RU2751637C1 - Coreless reel of an absorbent sheet and method for manufacture thereof - Google Patents

Abstract

FIELD: paper.SUBSTANCE: present invention relates to a coreless reel of an absorbent sheet product, a method for manufacture thereof and an application of a coreless reel as toilet paper, domestic towel, hand towel, kitchen towel, wiping paper, cosmetic tissue, handkerchief or sanitary napkin. The coreless reel of an absorbent sheet product is formed from a spirally wound continuous sheet of absorbent material with a first end and a second end. The sheet of absorbent material is wound so as to create an axial hollow opening located in the centre of the relatively coreless reel and extending from one end to the other end of the coreless reel so that the first end is located on the outside of the roll and the second end is located at the axial hollow opening and constitutes no more than 40% of the entire length of the continuous sheet of absorbent material. The second end of the continuous sheet of absorbent material includes a liner composition containing a non-ionic cellulose ether.EFFECT: technical result is creation of a coreless reel of an absorbent product combining excellent rigidity and resistance to flattening with proper peeling force, sufficient flexibility and elasticity, excellent degradability in water and possibility of use along the entire length.24 cl, 11 ex, 2 tbl, 7 dwg

Description

Technology area

The present invention relates to a coreless roll of absorbent sheet as an article such as sanitary napkins, toilet paper, towels, etc. In one aspect of the present invention, the coreless roll is formed in a compressed form. The present invention also relates to a method for making a coreless roll.

State of the art

Products made from absorbent sheets in roll form are widely used in modern society. Rolls of toilet paper, towels such as household (kitchen) towels or hand towels, etc. are in constant demand in the trade.

Homemade absorbent sheet rolls (eg, toilet paper) typically consist of a continuous web of absorbent sheet material that is spirally wound around a pre-fabricated core made of a rigid material such as cardboard or glued paper. The core forms an axial hollow opening that is positioned in the center of the roll and extends from one end of the roll to the other. The axial hollow opening allows the user to easily position the roll on the roll holder shaft. However, the liner is expensive, requires storage space and additional manual handling. In addition, the sleeve remains after use of the absorbent sheet product, thereby increasing the risk of clogging the sewer system.

To solve these problems, “linerless” rolls and rolls with water soluble liners have been developed. The most important properties of these products are their resistance to flattening and their flexibility / resilience.

"Flattening" as used herein refers to the phenomenon that occurs when the first inner turns of the roll (ie, turns forming an axial hollow opening at the start of winding) of an absorbent sheet article cannot be stably held so that the axial hollow opening is well defined. Generally, tubeless rolls are associated with an increased risk of flattening. Flattening usually occurs during the production of coreless rolls, when the temporary core is removed after winding is complete, or during storage and transport of the finished product. Due to the flattening, it becomes difficult to place the roll on the roll holder shaft. In addition, flattening tends to give consumers a feeling of reduced quality.

The "flexible" roll provides the advantage that it can be formed in a compressed form, which requires less space during storage and transport. As a result, storage and transportation costs can be significantly reduced. The roll can be returned from its compressed (oval) shape to its uncompressed (cylindrical) shape by applying pressure along the long diameter of the compressed (oval) shape, that is, perpendicular to the axis of the roll.

However, the absorbent sheet product constituting the first inner turns of the roll must be stably maintained when the roll is returned from a compressed form to an uncompressed form. That is, the axial hollow opening must open independently and be clearly defined when the roll returns to its cylindrical shape. The roll must thus exhibit substantial flexibility and a certain level of elasticity, which implies that the roll can be returned to its cylindrical shape while reopening the axial hollow opening in a well-defined manner. This requires that the first inner turns again and stably maintain the axial hollow opening. As a result, there should be no significant visible difference in appearance between a roll that has returned from a compressed form to an uncompressed form and a roll that has not been compressed.

In addition, the roll can be subjected to deforming forces during manufacture, packaging, storage and transportation, for example, radial forces applied in the unwinding and / or cutting device, axial loads occurring during packaging, and / or when the packaged roll products are stacked. on pallets for storage / shipment, etc. Due to the effect of deforming forces, the continuous web of absorbent material can be irreversibly deformed, thereby giving consumers a feeling of reduced quality. Therefore, the roll must also exhibit a certain level of axial and radial stiffness (sometimes also called "rigidity"), which implies that the roll is less likely to deform and / or damage during manufacture, packaging, etc.

The prior art describes methods of making flexible rolls of an absorbent sheet product that can be formed in a compressed form.

Patent document WO 2009/027874 A1 discloses a roll comprising a web of nonwoven fabric that is spirally wound around a flexible core. The flexible sleeve consists of a plastic sheet of synthetic polymers that is bonded to the inner layer of the nonwoven web by means of a bonding means such as adhesive, heat bonding, etc. The flexible core has a higher machine direction tensile strength than nonwoven fabric. As a result, the roll is flexible for packaging and storage purposes.

However, synthetic resin resin sheet is pre-fabricated, stored and handled by hand. In addition, in industrial production, a continuous web of absorbent material travels at a speed of about 10 m / s. This makes it technically difficult to insert and attach the resin sheet to the core nonwoven layer at travel speeds required for industrial production.

Patent document WO 95/13183 A1 discloses a roll of elongated material having a core at the center of the roll. The sleeve essentially includes several turns of elongated material that are held together by a bonding material such as latex, starch, polyvinyl alcohol, etc. Patent document WO 95/13183 A1 also discloses a method for producing such a compressed roll. More specifically, WO 95/13183 A1 discloses that a binder solution is sprayed on or coated onto the first turns of a conventional winding. Upon completion of winding and removal from the winding shaft, the roll is immediately compressed to an elliptical or oval cross-section. The document describes that the roll can be released from the compressed form by applying pressure to the "shorter" sides of the ellipse.

However, a binder as described in WO 95/13183 A1 (eg latex, starch, polyvinyl alcohol, etc.) creates a rigid sleeve that includes several turns of glued elongated material. Therefore, the resulting sleeve has no flexibility and exhibits low elasticity. As a result, after the coil has been compressed, it is difficult to reopen its axial hollow opening in a way that results in a well-defined axial hollow opening.

In addition, the first inner turns of the elongated material (ie, the turns of the elongated material forming the sleeve) are held adhered to each other by means of a bonding material. The peel force required to separate the first inner turns is generally higher than the tensile strength of the elongated absorbent material. Therefore, it is difficult to separate the first inner turns without breaking the elongated material on which the bonding material is applied. As a result, it is not possible to use an elongated absorbent material along its entire length, that is, up to the last sheet.

Patent document WO 2011/126707 A2 discloses an aqueous paper roll adhesive comprising (A) a saccharide, (B) a viscosity modifier, and (C) a glycol and / or a trihydric alcohol. The adhesive, as indicated in WO 2011/126707 A2, exhibits good initial tack when wet and good peelability when dry. However, the paper to which the adhesive is applied shows some stiffness. As a result, the paper product in roll form has no flexibility, and after the roll has been compressed, it is difficult to reopen the axial hollow opening so as to provide a well-defined axial hollow opening.

It is desirable to provide a coreless roll of absorbent sheet product that combines excellent rigidity (and thus also flattening resistance) with adequate peeling force, but is also sufficiently flexible and elastic.

It is also desirable to provide a roll of absorbent sheet product that can be used over substantially its entire length (i.e., substantially up to the last sheet) and prevents clogging of sewer systems (decomposition time).

It is also desirable to provide a coreless roll of absorbent sheet product in a compressed form in which, after the roll has been compressed, the axial hollow opening can be substantially reopened in a manner resulting in a well-defined axial hollow opening.

It is also desirable to provide a method for making such a coreless roll of absorbent sheet product.

The essence of the invention

The present invention relates to a coreless roll of absorbent sheet product, such as sanitary napkins, toilet paper, towels, etc., formed from a continuous web of absorbent material having a first end and a second end, the continuous web of absorbent material being wound to create an axial hollow opening located in the center of the relatively linerless roll and extending from one end to the other end of the linerless roll, and such that the first end is located on the outside of the roll, and the second end is located at the axial hollow opening;

wherein the second end of the continuous web of absorbent material comprises a cover composition comprising a nonionic cellulose ether.

The present invention also relates to such a coreless roll that is formed in a compressed form.

The present invention also relates to a method for making a coreless roll of an absorbent sheet product, comprising the steps of:

- moving a continuous web of absorbent material having a first end and a second end, which is preferably composed of 1 tissue paper layer, or 2 to 6, in particular 2 to 5 superimposed tissue layers;

- applying a coating composition containing a non-ionic cellulose ether to the second end;

- spirally winding a continuous web of absorbent material so as to form a long roll (log) of a web of absorbent material, the web of absorbent material being wound so as to define an axial hollow opening positioned in the center of the log and extending from one edge of the log to the other edge of the log, and so that the first end is on the outside of the log and the second end is at the axial hollow opening;

- cutting the log into numerous caseless rolls;

- optionally, subjecting the linerless roll to compression in a direction perpendicular to the axial hollow opening to obtain a linerless roll in a compressed form.

In one aspect of the present invention, the nonionic cellulose ether has a number average molecular weight of 1,000 to 1,000,000, preferably 2,000 to 500,000, more preferably 3,000 to 200,000, more preferably 5,000 to 100,000.

In yet another aspect of the present invention, the nonionic cellulose ether is an alkyl cellulose ether such as methyl cellulose or ethyl cellulose. In yet another aspect of the present invention, the nonionic cellulose ether is a hydroxyalkyl cellulose ether such as hydroxyethyl cellulose or hydroxypropyl cellulose.

The coreless roll of the absorbent sheet product of the present invention is excellent in rigidity and flattening resistance, while also being sufficiently flexible and elastic. Moreover, the coreless roll according to the present invention also exhibits excellent water degradability and can be used along its entire length.

The present invention includes the following embodiments (“clauses”):

1. A coreless roll of absorbent sheet product formed from a spirally wound continuous web of absorbent material having a first end and a second end, the continuous web of absorbent material being wound so as to create an axial hollow opening located in the center of the coreless roll and extending from one edge to the other end of the coreless roll, and such that the first end is located on the outside of the roll, and the second end is located at the axial hollow opening;

wherein the second end of the continuous web of absorbent material comprises a cover composition comprising a nonionic cellulose ether.

2. A linerless roll according to claim 1, wherein the linerless roll is obtained by applying a coating composition to the second end of a continuous web of absorbent material.

3. The linerless roll according to claim 1 or 2, wherein the nonionic cellulose ether has a number average molecular weight of 1,000 to 1,000,000, preferably 2,000 to 500,000, more preferably 3,000 to 200,000, more preferably 5,000 to 100,000.

