TISSUE PAPER PRODUCTS, ROLLS AND STACKS OF TISSUE PAPER PRODUCTS, AND MANUFACTURING METHODS

Abstract

Disclosed is a tissue paper product including at least three plies with a top ply and bottom ply as outermost plies, and an inner ply between the top and bottom plies, a basis weight of the tissue paper product being 30-150. The top ply being embossed with at least two types of embossments including first embossments with a first height and second embossments with a second height, the first height being larger than the second height, and the bottom ply is embossed, the inner ply and the top ply being bonded with the bottom ply at tips of the first embossments with an adhesive, such as a lamination glue, or the inner ply, the top ply, and the bottom ply are ply-bonded with mechanical bonding, at least one of the top ply and the bottom ply being embossed by a heated embossing roll.

Claims

1. A tissue paper product, such as toilet paper or household towel, wherein the tissue paper product comprises at least three plies including a to p ply, a bottom ply, and an inner ply located between the top ply and the bottom ply, the top ply and the bottom ply being outermost plies of the tissue paper product, a basis weight of the tissue paper product being in a range of 30 to 150, optionally 30 to 100 g/m.sup.2, or 35 to 80 g/m.sup.2, or 40 to 65 g/m.sup.2, wherein the top ply has been embossed and comprises at least two types of embossments including first embossments with a first height and second embossments with a second height, the first height being larger than the second height, wherein the inner ply has not been embossed, wherein the bottom ply has been embossed, the top ply, the inner ply, and the bottom ply are ply-bonded with an adhesive, such as a lamination glue, and/or water and/or mechanical bonding, such as edge embossing, wherein at least one of the top ply and the bottom ply has been embossed by a heated embossing roll.

2. The tissue paper product of claim 1, wherein at least one of the plies of the tissue paper product, optionally all of the plies of the tissue paper product, are made of Conventional Wet Press (CWP) paper.

3. The tissue paper product of claim 1, wherein the tissue paper product comprises a number of plies between three and six.

4. The tissue paper product of claim 1, wherein the tissue paper product comprises exactly three plies.

5. The tissue paper product of claim 1, wherein the tissue paper product comprises exactly four plies comprising the top ply, the bottom ply, the inner ply, and an another ply, wherein optionally the another ply and the top ply are embossed together or the another ply and the bottom ply are embossed together, or the another ply and the inner ply are combined with the top ply and ply-bonded with the bottom ply at tips of the first embossments with an adhesive, such as lamination glue.

6. The tissue paper product of claim 1, wherein the tissue paper product comprises exactly five or six plies.

7. The tissue paper product of claim 1, wherein the inner ply optionally, is only partially embossed at locations where it is ply-bonded with the top ply and the bottom ply.

8. The tissue paper product of claim 1, wherein the top ply includes exactly two types of embossments, being decorative embossments with an embossing height in a range of 0.2 mm to 2.0 mm, optionally 0.8 mm to 1.4 mm, and micro-embossments with an embossing height in a range of 0.1 mm to 1.2 mm, wherein wherein the decorative embossments cover between 1% and 20% of a total surface of the top ply, optionally between 2% and 10%, or between 3% and 6%, wherein the tissue paper product comprises at least one region in which a density of the micro-embossments is, in the area of the top ply without the decorative embossments, in a range of 25 to 120 dots/cm.sup.2, optionally 40 to 100 dots/cm.sup.2, or 50 to 80 dots/cm.sup.2, and wherein, optionally, the bottom ply includes exactly one or two types of embossments and wherein the density of the total number of embossments of the bottom ply is in the range of from 25 to 120 dots/cm.sup.2, optionally 40 to 100 dots/cm.sup.2, or 50 to 80 dots/cm.sup.2.

9. The tissue paper product of claim 1, wherein the inner ply and the top ply are ply-bonded with the bottom ply by the adhesive applied only in an area comprising, optionally consisting of, the tips of the first embossments, optionally at least 95%, 98%, or even at least at 99% of the tips of the first embossments.

