Dispersible non-woven fabric

Abstract

The embodiment of the invention provides a dispersible non-woven fabric which comprises a body, the body comprises at least two base layers combined through embossing, the weight of each base layer is smaller than or equal to 50 g / m < 2 >, each base layer comprises inner surfaces facing each other, embossing units are formed on the inner surfaces, and the embossing units are arranged on the inner surfaces. Each embossing unit comprises first linear embossments and second linear embossments which are alternately arranged, the first linear embossments and the second linear embossments are wavy, the first linear embossments on the adjacent base layers are staggered in arrangement, the second linear embossments on the adjacent base layers are staggered in arrangement, and the first linear embossments on the adjacent base layers are staggered in arrangement. By means of the arrangement, on one hand, the effect of a high-gram-weight non-woven fabric can be achieved through an existing low-gram-weight non-woven fabric, and on the other hand, by means of the arrangement mode, the dispersing performance of the non-woven fabric capable of being dispersed can be greatly improved, and the non-woven fabric capable of being dispersed is equivalent in strength and larger in thickness.

Description

TECHNICAL FIELD

[0001] The present application relates to a flushable non-woven fabric. BACKGROUND

[0002] Flushable non-woven fabric, as a material that takes into account the convenience of modern life and environmental protection, has shown great application prospects in many fields such as wet wipes, sanitary products, medical dressings, etc. The core technical challenge is to meet the strength and toughness required in the production and use process, and to ensure that the product can disperse quickly and completely in water after use, so as to avoid clogging the drainage system. These two performance indicators, strength and flushability, present a significant and difficult to reconcile internal contradiction in material science and engineering practice.

[0003] Since strength is directly related to basis weight, in order to better balance strength and flushability, the currently widely used flushable non-woven fabric is usually 45-75 g / m2. However, people want to apply flushable non-woven fabric to more extensive occasions, such as when used as a face towel or a wiping towel, people also want it to have a thicker thickness. The more direct means to increase thickness is to increase basis weight, such as increasing basis weight to more than 90 g / m2, which can get a more satisfactory thickness. However, increasing basis weight will directly increase strength, making it difficult to meet the requirements of dispersion performance.

[0004] In document CN120867009A, it is proposed that by means of structural reconstruction, i.e. by secondary drying to induce a fluffy weakening structure in the corresponding area of the wetting point, and by local precise wetting and secondary drying to induce a fluffy structure, so that a high-basis-weight flushable non-woven fabric of more than 85 g / m2 can balance the strength retention and rapid dispersion ability of the non-woven fabric.

[0005] However, this method requires the use of high-precision dot matrix liquid spraying, more specifically, the use of expensive piezoelectric nozzles combined with high-precision vision systems to achieve high-precision liquid spraying, which significantly increases equipment investment and maintenance costs. Therefore, a new technical solution is needed to solve the above technical problems. SUMMARY

[0006] The technical problem solved by the present application is the contradiction between high strength and rapid flushability of traditional high-basis-weight non-woven fabric, and the low dispersion efficiency and complex process of existing technology.

[0007] A washable nonwoven fabric includes a body, the body comprising at least two base layers bonded by embossing, each base layer having a basis weight of less than or equal to 50 g / m², each base layer comprising inner surfaces facing each other, wherein embossed units are formed on the inner surfaces, each embossed unit comprising a first linear embossing and a second linear embossing arranged in an alternating manner, wherein both the first linear embossing and the second linear embossing are wavy lines, and the first linear embossing on adjacent base layers is staggered in arrangement.

[0008] In one embodiment, the first linear embossing includes a plurality of first curved segments arranged in sequence. The first curved segments include a first arc segment, a second arc segment, a third arc segment located between the first arc segment and the second arc segment, a first straight segment connecting the first arc segment and the third arc segment, and a second straight segment connecting the second arc segment and the third arc segment. The curvature direction of the third arc segment is opposite to that of the first arc segment and the second arc segment, and the curvature of the first arc segment and the second arc segment is the same.

