Laminated nonwoven fabric and wiper using the same

Abstract

The present invention provides: a laminated nonwoven fabric having a self-restoring capability; and a wiper using the same. This laminated nonwoven fabric has provided in a top outermost layer and a bottom outermost layer thereof a nonwoven fabric in which more fibers are oriented in an MD direction than in a CD direction, and that has an adhesive reinforcement layer disposed between the top and bottom outermost layers. When said laminated nonwoven fabric is subjected to a substantially U-shaped half-fold test, the number (N: number) of projecting parts formed on the inner side of the fold, the height (H: mm) of the projecting parts, and the thickness (T: mm) of the laminated nonwoven fabric, result in (H / T)×N to fall within the range of 3.9-15.0.

Description

Related Application

[0001] This application claims the priority of Japanese Patent Application No. 2020-211552 filed on December 21, 2020, and the entire disclosure of which is incorporated herein by reference and made a part of this application.

Technical Field

[0002] The present invention relates to a laminated nonwoven fabric having self-healing properties and a wiper using the same.

Background Art

[0003] In recent years, nonwoven fabrics have been increasingly used in various fields such as household goods, hygiene products, and medical products. Although nonwoven fabrics are sometimes used as disposable products, from an economic and environmental perspective, when used as wiping cloths such as industrial wipers and business-use rags, reusable nonwoven fabrics that can be washed are required.

[0004] For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-100068) discloses a bulky composite nonwoven fabric having at least three layers and having irregularities on the surface, wherein the intermediate layer of the nonwoven fabric is made of a nonwoven fabric having thermoadhesive properties, at least a part of the nonwoven fabric having thermoadhesive properties is fused, and the apparent density is 0.12 g / cm 3 A bulky composite nonwoven fabric characterized by the following is disclosed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In Patent Document 1, it is possible to obtain a bulky composite nonwoven fabric that is bulky and has excellent flexibility. However, in Patent Document 1, washing wrinkles occur in the nonwoven fabric after washing, and in the case of industrial wiping cloths, etc., it is necessary to perform an operation to stretch the deformed shape due to the washing wrinkles, and improvement of work efficiency is required.

[0007] Therefore, an object of the present invention is to provide a laminated nonwoven fabric having self-recovery property after deformation and a wiper using the same.

Means for Solving the Problems

[0008] As a result of intensive studies to achieve the above object, the inventors of the present invention found that: (i) In a nonwoven fabric having hydrophilic fibers and excellent water retention property, hydrophilic fibers are indispensable for ensuring water retention property. However, in such a nonwoven fabric, wrinkles are generated and deformed after washing due to the hydrophilic fibers, and it is necessary to perform an operation to stretch the wrinkles, resulting in a decrease in work efficiency. (ii) On the other hand, even when hydrophilic fibers are present, when the nonwoven fabric has a nonwoven fabric as the outermost layer with the reinforcing layer as the axis, when the laminated nonwoven fabric is bent, the nonwoven fabric layer of the outermost layer superposed on the bent reinforcing layer bulges as a convex portion, and the convex portion can be used as a source of repulsive force, and a nonwoven fabric having self-recovery property after deformation, which could not be obtained conventionally, can be obtained. As a result of further research, (iii) When convex portions are formed so as to have a specific relationship by a predetermined double-fold test, it becomes possible to exhibit self-recovery property after deformation, and the appearance of the laminated nonwoven fabric can be improved. (iv) In particular, when the laminated nonwoven fabric contains hydrophilic fibers, it is possible to reduce the occurrence of washing wrinkles while ensuring the water retention property by the hydrophilic fibers, and improve the work efficiency associated with washing of the laminated nonwoven fabric, leading to the completion of the present invention.

[0009] That is, the present invention can be configured in the following aspects. 〔Aspect 1〕 A laminated nonwoven fabric comprising nonwoven fabrics in which the proportion of fibers oriented in the MD direction is larger than that in the CD direction in the upper and lower outermost layers, and an adhesive reinforcing layer between the upper and lower outermost layers, When the laminated nonwoven fabric is subjected to a substantially U-shaped double-fold test, the number (N: pieces) of convex portions generated in the inner direction of the fold, the height (H: mm) of the convex portions, and the thickness (T: mm) of the laminated nonwoven fabric satisfy (H / T)×N in the range of 3.9 to 15.0. The laminated nonwoven fabric. 〔Aspect 2〕 The laminated nonwoven fabric according to Aspect 1, wherein the ratio (H / T) of the height (H: mm) of the convex portion to the thickness (T: mm) of the laminated nonwoven fabric is 1.05 to 3.00 (preferably 1.20 to 2.70, more preferably 1.30 to 2.50). The laminated nonwoven fabric. 〔Aspect 3〕 The laminated nonwoven fabric according to Aspect 1 or 2, wherein, in the folding test, the number of the convex portions is 2 to 10 pieces (preferably 3 to 9 pieces, more preferably 4 to 9 pieces). The laminated nonwoven fabric. 〔Aspect 4〕 The laminated nonwoven fabric according to any one of Aspects 1 to 3, wherein at least one of the outermost layer nonwoven fabrics is a dry nonwoven fabric of short fibers. The laminated nonwoven fabric. 〔Aspect 5〕 The laminated nonwoven fabric according to any one of Aspects 1 to 4, wherein at least one of the outermost layer nonwoven fabrics contains hydrophilic fibers and non-hydrophilic fibers. The laminated nonwoven fabric. 〔Aspect 6〕 The laminated nonwoven fabric according to any one of Aspects 1 to 5, wherein the thickness of the reinforcing layer is 0.10 to 5.00 mm (preferably 0.12 to 4.00 mm, more preferably 0.15 to 3.00 mm). The laminated nonwoven fabric. 〔Aspect 7〕 The laminated nonwoven fabric according to any one of Aspects 1 to 6, wherein the reinforcing layer has intermittent adhesiveness and has a pore structure through which liquid can permeate. The laminated nonwoven fabric. 〔Aspect 8〕 The laminated nonwoven fabric according to any one of Aspects 1 to 7, wherein the thickness (T) of the laminated nonwoven fabric is 0.5 to 5.0 mm (preferably 0.6 to 3.0 mm, more preferably 0.7 to 2.5 mm). The laminated nonwoven fabric. 〔Aspect 9〕 The laminated nonwoven fabric according to any one of Aspects 1 to 8, wherein the stiffness and softness measured by a handle-O-meter when wet is 30 to 200 g (preferably 35 to 100 g, more preferably 38 to 70 g) in at least one direction. 〔Aspect 10〕 The laminated nonwoven fabric according to any one of Aspects 1 to 8, wherein at least one outermost layer nonwoven fabric contains hydrophilic fibers / non-hydrophilic fibers in a mass ratio of 30 / 70 to 98 / 2 (preferably 40 / 60 to 96 / 4, more preferably 45 / 55 to 90 / 10). 〔Aspect 11〕 The laminated nonwoven fabric according to any one of Aspects 1 to 10, wherein at least one outermost layer nonwoven fabric contains an acrylic resin in a dry adhesion amount of 1 to 40% by mass (preferably 2 to 30% by mass, more preferably 3 to 25% by mass). 〔Aspect 12〕 The laminated nonwoven fabric according to any one of Aspects 1 to 11, wherein the reinforcing layer is composed of a reactive adhesive or a hot melt resin. 〔Aspect 13〕 The laminated nonwoven fabric according to any one of Aspects 1 to 12, wherein at least one outermost layer nonwoven fabric is a spunlace nonwoven fabric having a mesh structure. 〔Aspect 14〕 The laminated nonwoven fabric according to any one of Aspects 1 to 13, wherein at least one outermost layer nonwoven fabric has split-type conjugate fibers. 〔Aspect 15〕 The laminated nonwoven fabric according to any one of Aspects 1 to 14, which has a 3 to 5 layer structure. 〔Aspect 16〕 The laminated nonwoven fabric according to any one of Aspects 1 to 15, wherein the water retention rate is 400% or more (preferably 450% or more). 〔Aspect 17〕 A wiper composed of the laminated nonwoven fabric according to any one of Aspects 1 to 16. 〔Aspect 18〕 The wiper according to aspect 17, which has a single - leaf shape with a cut - off outer periphery, wherein the longest part A of the straight line intersecting at the center - of - gravity point in the plane direction is 10 cm to 30 cm, and the ratio A / B of the longest part A to the shortest part B is 1:1 to 2.3:1.

[0010] Here, the state where the fibers are oriented in the MD direction rather than the CD direction means that when observing the fibers on the surface of the non - woven fabric visually, the fibers on the surface of the non - woven fabric are overall oriented in the one direction (MD direction) between one direction (MD direction) and the direction orthogonal thereto (CD direction). For example, the fibers oriented in the MD direction may be oriented to intersect within the range of - 30° to + 30° with respect to a straight line parallel to the MD direction, and the fibers oriented in the CD direction may be oriented to intersect within the range of - 30° to + 30° with respect to a straight line parallel to the CD direction.

