non-through holes that are only drilled in specific layers.

[0159] The application of the treatment agent may include squeezing and drying steps as needed. The method of applying the treatment agent to the long-fiber nonwoven fabric is not particularly limited and can include, for example, applying a solution in which the treatment agent is dissolved or dispersed, or immersing the fabric. Examples of treatment agents other than hydrophilic agents include antibacterial agents, antioxidants, preservatives, matting agents, pigments, rust inhibitors, fragrances, and defoaming agents.

[0160] Furthermore, when laminating the other structures onto the long-fiber nonwoven fabric of the present invention, the method of laminating (for example, bonding) each layer is not limited. For example, it can be carried out by known methods such as thermal fusion such as thermal embossing or ultrasonic fusion, mechanical entanglement such as needle punching or water jetting, or bonding with hot melt or solvent-based adhesives.

[0161] Printing methods include well-known methods such as gravure printing, mold printing, screen printing, and offset printing.

[0162] [Applications] The long-fiber nonwoven fabric of the present invention has excellent stretchability and good elasticity and feel, making it suitable for applications that fit close to the skin. For example, it can be suitably used for sanitary materials such as diapers and masks, medical materials such as adhesives and protective clothing, and clothing materials such as underwear. Among these, sanitary materials such as diapers and masks are particularly preferred.

[0163] It is preferable that the sanitary material of the present invention is composed of at least a portion of the long-fiber nonwoven fabric of the present invention or a nonwoven fabric obtained by stretching the long-fiber nonwoven fabric of the present invention. When the long-fiber nonwoven fabric of the present invention is used as a stretching material in the sanitary material, it becomes a sanitary material with excellent feel, elasticity, and fit.

[0164] The sanitary materials of this invention refer to mainly disposable items used for health-related purposes such as medical care and nursing, and specifically include disposable diapers, sanitary napkins, gauze, bandages, masks, gloves, adhesive bandages, etc., as well as their constituent parts, such as the top sheet, back sheet, and side gathers of disposable diapers. In particular, it is especially preferable to apply the materials to the side gathers of disposable diapers, the waist portion of the back sheet, and the ear portions of masks.

[0165] Next, the present invention will be specifically described based on examples. However, the present invention is not limited to these examples. Unless otherwise specified, the measurements of each physical property were performed based on the methods described above.

[0166] [Measurement Method] (1) Presence or absence of crimping (radius of curvature of crimped fiber FA) A scanning electron microscope "VHX-6000" manufactured by Keyence Corporation was used as the measuring device, and the radius of curvature of the crimped fiber FA was determined using the method described above.

[0167] (2) Elastic modulus EA of crimped fiber FA and elastic modulus EB of fiber FB. The measurement equipment used was a Raman spectrometer "inVia" manufactured by RENISHAW and an atomic force microscope (AFM) "Nano-TA2" manufactured by Anasys Instruments, and the radius of curvature of crimped fiber FA was determined using the method described above. The ratio EB / EA of the elastic modulus EB of fiber FB to the elastic modulus EA of crimped fiber FA is also shown in the table. This is the value obtained by dividing the elastic modulus EB obtained by the method described above by the elastic modulus EA and rounding to the fourth decimal place.

[0168] (3) For measuring the average single fiber diameter of crimped fibers FA and FB, a scanning electron microscope "VHX-6000" manufactured by Keyence Corporation was used, and for image analysis software, "WinROOF2015" manufactured by Mitani Corporation was used, and the average single fiber diameter of crimped fibers FA and FB was determined using the method described above.

[0169] (4) Ratio of surface roughness Ra to thickness Tb of the fused joint (Ra / Tb) A scanning electron microscope "VHX-6000" manufactured by Keyence Corporation was used to measure the thickness of the fused joint, and a laser microscope "VK-X200" manufactured by Keyence Corporation was used to measure the surface roughness. The ratio of surface roughness Ra to thickness Tb (Ra / Tb) of the fused joint was determined using the method described above. In Tables 1 and 2, "Ra / Tb" is used as an abbreviation.

