EP3115502B1 - Hydrophobic wash resistant celloluse fibres and method for mkaing cellulose fibres wash resistant and hydrophobic - Google Patents

Description

The present invention relates to a process for the wash-resistant hydrophobing or to produce a wash-resistant hydrophobing of cellulose fibers and to dyeable, wash-resistant, hydrophobicized cellulose fibers.

Cellulose fibers, in particular so-called man-made cellulose fibers, such as e.g. Viscose fibers, modal fibers, cupro and lyocell fibers, consist of the hydrophilic polymer cellulose. This native polymer has a high number of hydroxyl groups in its polymer chain, which form a correspondingly high number of polar centers. Due to these polar centers, the polymer chains have a low contact angle with respect to water, so that the cellulose fibers are very readily wettable with water. This property is preferably used in many applications of cellulose fibers, because products made of such fibers have high water absorbency and thus a high water absorption capacity. This is additionally supported by the porosity of the fiber material, which has high water accessibility, since liquid water and also water vapor can very easily penetrate into an untreated cellulose fiber.

Due to the ability to absorb and bind water vapor by sorption, man-made cellulose fibers also have a high moisture absorption capacity, which is sometimes desirable for a comfortable fit of clothing made of these fibers. Usual moisture storage capacities of cellulose fibers are between 10% -Gew. and 15% weight. of dry fiber weight. In contrast, the moisture storage capacity is at a hydrophobic Synthetic fiber, eg a fiber made of polypropylene or polyester, under normal climatic conditions at about 1% wt. of fiber weight. In the presence of water or sweat, a cellulose fiber by swelling and filling of the pores very quickly absorb more liquid, with a water storage after centrifuging the excess and therefore removable water in the range between 60% -Gew. and 100% -gew. the weight of the material lies.

However, the high absorption capacity for water also requires that such textiles become heavy, which is often perceived on skin contact as an unpleasant feeling of wetness and cold. In addition, the slow drying of wet textiles made of cellulose fibers also leads to a reduced wearing comfort. For applications with high perspiration, e.g. in sports textiles, therefore, hydrophobic, non-swelling fiber materials are often used, e.g. Polyester, polyamide or polypropylene. These do not absorb the sweat inside, but pass it on quickly, for example in the case of multi-layer sports textiles to an adjacent absorbent fiber layer. If the absorbent fiber layer, e.g. from cellulose fibers, in a skin-distant textile layer, so liquid sweat is absorbed there, while the synthetic non-polar fibers in a close-knit textile layer convey a pleasant feel.

Various methods are known from the prior art for hydrophobicizing cellulose fibers. Thus, on the one hand, by chemical modification of the polymeric chain, the hydrophilic cellulose polymer can be converted into a hydrophobic polymer. This modification can take place, for example, by acetylation, which then leads to the known products cellulose diacetate or triacetate, which are synthetic with respect to water and moisture storage capacity Show chemical fibers similar behavior. In addition to the considerable processing required to modify the polymer, other positive properties of cellulose products are largely lost.

Furthermore, a hydrophobing can take place by incorporation of hydrophobic substances during fiber production or by a post-treatment with hydrophobing agent immediately after fiber production. Typical methods for this are in AT 512 143 A1 and AT 512 144 A1 discloses in which after the fiber production, a hydrophobization treatment of the cellulose fiber takes place. However, the incorporation and modification of the cellulose sometimes causes a disturbance of the fiber structure, which is usually accompanied by considerable loss of strength of the fibers. Therefore, such hydrophobing methods are usually dispensed with.

The hydrophobing of textile products such as fibers, yarns and fabrics can also be carried out in the form of a so-called finishing treatment, which is carried out as a step in textile finishing as part of the equipment. For example, in US 2 411 860 A used a hydrocarbon-based reactive chemical system. Alternatively, treatment with long chain fluorocarbon chemicals is possible. Siloxane-based chemicals can also be used to hydrophobize cellulose fibers and cellulosic textiles.

