Nonwoven fabric and use thereof

Abstract

The problem to be solved by the present invention is to provide a nonwoven fabric having excellent adhesion to the skin and excellent water resistance.　This nonwoven fabric contains an elastomer fiber, has a thickness of 200 μm or less, a ratio ((air permeability) / (basis weight)) of an air permeability (cm3 / cm2•s) to a basis weight (g / m2) of 1.0 or less, and a bulk density of 0.47 g / cm3 or more. For example, the nonwoven fabric may have a basis weight of 10-100 g / m2. In the nonwoven fabric, the elastomer fiber may be a urethane-based elastomer fiber.

Description

Nonwoven fabrics and their uses Related Applications

[0001] This application claims priority from Japanese Patent Application No. 2024-014758, filed February 2, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a nonwoven fabric containing elastomeric fibers, and to a medical patch and a wearable device each containing the nonwoven fabric.

[0003] Films have traditionally been used as the substrate for medical patches that are applied to the skin, such as wound dressings and adhesive bandages. However, films have poor self-supporting properties and are prone to wrinkling, making them difficult to handle.

[0004] Therefore, nonwoven fabrics have been proposed as the substrate of medical patches, and nonwoven fabrics containing elastomer fibers have been proposed in consideration of the conformability when applied to the skin. For example, Patent Document 1 (JP-A-11-12910) describes a nonwoven fabric that (i) comprises an elastic nonwoven fabric in which elastic short fibers made of an elastomer and having an average diameter of 0.1 to 20 μm are randomly arranged, (ii) the elastic short fibers are fused to each other at at least one point, and (iii) the elastic nonwoven fabric has a thickness of 0.02 to 1 mm and a density of 500 g / m ２ - Moisture permeability of 24 hours or more and 90 cc / cm ２ A medical patch base fabric characterized by having an air permeability of 1000 psi / sec or less is disclosed.

[0005] Furthermore, Patent Document 2 (JP 2023-147247 A) discloses a meltblown nonwoven fabric having an average fiber diameter of less than 6.5 μm, which contains a thermoplastic polyurethane elastomer having a number average molecular weight (Mn) of 100,000 or more and a molecular weight distribution (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 2.4 or less, and describes its use as a medical material.

[0006] JP 11-12910 A JP 2023-147247 A

[0007] Medical patches must be able to prevent the penetration of moisture and bacteria from the outside, and so their base materials must be water-resistant. However, while films have excellent water resistance, nonwoven fabrics have voids, making water resistance problematic. In fact, the elastic nonwoven fabric actually obtained in Patent Document 1 has poor water resistance.

[0008] Although Patent Document 2 evaluates the water pressure resistance relative to the basis weight, the water pressure resistance of the meltblown nonwoven fabric actually obtained was still insufficient, leaving room for improvement. Furthermore, medical patches must be resistant to peeling so that they can be fixed to the skin for a long period of time, and therefore must adhere well to the skin. Therefore, a thin nonwoven fabric must be used as the substrate to minimize unevenness when applied to the skin. However, the thickness of the meltblown nonwoven fabric actually obtained in Patent Document 2 was not measured, and its adhesion to the skin is unknown.

[0009] Therefore, an object of the present invention is to provide a nonwoven fabric that has excellent adhesion to the skin and excellent water resistance.

[0010] As a result of intensive research to solve the above problems, the present inventors have found that, while reducing the thickness of a nonwoven fabric containing elastomeric fibers improves adhesion to the skin, reducing the thickness also tends to reduce water resistance. After further research, they have found that water resistance can be improved by reducing the ratio of breathability to basis weight within a specific range and increasing the bulk density within a specific range, thereby completing the present invention.

[0011] That is, the present invention can be configured in the following aspects: [Aspect 1] A nonwoven fabric containing elastomeric fibers, having a thickness of 200 μm or less (preferably 10 to 200 μm, more preferably 13 to 150 μm, even more preferably 15 to 100 μm, and even more preferably 20 to 70 μm), and an air permeability (cm ３ / cm ２ s) and basis weight (g / m ２) (air permeability / basis weight) is 1.0 or less (preferably 0.0005 to 1.0, more preferably 0.0005 to 0.1, even more preferably 0.001 to 0.05, and still more preferably 0.003 to 0.01), and the bulk density is 0.47 g / cm ３ or more (preferably 0.47 to 1.00 g / cm ３ , more preferably 0.50 to 0.90 g / cm ３ , more preferably 0.53 to 0.80 g / cm ３ Aspect 2: The nonwoven fabric according to aspect 1, having a basis weight of 10 to 100 g / m ２ (preferably 15 to 80 g / m ２ , more preferably 20 to 60 g / m ２ , more preferably 21 to 45 g / m ２ ). [Aspect 3] The nonwoven fabric according to aspect 1 or 2, wherein the elastomeric fibers are urethane-based elastomer fibers. [Aspect 4] The nonwoven fabric according to any one of aspects 1 to 3, wherein the stress at 25% elongation in at least one of the plane directions is 10 N / 5 cm or less (preferably 8 N / 5 cm or less, more preferably 7 N / cm or less). [Aspect 5] The nonwoven fabric according to any one of aspects 1 to 4, wherein the elongation in at least one of the plane directions is 200% or more (preferably 250% or more, more preferably 280% or more). [Aspect 6] The nonwoven fabric according to any one of aspects 1 to 5, wherein the water pressure resistance measured by the low water pressure method of JIS L 1092:2009 is 170 mmH ２ O or higher (preferably 200 mmH ２ 0 or more, more preferably 230 mmH ２ A nonwoven fabric having an average fiber diameter of 0 or more. [Aspect 7] The nonwoven fabric according to any one of Aspects 1 to 6, wherein nonwoven fabrics having different average fiber diameters are laminated together. [Aspect 8] A medical adhesive patch comprising the nonwoven fabric according to any one of Aspects 1 to 7. [Aspect 9] The medical adhesive patch according to Aspect 8, which comprises an adhesive layer. [Aspect 10] A wearable device comprising the nonwoven fabric according to any one of Aspects 1 to 7. [Aspect 11] The wearable device according to Aspect 10, which comprises an adhesive layer.

