Coreless roll of tissue paper product and method of manufacturing a coreless roll

Abstract

This disclosure relates to a coreless roll of a tissue paper product, such as a household towel, made from a continuous web of tissue paper product spirally wound with a first end and a second end. The web of tissue paper product is wound to define an axially extending inner hole positioned relative to the center of the coreless roll, such that the first end is located outside the coreless roll and the second end is located at the inner hole. The tissue paper product comprises two layers, namely a first layer and a second layer, which are laminated together, optionally using an adhesive such as a laminating adhesive, and / or a mechanical bonding such as edge embossing, to form the tissue paper product. The basis weight of the tissue paper product is between 35 and 55 g / m². 2 Within a certain range. The tissue paper product has a geometric mean tensile strength of at least 200 N / m. The first and second layers are made of conventional wet-pressed (CWP) paper. The first and second layers have been embossed for nesting. The outer diameter of the coreless roll is in the range of 95 to 150 mm, the inner diameter is in the range of 20 to 50 mm, and the density of the coreless roll is in the range of 70 to 90 kg / m³. 3 Within the range. The caliper measurement of the roll is within the range of 40% to 70%. This is determined by the standard caliper measurement c for tissue paper products as defined by standard ISO-12625-3:2014. s Theoretical caliper measurement value c for cotton paper products t The difference between them divided by the theoretical caliper measurement c t To obtain the caliper measurement ratio (c) s -c t ) / c t Theoretical caliper measurement value c t Defined as the ratio between the basis weight of a tissue paper product and the density of the roll.

Description

Technical Field

[0001] This disclosure relates to coreless rolls of cotton paper products, such as household towels, made from a continuous web of helically wound cotton paper products. This disclosure also relates to cotton paper products. Furthermore, this disclosure relates to methods for manufacturing coreless rolls of cotton paper products, such as household towels, and methods for manufacturing cotton paper products. Background Technology

[0002] In the following text, "cotton paper products" refers to absorbent paper based on cellulose fillers. The latter is also known in this technical field as cotton paper-based sheets.

[0003] The fibers contained in tissue paper products are primarily cellulose fibers, such as pulp fibers from chemical pulp (e.g., kraft paper or sulfite), mechanical pulp (e.g., ground wood), thermomechanical pulp, chemimechanical pulp, and / or chemithermomechanical pulp (CTMP). Pulps from deciduous (hardwood) and coniferous (softwood) wood can be used. Fibers may also be derived from non-wood plants such as cereals, bamboo, jute, and sisal. Fibers, or a portion thereof, may be recycled fibers, which may belong to any or all of the categories mentioned above. Fibers may be treated with additives, such as fillers, softeners, such as, but not limited to, quaternary ammonium compounds and binders, conventional dry strength agents, temporary wet strength agents, or wet strength agents, to facilitate priming or adjust their properties. Tissue paper products may also contain other types of fibers, such as regenerated cellulose fibers or synthetic fibers, to enhance the tissue paper product's strength, absorbency, smoothness, or softness.

[0004] In this article, whenever the “softness” of a tissue paper product is mentioned, it refers to the softness characteristic determined by the evaluation of a review committee. In this case, a review committee of ten members was used. The list of review committee members was used to rank the products according to softness. The softness review committee value was used as a comparison value for comparison between the tested samples. The softer the product / tissue paper product, the higher the rating. In this case, the softness grades were set from 0 to 2.5 (2.5 being the highest value). Each sample consisted of one product, namely a tissue paper product. Optionally, each sample was a single layer. Each sample was first conditioned in a controlled area at 23°C and 50% relative humidity for at least two hours. Then, it was evaluated by the review committee members.

[0005] Tissue paper products can be used for personal and household purposes as well as commercial and industrial applications. They can be suitable for absorbing fluids, removing dust, and for other cleaning purposes. The process of making tissue paper from pulp essentially involves a forming step, which includes a headbox and forming line section, and a drying section, either by air drying or conventional drying on Yankee rollers. The manufacturing process may also include creping, and finally, typically monitoring and winding, steps.

[0006] Several layers can be combined together by chemical (e.g., by adhesive bonding) or mechanical (e.g., by knurling or so-called edge embossing) operations, or a combination of both.

[0007] Furthermore, the processing of finished tissue paper products may include, for example, longitudinal cutting and transverse cutting. Additionally, individual tissue paper products may be positioned and stacked together to form a pile, which can then be individually packaged. This processing step may also include the application of substances such as odorants, emulsions, softeners, or other chemical additives.

[0008] When several layers are combined together using an adhesive bond, an adhesive film is deposited on some or all of the surfaces of at least one layer, and then the adhesive-treated surface comes into contact with the surface of at least one other layer.

[0009] When mechanical bonding is used to combine several layers together, these layers can be combined by knurling, compression, edge embossing, joint embossing, and / or ultrasonic bonding. Additionally, or alternatively, at least some bonding can be performed using water instead of other adhesives.

[0010] Mechanical bonding and adhesive bonding can also be combined to create several layers.

[0011] The processing steps from base cotton paper to finished cotton paper products occur in processing machines (conversion machines), which include operations such as unfolding base cotton paper, calendering cotton paper, laminating, printing or embossing together to form multi-layered products.

[0012] Embossing can be used to change the shape of a layer from flat to shaped, so that there are areas that are raised and / or recessed from the rest of the surface. Therefore, it constitutes a deformation of the previously flat sheet and results in a layer with a specific embossing. The thickness of an embossed layer or multiple layers increases compared to its initial thickness.

[0013] The embossing process takes place between an embossing roll and a counterroller. The embossing roll may have protrusions or depressions on its circumferential surface, resulting in embossed protrusions / depressions in the paper web. The counterroller can be softer than the corresponding embossing roll and can be made of rubber (e.g., natural rubber), plastic, paper, or steel. If the counterroller is made of a softer material such as rubber, a contact area / gap can be formed between the embossing roll (e.g., a steel roll) and the counterroller through deformation of the softer roll.

[0014] Embossing allows patterns to be applied to tissue paper for decorative and / or functional purposes. Functional purposes can include improving the performance of the tissue paper product; embossing can improve the product's thickness, absorbency, volume, softness, etc. Functional purposes can also include providing adhesion to another layer in a multi-layer product.

[0015] Another type of embossing is referred to here as "pre-embossing". Pre-embossing can preferably be applied to the web or layer before it is bonded to the other layers of the multilayer tissue paper product.

[0016] This pre-embossed pattern is manufactured for functional purposes such as, as described above, to increase the thickness, absorbency, volume, and / or softness of the layer.

[0017] "Micro embossing" is used here to refer to embossed patterns with a dense structure. Typically, micro embossing can comprise dots ranging from 25 to 120 dots per square centimeter. Micro embossing can advantageously be pre-embossed. Micro embossed dots can have different, relatively simple surface shapes, such as circles, ovals, squares, rectangles, or rhombuses.

[0018] It is well known that producing rolls of tissue paper products (such as household towels) without a core (e.g., without an additional cardboard core) is attractive because it reduces waste (since the core of a used roll is a waste product). However, coreless rolls are not always as satisfying to customers as cored rolls, for example, due to reduced stability compared to cored rolls.

[0019] Therefore, there is a need for improved coreless reels that enhance customer satisfaction while allowing for reduced waste (particularly by avoiding the need to provide cores that typically end up as waste). Specifically, such coreless reels should address at least one of the aforementioned drawbacks. Furthermore, there is a need for an improved method of manufacturing coreless reels that addresses at least one of the aforementioned drawbacks.

[0020] Furthermore, while the multilayer tissue paper products and their manufacturing methods proposed in the past may be very useful in many applications, improvements are still needed. In particular, improvements are desired in terms of the thickness, strength, softness, volume, and / or absorbency of multilayer tissue paper products. Summary of the Invention

[0021] One aspect of the aforementioned objective is achieved by a coreless roll of a tissue paper product, such as a household towel, which is made by spirally winding a continuous web of tissue paper product having a first end and a second end. The web of tissue paper product is wound to define an axially extending inner hole that is centrally positioned relative to the coreless roll, such that the first end is located outside the coreless roll and the second end is located at the inner hole.

[0022] As described in this article, the diameter of the inner hole can be understood as the “average diameter” obtained by dividing the circumference of the inner hole by π (π can, of course, be approximated, for example, 3.14). The actual distance between the opposing surfaces of the inner hole can vary as the roll moves along the circumference, since the inner hole does not need to have a circular cross-sectional shape, but it will usually vary slightly (e.g., depending on the orientation of the roll during transport, etc.).

[0023] This tissue paper product comprises two layers, namely, a first layer and a second layer. In other words, the total number of layers in the tissue paper product is two. To put it another way, the tissue paper product consists of two layers. However, this latter statement does not mean that the tissue paper product cannot contain other components (besides the layers), such as adhesives, additives, etc. It simply means that the number of layers is two. At least one of the two layers can be an embossed layer. However, both layers can be embossed layers.

[0024] The first and second layers have been laminated, optionally using adhesives such as laminating glue and / or mechanical bonding such as edge embossing, to form the tissue paper product.

[0025] The basis weight of the tissue paper products is between 35 and 55 g / m². 2 Within the range.