As a consequence of the hydrophobization treatment of the cellulose, in addition to water, the absorption capacity for other chemicals and dyes is also reduced, which is referred to in the specialist literature by the term reservation. Thus, for example, dyeing treatments of cellulosic fibers occur typically before a hydrophobing, regardless of the type of hydrophobing method, since otherwise experienced experience the following problems. For example, the reduced dye receptivity leads to a distinctly lighter hue and to a poorer dye fixation. In addition, there is a very high probability of uneven colorations, so that streaks and stains are expected in the dyed material. Also, the chemicals used in the dyeing process often lead to a subsequent reduction in the effectiveness of the hydrophobic treatment and thus to a reduction of the originally desired water-repellent effect. Consequently, in the processes known from the prior art, the hydrophobing treatment usually represents the last processing step, since subsequent wet-chemical further processing is only possible with difficulty.

Hydrophobing treatments in early processing stages, such as at the stage of fibers and yarns, are only common if subsequently no further wet treatments take place. From the point of view of the hydrophobing effect, however, treatment at the fiber level would be preferable since it allows the treatment chemicals to be brought into the interior of the subsequent yarn, which is no longer possible even when processed at the production stage of yarns. Because of the strong swelling of the cellulose fibers, the penetration of the treatment chemicals into the interior of the yarn becomes impossible, so that in the case of a treatment of yarns - and to an even greater extent of fabrics - the functional chemicals are deposited primarily only on the surface of the textile structure. However, because of the above-mentioned reasons of the color reservation and the loss of hydrophobic properties by the dyeing steps, hydrophobing treatments have occurred Fiber level not yet implemented for industrial mass production.

The DE 10 2013 209 170 A1 discloses a chemical composition for producing a water-repellent, wash-permanent hydrophobic treatment of textile surfaces, which consists of a combination of silicone polymers and wax and / or fatty acid esters, and preferably additionally aminoplasts. For applying these water repellents exhaust or forced applications are proposed.

From the US 2 750 305 A For example, a method of hydrophobizing textile materials using polysiloxanes is known. The application of the hydrophobizing agent can be carried out by a discontinuous exhaust process. The textile material used is cellulose acetate or viscose.

The document " Modern Stain Protection Equipment of Textiles "(Lämmermann, D., Melliand Textile Reports, 74 (9), 1993, XP000394776 ) mentions paraffin, modified fatty acids and fluorocarbons as auxiliaries which are supposed to make possible the water-repellent finishing of textile materials. For application of the hydrophobing agent, various application techniques are described, in particular exhaust and padding processes.

From the US 2007/0093162 A1 For example, substances are known which have a layer of hydrophobic material on the body-facing side and a layer of hydrophilic material on the side facing away from the body. The hydrophobic material can be prepared by hydrophobizing yarns of hydrophilic materials such as cellulose. The document also discloses a method of hydrophobizing the yarns. Further is discloses that, instead of the yarns, the fibers can already be rendered hydrophobic in order subsequently to produce yarns thereon.

The object of the present invention is therefore to provide an improved process for producing a wash-resistant hydrophobization of cellulose at the production stage of fibers, wherein the cellulose fibers on the one hand after hydrophobing no or only slight color reservation effects and on the other hand after dyeing still sufficiently large water-repellent properties respectively.

This object is achieved by the method according to claim 1 and the cellulose fibers according to claim 13. Advantageous embodiments of the invention are the subject of the dependent claims.

1. a. Aufbringen eines Hydrophobierungsmittels auf die Cellulosefasern auf der Fertigungsstufe von Fasern vor dem Färben in einem diskontinuierlichen Ausziehprozess durch Eintauchen der Cellulosefasern in ein Ausziehbad aus einer wässrigen Emulsion, die das Hydrophobierungsmittel enthält, wobei das Hydrophobierungsmittel als hydrophobierend wirkende Aktivsubstanz wenigstens einen der folgenden Stoffe enthält: wenigstens ein Derivat der langkettigen Kohlenwasserstoffe, wenigstens ein Fettalkoholderivat, wenigstens ein Fettaminderivat, wenigstens ein Derivat einer Fettsäure, dadurch gekennzeichnet, dass bei wenigstens 90 % der jeweils davon vorhandenen Moleküle in der hydrophobierend wirkenden Aktivsubstanz die Anzahl der Kohlenstoffatome in der hydrophoben Kette wenigstens 12 Kohlenstoffatome beträgt;
2. b. Ablassen des Ausziehbades oder Herausnehmen der Cellulosefasern aus dem Ausziehbad;
3. c. Trocknen der Cellulosefasern.

