Sheet comprising cellulose regenerated fibers arranged in at least one nonwoven fabric layer

Abstract

A method of producing a sheet and a sheet comprising cellulosic regenerated fibers disposed in at least one nonwoven fabric layer. The sheet comprises at least one non-woven fabric layer of a cellulosic web made of uncut filaments, which is produced in particular by solution jet technology. The sheet has a basis weight between 40 g / m and 70 g / m, preferably between 50 g / m and 60 g / m, a liquid absorption capacity of less than 900%, preferably less than 800%, and more preferably less than 700%, and a lotion release value of greater than 4%, preferably greater than 4.5%, most preferably greater than 5%.

Description

Invention Field

[0001] This disclosure relates to sheets comprising regenerated cellulose fibers arranged in at least one nonwoven fabric layer, methods for producing such materials, and uses of such materials.

[0002] Related technical descriptions Several production techniques for producing nonwoven fabric layers are known in the art. Basically, nonwoven materials can be produced from short fibers or through a direct forming process, wherein the nonwoven fabric layer consists of fibers that have been deposited in a random orientation and collected on a conveyor belt without being cut.

[0003] In the most common technique for producing nonwoven fabric layers from short fibers, a pile fabric is formed by carding the fibers and then bonding them using a hydroentanglement (or spunlace) process. This technique is commonly referred to as “carded-spunlace” and is well known to those skilled in the art.

[0004] Direct molding technology is also referred to by the term "spunbond." The term "spunbond" is a general term encompassing all direct molding technologies such as "meltblown" or "solution-blown." The main characteristics of these technologies are described in the following paragraphs. In this disclosure, the terms "spunbond," "meltblown," and "solution-blown" are used as defined in the following paragraphs. Nevertheless, it is to be understood that the use of these terms in the literature is not consistent and is often confused or used with different meanings or synonyms.

[0005] Synthetic spunbond nonwoven fabrics are produced by extruding plastic melt via a spinneret. In the originally described spunbond process (as disclosed in, for example, GB2114052A or EP3088585A1), filaments are extruded through a nozzle and drawn and stretched by a stretching unit located below. A similar process is the meltblown process (e.g., US5,080,569A, US4,380,570A, or US5,695,377A), in which the extruded filaments, once exiting the spinneret nozzle, are entrained and stretched by hot, rapid process air. In both technologies, the filaments are deposited in random orientation on a deposition surface (e.g., a conveyor belt) to form a nonwoven fabric, which is then fed to subsequent processing steps and ultimately wound into a nonwoven fabric roll.

[0006] Directly molded nonwoven fabrics produced from plastic melt using the methods described above can be manufactured with very low basis weights (e.g., 10 g / m²) and high tensile strengths. However, for applications where absorbency plays a role, such nonwoven fabrics typically have insufficient absorbency. Furthermore, such nonwoven fabrics are either minimally biodegradable or completely non-biodegradable.

[0007] It is also known from US8366988A to produce cellulose nonwoven materials based on spunbond technology.

[0008] To combine the mechanical stability of synthetic spunbond or meltblown nonwoven fabrics with the absorbent properties of wood pulp, a method is described in EP0333211, in which a synthetic meltblown nonwoven product, particularly based on polyester or polyolefin, is combined with a layer of cellulose short fibers or wet-laid wood pulp, for example, in a hydrodynamic manner. Further developments of this method (described, for example, in US5,284,703, US5,587,225, and US2009 / 0233049) have enabled the production of a wider range of products, particularly cheaper, high-volume products for the wiping market. Thus, in this method, by combining an improved air-laid method with meltblowing technology, absorbent nonwoven products can be produced, for example, in which wood pulp fibers are present in a state of uniform distribution on a synthetic polyolefin fiber matrix. Such products are also hampered by their incomplete biodegradability.

[0009] From a contemporary ecological perspective, the combination of synthetic petroleum-based short fibers, such as polyester or polypropylene, and petroleum-based spunbond nonwovens with wood pulp is problematic. Products containing petroleum-based fibers or filaments, manufactured specifically for the mass market, are neither fully biodegradable nor do suitable recycling methods exist. Composite nonwovens made from plastics and wood pulp are sold worldwide and end up in landfills, rivers, or oceans after a single use. This generates microplastics, which are absorbed into the food chain, and their impact on life is not fully predictable. However, even previously, significant amounts of microplastics were generated during the use of such products—as evidenced by evident material shedding and fiber breakage in abrasion tests and subsequent microscopic examinations.

