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

Abstract

Disclosed is a tissue paper product, including between two and four plies, including at least a first ply and a second ply, the two plies, three plies, or four plies being ply-bonded, to form the tissue paper product, the first ply and the second ply being the outermost plies of the tissue paper product, a grammage of the tissue paper product being in a range of 24 to 50 g/m.sup.2 if a total number of plies of the tissue paper product is 2, in a range of 34 to 65 g/m.sup.2 if a total number of plies of the tissue paper product is 3, and in a range of 55 to 95 g/m.sup.2 if a total number of plies of the tissue paper product is 4, the first ply being a structured paper ply.

Claims

1. A tissue paper product, such as toilet paper or household towel, wherein the tissue paper product comprises between two and four plies, including at least a first ply and a second ply, the two plies, three plies, or four plies being ply-bonded, optionally using an adhesive such as lamination glue or mechanical bonding, such as edge embossing, to form the tissue paper product, the first ply and the second ply being outermost plies of the tissue paper product, a grammage of the tissue paper product being in a range of 24 to 50 g/m.sup.2 if a total number of plies of the tissue paper product is 2, in a range of 34 to 65 g/m.sup.2 if a total number of plies of the tissue paper product is 3, and in a range of 55 to 95 g/m.sup.2 if a total number of plies of the tissue paper product is 4, and wherein the first ply is a structured paper ply, such as a ply made of TAD, UCTAD, eTAD, Atmos, or NTT, and the first ply has been embossed with a heated first embossing roll.

2. The tissue paper product of claim 1, wherein the first ply comprises micro-embossments with a micro-embossment height in a range of 0.1 mm to 1.2 mm.

3. The tissue paper product of claim 1, wherein the first ply comprises macro-embossments with a macro-embossment height in a range of 0.2 mm to 2.0 mm, optionally 0.8 mm to 1.4 mm, wherein, optionally, the macro-embossments cover between 1% and 20% of a total surface of the first ply, optionally between 2% and 10%, or between 3% and 6%.

4. The tissue paper product of claim 1, wherein the first ply has been embossed with a heated embossing roll 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°.

5. The tissue paper product of claim 1, wherein the first ply has been moistened, prior to the step of embossing the first ply, with a liquid, such as water optionally provided with one or several additives, with an amount of liquid being 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.

6. The tissue paper product of claim 1, wherein the first ply has not been moistened with a liquid prior to the step of embossing.

7. The tissue paper product of claim 1, wherein the second ply is made of Conventional Wet Press paper (CWP) or is a structured paper ply, such as a ply made of TAD, UCTAD, eTAD, Atmos, or NTT.

8. The tissue paper product of claim 7, wherein the second ply has been embossed with a heated second embossing roll.

9. The tissue paper product of claim 1, wherein the tissue paper product comprises exactly two plies, being the first ply and the second ply, wherein the first ply comprises first embossments with a first height (h1), the first height (h1) being in a range of 0.2 mm to 2.0 mm, the adhesive, such as lamination glue, is optionally applied to tips of the first embossments of the first ply, the second ply comprises second embossments with a second height (h2), the second height (h2) being in a range of 0.2 mm to 2.0 mm, the first ply optionally comprises third embossments with a third height (h3) smaller than the first height (h1) (h1>h3), and the second ply optionally comprises fourth embossments with a fourth height (h4) smaller than the second height (h2) (h2>h4).

10. The tissue paper product of claim 1, wherein the tissue paper product comprises exactly three plies, being the first ply and the second ply and a third ply, located between the first ply and the second ply, the second ply optionally being made of Conventional Wet Press (CWP) paper and/or the third ply optionally being made of Conventional Wet Press (CWP) paper, the first ply comprises first embossments with a first height (h1), the first height (h1) being in a range of 0.2 mm to 2.0 mm, the adhesive, such as lamination glue, is optionally applied to parts of the third ply bonded to tips of the first embossments of the first ply, the second ply comprises second embossments with a second height (h2), the second height (h2) being in a range of 0.2 mm to 2.0 mm, the first ply, optionally, comprises third embossments with a third height (h3) smaller than the first height (h1) (h1>h3), and the second ply, optionally, comprises fourth embossments with a fourth height (h4) smaller than the second height (h2) (h2>h4).

