WO2011116403A2

WO2011116403A2 - Method for producing a nitrogen-containing polysaccharide

Info

Publication number: WO2011116403A2
Application number: PCT/AT2011/000141
Authority: WO
Inventors: Loan Thi To Vo; Barbora Siroka; Avinash P. Manian; Thomas Bechtold
Original assignee: Universität Innsbruck
Priority date: 2010-03-23
Filing date: 2011-03-22
Publication date: 2011-09-29
Also published as: AT509621A1; EP2549965A2; AT509621B1; WO2011116403A3

Abstract

The invention relates to a mixture of matter containing 10-80% by weight of at least one amide, 10-80% by weight of at least one salt and 1-80% by weight of at least one polyol, and also the use of this mixture of matter for producing a nitrogen-containing polysaccharide from a polysaccharide, and relates to diverse uses of the products thus produced.

Description

Process for the preparation of a nitrogen-containing polysaccharide

The invention relates to a process for the preparation of a nitrogen-containing polysaccharide. Furthermore, the invention relates to a substance mixture for use in such a process. Finally, the invention relates to moldings and processes for the production of such moldings using nitrogen-containing polysaccharides and the use of these polysaccharides.

Among the naturally occurring polymers, polysaccharides are the most commonly occurring. Cellulose is the most widely used natural polymer ever, it has excellent properties and is used in a wide variety of applications. It is one of the main components of wood, of fibers such as flax, cotton and is formed as a bacterial cellulose by microbial processes. From wood, cellulose is made by different processes as pulp for a variety of applications, e.g. Fiber and foil production, paper production provided. The potential of this polymeric material, which is available from natural sources, is correspondingly great, but this can only be deformed and processed by complex processes. For deformation of the material e.g. from the short fiber pulp powder form into a fiber for textile applications or a film (e.g., cellophane), the cellulosic polymers are to be separated by suitable chemical concepts. The very strong inter- and intramolecular hydrogen bonds between the cellulose chains can be opened by suitable methods and regenerated after the forming process, which explains the notion of cellulose regeneration.

The strong hydrogen bonds between the polymer chains are also the cause, therefore, a simple thermal deformation by heating, such as e.g. of synthetic polymers such as polypropylene or polyamide, or simply dissolving in a solvent are not suitable for the deformation of cellulose. Before the theoretical melting of the cellulose, a degradation reaction takes place with simultaneous destruction of the polymer chains.

Solvents and mixtures of solutes that are only capable of swelling the polymeric polysaccharide matrix are referred to as swelling agents. Since such mixtures can not achieve complete dissolution of the polymers, but in particular penetrate into the low-order amorphous regions of a polysaccharide matrix, there is a reversible increase in volume of the undissolved matrix, which decreases again after removal of the swelling agent. For the expert are swelling agents therefore fundamentally different to solvents or solution systems for polysaccharides.

The swelling agent leads to an increase in volume of fibers and usually also to a significant change in the physical properties, e.g. Fiber strength, flexibility, elasticity, etc. From the physico-chemical state, the interactions between the macromolecules and the swelling agent are more favorable than the intermolecular forces between the macromolecules on the one hand and the swelling agent molecules on the other hand. The at least partial penetration of the swelling agent into the polymer structure (and thus the volume increase) is therefore energetically favored. (Source D. Klemm, B. Philipp, T. Heinze, U. Heinze, W. Wagenknecht, Comprehensive Cellulose Chemistry, Vol I and II, Wiley-VCH, 1998, ISBN 3- 527-29413-9, Vol. 1, Page 43, chapter 2.2 Swelling and Dissolution of Cellulose)

In the swelling agent, the two-phase structure (cellulose in the swollen state) and liquid phase remains. In contrast, in solvents capable of dissolving the polymer, a homogeneous single-phase solution of the macromolecular substance is formed as a stable final state. The treatment of cellulosic substrates in solutions of various swelling substances has been extensively studied because of the possibility of changing the structure and reactivity of the cellulose fibers.

