Long-fiber nonwoven fabric laminate, fiber product, diaper, and production method for long-fiber nonwoven fabric laminate

Abstract

A long-fiber nonwoven fabric laminate according to the present disclosure comprises at least two spunbond nonwoven fabric layers and at least one meltblown nonwoven fabric layer. The spunbond nonwoven fabric layers are disposed on both surface layers of the long-fiber nonwoven fabric laminate. The basis weight of the meltblown nonwoven fabric layer is 0.5 g / m2 to 1.0 g / m2. The basis weight of the long-fiber nonwoven fabric laminate is 3.0 g / m2 to 10.0 g / m2. The percentage of thickness of fused embossed portions is 19.0% to 35.0%.

Description

Laminates of long fibers, textile products, diapers, and methods for manufacturing laminates of long fibers

[0001] This disclosure relates to a long-fiber nonwoven laminate, textile products, diapers, and a method for manufacturing a long-fiber nonwoven laminate.

[0002] Nonwoven fabrics are widely used in various applications due to their excellent breathability and flexibility. In recent years, multi-layering of nonwoven fabrics has been practiced with the aim of giving them various functions and properties.

[0003] Patent Document 1 discloses a multilayer nonwoven fabric (hereinafter also referred to as a "long fiber nonwoven laminate"). In this long fiber nonwoven laminate, the two outermost layers are spunbond nonwoven layers, and at least one inner layer is a meltblown nonwoven layer. The resin forming the spunbond nonwoven layer has a specific melting endotherm ΔH.

[0004] Patent Document 1: International Publication No. 2014 / 042253

[0005] In recent years, from the perspective of cost competition and other factors, the basis weight of long-fiber nonwoven laminates has been reduced (for example, 10 g / m²). ２ The following are required. In addition, especially in applications for sanitary materials (e.g., diapers and sanitary napkins), long-fiber nonwoven laminates are required to have excellent water pressure resistance per basis weight of the meltblown nonwoven layer and low bending stiffness (i.e., low rigidity). Low bending stiffness results in long-fiber nonwoven laminates that are soft and conform well to uneven surfaces. A larger basis weight of the meltblown nonwoven layer tends to result in higher water pressure resistance. On the other hand, the fiber diameter of the meltblown nonwoven layer is finer than that of the spunbond nonwoven layer. The fiber density of the meltblown nonwoven layer is higher than that of the spunbond nonwoven layer. If such a meltblown nonwoven layer is included in larger quantities in the intermediate layer, it tends to result in a stiff long-fiber nonwoven laminate (e.g., a hard-feeling long-fiber nonwoven laminate).

[0006] In long-fiber nonwoven fabric laminates, various studies have been conducted to achieve a balance between water pressure resistance and bending rigidity. However, in the manufacturing process of low-basis-weight long-fiber nonwoven fabric laminates, when the temperature of the embossing roll in the heat fusion treatment is increased, a highly rigid long-fiber nonwoven fabric laminate is easily obtained, which tends to impair the soft fluffiness of the long-fiber nonwoven fabric laminate. When the basis weight of the meltblown nonwoven fabric layer is low, the water pressure resistance tends to decrease. Under these circumstances, there is a demand for further reduction in basis weight while maintaining the balance between water pressure resistance and bending rigidity.

[0007] In the long-fiber nonwoven fabric laminate which is a multilayer nonwoven fabric having a meltblown nonwoven fabric layer and a spunbond nonwoven fabric layer disclosed in Patent Document 1, the water pressure resistance per basis weight of the meltblown nonwoven fabric layer may not be sufficient.

[0008] Embodiments of the present disclosure have been made in view of the above. An object of the present invention is to provide a long-fiber nonwoven fabric laminate, a fiber product, a diaper, and a method for producing a long-fiber nonwoven fabric laminate, wherein the long-fiber nonwoven fabric laminate and the meltblown nonwoven fabric layer have a low basis weight, while the long-fiber nonwoven fabric laminate is excellent in water pressure resistance per basis weight of the meltblown nonwoven fabric layer and has low bending rigidity.

[0009] Means for solving the above problem include the following embodiments. <1> A long-fiber nonwoven fabric laminate comprising at least two spunbond nonwoven fabric layers and at least one meltblown nonwoven fabric layer, wherein the spunbond nonwoven fabric layers are disposed on both surface layers of the long-fiber nonwoven fabric laminate, and the basis weight of the meltblown nonwoven fabric layer is 0.5 g / m ２ to 1.0 g / m ２ , and the basis weight of the long-fiber nonwoven fabric laminate is 3.0 g / m ２ to 10.0 g / m ２, which is a long-fiber nonwoven fabric laminate, wherein a thickness ratio of an embossed fused portion of the long-fiber nonwoven fabric laminate is 19.0% to 35.0%. <2> The long-fiber nonwoven fabric laminate according to <1>, wherein a ratio of a basis weight of the melt-blown nonwoven fabric layer to a basis weight of the long-fiber nonwoven fabric laminate is 6.0% or more and less than 20.0%. <3> The long-fiber nonwoven fabric laminate according to <1> or <2>, wherein an effective embossed area ratio of the long-fiber nonwoven fabric laminate is 40.0% or more and 85.0% or less. <4> The long-fiber nonwoven fabric laminate according to any one of <1> to <3>, wherein an average fiber diameter of fibers contained in the melt-blown nonwoven fabric layer is 0.5 μm to 5.0 μm. <5> The long-fiber nonwoven fabric laminate according to any one of <1> to <4>, wherein the thermoplastic resin composition constituting the spunbond nonwoven fabric layer and the thermoplastic resin composition constituting the melt-blown nonwoven fabric layer each contain a propylene-based polymer as a main component. <6> A fiber product comprising the long-fiber nonwoven fabric laminate according to any one of <1> to <5>. <7> A diaper comprising the long-fiber nonwoven fabric laminate according to any one of <1> to <5>. <8> A method for producing a long-fiber nonwoven fabric laminate, comprising: preparing a web laminate having at least two layers of spunbond webs and at least one layer of meltblown web, wherein the spunbond webs are arranged on both surface layers; and heat-fusing the spunbond web and the meltblown web contained in the web laminate by embossing, wherein in the heat-fusing, an embossing speed is 530 m / min to 800 m / min, an embossing temperature is 140°C to 150°C, and an embossing linear pressure is 75 N / mm to 100 N / mm.

[0010] According to an embodiment of the present disclosure, there are provided a long-fiber nonwoven fabric laminate and a method for producing the same, wherein the long-fiber nonwoven fabric laminate and the melt-blown nonwoven fabric layer have a low basis weight, and are excellent in water pressure resistance per basis weight of the melt-blown nonwoven fabric layer and have low flexural rigidity.

[0011] FIG. 1 is a scanning electron microscope (SEM) image of a cross-section of an embossed fusion-bonded portion of a long-fiber nonwoven fabric laminate according to an embodiment. FIG. 2 is an SEM image of an embossed fusion-bonded portion on a surface of the long-fiber nonwoven fabric laminate according to an embodiment. FIG. 3 is an SEM image of an example of an embossed fusion-bonded portion on a surface of a long-fiber nonwoven fabric laminate of a comparative example.

[0012] In the present disclosure, the symbol "~" indicating a numerical range is used to mean that the numerical values described before and after it are included as the lower limit and the upper limit. In the numerical ranges described stepwise in the present disclosure, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of a numerical range described in another step. In the numerical ranges described in the present disclosure, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples. In the present disclosure, the term "process" includes not only an independent process, but also a case that cannot be clearly distinguished from other processes, as long as the intended object of the process is achieved. In the present disclosure, when referring to the amount of each component in a composition, if there are a plurality of substances corresponding to each component in the composition, it means the total amount of the plurality of substances present in the composition, unless otherwise specified.

[0013] (1) Long-fiber nonwoven fabric laminate The long-fiber nonwoven fabric laminate of the present disclosure (hereinafter, also simply referred to as "long-fiber nonwoven fabric laminate") comprises at least two spunbond nonwoven fabric layers and at least one meltblown nonwoven fabric layer. The spunbond nonwoven fabric layers are disposed on both surface layers of the long-fiber nonwoven fabric laminate. The basis weight of the meltblown nonwoven fabric layer is 0.5 g / m ２ to 1.0 g / m ２ . The basis weight of the long-fiber nonwoven fabric laminate (hereinafter, also referred to as "total basis weight") is 3.0 g / m ２ to 10.0 g / m ２ or less. The thickness ratio of the embossed fusion-bonded portion is 19.0% to 35.0%.