[0170] (5) Elongation recovery rate was measured and calculated using the method described above, with the "TENSILON" UCT-100 manufactured by Orientec Co., Ltd. as the tensile testing machine.

[0171] (6) A scanning electron microscope "VHX-6000" manufactured by Keyence Corporation was used as the device for measuring the area ratio of the fused joint, and the area ratio of the fused joint was determined using the method described above.

[0172] (7) Elongation at break, elongation recovery rate, and apparent density after 100% elongation were measured and calculated using the method described above with the "TENSILON" UCT-100 tensile testing machine manufactured by Orientec Co., Ltd.

[0173] (8) Elongation (stretchability) The tensile testing machine used was the "TENSILON" UCT-100 manufactured by Orientec Co., Ltd., and the tensile strength was measured and calculated using the following method: (i) Five test pieces were randomly cut from the sample, each measuring 200 mm in the same direction as the direction with the lowest maximum elongation obtained in the measurement of the elongation at break described in (7) above, and 50 mm in the direction perpendicular to it. (ii) While pulling the test piece with the tensile testing machine at an initial length of 10 mm and a tensile speed of 100% / min, the pulled test piece was visually observed, and the elongation (%) at which a hole appeared in the test piece was read. (iii) The measurement described in (iii-2) above was performed on the five test pieces, the arithmetic mean was calculated, and the elongation was evaluated by rounding to the first decimal place. An elongation of 100% or more was considered acceptable.

[0174] (9) Elasticity Thirty healthy adults performed the following evaluation and assessed the elasticity on a three-point scale. The average score of the evaluation results was calculated and this value was used as the evaluation result for elasticity. <Evaluation method> (i) From the long-fiber nonwoven fabric, a test piece measuring 40 cm in the same direction as the elongation recovery rate was measured, and a test piece measuring 5 cm perpendicular to that direction was cut. (ii) The cut test piece was set to a tensile length of 30 cm and attached to a tensile testing machine (Orientec Co., Ltd. "TENSILON" "UCT-100"), and pulled to 100% elongation at a tensile speed of 100% / min in the same direction as the elongation recovery rate was measured, and then returned to 0% elongation at the same speed. (iii) The length of the arm circumference at the midpoint between the shoulder and elbow of the upper arm of each evaluator's dominant arm was measured in cm, and the value was rounded to the second decimal place to obtain the arm diameter Da (cm). (iv) The test piece treated in (ii) above is cut to a length of 0.3 × Da (cm) in the same direction as the measurement of the elongation recovery rate, and 5 cm perpendicular to it. The ends of the long sides are joined together with double-sided tape at 1 cm from each other to create a ring-shaped sample. (v) The ring-shaped sample is attached to the location where the arm diameter of each evaluator's dominant arm was measured, and the elbow is bent and straightened 20 times. (vi) The average score of the results evaluated by each evaluator was calculated in the following three stages: 5: There is no stiffness when the elbow is bent, and it follows suitably when the elbow is straightened. 3: Stiffness is felt when the elbow is bent. Or, there is no stiffness when the elbow is bent, but it does not follow well when the elbow is straightened. 1: Excessive stiffness is felt when the elbow is bent. Or, the sample does not follow at all when the elbow is straightened and slips off.

[0175] (10) Tactile sensation After measuring the stretch recovery rate, 30 healthy adults touched the test pieces with their hands and evaluated the tactile sensation on the following three scales. The average score of the evaluation results was calculated and this value was used as the evaluation result for tactile sensation. 5: When pressed with a finger, it has a fluffy bulkiness and the fibers do not catch on the finger. 3: When pressed with a finger, it has a fluffy bulkiness, but there is a feeling that the fibers catch on the finger. Or, there is no feeling that the fibers catch on the finger, but the fluffy tactile sensation is minimal. 1: When pressed with a finger, no bulkiness is felt. Or, the fibers catch on the finger due to excessive fluffiness.