[0011] In addition, any combination of at least two components disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of the claims described in the claims is included in the present invention.

Advantages of the Invention

[0012] The laminated non - woven fabric of the present invention has a property of self - unbending or self - restoring, which causes a predetermined convex portion to be generated inside when folded in half, and can improve the aesthetic appearance of the laminated non - woven fabric. Also, even when hydrophilic fibers are present, the generation of washing wrinkles after washing can be reduced. Therefore, it can be used for various applications such as daily sundries, clothing, medical, beauty, and hygiene materials, and industrial materials, and is particularly suitable for use as a wiper (wiping cloth) such as an industrial wiper or a business - use rag that is washed and reused.

Brief Description of the Drawings

[0013] This invention will be more clearly understood from the following description of the preferred embodiments with reference to the accompanying drawings. However, the embodiments and the drawings are for illustration and explanation only and should not be used to define the scope of this invention. The scope of this invention is defined by the appended claims.

[0014]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0015] The laminated nonwoven fabric of the present invention is a laminated nonwoven fabric having nonwoven fabrics with a higher proportion of fibers oriented in the MD direction than in the CD direction in the upper and lower outermost layers, and having a reinforcing layer between the upper and lower outermost layers. When this laminated nonwoven fabric is subjected to a substantially U-shaped double-fold test, a predetermined convex portion is formed in the inner direction of the fold of the double-fold.

[0016] FIG. 1 is a schematic perspective view for explaining a measuring jig (hereinafter, may be simply referred to as a jig) used for a double-fold test for evaluating the laminated nonwoven fabric of the present invention. As shown in FIG. 1, in the present invention, as the jig 10 used for the double-fold test, a substantially U-shaped jig having a curved portion 2 is used. Specifically, the jig 10 is composed of a curved portion 2 and one straight portion 1 and the other straight portion 3 that extend from both ends of the curved portion 2 and extend parallel to each other facing each other, and has a substantially U-shaped form bent at the curved portion 2. The jig 10 is placed so that the substantially U-shaped form can be seen from above and is used for the double-fold test. The jig 10 has a length (L) of 50 mm, a width (W) of 10 mm, and a depth (D) of 30 mm on the bent inner surface. Also, if the shape of the inner surface for fixing the laminated nonwoven fabric is the same, the thickness of the jig itself is not particularly limited, but for example, it may be 1.0 mm.

[0017] FIG. 2A is a schematic side view for explaining the state of the laminated nonwoven fabric of one embodiment fixed to the measuring jig of FIG. 1, and FIG. 2B is a schematic side view for explaining the state of the measuring jig before fixing the laminated nonwoven fabric. As shown in FIGS. 2A and 2B, the curved portion 2 of the jig 10 has a semi-circular cross section with a center point C of the semi-circle, a radius of 5 mm, and a central angle of 180°, and one straight portion 1 and the other straight portion 3 extend from both ends of the semi-circle, respectively. As shown in FIG. 2A, when evaluating the laminated nonwoven fabric 20 by a double-fold test, a strip piece cut to a width of 30 mm and a length of 110 mm is cut out from the laminated nonwoven fabric. At this time, in the laminated nonwoven fabric of the present invention, since the ratio of the fibers in the outermost nonwoven fabric oriented in the MD direction is larger than that in the CD direction, the longitudinal direction of the strip piece is made to coincide with the MD direction of the outermost nonwoven fabric on the side where the convex portion is generated. Here, three strip pieces are cut out from the laminated nonwoven fabric, and the measurement is performed with n = 3.

[0018] Then, by closely attaching the laminated nonwoven fabric 20 to the inner surface of the jig 10 as much as possible, when the laminated nonwoven fabric 20 is fixed to the jig 10, in the folded inner direction of the double-folded laminated nonwoven fabric of the present invention, a predetermined convex portion is generated in the curved portion. Then, from a photograph of the state where the laminated nonwoven fabric 20 is fixed to the jig 10, the thickness of the laminated nonwoven fabric 20 and the occurrence state of the convex portion generated in the laminated nonwoven fabric are evaluated according to the following procedure.

[0019] Here, the state of being closely attached as much as possible can be evaluated as a state where a gap of 0.5 mm or more cannot be formed between the inner surface of the jig and the laminated nonwoven fabric. For example, as shown in FIGS. 4 and 5, it can be confirmed that the laminated nonwoven fabric is in close contact with the inner surface of the jig in a state where a gap of 0.5 mm or more cannot be formed with respect to the jig having a thickness of 1.0 mm.

[0020] The method of closely attaching the laminated nonwoven fabric 20 to the inner surface of the jig 10 is not particularly limited. Usually, the laminated nonwoven fabric in a state of being bent in a substantially U shape is inserted from the bent tip toward the inner surface of the jig. After the bent tip contacts the innermost side (point E) of the jig, the entire laminated nonwoven fabric is closely attached along the inner surface of the jig 10, and the nonwoven fabric is pressed in the tip direction inside the jig, whereby the laminated nonwoven fabric 20 can be closely attached to the inner surface of the jig 10 as much as possible.

[0021] First, as for the thickness of the laminated nonwoven fabric measured in the substantially U-shaped double-fold test, the thickness of the portion in contact with either the straight portion 1 or 3 of the jig 10 is measured. The thickness of the laminated nonwoven fabric 20 is selected such that the portion 7 mm advanced in the direction opposite to the curved portion 2 from the point where the perpendicular line downward from the center point C of the semi-circle intersects is taken as the first measurement location M1. When the laminated nonwoven fabric 20 has an aperture structure composed of an opening portion and a non-opening portion, the non-opening portion is selected as the first measurement location M1. If the 7-mm advanced portion is an opening portion, the nearest non-opening portion further advanced in the direction opposite to the curved portion 2 from that portion is selected as the first measurement location M1. Then, six locations are randomly selected from the non-opening portions between the first measurement location M1 and the location 12 mm advanced from M1 as the second measurement location M2 to the seventh measurement location M7, and the thicknesses of the laminated nonwoven fabric 20 at each measurement location are measured as T1 to T7, and the average value of T1 to T7 is taken as the thickness T of the laminated nonwoven fabric. Note that T1 to T7 can be measured by observing the cross-section of the sample with a digital microscope and measuring the thickness.

[0022] Figure 3 is a schematic enlarged view of the first measurement location M1 in Figure 2A enlarged. In Figure 3, a part of the fibers constituting the nonwoven fabric existing in the straight portion 1 of the laminated nonwoven fabric is schematically represented by a line. As shown in Figure 3, the thickness T1 of the laminated nonwoven fabric is measured as the distance between the intersection point I1 with the inner surface of the jig 10 and the intersection point F1 with the third fiber from the top of the laminated nonwoven fabric 20 on the perpendicular line X1 with respect to the straight portion 3 at the measurement location M1 of the thickness of the laminated nonwoven fabric 20.

[0023] Next, with reference to FIG. 2A, the height H of the convex portions of the laminated nonwoven fabric measured in a substantially U-shaped double-fold test will be described. In FIG. 2A, six convex portions P1 to P6 are present in the curved portion 2 of the jig 10. Although not shown in FIG. 2A, if convex portions are present in the straight portions 1 and 3, such convex portions are not treated as the convex portions in the present invention. In FIG. 2A, a dotted substantially C-shaped mark is attached as the range showing the curved portion 2. Also, the presence or absence of a convex portion is determined by the location of the apex of the convex portion. For example, in the case of the convex portion P1, since the apex of the convex portion P1 is present in the curved portion 2, even if a part of the convex portion P1 is present in the straight portion 1 of the jig, it is treated as the convex portion in the present invention.

[0024] For example, in FIG. 2A, in the convex portion P5 of the laminated nonwoven fabric 20, the thickness H5 is measured as the distance between the intersection point I'5 with the inner surface of the curved portion 2 and the intersection point F'5 with the third fiber from the top of the laminated nonwoven fabric 20 on the straight line R5 connecting the apex of the convex portion and the center point C of the arc (semicircle) of the curved portion 2. The height of the convex portion of the laminated nonwoven fabric 20 is measured as H1 to H6 for each of the convex portions P1 to P6 present in the curved portion, and the largest value is taken as the height H of the convex portion of the laminated nonwoven fabric.

[0025] That is, when the laminated nonwoven fabric of the present invention is subjected to a substantially U-shaped double-fold test, the number (N: pieces) of convex portions generated in the folded inner direction, the height (H: mm) of the highest convex portion, and the thickness (T: mm) of the laminated nonwoven fabric are in the range of 3.9 to 15.0 as (H / T)×N.