[0014] "Long fiber nonwoven laminate" refers to a nonwoven laminate mainly composed of long fibers. Specifically, the proportion of long fibers to the total amount of the nonwoven laminate is 80% to 100% by mass, and may be 90% to 100% by mass. "Spunbond nonwoven layer" refers to a layer mainly composed of spunbond nonwoven fabric. Specifically, the proportion of spunbond nonwoven fabric to the total amount of the spunbond nonwoven layer is 80% to 100% by mass, and may be 90% to 100% by mass. "Meltblown nonwoven layer" refers to a layer mainly composed of meltblown nonwoven fabric. Specifically, the proportion of meltblown nonwoven fabric to the total amount of the meltblown nonwoven layer is 80% to 100% by mass, and may be 90% to 100% by mass. "Nonwoven fabric" refers to a planar fiber aggregate in which a predetermined level of structural strength is obtained by at least one of physical and chemical methods, excluding weaving, knitting, and papermaking. "Spunbond nonwoven fabric" refers to a nonwoven fabric made by bonding a spunbond web with at least one bonding method (e.g., embossing). "Spunbond web" refers to a web made by spunbond lamination. "Spunbond lamination" refers to a method of creating a web by extruding a molten or dissolved polymer from a nozzle and laminating the resulting long fibers onto a moving screen. The average fiber diameter of spunbond nonwoven fabric is usually 5 μm or more. "Meltblown nonwoven fabric" refers to a nonwoven fabric made by bonding a meltblown web with at least one bonding method (e.g., embossing). "Meltblown web" refers to a web made by meltblown lamination. "Meltblown lamination" refers to a method of creating a web by extruding a molten polymer into a high-speed, high-temperature gas stream and laminating the resulting long fibers onto a moving screen. The average fiber diameter of meltblown nonwovens is usually less than 5 μm. The mechanical direction (hereinafter also referred to as "MD") of spunbond nonwovens and meltblown nonwovens (hereinafter also referred to as "spunbond nonwovens, etc.") can be determined by measuring the tensile strength of the spunbond nonwovens, etc. Generally, in the manufacture of spunbond nonwovens, etc., the screen movement speed is set to a fast speed from the viewpoint of productivity.Therefore, the long fibers contained in the web tend to be oriented in a direction parallel to the MD when laminated on the screen. As a result, the tensile strength of the MD in spunbond nonwovens, etc., is higher than the tensile strength in the direction perpendicular to the MD (hereinafter also referred to as "CD"). For this reason, the MD can be determined from the spunbond nonwoven itself by measuring its tensile strength.

[0015] The "thickness ratio of the embossed fused area (%)" quantitatively represents the degree of heat fusion (also called "thermocompression bonding") in the thickness direction of the long-fiber nonwoven fabric laminate during embossing. Specifically, the thickness ratio of the embossed fused area indicates the ratio of the thickness of the embossed fused area of ​​the long-fiber nonwoven fabric laminate to the thickness of the non-embossed area (areas other than the embossed fused area). For example, a small thickness ratio of the embossed fused area indicates strong heat compression bonding due to embossing. When heat compression bonding due to embossing is strong, when the surface of the long-fiber nonwoven fabric laminate is viewed, some of the fibers in the embossed fused area melt, and the molten resin fills the grooves between the fibers, forming a film. In addition, the smaller the thickness ratio of the embossed fused area (the stronger the heat fusion), the closer the film-like shape of the embossed fused area is to the shape of the embossed mark. On the other hand, if the heat-sealing due to embossing is not too strong, as shown in Figure 1, although some of the fibers melt, the molten resin does not completely fill the gaps between the fibers, and the fiber shape can be visually confirmed to remain. Here, the "embossed fused area" includes fused areas where some of multiple fibers are heat-fused and fused areas that are not fibrous (film-like areas). Specifically, the embossed fused area located on the surface of the long-fiber nonwoven fabric laminate has a total area of ​​0.1 mm² of two fused areas. ２ The above indicates the area. Whether or not an embossed fused area exists can be determined by observing the surface or cross-section of the fiber aggregate. If the embossed fused area (i.e., the area of ​​the fused area is 0.1 mm²) is present... ２ This is done depending on whether or not there are parts that are greater than or equal to the above. The method for measuring the thickness ratio of the embossed fusion part is the same as the method described in the examples.

[0016] Because the long-fiber nonwoven laminate of this disclosure has the above configuration, the meltblown nonwoven layer has a low basis weight (for example, 1.0 g / m²). ２ The following conditions apply, and the long-fiber nonwoven fabric laminate also has a low basis weight (for example, 10 g / m²). ２ Despite the following, the meltblown nonwoven fabric layer exhibits excellent water pressure resistance per basis weight and low bending rigidity. This effect is presumed to be due to, but is not limited to, the following reasons. In this disclosure, the long-fiber nonwoven laminate comprises a spunbond nonwoven fabric layer having an embossed fused portion on the surface and a low-basis-weight meltblown nonwoven fabric layer in the intermediate layer, and the thickness ratio of the embossed fused portion is relatively low. Keeping the thickness ratio of the embossed fused portion in a relatively small range means that the spunbond nonwoven fabric layer on the surface has relatively high rigidity due to the embossed fused portion. When the meltblown nonwoven fabric layer has a low basis weight, the fibers contained in the meltblown nonwoven fabric layer are generally prone to breaking due to embossing. Therefore, it is presumed that by placing such a spunbond nonwoven fabric layer on the surface of a long-fiber nonwoven fabric laminate and reinforcing the meltblown nonwoven fabric layer, the long-fiber nonwoven fabric laminate will be more likely to exhibit the effects of the present disclosure, even if the basis weight of the long-fiber nonwoven fabric laminate itself is low and the basis weight of the meltblown nonwoven fabric layer is also low. From the viewpoint of the manufacturing method, the manufacturing method of the long-fiber nonwoven fabric laminate of the present disclosure differs from the conventional manufacturing method that uses weak embossing. Specifically, in the conventional manufacturing method that uses weak embossing, the embossing temperature is set to a temperature lower than the melting point of the resin constituting the fibers (for example, embossing temperature: 100°C or less) in order to minimize the thermal history applied to the surface spunbond nonwoven fabric layer and the intermediate meltblown nonwoven fabric layer. On the other hand, in the manufacturing method of the present disclosure, a relatively high embossing temperature is set for the surface spunbond nonwoven fabric layer, and the embossing is performed over a longer period of time than in the conventional method. This results in a new long-fiber nonwoven laminate that increases the surface rigidity of the spunbond nonwoven layer while having low bending rigidity. It has been found that a long-fiber nonwoven laminate with this configuration improves the water pressure resistance per basis weight of the meltblown nonwoven layer and also exhibits low bending rigidity.

[0017] The long-fiber nonwoven fabric laminate has multiple embossed fused portions. The multiple embossed fused portions may be formed in a regular arrangement or in an irregular arrangement. The ratio of the total area of ​​the embossed fused portions to the surface area of ​​the long-fiber nonwoven fabric laminate (hereinafter referred to as the "formation ratio of embossed fused portions") is not particularly limited and may be 5% to 30% or 10% to 20%. The "formation ratio of embossed fused portions" is determined by taking a 10 mm x 10 mm test piece from the long-fiber nonwoven fabric laminate, observing the contact surface of the test piece with the embossing roll using an electron microscope (magnification: 100x), and indicating the ratio of the total area of ​​the multiple embossed fused portions to the area of ​​the long-fiber nonwoven fabric laminate observed.

[0018] The shape of the embossed fused area can be a circle, ellipse, oblong, square, rhombus, rectangle, square, or a continuous shape based on these shapes. The embossed fused area is formed by transferring the embossed mark from the embossing roll. The outer shape of the embossed fused area may be a notched shape compared to the outer shape of the embossed mark from the embossing roll.

[0019] The thickness ratio of the embossed fused portion in the long-fiber nonwoven laminate is between 19.0% and 35.0%. When the thickness ratio of the embossed fused portion exceeds 35.0%, the water pressure resistance tends to decrease. This is presumed to be because the protection of the meltblown nonwoven layer by the surface spunbond nonwoven layer is insufficient. When the thickness ratio of the embossed fused portion is less than 19.0%, water tends to leak from localized areas of the long-fiber nonwoven laminate (e.g., the periphery of the embossed fused portion), resulting in low water pressure resistance. This water leakage is presumed to be because, when the thickness ratio of the embossed fused portion is low, water pressure tends to concentrate at the periphery of the embossed fused portion. Furthermore, when the thickness ratio of the embossed fused portion falls below 13.0%, the bending rigidity of the long-fiber nonwoven laminate tends to be inferior. The thickness ratio of the embossed fused portion is preferably 20.0% to 35.0%, more preferably 21.0% to 35.0%, and even more preferably 21.0% to 32.0%, from the viewpoint of improving the water pressure resistance per basis weight of the meltblown nonwoven fabric layer of the long-fiber nonwoven laminate. The thickness ratio of the embossed fused portion may be 19.0% to 32.0%, 20.0% to 32.0%, or 21.0% to 31.0%. The thickness ratio of the embossed fused portion is determined by adjusting the embossing speed, embossing temperature, embossing linear pressure, the relationship between the melting points of the resin compositions of each layer, the basis weight of the long-fiber nonwoven laminate, and the basis weight ratio of the meltblown nonwoven fabric layer, as described later.