[0176] [Polymers used in the Examples and Comparative Examples] PP1: Homopolypropylene with a melt viscosity of 360 Pa·s, an elastic modulus of 1600 MPa, and a melting point of 160°C PP2: Homopolypropylene with a melt viscosity of 190 Pa·s, an elastic modulus of 1500 MPa, and a melting point of 160°C PP3: Homopolypropylene with a melt viscosity of 310 Pa·s, an elastic modulus of 1500 MPa, and a melting point of 160°C PP4: Homopolypropylene with a melt viscosity of 660 Pa·s, an elastic modulus of 1600 MPa, and a melting point of 160°C PP5: Homopolypropylene with a melt viscosity of 230 Pa·s, an elastic modulus of 1500 MPa, and a melting point of 160°C PP6: Homopolypropylene with a melt viscosity of 70 Pa·s, an elastic modulus of 1500 MPa, and a melting point of 160°C PP7: A blended polymer obtained by blending PP5 at a ratio of 95 wt% and TPO1 (described below) at a ratio of 5 wt%, with a melt viscosity of 240 Pa·s, an elastic modulus of 1350 MPa, and a melting point of 160°C. PP8: Homopolypropylene with a melt viscosity of 275 Pa·s, an elastic modulus of 1500 MPa, and a melting point of 160°C. PP9: Homopolypropylene with a melt viscosity of 1370 Pa·s, an elastic modulus of 1650 MPa, and a melting point of 160°C. TPO1: A polypropylene-based elastomer with an elastic modulus of 25 MPa and a melting point of 51°C. TPO2: A styrene-based elastomer with an elastic modulus of 15 MPa and a melting point of 100°C.

[0177] [Example 1] (Process for forming web A) PP1 and PP2 were used as thermoplastic resin A. These were melted in separate extruders and spun at a spinning temperature of 230°C from a rectangular die that yielded a side-by-side composite cross section. The extrusion rate per hole was 0.55 g / (min·hole), and the extrusion mass ratio was PP1:PP2 = 50:50. After the spun yarn was cooled and solidified, it was pulled in a rectangular ejector at a spinning speed of 3200 m / min and collected on a moving collection belt with a basis weight of 10 g / m². ２ A web A (O layer, spunbond nonwoven fabric) containing crimped fibers FA was formed.

[0178] (Process for forming web B) TPO1 was used as the thermoplastic resin B, which was melted in an extruder and spun from a rectangular die at a spinning temperature of 230°C with a discharge rate of 0.2 g / min per single hole. After the spun yarn was cooled and solidified, it was pulled in a rectangular ejector at a spinning speed of 900 m / min and collected directly onto the web A on a moving collection belt, with a basis weight of 20 g / m². ２ A web B (I layer, spunbond nonwoven fabric) containing fiber FB was formed.

[0179] (Process for manufacturing a laminated web) Web A (layer O) and Web B (layer I) are laminated together, and Web A is directly collected on the Web B side of the Web A in the same manner as in the process for manufacturing Web A, thereby obtaining a laminated web in the order of Web A (layer O) / Web B (layer I) / Web A (layer O).

[0180] (Process for forming a fused sheet) An embossing roll having a pair of upper and lower heating mechanisms with the following configuration is used as the roll, and the laminated web obtained in the previous process is pressed under the following conditions to a basis weight of 40 g / m². ２ A long-fiber nonwoven fabric was obtained. • Upper roll: A metal embossed roll with square protrusions arranged in a staggered pattern at the same pitch in both the direction of net movement (MD direction) and the direction perpendicular to it (CD direction) (area ratio of protrusions: 0.11) • Lower roll: A metal flat roll with a linear pressure of 3.0 N / cm • Surface temperature: 50°C The fused portion of the obtained long-fiber nonwoven fabric had suitable irregularities for the fused portion, as shown in Figure 3, and the Ra / Tb was 0.37. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 1.