Known alkaline treatment solutions may contain alkali ions (Li, Na, K ions), as well as, for example, alkaline earth hydroxides and quaternary ammonium hydroxides are known. The treatment in solvent systems (alcoholic solutions of swelling agents) has also been described in the prior art. Strongly acidic swelling agents such as ortho-phosphoric acid and polyphosphoric acid have also been described as swelling agents.

As swelling neutral solutions, especially liquids from the classes of ionic liquids (eg 1-n-butyl-3-methylimidazolium chloride, 1-ally-3-methylimidazolium chloride or homologous substances or corresponding acetates), the organic swelling agent ( For example, N-methyl-morpholine-N-oxide), the inorganic salts (eg CaCl ₂ , ZnCl ₂ , LiCl, NaSCN, MgCl ₂ ) and more complex mixtures such as LiCl / N, N-dimethylacetamide, NH ₄ Cl - sym-dimethylurea , NaCl / urea serve. The formation of complexes between LiCl and urea is known in the art. Likewise, such solutions can be used as swelling agents for the treatment of cellulosic materials.

The use of glycerol, ethylene glycol, propylene glycol / urea mixtures to plasticize films of regenerated cellulose has been described in the literature (see, e.g., PL 66855). However, these systems merely aim to maintain high humidity in the cellulosic structure, thereby achieving softening effect.

For a targeted deformation of the cellulose e.g. fibers or films require extensive dissolution of the hydrogen bonds between the polymer chains. In accordance with the importance of cellulose, numerous prior art processes have been proposed for the deformation of cellulose. In principle, a distinction can be made between non-derivatizing methods and derivatizing methods.

In the non-derivatizing process, the cellulose is formed by dissolution in a suitable aqueous or nonaqueous solvent system, in which case, for example, NMMO N-methylmorpholine N-oxide or ionic liquids such as 1-n-butyl-3-methylimidazolium acetate important solvents for cellulose should be mentioned. The regeneration of the dissolved cellulose in the desired form is carried out here by extruding the viscous mass through spinnerets or slot dies, and washing out the solvent, whereby fiber or films of regenerated cellulose are obtained. While at NMMO the oxidation effect of the product poses safety risks, the regeneration of washed-out ionic liquids is technically not solved today. Analogously, quaternary ammonium compounds such as N-alkylpyridinium halides are also suitable for dissolving cellulose, disadvantageously requiring high temperatures for producing a melt of these salts.

A closer look at the operation of these solvents reveals that strong interactions between solvent and polysaccharide are required to produce stable solutions. Complex structures / associates form between low-molecular-weight solvent molecules and the long-chain polymer, so that the idea of complex formation between solvent and polymer is also discussed. Accordingly, the classical metal complexes which have been proposed for the solution of the cellulose can also be counted among this group of systems. Important representatives are cuoxam (alkaline copper oxide ammonia solution), EWNN (iron tartaric acid) Caustic soda complex) or Cadoxene (cadmium-ethylenediamine-sodium hydroxide complex). In addition to the limited dissolving power, in particular the high chemical expenditure and the heavy metal content or the toxicity of the solution for a technical implementation is disadvantageous.

Alkali metal salts can also be used to dissolve cellulose using suitable solvents. First and foremost, the system lithium chloride / dimethylacetamide (LiCl / DMAC), which is extensively used in particular in analytical investigations. However, the system's corrosiveness and high cost have prevented a technical use for the formation of cellulose. Similar to these systems, the solvents proposed by Herlinger and Hirt (Chemiefasern / Textilindustrie 37/89, (1987) 788-792) for cellulose, the use of substituted cyclic urea derivatives D EU (dimethylethyleneurea), or DMPU (Dimethylpropülenenharnstoff) in combination with LiCI or LiBr, these solutions having in common is that the liquid phase of DMEU or DMPU is formed in which the Li salt is dissolved. There are no significant amounts of water supplied to the systems, so that these solutions consist essentially of cellulose, LiCl and the aprotic solvent. Even small amounts of water have a detrimental effect on the dissolution properties of the preparation (Potthast A. et al., Cellulose 9 (2002) 41-53).