4. The linerless roll according to claim 1 or 2, wherein the nonionic cellulose ether has a viscosity average molecular weight of 5,000 to 2,000,000, preferably 10,000 to 1,500,000, more preferably 30,000 to 1,000,000.

5. The linerless roll according to any one of claims 1 to 4, wherein the nonionic cellulose ether has a water solubility at 25 ° C of at least 40 g / L.

6. The linerless roll according to any one of claims 1-5, wherein the nonionic cellulose ether is an alkyl cellulose ether such as methyl cellulose or ethyl cellulose.

7. The linerless roll according to any one of claims 1-5, wherein the nonionic cellulose ether is a hydroxyalkyl cellulose ether such as hydroxyethyl cellulose or hydroxypropyl cellulose.

8. The linerless roll according to any one of claims 1-5, wherein the nonionic cellulose ether is a combination of an alkyl cellulose ether and a hydroxyalkyl cellulose ether.

9. A linerless roll according to any one of claims 1 to 8, wherein the coating composition comprises:

(a) at least 50 wt%, preferably at least 65 wt%, more preferably at least 80 wt% nonionic cellulose ether;

(b) not more than 50 wt.%, preferably not more than 35 wt.%, more preferably not more than 20 wt.% additional additives such as plasticizers, hardening agents, flavors and colorants;

in each case based on the total solids content of the coating composition.

10. The linerless roll according to any one of claims 1 to 9, wherein the coating composition is applied as an aqueous solution, the aqueous solution preferably containing a non-ionic cellulose ether in an amount of at least 0.1 wt%, more preferably at least 0, 5% by weight, based on the total weight of the aqueous solution.

11. The linerless roll according to any one of claims 1-10, wherein the coating composition does not contain hydroxyl-terminated polyether and / or does not contain saccharides other than nonionic cellulose ether.

12. The linerless roll according to any one of claims 1-11, wherein the axial hollow opening has a circumferential periphery and the coating composition is applied circumferentially and preferably such that the resulting coating occupies at least 50% of the second end, preferably at least 75%, more preferably at least 95% of the second end.

13. The sleeveless roll according to any one of claims 1-12, wherein the coating composition is applied continuously in the machine and axial directions, or intermittently in the machine and / or axial directions.

14. A sleeveless roll according to any one of claims 1 to 13, wherein the second end consists of at least one turn, preferably at least two turns, preferably at least three turns, for example 3 to 50 turns, for example from 3 to 30 turns, or from 4 to 40 turns, preferably from 3 to 30 turns, the turn being formed by one turn of the spirally wound continuous web around an axial hollow opening.

15. The coreless roll according to any one of claims 1-13, wherein the second end comprises at least 5%, preferably at least 10%, more preferably at least 15% of the total length of the continuous web of absorbent material in the machine direction.

16. The coreless roll according to any one of claims 1 to 15, wherein the amount of nonionic cellulose ether is 0.001 to 20 g / roll, preferably 0.005 to 10 g / roll, more preferably 0.005 to 5 g / roll, in particular 0.01 to 2 g / roll.

17. The coreless roll according to any one of claims 1 to 16, wherein the absorbent material web consists of 1 tissue paper layer, or 2 to 6, in particular 2 to 5, superposed tissue layers.

18. The linerless roll according to any one of claims 1-17, in a compressed form.

19. A linerless roll according to any one of claims 1-18, which is an absorbent article selected from the group consisting of sanitary napkins, towels such as household towels, kitchen or hand towels, toilet papers, wiping papers, handkerchiefs , and facial tissues, the absorbent article preferably being toilet paper.

20. A manufacturing method for obtaining a coreless roll of an absorbent sheet product, comprising:

- moving a continuous web of absorbent material having a first end and a second end, which is preferably composed of 1 tissue paper layer, or 2 to 6, in particular 2 to 5 superimposed tissue layers;

optionally cutting the continuous web of absorbent material substantially cross-machine direction to produce single but interlocked sheets;

- applying a coating composition, as defined in any one of items 1-16, onto a continuous web;

- spiral winding of a continuous web of absorbent material so as to form a log of a web of absorbent material, the web of absorbent material being wound so as to define an axial hollow opening positioned in the center of the log and extending from one edge of the log to the other edge of the log, and so that the first the end is on the outside of the log and the second end is at the axial hollow opening; and

- cutting the log into numerous caseless rolls.

21. A manufacturing method according to paragraph 20, further comprising:

- subjecting a linerless roll to compression in the direction perpendicular to the axial hollow opening to obtain a linerless roll in a compressed form.

22. The use of the coreless roll according to any one of items 1-19 as toilet paper, household towel, kitchen towel, hand towel, wiping paper, facial tissue, handkerchief or sanitary napkin.

Where the present description refers to “preferred” embodiments / features, combinations of these “preferred” embodiments / features should also be considered disclosed insofar as this combination of “preferred” embodiments / features is technically significant.

Above and below, in the present specification and in the claims, the use of the term "comprising" is to be understood as a disclosure, as a more limited embodiment, and also as the term "consisting of" insofar as it is technically significant.

Brief Description of Drawings

FIG. 1 is a schematic view showing a perspective view of a coreless roll according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a side view of a coreless roll according to one embodiment of the present invention. The second end, as shown in FIG. 2 has three turns.

FIG. 3 is a schematic diagram of a second end of an unwound continuous web of absorbent material in accordance with one embodiment of the present invention. The gray shading in FIG. 3 shows a coating composition that is continuously applied to the second end.

FIG. 4a and 4b are schematic views of the second end of an unwound continuous web of absorbent material according to one embodiment of the present invention. The gray shading in FIG. 4a and 4b show a coating composition that is periodically applied to the second end in stripes and dots, respectively.

FIG. 1-4b provide an overview of the terminology used in relation to the coreless roll according to the present invention. FIG. 1-4b, the following reference numbers are shown:

(1) coreless roll

(2) spiral wound continuous web of absorbent material

(3) axial hollow opening

(4) edge

(5) first end

(6) second end

(7) coating composition

(8) perforation line

FIG. 5 is a schematic view showing a sectional view of a paper machine (9) illustrating the manufacture of coreless rolls according to one embodiment of the invention. FIG. 5 shows the spray application of a coating composition to a continuous web of absorbent material.

FIG. 6 is a schematic view showing a sectional view of a paper machine (9) illustrating the manufacture of coreless rolls according to one embodiment of the invention. FIG. 6 shows the application of a coating composition to a continuous web of absorbent material using a coating roller.

FIG. 7a, 7b and 7c are schematic diagrams of an apparatus (dynamometer) (39) and a set of rollers (40) - (43) suitable for measuring inter-sheet adhesion (peel force) in a tissue roll (44) according to the present invention. The dimensions in FIG. 7a-7c are given in mm.

Detailed description of the present invention

1. Sleeveless roll

The coreless roll of absorbent sheet product according to the present invention is formed from a spirally wound continuous web of absorbent material having a first end and a second end.

The continuous web of absorbent material is preferably made from base tissue paper, which can be made by Conventional Wet Press or Through Air Drying (TAD) manufacturing processes, or other manufacturing processes. By "base (raw) tissue paper"("tissue paper web"), the inventors of the present invention mean a single ply tissue base paper as obtained from a tissue machine. The base tissue paper has a low basis weight, in the range of 8 to 60 g / m ² , preferably 10 to 30 g / m ² .

The term "layer", as used herein, means one or more plies of tissue paper in the final tissue article (e.g., toilet paper) when it / they are obtained after processing ("processing") one or more webs of the base sanitary paper.

Given the fundamental compatibility of the production methods (wet forming), the manufacture of "tissue paper" is considered to be a papermaking technology. The manufacture of tissue paper differs from papermaking in its exceptionally low basis weight and much higher tensile energy absorption.

Tensile energy absorption is derived from tensile energy absorption, in which the tensile energy absorption is related to the volume of the test specimen before examination (length, width, thickness of the specimen between the clamps before applying the tensile load). Paper and tissue paper also differ, as a rule, with respect to the modulus of elasticity, which characterizes the deformation and strength properties of these planar products as parameters of the material.

The high tensile energy absorption of tissue paper is due to external or internal creping. The former is obtained by compressing a paper web adhered to a dry cylinder by a creping doctor or, in the latter example, by a difference in speed between two meshes ("fabrics"). This causes internal fracture of the plastically deformable, still wet paper web due to compressive and shear forces, thereby making it more tensile under load than uncreped paper. High tensile energy absorption can also be achieved by imparting a three-dimensional (3D) structure to tissue paper using the wire mesh itself. Most of the functional properties typical of tissue paper and tissue products are due to their high tensile energy absorption (see standards DIN EN 12625-4 and DIN EN 12625-5).

Typical properties of tissue paper include the ability to easily absorb tensile energy, its drape, good flexibility like a textile material, properties often referred to as bulk softness, high surface softness, high specific volume with sensible thickness, and high liquid absorption capacity. and, depending on the application, adequate wet and dry strength as well as an interesting visual appearance of the outer surface of the product. These properties allow the use of tissue paper such as wiping rags (such as household towels), hygiene products (such as toilet paper, hand towels) and napkins (such as cosmetic wipes, handkerchiefs) ...

According to one embodiment of the present invention, the continuous web of absorbent material preferably consists of 1 tissue tissue layer, or 2 to 5 superimposed tissue tissue layers.

Sanitary paper can be made from fibers for papermaking according to "Standard Methods" such as for making "Dry Crepe Tissue" or "Wet Crepe Tissue" creping) or Processes for Structured Tissue such as Through Air Drying (TAD) air (UCTAD), or alternative manufacturing methods such as Voith's Advanced Tissue Molding System (ATMOS), or Energy Efficient Technologically Advanced Drying eTAD (eTAD) Georgia Pacific, or Structured Tissue Technology SST hygienic paper ") by Metso Paper. Hybrid methods such as NTT (New textured Tissue), which are modifications of traditional methods, can also be used.

The traditional dry creping method includes:

- pressing and drying the wet paper fibers to form a sheet on a heated large diameter cylinder (also called Yankee cylinder); and

- then separating and creping the sheet of dried paper fibers using a metal scraper coupled to the specified cylinder across the direction of its rotation.

The creping operation creates undulating irregularities in the sheet across the direction of its movement. The creping operation increases the thickness of the sheet and gives elasticity and gives the sheet tactile properties (soft to the touch).

The TAD manufacturing method includes:

- forming a sheet of wet paper fibers on a cloth tape; and

- then drying the sheet, at least in part, by means of a stream of hot air passed through it.

The dried sheet can then be creped.

