TISSUE PAPER MATERIAL AND TISSUE PAPER PRODUCT

Abstract

The present disclosure relates to a single-ply tissue paper material having a basis weight less than 40 gsm and a GMT tensile strength of at least 60 N/m. comprising a non-wood tissue ply. comprising non-wood cellulose pulp fibres being present in an amount of at least 10% by dry weight of the of the non-wood tissue ply. The disclosure also relates to a single-ply tissue paper product and to a multi-ply tissue paper product comprising at least one non-wood tissue ply.

Claims

1. A single-ply tissue paper material having a basis weight less than 40 gsm and a GMT tensile strength of at least 60 N/m, comprising a non-wood tissue ply, said non-wood tissue ply comprising non-wood cellulose pulp fibres in an amount of at least 10% by dry weight of the of the non-wood tissue ply.

2. The single-ply tissue paper material according claim 1, wherein the tissue paper material has a GMT tensile strength of at least 70 N/m.

3. The single-ply tissue paper material according claim 1, wherein the tissue paper material has a GMT tensile strength of at least 80 N/m.

4. The single-ply tissue paper material according to claim 1, having a basis weight of less than 30 gsm.

5. The single-ply tissue paper material according to claim 1, having a basis weight of less than 25 gsm.

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22. (canceled)

23. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose pulp fibres contains at least 15% hemicellulose.

24. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose pulp fibres contains no more than 15% lignin.

25. The single-ply tissue paper material, a single-ply tissue paper product or a multi-ply tissue paper product according to claim 1, wherein the non-wood cellulose pulp fibres have an average fibre length of less than 1700 ?m.

26. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose pulp fibres have an average fibre length of less than 1200 ?m.

27. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose pulp fibres have an average fibre length of less than 900 ?m.

28. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose fibres have a breaking length of more than 3000 m.

29. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose fibres have a breaking length/average fibre length ratio of more than 3.7.

30. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose fibres have a breaking length/average fibre length ratio of more than 4.0.

31. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose fibres have a breaking length/average fibre length ratio of more than 4.5.

32. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose pulp fibres are derived from a member of the Pocacea family, such as from wheat straw, rice straw, barley straw, oat straw, rye grass, costal Bermuda grass, Arundo donax, miscanthus, bamboo, sugar cane bagasse and/or sorghum.

33. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose pulp fibres are derived from a member of the Cannabaceae family, such as from hemp and/or hop.

34. The single-ply tissue paper material according to claim 1, wherein the non-wood cellulose pulp fibres are agricultural waste or byproduct, such as derived from agricultural waste or byproduct of the Pocacea family and/or Cannabaceae family such as exemplified in the above, including agricultural waste or byproduct from wheat straw, rice straw, barley straw, oat straw, rye grass, sugar cane bagasse, hemp or hop and/or wherein the non-wood cellulose pulp fibres are derived from agricultural waste or byproduct such as banana harvest residue (belongs to the family Musaceae), pineapple residue (belongs to the family Bromeliaceae), nut shell waste, bagasse from agave, hop residue and/or corn stover.

35. The single-ply tissue paper material, a single ply tissue paper according to claim 1, wherein the non-wood cellulose pulp fibres are derived from kenaf (belongs to the family Malvaceae), switchgrass, succulents, alfalfa (belongs to the family Fabaceae.), flax straw (belongs to the family Linaceae), palm fruits (Elaeis or Arecaceae), and/or avocado (Lauraceae).

36. The single-ply tissue paper material according to claim 1, wherein said non-wood tissue ply or plies comprises said non-wood cellulose pulp fibres in an amount of at least 15%.

37. The single-ply tissue paper material according to claim 1, wherein said non-wood tissue ply or plies comprises said non-wood cellulose pulp fibres in an amount of at least 20% by dry weight.

38. The single-ply tissue paper material according to claim 1, wherein said non-wood tissue ply or plies comprises said non-wood cellulose pulp fibres in an amount of less than 70% by dry weight.

39. The single-ply tissue paper material according to claim 1, wherein said non-wood tissue ply or plies comprises said non-wood cellulose pulp fibres in an amount of less than 60% by dry weight.