According to the same physical solution principle, cellulose can be dissolved in solutions of LiCl in hexamethylphosphoramides or 1-methyl-2-pyrrolidinone (DD 214622 A1). Analogously, the known systems consisting of ethylenediamine or hydrazine and thiocyanates are to be regarded as anhydrous basic-reacting solvent systems (Xiao M, Cellulose, 16 (2009) 381-391).

Other non-aqueous solvent systems rely on the use of mixtures of organic solvents, eg, DMSO (dimethyl sulfoxide) and SO ₂ , to which amines are added (Heinze T., Koschella A., Polimeros: Ciencia e Tecnologia, 15 (2005) 84-90).

Similar to the metal complexes or the use of ionic liquids, the resolution is bound to the formation of stable associates or complexes, so that such systems can also be counted among the class of non-derivatizing systems. Analogously, solution systems which use alkali metal hydroxide solutions to dissolve the cellulose work, however, are the limited dissolving power, which only for low molecular weight polymers is sufficient and to mention the regeneration by precipitation of the cellulose with acid as disadvantages.

The use of alkaline aqueous solutions containing alkali metal hydroxides and other organic components such as urea or thiourea has also been described in the literature (Ruan, D., et al., Macromol Biosci., 2004, 4, 1105-1112). Common to these methods is the disadvantage that regeneration of the polymer dissolved in the alkaline solution requires precipitation in acid to neutralize the caustic soda, otherwise technically unacceptable amounts of water would be required to wash out the caustic soda.

Alkaline mixtures of salts, organic solvents with amino compounds, for example ethylenediamine as solvent for cellulose have also been described in the literature (SU 810735).

Also, the use of acidic solvents e.g. Phosphoric acid, or sulfuric acid / polyethylene glycol has been proposed for the dissolution of cellulose (Jasiukaityte E, Cellulose 16, (2009) 393-405). In this process too, either neutralization of the acid or disadvantageously high water consumption must be considered in the production of a regenerated cellulose product.

The non-derivatizing solvents include also the hydrate melts Lil.2 H ₂ 0 inorganic salts, LiN0 _3l LiAcetat, LiCI0 ₄ .3 H ₂ 0, H ₂ 0 LiSCN.2, ZnCl ₂ .4H ₂ 0, Zn (N0 ₃₎ ₂ .x H ₂ 0, FeCl ₃ .6H ₂ 0 and their mixtures with Mg salts Zn salts and thiocyanates and other perchlorates. LiCl is described here merely as a swelling agent (Heinze T., Koschella A., Polimeros: Ciencia e Tecnologia, 15 (2005) 84-90, Leipner et al., Macromol. Chem. Phys., 201 (2000) 2041-2049 Fischer S., et al., Cellulose 10 (2003) 227-236). Due to the present in the melt water of crystallization these systems are added to the aqueous media.

All previously proposed methods therefore have specific disadvantages which have largely prevented the more extensive use of cellulose as a moldable polymer. Exceptions are special developments, such as viscose fibers or lyocell fibers, viscose films or sponges or materials of acetylated celluloses, all of which, however, have specific disadvantages, such as high costs, relatively high chemical emissions or the use of safety-critical chemicals. In derivatizing methods, another compound is produced from the cellulose by chemical conversion, which shows a different dissolving or melting behavior, since the, a dissolution or separation of the chains hindering, hydrogen bonds, were interrupted by chemical modification.

Important examples of such techniques are: viscose fiber production by the xanthate method, cellulose di- and triacetate, methyl cellulose, carboxymethyl cellulose.

Viscose has been used for a long time with great commercial success for producing regenerated cellulose. In this case, cellulose is treated with NaOH and CS ₂ to obtain cellulose xanthate, which in turn is dissolved in a weak NaOH solution to finally obtain the viscose. However, this process is accompanied by the use and emergence of environmentally problematic chemicals such as CS ₂ , H ₂ S and heavy metals.