10. The tissue paper product of claim 1, wherein the inner ply is a creped ply having a basis weight in the range of 13 to 30 g/m.sup.2, optionally 16 to 28 g/m.sup.2, or 18 to 24 g/m.sup.2, wherein the creped ply comprises creping lines extending along a first direction and parallel ribs and valleys extending along a second direction, an angle between the first direction and the second direction is in a range of 80° to 100°, the ribs and valleys provide an average core roughness Rk in the range of 10 to 300 μm, and a number of peaks is in the range of 4 to 12 per cm as measured in the first direction.

11. A roll of tissue paper product made of a spirally wound continuous web of the tissue paper product of claim 1, the tissue paper product having a first end and a second end, the web of tissue paper product being wound such as to define an axially extending inner hole centrally positioned relative to the roll and such that the first end is located on the outer side of the roll and the second end is located at the inner hole.

12. The roll of tissue paper product of claim 11, wherein a diameter of the roll is in a range of from 85 to 200 mm.

13. A stack of unfolded sheets or of folded sheets, optionally of interfolded sheets, made of tissue paper product of claim 1.

14. A method of manufacturing a tissue paper product, such as toilet paper or household towel, comprising at least three plies, comprising the steps of: feeding at least three plies, including a first ply, a second ply, and a third ply, with a basis weight in the range of from 13 to 30 g/m.sup.2, optionally 16 to 28 g/m.sup.2, or 18 to 24 g/m.sup.2, respectively; embossing the first ply on a first embossing roll with embossing protrusions with a first height h1 to form first embossments on the first ply, embossing the first ply on a second embossing roll with second embossing protrusions with a second height h2, the first height h1 being larger than the second height h2, wherein the embossing on the second embossing roll is carried out before or after the embossing on the first embossing roll; embossing the second ply on a third embossing roll with embossing protrusions with a third height h3; ply-bonding the first ply, the second ply, and the third ply, and optionally further plies, such that the first ply and the second ply are outermost plies and the third ply is an inner ply, using an adhesive, such as a lamination glue, and/or water, and/or mechanical bonding, such as edge embossing; wherein the inner ply is not embossed, and wherein at least one of the first embossing roll, the second embossing roll, and the third embossing roll is a heatable roll.

15. A method of manufacturing a tissue paper product, such as toilet paper or household towel, comprising at least three plies, comprising the steps of: feeding at least three plies, including a first ply, a second ply, and a third ply, with a basis weight in the range of from 13 to 30 g/m.sup.2, optionally 16 to 28 g/m.sup.2, or 18 to 24 g/m.sup.2, respectively; embossing the first ply on a primary embossing roll with first embossing protrusions with a first height h1 to form first embossments on the first ply and with second embossing protrusions with a second height h2, the first height h1 being larger than the second height h2; embossing the second ply on a secondary embossing roll with embossing protrusions with a third height h3; ply-bonding the first ply, the second ply, and the third ply, and optionally further plies, such that the first ply and the second ply are outermost plies and the third ply is an inner ply, using an adhesive, such as a lamination glue, and/or water, and/or mechanical bonding, such as edge embossing; wherein the inner ply is not embossed, and wherein at least one of the primary embossing roll and the secondary embossing roll is a heatable roll.

16. The method of manufacturing a tissue paper product of claim 14, wherein the at least one heatable roll is heated from the inside or outside by a heating means, the heating means optionally comprising heat carrying fluid and/or relying on induction and/or infrared heating, to a surface temperature in the range of 80° C. to 170° , optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°.

17. The method of manufacturing a tissue paper product of claim 14, wherein the first ply or the second ply is moistened with an amount of liquid in the range of 2% to 12% of the basis weight of the first ply, or optionally 4% to 10% of the basis weight of the first ply, prior to being embossed with a heated embossing roll.

18. The method of manufacturing a tissue paper product of claim 1, comprising the step of applying an adhesive, such as lamination glue, to the first ply and/or the third ply.

19. The method of manufacturing a tissue paper product of claim 14, wherein an embossing load during the embossing the first ply and/or the second ply reaches a range of from to 1 to 50 kg/cml, or optionally 5 to 40 kg/cml.

20. The method of manufacturing a tissue paper product of claim 14, wherein the third ply is provided as a creped ribbed web with a basis weight in the range of 13 to 30 g/m.sup.2, optionally 16 to 28 g/m.sup.2, or 18 to 24 g/m.sup.2, the creped ribbed web being a web comprising creping lines extending along a first direction and parallel ribs and valleys extending along a second direct ion, wherein an angle between the first direction and the second direction is in a range of 80° to 100°, the ribs and valleys provide an average core roughness Rk in the range of 10 to 300 μm, and a number of peaks is in the range of 4 to 12 per cm as measured in the first direction.