40. The single-ply tissue paper material according to claim 1, wherein said non-wood tissue ply further comprises wood pulp fibres, such as hardwood cellulose pulp fibres and/or softwood cellulose pulp fibres.

41. The single-ply tissue paper material according to claim 40, wherein said non-wood tissue ply comprises wood pulp fibres in an amount such that the wood pulp fibre amount plus the non-wood fibre amount constitutes 100% dry weight of the non-wood tissue ply.

42. The single-ply tissue paper material according to claim 40, wherein the hardwood/softwood dry weight proportion of the wood pulp fibres in said non-wood tissue ply is less than 95/5.

43. The single-ply tissue paper material according to claim 40, wherein the hardwood/softwood dry weight proportion of the wood pulp fibres in said non-wood tissue ply is less than 90/10.

44. The single-ply tissue paper material according to claim 40, wherein the hardwood/softwood dry weight proportion of the wood pulp fibres in said non-wood tissue ply is less than 80/20.

45. The single-ply tissue paper material according to claim 1, wherein said non-wood cellulose pulp fibres are present throughout the non-wood tissue ply or plies.

46. The single-ply tissue paper material according to claim 1, wherein said non-wood tissue ply or plies comprises two or more layers, and at least one layer comprises non-wood fibres.

47. The single-ply tissue paper material according to claim 1, said non-wood tissue ply or plies being produced by conventional wet press technology (CWP).

48. The single-ply tissue paper material according to claim 1, said non-wood tissue ply or plies being produced by structured tissue technology, for example TAD (Through Air Drying), ATMOS, NTT(textured), UCTAD, QRT, eTAD or PrimeLineTEX.

49. The single-ply tissue paper material according to claim 1, wherein a portion of or all non-wood cellulose pulp fibres are never-dried non-wood cellulose pulp fibre.

50. The single-ply tissue paper material according to claim 1, comprising softwood cellulose pulp fibres and wherein a portion of or all softwood cellulose fibres are never-dried softwood cellulose pulp fibre.

51. The single-ply tissue paper material according to claim 1, comprising hardwood cellulose pulp fibres and wherein a portion of or all hardwood cellulose fibres are never-dried hardwood cellulose pulp fibre.

52. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0152] With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

[0153] In the drawings:

[0154] FIG. 1 is a diagram illustrating softness and GMT tensile strength for a number of base sheet samples including various amounts of non-wood fibre;

[0155] FIG. 2 is a diagram illustrating softness versus GMT tensile strengths for the base sheet samples of FIG. 1 including 0% non-wood fibre and 30% non-wood fibre;

[0156] FIG. 3 is a diagram illustrating softness and GMT tensile strength for a number of multiply tissue samples including various amounts of non-wood fibre;

[0157] FIG. 4 is a diagram illustrating the absorption for the tissue samples of FIG. 3; and

[0158] FIG. 5 is a diagram illustrating the thickness for the tissue samples of FIG. 3.

DETAILED DESCRIPTION

[0159] The description in the below relates to examples of tissue paper materials and tissue paper products as obtained using the non-wood cellulose pulp fibres as proposed herein.

Single-ply Tissue Paper Materials (Base Sheets)

[0160] Five different tissue paper materials were prepared.

[0161] The five different tissue paper materials are base sheets and suitable for forming bathroom tissue.

[0162] The samples were prepared using CWP technology to provide a dry creped tissue.

[0163] Two different grades of tissue were targeted:

Grade 1 (G1): soft bathroom tissue
Grade 2 (G2): standard bathroom tissue

[0164] The original fibre recipe for the two grades, without any non-wood fibre content is:

TABLE-US-00002 Trial ref Reference furnish Grade 50% softwood (never-dried pulp)- G1 50% hardwood (Eucalyptusdried pulp) Grade 70% softwood (never-dried pulp)- G2 30% hardwood (never-driepulp)

[0165] The trial aimed at introducing different levels of non-wood fibrous pulp instead of standard wood pulp to assess base paper properties and consequently finished product quality.