The process according to the invention for producing a wash-resistant hydrophobization or for washing-resistant hydrophobing of cellulose fibers or for producing wash-resistant hydrophobicized cellulose fibers is characterized by the following steps:

1. a. Applying a hydrophobing agent to the cellulose fibers at the stage of manufacture of fibers before dyeing in a batch process by immersing the cellulose fibers in an aqueous emulsion containing the hydrophobizing agent, wherein the hydrophobing agent contains as hydrophobizing active substance at least one of the following substances: at least a derivative of long-chain hydrocarbons, at least one fatty alcohol derivative, at least one fatty amine derivative, at least one derivative of a fatty acid, characterized in that at least 90% of the respective molecules present in the hydrophobizing active substance, the number of carbon atoms in the hydrophobic chain is at least 12 carbon atoms;
2. b. Draining the Ausziehbades or removing the cellulose fibers from the Ausziehbad;
3. c. Drying the cellulose fibers.

These known from the prior art for the hydrophobic finishing of textiles chemicals are not water soluble and are applied in the form of emulsions. Because of the associated unexpanded affinity for cellulose these chemicals have been applied to ensure a certain order amount so far only by the so-called continuous process (continuous processing) by dipping and squeezing and then drying and thermal fixing. This technique is also usually implemented only for fabrics and yarns. Continuous fiber-level treatment is not common.

In accordance with the invention, it has now been recognized that the implementation of continuous equipment in a batch exhaustion process, using water repellents which previously appeared to be suitable only for continuous processing, unexpectedly resulted in the production of a wash resistant hydrophobization of cellulose at the manufacturing stage leads the fibers, wherein the fiber core of the cellulose fiber treated according to the invention remains largely unchanged.

In addition, it has been recognized in accordance with the invention that the fibers thus treated have a sufficiently good dyeability without adversely affecting the water-repellent properties produced by the dyeing. Thus, the cellulose fibers treated according to the invention can be dyed without appreciable dye-reserving effects, in particular by customary processes of reactive dye-dyeing. The differences in the dye receptivity can be evaluated by comparative experiments with patterns of hydrophilic fibers and are at a maximum of 20% in the color depth, which is unexpectedly low for a hydrophobically finished product.

According to a preferred embodiment of the invention, a thermal fixing of the hydrophobizing agent to the cellulose fibers is additionally carried out after drying. Both drying and fixing by hot air are preferably carried out. In a preferred embodiment of the invention, the drying of the cellulose fibers is carried out at a temperature of over 100 ° C, in particular at a temperature between 105 ° C and 140 ° C, preferably between 110 ° C and 120 ° C.

In contrast, according to a further advantageous embodiment of the invention, the temperature during thermal fixing between 110 ° C and 190 ° C, preferably between 130 ° C and 170 ° C, more preferably between 140 ° C and 160 ° C.

Depending on the starting material and the hydrophobizing agents used, the time for the thermal fixing may be between 30 seconds and 4 hours. In a preferred embodiment, the time for the thermal fixation between 5 minutes and 2 hours.

According to a further advantageous embodiment of the invention, the cellulose fibers are formed as flock fibers. The applied discontinuous extraction process by immersing the cellulose fibers in an emulsion bath is advantageously suitable as a batch process. Therefore, in a further embodiment of the invention, the cellulose fibers, in particular bundled as fiber bales, can be fed to the exhaust bath.

In order to achieve the best possible and uniform deposition of the hydrophobizing agent on the surface of the cellulose fibers, the temperature of the exhaust bath in a further advantageous embodiment of the invention between 20 ° C to 110 ° C, preferably from 30 ° C to 80 ° C, particularly preferred between 40 ° C and 60 ° C. The temperature of the exhaust bath may sometimes depend on the starting material and / or the hydrophobizing agents used.