In addition, a method as described in WO 2016/173641 A1 (title: Sanitary paper comprising cellulose fibers, derived from miscanthus, and the method of its manufacture ", incorporated herein by reference). More specifically, reference is made to the description of claim 3 on pages 22-27 of this application and the details of the TAD method disclosed therein (eg, three-dimensional (3D) web shape, permeable drying cylinder, etc.). The parameters described in this text passage are also suitable for use in ATMOS technology.

Once the tissue paper has been made, a separate process step called a recycling step is usually used to form a tissue paper product (i.e., paper towels, rolls of toilet paper, bathroom tissue paper, tissue paper for wipes, kitchen tissue rolls, handkerchiefs, etc.).

In one further embodiment of the continuous web of absorbent material, the absorbent material is a "nonwoven material". The term “nonwoven fabric” is widespread in the art and can be further defined as described in ISO 9092: 2011, also for the purpose of the present invention. Typical methods of making nonwovens include airlaid technology, spunbond technology, dry lay technology, and long fiber wet lay technology. The web of nonwoven fabric used in this embodiment can be a single layer or a multi-layer web.

According to one preferred aspect of this embodiment, the absorbent nonwoven web used in the coreless roll of the invention comprises cellulosic fibers. In this case, the content of cellulosic fibers, based on the total weight of all fibers present in the nonwoven web, is at least 20 wt%, more preferably at least 50 wt%, for example at least 80 wt%. The rest of the fibers in these cases are non-cellulosic fibers such as synthetic fibers.

The aforementioned pulp fibers (which may also be referred to as "cellulosic fibers") can be obtained from virgin and / or recycled pulp and paper raw materials. Cellulosic fibers that can be used in the invention usually contain, as the main structure-forming component, a proportion of long-chain fibrous cellulose that is present in natural cellulose-containing cells, in particular in tree cells. The fibers are preferably recovered from tree plants by treatment in cooking steps to remove or reduce lignin and other extractable components, and optionally in bleaching steps. Cellulosic fibers can also come from non-woody sources such as annuals.

Suitable cellulose fibers that can be used can be of the regenerated type (eg Lyocell), although other types of cellulose are preferred. The celluloses used can be primary fibrous material ("primary fibers") or recycled fibrous material (recycled celluloses). The cellulose may come from non-lignin or low lignin sources such as cotton wool, esparto (alpha) grass, pomace (such as cereal straw, rice straw, bamboo or hemp), hemp fibers, miscanthus grass fibers, or flax (also called "non-wood fibers" in the description and in the claims). Preferably, the cellulose is obtained from a lignocellulosic material such as softwood (which usually comes from softwood) or hardwood (usually from deciduous trees).

It is possible to use "chemically treated cellulose" or "mechanically treated cellulose", and therefore it is preferable to use chemically treated celluloses.

"Chemical processed celluloses" as used herein according to DIN 6730 are fibrous materials obtained from vegetable raw materials, from which most of the non-cellulosic components have been removed by chemical cooking without significant mechanical additional processing. "Mechanically processed cellulose" as used herein is a generic term for a fibrous material made entirely or almost entirely from wood by mechanical means, optionally at elevated temperatures. Mechanically processed pulps can be categorized into purely mechanical pulps (wood pulp and refined mechanical pulps) as well as chemically pretreated mechanical pulps such as chemo-mechanical pulps (CMP) or chemo-thermomechanical pulps (CTMP).

In the present invention, with reference to FIG. 1 and 2, a continuous web (2) of absorbent material is spirally wound so as to form an axial hollow opening (3) centered on the roll (1) and which extends from one end (4) to the other end (4) of the roll ... As used herein, "axial hollow opening" means a tubular opening that extends through the roll along its central axis. The axial hollow opening allows the end user to mount the roll onto the roll holder shaft. When the roll is placed on the roll holder shaft, the absorbent material is dispensed from the first end (outside the roll) while the roll is free to rotate about its central axis. The axial hollow opening has a diameter of 10 mm to 70 mm, preferably 20 mm to 50 mm.

In the present invention, the axial hollow opening (3) is extending from one edge (4) to the other edge (4) of the coreless roll. The coreless roll of the present invention has a cylindrical circumferential surface and opposing flat ends (ie, edges) that are formed when the roll log is cut into multiple rolls at the end of the winding process. As used here, "edge" means a flat area that is on one side of the roll perpendicular to its central axis.

In the present invention, the continuous web (2) of absorbent material has a first end (5) and a second end (6). The first end (5) is on the outside of the roll and the second end (6) is at the axial hollow opening. Therefore, the continuous web of absorbent material consists, in the machine direction, of a first end and a second end, and a middle portion located between these ends. The combined lengths of the first end, second end, and middle portion define the entire length of the continuous web of absorbent material that forms one roll. In the coreless roll of the present invention, the continuous web of absorbent material includes the cover composition provided herein. A continuous web of a tape of absorbent material is preferably obtained by applying a coating composition to the second end. This results in a continuous web of tape of absorbent material in which the remaining portions, that is, the first end and the middle portion, are preferably substantially or completely free of the cover composition. The resulting continuous web of a tape of absorbent material may thus be different from known continuous webs of absorbent material, for example, a toilet paper treated with a liquid cosmetic, in which the same coating composition (for example, a lotion) is applied to the entire continuous web.

However, this does not exclude that the cover composition in the sense of the invention is applied to the second end of the continuous web of absorbent material, while in addition, the lotion (which is necessarily different from the cover composition) is applied to one side of the entire continuous web of absorbent material.

Additional embodiments of the coreless roll also utilize the concept of the present invention with respect to a continuous web of absorbent material obtained by applying a coating composition to its second end, according to which a portion of the remaining regions, i.e., the first end and the middle region, is preferably less than 20%, more preferably less than 10 %, more preferably less than 5% of the total area of the remaining regions, also contains the same coating composition as applied to the second end.

In one embodiment, the second end (6) consists of at least one turn, preferably at least two turns, more preferably at least three turns, for example three to fifty turns, for example three to thirty turns, or four to forty turns, preferably three to thirty turns, or ten to forty turns. As used herein, "turn" means one revolution of a spirally wound continuous web around an axial hollow opening. For example, FIG. 2 shows three turns at the second end (6) of the web.

In a further embodiment, the second end (6) comprises at least 5%, more preferably at least 10%, more preferably at least 15% of the total length of the continuous web of absorbent material in the machine direction, m preferably not more than 40%, more preferably not more than 35% of the total length of the continuous web of absorbent material in the machine direction.

In one embodiment, the coreless roll of the present invention is formed in a compressed form. As used herein, "compressed shape" means a shape in which the cross section of the roll is oval. When the roll is compressed, the axial hollow opening takes on an oval shape with a narrow, usually oval slot, and the roll holder shaft can no longer be inserted into it. As a result, less space is required for the roll and storage and shipping costs can be reduced. The coreless roll of the present invention can be returned from a compressed (oval) to an uncompressed (cylindrical) form by applying pressure along the longer side (diameter) of the oval roll, that is, perpendicular to the axis of the roll.

2. Covering composition

In the present invention, a nonionic cellulose ether-containing coating composition is applied to the second end of a continuous web of absorbent material. Nonionic cellulose ether is described in more detail in section 2.1 below.

The cover composition can be applied to a continuous web of absorbent material as an aqueous solution. This means that water is added to the coating composition and used as a solvent for the nonionic cellulose ether and additional additives, if present. The aqueous solution of the coating composition preferably contains nonionic cellulose ether in a total amount of at least 0.1 wt%, preferably at least 0.5 wt%, more preferably at least 1 wt%, based on the total weight of the aqueous solution. Additional additives may also be present such as plasticizers, hardening agents, fragrances, colorants, etc. In this case, too, the preferred levels of content explained above in connection with component (b) can be used (but with reference to the total dry matter content of the aqueous solution).

Water is preferably present in an amount that is more than 50 wt%, and more preferably in an amount of more than 65 wt%, more preferably more than 80 wt%, based on the total weight of the aqueous solution.

This aqueous solution of the coating composition can be applied as is, preferably at room temperature, to the second end, for example by spraying, roller coating, or any other suitable application method known in the art. After application of the aqueous solution, the continuous web of absorbent material can be dried, for example, by prolonged storage at ambient conditions, or by other methods known in the art.

In one embodiment, a coating composition useful in the present invention comprises:

(a) at least 50 wt% of said nonionic cellulose ether, preferably at least 65 wt%, more preferably at least 80 wt%, more preferably at least 85 wt%, more preferably at least 90 wt%, more preferably at least 95 wt%;

(b) no more than 50 wt%, preferably no more than 35 wt%, preferably no more than 20 wt%, more preferably no more than 15 wt%, more preferably no more than 10 wt%, more preferably no more than 5 wt% .%, additional additives such as plasticizers, hardening agents, fragrances, dyes, etc .;

in each case based on the total weight (total solids content) of the coating composition.

In one additional embodiment, the coating composition consists of these ingredients in the indicated amounts. In one further preferred embodiment, the coating composition consists of a nonionic cellulose ether.

In one preferred embodiment, the coating composition of the present invention is free of hydroxyl-terminated polyether and / or is free of saccharides other than nonionic cellulose ether. The term "saccharide" is to be understood broadly and includes monosaccharides, disaccharides, oligosaccharides (of at least 3 saccharide units) and polysaccharides such as starch, as well as saccharide-based polymers other than non-ionic cellulose ether, for example, carboxymethyl cellulose (CMC).

In the present invention, the coating composition is applied to at least one of two sides of the continuous web, that is, the top and / or bottom side of the longitudinally continuous web. By "top" side, the inventors of the present invention mean the side of the continuous web that faces outwardly relative to the roll when the web is spirally wound. In one preferred embodiment, the coating composition is applied to the underside, that is, the side facing the axial hollow opening.

The coating composition is preferably applied to the continuous web before it is spirally wound to form a roll. As a result of winding, the coating composition is applied in a circumferential direction relative to the axial hollow opening. In the present invention, the coating composition is preferably applied to the web such that, with respect to the total area of the second end (i.e., the area containing the resulting coating), at least 50%, preferably at least 75%, and especially at least 95 %.

If the coating is applied to the second end of the web intermittently in the machine and / or axial direction, for example, relative to individual revolutions of the web around the axial hollow opening, i.e. if one or more revolutions are not completely covered when viewed from the edges of the roll, then it is also preferred that the area containing the resulting coating constituted at least 50% of the total covered area, preferably at least 75%, and in particular at least 95% of the total area of the second end.

In the present invention, a coating composition can be applied to the second end of the continuous web to create a solid or partial coating. As used herein, "continuous coating" means a coating that is applied continuously in the machine direction and axial (transverse) direction, that is, the second end of the web does not include any uncoated areas (eg, see Fig. 3).