[0026] This tissue paper product has a geometric mean tensile strength of at least 200 N / m. The first and second layers are made of conventional wet-pressed (CWP) paper.

[0027] According to the "conventional wet paper" (CWP) process, the fabrication layers from the paper fibers can rely on the manufacture of either "dry crepe paper" or "wet crepe paper," and must be distinguished from "structured paper processes," such as air-through drying (TAD) manufacturing methods, the manufacture of crepe-free air-through drying (UCTAD) paper, or alternative manufacturing methods, such as Voith's Advanced Paper Molding System (ATMOS), Georgia Pacific's energy-efficient Advanced Drying eTAD technology, or Metso Paper's Structured Paper Technology (SST). Furthermore, hybrid processes, such as NTT (Metso Paper's New Textured Paper), can be used as an alternative to traditional processes.

[0028] The first and second layers are embossed to be nested.

[0029] Nested structures are the result of processes in which sheets are individually embossed with precisely registered patterns. For example, two layers (or, for other products, more than two layers) of macro-embossed areas do not overlap (or overlap only to a small extent, i.e., 1% or less of the total macro-embossed area, optionally 0.5% or less). This limitation on overlap promotes high caliper values, high caliper ratios, and high compressive strength of the sheet, thereby promoting high compressive strength and quality in coreless rolls.

[0030] When each layer is also microembossed (either in a separate stage or in the same stage of the conversion process), the microembossing may not be registered and may not play any role in the lamination process (where all layers are bonded together).

[0031] The outer diameter of the coreless winding ranges from 95 to 150 mm, and the inner diameter ranges from 20 to 50 mm.

[0032] The density of coreless rolls is between 70 and 90 kg / m. 3 Within the range. Roll density (in this document) is defined as the ratio between the weight of the roll and the volume of the tissue paper product. The expression "volume of the tissue paper product" is used to refer to the difference between the external volume of the coreless roll and the volume of the inner cylinder defined by the inner hole.

[0033] The caliper measurement ratio of the roll is in the range of 40% to 70%. Caliper measurement ratio (c) s -c t ) / c t It is achieved by measuring the standard caliper value c of tissue paper products as defined by standard ISO-12625-3:2014. s Theoretical caliper measurement value c for cotton paper products t The difference between them divided by the theoretical caliper measurement c t The theoretical caliper measurement value c was obtained from this. t Defined as the ratio between the basis weight and roll density of a tissue paper product.

[0034] If the caliper measurement ratio is below 40%, the radial compressive strength of the coreless roll may be unsatisfactory. If the caliper measurement ratio is above 70%, the embossing load required to manufacture the coreless roll may negatively affect the tensile strength of the tissue paper product.

[0035] In this article, whenever "caliper measurement" or "thickness" is mentioned, it refers to the thickness obtained using a Frank thickness gauge (model 16502) or similar equipment according to ISO 12625-3:2014. The cotton paper sheet to be measured is cut into pieces with a minimum diameter of 80 mm in any direction, and these pieces are conditioned at 23°C and 50% RH (relative humidity) for at least 2 hours. During the measurement, the sample piece is placed between the fixed base plate and the pressure foot. The pressure foot is then lowered at a speed of 2.0 mm / s. The thickness value of the sheet is then read after the pressure value stabilizes. The inner diameter of the pressure foot in Essity is 35.7 mm. The minimum lower plate size is 20% larger. The pressure applied during the measurement is 2.0 kPa.

[0036] The caliper measurement for tissue paper products can be at least 0.7mm.

[0037] At least one of the two layers has been embossed using heated embossing rollers.

[0038] The first layer can have been embossed with heated embossing rollers. Compared to a similarly manufactured reference product without heat embossing (i.e., embossing without heated embossing rollers), this can promote higher tensile strength and / or greater caliper values ​​in the tissue paper product without (or with little to no) reducing the softness of the tissue paper product.

[0039] The second layer can have been embossed with heated embossing rollers. Compared to a similarly manufactured reference product without heat embossing (i.e., embossing without heated embossing rollers), this can promote higher tensile strength and / or greater caliper values ​​in the tissue paper product without (or with little to no) reducing the softness of the tissue paper product.

[0040] As described herein, any heated or heatable embossing roller can be heated from the inside or outside by a heating device. The heating device may include a heat-carrying fluid and / or rely on induction and / or infrared heating. However, the heating device may include any type of heating system, and there are no particular limitations in this regard.

[0041] As described herein, any heated or heatable embossing roller can be heated to surface temperatures ranging from 80°C to 240°C, optionally from 100°C to 220°C, or 110°C to 190°C, or 120°C to 180°C, or 130°C to 165°C. These temperature ranges can be narrowed to an even greater extent, facilitating the manufacture of tissue paper products with good shape memory and / or large thickness, high mechanical direction (MD) and / or cross direction (CD) tensile strength, and good absorbency.

[0042] The temperature of any heated embossing roller mentioned in this article specifically refers to the surface temperature of the embossing roller. These can be measured, for example, using an infrared thermometer. Furthermore, the temperature value refers to the temperature under steady-state conditions of the manufacturing equipment, i.e., not during operation and when the layers are in contact with the embossing roller. In particular, the surface temperature of a heated embossing roller may decrease during manufacturing due to various factors such as heat conduction to the layers in contact with the roller. For example, a surface temperature of 170°C can be measured under steady-state conditions (when the embossing roller is not in contact with the layers), and this temperature can be reduced to a range of 100°C to 130°C during manufacturing, and so on.

[0043] Coreless rolls of the aforementioned two-layered tissue paper products can have a high caliper value ratio combined with high geometric mean tensile strength. Nested structures can facilitate this and allow for avoiding the need for forced hybrid structures (requiring at least one expensive structuring layer) or heated embossing or specific embossing designs to manufacture good coreless rolls with consumer-acceptable performance.

[0044] Due to its high caliper strength, the aforementioned coreless rolls are robust in terms of handling and storage performance.

[0045] The aforementioned coreless rolls of tissue paper products made of two layers can have exceptionally high radial compressive strength. Specifically, the radial compressive strength of such rolls can be 20N or greater, or even 25N or greater, or even 30N or greater. These are robust and meet requirements, for example, for use in household towels. Therefore, they can achieve customer satisfaction.

[0046] Whenever radial compressive strength is mentioned in this document, it refers to the radial compressive strength measured as follows: A sample coreless roll is inserted into a standard force gauge with two parallel plates, a top plate and a bottom plate (large enough to clamp the coreless roll and apply pressure to the contact surface), which are, for example, metal plates. The coreless roll is placed on the bottom plate, and a plastic mandrel (e.g., a mandrel with a diameter in the range of 15 mm to 40 mm) is inserted into the inner hole of the coreless roll. Then, typically by moving the top and bottom plates toward each other (using a compression rate of 60 mm / min and, for example, using a force gauge with a load sensor of, for example, 200 N), the bottom and top plates are moved toward each other, and the pressure (in Newtons) required to be applied to the coreless roll is measured until the interior of the coreless roll begins to exert pressure on the mandrel. The pressure applied to the coreless roll (at which the interior of the coreless roll begins to exert pressure on the mandrel) is the radial compressive strength of the coreless roll. To obtain statistically significant results / measurements, at least five consecutive measurements may be required. To obtain reliable results, continuous measurements must be performed on separate rolls (from the same product series). Sample rolls need to be pre-modified, and measurements must be performed according to standard specification ISO 187:1985.

[0047] Therefore, the term "structured layer" is used to refer to a layer made by web forming, which has been treated to improve its properties, and is used to distinguish it from conventional pressed layers. Specifically, the shaped fabric is designed to selectively densify and create a strength network to produce a structured layer. In particular, web forming is performed on cotton paper (while it is still damp), and the cotton paper is dried, causing hydrogen bonding to occur to form a "structure". Compared to conventional pressed cotton paper layers, the process of manufacturing structured layers can be used to improve softness, bulk density, and absorbency at a higher strength.

[0048] For example, TAD layers are manufactured by selectively densifying the web and partially defining an unpressed bag that retains its initial volumetric density using woven knotting. When manufacturing TAD layers, the wet, unpressed web can be dehydrated using a vacuum chamber until approximately 25-30% solids remain (compared to approximately 38-42% when processed using a conventional pressing process). A molding step can be used to mold the wet web into a 3D morphology for the TAD fabric. If dry creping is used, this means a reduction in the Yankee surface contact area for creping adhesion (e.g., 18-30% contact area) compared to unstructured manufacturing processes, resulting in a reduction in the drying capacity of the Yankee dryer compared to the case of using unstructured cotton paper. Some TAD layers are manufactured using a single dryer layout, while others are manufactured using a dual dryer layout. Another option is to use multiple smaller dryers in series. Fabric sanding is frequently used to create a surface for increased Yankee contact.

[0049] UCTAD is a variant of TAD, where "UC" stands for Uncreased Sheet Paper. The manufacturing process of UCTAD allows for the elimination of the Yankee Dryer. However, the lack of creasing is a potential weakness for high softness grades. Compensation techniques, including fabric creasing, fabric design, and chemicals, are employed to improve the softness of crease-free sheets.