[0012] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms, including "at least one," unless the content clearly dictates otherwise. As used herein, the terms "and / or," "at least one," and "one or more" include any and all combinations of the associated listed items.

[0013] It should be noted that any combination of at least two elements disclosed in the claims and / or the specification and / or the drawings is included in the present invention, and in particular any combination of two or more of the claims set forth in the claims is included in the present invention.

[0014] The nonwoven fabric of the present invention has excellent adhesion to the skin and excellent water resistance, and can be used for medical patches and wearable devices.

[0015] The present invention will be more clearly understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings. The drawings are not necessarily drawn to scale and are exaggerated to illustrate the principles of the present invention. However, the embodiments and drawings are merely for illustration and explanation and should not be used to define the scope of the present invention, which is defined by the appended claims.

[0023] Figure 1 is a schematic perspective view of a nonwoven fabric of one embodiment for illustrating a method for measuring bending resistance. Figure 2 is a schematic perspective view of a nonwoven fabric of one embodiment for illustrating a method for measuring bending resistance. Figure 3 is a schematic cross-sectional view showing one embodiment of a collection method using a melt-blowing method. Figure 4 is a schematic cross-sectional view showing one embodiment of a collection method using a melt-blowing method. Figure 5 is a schematic cross-sectional view showing one embodiment of a collection method using a melt-blowing method.

[0016] The nonwoven fabric contains elastomeric fibers, which have excellent elasticity and low tensile stress, and thus the inclusion of the elastomeric fibers can increase the elasticity and flexibility of the nonwoven fabric, thereby improving its conformability when applied to the skin.

[0017] The elastomer fiber is a fiber containing an elastomer, and the elastomer is preferably a thermoplastic elastomer. The thermoplastic elastomer is a copolymer composed of hard segments and soft segments. Specific examples of the thermoplastic elastomer include urethane-based elastomers, styrene-based elastomers, olefin-based elastomers, ester-based elastomers, amide-based elastomers, and vinyl chloride-based elastomers, depending on the type of hard segment. From the viewpoint of thermal stability during nonwoven fabric production, preferred elastomer fibers are urethane-based elastomer fibers containing urethane-based elastomers, styrene-based elastomer fibers containing styrene-based elastomers, and ester-based elastomer fibers containing ester-based elastomers. Furthermore, from the viewpoint of excellent stretchability, urethane-based elastomer fibers are more preferred. The nonwoven fabric may contain these elastomer fibers alone or in combination.

[0018] The elastomer fiber may contain components other than the elastomer, provided that the effects of the present invention are not impaired. Examples of such components include thermoplastic resins and various additives. Examples of thermoplastic resins include polyolefin resins such as polyethylene, polypropylene, polybutene, polymethylpentene, and ethylene-propylene copolymers; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamide resins such as polyamide 6 and polyamide 66; and acrylic polymers such as polyacrylic acid, polymethacrylic acid, polyacrylic acid esters, and polymethacrylic acid esters. The elastomer fiber may contain 50% by weight or more of the elastomer, preferably 60% by weight or more, more preferably 80% by weight or more, even more preferably 90% by weight or more, and even more preferably 95% by weight or more.

[0019] To improve the water resistance of nonwoven fabrics, it is preferable to improve the hydrophobicity of the nonwoven fabric. For example, a hydrophobic group may be introduced into the molecule of the elastomer contained in the elastomeric fiber. For example, a hydrophobic group such as a hydrocarbon group or a fluorine-containing group may be introduced into the molecular end of the elastomer. In the case of a hydrocarbon group, the hydrophobicity can be adjusted by adjusting the number of carbon chains. Alternatively, a hydrophobic group may be introduced into the molecular chain of the elastomer. For example, a urethane-based elastomer is composed of a soft segment formed from a long-chain polyol and a diisocyanate and a hard segment formed from a short-chain glycol and a diisocyanate. The polyol for the soft segment may be a hydrophobic polyol such as polybutadiene polyol or acrylic polyol.

[0020] The elastomeric fibers constituting the nonwoven fabric may have an average fiber diameter of 20 μm or less, from the viewpoint of increasing the density of the nonwoven fabric. Furthermore, from the viewpoint of increasing the density of the nonwoven fabric and improving the self-supporting property, the average fiber diameter of the elastomeric fibers may be preferably 0.1 to 18 μm, and more preferably 1 to 15 μm. In this specification, when the cross section of the elastomeric fiber perpendicular to the fiber axis direction (fiber cross section) is not a perfect circle (for example, an irregular cross section such as an ellipse or polygon), the cross-sectional area is measured, and the diameter of the perfect circle is converted into the fiber diameter assuming that the fiber cross section is a perfect circle.

[0021] The elastomeric fibers constituting the nonwoven fabric may be either long or short fibers, but are preferably long fibers from the viewpoint of stretchability. In this specification, long fibers are fibers that are continuous to a certain length and can be distinguished from short fibers that are intentionally cut to a predetermined fiber length. For example, fibers that constitute long-fiber nonwoven fabrics obtained by the melt-blowing method or the spunbonding method are considered to be long fibers.

[0022] The nonwoven fabric may contain elastomer fibers having a modified cross section. In this specification, a modified cross section means a fiber cross section that is not a perfect circle. When a precursor nonwoven fabric is obtained by pressing a precursor nonwoven fabric, as in the nonwoven fabric manufacturing method described below, even if the cross section of the elastomer fibers constituting the precursor nonwoven fabric is a perfect circle, the elastomer fibers are compressed by the pressing, and the fiber cross section is deformed from a perfect circle to a modified cross section.

