WO2014201479A1

WO2014201479A1 - New environmentally friendly method for producing sponges and sponge cloths from polysaccharides

Info

Publication number: WO2014201479A1
Application number: PCT/AT2014/000120
Authority: WO
Inventors: Gregor Kraft; Gert Kroner; Thomas Röder
Original assignee: Lenzing Ag
Priority date: 2013-06-19
Filing date: 2014-06-13
Publication date: 2014-12-24
Also published as: AT514473B1; AT514473A1

Abstract

The invention relates to a modified viscose process for producing porous shaped bodies that contain α(1→3) glucan as a structure-forming substance, and to the porous shaped bodies thus produced.

Description

New environmentally friendly process for producing sponges and sponges from polysaccharides

The present invention relates to a process for the preparation of

spongy moldings using a modified

Viscous method of a (1 - 3) -glucan be prepared.

State of the art

The production of sponge structures by the viscose process has been known for decades. As starting material from renewable raw materials recoverable polysaccharides, especially cellulose, are used.

Alternative polysaccharides, such as the (deacetylated) chitin described in JP2007197649 (A), play only a very minor role.

The production of regenerated cellulose sponges after the

Viscose process is done by mixing the alkaline

Cellulose xanthate solution with at least one pore-forming agent. In practice, water-soluble salts such as sodium or potassium chloride or magnesium or sodium sulfate have proven particularly useful, the resulting pore structure and thus also the density of the obtained

Sponges are essentially determined by the grain size and the particle size distribution of the salts used. The decahydrate of sodium sulfate, also called Glauber's salt, is used particularly frequently. This decomposes at 32 ° C with elimination of its water of crystallization, in which dissolves the sodium sulfate. This process is optically called melting of the

Sodium sulfate decahydrate perceived and therefore often referred to as such. A corresponding process for producing artificial regenerated cellulose sponges which resemble in their porosity those of natural sponges using agglomerates of compressed sodium sulfate decahydrate with small amounts of anhydrous sodium sulfate as a pore-forming substance is described in DE1569226 (A1). In principle, in addition to salts, any other readily soluble or meltable substances, including water-soluble polymers (JP2007197649 (A) or soluble at elevated temperatures, gelatinous particles,

for example, from gelatin (JP2000186166 (A)), propellant, z. B.

gas-forming substances such as aluminum powder (GB1005569 (A)), or gases can be used as a pore-forming agent. Thus, JP2001 139718 (A) has the production of cellulosic sponges by introducing air bubbles in viscose and subsequent heating to the content.

The shaping can be carried out continuously by extruding the viscose,

for example, on perforated endless belts, done. Such processes are used for the production of sponge cloths. To regenerate the cellulose, the conveyor belts loaded with the extruded viscose mass are passed through tempered alkaline or acid baths, the salts used as pore formers being dissolved. extruded

Viscose pastes can also be thermally, for example by heating by means of alternating current or by treatment with hot liquids, for. B.

Hot water or sodium sulfate-containing solutions to be regenerated. GB1278586 (A) describes such a process, wherein in a first step the Glauber's salt crystals contained in the viscose mass are melted by passage of alternating current. Subsequently, the cellulose is completely regenerated by treatment with a hot liquid, preferably by spraying with hot acidic solution.

Block sponges are prepared in a batchwise manner by filling any shaped article with the viscous masses. The regeneration of the molding compositions is possible in a similar manner as in the above-outlined continuous process, namely by chemical means, for. By acid treatment, or by microwave heating, as described in KR830001030 (A). For complete regeneration of the cellulose, a treatment with aqueous, acidic solution can be connected in this process variant. Any existing salt-form pore formers can be removed by washing with water or appropriate washing solutions. The addition of textile reinforcing fibers, including natural cellulosic fibers such as hemp, jute or cotton or man-made cellulosic fibers such as lyocell or viscose fibers, or the introduction of textile fabrics such as fabrics or nets, improve the mechanical properties of regenerated cellulose sponges. It is also possible to dye the viscose composition, for example by mixing in color pigments. The

DE103391 13 (A1) describes, with the aid of reactive dyes, uniformly dyed sponge cloths which are distinguished by the same coloration of the regenerated cellulose and the cotton fibers used for reinforcement. Furthermore, processes for the modification of cellulose sponges are known with the aim to give them additional functional properties.

It is conceivable, inter alia, the incorporation of biocidal, fungicidal and / or antibacterial substances, but also the addition of components with ion-exchanging properties to viscose. The incorporation of chitosan can provide regenerated cellulose sponges with improved absorptive, antibacterial and deodorizing properties (KR20000033143 (A)).

Despite its known drawbacks, the viscose process is still the only commercially used process for producing artificial cellulose sponges. Alternative methods such as the amine oxide method (CN101569757 (A), AT502363 (A1), US7189667 (B1), JPH1 1279323 (A)) or methods using ionic liquids as the direct solvent for cellulose (CN101792538 (A), WO2008087026 (A1)) have despite intensive research and development work to date no large-scale

Implementation experienced.