As used herein, "partial coating" means that a coating composition is applied to a continuous web such that it partially covers the surface of the web (ie, its second end). Partial coating is formed, for example, if the coating is applied to the second end of the web intermittently in the machine and / or axial direction. There is no particular limitation with respect to the predefined coating pattern. Partial coverage can form cohesive (for example, stripes, lines, or waves) or discrete deposits (for example, points, squares, circles, or any other geometric shape).

In one embodiment of the partial coating, the coating is applied intermittently in the machine and / or axial direction, for example

- continuously in the machine direction, but periodically in the axial (transverse) direction, for example, in the form of one or many parallel strips running in the machine direction (for example, see Fig.4a),

- continuously in the axial (transverse) direction, but periodically in the machine direction, for example, in the form of one or many parallel stripes running in the axial direction, that is, from one end of the roll to the other end,

- periodically in the machine and axial (transverse) direction, for example, in the form of parallel stripes crossing each other.

In one embodiment of the partial coating, the coating is applied intermittently in the form of dots, as shown in FIG. 4b. The dots can form a regular or irregular pattern as a result of, for example, spraying or roller coating.

In one embodiment, the coating composition is applied intermittently such that it covers at least 35% of the surface of the second end, preferably at least 50% of the surface of the second end, and more preferably at least 75%, such as at least 95% of the total surface second end.

2.1. Non-ionic cellulose ether

In embodiments of the present invention, the coating composition comprises a nonionic cellulose ether to achieve the desired technical effects.

According to the present invention, preferably used cellulose ethers can be described as follows. Cellulose ethers are polymers derived from cellulose that are obtained by replacing (in whole or in part) the hydroxyl groups of cellulose. The use of a single esterifying agent (alkylating agent) in the displacement process results in a single cellulose ether, while the use of different types of reactants results in mixed cellulose ethers (mixed ethers). The level of substitution is described as the degree of substitution (DS), defined as the average number of hydroxyl groups substituted per anhydroglucose unit. The DS value can vary between> 0 and 3. If an esterifying (alkylating) reagent such as an alkylene oxide esterifying reagent is used, a new hydroxyl group can be formed and can further react to form oligomeric chains. In this case, the degree of substitution is described as molar substitution (MS), defined as the average number of moles of the esterifying reagent per mole of anhydroglucose unit.

The degree of substitution (DS) and molar substitution (MS) of (ionic or non-ionic) cellulose ethers can be determined by methods known in the art, for example, ¹³ C-NMR spectroscopy or Zeisel-GC, as described by the authors. Hodges et al. In Anal. Chem., 1979, Volume 51 (No. 13), pp. 2172-2176.

Cellulose ethers fall into two categories, namely ionic cellulose ethers and nonionic cellulose ethers. Ionic cellulose ethers such as sodium carboxymethyl cellulose (CMC) contain substituents that are electrically charged, while non-ionic cellulose ethers such as methyl cellulose, hydroxypropyl cellulose, etc. contain electrically neutral substituents. The cellulose ethers used in the present invention are of the non-ionic type.

Without wishing to be bound by any theory, it is believed that nonionic cellulose ethers provide a finely tuned degree of adhesion between the coating composition and the elongated absorbent material. As a result, excellent rigidity and flattening resistance can be achieved, as well as sufficient flexibility and elasticity. In addition, the peel force can be kept within an acceptable range, and thus the elongated absorbent material can be used along its entire length, that is, up to the last sheet. On the other hand, ionic cellulose ethers such as CMC can adhere strongly to the absorbent material if used in larger quantities, so that the peel force required to separate the first inner coils can become higher than the tensile strength of the elongated absorbent material. material. As a result, it can become difficult to separate the first inner loops without breaking the elongated absorbent material.

As used herein, the term "nonionic cellulose ether" is to be understood broadly and includes all types of cellulose ethers - for example, alkyl cellulose ethers, hydroxyalkyl cellulose ethers, alkyl hydroxyalkyl cellulose ethers, and mixed ethers thereof - provided that they are non-ionic.

In one embodiment, the nonionic cellulose ether has a number average molecular weight of 1,000 to 2,000,000, such as 1,000 to 1,000,000, preferably 2,000 to 800,000, such as 2,000 to 500,000, more preferably 3,000 to 200,000, more preferably 5,000 to 100,000 The number average molecular weight of the nonionic cellulose ether used in the present invention can be determined by methods known in the art such as gel permeation chromatography (GPC).

In one embodiment, the nonionic cellulose ether has a viscosity average molecular weight of 5,000 to 2,000,000, preferably 10,000 to 1,500,000, more preferably 30,000 to 1,000,000. The viscosity average molecular weight of the nonionic cellulose ether used in the present invention can be determined by methods known in the art. such as viscometry.

In one additional embodiment, the nonionic cellulose ether is an alkyl cellulose ether such as methyl cellulose or ethyl cellulose. As used herein, an "alkyl cellulose ether" is to be understood as a (non-ionic) cellulose ether in which some of the hydroxyl groups of the cellulose (at least one hydroxyl group in one individual anhydroglucose unit) are substituted with an alkyl group, i.e., linear or branched an alkyl group having from 1 to 20 carbon atoms, preferably from 1 to 12 carbon atoms, more preferably from 1 to 6 carbon atoms, in particular a methyl group, an ethyl group or a propyl group. In addition, the expression "alkyl cellulose ether" in accordance with the present invention is intended to include cellulose ethers such as methyl cellulose or ethyl cellulose, as well as mixed ethers thereof such as hydroxyalkyl methyl celluloses, for example hydroxyethyl methyl cellulose.

In one preferred embodiment, the nonionic cellulose ether is an alkyl cellulose ether selected from methyl cellulose (MC), mixed MC ethers such as hydroxyethyl methyl cellulose (HEMC), hydroxypropyl methyl cellulose (HPMC) and hydroxybutyl methyl cellulose (HBMC), ethyl cellulose (EC), mixed ethers EC such as hydroxyethylethylcellulose (HEEC), hydroxypropylethylcellulose (HPEC) and hydroxybutylethylcellulose (HBEC). The cellulose ether is preferably MC, EC, or HPMC, more preferably MC or EC.

MC, as preferably used herein, may have a DS of 1.4 to 2.4, preferably 1.6 to 2.0. HEMC, as preferably used herein, can have (methyl) DS from 1.3 to 2.2, and (hydroxyalkyl) MS from 0.06 to 0.5. HPMC, as preferably used herein, may have a DS of 1.1 to 2.0 and an MS of 0.1 to 1.0. HBMC, as preferably used herein, typically has a DS greater than 1.9 and not greater than 2.4, and an MS greater than 0.04 and not greater than 0.6. EC, as preferably used herein, may have (ethyl) DS from 1.0 to 2.5, preferably DS from 1.1 to 1.5.

In another preferred embodiment, the nonionic cellulose ether is a hydroxyalkyl cellulose ether such as hydroxyethyl cellulose or hydroxypropyl cellulose. As used herein, "hydroxyalkyl cellulose ether" means a (non-ionic) cellulose ether in which some of the hydroxyl groups of the cellulose are replaced by a hydroxyalkyl group, for example, a linear or branched hydroxyalkyl group having from 1 to 20 carbon atoms, preferably from 1 to 12 atoms carbon, more preferably 1 to 6 carbon atoms such as a (2-hydroxy) propyl group or a hydroxyethyl group.

In one preferred embodiment, the nonionic cellulose ether is an ether of hydroxyalkyl cellulose selected from hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), and hydroxybutyl cellulose (HBC). The hydroxyalkyl cellulose ether is preferably HEC or HPC, more preferably HPC. HEC as used herein can have an MS of 0.1 to 3.6, preferably 1.5 to 3.5. HPC as used herein can have an MS of 1.0 to 3.8, preferably 2.0 to 3.6.

The definition of "nonionic cellulose ether" as used herein also includes a mixture (combination) of at least two, for example 2, 3 or 4, different nonionic cellulose ethers, in particular a mixture of an alkyl cellulose ether and a hydroxyalkyl cellulose ether such as a mixture of MC and HPC.

In one preferred embodiment, the nonionic cellulose ether exhibits a water solubility at 25 ° C. of at least 40 g / l, preferably 200 g / l, in particular 500 g / l. The solubility of the nonionic cellulose ether in water ensures that the absorbent sheet product of the present invention (in particular, toilet paper, etc.) has good toilet flushing and biodegradability. Due to the relatively high solubility of the nonionic cellulose ether, it dissolves on contact with water in the sewer system, or at least rapidly forms a dispersion. As a result, clogging of the sewer systems can be effectively prevented. For other versions of the sleeveless roll, which are usually not disposed of through sewers, such as sanitary napkins, towels, for example, household towels, tea towels or hand towels, toilet papers, wiping rags and handkerchiefs, this feature is not required, but is preferred.

In the present invention, the amount of nonionic cellulose ether in the coating composition is adjusted such that the nonionic cellulose ether is applied to the second end in a total amount of 0.001 to 20 g / roll, preferably 0.005 to 10 g / roll, more preferably 0.005 to 5 g. / roll, more preferably 0.01 to 2 g / roll. When the amount of nonionic cellulose ether applied to the second end is less than 0.001 g / roll, the desired properties in terms of stiffness and flattening resistance cannot be fully achieved. In contrast, when the amount of nonionic cellulose ether applied to the second end is over 20 g / roll, the roll exhibits high rigidity and resistance to flattening, but manufacturing costs may become high.

2.2. Additives

Plasticizer

The coating composition according to the present invention may include a plasticizer, for example, a known ester-type plasticizer. The plasticizer can improve the film-forming properties of the coating composition. It is selected to be compatible with the above described nonionic cellulose ether. In one embodiment, the coating composition of the present invention does not contain a plasticizer.

One type of plasticizer by itself can be used, or two or more types can be used in combination.

For reasons of stability over time, the content of plasticizer in the coating composition according to the present invention is preferably at most 20 wt% of the total solids content, more preferably at most 10 wt%, even more preferably at most 5 wt%.

Hardening agent

The coating composition according to the present invention may include a toughening agent.

In one embodiment, the coating composition according to the present invention does not contain hardening chemical additives such as stable resins, for example, free of the water-soluble cationic or anionic polymers described below.

Other additives

The composition may contain known additives of various suitable types as long as this does not interfere with the manifestation of the effects of the present invention. Examples include perfume, colorant, surfactant, decalcifier, and antibacterial agent, as well as inorganic or organic fillers.

One type can be used alone, or two or more types can be used in combination.