Also depending on the starting material and / or the hydrophobizing agents used in a further advantageous embodiment of the invention, the proportion of the hydrophobizing active substance between 0.1 wt .-% and 10 wt .-%, preferably between 0.2 wt .-%. and 8% by weight, more preferably between 0.3% by weight. and 4% by weight, the total mass of the cellulose fibers to be treated.

The so-called liquor ratio, ie the ratio of the volume of the aqueous emulsion to the total mass of the cellulose fibers to be treated, is again dependent in a further advantageous embodiment of the invention from the starting material and the hydrophobizing agents used between 0.4 l / kg and 40 l / kg, preferably 1 l / kg to 20 l / kg, more preferably 5 l / kg to 15 l / kg.

The residence time in the exhaust bath also influences the result of the surface finishing of the fibers. In a further advantageous embodiment of the invention, this is between 0.5 min and 180 min, preferably 20 min and 120 min, more preferably between 60 min and 120 min.

In addition, it may be advantageous that the exhaust bath is circulated, pumped and / or stirred during the application of the hydrophobing agent to the cellulose fibers. It is conceivable, for example, that the cellulose fibers are introduced as packing bales in a container through which the emulsion is pumped through and thereby flows through the fiber bale. Also conceivable are agitators for circulating or stirring the Ausziehbades. Particularly preferably, the circulating, pumping and / or stirring is shear-reduced so that the sometimes very shear-sensitive emulsion is not destroyed.

According to an advantageous embodiment it can be provided that in the case of the at least one derivative of the long-chain hydrocarbons and / or the at least one fatty acid derivative and / or the at least one fatty alcohol derivative and / or the at least one Fatty amine derivative in at least 90% of the respective molecules present in the hydrophobic active substance, the number of carbon atoms in the hydrophobic chain at least 16, preferably at least 20, most preferably at least 24 carbon atoms.

When using hydrophobing agents which contain derivatives of the long-chain hydrocarbon groups, functional groups in the at least one derivative of the long-chain hydrocarbons may be, for example, alcohols, amines or carboxylic acids, carboxylic esters or carboxamides. The hydrocarbon chains may have a linear or branched structure, wherein in a preferred embodiment, the functional group of the derivative is positioned at one end of the linear carbon chain. In a particularly preferred embodiment, a branch of the carbon chain is located on the side opposite the functional group of the derivative side of the carbon chain, which may be present as branches, for example, structures analogous to the tert-butyl, iso-propyl or sec-pentyl group , Especially with longer carbon chains, with for example over 18 carbon atoms, the functional group of the derivative may also be positioned within the carbon chain and e.g. by altering an originally present double bond of a natural fat or oil. When using fatty derivatives from natural raw materials, the hydrocarbon chain may also contain unsaturated bonds, with palmitoleyl alcohol, oleyl alcohol or γ-linolenyl alcohol being conceivable as examples.

As cellulose fibers are in particular so-called man-made Cellulose fibers, in particular viscose fibers, modal fibers and / or lyocell fibers.

The hydrophobicized according to the inventive method cellulose fibers are characterized according to a further aspect of the invention in that they have after hydrophobing a dye receptivity of an aqueous medium which is reduced by not more than 20% compared to the dye receptivity of the cellulose fibers before hydrophobing. This value can be determined, for example, by measurements of the color difference "Delta E" and the so-called Kubelka-Munk K / S values (K = absorption component and S = abstract scattering component) between patterns of hydrophobic fibers and patterns of hydrophilic fibers, each according to the same procedure were dyed, to be checked.

Furthermore, according to a preferred embodiment of the invention, the complete surface of the so hydrophobized cellulose fibers in comparison to cellulose fibers in products that were not hydrophobic at the manufacturing stage of fibers, but at the manufacturing stage of yarns, fabrics or knitted fabrics, a uniform coating or annealing the hydrophobizing agent. By appropriate analytical techniques, e.g. Electron microscopy, a direct distinction of carried out at the different stages of production hydrophobing can be done.