[0023] The nonwoven fabric may contain 50% by weight or more of elastomeric fibers, preferably 80% by weight or more, more preferably 90% by weight or more, even more preferably 95% by weight or more, and even more preferably 98% by weight or more.

[0024] In order to improve the water resistance of the nonwoven fabric, the nonwoven fabric may further contain hydrophobic fibers in addition to the elastomeric fibers. Examples of hydrophobic fibers include polyolefin fibers such as polyethylene fibers and polypropylene fibers, and polyester fibers.

[0025] To improve the water resistance of the nonwoven fabric, a water repellent may be applied to the surface of the fibers constituting the nonwoven fabric, or may be mixed into the fibers as an additive. Examples of water repellents include fluorine-based water repellents, polysiloxane-based water repellents, and paraffin-based water repellents.

[0026] The nonwoven fabric has a thickness of 200 μm or less. When the nonwoven fabric is used as a substrate for a medical patch or the like that is applied to the skin, reducing the thickness of the nonwoven fabric can improve adhesion to the skin. Specifically, when applied to the skin, the difference in level between the skin and the patch can be reduced, thereby reducing external snagging and preventing the edges from curling, resulting in less peeling. Furthermore, the nonwoven fabric has good compatibility with the skin, reducing the discomfort felt when applied to the skin. The thickness of the nonwoven fabric may preferably be 150 μm or less, more preferably 100 μm or less, and even more preferably 70 μm or less. Furthermore, the lower limit of the thickness of the nonwoven fabric is not particularly limited, but may be, for example, 10 μm or more, preferably 13 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more, from the viewpoint of self-supporting properties. In this specification, the thickness is a value measured by the method described in the Examples below.

[0027] The nonwoven fabric has a breathability (cm ３ / cm ２ s) and basis weight (g / m ２ ) (air permeability / basis weight) is 1.0 or less, and the bulk density is 0.47 g / cm ３That's all. Even when the thickness of a nonwoven fabric is thin as described above, water resistance can be improved by reducing the ratio of air permeability to basis weight within a specific range and increasing the bulk density within a specific range. Bulk density is an index that indicates how tightly packed the fibers are in three dimensions; the higher the bulk density, the fewer voids there are and the more densely packed the fibers are. Furthermore, air permeability is an index that indicates the degree of unevenness in fiber density. That is, air permeability is obtained by measuring the amount of air passing through the gaps between the fibers of a nonwoven fabric. When the fiber density unevenness is large, the amount of air passing through areas with fewer fibers increases, and therefore the air permeability tends to be higher than when the fiber density unevenness is small. Air permeability is expressed as a ratio to the basis weight (air permeability / basis weight), an index that takes the amount of fiber into account, and a smaller ratio of air permeability to basis weight indicates smaller unevenness in fiber density. Generally, nonwoven fabrics are made up of fibers, and therefore voids exist between the fibers, allowing water to seep in through these voids, making it difficult to improve water resistance. However, by ensuring that both the ratio of air permeability to basis weight and the bulk density are within specific ranges, the fabric has a structure in which the fibers are densely packed evenly, which reduces the water pressure that tries to seep into the nonwoven fabric, resulting in excellent water resistance.

[0028] The ratio of the air permeability to the basis weight of the nonwoven fabric (air permeability / basis weight) may be preferably 0.1 or less, more preferably 0.05 or less, and even more preferably 0.01 or less. The lower limit of the ratio of the air permeability to the basis weight of the nonwoven fabric (air permeability / basis weight) is not particularly limited, but may be, for example, 0.0005 or more, preferably 0.001 or more, and more preferably 0.003 or more, from the viewpoint of ensuring moisture permeability.

[0029] The breathability of the nonwoven fabric is set to 10 cm from the viewpoint of reducing unevenness in fiber density. ３ / cm ２ ・s or less, preferably 3.0 cm ３ / cm ２ s or less, more preferably 1.0 cm ３ / cm ２ s or less, more preferably 0.8 cm ３ / cm ２The lower limit of the air permeability of the nonwoven fabric is not particularly limited, but from the viewpoint of ensuring moisture permeability, for example, it may be 0.1 cm ３ / cm ２ In this specification, the air permeability is a value measured by the method described in the examples below.

[0030] The basis weight of the nonwoven fabric is 10 to 100 g / m from the viewpoint of self-supporting property and flexibility. ２ and preferably 15 to 80 g / m ２ , more preferably 20 to 60 g / m ２ , more preferably 21 to 45 g / m ２ In this specification, the basis weight is a value measured by the method described in the examples below.

[0031] The bulk density of the nonwoven fabric is preferably 0.50 g / cm ３ More preferably, 0.53 g / cm ３ The upper limit of the bulk density of the nonwoven fabric is not particularly limited, but from the viewpoint of moisture permeability and flexibility, it may be, for example, 1.00 g / cm ３ or less, preferably 0.90 g / cm ３ or less, more preferably 0.80 g / cm ３ In this specification, the bulk density is a value measured by the method described in the Examples below.

[0032] The nonwoven fabric may be a laminate comprising multiple nonwoven fabric layers, as long as its thickness, ratio of air permeability to basis weight, and bulk density are within the above-mentioned specific ranges. In this specification, even when the nonwoven fabric is a laminate, the thickness, ratio of air permeability to basis weight, and bulk density are measured values ​​for the entire laminate. By stacking multiple nonwoven fabrics, it is possible to adjust the water resistance and moisture permeability depending on the characteristics of the nonwoven fabrics, for example, to improve water resistance while maintaining moisture permeability. The laminate may be formed by directly stacking the nonwoven fabrics, or by stacking them via an adhesive, as long as the effects of the present invention are not impaired. The laminate may also be formed by stacking nonwoven fabrics with different average fiber diameters. For example, the average fiber diameter of the nonwoven fabric with the smallest average fiber diameter may be 0.1 to 15 μm, preferably 1 to 13 μm or less. The ratio of average fiber diameters (maximum / minimum) between the nonwoven fabric with the largest average fiber diameter and the nonwoven fabric with the smallest average fiber diameter may be 1.1 to 20, preferably 1.1 to 10, and more preferably 1.1 to 5.0. By setting the ratio of average fiber diameters within this range, the fiber shape of the fibers with the larger average fiber diameter is more likely to remain when the laminate is produced by pressing, and when the nonwoven fabric layer with the larger average fiber diameter is used on the surface opposite the skin, external snagging can be reduced, making it less likely to peel off.