[0020] The effective embossed area ratio of the long-fiber nonwoven laminate is not particularly limited, but is preferably 40.0% or more and 85.0% or less, and more preferably 40.0% or more and less than 80.0%. By having an effective embossed area ratio of 40.0% or more and 85.0% or less, the long-fiber nonwoven laminate of this disclosure tends to have superior water pressure resistance per basis weight of the meltblown nonwoven and low bending stiffness.

[0021] The "effective embossed area ratio" quantitatively represents the degree of thermocompression bonding on the surface of a long-fiber nonwoven fabric laminate during embossing. Specifically, the effective embossed area ratio indicates the ratio of the area of ​​the embossed fused portion of the long-fiber nonwoven fabric laminate to the area of ​​the embossed mark. An effective embossed area ratio of over 85% means that the thermocompression bonding due to embossing is strong, and that the film-like shape of the embossed fused portion is closer to the shape of the embossed mark (i.e., the shape of the embossed fused portion and the shape of the embossed mark are roughly the same). An effective embossed area ratio of 40% to 85% indicates, as shown in Figure 2, a state in which the molten fiber material is not so abundant that it fills the gaps between adjacent fibers, and the fused state retains some of the fiber shape. The method for measuring the effective embossed area ratio is the same as the method described in the examples.

[0022] The effective embossed area ratio is preferably 50.0% to 80.0%, more preferably 60.0% to 80.0%, even more preferably 65.0% to 80.0%, and even more preferably 65.0% to 75.0%, from the viewpoint of improving the water pressure resistance per basis weight of the meltblown nonwoven fabric of the long-fiber nonwoven laminate and further lowering the bending stiffness. The effective embossed area ratio is adjusted by controlling the embossing speed, embossing temperature, embossing linear pressure, the relationship between the melting points of the resin compositions of each layer, the basis weight of the long-fiber nonwoven laminate, and the basis weight ratio of the meltblown layer, as described later.

[0023] By setting the thickness ratio of the embossed fused portion of the long-fiber nonwoven laminate to 19.0% to 35.0% and the effective embossed area ratio to 40.0% to 85.0%, both the water pressure resistance (absolute value) and the water pressure resistance per basis weight of the meltblown nonwoven fabric can be improved, and a long-fiber nonwoven laminate with superior bending rigidity can be obtained. This effect is presumed to be due to the following reasons, but is not limited to these: If the effective embossed area ratio is 85.0% or less, water leakage from local areas of the long-fiber nonwoven laminate (e.g., the edges of the embossed fused portion) can be suppressed. This is presumed to be because if the effective embossed area ratio exceeds 85.0%, water pressure tends to concentrate at the edges of the embossed fused portion. If the effective embossed area ratio is 40% or more, the desired water pressure resistance can be obtained. This is presumed to be because if the effective embossed area ratio is 40% or more, the rigidity of the surface spunbond layer increases, improving the effect of reinforcing the meltblown layer located in at least one intermediate layer. Controlling the "thickness ratio of the embossed fused portion," an index related to the thickness of the embossed fused portion, and the "effective embossed area ratio," an index related to the surface of the embossed fused portion, can contribute to applying a stronger emboss to the outermost layer of the spunbond nonwoven fabric layer in relatively low basis weight long-fiber nonwoven laminates, thereby increasing the rigidity of the outermost surface of the spunbond nonwoven fabric layer. As a result, it is presumed that a more balanced improvement was achieved in all aspects of water pressure resistance (absolute value), water pressure resistance per basis weight of the meltblown nonwoven fabric, and bending rigidity. In Figure 1, the fibers of the outermost layer (the surface layer corresponding to the upper part of the spunbond nonwoven fabric layer in Figure 1, the surface in contact with the embossing roll) are film-like, while the fibers remain in their original form in the surface layer (the surface layer corresponding to the lower part of the spunbond nonwoven fabric layer in Figure 1).

[0024] The basis weight (i.e., total basis weight) of the long-fiber nonwoven fabric laminate is 3.0 g / m². ２ ~10.0 g / m ２ The total weight is 5.0 g / m². ２ ~10.0 g / m ２ That's fine.

[0025] The long-fiber nonwoven laminate is a sheet-like material. The number of layers in the long-fiber nonwoven laminate is at least three, and is appropriately selected depending on the application of the long-fiber nonwoven laminate. The number of layers in the long-fiber nonwoven laminate may be three (i.e., SMS structure), four (e.g., SSMS structure, SMSS structure, or SMMS structure), or five or more. "SMS structure" refers to a structure in which a spunbond nonwoven layer, a meltblown nonwoven layer, and a spunbond nonwoven layer are laminated in this order. "SSMS structure" refers to a structure in which a spunbond nonwoven layer, a spunbond nonwoven layer, a meltblown nonwoven layer, and a spunbond nonwoven layer are laminated in this order. "SMSS structure" refers to a structure in which a spunbond nonwoven layer, a meltblown nonwoven layer, a spunbond nonwoven layer, and a spunbond nonwoven layer are laminated in this order. The term "SMMS structure" refers to a structure in which a spunbond nonwoven fabric layer, a meltblown nonwoven fabric layer, a meltblown nonwoven fabric layer, and a spunbond nonwoven fabric layer are laminated in this order. Whether the long-fiber nonwoven fabric laminate has an SMS structure or an SSMS structure, the effects of this disclosure can be achieved as long as the basis weight of the long-fiber nonwoven fabric laminate is within the numerical range specified above.

[0026] The thickness of the long-fiber nonwoven fabric laminate is adjusted as appropriate depending on the application of the long-fiber nonwoven fabric laminate, and may be between 0.05 mm and 10.0 mm, or between 0.1 mm and 1.0 mm.

[0027] (1.1) Physical properties The water pressure resistance per basis weight (hereinafter also referred to as "MB basis weight") of the meltblown nonwoven fabric layer of the long-fiber nonwoven fabric laminate is preferably 160 mmH ２ 0 / g / m ２ More specifically, 166 mmH ２ 0 / g / m ２ The above is true, and more preferably 170 mmH ２ 0 / g / m ２ That's all. The water pressure resistance per MB area is 250 mmH ２ 0 / g / m ２ The following is acceptable: Water pressure resistance per MB basis weight is 160 mmH ２ 0 / g / m ２ ~250mmH ２ 0 / g / m２ It may be 166 mmH ２ 0 / g / m ２ ~250mmH ２ 0 / g / m ２ This may be the case. The method for measuring water pressure resistance per MB basis weight is the same as the method described in the examples.

[0028] The rigidity of the long-fiber nonwoven fabric laminate is preferably less than 40 mm, more preferably 35 mm or less, and even more preferably less than 35 mm. The rigidity of the long-fiber nonwoven fabric laminate may be 25 mm or more, or 28 mm or more. The rigidity of the long-fiber nonwoven fabric laminate may be 25 mm or more and less than 40 mm, 25 mm or more and 35 mm or less, 25 mm or more and less than 35 mm, or 25 mm or more and less than 34 mm. The method for measuring rigidity is the same as in the example.

[0029] (1.2) Spunbond Nonwoven Layer The spunbond nonwoven layer functions as a protective layer for the meltblown nonwoven layer. The long-fiber nonwoven laminate has at least two spunbond nonwoven layers. The spunbond nonwoven layers are arranged on both surface layers of the long-fiber nonwoven laminate. The multiple spunbond nonwoven layers included in the long-fiber nonwoven laminate may be identical or different.

[0030] The basis weight of the spunbond nonwoven fabric layer is not particularly limited, but is 2.0 g / m². ２ ~9.5 g / m ２ It may be 5.0 g / m ２ ~9.0 g / m ２ This may be the case. The method for measuring the basis weight of the spunbond nonwoven fabric layer is the same as the method for measuring the MB basis weight in the example.

[0031] The average fiber diameter of the fibers contained in the spunbond nonwoven fabric layer (hereinafter also referred to as "SB fibers") is usually larger than the average fiber diameter of the fibers contained in the meltblown nonwoven fabric layer (hereinafter also referred to as "MB fibers"). The SB fiber diameter may be between 5.0 μm and 30.0 μm, or between 10.0 μm and 25.0 μm. The method for measuring the SB fiber diameter is the same as the method described in the examples.

[0032] The spunbond nonwoven fabric layer may contain multiple long fibers and may consist of multiple long fibers. The cross-sectional shape of the SB fibers is not particularly limited and examples include circular, elliptical, and irregularly shaped cross-sections. The SB fibers may be composite fibers or single-component fibers. It is preferable that the composite fibers consist of two or more thermoplastic resins. Examples of composite fiber configurations include core-sheath type, side-by-side type, sea-island type, and parallel type. Core-sheath type composite fibers may have a core and a sheath, and may be either concentric core-sheath type or eccentric core-sheath type. In eccentric core-sheath type composite fibers, the core may or may not be exposed on the surface. Sea-island type composite fibers have a sea phase and multiple island phases.

