Hygiene product

Abstract

The invention concerns a hygiene product comprising at least one layer of a nonwoven wherein the nonwoven layer comprises man-made cellulosic fibers wherein the layer or the layers has or have a rewet value of equal to or less than 30% and a liquid strike through time of equal to or less than 6 seconds for the use in disposable hygiene products, such as diapers, feminine pads and incontinence products or in wet wipes like toilet wipes, facial wipes, cosmetic wipes, baby wipes and sanitary wipes for cleaning and disinfection.

Claims

1. A hygiene product comprising at least one layer of a nonwoven wherein the at least one layer of the nonwoven comprises hydrophobic man-made cellulosic fibers, and wherein the layer or the layers has or have a rewet value of equal to or less than 30% and a liquid strike through time of equal to or less than 6 seconds.

2. The hygiene product according to claim 1, wherein the at least one layer of nonwoven fabric further comprises man-made cellulosic fibers and optionally a wetting agent.

3. The hygiene product according to claim 1 or 2, wherein the nonwoven fabric comprises a blend of 75 to 90% by mass of hydrophobic man-made cellulosic fibers and 25 to 10% by mass of man-made cellulosic fibers, provided that the total amount of the nonwoven fabric is 100% by mass.

4. The hygiene product according to claim 2, wherein the hydrophobic man-made cellulosic fibers are treated with a hydrophobic agent.

5. The hygiene product according to claim 4, wherein the hydrophobic agent is an alkyl ketene dimere.

6. The hygiene product according to claim 4 or 5, wherein the hydrophobic man-made cellulosic fibers contain the hydrophobic agent in an amount of 0.005 to 0.5% per mass.

7. The hygiene product according to claim 6, wherein the hydrophobic man-made cellulosic fibers contain the hydrophobic agent in an amount of 0.01 to 0.1% per mass.

8. The hygiene product according to claim 1 comprising two layers of nonwoven fabrics, wherein a first layer comprises hydrophobic man-made cellulosic fibers and a second layer comprises man-made cellulosic fibers.

9. The hygiene product according to claim 8, wherein the first layer is an airlaid, drylaid or wetlaid nonwoven.

10. The hygiene product according to claim 1, wherein the at least one layer is an airlaid, drylaid or wetlaid nonwoven.

11. The hygiene product according to claim 1, wherein the nonwoven is selected from the group consisting of a needle-punched, hydroentangled, thermal bonded or chemical bonded nonwoven or nonwoven web directly produced by a melt-blowing process employing a cellulose solution in N-methyl-morpholine-N-oxide (“NMMO”).

12. The hygiene product according to claim 1, wherein the hygiene product is a disposable hygiene product.

13. The hygiene product according to claim 1, wherein the hygiene product is a wet wipe.

14. The hygiene product according to claim 12, wherein the disposable hygiene product is selected from the group consisting of diapers, feminine pads and incontinence products.

15. The hygiene product according to claim 13, wherein the wet wipe is selected from the group consisting of toilet wipes, facial wipes, cosmetic wipes, baby wipes and sanitary wipes for cleaning and disinfection.

16. The hygiene product according to claim 8, wherein the first layer consists of 100% of hydrophobic man-made cellulosic fibers.

17. The hygiene product according to claim 8, wherein the first layer consists of a blend of 75 to 99.5% by mass of hydrophobic man-made cellulosic fibers and 0.5 to 25% by mass of man-made cellulose fibers provided that the total amount is 100% by mass.

18. The hygiene product according to claim 8, wherein the second layer consists of a thermobonded nonwoven of man-made cellulosic fiber and a thermoplastic material.

19. The hygiene product according to claim 18, wherein the thermobonded nonwoven consist of 50 to 90% by mass of man-made cellulosic fibers and 50 to 10% by mass of thermoplastic fibers provided that the total amount is 100% by mass.

20. The hygiene product according to claim 18 or 19, wherein the man-made cellulosic fiber has a modified cross-section, such as multilobal, irregular, triangular and hollow, preferred a trilobal man-made cellulosic fiber.

21. The hygiene product according to claim 18 or 19, wherein the man-made cellulosic fiber is a lyocell fiber.

22. The hygiene product according to claim 18 or 19, wherein the thermoplastic fiber, is a bicomponent fiber.

Description

EXAMPLE 1 (Comparison)

(1) 30 g/m.sup.2 carded, hydroentangled and apertured (medium mesh size) nonwoven fabrics were manufactured from 1.7 dtex dull hydrophobic viscose at different levels of the hydrophobic agent AKD 452 N (AKD 452 N is an alkyl-ketene-dimere-formulation commercially available from the company Kemira). Blends of the hydrophobic viscose with man-made cellulosic fibers were also tested. The inlet time and rewet values of the topsheets were tested according to the test methods described above.

