WO2015154110A1

WO2015154110A1 - Colored blends of fibers and their use

Info

Publication number: WO2015154110A1
Application number: PCT/AT2015/000054
Authority: WO
Inventors: Ksenija Varga; Elisabeth STANGER
Original assignee: Lenzing AG; Chemiefaser Lenzing AG
Current assignee: Lenzing AG
Priority date: 2014-04-07
Filing date: 2015-04-03
Publication date: 2015-10-15
Anticipated expiration: 2016-10-07
Also published as: AT515736A1; AT515736B1

Abstract

This invention is about functional blend of lyocell and spun-dyed viscose fibers with FDA and INCI incorporated pigments. In particular very homogenous non-woven fiber blends can be produced. The spun-dyed viscose fibers contain FDA and INCI approved pigments like Vat Blue 1, Pigment Red 170, Red 121, Yellow 83, Violet 23, Yellow 1, Yellow 110, Yellow 3, Yellow 74, Red 146, Red 2, Blue 15:3, Blue 15, Green 7, Black 7, Red 254. These fibers fulfill the requirements of the European Pharmacopeia according to standard 01/2008:0034 (version 6.0). The lyocell fibers can contain for example active agents like ZnO or Silver to provide antibacterial function. The fiber blends according to the invention can be used for wipes (intimate, facial, baby, cleaning), facial masks, for top sheets and ADL parts of the female hygiene products, baby diapers and incontinence products. These fiber blends enable excellent lotion management performance.

Description

Colored blends of fibers and their use

This invention relates to functional blends of lyocell and spun-dyed viscose fibers with FDA- and INCI-listed incorporated pigments and to the use of such fiber blends. In particular very homogenous non-woven fiber blends can be produced.

The spun-dyed viscose fibers contain FDA- and INCI-listed pigments like Vat Blue 1 , Pigment Red 170, Red 121 , Yellow 83, Violet 23, Yellow 1 , Yellow 110, Yellow 3, Yellow 74, Red 146, Red 2, Blue 15:3, Blue 15, Green 7, Black 7, Red 254. These fibers fulfill the requirements of the European

Pharmacopeia according to standard 01/2008:0034 (version 6.0). The lyocell fibers can contain for example active agents like ZnO or Silver to provide antibacterial function.

The fiber blends according to the invention can be used for wipes (intimate, facial, baby, cleaning), facial masks, for top sheets and ADL parts of the female hygiene products, baby diapers and incontinence products. These fiber blends enable excellent lotion management performance.

Prior Art

Existing colourful nonwoven wet wipes are often composed of blends of spundyed viscose and colorless synthetic fibers, wherein the synthetic fibers mostly are polyester, polypropylene and/or synthetic bicomponent fibers. The cellulosic component provides for the good absorbency of liquid, while the polyester component provides for the necessary wipe tenacity.

Problem

With regard to the purpose of such colourful wet wipes the existing products show some significant disadvantages: The negative feature of such blends is that the applied pigments are not in accordance with FDA and INCI regulations and therefore in general, they could not be used for hygiene purpose; especially not for hygiene wet wipes, baby wipes, sanitary products and facial masks.

Another significant disadvantage is that the blending of the viscose and synthetic fibers does not result in an ideal homogeneous mixture of both fiber types. This effect would not be relevant for blends where both the viscose and synthetic fibers are of the same color or colorless, but if only one of these fiber components is colored, then the inhomogeneities are obvious. This effect is not appreciated by customers.

In view of these disadvantages the object of the present invention was to provide blends of spundyed cellulosic fibers and colorless fibers suitable for the manufacture of nonwoven wet wipes which show a sufficiently high wipe tenacity as well as a homogenic color appearance.

Another object of the present invention was to provide blends of spundyed cellulosic fibers and colorless fibers which are suitable for the use in hygiene articles, such as in feminine hygiene applications, hygiene wet wipes, baby wipes, sanitary products and facial masks, all of which require the accordance with FDA and INCI regulations.

Description of the invention

The present invention includes giving function to the colourful wet wipe made of Lyocell and spun-dyed viscose. For the purposes of the present invention the term "spun-dyed viscose" shall include corresponding fibers spun according to the Modal process. It shall also include corresponding fibers spun according to a modified Modal process using H₂O₂ as bleaching agent.

It is an object of the present invention to provide a fiber blend for the use in nonwoven products for hygiene applications, characterized in that it contains spun dyed viscose fibers and colorless lyocell fibers. In the fiber blend according to the invention the weight ratio of spun dyed viscose fibers and lyocell fibers is between 10:90 and 90:10, preferably between 30:70 and 70:30 and most preferably between 40:60 and 60:40.

In a particularly preferred embodiment of the fiber blend according to the invention the pigments used for the spin dying are fulfilling the requirements of the applicable FDA and I NCI specifications.