[0026] H / T represents the height of the highest convex portion with respect to the thickness of the laminated nonwoven fabric, and the higher the height of the convex portion, the larger the value. By dividing by the thickness of the laminated nonwoven fabric, the generalization of the laminated nonwoven fabric is performed. Since this convex portion acts to repel in the folded direction, the higher the convex portion, the higher the self-recovery property of the laminated nonwoven fabric. Also, N represents the number of convex portions, and for the same reason, the larger the number of convex portions, the higher the self-recovery property of the laminated nonwoven fabric.

[0027] For example, the ratio (H / T) with respect to the thickness (T) of the laminated nonwoven fabric may be 1.05 to 3.00, preferably 1.20 to 2.70, and more preferably 1.30 to 2.50. The ratio (H / T) only needs to be satisfied on at least one surface of the laminated nonwoven fabric, and it is preferable that both surfaces satisfy it.

[0028] The thickness (T) of the laminated nonwoven fabric can be appropriately set according to the application. For example, it may be about 0.5 to 5.0 mm, preferably 0.6 to 3.0 mm, and more preferably 0.7 to 2.5 mm.

[0029] In order to increase H / T, the outermost nonwoven fabric can be raised high. Starting from the contact point between the reinforcing layer described later existing in the laminated nonwoven fabric and the outermost nonwoven fabric (or the intermediate layer if it exists through the intermediate layer), it is possible to form a convex portion by raising the outermost nonwoven fabric from the reinforcing layer to the opposite side in the double-fold test.

[0030] Specifically, by giving the outermost nonwoven fabric appropriate flexibility, it is possible to easily form a convex portion, and as a result, H / T can be increased. When the flexibility of the outermost nonwoven fabric is too low, it tends to buckle toward the reinforcing layer side together with the reinforcing layer when folded, so it is difficult to form a convex portion by the outermost nonwoven fabric. On the other hand, when the flexibility of the outermost nonwoven fabric is too high, the inner outermost nonwoven fabric follows the deformation during folding, so it is difficult to form a convex portion.

[0031] In order to impart appropriate flexibility, it can be achieved by controlling any one or a combination of the bulk density, fiber type, and fiber-to-fiber adhesiveness of the outermost nonwoven fabric. When controlling the bulk density, in the case of a spunlace nonwoven fabric, the bulk density can be controlled by the water pressure of water entanglement, the number of treatments, and the treatment speed. Also, in the case of a needle-punched nonwoven fabric, the bulk density can be controlled by the number of needles and the number of punches. When the bulk density is high, the flexibility of the outermost nonwoven fabric tends to increase.

[0032] In addition, when using heat-fused fibers in the outermost layer to control the adhesiveness between fibers, the adhesiveness between fibers can be controlled by the type of fiber, the mixing ratio of the heat-fused fibers, the heat treatment temperature, and the treatment time. As the adhesiveness between fibers increases, the flexibility of the outermost nonwoven fabric tends to decrease. For example, when the mixing ratio of the heat-fused fibers is high, when the heat treatment temperature is high, or when the treatment time is long, the adhesiveness between fibers tends to increase.

[0033] In addition, when using a binder for the outermost nonwoven fabric, the adhesiveness between fibers can be controlled by the type of binder, the concentration and coating amount of the binder. For example, when the solid content of the binder increases, the adhesiveness between fibers increases, and the flexibility of the outermost nonwoven fabric tends to decrease.

[0034] In addition, the number of convex portions contributes to self-recovery according to the ratio (H / T) to the thickness (T) of the laminated nonwoven fabric. For example, it may be 2 to 10, preferably 3 to 9, and more preferably 4 to 9.

[0035] There is no limitation on the method for setting the number (N) of convex portions within the above range. However, the outermost nonwoven fabric (or, when an intermediate layer exists, via the intermediate layer) having intermittent adhesiveness with the reinforcing layer can control the number of convex portions. The intermittent adhesiveness is generated by the presence of adhesive regions and non-adhesive regions between the outermost nonwoven fabric (or, when an intermediate layer exists, via the intermediate layer) and the reinforcing layer. Since mainly the non-adhesive regions become convex portions, the number of convex portions can be controlled. As the size of the non-adhesive region width increases, the number of convex portions tends to decrease.

[0036] The intermittent adhesiveness may be generated by (i) controlling the outermost nonwoven fabric (or the intermediate layer when it exists) so that adhesive regions and non-adhesive regions are formed between it and the reinforcing layer, (ii) controlling the reinforcing layer so that adhesive regions and non-adhesive regions are formed between it and the reinforcing layer, or (iii) both (i) and (ii) above.

[0037] (i) When controlling the intermittent adhesiveness in the outermost nonwoven fabric, in order to impart intermittent adhesiveness, the outermost nonwoven fabric layer may be provided with unevenness. There is no limitation on the method for providing voids in the outermost nonwoven fabric layer. For example, a mesh-like support net may be provided to perform water flow entanglement, or unevenness can be provided by mesh structure or embossing structure through embossing. Also, when the support is a net, the non-adhesive area width can be controlled by changing the mesh opening, and when it is a drum, by changing the uneven pattern and interval, and when it is embossing, by changing the uneven pattern and interval. In such a case, since the adhesive area and non-adhesive area can be controlled by the outermost nonwoven fabric layer, the reinforcing layer itself does not have intermittent adhesiveness and may have overall adhesiveness.

[0038] (ii) When controlling the intermittent adhesiveness in the reinforcing layer, intermittent adhesiveness may be imparted to the reinforcing layer. For example, when applying printing, intermittent adhesiveness may be imparted to the reinforcing layer by printing an adhesive from above a mask having a desired pattern (such as dot-like, stripe-like, lattice-like, geometric pattern, etc.). Also, when applying spray, intermittent adhesiveness may be imparted to the reinforcing layer by spraying an adhesive from above a mask having a desired pattern.

[0039] (iii) When both the outermost nonwoven fabric and the reinforcing layer have intermittent adhesiveness, for example, the outermost nonwoven fabric may have an uneven structure such as a mesh structure or an embossing structure, and the reinforcing layer may have intermittent adhesiveness by spray or the like. For example, when the outermost nonwoven fabric has a mesh structure and the reinforcing layer is formed by spray, it is preferable because it is easier to generate convex portions derived from non-adhesive areas between the outermost nonwoven fabric having a mesh structure and the reinforcing layer having fine dot-like intermittent adhesiveness.

[0040] The laminated nonwoven fabric of the present invention only needs to generate a predetermined convex portion in the two-fold test on at least one side, but it is preferable to generate a predetermined convex portion in the two-fold test on both sides. Hereinafter, the laminated nonwoven fabric of the present invention will be described in more detail.

[0041] (Outermost nonwoven fabric) The laminated nonwoven fabric of the present invention includes, as the outermost layer nonwoven fabric, a nonwoven fabric having a higher proportion of fibers oriented in the MD direction than in the CD direction on the upper and lower surfaces which are the outermost layers. The nonwoven fabrics disposed on the upper and lower surfaces may be of the same type or different types from each other. Note that the MD direction is an abbreviation for the machine direction, and the CD direction is a direction orthogonal to the MD direction.

[0042] The nonwoven fabric has a higher proportion of fibers oriented in the MD direction than in the CD direction, and various nonwoven fabrics such as dry nonwoven fabrics and wet nonwoven fabrics can be used as long as they can form a predetermined convex portion. However, a dry nonwoven fabric of short fibers (non - continuous fibers) is preferable because it is easy to form convex portions. In particular, a dry nonwoven fabric using a semi - random web or a parallel web as the nonwoven fabric base is preferable.

[0043] Also, in order to form a predetermined convex portion when making a laminated nonwoven fabric, an uneven structure (preferably an uneven structure with equal intervals) may be provided on the surface of the nonwoven fabric in advance. For example, an uneven structure in the MD direction on the surface of the nonwoven fabric can be formed by using a mesh - shaped or porous support during the water - flow entanglement described later. When the laminated nonwoven fabric using such a nonwoven fabric as the outermost layer is bent, the convex portion swells due to the previously formed uneven structure, and a predetermined convex portion can be formed in a substantially U - shaped double - fold test.

[0044] The fiber length of the fibers of the nonwoven fabric may be, for example, about 20 to 80 mm, preferably about 25 to 75 mm, more preferably about 30 to 70 mm, and even more preferably about 35 to 55 mm.

[0045] From the viewpoint of ensuring softness, the fineness of the fibers (excluding split - type composite fibers) of the nonwoven fabric may be, for example, about 1.0 to 3.5 dtex, preferably about 1.3 to 3 dtex, and more preferably about 1.5 to 2.5 dtex.

[0046] The constituent fibers of the nonwoven fabric preferably include hydrophilic fibers. The hydrophilic fibers can improve the water retention of the laminated nonwoven fabric. In the present invention, the hydrophilic fiber means a fiber having a moisture regain of 4.0% or more as defined in JIS L 0105:2020.