[0033] (1.2.1) The thermoplastic resin composition spunbond nonwoven fabric layer is composed of a thermoplastic resin composition (hereinafter also referred to as "resin composition (SB)"). The resin composition (SB) includes a thermoplastic resin.

[0034] (1.2.1.1) Thermoplastic resins Examples of thermoplastic resins include polyolefin resins, polyesters (e.g., polyethylene terephthalate and polybutylene terephthalate), polyamides (e.g., nylon-6 and nylon-66), polyvinyl chloride, polyimide, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl alcohol copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-acrylic acid ester-carbon monoxide copolymer, polyacrylonitrile, polycarbonate, polystyrene, and biodegradable resins (e.g., polylactic acid and polyhydroxyalkanoates). Thermoplastic resins may be used individually or in combination of at least two types.

[0035] The content of thermoplastic resin relative to the total amount of resin composition (SB) may be 70% to 100% by mass, 80% to 100% by mass, 90% to 100% by mass, or 98% to 100% by mass.

[0036] The resin composition (SB) may contain an olefin polymer, or may contain only an olefin polymer. The olefin polymer may be used alone, or in combination of two or more types.

[0037] Examples of olefin polymers include propylene polymers and polyolefins (excluding propylene polymers). Propylene polymers and polyolefins (excluding propylene polymers) may be used individually or in combination of at least two types. In particular, the thermoplastic resin preferably contains a propylene polymer as its main component, and more preferably contains a propylene homopolymer as its main component.

[0038] (1.2.1.1.1) Propylene Polymers Propylene polymers contain constituent units derived from propylene. Propylene polymers are propylene homopolymers or propylene copolymers. The propylene copolymer is preferably a copolymer of propylene and at least one α-olefin (e.g., ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, etc.). In particular, the propylene polymer preferably contains a propylene homopolymer, and more preferably is a propylene homopolymer.

[0039] The melting point of the propylene polymer is preferably 140°C or higher, more preferably 150°C or higher, even more preferably 155°C or higher, and particularly preferably 157°C to 165°C. When two or more propylene polymers are included, the "melting point of the propylene polymer" refers to the one with the higher temperature (the same applies to two or more components hereafter).

[0040] The melting point is defined as the peak top of the lowest temperature peak observed in the melting endothermic curve obtained by holding a sample at -100°C in a nitrogen atmosphere for 5 minutes and then increasing the temperature at 10°C / min using a differential scanning calorimeter (DSC). Specifically, it can be determined as the peak top of the lowest temperature peak observed in the melting endothermic curve obtained by using a differential scanning calorimeter (Perkin-Elmer, DSC-7), holding a 5 mg sample at -100°C in a nitrogen atmosphere for 5 minutes and then increasing the temperature at 10°C / min.

[0041] The melt flow rate (hereinafter also referred to as "MFR") of the propylene polymer is not particularly limited as long as the resin composition (SB) can be melt-spun, and is preferably 1 g / 10 min to 1000 g / 10 min, but may also be 5 g / 10 min to 500 g / 10 min, or 10 g / 10 min to 100 g / 10 min. The method for measuring the MFR of the propylene polymer is in accordance with ASTM D-1238, and the measurement conditions are 230°C and a load of 2160 g. When two or more propylene polymers are included, "MFR of propylene polymer" refers to the MFR of the resin composition containing two or more propylene polymers (the same applies hereinafter for two or more components).

[0042] The resin composition (SB) preferably contains a propylene polymer as its main component. Specifically, the content of the propylene polymer relative to the total amount of the resin composition (SB) is preferably 80% to 100% by mass, more preferably 90% to 100% by mass, and may be 98% to 100% by mass.

[0043] When the resin composition (SB) contains a propylene polymer as its main component, the melting point of the resin composition (SB) is preferably 140°C or higher, more preferably 150°C or higher, even more preferably 155°C or higher, and particularly preferably 157°C to 165°C.

[0044] (1.2.1.1.2) Polyolefins Polyolefins (excluding propylene-based polymers) are α-olefins alone or copolymers. α-olefins are α-olefins having 2 or more carbon atoms (excluding those with 3 carbon atoms). Polyolefins (excluding propylene-based polymers) preferably include homopolymers of α-olefins having 2 to 8 carbon atoms (excluding those with 3 carbon atoms), and more preferably are homopolymers of α-olefins having 2 to 8 carbon atoms (excluding those with 3 carbon atoms). Examples of α-olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene. Among these, ethylene is preferred as the α-olefin. Examples of polyolefins (excluding propylene-based polymers) include polyethylene (ethylene homopolymer), 1-butene polymers, and poly4-methyl-1-pentene.

[0045] (1.2.1.1.3) Biomass-derived thermoplastic resin The thermoplastic resin used in this disclosure (for example, a propylene polymer) may be derived from biomass raw materials. Since biomass-derived raw materials are carbon-neutral materials, the environmental burden in the manufacture of the spunbond nonwoven fabric layer can be reduced. Known monomers can be used as the monomers used as raw materials for the biomass-derived thermoplastic resin. A polymer of a thermoplastic resin synthesized using biomass-derived monomers as raw materials becomes a biomass-derived thermoplastic polymer. The content of the biomass-derived thermoplastic polymer in the raw material monomer is greater than 0% by mass, may be 100% by mass, or 100% by mass or less, relative to the total amount of raw material monomers. The thermoplastic polymer used as a raw material in this disclosure may include a thermoplastic polymer obtained by recycling, so-called recycled polymer. For example, the polymer described in DE102019127827 (A1) can be used.

[0046] (1.2.1.2) The additive resin composition (SB) may contain additives as long as it does not impair the purpose of this disclosure. Examples of additives include antioxidants, heat stabilizers, weather stabilizers, antistatic agents, slip agents, antifogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes, and hydrophilic agents.

[0047] (1.3) Meltblown nonwoven layer The meltblown nonwoven layer improves the water pressure resistance of the long fiber nonwoven laminate. The long fiber nonwoven laminate has at least one meltblown nonwoven layer. If the long fiber nonwoven laminate includes multiple meltblown nonwoven layers, the multiple meltblown nonwoven layers may be the same or different.

[0048] The basis weight (i.e., MB basis weight) of the meltblown nonwoven fabric layer is 0.5 g / m². ２ ~1.0 g / m ２ The MB basis weight is 0.5 g / m². ２ If the above conditions are met, the water pressure resistance and the water pressure resistance per basis weight of the meltblown nonwoven fabric layer can be set to the desired range. MB basis weight is 1.0 g / m ２ The following conditions allow the water pressure resistance and the water pressure resistance per basis weight of the meltblown nonwoven fabric layer to be within the desired range. From the viewpoint of the bending rigidity of the long-fiber nonwoven laminate, the MB basis weight is 0.6 g / m². ２ ~1.0 g / m ２ The following may be true: 0.7 g / m ２ Super 1.0g / m ２ It may also be less than 0.7 g / m ２ Super 1.0g / m ２ It may be less than [amount missing]. The method for measuring MB basis is the same as the measurement method described in the examples.

[0049] The ratio of the basis weight of the meltblown nonwoven fabric layer to the basis weight of the long-fiber nonwoven fabric laminate (hereinafter also referred to as the "MB basis weight ratio") is not particularly limited. From the viewpoint of improving bending rigidity, the MB basis weight ratio is preferably 6.0% or more and less than 20.0%, may be 6.5% to 18.0%, may be 7.5% to 18.0%, may be 8.0% to 18.0%, may be 6.5% to 14.0%, may be 7.5% to 14.0%, and may be 8.0% to 14.0%. From the viewpoint of achieving both water pressure resistance per unit weight of the meltblown nonwoven fabric layer and bending rigidity of the long-fiber nonwoven laminate, and also having good water pressure resistance (absolute value), the MB basis weight ratio is more preferably 7.5% to less than 20.0%, even more preferably 7.5% to 18.0%, and even more preferably 7.5% to 14.0%. In particular, a long-fiber nonwoven laminate having a thickness ratio of 19.0% to 35.0% of the embossed fused portion and an MB basis weight ratio of 6.0% to less than 20.0% is one preferred embodiment, and even with a relatively low basis weight ratio of the meltblown nonwoven fabric layer, the effects of this disclosure can be well-balanced.

[0050] The average fiber diameter of the MB fibers contained in the meltblown nonwoven fabric layer (i.e., MB fiber diameter) is not particularly limited and may be 0.5 μm to 5.0 μm, 1.0 μm to 2.0 μm, or 1.3 μm to 1.8 μm. Preferably, the average fiber diameter of the MB fibers contained in the meltblown nonwoven fabric layer (i.e., MB fiber diameter) is 0.5 μm to 5.0 μm. The effects of this disclosure can be achieved if the MB fiber diameter is 0.5 μm or larger. The method for measuring the MB fiber diameter is the same as the measurement method described in the examples.