[0050] eTAD is another variant of TAD, where the "e" stands for energy saving because it avoids air penetration during drying. The wet paper web is pressed against a small dryer and then wet-creased, and / or quickly transferred to a TAD-type fabric with approximately 30-60% solids, then dried and creased using a Yankee dryer. No air is blown across the web during the drying process.

[0051] ATMOS (Advanced Tissue Molding System) is an alternative to structured tissue molding technology. The web profile generated by the structured forming line is used to initiate molding at low solids content. A high-strength, permeable belt press is used to dehydrate the sheet under a steam or hot exhaust shower, which is drawn into a vacuum chamber below the belt. At this stage, the web solids are in the range of approximately 15-35%. The dehydrated sheet is then molded and rapidly transferred to a TAD-like forming fabric, and then to a Yankee dryer (with a solids content of approximately 35%). ATMOS technology can be used to reduce energy consumption in manufacturing processes associated with TAD roller operations.

[0052] The NTT layer shares similarities with the ATMOS layer. Structured patterns are created using laser engraving on the NTT strip. The laser engraving process offers greater flexibility than woven TAD fabrics for creating interesting consumer patterns and achieving desired performance. According to NTT technology, initial compaction of the sheet during pressing can be avoided.

[0053] According to some embodiments, the tissue paper product has a (sheet) caliper measurement of at least 0.55 mm, at least 0.6 mm in some embodiments, and even at least 0.7 mm in others. These lower threshold values ​​on the caliper measurement can reach increasingly larger values ​​(indicated as lower threshold values ​​for caliper measurement), resulting in good customer satisfaction because customers expect the tissue paper product to have a minimum caliper measurement so that they feel comfortable handling the tissue paper product.

[0054] Returning to the coreless roll and tissue paper products according to this disclosure, in particular, the first layer may include a first embossing having a first height (h1) in the range of 0.2 mm to 2.0 mm.

[0055] The second layer may include a second embossing having a second height (h2) in the range of 0.2 mm to 2.0 mm.

[0056] An adhesive, such as a laminating adhesive, may be applied to the tip of the first embossing of the first layer and / or the tip of the second embossing of the second layer.

[0057] The first layer may include a third embossing with a third height (h3) less than the first height h1 (h1>h3). In other words, adhesive may be applied to the tip of the higher embossing (i.e., the embossing with a larger embossing height). The third height (h3) may be in the range of 0.1 mm to 1.2 mm.

[0058] The third embossing (if present) may have been formed by the same embossing roller used to form the first embossing, or alternatively, by different (heatable or non-heatable) embossing rollers.

[0059] According to some embodiments, the first embossing has been formed by a first heated embossing roller. If embossing is performed using the first heated embossing roller, i.e., if hot embossing is performed, this can promote higher tensile strength and / or higher absorbency compared to a reference product manufactured similarly without hot embossing (i.e., embossing without a heated embossing roller), without reducing the softness of the tissue paper product.

[0060] According to some embodiments, the second embossing has been formed by a second heated embossing roller. If embossing is performed using a second heated embossing roller, i.e., if hot embossing is performed, this can promote higher tensile strength and / or higher absorbency compared to a reference product manufactured similarly without hot embossing (i.e., embossing without a heated embossing roller), without (or with little to no) reducing the softness of the tissue paper product.

[0061] According to some embodiments, the third embossing has been formed by a third heated embossing roller. If embossing is performed using a third heated embossing roller, i.e., if hot embossing is performed, this can promote higher tensile strength and / or higher absorbency compared to a reference product that is similarly manufactured but without hot embossing (i.e., without embossing using a heated embossing roller), without (or with little to no) reducing the softness of the tissue paper product.

[0062] According to some embodiments, before being embossed, the first layer has been wetted with a certain amount of liquid (e.g., water), ranging from 2% to 12% of the basis weight of the first layer, or optionally from 4% to 10% of the basis weight of the first layer, wherein the liquid may optionally be provided with one or more additives, or wherein the first layer is not wetted with liquid before embossing.

[0063] The geometric mean tensile strength of coreless roll tissue paper products comprising two layers can range from 200 N / m to 500 N / m, optionally from 200 N / m to 370 N / m. Geometric mean tensile strength (GMT) is the square root of the product of machine-direction tensile strength (MDT) and cross-direction tensile strength (CDT). Whenever “tensile strength” is mentioned herein, the tensile strength discussed can be measured and compared as dry tensile strength according to standard EN ISO 12625-4:2016 (the above range refers to dry tensile strength) or as wet tensile strength according to standard ISO 12625-5:2017.

[0064] Dry strength is determined according to EN ISO 12625-4:2016, Tissue Paper and Tissue Products, Part 4: Determination of width-related breaking strength, elongation at break and tensile energy absorption. For illustrative purposes, the tensile testing apparatus used for the measurement has two 50 mm wide clamps. Each clamp can securely hold the specimen along a straight line (clamping line) across the entire width of the specimen without damage. The distance between the clamping lines is set to 100 mm. For a specific test, if the available length of the sample is less than 100 mm (e.g., toilet paper in the intersecting direction), the distance will be shortened. The tissue paper product to be measured, i.e., two single-layer or multi-layer products, is cut into 50 mm wide specimens with parallel edges. Each sheet is cut into two different types of specimens by cutting along the machine direction and the intersecting direction. The obtained specimens were then conditioned for at least 4 hours in an atmosphere of 23°C and 50% RH (relative humidity). The specimens to be measured were placed between clamps without any strain and to eliminate any observable relaxation. Initially, a pre-tension force of 25 cN was applied (elongation zero), and then the elongation rate between the clamps was kept constant at 5 cm / min. The maximum tensile force required to cause the specimen to break was obtained. Measurements were repeated with six specimens, and the obtained values ​​were averaged. The dry tensile strength was calculated using the following formula: Average dry tensile strength [N / m] = (Average maximum tensile force [N] / Initial width of specimen [mm]) × 10 < 3.

[0065] Wet strength was determined according to EN ISO 12625-5:2016 Tissue Paper and Tissue Products, Part 5: determination of width-related wet load at break, 2016. (Optionally, the following description follows the principles of DIN standards). For illustrative purposes, when experimentally verifying the wet strength of the product, tensile tests were performed using an electronic tensile testing apparatus (model 1122, Instron Corp., Canton, Mass., USA) with a Finch device at a constant elongation of 50 mm / min. To prepare the test strips, six samples were cut from raw tissue paper (single-layer) prepared with the longitudinal direction of the test strip coinciding with the machine direction (MD) or cross direction (CD), each sample having a length of 150 mm and a width of 50 mm. The free clamping length when using the Finch clamp was approximately 50 mm. The two ends of the test strip were secured in the clamps of the testing apparatus. The other end (ring) formed in this manner is placed around the needle and treated with distilled water at 23°C until fully saturated. The immersion depth of the ring formed by the test strip is at least 20 mm. The immersion time (immersion time) is 15 s, and the elongation is set to a constant (50±2) mm / min. The breaking strength of the sample immersed in distilled water is measured. Six test strips are measured at one time, and the results are expressed as an arithmetic mean. To ensure that the wet strength of the sample has been fully developed, which is especially necessary for samples where additional wet strength agents are used (e.g., by adding them to the mass) to enhance wet strength, the samples to be tested are always artificially aged before tensile testing. Aging is achieved by heating the sample to (80±1)°C for 30 minutes in an air-circulating drying chamber. Six test strips are measured at one time, and the results are expressed as an arithmetic mean.

[0066] Another aspect of the aforementioned objective is achieved by a coreless roll of a three-layered tissue paper product (e.g., a household towel) according to this disclosure. The coreless roll is made from a continuous web of tissue paper product spirally wound with a first end and a second end. The web of tissue paper product is wound to define an axially extending inner hole that is centrally positioned relative to the coreless roll, such that the first end is located outside the coreless roll and the second end is located at the inner hole.

[0067] The tissue paper product consists of three layers: a first layer, a second layer, and a third layer.

[0068] These three layers are bonded together. According to some embodiments, they can be bonded using adhesives (e.g., laminating adhesives) and / or mechanical bonding (e.g., edge embossing) to form a tissue paper product.

[0069] This tissue paper product comprises three layers: a first layer, a second layer, and a third layer, with the first layer being one of the outermost layers. In other words, the total number of layers in the tissue paper product is three. However, this does not mean that the tissue paper product cannot include other components (besides the layers), such as adhesives, additives, etc. It simply means that there are three layers. At least one of the three layers is an embossed layer. One, two, or all three layers can be embossed layers.

[0070] The basis weight of the tissue paper product is 45g / m². 2 Up to 75g / m 2 Within the range.

[0071] This tissue paper product has a geometric mean tensile strength of at least 250 N / m.

[0072] The first, second, and third layers are each made of conventional wet-pressed (CWP) paper.

[0073] The first, second, and third layers have been embossed into a nested pattern.

[0074] The outer diameter of the coreless roll ranges from 95 to 150 mm, the inner diameter ranges from 20 to 50 mm, and the density of the coreless roll ranges from 65 to 125 kg / m³. 3 Within the range.

[0075] The caliper measurement ratio of the roll is in the range of 10% to 45%. Caliper measurement ratio (c) s -c t ) / c t It is achieved by measuring the standard caliper value c of tissue paper products as defined by standard ISO-12625-3:2014. s Theoretical caliper measurement value c for cotton paper products t The difference between them divided by the theoretical caliper measurement c t The theoretical caliper measurement value c was obtained from this. t Defined as the ratio between the basis weight and roll density of a tissue paper product.