11. The tissue paper product of claim 10, wherein the third ply has not been embossed prior to ply-bonding.

12. The tissue paper product of claim 10, wherein the second ply and the third ply have been embossed together to form the second embossments on the second ply and the third ply, and wherein, optionally, the second ply and the third ply have been embossed together to form also the fourth embossments on the second ply and the third ply.

13. The tissue paper product of claim 1, wherein the tissue paper product comprises exactly four plies, being the first ply and the second ply, and a third ply and a fourth ply located between the first ply and the second ply, the second ply and/or third ply and/or the fourth ply optionally being made of Conventional Wet Press (CWP) paper, wherein the first ply comprises first embossments with a first height (h1), the first height (h1) being in a range of 0.2 mm to 2.0 mm, the adhesive, such as lamination glue, is optionally applied to parts of the third ply bonded to tips of the first embossments of the first ply, the second ply comprises second embossments with a second height (h2), the second height (h2) being in a range of 0.2 mm to 2.0 mm, the first ply optionally comprises third embossments with a third height (h3) smaller than the first height (h1) (h1>h3), and the second ply optionally comprises fourth embossments with a fourth height (h4) smaller than the second height (h2) (h2>h4).

14. The tissue paper product of claim 13, wherein the second ply and the fourth ply have been embossed together to form the second embossments on the second ply and the fourth ply, wherein the third ply has not been embossed prior to ply-bonding or has been embossed separately from the first ply, the second ply, and the fourth ply, and the fourth embossments have, optionally, been formed only on the second ply but not on the fourth ply, or the second ply and fourth ply have, optionally, been embossed together to form also the fourth embossments on the second ply and the fourth ply.

15. The tissue paper product of claim 13, wherein the second ply, the third ply, and the fourth ply have been embossed together to form the second embossments on the second ply, the third ply, and the fourth ply, and, optionally, the second ply, the third ply, and the fourth ply have been embossed together to form the fourth embossments on the second ply, the third ply, and the fourth ply, or, optionally, the fourth embossments have been formed on the second ply and the fourth ply, but not on the third ply, or, optionally, the fourth embossments have been formed on the second ply, but not on the third ply and the fourth ply.

16. The tissue paper product of claim 13, wherein the third ply and the fourth ply have been embossed together separately from the first ply and the second ply, or wherein the third ply and the fourth ply are unembossed.

17. The tissue paper product of claim 9, wherein the first embossments are provided on an area constituting between 1% and 20% of a total surface of the first ply, and/or a density of the third embossments is in a range of 25 to 120 embossments/cm.sup.2, optionally 40 to 100 embossments/cm.sup.2, or 50 to 80 embossments/cm.sup.2.

18. The tissue paper product of claim 9, wherein the second embossments are provided on an area constituting between 1% and 20% of a total surface of the second ply, and/or a density of the fourth embossments is in a range of 25 to 120 embossments/cm.sup.2, optionally 40 to 100 embossments/cm.sup.2, or 50 to 80 embossments/cm.sup.2.

19. The tissue paper product of claim 1, wherein a grammage of each of the plies is in a 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.

20. A tissue paper product, such as toilet paper or household towel, wherein the tissue paper product comprises between two and four plies, including at least a first ply and a second ply, the two plies, three plies, or four plies being ply-bonded, optionally using an adhesive such as lamination glue or mechanical bonding, such as edge embossing, to form the tissue paper product, the first ply and the second ply being the outermost plies of the tissue paper product, a grammage of each of the plies being in a 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, and wherein the first ply is a structured paper ply, such as a ply made of TAD, UCTAD, eTAD, Atmos, or NTT, and the first ply has been embossed with a heated embossing roll.

21. 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.

22. The roll of tissue paper product of claim 21, wherein a diameter of the roll is in a range of from 85 to 200 mm.

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

24-42. (canceled)

43. A roll of tissue paper product made of a spirally wound continuous web of the tissue paper product of claim 20, 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.