[0009] In one embodiment, the first arc segment, the second arc segment, and the third arc segment are all circular arc segments. At the same time, the first straight line is tangent to the first arc segment and the third arc segment, and the second straight line is tangent to the second arc segment and the third arc segment.

[0010] In one embodiment, the first centerline is defined as a virtual straight line passing through the midpoint of the third arc segment on the corresponding first curve segment of the adjacent first linear embossing. Then, the first arc segment and the second arc segment are symmetrical along the first centerline, the first straight line and the second straight line are symmetrical along the first centerline, and the third arc segment itself is symmetrical along the first centerline.

[0011] In one embodiment, the first centerline is perpendicular to the MD direction or CD direction of the body.

[0012] In one embodiment, the second linear embossing is located between adjacent first linear embossings. The second linear embossing includes a plurality of second curved segments arranged sequentially. Each second curved segment includes a fourth arc segment, a fifth arc segment, a sixth arc segment located between the fourth and fifth arc segments, a third straight segment connecting the fourth and fifth arc segments, and a fourth straight segment connecting the fifth and sixth arc segments. The bending direction of the sixth arc segment is opposite to that of the fourth and fifth arc segments, and the bending direction of the sixth arc segment is the same as that of the third arc segment. Furthermore, the curvatures of the fourth and fifth arc segments are the same.

[0013] In one embodiment, the fourth, fifth, and sixth arc segments are all circular arc segments. At the same time, the third straight line is tangent to the fourth and sixth arc segments, and the fourth straight line is tangent to the fifth and sixth arc segments. Furthermore, the curvature of the fourth and fifth arc segments is greater than the curvature of the first and second arc segments, and the curvature of the sixth arc segment is greater than the curvature of the third arc segment.

[0014] In one embodiment, the minimum spacing between the first linear embossing and the second linear embossing is less than 15 mm.

[0015] In one embodiment, the first linear embossing is formed by adjacent dot-shaped indentations, and all the dot-shaped indentations constituting the first linear embossing are directional indentations, each directional indentation including a pointing direction. Each dot-shaped indentation includes an edge line, each edge line including a large end and a small end, both the large end and the small end being arcs, with the radius of the large end being greater than the radius of the small end. Furthermore, the length of the dot-shaped indentation is greater than the sum of the radii of the large end and the small end, and the ratio of the length to the width of the dot-shaped indentation is less than or equal to 5.

[0016] In one embodiment, in the first embossing unit, the dotted indentations in adjacent first linear embossing units point in opposite directions.

[0017] Beneficial Effects: This invention provides a washable nonwoven fabric, comprising a body, the body comprising at least two base layers bonded by embossing, each base layer having a basis weight of less than or equal to 50 g / m², each base layer comprising inner surfaces facing each other, on which embossing units are formed, each embossing unit comprising a first linear embossing and a second linear embossing arranged in an alternating manner, wherein both the first and second linear embossings are wavy lines, and the first linear embossings on adjacent base layers are staggered in arrangement. This arrangement achieves the effect of a high basis weight nonwoven fabric by using existing low basis weight washable nonwoven fabrics, and simultaneously, this arrangement can significantly improve dispersion performance, while maintaining comparable strength and a thicker washable nonwoven fabric. Attached Figure Description

[0018] Figure 1 Schematic diagram of the washable nonwoven fabric according to an embodiment of the present invention; Figure 2 for Figure 1 Schematic diagram of the cross section at point AA; Figure 3 This is a schematic diagram of the first embossed unit on the first base layer; Figure 4 for Figure 3 Enlarged diagram of area B in the middle; Figure 5 A schematic diagram of dot-shaped indentations used to form the first linear embossing; Figure 6 This is a schematic diagram of the second embossed unit on the second base layer; Illustrated component symbols: Body 10; First base layer 11; First surface 11a; Second surface 11b; Third surface 12a; Fourth surface 12b; First embossing unit 110; First linear embossing 111, 111', 211; First center line 100; First curved segment 1110; First arc segment 1111; Second arc segment 1112; Third arc segment 1113; First straight segment 1114; Second straight segment 1115; Second linear embossing 112, 112', 212; Second curved segment 1120 1120; Fourth arc segment 1121; Fifth arc segment 1122; Sixth arc segment 1123; Third straight segment 1124; Fourth straight segment 1125; Interval zone 1100; First zone 1101; Second zone 1102; Third zone 1103; Fourth zone 1104; Second base layer 12; Second embossing unit 120; Combined embossing 13; Dotted indentation 20; Large end 21; Small end 22. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this invention.

