AT513349A2 - Nonwovens with hydrophobic cellulosic man-made fibers - Google Patents

Abstract

The invention relates to a nonwoven comprising a mixture of two types of fiber, the first type of fiber being a cellulosic fiber and the second type of fiber being a biodegradable hydrophobic cellulosic fiber, characterized in that the absorbency of a liquid is compared to that of a nonwoven fabric highest absorbency for this liquid comprising only one of the fiber types is at least 5% higher.

Description

PL0534 Μ · * * * * * * * · · · · · · · · · · · · • • • • • •. · Φ Φ ΦΦ ΦΦ Φ ΦΦ ΦΦ Φ

Nonwovens with hydrophilic celiulosic man-made fibers

The invention relates to a fleece of a mixture of hydrophilic celiulosischen fibers and celiulosischen fibers. 5

Cellulosic man-made fibers such as viscose and lyocell fibers are best known for their water absorption behavior and are used in cases where hydrophilicity is required. In contrast, synthetic fibers such as polyester, polyethylene, and polypropylene are inherently hydrophobic, meaning that they do not absorb water into their internal structure.

Viscose and lyoceli fibers known in the prior art are hydrophilic and, depending on the type of applied finish, have a surface tension of about 85-90 mN / m. For polyester fibers, which are used for nonwoven applications, this is in the range of 15 40 - 45 mN / m. i

Viscose and modal type cellulosic fibers are produced according to the viscose process. Such fibers were given the generic names viscose and modal by BISFA (International Bureau for the Standardization of Man-Made Fibers). 20

In recent years, the " amine oxide process " or " lyocell method " as an alternative to the viscose process, wherein cellulose, without forming a derivative, in an organic solvent of an amine oxide, in particular N-methylmorpholine-N-oxide (NMMO), is dissolved. Cellulosic fibers made from such solutions are referred to as " solvent spun " Fibers, were given the generic name Lyocell by BISFA (International Bureau for the Standardization of Man-Made Fibers) and can be obtained from Lenzing AG under the brand TENCEL®.

Other man-made cellulose fibers can be made using chemical techniques (e.g., the copper-ammonium process) or using other direct solvents, such as ionic liquids.

Wet wipes for hygiene applications, such as towelettes, facial tissues, baby wipes and sanitary wipes are made of nonwovens which are soaked in lotion. Lotions are 35 low to medium viscosity aqueous or aqueous-alcoholic substances intended for use on the skin, or aqueous or aqueous-alcoholic suspended or emulsified substances. Household Wipers PL0534 «L * II · Μ * · φ · · · · · · · · · · · · · · · · · · · · · · · · · · · φ · φ φ ·· ΦΦ · Φφ ΦΦ Φ or in the industry also use a wide variety of fluids to enhance their effectiveness. For nonwoven applications, synthetic fibers such as polyesters are widely used because they improve bulk, opacity, and softness in nonwoven and textile applications.

The prior art is a blend of man-made cellulose fibers and polyester fibers to improve the performance of the product in wipes, 10 hygiene applications or technical applications. Fabrics made from 100% cellulosic material have only a slight hydrophobic / nonpolar effect.

For ecological reasons, there is a need for nonwovens that are made from renewable resources and that are also biodegradable and good

Absorption properties for liquids, for example, for lotions, have.

Hydrophilic cellulosic fibers such as conventional lyocell fibers are in the range of 8.5-9 g water / g nonwoven, while hydrophobic fibers such as polyester or hydrophobic lyocell · 20 fibers show little to no absorbency (0-1.0 g / g) ,

Now, one would expect that any mixture of hydrophilic cellulosic fibers with hydrophobic fibers following a linear function would be in a range between these values, 25

It has been found that a nonwoven comprising blends of hydrophilic cellulosic fibers with conventional cellulosic fibers has a higher liquid absorbency than a nonwoven comprising only conventional cellulosic fibers or hydrophobic fibers. 30

The nonwoven fabric of the present invention comprises a blend of two types of fibers, the first type being a cellulosic fiber and the second type being a biodegradable hydrophobic cellulosic fiber and characterized by having a liquid absorbency compared to a highest absorbency nonwoven fabric this liquid, which comprises only one of these fiber types, is at least 5% higher. Depending on the mixture, the absorption capacity can increase by up to 15% or more. PL0534 * ·····% * ** ** · • • • • • • · · · · · · · · · · · · · · # ♦ «· ·» * ♦ · * »·· *

Liquids are, for example, lotions (usually containing water, glycols such as propylene glycol, organic acids such as benzoic acid, dehydroacetic acid, citric acid, salts of organic acids such as sodium citrate, emulsifiers such as polysorbate 20 and other ingredients), other liquids are oils.