44. The roll of tissue paper product of claim 43, wherein a diameter of the roll is in a range of from 85 to 200 mm.

45. A stack of unfolded sheets or of folded sheets, optionally of interfolded sheets, made of the tissue paper product of claim 20.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0168] 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:

[0169] The description is given with reference to the accompanying drawings, in which:

[0170] FIGS. 1 to 7 are sectional views of embodiments of a tissue paper product in accordance with the present disclosure, each of which comprises two plies;

[0171] FIGS. 8 to 18 are sectional views of embodiments of a tissue paper product in accordance with the present disclosure, each of which comprises three plies; and

[0172] FIG. 19 depicts a manufacturing apparatus with which embodiments of the method of manufacturing a tissue paper product in accordance with the present disclosure is carried out.

[0173] The embodiments of a tissue paper product of FIGS. 1 to 7 comprise two plies: a top ply 1, 1′ 1*, 1*′ and a bottom ply 2, 2′, 2*, 2*′. Regarding the nomenclature: The apostrophe indicates that the ply has been heat-embossed. The asterisk indicates that the ply is a structured paper ply. For example: “1” stands for a CWP top ply that was not heat-embossed. “1′” stands for a heat-embossed CWP top ply. “1*” stands for a structured paper top ply that was not heat-embossed. “1*′” stands for a heat-embossed structured paper top ply. This nomenclature is used throughout the descriptions accompanying FIGS. 1 to 15. Moreover, a heat-embossed ply is illustrated with a slightly thicker lines in the figures than a non-heat embossed counter-part. A structured ply is illustrated using a dashed line, whereas a CWP ply is illustrated using a regular line.

[0174] In the case of all of the embodiments of FIGS. 1 to 7, the top ply has been double-height embossed, i.e., it comprises two types of embossments with different heights. The bottom ply has been all cases been embossed with one type of embossments. The embossing is here referred to as a pre-embossing, i.e., an embossing prior to the final bonding having been carried out.

[0175] In the case of all embodiments of FIGS. 1 to 7, the top ply and the bottom ply have been ply-bonded. An example of where the respective plies are ply-bonded is shown as the respective region 4. The two plies have been ply-bonded using an adhesive (lamination glue). However, according to other embodiments, the ply-bonding could, e.g., have been effected using mechanical bonding such as edge embossing.

[0176] The top ply 1* of FIG. 1 is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT. The top ply 1* has been embossed with a non-heated embossing roll.

[0177] The bottom ply 2*′ of FIG. 1 is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT and has been embossed with a heated embossing roll. It is thus an example of a “first ply” in the sense of the present application. In other words, the first ply is in the case of the embodiment of FIG. 1 the bottom ply. The top ply of

[0178] FIG. 1 is a “second ply” in the sense of the present application. The bottom ply 2*′ has been embossed with a heated first embossing roll heated to a temperature in the range of 80° C. to 170°. It is illustrated with a thickened line, in order to illustrate that it has been heat-embossed.

[0179] The embodiment of FIG. 2 differs from the one of FIG. 1 in that the top ply 1*′ of FIG. 2 is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT that has been heat-embossed using a heated embossing roll, i.e., with a heated first embossing roll heated to a temperature in the range of 80° C. to 170°. It is illustrated with a thickened line, in order to illustrate that it has been heat-embossed. The bottom ply 2* of FIG. 2 is also a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT. However, the bottom ply 2* has been embossed with a non-heated embossing roll.

[0180] The embodiment of FIG. 3 comprises both a top ply 1*′ that is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT which has been heat-embossed using a heated embossing roll, i.e., with a heated first embossing roll heated to a temperature in the range of 80° C. to 170°, as well as a bottom ply 2*′ that is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT which has been heat-embossed using a heated embossing roll, i.e., with a heated second embossing roll heated to a temperature in the range of 80° C. to 170°.

[0181] Whereas the embodiments of FIGS. 1 to 3 comprise both a structured paper ply as a top ply as well as a structured paper ply as a bottom ply, the embodiments of FIGS. 4 to 7 comprise a structured ply as well as a CWP ply.