[0181] [Example 2] (Web Forming Process) Using PP1 as thermoplastic resin A and TPO1 as thermoplastic resin B, PP1 and TPO1 were melted in separate extruders and spun at a spinning temperature of 230°C from a rectangular die that yields a side-by-side composite cross section, with a discharge rate of 0.55 g / (min·hole) per hole and a discharge mass ratio of PP1:PP2 = 50:50. After the spun yarn was cooled and solidified, it was pulled in a rectangular ejector at a spinning speed of 3200 m / min and collected on a moving collection belt with a basis weight of 30 g / m². ２ I got the web.

[0182] (Process for forming a fused sheet) An embossing roll having a pair of upper and lower heating mechanisms with the following configuration is used as the roll, and the web A obtained in the previous process is pressed under the following conditions until the basis weight is 30 g / m ２ A long-fiber nonwoven fabric was obtained. • Upper roll: A metal embossed roll with square protrusions arranged in a staggered pattern at the same pitch in both the MD and CD directions (area ratio of protrusions: 0.11) • Lower roll: A metal flat roll • Linear pressure: 3.0 N / cm • Surface temperature: 50°C The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.60. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 1.

[0183] [Example 3] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that in the process of forming web B, the thermoplastic resin B was changed to a resin blended of TPO1 and TPO2 in a ratio of TPO1:TPO2 = 80:20. The melting point of the thermoplastic resin B constituting web B was 51°C. The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.45. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 1.

[0184] [Example 4] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that in the process of forming web B, the thermoplastic resin B was changed to a resin blended from TPO1 and PP1 in a ratio of TPO1:PP1 = 78:22. The melting point of the thermoplastic resin B constituting web B was 51°C. The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.55. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 1.

[0185]

[0186] [Example 5] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that PP3 was used instead of PP2 as thermoplastic resin A in the process of forming web A. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.36. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 2.

[0187] [Example 6] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that the surface temperature of the roll was changed to 105°C in the process of forming the fused sheet. The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.21. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 2.

[0188] [Example 7] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that the linear pressure of the roll was changed to 0.5 N / cm in the process of forming the fused sheet. The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.75. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 2.

[0189] [Example 8] In the process of forming web A, the basis weight of web A is set to 5 g / m ２ In the process of forming web B, the basis weight of web B was changed to 30 g / m ２ A long-fiber nonwoven fabric was obtained in the same manner as in the example, except for one change. In the fused portion of the obtained long-fiber nonwoven fabric, the Ra / Tb ratio was 0.24. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 2.

[0190] [Example 9] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that the thermoplastic resin A was changed as follows in the process of forming web A. PP1: Changed to a resin blended of PP1 and carbon-22 erucic acid amide in a ratio of PP1:erucic acid amide = 96:4. PP2: Changed to a resin blended of PP2 and the aforementioned erucic acid amide in a ratio of PP2:erucic acid amide = 96:4. The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.36. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 2.

[0191] [Example 10] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that the linear pressure of the roll was changed to 1.0 N / cm in the process of forming the fused sheet. The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.69. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 2.

[0192] [Example 11] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that the linear pressure of the roll was changed to 4.0 N / cm in the process of forming the fused sheet. The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.31. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 2.

[0193]

[0194] [Comparative Example 1] In the process of forming web A, only PP1 was used as the thermoplastic resin A, melted in a single extruder, and extruded at a discharge rate of 0.55 g / (min・hole), except that the procedure was the same as in Example 1. The properties of the fibers made of thermoplastic resin A in the obtained long fiber nonwoven fabric were such that the radius of curvature was 2500 μm and there was no crimp. In addition, the Ra / Tb in the fused portion of the obtained long fiber nonwoven fabric was 0.38. The physical properties and evaluation results of the obtained long fiber nonwoven fabric are shown in Table 3.

[0195] [Comparative Example 2] In the process of forming the fused sheet, the pressure was applied under the same conditions as in Example 1, except that the linear pressure of the roll was set to 5.5 N / cm, resulting in a basis weight of 40 g / m². ２ A long-fiber nonwoven fabric was obtained. The fused portion of the obtained long-fiber nonwoven fabric was flat, as shown in Figure 2, and the Ra / Tb ratio was 0.15. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 3.