[0020] See Figures 1-6 This invention provides a washable nonwoven fabric, including a body 10, wherein the body 10 includes at least two base layers, and the two base layers are bonded together by embossing.

[0021] The base layer is a washable material, with a basis weight of less than or equal to 50 g / m². Typically, the base layer comprises natural fibers and regenerated fibers, which are interwoven to form a sheet-like material. The natural fibers can be at least one of wood pulp fiber, bamboo fiber, straw pulp fiber, sugarcane pulp fiber, and cotton pulp fiber. Preferably, the length of the natural fibers is less than 10 mm; more preferably, fibers with good water dispersibility, i.e., water-dispersible fibers, are used. Here, water dispersibility refers to a property that allows the fibers to separate when in contact with a large amount of water. Furthermore, fiber length refers to the average fiber length. Specifically, the natural fiber is wood pulp fiber. Preferably, the natural fiber is wood pulp fiber with a fiber length of 1.5 to 6.5 mm. In addition, since coniferous wood pulp fiber has better water dispersibility and longer length, it is preferred that the wood pulp fiber is coniferous wood pulp fiber.

[0022] Regenerated and natural fibers are intertwined, and the finer the fibers, the easier it is to disperse the base layer. Preferably, the denier of the regenerated fibers is 12 denier or less, more preferably 7 denier or less, and the aspect ratio of the regenerated fibers is 400 to 14000, where the aspect ratio is equal to (fiber length ÷ denier) × 1000. In other specific embodiments, the mass ratio of natural fibers to regenerated fibers is 9:1 to 1:2, preferably 7:3 to 2:1. Preferably, the regenerated fibers include a first regenerated fiber and a second regenerated fiber, so that the base layer can simultaneously meet the requirements of strength and water dispersibility. Typically, the first regenerated fiber and the second regenerated fiber can be two types of fibers with different lengths or two types of fibers with different shapes. Relatively longer fibers can give the base layer higher strength, while relatively shorter fibers are easier to disperse. In addition, fibers with different shapes also have different strengths and water dispersibility. When the first regenerated fiber and the second regenerated fiber are two types of fibers with different lengths, the length of the first regenerated fiber can be 3-12 mm. The length of the second regenerated fiber can be 6-20 mm. Preferably, the regenerated fiber is viscose fiber. When the regenerated fiber is viscose fiber, the viscose fiber is at least one of flat viscose fiber and round viscose fiber.

[0023] Flat viscose fibers can be obtained by dissolving natural fibers in a suitable solvent and then wet spinning them. Compared to round viscose fibers, flat viscose fibers have lower bending stiffness and are more prone to entanglement. Typically, fibers in the base layer can entangle using their own physical properties, and this entanglement is a frictional cohesion process. Understandably, because flat viscose fibers require less external force to achieve entanglement compared to round viscose fibers, they are more easily dispersed in water. Therefore, if the base layer contains too many flat viscose fibers, prolonged immersion in the solution can easily lead to dispersion, resulting in poor applicability of the nonwoven fabric. Therefore, viscose fibers contain both flat and round viscose fibers. Preferably, the first regenerated fiber is a flat viscose fiber, and the second regenerated fiber is a round viscose fiber, with a mass ratio of 7:3 to 3:7, more preferably 7:3 to 1:1.

[0024] In addition to natural and regenerated fibers, the base layer may also contain other fibers, such as chemical fibers, synthetic fibers like polypropylene, polyvinyl alcohol, polyester, and polyacrylonitrile, or synthetic pulp composed of biodegradable synthetic fibers or polyethylene. Furthermore, fibers that have undergone microfibrillation on the surface of regenerated cellulose fibers can be added; that is, rayon fibers with submicron-sized fine fibers peeled off from the surface of the aforementioned fibers. Preferably, the added fibers are biodegradable fibers that allow the nonwoven fabric to decompose even when discarded in nature. When other fibers are present, their mass in the base layer should be less than or equal to 10%, more preferably less than or equal to 7%.

