LIQUID-IMPREGNATED NONWOVEN FABRIC WHICH CONTAINS ZINC OXIDE-CONTAINING CELLULOSE FIBERS

Abstract

The present invention relates to a formed fabric which contains cellulose fibers, which contain zinc oxide particles which are at least partially incorporated and which is additionally impregnated with a liquid, and to a method of its production and to its use, in particular for manufacturing preservative-free, moist wet wipes.

Claims

1. A formed fabric comprising cellulose fibers, wherein the cellulose fibers comprise incorporated zinc oxide particles at least partially and wherein the formed fabric is additionally impregnated with a liquid.

2. The formed fabric according to claim 1, wherein the liquid has a pH less than 7.

3. The formed fabric according to claim 2, wherein the liquid has a pH between 3 and 6.

4. The formed fabric according to claim 2, wherein the liquid comprises an organic or inorganic acid which forms zinc salts which have a solubility of more than 50 ppm in 18-MOhm water at 25° C. and an atmospheric pressure of 1013 hPa.

5. The formed fabric according to claim 1, wherein the zinc-oxide-incorporated cellulose fibers comprise between 0.1 and 10 wt % zinc oxide relative to absolutely dry cellulose.

6. The formed fabric according to claim 1, wherein the zinc oxide particles are coated with a synthetically produced polymer.

7. The formed fabric according to claim 1, further comprising zinc-oxide-free cellulose fibers.

8. The formed fabric according to claim 1, further comprising synthetic fibers aside.

9. The formed fabric according to claim 1, wherein the cellulose fibers are selected from the group consisting of staple fibers and endless filament fibers.

10. The formed fabric according to claim 1, wherein said fiber has a fiber-fiber friction of 8.5 N or higher measured with the sledge test.

11. A method for the manufacturing of a formed fabric by traditional fleece manufacturing methods, comprising providing cellulose fibers which comprise incorporated zinc oxide, wherein the cellulose of fibers form fleece and that the formed fabric is impregnated with a liquid.

12. A moist wet wipe comprising a formed fabric which comprises zinc-oxide-incorporated cellulose fibers, wherein said wipe is impregnated with a liquid.

13. The wipe according to claim 12, wherein the wipe comprises no additional preservative agents.

14. A moist face mask comprising a formed fabric which comprises zinc-oxide-incorporated cellulose fibers, wherein said mask is impregnated with a liquid and wherein said mask has skin-caring action.

15. The formed fabric according to claim 3, wherein the liquid has a pH between 4.0 and 5.5.

16. The formed fabric according to claim 5, wherein the zinc-oxide-incorporated cellulose fibers comprise between 0.3 and 4.5 wt % zinc oxide relative to absolutely dry cellulose.

17. The formed fabric according to claim 16, wherein the zinc-oxide-incorporated cellulose fibers comprise between 0.3 and 3.5 wt % zinc oxide relative to absolutely dry cellulose.

18. The formed fabric according to claim 6, wherein the synthetically produced polymer is polyacrylate.

Description

DESCRIPTION OF THE INVENTION

[0016] The solution of the above-described problem consists in making a formed fabric available which contains cellulose fibers, wherein the cellulose fibers contain incorporated zinc oxide particles at least partially and the formed fabric is additionally impregnated with a liquid. The cellulose fibers containing zinc oxide are according to the invention cellulosic artificial fibers, manufactured, e.g. according to the viscose-, modal- or lyocell method, which are basically known to the person skilled in the art. Even the spinning in of solid substances into such fibers is basically known to the person skilled in the art, for example from WO 2011/026159 for viscose spinning solutions or from WO 2007/022552 for lyocell spinning solutions. In addition to other advantages, the formed fabric according to the invention also has anti-allergenic properties on account of the enzyme-deactivating properties of ZnO as well as the absorption of allergenic substances. Another surprising advantages of the present invention is the fact that these properties are achieved here with considerably lesser ZnO contents than is possible according to the prior art (see also the examples described below and table 2).

[0017] A formed fabric is preferred in which the liquid has a pH lesser than 7. A formed fabric is especially preferred in which the liquid has a pH between 3 and 6, preferably between 4.5 and 5.5. This is achieved by impregnating the formed fabric with an acidic liquid with an appropriate pH. A preferred embodiment of the present invention is therefore a formed fabric in which the liquid contains an organic or inorganic acid which forms a soluble zinc salt. For the purposes of this invention the term soluble zinc salt should denote a zinc salt which has a solubility of more than 50 ppm in 18-MOhm water at 25° C. and an atmospheric pressure of 1013 hPa. The term “18-MOhm water” generally denotes a water deionized by ion exchangers or other known methods which has a conductivity of a maximum of 18 MOhm.