[0047] The nonwoven fabric may preferably contain hydrophilic fibers as the main fibers (fibers that maintain their fiber shape in the nonwoven fabric). The hydrophilic fibers are not particularly limited, and natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers can be used. Also, the hydrophilic fibers may be fibers imparted with hydrophilicity by post-processing. The hydrophilic fibers may be used alone or in combination of two or more. Examples of hydrophilic natural fibers include natural cellulose fibers such as cotton, hemp, wool, and pulp. Examples of hydrophilic regenerated fibers include regenerated cellulose fibers such as rayon, lyocell such as Tencel (registered trademark), polynosic, and cupra. Examples of hydrophilic semi-synthetic fibers include semi-synthetic cellulose fibers such as acetate and triacetate. Suitable examples of hydrophilic synthetic fibers include synthetic fibers composed of a thermoplastic resin having a hydrophilic functional group such as a hydroxyl group, a carboxyl group, or a sulfonic acid group, and / or a hydrophilic bond such as an amide bond.

[0048] The hydrophilic fibers may preferably be cellulose fibers such as natural cellulose fibers, regenerated cellulose fibers, and semi-synthetic cellulose fibers. More preferably, they may be rayon fibers (e.g., viscose rayon) or solvent-spun cellulose fibers (e.g., lyocell such as Tencel) among the regenerated cellulose fibers.

[0049] The fibers constituting the nonwoven fabric include non-hydrophilic fibers. The non-hydrophilic fibers include various synthetic fibers and natural fibers. Examples of the synthetic fibers other than the hydrophilic fibers include polyolefin resins such as polyethylene and polypropylene, and polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid. Further, from the viewpoint of improving the morphological stability of the nonwoven fabric by using the thermal bonding method in addition to the chemical bonding method using a binder, for example, heat-fusible fibers may be included. The heat-fusible fibers only need to have a melting point or heat distortion temperature that can be melted at the processing temperature in thermal bonding. For example, they may be non-composite fibers of a low melting point resin having a melting point or heat distortion temperature below the processing temperature, or composite resins of the low melting point resin and a high melting point resin having a higher melting point than the low melting point resin.

[0050] In the case of composite fibers, for example, composite fibers having a core-sheath structure with a low melting point resin as the sheath component and a high melting point resin as the core component are preferable. The low melting point resin and the high melting point resin can be appropriately selected from polyolefin fibers such as polyethylene and polypropylene, and polyester fibers such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid according to the processing temperature in thermal bonding.

[0051] Further, the nonwoven fabric used in the present invention may include split-type composite fibers as ultrafine fibers. When split-type composite fibers are present, the sharp corners generated by splitting improve, for example, the dirt wiping property when used for a wiper. The split-type composite fibers that can be used in the present invention may have a single fiber fineness of 0.5 dtex or less after splitting, preferably 0.3 dtex or less, and more preferably 0.01 to 0.15 dtex. The split-type composite fibers may be split into ultrafine fibers by physical pressure such as water stream entanglement, or after forming conjugate fibers, the easily soluble component may be removed from the conjugate fibers to obtain ultrafine fibers. Such conjugate fibers may be of the side-by-side type, lemon type, or laminated type of two or more layers.

[0052] Examples of polymers used in the segmented composite fibers include polyester polymers such as polyethylene terephthalate and polybutylene terephthalate, polyolefin polymers such as polyethylene and polypropylene, polyamide polymers such as nylon 6 and nylon 66, polystyrene polymers, polyvinyl alcohol polymers, ethylene-vinyl alcohol copolymers, etc. One type or two or more types can be used for each component.

[0053] From the viewpoint of ensuring self-healing property and water retention property, among the fibers constituting the non-woven fabric, that is, the main fibers and, if necessary, the binder fibers, the ratio (mass ratio) of the hydrophilic fibers to the non-hydrophilic fibers may be 30 / 70 to 98 / 2, preferably 40 / 60 to 96 / 4, more preferably 45 / 55 to 90 / 10.

[0054] When the non-woven fabric is a chemical bond non-woven fabric, it may contain a binder as an adhesive component. Examples of the binder include acrylic resins (such as acrylic acid ester copolymer resins), polyurethane resins, vinyl acetate copolymer resins, epoxy resins, styrene resins (such as styrene-acrylic copolymer resins), etc. Preferably, it may contain at least one selected from acrylic resins, polyurethane resins, and styrene resins.

[0055] The binder may further contain at least one selected from the group consisting of a pigment, a penetrant, and a thickener, if necessary. The pigment, penetrant, and thickener can be known or conventional ones according to the purpose and configuration. When the binder contains a pigment, a desired pattern can be applied to the non-woven fabric of the present invention by partially coating the binder. As described above, the smaller the ratio of the exposed area of the binder exposed on the front and back surfaces is, the more uniform the pattern of the non-woven fabric on the front and back can be obtained, and it can be made to have excellent design properties.

[0056] From the perspective of achieving both washing durability and self - recovery, in at least one of the outermost non - woven fabric layers, the dry adhesion amount of the binder (preferably at least one selected from acrylic resins, polyurethane resins, and styrene resins) with respect to the total mass of the non - woven fabric may be 1 to 40% by mass, preferably 2 to 30% by mass, and more preferably 3 to 25% by mass.

[0057] The non - woven fabric may be a dry non - woven fabric in which a web formed from a predetermined fiber by the carding method or the air - laid method is mechanically three - dimensionally entangled by a water - jet entanglement method, a needle - punching method, etc. For example, from the perspective of imparting softness to the non - woven fabric and forming a mesh structure, it is preferably a spunlace non - woven fabric using a water - jet entanglement method for entanglement by a water - jet entanglement treatment. In the case of a chemical - bonded non - woven fabric, it can be manufactured by coating or dip - nipping a binder on at least one surface of the non - woven fabric sheet and drying the binder. The non - woven fabric sheet may be mechanically entangled in advance as necessary.

[0058] The basis weight of the non - woven fabric can be appropriately determined according to the application, and the basis weight is not particularly limited. For example, from the perspective of strength, the basis weight may be, for example, about 50 to 200 g / m 2 and preferably about 60 to 180 g / m 2 and more preferably about 70 to 160 g / m 2 The basis weight is a value measured by the method described in the examples below and includes the weight of the binder.

[0059] The thickness of the non - woven fabric can be appropriately determined according to the application, and the thickness is not particularly limited. For example, from the perspective of softness, the thickness may be, for example, about 0.1 to 2.0 mm, preferably about 0.2 to 1.5 mm, and more preferably about 0.3 to 1.0 mm. The thickness is a value measured by the method described in the examples below.

[0060] Further, from the viewpoint of improving the drying property, the nonwoven fabric preferably has a pore structure composed of openings and non-openings, and may preferably be a mesh structure or a net structure. The pore structure can be confirmed by visual observation.

[0061] (Intermediate layer) Within the range where the effects of the present invention can be exhibited, another nonwoven fabric may be present as an intermediate layer between the reinforcing layer and the outermost nonwoven fabric. In that case, the laminated nonwoven fabric has at least a three-layer structure, and may be, for example, a three to five-layer structure.

[0062] The nonwoven fabric used as the intermediate layer can be appropriately set within the range where it can be integrated with the adjacent outermost nonwoven fabric. For example, the fineness of the fibers (excluding the split-type composite fibers) constituting the intermediate layer may be, for example, about 1.0 to 3.5 dtex, preferably about 1.3 to 3 dtex, and more preferably about 1.5 to 2.5 dtex. Further, it may contain the above-described hydrophilic fibers and non-hydrophilic fibers.

[0063] When integrating the intermediate layer with the outermost nonwoven fabric, the intermediate layer and the outermost nonwoven fabric may be a laminate integrated by physical bonding (entanglement) or chemical bonding (adhesion). In this case, with the laminate as the adherend, the reinforcing layer adjacent to the adherend may be adhered.

[0064] The intermediate layer can be formed to make the laminated nonwoven fabric bulky or to increase the liquid retention amount. Depending on the purpose of the intermediate layer, the fiber type, thickness, etc. can be appropriately selected. For example, when increasing the bulkiness, the intermediate layer preferably contains the non-hydrophilic fibers described in the outermost nonwoven fabric. For example, the proportion of non-hydrophilic fibers in the intermediate layer may be 60% or more (for example, 60 to 100% by mass), preferably 70% by mass or more. Also, when increasing the liquid retention amount, the intermediate layer preferably contains the hydrophilic fibers described in the outermost nonwoven fabric. For example, the proportion of hydrophilic fibers in the intermediate layer may be 50 to 90% by mass, preferably about 60 to 80% by mass.