[0025] In one specific embodiment, the base layer can be formed in the following manner: S101: Provide fiber raw materials, wherein the fiber raw materials are the aforementioned natural fibers and regenerated fibers, wherein the natural fibers account for 60-80% of the fiber raw materials. The regenerated fibers can be lyocell fibers, with a length range of 8-15 mm, a linear density controlled between 1.2-1.8 denier, and a proportion of 20-40%. Lyocell fibers have excellent wet strength and biodegradability, which helps to improve the washability of the product. It is understood that the length is the average length, and the linear density is the average linear density.

[0026] Understandably, the choice of fiber raw materials can be adjusted according to specific application requirements.

[0027] S102: Fiber web formation.

[0028] The fiber web forming process can be carried out using a wet web forming method. During the web forming process, the basis weight of the fiber web is controlled within the range of 25 to 50 grams per square meter, and the web forming speed is maintained at 50 to 200 meters per minute.

[0029] S103: Hydroentangled reinforcement.

[0030] The fiber web is reinforced using a hydroentangling device equipped with multiple rows of high-pressure water jet beams. The water jet diameter is controlled within the range of 0.1–0.15 mm, and the water pressure is set to 20–80 bar. The water jets are arranged in 3–5 rows in a staggered pattern to ensure that every area of ​​the fiber web receives uniform hydroentangling impact. The impact of the high-pressure water flow causes the fibers to entangle with each other, forming a stable network structure. This hydroentangling reinforcement process improves the mechanical strength of the base layer.

[0031] S104: Drying to form the base layer.

[0032] During the first drying cycle, the drying temperature should be controlled within the range of 80 to 140°C, the drying time should be 0.5 to 5 minutes, and the final moisture content should be reduced to below 8%.

[0033] The two base layers are bonded together by embossing. An embossed pattern can be formed on the body 10 using an embossing roller assembly, thereby bonding the two base layers together. Specifically, the body 10 includes a first base layer 11 and a second base layer 12. The embossing roller assembly includes an upper roller and a lower roller, with a gap between the upper and lower rollers. The upper roller is provided with several embossing protrusions. When the body 10 passes through the gap, the embossing protrusions apply pressure to the first base layer 11 and / or the second base layer 12, causing some fibers between the first base layer 11 and the second base layer 12 to become entangled, thereby bonding the first base layer 11 and the second base layer 12 together. At the same time, a bonding embossing 13 is formed on the first base layer 11 and / or the second base layer 12, bonding the first base layer 11 and the second base layer 12 together.

[0034] In this embodiment, the first base layer 11 includes a first surface 11a and a second surface 11b, and the second base layer 12 includes a third surface 12a and a fourth surface 12b. The first surface 11a and the third surface 12a form mutually facing inner surfaces. That is, in the body 10, the first surface 11a and the third surface 12a are in a face-to-face fit. Meanwhile, embossing units are provided on the first surface 11a and the third surface 12a. The embossing units include a first linear embossing (111, 121) and a second linear embossing (112, 122) arranged in an alternating manner. The first linear embossing (111, 121) and the second linear embossing (112, 122) are both wavy lines, and the first linear embossing (111, 121) on adjacent base layers are staggered in arrangement.

[0035] Specifically, a first embossing unit 110 is provided on the first surface 11a, and a second embossing unit 120 is provided on the third surface 12a. The first embossing unit 110 includes a first linear embossing 111 and a second linear embossing 112. The second embossing unit 120 also includes a first linear embossing 121 and a second linear embossing 122. The first linear embossing 121 of the second embossing unit 120 is basically the same as the first linear embossing 111 of the first embossing unit 110, and the second linear embossing 112 of the second embossing unit 120 is basically the same as the second linear embossing 112 of the first embossing unit 110.