3. Absorbent article

The coreless roll according to the present invention has many applications in the field of sanitary and hygienic or household absorbent articles. In particular, the roll of the present invention may be an absorbent sheet product selected from the group consisting of sanitary napkins, towels such as tea or hand towels, toilet paper, wiping papers, and facial tissues.

In the present invention, the absorbent sheet product is in the form of a continuous web of absorbent material having a first end and a second end, which consists of at least one layer of tissue paper base with a typical basis weight of 8 to 60 g / m ² , preferably 10 up to 30 g / m ² .

In one embodiment, the continuous web of absorbent material is a single layer tissue made from tissue paper or a multi-layer sheet formed from, for example, 2-5 layers of tissue paper overlaid on top of each other. To obtain a multilayer absorbent sheet product, single-layer base tissue papers are combined in a processing step to a final number of layers, which may be, for example, from 2 to 5, depending on the desired properties of the final product. The total basis weight of the resulting multi-layer web is preferably no more than 120 g / m ² , and more preferably less than 100 g / m ² , for example, less than 90 g / m ² .

In the present invention, the second end of the continuous web is coated with a coating composition of the present invention (i.e., a composition comprising a nonionic cellulose ether as described above) and is spirally wound to form a roll of absorbent sheet product such as a roll of toilet paper. The coating composition can be applied to the second end using methods known in the art. These common methods include "spraying" and "roller coating".

In the present invention, the coating composition is applied to at least one of two sides of the continuous web, that is, the top and / or bottom side of the longitudinally continuous web, or between the web-forming layers of tissue base paper.

When the web is a multi-layer web, for example a web having 2 to 5 layers of tissue paper superimposed on one another, the coating composition can be applied to one or both sides of one or more layers, for example all layers. In one embodiment, the coating composition is applied to one of the outer layers of the web, preferably to the outer layer, which faces the axial hollow opening of the finished absorbent sheet product (i.e., the outer layer, which is the layer closest to the axial hollow opening). The outer layer can be coated on one or both sides, preferably on its lower side, that is, on the side facing the axial hollow opening.

The absorbent sheet product according to the present invention is preferably selected from sanitary napkins, towels such as kitchen or hand towels, toilet paper, wiping papers, and facial tissues. As used here, "toilet paper" means a soft and strong tissue base paper that is used to clean the buttocks after using the toilet (sometimes also called "paper towel").

The present invention also relates to the use of the coreless roll as toilet paper, household towel, tea towel, wiping paper, napkin or handkerchief.

According to one preferred embodiment, the absorbent sheet product is a toilet paper consisting of 2-5 layers of tissue paper overlapping each other, for example 2 to 4 layers of tissue paper, in which the coating composition is applied to at least one outer layer of a continuous web, preferably on the underside of the outer layer closest to the axial hollow opening.

The dimensions of the coreless roll according to the present invention are not limited, and are highly dependent on the target absorbent sheet product. For example, an individual roll can have a diameter (edge diameter) of 5 cm to 50 cm, preferably 8 cm to 20 cm. The axial hollow opening can have a diameter of 10 mm to 70 mm, preferably 20 to 50 mm. The width of the roll (i.e., the distance between one edge and another edge) can be in the range from 60 mm to 800 mm, preferably from 70 mm to 400 mm, for example, from 80 mm to 150 mm.

The continuous web of absorbent material forming the absorbent sheet product preferably has an overall MD length of 1 m to 60 m, preferably 1.5 m to 50 m, such as 2 m to 40 m. Optionally, the web may be partially cut in the machine direction so that it consists of successive single but linked sheets. A single sheet can have a length (in the machine direction) from 80 mm to 300 mm, for example from 100 mm to 250 mm, in particular from 100 mm to 200 mm.

4. A method of manufacturing sleeveless rolls and absorbent products

The present invention also relates to a method for making a coreless roll as described above and below, the method comprising:

(A) moving a continuous web of absorbent material having a first end and a second end, which is preferably constituted by a single tissue paper layer, or 2 to 5 superimposed tissue tissue layers;

(B) applying a coating composition to the second end;

(C) spirally winding a continuous web of absorbent material so as to form a log of the absorbent material web, the absorbent material web being wound to define an axial hollow opening positioned in the center of the log and extending from one edge of the log to the other edge of the log, and so, that the first end is on the outside of the log and the second end is at the axial hollow opening;

(D) optionally cutting the continuous web of absorbent material substantially cross-machine direction to provide single but interlocked sheets;

(E) cutting the log into multiple caseless rolls.

According to one embodiment of the present invention, the above method for making a coreless roll further comprises:

(F) subjecting the linerless roll to compression in a direction perpendicular to the axial hollow opening to obtain a linerless roll in a compressed form.

The coreless roll of the present invention can be made using a commercially available paper converting machine. A suitable paper converting machine can be purchased, for example, from Paper Converting Machine Company (PCMC), Europe.

The description of the method below with reference to the modules / sections of the machine is to be understood as illustrating a machine suitable for making a roll according to the present invention. It is also possible to use machines / sections of other types known in the art.

In the present invention, with reference to FIG. 5 and 6, a method for manufacturing a coreless roll includes the steps:

(A) moving a continuous web (19) of absorbent material having a first end and a second end.

The continuous web (19) of absorbent material used in the present invention is composed of one or more layers of tissue base paper having a basis weight of 8 to 60 g / m ² , preferably 10 to 30 g / m ² . Base tissue paper is typically produced in large original rolls (15) and (16) machine winding for subsequent rewinding and cutting, having a width of 1.80 m to 7 m, as obtained from a tissue machine. The original rolls (15) and (16) of the machine winding are installed on the unwinding stacks (10) and (11) of the paper processing machine (9). The number of machine wound initial rolls used corresponds to the number of layers in the target absorbent sheet product. In FIG. 5 and 6, two original machine-wound rolls (15) and (16), each of which feeds one layer of paper towel (18A) and (18B), are used to obtain a roll (1) of two-layer toilet paper. In some aspects, the original roll (s) can (s) create multi-layer, for example, 2 or more layers, toilet paper (for example, in the case of a production line with insufficient unwinding devices).

Layers (18A) and (18B) are fed from unwinding jigs (10) and (11) to an embossing section (12) in which the layers are superimposed and combined (bonded) to form a continuous web (19) of absorbent material.

The embossing section includes an engraved cylinder (20) and a mating rubber cylinder (21), both rotating in opposite directions, and optionally an adhesive dispenser (not shown). The engraved cylinder can be engraved with a micro-structural pattern that combines a variety of embossed points. The engraved cylinder can emboss one or two levels in overlapping layers.

The glue dispenser, if present, typically includes a bath (glue reservoir), an applicator barrel, and an immersion cylinder. The cylinder of the applicator presses the superimposed layers of tissue paper against the engraved cylinder. A dip cylinder (not shown) picks up the adhesive in the bath and transfers the adhesive to an applicator barrel (not shown). The applicator cylinder is designed to apply a certain pressure to the engraved cylinder on the peripheral region of the embossing projections. At this specified pressure, the adhesive passes through the web and bonds the layers. The amount of adhesive used to bond the layers is preferably 0.1 g / m ² to 5.0 g / m ² , preferably 0.2 g / m ² to 1.0 g / m ² . An example of a suitable adhesive for bonding layers is Swift®tak 1004 from HB Fuller, Europe.

The above-described embossing step is used to combine layers of tissue base paper, and also to emboss or micro-emboss at least one of the layers to create aesthetic effects or modify the thickness, softness, or pliability of the resulting continuous web (19).

(B) Applying a coating composition to the second end of the continuous web so as to form a solid or partial coating. The coating composition is applied to the second end by methods known in the art. In the present invention, among other methods, it is possible to use spraying or roller coating.

As used herein, "spray" means that the coating composition is applied to a continuous web in the form of a dispersion of fine liquid droplets in a gas (ie, spray). Sprays are usually formed using a spray nozzle (spray gun) that has a fluid channel that is operated by mechanical forces that spray the fluid. Liquid droplets can have a size of 1 micron to 1000 microns, for example, from 10 microns to 400 microns.

The paper converting machine (9) can be equipped with one or many spray guns (23A), for example, from 1 to 8 spray guns, which can be placed in any position of the processing line, as far as is rational from the point of view of the desired results (coating on the second end). The spray (s) (23A) may (s) be placed (s) in front of the embossing section (12) so that the coating composition (22) is applied, for example, to the outer layer or between the layers. The atomizer (s) (23A) is preferably positioned between the cutting module (27) and the winding module (28) so that the coating composition (22) is applied to the underside of the outer layer (as shown in FIG. 5)

The spray system includes one or more spray guns (23A), a bath (24), and conduits (25) feeding the coating composition (22) from the bath to the spray gun (s) (23A). The spray system is optionally equipped with a heating system (e.g., a heating jacket, heat gun, etc., not shown) that heats the coating composition in a bath (24), conduits (25) and / or spray gun (s) (23A) so as to maintain the composition in a liquid state during spraying.

Sprayers suitable for spraying the coating composition according to the present invention can be purchased, for example, from Walther Spritz- und Lackiersysteme GmbH, Germany.

As used herein, "roller coating" means that the coating composition is applied directly to the second end using a roll roller. "Roll-to-roll coating" and "reverse roller coating" refer to well-known methods that can be used in the present invention. With reference to FIG. 6, the roller coating system includes a dip cylinder and applicator cylinders (23B), a bath (24), and conduits (25) feeding the coating composition (22) from the bath to the dip cylinder and applicator cylinders (23B). The roller coating system optionally includes a heating system as described above (not shown). The roller coating system can be positioned anywhere on the production line as efficiently as possible. The roller coater can be positioned, for example, on the embossing section such that the applicator cylinder (23B) is pressed against the engraved cylinder (20) or another cylinder (as shown in FIG. 68).

The spray gun (s) (23A) or roller coater (23B) can be adjusted for continuous coating in the machine and axial directions, or intermittent coating (e.g. strips, dots, etc.) in the machine and / or axial direction.

(C) Spiral winding of the continuous web (19) to form a log (34) of the web of absorbent material.

The continuous web (19) is fed from the embossing section (12) to the rewinding section (13), in which the web (19) is spirally wound to form a log (34) of the absorbent material web. The rewinding section (13) includes a perforating module (26), a cutting module (27), a winding module (28) and an extraction module (33). The rewinding section (13) winds a continuous web (19) with the formation of multiple logs (34).