Various viscose fibers can be blended in wipes in various blending ratios, starting from 10 to 90% in the two- three- or four component wipe. For good performance of the product, the most suitable blend ratio is between 30-50 % spundyed viscose and 50-70 % lyocell component.

In the blend, various lyocell fibers can be used, with fineness from 1 dtex to 15 dtex. The cut length of the fibers can vary from 6 mm to 50 mm. For colorful wipes preferred fiber characteristics are from 1.3 to 1.7 dtex fineness and 38 to 50 fiber length.

For baby, cosmetic pads and household wipes the most suitable fineness of the lyocell fibers is between 1.3 and 1.7 dtex and fiber cut length between 30 and 50 mm. For hygiene wet wipe and flushable wipe, the most suitable is fiber fineness of the Lyocell fibers between 1.3 and 1.7 dtex and fibre cut between 6-10 mm. For all applications the preferred characteristics of spun- dyed viscose fibers are from 1.3 to 1.7 dtex fiber fineness and a fiber length in the same range than the fiber length of the Lyocell fiber component.

The colourful wipe blends according to the invention are suitable for baby wipes, facial cleaning wipes, intimate wipes, household wipes, sanitary products and facial mask.

The colourful wipe blend according to the invention can be in the form of fiber bales (which is the usual form for the transport of staple fibers) wherein a bale contains both fiber components already blended before compressing. In an alternative embodiment of the invention the blend may be prepared from bales which contain only one fiber component during the so-called "opening" or before or during carding of the opened fibers of the different components.

It is a further object of the present invention to provide a use of the fiber blends as described herein for the manufacture of nonwoven products for hygiene applications as well as for cosmetic wipe applications. In particular these nonwoven products for hygiene applications are - among others - wet wipes, hygiene wet wipes, flushable wipes, facial masks, top sheets, baby diapers, female pads, pantyliners, and incontinence products. For all these applications the nonwoven product according to the invention contains a lotion according to the intended application.

The nonwoven fabrics can be formed by the methods known in the art, in particular by needlepunching and spunlacing, i.e. by involving a

needlepunching and/or spunlacing step. According to the invention no thermobonding step is needed to produce the nonwoven fabric.

Advantages of the fiber blends according to the invention are in particular:

• By using the fiber blends according to the invention, the superior

processability of the blended fibers on the non-woven facility enables running with full capacity because the cellulosic fibers stick together much better than blends of cellulosic with synthetic fibers. Therefore by using lyocell fiber instead of the synthetic fiber in the fiber blend, the tenacity of the resulting nonwoven is significantly higher which result in a better processability for example in the spun lace machines.

• In colorful wipes made of fiber blends according to the invention the colored fiber component is much more evenly distributed within the colorless fiber matrix.

• In the spun-dyed viscose the pigments are completely and

homogenously incorporated in the fiber structure; therefore the production facilities for the nonwovens are not contaminated by pigment dust. • top-sheets made using the fiber blends according to the invention enable better comfort for females and baby skin and therefore support a healthier skin.

• Colorful face masks can be produced by using the fiber blends

according to the invention. Such face masks support the regeneration of the skin cells.

Additional features of the fiber blends according to the invention are:

• Pigments are fully incorporated in the fiber structure and do not cause any negative influence on the human skin.

• By using lyocell, the absorption of the lotion is improved and the

release of the active substances can be regulated precisely.

• While it is not possible to spread lotion homogenously on the non- woven surface of polyester wipes due to their hydrophobic character and therefore the release of active substances cannot be precisely controlled there, such release of active substances can be much more precisely controlled in nonwovens made using the fiber blends according to the invention.

• Lyocell / spun-dyed viscose blends are sustainable, hygiene products which are biodegradable. The use of these fiber blends enables significant savings in the consumer chain concerning water and energy use. Also emission of C0₂ is much lower if the fiber blends according to the invention are used.

To give a special function to the colourful wipes, the lyocell fibers can be treated with a special agent, like for example anti-bacterial agents (Silver, ZnO), essential oils, super absorbing (CMC, Poly-DADMAC, PEG).

To achieve a peeling effect of the fibers, CaC0₃ can be incorporated into the fibers. A grinded or precipitated CaC0₃ can be used for functional wipe.

CaC0₃ can be incorporated into the lyocell or into the spun-dyed Viscose. The functional additives can be incorporated into the fibers during the spinning process, or the fibers can be treated afterwards in the after-treatment step. The functional additives can also be incorporated into Viscose material.

The fibers in the blend according to the invention can contain optical brighteners like triazine-stilbenes, coumarins, imidazolines, diazoles, triazoles, benzoxazolines, biphenyl-stilbenes.