[0036] Please refer to this as well. Figure 3 and Figure 4 ,exist Figure 3 The image shows the first embossed unit 110 on the first base layer 11. Figure 4The image shows an enlarged view of a portion of the first embossing unit 110. In the first embossing unit 110, the first linear embossing 111 and the second linear embossing 112 are arranged alternately. The alternating arrangement means that the first linear embossing 111 and the second linear embossing 112 are arranged in the form of first linear embossing 111, second linear embossing 112, first linear embossing 111', second linear embossing 112', and so on. At the same time, the distance between the sequentially arranged first linear embossing 111 and the distance between the sequentially arranged second linear embossing 112 are equal. Both the first linear embossing 111 and the second linear embossing 112 are wavy lines.

[0037] Furthermore, the first linear embossing 111 includes a plurality of first curved segments 1110 arranged in sequence. Each first curved segment 1110 includes a first arc segment 1111, a second arc segment 1112, a third arc segment 1113 located between the first arc segment 1111 and the second arc segment 1112, a first straight segment 1114 connecting the first arc segment 1111 and the third arc segment 1113, and a second straight segment 1115 connecting the second arc segment 1112 and the third arc segment 1113. The curvature direction of the third arc segment 1113 is opposite to that of the first arc segment 1111 and the second arc segment 1112, so that the first arc segment 1111 and the second arc segment 1112 appear as peaks in the wavy line, and the third arc segment 1113 appears as a trough in the wavy line. At the same time, the curvature of the first arc segment 1111 and the second arc segment 1112 is the same.

[0038] Furthermore, the first arc segment 1111, the second arc segment 1112, and the third arc segment 1113 are all circular arc segments. At the same time, the first straight line is tangent to the first arc segment 1111 and the third arc segment 1113, and the second straight line is tangent to the second arc segment 1112 and the third arc segment 1113.

[0039] Understandably, by setting up an equal-width interval 1100 between adjacent first linear embossing 111, if a first center line 100 is defined as a virtual straight line passing through the midpoint of the third arc segment 1113 on the adjacent first curve segment 1110, then the first arc segment 1111 and the second arc segment 1112 are symmetrical along the first center line 100, the first straight line and the second straight line are symmetrical along the first center line 100, and the third arc segment 1113 itself is symmetrical along the first center line 100.

[0040] Furthermore, the first centerline 100 is perpendicular to the MD or CD direction of the body 10, so that the extension direction of the first linear embossing 111 is always inclined to the CD direction of the body 10, thereby preventing the first linear embossing 111 from having a significant impact on the strength of the first base layer 11.

[0041] Understandably, the second linear embossing 112 is located between adjacent first linear embossing 111. Simultaneously, the second linear embossing 112 includes a plurality of second curved segments 1120 arranged sequentially. Each second curved segment 1120 includes a fourth arc segment 1121, a fifth arc segment 1122, a sixth arc segment 1123 located between the fourth arc segment 1121 and the fifth arc segment 1122, a third straight segment 1124 connecting the fourth arc segment 1121 and the fifth arc segment 1122, and a connecting line segment 1124. The fourth straight line segment 1125 of the fifth arc segment 1122 and the sixth arc segment 1123, and the curvature direction of the sixth arc segment 1123 are opposite to those of the fourth arc segment 1121 and the fifth arc segment 1122, so that the fourth arc segment 1121 and the fifth arc segment 1122 appear as wave peaks in the wavy line, and the sixth arc segment 1123 appears as a wave trough in the wavy line. In addition, the curvature direction of the sixth arc segment 1123 is the same as that of the third arc segment 1113, and the curvature of the fourth arc segment 1121 and the fifth arc segment 1122 is the same.

[0042] Furthermore, the fourth arc segment 1121, the fifth arc segment 1122, and the sixth arc segment 1123 are all circular arc segments. At the same time, the third straight line is tangent to the fourth arc segment 1121 and the sixth arc segment 1123, and the fourth straight line is tangent to the fifth arc segment 1122 and the sixth arc segment 1123. The peaks and troughs of the second linear embossing 112 correspond to those of the first linear embossing 111. Moreover, the curvature of the fourth arc segment 1121 and the fifth arc segment 1122 is greater than that of the first arc segment 1111 and the second arc segment 1112, and the curvature of the sixth arc segment 1123 is greater than that of the third arc segment 1113, so that the second linear embossing 112 presents a higher peak and trough.