A useful alternative to the viscose process would therefore be desirable. Although the cuproammonium process based on the solubility of cellulose in copper oxide has been introduced, the use of this process began to decline as early as the early 1960's (Ullmann's Encyclopedia of Industrial Chemistry: Cellulose-3.3 Cuproammonium Fibers). The lyocell method is based on the solution of cellulose in NMMO instead of CS ₂ / NaOH, which minimizes the unpleasant odors and toxic emissions of sulfur-containing gases.

A particular method of derivatization is the preparation of cellulose carbamates which have increased solubility in alkaline solutions. Cellulose carbamates are also known as cellulose aminomethanates, cellulose aminomethanoates or cellulose aminoformates. Cellulose carbamates are advantageous compared to cellulose xanthate because they are more stable and can be transported in a dried state while cellulose xanthogenate is not even transportable in solution. The formation of alkali-soluble cellulose carbamates by reacting urea with alkali-activated cellulose has been extensively described in the literature (US 4,999,425, WO 2004/046198, WO 2003/099871). The preliminary treatment in alkaline swelling agents leads to an improved conversion / but the use of alkaline media is cumbersome and requires a subsequent neutralization. As alkaline swelling agents, alkali metal hydroxides or liquid ammonia have been proposed in the literature (CN 1687137, EP 282 881, DE 19635707, EP 57 105). task This additional swelling pretreatment is to improve the accessibility of the undissolved cellulose structure.

Also, the addition of inorganic or organic acids to improve the reaction between urea and cellulose has been proposed (PL 163049). The preparation of cellulose carbamates is also by reacting cellulose with urea in an inert organic medium, e.g. Toluene, xylo! and ethyl pyridinium bromide as an example of ionic liquids. (DE 19635473; DE 4242437, Cheng et al., Jinxi Huagong 2000, 17 (6), 356-357; Hu et al., 2007, 24 (3), 31-35).

The direct reaction of cellulose with urea e.g. at 200 ° C. or by microwave heating has been proposed in the prior art as a method of producing cellulose carbamate (Ekman et al., Kemia-Kimi 1984 11 (5) 395-7, Vali et al., Koksnes Kimija 1980, 5, 22-4; Guo et al., Macromolecular Rapid Communications 2009 30 (17) 1504-08, CN 101597336). A catalytic effect for the production of cellulose carbamate from cellulose and urea, is attributed to PL 160866 co-salts.

Also, a catalytic acceleration of the reaction between urea and cellulose by magnesium and calcium salts is described in DE 44 07 906, whereby the reaction temperature can be lowered to 120 - 150 ° C.

A combination of alkaline activation with the simultaneous use of inert solvents e.g. 1-methyl-2-pyrrolidone, alcohols or polyethylene glycol as urea solvent is proposed, for example, in WO 2003/054023 and DE 19940393 for the production of cellulose by cellulose pulp. The reaction mixture can also be processed simultaneously by extrusion into fibers, films and other shaped articles (WO 2003/099872). However, the disadvantageous use of alkaline solutions can not be circumvented according to WO 2003/099872.

The use of supercritical C0 ₂ as co-solvent for the reaction between cellulose and urea has also been described, with particular mention being made of higher degrees of substitution with respect to the carbamate function introduced (Yin et al., Carbohydrate Polymers 2007, 67 (2) 147-154 CN 1775810). It is therefore possible to recognize two important basic principles for the preparation of cellulose carbamates, firstly the reaction after previous activation and secondly the reaction in an inert solvent.

Despite the extensive knowledge of the swelling, dissolution and derivatization of cellulose, no suitable process is available in the current state of the art which allows one-stage thermal deformation of the cellulose by using a suitable medium.

The object of the present invention is therefore to remedy this situation and to provide a method and means for carrying out the method so that it is better to make cellulose thermally deformable.

This object is achieved by a method for producing a nitrogen-containing polysaccharide, which is characterized in that the polysaccharide is reacted with an amide in the presence of a salt and a polyol at a temperature of at least 90 ° C.

The process can be carried out using a mixture of substances comprising:

• 10 - 80% by weight of at least one amide

• 10 - 80% by weight of at least one salt

• 1 - 80% by weight of at least one polyol

be optimally realized.