21. The method of manufacturing a tissue paper product of claim 20, wherein the creped ribbed web is provided by manufacturing a web using a creping blade provided with a rake edge comprising indentations, the rake edge optionally comprising 4 to 12 indentations over a rake edge length and/or the indentations optionally having a depth in a range of 0.1 mm to 1.2 mm.

22. A tissue paper product manufactured according to the method of claim 14.

23. A roll of a tissue paper product, such as toilet paper or household towel, made of a spirally wound continuous web of the tissue paper product having a first end and a second end, the web of the tissue paper product being wound such as to define an axially extending inner hole centrally positioned relative to the roll and such that the first end is located on the outer side of the roll and the second end is located at the inner hole, the tissue paper product being the tissue paper product of claim 24.

24. A stack of unfolded sheets or of folded sheets, optionally of interfolded sheets, made of tissue paper product of claim 22.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0121] For a better understanding of the present disclosure and to show how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0122] The description is given with reference to the accompanying drawings, in which:

[0123] FIGS. 1 to 3 are sectional views of a first embodiment, a second embodiment, and a third embodiment, of a tissue paper product in accordance with the present disclosure, each of which comprises three plies (wherein plies that have been embossed using a heated embossing roll are illustrated with thicker lines than other pies); and

[0124] FIGS. 4 to 12 are sectional views of fourth to twelfth embodiments of a tissue paper product in accordance with the present disclosure, each of which comprises four plies (wherein plies that have been embossed using a heated embossing roll are illustrated with thicker lines than other pies).

[0125] The embodiments of FIGS. 1 to 3 comprise three plies: a top ply 1, a bottom ply 2, and an inner ply 3. A basis weight of the three-ply tissue paper product is in each case in a range of 30 to 150, optionally 30 to 100 g/m.sup.2, or 35 to 80 g/m.sup.2, or 40 to 65 g/m.sup.2.

[0126] The top ply 1 of each of the embodiments is embossed with two types of embossments with different heights. The bottom ply 2 is in each case embossed with one type of embossments.

[0127] For each of the embodiments of FIGS. 1, 2, and 3, the three plies are ply-bonded, for example, using an adhesive applied to the inner ply 3. However, according to other embodiments, the adhesive may, e.g., be applied to tips of the higher embossments of the top ply 1 and/or to tips of embossments of the bottom ply 2 (in addition to or alterative to the application to the inner ply 3).

[0128] In addition, the inner ply 3 of each of the embodiments of FIGS. 1, 2, and 3 has not been pre-embossed. In other words, it is unembossed, at least in the sense of not having been embossed prior to the final ply-bonding having been effected.

[0129] Moreover, all three plies of each of the embodiments of FIGS. 1, 2, and 3 are made of Conventional Wet Press (CWP) paper.

[0130] At least one of the plies of the tissue paper products of FIGS. 1, 2, and 3 has been embossed using a heated embossing roll. The respective ply or plies is illustrated with a thicker line than other plies, which were not embossed or embossed with a non-heated roll.

[0131] In the case of the embodiment of FIG. 1, the bottom ply 2 has been embossed by a heated embossing roll that was heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°. The top ply 1 of the embodiment of FIG. 1 was embossed with a non-heated embossing roll.

[0132] In the case of the embodiment of FIG. 2, the top ply 1 has been embossed by a heated embossing roll that was heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°. The bottom ply 2 of the embodiment of FIG. 2 was embossed with a non-heated embossing roll.

[0133] Both the top ply 1 and the bottom ply 2 of the embodiment of FIG. 3 were embossed by respective heated embossing rolls that were heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°.

[0134] For each of the embodiments of FIGS. 1, 2, and 3, the density of the micro-embossments on the top ply 1 and on the bottom ply 2, respectively, of the embodiments of FIGS. 1, 2, and 3 are provided in a density which lies in a range of 25 to 120 dots/cm.sup.2. In particular, the first plies 1 in each case comprise first embossments with a first height h1 and second embossments with a second height h2, wherein the first height h1 is larger than the second height h2 (h1>h2). The second embossments are illustrated in the regions 4 and 5, whereas the first embossments (with the larger height) are illustrated in the region 6. The three plies 1, 3, and 2 are ply-bonded at tips of the first embossments (i.e., in the region 6 of the respective figure).