[0076] According to some embodiments, the caliper measurement of the tissue paper product is at least 0.7 mm.

[0077] According to some embodiments, at least one of the three layers has been embossed with a heated embossing roller. However, two or all three layers can be embossed with a heated embossing roller.

[0078] The coreless roll can have a cross-direction (CD) wet stretch of at least 40 N / m, and optionally at least 45 N / m.

[0079] The third layer can be positioned between the first and second layers.

[0080] The first layer may include a first embossing having a first height (h1) in the range of 0.2 mm to 2.0 mm.

[0081] The second layer may include a second embossing having a second height (h2) in the range of 0.2 mm to 2.0 mm.

[0082] An adhesive, such as a laminating adhesive, can be applied to the tip of the first embossing of the first layer and / or the tip of the second embossing of the second layer.

[0083] The first layer may include a third embossing having a third height (h3) less than the first height h1 (h1>h3). The third height (h3) may be in the range of 0.1mm to 1.2mm.

[0084] According to some embodiments, the third layer is not embossed before the layer bonding. Sometimes, the third layer (intermediate layer) may be referred to as an unembossed layer. "Unembossed" means that the third layer is not pre-embossed before the final layer bonding. That is, the third layer may no longer be flat after layer bonding, but it was not embossed beforehand using an embossing roller. According to some embodiments, the third layer is partially embossed at the point where it is bonded to the first or second layer.

[0085] The aforementioned coreless rolls of tissue paper products made of three layers can have a high caliper value ratio combined with high geometric mean tensile strength. Nested structures can facilitate this and allow for the avoidance of the need for forced use of hybrid structures (requiring at least one expensive structuring layer) or heated embossing or specific embossing designs to produce good coreless rolls with consumer-acceptable performance.

[0086] Due to their high caliper strength, the aforementioned coreless rolls are robust in terms of handling and storage performance.

[0087] Coreless rolls of the aforementioned three-layered tissue paper products can possess exceptionally high radial compressive strength. Specifically, the radial compressive strength of such rolls can be 20 N or greater, or even 25 N or greater, or even 30 N or greater. These are robust and meet the requirements for, for example, toilet paper rolls. Therefore, they can achieve customer satisfaction.

[0088] According to some embodiments, the first layer and the third layer have been embossed together to form a first embossing on the first layer and the third layer.

[0089] According to some embodiments, the third embossing is formed only on the first layer but not on the third layer, or, optionally, the first and third layers have been embossed together to form the third embossing on the first and third layers.

[0090] According to some embodiments, the first embossing has been formed by a first heated embossing roller. If embossing is performed with the first heated embossing roller, i.e., if hot embossing is performed, this can promote higher tensile strength and / or higher absorbency compared to a reference product that is similarly manufactured but not hot embossed (i.e., embossed without a heated embossing roller), without reducing the softness of the tissue paper product.

[0091] According to some embodiments, the second embossing has been formed by a second heated embossing roller. If embossing is performed using a second heated embossing roller, i.e., if hot embossing is performed, this can promote higher tensile strength and / or higher absorbency compared to a reference product that is similarly manufactured but not hot-embossed (i.e., embossing without heated embossing rollers), without reducing the softness of the tissue paper product.

[0092] According to some embodiments, the third embossing has been formed by either the first heated embossing roller or the third heated embossing roller. If embossing is performed using the third heated embossing roller, i.e., if hot embossing is performed, this can promote higher tensile strength and / or higher absorbency compared to a reference product that is similarly manufactured but not hot-embossed (i.e., embossing without heated embossing rollers), without reducing the softness of the tissue paper product.

[0093] According to some embodiments, the first layer and the third layer have been embossed together to form a first embossing on the first layer and the third layer.

[0094] According to some embodiments, the third embossing is formed only on the first layer and not on the third layer. According to other embodiments, the first and third layers have been embossed together to form the third embossing on both the first and third layers.

[0095] The third layer (i.e., the intermediate layer) may include a fourth embossing with a fourth height (h4) ranging from 0.2 mm to 2.0 mm. The third layer may be embossed separately from the first and second layers. According to some embodiments, the fourth embossing has been formed by a fourth heated embossing roller.

[0096] The third embossing (if present) can be formed by the same heated embossing roller used to form the first embossing, or alternatively, by different (heatable or non-heatable) embossing rollers.

[0097] According to some embodiments, prior to embossing, the first layer is wetted with a certain amount of liquid (e.g., water), for example, 2% to 12% of the first layer's basis weight or optionally 4% to 10% of the first layer's basis weight. The liquid may have been provided with one or more additives, or the first layer may not need to be wetted with liquid prior to embossing.

[0098] Coreless rolls of the aforementioned three-layered tissue paper products can possess exceptionally high radial compressive strength. Specifically, the radial compressive strength of such rolls can be 30 N or greater, or even 40 N or greater, or even 45 N or greater. These are robust and meet requirements for, for example, household towels. This performance can be further improved by specifying increasingly narrower grammage ranges for three-layered tissue paper products.

[0099] The geometric mean tensile strength of a three-layer coreless roll of tissue paper can be in the range of 250 N / m to 600 N / m, optionally 250 N / m to 530 N / m, or 250 N / m to 460 N / m (these ranges are related to dry tensile strength).

[0100] Another aspect of this disclosure relates to a coreless roll of a tissue paper product, such as a household towel, having the following structure. The coreless roll is made of a continuous web of tissue paper product spirally wound with a first end and a second end. The web of tissue paper product is wound to define an axially extending inner hole that is centrally positioned relative to the coreless roll, such that the first end is located outside the coreless roll and the second end is located at the inner hole.

[0101] The tissue paper product comprises at least two layers, including at least a first layer and a second layer, wherein the first layer is one of the outermost layers of the tissue paper product. The total number of layers in the tissue paper product is between 2 and 4. The layers between 2 and 4 are laminated, optionally with adhesives, such as laminating adhesives, and / or mechanically bonded, such as edge embossing, to form the tissue paper product.

[0102] The tissue paper product has a geometric mean tensile strength of at least 200 N / m.

[0103] The basis weight of the tissue paper product is 35g / m². 2 Up to 75g / m 2 Within the range. The layers have been embossed to create a nested effect.

[0104] The outer diameter of the coreless winding ranges from 95 to 150 mm. The inner diameter ranges from 20 to 50 mm. The density of the coreless winding ranges from 65 to 120 kg / m³. 3 Within the range.

[0105] If the total number of layers is 2, the roll caliper measurement ratio is in the range of 40%-70%; if the total number of layers is 3, the roll caliper measurement ratio is in the range of 10%-45%. The caliper measurement ratio (c) s -c t ) / c t By using the standard caliper measurement value c of tissue paper products as defined by standard ISO-12625-3:2014 s Theoretical caliper measurement value c for cotton paper products t The difference between them divided by the theoretical caliper measurement ct To obtain. The theoretical caliper measurement value c t Defined as the ratio between the basis weight of a tissue paper product and the density of the roll.

[0106] The radial compressive strength of the coreless roll is 20 N or higher, optionally 25 N or higher, or 30 N or higher.

[0107] Coreless rolls containing the aforementioned tissue paper products can possess exceptionally high radial compressive strength. Specifically, the radial compressive strength of such rolls can be 20 N or greater, or even 25 N or greater, or even 30 N or greater. These are robust and meet requirements for, for example, household towels. This performance can be further improved by specifying increasingly narrower grammage ranges for triple-layer tissue paper products.

[0108] The geometric mean tensile strength of the three-layer coreless roll tissue paper products can be in the range of 200 N / m to 600 N / m, optionally 200 N / m to 530 N / m or 200 N / m to 460 N / m.

[0109] In any embodiment of the aforementioned tissue paper product (or any combination of embodiments, the features of the different embodiments are not incompatible so far) (regardless of the number of layers, etc., and regardless of which of the above aspects is chosen), at least a portion, optionally the entire innermost coil, of the absorbent material at the second end of the coreless roll may include a stabilizing coating composition. This can help promote good radial and / or axial stability of the coreless roll.

[0110] The coating composition may include at least one of the following: polymers containing oxygen and / or nitrogen atoms, nonionic polymers such as nonionic cellulose ethers, and polyether polyols.

[0111] The coating composition may contain water.

[0112] When the coating composition includes a nonionic polymer, the ion requirement can be in the range of -1000 to +100 µeq / g, or -500 to +50 µeq / g, or -50 to 0 µeq / g.

[0113] The coating composition may be applied only to one side of the innermost coil. This side may be the side facing the axially extending inner hole.

[0114] Another aspect of this disclosure relates to a method for manufacturing a coreless roll of tissue paper product, such as a household towel, the tissue paper product being made of two layers. The method includes the following steps: - Provides a first layer of conventional wet-pressed paper (CWP) and a second layer of conventional wet-pressed paper (CWP). - Emboss the two layers to make them nested and laminate the two layers, optionally using an adhesive, such as a laminating adhesive, and / or using mechanical bonding, such as edge embossing, to form a layer with a basis weight of 35 g / m². 2 Up to 55g / m 2 The range of cotton paper products with a geometric mean tensile strength of at least 200 N / m and a caliper measurement ratio in the range of 40% to 70%; - The tissue paper product is spirally wound onto a mandrel to form a coreless roll and define an axially extending inner hole, with a first end of the tissue paper product located outside the coreless roll and a second end located at the inner hole; and - Remove the mandrel; The coreless winding has an outer diameter ranging from 95 to 150 mm, an inner diameter ranging from 20 to 50 mm, and a density ranging from 70 to 90 kg / m³. 3 Within the range.

