ABSORBENT FIBROUS WEB

Abstract

The present disclosure relates to an absorbent fibrous web, in which the fibres are constituted by cellulosic fibres including cellulosic staple fibres and cellulose pulp fibres and the absorbent fibrous web is a foam-formed hydro-entangled fibrous web. The present disclosure further relates to a method of manufacturing such an absorbent fibrous web.

Claims

1. An absorbent fibrous web, the fibres of the absorbent fibrous web being constituted by cellulosic fibres comprising cellulosic staple fibres and cellulose pulp fibres, wherein, the absorbent fibrous web is a foam-formed hydro-entangled fibrous web.

2. The absorbent fibrous web according to claim 1, wherein the cellulosic staple fibres are regenerated cellulosic fibres.

3. The absorbent fibrous web according to claim 1, wherein the cellulosic staple fibres and the cellulose pulp fibres are mixed with each other.

4. The absorbent fibrous web according to claim 1, wherein the cellulosic fibres located in a first surface layer have a similar fibre composition or a similar orientation of fibres as the cellulosic fibres located at a second surface layer being opposite to the first surface layer.

5. The absorbent fibrous web according to claim 1, wherein the cellulosic staple fibres have a length in the range of 2-25 mm.

6. The absorbent fibrous web according to claim 1, wherein the cellulosic staple fibres have a linear density within the range of 0.3-3 dtex.

7. The absorbent fibrous web according to claim 1, wherein the cellulosic staple fibres make up in the range of 2-50% of a total weight of the cellulosic fibres.

8. The absorbent fibrous web according to claim 1, wherein the cellulose pulp fibres make up in the range of 50-98% of a total weight of the cellulosic fibres.

9. The absorbent fibrous web according to claim 1, having a basis weight in the range of 10-250 gsm.

10. The absorbent fibrous web according to claim 1, wherein the absorbent fibrous web is micro-embossed.

11. The absorbent fibrous web according to claim 1, having a TS7 Softness value of less than 25 as measured with the TSA method described herein.

12. The absorbent fibrous web according to claim 1, having a TS750 Roughness value of less than 40 as measured with the TSA method described herein.

13. The absorbent fibrous web according to claim 1, having a Wetting Time, as measured with the MMT method described herein, taken as an average for both surfaces of the absorbent fibrous web and as an average of top and bottom, of less than 2.3 s.

14. The absorbent fibrous web according to claim 1, having a Spreading Speed, as measured with the MMT method described herein, taken as an average for both surfaces of the absorbent fibrous web and as an average of top and bottom, of over 6 mm/s.

15. The absorbent fibrous web according to claim 1, having an Absorption Time of less than 1.0 s as measured with the AWR method described herein.

16. The absorbent fibrous web according to claim 1, having a Water Spreading Length in a machine direction of the absorbent fibrous web of at least 60 mm as measured with the AWR method described herein.

17. The absorbent fibrous web according to claim 1, having an Air Permeability of at least 800 mm/s as measured with the method described herein.

18. A method of wiping with the absorbent fibrous web according to claim 1, wherein the absorbent fibrous web is one of a hand wiping material, a hygiene tissue and a layer in an absorbent article for absorption of a body fluid.

19. A method of manufacturing an absorbent fibrous web according to claim 1, wherein the method comprises: foam-forming a mixture of cellulosic fibres, the cellulosic fibres comprising cellulosic staple fibres and cellulose pulp fibres, two-sided dewatering of the mixture to form an intermediate web, and hydro-entangling the intermediate web.

20. The method according to claim 19 further comprising micro-embossing on at least one surface of the absorbent fibrous web.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0122] The absorbent fibrous web as disclosed herein will hereinafter be further explained by means of non-limiting examples with reference to the appended figures wherein:

[0123] FIG. 1a-b are microscope photos of Sample A, made of an absorbent fibrous web as described herein;

[0124] FIG. 2a-b are microscope photos of Sample B, made of an absorbent fibrous web as described herein;

[0125] FIG. 3a-b are microscope photos of Sample C, a 2-ply tissue product according to prior art; and

[0126] FIG. 4a-b are microscope photos of Sample D, another 2-ply tissue product according to prior art.

DETAILED DESCRIPTION

[0127] In order to compare products made with the absorbent fibrous web as described herein comparisons were made between different materials suitable for handwiping.

[0128] The following samples were compared to each other:

[0129] Sample A:

[0130] A foam-formed and hydroentangled absorbent fibrous web material as described herein. Grammage 45.5 gsm. The fibres were 15% viscose, commercial 1.7 dtex 10 mm Danufil, Kelheim, and 85% unrefined bleached softwood kraft pulp. The material has also been micro-embossed with a pattern having 80 dots/cm.sup.2. Please see FIGS. 1a and 1b, wherein FIG. 1a shows the side facing the hydroentangling jets and FIG. 1b shows the side facing the hydroentangling fabric. Hydroentangling was made with 294 kWh/t at a machine speed of 10 m/min.