The method according to the invention now provides a possibility for the deformation of cellulose which dispenses with the use of concentrated alkaline or acidic aqueous solutions and allows the formation of the cellulosic matrix in a single-stage treatment process.

The above-mentioned composition contains an amide as a derivatizing agent for the polysaccharide, an ionic component (the salt) as a swelling agent, and a polyol having two objects of serving as a co-solvent for the amide and as a plasticizer for the polysaccharide. Unexpectedly, it has been found that when these materials are used simultaneously, conditions can be created which allow swelling and homogeneous derivatization in one process step, so that thermal deformability of the cellulose polymer can be achieved. The partial derivatization of the polysaccharide takes place at a temperature increase to at least 90 ° C in a direct way.

In this mixture, several processes occur simultaneously, which are swelling, derivatization of the cellulose polymer, plasticization of the polymer and partial softening, especially in the amorphous regions of the polymeric structure.

Frequently, the mixtures according to the invention are not stable at room temperature, but at least one component crystallizes out at room temperature owing to the limited solubility.

It was therefore not obvious to investigate such preparations for their suitability for thermal cellulose deformation, since they are capable of forming a homogeneous solution only at elevated temperature and thus can be used according to the invention.

In the following, advantageous embodiments of the substance mixture and the process are shown:

For the mixture of substances, it is generally advantageous if the water content is less than 10% by weight.

It can be provided that the content of salt is between 10 and 35% by weight, preferably between 10 and 30% by weight, of amide between 10 and 80% by weight and of polyol between 1 and 50% by weight.

Experiments have shown that neutral salts and organic salts are particularly advantageous.

When using neutral salts, the following conditions and amounts have proved to be advantageous: It is advantageous if the content of salt between 10 and 30 wt.% Amide between 10 and 80 wt.% And of polyol between 1 and 50 wt. % is. The salt may e.g. be selected from the group of alkali salts, alkaline earth salts or mixtures thereof.

When using organic salts, the following conditions and amounts have proved to be advantageous: It is advantageous if the content of salt is between 10 and 35% by weight, preferably between 20 and 30% by weight, of amide between 50 and 70% by weight. and on Polyol between 4 and 20 wt.% Is. Preferred organic salts are salts of carboxylic acids. Preferred examples have the general formula (R ¹ - COO) _n M. Preferably, R ^{1 is} selected from the group alkyl, allyl or mixtures thereof, selected from the group of alkali metal, alkaline earth metal or mixtures thereof, where n = 1 when M is an alkali metal and n = 2 when M is an alkaline earth metal.

Both in the embodiments in which the salt is a neutral salt, as well as in the embodiments in which the salt is an organic salt, the following optional configurations may be possible:

In an advantageous embodiment it can be provided that the amide is a carboxylic acid amide, preferably urea or an N-substituted urea. It has turned out to be particularly advantageous if the polyol is also a polyether. In such compounds at least two -OH groups are provided which are in position 1 and TO, i. located at the first and last carbon atom.

Favor is the polyol selected from the group of polyethylene glycols, the polypropylene glycols, copolymers of ethylene glycol and propylene glycol or mixtures thereof selected. Polyols of different chain lengths can be used.

For the method, it is advantageous if the polysaccharide is reacted with a mixture of substances according to the aforementioned type at a temperature of at least 90 ° C. After the preparation of the mixture, the deformation of the cellulose can take place in the temperature range in which the preparation remains homogeneous. This temperature range is 90-260 ° C, and in a preferred embodiment, temperatures of 140-230 ° C are used.

The preferred polysaccharide is cellulose, in which the process works particularly well, and adaptation and optimization of the conditions for other polysaccharides (eg chitosan, alginate, xanthan, pectin) is readily reasonable to one of ordinary skill in the art. For the textile industry, both natural and regenerated, in particular fibrous celluloses can be used. The main task of the process is to increase the nitrogen content of the polysaccharide, ie, if there is still no nitrogen, to bind it chemically or if nitrogen is already present in the polysaccharide, to increase the content of nitrogen. Such modified polysaccharides are well applicable in the textile industry, so that one embodiment may provide that the polysaccharide is a textile or part of a textile. It is then particularly preferred for the textile to contain cotton. As amides in particular carboxylic acid amides, preferably urea or an N-substituted urea have been found to be suitable.