[0010] One spunbonding process that can be used for cellulose materials is solution jetting, as disclosed in, for example, US6358461A and US6306334A. Similar to meltblown processes, this involves extruding cellulose spun material, particularly lyocell spun material, and stretching it by an air stream. However, before deposition into a nonwoven fabric, the filaments are additionally contacted with a coagulant to regenerate the cellulose and produce dimensionally stable filaments. The wet filaments are ultimately deposited as a nonwoven fabric layer with random orientation. In practice, solution jetting has almost nothing in common with classic spunbonding or meltblown processes used for plastic melts, as originally described. Lyocell spun material is a solution with a cellulose content of only 7-14%. Therefore, in solution jetting manufacturing, not only is the cellulose that forms the fibers extruded, but also a much larger amount of solvent. The solvent is then extracted from the nonwoven fabric and recovered in a subsequent washing step.

[0011] The production of nonwoven fabrics with no plastic content and no chemical binders is known from WO2012090130. The wet-laid wood pulp layer is thus bonded to a second nonwoven fabric layer of regenerated cellulose fibers or endless cellulose filaments by means of hydraulic entanglement.

[0012] WO2021170610 discloses a composite nonwoven fabric comprising at least one spunbond cellulose nonwoven fabric produced according to solution jetting technology and at least one bio-based biodegradable short fiber layer.

[0013] JP6267913B2 discloses a solution-jet nonwoven material produced according to the copper-ammonia process.

[0014] When fluids, such as detergents or cleaning solutions, are applied to nonwoven sheets, good liquid absorption properties are required. To provide such good liquid absorption properties, nonwoven fabrics according to existing technology are manufactured with high porosity and pore geometry that supports high liquid absorption. Cellulose fibers typically improve the liquid absorption properties of nonwoven materials. Furthermore, high bulkiness is preferred to improve liquid absorption. Only with sufficiently high liquid absorption can a adequate amount of liquid be released during use. Nevertheless, a large amount of fluid still cannot be released but remains within the nonwoven fabric structure and is disposed of as waste along with the product after use.

[0015] One object of this disclosure is to provide teachings on how to reduce the amount of waste fluid retained in nonwoven materials after use. Another object is to provide sheets that can hold lower amounts of fluid while still providing the same performance as high-load nonwoven fabrics known in the art.

[0016] Overview This disclosure relates to a sheet comprising regenerated cellulose fibers disposed in at least one nonwoven fabric layer, wherein the sheet comprises at least one nonwoven fabric layer of a cellulose web made from uncut filaments, particularly produced by spunbonding, preferably by solution jetting, wherein the sheet has a basis weight between 40 g / m² and 70 g / m², preferably between 50 g / m² and 60 g / m², a liquid absorption capacity of less than 900%, preferably less than 800%, more preferably less than 700%, and a detergent release value of greater than 4%, preferably greater than 4.5%, most preferably greater than 5%.

[0017] As used herein, the term "uncut filament" refers to a filament that has been produced or fed into a nonwoven fabric layer in an uninterrupted manner (e.g., by continuous extrusion via a spinneret) and has not undergone any intentional cutting process before the formation of the nonwoven fabric layer.

[0018] Cellulose nonwoven fabric layers produced by spunbonding, preferably by solution jetting technology, enable very fine and targeted adjustment of production parameters to produce nonwoven fabric layers according to the preferred embodiments disclosed herein.

[0019] As used in this article, the term "spunbond" refers to any method of directly forming a nonwoven fabric layer from uncut filaments.

[0020] As used herein, the term "solution jetting" refers to a method of forming a nonwoven fabric layer from a cellulose spinning solution, particularly a lyocell spinning solution. The spinning solution is thus extruded in an uncut manner to form a filament, which is then stretched by an air stream, at least partially coagulated by a coagulant, and subsequently deposited in a random orientation onto a deposition surface to form a nonwoven fabric layer.

[0021] The inventors have unexpectedly discovered that, based on the teachings disclosed herein, it is possible to reduce the liquid absorption capacity of nonwoven materials while simultaneously increasing the detergent rewetting value of the same nonwoven material. This overcomes the common assumption that, in order to increase detergent release, the liquid absorption capacity must also be increased so that the nonwoven material can hold more liquid. The present invention enables an overall reduction in the amount of detergent required for desired detergent release. Since detergent is a major cost driver for many fluid-carrying nonwoven products, significant cost reductions can be achieved according to this disclosure.