[0043] Furthermore, if the second centerline is defined as a virtual straight line passing through the midpoint of the sixth arc segment 1123 on the adjacent second curve segment 1120, then the second centerline coincides with the first centerline 100.

[0044] Understandably, the second linear embossing 112 actually divides the interval 1100 into an upper and lower half. On either side of each first center line 100 are the first half, 1101 and 1103, and the second half, 1102 and 1104, respectively. The first half, 1101, 1102, 1103, and 1104 all exhibit a gradually increasing pattern from one end to the other. Specifically, the first half, 1101, presents… The spacing between the first linear embossing 111 and the second linear embossing 112 gradually increases from the direction away from the first center line 100 toward the first center line 100. In the second zone 1102, the spacing between the first linear embossing 111 and the second linear embossing 112 gradually increases from the direction away from the first center line 100 toward the direction away from the first center line 100. The third zone 1103 has the same appearance as the first zone 1101, and the fourth zone 1104 has the same appearance as the second zone 1102.

[0045] Furthermore, the minimum distance between the first linear embossing 111 and the second linear embossing 112 is less than 15 mm. More preferably, the minimum distance between the first linear embossing 111 and the second linear embossing 112 is 8-12 mm. This allows the liquid to diffuse more quickly through the bridging effect between the long fibers during the diffusion process, while also preventing strength loss caused by the squeezing effect between the fibers.

[0046] The study found that, through the above-mentioned setup, on the one hand, by setting the first linear embossing 111 and the second linear embossing 112 in a wavy pattern on the opposing surfaces, water can be quickly guided through the interface into the space between the two substrates, creating a separation effect. Simultaneously, the wavy pattern reduces the mutual influence of surface tension during liquid diffusion, facilitating substrate separation. On the other hand, the wavy first linear embossing 111 and the second linear embossing 112 avoids direct indentation in the MD or CD direction, preventing excessive loss of material strength. Furthermore, the staggered wavy lines between the two substrates further weaken the strength loss in the MD or CD direction, avoiding the formation of direct weakening points that could affect the performance of the body 10 during use. Unexpected damage occurred during the process. In further research, when the first zone 1101, the second zone 1102, the third zone 1103, and the fourth zone 1104 all exhibit a shape that gradually increases from one end to the other, it is possible to create a weakened zone at the adjacent near point during the liquid wetting process, increasing the peeling effect of the water flow and making it easier to form a scattering effect. In particular, when the minimum spacing between the first linear embossing 111 and the second linear embossing 112 is 8-12 mm, under the condition of basically the same basis weight, compared with a single-layer high basis weight scatterable nonwoven fabric using the same material and the same preparation process, the strength is only reduced by about 2-7%, but the scatterability is improved by 35-45%, and the thickness is increased by 3-12%.

[0047] Understandably, the wavy lines intersecting between the two base layers refer to the first linear embossing in the first embossing unit 110 and the first linear embossing in the second embossing unit 120 being intersected. The intersecting means that the peaks of the first linear embossing in the first embossing in the first embossing unit 110 and the peaks of the first linear embossing in the second embossing unit 120 are intersected, and the peaks of the first linear embossing in the first embossing in the first embossing in the first embossing in the first embossing in the first embossing in the second embossing unit 120 are located in the trough area of ​​the first linear embossing in the second embossing unit 120.

[0048] Furthermore, the first linear embossing is formed by adjacent dot-shaped indentations 20, and all the dot-shaped indentations 20 constituting the first linear embossing are directional indentations. The term "directional indentation" refers to the dot-shaped indentations 20 having a directional direction. Please refer to this information. Figure 5 ,exist Figure 5 The diagram shows the directional dotted indentations 20 that constitute the first linear embossing.

[0049] The directional dotted indentation 20 refers to a dotted indentation 20 having the following shape: the dotted indentation 20 includes an edge line, the edge line includes a large end 21 and a small end 22, the large end 21 and the small end 22 are both arcs, and the radius of the large end 21 is greater than the radius of the small end 22, and the length of the dotted indentation 20 is greater than the sum of the radii of the large end 21 and the small end 22, and the length-to-width ratio of the dotted indentation 20 is less than or equal to 5.