[0166] The tissue machine is a Crescent former with suction press roll configuration, with a 2 layers Headbox: 50% Top Layer, 50% Bottom Layer.

[0167] The G1 grade was run in a stratified mode (different recipes on the 2 layers of the base paper), the G2 grade was run in homogenous mode (same recipe on both layers of the base paper), with target specifications as in the below:

G1:

[0168] Headbox: 2 layers
Blade: 20? ceramic
Basis weight: 16.5 g/m2
Thickness (10p): 0.97 mm/10 plies
MD dry tensile/ply: 140 N/m
CD dry tensile/ply: 50 N/m
MD stretch: 18%

G2:

[0169] Headbox: 1 layer
Blade: 10? ceramic
Basis weight: 16 g/m2
Thickness (10p): 1.15 mm/10 plies
MD dry tensile/ply: 150 N/m
CD dry tensile/ply: 60 N/m
MD stretch: 16%

[0170] The amount of non-wood fibres introduced ranged from 0 to 50% of the total blend. The compositions of the various base sheets are indicated in the table in the below:

TABLE-US-00003 Grade Grade Grade 1 Grade 2 Trial Trial G 1A G1B G 2A G2B G2D G2E Overal hardwood (dried pulp) 50% 50% furnish softwood (never-dried pulp) 50% 30% 70% 50% 40% 30% hardwood (never-dried 30% 30% 30% 20% pulp) non-wood fibre (never-dried 0% 20% 0% 20% 30% 50% pulp)

[0171] The non-wood cellulose fibre pulp was derived from wheat straw, being treated according to the Phoenix TM process by Sustainable Fiber Solutions Inc. The non-wood fibre pulp was never-dried pulp. The non-wood fibre pulp had a lignin content of 12.8% and a hemicellulose content of 18.0%.

[0172] The conventional short fibre content was made out of Hardwood dried pulp being a Eucalyptus dried pulp, and Hardwood never-dried pulp being a hardwood never-dried sulfite pulp.

[0173] The conventional long fibre content was made out of Softwood. In this example, the Softwood fibre pulp was also never-dried sulfite pulp. The breaking length, average fibre length, and ratio breaking length/average fibre length of the hardwood never-dried pulp, softwood never-dried pulp and hardwood dried pulp (eucalyptus) were as indicated in the table below:

TABLE-US-00004 Softwood Hardwood Non- Hardwood (never- (never- wood (dried) dried) dried) Breaking length (m) 3775 1724 1755 882 Average fibre length 748 714 2165 929 (?m) Ratio breaking 5.05 2.41 0.81 0.95 length/fibre length (/micro)

[0174] The non-wood cellulose pulp fibres substituted mostly conventional long fibre both for its intrinsic strength properties and the tensile developed after refining. Despite this, additional strength generated needed a decrease on the long fibre refining line.

TABLE-US-00005 Grade Grade Grade 1 Grade 2 Trial Trial G 1A G1B G 2A G2B G2D G2E Long softwood 100% 100% 100% 100% 80% 60% fibre (never- line dried pulp) non-wood 20% 40% fibre Refining 60 50 70 32 32 37 kwh/T Short hardwood 100% 70% fibre (dried line pulp) hardwood 100% 60% 60% 40% (never- dried pulp) non-wood 30% 40% 40% 60% fibre Refining none none 15 18 48 Headbox Configuration Stratified Stratified Homogenous Homogenous Homogenous Homogenous Yankee 100% 100% 30% SF + 50% SF + 50% SF + 50% SF + layer SF SF 70% LF 50% LF 50% LF 50% LF Hood 100% 40% 30% SF + 50% SF + 50% SF + 50% SF + layer LF SF + 70% LF 50% LF 50% LF 50% LF 60% LF

[0175] The content of non-wood fibres, conventional long fibres, and conventional short fibres in each of the tissue paper materials is indicated in the table in the below:

TABLE-US-00006 Long fibre Short fibre Non wood Long fibre Short fibre line line Trial fibre content content refining refining Grade reference content % % kwh/T kwh/T Grade 1 G1-A 0% 50% 50% 60 0 (soft grade) G1-B 20% 30% 50% 50 0 Grade 2 G2-A 0% 70% 30% 70 0 (standard G2-B 20% 50% 30% 32 15 grade) G2-D 30% 40% 30% 32 18 G2-E 50% 30% 20% 37 48

[0176] Dry tensile strength in CD and MD directions and panel softness, were measured for the various samples, with the results as indicated in the table in the below and in FIGS. 1 and 2.