[0131] Sample B:

[0132] A foam-formed and hydroentangled absorbent fibrous web material as described herein. 30 Grammage 58.8 gsm. The fibres were 17% viscose, commercial 0.9 dtex 8 mm Danufil, Kelheim, and 83% RaumaCell Biobright TCF from UPM Kymmene. The material has also been micro-embossed with a pattern having 80 dots/cm.sup.2. Please see FIGS. 2a and 2b, wherein FIG. 2a shows the side facing the hydroentangling jets and FIG. 2b shows the side facing the hydroentangling fabric. Hydroentangling was made with 147 kWh/t at a machine speed of 139 m/min.

[0133] Sample C:

[0134] A hand towel being on the market: Tork Xpress® Extra Soft Multifold Hand Towel Premium, art no 100297, a 2-ply tissue hand towel. For the tested samples, the first ply (having a pink décor) had a basis weight of 20.7±0.1 gsm and the second ply 20.8±0.2 gsm. Please see FIGS. 3a and 3b, wherein FIG. 3a shows the décor side and FIG. 3b shows the opposite side. Both plies are made of structured tissue paper and comprise a wet strength agent but no softener. The fibres are virgin pulp fibres. The term “structured tissue paper” as used herein denotes a tissue paper having a three-dimensional structure, such as tissue paper manufactured with TAD or ATMOS™ technology.

[0135] Sample D:

[0136] A hand towel being on the market: Tork Xpress® Soft Multi-fold Hand Towel Premium, art no 100288, the adhesive of the décor-embossing has a blue colour. One ply is a structured tissue paper 21.1±0.1 gsm and the other ply is a dry-crepe tissue paper 23.5±0.1 gsm. Please see FIGS. 4a and 4b, wherein FIG. 4a shows the decor-embossed side, i.e. the structured tissue paper side, and FIG. 4b shows the opposite side, i.e. the dry-crepe tissue paper side. Both plies comprise a wet strength agent but no softener. The fibres are virgin pulp fibres.

[0137] The photos shown in FIGS. 1a-4b have all been taken in a microscope using the same magnification, such that the image shown corresponds to a region of 17.5×13 millimetres in the sample.

[0138] Table 1 below describes some of the characterizing properties of Samples A-D, please see columns 3-6. The values after ±show the standard deviation.

[0139] In addition, comparisons have been made for some of the parameters to the intermediate web of Sample A, i.e. the absorbent fibrous web as is without any hydroentangling or micro-embossing, please see column 1 of Table 1 below.

[0140] Further, comparisons were made for some of the parameters to the absorbent fibrous web of Sample A, hydroentangled but without any micro-embossing, please see column 2 of the Table 1 below.

TABLE-US-00001 TABLE 1 Column 1 2 3 4 5 6 Name A (raw) A (raw + Sample Sample Sample Sample hydroent A B C D angled) Photo 1a-b 2a-b 3a-b 4a-b Grammage (g/m.sup.2) 48.7 ± 0.8  47.8 ± 0.7  45.5 ± 0.4  58.8 ± 1.1  41.6 ± 0.4  44.7 ± 0.2  Bulk (cm.sup.3/g) 5.9 10.6 ± 0.1  10.4 ± 0.2  7.5 ± 0.1 9.8 ± 0.3 8.4 ± 0.3 0.7 Air Permeability 650 ± 10  2317 ± 31  1917 ± 42  1160 ± 42  520 ± 13  237 ± 4  @200Pa 20cm.sup.2 (mm/s) Wetting Time (s)—MMT  2.6 ± 0.17  1.9 ± 0.13  1.9 ± 0.14  2.1 ± 0.16  2.5 ± 0.61  2.1 ± 0.14 Spreading Speed  5.3 ± 0.28 10.3 ± 0.53 10.7 ± 0.72  8.3 ± 0.33  7.7 ± 0.80  9.0 ± 0.58 (mm/s)—MMT TS7 Softness—TSA 22.9 ± 1.8  17.6 ± 1.4  13.7 ± 0.6  16.4 ± 2.0  25.5 ± 2.4  27.2 ± 4.1  TS750 Roughness— 35.1 ± 7.4  19.9 ± 2.7  18.8 ± 3.4  39.2 ± 6.3  38.8 ± 5.2  42.6 ± 5.8  TSA Absorption Time (s)— 0.87 ± 0.12 0.45 ± 0.06 0.65 ± 0.12 1.08 ± 0.08 AWR Water Spreading  87 ± 4.1  68 ± 7.7  59 ± 2.5  59 ± 4.8 Length MD (mm)— AWR Rewet (g)—AWR 0.31 ± 0.01 0.24 ± 0.01  0.34 ± 0.005 0.34 ± 0.01 Panel: handled dry 5.69 5.28 3.97 3.53 Panel: hand wiping 5.03 5.61 4.36 3.89 experience”

[0141] When comparing the two left-hand columns, it may be seen that the step of hydroentangling increased the Air Permeability about 3.6 times. The Bulk and the Spreading Speed were almost doubled. The hydroentangling also had a positive influence on the TS7 and TS750 values as measured with the TSA method described herein.