[0033] From the viewpoints of flexibility and skin conformability, the stress at 25% elongation of the nonwoven fabric in at least one of the plane directions may be 10 N / 5 cm or less, preferably 8 N / 5 cm or less, and more preferably 7 N / cm or less. The lower limit of the stress at 25% elongation of the nonwoven fabric is not particularly limited, but from the viewpoint of self-supporting properties, it may be 1 N / 5 cm or more, preferably 2 N / 5 cm or more, and more preferably 3 N / 5 cm or more. It is preferable that the above-mentioned stress at 25% elongation range is satisfied in two directions (e.g., MD and CD) perpendicular to the plane directions. In this specification, the stress at 25% elongation is a value measured by the method described in the Examples below.

[0034] From the viewpoint of stretchability and skin conformability, the nonwoven fabric may have an elongation of 200% or more in at least one of the plane directions, preferably 250% or more, and more preferably 280% or more. The upper limit of the elongation of the nonwoven fabric is not particularly limited, but may be, for example, 600% or less, preferably 500% or less, and more preferably 400% or less. It is preferable that the above elongation range is satisfied in two directions (e.g., MD and CD) perpendicular to the plane direction. In this specification, elongation refers to the breaking elongation in a tensile test, and is a value measured by the method described in the Examples below.

[0035] The nonwoven fabric has excellent water resistance, with a water pressure resistance of 170 mmH measured by the low water pressure method of JIS L 1092:2009. ２ 0 or more, preferably 200 mmH ２ 0 or more, more preferably 230 mmH ２ 0 or more, more preferably 280 mmH ２ The upper limit of the water pressure resistance of the nonwoven fabric is not particularly limited, but may be, for example, 1500 mmH ２ It may be O or less.

[0036] From the viewpoint of excellent self-supporting properties, the nonwoven fabric preferably has rigidity, and may have a bending resistance of 5 mm or more, for example. In this specification, the bending resistance is determined by preparing a nonwoven fabric sample with a long side of 10 cm and a short side of 2 cm so that the MD (machine direction; the direction in which the nonwoven fabric flows during production) of the nonwoven fabric is the long side and the CD (cross direction; the direction perpendicular to the MD) is the short side, placing the nonwoven fabric sample on a horizontal surface, lifting one short side end and folding it over the other short side end, and applying a load of 19 kg / m ２ The bending resistance is measured as the distance from the horizontal plane to the maximum height of the curved portion when the curved portion of the nonwoven fabric sample is formed by pressing the nonwoven fabric sample with a pressure of 1 second and then removing the load, and the curved portion is observed from the side of the nonwoven fabric sample. The higher the bending resistance, the harder the nonwoven fabric is, and the better its self-supporting properties and handling properties are. The upper limit of the bending resistance is not particularly limited, but may be, for example, 30 mm or less from the viewpoint of flexibility.

[0037] The method for measuring the bending resistance will be described in more detail using the schematic perspective views of nonwoven fabrics shown in Figures 1A, 1B, and 1C. Figure 1A shows a nonwoven fabric 10 having a long edge 11 and a short edge 12. The nonwoven fabric 10 is placed on a horizontal surface, and one short edge 12 is lifted as shown by the arrow in Figure 1A and folded over the other short edge 12. Figure 1B shows the nonwoven fabric 10 folded over with one short edge 12 over the other short edge 12. A load is then applied to a bent portion 13, which is generated approximately in the center of the long edge direction when the nonwoven fabric 10 is folded, as shown by the arrow in Figure 1B. When the load is then removed, the bent portion 13 returns to its original shape due to the rigidity of the nonwoven fabric 10, forming a curved portion 14. Figure 1C shows the nonwoven fabric 10 with the curved portion 14 formed. The vertical distance h from the horizontal plane to the maximum height of the curved portion 14 formed by the nonwoven fabric 10 can be measured as the bending resistance.

[0038] The method for producing the nonwoven fabric may include the steps of preparing a precursor nonwoven fabric and pressing the precursor nonwoven fabric. By pressing the precursor nonwoven fabric, the thickness can be reduced and the fibers can be compressed to increase their density, thereby reducing the air permeability and increasing the bulk density, depending on the pressing conditions. In order to produce the nonwoven fabric, the thickness, air permeability, and bulk density can be adjusted to the desired values ​​by adjusting the basis weight, thickness, fiber distribution, and orientation of the precursor nonwoven fabric.

[0039] The structure of the precursor nonwoven fabric is not particularly limited as long as it can produce the above-mentioned nonwoven fabric, and it may be a wet-laid nonwoven fabric, a dry-laid nonwoven fabric, or a direct-spinning nonwoven fabric (such as a spunbond nonwoven fabric or a meltblown nonwoven fabric), but a meltblown nonwoven fabric is preferred from the viewpoint of reducing the gaps between fibers and increasing the density in the subsequent pressing process.

[0040] Meltblown nonwoven fabrics are formed by discharging molten elastomer from a die, blowing a heated high-velocity airflow directly onto the die through an airflow channel built into the die, and drawing the fibrous extruded material from the die together with the high-temperature high-velocity airflow, which is then collected on a collection surface. In the meltblown method, the fiber diameter can be adjusted by controlling the die diameter, discharge rate, and collection distance from the die to the collection surface, and the basis weight and thickness can be adjusted by controlling the movement speed of the collection surface (collection speed). The basis weight and thickness of the precursor nonwoven fabric can be adjusted to achieve the desired thickness, air permeability, and bulk density in the pressing process described below. The collection speed varies depending on the fiber diameter of the fibers to be collected, but may be, for example, 5 to 30 m / min, preferably 8 to 25 m / min, and more preferably 10 to 20 m / min.

