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TISSUE PAPER MATERIAL AND TISSUE PAPER PRODUCT INCLUDING NON-WOOD FIBRES

20240318385 ยท 2024-09-26

    Inventors

    Cpc classification

    International classification

    Abstract

    A single-ply tissue paper material having a basis weight less than 40 gsm and an absorbency of at least 3 g/g, 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 non-wood tissue ply. The disclosure further relates to a single-ply tissue paper product, and a multi-ply tissue paper product.

    Claims

    1. A single-ply tissue paper material having a basis weight less than 40 gsm and an absorbency of at least 3 g/g, comprising a non-wood tissue ply, said 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.

    2. A single-ply tissue paper material according to claim 1, wherein the tissue paper material has an absorbency of at least 4 g/g.

    3. The single-ply tissue paper material according to claim 1, wherein the tissue paper material has an absorbency of at least 5 g/g.

    4. The single-ply tissue paper material according to claim 1 being produced by CWP (Conventional Wet Pressed) technology.

    5. The single-ply tissue paper material according to claim 1, being produced by structured tissue technology and having an absorbency of at least 6 g/g.

    6. The single-ply tissue paper material according to claim 1, being produced by structured tissue technology and having an absorbency of at least 7 g/g.

    7. The single-ply tissue paper material according to claim 1, being produced by structured tissue technology and having an absorbency of at least 8 g/g.

    8. The single-ply tissue paper material according to claim 1, wherein the tissue paper material has a GMT tensile strength of at least 60 N/m.

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

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

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

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

    13. The single-ply tissue paper material according to claim 1, having a basis weight of more than 10 gsm.

    14. The single-ply tissue paper material according to claim 1, having a basis weight of more than 15 gsm.

    15. (canceled)

    16. (canceled)

    17. (canceled)

    18. (canceled)

    19. The multi-ply tissue paper product according to the claim 1, wherein at least one ply of the multi-ply tissue paper product is produced by CWP (Conventional Wet Pressed) technology.

    20. (canceled)

    21. (canceled)

    22. (canceled)

    23. (canceled)

    24. (canceled)

    25. (canceled)

    26. (canceled)

    27. (canceled)

    28. (canceled)

    29. (canceled)

    30. (canceled)

    31. (canceled)

    32. (canceled)

    33. (canceled)

    34. (canceled)

    35. (canceled)

    36. (canceled)

    37. (canceled)

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

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

    40. 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 1700 ?m.

    41. 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.

    42. 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.

    43. 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.

    44. 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.

    45. 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.

    46. 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.

    47. 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.

    48. 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.

    49. 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.

    50. The single-ply tissue paper material 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).

    51. 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%.

    52. 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%.

    53. 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.

    54. 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.

    55. 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.

    56. The single-ply tissue paper material according to claim 55, 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.

    57. The single-ply tissue paper material according to claim 55, wherein the hardwood/softwood dry weight proportion of the wood pulp fibres in said non-wood tissue ply is less than 95/5.

    58. The single-ply tissue paper material according to claim 55, wherein the hardwood/softwood dry weight proportion of the wood pulp fibres in said non-wood tissue ply is less than 90/10.

    59. The single-ply tissue paper material according to claim 55, wherein the hardwood/softwood dry weight proportion of the wood pulp fibres in said non-wood tissue ply is less than 80/20.

    60. 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.

    61. 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 cellulose pulp fibres.

    62. 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).

    63. 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, textured NTT, UCTAD, eTAD, QRT or PrimeLineTEX.

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

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

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

    67. (canceled)

    Description

    BRIEF DESCRIPTION OF THE DRAWINGS

    [0189] With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

    [0190] In the drawings:

    [0191] FIG. 1 is a diagram of absorbency values obtained for tissue paper materials obtained in Example 1;

    [0192] FIG. 2a is a diagram of absorbency values obtained for tissue paper materials obtained in Example 2;

    [0193] FIG. 2b is a diagram of absorbency values obtained for tissue paper products obtained in Example 2;

    [0194] FIG. 3 is a diagram of absorbency values obtained for tissue paper products obtained in Example 3;

    [0195] FIG. 4 is a diagram of absorbency values obtained for tissue paper products obtained in Example 4; and

    [0196] FIG. 5 is a diagram of absorbency values obtained for the tissue paper products obtained in Example 5, including variants of the tissue paper products obtained in Example 2.