[0065] [Reinforcement layer] The adhesion reinforcement layer has adhesiveness, contributes to the integration of the laminated nonwoven fabric, and enables the formation of convex portions on the outermost nonwoven fabric with the reinforcement layer as the axis. The reinforcement layer only needs to exhibit adhesiveness at least between adjacent layers. For example, in the case of a three-layer structure, it has a configuration of upper nonwoven fabric / reinforcement layer / lower nonwoven fabric, and both the upper and lower nonwoven fabrics constituting the outermost layer are integrated by adhesion to the reinforcement layer.

[0066] As long as the reinforcement layer can form desired convex portions on the laminated nonwoven fabric, it may have overall adhesiveness by coating or the like, but it preferably has intermittent adhesiveness in order to easily form predetermined convex portions when made into a laminated nonwoven fabric. Intermittent adhesiveness is generated by the presence of adhesive regions and non-adhesive regions in the reinforcement layer, and as long as such a structure can be formed, it can be formed using known or conventional methods. Since the reinforcement layer has intermittent adhesiveness, when the laminated nonwoven fabric is bent, it is preferable because it is easy to form convex portions by raising the non-adhesive regions of the reinforcement layer.

[0067] The thickness of the reinforcement layer may be, for example, 0.10 to 5.00 mm, preferably 0.12 to 4.00 mm, and more preferably 0.15 to 3.00 mm. The thickness of the reinforcement layer is measured as the thickness occupied by the reinforcement layer on the perpendicular line X1 at the measurement points M1 to M7 where the thickness of the laminated nonwoven fabric is calculated, and the largest value is taken as the thickness of the reinforcement layer.

[0068] Also, since the reinforcement layer has intermittent adhesiveness, it preferably has a pore structure through which liquid can permeate. The pore structure is not particularly limited as long as liquid can pass through it. By having a pore structure through which liquid can permeate, moisture absorbed by one outermost nonwoven fabric can be moved to the other outermost nonwoven fabric through the reinforcement layer, and the water absorption of the laminated nonwoven fabric can be improved.

[0069] From the viewpoint of exhibiting adhesiveness on both sides, the reinforcement layer may be composed of a reactive adhesive or a hot melt resin agent.

[0070] As the reactive adhesive, for example, a moisture-curing adhesive that self-crosslinks by moisture in the air is preferable. Specifically, polyurethane-based resins, modified silicone-based resins, vinyl acetate-based resins, ethylene-vinyl acetate copolymers (EVA), epoxy-based resins, acrylic-based resins, synthetic rubbers (SBR), etc. can be mentioned. Among these, polyurethane-based resins are preferable.

[0071] Examples of the hot melt resin include polyolefin-based resins such as polyethylene and polypropylene, and polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid. Among these, polyolefin-based resins such as polyethylene and polypropylene are preferable.

[0072] For the reinforcing layer, the application method can be selected according to the material forming the reinforcing layer. A plurality of nonwoven fabrics with a higher proportion of fibers oriented in the MD direction than in the CD direction and, if necessary, a nonwoven fabric for the intermediate layer are prepared as the adherends. For example, in the case of a reactive adhesive, a liquid or powder adhesive is applied to the adherend surface (for example, at least one of the outermost nonwoven fabrics) by printing, spraying, etc., to bond the adherends adjacent to the reinforcing layer.

[0073] For example, when applying by printing, the adhesive may be applied in a desired pattern (for example, dot shape) to impart intermittent adhesiveness to the reinforcing layer. Also, when applying by spray, the adhesive may be applied from above a mask having a desired pattern to impart intermittent adhesiveness to the reinforcing layer. Or, in the spray itself, the droplets may be in a fine dot shape or fibrous shape, or a mixture of both, and adhere to the adherend to form an adhesive region and a non-adhesive region to impart intermittent adhesiveness to the reinforcing layer.

[0074] The proportion of the reactive adhesive in the reinforcing layer may be, for example, 3 to 35 g / m 2 and may be preferably 3 to 20 g / m 2 and more preferably 3 to 15 g / m2 It may also be.

[0075] In the case of a hot melt resin, once a web having hot melt resin fibers is formed, adjacent adherends may be adhered to each other with this adhesive web. The adhesive web may be formed of only hot melt resin fibers, or may be formed by combining hot melt resin fibers and non-hot melt resin fibers. Further, it may be formed of core-sheath fibers having a hot melt resin as a sheath component and a non-hot melt resin as a core component. In the case of the core-sheath fibers, the weight of the entire fiber is treated as a hot melt resin.

[0076] The proportion of the hot melt resin in the reinforcing layer is, for example, 3 to 35 g / m 2 and may be applied, preferably 3 to 20 g / m 2 , more preferably 3 to 15 g / m 2 and may be applied.

[0077] The laminated nonwoven fabric can be formed by subjecting a laminate having an adhesive reinforcing layer between the upper and lower outermost layers to pressure treatment or heat-pressure bonding treatment by calendar treatment according to the type of the reinforcing layer. When performing calendar treatment, the linear pressure is preferably 7 to 60 kg / cm, more preferably 10 to 45 kg / cm, and even more preferably 20 to 35 kg / cm. The laminated nonwoven fabric may further be subjected to punching or the like according to the application to obtain a desired product shape. For example, the product shape can include various shapes such as square, rectangular, circular, elliptical, heart-shaped, leaf-shaped, animal-shaped, and fish-shaped.

[0078] (Laminated nonwoven fabric) The basis weight of the laminated nonwoven fabric of the present invention may be about 100 to 400 g / m 2 and preferably about 120 to 360 g / m 2 and more preferably about 140 to 320 g / m 2 and may be about. The basis weight is a value measured by the method described in the examples described later and is a value including the weights of the binder, reinforcing layer, intermediate layer, and the like.

[0079] Also, the apparent density may be, for example, in the range of 0.05 to 0.50 g / cm 3 and preferably in the range of 0.10 to 0.40 g / cm 3 . Here, the apparent density of the laminated nonwoven fabric is the value obtained by dividing the basis weight of the laminated nonwoven fabric by the thickness. (Apparent density of nonwoven fabric (g / cm 3 ) = Basis weight (g / m 2 ) / Thickness (mm) / 1000)

[0080] The laminated nonwoven fabric of the present invention preferably has softness even when wet. For example, the stiffness-softness measured by a handle-O-meter when wet may be 30 to 200 g in at least one direction, preferably 35 to 100 g, and more preferably 38 to 70 g. The stiffness-softness when wet measured by a handle-O-meter (hereinafter sometimes referred to as WET stiffness-softness) is a value measured by the method described in the examples below.

[0081] When the laminated nonwoven fabric of the present invention contains hydrophilic fibers, it has excellent water retention properties. For example, the water retention rate of the laminated nonwoven fabric may be 400% or more, preferably 450% or more. The upper limit of the water retention rate is not particularly limited, and may be, for example, 800%. The water retention rate is a value measured by the method described in the examples below.

[0082] When the laminated nonwoven fabric of the present invention contains hydrophilic fibers, it has excellent water holding capacity. For example, the water holding amount per unit area (25 cm 2 ) of the laminated nonwoven fabric may be 1 g / 25 cm 2 or more, preferably 2 g / 25 cm 2 or more. The upper limit of the water holding amount is not particularly limited, and may be, for example, 15 g / 25 cm 2 . The water holding rate is a value measured by the method described in the examples below.

[0083] When the laminated nonwoven fabric of the present invention contains hydrophilic fibers, it is excellent in wicking (water droplets dripping are sucked into the nonwoven fabric), for example, the wicking of the laminated nonwoven fabric may be 3 seconds or less, preferably 2.5 seconds or less, particularly 1 second or less. Wicking is a value measured by the method described in the examples below.

[0084] When the laminated nonwoven fabric of the present invention contains hydrophilic fibers, it is excellent in water absorption. For example, the water uptake length measured by immersing one end of the laminated nonwoven fabric in water for 1 minute may be, for example, 40 mm or more in the longitudinal direction, preferably 50 mm or more, more preferably 60 mm or more. Also, in the transverse direction, for example, it may be 30 mm or more, preferably 40 mm or more, more preferably 50 mm or more. The uptake length is a value measured by the method described in the examples below.

[0085] Since the laminated nonwoven fabric of the present invention is excellent in self-recovery after deformation, it can be used for various applications such as household goods, clothing, medical, beauty and hygiene materials, and industrial materials. In particular, even when it contains hydrophilic fibers, it can suppress washing wrinkles after washing, so it is useful as a reusable cleaning nonwoven fabric. For example, it can be suitably used as a wiper for wiping various electrical products, furniture (e.g., tables, wardrobes, etc.), kitchen utensils (e.g., cutting boards, countertops, sinks, gas stoves, tableware, etc.), window glass, ceilings, floors, walls, etc.

[0086] When the laminated nonwoven fabric of the present invention is used as a wiper, from the viewpoint of using it without folding, it may have a single-sheet shape with a cut outer periphery. When the outer periphery is cut as it is, it is preferable because it is easy to store by stacking.