[0115] The caliper measurement ratio can be adjusted by adjusting the embossing pressure during the manufacturing process.

[0116] Coreless rolls manufactured by this method can have the same advantages as the two-layer coreless rolls described above. In other words, the features of the coreless rolls of any of the above embodiments are converted into corresponding features of the embodiments of this method, and vice versa. For the sake of brevity, the benefits that may be associated with specific features of the product embodiments will not be discussed with respect to the corresponding method claims; instead, reference will now be made to the corresponding paragraphs of the description relating to the product embodiments on a general basis.

[0117] The caliper readings of the manufactured tissues can be at least 0.7 mm.

[0118] According to some embodiments, the method includes the step of hot embossing at least one of the two layers.

[0119] The method may include the step of embossing a first layer using a first embossing roller having a first embossing protrusion to form a first embossing having a first height (h1) in the range of 0.2 mm to 2.0 mm.

[0120] The method may include the step of embossing a second layer using a second embossing roller having a second embossing protrusion to form a second embossing having a second height (h2) in the range of 0.2 mm to 2.0 mm.

[0121] According to some embodiments, the heated embossing roller further includes a third embossing protrusion, and the embossing of the first layer may include forming both the first and third embossings on the first layer. According to other embodiments, the method includes the step of embossing the first layer with a third embossing roller having the third embossing protrusion to form a third embossing. In other words, the second type of embossing can be formed on the first layer using the same embossing roller as used for the first embossing, or they can be formed using another embossing roller. Similar statements also apply to more types of embossing (different types refer to embossings with different shapes and / or different embossing heights, etc.). The third embossing protrusion may be formed with a height (h3) ranging from 0.1 mm to 1.2 mm.

[0122] Another aspect of this disclosure relates to a method for manufacturing coreless rolls of tissue paper products, such as household towels, the tissue paper product being made of three layers. The method includes the following steps: - Provides a first layer, a second layer, and a third layer of conventional wet-pressed paper (CWP); - Embossing the three layers to make them nested and layered together, optionally using adhesives such as laminating adhesives, and / or using mechanical bonding, such as edge embossing, to form a layer with a basis weight of 45 g / m². 2 Up to 75g / m 2 The range of cotton paper products with a geometric mean tensile strength of at least 250 N / m and a caliper measurement ratio in the range of 10% to 40%; - The tissue paper product is spirally wound on a mandrel to form a coreless roll and define an axially extending inner hole, wherein a first end of the tissue paper product is located outside the coreless roll, and a second end is located at the inner hole; and - Remove the mandrel; The outer diameter of the coreless winding ranges from 95 to 150 mm, the inner diameter ranges from 20 to 50 mm, and the density ranges from 65 to 125 kg / m³. 3 Within the range.

[0123] The caliper measurement ratio can be adjusted by adjusting the embossing pressure during the manufacturing process.

[0124] The tissue paper products manufactured by this method can have similar benefits to the three-layer tissue paper products described above. In other words, the features of the tissue paper products of any of the above embodiments are converted into the corresponding features of the method embodiments, and vice versa. For the sake of brevity, the benefits that may be associated with specific features of the product embodiments will not be discussed with respect to the corresponding method claims; instead, reference will now be made to the relevant paragraphs of the description relating to the product embodiments on a general basis.

[0125] The caliper reading of the manufactured tissue paper can be at least 0.7 mm.

[0126] The method may include embossing a first layer using a first embossing roller having a first embossing protrusion to form a first embossing having a first height (h1) in the range of 0.2 mm to 2.0 mm.

[0127] The method may include embossing a second layer using a second embossing roller having a second embossing protrusion to form a second embossing having a second height (h2) in the range of 0.2 mm to 2.0 mm.

[0128] The first, second, and third layers are combined such that the third layer is located between the first and second layers.

[0129] According to some embodiments, the heated embossing roller further includes a third embossing protrusion, and the step of embossing the first layer forms both the first and third embossings on the third layer. The embossing formed by the third embossing can have a height (h3) in the range of 0.1 mm to 1.2 mm. According to other embodiments, the method includes the step of embossing the first layer using a third embossing roller with the third embossing protrusion to form a third embossing. The embossing formed by the third embossing can have a height (h3) in the range of 0.1 mm to 1.2 mm. In other words, second-type embossings can be formed on the first layer using the same embossing roller used for the first embossing, or they can be formed using another embossing roller. Similar statements also apply to more types of embossings (different types refer to embossings with different shapes and / or different embossing heights, etc.).

[0130] According to some embodiments, the third layer may not be embossed. In other words, the third layer can be a flat layer in the sense that it has not been (pre-)embossed by an embossing roller before the layer bonding occurs. In the sense that layer bonding can remove the flatness of the third layer, it does not need to be flat after layer bonding.

[0131] The first and third layers can be embossed together using a first embossing roller to form a first embossing on the first and third layers.

[0132] According to some embodiments, the third embossing is formed only on the first layer and not on the third layer. According to other embodiments, the first and third layers are embossed together to form the third embossing on both the first and third layers.

[0133] The first embossing on the first layer can be formed by the first heated embossing roller.

[0134] The second embossing on the second layer can be formed by a second heated embossing roller.

[0135] The third embossing can be formed by a heated embossing roller or a third heated embossing roller.

[0136] The method may include the step of forming a fourth embossing with a fourth height (h4) on a third layer using a fourth embossing roller, the fourth height (h4) being in the range of 0.2 mm to 2.0 mm, wherein the third layer is embossed separately from the first and second layers.

[0137] The fourth embossing can be formed by a fourth heated embossing roller.

[0138] This disclosure also relates to coreless rolls of tissue paper products manufactured according to any (or any combination thereof, provided they are not incompatible) embodiments of the methods of this disclosure.

[0139] Additional advantages and features of this disclosure will become apparent from the following description of specific embodiments. These advantages and features can be implemented individually or in combination with one or more features discussed above, provided that these features do not contradict each other. Attached Figure Description

[0140] To better understand this disclosure and to illustrate how to implement it, reference is now made to the accompanying drawings, which, by way of example only, contain: A description is given with reference to the accompanying drawings, in which: Figure 1 This is a perspective view of a coreless roll according to this disclosure; Figure 2 This is a schematic diagram (partial) of an embodiment of a manufacturing apparatus for manufacturing a coreless roll according to the present disclosure using a first embodiment of the method according to the present disclosure; Figure 3 This is a schematic diagram (partial) of an embodiment of a manufacturing apparatus for manufacturing a coreless roll according to the present disclosure using a second embodiment of the method according to the present disclosure; Figure 4 This is a schematic diagram (partial) of an embodiment of a manufacturing apparatus for manufacturing a coreless roll according to the present disclosure using a third embodiment of the method according to the present disclosure; and Figure 5-7 Examples of tissue paper products that are part of the coreless roll according to this disclosure are described. Detailed Implementation

[0141] Figure 1 This is a schematic diagram of the coreless roll 1 according to this disclosure.

[0142] Figure 1 Coreless roll 1 represents an embodiment of a different tissue paper product having two or three layers. All layers in these embodiments are made of conventional wet-pressed (CWP) paper.

[0143] Figure 1 One embodiment is a household towel roll including a tissue paper product comprising different sheets 2a, 2b that can be easily separated along a perforation line 3. However, other embodiments may not include such a perforation line.

[0144] Figure 1 The coreless roll 1 is made of a spirally wound continuous web of a tissue paper product having a first end and a second end, the web of the tissue paper product being wound to define an axially extending inner hole that is centrally positioned relative to the coreless roll 1, such that the first end is located outside the coreless roll 1 and the second end is located at the inner hole.

[0145] The outer diameter D1 of coreless roll 1 is in the range of 95 to 150 mm. The inner diameter D2 of roll 1 is in the range of 20 to 50 mm. The density of coreless roll 1 is in the range of 65 to 125 kg / m³. 3 Within the range (a narrower range is indicated above for tissue paper products of the corresponding number of layers).

[0146] Figure 1 The tissue paper products in this embodiment use adhesives (lamination adhesives) for lamination. However, this is by no means a limitation. In other embodiments, the layers can be laminated, for example, using mechanical bonding (e.g., edge embossing). In other words, adhesives are not required, and other embodiments can be "adhesive-free." Another option is to use both adhesives and mechanical bonding.

[0147] The basis weight of tissue paper products depends on the number of layers. It ranges from 35 to 75 g / m². 2 Within the range (a narrower range for the corresponding layer is indicated above).