TABLE-US-00007 Basis MD dry CD dry GMT dry weight tensile tensile tensile MD stretch g/m.sup.2 N/m - 1 ply N/m - 1 ply N/m - 1 ply % Panel G1 - A 16.8 145 51 86 20.1 2.7 G1 - B 17.2 151 56 92 18.6 2.7 G2 - A 16.1 130 54 83 19.2 2.5 G2 - B 16.2 156 64 100 18.2 2.6 G2 - E 16.5 192 81 125 18.8 2.1

[0177] FIG. 1 is a combined bar chart and linear chart, where the bars represent the softness values and the line indicates the GMT tensile strength of the tissue paper materials G1-A, G1-B, G2-A, G2-B, and G2-E of Table 1.

[0178] The samples of the different Grades denoted A, are all samples with no non-wood fibre content, whereas the samples of the different Grades denoted with other letters include increasing amounts of non-wood fibre content (in alphabetical order).

[0179] No general trend for the relationship between the GMT strength and the softness in view of the non-wood cellulose fibre content may be seen which is valid for all of the different Grades. For the grade G1 being the softer grade, the softness values with or without non-wood fibres are similar. For the grade G2 being the standard grade, the softness values deviate more, but the GMT strength is increasing with increasing non-wood content.

[0180] Surprisingly the GMT strength is seen to increase with increasing content of non-wood fibre in the two different grades. Turning to FIG. 2, the basesheet softness and strength are again visualized, this time for samples including 0% non-wood versus samples including 30% non-wood. The samples with 30% non-wood display advantageous softness and GMT tensile strength.

[0181] Further, another surprising result is that all of the Grades display a GMT strength and a softness which is within limits rendering them useful for tissue paper products.

Multi-ply Products

[0182] Three different types of multi-ply products, MP1, MP2 and MP3 were prepared. For each type of multi-ply product, samples were made with different overall non-wood fibre content, using the base sheets of different grades and non-wood fibre content as described in the above.

[0183] The plies of the multi-ply products were assembled by means of Goffra-Incolla technology. All converting parameters were the same for the different non-wood content of each of the products MP1, MP2, MP3.

MP1:

[0184]

TABLE-US-00008 4-ply product Basesheet Basesheet Basesheet Embossing Basesheet Middle Middle ply Bottom top ply Top ply ply 2 ply MP1 0% Feather Grade 1 A Grade 2 A Grade 2 A Grade 1 A (RT 20D) MP1 32% Feather Grade 1 B Grade 2 E Grade 2 E Grade 1 B (RT 20D)

MP2:

[0185]

TABLE-US-00009 4-ply product Basesheet Basesheet Basesheet Embossing Basesheet Middle Middle ply Bottom top ply Top ply ply 2 ply MP2 0% Ornament Grade 1 A Grade 2 A Grade 2 A Grade 1 A (RT71D) MP2 20% Ornament Grade 1 B Grade 2 B Grade 2 B Grade 1 B (RT71D) MP2 30% Ornament Grade 1 B Grade 2 E Grade 2 E Grade 1 B (RT71D)

MP3:

[0186]

TABLE-US-00010 3-ply product Basesheet Basesheet Basesheet Embossing Basesheet Middle Middle ply Bottom top ply Top ply ply 2 ply MP3 0% Seven Grade 1 A Grade 2 A Grade 1 A (RT305) MP3 20% Seven Grade 1 B Grade 2 B Grade 1 B (RT305) MP3 30% Seven Grade 1 B Grade 2 E Grade 1 B (RT305)

[0187] The resulting multi-ply tissues were tested for various parameters, and the results are displayed in the below table.