[0051] The meltblown nonwoven fabric layer contains multiple long fibers and may consist of multiple long fibers. The cross-sectional shape of the MB fiber is not particularly limited and examples include circular, elliptical, and irregularly shaped cross-sections. The MB fiber may be a composite fiber or a single-component fiber. The composite fiber preferably has two or more thermoplastic resins as constituent components. Examples of composite fiber configurations include core-sheath type, side-by-side type, sea-island type, and parallel type. The core-sheath type composite fiber may have a core and a sheath, and may be either a concentric core-sheath type or an eccentric core-sheath type. In the eccentric core-sheath type composite fiber, the core may or may not be exposed on the surface. The sea-island type composite fiber has a sea phase and multiple island phases.

[0052] (1.3.1) The thermoplastic resin composition meltblown nonwoven fabric layer is composed of a thermoplastic resin composition (hereinafter also referred to as "resin composition (MB)"). The resin composition (MB) contains a thermoplastic resin.

[0053] Examples of thermoplastic resins for the resin composition (MB) include those similar to those exemplified as thermoplastic resins for the resin composition (SB).

[0054] The content of thermoplastic resin relative to the total amount of the resin composition (MB) may be 70% to 100% by mass, 80% to 100% by mass, 90% to 100% by mass, or 98% to 100% by mass.

[0055] The melt-spinning rate (MFR) of the propylene polymer is not particularly limited as long as the resin composition (MB) can be melt-spun. Preferably, it may be 1 g / 10 min to 3000 g / 10 min, 100 g / 10 min to 2000 g / 10 min, or 500 g / 10 min to 1500 g / 10 min. The method for measuring the MFR of the propylene polymer conforms to ASTM D-1238, and the measurement conditions are 230°C and a load of 2160 g. When two or more propylene polymers are included, "MFR of propylene polymer" refers to the MFR of the resin composition containing two or more propylene polymers (the same applies hereinafter for two or more components).

[0056] The resin composition (MB) preferably contains a propylene polymer as its main component. Specifically, the content of the propylene polymer relative to the total amount of the resin composition (MB) is preferably 80% to 100% by mass, more preferably 90% to 100% by mass, and may be 98% to 100% by mass.

[0057] When the resin composition (MB) contains a propylene polymer as its main component, the melting point of the resin composition (MB) is preferably 140°C or higher, more preferably 150°C or higher, even more preferably 155°C or higher, and particularly preferably 157°C to 165°C.

[0058] The resin composition (MB) may contain additives as long as they do not impair the purpose of this disclosure. Examples of additives include antioxidants, heat stabilizers, weather stabilizers, antistatic agents, slip agents, antifogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes, and hydrophilic agents.

[0059] (1.4) Preferred Embodiments The thermoplastic resin composition constituting the spunbond nonwoven fabric layer (i.e., resin composition (SB)) and the thermoplastic resin composition constituting the meltblown nonwoven fabric layer (i.e., resin composition (MB)) each preferably contain a propylene polymer as the main component. This makes it possible to increase the bonding strength of each layer constituting the long-fiber nonwoven fabric laminate after embossing.

[0060] (1.5) Applications The long-fiber nonwoven fabric laminates of this disclosure are used in textile products. Textile products are not particularly limited and include, for example, sanitary materials (e.g., diapers, sanitary products, first-aid supplies, hygiene products, masks, poultices, bandages, protective clothing, surgical gowns, and drapes), clothing materials (e.g., dustproof materials, supporters, interlinings, and adhesive interlinings), building materials (e.g., roofing materials and tufted carpet base materials), civil engineering articles (e.g., drain materials and filter materials), vehicle materials (e.g., automobile interiors and automobile parts), interiors (e.g., carpets, furniture components, fixtures, wall coverings, and decorative items), bedding (e.g., futon bags, pillowcases, and sheets), agricultural articles (e.g., greenhouse sheets and seedbed sheets), leather (e.g., base fabrics for artificial leather and synthetic leather), daily living materials (e.g., storage items, packaging materials, and bags), and industrial materials (e.g., industrial materials, electrical materials, and product base materials).

[0061] (2) Textile products The textile products of this disclosure include the filament nonwoven fabric laminates of this disclosure.

[0062] As for textile products, they are the same as those exemplified as textile products for which the long-fiber nonwoven fabric laminate of this disclosure is used. Because the long-fiber nonwoven fabric laminate of this disclosure is lightweight, the textile products of this disclosure are lighter than conventional products while possessing good water pressure resistance (water pressure resistance per MB basis weight) and rigidity.

[0063] (3) Diapers The diapers of the present disclosure include the long fiber nonwoven fabric laminate of the present disclosure.

[0064] The diaper of this disclosure may have a known configuration, except that it includes the long-fiber nonwoven fabric laminate of this disclosure. The long-fiber nonwoven fabric laminate of this disclosure is applicable to top sheets, second sheets, back sheets, and SAP (superabsorbent polymer) sheets, etc. In particular, the diaper of this disclosure is useful as a back sheet because it has good water pressure resistance.

[0065] (4) Method for manufacturing a long fiber nonwoven laminate The method for manufacturing a long fiber nonwoven laminate according to the present disclosure includes: preparing a web laminate having at least two spunbond webs and at least one meltblown web, with the spunbond webs arranged on both surface layers (hereinafter also referred to as the "preparation step"); and heat-sealing the spunbond webs and the meltblown webs containing the web laminate by embossing (hereinafter also referred to as the "heat-sealing step"). In the heat-sealing step (i.e., the heat-sealing step), the embossing speed is 530 m / min to 800 m / min, and the embossing temperature is 140°C to 150°C. The embossing linear pressure is 75 N / mm to 90 N / mm. The preparation step and the heat-sealing step are carried out in this order.

[0066] In this disclosure, "embossing" refers to a process in which a web laminate being transported at a constant speed is sandwiched between an embossing roll and a flat roll, and some of the multiple fibers contained in the web laminate are heat-pressed together. "Embossing speed" refers to the transport speed of the web laminate. The "embossing speed" of commercial lines is typically 900 m / min to 1500 m / min. "Embossing temperature" refers to the operating temperature of the embossing roll. "Embossing linear pressure" refers to the operating pressure of the embossing roll. It refers to the value obtained by dividing the load acting on the contact area between the outer surface and the outer surface of the flat roll by the axial length of the embossing roll at that contact area.

[0067] Because the method for manufacturing the long-fiber nonwoven fabric laminate of this disclosure has the above configuration, the long-fiber nonwoven fabric laminate of this disclosure has a low basis weight (for example, 10 g / m²). ２ The following conditions apply, and the basis weight of the meltblown nonwoven fabric layer is low (for example, 1.0 g / m²). ２ It is possible to manufacture a long-fiber nonwoven fabric laminate that has excellent water pressure resistance per basis weight of the meltblown nonwoven fabric layer and low bending rigidity, while having the following characteristics.

[0068] (4.1) Preparation process In the preparation process, the web laminate is prepared.

[0069] The web laminate is similar to the long-fiber nonwoven fabric laminate, except that the spunbond web and meltblown web contained within the web laminate are not heat-fused together.

[0070] The method for preparing the web laminate is not particularly limited and is appropriately selected depending on the layer configuration of the long-fiber nonwoven fabric laminate. The method for preparing the web laminate may be a known method. When the long-fiber nonwoven fabric laminate has an SMS structure, the web laminate can be obtained by performing spin-ray lamination, melt-blown lamination, and spin-ray lamination in that order using a known apparatus. When the long-fiber nonwoven fabric laminate has an SSMS structure, the web laminate can be obtained by performing spin-ray lamination, spin-ray lamination, melt-blown lamination, and spin-ray lamination in that order using a known apparatus.

[0071] (4.2) Heat fusion process In the heat fusion process, the spunbond web containing the web laminate and the meltblown web are heat-fused by embossing. This forms an embossed fused section. Specifically, the web laminate being conveyed at an embossing speed is sandwiched between an embossing roll and a flat roll, and some of the multiple fibers (i.e., SB fibers) contained in the web laminate are heat-compressed. At this time, the embossing speed is 530 m / min to 800 m / min, the embossing temperature is 140°C to 150°C, and the embossing linear pressure is 75 N / mm to 100 N / mm. This yields a long-fiber nonwoven fabric laminate.

[0072] The embossing roll has multiple embossed patterns (i.e., the top surfaces of the convex parts) on its surface. The embossing roll transfers the shapes of the multiple embossed patterns to a portion of the multiple SB fibers contained in the long-fiber nonwoven fabric laminate. The shapes of the multiple embossed patterns on the embossing roll are similar to the shapes exemplified as multiple embossed fusion parts. The area ratio of the multiple embossed patterns on the embossing roll (hereinafter also referred to as the "embossing ratio") is preferably 5% to 30%, more preferably 10% to 20%. The embossing ratio represents the ratio of the total area of ​​the multiple embossed patterns to the surface area of ​​the outer circumferential surface of the embossing roll.