(2) Table 1 shows that viscose fibers with a low concentration of hydrophobic treatment (sample 1.3, 1.4) have inlet time about the same value as the reference polyester (sample 1.1), but the rewet value is higher than desired for this application. With a higher concentration of the hydrophobic agent on the fiber, the inlet time is out of the range (sample 1.5). Also out of the range are the blends of hydrophobic man-made cellulosic fibers with man-made cellulosic fibers where the proportion of the hydrophobic man-made cellulosic fibers is higher than 25% (sample 1.6 and 1.7). A blend of 25% hydrophobic man-made cellulosic fibers with man-made cellulosic fibers shows a sufficient performance (sample 1.8).

(3) TABLE-US-00001 TABLE 1 Inlet time Sample Apertured nonwoven fabrics (s) Rewet (%) 1.1 Polyester (PET) (comparison) 4.0 7 1.2 Viscose (comparison) 5.0 64 1.3 Hydrophobic viscose at 0.005% AKD 4.4 51 1.4 90% Hydrophobic viscose at 4.8 47 0.01% AKD + 10% Tencel 1.5 Hydrophobic viscose at 0.05% AKD >20 Not determinable 1.6 75% hydrophobic viscose at >60 Not 0.1% AKD + 25% viscose determinable 1.7 75% hydrophobic viscose at >60 Not 0.1% AKD + 25% Tencel determinable 1.8 25% hydrophobic viscose at 6 30 0.1% AKD + 75% Tencel

EXAMPLE 2

(4) To improve the wettability of the hydrophobic fabrics and reduce the inlet time and rewet value, nonwoven fabrics made of hydrophobic viscose 1.7 dtex dull at 0.1% AKD 452N were additionally treated with a wetting agent (Plantacare 810 UP) from the company BASF. A 1.0% solution of the wetting agent “Plantacare 810 UP” (50% active substance) was made with distilled water and the pH was corrected to 5 with 30% citric acid solution. This solution was applied using a fine mist compressed air spray onto the upper surface of certain topsheets to a level of 1% active wetting agent by weight of topsheet. The samples were allowed to dry under ambient conditions overnight before testing. Inlet time and rewet values were tested on each fabric according to the test methods described above.

(5) It can be seen that nonwoven fabrics from blends of 75% hydrophobic viscose at 0.1% AKD 452N with 25% viscose fibers (sample 1.6) or with 25% Tencel fibers (sample 1.7) with an additional treatment of 1% of the wetting agent “Plantacare 810 UP” have significantly reduced the inlet time of the topsheets and the rewet values (samples 2.1 and 2.2).

(6) TABLE-US-00002 TABLE 2 Inlet time Rewet Sample Composition (sec) (%) 2.1 75% hydrophobic viscose at 0.1% 4.9 30 AKD + 25% viscose + wetting agent 2.2 75% hydrophobic viscose at 0.1% 5 30 AKD + 25% Tencel + wetting agent

(7) These fibers and fabrics can be used in different applications such as in wet wipes to achieve improved softness together with improved wettability and lotion management which are benefits for the end-users.

(8) Another object of the invention is to provide a nonwoven layer as an acquisition/distribution layer which significantly reduces the inlet time and rewet value in combination with topsheets.

(9) Surprisingly it has been found that the inlet time and rewet performance of topsheets is significantly improved when these topsheets are combined with a second layer of a thermobonded nonwoven fabric comprising man-made cellulosic fibers.

(10) The inventive hygiene product comprises two layers of nonwoven fabric and is characterised in that the first layer comprises a synthetic fiber or hydrophobic man-made cellulosic fiber and the second layer comprises a man-made cellulosic fiber.

(11) The first layer may consist of 100% of hydrophobic man-made cellulosic fiber or consist of blends of 75 to 99.5% by mass of hydrophobic man-made cellulosic fiber and 0.5 to 25% by mass of man-made cellulose fiber provided that the total amount is 100% by mass. The first layer can also be synthetic fibers like polyester.

(12) In a preferred embodiment the second layer consists of a thermobonded nonwoven of man-made cellulosic fiber and a thermoplastic material, wherein the thermobonded nonwoven consists of 50 to 90% by mass of man-made cellulosic fibers and 50 to 10% by mass of thermoplastic fibers provided that the total amount is 100% by mass.

(13) Appropriate for the thermobonded nonwoven are man-made cellulosic fibers with modified cross-sections, such as multilobal, irregular, triangular and hollow cross-sections.

(14) A preferred man-made cellulosic fiber for the use in the thermobonded nonwoven is a trilobal man-made cellulosic fiber. Such a fiber is available from Lenzing AG under the trademark “Viscostar”. The titer of this fiber is from 1.3 to 6.7 dtex, preferably 3 to 4 dtex. Another preferred man-made cellulosic fiber for the use in the thermobonded nonwoven is a lyocell fiber. The titer of the lyocell fiber is in the range of 0.9 to 9 dtex, preferably of 3.3. to 6.7 dtex. A lyocell fiber is available from Lenzing AG under the trademark “Tencel”. The staple length of both fiber types is from 4 to 90 mm, preferably 10 to 60 mm.