[0142] When looking at Samples A-D, it can be seen that there is a huge difference in Air Permeability when comparing Samples A and B, made of absorbent fibrous webs as disclosed herein, to Samples C and D, which are hand towels available on the market. The absorbent fibrous web as disclosed herein may have an Air Permeability of at least 800 mm/s, such as at least 1000 mm/s, at least 1500 mm/s, at least 1800 mm/s. Please note that all Air Permeability measurements have been made for samples like the photos in FIGS. 1a-4b. There are thus no deliberately made apertures in the tested materials. Please see also the method description above.

[0143] The hand feel of Samples A-D were tested by means of the TSA method described herein. As may be seen for both TS7 Softness and TS750 Roughness, Samples A and B have much lower values than Samples C and D, indicating a softer and more textile-like material. The absorbent fibrous web as disclosed herein may have a TS7 Softness value of less than 25, such as less than 20 or less than 18. The absorbent fibrous web as disclosed herein may have a TS750 Roughness value of less than 40, such as less than 30, less than 25, or less than 20.

[0144] The absorbent fibrous web as disclosed herein may have a Wetting Time, as measured with the MMT method described herein, taken as an average for both surfaces of the absorbent fibrous web, i.e. an average of the five samples mentioned above, and as an average of top and bottom, of less than 2.3 s, such as less than 2.2 s, less than 2.1 s, or less than 2.0 s. Also for this parameter, the hydroentangling influences the value as may be seen when comparing columns 1 and 2.

[0145] The absorbent fibrous web as disclosed herein may have a Spreading Speed, as measured with the MMT method described herein, taken as an average for both surfaces of the absorbent fibrous web and as an average of top and bottom, of over 6 mm/s, such as in the range of 6-18 mm/s, 8-16 mm/s or 10-15 mm/s. As may be seen when comparing columns 1 and 2, the hydroentangling has a huge influence on the Spreading Speed.

[0146] The parameters Absorption Time, Water Spreading Length MD and Rewet were tested with the AWR method as described above. Thereby Sample A and B were measured with the hydroentangled side upwards and Samples C and D were measured with the décor side upwards, meaning that the testing liquid was applied to this side. Please see also FIGS. 1a, 2a, 3a and 4a. Sample A has a significantly shorter absorption time than Sample D. Further, Samples A and B have a higher Water Spreading Length MD than Samples C and D. All samples spread the testing liquid all the way to the side edge in CD, and would have spread further if possible. Hence, the CD values are not included in Table 1.

[0147] The absorbent fibrous web as disclosed herein may have an Absorption Time of less than 1.0 s, such as less than 0.9 s, as measured with the AWR method described herein, please see method description above.

[0148] The absorbent fibrous web as disclosed herein may have a Water Spreading Length in the machine direction, MD, of the absorbent fibrous web of at least 60 mm, such as at least 70 mm or at least 80 mm. Please see also the method description of the AWR method above.

[0149] Samples A-D were also tested in a panel test involving 36 persons in a dry state and used for hand wiping. Please, see the method description above and the data of the two lowermost rows of Table 1.

[0150] As may be seen, Samples A and B scored significantly better than Samples C and D when handled dry. Further, Sample C scored better than Sample D. These results correlate well with the results of the TSA-method.

[0151] Samples A and B also scored significantly better than Samples C and D when used for hand wiping. Sample B scored better than Sample A, which is believed to be an effect of the higher grammage. Further, Sample C scored better than Sample D.

[0152] Table 2 illustrates, with another example, the huge influence the hydro-entangling step has on the air permeability and the bulk. Both materials of Table 2 were foam-formed of the same fibre composition, 15% lyocell, 1.4 dtex 10 mm from Lenzing and 85% International Paper Supersoft pulp. The material to the left was manufactured at a machine speed of 94 m/min, but without any hydroentangling. The material to the right was manufactured at a machine speed of 91 m/min with hydroentangling energy of 232 kWh/t. None of the materials were micro-embossed.

TABLE-US-00002 TABLE 2 Material without Material with hydroentangling hydroentangling Grammage (g/m.sup.2) 47.0 ± 0.5  43.8 ± 1.2 Bulk (cm.sup.3/g)  7.8 ± 0.7  14.3 ± 0.4 Air permeability  830 ± 64 3350 ± 103 @ 200Pa 20 cm.sup.2 (mm/s)

[0153] As may be seen from the data of Table 2, the bulk almost doubled for the hydro-entangled material, while air permeability increased 4 times. In general terms, the step of hydroentangling may at least double, such as triple or quadruple, the air permeability.

[0154] Further modifications of the absorbent fibrous web within the scope of the appended claims are feasible. As such, the present disclosure should not be considered as limited by the embodiments and figures described herein. Rather, the full scope of the disclosure should be determined by the appended claims, with reference to the description and figures.