    DETAILED DESCRIPTION

    Example 1 (TAD Tissue Paper Material)

    [0197] One-ply tissue paper materials intended for use as kitchen towels were produced using TAD technology with different dry content of non-wood fibre.

    [0198] Two versions of the tissue paper materials were made, one including 0% dry weight non-wood fibres, and one including 30% by dry weight non-wood fibres.

    [0199] The non-wood fibre pulp was derived from wheat straw, being treated according to the Phoenix? process by Sustainable Fiber Solutions Inc. The non-wood fibre pulp was never-dried pulp. The non-wood fibre pulp of this type generally has a lignin content of less than 15% and a hemicellulose content of more than 15%.

    [0200] The breaking length, average fibre length, and ratio breaking length/average fibre length of the non-wood cellulose fibre pulp are indicated in the table below:

    TABLE-US-00002 Non-wood fibre Breaking length [m] 5338 Average fibre length[?m] 854 BL/av fibre length 6.25

    [0201] The conventional short fibre content was made out of dried hardwood cellulose fibre pulp. The dried hardwood cellulose fibre pulp was dried Eucalyptus fibre pulp, BEK (Bleached Eucalyptus Kraft).

    [0202] The conventional long fibre content was made out of dried softwood cellulose fibre pulp. In this example, the dried softwood cellulose fibre pulp was NBSK (Northern Bleached Softwood Kraft).

    [0203] The breaking length/average fibre length ratio of BEK in general has been found to be about 2.4, and the breaking length/average fibre length ratio of NBSK has been found to be about 1.2, as indicated in the table in the Summary section in the above.

    [0204] The machine was a stratified machine with 3 layers headbox, fed with 2 fibre lines: [0205] The long fibre line is feeding the Hood and Yankee layers of the headbox [0206] the short fibre line is feeding the middle layer of the headbox

    [0207] The overall furnish of the reference and the trial were the following [0208] Reference: 42% BEK-58% NBSK [0209] Trial: 12% BEK-58% NBSK-30% straw

    [0210] The different fibres were split and treated as follow:

    TABLE-US-00003 Trial Trial reference trial Overall NBSK 58% 58% furnish BEK 42% 12% Non-wood 0 30% Long NBSK 83% 83% fibre Non-wood 17% 17% line Refining 160 kwh/T 160 kwh/T Short BEK 100% 0% fibre Non-Wood 0% 100% line Refining 30 kwh/T none Headbox Configuration stratified stratified Yankee layer 41.5% NBSK + 41.5% NBSK + 8.5% BEK 8.5% BEK Middle layer 100% BEK 100% Non- wood Hood layer 41.5% NBSK + 41.5% NBSK + 8.5% BEK 8.5% BEK

    [0211] Chemistry was added to provide dry and wet tensile strength, and was kept constant for the different qualities.

    [0212] The average base sheet properties are as follows

    TABLE-US-00004 Dry Dry Wet Wet Basis Thickness tensile tensile Stretch tensile tensile weight (1 sheet) MD CD MD GMT MD CD ABSORPTION (g/m.sup.2) mm (N/m) (N/m) (%) (N/m) (N/m) (N/m) (g/g) Reference 22.1 0.43 257 189 15.0 220 87.1 68.4 13.7 Trial 30% 22.4 0.45 276 205 13.9 237 87.5 63.4 14.5 Non-wood

    [0213] Despite no refining on the short fibre line, the tissue paper material containing non-wood fibres tends to be stronger than the reference paper material without non-wood.

    [0214] As seen from the values in the table in the above, and as illustrated by the diagrams in FIG. 1, the trial with non-wood is significantly more absorbent than the reference tissue paper material without non-wood.

    [0215] Thus, the tissue paper material including 30% non-wood fibres was even more absorbent than the tissue paper material including 0% non-wood fibre.