The winding module (28) is designed for winding a continuous web with the formation of web logs (34). The winding module (28) can be of peripheral type (axially wound) or surface type (surface wound). The winding module includes a roller table (29), a first winding roller (30), a second winding roller (31), a third winding roller (32), and a temporary sleeve feeding device (not shown). The log is formed by winding a continuous web onto a temporary sleeve (36) that supports a well-defined axial hollow opening. Temporary sleeves (36) are sequentially fed by the temporary sleeve feeding device through the roller table (29) before the start of a new cycle of log formation. The temporary sleeve (36) can be made, for example, of plastic or cardboard. To grip the second end of the web (19) onto a temporary sleeve (36) at the start of a new production cycle, a "fly glue" (sticking glue) can be used.

The log (34) is held in position during winding by the first, second and third winding rollers (30), (31) and (32) rotating in surface contact with the log (34). One of the winding rollers (30), (31) and (32) can set the rotary motion of the log (surface winding).

Once the desired log diameter is reached (corresponding mainly to a certain web length or number of individual sheets), the continuous web (19) is cut. The received log (34) is separated from the canvas (19), and then the production of a new log begins.

Section (27) cutting is designed to cut the web according to regularly spaced from each other cutting lines, essentially transverse to the machine direction. The cutting of the web is carried out in a transitional phase, namely, when the formation of the first log ends at the end of the log production cycle, and before the start of winding the second subsequent log at the beginning of a new log formation cycle.

Cut lines (not shown) are axial lines drawn across the thickness of the blade (19). Two successive cutting lines define the total length of the blade forming one roll. The distance between two successive cutting lines, that is, the length of the roll, is determined depending on the target product. Typically, the length of the roll and the diameter of the roll are selected depending, for example, on the number of layers forming the web, the basis weight of the individual layers, etc. A single roll of absorbent sheet product may have an overall MD web length of 1 m to 60 m, preferably 1.5 m to 50 m, for example 2 m to 40 m.

The received log (34) is then fed to the extraction module (33), which is designed to pull out the temporary sleeves (36) from the log (34) after the log winding is complete. The temporary sleeves (36), after removal, can be reused using the sleeve feeder.

When the coating composition used in the method of the present invention is an aqueous solution as described herein above, the resulting log can be dried. The resulting log is then separated from the web of absorbent material to remove the temporary sleeve. The resulting log can also be dried after removing the temporary sleeve.

The resulting log is preferably dried until the sanitary paper forming the log contains an amount of water that does not exceed 10% of the total weight of the log, preferably 5% of the total weight of the log. For example, the resulting log can be dried by keeping the log at room temperature (20 ° C to 25 ° C) and an RH (relative humidity) of 10 to 60% for a period of 12 hours.

(D) Optionally cutting the continuous web (19) of absorbent material substantially cross-machine direction to produce single but interlocked sheets.

Before the continuous web (19) is spirally wound in the winding module (29), as described above, the web (19) enters the perforating module (26), if any, which is designed to create a web (19) with regularly spaced spacing from each other by perforation lines (8), substantially transverse to the machine direction, that is, in the axial direction, to form single but interlocking sheets (as shown in FIGS. 3, 4a and 4b).

The perforation line (8) is a line in the axial direction formed through the thickness of the web (19) and includes alternating perforated segments and non-perforated segments (i.e., two perforated segments are separated by one non-perforated segment, and vice versa). Each non-perforated segment forms a bonding zone between two successive portions of a continuous web. Each perforated segment forms a separation zone between two successive sections of a continuous web. If the width of the individual roll is considered, for example, between 10 cm and 30 cm, the length of said non-perforated / perforated segments can be from 1 mm to 15 mm, preferably from 4 mm to 10 mm. Other types of perforation lines are also possible, as far as is essential.

Two successive perforation lines (8) define the length of the individual sheet in the finished absorbent sheet product. The distance between two successive perforation lines, that is, the length of the sheet, is determined depending on the target product. A single sheet can have a machine direction length of 80 mm to 300 mm, for example, 100 mm to 250 mm. For example, a paper towel sheet may be 80 mm to 200 mm long, and a towel such as a household (kitchen) towel or hand towel may be 80 mm to 300 mm long.

(E) Cutting the resulting log (34) into multiple caseless rolls (1).

After winding, the log (34) is fed to a log cutting section (14), in which the log (34) is cut parallel to the machine direction using multiple chopping saws (35) into multiple individual rolls (1). Numerous chopping saws (35) are spaced at regular axial distances from each other so that the log (34) is cut into multiple individual rolls (1) having a certain axial width (i.e., the distance from one edge to the other edge) ... The width of the individual roll (1) is 60 mm to 800 mm, preferably 70 mm to 400 mm, for example 80 mm to 150 mm.

The control module (37) is connected to the perforating module (26), to the cutting module (27) and to the spraying or roller coating system via an interface (38). The control module (37) controls the operation of the punching module (26) and the cutting module (27). In particular, the control module (37) drives the cutting module (27) to cut the web (19) in the transition phase between two successive logs. In addition, the control module (37) controls the operation of the punching module (26) outside the transition phases.

In addition, the control module (37) controls the operation of the spraying or roller coating system, namely the proper application (spraying or roller coating) of the coating composition to the second end of the continuous web (19). The proper application of the coating composition to the second end can be controlled by transmitting, for example, start / stop signals to the application system (spraying or roller coating), which are determined based on the length of the target article and machine parameters, for example, operating speed.

The various rollers (17) are properly positioned to control the path of the continuous web (19) along the paper processing machine (9), within and between the various sections.

(F) Optionally compressing the roll in a direction perpendicular to the axial hollow opening to obtain a coreless roll in a compressed (oval) shape (not shown).

As used herein, "squeezing" means that pressure is applied to the roll in a direction perpendicular to the axial hollow opening to produce a roll having an oval cross-section that requires less storage space. Compression of the roll is preferably performed immediately after winding is completed. A suitable device known in the art can be used to perform the compression. In the present invention, it is possible to use, for example, two converging, synchronously moving conveyor belts described in patent document WO 95/13183, a pneumatically or hydraulically driven pressure plate or other devices.

Thereafter, the individual coreless rolls (1) are packed and prepared for shipment (not shown).

5. Examples

The following test methods were used to evaluate absorbent materials, non-ionic cellulose ethers and the resulting coreless rolls.

5.1. Base weight

The basis weight was determined according to EN ISO 12625-6: 2005, Tissue Paper and Tissue Products, Part 6: Determination of grammage.

5.2. Thickness

The measurement is carried out with a precision micrometer (accuracy 0.001 mm) according to a modified method based on EN ISO 12625-3: 2014 Part 3. For this purpose, measure the distance created between the fixed reference plate and the parallel pressure arm. The diameter of the pressure arm is 35.7 ± 0.1 mm (10.0 cm ² nominal area). The applied pressure is 2.0 kPa ± 0.1 kPa. The pressure lever can be moved at a speed of 2.0 ± 0.2 mm / s.

A suitable device is a thickness gauge type L&W SE050 (manufactured by Lorentzen & Wettre, Europe).

The tissue article to be measured is cut into 20 x 25 cm pieces and conditioned in an atmosphere of 23 ° C, 50% RH (relative humidity) for at least 12 hours.

For measurement, one sheet is placed under a pressure plate, which is then lowered. The sheet thickness is then read 5 seconds after the pressure has been stabilized. The thickness measurement is then repeated nine times with additional samples processed in the same way.

The average of the 10 values obtained is taken as the thickness of one sheet ("thickness of one sheet") of the measured tissue paper (for example, two-layer toilet paper).

5.3. Number average molecular weight

Measurement is performed by gel permeation chromatography (GPC) using a PL-GPC 50 combined GPC / SEC system equipped with a PL aquagel-OH MIXED column, 8 μm particles, 7.5 x 300 mm (both from Agilent Technologies, Europe). The GPC system was calibrated using a pullulan polysaccharide calibration kit from Agilent Technologies (for methyl cellulose), or, depending on the polymer being measured, a suitable calibration kit such as a hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropyl methyl cellulose calibration kit, all from American Polymer Standards Corporation , USA.

A sample of the measured nonionic cellulose ether was dissolved in water at a concentration of 2 mg / ml. The sample was injected (injection volume: 100 μl), and measurement was carried out at a flow rate of 1.0 ml / min and a temperature of 50 ° C using an aqueous buffer solution of 0.05 M NaH ₂ PO ₄ , 0.25 M NaCl, pH 7 as eluent. The retention time (minutes) of cellulose ether was recorded as a peak. The number average molecular weight M̅n of cellulose ether was determined by comparing the recorded retention time with the value for standard (calibration) polymers.

5.4. Viscosity average molecular weight

The measurement can be carried out as follows by viscometry using an Ubbelodhe capillary viscometer equipped with a capillary having an inner diameter of 0.63 mm (both from SI Analytics, Europe).

A sample solution (concentration C ₁ = 10.0 g / l) of cellulose ether in water is prepared and transferred to an Ubbelodhe capillary viscometer. The viscometer is suspended in a thermostated bath for 30 minutes at a temperature of (25 ± 0.1) ° C. The flow time (the time taken for the sample solution to flow between the two calibration marks) is measured. The measurement is repeated five times, and the average of the five values obtained is taken as the flow time of the sample solution. The same measurement is reproduced with a water sample (no cellulose ether). The Hagenbach correction factor was subtracted from the measured flow times (as indicated by SI Analytics).

The relative viscosity z ₁ of a cellulose ether sample can be calculated as follows:

z ₁ = (flow time of sample solution) / (flow time of water)

The measurement is repeated using additional sample solutions with concentrations of C ₂ = 5.0 g / L, C ₃ = 3.33 g / L and C ₄ = 2.5 g / L. Get the relative viscosities z ₂ , z ₃ and z ₄ .

The intrinsic viscosity η can be determined graphically by plotting the relative viscosity (y-axis) versus sample concentration (x-axis), and extrapolating the theoretical straight line back to zero concentration (the line intersects the y-axis at the height of the intrinsic viscosity).

The viscosity average molecular weight M̅v of cellulose ether can be calculated using the Mark-Houwink-Sakurada equation (1) and the cellulose ether K and α constants as shown by Brandrup, J., Immergut, EH, Grulke, EA, Polymer Handbook , 4th edition, John Wiley & Sons, New York, 1999 (hydroxyethyl cellulose: K = 9.53 · 10 ^-3 ml / g, α = 0.87).

(1)

(one)

5.5. Axial stiffness

The measurement was carried out using a vertical dynamometer equipped with a 2.5 kN cell. A suitable instrument is a dynamometer of the type ZwickiLine Z1.0 (from Zwick Roell, Europe).

For measurement, the roll was placed vertically between pressure plates (one of the two flat edges), and pressure was applied in a direction parallel to the axis of the hollow opening. The roll was compressed between the plates at a constant speed of 60 mm / min. Compressive force was measured and plotted against cell displacement (y-axis: compressive force; x-axis: cell displacement). The correlation between the compressive force and the displacement of the cell was determined by linear regression in the area of elastic deformations on the graph. The slope of the linear regression was taken as the axial stiffness of the roll.