[0022] As illustrated in the examples, currently available nonwoven sheets for wet wipes, etc., are not within the specified parameter range. It is generally assumed that only cellulose nonwoven products with higher basis weight and / or higher liquid absorption capacity can achieve high release values. Lowering any one (or both) of these parameters would naturally also lower the detergent release value. Through the teachings disclosed herein, those skilled in the art can increase the detergent release value to the specified range while maintaining (or even lowering) the basis weight and / or liquid absorption capacity. The method features that enable simultaneous optimization of these conflicting parameters depend on the specific manufacturing method and are fully described herein.

[0023] As used herein, the term "nonwoven fabric layer" refers to a flat nonwoven structure produced according to any method known in the art, and in particular any method described or mentioned in this disclosure.

[0024] As used herein, the term "sheet" refers to a product comprising one or more layers of nonwoven fabric (or consisting of one or more layers of nonwoven fabric).

[0025] As used herein, the term “basic weight” (BW) refers to the value that can be measured according to NSWP 130.1.R0(15) [EN].

[0026] As used herein, the term “liquid absorption capacity” (LAC) refers to a value that can be measured according to NWSP 010.1.R0 (15) [EN].

[0027] Detergent release value can be measured using a roller test according to the following scheme: Cut 10 samples, each measuring 20 cm x 20 cm, from the sheet.

[0028] All samples were conditioned for 24 hours at 23℃ (+ / -2℃) and 50% (+ / -5%) relative humidity.

[0029] Each sample was weighed to determine the weight of the unloaded sample.

[0030] Three times the weight of softened water is carefully loaded onto the sample by spraying. In this disclosure, the term "three times" means that the weight of the loaded fluid (i.e., softened water) corresponds to three times the weight of the unloaded sample.

[0031] The five samples were then sealed in a bag and stored at ambient temperature for two days to allow the fibers to balance and swell.

[0032] The samples were disassembled and weighed individually to determine the weight of the loaded sample (WLS).

[0033] The liquid is then extruded by passing each sample horizontally through a roller press set at a roller speed of 3 m / min and a pressure of 0.5 bar. The sample is passed through the roller press along the machine direction of the sample material.

[0034] Each sample was weighed again after extrusion to determine the weight of the extruded sample (WSS).

[0035] The weight of the extruded liquid (WL) is determined by the formula WL=WLS-WSS as the weight difference of the sample before and after extrusion.

[0036] Detergent release value (LRV) is determined by the formula LRV=(WL / WLS)*100 [%] as the percentage of the weight of the extruded liquid relative to the weight of the loaded sample.

[0037] For the roll pressing test according to this scheme, a roll press with a roll diameter of 110 mm and a roll length of 500 mm can be used, such as a roll press of the Foulard HVF 500 41796 type, but the same measurement results can also be achieved by using an equivalent roll press.

[0038] It must be pointed out that the rolling test disclosed herein reflects very well the ability of the sheet to release a certain amount of fluid during use. To the applicant's knowledge, as of the priority date of this document, there is no standard test for this property of the sheet; therefore, the test protocol described herein was created. Because this test protocol is simple and easy to perform, it will be apparent from this application that those skilled in the art will not encounter difficulties in conducting the proposed test, and thereby will be able to establish the precise meaning of the parameter and make a meaningful comparison with the prior art.

[0039] Spunbond, especially solution jetting technology, allows for highly precise and reproducible adjustment of properties, particularly filament thickness, and the structure and distribution of pores can be easily tuned over a wide range. Furthermore, solution jetting technology offers the possibility of adjusting the amount of fusion allowed between different filaments when they are deposited on a deposition surface. Fusion occurs if a nonwoven fabric layer is formed while the filaments are still in a partially condensed state. In practice, the amount of fusion is primarily adjusted by regulating the amount of condensing fluid applied to the newly spun filaments between the spinneret and the pile-forming unit (i.e., the moving support on which the filaments are laid). Additionally, the diameter and / or diameter distribution of the filaments can be adjusted by the spinneret size, spinneret orifice diameter, spinning solution flow rate, stretching air flow rate, and condensation spray intensity.

[0040] As shown in the examples, nonwoven sheets can be directly produced using a solution jetting process according to the parameters disclosed herein. The term "direct production" means that no additional processing steps, such as applying adhesives or adding other materials, such as wood pulp, are required.