TABLE-US-00011 Number Non-wood of dry weight Basis Thickness (average) weight (1 sheet) GMT Softness Absorption plies % Firmness (g/m.sup.2) mm N/m Panel g/g MP1 0% 4 0 61 63.8 0.58 267 1.7 9.0 MP1 32% 4 32 60 64.8 0.57 335 1.7 8.6 MP2 0% 4 0 59 63.0 0.53 255 1.7 9.3 MP2 20% 4 20 55 65.8 0.55 309 1.6 8.8 MP2 30% 4 30 54 65.9 0.55 329 1.5 9.0 MP3 0% 3 0 54 46.3 0.43 167 1.6 9.6 MP3 20% 3 20 47 48.2 0.44 200 1.6 9.0 MP3 30% 3 30 48 48.2 0.44 206 1.6 9.3 indicates data missing or illegible when filed

[0188] The results will be further discussed in the below with reference to FIGS. 3 to 6.

[0189] FIG. 3 is a combined bar chart and linear chart, where the bars represent the softness values of the samples and the line indicates the GMT tensile strength.

[0190] In FIG. 3, as well as in the following FIGS. 4 to 6, for each type of multiply tissue paper material MP1, MP2, MP3, the samples are presented from left to right and with the sample having 0 percentage non-wood content to the left, and in increasing order of non-wood content towards the right in the figures.

[0191] As demonstrated by FIG. 3, the softness values for each type of multiply tissue paper material MP1, MP2, and MP3 is relatively constant or decreases only insignificantly with increasing amount of non-wood content. (A significant difference in the softness values (panel softness) would be about 0.2 points.) Thus, the results indicate that the softness is not significantly affected in the samples including various amounts of non-wood as compared to the samples including no non-wood.

[0192] Further, for each of the types MP1, MP2, and MP3, the GMT tensile strength increases with increasing amount of non-wood content. The increase in GMT tensile strength is significant, which was surprising. Thus, the results indicate that the GMT tensile strength is significantly increased in the samples including various amounts of non-wood as compared to the samples including no non-wood.

[0193] Thus, the results indicate that the balance between the softness and GMT strength in the samples including various amounts of non-wood, is better than for the samples with no non-wood content, i.e. increased GMT strength is achieved at about the same softness.

[0194] A satisfactory result for a tissue paper product including non-wood would be a balance being about the same as for a tissue paper product with no non-wood content. Based on the tests performed, it may therefore be assumed that the non-wood cellulose pulp fibres used herein are useful for replacing wood fibres in numerous different multi-ply and single ply tissue paper products while achieving at least satisfactory results in terms of softness and strength.

[0195] Turning to absorption, FIG. 4 is a bar chart illustrating the absorption g/g of the different samples of the three types of tissue paper material MP1, MP2, and MP3. As seen in the results, for each of the types MP1, MP2, and MP3, the highest value for absorption is obtained for the sample with no non-wood content. However, no general trend regarding the impact of increasing non-wood amount on the absorption values may be seen. Further, the variations in the measured absorption values are mainly insignificant, as a significant difference for absorption is about 0,5 g/g.

[0196] Thus, the results indicate that the absorption is not significantly affected in the samples including various amounts of non-wood, and instead the absorption is as good in the samples with various amounts of non-wood content as in the sample including no non-wood.

[0197] Turning to thickness, FIG. 5 is a bar chart illustrating the thickness (mm) of the different samples of the three types of tissue paper material MP1, MP2, and MP3. The results indicate that the thickness is not significantly affected in the samples including various amounts of non-wood as compared to the samples including no non-wood.

[0198] Thus, in summary, the results indicate that introduction of various amounts of the non-wood cellulose fibres into different tissue paper materials results in acceptable or insignificant changes in parameters relevant for the function of the tissue paper material, such as the GMT strength, the softness, the absorption and/or the thickness, as compared to the same tissue paper material without non-wood fibre content.

[0199] The advantageous results are believed to be at least partially due to the use of the non-wood fibres, and in particular the various features which may be contributing to the advantageous properties of tissue paper materials and products including the non-wood fibres as set out in the above.