[0135] Each of the tissue paper products of FIGS. 1, 2, and 3 has particularly good absorption capacity, a large thickness (as compared to conventional products with a similar strength), and a high (tensile) strength (as compared to conventional products with a similar thickness), both MD tensile strength and CD tensile strength. Specifically, the tissue paper products of FIGS. 1, 2, and 3 have a good wetness shape memory, i.e., the embossments disappear less than in comparable conventional products when the product has been wet.

[0136] The embodiments of FIGS. 4 to 12 comprise four plies. Again, a ply embossed with a heated embossing roll is in each case illustrated with a thicker line than plies that were not embossed or embossed with a non-heated roll.

[0137] In the case of each of the embodiments of FIGS. 4 to 12, a basis weight of a basis weight of the four-ply tissue paper product is in each case in a range of 30 to 150, optionally 30 to 100 g/m.sup.2, or 35 to 80 g/m.sup.2, or 40 to 65 g/m.sup.2. The top ply 1, 10 of each of the embodiments was embossed with two types of embossments with different heights. The bottom ply 2, 20 is in each case embossed with one type of embossments. In each case, the four plies are ply-bonded, for example, using an adhesive applied to the inner ply 3. However, according to other embodiments, the adhesive may, e.g., be applied to tips of the higher embossments of the top ply 1, 10 and/or to tips of embossments of the bottom ply 2 (in addition to or alterative to the application to the inner ply 3).

[0138] The inner ply 3 (or inner plies 30, 31) of each of the embodiments of FIGS. 4 to 12 has not been pre-embossed. In other words, it is unembossed at least in the sense of not having been embossed prior to the final ply-bonding having taken place. Moreover, all four plies of each of the embodiments of FIGS. 4 to 12 are made of Conventional Wet Press (CWP) paper.

[0139] In the case of the embodiment of FIG. 4, the top ply 10 has been pre-embossed together with another ply 11. Thus, both the top ply 1 and the another ply 11 comprise two types of embossments: first embossments with a first height h1 and second embossments with a second height h2, wherein the first height h1 is larger than the second height h2 (h1>h2). The second embossments are illustrated in the regions 4 and 5, whereas the first embossments (with the larger height) are illustrated in the region 6. The four plies 10, 11, 3, and 2 are ply-bonded at tips of the first embossments (i.e., in the region 6 of FIG. 4).

[0140] The top ply 10 and the another ply 11 have been embossed with a non-heated roll. The bottom ply 2 has been embossed by a heated embossing roll that was heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°.

[0141] In the case of the embodiment of FIG. 5, the top ply 10 has been embossed together with another ply 11 by a heated embossing roll that was heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°. The bottom ply 2 of the embodiment of FIG. 5 was embossed with a non-heated embossing roll. The top ply 1 and the another ply 11 comprise two types of embossments: first embossments with a first height h1 and second embossments with a second height h2, wherein the first height h1 is larger than the second height h2 (h1>h2). The second embossments are illustrated in the regions 4 and 5, whereas the first embossments (with the larger height) are illustrated in the region 6. The four plies 10, 11, 3, and 2 are ply-bonded at tips of the first embossments (i.e., in the region 6 of FIG. 5).

[0142] The top ply 10 and another ply 11 of the embodiment of FIG. 6 were embossed together with a heated embossing rolls that were heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°. In addition, also the bottom ply 2 of the embodiment of FIG. 6 was embossed by a heated embossing roll that was heated to a temperature in the range of 80° C. to 170° , optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°. The top ply 10 and the another ply 11 comprise first embossments with a first height h1 and second embossments with a second height h2, wherein the first height h1 is larger than the second height h2 (h1>h2). The second embossments are illustrated in the regions 4 and 5, whereas the first embossments (with the larger height) are illustrated in the region 6. The four plies 10, 11, 3, and 2 are ply-bonded at tips of the first embossments (i.e., in the region 6 of FIG. 6).