The pigments used for the spindyeing are in agreement with FDA and INCI specifications. Allowed pigments are: Vat Blue 1 , Pigment Red 170, Red 121 , Yellow 83, Violet 23, Yellow 1 , Yellow 110, Yellow 3, Yellow 74, Red 146, Red 2, Blue 15:3, Blue 15, Green 7, Black 7, Red 254. These pigments are medically approved for the sanitary clean products.

Dispersants for the dyes used for spindyeing the fibers according to the invention have to also be in agreement with FDA and INCI list. Allowed dispersants are: Dimethylolpropionic acid, Phosphorilated tall oil fatty acids, Propanoic Acid, Siloxanes and Silicones (Cethylmethyl, dimethyl, methyl 11- methoxy-11-oxoundecyl), Trimethylolethane, Trimethylolpropane. The fiber soft-finish as well has to fulfil the requirements listed in FDA and INCI list.

The fiber components used in the invention (lyocell, spun-dyed viscose and spun-dyed modal fibers) can be produced according to the nonwovens regulation for the clean production. Such fibers are commercially available from Lenzing AG, Lenzing, Austria.

The invention will now be illustrated by examples. These examples are not limiting the scope of the invention in any way.

Examples

In all trials the lyocell fiber was TENCEL^® of Lenzing AG, Lenzing, Austria and the spun-dyed viscose fiber was also obtained from Lenzing AG, Lenzing, Austria. In order to prove the advantages of the blend of lyocell and spun- dyed viscose according to the invention, two methods were used: 1. Forming of fiber foils in the wet state.

2. Forming of fleeces.

Method 1 :

Commercially availableTENCEL®-fibers and spun-dyed viscose fibers containing incorporated FDA-listed pigments were blended on a carding machine. The thus carded blends were cut down to 5 mm fiber length. The cut fibers were placed in a laboratory-scale film making device, swirled for 3 seconds and sucked afterwards. The wet films were dried for 10 min.

Fig. 1 to 4 show scans of the blended fibers, wherein Fig. 1 and 3 show the homogenous blend of 70% TENCEL^® and 30% Viscose Spun-Dyed; and Fig. 2 and 4 show the very irregular blends of 70% Polyester and 30% Viscose Spun-Dyed.

In Fig. 1 and Fig. 3, the differences in the fiber distribution are visualized: The two cellulosic components according to the invention can be blended very homogenously which is important for the usage of the functional nonwovens. If the fibers are blended very homogenously, the absorption and desorption of lotions is only possible within the homogenous nonwovens.

Method 2:

Advantages of lyocell in a functional wet wipe - a basic characteristic in comparison to Polyester in wet wipes was characterized by two parameters.

Fig. 5 shows the water retention values of 100% lyocell in comparison to 100% polyester. This measure indicates a capability of the fiber to absorb a regular lotion typically used on wet wipes as a basis function of the wipes. Lyocell absorbs 60% lotion while polyester absorbs only 3% lotion.

Fig. 6 shows the rate of spread, 100% lyocell vs. 100% polyester. The rate of spread is relevant for spreading of liquid in sanitary products. This graph proves that functional nonwoven containing lyocell can spread more than 2000 mm² of lotion while polyester spreads only 500 mm² lotion according to a standard test method.

Table 1 shows the results of the fiber testing according to European

Pharmacopeia Regulation (01/2008:0034 - improved version 6.0). The newly developed fibers fulfil the regulation requirements (see ΈΡ limits") given by this Regulation.

Additionally it was proven that the incorporated pigments were not dissolved by the used standard test lotions which are the industry standards for cosmetic and baby wipes.

Tab. 1 : Results of the European Pharmacopeia Regulations for spun-dyed Viscose with FDA-listed incorporated pigments

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Claims

1. Fiber blend for the use in nonwoven products for hygiene applications, characterized in that it contains spun dyed viscose fibers and colorless lyocell fibers.

2. Fiber blend according to claim 1 , wherein the weight ratio of spun dyed viscose fibers and lyocell fibers is between 10:90 and 90:10, preferably between 30:70 and 70:30 and most preferably between 40:60 and 60:40.

3. Fiber blend according to claim 1 , wherein the pigments used for the spin dying are fulfilling the requirements of the FDA and INCI specifications.

4. Fiber blend according to claim 1 , wherein the spundyed viscose fibers are made according to a regular viscose process or according to a modified viscose process, generally also known as modal process.

5. Use of the fiber blends of claim 1 for the manufacture of nonwoven products for hygiene applications or for cosmetic wipe applications.

6. Use according to claim 5, wherein the manufacture of the nonwoven products involves a needlepunching or spunlacing step.

7. Use according to claim 5 wherein the nonwoven products for hygiene applications are wet wipes, hygiene wet wipes, flushable wipes, facial masks, top sheets, baby diapers, female pads, pantyliners, and incontinence products.

8. Use according to claim 7, wherein the nonwoven product contains a lotion according to the intended application.