[0200] For example, as in the samples in the above, the non-wood cellulose pulp fibre may have a breaking length/average fibre length ratio greater than 4. Also, the non-wood pulp fibres may be never-dried. Further, the non-wood cellulose pulp fibres may be derived from agricultural waste or byproducts such as one out of wheat straw, oat straw, barley straw, and/or rye grass, for example wheat.

[0201] However, other combinations of features as described in the above for the non-wood cellulose fibres may be made by a person skilled in the art to provide the tissue materials and tissue products as proposed herein.

[0202] Hence, the results, although relating to specific examples of tissue paper materials and tissue paper products are believed to indicate that the non-wood fibres as such may be used to provide advantageous results in for a wider range of tissue paper materials and tissue paper products.

Definitions

[0203] Tissue paper material: The term tissue paper material as used herein refers to the one-ply base tissue as obtained from a tissue machine.

[0204] Layer: The tissue paper material may include one or more layers, i.e. it may be a single-layered or a multi-layered web. The term layer refers to a stratum within the web having a defined fibre composition. The one or more layers is/are formed by depositing one or more streams of pulp furnishes onto a wire with a pressurized single-or multi-layered headbox.

[0205] Ply: The term ply as used herein refers to the one or more plies of tissue paper material in the final tissue paper product as are obtained after processes, i.e. converting, one or more base tissue webs. Each individual ply consists of a tissue paper material including one or more layers, e.g. one, two, or three layers.

[0206] Hardwood: As hardwood we understand herein fibrous pulp derived from the woody substance of deciduous trees (angiosperms). For example, hardwood includes eucalyptus. Typically, hardwood fibres are relatively short fibres. For example, the hardwood fibres may have an average fibre length less than 1700 ?m. The hardwood fibres may for example have a diameter of 15 to 40 ?m and a wall thickness of 3 to 5 ?m.

[0207] Softwood: as softwood we understand fibrous pulp derived from the woody substance of coniferous trees (Gymnosperms). Typically, softwood fibres are relatively long fibres. For example, the softwood fibres may have an average fibre length above 1700 ?m, such as above 1950 micron, for example the soft wood fibres may have an average fibre length in a range from 1700 to 2500. ?m. The softwood fibres may for example have a diameter of from 30 to 80 ?m, and a wall thickness of from 2 to 8 ?m.

[0208] Conventional short fibres: As conventional short fibres we understand herein hardwood fibres as described in the above. Generally, the conventional short fibres may have an average fibre length less than 1700 ?m.

[0209] Conventional long fibres: As conventional long fibres we understand herein softwood fibres as described in the above. Generally, the conventional long fibres may have an average fibre length greater than 1700 ?m.

CWP & Structured Tissue Technology:

[0210] As described in the above, paper tissue webs can be produced in several ways. Conventional paper machines have been used for many years for that purpose, to produce such conventional webs at a relatively low cost.

[0211] An example of a conventional paper tissue web process is the dry crepe process which involves creping on a drying cylinder, the so-called yankee cylinder, by means of a crepe doctor. Wet creping can be used as well, if there are lower demands on the tissue quality. The creped, finally dry raw tissue paper, the so-called base tissue, is then available for further processing into the paper product for a tissue paper product.

[0212] Recently, more advanced methods have been developed, such as e.g. Through Air Drying (TAD), Advanced Tissue Molding System (ATMOS) and similar methods for producing structured tissue webs. A common feature for these latter methods is that they result in a more structured web with a lower density than a web produced on a conventional paper machine.

[0213] As used herein the term CWP technology (Conventional Wet Pressed technology) refers to conventional paper web processes, in which the tissue is formed on a forming fabric and dewatered by pressing with one or more pressure roll nips. The process may involve transfer of the sheet to a Yankee dryer and removing the sheet from the Yankee surface by a doctor blade in a creping process. CWP technology as used herein includes for example dry crepe technology, wet crepe technology, and flat NTT (New Tissue Technology).