    Example 2 TAD Tissue Paper Material and 2-Ply TAD Tissue Paper Product

    [0216] Two-ply tissue paper products intended for use as kitchen towels were produced using TAD technology. The two-ply tissue paper products were produced from tissue paper materials (base sheets) produced using TAD technology and with different dry content of non-wood fibre.

    [0217] The non-wood fibre pulp was derived from wheat straw, being treated according to the Phoenix? process by Sustainable Fiber Solutions Inc. The non-wood fibre pulp was never-dried pulp. The non-wood fibre pulp of this type generally has a lignin content of less than 15% and a hemicellulose content of more than 15%.

    [0218] The breaking length, average fibre length, and ratio breaking length/average fibre length of the non-wood cellulose fibre pulp are indicated in the table below:

    TABLE-US-00005 Non-wood fibre Breaking length [m] 5493 Average fibre length[?m] 861 BL/av fibre length 6.38

    [0219] The softwood cellulose fibre pulp and the hardwood cellulose pulp were similar to those used in Example 1 in the above.

    [0220] Tissue paper material 1 (TP1) was made using 0% dry content of non-wood fibres.

    [0221] Tissue paper material 2 (TP2) was made using 20% dry content of non-wood fibres.

    [0222] Tissue paper material 3 (TP3) was made using 30% dry content of non-wood fibres.

    [0223] The proportions between the conventional short fibre i.e. the Eucalyptus fibre pulp BEK (Bleached Eucalyptus Kraft), the conventional long fibre content, i.e. the Softwood fibre pulp NBSK (Northern bleached softwood kraft), and the non-wood fibres are indicated in the table in the below.

    TABLE-US-00006 Conditions TP1 (0%) TP2 (20%) TP3 (30%) Overall BEK 25% 5% furnish NBSK 75% 75% 70% Non-wood 20% 30% Refining Long 160 150 150 kwh/T fibres Refining Short 32 Off Off kwh/T fibres

    [0224] The machine was a stratified machine. Long fibre line was feeding Hood and Yankee layers of the headbox; the short fibre line feeding the middle layer.

    [0225] For TP1, Long fibre line was 100% NBSK, and Short fibre line was eucalyptus BEK.

    [0226] For TP2 and TP3, non-wood fibre substituted or all of the eucalyptus (BEK). The non-wood fibre was not refined.

    [0227] Chemistry was added to provide dry and wet tensile strength, and was kept constant for the 3 qualities TP1, TP2 and TP3.

    [0228] Chemical flows were equally split between both fibre lines.

    [0229] Basis weight, thickness, dry tensile strength and absorption were measured for the resulting tissue paper materials. The results are indicated in the table in the below.

    TABLE-US-00007 Dry Dry Non- Basis Thickness tensile tensile Absorp- wood weight 1 sheet MD CD tion content (g/m2) (mm) (N/m) (N/m) GMT (g/g) TP1 0% 21.2 0.4 334 245 286 14.0 TP2 20% 21.3 0.4 265 232 248 13.9 TP3 30% 21.4 0.4 279 234 255 14.7

    [0230] FIG. 2a is a diagram illustrating the absorption of the tissue paper material including 0% non-wood cellulose pulp fibres as compared to the absorption of the tissue paper material including 30% non-wood cellulose pulp fibre.

    [0231] As seen in FIG. 2a and indicated in the table, the tissue paper material including 30% non-wood fibre displayed better absorption than the tissue paper material including 0% non-wood fibre. The tissue paper material including 20% non-wood cellulose pulp fibre displayed similar absorption as the tissue paper material including 0% non-wood cellulose pulp fibre.

    [0232] The tensile strength of the tissue materials including non-wood cellulose pulp fibre is slightly less than the tensile strength of the tissue material with no non-wood cellulose pulp fibre. However, the deviation in tensile strength is not very significant and the tensile strength is still within acceptable limits.

    [0233] Two-ply products were formed using the reference tissue paper material TP1 including 0% non-wood fibre and the tissue paper material TP3 including 30% non-wood fibre as described in the above.

    [0234] 2-ply product 1 (2P-1): 2 plies of the TP1, meaning that the 2-ply product includes 0% non-wood fibres.