[0182] The embodiment of FIG. 4 comprises a top ply 1 that is made of Conventional Wet Press (CWP) paper which has been embossed using a non-heated embossing roll. It further comprises a bottom ply 2*′ that is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT which has been heat-embossed using a heated embossing roll, i.e., with a heated embossing roll heated to a temperature in the range of 80° C. to 170°.

[0183] The embodiment of FIG. 5 comprises a top ply 1*′ that is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT which has been heat-embossed using a heated embossing roll, i.e., with a heated first embossing roll heated to a temperature in the range of 80° C. to 170°. It further comprises a bottom ply 2*′ made of Conventional Wet Press (CWP) paper which has been embossed using a non-heated embossing roll.

[0184] The embodiment of FIG. 6 comprises a top ply 1′ that is made of Conventional Wet Press (CWP) paper which has been heat-embossed using a heated embossing roll, i.e., with a heated embossing roll heated to a temperature in the range of 80° C. to 170°. It further comprises a bottom ply 2*′ that is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT which has been heat-embossed using a heated embossing roll, i.e., with a heated first embossing roll heated to a temperature in the range of 80° C. to 170°.

[0185] The embodiment of FIG. 5 comprises a top ply 1*′ that is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT which has been heat-embossed using a heated first embossing roll, i.e., with a heated embossing roll heated to a temperature in the range of 80° C. to 170°. It further comprises a bottom ply 2*′ made of Conventional Wet Press (CWP) paper which has been heat-embossed using a heated embossing roll, i.e., with a heated embossing roll heated to a temperature in the range of 80° C. to 170°.

[0186] A grammage of the tissue paper products of FIGS. 1 to 7 is in a range of 24 to 50 g/m.sup.2, respectively.

[0187] The embodiments of FIGS. 8 to 15 are embodiments comprising exactly three plies.

[0188] The top ply 1* of the embodiment of FIG. 3 is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT. It was embossed using a heated first embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°. The middle ply 3 of FIG. 8 is a ply made of Conventional Wet Press (CWP) paper and it was not pre-embossed (prior to the final ply-bonding). The bottom ply 2 of the embodiment of FIG. 8 is a ply made of Conventional Wet Press (CWP) paper. It was embossed using a non-heated embossing roll.

[0189] The top ply 1 of the embodiment of FIG. 9 is a ply made of Conventional Wet Press (CWP) paper. It was embossed using a non-heated embossing roll. The middle ply 3 of FIG. 9 is another ply made of Conventional Wet Press (CWP) paper and it was not pre-embossed (prior to the final ply-bonding). The bottom ply 2*′ of the embodiment of FIG. 9 is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT. It was heat-embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°.

[0190] In the case of the embodiment of FIG. 10, the top ply 10 and the neighboring ply 11 are both made of Conventional Wet Press (CWP) paper and have been double-height embossed together using a non-heated embossing roll. The bottom ply 2*′ of FIG. 10 is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT. It was embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°.

[0191] In the case of the embodiment of FIG. 11, the top ply 1*′ is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT, that was embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°. The bottom ply 20 and the neighboring ply 21 are both made of Conventional Wet Press (CWP) paper and have been double-height embossed together using a non-heated embossing roll.

[0192] The embodiment of FIG. 12 comprises a top ply 1*′ that is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT, that was embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°. The middle ply 3 of FIG. 12 is another ply made of Conventional Wet Press (CWP) paper and it was not pre-embossed (prior to the final ply-bonding). The bottom ply 2′ of the embodiment of FIG. 12 is made of Conventional Wet Press (CWP) paper and has been heat-embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°.

[0193] The embodiment of FIG. 13 comprises a top ply 1′ made of Conventional Wet Press (CWP) paper and has been heat-embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°. The middle ply 3 of FIG. 12 is another ply made of Conventional Wet Press (CWP) paper and it was not pre-embossed (prior to the final ply-bonding). The bottom ply 2*′ of the embodiment of FIG. 12 is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT, that was embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°.

[0194] In the case of the embodiment of FIG. 14, the top ply 10′ and the neighboring ply 11′ are both made of Conventional Wet Press (CWP) paper and have been double-height heat-embossed together using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°.The bottom ply 2*′ of FIG. 10 is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT. It was embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°.