[0041] By collecting the fibrous material discharged from the die on a moving collection surface, a meltblown nonwoven fabric can be formed continuously in the machine direction (MD). The collection surface may be a porous collection surface such as a net, or may have a suction for sucking air, which can suck the airflow blown from the die and promote collection on the collection surface. The collection method may be a method using a conveyor belt for collection on a flat surface as shown in Figure 2, or a method using a rotating roll for collection on a curved surface as shown in Figures 3 and 4.

[0042] Fig. 2 is a schematic cross-sectional view showing a flat surface collection method for the melt-blowing method. In Fig. 2, fibrous extrudate 22 is discharged from a nozzle 21 together with a high-temperature, high-velocity airflow onto a collection surface 23 in a conveyor belt 24 and collected on the flat surface.

[0043] 3 and 4 are schematic cross-sectional views showing a method of collecting on a curved surface in the melt-blowing method. In Fig. 3, fibrous extrudate 32 discharged from a die 31 together with a high-temperature, high-velocity airflow is discharged onto a collection surface 33 in a rotating roll 35 and collected on the curved surface. Collection surface 33 is the outer peripheral surface of rotating roll 35, which is approximately perpendicular to the direction of extrusion from die 31.

[0044] In Fig. 4, fibrous extrudate 42 discharged together with a high-temperature, high-velocity airflow from a die 41 is discharged onto a collection surface 43 in a rotating roll 45 and collected on the curved surface. Collection surface 43 is the outer peripheral surface of rotating roll 45 located upstream of collection surface 33 in Fig. 3 in the rotation direction of rotating roll 45, and is inclined with respect to the discharge direction from die 41. The collection surface of the rotating roll can be set by the direction of the die and the positional relationship between the die and the rotating roll.

[0045] From the viewpoint of adjusting the distribution and orientation of fibers, the collection method preferably involves collecting fibers on a curved collection surface using a suction roll. By making the collection surface curved like the outer circumferential surface of the roll, the airflow blown from the die can flow along the curved shape, thereby facilitating the orientation of the accumulated fibers and ensuring a uniform distribution. By orienting the fibers and distributing them more uniformly, the density of the fibers can be increased in the pressing process described below, allowing for adjustment of the air permeability and bulk density. Furthermore, by making the collection surface the outer circumferential surface upstream of the rotation direction of the rotating roll, as shown in Figure 4, the airflow blown from the die is less likely to flow in the machine direction (the direction of rotation of the rotating roll), thereby reducing the amount of air flowing in the machine direction. This can suppress flapping of the nonwoven fabric formed by the accumulated fibers, thereby enhancing the density of the fiber structure. Furthermore, by using a suction roll to suck air, the flapping of the nonwoven fabric can be further suppressed, thereby enhancing the density of the fiber structure. Therefore, the precursor nonwoven fabric obtained at the collection position in Figure 4 can have a lower air permeability and a higher bulk density after the press treatment described below than the precursor nonwoven fabric obtained at the collection position in Figure 3.

[0046] The basis weight of the precursor nonwoven fabric is 10 to 100 g / m from the viewpoint of adjusting the breathability and bulk density of the nonwoven fabric after the press treatment. ２ and preferably 15 to 80 g / m ２ , more preferably 20 to 60 g / m ２ , more preferably 21 to 45 g / m ２ may be.

[0047] The thickness of the precursor nonwoven fabric may be 20 to 400 μm, preferably 30 to 300 μm, more preferably 40 to 200 μm, and even more preferably 50 to 100 μm, from the viewpoint of adjusting the thickness and bulk density of the nonwoven fabric after press treatment.

[0048] The average fiber diameter of the elastomer fibers constituting the precursor nonwoven fabric may be 20 μm or less, preferably 0.1 to 18 μm, and more preferably 1 to 15 μm, from the viewpoint of increasing the density of the nonwoven fabric after press treatment.

[0049] The precursor nonwoven fabric may be a precursor laminate in which a plurality of nonwoven fabrics are laminated. The precursor laminate may be a precursor laminate in which a plurality of nonwoven fabrics are simply laminated, or may be integrated by a press treatment described below. The precursor laminate is preferably a precursor laminate in which a plurality of meltblown nonwoven fabrics are laminated. In this case, the precursor laminate may be formed by separately preparing and laminating the nonwoven fabrics, or the meltblown nonwoven fabric may be used as a support and another meltblown nonwoven fabric may be formed thereon by direct spinning to form a laminate.

[0050] The precursor nonwoven fabric is then pressed to reduce its thickness and increase the density of the fibers, thereby reducing its air permeability and increasing its bulk density. The pressing process can be appropriately set depending on the structure of the precursor nonwoven fabric, and is preferably carried out continuously, for example, by a calendering process in which the fabric is compressed with a heated roll and heat treated. The heat pressing process makes it easier to deform the elastomer fibers, allowing a densely packed structure to be formed. Furthermore, the elastomer fibers can be fused together to adjust the air permeability and transparency.

[0051] When performing calendering, the linear pressure between the pair of metal rolls or between the rubber roll and the metal roll can be set appropriately depending on the thickness, basis weight, etc. of the precursor nonwoven fabric, and may be, for example, 20 to 80 kg / cm, preferably 30 to 70 kg / cm, and more preferably 35 to 60 kg / cm.

[0052] The heating temperature during calendering, which depends on the linear pressure between the rolls, can be appropriately set depending on the type of elastomeric fiber constituting the precursor nonwoven fabric in order to adjust the degree of fusion between the elastomeric fibers. In the case of urethane-based elastomeric fibers, the heating temperature of the metal roll may be, for example, 100 to 150°C, preferably 110 to 140°C, and more preferably 115 to 130°C. In the case of other elastomeric fibers, the heating temperature of the metal roll may be, for example, [Vicat softening temperature - 50°C] to [Vicat softening temperature + 50°C], where Vicat softening temperature of the elastomeric fiber constituting the precursor nonwoven fabric is measured in accordance with JIS K 7206:2016.