    [0235] 2-ply product 2 (2P-2): 2 plies of TP3, meaning that the 2-ply product includes 30% dry weight non-wood fibres.

    [0236] The 2-ply tissue paper products were produced by assembling the tissue paper materials (base sheets) using nested 2-ply technology.

    [0237] Basis weight, thickness, tensile strength, softness panel and absorption was measured for the three multi-ply products. The results are indicated in the table in the below.

    TABLE-US-00008 Dry Dry Basis Thickness tensile tensile Straw weight 1 sheet MD CD GMT Softness Absorption content (g/m2) (mm) (N/m) (N/m) (N/m) panel (g/g) 2P-1 0% 41.5 0.72 647 457 544 5.6 13.5 2P-2 30% 41.1 0.74 581 431 500 5.5 14.4

    [0238] FIG. 2b illustrates the absorption of the two-ply tissue paper products. As seen in FIG. 2b and in the table above, the two-ply tissue paper product including 30% by dry weight non-wood fibres (2P-2) displayed a higher absorption at a comparable basis weight and thickness than the two-ply tissue paper product including no non-wood fibres.

    [0239] The dry tensile strength results of the two-ply tissue paper product including 30% by dry weight of non-wood fibres (2P-2) were satisfactory to the intended use of the two-ply tissue paper product as a kitchen towel. Further, the softness of the two-ply tissue paper product including 30% by dry weight non-wood fibres (2P-2) displayed a similar softness to the two-ply tissue paper product including no non-wood fibres.

    [0240] In all, the results indicate that the two-ply tissue paper products including non-wood fibres will display at least a similar absorption as the multi-ply tissue paper product including no non-wood fibre. Also, dry tensile strength and softness of the two-ply tissue products are satisfactory. Accordingly, the benefits obtained by using non-wood fibres may be obtained while still achieving a satisfactory tissue paper product.

    Example 3 (CWP Tissue Paper Product)

    [0241] Three-ply tissue paper products intended for use as kitchen towels were produced using CWP technology. The three-ply tissue paper products were produced from tissue paper materials (base sheets) produced using CWP technology and with different dry content of non-wood fibre.

    [0242] The pilot machine used was a Crescent former with suction presser roll configuration, with a 2 layers Headbox: 50% Top Layer, 50% Bottom Layer.

    [0243] The machine was run in homogenous mode (same recipe on both layers of the base paper), but 2 fibre lines were used and treated differently.

    [0244] The amount of non-wood fibre introduced ranged from 0 to 50% of the total blend for producing the tissue paper materials (base sheets).

    [0245] The non-wood fibre pulp was derived from wheat straw, being treated according to the Phoenix? 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.

    [0246] The conventional short fibre content was made out of Hardwood. The Hardwood fibre pulp was never-dried pulp.

    [0247] The conventional long fibre content was made out of Softwood. In this example, the Softwood fibre pulp was also never-dried pulp. The breaking length and morphology of the hardwood and softwood fibre pulp were as indicated in the table below:

    TABLE-US-00009 Non-wood Softwood Hardwood (never- (never- (never- dried) dried) dried) Breaking length (m) 3775 1755 882 Average fibre length 748 2165 929 (microm) Fibre width (microm) 20 29 21 Fibre coarseness 0.13 0.20 0.13 (mg/m) Ration breaking 5.05 0.81 0.95 length/fibre length (/micro)

    [0248] The composition of the different tissue paper materials (base sheets) and the refining level used is indicted in the below

    TABLE-US-00010 Long Short Long Short Non- fibre fibre fibre line fibre line Trial wood content content refining refining reference content % % kwh/T kwh/T G3-A 0% 85% 15% 150 0 G3-B 20% 65% 15% 120 10 G3-C 50% 45% 5% 80 10

    [0249] The different fibres were split in the different layers of the stock preparation as follows:

    TABLE-US-00011 Trial Trial G3-A G3-B G3-C Overall softwood (never 85% 65% 45% furnish dried pulp) hardwood (never 15% 15% 5% dried pulp) Straw 0% 20% 50% Long softwood (never 100% 100% 100% fibre dried pulp) line Straw 0% 0% 0% Refining kwh/T 150 120 80 Short hardwood (never 100% 43% 9% fibre dried pulp) line Straw 57% 91% Refining No 10 10 Headbox Configuration Homogenous Homogenous Homogenous Yankee layer 85% LF + 65% LF + 45% LF + 15% SF 35% SF 55% SF Hood layer 85% LF + 65% LF + 45% LF + 15% SF 35% SF 55% SF

    [0250] Chemistry was added to provide dry and wet tensile strength, and was kept constant for the different qualities.