[0143] Also the basis weight of the embodiments of FIGS. 7, 8, and 9, is in each case in a range of 30 to 150, optionally 30 to 100 g/m.sup.2, or 35 to 80 g/m.sup.2, or 40 to 65 g/m.sup.2. The embodiments of FIGS. 7, 8, and 9 differ from those of FIGS. 4, 5, and 6, for example, in that they all have two inner plies 30 and 31. These have in each case been bonded to each other before the final ply-bonding of all four plies of the respective tissue paper product. In other words, the inner plies 30 and 31 are unembossed at least in the sense of not having been embossed prior to the final ply-bonding having taken place.

[0144] All four plies of each of the embodiments of FIGS. 7, 8, and 9 are made of Conventional Wet Press (CWP) paper.

[0145] The top ply 1 of each of the embodiments of FIGS. 7, 8, and 9 is embossed with two types of embossments with different heights: first embossments with a first height h1 and second embossments with a second height h2, wherein the first height h1 is larger than the second height h2 (h1>h2). The second embossments are illustrated in the regions 4 and 5, whereas the first embossments (with the larger height) are illustrated in the region 6. The four plies 1, 30, 31, and 2 are ply-bonded at tips of the first embossments (i.e., in the region 6 of FIGS. 7, 8, and 9, respectively). The bottom ply 2 is in each case embossed with one type of embossments. In each case, the three plies are ply-bonded, for example, using an adhesive applied to the side of the ply 31 facing the bottom ply 2, 2″. However, according to other embodiments, the adhesive may, e.g., be applied to tips of the higher embossments of the top ply 1, 1″ and/or to tips of embossments of the bottom ply 2, 2″, to the other side of the inner ply 31 and/or to the inner ply 30, etc.

[0146] In the case of the embodiment of FIG. 7, the bottom ply 2 has been embossed by a heated embossing roll that was heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°. The top ply 1 of the embodiment of FIG. 7 was embossed with a non-heated embossing roll.

[0147] In the case of the embodiment of FIG. 8, the top ply 1 has been embossed by a heated embossing roll that was heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°. The bottom ply 2 of the embodiment of FIG. 8 was embossed with a non-heated embossing roll.

[0148] Both the top ply 1 and the bottom ply 2 of the embodiment of FIG. 9 were embossed by respective heated embossing rolls that were heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 160°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°.

[0149] Each of the tissue paper products of FIGS. 7, 8, and 9 has particularly good absorption properties, a large thickness (as compared to conventional products with a similar strength), and a high (tensile) strength (as compared to conventional products with a similar thickness). Specifically, the tissue paper products of FIGS. 7, 8, and 9 have a good wetness shape memory, i.e., the embossments disappear less than in comparable conventional products when the product has been wet.

[0150] The embodiments of FIGS. 10, 11, and 12 differ from those of FIGS. 7, 8, and 9, for example, in that they all have one inner ply 3, and a bottom ply 20 that has been embossed together with another ply 21. Also the basis weight of the embodiments of FIGS. 10, 11, and 12 is in each case in a range of 30 to 150 g/m.sup.2. The inner ply 3 is in each case unembossed at least in the sense of not having been embossed prior to the final ply-bonding having taken place.

[0151] All four plies of each of the embodiments of FIGS. 10, 11, and 12 are made of Conventional Wet Press (CWP) paper.

[0152] The top ply 1, 10 of each of the embodiments of FIGS. 10, 11, and 12 is embossed with two types of embossments with different heights. The bottom ply 2 is in each case embossed with one type of embossments. In each case, the four plies are ply-bonded, for example, using an adhesive applied to the side of the inner ply 3 facing the ply 21. However, according to other embodiments, the adhesive may, e.g., be applied to tips of the higher embossments of the top ply 1 and/or to tips of embossments of the bottom ply 20, 20′, 21, 2′, etc. (in addition to or alterative to the application to the inner ply 3).

[0153] In the case of the embodiment of FIG. 10, the bottom ply 20 and an another ply 21 have been embossed together by a heated embossing roll that was heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°. The top ply 1 of the embodiment of FIG. 10 was embossed with a non-heated embossing roll.

[0154] In the case of the embodiment of FIG. 11, the top ply 1 has been embossed by a heated embossing roll that was heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°. The bottom ply 20 and an another ply 21 of the embodiment of FIG. 11 have been embossed by a non-heated embossing roll.