[0050] Furthermore, in the first embossing unit 110, the dot-shaped indentations 20 in adjacent first linear embossings point in opposite directions to better guide the liquid into the interface between the substrates from different directions, and make the body 10 easy to separate from the interface.

[0051] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A washable nonwoven fabric, comprising a body, characterized in that, The main body comprises at least two base layers bonded together by embossing, each base layer having a base weight of less than or equal to 50 g / m². Each base layer comprises inner surfaces facing each other, on which embossed units are formed. Each embossed unit comprises a first linear embossing and a second linear embossing arranged in an alternating manner. Both the first and second linear embossings are wavy lines, and the first linear embossings on adjacent base layers are staggered in arrangement.

2. The washable nonwoven fabric as described in claim 1, characterized in that, The first linear embossing includes a plurality of first curved segments arranged in sequence. Each first curved segment includes a first arc segment, a second arc segment, a third arc segment located between the first and second arc segments, a first straight segment connecting the first and third arc segments, and a second straight segment connecting the second and third arc segments. The curvature direction of the third arc segment is opposite to that of the first and second arc segments, and the curvature of the first and second arc segments is the same.

3. The washable nonwoven fabric as described in claim 2, characterized in that, The first, second, and third arc segments are all circular arc segments. At the same time, the first straight line is tangent to the first and third arc segments, and the second straight line is tangent to the second and third arc segments.

4. The washable nonwoven fabric as described in claim 3, characterized in that, Define the first centerline as a virtual straight line passing through the midpoint of the third arc segment on the corresponding first curve segment of the adjacent first linear embossing. Then, the first arc segment and the second arc segment are symmetrical along the first centerline, the first straight line and the second straight line are symmetrical along the first centerline, and the third arc segment itself is symmetrical along the first centerline.

5. The washable nonwoven fabric as described in claim 4, characterized in that, The first centerline is perpendicular to the MD or CD direction of the body.

6. The washable nonwoven fabric as described in claim 5, characterized in that, The second linear embossing is located between adjacent first linear embossings. The second linear embossing includes a plurality of second curved segments arranged sequentially. Each second curved segment includes a fourth arc segment, a fifth arc segment, a sixth arc segment located between the fourth and fifth arc segments, a third straight segment connecting the fourth and fifth arc segments, and a fourth straight segment connecting the fifth and sixth arc segments. The bending direction of the sixth arc segment is opposite to that of the fourth and fifth arc segments, and the bending direction of the sixth arc segment is the same as that of the third arc segment. Furthermore, the curvatures of the fourth and fifth arc segments are the same.

7. The washable nonwoven fabric as described in claim 6, characterized in that, The fourth, fifth, and sixth arc segments are all circular arc segments. At the same time, the third straight line is tangent to the fourth and sixth arc segments, and the fourth straight line is tangent to the fifth and sixth arc segments. Furthermore, the curvature of the fourth and fifth arc segments is greater than the curvature of the first and second arc segments, and the curvature of the sixth arc segment is greater than the curvature of the third arc segment.

8. The washable nonwoven fabric as described in claim 7, characterized in that, The minimum spacing between the first and second linear embossing patterns is less than 15 mm.

9. The washable nonwoven fabric as described in claim 8, characterized in that, The first linear embossing is formed by adjacent dot-shaped indentations, and all the dot-shaped indentations constituting the first linear embossing are directional indentations, the directional indentations include a pointing direction, the dot-shaped indentations include an edge line, the edge line includes a large end and a small end, the large end and the small end are both arcs, and the radius of the large end is greater than the radius of the small end, and the length of the dot-shaped indentation is greater than the sum of the radii of the large end and the small end, and at the same time, the ratio of the length to the width of the dot-shaped indentation is less than or equal to 5.

10. The washable nonwoven fabric as described in claim 9, characterized in that, In the first embossing unit, the dot-shaped indentations in adjacent first linear embossing units point in opposite directions.

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