    Average Base Sheet Properties

    [0251]

    TABLE-US-00012 Strech MD CD Trial BW Caliper MD MD CD wet Wet Dry/Wet reference g/m2 mm/10-ply N/m % N/m N/m N/m % Non- Target 18 1.2 290 17 145 90 30 25 wood Min 17.5 0.9 280 15 130 65 25 21 content Max 18.5 1.4 350 19 170 100 35 G3-A 0% Average 17.9 0.97 299 18.3 136 77 27 26 std 0.3 0.11 14 1.4 8 2 3 2 G3-B 20% Average 18.5 0.95 327 17.9 141 85 28 26 std 0.5 0.08 38 3.0 15 10 4 4 G3-C 50% Average 18.7 1.00 293 16.7 139 67 23 23 std 0.6 0.03 17 1.7 10 11 1 3 Non- Long fibre Short fibre Long fibre Short fibre Trial wood content content line refining line refining Absorption reference content % % kwh/T kwh/T GMT g/g G3-A 0% 85% 15% 150 0 201 6.7 G3-B 20% 65% 15% 120 10 215 6.5 G3-C 50% 45% 5% 80 10 202 6.3

    [0252] Despite the lower long fibre content and the lower refining level, the tissue paper materials with non-wood cellulose pulp fibre had similar or higher tensile strength than the tissue paper material without non-wood cellulose pulp fibre.

    [0253] As for absorption, the tissue paper materials with non-wood cellulose pulp fibre did not differ significantly from the tissue paper materials without non-wood cellulose pulp fibre.

    [0254] Multi-ply products were formed out of the tissue paper materials (basesheets with) the different non-wood fibre contents. The multi-ply products where three-ply products formed by nesting.

    [0255] Multi-ply product 1: G3A+G3A+G3Ai.e. 3 plies with 0% non-wood fibre, and fibre content by dry weight of the entire multi-ply product 1 is 0%.

    [0256] Multi-ply product 2: G3B+G3B+G3BI.e. 3 plies with 20% non-wood fibre, and fibre content by dry weight of the entire multi-ply product 2 is 20%.

    [0257] Multi-ply product 3: G3B+G3C+G3bi.e. 2 plies with 20% non-wood fibre and 1 ply with 50% non-wood fibre, giving a fibre content by dry weight of the entire multi-ply product 3 being 30%.

    [0258] Basis weight, thickness, tensile strength, softness panel and absorption were measured for the three multi-ply products. The results are indicated in the table in the below.

    TABLE-US-00013 Dry Dry Basis Thickness tensile tensile Straw weight 1 sheet MD CD GMT Softness Absorption content (g/m2) (mm) (N/m) (N/m) (N/m) panel (g/g) MP1 0% 55.2 0.71 623 234 382 4.4 9.2 MP2 20% 55.6 0.69 799 309 497 4.2 9.6 MP3 30% 56.5 0.73 695 252 418 4.3 9.6

    [0259] FIG. 3 is a diagram over the absorption values of the three different multi-ply products MP1, MP2, and MP3. As seen from the table and in FIG. 3, the absorption of the multi-ply tissue paper products including 20% or 30% by dry weight of the non-wood fibres were even better than the absorption of the multi-ply tissue paper product including no non-wood further. Also, as indicated in the table in the above, the multi-ply tissue paper products including non-wood fibres displayed values for dry tensile strength and softness which were comparable to that of the multi-ply tissue paper product including no non-wood fibre.