[0041] It is believed that, for technically and economically feasible sheets, the liquid absorption capacity should be at least 300% (for materials with a basis weight of approximately 50 g / m²). The detergent release value should be as high as possible. A detergent release value of up to 12% or even higher is believed to be achievable.

[0042] According to a preferred embodiment, the sheet may have a thickness between 0.35 mm and 0.6 mm, preferably between 0.4 and 0.5 mm.

[0043] The thickness within this range is generally lower than that of most wipes currently available on the market. By reducing thickness, the liquid absorption capacity can be reduced. By simultaneously reducing pore volume, detergent release can remain high or even increase. For example, pore volume can be reduced by producing a relatively high bulk density.

[0044] The term “thickness” (TH) refers to the value measured according to NWSP 120.6.R0 (15) [EN], method A.

[0045] According to another preferred embodiment, the sheet may have a bulk density of at least 100 kg / m³, preferably at least 125 kg / m³, which is defined as the basis weight divided by the thickness.

[0046] As used in this article, the term “bulk density” (BD) refers to the basis weight divided by the thickness.

[0047] It has been found that detergent release values ​​can be adjusted by changing the bulk density. Higher bulk density generally increases detergent release values. Unbound from this theory, it is believed that higher bulk density leads to a reduction in the amount of voids and pores (where fluids can bind) between fibers and / or filaments. Therefore, fluid absorption occurs primarily within the cellulose fibers, which surprisingly increases detergent release values.

[0048] In another preferred embodiment, the sheet may comprise biodegradable short fibers, preferably wood pulp fibers, integrated into the at least one nonwoven fabric layer.

[0049] Biodegradable short fibers integrated into nonwoven fabric layers can be applied in a way that fills the voids in the structure and thus increases the packing density. This feature can therefore be used to manufacture nonwoven sheets according to parameters specified herein.

[0050] Bio-based, biodegradable short fibers can be applied in a way that fills the voids in nonwoven sheets, thus further reducing the amount of voids and pores in the material and promoting a very dense structure. This further reduces liquid absorption capacity and, surprisingly, has been found to help improve detergent release values.

[0051] Bio-based biodegradable short fibers, for example, cellulose pulp, can be used, which can be applied to a nonwoven matrix via wet web forming or air-laid web forming techniques.

[0052] The techniques for integrating short fibers into nonwoven materials are known in the art, for example, from WO2021170610A1 filed by the same applicant. Where legally permissible, the disclosure of WO2021170610A1 is hereby incorporated herein by reference in its entirety.

[0053] According to another aspect, this disclosure relates to the use of sheets as disclosed herein for the production of fluid-laden wipes.

[0054] Compared to existing technologies, less fluid is required to produce fluid-loaded wipes. Nevertheless, users experience the same or even better cleaning properties. To produce wipes, a base material consisting of sheets as disclosed herein can be cut, packaged, and loaded with fluid (in any technically reasonable order).

[0055] According to another aspect, this disclosure relates to a wiping cloth comprising a sheet as disclosed herein.

[0056] Such wipes can hold a low volume of fluid, which reduces costs and has a positive environmental impact.

[0057] Examples of wiping wipes include, but are not limited to, cleaning wipes, cosmetic care wipes, exfoliating wipes, polishing wipes, body care wipes, freshening wipes, and deodorizing wipes.

[0058] According to a preferred embodiment, the wiping cloth may contain fluid.

[0059] When fluid is loaded onto the wiping cloth during the production process, the lower fluid volume results in reduced transportation costs due to the lighter weight.

[0060] According to another embodiment, the wiping cloth may carry a fluid selected from the following list: water-based fluid, oil-based fluid, disinfectant fluid, fluid containing cleaning agents, fluid containing skin care agents, and fluid containing makeup removers.

[0061] Therefore, cleaning wipes are suitable for a wide range of possible applications.

[0062] According to another aspect, this disclosure relates to a method of producing a sheet comprising regenerated cellulose fibers arranged in at least one nonwoven fabric layer, wherein the sheet comprises at least one nonwoven fabric layer of a cellulose web made from uncut filaments, produced particularly by solution jetting technology, wherein production parameters are selected to produce a sheet having a basis weight between 40 g / m² and 70 g / m², preferably between 50 g / m² and 60 g / m², less than 900%, preferably less than 800%, more preferably less than 700% of a liquid absorption capacity, and greater than 4%, preferably greater than 4.5%, most preferably greater than 5% of a detergent release value.