[0148] The caliper measurement ratio of the roll is in the range of 10% to 70% (a narrower range is indicated above for the corresponding number of layers), where the caliper measurement ratio (c) s -c t ) / c t It is achieved by measuring the standard caliper value c of tissue paper products as defined by standard ISO-12625-3:2014. s Theoretical caliper measurement value c for cotton paper products t The difference between them divided by the theoretical caliper measurement c t The obtained, and theoretical caliper measurement value c t It is defined as the ratio between the basis weight of a tissue paper product and the density of the roll. This ratio can be easily changed by altering the embossing pressure during the manufacturing process of the corresponding tissue paper product.

[0149] Figure 1 The radial compressive strength of the coreless roll 1 is at least 30 N or greater. However, according to other embodiments, it is at least 20 N or greater, or at least 25 N or greater. This provides robustness for household towels (e.g., achieving customer satisfaction, but also for packaging purposes, etc.), and this is achieved despite the fact that roll 1 is coreless. Because the roll is coreless, waste is reduced, and the roll in question can be considered environmentally friendly.

[0150] The caliper measurement of Roll 1 (sheet) is at least 0.7 mm.

[0151] Figure 2 This is a schematic diagram of a manufacturing apparatus and embodiment for manufacturing a coreless roll according to the present disclosure using a first embodiment of the method according to the present disclosure.

[0152] Figure 2 The box 200 in the diagram schematically represents the manufacturing equipment. Figure 2 Any components previously used that are shown in more detail below. For example, box 200 may include unfolding rollers for unfolding the first layer 10 and the second layer 20.

[0153] The first layer 10 and the second layer 20 are made of conventional wet-pressed (CWP) paper. Figure 2 In the case of the embodiments, they are single-layered. However, for example, in other embodiments, the first layer 10 may be replaced, for example, by two layers embossed together.

[0154] The first layer 10 is embossed between a non-heatable embossing roller 40 (which can be replaced by a heatable embossing roller, for example, in some embodiments, the heatable embossing roller can be heated to a steady-state temperature in the range of 80°C to 240°C) and a counter roller 35. An adhesive supply unit having a glue chamber 80 is arranged adjacent to the roller 40. A coating roller 105 is used to uniformly transfer the adhesive (measured by cavities etched in an anilox roller located between the glue chamber 80 and the coating roller 105) to the first layer 10 prior to layer bonding.

[0155] The second layer 20 embosses between the embossing roller 50 and the counter roller 60. In this case, the roller 50 is not heated, but it can be a heated embossing roller 50, and in some embodiments, it can be heated, for example, to a steady-state temperature in the range of 80°C to 240°C.

[0156] Then, the first layer 10 and the second layer 20 are laminated between the embossing roller 40 and the bonding roller 70. The laminated tissue paper product 110, comprising at least two layers, is then further conveyed.

[0157] Box 450 indicates Figure 2 Any components used after those components described in more detail above in the manufacturing equipment. In particular, box 450 may include a winding unit for winding the manufactured tissue paper product 110, as well as other units for manufacturing coreless rolls.

[0158] Figure 3 This is a schematic diagram (partial) of an embodiment of a manufacturing apparatus for manufacturing a coreless roll according to the present disclosure using a second embodiment of the method according to the present disclosure.

[0159] Figure 3 Box 200 schematically represents any component of the manufacturing equipment used prior to the later stages shown in more detail. For example, box 200 may include unfolding rollers for unfolding the first layer 15 and the second layer 25.

[0160] A first layer 15 and a second layer 25 are provided to a pre-embossing station 300. The pre-embossing station 300 includes rollers 303 and 304 for pre-embossing the first layer 15 and rollers 301 and 302 for pre-embossing the second layer 25. In some embodiments, one or any selection of rollers 301, 302, 303, and 304 may be replaced by a heatable embossing roller, wherein the heatable embossing roller can, for example, be heated to a steady-state temperature in the range of 80°C to 240°C.

[0161] The first layer 15 is then conveyed toward the main embossing and lamination station. The first layer 15 is specifically embossed between the embossing roller 40 and the counter roller 35. An adhesive supply unit with a glue chamber 80 is disposed adjacent to the embossing roller 40. The coating roller 105 is used to uniformly transfer the adhesive (measured by cavities etched on the anilox roller located between the glue chamber 80 and the coating roller 105) to the first layer 15 before the final lamination is performed.

[0162] The second layer 25 is conveyed toward rollers 50 and 60 and embossed between embossing roller 50 and roller 60. The layering of the first layer 15 and the second layer 25 is carried out between embossing roller 40 and bonding roller 70. The tissue paper product 110, comprising at least two layers, is then further conveyed.

[0163] Box 450 indicates Figure 3 Any components of the manufacturing equipment used after the steps described so far. In particular, block 450 may include a winding unit for manufacturing the tissue paper product 110, as well as other units for manufacturing coreless rolls.

[0164] Figure 4 An apparatus for performing a method according to the present disclosure is described, which is used to manufacture coreless rolls comprising a tissue paper product having at least three layers made of CWP.

[0165] Most of the content shown is similar to the above about Figure 3 The content explained. Therefore, refer to the corresponding explanation. The difference is that a third layer 26 is additionally provided. It is guided to the embossing roller 40, where it is further conveyed together with the first layer 15. Then, the first layer 15 and the third layer 26 are combined with the second layer 25 between the embossing roller 40 and the bonding roller 70.

[0166] exist Figures 2 to 4In each case, the various embodiments corresponding to the figures discussed may include one or more heatable embossing rollers 50.

[0167] Figures 5 to 7 Several embodiments of a tissue paper product that is spirally wound to form a coreless roll according to the present disclosure are described.

[0168] Figure 5 The tissue paper product consists of two layers: top layer 1 and bottom layer 2. Both top layer 1 and bottom layer 2 include embossing.

[0169] Top layer 1 and bottom layer 2 are both made of conventional wet-pressed (CWP) paper and constitute the “first layer” and “second layer” in this application.

[0170] Figure 5 The basis weights of the tissue paper products range from 35 to 55 g / m². 2 Within the range.

[0171] Figure 6 and 7 The embodiment includes exactly three layers: top layer 1, bottom layer 2, and middle layer 3.

[0172] All three layers (1, 2, and 3) are made of conventional wet-pressed (CWP) paper.

[0173] exist Figure 6 In this embodiment, the top layer 1 and the middle layer 3 have been embossed together. Conversely, in Figure 7 In the example embodiment, the bottom layer 2 and the middle layer 3 have been embossed together.

[0174] Figure 6 and 7 The basis weights of the tissue paper products range from 45 to 75 g / m². 2 Within the range.

[0175] In the following sections, numerous experimental results obtained based on coreless rolls according to embodiments of the present disclosure will be discussed.

[0176] Examples of coreless rolls made from two layers of tissue paper. (use Figure 2 The manufacturing equipment of the type shown manufactures coreless rolls of a two-layer tissue paper product comprising two CWP layers. The outer diameter of the coreless roll is 130 mm. In particular, an example according to this disclosure was manufactured, and a comparative example was manufactured in which the layers are laminated to form a non-nested structure.

[0177] In the first set of tests, two CWP layers (household towel base sheet) with a basis weight of 21.5 g and a geometric mean tensile (GMT) strength of about 215 N / m were used to manufacture a coreless roll according to the present disclosure, which comprises a household towel made of two layers.

[0178] In the second set of tests, two CWP layers (household towel base sheet) with a basis weight of 24.7 g and a geometric mean tensile (GMT) strength of about 258 N / m were used to manufacture a coreless roll according to the present disclosure, which comprises a household towel made of the two layers.

[0179] The roll is made with an outer diameter of 130mm and an inner core diameter of 40mm. The sheet is made with a length and width of 230mm.

[0180] Comparative examples 1 and 2 are fabricated. Furthermore, comparative examples 3 and 4 are fabricated without nested structures.

[0181] Table 1 below summarizes the results of the first group of experiments (Examples 1-4), the second group of experiments (Examples 5 and 6), and the comparison of Examples 1-4. The embossing load of the top layer was 27 kg. The embossing load of the bottom layer was 17 kg.

[0182] Table 1 shows the basis weight of the manufactured coreless rolls (unit: gsm, representing g / m). 2 The values ​​of roll density, caliper ratio, number of sheets, thickness, geometric mean tensile strength (“GMT”), and radial compressive strength are also considered.

[0183] As can be seen from Table 1, the coreless embodiments according to this disclosure have high geometric mean tensile strength, combined with a high caliper value ratio. The nested structure can facilitate this and allows for the avoidance of the need for a hybrid structure (requiring at least one expensive structuring layer) or heated embossing or specific embossing designs to manufacture good coreless rolls with consumer-acceptable performance.

[0184] Due to their high strength, these coreless coils exhibit robust performance in handling and storage. Therefore, they can achieve high customer satisfaction.

[0185] Example of a coreless roll made from three-layer tissue paper products. In another set of tests, embodiments of a three-layer coreless roll of household towels according to this disclosure were manufactured, along with a comparative product (with a non-nested structure). Examples 1-3 were manufactured using three conventional CWP substrate sheets with a basis weight of 18 gsm and a GMT of approximately 223 N / m. Coreless rolls of household towels with an outer diameter of 130 mm and an inner core diameter of 40 mm were produced. The sheet length and width were 230 mm.

[0186] Comparative Example 1 was manufactured using three standard CWP substrate sheets with a basis weight of 18 gsm and a GMT of approximately 223 N / m. Furthermore, Comparative Example 2 was manufactured without any nested structures.