    [0260] In all, the results indicate that the multi-ply tissue paper products including non-wood fibres will display at least similar properties as the multi-ply tissue paper product including no non-wood fibre. Accordingly, the benefits obtained by using non-wood fibres may be obtained while still achieving a satisfactory tissue paper product.

    Example 4 Hybrid Tissue Paper Product

    [0261] Two-ply tissue paper products intended for use as kitchen towels were formed including one ply being produced with structured tissue technology and one ply being produced with CWP (Conventional Wet Pressed) technology.

    [0262] A reference two-ply tissue paper product (HYB1) including 0% non-wood fibres was formed from one tissue paper material ply produced by TAD technology being TP1 as described in Example 2 in the above, and one tissue paper material ply produced by CWP technology being G3-A as described in Example 3 in the above.

    [0263] A two-ply tissue paper product (HYB2) including 25% non-wood fibres was formed from one tissue paper material ply produced by TAD technology and including 30% by dry weight non-wood fibre being TP3 as described in example 2 in the above, and one tissue paper material ply produced by CWP technology including 20% by dry weight non-wood fibre, being G3-B as described in example 3 in the above.

    [0264] The two-ply tissue paper products were assembled by nesting.

    [0265] Basis weight, thickness, tensile strength, softness panel and absorption were measured for the three multi-ply products. The results are indicated in the table in the below.

    TABLE-US-00014 Dry Dry Basis Thickness tensile tensile Straw weight 1 sheet MD CD GMT Softness Absorption content (g/m2) (mm) (N/m) (N/m) (N/m) panel (g/g) HYB1 0% 40.4 0.73 503 270 368 4.6 13.3 HYB2 25% 39.0 0.75 456 309 375 4.4 13.9

    [0266] FIG. 4 is a diagram over the absorption values of the two two-ply tissue paper products HYB1 and HYB2. As seen from the table above and in FIG. 4, the absorption of the multi-ply tissue paper product including 25% by dry weight of the non-wood fibres was even better than the absorption of the multi-ply tissue paper product including no non-wood. Also, as indicated in the table in the above, the multi-ply tissue paper product including non-wood fibres displayed values for dry tensile strength and softness which were comparable to that of the multi-ply tissue paper product including no non-wood fibre.

    [0267] In all, the results indicate that the multi-ply tissue paper products including non-wood fibres will display at least similar properties as the multi-ply tissue paper product including no non-wood fibre. Accordingly, the benefits obtained by using non-wood fibres may be obtained while still achieving a satisfactory tissue paper product.

    Example 5-Varying Thickness

    [0268] Two-ply tissue paper products including two plies made by TAD technology and similar to 2P-1 and 2P-2, as obtained in the above Example 2, were used as a starting point.

    [0269] To vary the thickness of the two-ply products, the assembly of the two plies in each product was varied by varying the nip used when nesting the two plies together. Thus, one two-ply product with original thickness, one two-ply product with increased thickness, and one two-ply product with decreased thickness was formed for each of the qualities 2P-1 and 2P-2, as indicated in the above.

    [0270] Basis weight, thickness, tensile strength, softness panel and absorption were measured for the two two-ply products. The results are indicated in the table in the below.

    TABLE-US-00015 Dry Dry Basis Thickness tensile tensile Straw weight 1 sheet MD CD Softness Absorption content (g/m2) (mm) (N/m) (N/m) panel (g/g) 2P-1 0 42.5 0.71 707 507 5.0 13.3 Decreased thickness 2P-1 0 41.9 0.75 613 467 5.2 13.2 original 2P-1 0 43.3 0.79 608 430 5.2 13.0 Increased thickness 2P-2 30 40.5 0.73 513 488 4.6 14.3 Decreased thickness 2P-2 30 40.4 0.76 518 478 4.7 14.7 original 2P-2 30 40.2 0.82 462 421 4.5 14.7 Increased thickness

    [0271] The absorption over thickness achieved for the two qualities 2P-1 and 2P-2 are illustrated in FIG. 5.

    [0272] As may be seen in FIG. 5 and as indicated in the table above, the absorption of the two-ply paper tissue product 2P-2 including non-wood fibres is higher than the absorption the two-ply paper tissue product 2P-1 including no non-wood fibres for all of the various thicknesses.