[0063] Based on the teachings disclosed herein, those skilled in the art can select and adjust production parameters to regulate the properties of the sheet within a specified range that allows the liquid absorption capacity to be within a given range. Similarly, production parameters can be selected to regulate the properties of the sheet within a specified range that allows the detergent release value to be within a given range.

[0064] Because the interactions of different production parameters during the production of nonwoven sheets are complex, the optimal values ​​for material properties (such as bulk density and relative pore volume) can only be specified under the specific circumstances of a particular production process and its parameters. Nevertheless, with an understanding of the teachings disclosed herein, those skilled in the art can select and find the production parameters required to produce sheets within the claimed scope and achieve the effects disclosed herein.

[0065] As used herein, the term "porosity" is defined as the fractional empty space contained within a material. Furthermore, the three-dimensional pore geometry and fiber and / or filament diameters must be considered and can be adjusted according to the teachings disclosed herein to produce sheets with specified parameters.

[0066] In the case of solution jet technology (i.e., direct manufacturing from a lyocell spinning solution in the form of substantially uncut regenerated cellulose fibers), the settings for producing sheets within the optimal values ​​disclosed herein can be found, for example, by the following method: To modify the properties of nonwoven materials, the following general rules apply.

[0067] - If the belt speed remains constant, increasing the throughput of the spinning solution at the spinneret under constant pressure of the stretching air will increase the thickness of the filament and the thickness of the fabric, as well as the basis weight of the nonwoven fabric layer thus produced.

[0068] Increasing the stretching airflow at the spinneret results in nonwoven fabric layers containing finer fibers arranged in a more entangled manner. This typically increases the bulk density, leading to a thinner layer with a reduced liquid absorption capacity.

[0069] - Increasing the speed at which the support on which the nonwoven fabric layer is formed will reduce the thickness and weight of the nonwoven fabric layer.

[0070] - To reduce the liquid absorption capacity, the amount of voids and pores can be reduced. The reduced voids then absorb less fluid, which is then primarily incorporated into the cellulose matrix of the filament.

[0071] Reducing the amount of condensation spray results in greater filament bonding within the nonwoven fabric layer. This layer will be produced thinner and with a higher degree of filament bonding (i.e., the filaments are stuck together). This makes the nonwoven fabric layer denser and reduces porosity. This also leads to higher packing density and reduced thickness.

[0072] Higher condensation spray intensity results in reduced filament fusion and increased bulk. By increasing the thickness of the filaments and increasing the amount of condensation (which reduces fusion), thicker and bulkier nonwoven fabric layers can be produced.

[0073] As a starting point, settings can be adjusted to produce nonwoven materials with the desired basis weight, where the values ​​of condensation spray intensity and tensile air strength can be selected within the intermediate range of possible settings. Other parameters can be selected according to other requirements of the specific nonwoven material to be produced. It must be noted that, under normal circumstances, nonwoven materials thus produced do not possess the specific properties specified herein.

[0074] To find suitable settings for producing nonwoven materials according to this disclosure, production parameters are systematically adjusted to reduce voids. Void reduction can be achieved, in particular, by increasing the stretching airflow and / or decreasing the condensation spray intensity.

[0075] According to a preferred embodiment, the method includes one or more of the following features: - The sheet thickness, measured according to NWSP 120.6.R0 (15) [EN], method A, shall be adjusted to a value between 0.35 mm and 0.6 mm, preferably between 0.4 mm and 0.5 mm. - Adjust the bulk density of the sheet (defined as basis weight divided by thickness) to at least 100 kg / m³, preferably at least 125 kg / m³.

[0076] The thickness and packing density within these ranges enable the production of resource-saving end products.

[0077] Those skilled in the art who understand the teachings disclosed herein will be able to adjust production parameters to achieve and optimize these values ​​within these preferred ranges.

[0078] According to another preferred embodiment, bio-based biodegradable short fibers, preferably wood pulp fibers, can be integrated into the at least one nonwoven fabric layer.

[0079] Several production techniques are known for incorporating short fibers, such as wood pulp (in the form of a liquid suspension containing wood pulp or as dry fluff pulp), into the matrix of nonwoven fabric layers. Non-exhaustive examples include carding-wet web forming-wood pulping technology, carding-airflow web forming-carding technology, or the technology disclosed in WO2021170610A1.