Since the hydrophobing treatment according to the present invention mainly relates to the fiber surface, the hydrophobized cellulose fibers and textile products derived therefrom are characterized, inter alia, by the fact that the interior of each cellulose fiber is substantially free of Is hydrophobicizing agent. Although the treated fibers are still wettable by water, the water uptake into the fiber interior is greatly delayed compared to untreated fibers. Thus, the hydrophobized fibers according to the invention show similar transport properties as hydrophobic synthetic fibers or wool. In contrast, however, they substantially preserve the beneficial climate buffering and wet absorbency of untreated cellulosic fibers.

The invention further relates to a textile product, in particular a woven fabric, a knitted fabric, a so-called nonwoven, a yarn or a twisted yarn, which are produced from at least one or more cellulose fibers according to the invention. For example, non-wovens or nonwovens of such hydrophobized cellulosic fibers can be used for personal care products such as liners and diapers.

Fig. 1

als Blockdiagramm die Schritte einer beispielhaften Ausführungsform des erfindungsgemässen Verfahrens illustriert.

Other objects, advantages and applications of the present invention will become apparent from the accompanying figure, wherein

Fig. 1

as a block diagram illustrates the steps of an exemplary embodiment of the inventive method.

Furthermore, a noninventive embodiment (reference example) of the process is shown in which micromodal is used as cellulosic fiber material. The raw material is in flake form as fiber bales an extraction bath of an aqueous emulsion containing as a hydrophobing agent, a commercial C6 fluorocarbon product, ie a hydrophobing agent with Fluorocarbons as a hydrophobizing active substance contains, supplied and treated by exhaustion for 2 hours at a Ausziehbadtemperatur of 60 ° C (100). The application rate of the hydrophobizing active substance is 5% by weight of the mass of the product. The liquor ratio is 1: 8, ie the ratio of the volume of the aqueous emulsion to the total mass of the cellulose fibers to be treated is 8 l / kg.

After 2 hours, the exhaust bath is drained (200).

Thereafter, the cellulose fibers are dried at 120 ° C (300) and subjected to thermal fixation (400) for 5 minutes by means of hot air at 140 ° C.

From the thus treated fiber materials, a yarn with the metric number 100 (100 m / g) is produced by the conventional method of cotton spinning, from which by circular knitting an interlock material is produced. After washing and dyeing the knit fabric with reactive dye, a red functional knitted fabric (material A) is obtained. For comparison, the same material is made from untreated, hydrophilic fibers (material B). The two textiles have the following properties: Material A Material B Water retention (spin value) 31% 38% Moisture absorption (65% relative humidity, 20 ° C) 8.3% 9.3% Water absorption in the water distribution test, washed 5 times 0.0152 g 0.0489 g Water absorption in the water distribution test, washed 15x 0.0222 g 0.0555 g

In this case, the water retention capacity is given by the ratio of the amount of water absorbed by the sample and after removal of the excess water by centrifuging and the weight of the sample in the normal air-conditioned state, wherein the weight of the remaining amount of water difference of the weight of the sample in the wet state and the weight of the sample in air-conditioned condition.

The water absorption was determined by the following water distribution test: 0.1 ml of water is pipetted onto the hydrophobic sample. The pad is a knitted fabric made of absorbent cellulose material. After 30 seconds, an upper layer is also made of absorbent cellulose material and the wet surface is loaded with a weight for 60 s (area: 26.4 cm ² , overlay: 250.1 g). The water distribution is then determined by weighing the different parts. When using material A as the middle layer, the water is largely released to the absorbent upper and lower layers.

As the experiments show, water retention and moisture absorption are very similar for material A and material B. However, there are big differences in the dynamic water distribution test, which characterizes the water transport property. These differences remain in an advantageous manner even after multiple washes.