[0155] Both the top ply 1 as well as bottom ply 20 and (together with the bottom ply 20) the another ply 21 of the embodiment of FIG. 12 have been embossed by respective heated embossing rolls that were heated to a temperature in the range of 80° C. to 170°, optionally 100° C. to 165°, 110° C. to 165°, 120° C. to 160°, or 130° C. to 155°.

[0156] Each of the tissue paper products of FIGS. 10, 11, and 12 has particularly good absorption properties, a large thickness (as compared to conventional products with a similar strength), and a high (tensile) strength (as compared to conventional products with a similar thickness). Specifically, the tissue paper products of FIGS. 10, 11, and 12 have a good wetness shape memory, i.e., the embossments disappear less than in comparable conventional products when the product has been wet.

[0157] For each of the embodiments of FIGS. 4 to 12, the density of the micro-embossments on the outermost plies are provided in a density which lies in a range of 25 to 120 dots/cm.sup.2.

[0158] Moreover, each of the tissue paper products of FIGS. 4 to 12 has particularly good absorption properties, a large thickness (as compared to conventional products with a similar strength), and a high (tensile) strength (as compared to conventional products with a similar thickness). Specifically, the tissue paper products of FIGS. 4 to 12 a good wetness shape memory, i.e., the embossments disappear less than in comparable conventional products when the product has been wet.

EXPERIMENTAL RESULTS

[0159] In the following, experimental examples of embodiments (examples) in accordance with the present disclosure will be compared with conventional tissue paper products.

EXAMPLE SERIES 1

[0160] Tissue paper product with three plies made of Conventional Wet Press (CWP) paper in accordance with the present disclosure were compared to conventional tissue paper products comprising three plies made of Conventional Wet Press (CWP) paper. For both products, a total grammage of the tissue paper product was around 53.5 g/m.sup.2.

[0161] The top ply was double-height embossed, wherein a part comprising micro-embossments was provided with the micro- embossments at a density of 50 dots/cm.sup.2. The double-height embossments covered about 3.7% of the surface area of the top ply. The middle play was flat (i.e., unembossed prior to final ply-bonding, that is, not pre-embossed). The bottom ply was provided with micro-embossments at a density of 43 dots/cm.sup.2.

[0162] In each case, a roll of the tissue paper product with a diameter of 120 mm was produced. The roll length was adapted according to thickness variations so that the roll firmness of different products was about the same. The top ply was embossed with a double height embossing design, the inner ply remained flat (no pre-embossing on the inner ply). The bottom ply was embossed with a micro-embossing design.

[0163] For the tissue paper products in accordance with the present embodiments, a micro-embossing design with a density of 43 d/cm.sup.2 (d/cm.sup.2 stands for dots per square centimeter) was used. For the reference products, a two micro-embossing designs with densities of 51 d/cm.sup.2 and 43 d/cm.sup.2 were used. No water was added to the inner ply. The manufacturing speed for the products was chosen both for examples in accordance with the present disclosure as well as reference examples to be at 100 m/min.

Results

[0164] The tissue paper products produced using a heated embossing roll have a larger thickness even at lower embossing load as compared to the reference examples. This is illustrated in the following graph:

[0165] The products in accordance with the present disclosure are illustrated in the graph with triangles. The comparative products are illustrated with circular and diamond shapes. The impact of heating the embossing roll on the CD tensile is shown in the following graph. It shows that the CD tensile remains in the same range (216-222 N/m), whereas the thickness increases by up to 15% (from 0.61 mm to 0.70 mm). The CD tensile appears to drop only for a higher thickness increase:

[0166] The impact of heating the embossing roll on the MD tensile is shown in the following graph (“MDT” on the y-axis stands for main direction tensile strength). The graph shows that MD tensile increases with heating, in comparison to the reference products, whereas the thickness increases by up to 15% (from 0.61 mm to 0.70 mm):

[0167] The impact of heating the embossing roll on the absorption (in g/g) is shown in the next graph (“CDT” on the y-axis stands for cross direction tensile strength). It shows that the absorption increases with heating. The higher the thickness, the higher the absorption:

EXAMPLE SERIES 2

[0168] Tissue paper products comprising three plies of CWP and a total grammage of around 50 g/m.sup.2 were compared. A roll of diameter 120 mm was produced. The roll length was adapted according to thickness variations so that the roll firmness of different products was about the same. The top ply was embossed with a double height embossing design, wherein a part comprising micro-embossments was provided with the micro-embossments at a density of 50 dots/cm.sup.2. The double-height embossments covered about 4.5% of the surface area of the top ply. The inner ply remained flat. The bottom ply was embossed with a micro-embossing design having 50 d/cm.sup.2. Trials were carried out with reference products (no addition of water and no heating of the micro-embossing roll) and products in accordance with the present disclosure (addition of 1.0 g/m.sup.2 of water on the bottom ply with a Weko unit and micro-embossing of this ply with a heated roller). Trials were carried out at a processing speed of 650 m/min.

Results

[0169] The following graphs show the variation of CD and MD tensile strength when the thickness of the tissue paper product is increased. Surprisingly, when using the heated embossing roll to produce the tissue paper product, when thickness increases by 16% vs. the reference product, the CD tensile strength is still higher than the one of the reference product (and when thickness is increased by 20% the MD tensile is still higher than the reference value):

Comparative Examples Using Products With Two Plies

[0170] Comparisons were also made between bathroom tissue products with two plies that were either made with or without using a heated embossing roll, and with a random nested structure (nesting of embossments, without, however, synchronizing the rolls to create a systematic nested structure), to identify whether the use of a heated embossing roll would allow increasing the thickness of tissue paper products.

Results

[0171] A decrease of the tensile strength was perceived, as soon as the thickness increase exceeded about 5%. The example below shows results from trials performed with a 2-ply bathroom towel with a grammage of 33 g/m.sup.2. The top ply was embossed with a double height embossing design, the bottom ply was embossed with a micro-embossing design having 43d/cm.sup.2. For the reference trial, this roll was not heated, whereas for the trials with a heated roll, the sheet was pre-moistened with 1.0 g/m.sup.2, and then embossed with the heated micro-embossing roller.

[0172] From these findings, it may be concluded that the desirable properties relating to increased thickness, high tensile strength, and good absorption, manifest themselves mostly in tissue paper products comprising at least three plies and having an unembossed inner ply.

EXAMPLE SERIES 3

[0173] Comparisons were made between tissue paper products produced with a bottom ply produced either using a heated embossing roll or a non-heated roll, as well as either comprising a flat inner ply (unembossed prior to final ply-bonding) made of Conventional Wet Press (CWP) paper (and referred to as “Standard” in the following) or a creped ribbed inner ply, i.e., a ply produced using a creping blade provided with a rake edge comprising indentations. Those inner plies were combined with two outer plies of the same quality and are in the following referred to as “Trio”.

[0174] The exemplary products as well as the reference products were made with three plies of Conventional Wet Press (CWP) paper with a total grammage of around 53.5 g/m.sup.2.

[0175] The top ply was embossed with a density of 50 dots/cm.sup.2 and with double-height embossments covering about 3.7% of the surface area of the top ply. The middle play was provided with a creped ribbed structure. The number of peaks in a cross direction associated with ribs and valleys amounted to about 9 peaks per cm, and the core roughness (Rk value) in the cross direction was 70.7 μm. The bottom ply was heat-embossed with an embossment density of 43 dots/cm.sup.2.

[0176] Core Roughness Rk, as referred to here, is defined according to ISO 13565-1 and ISO 13565-2. The roughness profile as per ISO 13565-1 is generated by a special filtering technique minimizing profile distortions due to deep valleys in plateau profiles. A straight line divides the Abbott-Firestone curve (See FIG. 2) into three areas from which the parameters are then computed as per ISO 13565-2. Core roughness depth Rk is the depth of the roughness core profile. In other words, it is the core height of the profile along the Y-axis of the Abbott-Firestone curve generated by placing a 40% line on the curve at the minimum slope point and extending the lines to the 0% and the 100% points.

[0177] A roll with a diameter of 120 mm was produced, and the roll length have been adapted according to thickness variations so that the roll firmness remained the same.

[0178] Two different plies were used for the inner ply: a standard paper (denoted as the “Reference” in the following) and a paper produced according to a creping process using a creping blade with a rake edge provided with indentations.