US 7,000,000 describes fibers obtained by spinning a solution of polysaccharides consisting essentially of hexose repeat units linked via a (1 → 3) glycosidic linkages. These polysaccharides can be prepared by contacting an aqueous solution of sucrose with glucosyltransferase (GtfJ) isolated from Streptococcus salivarius (Simpson et al. Microbiology, vol 41, pp 1451-1460 (1995)). "Substantially" in this context means that sporadia may occur occasionally within the polysaccharide chains at which other binding configurations occur.These polysaccharides are to be considered for the purposes of the present invention as "a (1-3) -glucan ".

According to US Pat. No. 7,000,000, the cx (1 → 3) -glucan is to be derivatized, preferably acetylated. The solvent is preferably an organic acid, an organic halogen compound, a fluorinated alcohol or a mixture of such components. These solvents are expensive and expensive to regenerate.

However, investigations have also shown that a (1- »3) -glucans are soluble in dilute sodium hydroxide solution (about 4 to 5.5%).

task

The object was over this prior art is spongy, d. H. porous moldings consisting of a glucose-containing polysaccharide, as well as to provide an environmentally improved process for their preparation.

The polysaccharide raw material should be cheap and that

Processing method should already be established on an industrial scale and

be economically feasible and on existing facilities.

Description of the invention

The solution to the above-described problem consists in a new process for producing a porous shaped body, the

structure-forming substance (1 -> 3) -glucan, consisting of the following steps: a. Preparation of an alkaline, a (1-> 3) -glucan-containing

polysaccharide; b. Addition and mixing of CS2 c. Addition of pore images, dyes and optionally further

Additives (e.g., biocides or reinforcing fibers) d. Shaping the mass (e.g., by extrusion on perforated

Endless belts or filling of molds) e. Coagulation and regeneration of the mass

The process according to the invention is a modified viscose process. The devices suitable for carrying out these steps and the general process conditions are in principle known to the person skilled in the art from US Pat

Viscose method known.

Thus, a porous shaped body having a sponge structure can be produced, wherein a (1 → 3) -glucan-containing sodium hydroxide solution is mixed only with small amounts of carbon disulfide (CS2). Surprisingly, it has been found that in step b. to be added CS2 amount in

inventive method can be significantly lower than in the

Viscose method of the prior art. The process is thus clearly different from existing methods of manufacturing

Viscose sponges.

In the following, the term "sponge" can also be used for shaped bodies having a porous structure, and such a porous structure can therefore also be termed "sponge-like".

For the purposes of this invention, "structure-forming substance" is to be understood as meaning the homogeneous, solid material of the molding material surrounding the pores

Embodiments of the invention still contain reinforcing materials such as fibers or fabrics, but for the purposes of this invention these reinforcing materials are not to be included in the structure-forming substance. The a (1-> 3) -glucan can be prepared by contacting an aqueous solution of sucrose with glucosyltransferase (GtfJ) isolated from Streptococcus salivarius (Simpson et al., Microbiology, vol 41, pp 1451-1460 ( 1995)).

In a preferred embodiment of the process according to the invention, at least 90% of the a (1 → 3) -glucan consists of hexose units and at least 50% of the hexose units are linked by a (1 → 3) -glycosidic bonds.

In the process according to the invention, the structure-forming substance contains between 20 and 100% by weight of a (1- »3) -glucan. In addition to the ot (1 - 3) -glucan, the in step a. solution also contain cellulose. Pulp is preferably used as cellulosic raw material. However, in principle any other cellulosic raw material suitable for viscose processes is suitable for this purpose, for example cotton linters, recycled old textiles, waste paper or the like.

In a preferred embodiment of the process according to the invention, the structure-forming substance contains 100% by weight of (1-3) glucan.

The concentration of the structure-forming substance in the polymer solution may be between 4 and 15% by weight; preferably 5.5 to 12 wt .-%.

The degree of polymerization of the α (1 -> 3) glucan used in the process according to the invention, expressed as weight average DP _W , can be between 200 and 2000; values between 800 and 1500 are preferred.

If necessary, after step b. a short Nachreife, filtration and / or venting of the polysaccharide solution.

As pore-forming agents, certain salts such as Glauber's salt, sodium or potassium chloride, magnesium or sodium sulfate, other readily soluble or meltable substances, including water-soluble polymers or gelatinous particles soluble at elevated temperatures, for example Gelatin, propellant such. B. gas-forming substances such as aluminum powder or gases are used. The resulting pore structure and thus ultimately the density of the sponges obtained depends essentially on the grain size and the particle size distribution of the salts used. A preferred pore-forming agent is Glauber's salt.

The porous shaped body according to the invention may contain a reinforcing material to improve its properties. This

Reinforcing material may be made of fibers, for example

Short cut fibers, which are the polysaccharide solution in

inventive method are added. This gives a shaped body in which the reinforcing fibers are distributed throughout the structure-forming material.

Another embodiment of the invention is that

Polysaccharide solution applied to a sheet-like reinforcing material, preferably on a textile fabric, so that this reinforcing material surrounds the porous shaped body according to the invention substantially on its outer side. A variant of this embodiment is to apply the polysaccharide solution so that the planar

Reinforcing material is located inside the porous molding.