    [0273] Further, the results indicate that the absorption results are stable to thickness variations.

    [0274] In all, the results indicate that the multi-ply tissue paper products including non-wood fibres will display at least similar properties as the multi-ply tissue paper product including no non-wood fibre. Accordingly, the benefits obtained by using non-wood fibres may be obtained while still achieving a satisfactory tissue paper product.

    [0275] Although the results in the above were achieved for specific examples of tissue paper materials and tissue paper products, the finding that the non-wood cellulose pulp fibres and the non-wood plies as described herein are indeed suitable for forming tissue paper materials and tissue paper products may be applied to a wide range of such materials and products.

    Definitions

    [0276] Tissue paper material: As tissue paper material we understand herein the one-ply base tissue as obtained from a tissue machine.

    [0277] 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.

    [0278] 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.

    [0279] 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.

    [0280] 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.

    [0281] 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.

    [0282] 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:

    [0283] 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.

    [0284] 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.

    [0285] 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.

    [0286] 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).

    [0287] 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.

    [0288] The structured tissue technology methods are known from prior art, for example TAD is known from U.S. Pat. No. 5,853,547; and ATMOS from U.S. Pat. Nos. 7,744,726, 7,550,061 and 7,527,709; and UCTAD from EP 1 156925 and WO 02/40774.

    [0289] 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.

    [0290] ATMOS technology is a production method developed by Voith and which is also well known to a person skilled in the art.

    [0291] 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 textured NTT technology may reduce the Yankee Hood drying load as compared to ATMOS.

    [0292] 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

    Lignin Content:

    [0293] 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 content-Method of acid hydrolysis 1), which includes: [0294] 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 [0295] ii) the measurement of soluble lignin (ASL: Acid Soluble Lignin), also described in the technical note Tappi UM2503. [0296] 3.1) Sample preparation: The samples were desintegrated 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. [0297] 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

    [0298] 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%. [0299] 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.Math.cm). Note 2: Detection limit (DL) ?0.1%

    [0300] 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

    [0301] 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,

    [0302] 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/DIS21437-Pulps: 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.

    [0303] 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

    [0304] Basis weight is determined in accordance with ISO 12625-6: 2016.

    [0305] The basis weight is determined in g/m.sup.2.

    Thickness Per Sheet:

    [0306] Thickness is determined in accordance with ISO 12625-3.

    GMT Strength:

    [0307] 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.

    [0308] The GMT strength is determined in accordance with ISO 12625-4.

    [0309] A load cell of 100N was used.

    Absorption:

    [0310] 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).

    [0311] Absorption was measured according to ISO12625-8:2011.

    [0312] The water is deionized water, conductivity?0.25 mS/m at 25? C., in accordance with ISO14487.

    Softness Panel:

    [0313] 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.

    [0314] The softer the product/tissue base sheet is rated the higher the value will be.

    [0315] Softness values of tissue paper products (finished goods) and tissue base sheets are not directly comparable as there are different scales/reference products.

    [0316] Each sample is composed of one product, i.e. a multi-ply tissue paper product.

    [0317] The dimensions of the samples are therefore the dimensions of the finished products.

    [0318] Samples are placed in MD before the panelists.

    [0319] Samples are conditioned for minimum 2 hours in a controlled area at 23? C. and 50% relative humidity.

    [0320] The different samples are comfort rated by ten panelists, and an average comfort rating for each product is determined over the panelists.

    [0321] Hence, softness panel values are comparative values within a test and indicate the perceived softness of a product.

    [0322] 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:

    [0323] Fibre length measurement was made using the standard for fibre analyser: ISO 16065-2:2014: Pulps-Determination of fibre length by automated optical analysisPart 1: Unpolarized light method.

    [0324] Length-weighted mean length was used and the average of the lengthweighted fibre-length distribution.

    Breaking Length Measurement

    [0325] 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.

    [0326] 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

    [0327] 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.

    [0328] It may be noted that the breaking length, as well as the average fibre length, are pulp characteristics. Thus the measurements 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.