[0053] Nonwoven fabrics have excellent adhesion to the skin and can therefore be used as a constituent material for medical patches that are applied to the skin, wearable devices, and other patches. Examples of medical patches include wound dressings, bandages, transdermal absorbents, adhesive bandages, and medical instrument fixing materials. Examples of wearable devices include biosensors that can acquire biological information such as body temperature, blood pressure, heart rate, and electrocardiograms. In particular, nonwoven fabrics have excellent water resistance, so they can be used as a base material for wound dressings to prevent the infiltration of moisture and bacteria from the outside.

[0054] Medical patches and wearable devices preferably contain the nonwoven fabric and have the nonwoven fabric as their substrate. Furthermore, medical patches and wearable devices may include at least a substrate layer containing the nonwoven fabric and an adhesive layer containing an adhesive for use by adhering to the skin. Examples of adhesives include natural rubber-based adhesives, synthetic rubber-based adhesives, acrylic-based adhesives, styrene-isoprene (SIS) block copolymer-based adhesives, silicone-based adhesives, urethane-based adhesives, and hydrophilic adhesives. The adhesive layer can be formed by known methods, such as applying an adhesive composition containing an adhesive to a substrate or the like and drying it, or by transferring and laminating an adhesive formed by molding the adhesive composition into a predetermined shape onto a substrate or the like.

[0055] The adhesive may contain additives such as tackifiers, fillers, pigments, pH adjusters, plasticizers, antioxidants, and bioactive ingredients.

[0056] The thickness of the adhesive layer can be appropriately set depending on the application, etc., and may be, for example, about 5 μm to 200 μm from the viewpoint of adhesiveness and adhesion to the skin. The basis weight of the adhesive layer can be appropriately set depending on the application, etc., and may be, for example, 10 to 100 g / m from the viewpoint of adhesiveness and flexibility. ２ It may be to some extent.

[0057] The adhesive strength of the adhesive can be appropriately set depending on the adherend, application, etc. For example, the adhesive strength to human skin may be 0.1 to 1.0 N / 10 mm from the viewpoint of improving adhesiveness and reducing discomfort to the skin. The adhesive strength to human skin is measured with reference to 10 of JIS Z 0237:2009 "Test Methods for Adhesive Tapes and Adhesive Sheets" by using the back of a human hand as the adhesive target, degreasing with isopropyl alcohol, and then air-drying the adhesive. Furthermore, when fixing medical instruments, sensors, etc. to the skin, from the viewpoint of improving adhesiveness to these, the adhesive strength to, for example, SUS plate may be 0.1 to 10.0 N / 10 mm. The adhesive strength to SUS plate is measured in accordance with 10 of JIS Z 0237:2009 "Test Methods for Adhesive Tapes and Adhesive Sheets."

[0058] The tensile strength of the adhesive may be 0.1 to 10.0 N / 10 mm from the viewpoint of strength and flexibility as an adhesive layer. The tensile strength of the adhesive is measured in accordance with JIS Z 0237:2009 "Test methods for adhesive tapes and adhesive sheets" 8.

[0059] The moisture permeability of the adhesive is 800 to 10,000 g / m from the viewpoint of suppressing sweating of the skin. ２ The moisture permeability of the adhesive is measured in accordance with JIS Z 0237:2009 "Test methods for adhesive tapes and adhesive sheets" 15.

[0060] The adhesive layer may have a single layer structure, or may have a laminated structure in which two or more layers made of different materials or with different properties are bonded together.

[0061] The adhesive layer may have an adhesive portion and a non-adhesive portion, and the area of ​​the adhesive portion and the uneven surface structure can be designed appropriately from the viewpoint of adjusting the breathability, stretchability, water resistance, etc. of a medical patch or wearable device having an adhesive layer. The adhesive portion may have a pattern such as stripes, dots, a lattice, a rectangle, a triangle, a polygon, a circle, an ellipse, or a wave.

[0062] To improve the water resistance of the patch, the base layer or adhesive layer may be subjected to a water-repellent treatment, which may involve coating the surface of the nonwoven fabric or adhesive with a water-repellent material such as a silicone resin, a fluorine-based resin, a polystyrene resin, or an acrylic resin.

[0063] In addition to the base layer containing the nonwoven fabric and the adhesive layer containing the adhesive, the medical adhesive patch or wearable device may also include a release film or release paper to protect the adhesive layer. Examples of the release film or release paper include polyester film, polyethylene film, polypropylene film, kraft paper, and glassine paper.

[0064] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by these examples. In the following examples and comparative examples, various physical properties were measured by the following methods.

[0065] [Thickness, basis weight, bulk density] According to JIS L 1913 "General nonwoven fabric testing method" 6.1, pressing pressure: 10 g / cm ２ The thickness (mm) of the precursor nonwoven fabric and the nonwoven fabric was measured using a measuring instrument with a presser plate diameter of 16 mm. The basis weight (g / m) of the precursor nonwoven fabric and the nonwoven fabric was measured in accordance with 6.2 of JIS L 1913 "General nonwoven fabric testing method." ２ The bulk density (g / cm) of the nonwoven fabric was measured. ３ ) was calculated by dividing the basis weight by the thickness.

[0066] [Air permeability] In accordance with 8.26 of JIS L 1096 "Testing methods for woven and knitted fabrics," the air permeability (cm ) was measured by the Frazier method using an air permeability tester "FX3300" manufactured by Textest Co., Ltd. ３ / cm ２s) was measured.

[0067] [Average Fiber Diameter of Elastomer Fibers] The surface of the precursor nonwoven fabric was observed using a scanning electron microscope. The fiber diameters of 100 single fibers randomly selected from the electron microscope photograph were measured from the side to determine the number-average fiber diameter, which was taken as the average fiber diameter (μm) of the elastomer fibers.