[0195] In the case of the embodiment of FIG. 15, the top ply 1*′ is a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT, that was embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°. The bottom ply 20′ and the neighboring ply 21′ are both made of Conventional Wet Press (CWP) paper and have been double-height heat-embossed together using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°.

[0196] FIGS. 16 to 18 depict embodiments with a middle ply 3 made of CWP, a top ply 1*, 1*′ being a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT, and a bottom ply 2*, 2*′ being a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT.

[0197] In the case of the embodiment of FIG. 16, the top ply 1* was embossed using a non-heated embossing roll, whereas the bottom ply 2*′ was heat-embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°.

[0198] In the case of the embodiment of FIG. 17, the top ply 1*′ was heat-embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°, whereas the bottom ply 2* was embossed using a non-heated embossing roll.

[0199] Moreover, the embodiment of FIG. 18 comprises a top ply 1*′ that was heat-embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°, as well as a bottom ply 2*′ that was heat-embossed using a heated embossing roll, i.e., an embossing roll heated to a (steady-state) temperature in the range of 80° C. to 170°.

[0200] The grammage of the tissue paper products of FIGS. 8 to 18 is in a range of 34 to 65 g/m.sup.2.

[0201] FIG. 19 is a schematic representation of (a part of) and embodiment of a manufacturing apparatus for manufacturing a tissue paper product in accordance with the present disclosure using an embodiment of a method in accordance with the present disclosure. In the following, it will be described how an embodiment of the method is carried out using the apparatus illustrated in FIG. 19.

[0202] A first ply 15 made of Conventional Wet Press (CWP) paper is provided. It is unwound from a first unwinding roll 210. A second ply 25, being a structured paper ply made of TAD, UCTAD, eTAD, Atmos, or NTT, is provided. It is unwound from a second unwinding roll 220.

[0203] The structured paper ply 25 is moistened in a wetting unit 150 with water and then heat-embossed between an embossing roll 50 and a counter roll 60. The heatable embossing roll 50 is heated to a steady-state temperature in the range of 80° C. to 170° C.

[0204] The CWP paper ply 15 is embossed between a non-heatable embossing roll 40 and a counter roll 35. It is also provided with adhesive using a transfer roll 80.

[0205] The CWP ply 15 and the heat-embossed structured paper ply 25 are then ply-bonded between the embossing roll 40 and a marrying roll 70. The two-ply tissue paper product 110 is then wound-up on the winding roll 300.

[0206] Each of the tissue paper products of FIGS. 1 to 18 as well as the ones manufactured using the apparatus of FIG. 19 have a high 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). Specifically, the tissue paper products have a good wetness shape memory, i.e., the embossments disappear less than in comparable conventional products when the product has been wet.

EXPERIMENTAL RESULTS

[0207] In the following, experimental examples of embodiments (examples) in accordance with the present disclosure will be compared with conventional tissue paper products.

[0208] In order to evaluate the performance of tissue paper products in accordance with the present disclosure (manufactured in accordance with the method in accordance with the present disclosure), several reference products were manufactured. The reference products were manufactured without using any heat-embossing, i.e., without embossing a ply using a heated embossing roll.

Reference Products A

[0209] To acquire first reference measurements (“reference products A”), two structured TAD plies with a grammage of about 20 g/m.sup.2 were investigated.

Reference Product B

[0210] A reference product B was manufactured with two structured TAD plies. Both structured paper plies made of TAD were provided with a grammage of about 20 g/m.sup.2. The top ply was embossed with a single height embossing design. The bottom ply was not pre-embossed, but instead conveyed to the main embossing station, where the top ply and the bottom ply were ply-bonded together using glue at tips of the embossments of the top ply.

Reference Product C

[0211] Reference product C was manufactured almost identically to reference product B. The difference is that the bottom ply was pre-embossed with micro-embossments, that is, embossments with a height in a range of 0.1 mm to 1.2 mm. The embossment density of the micro-embossments was 43 embossments/cm.sup.2.

[0212] For none of the reference products A, B, and C, a step of moistening any ply prior to embossing it or any heated embossing roll was used.