[0073] The embossing speed is 530 m / min to 800 m / min. By slowing the embossing speed compared to normal and performing heat treatment over a relatively long period of time, the MB layer can be covered with a spunbond nonwoven fabric layer having appropriate rigidity, thereby reducing damage to the MB fibers due to embossing. From the viewpoint of imparting appropriate rigidity to the surface spunbond nonwoven fabric layer, the embossing speed is preferably 550 m / min or higher. From the viewpoint of improving the water pressure resistance (absolute value) of the long-fiber nonwoven laminate, the embossing speed is preferably 750 m / min or lower, more preferably 700 m / min or lower, even more preferably 690 m / min or lower, and even more preferably 680 m / min or lower. The embossing speed may be 530 m / min to 750 m / min, 530 m / min to 700 m / min, 530 m / min to 690 m / min, 530 m / min to 680 m / min, 550 m / min to 750 m / min, 550 m / min to 700 m / min, 550 m / min to 690 m / min, or 550 m / min to 680 m / min. In conventional technology, it was thought that slowing the embossing speed and performing heat treatment over a relatively long period of time would damage the MB fibers, but improvements in water resistance have been found within the above range of values.

[0074] The embossing temperature is 140°C to 150°C. In this disclosure, an embossing speed of 530 m / min to 800 m / min and an embossing temperature (roll operating temperature) of 140°C to 150°C are useful for achieving both water pressure resistance and bending rigidity per basis weight of the meltblown nonwoven fabric layer. It is preferable that the embossing temperature of both rolls is greater than 140°C and less than or equal to 150°C. In conventional light embossing, the embossing temperature of the embossing roll is sometimes set to 100°C or less to avoid damaging the fibers of the meltblown nonwoven fabric layer. In this disclosure, the embossing roll and the long-fiber nonwoven fabric laminate are brought into contact at a relatively high embossing temperature, with a low embossing linear pressure (embossing operating pressure), and over a period of time. This makes it possible to form an embossed fused portion on the surface layer of the long-fiber nonwoven fabric laminate (preferably the outermost layer of the spunbond nonwoven fabric layer) in which the fiber morphology of the SB fibers remains partially intact.

[0075] The embossing wire pressure is 75 N / mm to 100 N / mm, from the viewpoint of reducing damage to MB fibers. The embossing wire pressure may be 75 N / mm to 90 N / mm, or 78 N / mm to 88 N / mm. Embossing mark (mm ２ The embossing line pressure per inch is, from the same perspective, 206 N / mm². ３ ~275 N / mm ３ It may be 206 N / mm ３ ~247 N / mm ３ That's fine.

[0076] When the embossing speed is 530 m / min to 800 m / min and the embossing temperature is 140°C to 150°C, and both the resin composition (SB) and the resin composition (MB) contain a propylene polymer as a main component, the difference between the melting point of the resin composition (SB) and the melting point of the resin composition (MB) is preferably 0°C to 20°C, more preferably 0°C to 10°C, and even more preferably 0°C to 5°C. This ensures the bonding strength of each layer constituting the long-fiber nonwoven laminate during the heat-sealing process, while increasing the rigidity of the SB fibers and further reducing damage to the MB fibers in a low-basis-weight long-fiber nonwoven laminate containing a low-basis-weight meltblown nonwoven layer. Furthermore, due to the low-basis-weight meltblown nonwoven layer, the desired bending rigidity can be achieved in the low-basis-weight long-fiber nonwoven laminate.

[0077] The present disclosure is illustrated below with reference to examples and comparative examples. However, the present disclosure is not limited to the following examples.

[0078] [1] Measurement Method The MB fiber diameter, thickness ratio of the embossed fused portion, effective embossed area ratio, water pressure resistance, water pressure resistance per MB basis weight, and stiffness of the long-fiber nonwoven fabric laminates obtained in the examples and comparative examples were evaluated by the following method.

[0079] [1.1] Method of Measuring Basis Weight Ten test pieces of 300 mm (MD) and 250 mm (CD) were taken from the long-fiber nonwoven fabric laminate. The sampling locations were arbitrarily selected from 10 locations on the long-fiber nonwoven fabric laminate. Next, the mass (g) of each sampled test piece was measured using a top-loading electronic balance (manufacturer: A&D Manufacturing Co., Ltd.). The average value of the mass of each test piece was calculated. From the calculated average value, 1 m２ The value converted to mass per unit (g) was defined as the "basis weight of the long-fiber nonwoven fabric laminate" (i.e., the total basis weight).

[0080] Based on empirical rules, the resulting MB basis weight can be adjusted to the desired basis weight (i.e., the design value) by adjusting the operating conditions of the meltblown nonwoven fabric manufacturing equipment. The MB basis weight estimated from the operating conditions of the meltblown nonwoven fabric manufacturing equipment was defined as the "basis weight of the meltblown nonwoven fabric layer" (i.e., MB basis weight).

[0081] For example, by adjusting the resin discharge rate per hour [kg / h] and the screen speed (i.e., line speed [m / min]), a meltblown nonwoven fabric layer with a desired basis weight can be produced.

[0082] If the meltblown nonwoven fabric layer can be separated from the long-fiber nonwoven fabric laminate, the MB basis weight can be measured in the same manner as the basis weight measurement method for the long-fiber nonwoven fabric laminate.

[0083] If it is difficult to separate the meltblown nonwoven fabric layer from a long-fiber nonwoven fabric laminate, the MB basis weight can be measured using the following method. This allows for investigation of whether competitor products meet the numerical range for "meltblown nonwoven fabric layer basis weight." Specifically, a test piece is taken from the non-fused section, and the fibers with a diameter of 5 μm or more from the spunbond nonwoven fabric layer and the fibers with a diameter of less than 5 μm from the meltblown nonwoven fabric layer are separated from the test piece of the long-fiber nonwoven fabric laminate, and the mass (g) of each layer is determined. This allows for the determination of the mass ratio of each layer contained in the long-fiber nonwoven fabric laminate. 10m ２ Measure the mass of the test specimen. 10 m ２ The basis weight of each layer can be calculated using the measured mass of the test specimen and the measured mass ratio of each layer. The calculated MB basis weight and the MB basis weight estimated from the operating conditions of the meltblown nonwoven fabric manufacturing equipment can be considered to be approximately the same. Here, "10m ２ If a continuous test specimen cannot be obtained, multiple test specimens can be used. 10m ２ When using multiple test specimens as test specimens, the total area of ​​the multiple test specimens must be "10 m² ２Any test specimen will suffice. The embossed fused portion should be excluded from the test specimen.

[0084] [1.2] The MB fiber diameter long fiber nonwoven laminate was observed using a scanning electron microscope (manufacturer: Hitachi High-Tech Corporation, product name: scanning electron microscope "SU3500"), and images of the meltblown nonwoven layer were taken at a magnification of 3000x. Fibers formed by the fusion of MB fibers and resin lumps called shots were excluded from the measurement. The diameter of the measurable MB fibers was measured from the obtained images, and imaging and measurement were repeated until the total number of measured MB fibers exceeded 100. The arithmetic mean of the obtained MB fiber diameters was defined as the "average fiber diameter of the fibers contained in the meltblown nonwoven layer" (i.e., MB fiber diameter).

[0085] [1.3] The spunbond fiber nonwoven laminate was observed using an electron microscope (manufacturer: Hitachi High-Tech Corporation, product name: Scanning Electron Microscope "SU3500"), and an image of the spunbond nonwoven layer was taken at a magnification of 20x. The diameter of the measurable SB fibers was measured from the obtained image, and imaging and measurement were repeated until the total number of measured SB fibers exceeded 30. The arithmetic mean of the obtained SB fiber diameters was defined as the "average fiber diameter of the fibers contained in the spunbond nonwoven layer" (i.e., SB fiber diameter).

[0086] [1.4] Thickness ratio of the embossed fused portion [1.4.1] Observation of the cross-section of the embossed fused portion An arbitrary portion of the long-fiber nonwoven fabric laminate was selected and the long-fiber nonwoven fabric laminate was cut along the longest diagonal line passing through the center of the embossed fused portion. When cutting the long-fiber nonwoven fabric laminate, a cold spray was used to fix the long-fiber nonwoven fabric laminate in place. The cut long-fiber nonwoven fabric laminate was fixed to a jig with double-sided tape so that the cross-section of the embossed fused portion could be observed. The morphology of the cross-section of the embossed fused portion was observed at a magnification of 200x using a scanning electron microscope (SEM). Images of the area where the cross-section of the embossed fused portion exists were taken using the SEM. The above imaging operation was repeated while changing the position of the arbitrary part to be photographed until the total number of images taken was 20 or more.