The measurement was repeated four times with additional samples, and the average of the five values obtained was taken as the axial stiffness K _{ax of the} roll.

5.6. Radial stiffness

The measurement is carried out using a vertical dynamometer equipped with a 200 N cell. A suitable instrument is a dynamometer of the ZwickiLine Z1.0 type (from Zwick Roell, Europe).

For measurement, the roll to be measured was placed horizontally between the pressure plates (on the round edge), and pressure was applied in a direction perpendicular to the axis of the hollow opening. The roll was compressed between the plates at a constant speed of 60 mm / min. Compressive force was measured and plotted against cell displacement (y-axis: compressive force; x-axis: cell displacement). The correlation between the compressive force and the displacement of the cell was determined by linear regression in the area of elastic deformations on the graph. The slope of the linear regression was taken as the radial stiffness of the roll.

The measurement was repeated four times with additional samples, and the average of the five values obtained was taken as the axial stiffness K _{rad of the} roll.

5.7. Peeling effort

The measurement is carried out using a vertical dynamometer (39) (ZwickiLine Z1.0) equipped with a set of shafts (40) - (43), a clamp (45) and a 50 N cell (not shown) as shown in FIG. 7a, 7b and 7c.

For the measurement, the first inner turns of the coreless roll (44) to be measured were slid onto the upper roll (41) of the roll set, the outermost paper sheet was unwound and placed on the roll set as shown in FIG. 7a and the outermost paper sheet was inserted into the clamp (45). The coils were unwound at a constant speed of 300 mm / min. The peel force required to separate the roll forming paper sheets was measured and plotted as a function of cell displacement. The maximum force and the average force required to delaminate the sample were recorded within the displacement interval. The peel force measurement was then repeated four times on additional samples.

The average of the five values of the maximum force obtained is taken as the peeling force of the coated continuous web.

5.8. Disintegrability

Disintegrability (degradability) was determined according to NF Q34-20: 1998, Sanitary and Domestic Articles - Bathroom Tissue - Determination of Disintegration.

5.9. Raw materials, chemicals and paper converting machine

Absorbent material

Three-ply tissue paper (1) (standard) having a basis weight of 55.6 g / m ² and a thickness of 0.62 mm (manufactured by SCA) was used as a continuous web of absorbent material in Control Example 1 and Examples 1-3. ...

Three-layer tissue paper (2) (standard) having a basis weight of 53.6 g / m ² and a thickness of 0.63 mm (manufactured by SCA) was used as a continuous web of absorbent material in Control Example 2 and Examples 4-8 ...

Three-ply tissue paper (continuous web) (1) and (2) was prepared using a standard converting machine by combining single-ply tissue paper to form a finite number (3) layers as follows:

The first unwinding section feeds the first layer of tissue paper from a first machine-wound initial roll having a width of 0.6 m. The second unwinding section feeds a second layer of tissue paper from a second machine-wound initial roll having a width of 0.6 m. the section feeds the third layer of tissue paper from a third machine wound original roll having a width of 0.6 m. The layers of tissue paper are fed into the embossing section. Sanitary papers are layered on top of each other and combined (bonded) using glue in the embossing section to form a continuous web of absorbent material. The engraved cylinder performs a two-level embossing in the log from superimposed base absorbent webs. The adhesive used to bond the layers was Swift®tak 1004 at 0.5 g / m ² .

The resulting three-layer continuous web of absorbent material was fed into a rewinding section.

Chemicals

The following are the chemicals used in the following examples:

- for the cover composition:

> methyl cellulose from Sigma-Aldrich with a viscosity of about 400 cps (2% solution in water at 20 ° C) and a number average molecular weight of about 40,000 (as determined by the GPC method);

> hydroxyethyl cellulose from Sigma-Aldrich with a viscosity average molecular weight of about 90,000 (as determined by viscometry);

> hydroxyethyl cellulose from Sigma-Aldrich with a viscosity average molecular weight of about 720,000 (as determined by viscometry);

> hydroxypropyl cellulose from Sigma-Aldrich with a number average molecular weight of about 10,000 (as determined by the GPC method);

> hydroxypropyl methylcellulose from Sigma-Aldrich with a hydroxypropyl group content of about 9% and a viscosity of about 15 cps (2% solution in water at 25 ° C).

> Blanose® 7ECL1 carboxymethyl cellulose from Ashland.

- adhesive materials:

> Swift®tak 1004 from H.B. Fuller (used to bond layers);

> Tissue Tak 604 from Henkel (fly glue used for winding).

Paper converting machine

A standard tissue paper machine has been adapted to make toilet paper having three layers. The machine included two unwinding sections, an embossing section, a rewinding section and a log cutting section.

The embossing section included an engraved cylinder, an associated rubber cylinder, and an adhesive dispenser. The engraved cylinder was engraved with a microstructural pattern uniting a variety of embossed points. The glue dispenser contained a bath, an applicator and an immersion cylinder.

The rewinding section included a perforating module, a cutting module, a winding module, and an extracting module. The perforating module included a perforating roller and a stationary support shaft. The cutting module included a cutting roller and a stationary support shaft.

In addition, the rewinding section was equipped with a spray system consisting of four WA520 spray guns (from Walther Pilot) with a nozzle diameter of 1.5 mm and operating at a pressure of 1.5, 2.0 or 2.5 bar (0.15 , 0.2 or 0.25 MPa), baths and pipelines supplying the coating composition from the bath to the spray guns.

Sprayers were positioned between the cutter and winder so that the cover composition was applied / sprayed onto the underside of the continuous web of absorbent material upstream of the cut line at the start of the log, thereby defining the first end of the web (i.e., log / roll turns close to to the axial hollow opening).

The log cutting section included numerous log cutting saws.

The various rollers are properly positioned to control the trajectory of the base absorbent log sheet along the paper machine, within and between the different sections. The base absorbent log webs are moved in the paper converting machine according to the machine direction (MD) from the unwinding units, towards the embossing unit, to the rewinding unit and to the log cutting unit.

The control module was connected to the punching module, the cutting module and the spray guns via an interface. The control module controlled the operation of the punching module and cutter module, as well as the proper deposition of the coating composition on the second end.

The machine speed was maintained at 100 m / min throughout the tests.

Test Example 1 (test toilet paper 1)

To obtain the desired tubeless toilet paper roll, a three-layer continuous web (1) of absorbent material (basis weight: 55.6 g / m ² , thickness: 0.62 mm) was prepared as described above and was pulled from the embossing section and fed to the rewinding section.

In the rewinding section, the continuous web first entered a perforating module, which pinched the web to form perforation lines oriented across the MD and regularly spaced apart from each other in the CD direction. The size of the perforated segment was 4 mm and the size of the non-perforated segment was 1 mm. The distance between the two perforation lines was 125 mm.

After pinching, the web of absorbent material entered a winding unit, in which the web was picked up by a temporary sleeve (outer diameter: 38 mm) using Tissue Tak 604 as the "fly glue". The continuous web was then wound onto a core to form a log having a diameter of 120 mm (corresponding to 140 perforated sheets; approximate total web length: 17,500 mm).

The resulting log was separated from the web of absorbent material in a cutting module, which cut the web across the MD. The resulting log was kept at a temperature of 20-22 ° C, 50% relative humidity for a period of 12 hours.

After incubation, the temporary sleeve was removed from the log in the extraction module. The resulting log was cut parallel to the MD with multiple saws to cut the log into multiple individual rolls having a width of 99 mm.

Test Example 2 (test toilet paper 2)

A coreless roll was obtained in the same manner as described above in Control Example 1, except that a three-layer continuous web (2) of absorbent material (basis weight: 53.6 g / m ² , thickness: 0.47 mm) was obtained as described above, which was pulled from the embossing section and fed to the rewinding section.

The resulting log, having a diameter of 120 mm, was cut parallel to the MD with multiple saws to cut the log into multiple individual rolls having a width of 99 mm.

Example 1 (hydroxypropyl methylcellulose toilet paper)

A coating composition was prepared by dissolving 15 cps viscosity hydroxypropyl methylcellulose (HPMC) in water at a concentration of 3.7% by weight. The resulting coating composition was fed into spray guns and applied at room temperature (22 ° C).

To obtain the desired tubeless roll of toilet paper, a tubeless roll was obtained in the same manner as described above in Control Example 1, except that after pinching / cutting and before winding the web, the coating composition was applied (sprayed) using spray guns (pressure: 1, 5 bar (0.15 MPa)) for a length of about 1800 mm (i.e. about 15 sheets) upstream of the cut line.

The amount of HPMC applied to the second end (length: 1800 mm; that is, about 10% of the total length of the web) was 0.019 g / roll (solids content of the HPMC applied to one individual roll, that is, after cutting the log).

Example 2 (hydroxypropyl methylcellulose toilet paper)

A sleeveless roll was prepared in the same manner as above in Example 1, except that the coating composition was applied to a length of about 1800 mm at a pressure of 2.5 bar (0.25 MPa). The amount of HPMC applied to the second end (length: 1800 mm) was 0.081 g / roll (solids content of the HPMC applied to one individual roll).

Example 3 (hydroxypropyl methylcellulose toilet paper)

A coreless roll was prepared in the same manner as in Example 1 above, except that the coating composition was applied over a length of about 3500 mm (i.e., about 28 sheets) under a pressure of 2.0 bar (0.2 MPa). The amount of HPMC applied to the second end (length: 3500 mm; that is, about 20% of the total length of the web) was 0.099 g / roll (solids content of the HPMC applied to one individual roll).

Example 4 (methylcellulose toilet paper)

The coating composition was prepared by dissolving 400 cps methylcellulose in water at a concentration of 2% by weight. The resulting coating composition was fed into spray guns and applied at room temperature.

To obtain the desired tubeless roll of toilet paper, a tubeless roll was produced in the same manner as described above in Control Example 2, except that after pinching / cutting and before winding the web, the coating composition was applied (sprayed) using spray guns (pressure: 2, 5 bar (0.25 MPa)) for a length of about 1800 mm (i.e. about 15 sheets) upstream of the cut line.

The amount of MC applied to the second end (length: 1800 mm) was 0.066 g / roll (solids content of MC applied to one individual roll).

Example 5 (hydroxyethyl cellulose toilet paper, M̅v = 90,000)

The coating composition was prepared by dissolving hydroxyethyl cellulose having a viscosity average molecular weight of 90,000 (HEC90) in water at a concentration of 6% by weight. The resulting coating composition was fed into spray guns and applied at room temperature.