[0179] Moreover, some products were made using non-pre-moistened and non-heated embossing rolls for the bottom ply, and some products were made using pre-moistening and embossing with a heated roll for bottom ply. The thicknesses of the products were measured.

Results

[0180] It was found that the creped ribbed ply allows further increasing the thickness of the products (of both those with an inner ply produced without pre-moistening and without using a non-heated embossing roll, as well as of those with an inner ply produced with pre-moistening and embossing with a heated embossing roll).

TABLE-US-00001 Heating + pre- Thickness moistening (1 sheet) Trio off 0.61 Reference Trio Trio off 0.63 Creped ribbed ply Trio Trio on 0.71 Reference Trio Trio on 0.73 Creped ribbed ply Trio

EXAMPLE SERIES 4

[0181] Another study was performed on the basis of tissue paper products with three plies made of Conventional Wet Press (CWP) paper and a total grammage of around 53.5 g/m.sup.2. A roll with a diameter of 120 mm was produced, and the roll length was adapted according to thickness variations so that the roll firmness remained the same.

[0182] Comparisons were made between products obtained using the following alternative manufacturing conditions: [0183] Double-height embossing of top and inner ply: The top and the inner ply were embossed together with a double height embossing design. Micro-embossments were provided at a density of 50 dots/cm.sup.2 and the double-height embossments covered about 3.7% of the surface area. As an alternative, products were made with a flat inner ply (an inner ply that was not pre-embossed). The bottom ply was embossed with a micro-embossing design (density 43 d/cm.sup.2), and the three plies were bonded together with a random nested structure; and [0184] Double-height embossing of top ply, flat inner ply: The top ply was embossed with a double height embossing design, the inner ply remained flat. The bottom ply was embossed with a micro-embossing design (density 43 d/cm.sup.2).

[0185] For each of the two processes, the bottom embossing was either performed with a non-heated roll (referred to as the “reference” condition) or with a heated roll, wherein the bottom ply was pre-moistened prior to the heat-embossing. Several trials were run to produce the various products, using different embossing loads for the bottom ply (the top plies were always embossed using the same load). All of the products were manufactured at a processing speed of 200 m/min.

[0186] Results

[0187] The following graph show the obtained product thickness being in function of the embossing load:

[0188] The graph compares the thicknesses of products with a flat inner ply produced without a heated embossing roll with products with a flat inner ply and manufactured using heat-embossing, as well as products with a random nested structure produced using a non-heated embossing roll with products with a random nested structure produced manufactured using a heated embossing roll in function of the embossing load. The thickness of products with a flat inner ply, when manufactured using the same embossing load, is substantively increased by using a heated embossing roll. Similarly, the thickness of products with a random nested structure is significantly increased with respect to the reference product manufactured with the same embossing load. The products with a random nested structure manufactured with a heated embossing roll achieve similar thicknesses at the same embossing load as products with a flat inner ply but manufactured without heat-embossing. Thus, the benefit of heat-embossing may be particularly high for manufacturing products with a flat inner ply.

[0189] The next graph illustrates results regarding the tensile strength (Cross Direction (CD) tensile strength):

[0190] The products with a random nested structure and manufactured using heat-embossing performed similarly as products with a flat inner ply that were manufactured without heat-embossing: roughly the same CD tensile strength was achieved for equal thickness, and for the higher thickness reached with a flat inner ply and using heated embossing during manufacturing, the curve slope is equivalent or slightly higher for products with a flat inner ply as opposed to those with a random nested structure. The products with a flat inner ply and manufactured using a heated embossing roll performed better than those also manufactured using a heated embossing roll, but having a random nested structure (i.e., the embossments of the inner ply are nested randomly in the embossments of one of the outer plies): the CD tensile strength was higher for same thickness, with a gain of about 20%), and the CD tensile strength of the products with a flat inner ply and manufactured using a heated embossing roll was higher than the one of the products manufactured using a heated embossing roll, but having a random nested structure, when comparing products with equal thicknesses.

[0191] It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed devices and systems without departing from the scope of the disclosure. Other aspects of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the features disclosed herein. It is intended that the specification and examples be considered as exemplary only. Many additional variations and modifications are possible and are understood to fall within the framework of the disclosure.