[0214] As used herein, the term structured tissue technology relates to the newer technologies for producing a structured tissue web. Such methods will not employ the high pressure used to dewater the web in the CWP process. Therefore, structured tissue technology is sometimes referred to as non-compressing de-watering technology. The structured tissue technology may for example be TAD (Thru-Air-Dried), UCTAD (Uncreped-Through-Air-Dried) or ATMOS (Advanced-Tissue Molding-System), textured NTT, QRT, PrimeLineTEX technology and eTAD technology.

[0215] The structured tissue technology methods are known from prior art, for example TAD is known from US5853547; and ATMOS from US 7744726, US7550061 and US7527709; and UCTAD from EP 1 156925 and WO 02/40774.

[0216] TAD technology has been developed since the 1960's and is well known to a person skilled in the art. It generally involves developing functional properties of the tissue by moulding the fibre mat on a structured fabric. This results in the fibre mat forming a structured tissue which may acquire high bulk and absorption due to air passing through the web while drying the web when still on the structured fabric.

[0217] ATMOS technology is a production method developed by Voith and which is also well known to a person skilled in the art.

[0218] Another example is textured NTT (New Tissue Technology). Textured NTT was designed to overcome some of the limitations of ATMOS by pressing at even higher pressures before transferring to the Yankee. A shoe press is used in the first pressing section between the former felt and a belt with cells designed to provide absorptive capacity and increase strength. The NTT technology may reduce the Yankee Hood drying load as compared to ATMOS.

[0219] Yet other examples are Prime Line Tex technology as rendered available by Andritz for production of textured tissue, and eTAD technology as rendered available by Valmet.

Methods

[0220] Lignin content:
The measurement of residual lignin content in the pulp fibres has been carried out according to the draft standard ISO/DIS 21436: Pulps-Determination of lignin contentMethod of acid hydrolysis 1), which includes: [0221] i) the gravimetric measurement of the residue after acid hydrolysis (AIL : Acid Insoluble Lignin or Klason Lignin), also described in the Tappi T222 om-02 method 2; and [0222] ii) the measurement of soluble lignin (ASL : Acid Soluble Lignin), also described in the technical note Tappi UM2503.

[0223] 3.1) Sample preparation: The samples were disintegrated with a grinder/mixer. Their dry matter contents were determined before analysis, by drying in an oven of an aliquot of 2-3 g at 105? C., according to the ISO 638 standard 4.

[0224] 3.2) Measurement of acid insoluble lignin (AIL or Klason lignin) after acid hydrolysis An aliquot of ?1 g was hydrolysed with a solution of sulfuric acid, firstly at ambient temperature (2 h) and then under reflux during 4 h (Procedure B of the future standard). After cooling, the suspension was filtered and washed and the solid residue was collected, dried and weighted. The acid insoluble lignin content in the sample was determined by difference between the dry hydrolysis residue weight and the ash weight, reported to the dry mass content of the initial sample. Note 1: Detection limit (DL) ?0.1%; Quantification limit (QL) ?0.5%.

[0225] 3.3) Measurement of acid soluble lignin. The absorbance at 205 nm of the hydrolysate (i.e. the filtrate collected during the filtration of the suspension, cf 3.2), were measured. The acid soluble lignin content (ASL) was determined according to the predefined extinction coefficient of the lignin (i.e. 110 L/g.cm). Note 2: : Detection limit (DL) ?0.1%;

Quantification Limit (QL) ?0.5% Remark: This quantification method is sensitive to the contaminants being present into the sample. Each compound other than hemicelluloses and cellulose and the acid insoluble minerals are susceptible to interfere with the measurement of the hydrolysis residue and with the acid soluble lignin.

Hemicellulose

[0226] The determination of the contents of the main polysaccharides in the pulp (arabinane, galactane, glucane, xylene, and mannane) has been made by using high performance anion exchange chromatography with a pulsed amerometric detector, HPAE/PAD-Dionex? analysis of free monosaccharides (arabinose, galactose, glucose, xylose and mannose) after sulphuric acid hydrolysis of the sample pulp. The cellulose and the hemicellulose content in the pulp sample is determined according to standard method ISO/DIS21437Pulps: Determination of carbohydrate (under publication) after calibration. The samples studied are chemical pulp which has not required extraction of aceton beforehand. In contrast, the samples have been dried. However, considering the pulp state (wet lap sheets), samples were grinded before analysis. Dry content of the grinded samples was measured according to NF EN ISO 638:2008.