[0087] [1.4.2] Measurement of the thickness of the embossed fused portion Using the images taken by the above method, the thickness of the embossed fused portion was calculated as follows using image processing software (ImageJ). Specifically, the portion other than the long-fiber nonwoven fabric laminate was cut out from the captured image, and the maximum thickness of the embossed fused portion was measured. The average of the thicknesses of the 20 measured points was defined as the "thickness of the embossed fused portion".

[0088] [1.4.3] A thickness measuring instrument with a presser plate of 9 mm or larger in diameter was prepared to measure the thickness of the long-fiber nonwoven laminate. Using the instrument, the thickness of the long-fiber nonwoven laminate was measured to 7 gf / cm². ２ A load was applied, and the laminated long-fiber nonwoven fabric was left for an appropriate time (for example, about 10 seconds) until the variation in thickness stabilized. Then, the thickness of 20 arbitrary locations on the laminated long-fiber nonwoven fabric was measured. The average value was defined as the "thickness of the laminated long-fiber nonwoven fabric."

[0089] [1.4.4] Calculation of Embossed Fuse Thickness Ratio Using the thickness of the embossed fuse obtained above and the thickness of the long-fiber nonwoven fabric laminate, the thickness ratio of the embossed fuse was calculated using the following formula (I). Formula (I): Thickness ratio of embossed fuse (%) = [Thickness of embossed fuse / Thickness of long-fiber nonwoven fabric laminate] × 100

[0090] [1.5] Effective Embossing Area Ratio [1.5.1] Measurement of Embossing Area An arbitrary portion of the long-fiber nonwoven fabric laminate was selected, and the morphology of the surface in contact with the embossing roll was observed using a scanning electron microscope (SEM) at a magnification of 50x. Images of the area where there are at least two embossing fusion parts with unbroken contours (hereinafter also referred to as "first specific images") were taken using the SEM. The above imaging operation was repeated while changing the position of the arbitrary portion to be photographed until the total number of first specific images taken reached 20 or more. Using the first specific images thus taken, the embossing area was calculated using image processing software (ImageJ) as follows. Specifically, planar figures that overlap the contours of each embossing fusion part were created using ImageJ, and the average value of the areas of the 20 planar figures (hereinafter also referred to as "average area") was calculated. This average area was defined as the "embossing area".

[0091] Embossed patterns are generally planar shapes (e.g., ellipses and rhombuses). The area of ​​the embossed pattern can also be calculated from the drawing of the embossed pattern on the embossing roll. If it is difficult to determine the outline of the embossed pattern from the long-fiber nonwoven fabric laminate, the area of ​​the embossed pattern obtained from the drawing of the embossing pattern on the embossing roll can be used.

[0092] [1.5.2] Measurement of the area of ​​the embossed fused portion An arbitrary portion of the long-fiber nonwoven fabric laminate was selected, and the morphology of the surface in contact with the embossing roll was observed using an SEM at a magnification of 50x. Images of the area where at least two embossed fused portions with unbroken contours existed (hereinafter also referred to as the "second specific image") were captured using an SEM at a magnification of 100x. The above capture operation was repeated while changing the position of the arbitrary portion to be captured until the total number of captured second specific images reached 20 or more. Using the second specific images thus captured, the area of ​​the embossed fused portion was measured using image processing software (ImageJ) as follows. Specifically, the portion other than the embossed fused portion was cut out from the captured second specific image to create a grayscale image (8-bit image), and the grayscale image was binarized. This resulted in a binarized image. During binarization, the binarization threshold was set so that pixel values ​​from 0 to 127 in the grayscale image were black, and pixel values ​​from 128 to 255 were white. The area of ​​the black region in the binarized image was calculated as the area of ​​the embossed fusion. The average of the areas measured at 20 points was used as the "area of ​​the embossed fusion."

[0093] [1.5.3] Calculation of Effective Embossed Area Ratio Using the area of ​​the embossed mark and the area of ​​the embossed fusion portion obtained above, the effective embossed area ratio was calculated using the following formula (II). Formula (II): Effective embossed area ratio (%) = [Area of ​​embossed fusion portion / Area of ​​embossed mark] × 100

[0094] [1.6] Water pressure resistance and water pressure resistance per MB basis weight [1.6.1] Water pressure resistance Five 150 mm square test pieces were taken from the long fiber nonwoven fabric laminate. In accordance with Method A (low water pressure method) specified in JIS L 1092 (2009), water pressure was applied to the test piece at a pressure increase rate of 100 mm / min, and the water pressure was measured when three drops of water came out of the test piece. The measurement was repeated 10 times, and the average value was calculated. The average value was defined as the "water pressure resistance of the long fiber nonwoven fabric laminate".

[0095] [1.6.2] Water pressure resistance per MB basis weight Using the water pressure resistance and the basis weight of the meltblown nonwoven fabric layer obtained by the above method, the "water pressure resistance per MB basis weight" was calculated using the following formula (III). Using the water pressure resistance per MB basis weight, the water pressure resistance per MB basis weight was evaluated according to the following evaluation criteria. The acceptable evaluation of water pressure resistance per MB basis weight is "A1". Formula (III): Water pressure resistance per MB basis weight = Water pressure resistance / Basis weight of the meltblown nonwoven fabric layer

[0096] [1.6.2.1] Evaluation Criteria Evaluation A1: 160mmH ２ 0 / g / m ２ ≤MB basis weight water pressure resistance evaluation B1: 130 mmH ２ 0 / g / m ２ ≤ MB basis weight water pressure resistance < 160 mmH ２ 0 / g / m ２ Rating C1: Water pressure resistance per MB base weight < 130 mmH ２ 0 / g / m ２

[0097] [1.7] Ten 200 mm x 150 mm test specimens were taken from the rigid-flexible long-fiber nonwoven fabric laminate. Five of the test specimens (hereinafter also referred to as "test specimen (MD)") were taken so that the MD of the spunbond nonwoven fabric layer on the side in contact with the embossing roll was in the longitudinal direction of the test specimen. Five of the test specimens (hereinafter also referred to as "test specimen (CD)") were taken so that the CD of the spunbond nonwoven fabric layer on the side in contact with the embossing roll was in the short direction of the test specimen. The measurements were taken in accordance with Method A (45° cantilever method) specified in JIS L 1096 (2010) as follows. Specifically, the test specimen (MD) was placed on a horizontal table with a 45° inclination at one end, with the side in contact with the embossing roll facing upwards. Next, the test specimen was slid and moved in the direction of the inclination. The direction of movement of the test specimen (MD) was in the longitudinal direction of the test specimen (MD). The position of the midpoint of one end of the test specimen (MD) when it touched the inclined plane was read from the scale of the horizontal table. The length the test specimen (MD) moved was defined as the stiffness of the MD. The stiffness of the CD was measured in the same manner as the measurement of the stiffness of the MD, except that the direction of movement of the test specimen (MD) was changed to the direction of the shorter side of the test specimen (MD). For each test specimen, the stiffness of the MD and the stiffness of the CD were measured five times each, and the average values ​​of the stiffness of the MD and the CD were calculated. For 10 test specimens, the average values ​​of the stiffness of the MD and the CD were calculated. The "stiffness of the long-fiber nonwoven laminate" was calculated using the following formula (IV). The stiffness of the long-fiber nonwoven laminate was evaluated using the following evaluation criteria. An acceptable stiffness rating is "A2" or "B2". Equation (IV) = Stiffness of the long-fiber nonwoven laminate = (Average stiffness of MD from 10 test specimens + Average stiffness of CD from 10 test specimens) / 2

[0098] [1.7.1] Evaluation Criteria Evaluation A2: Rigidity of long-fiber nonwoven laminate < 35 mm Evaluation B2: 35 mm ≤ Rigidity of long-fiber nonwoven laminate < 40 mm Evaluation C2: 40 mm ≤ Rigidity of long-fiber nonwoven laminate

[0099] [2] Examples and Comparative Examples [2.1] Example 1 A nonwoven laminate (layer structure: SSMS structure) was prepared as follows. The nonwoven laminate (layer structure: SSMS structure) is made up of a spunbond nonwoven layer, a meltblown nonwoven layer, a spunbond nonwoven layer, and a spunbond nonwoven layer laminated in this order. The physical properties of each layer and the physical properties of the long-fiber nonwoven laminate are shown in Table 1.

[0100] [2.1.1] Preparation Process [2.1.1.1] Spin-Laminated The following component 1 was supplied to a spunbond nonwoven fabric manufacturing apparatus, melt spinning was performed, and a spunbond web (i.e., the first layer) was deposited on a screen.

[0101] Component 1: Propylene homopolymer with a melting point of 162°C and MFR of 60 g / 10 min (measured at a temperature of 230°C and a load of 2160 g according to ASTM D1238; the same applies hereafter unless otherwise specified).

[0102] [2.1.1.2] Meltblown Lamination The following component 2 was supplied to the die of the meltblown nonwoven fabric manufacturing apparatus, and from the heated die, it was discharged together with cooling high-speed air blown from both sides of the nozzle using a meltblown nozzle, thereby depositing a meltblown web (i.e., the second layer) on the first layer. This obtained a two-layer web.