The novel findings prove to be advantageous for the initial formation of a polysaccharide, preferably of cellulose, wherein the polysaccharide is subjected to a process of the aforementioned type and simultaneously brought into the desired shape.

The novel findings also prove to be advantageous for the production of a shaped body, wherein a polysaccharide is reacted with an amide in the presence of a salt and a polyol at a temperature of at least 90 ° C and is brought into the desired shape.

In both cases, the shaping may be e.g. by pressing, extrusion, pressing with rollers or the like.

The degree of substitution (DS) is the number of hydroxyl groups substituted by carbamate per monosaccharide unit. The DS can vary and reach at most the number of OH groups per monosaccharide unit. For cellulose, the maximum DS = 3. A suitable and sufficient DS for the present invention depends on the mode of application and can be changed by selecting the saccharide substrate and the reaction temperature and reaction time.

In one aspect, therefore, the invention relates to shaped articles containing a nitrogen-containing polysaccharide prepared by a process of the aforementioned kind.

Another aspect of the invention relates to the use of a nitrogen-containing polysaccharide prepared by a process of the aforementioned type as an adsorbent. It has been found that such modified polysaccharides have good Adsorptionseigeschaften for liquids and other substances.

Consequently, the use of such modified polysaccharides, for example, as a hygiene product for receiving body fluid on. As examples, diapers, bandages or the like could be mentioned. Further advantages and details are explained below also by way of examples.

A mixture prepared by the process according to the invention preferably contains an ionic component as the swelling agent in a concentration of 10-35% by weight and an amide or urea derivative with 10-80% by weight as derivatizing agent, and a polyol as co-solvent in an amount of 1-10% by weight , The proportion of water in the mixture remains below 10 percent by weight. In a preferred embodiment, the blend contains 20-30 percent by weight of the ionic component, and a urea derivative of 50-70 percent by weight, and a polyol of 4-20 percent.

With knowledge of the present document, it is readily apparent to one of ordinary skill in the art, by attempting to identify other suitable substances as co-solvent, e.g. from the class of polyhydroxy compounds, for example Gyicerin being mentioned here as a representative.

Particularly advantageous is, by the presence of a neutral swelling agent, possible waiver of a preceding alkaline activation of the cellulose, whereby a subsequent washing or neutralization is not essential.

The softening conditions for the polymer depend on the cellulose used, the comminution of the material and the composition of the preparation used. The time to complete melt may be between 1 minute and 20 hours, in a preferred embodiment the time being between 1 and 60 minutes.

It should be noted that in technical extrusion processes by the much faster heat transfer and high shear and much shorter times for a softening of the cellulose mass can be realized.

Urea is preferably used as the amide component, but after appropriate optimization of the formulation it is also possible to use substituted urea derivatives and other carboxamides.

When using urea, a partial derivatization of the cellulose polymer to the cellulose carbamate takes place during the residence time at elevated temperature. Due to the presence of the swelling agent LiCl, a homogeneous and simpler way is achieved Derivatization, compared to the carbamate syntheses described in the prior art, which either waive activating additives or apply the disadvantageous addition of alkali metal hydroxide solutions such as NaOH or other alkaline substances such as NH ₃ . The addition of alkaline activators usually requires their removal in a subsequent washout and neutralization process, which makes these processes more expensive.

As Poiyole Polyethylengylcole can be used with different chain length, also short-chain polyalcohols, polypropylene glycols and block copolymers of propylene glycol and Polyethylengylcol are used.

The added salt component is preferably selected from the group of ionic components which act as swelling agents, alkali or alkaline earth salts being used in one form. In a particularly preferred form, either LiCl or CaCl _{2 is used} as the ionic component in the preparation.

The derivatizing melt thus produced can now be processed into shaped articles by the usual methods, e.g. by extrusion through nozzles or dissolution of the cellulosecarbamathältigen polymer in sodium hydroxide solution and precipitation in an aqueous precipitation bath. If the cellulose carbamate solution is introduced directly into an aqueous solution, cellulose carbamate in amorphous form is obtained.