It has also been found that the increase in absorbency also depends on the surface tension of the liquid. For liquids with a surface tension above 50 mN / m, for example water, the mixture comprises 5 to 40% by weight of fibers of the second fiber type (hydrophobic fibers ), and 95 to 60% by weight of the first fiber type (hydrophilic fibers), preferably 5 to 30% by weight of the second fiber type and 95 to 70% by weight of the first fiber type, totaling 100%. For liquids having a surface tension below 50 mN / m, for example alcohols, the mixture comprises 40 to 95% by weight of second fiber type fibers (hydrophobic fibers) and 60 to 5% by weight of the first fiber type (hydrophilic fibers), preferably 30 to 95 wt .-% of the second fiber type and 70 to 5 wt .-% of the first fiber type, a total of 100%. 20

The first and second fiber types are a man-made cellulosic fiber, usually selected from the group consisting of viscose fibers, lyocell fibers or modal fibers. The first and second fiber types may also be a cellulosic natural fiber, for example cotton. 25

The production of hydrophobic cellulosic fibers is described in the not yet published application AT-A1658 / 2011 of Lenzing AG.

The water repellents, for example, alkyl ketene dimer formulations (AKD-30 formulations), are commercially available (for example, Krorira sold Hydrores® compounds). The most common are formulations with about 5 - 25% active ingredient content. In this example, the formulation is an acidic emulsion having about 20-22% active ingredient content. The hydrophobic fibers contain the hydrophobing agent in an amount of from 0.01 to 1% by weight, preferably from 0.05 to 0.2% by weight, based on cellulose. The preferred hydrophobizing agent is an alkylene dimer. PL0534 Μ ···· • * * * ··· »· · · · · · · · · · · ·« · · * + · Φ * · «* · +

Preparation of Hydrophobic Cellulose Fibers Used in the Examples 1000 g of never-dried lyocell (1.7 dtex / 38 mm) fibers were wet-stripped from the Lyocel® production line before addition of a finish and pressed to a moisture content of about 50% Solution containing 41 g Alkylketendimeriösung (13 g / l with 21% active ingredient) (eg, commercially available from Kemira OY1 Hydrores®) treated at about 60 ° C for 5 minutes and dried to a moisture content of about 10%.

These fibers have a water retention of about 55-75%, more usually in the range of 60-65%, that is about 20% under conventional Tencel (1,7 / 38) fibers (85-90%).

These fibers were used to make hydroentangled samples at about 60 g / m 2, blending commercially available glossy Tencel (1.7 / 38 mm) nonwoven fibers with commercially available Lenzing NW 1.7 dtex / 40mm glossy viscose fibers.

Viiesherstellunq

The patterns were made using the following common steps: opening the fibers and mixing,

carding,

Hydroentanglement,

Removing water,

Drying in the through-air dryer and winding

The line speed was in the range of 55-100 m / min, and cylinders with a total of 4 water injectors were used on the hydroentanglement unit. The set water pressure values were in the range of 30-80 bar. The nozzle bars in the injectors were conventional nozzle bars that can be used for any conventional hydroentangled product in this weight range.

The nonwoven fabric may also be formed by other nonwoven processes such as dry lay, wet lay or air lay processes. • e t · • M i ft • • e • • ··· *! n • • «························································· PL0534

The nonwoven may be consolidated by any conventional nonwoven bonding process, including hydroentanglement, needling or chemical strengthening.

The fleece can have a basis weight of 10 to 2000 g / m2. For wipes, a nonwoven having a basis weight of 25 to 200 g / m 2 is preferred. For technical applications such as oil-absorbing mats, basis weights of up to 2000 g / m2 are suitable.

The gravimetric absorption time (GAT) is measured according to WSP 242.3 [or ERT 442.2 similar to IST 242 (02)]. This shows how much water is absorbed into a fleece in a given time.

Table 1 shows the water absorbency (GATS) values of nonwovens prepared by the process described with various fiber blends of hydrophobic lyocell fibers and conventional lyocell fibers. The lyocell fibers are lyocell fibers made by Lenzing AG under the Tencel brand.

Lower levels of admixture (5-10% hydrophobic Tencel) result in an increase in absorbency of 5%, higher levels (20-30%) result in 15% higher absorbency, while amounts greater than 40% hydrophobic fibers result in water repellency and low absorbency Absorbing capacity lead.

Table 2 shows similar results for mixtures of hydrophilic Tencel and viscose.

Table 1

Pattern Blend GATS blends of hydrophilic Tencel with Tencel lg H20 / g hydroentangled web] 1 100% Tencel 1.7 / 38 8.6 2 5% Tencel hydrophobic 1.7 / 38 -95% Tencel 1.7 / 38 8.9 3 30 % Tencel hydrophobic 1.7 / 38 -70% Tencel 1.7 / 38 9.8 4 50% Tencel hydrophobic 1.7 / 38 -50% Tencel 1.7 / 38 0.8 5 70% Tencel hydrophobic 1.7 / 38 -30% Tencel 1.7 / 38 1.2 6 100% Tencel hydrophobic 1.7 / 38 1.0 PL0534 · * 9999 - R · * 99 9 99 W # · · · · 9 9 9 9 9 · · · · · * 999 * · * · ···· · · · 9 * · 99 99 99

Table 2:

Blend GATS Mixtures of hydrophobic lyocell and viscose [g H20 / g hydroentangled nonwoven] 7 100% Viscose 1.7 / 38 7 · 8 8 30% Tencel hydrophobic 1.7 / 38 -70% Viscose 1.7 / 40 8.3 g 50% Tencel hydrophobic 1.7 / 38 -50% Viscose 1.7 / 40 2.9 10 70% Tencel hydrophobic 1.7 / 38 -30% Viscose 1.7 / 40 0.7

Another object of the invention is to provide a fully biodegradable nonwoven which has a surface tension that has been optimized to suit different liquids. This can be used to maximize absorbency or optimization by optimizing fluid intake or delivery

To improve the cleaning power of a wipe for a specific purpose.