[0187] The embossing load of the top layer is 27 kg. The embossing load of the bottom layer is 25 kg.

[0188] Table 2 summarizes the results of these further experiments.

[0189] Table 2

[0190] As can be seen from Table 2, the coreless embodiments of this disclosure, combined with a high caliper ratio, exhibit high geometric mean tensile strength. The nested structure facilitates this and allows for the avoidance of the need for forced hybrid structures (requiring at least one expensive structuring layer) or heated embossing or specific embossing designs to manufacture good coreless rolls with consumer-acceptable performance.

[0191] Due to their high strength, these coreless coils exhibit robust performance in handling and storage. Therefore, they can achieve high customer satisfaction.

[0192] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed devices and systems without departing from the scope of this disclosure. Other aspects of this disclosure will be apparent to those skilled in the art in light of the description and practice of the features disclosed herein. This specification and examples are intended to be illustrative only. Many additional changes and modifications are possible and are to be understood to fall within the framework of this disclosure.

Claims

1. A coreless roll of a tissue paper product, the coreless roll being made from a continuous web of tissue paper product helically wound with a first end and a second end, the web of the tissue paper product being wound to define an axially extending inner hole centrally positioned relative to the coreless roll, such that the first end is located outside the coreless roll and the second end is located at the inner hole. The tissue paper product comprises two layers, namely a first layer and a second layer, which are laminated together to form the tissue paper product. The basis weight of the tissue paper product is between 35 and 55 g / m². 2 Within the range, The tissue paper product has a geometric mean tensile strength of at least 200 N / m, and wherein The first and second layers are made of conventional wet-pressed (CWP) paper. The first and second layers have been embossed into a nested pattern. The outer diameter of the coreless roll is in the range of 95 to 150 mm, the diameter of the inner hole is in the range of 20 to 50 mm, and the density of the coreless roll is in the range of 70 to 90 kg / m³. 3 Within the range, and The caliper measurement ratio of the roll is in the range of 40% to 70%. The caliper measurement ratio (c) s -c t ) / c t It is determined by measuring the standard caliper value c of the tissue paper product as defined by standard ISO-12625-3:2014. s The theoretical caliper value c of the cotton paper product t The difference between them divided by the theoretical caliper measurement c t And what was obtained, and The theoretical caliper measurement value c t It is defined as the ratio between the basis weight of the tissue paper product and the density of the roll.

2. The coreless roll of the tissue paper product according to claim 1, wherein the tissue paper product is a household towel.

3. The coreless roll of the tissue paper product according to claim 1, wherein the first layer and the second layer are bonded together using an adhesive and / or a mechanical bonding method.

4. The coreless roll of the tissue paper product according to claim 3, wherein the adhesive is a laminating adhesive and the mechanical bonding is edge embossing.

5. The coreless roll of the cotton paper product according to claim 1, wherein the theoretical caliper value of the cotton paper product is at least 0.7 mm.

6. The coreless roll of the tissue paper product according to any one of claims 1-5, wherein at least one of the two layers has been embossed using a heated embossing roller.

7. The coreless roll of the tissue paper product according to any one of claims 1-5, The first layer includes a first embossing having a first height (h1), the first height (h1) being in the range of 0.2 mm to 2.0 mm. The adhesive is applied to the tip of the first embossed pattern in the first layer. The second layer includes a second embossing having a second height (h2) ranging from 0.2 mm to 2.0 mm. At least a portion of the second embossing is nested within at least a portion of the first embossing.

8. The coreless roll of the tissue paper product according to claim 7, wherein the adhesive is a laminating adhesive.

9. The coreless roll of the tissue paper product according to claim 7, wherein the first layer includes a third embossing having a third height (h3) less than the first height (h1) (h1>h3).

10. The coreless roll of the tissue paper product according to claim 9, The first embossing has been formed by a first heated embossing roller, and the third embossing has been formed by the first heated embossing roller. And / or wherein the second embossing has been formed by a second heated embossing roller, And / or wherein the third embossing has been formed by a third heated embossing roller, and / or among them, The first layer is wetted with a certain amount of liquid before being embossed, the amount of liquid being in the range of 2% to 12% of the basis weight of the first layer, or the first layer is not wetted with liquid before being embossed.

11. The coreless roll of the tissue paper product according to claim 10, wherein the liquid is water.

12. The coreless roll of the tissue paper product according to claim 10, wherein the amount of liquid is in the range of 4% to 10% of the basis weight of the first layer.

13. The coreless roll of the tissue paper product according to claim 10, wherein the liquid is provided with one or more additives.

14. A coreless roll of a tissue paper product, the coreless roll being made of a continuous web of tissue paper product helically wound with a first end and a second end, the web of the tissue paper product being wound to define an axially extending inner hole centrally positioned relative to the coreless roll, such that the first end is located outside the coreless roll and the second end is located at the inner hole. The tissue paper product comprises three layers: a first layer, a second layer, and a third layer, which are laminated together to form the tissue paper product. The basis weight of the tissue paper product is 45g / m³. 2 Up to 75g / m 2 Within the range, The tissue paper product has a geometric mean tensile strength of at least 250 N / m. The first, second, and third layers are made of conventional wet-pressed (CWP) paper. The first, second, and third layers are embossed in a nested pattern. The outer diameter of the coreless roll is in the range of 95 to 150 mm, the diameter of the inner hole is in the range of 20 to 50 mm, and the density of the coreless roll is in the range of 65 to 125 kg / m³. 3 Within the range, The caliper measurement ratio of the roll is in the range of 10% to 45%. The caliper measurement ratio (c) s -c t ) / c t It is determined by measuring the standard caliper value c of the tissue paper product as defined by standard ISO-12625-3:2014. s The theoretical caliper value c of the cotton paper product t The difference between them divided by the theoretical caliper measurement value c t And what was obtained, and The theoretical caliper measurement value c t It is defined as the ratio between the basis weight of the tissue paper product and the density of the roll.

15. The coreless roll of the tissue paper product according to claim 14, wherein the tissue paper product is a household towel.

16. The coreless roll of the tissue paper product according to claim 14, wherein the three layers are bonded together using adhesives and / or mechanical bonding.

17. The coreless roll of the tissue paper product according to claim 16, wherein the adhesive is a laminating adhesive and the mechanical bonding is edge embossing.

18. The coreless roll of the tissue paper product according to claim 14, wherein the theoretical caliper value of the tissue paper product is at least 0.7 mm.

19. The coreless roll of the tissue paper product according to any one of claims 14-18, wherein at least one of the three layers has been embossed using a heated embossing roller.

20. The coreless roll of the tissue paper product according to any one of claims 14-18, wherein the coreless roll of the tissue paper product has a cross-direction (CD) wet tensile strength of at least 40 N / m.

21. The coreless roll of the tissue paper product according to claim 20, wherein the coreless roll of the tissue paper product has a cross-direction (CD) wet tensile strength of at least 60 N / m.

22. The coreless roll of the tissue paper product according to claim 20, wherein the coreless roll of the tissue paper product has a cross-direction (CD) wet tensile strength of at least 80 N / m.

23. The coreless roll of the tissue paper product according to any one of claims 14-18, wherein the third layer is positioned between the first layer and the second layer. The first layer includes a first embossing having a first height (h1), the first height (h1) being in the range of 0.2 mm to 2.0 mm. The adhesive is applied to the tip of the first embossed pattern in the first layer. The second layer includes a second embossing having a second height (h2) in the range of 0.2 mm to 2.0 mm.

24. The coreless roll of the tissue paper product according to claim 23, wherein the adhesive is a laminating adhesive.

25. The coreless roll of the tissue paper product according to claim 23, wherein the first layer includes a third embossing having a third height (h3) less than the first height (h1) (h1>h3).

26. The coreless roll of the tissue paper product according to claim 25, wherein the first layer and the third layer are embossed together to form the first embossing on the first layer and the third layer, and in, The third embossing is formed only on the first layer but not on the third layer, or the first layer and the third layer are embossed together to form the third embossing on the first layer and the third layer.

27. The coreless roll of the tissue paper product according to claim 26, The first embossing has been formed by a first heated embossing roller, and / or The second embossing has been formed by a second heated embossing roller, and / or The third embossing has been formed by the first heated embossing roller or the third heated embossing roller, and / or in, The first layer is wetted with a certain amount of liquid before embossing, the amount of liquid being in the range of 2% to 12% of the basis weight of the first layer, or the first layer is not wetted with liquid before embossing.

28. The coreless roll of the tissue paper product according to claim 27, wherein the liquid is water.

29. The coreless roll of the tissue paper product according to claim 27, wherein the amount of liquid is in the range of 4% to 10% of the basis weight of the first layer.

30. The coreless roll of the tissue paper product according to claim 27, wherein the liquid is provided with one or more additives.

31. The coreless roll of the tissue paper product according to any one of claims 14-18, wherein the coreless roll has a radial compressive strength of 20 N or greater.

32. The coreless roll of the tissue paper product according to claim 31, wherein the coreless roll has a radial compressive strength of 25 N or greater.

33. The coreless roll of the tissue paper product according to claim 31, wherein the coreless roll has a radial compressive strength of 30 N or greater.