[0196] [Comparative Example 3] In the process of forming the fused sheet, the pressure was applied under the same conditions as in Example 1, except that the linear pressure of the roll was set to 0.1 N / cm, resulting in a basis weight of 40 g / m². ２ A long-fiber nonwoven fabric was obtained. The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.85. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 3.

[0197] [Comparative Example 4] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that in the process of forming web B, the thermoplastic resin B was changed to a resin blended from TPO1 and PP1 in a ratio of TPO1:PP1 = 60:40. The melting point of the thermoplastic resin B constituting web B was 160°C. The Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.82. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 3.

[0198] [Comparative Example 5] A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that the surface temperature of the roll was changed to 125°C in the process of forming the fused sheet. The fused portion of the obtained long-fiber nonwoven fabric was flat as shown in Figure 2, and the Ra / Tb was 0.16. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 3.

[0199]

[0200] As shown in Tables 1 and 2, the long-fiber nonwoven fabrics of Examples 1 to 11 exhibited high elongation and elasticity, as well as excellent tactile properties. In particular, Examples 1, 3, and 7 to 9 showed extremely excellent elongation.

[0201] On the other hand, in the case of the long-fiber nonwoven fabric of Comparative Example 1, the fibers made of thermoplastic resin A did not have crimp, and when stretched, the fibers became stiff, resulting in poor stretchability. Furthermore, because the fibers were prone to stiffness, the elasticity was also poor. In addition, the tactile feel after stretching was poor because the fibers made of thermoplastic resin A became excessively loose.

[0202] In the case of the long-fiber nonwoven fabric of Comparative Example 2, the linear pressure of the roll was too high, causing even the crimped fibers FA to deform significantly and the fused portion to become flat. As a result, the Ra / Tb of the fused portion was too low, making it difficult to deform and resulting in poor stretchability. Furthermore, as a result of uneven load distribution during stretching, the elasticity after stretching was somewhat inferior.

[0203] In the case of the long-fiber nonwoven fabric of Comparative Example 3, the Ra / Tb ratio of the fused portion was too high, resulting in uneven stress distribution in some of the fused portions and poor stretchability. On the other hand, the deformation of the fused portion under stress was large, resulting in good elasticity.

[0204] The long-fiber nonwoven fabric of Comparative Example 4 had a low elongation recovery rate and poor elasticity.

[0205] In Comparative Example 5, the long-fiber nonwoven fabric was subjected to excessive deformation of the crimped fibers FA due to the high surface temperature of the roll, resulting in a flattened fusion joint. Furthermore, the Ra / Tb ratio of the fusion joint was too low, making it difficult to deform and resulting in poor stretchability. Consequently, it also exhibited poor elasticity.

[0206] [Examples 12-21, Comparative Examples 6-9] Examples 12 onwards and Comparative Examples 6 onwards relate to long-fiber nonwoven fabrics in which web A' and web B are laminated using core-sheath cross-section fibers, and the present invention will be specifically explained based on these examples. However, the present invention is not limited to these examples. In addition, unless otherwise specified, the measurements of each physical property were performed based on the methods described above.

[0207] [Measurement Method] (1) Molecular orientation parameters OC, OS, OC-OS in the fiber axis direction The measurement equipment used was a Raman spectrometer "inVia" manufactured by RENISHAW and an atomic force microscope (AFM) "Nano-TA2" manufactured by Anasys Instruments, and the molecular orientation parameters OC, OS, and their difference in the fiber axis direction were determined using the method described above.

[0208] (2) Elastic modulus EA of fiber FA' and elastic modulus EB of fiber FB. The measuring devices used were a Raman spectrometer "inVia" manufactured by RENISHAW and an atomic force microscope (AFM) "Nano-TA2" manufactured by Anasys Instruments, and the elastic modulus of each fiber was determined using the method described above. The ratio EB / EA' of the elastic modulus EB of fiber FB to the elastic modulus EA' of fiber FA' is also shown in the table. This is the value obtained by dividing the elastic modulus EB obtained by the method described above by the elastic modulus EA' and rounding to the fourth decimal place.