The textile fabric can be, for example, a dry or wet-laid paper or another nonwoven, but also a woven, knitted or knitted fabric. Basically, of course, foils or thicker, rigid plates of almost any materials as a flat

Reinforcement possible.

Combinations of several of the above-mentioned reinforcing materials in the same shaped body are possible and are included in the invention.

The invention also relates to a porous shaped body, as

structure-forming substance u (1 -> 3) -glucan. This shaped body can also be referred to as a sponge. The structure-forming substance contains between 20 and 100 wt .-%, preferably 100 wt .-% <x (1 -> 3) -glucan.

In a preferred embodiment, at least 90% of the a (1-3) -glucan consists of hexose units and at least 50% of the hexose units are linked by a (1-> 3) -glycosidic bonds.

In a preferred embodiment, the shaped body contains cellulose as further structure-forming substance.

In a preferred embodiment, the inventive

Shaped body a reinforcing material, as already described above.

The shaped bodies according to the invention can be used as sponges or

Sponge cloths of all kinds are used.

In the following the invention will be described by way of examples. However, the invention is expressly not limited to these examples, but includes all other embodiments based on the same inventive concept.

Examples

The degree of polymerization of a (1 -> 3) -glucans was determined by GPC in

DMAc / LiCI determined. In the following, the weight average of the

Degree of polymerization (DP _W ) indicated.

Example 1 :

An aqueous glucan solution containing 9% by weight of a (1- »3) -glucan with a DP _W of 1000 and 4.7% by weight of NaOH was mixed with 15% by weight of CS 2

(Weight percent based on glucan content) implemented. The viscose thus prepared contained 8.9 wt .-% structure-forming material, 4.6 wt .-% NaOH and 1, 1 wt .-% sulfur. This viscose solution was 900 wt .-%

Glauber's salt, based on glucan content, added and mixed.

In addition, the solution as reinforcing fibers was still 25 wt .-% Lyocell fibers, based on glucan content, added with a cut length of 2-3 mm.

The sponge raw material was extruded on a fine-meshed grid, coagulated with hot water (97 ° C) and then with a

Sulfuric acid bath regenerated. During coagulation and regeneration, the Glauber's salt is partially melted and washed out. Thereafter, the porous structure was washed and dried.

Example 2:

An aqueous glucan solution containing 9.5% a (1-3) glucan with a DP _W of 1000 and 4.7 wt% NaOH was mixed with 18 wt% CS2

(Weight percent based on glucan content) implemented. The viscose thus prepared contained 9.3 wt .-% structure-forming material and 4.6 wt .-% NaOH and 1, 4 wt .-% sulfur. 500% by weight Glauber's salt, based on glucan content, was added to this viscose solution and mixed in.

In addition, 25% by weight of lyocell fibers, based on glucan content, were added to the solution as reinforcing fibers with a cutting length of 2-3 mm.

The sponge raw material was extruded onto a fine-meshed grid, coagulated with an acidic sodium sulfate solution (400 g / l Na 2 SO 4) and at a temperature> 95 ° C and regenerated. During coagulation and

Regeneration, the Glauber salt is partially melted and

washed out. Thereafter, the porous structure was washed and dried.

Claims

Claims / Claims

1 . A process for producing a porous shaped body whose structure-forming substance contains a (1-3) -glucan, comprising the steps of: a. Preparation of an alkaline, a (1 → 3) -glucan-containing polysaccharide solution,

b. Adding and mixing CS2,

c. Addition of pore images, dyes and optionally further additives,

d. Shaping the mass,

e. Coagulation and regeneration of the mass.

2. The method of claim 1, wherein the structure-forming substance between 20 and 100 wt .-%, preferably 100 wt .-% a (1 - »3) -Glucan contains.

3. The method of claim 1, wherein the method is a modified viscose method.

4. The method of claim 1, wherein the oc (1 -> 3) -glucan consists of at least 90% hexose units and at least 50% of the hexose units are linked by x (1-3) glycosidic bonds.

5. The method of claim 1, wherein the pore-forming agent is Glauber's salt

6. The method of claim 1, wherein the shaped body contains as further structure-forming substance cellulose.

7. The method of claim 1, wherein the viscose solution reinforcing material in the form of fibers, preferably short cut fibers added.

8. The method according to claim 1, wherein the viscose solution is applied to a sheet-like reinforcing material, preferably to a textile fabric.

9. porous shaped body, characterized in that it contains as structure-forming substance (1 -> 3) -glucan.

10. Porous shaped body according to claim 9, wherein the structure-forming substance contains between 20 and 100 wt .-%, preferably 100 wt .-% <x (1 -> 3) glucan.

1 1. Porous shaped body according to claim 9, wherein the ot (1- »3) -glucan consists of at least 90% of hexose units and at least 50% of the hexose units are linked by a (1 → 3) -glycosidic bonds.

12. Porous shaped body according to claim 9, wherein the shaped body contains as further structure-forming substance cellulose.

13. Porous shaped article according to claim 9, wherein the shaped body contains a reinforcing material.

14. Porous molding according to claim 13, wherein the reinforcing material consists of fibers, preferably short cut fibers, and / or a textile

Sheet consists.