[0080] After the wood pulp is applied to the nonwoven material, preferably by wet web forming or air-laid web forming technology, the composite material can be pressed and compacted in a roller press and / or bonded by hydroentangling.

[0081] The integration of short fibers can reduce voids and pores in the material. Furthermore, wood pulp has a particularly positive impact on the product's softness and detergent release value.

[0082] According to yet another preferred embodiment, the nonwoven fabric layer of the at least one cellulose web can be subjected to the pressure of a roller press in a never-dried state to adjust the thickness of the sheet.

[0083] By adjusting the thickness in a never-dried state, the bulk density can be increased, thereby increasing the detergent release value. Rolling can be applied directly to a single layer of nonwoven fabric containing a cellulose web, or after short fiber integration. Furthermore, the rolling step can be applied before or after the hydroentangling step (if such a step is provided).

[0084] As used herein, the term “never dried” refers to a nonwoven fabric layer that has been deposited on the deposition surface, where the nonwoven fabric layer is still wet with a substantially fully swollen fibrous structure and has not yet experienced a heated airflow for drying.

[0085] According to another aspect, this disclosure relates to the use of sheets produced as disclosed herein and / or by any method disclosed herein for the production of consumer and / or industrial products, wherein the consumer and / or industrial products are preferably selected from wet wipes, cosmetic sheet masks, dry wipes designed to be moistened with liquid, liquid application systems, wound care products, etc. Example

[0086] Prepare the following nonwoven sheet samples: Comparative Material 1 As the first comparative sample, a conventional nonwoven material was prepared using a carding and hydroentangling technique. This material was prepared using 1.7 dtex Lyocell fibers with a length of 38 mm. The fibers were carded to form a pile fabric with the desired basis weight (see Table 1 below), and then hydroentangled using five spunlacejet bars at a linear velocity of 100 m / min under an upward pressure setting.

[0087] Comparative Material 2 As a second comparative sample, a conventional nonwoven material was prepared using a carded hydroentangling technique. This material was prepared with the same setup as comparative material 1, but using 1.7 dtex viscose fibers with a length of 38 mm.

[0088] Innovative Materials 1 A nonwoven fabric layer of cellulose web, produced using uncut lyocell filaments, is manufactured according to the teachings of this disclosure using solution jetting technology. Production parameters are set to achieve high bulk density (by reducing the intensity of the coagulation spray to increase filament fusion and increasing the stretch airflow) and low thickness to reduce liquid absorption capacity. Linear speed and throughput are set to achieve a carrier material with a nominal basis weight of 20 g / m². Wet-laid wood pulp is then loaded onto this undried material to achieve a total nominal basis weight of approximately 60 gsm, and hydroentangling is performed to bond the wet-laid wood pulp to the carrier material. To flatten the structure and further increase the bulk density, the material is guided through pressure rollers before drying. The composite is then dried and then collapsed into a very flat, dried carrier wood pulp composite.

[0089] Innovative Materials 2 A nonwoven fabric layer of cellulose web, produced using uncut lyocell filaments, is manufactured according to the teachings of this disclosure using solution jetting technology. This material is not produced using wet-laid wood pulp, unlike Innovative Material 1. Linear speed and throughput are set to achieve a nonwoven material with a nominal basis weight of 60 g / m². To achieve a flat structure with high bulk density, a combination of relatively high filament draw (fine filaments) and relatively high cohesion (low condensation flow rate) is used. The fabric is then hydroentangled under low pressure settings to maintain a low material thickness. The material is subsequently dried (which causes further thickness collapse) and wound.

[0090] Table 1 shows the main properties of the sample and the control sample, namely BW - Basis weight measured according to NSWP 130.1.R0(15) [EN]. TH - Thickness measured according to NWSP 120.6.R0 (15) [EN], method A LAC - Liquid absorption capacity measured according to NWSP 010.1.R0 (15) [EN]. BD - Bulk density (basic weight divided by thickness).

[0091] Table 1 - Sample Properties sample BW [g / m²] TH [mm] LAC [%] BD [kg / m³] Comparative Material 1 55 0.59 1016 93 Comparative Material 2 57 0.46 967 123 Innovative Materials 1 57 0.43 651 133 Innovative Materials 2 58 0.41 662 140

[0092] As can be seen from Table 1, the liquid absorption capacity of the innovative material is much lower than that of the comparative material. Furthermore, compared to the comparative material, the innovative material is thinner and has a higher packing density.