34. A coreless roll of a tissue paper product, the coreless roll being made of a continuous web of tissue paper product helically wound with a first end and a second end, the web of tissue paper product being wound to define an axially extending inner hole centrally positioned relative to the coreless roll, such that the first end is located outside the coreless roll and the second end is located at the inner hole. The cotton paper product comprises at least two layers, wherein the total number of layers in the cotton paper product is two or three, all layers are conventional wet-pressed (CWP) layers, and wherein at least one of the layers is an embossed layer. The layers of the aforementioned tissue paper product are bonded together. The tissue paper product has a geometric mean tensile strength of at least 200 N / m. The basis weight of the tissue paper product is 35g / m³. 2 Up to 75g / m 2 Within the range, The layers have been embossed into nested patterns. The outer diameter of the coreless roll is in the range of 95 to 150 mm, the diameter of the inner hole is in the range of 20 to 50 mm, and the density of the coreless roll is in the range of 65 to 125 kg / m³. 3 Within the range, and in, If the total number of layers is 2, the caliper measurement ratio of the roll is in the range of 40%-70%; if the total number of layers is 3, the caliper measurement ratio of the roll is in the range of 10%-45%. The caliper measurement ratio (c) s -c t ) / c t It is determined by measuring the standard caliper value c of the tissue paper product as defined by standard ISO-12625-3:2014. s The theoretical caliper value c of the cotton paper product t The difference between them divided by the theoretical caliper measurement value c t And what was obtained, The theoretical caliper measurement value c t Defined as the ratio between the basis weight of the tissue paper product and the density of the roll. The coreless roll has a radial compressive strength of 20N or greater.

35. The coreless roll of the tissue paper product according to claim 34, wherein the tissue paper product is a household towel.

36. The coreless roll of the tissue paper product according to claim 34, wherein the layers of the tissue paper product are bonded together by adhesives and / or mechanical bonding.

37. The coreless roll of the tissue paper product according to claim 36, wherein the adhesive is a laminating adhesive and the mechanical bonding is edge embossing.

38. The coreless roll of the tissue paper product according to claim 34, wherein the coreless roll has a radial compressive strength of 25 N or greater.

39. The coreless roll of the tissue paper product according to claim 34, wherein the coreless roll has a radial compressive strength of 30 N or greater.

40. The coreless roll of the tissue paper product according to claim 34, wherein at least a portion of the innermost coil of the absorbent material at the second end of the coreless roll comprises a stabilizing coating composition.

41. The coreless roll of the tissue paper product according to claim 40, wherein the entire innermost loop of the absorbent material at the second end of the coreless roll comprises a stabilizing coating composition.

42. A method for manufacturing a coreless roll of tissue paper product, said tissue paper product being made of two layers, said method comprising the following steps: - Provides a first layer of conventional wet-pressed paper (CWP) and a second layer of conventional wet-pressed paper (CWP); - Embossing is applied to the two layers so that they are nested, and the layers are combined to form a weight of 35 g / m². 2 Up to 55g / m 2 The following are cotton paper products with a geometric mean tensile strength of at least 200 N / m and a caliper ratio between 40% and 70%, wherein the caliper ratio (c) is specified in the table. s -c t ) / c t It is determined by measuring the standard caliper value c of the tissue paper product as defined by standard ISO-12625-3:2014. s The theoretical caliper value c of the cotton paper product t The difference between them divided by the theoretical caliper measurement value c t And obtained; - The tissue paper product is spirally wound on a mandrel to form a coreless roll and define an axially extending inner hole, with a first end of the tissue paper product located outside the coreless roll and a second end located at the inner hole; and - Remove the mandrel; The outer diameter of the coreless roll is in the range of 95 to 150 mm, the diameter of the inner hole is in the range of 20 to 50 mm, and the density of the coreless roll is in the range of 70 to 90 kg / m³. 3 Within the range.

43. The method for manufacturing a coreless roll of a tissue paper product according to claim 42, wherein the tissue paper product is a household towel.

44. The method of manufacturing a coreless roll of a tissue paper product according to claim 42, wherein the two layers are bonded together using an adhesive and / or a mechanical bonding method.

45. The method for manufacturing coreless rolls of tissue paper products according to claim 44, wherein the adhesive is a laminating adhesive and the mechanical bonding is edge embossing.

46. ​​The method for manufacturing a coreless roll of cotton paper product according to claim 42, wherein the theoretical caliper value of the formed cotton paper product is at least 0.7 mm.

47. A method for manufacturing a coreless roll of a tissue paper product according to any one of claims 42-46, comprising the step of hot embossing at least one of the two layers.

48. A method for manufacturing a coreless roll of tissue paper product according to any one of claims 42-46, the method comprising the following steps: - The first layer is embossed using a first embossing roller having a first embossing protrusion to form a first embossing having a first height (h1) in the range of 0.2 mm to 2.0 mm; - The second layer is embossed using a second embossing roller with a second embossing protrusion to form a second embossing with a second height (h2) in the range of 0.2 mm to 2.0 mm.

49. The method of manufacturing a coreless roll of a tissue paper product according to claim 48, wherein the tissue paper product further comprises a third layer, the first embossing roller further comprises a third embossing protrusion, and the step of embossing the third layer forms a first and a third embossing on the third layer.

50. The method of manufacturing a coreless roll of a tissue paper product according to claim 48, wherein the method includes the step of embossing the first layer using a third embossing roller having a third embossing protrusion to form a third embossing having a third height (h3) less than the first height (h1) (h1>h3).

51. A method for manufacturing a coreless roll of tissue paper product, said tissue paper product being made of three layers, said method comprising the following steps: - Provides a first layer, a second layer, and a third layer of conventional wet-pressed paper (CWP); - Emboss the three layers so that they are nested, and layer the three layers together to form a weight of 45g / m². 2 Up to 75g / m 2 The following are cotton paper products with a geometric mean tensile strength of at least 250 N / m and a caliper ratio between 10% and 40%, wherein the caliper ratio (c) is specified in the original text. s -c t ) / c t It is determined by measuring the standard caliper value c of the tissue paper product as defined by standard ISO-12625-3:2014. s The theoretical caliper value c of the cotton paper product t The difference between them divided by the theoretical caliper measurement value c t And obtained; - The tissue paper product is spirally wound on a mandrel to form a coreless roll and define an axially extending inner hole, with a first end of the tissue paper product located outside the coreless roll and a second end located at the inner hole; and - Remove the mandrel; The outer diameter of the coreless roll is in the range of 95 to 150 mm, the diameter of the inner hole is in the range of 20 to 50 mm, and the density of the coreless roll is in the range of 65 to 125 kg / m³. 3 Within the range.

52. The method for manufacturing a coreless roll of a tissue paper product according to claim 51, wherein the tissue paper product is a household towel.

53. The method for manufacturing a coreless roll of tissue paper product according to claim 51, wherein the three layers are bonded together by adhesive and / or mechanical bonding.

54. The method for manufacturing coreless rolls of tissue paper products according to claim 53, wherein the adhesive is a laminating adhesive and the mechanical bonding is edge embossing.

55. The method for manufacturing a coreless roll of cotton paper product according to claim 51, wherein the theoretical caliper value of the formed cotton paper product is at least 0.7 mm.

56. A method for manufacturing a coreless roll of tissue paper product according to any one of claims 51-55, the method comprising the following steps: - The first layer is embossed using a first embossing roller having a first embossing protrusion to form a first embossing having a first height (h1) in the range of 0.2 mm to 2.0 mm; - The second layer is embossed using a second embossing roller having a second embossing protrusion to form a second embossing having a second height (h2) in the range of 0.2 mm to 2.0 mm; - Wherein the first layer, the second layer and the third layer are layered together such that the third layer is located between the first layer and the second layer.

57. The method of manufacturing a coreless roll of a tissue paper product according to claim 56, wherein the first embossing roller further includes a third embossing protrusion, and the step of embossing the third layer forms the first and third embossings on the third layer.

58. The method of manufacturing a coreless roll of cotton paper product according to claim 56, wherein the method includes the step of embossing a first layer using a third embossing roller having a third embossing protrusion to form a third embossing having a third height (h3) less than the first height (h1) (h1>h3).

59. The method for manufacturing a coreless roll of tissue paper product according to claim 58, wherein, The first layer and the third layer are embossed together using the first embossing roller to form the first embossing on the first layer and the third layer. The third embossing is formed only on the first layer but not on the third layer, or the first layer and the third layer are embossed together to form the third embossing on the first layer and the third layer.

60. The method for manufacturing coreless rolls of tissue paper products according to claim 59, The first embossing is formed by a first heated embossing roller, and / or The second embossing is formed by a second heated embossing roller, and / or The third embossing is formed by the first heated embossing roller or the third heated embossing roller.

61. The method for manufacturing coreless rolls of tissue paper products according to any one of claims 51-55, The method includes the step of coating at least a portion of the innermost coil at the second end of the coreless roll of the tissue paper product with a stabilizing coating composition.

62. The method of manufacturing a coreless roll of a tissue paper product according to claim 61, wherein the method comprises the step of coating the entire innermost loop of the coreless roll of the tissue paper product at the second end with a stabilizing coating composition.

63. A coreless roll of a tissue paper product manufactured using the method according to any one of claims 42-62.

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