[0068] [Water pressure resistance] The water pressure resistance (mmH) was measured in accordance with the low water pressure method of JIS L 1092:2009 "Test method for waterproofness of textile products." ２ O) was measured.

[0069] [Stress and Elongation at 25% Elongation] Tensile tests were conducted in accordance with 6.3 of JIS L 1913 "General Nonwoven Fabric Testing Methods." Five 5 cm wide, 20 cm long test pieces were prepared with the machine direction (MD) at the time of nonwoven fabric production as the longitudinal direction. Using an autograph "AGX-V" manufactured by Shimadzu Corporation, the gripping distance was set to 10 cm, and the ends of each test piece were fixed in the gripping parts of the testing machine and pulled at a rate of 200 mm / min until break. From the obtained stress-strain curve, the stress (N / 5 cm) at 25% elongation and the elongation (%) at break were calculated as average values ​​(n = 5). Similarly, the stress (N / 5 cm) at 25% elongation and the elongation (%) at break were calculated for test pieces with the cross direction (CD) as the longitudinal direction.

[0070] [Bending resistance] Five test pieces with a long side of 10 cm and a short side of 2 cm were taken from the nonwoven fabric, with the long side in the MD and the short side in the CD. The test pieces were placed on a horizontal surface, and one short side edge was lifted and folded over the other short side edge, and the bent portion was subjected to a load of 19 kg / m ２ The test piece was then pressed down for 1 second with a force of 0.05 MPa. The curved surface of the test piece formed when the load was then removed was observed from the side of the test piece, the distance (mm) from the horizontal plane to the maximum height of the curved surface was measured, and the average value (n=5) was calculated as the bending resistance (mm).

[0071] Example 1 Using a meltblown nonwoven fabric manufacturing apparatus, a polyurethane elastomer resin (KU-490 manufactured by Tosoh Corporation) was spun at a single-hole output rate of 0.3 g / min per hole (single-hole diameter: 300 μm) at a spinning temperature of 240°C, and hot air at a temperature of 240°C was blown onto the spindle, causing it to scatter and be collected on a conveyor belt at a collection speed of 14 m / min, to obtain a precursor nonwoven fabric as shown in Table 1. The obtained precursor nonwoven fabric was subjected to a calendering treatment using a rubber roll and a metal flat roll, with the metal flat roll heated to 126°C and sandwiched under a linear pressure of 50 kg / cm, to obtain a nonwoven fabric as shown in Table 1.

[0072] Example 2 A precursor nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that the single-hole discharge rate in the melt-blowing method was set to 0.2 g / min / hole, a 35 cm diameter suction roll was used for collection, the center of the discharge hole and the center of rotation of the suction roll were arranged vertically, collection was performed as shown in Figure 3, and the collection speed was set to 12 m / min. Thereafter, a nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that calendering was performed by setting the heating temperature of the metal flat roll to 120°C.

[0073] Example 3 A precursor nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that the single-hole discharge rate in the melt-blowing method was set to 0.2 g / min / hole, a 35 cm diameter suction roll was used for collection, and the collection position was arranged so that it was upstream of the rotation direction of the suction roll and 10 cm horizontally from the center of rotation, collection was performed as shown in Figure 4, and the collection speed was set to 12 m / min. Thereafter, a nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that calendering was performed with the heating temperature of the metal flat roll set to 120°C and the linear pressure between the rolls set to 50 kg / cm.

[0074] Example 4 A precursor nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that the single-hole output rate in the melt-blowing method was 0.4 g / min / hole, the spinning temperature was 250°C, and the collection speed was 11 m / min. Thereafter, a nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that calendering was performed by setting the heating temperature of the metal flat roll to 120°C.

[0075] Example 5 A meltblown nonwoven fabric shown in Table 1, produced in the same manner as in Example 1, was used as a support, and a meltblown nonwoven fabric was laminated thereon under the same conditions as in the meltblowing method of Example 1, except that the single-hole output rate was 0.5 g / min / hole, the spinning temperature was 250°C, and the collection speed was 17 m / min, to obtain a precursor laminate shown in Table 1. The obtained precursor laminate was placed so that the meltblown nonwoven fabric side having a larger average fiber diameter was in contact with a rubber roll, and the meltblown nonwoven fabric side having a smaller average fiber diameter was in contact with a metal flat roll, and the metal flat roll was heated to 126°C and sandwiched under a linear pressure of 50 kg / cm, to perform a calendering treatment, to obtain a nonwoven fabric shown in Table 1.

[0076] Example 6 A meltblown nonwoven fabric shown in Table 1, which was produced in the same manner as in Example 2 except that the collection speed was 8 m / min, was used as a support, and a meltblown nonwoven fabric was laminated thereon under the same conditions as in the meltblowing method of Example 5, to obtain a precursor laminate shown in Table 1. The obtained precursor laminate was subjected to a calendar treatment under the same conditions as in Example 5, to obtain a nonwoven fabric shown in Table 1.

[0077] Example 7 Using a meltblown nonwoven fabric manufacturing apparatus, a resin mixture of a styrene-based elastomer resin ("SEPTON 2002" manufactured by Kuraray Co., Ltd.) and a polypropylene resin ("S13BWA" manufactured by Prime Polymer Co., Ltd.) in a weight ratio of 70:30 was spun at a single-hole output rate of 0.3 g / min per hole (single-hole diameter: 300 μm) at a spinning temperature of 295°C, and hot air at a temperature of 295°C was blown onto the mixture, which was then scattered and collected on a conveyor belt at a collection speed of 10 m / min, to obtain a precursor nonwoven fabric as shown in Table 1. The obtained precursor nonwoven fabric was subjected to a calendering treatment using a rubber roll and a metal flat roll, with the metal flat roll heated to 105°C and sandwiched at a linear pressure of 50 kg / cm, to obtain a nonwoven fabric as shown in Table 1.