As the regeneration bath, aqueous solutions or organic solvents, e.g. Serve alcohols.

By extrusion of the melt in the molding, for example, molding methods can be used by injection molding. In an optimized process, the plasticizing components remain in the molding and are no longer washed out.

The inventive method thus represents a one-step method for the production and deformation of cellulosic materials, wherein when using urea as the amide component at the same time an efficient method for the production of cellulose carbamate is provided.

The process can be applied to pulp of various origins, in a preferred embodiment the process is applied to cellulosic textile fabrics applied, in particular textiles are mentioned, which contain at least one cellulose regenerated fiber as a blend component.

Application examples:

The following recipe examples show exemplary composition of suitable treatment mixtures and experimental results on their behavior. The cellulosic material used was a fabric of viscose material. A water-diluted mixture of PEG 2000 (a polyethylene glycol) urea and LiCl was applied to the fabric with a padder. Overall, a fleet absorption of 75-80% of the material weight is realized.

The amount of water required for applying the mixture is then removed by drying at 105 ° C for 40 sec in a laboratory dryer. On the goods then remain reaction mixtures of the following composition:

Table 1: Mass fractions of the mixtures

Based on the weight of the product (cellulose = 100% by weight), the mixtures have the following proportions

The deformation of the materials takes place by the action of heat and pressure. The material samples described below were treated at a pressure of around 1.0 bar for a period of 30 seconds to 2 minutes at temperatures of 150 ° C to 220 ° C.

The formation of the cellulose carbamate can be confirmed on the basis of the N content and the IR spectrum, wherein the nitrogen content increases with the use of said formulations with increasing treatment temperature and treatment time up to about 2 wt.% N from the weight of the material. Thus, for recipes 1-3, about 1% by weight of N is obtained after treatment at 190 ° C. for 2 minutes or 220 ° C. for 30 seconds; for a treatment at 220 ° C. for 2 minutes, formulations 1 1, 6 Wt.% N and in formulation 3 2.0 wt.% N bound in the polymer (this corresponds to a degree of substitution DS of 0.2-0.25).

The deformability of the polymer can be detected and confirmed under the microscope on the change in the fiber and fabric structure as well as on fiber deformations.

Analyzes of the average degree of polymerization, material strength and elongation confirm that no noticeable damage to the cellulosic polymer occurs due to the treatment conditions used.

Comparative tests with formulations in which one of the constituents is missing show no comparable results in fiber formability.

Example with organic salt:

Fig. 1 shows the steps of carbamation.

Fig. 2 shows the nitrogen content in wt.% Of the treated cellulose

(Reaction product) as a function of temperature.

Fig. 3 shows a FTIR-ATR spectrum of (a) untreated cellulose and (b)

Cellulose carbamate (with DS = 0.25).

The treating solution was prepared by mixing polyethylene glycol (20% by weight), urea (60% by weight) and sodium acetate (20% by weight). The molecular weight of polyethylene glycol was varied from 4000 to 6000 from 2000. A sufficient amount of deionized water was added. Viscose fabric stored under standard conditions (20 +/- 2 ° C, 65 + 1-2% RH) for at least 48 hours was impregnated with a pad at the above solution at room temperature under 1 bar pressure at a speed of 1 m / min. Thereafter, the textile was dried in a tenter dryer at 105 ° C for 40 seconds to remove water. Thereafter, the dried textile was treated at 1 bar pressure for 2 min at 100 ° C to 250 ° C. Subsequently, the textile was washed with water until the washing water was colorless. The reaction products were then dried in air under standard conditions (Figure 1). After treatment, the reaction product was assayed for the formation of cellulose carbamate (by nitrogen elemental elemental analysis) and functional groups (by FTIR-ATR) (Figure 2).

The nitrogen content was determined between 0.1 wt.% To about 2 wt.%, Corresponding to a degree of substitution DS of 0.02 to 0.25. The DS increased to 220 ° C and then again slightly to 250 ° C, due to onset of decomposition.