Exemplary Product 1

[0213] Exemplary product 1 was manufactured using an embodiment of the method in accordance with the present disclosure and constitutes a tissue paper product in accordance with the present disclosure.

[0214] Exemplary product 1 comprises two structured TAD plies. The top ply was embossed with a single height embossing design (using a non-heated embossing roll). The bottom ply was pre-moistened using water, micro-embossed with a heated embossing roller (heated to a steady state temperature in a range of 80° C. to 170° C., and then ply-bonded together with the top ply using glue at tips of the embossments of the top ply.

Exemplary Product 2

[0215] Exemplary Product 2 was manufactured analogously as Exemplary Product 1, but the embossing load on the bottom ply was increased.

Exemplary Product 3

[0216] Exemplary Product 3 was manufactured analogously as Exemplary Product 2, but the step of pre-moistening the bottom ply prior to the heat-embossing was omitted.

[0217] The following table summarizes the manufacturing settings for the various Reference Products and Exemplary Products, as well as measurement results for the basis weight (grammage), the thickness, the main directional tensile strength (MDT), the cross directional tensile strength (CDT), the softness, as well as the absorption capacity.

TABLE-US-00001 Embossing load Basis Thickness MD CD Heat- Pre- bottom ply weight (1 sheet) Tensile Tensile Softness Absorption Product embossing moistening (kg/cml) (g/m.sup.2) mm (N/m) (N/m) Panel (g/g) Ref A N N — 38.1 0.53 229 101 12.4 Ref B N N — 37.6 0.49 268 132 1.5 12.5 Ref C N N 46 36.3 0.53 172  77 1.6 12.5 Ex. 1 Y Y 20 36.6 0.53 247 114 1.5 12.0 Ex. 2 Y Y 42 36.6 0.62 192  94 1.5 13.2 Ex. 3 Y N 43 36.7 0.62 184  87 1.5 13.2

[0218] As the table illustrates, the reference product B (without embossing of the bottom ply) has a lower thickness than reference product A. This is due to the tension required to convey the plies in the converting line. However, reference product B has higher CD and MD tensile strengths than reference product A, respectively. This can be attributed to the lamination glue.

[0219] Reference product C (with a micro-embossed bottom ply) has the same thickness as reference product A. An explanation therefore is that the micro-embossing performed on the bottom ply compensates for the loss of thickness due to the tension. However, reference product C has a lower tensile strength than reference product A, due to the mechanical impact of the embossing.

[0220] The exemplary products, manufactured using heat-embossing, can either keep the same thickness as a tissue paper product made of two structured TAD plies (but without heat-embossing), while having a higher tensile strength (see the comparison between reference product A and exemplary product 1 in the table), or the thickness can be increased as compared to the reference product C (with a micro-embossed bottom ply), without losing any tensile strength (see the comparison between reference product C and exemplary product 2 in the table). Another benefit associated with the technology of heat-embossing the bottom structured TAD ply is that the properties of the resulting tissue paper product can be adjusted by adjusting the embossing load of the embossing unit with the heatable embossing roll(s). This way, the tissue paper product can be easily tailored to requirements such as higher tensile strength or larger thickness, etc.

[0221] The following graphs shows experimental results for the CD tensile strength and the MD tensile strength, comparing reference products A, B, and C with exemplary products 1 and 2.

[0222] The following graph compares the softness of exemplary products 1 and 2 and of the reference products A, B, and C.

[0223] This graph shows that the softness can be maintained (in comparison to reference products) when relying on heat-embossing the structured TAD ply, while the thickness can be increased.

[0224] When comparing the absorption capacity (in g of water per g of cellulose) of the exemplary products 1 and 2 and of the reference products A, B, and C, one finds that the absorption capacity can be increased with an increase of thickness for the products manufactured relying on heat-embossing.

[0225] Moreover, the properties of exemplary product 3 are very similar to those of exemplary product 2 (see the table including experimental data included above). Thus, also without a step of moistening being applied to the bottom ply prior to heat-embossing, the discussed benefits are obtained in tissue paper products in accordance with the present disclosure.

[0226] 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.