[0209] (3) For measuring the average single fiber diameter of fibers FA' and FB, a scanning electron microscope "VHX-6000" manufactured by Keyence Corporation was used, and for image analysis software, "WinROOF2015" manufactured by Mitani Corporation was used, and the average single fiber diameter of fibers FA' and FB was determined using the method described above.

[0210] (4) For measuring the area ratio of the sheath component in the cross-section of fiber FA', a scanning electron microscope "VHX-6000" manufactured by Keyence Corporation was used, and for image analysis software, "WinROOF2015" manufactured by Mitani Corporation was used, and the area ratio of the sheath component in the cross-section of fiber FA' was determined using the method described above.

[0211] (5) Ratio of surface roughness Ra to thickness Tb of the fused portion (Ra / Tb) This was determined by the same method as in Examples 1 to 11.

[0212] (6) The elongation recovery rate was determined by the same method as in Examples 1 to 11.

[0213] (7) The area ratio of the fused portion was determined by the same method as in Examples 1 to 11.

[0214] (8) Breaking elongation, elongation recovery rate, and apparent density after 100% stretching were determined by the same method as in Examples 1 to 11.

[0215] (9) Elongation (stretch) This was determined by the same method as in Examples 1 to 11.

[0216] (10) Elasticity was determined by the same method as in Examples 1 to 11.

[0217] (11) Tactile sensation was determined by the same method as in Examples 1 to 11.

[0218] [Example 12] (Process for forming web A') PP4 was used as the core component and PP5 as the sheath component. These were melted in separate extruders and spun at a spinning temperature of 230°C from a rectangular die that yielded a concentric core-sheath composite cross section. The extrusion rate per hole was 0.55 g / (min·hole), and the extrusion mass ratio was PP4:PP5 = 40:60. After the spun yarn was cooled and solidified, it was pulled in a rectangular ejector at a spinning speed of 3200 m / min and collected on a moving collection belt with a basis weight of 10 g / m². ２ A web A' (O' layer, spunbond nonwoven fabric) containing fiber FA' was formed.

[0219] (Process for forming web B) TPO1 was used as the thermoplastic resin B, which was melted in an extruder and spun from a rectangular die at a spinning temperature of 230°C with a discharge rate of 0.2 g / min per single hole. After the spun yarn was cooled and solidified, it was pulled in a rectangular ejector at a spinning speed of 900 m / min and collected directly onto the web A on a moving collection belt, with a basis weight of 20 g / m². ２ A web B (I layer, spunbond nonwoven fabric) containing fiber FB was formed.

[0220] (Process for manufacturing a laminated web) Web A' (O' layer) and Web B (I layer) are laminated together, and Web A' is directly collected on the Web B side of the Web A' in the same manner as in the process for manufacturing Web A', thereby obtaining a laminated web in the order of Web A' (O' layer) / Web B (I layer) / Web A' (O' layer).

[0221] (Process for forming a fused sheet) An embossing roll having a pair of upper and lower heating mechanisms with the following configuration is used as the roll, and the laminated web obtained in the previous process is pressed under the following conditions to a basis weight of 40 g / m². ２ A long-fiber nonwoven fabric was obtained. • Upper roll: A metal embossed roll with square protrusions arranged in a staggered pattern at the same pitch in both the direction of net movement (MD direction) and the direction perpendicular to it (CD direction) (area ratio of protrusions: 0.11) • Lower roll: A metal flat roll with a linear pressure of 3.0 N / cm • Surface temperature: 50°C The fused portion of the obtained long-fiber nonwoven fabric had suitable irregularities for the fused portion, as shown in Figure 3, and the Ra / Tb was 0.37. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 4.