[0227] Basically the method is quantifying the amounts of sugars (monosaccharides) after hydrolysis of cellulose and hemi using the ISO/DIS 21437Pulps: Determination of carbohydrate. Then, calculation is made backwards to estimate level of hemicelluloses (knowing proportion of sugars in hemi and cellulose)

Basis Weight

[0228] Basis weight is determined in accordance with ISO 12625-6: 2016.

[0229] The basis weight is determined in g/m.sup.2.

Thickness per Sheet:

[0230] Thickness is determined in accordance with ISO 12625-3.

GMT Strength:

[0231] GMT strength (Geometric Mean Tensile strength) refers to the square root of the product of the machine direction dry tensile strength and the cross-direction dry tensile strength of a tissue web/product.

[0232] The GMT strength is determined in accordance with ISO 12625-4.

[0233] A load cell of 100N was used.

Absorption:

[0234] Absorption is herein the water absorption capacity of the tissue paper. Water absorption capacity is the amount of water the sample is able to absorb, reported in g/g (i.e. g water/g material in sample).

[0235] Absorption was measured according to ISO12625-8:2011.

[0236] The water is deionized water, conductivity ? 0.25 mS/m at 25? C., in accordance with ISO14487.

Softness panel:

[0237] Panel softness is determined by evaluation made by panel members. The panelists rank products in terms of softness. The Softness Panel values are therefore comparative values enabling a comparison between the samples tested, rather than an absolute parameter.

[0238] The softer the product/tissue base sheet is rated the higher the value will be.

[0239] Softness values of tissue paper products (finished goods) and tissue base sheets are not directly comparable as there are different scales/reference products.

[0240] Each sample is composed of one product, i.e. a multi-ply tissue paper product.

[0241] The dimensions of the samples are therefore the dimensions of the finished products.

[0242] Samples are placed in MD before the panelists.

[0243] Samples are conditioned for minimum 2 hours in a controlled area at 23?C and 50% relative humidity.

[0244] The different samples are comfort rated by ten panelists, and an average comfort rating for each product is determined over the panelists.

[0245] Hence, softness panel values are comparative values within a test and indicate the perceived softness of a product.

[0246] For the purpose of this application, softness panel values given in one and the same table are comparable and indicate the perceived relative softness of the products tested. The higher the value of the rating, the more comfortable is the product.

Average Fibre Length Measurement:

[0247] Fibre length measurement was made using the standard for fibre analyser: ISO 16065-2:2014: PulpsDetermination of fibre length by automated optical analysisPart 1: Unpolarized light method.

[0248] Length-weighted mean length was used and the average of the lengthweighted fibre-length distribution.

Breaking Length Measurement

[0249] The breaking length is the calculated upper limit of length of a uniform paper strip that would support its own weight if it were suspended at one end. Breaking length (m)=102?T/R, where T=Tensile strength, N/m, and R=basis weight, g/m2.

[0250] The breaking length is a pulp characteristic obtained by tensile strength and basis weight measurements as measured on lab handsheets produced in accordance with EN ISO 5269-2. (Tensile strength: ISO 12625-4; basis weight: ISO 12625-6: 2016)

Ratio of Breaking Length Measurement/Average Fibre Length Measurement

[0251] The ratio of breaking length/average fibre length is herein using the values of the fibre length measurement and the breaking length measurements as achieved according to the methods in the above, the average fibre length measurement being reported in ?m, and the breaking length being reported in m.

[0252] It may be noted that the breaking length, as well as the average fibre length, are pulp characteristics. Accordingly, the measurements of these properties are to be performed on the pulp as received from the pulping process, before reaching the papermaking process, such as before entering the stock preparation in a paper machine. Thus, the measurements are done prior to any mechanical and/or chemical and/or enzymatic treatment for strength adjustment which may occur during the paper making process.