A method for determining the surface tension of a surface in the laboratory is set out in BS ISO 8296: 2003: A set of different liquids (for example water, methanol, ethylene glycol monoethyl ether or formamide) is used to increase the surface tension, as shown in Table 3 determine. These tests are used, for example, in plastic film making to verify that the surface is printable. Test inks from ARCOTest GmbH in Germany were also used.

Table 3:

Liquid surface tension fmN / m] 80 ml MeOH + 20 ml H »0 27.3 36.5 ml ethylene glycol monoethyl ether (EGMEE) + 63.5 ml formamide 40 · 100 ml ethylene glycol 48 9.3 ml EGMEE + 90.7 ml formamide 50 6.3 ml EGMEE + 93.7 ml Formamide 52 100 ml Formamide 58 50 ml Formamide + 50 ml Water 63 100 ml H20 (purified for use with HPLC) 73 Test Ink from ARCO 76 Test Ink from ARCO 84 Test Ink from ARCO 90

Claims (5)

PLQ534 -η ι · «·. ·······························································································. · · · · · ≫ 1) nonwoven fabric comprising a blend of two types of fibers, wherein the first type of fiber is a ceulosic fiber and the second type of fiber is a biodegradable hydrophobic cephulosic fiber, characterized in that the absorbency for a liquid compared to a nonwoven having the highest absorbency for these Liquid comprising only one of the fiber types is at least 5% higher. 2) Nonwoven fabric according to claim 1, characterized in that the mixture 5 to 40 wt .-% 10 fibers of the second fiber type and 95 to 60 wt .-% fibers of the first fiber type, preferably 5 to 30 wt .-% fibers of the second fiber type and 95 to 70% by weight of fibers of the first fiber type, 100% in total, and the liquid has a surface tension greater than or equal to 50 mN / m. 15 20 The nonwoven fabric according to claim 1, characterized in that the mixture comprises 40 to 95% by weight of fibers of the second fiber type and 60 to 5% by weight of fibers of the first fiber type, preferably 30 to 95% by weight of fibers of the second fiber type and 70 to 5 wt .-% fibers of the first fiber type, in total 100%, and the liquid has a surface tension greater than or equal to 50 mN / m. 4) The nonwoven according to claim 1 to 3, characterized in that the first and the second fiber type is a celulosic man-made fiber selected from the group consisting of viscose fibers, lyocell fibers or modal fibers. 25 5) fleece according to claim 1 to 4, characterized in that the first and the second fiber type is a celulosic natural fiber, such as cotton. Nonwoven fabric according to claim 1 to 5, characterized in that the hydrophobic fiber is a hydrophobing agent in an amount of 0.01 to 1 wt .-%, preferably from 0.05 to 0.2 wt .-%, based on of cellulose. 7) Nonwoven according to claim 6, characterized in that the hydrophobizing agent is an alkyl ketene dimer. 8) Nonwoven fabric according to one of the preceding claims, characterized in that the nonwoven fabric is formed by means of a typical nonwoven process, including dry-laid, wet-laid or air-laying processes. PL0534 -12 »··· * ···· • · · · · · + +« f ···· ♦ · ·. 9) Nonwoven according to one of the preceding claims, characterized in that the nonwoven is solidified by means of a typical nonwoven method comprising hydroentanglement, needling or chemical strengthening. 5 10) Nonwoven according to one of the preceding claims, characterized in that the nonwoven fabric has a basis weight of 10 to 2000 g / cm2. 11) nonwoven product, comprising a nonwoven fabric according to claim 1 to claim 10 and a 10 liquid, characterized in that the surface tension of the nonwoven with a deviation of less than +/- 5% in the range of the surface tension of the liquid. 12. Nonwoven product according to claim 11, characterized in that the liquid is a lotion. 13) A nonwoven product comprising a nonwoven according to claim 11 to claim 12, characterized in that the deviation of the uniformity of the distribution of the aqueous solution when tested according to the described " liquid retention and release test " better than +/- 15%. 14) Use of a nonwoven fabric according to claim 1 to claim 13 in hygiene applications such as toilet tissues, facial tissues, facial tissues, Babytüchem, Sanitärtüchern, household towels, industrial cloths and in packaging material for food. 25 15) Use of a nonwoven fabric according to claim 1 to claim 13 in technical applications such as materials for receiving oil.