[0087] As for the size of the wiper, among the straight lines passing through the center of gravity in the plane direction, the longest length A may be 10 cm to 35 cm, preferably 13 to 30 cm. In particular, when used as a compact-sized wiper, the above-mentioned longest length A may be 10 to 20 cm, or 13 to 17 cm.

[0088] Also, from the perspective of ease of gripping, among the straight lines passing through the center of gravity in the plane direction, the ratio A / B of the longest length A to the shortest length B may be 1:1 to 2.3:1, and preferably may be 1:1 to 1:1.7.

[0089] Also, the wiper may be stacked and stored without being folded as it is after washing. Since the washing wrinkles become less noticeable over time due to self - recoverability after drying, it has excellent aesthetics. Also, due to self - recoverability, it becomes a uniform planar shape, so even when the wiper is stacked and stored, the storage thickness can be made more compact, which is preferable. Also, from the perspective of making the storage space compact, the stacked wipers may be stored vertically, and when storing, they may be stored in a vertically - placed storage case.

Example

[0090] Hereinafter, the present invention will be described in more detail 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.

[0091] [Measurement of convex portions and thickness of laminated non - woven fabric] With the MD direction of the surface for measuring the convex portions of the laminated non - woven fabric as the longitudinal direction, three strip pieces cut to a width of 30 mm and a length of 110 mm were cut out using a razor blade. Then, for each of the cut - out strip pieces, as shown in FIG. 2A, a photograph (magnification 150 times) was taken with the sample closely fixed to the measuring jig. Regarding the thickness of the laminated non - woven fabric, for all the photographs obtained for the three strip pieces, at each measurement point M1 to M7, based on the method shown in FIG. 3, the thickness of the sample was measured. Specifically, for each photograph, as the thickness of the reinforcing layer, on the perpendicular line X1 of M1 to M7, the cross - section of the sample was observed with a digital microscope, and the thicknesses T1 to T7 occupied by the reinforcing layer for each photograph were measured. T1 to T7 were averaged with n = 3. Further, the average value of the averaged T1 to T7 was taken as the thickness of the reinforcing layer. For the convex portions of the laminated nonwoven fabric, using all the photos obtained for the three strip pieces, based on the method shown in Fig. 2A, the number of convex portions generated in the curved portion of the measuring jig was counted, and the height of each convex portion was measured. Then, among the heights of the convex portions measured for each strip piece, the largest value was taken as the height H of the convex portion of each strip piece, and the average value for the three strip pieces was taken as the height H of the convex portion of the laminated nonwoven fabric. In addition, for the laminated nonwoven fabric, with the outermost nonwoven fabric layer 1 and the outermost nonwoven fabric layer 2 on the inside respectively, a substantially U-shaped double-fold test was conducted, and for each, the height H of the convex portion of the laminated nonwoven fabric was measured.

[0092] [Areal density (g / m 2 )] In accordance with 6.2 of JIS L 1913 "General Test Methods for Nonwoven Fabrics", the areal density (g / m 2 ) of the nonwoven fabric was measured.

[0093] [Apparent density (mm, g / cm 3 )] In accordance with 6.1 of JIS L 1913 "General Test Methods for Nonwoven Fabrics", with a pressing pressure of 12 g / cm 2 , using a measuring instrument with a presser plate of 1.0 inch in diameter, the thickness of the nonwoven fabric was measured, and the apparent density was calculated from this value and the areal density value.

[0094] [WET stiffness and softness] Using a Handle -O- Meter (model HOM-200, manufactured by Daiei Kagaku Seiki Co., Ltd.), the measurement size was set to 21.5 cm in length and 2.5 cm in width, and the measurement slit width was set to 1.5 cm. For the wet (WET) condition, the nonwoven fabric was in a state of retaining 300 mass% of moisture relative to the nonwoven fabric mass, and measurement was carried out with a polyethylene sheet (22 cm in length, 5 cm in width, 0.06 mm in thickness) placed under the nonwoven fabric. Measurement was performed by the handle ometer method of JIS L 1096 except that the stiffness and softness of this polyethylene sheet was set to 0.1 g.

[0095] [Wicking (seconds)] In accordance with the water absorption rate (dripping method) of JIS L 1907 7.1, water was dripped onto the test piece from a height of about 1 cm at a rate of 1 drop (about 0.05 g) using a dropper, and the average value of the time it took for the water droplet to stop reflecting peculiarly from the surface of the test piece was measured five times.

[0096] [Wicking length (mm)] In accordance with the capillary method of JIS L 1907 7.1.2, three test pieces were collected in the longitudinal and transverse directions respectively, adjusted so that the lower ends were immersed in water (2% aqueous ink solution), the height to which the water had risen after 1 minute was read, and the average value of the three was taken as the wicking length.

[0097] [Water retention (g), water retention rate (%)] Measured in accordance with the water absorption rate of JIS L 1907 7.2. The test piece was cut into a 5 cm square and its weight A (g) was measured. The test piece was immersed in water for 30 seconds. After immersion, one side of the test piece was pinched and taken out of the liquid, and the weight B (g) after 1 minute was measured as the water retention. The liquid retention rate C (%) was calculated by the following formula: C (%) = [(B - A) / A] × 100 was calculated.

[0098] [Area retention rate after washing (%)] The wiper used as a sample was spread out and placed on graph paper (SAKAE TECHNICAL PAPER A3 - 11 graph paper), photographed (FUJIFILM FINEPIX XP90) from a position 30 cm above the center height of the wiper so that the entire wiper was in the frame, and the photo was printed on A3 - sized paper (FUJI XEROX C2r). After printing, it was cut out along the contour of the wiper and weighed as weight A (g). Next, the sample was washed in accordance with the washing test conditions of JIS L 0217 103 method, placed on the above - mentioned graph paper while maintaining the shape after dehydration, photographed at the same magnification and method as the previous photographing, the photo was printed on A3 - sized paper, cut out along the contour of the wiper and weighed as weight B (g). The area retention rate of the wiper after washing (after dehydration) was determined by the following formula. Regarding the photos before and after washing, it was confirmed that they were of the same magnification using the graph paper. Area retention rate after washing (%) = (B / A) × 100 Normally, the shape of the wiper after dehydration is greatly deformed, resulting in a small area retention rate as described above. However, when the wiper has excellent self-recovery properties, due to its self-recovery properties, it is possible to approach the shape before washing even in a state where it is not completely dry after dehydration.

[0099] [Example 1] 90% by mass of rayon fiber with a fineness of 1.7 dtex and a fiber length of 40 mm ("Corona" manufactured by Daiwa Bowe Rayon Co., Ltd.), and 10% by mass of core-sheath fiber of core polyester sheath-modified polyester with a fineness of 2.2 dtex and a fiber length of 51 mm ("TJ04C2" manufactured by Teijin Limited) were uniformly mixed and carded with a semi-random card to obtain a fiber web with a basis weight of 110.0 g / m 2 The obtained fiber web was subjected to a water stream entanglement treatment. For the water stream entanglement treatment, using a nozzle with an orifice of 0.10 mm diameter provided at intervals of 0.6 mm, a 76-mesh plain-woven polyester net as a support, and using three nozzles, the water pressure of the high-pressure water stream ejected from the nozzles in the first row was 3.0 MPa, and the water pressure of the high-pressure water stream ejected from the nozzles in the second and third rows was 4.0 MPa, and it was carried out at a speed of 5 m / min. Then, the web was peeled from the support, turned inside out, and then, using a 11-mesh plain-woven polyester net as a support again, and using three nozzles, the water pressure of the high-pressure water stream ejected from the nozzles in the first row was 3.0 MPa, and the water pressure of the high-pressure water stream ejected from the nozzles in the second and third rows was 4.0 MPa, and it was carried out at a speed of 5 m / min to obtain a non-woven fabric raw fabric having a mesh structure. After drying the non-woven fabric raw fabric obtained after the above water stream entanglement treatment in a cylinder dryer to adjust the moisture content to 0% by mass, a binder (acrylic emulsion) adjusted to a solid content concentration of 10% and a viscosity of 10 mPa·s was applied by the dip nip method. Then, using a cylinder-type dryer, the surface temperature of the hot roll was set to 140 °C, and the non-woven fabric was obtained by performing drying and heat treatment several times in contact with the hot roll.

[0100] For the opposing surfaces of two pieces of this non-woven fabric, a moisture-curing type polyurethane adhesive was sprayed in a total amount of 5 g / m between the non-woven fabrics by the spray method 2After applying so as to obtain the above, the coated surfaces of the adhesive were bonded together and pressure laminated using a calendar. Next, punching was performed to a size of 18 cm in length and 23 cm in width to produce a laminated nonwoven fabric.

[0101] [Example 2] It was carried out in the same manner as in Example 1 except that the net of the support for performing the water flow entanglement treatment on the back surface was changed to a 6-mesh plain weave polyester net.