Claims (15)

1. A method for creating a washing-resistant hydrophobic treatment for cellulose fibers, comprising the following steps:

   a. applying (100) a hydrophobizing agent to the cellulose fibers in the fiber production step before dyeing in a discontinuous direct dyeing process by immersing the cellulose fibers in a dye uptake bath of an aqueous emulsion containing the hydrophobizing agent, wherein the hydrophobizing agent contains at least one of the following substances as an active substance with the hydrophobizing effect: at least one derivative of the long-chain hydrocarbons, at least one fatty alcohol derivative, at least one fatty amine derivative, at least one derivative of a fatty acid, characterized in that with at least 90 % of the respective molecules thereof present in the hydrophobizing active substance, the number of carbon atoms in the hydrophobic chain amounts to at least 12 carbon atoms;

   b. draining out (200) the dye uptake bath removing the cellulose fibers from the dye uptake bath;

   c. drying (300) the cellulose fibers.
2. The method according to claim 1, also comprising the step of thermal fixation (400) of the hydrophobizing agent on the cellulose fibers after drying (300).
3. The method according to claim 1 or 2, characterized in that the cellulose fibers are designed as flocked fibers and/or the cellulose fibers are bundled as fiber bales and sent as such to the dye uptake bath.
4. The method according to any one of the preceding claims, characterized in that the dye uptake bath is at a temperature of 20 °C to 110 °C, preferably of 30 °C to 80 °C, especially preferably between 40 °C and 60 °C.
5. The method according to any one of the preceding claims, characterized in that the amount of hydrophobizing active substance is between 0.1 % by weight and 10 % by weight, preferably between 0.2 % by weight and 8 % by weight, especially preferably between 0.3 % by weight and 4 % by weight of the total mass of the cellulose fibers to be treated.
6. The method according to any one of the preceding claims, characterized in that the number of carbon atoms in the hydrophobic chain is at least 16, preferably at least 20, most especially preferably at least 24 carbon atoms in at least 90 % of the molecules thereof that are present in the hydrophobizing active substance in the at least one derivative of the long-chain hydrocarbons and/or the at least one fatty acid derivative and/or the at least one fatty alcohol derivative and/or the at least one fatty amine derivative.
7. The method according to any one of the preceding claims, characterized in that the ratio of the volume of the aqueous emulsion to the total mass of the cellulose fibers to be treated is between 0.4 L/kg and 40 L/kg, preferably 1 L/kg to 20 L/kg, especially preferably 5 L/kg to 15 L/kg.
8. The method according to any one of the preceding claims, characterized in that the drying (300) of the cellulose fibers takes place at a temperature of at least 100 °C, in particular between 105 °C and 140 °C, preferably between 110 °C and 120 °C.
9. The method according to any one of the preceding claims, characterized in that the thermal fixation (400) of the hydrophobizing agent on the cellulose fibers takes place at a temperature between 110 °C and 190 °C, preferably between 130 °C and 170 °C, especially preferably between 140 °C and 160 °C.
10. The method according to any one of the preceding claims, characterized in that the dwell time of the cellulose fibers in the treatment bath is between 0.5 min and 180 min, preferably 20 min and 120 min, especially preferably between 60 min and 120 min.
11. The method according to any one of the preceding claims, characterized in that the dye uptake bath is preferably circulated, pumped in circulation and/or stirred during the application (100) of the hydrophobizing agent to the cellulose fibers, wherein the circulation, pumping and/or stirring preferably take place at a reduced shear force, so that the emulsion is not destroyed.
12. The method according to any one of the preceding claims, characterized in that the cellulose fibers have manmade cellulose fibers, in particular viscose fibers, modal fibers and/or lyocell fibers.
13. Cellulose fibers that have been hydrophobized to be washing-resistant by a method according to any one of claims 1 to 12, wherein the cellulose fibers have a dye uptake capacity from an aqueous medium such that the dye uptake capacity is reduced by no more than 20 % in comparison with the dye uptake capacity of the cellulose fibers before being hydrophobized.
14. The cellulose fibers according to claim 13, characterized in that the complete surface of each cellulose fiber has a uniform coating of the hydrophobizing agent, and/or the interior of each cellulose fiber is essentially free of hydrophobizing agent.
15. A textile product, in particular woven, knit, nonwoven, fabric or yarn or twisted yarn produced from at least one or more cellulose fibers according to any one of claims 13 to 14.