[0018] This acid should be already widely used in cosmetics. This acid is preferably selected from the group containing formic acid, acetic acid, lactic acid, citric acid, gluconic acid, glutamic acid, succinic acid, hydrochloric acid, and sulfuric acid and the soluble zinc salt is accordingly preferably selected from the group containing zinc formiate, zinc acetate, zinc lactate, zinc citrate, zinc gluconate, zinc glutamate, zinc succinate, zinc chloride and zinc sulfate.

[0019] The zinc-oxide-incorporated cellulose fibers in the formed fabric of the invention contain between 0.1 and 10 wt % zinc oxide, preferably between 0.3 and 4.5 wt % zinc oxide, in particular preferably between 0.3 and 3.5 wt % zinc oxide relative to absolutely dry cellulose. Even up to 17 wt % zinc oxide is possible but is not frequently used due to economic considerations.

[0020] The formed fabric according to the invention can also contain zinc-oxide-free cellulose fibers aside from the zinc-oxide-incorporated cellulose fibers. For this, even natural cellulose fibers such as cotton, hemp, etc. can be considered in addition to the artificial cellulosic fibers manufactured, e.g. according to the viscose-, modal- or lyocell method.

[0021] The formed fabric according to the invention can also contain synthetic fibers aside from the zinc-oxide-incorporated cellulose fibers. Basically all known synthetic fibers can be considered for this. Polyethylene terephthalate and polypropylene are especially suitable.

[0022] In the formed fabric according to the invention the cellulose fibers are either staple fibers or endless filament fibers. The formed fabrics consisting of endless filament fibers can also comprise the formed fabrics manufactured according to the melt-blown method (see, for example, EP 1093536 B1).

[0023] The formed fabric according to the invention has a fiber roughness of 8.5 N or greater—measured with the sledge test described in the examples. It was found that a higher fiber roughness leads to a better cleaning action, among other things also by raising the cleaning surface of the moist wet wipe.

[0024] The present invention also has as subject matter a method for the manufacturing of a formed fabric by traditional fleece manufacturing methods in which cellulose fibers containing incorporated zinc oxide are used for the fleece formation and the formed fabric is impregnated with a liquid. Fleece formation methods which can be considered include mechanical fleece formation, hydrodynamic fleece formation, aerodynamic fleece formation and melt blowing; fleece strengthening methods which can be considered include above all water jet strengthening, needling, thermal strengthening and chemical strengthening.

[0025] The present invention furthermore has as subject matter the use of a formed fabric which contains zinc-oxide-incorporated cellulose fibers and is impregnated with a liquid for the manufacture of wet wipes, in particular as baby moist wipes, makeup removal cloths, cleaning cloths, etc.

[0026] A usage in accordance with the invention is especially preferred in which the wet wipes contain no additional preservative agents. The concept “preservative agents” denotes here the substances listed in Annex VI of the EU Cosmetics Regulation (76/768/EEC), status 03. September 2014.

[0027] Therefore, the present invention also comprises wet wipes which contain the above-described formed fabric in accordance with the invention and therefore do not require such additional preservative agents.

[0028] An improved cleaning power also occurs by the absorption of anionic dirt (e.g. feces, organic acids, etc.) on ZnO on the surface and in the cross section of the fibers.

[0029] The present invention furthermore has as subject matter the use of a formed fabric which contains zinc-oxide-incorporated cellulose fibers and is impregnated with a liquid for the manufacture of moist face masks. Such moist fact masks can be impregnated with substances which have a skin-caring action The ZnO itself, incorporated into the fiber and which is known for its skin-caring action, also contributes to the skin-caring action of the entire product.

[0030] The invention is described in the following using examples. However, the invention is expressly not limited to these examples but rather also comprises all other embodiments based on the same inventive concept.