[0103] Component 2: Propylene homopolymer with a melting point of 159°C and an MFR of 850 g / 10 min.

[0104] [2.1.1.3] Spin-lay lamination The above component 1 was supplied to a spunbond nonwoven fabric manufacturing apparatus, melt spinning was performed, and a spunbond web (i.e., the third layer) was deposited on the second layer of the two-layer web. A three-layer web was obtained.

[0105] [2.1.1.4] Spin-lay lamination The above component 1 was supplied to a spunbond nonwoven fabric manufacturing apparatus, melt spinning was performed, and a spunbond web (i.e., the fourth layer) was deposited on the third layer of the three-layer web. A web laminate was obtained. The web laminate is made up of spunbond web, melt-blown web, spunbond web and spunbond web laminated in this order.

[0106] [2.1.2] Heat fusion process Next, the web laminate was heat-fused using the following embossing roll under the following embossing conditions. This yielded a long-fiber nonwoven fabric laminate (layer structure: SSMS).

[0107] [2.1.2.1] Embossing Roll Embossing Engraving Rate: 18%

[0108] [2.1.2.2] Embossing conditions Embossing temperature: 144°C Embossing linear pressure: 80 N / mm Embossing speed: 613 m / min

[0109] [2.2] Examples 2-6 and Comparative Examples 1-10 Nonwoven laminates were prepared in the same manner as in Example 1, except that the total basis weight and other parameters were changed as shown in Tables 1-3.

[0110] Figure 1 shows an SEM image of a cross-section of the embossed fused portion of the long-fiber nonwoven fabric laminate of Example 3. Figure 1 shows the long-fiber nonwoven fabric laminate placed on a base. The large perforated layer occupying the lower half of the embossed fused portion in Figure 1 is the base. As shown in Figure 1, it was confirmed that in the embossed fused portion, there are multiple fibers that have not been completely formed into a film in the thickness direction of the long-fiber nonwoven fabric laminate (in other words, multiple fibers that are partially melted but maintain their fiber shape, located below the upper part of the cross-section of the nonwoven fabric).

[0111] Figure 2 shows an SEM image of the embossed fused portion on the surface of the long-fiber nonwoven fabric laminate of Example 3. As shown in Figure 2, multiple fibers maintaining the shape of non-film-formed fibers can be seen within and near the periphery of the embossed fused portion, and it was confirmed that there are also areas in the embossed fused portion where the fibers are not fused to each other.

[0112] Figure 3 shows an SEM image of an example of an embossed fusion portion on the surface of a long-fiber nonwoven fabric laminate of a comparative example. It was confirmed that the area where the SB fibers in the embossed fusion portion shown in Figure 3 are film-formed is larger than the area where the SB fibers in the embossed fusion portion shown in Figure 2 are film-formed.

[0113] [3] Results

[0114]

[0115]

[0116] In Tables 1 to 3, "laminated material" refers to a long-fiber nonwoven fabric laminate.

[0117] [3.1] In Comparative Examples 1 to 10 of the long-fiber nonwoven fabric laminates, the thickness ratio of the embossed fused portion was not within the range of 19.0% to 35.0%. In Comparative Examples 1, 5, 8, and 9, the MB basis weight was 0.5 g / m². ２ ~1.0 g / m ２ It was not within the range. In Comparative Example 3, the total basis weight of the long-fiber nonwoven fabric laminate was 3.0 g / m². ２ ~10.0 g / m ２ It was not within the specified range. Therefore, the evaluation of "water pressure resistance per MB basis weight" for Comparative Examples 1, 2, 4-10 was not "A1". The evaluation of "rigidity / flexibility" for Comparative Examples 1-3, 6 was not "A2" or "B2". As a result of these findings, it was found that the long-fiber nonwoven fabric laminates of Comparative Examples 1-10 were not "long-fiber nonwoven fabric laminates that have low basis weight for both the long-fiber nonwoven fabric laminate and the meltblown nonwoven fabric layer, yet exhibit excellent water pressure resistance per basis weight of the meltblown nonwoven fabric layer and low bending rigidity".

[0118] In Examples 1 to 6, the long-fiber nonwoven laminate contained at least two spunbond nonwoven layers and at least one meltblown nonwoven layer. The spunbond nonwoven layers were arranged on both surface layers of the long-fiber nonwoven laminate. The basis weight of the meltblown nonwoven layer was 0.5 g / m². ２ ~1.0 g / m ２ The total basis weight of the long-fiber nonwoven laminate was 3.0 g / m². ２ ~10.0 g / m ２ The thickness ratio of the embossed fused portion was 19.0% to 35.0%. Therefore, the water pressure resistance evaluation per MB basis weight was "A1". The rigidity evaluation was "A2" or "B2". As a result of these findings, it was found that the long-fiber nonwoven fabric laminates of Examples 1 to 6 are "long-fiber nonwoven fabric laminates that have a low basis weight, yet exhibit excellent water pressure resistance per basis weight of the meltblown nonwoven fabric layer, and have low bending rigidity".

[0119] [3.2] Methods for Manufacturing Long Fiber Nonwoven Laminates In Comparative Examples 1 to 7, the embossing temperature in the heat-sealing process was not within the range of 140°C to 150°C. In Comparative Examples 8 to 9, the embossing speed in the heat-sealing process was not within the range of 530 m / min to 800 m / min. In Comparative Example 10, the embossing linear pressure in the heat-sealing process was not within the range of 75 N / mm to 100 N / mm. Therefore, the evaluation results for Comparative Examples 1 to 10 were as described above. As a result of these findings, it was found that the methods for manufacturing long fiber nonwoven laminates in Comparative Examples 1 to 10 are not "methods for manufacturing long fiber nonwoven laminates that have a low basis weight, excellent water pressure resistance per basis weight of the meltblown nonwoven layer, and low bending rigidity."

[0120] In Examples 1 to 6, the embossing temperature in the heat-sealing process was in the range of 140°C to 150°C. The embossing speed in the heat-sealing process was in the range of 530 m / min to 800 m / min. The embossing linear pressure in the heat-sealing process was in the range of 75 N / mm to 100 N / mm. Therefore, the evaluation results for Examples 1 to 6 were as described above. As a result, it was found that the manufacturing method for the long-fiber nonwoven fabric laminate in Examples 1 to 6 is "a method for manufacturing a long-fiber nonwoven fabric laminate that can produce a long-fiber nonwoven fabric laminate in which the long-fiber nonwoven fabric laminate and the meltblown nonwoven fabric layer have low basis weight, yet have excellent water pressure resistance per basis weight of the meltblown nonwoven fabric layer and low bending rigidity."

[0121] The disclosure of Japanese Patent Application No. 2025-057235, filed on 28 March 2025, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A long-fiber nonwoven laminate comprising at least two spunbond nonwoven layers and at least one meltblown nonwoven layer, wherein the spunbond nonwoven layers are arranged on both surface layers of the long-fiber nonwoven laminate, and the basis weight of the meltblown nonwoven layer is 0.5 g / m². ２ ~1.0 g / m ２ The basis weight of the aforementioned long-fiber nonwoven fabric laminate is 3.0 g / m². ２ ~10.0 g / m ２ The long-fiber nonwoven fabric laminate wherein the thickness ratio of the embossed fused portion of the long-fiber nonwoven fabric laminate is 19.0% to 35.0%.

2. The long-fiber nonwoven fabric laminate according to claim 1, wherein the ratio of the basis weight of the meltblown nonwoven fabric layer to the basis weight of the long-fiber nonwoven fabric laminate is 6.0% or more and less than 20.0%.

3. The long-fiber nonwoven fabric laminate according to claim 1, wherein the effective embossed area ratio of the long-fiber nonwoven fabric laminate is 40.0% or more and 85.0% or less.

4. The long-fiber nonwoven laminate according to claim 1, wherein the average fiber diameter of the fibers contained in the meltblown nonwoven layer is 0.5 μm to 5.0 μm.

5. The long-fiber nonwoven laminate according to claim 1, wherein the thermoplastic resin composition constituting the spunbond nonwoven layer and the thermoplastic resin composition constituting the meltblown nonwoven layer each contain a propylene polymer as a main component.

6. A textile product comprising a long-fiber nonwoven fabric laminate according to any one of claims 1 to 5.

7. A diaper comprising a long-fiber nonwoven fabric laminate according to any one of claims 1 to 5.

8. A method for manufacturing a long-fiber nonwoven fabric laminate, comprising: preparing a web laminate having at least two spunbond webs and at least one meltblown web, with the spunbond webs arranged on both surface layers; and heat-sealing the spunbond webs and meltblown webs containing the web laminate by embossing, wherein the heat-sealing is performed at an embossing speed of 530 m / min to 800 m / min, an embossing temperature of 140°C to 150°C, and an embossing linear pressure of 75 N / mm to 100 N / mm.

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