[0102] [Example 3] 50% by mass of rayon fibers having a fineness of 3.3 dtex and a fiber length of 51 mm ("Hope" manufactured by Ohmi Kenshi Co., Ltd.), 45% by mass of rayon fibers having a fineness of 1.7 dtex and a fiber length of 40 mm ("Corona" manufactured by Daiwa Bore Rayon Co., Ltd.), and 5% by mass of core-sheath fibers of core polypropylene sheath-modified polypropylene having a fineness of 2.2 dtex and a fiber length of 51 mm ("NBF(P-2)035" manufactured by Daiwa Bore Polytech Co., Ltd.) were uniformly mixed and carded with a semi-random card to obtain a fiber web having a basis weight of 75 g / m 2 Two obtained nonwoven fabrics were treated in the same manner as in Example 1 except that a moisture-curing type polyurethane adhesive was applied between the nonwoven fabrics at 10 g / m 2 by spray method.

[0103] [Example 4] 50% by mass of rayon fibers having a fineness of 1.7 dtex and a fiber length of 40 mm ("Corona" manufactured by Daiwa Bore Rayon Co., Ltd.), 30% by mass of polyester fibers having a fineness of 2.2 dtex and a fiber length of 51 mm ("TT02T" manufactured by Teijin Ltd.), and 20% by mass of core-sheath fibers of core polyester sheath polyethylene having a fineness of 2.2 dtex and a fiber length of 51 mm ("TJ04CE K" manufactured by Teijin Ltd.) were uniformly mixed and carded with a semi-random card to obtain a fiber web having a basis weight of 110.0 g / m 2 In addition, the above uniformly mixed cotton was carded with a semi-random card to obtain a fiber web having a basis weight of 75.0 g / m 2 was produced.

[0104] In addition, 100% by mass of core-sheath fibers of core polyester sheath polyethylene having a fineness of 2.2 dtex and a fiber length of 51 mm ("TJ04CE K" manufactured by Teijin Ltd.) were carded with a semi-random card to obtain a fiber web having a basis weight of 35 g / m2 A fiber web was produced. Both sides of the produced fiber web were subjected to a water stream entanglement treatment. The water stream entanglement treatment was carried out using a nozzle in which orifices with a pore diameter of 0.10 mm were provided at intervals of 0.6 mm, with a 76-mesh plain-woven polyester net as a support, using two nozzles. The water pressure of the high-pressure water stream ejected from the nozzles in the first row was 3.0 MPa, the water pressure of the high-pressure water stream ejected from the nozzles in the second row was 4.0 MPa, and it was carried out at a speed of 5 m / min. The obtained nonwoven fabric was sandwiched between two pieces of the above nonwoven fabric, and a calendar treatment was carried out at a surface temperature of 145 °C, a linear pressure of 24.8 kg / cm, and a speed of 5 m / min.

[0105] [Example 5] 20% by mass of rayon fibers with a fineness of 1.7 dtex and a fiber length of 40 mm (「Corona」 manufactured by Daiwa Bower Rayon Co., Ltd.), 40% by mass of polyester fibers with a fineness of 2.2 dtex and a fiber length of 51 mm (「TT02T」 manufactured by Teijin Limited), and 40% by mass of core-sheath fibers of core polyester sheath polyethylene with a fineness of 2.2 dtex and a fiber length of 51 mm (「TJ04CE K」 manufactured by Teijin Limited) were uniformly mixed and carded with a semi-random card to obtain a basis weight of 110.0 g / m 2 of a fiber web. A laminated nonwoven fabric was produced in the same manner as in Example 1 using two pieces of this nonwoven fabric.

[0106] [Example 6] 50% by mass of rayon fibers with a fineness of 1.7 dtex and a fiber length of 38 mm (「Lyocell」 manufactured by Lenzing AG), 30% by mass of polyester fibers with a fineness of 2.2 dtex and a fiber length of 51 mm (「TT02T」 manufactured by Teijin Limited), and 20% by mass of core-sheath fibers of core polypropylene sheath polyethylene with a fineness of 2.2 dtex and a fiber length of 51 mm (「HR-NTW」 manufactured by Ube Exsim Co., Ltd.) were uniformly mixed and carded with a semi-random card to obtain a basis weight of 110.0 g / m 2 of a fiber web. The water stream entanglement treatment was carried out in the same manner as in Example 1 to produce the outermost nonwoven fabric 1.

[0107] ​50% by mass of rayon fibers with a fineness of 1.7 dtex and a fiber length of 40 mm (Rayon "Corona" manufactured by Daiwa Bower Rayon Co., Ltd.), and 50% by mass of nylon and polyester conjugate fibers with a fineness of 3.3 dtex and a fiber length of 51 mm ("W-102" manufactured by Kuraray Co., Ltd.) were uniformly mixed and carded to obtain a fiber web with a basis weight of 28.0 g / m 2 The water jet entanglement treatment was carried out in the same manner as in Example 1, except that the water pressure of the high-pressure water jet ejected from the nozzles in the first row was 3.0 MPa and the water pressure of the high-pressure water jet ejected from the nozzles in the second row was 4.0 MPa, to produce the outermost nonwoven fabric 2.

[0108] 70% by mass of polyester fibers with a fineness of 2.2 dtex and a fiber length of 51 mm ("TT02T" manufactured by Teijin Limited), and 30% by mass of core-sheath fibers with a polyester core and a polyethylene sheath and a fineness of 2.2 dtex and a fiber length of 51 mm ("TJ04CE K" manufactured by Teijin Limited) were uniformly mixed and carded to obtain a fiber web with a basis weight of 160 g / m 2 The water jet entanglement treatment was carried out in the same manner as in Example 1. The obtained nonwoven fabric was laminated on each of the outermost nonwoven fabrics 1 and 2, and the water jet entanglement treatment was carried out in the same manner as in Example 1 to integrate them.

[0109] 100% by mass of core-sheath fibers with a polyester core and a polyethylene sheath and a fineness of 2.2 dtex and a fiber length of 51 mm ("TJ04CE K" manufactured by Teijin Limited) were carded to obtain a fiber web with a basis weight of 35 g / m 2 The water jet entanglement treatment was applied to both sides of the produced fiber web. The water jet entanglement treatment was carried out using nozzles with orifices of 0.10 mm diameter provided at 0.6 mm intervals, with a 76-mesh plain-woven polyester net as the support, using two nozzles. The water pressure of the high-pressure water jet ejected from the nozzles in the first row was 3.0 MPa, the water pressure of the high-pressure water jet ejected from the nozzles in the second row was 4.0 MPa, and the treatment was carried out at a speed of 5 m / min. The obtained nonwoven fabric was sandwiched between two sheets of the above nonwoven fabric. Three sheets of this nonwoven fabric were sprayed with a moisture-curing type polyurethane adhesive at 5 g / m 2 between the nonwoven fabrics and laminated under pressure using a calendar.

[0110] [Comparative Example 1] Using 100% by mass of rayon fibers with a fineness of 1.7 dtex and a fiber length of 40 mm (Rayon “Corona” manufactured by Daiwa Bowe Rayon Co., Ltd.), a fiber web with a basis weight of 60.0 g / m was produced using a semi-random card. 2 Next, the produced fiber web was subjected to a water entanglement treatment through a mesh drum to obtain a nonwoven fabric base fabric having a mesh structure. The moisture content of the nonwoven fabric base fabric in which the fibers were entangled by the above water entanglement treatment was adjusted to 120% by mass, and 100 g of a binder (acrylic emulsion) adjusted to a solid content concentration of 20% and a viscosity of 100 to 150 mPa·s was partially coated from one side by a printing method. Then, using a cylinder dryer, the surface temperature of the hot roll was set to 140°C, and drying was performed by bringing it into contact with the hot roll from the side opposite to the coated surface, and then drying was repeated by bringing it into contact with the hot roll from the opposite side to obtain a nonwoven fabric. Using two pieces of this nonwoven fabric, a laminated nonwoven fabric was produced in the same manner as in Example 1.

[0111] [Comparative Example 2] 90% by mass of rayon fibers with a fineness of 1.7 dtex and a fiber length of 40 mm (Rayon “Corona” manufactured by Daiwa Bowe Rayon Co., Ltd.) and 10% by mass of core-sheath fibers of core polyester sheath-modified polyester with a fineness of 2.2 dtex and a fiber length of 51 mm (“TJ-04C2” manufactured by Teijin Limited) were uniformly mixed and carded using a semi-random card to produce a fiber web with a basis weight of 110.0 g / m. 2 The water entanglement treatment was the same as in Example 1, and after reversing the front and back, it was carried out in the same manner as in Example 1 except that a 5-mesh plain-woven polyester net was used as the support again. 100% by mass of rayon fibers with a fineness of 1.7 dtex and a fiber length of 40 mm (Rayon “Corona” manufactured by Daiwa Bowe Rayon Co., Ltd.) was carded using a semi-random card to produce a fiber web with a basis weight of 120 g / m. 2 The water entanglement treatment was the same as in Example 1, and after reversing the front and back, it was carried out in the same manner as in Example 1 except that a 5-mesh plain-woven polyester net was used as the support again.