The FTIR-ATR results of the treated cellulose show that a new absorption peak occurs at 1712 cm ^-1 relative to the spectrum without treatment of the cellulose, corresponding to a C-0 stretching vibration of the carbonyl group (C = 0) of the urethane.

Tensile and tensile tests were performed to prove that the treatment of the cellulose had no appreciable effect on the mechanical properties of the cellulose.

The work leading to this invention has been funded under the Grant Agreement No 214015 under the Seventh Framework Program of the European Community FP7 / 2007-2013.

Claims

claims

1. Mixture of substances containing:

a. 10 - 80% by weight of at least one amide

b. 10 - 80% by weight of at least one salt

c. 1 - 80% by weight of at least one polyol.

2. Mixture according to claim 1, characterized in that the water content is less than 10 wt.%.

3. A mixture according to claim 1 or claim 2, characterized in that the salt is a neutral salt.

4. A mixture according to claim 3, characterized in that the salt is selected from the group of alkali metal salts, alkaline earth metal salts or mixtures thereof, more preferably LiCl.

5. A mixture according to claim 3 or claim 4, characterized in that the content of salt between 10 and 30 wt.%, Of amide between 50 and 70 wt.% And of polyol between 4 and 20 wt.% Is.

6. A mixture according to claim 1 or claim 2, characterized in that the salt is an organic salt.

7. A mixture according to claim 6, characterized in that the organic salt is a salt of a carboxylic acid.

8. A mixture according to claim 7, characterized in that the salt of the carboxylic acid has the general formula R ¹ -COOM or (R ¹ -COO) ₂ , wherein R ^{1 is} an alkyl radical, an allyl radical or a mixture thereof and M is an alkali metal or Is alkaline earth metal.

9. A mixture according to any one of claims 6 to 8, characterized in that the content of organic salt 20 to 30 wt.%, Of amide 50 to 70 wt.% And polyol is 4 to 20 wt.%.

10. A mixture according to any one of claims 1 to 9, characterized in that the amide is a carboxylic acid amide, preferably urea or an N-substituted urea.

1 1. A mixture according to any one of claims 1 to 10, characterized in that the polyol is also a polyether.

12. A mixture according to claim 1 1, characterized in that the polyol is selected from the group of polyethylene glycols, the polypropylene glycols, copolymers of ethylene glycol and propylene glycol or mixtures thereof is selected.

13. A method for producing a nitrogen-containing polysaccharide, characterized in that the polysaccharide is reacted with an amide in the presence of an ionic component, preferably a salt, and a polyol at a temperature of at least 90 ° C.

14. A method for producing a nitrogen-containing polysaccharide, characterized in that the polysaccharide is reacted with a mixture of substances according to any one of claims 1 to 12 at a temperature of at least 90 ° C.

15. The method according to claim 13 or 14, characterized in that the polysaccharide is cellulose.

16. The method according to claim 13 to 15, characterized in that the polysaccharide is a textile or part of a textile.

17. The method according to claim 16, characterized in that the textile contains cotton.

18. The method according to any one of claims 13 to 17, characterized in that the amide is a carboxylic acid amide, preferably urea or an N-substituted urea

19. A process for the primary forming of a polysaccharide, preferably of cellulose, characterized in that the polysaccharide is subjected to a process according to any one of claims 13 to 8 and simultaneously brought into the desired shape.

20. A process for producing a shaped body, wherein a polysaccharide is reacted with an amide in the presence of an ionic component, preferably a salt, and a polyol at a temperature of at least 90 ° C and brought into the desired shape.

21. The method according to claim 19 or 20, characterized in that the shaping is carried out by pressing, extrusion, pressing with rollers or the like.

A molded article containing a nitrogen-containing polysaccharide prepared according to any one of claims 3 to 18.

23. Use of a nitrogen-containing polysaccharide prepared by a process according to any one of claims 13 to 18 as an adsorbent.

A sanitary product for receiving body fluid, comprising a nitrogen-containing polysaccharide prepared according to any one of claims 13 to 18.