[0222] [Example 13] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that in the process of forming web A', the extrusion mass ratio was set to PP4:PP5 = 15:85. In the fused portion of the obtained long-fiber nonwoven fabric, the Ra / Tb ratio was 0.36. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 4.

[0223] [Example 14] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that in the process of forming web A', the extrusion mass ratio was set to PP4:PP5 = 50:50 during spinning. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.37. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 4.

[0224] [Example 15] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that PP1 was used instead of PP4 as the core component in the process of forming web A'. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.37. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 4.

[0225]

[0226] [Example 16] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that PP2 was used instead of PP5 as the sheath component in the process of forming web A'. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.40. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 5.

[0227] [Example 17] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that PP6 was used instead of PP5 as the sheath component in the process of forming web A'. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.31. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 5.

[0228] [Example 18] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that the spinning speed was 4000 m / min in the process of forming web A'. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.43. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 5.

[0229] [Example 19] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that the spinning speed was 2200 m / min in the process of forming web A'. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.29. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 5.

[0230] [Example 20] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that PP7 was used instead of PP5 as the sheath component in the process of forming web A'. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.29. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 5.

[0231] [Example 21] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that a rectangular die was used in the process of forming web A' to obtain an eccentric core-sheath type composite cross section. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.36. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 5.

[0232]

[0233] [Comparative Example 6] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that in the process of forming web A', the extrusion mass ratio was set to PP4:PP5 = 10:90. In the fused portion of the obtained long-fiber nonwoven fabric, the Ra / Tb was 0.37. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 6.

[0234] [Comparative Example 7] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that PP8 was used instead of PP5 as the sheath component in the process of forming web A'. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.36. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 6.

[0235] [Comparative Example 8] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that PP9 was used instead of PP5 as the sheath component in the process of forming web A'. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.45. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 6.

[0236] [Comparative Example 9] A long-fiber nonwoven fabric was obtained in the same manner as in Example 12, except that the spinning speed was 1800 m / min in the process of forming web A'. In addition, the Ra / Tb ratio in the fused portion of the obtained long-fiber nonwoven fabric was 0.26. The physical properties and evaluation results of the obtained long-fiber nonwoven fabric are shown in Table 6.

[0237]

[0238] As shown in Tables 4 and 5, the long-fiber nonwoven fabrics of Examples 12 to 21 exhibited high elongation and elasticity, as well as excellent tactile properties. In particular, Examples 12, 13, 16 to 18, and 20 to 21 showed extremely excellent elongation.

[0239] On the other hand, in the case of the long-fiber nonwoven fabrics of Comparative Examples 6, 7, and 9, the difference in orientation parameters OC-OS between the core component and the sheath component was small, making it difficult for the fibers FA' to stretch. As a result, the fibers became stiff during stretching, and their stretchability was poor. Furthermore, the tendency for the fibers to stiffen also resulted in poor elasticity. In addition, because the fibers were stretched unevenly due to their stiffness, the slack of the fibers FA' after stretching was also uneven, resulting in a poor tactile feel.

[0240] In the long-fiber nonwoven fabric of Comparative Example 8, the difference in orientation parameters OC-OS between the core component and the sheath component was excessively high, resulting in high rigidity of the fiber FA', making it extremely difficult to stretch and thus poor in elongation. Furthermore, due to the high rigidity of the fiber FA', the fused joints broke after stretching, resulting in poor elasticity.

[0241] 1-A: Inner contour of the curved shape of the crimped fiber FA 1-B: Outer contour of the curved shape of the crimped fiber FA A2, A3, A4: Fused parts

Claims

1. A long-fiber nonwoven fabric containing crimped fibers FA, wherein the long-fiber nonwoven fabric has fused portions and non-fused portions, the ratio of the surface roughness Ra of the fused portion to the thickness Tb of the fused portion (Ra / Tb) is 0.20 or more and 0.80 or less, and the elongation recovery rate of the long-fiber nonwoven fabric is 50% or more and 99% or less.