EXAMPLES

Manufacture of the Wet Wipes:

[0031] At first, lyocell fibers were manufactured according to the lyocell method known in the prior art, into which 0.0, 1.2, 3.0 and 16.7 wt % (relative to absolutely dry fiber) ZnO were spun so that a spinning mass according to the lyocell process was produced which contained 13 wt % cellulose and the above-cited amount of ZnO (relative to cellulose). This was then spun according to the lyocell process (individual fiber titer 2.5 dtex, cut length 38 mm), provided with a finish which has no preservative or biocidal properties and then dried. Needle fleeces (surface weight 60 g/m.sup.2, 300 punctures/cm.sup.2) were produced from the fibers manufactured in this manner which were subsequently strengthened with a water jet and then dried (on a Fleissner system with the following settings: 35 bar water pressure; 1 jet beam with 2 nozzle rows; demineralized water: pH 7.6; passage speed of the fleece 2 m/min; 100 μm perforation diameter of the water jet nozzles; 118° C. drying temperature. The fleeces manufactured in this manner were impregnated with 290 wt % lotion (relative to the dry weight of the fleece) in order to obtain corresponding baby wet wipes. The exact composition of the lotion is indicated in table 1. The pH of the lotion was adjusted after 48 h of contact with the formed fabrics to pH 3.00.

TABLE-US-00001 TABLE 1 INCI name Trade name Manufacturer Function wt % Aqua Demineralized Itself Solvent 96.15 g water Propylene glycol Propylene Sigma Moisture retention  3.00 g glycol Aldrich agent Polysorbate 20 Tween 20 Sigma Solutizer 0.60 Aldrich Capryl/capramidopropyl Tego betain Evonik Surfactant 0.25 betaines 35% 810 Acetic acid Acetic acid Sigma pH adjustment 1.44 pA Aldrich

Test for Sufficient Preservation According to ISO 11930:

[0032] Every 100 wet wipes, consisting of fibers with 0.0, 1.2 or 16.7 wt % ZnO with the size 15×10 cm, were impregnated with lotion (290 wt % lotion on dry weight of fleece, composition according to table 1) and then the tests for sufficient preservation were carried out. To this end the wet wipes were injected with an inoculum which contained germs customary in cosmetics in a defined concentration (S. aureus: 7.40E+05 KBE; P. aeruginosa: 2.80E+05 KBE; E. coli: 4.40E+05 KBE; C. albican: 6.90E+05 KBE; A. brasiliensis: 1.70E+05 KBE). After the injection the wet wipes were stored 28 days. After an observation time of 7, 14 and 28 days the germ count of the microorganisms on the wet wipes was determined (see table 2) in order to be able to determine a reduction of germs.

[0033] The tests according to ISO 11930 showed that the preservation regarding the germs customary in cosmetics was successful for the wet wipes with 1.2 and 16.7 wt % ZnO on absolutely dry fibers since a sufficient germ reduction was achieved. The higher amount of ZnO clearly showed a better action (criterion A according to DIN EN 11930) than the lesser concentration of ZnO (criterion B according to DIN EN 11930).

Sleds Test According to EN 1202 PPS:

[0034] The softness of the fibers was determined with the sledge test described in EN 1202 PPS. The essential conditions of this test are:

[0035] 5 g fiber sample were carded twice, for example, on a Uster MTDA-3 rotor ring device. The fibers were conditioned for at least 24 h according to the EDANA regulation (ERT 60.2-99 and then cut by a template. The material is subsequently placed in the test device and a carriage carrying a weight of 2000 g is mounted and placed on the sample. The test is started and after 10 sec the force is measured that is necessary to draw the carriage over the sample. The softer the fiber surface is, the less force is required to draw the carriage forward. The test was repeated four times on each material. The results are shown in the following table 3.

TABLE-US-00002 TABLE 2 ZnO content of the Observation Germs fibers/ time period S. aureus P. aeruginosa E. coli: C. albicans: A. brasiliensis: wt % [Days] KBE/g KBE/g KBE/g KBE/g KBE/g Result 0.0 7 20 <10 <10 9.4 × 10E3 — Neither 14 <10 <10 <10 3.0 × 10E5 <10 criterion A 28 <10 <10 <10 <10 <10 nor B met on account of insufficient germ reduction. Product displays optically dark spots. 1.2 7 <10 <10 <10 3.0 × 10E5 — Meets 14 <10 <10 <10 3.1 × 10E4 <10 criterion B 28 <10 <10 <10 40 <10 according to DIN EN 11930 16.7 7 <10 <10 <10 1.5 × 10E5 — Meets 14 <10 <10 <10 1.5 × 10E5 3.3 × 10E4 criterion A 28 <10 <10 <10 2.0 × 10E4 4.8 × 10E4 according to DIN EN 11930

TABLE-US-00003 TABLE 3 Fiber-fiber friction Standard (average value) deviation Sample name [N] [N] 3.0 wt % ZnO 9.23 0.25 1.2 wt % ZnO 6.86 0.14