A linerless roll was prepared in the same manner as described above in Example 4, except that the above-described coating composition was applied at a pressure of 1.5 bar (0.15 MPa). The amount of HEC90 applied to the second end (length: 1800 mm) was 0.09 g / roll (solids content of HEC90 applied to one individual roll).

Example 6 (hydroxypropyl cellulose toilet paper, M̅v = 720,000)

The coating composition was prepared by dissolving hydroxyethyl cellulose having a viscosity average molecular weight of 720,000 (HEC720) in water at a concentration of 4% by weight. The resulting coating composition was fed into spray guns and applied at room temperature.

A sleeveless roll was prepared in the same manner as described above in Example 4 using the above-described coating composition. The amount of HEC720 applied to the second end (length: 1800 mm) was 0.03 g / roll (solids content of HEC720 applied to one individual roll).

Example 7 (hydroxypropyl cellulose toilet paper)

The coating composition was prepared by dissolving hydroxypropyl cellulose having a number average molecular weight of 10,000 (HPC) in water at a concentration of 6% by weight. The resulting coating composition was fed into spray guns and applied at room temperature.

A sleeveless roll was prepared in the same manner as described above in Example 4 using the above-described coating composition. The amount of HPC applied to the second end (length: 1800 mm) was 0.06 g / roll (solids content of HPC applied to one individual roll).

Example 8 (hydroxypropyl methylcellulose toilet paper)

The coating composition was prepared by dissolving HPMC in water at a concentration of 3.7% by weight. The resulting coating composition was fed into spray guns and applied at room temperature.

A linerless roll was prepared in the same manner as described above in Example 4, except that the above-described coating composition was applied at a pressure of 2.0 bar (0.2 MPa). The amount of HPMC applied to the second end (length: 1800 mm) was 0.042 g / roll (solids content of the HPMC applied to one individual roll).

Comparative Example 1 (carboxymethyl cellulose toilet paper)

The coating composition was prepared by dissolving Blanose® 7ECL1 carboxymethyl cellulose (CMC) (about 90,000 weight average molecular weight) in water at a concentration of 5% by weight. The resulting coating composition was fed into spray guns and applied at room temperature.

A sleeveless roll was prepared in the same manner as in Example 4 above using the above-described coating composition. The amount of CMC applied to the second end (length: 1800 mm) was 0.17 g / roll (solids content of CMC applied to one individual roll).

The properties of the resulting rolls of toilet paper were evaluated according to the procedures described above. More specifically, the stiffness characteristics of the rolls obtained in Test Example 1 and Examples 1, 2 and 3 were evaluated. The results are shown in Table 1 below. In addition, the delamination and degradation characteristics of the rolls obtained in Test Example 2 and Examples 4, 5, 6 were evaluated. , 7 and 8. The results are shown in Table 2 below.

Table 1

Example Cover composition amount (g / roll) Axial stiffness K _ax (N / mm) Radial stiffness K _rad (N / mm) Test Case 1
raw - 190 0.41 Example 1
HPMC processing 0.019 251 0.43 Example 2
HPMC processing 0.081 279 0.53 Example 3
HPMC processing 0.066 299 0.46

table 2

Example Peeling force (N) Perforation breaks and / or damage to sheets Decomposition
(seconds) Test Case 2
raw 0.16 No eleven Example 4
MC processing 0.73 No twenty Example 5
HEC90 processing 0.64 No 12 Example 6
HEC720 processing 0.43 No 13 Example 7
HPC processing 0.47 No 12 Example 8
HPMC processing 0.37 No - Comparative Example 1
CMC processing 1.75 yes (5 out of 5) 6

These test data indicate that the application of the coating composition according to the present invention resulted in increased stiffness while the peel force of the rolls was maintained within an acceptable range. The coating composition allows the first inner turns to be stably maintained and therefore the rolls of the present invention are not prone to flattening. This can be achieved with fairly low total amounts of nonionic cellulose ether. The rolls of the present invention can be unwound down to the last sheet without tearing and / or damaging the sheets (i.e., without causing perforations to break and / or damage to the sheets when measuring the peel force.

In addition, the good stiffness characteristics of the rolls according to the present invention are beneficial during the manufacturing process in which the rolls are subjected to radial compression (for example, radial force is applied by the saws to cut the log in the cutting module), as well as during storage and transport, in which the rolls are subjected to axial compression, such as axial loads that occur when packaged roll products are stacked on pallets for storage, shipping, etc.

On the other hand, the use of a coating composition containing ionic cellulose ether (CMC) results in a roll in which the sheets of the first inner windings are firmly adhered (adhered) to each other. As a result, it was impossible to unwind the roll without tearing and / or damaging the last sheets. The roll of the control example (to which no coating composition was applied) was prone to flattening. This leads to problems during packaging and gives consumers a feeling of reduced quality.

Claims (34)

1. A coreless roll of absorbent sheet product formed from a spirally wound continuous web of absorbent material having a first end and a second end, the web of absorbent material being wound so as to create an axial hollow opening positioned in the center of the coreless roll and extending from one edge to the other end of the sleeveless roll, and in such a way that the first end is located on the outside of the roll, and the second end is located at the axial hollow opening and is not more than 40% of the entire length of the continuous web of absorbent material; wherein the second end of the continuous web of absorbent material includes a cover composition containing a nonionic cellulose ether. 2. A linerless roll according to claim 1, obtained by applying a coating composition to the second end of a continuous web of absorbent material. 3. A coreless roll according to claim 1 or 2, wherein the nonionic cellulose ether has a number average molecular weight of 1,000 to 1,000,000, preferably 2,000 to 500,000, more preferably 3,000 to 200,000, more preferably 5,000 to 100,000. 4. The coreless roll according to claim 1 or 2, wherein the nonionic cellulose ether has a viscosity average molecular weight of 5,000 to 2,000,000, preferably 10,000 to 1,500,000, more preferably 30,000 to 1,000,000. 5. Sleeveless roll according to any one of paragraphs. 1-4, in which the nonionic cellulose ether has a water solubility at 25 ° C. of at least 40 g / l. 6. Sleeveless roll according to any one of paragraphs. 1-5, in which the nonionic cellulose ether is an alkyl cellulose ether such as methyl cellulose or ethyl cellulose. 7. Sleeveless roll according to any one of paragraphs. 1-5, in which the nonionic cellulose ether is a hydroxyalkyl cellulose ether such as hydroxyethyl cellulose or hydroxypropyl cellulose. 8. Sleeveless roll according to any one of paragraphs. 1-5, in which the nonionic cellulose ether is a combination of an alkyl cellulose ether and a hydroxyalkyl cellulose ether. 9. Sleeveless roll according to any one of paragraphs. 1-8, wherein the coating composition comprises: (a) at least 50 wt%, preferably at least 65 wt%, more preferably at least 80 wt% nonionic cellulose ether; (b) not more than 50 wt.%, preferably not more than 35 wt.%, more preferably not more than 20 wt.% additional additives such as plasticizers, hardening agents, flavors and colorants; in each case based on the total solids content of the coating composition. 10. Sleeveless roll according to any one of paragraphs. 1-9, in which the coating composition is applied as an aqueous solution, the aqueous solution preferably contains non-ionic cellulose ether in an amount of at least 0.1 wt.%, More preferably at least 0.5 wt.%, Based on the total weight of an aqueous solution. 11. Sleeveless roll according to any one of paragraphs. 1-10, wherein the coating composition is free of hydroxyl-terminated polyether and / or is free of saccharides other than nonionic cellulose ether. 12. Sleeveless roll according to any one of paragraphs. 1-11, in which the axial hollow opening has a circumferential periphery and the coating composition is applied circumferentially, preferably such that the resulting coating occupies at least 50% of the second end, preferably at least 75%, more preferably at least 95% second end. 13. Sleeveless roll according to any one of paragraphs. 1-12, in which the coating composition is applied continuously in the machine direction and axial direction or intermittently in the machine direction and / or axial direction. 14. Sleeveless roll according to any one of paragraphs. 1-13, in which the second end consists of at least one turn, preferably at least two turns, preferably at least three turns, for example 3 to 50 turns, for example 3 to 30 turns or 4 to 40 turns, preferably from 3 to 30 turns, the turn being formed by one turn of the spirally wound continuous web around an axial hollow opening. 15. Sleeveless roll according to any one of paragraphs. 1-13, in which the second end occupies at least 5%, preferably at least 10%, more preferably at least 15% of the total length of the continuous web of absorbent material in the machine direction. 16. Sleeveless roll according to any one of paragraphs. 1-15, in which the amount of nonionic cellulose ether is 0.001 to 20 g / roll, preferably 0.005 to 10 g / roll, more preferably 0.005 to 5 g / roll, in particular 0.01 to 2 g / roll ... 17. Sleeveless roll according to any one of paragraphs. 1-16, in which the absorbent material web consists of 1 tissue paper layer or 2 to 6, in particular 2 to 5, superposed tissue layers. 18. Sleeveless roll according to any one of paragraphs. 1-17 in compressed form. 19. Sleeveless roll according to any one of paragraphs. 1-18, which is an absorbent article selected from the group consisting of sanitary napkins, towels such as household towels, kitchen or hand towels, toilet papers, wiping papers, handkerchiefs and facial tissues, and is absorbent the article is preferably toilet paper. 20. A method of manufacturing a coreless roll of an absorbent sheet product, comprising: - moving a continuous web of absorbent material having a first end and a second end, and the second end is not more than 40% of the total length of the continuous web of absorbent material; optionally cutting the continuous web of absorbent material substantially cross-machine direction to produce single but interlocked sheets; - application of a coating composition as defined in any one of paragraphs. 1 and 3-11, at the second end; - spiral winding of a continuous web of absorbent material so as to form a log of the web of absorbent material, the web of absorbent material being wound in such a way as to define an axial hollow opening positioned in the center with respect to the log and extending from one edge of the log to its other edge, and thus that the first end is on the outside of the log and the second end is at the axial hollow opening; and - cutting the log into many caseless rolls. 21. The manufacturing method of claim 20, wherein the continuous web of absorbent material is constituted by 1 layer of tissue paper or 2 to 6 superimposed layers of tissue paper. 22. The manufacturing method of claim 20, wherein the continuous web of absorbent material is composed of 2 to 5 superimposed layers of tissue paper. 23. A method of manufacturing according to any one of paragraphs. 20-22, additionally including - subjecting a tubeless roll to compression in a direction perpendicular to the axial hollow opening to obtain a tubeless roll in a compressed form. 24. The use of a sleeveless roll according to any one of paragraphs. 1-18 as toilet paper, household towel, hand towel, kitchen towel, wiping paper, facial tissue, handkerchief, or sanitary napkin.

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