2. A long-fiber nonwoven fabric containing fiber FA', wherein the long-fiber nonwoven fabric has a fused portion and a non-fused portion, the ratio of the surface roughness Ra of the fused portion to the thickness Tb of the fused portion (Ra / Tb) is 0.20 or more and 0.80 or less, the elongation recovery rate of the long-fiber nonwoven fabric is 50% or more and 99% or less, and the fiber FA' satisfies the following (a) and (b): (a) It has a core-sheath composite cross section; (b) The difference (OC-OS) between the molecular orientation parameter OC in the fiber axis direction in the core component and the molecular orientation parameter OS in the fiber axis direction in the sheath component is 1.5 or more and 5.0 or less.

3. The long-fiber nonwoven fabric according to claim 1 or claim 2, comprising: crimped fibers FA mainly composed of thermoplastic resin A or fibers FA' mainly composed of thermoplastic resin A'; and fibers FB mainly composed of thermoplastic resin B different from the thermoplastic resin A or thermoplastic resin A'.

4. The long-fiber nonwoven fabric according to claim 3, wherein the ratio of crimped fibers FA or fibers FA' on at least one surface of the long-fiber nonwoven fabric is 50% or more.

5. The long-fiber nonwoven fabric according to claim 3, wherein the modulus of elasticity EB of the fiber FB is 0.005 times or more and 0.400 times or less of the modulus of elasticity EA of the crimped fiber FA or the modulus of elasticity EA' of the fiber FA'.

6. The long-fiber nonwoven fabric according to claim 3, wherein 80.0% by mass or more and 100.0% by mass of the thermoplastic resin B is one or more selected from the group consisting of polyolefin elastomers, styrene elastomers, polyurethane elastomers, amide elastomers, and polyester elastomers.

7. The apparent density of the long-fiber nonwoven fabric after 100% stretching is 0.020 g / cm³. ３ 0.200g / cm or more ３ The following is the long-fiber nonwoven fabric according to claim 1 or claim 2.

8. A laminate comprising a long-fiber nonwoven fabric according to claim 1 or claim 2, and a layer different from the long-fiber nonwoven fabric.

9. A sanitary material comprising at least a portion of the long-fiber nonwoven fabric described in claim 1 or claim 2.

10. A method for producing a long-fiber nonwoven fabric according to claim 1, comprising the steps of: extruding a polymer stream containing thermoplastic resin A and thermoplastic resin B different from thermoplastic resin A from a spinneret to form a web; and pressurizing the web with a roll having a surface temperature of TmB-50°C or higher and TmB+70°C or lower, where TmB (°C) is the melting point of thermoplastic resin B, to form a fused sheet having fused portions and non-fused portions.

11. A method for producing a long-fiber nonwoven fabric according to claim 3, comprising: a step of forming a web A containing crimped fibers FA mainly composed of thermoplastic resin A; a step of forming a web B containing fibers FB mainly composed of thermoplastic resin B different from thermoplastic resin A; a step of producing a laminated web by laminating web A and web B; and a step of forming a fused sheet having fused portions and non-fused portions by pressurizing the laminated web with a roll having a surface temperature of TmB-50°C or more and TmB+70°C or less, where TmB (°C) is the melting point of thermoplastic resin B.

12. A method for producing a long-fiber nonwoven fabric according to claim 3, comprising the steps of: forming a web A' containing fibers FA' mainly composed of thermoplastic resin A'; forming a web B containing fibers FB mainly composed of thermoplastic resin B different from the thermoplastic resin A'; producing a laminated web by laminating the web A' and the web B; and forming a fused sheet having fused portions and non-fused portions by pressurizing the laminated web with a roll having a surface temperature of TmB-50°C or more and TmB+70°C or less, where TmB (°C) is the melting point of the thermoplastic resin B.

13. A method for producing a long-fiber nonwoven fabric according to any one of claims 10 to 12, wherein in the step of forming the fused sheet, the linear pressure of the roll is 0.5 N / cm or more and 5.0 N / cm or less.

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