(15) The preferred thermoplastic fiber is a bicomponent fiber, for example a core-sheath PET/CoPET bicomponent fiber, a core-sheath PET/PE bicomponent fiber or a core-sheath-PE/PP bicomponent fiber.

(16) The layer is an airlaid, drylaid or wetlaid nonwoven, which can be made by those respective processes. All bonding processes are possible. The nonwoven is a needle-punched, hydroentangled, thermal bonded or chemical bonded nonwoven.

(17) A preferred nonwoven web is made by the “Lyocell melt-blown process” where the nonwoven web is directly produced by a melt-blowing process employing a cellulose solution in N-methyl-morpholine-N-oxide (“NMMO”) as laid open in WO 2007/124522.

(18) The nonwovens have a weight per unit area of between 5 to 100 g/m.sup.2, preferably 10 to 40 g/m.sup.2.

EXAMPLE 3

(19) 30 g/m.sup.2 nonwoven fabrics were manufactured from different fiber types and their blends through thermal bonding processes (through air bond) for use in an acquisition/distribution layer (ADL).

(20) Parallel-laid webs were made and the compressed webs were heated for 2 minutes at 150° C. to thermally bond the fabrics. The mean fabric area density was approximately 30 g/m.sup.2. The thermal bonded ADL layers made and tested were:

(21) A blend of 70% “Viscostar” trilobal viscose (3.3 dtex) and 30% bicomponent binder fiber (4 dtex, 50:50 concentric sheath-core polyethylene-polypropylene), used in samples 3.1, 3.3, 3.5 and 3.7.

(22) A blend of 70% Tencel 3.3 dtex and 30% bicomponent binder fiber (4 dtex, 50:50 concentric sheath-core polyethylene-polypropylene), used in samples 3.6 and 3.8.

(23) For these trials, 3 different apertured fabrics at 30 g/m.sup.2 were used for topsheets. A typical absorbent core was used and ADL nonwoven fabrics (30 g/m.sup.2) were placed between the topsheets and absorbent core. Inlet time and rewet was tested according to the test methods described below. The results of these trials are given in table 3.

Initial Testing of ADL Layers

(24) The inlet-rewet test used to assess the ADL was a further modified version of the method outlined in US 2007/0219517. Samples of topsheet, ADL and core material were cut to size and weighed.

(25) The components were laid on top of one another - with the topsheet uppermost, the ADL in the centre and the core at the bottom, then clamped in the test rig.

(26) The inlet time was measured as before with 4.0 ml of standard test liquid pipetted onto the top sheet from a height of 3 cm. The time was recorded from the initial release of the liquid to the moment all the liquid passed through or into the top sheet.

(27) The rewet was also measured as before, using a stack of ten 7 cm diameter Whatman 41 filter papers. However, after completion of the test the test sample was immediately disassembled and the three components were also weighed to calculate the distribution of the liquid through the sample. One test was performed with no ADL for comparison.

(28) TABLE-US-00003 TABLE 3 Inlet time Sample Top sheet (first layer) ADL (second layer) (sec) Rewet (%) 3.1 90% Hydrophobic viscose + 10% 70% Trilobal viscose 3.3 dtex + 4.3 20 Tencel (sample 1.4) 30% bicomponent fibers (thermal bond) 3.2 90% Hydrophobic viscose + 10% no ADL (comparison) 4.8 47 Tencel (sample 1.4) 3.3 Hydrophobic viscose (sample 1.5) 70% Trilobal viscose 3.3 dtex + 4.3 <1.5 30% bicomponent fibers (thermal bond) 3.4 Hydrophobic viscose (sample 1.5) no ADL (comparison) >20 Not determinable 3.5 Hydrophobic viscose at 0.01% 70% Trilobal viscose 3.3 dtex + 4.6 29 AKD 30% bicomponent fibers (thermal bond) 3.6 Hydrophobic viscose (sample 1.5) 70% Tencel 3.3 dtex + 30% 4.0 <1.5 bicomponent fibers (thermal bond) 3.7 Polyester 70% Trilobal viscose 3.3 dtex + 4.0 <1.0 30% bicomponent fibers (thermal bond) 3.8 Polyester 70% Tencel 3.3 dtex + 30% 4.0 <1.0 bicomponent fibers (thermal bond)

(29) It can be seen that the nonwoven fabrics made of 70% trilobal viscose or 70% lyocell fibers (Tencel) in blends with 30% bicomponent fibers processed through carding and thermal bonding improves significantly the rewet performance of the absorbent pads if it is used as an acquisition/distribution layer in a combination with topsheets made of hydrophobic man-made cellulosic fibers and also with polyester topsheets (sample 3.7 and 3.8).

(30) The inventive nonwoven fabrics are used in disposable hygiene products, like diapers, feminine pads and incontinence products. Hygiene products comprising one layer of a nonwoven fabric (a one layer nonwoven) which nonwoven fabric comprises a blend of man-made cellulosic fibers and hydrophobic man-made cellulosic fibers and which nonwoven is treated with a wetting agent are especially suited as wet wipes.