[0093] For all samples and control samples, the liquid absorption capacity was determined using the protocol disclosed herein. The following measurements are shown in Table 2: WLS – Weight of the loaded sample WSS - Weight of the extruded sample WL - Weight of the extruded liquid LRV - Detergent Release Value All measurements were derived from 10 independently measured samples for each material. For all cases, the measurement results (line x) and the standard deviation of the 10 measurements (line s) are given.

[0094] Table 2 - Measurement of sample detergent release values

[0095] Table 2 shows that, despite the reduced liquid absorption capacity, both innovative materials exhibited significantly higher detergent release values ​​than the comparative materials.

[0096] The inventors believe that a material with properties similar to Innovative Material 1 can be produced by combining 40 gsm wood pulp paper with 20 gsm undried carrier material in-line to manufacture a 60 gsm wood pulp composite material, and then hydroentangling and drying it.

Claims

1. A sheet comprising regenerated cellulose fibers arranged in at least one nonwoven fabric layer, wherein the sheet comprises at least one nonwoven fabric layer of a cellulose web made from uncut filaments, particularly produced by spunbonding, preferably by solution jetting, wherein the sheet has a basis weight of less than 900%, preferably less than 800%, more preferably less than 700%, between 40 g / m² and 70 g / m², preferably between 50 g / m² and 60 g / m², a liquid absorption capacity of greater than 4%, preferably greater than 4.5%, most preferably greater than 5%, and a detergent release value of greater than 4%, preferably greater than 4.5%, most preferably greater than 5%.

2. The sheet according to claim 1, wherein the sheet has a thickness between 0.35 mm and 0.6 mm, preferably between 0.4 mm and 0.5 mm.

3. The sheet material according to claim 1 or 2, wherein the sheet has a bulk density of at least 100 kg / m³, preferably at least 125 kg / m³, which is defined as the basis weight divided by the thickness.

4. The sheet according to any one of claims 1 to 3, wherein the sheet comprises biodegradable short fibers, preferably wood pulp fibers, integrated into the at least one nonwoven fabric layer.

5. Use of the sheet according to any one of claims 1 to 4 for the production of fluid-containing wipes.

6. A wiping cloth comprising a sheet according to any one of claims 1 to 4.

7. The wiping cloth according to claim 6, wherein the wiping cloth carries a fluid.

8. The wiping cloth of claim 7, wherein the wiping cloth carries a fluid selected from the list of: water-based fluids, oil-based fluids, disinfectant fluids, fluids containing cleansing agents, fluids containing skin care agents, and fluids containing makeup removers.

9. A method of producing a sheet comprising regenerated cellulose fibers arranged in at least one nonwoven fabric layer, wherein the sheet comprises at least one nonwoven fabric layer of a cellulose web made from uncut filaments, particularly produced by spunbonding, preferably by solution jetting, wherein production parameters are selected to produce a sheet having a basis weight between 40 g / m² and 70 g / m², preferably between 50 g / m² and 60 g / m², less than 900%, preferably less than 800%, more preferably less than 700%, and a detergent release value greater than 4%, preferably greater than 4.5%, most preferably greater than 5%.

10. The method of claim 9, wherein the method comprises one or more of the following features: - The thickness of the sheet, measured according to method A of NWSP 120.6.R0 (15) [EN], shall be adjusted to a value between 0.35 mm and 0.6 mm, preferably between 0.4 mm and 0.5 mm. - Adjust the bulk density of the sheet—defined as the basis weight divided by the thickness—to a value of at least 100 kg / m³, preferably at least 125 kg / m³.

11. The method according to claim 9 or 10, wherein bio-based biodegradable short fibers, preferably wood pulp fibers, are integrated into the at least one nonwoven fabric layer.

12. The method according to any one of claims 9 to 11, wherein the nonwoven fabric layer of the at least one cellulose web is subjected to pressure from a roller press in a never-dried state to adjust the thickness of the sheet.

13. The sheet according to any one of claims 1 to 4 and / or the sheet produced by the method according to any one of claims 9 to 12 for use in the production of consumer and / or industrial products, wherein the consumer and / or industrial products are preferably selected from wet wipes, cosmetic sheet masks, dry wipes designed to be moistened with liquid, liquid application systems, wound care products, etc.

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