[0078] Example 8 A precursor nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 7, except that the collection speed in the melt-blowing method was set to 15 m / min. The obtained precursor nonwoven fabric was subjected to a calendering treatment using a rubber roll and a metal flat roll, with the metal flat roll heated to 105°C and sandwiched under a linear pressure of 50 kg / cm, to obtain a nonwoven fabric shown in Table 1.

[0079] Comparative Example 1 A precursor nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that the single-hole output rate in the melt-blowing method was 0.5 g / min / hole, the spinning temperature was 250°C, and the collection speed was 4 m / min. Thereafter, a nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that calendering was performed by setting the heating temperature of the metal flat roll to 120°C.

[0080] Comparative Example 2 A precursor nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that the single-hole discharge rate in the melt-blowing method was set to 0.2 g / min / hole and the collection speed was set to 12 m / min. Thereafter, a nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that a metal embossing roll was used instead of a metal flat roll and the heating temperature of the metal embossing roll was set to 120°C for calendaring.

[0081] Comparative Example 3 A precursor nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that the single-hole discharge rate in the melt-blowing method was set to 0.2 g / min / hole and the collection speed was set to 12 m / min. Thereafter, a nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that calendering was performed by setting the heating temperature of the metal flat roll to 100°C.

[0082] Comparative Example 4 As Comparative Example 4, a urethane film (OFU-6030B manufactured by Oishi Sangyo Co., Ltd.) shown in Table 1 was prepared and evaluated in the same manner as for the nonwoven fabric as shown in Table 1. Because Comparative Example 4 is a film, the air permeability was below the measurement limit and the water pressure resistance was above the measurement limit, and these measurement values ​​could not be detected.

[0083] Comparative Example 5 A precursor nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that the single-hole discharge rate in the melt-blowing method was set to 0.2 g / min / hole and the collection speed was set to 12 m / min. Thereafter, a nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that calendering was performed by setting the heating temperature of the metal flat roll to 105°C.

[0084] Comparative Example 6 A precursor nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that the single-hole output rate in the melt-blowing method was 0.4 g / min / hole, the spinning temperature was 245°C, and the collection speed was 24 m / min. Thereafter, a nonwoven fabric shown in Table 1 was obtained in the same manner as in Example 1, except that calendering was performed by setting the heating temperature of the metal flat roll to 122°C.

[0085]

[0086]

[0087] As shown in Table 1, the nonwoven fabrics of Examples 1 to 8 have a thickness that is thin within a specific range, and therefore when applied to the skin, the difference in level between the skin and the patch can be reduced, resulting in excellent adhesion to the skin. In addition, the ratio of air permeability to basis weight is small within a specific range, and the bulk density is high within a specific range, resulting in excellent water resistance.

[0088] On the other hand, as shown in Table 2, the nonwoven fabric of Comparative Example 1 has a relatively high water pressure resistance, but this is due to the thickness of the nonwoven fabric. When the nonwoven fabric is so thick, when it is applied to the skin, the difference in level between the skin and the patch becomes large, resulting in poor adhesion to the skin.

[0089] Furthermore, the nonwoven fabrics of Comparative Examples 2 and 3 are thin, but have poor water resistance because the ratio of air permeability to basis weight and the bulk density are not within the specified ranges.

[0090] Comparative Example 4 is a film, and therefore has low bending resistance and poor self-supporting properties.

[0091] The nonwoven fabric of Comparative Example 5 is thin and has a small ratio of breathability to basis weight, but has a low bulk density and is therefore poor in water resistance.

[0092] The nonwoven fabric of Comparative Example 6 is thin and has a high bulk density, but has a large ratio of air permeability to basis weight, and therefore is poor in water resistance.

[0093] Nonwoven fabrics can be suitably used as a constituent material for medical patches that are attached to the skin, wearable devices, and the like.

[0094] While the preferred embodiments of the present invention have been described above with reference to the drawings, those skilled in the art will readily recognize various changes and modifications within the scope of the present invention upon reading the specification. Accordingly, such changes and modifications are to be interpreted as falling within the scope of the invention as defined by the claims.

[0095] DESCRIPTION OF SYMBOLS 10: Nonwoven fabric 11: Long side end 12: Short side end 13: Bent portion 14: Curved portion 21, 31, 41: Die 22, 32, 42: Discharged material 23, 33, 43: Collection surface 24: Conveyor belt 35, 45: Rotating roll

Claims

1. A nonwoven fabric containing elastomer fibers, having a thickness of 200 μm or less and a breathability (cm ３ / cm ２ s) and basis weight (g / m ２ ) (air permeability / basis weight) is 1.0 or less, and the bulk density is 0.47 g / cm ３ That's it, nonwoven fabric.

2. The nonwoven fabric according to claim 1, having a basis weight of 10 to 100 g / m ２ That is, nonwoven fabric.

3. The nonwoven fabric according to claim 1 or 2, wherein the elastomer fiber is a urethane-based elastomer fiber.

4. The nonwoven fabric according to claim 1 or 2, wherein the stress at 25% elongation in at least one of the plane directions is 10 N / 5 cm or less.

5. The nonwoven fabric according to claim 1 or 2, wherein the elongation in at least one direction of the surface is 200% or more.

6. The nonwoven fabric according to claim 1 or 2, which has a water pressure resistance of 170 mmH as measured by the low water pressure method of JIS L 1092:2009. ２ Nonwoven fabric having a grade of O or higher.

7. The nonwoven fabric according to claim 1 or 2, wherein nonwoven fabrics having different average fiber diameters are laminated.

8. A medical adhesive patch comprising the nonwoven fabric according to claim 1 or 2.

9. The medical adhesive patch according to claim 8, which comprises an adhesive layer.

10. A wearable device comprising the nonwoven fabric according to claim 1 or 2.

11. The wearable device of claim 10, comprising an adhesive layer.

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