[0112] The composition of the obtained laminated nonwoven fabric is shown in Table 1, and the performance is shown in Table 2.

[0113]

Table 1

[0114]

Table 2

[0115] As shown in Table 1 and Table 2, in Examples 1 to 6, convex portions within a predetermined range are generated in all cases. The number (N: pieces) of the convex portions, the height (H: mm) of the convex portions, and the thickness (T: mm) of the laminated nonwoven fabric exist in the range of 4.5 to 11.3 as the value on the side where more are generated in terms of (H / T)×N. Therefore, they have excellent self-recovery properties. For example, as one index of self-recovery properties, the area maintenance rate after washing is 50% or more in all cases, indicating that even when washed, they are likely to maintain their original shape.

[0116] In particular, when comparing Examples 1 to 3 with Comparative Examples 1 and 2 where the stiffness and wicking are of the same degree, although both show the same degree of softness and wicking characteristics, Examples 1 to 3 are clearly less likely to generate washing wrinkles when washed compared to Comparative Examples 1 and 2, and the operation of stretching the deformed shape due to washing wrinkles can be improved.

[0117] Also, when comparing Example 3 with Comparative Example 1, although both are the following thin laminated nonwoven fabrics with a basis weight of 200 g / m 2 Example 3 can improve the area maintenance rate after washing due to the effect of the convex portions.

[0118] In Example 4, an adhesive web is used as the reinforcing layer, but the area maintenance rate after washing can be improved by controlling the shape of the convex portions as in the other examples. In particular, although the flexibility decreases compared to Examples 1 to 3 because the thickness of the reinforcing layer increases, the area maintenance rate after washing can be improved.

[0119] In Example 5, since the proportion of hydrophilic fibers is reduced, the wicking and flexibility decrease compared to Examples 1 to 3, but the area maintenance rate can be improved.

[0120] In Example 6, split fibers are used for one of the outermost nonwoven fabric layers, and since it has a five-layer structure using an intermediate layer as well, although the basis weight is large and the flexibility decreases, the water retention amount and water retention rate are improved, and the area retention rate after washing can be made extremely high.

[0121] On the other hand, when the nonwoven fabric is subjected to the double-fold test, in Comparative Example 1, although convex portions are generated but the H / T thereof is small, and in Comparative Example 2, although the H / T of the convex portions is higher than that of the examples but the number thereof is small, so (H / T)×N does not fall within the range of 3.9 to 15.0, and in both cases, the area after washing changes more greatly than in the examples, and the area retention rate after washing is not good.

Industrial Applicability

[0122] As described above, the nonwoven fabric of the present invention can be used for various applications such as daily sundries, clothing applications, medical, beauty and hygiene materials, and industrial material applications. In particular, since it is excellent in washing durability and self-recovery property, it is useful as a nonwoven fabric for cleaning that can be washed and repeatedly used. For example, it can be suitably used as a wiper used for wiping various electrical products, furniture (for example, tables, wardrobes, etc.), kitchen utensils (for example, cutting boards, cooking tables, sinks, gas stoves, tableware, etc.), as well as window glasses, ceilings, floors, walls, etc.

[0123] As described above, the preferred embodiments of the present invention have been described with reference to the drawings. However, various additions, changes or deletions are possible without departing from the spirit of the present invention, and such are also included within the scope of the present invention.

Explanation of Reference Numerals

[0124] 10 ··· Measuring jig 2 ··· Curved portion of the inner surface of the measuring jig 1, 3 ··· Straight portions of the inner surface of the measuring jig 20 ··· Laminated nonwoven fabric L ··· Length of the inner surface of the measuring jig W ··· Width of the inner surface of the measuring jig D ··· Depth of the inner surface of the measuring jig C ··· Center point of the semi - circle of the curved part on the inner surface of the measuring jig E ··· The innermost point of the curved part on the inner surface of the measuring jig P1 - P6 ··· Protrusions generated on the laminated non - woven fabric when installed on the measuring jig H5 ··· Height of the protrusion P5 generated on the laminated non - woven fabric when installed on the measuring jig R5 ··· In the protrusion P5, the radial direction from the center point C of the measuring jig towards the inner surface of the measuring jig I’5 ··· Intersection point of the radial direction R5 and the inner surface of the measuring jig F’5 ··· Intersection point of the radial direction R5 and the third fiber from the top of the laminated non - woven fabric 20 M1 - M7 ··· Measuring points of the thickness of the laminated non - woven fabric T1 ··· Thickness of the laminated non - woven fabric at the measuring point M1 X1 ··· Perpendicular line to the straight part 3 of the measuring jig at the measuring point M1 I1 ··· Intersection point of the perpendicular line X1 and the inner surface of the measuring jig F1 ··· Intersection point of the perpendicular line X1 and the third fiber from the top of the laminated non - woven fabric 20

Claims

1. A laminated nonwoven fabric comprising nonwoven fabrics with a higher proportion of fibers oriented in the MD direction than in the CD direction in the upper and lower outermost layers, and an adhesive reinforcing layer between the upper and lower outermost layers, wherein when the laminated nonwoven fabric is subjected to a substantially U-shaped double-fold test, the number of convex portions (N: pieces) generated in the folded inner direction, the height of the convex portions (H: mm), and the thickness of the laminated nonwoven fabric (T: mm) satisfy (H / T)×N in the range of 3.9 to 15.

0. The laminated nonwoven fabric.

2. The laminated nonwoven fabric according to claim 1, wherein the ratio (H / T) of the height of the convex portion (H: mm) to the thickness of the laminated nonwoven fabric (T: mm) is 1.05 to 3.

00. The laminated nonwoven fabric.

3. The laminated nonwoven fabric according to claim 1 or 2, wherein the number of the convex portions in the folding test is 2 to 10. The laminated nonwoven fabric.

4. The laminated nonwoven fabric according to any one of claims 1 to 3, wherein at least one of the outermost layer nonwoven fabrics is a dry nonwoven fabric of short fibers. The laminated nonwoven fabric.

5. The laminated nonwoven fabric according to any one of claims 1 to 4, wherein at least one of the outermost layer nonwoven fabrics contains hydrophilic fibers and non-hydrophilic fibers. The laminated nonwoven fabric.

6. The laminated nonwoven fabric according to any one of claims 1 to 5, wherein the thickness of the reinforcing layer is 0.10 to 5.00 mm. The laminated nonwoven fabric.

7. The laminated nonwoven fabric according to any one of claims 1 to 6, wherein the reinforcing layer has intermittent adhesiveness and a pore structure that allows liquid to permeate. The laminated nonwoven fabric.

8. The laminated nonwoven fabric according to any one of claims 1 to 7, wherein the thickness (T) of the laminated nonwoven fabric is 0.5 to 5.0 mm. The laminated nonwoven fabric.

9. The laminated nonwoven fabric according to any one of claims 1 to 8, wherein the stiffness and softness measured by a handle-O-meter when wet is 30 to 200 g in at least one direction. The laminated nonwoven fabric.

10. The laminated nonwoven fabric according to any one of claims 1 to 9, wherein at least one of the outermost layer nonwoven fabrics contains hydrophilic fibers / non-hydrophilic fibers in a mass ratio of 30 / 70 to 98 / 2. The laminated nonwoven fabric.

11. The laminated nonwoven fabric according to any one of claims 1 to 10, wherein at least one of the outermost layer nonwoven fabrics contains 1 to 40% by mass of an acrylic resin in terms of dry adhesion amount. The laminated nonwoven fabric.

12. A laminated nonwoven fabric according to any one of claims 1 to 11, wherein the reinforcing layer is composed of a reactive adhesive or a hot melt resin.

13. A laminated nonwoven fabric according to any one of claims 1 to 12, wherein at least one of the outermost nonwoven fabrics is a spunlace nonwoven fabric having a mesh structure.

14. A laminated nonwoven fabric according to any one of claims 1 to 13, wherein at least one of the outermost nonwoven fabrics has split conjugate fibers.

15. A laminated nonwoven fabric according to any one of claims 1 to 14, having a 3- to 5-layer structure.

16. A laminated nonwoven fabric according to any one of claims 1 to 15, having a water retention rate of 400% or more.

17. A wiper composed of the laminated nonwoven fabric according to any one of claims 1 to 16.

18. The wiper according to claim 17, having a single-sheet shape with a cut outer periphery, wherein the longest part A of a straight line intersecting at the center of gravity in the plane direction is 10 cm to 30 cm, and the ratio A / B of the longest part A to the shortest part B is 1:1 to 2.3:1.

Images