Polysaccharide fibers and method for producing same

Abstract

The present invention relates to a method for the production of polysaccharide fibers which contain a mixture of cellulose and (1.fwdarw.3)-glucan as a fiber-forming substance, as well as to the fibers made thereby, and to their use.

Claims

1. A method of producing a polysaccharide fiber comprising cellulose and (1.fwdarw.3)-glucan, said method comprising: (i) preparing an alkaline cellulose xanthogenate composition; (ii) combining the alkaline cellulose xanthogenate composition with a composition comprising (1.fwdarw.3)-glucan to provide a spinning solution that comprises a fiber-forming substance, wherein substantially all of the glycosidic bonds of the (1.fwdarw.3)-glucan are (1.fwdarw.3)-glycosidic bonds, and wherein the fiber-forming substance comprises 5% to 45% by weight the (1.fwdarw.3)-glucan; and (iii) extruding the spinning solution to produce the polysaccharide fiber.

2. The method of claim 1, wherein the polysaccharide fiber is a modal fiber.

3. The method of claim 1, wherein the polysaccharide fiber is a staple fiber or a continuous filament.

4. A polysaccharide fiber produced according to the method of claim 1.

5. The polysaccharide fiber of claim 4, wherein the polysaccharide fiber is a staple fiber or a continuous filament.

6. A textile product comprising the polysaccharide fiber of claim 4, wherein the textile product is selected from the group consisting of yarns, woven fabrics, and knitted fabrics.

7. A product comprising the polysaccharide fiber of claim 4, wherein the product is a nonwoven, hygiene article, or paper.

8. The textile product of claim 6, wherein the polysaccharide fiber is a staple fiber or a continuous filament.

9. The product of claim 7, wherein the product is said hygiene article, wherein the hygiene article is selected from the group consisting of tampons, panty liners, and diapers.

10. The product of claim 7, wherein the polysaccharide fiber is a staple fiber or a continuous filament.

11. The method of claim 1, further comprising (iv) stretching the polysaccharide fiber.

12. The method of claim 1, wherein the weight-average degree of polymerization (DPw) of the (1.fwdarw.3)-glucan is between 200 and 2000.

13. The method of claim 12, wherein the DPw of the (1.fwdarw.3)-glucan is between 500 and 1000.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

(1) FIG. 1 is a schematic depicting the production process for a fiber made in accordance with the present invention.

DESCRIPTION OF THE INVENTION

(2) The above described object is solved by a method for the production of a polysaccharide fiber using a xanthogenate process, wherein the fiber-forming substance is a mixture of cellulose and (1.fwdarw.3)-glucan. The (1.fwdarw.3)-glucan can be added at various locations of the process in the form of an (1.fwdarw.3)-glucan-containing aqueous sodium hydroxide solution. For the purposes of the present invention, a fiber produced in this way shall also be referred to as viscose or modal fiber even though, in addition to cellulose, it also contains another fiber-forming polysaccharide, namely, said (1.fwdarw.3)-glucan.

(3) For the purposes of the present invention, the term fiber shall comprise both staple fibers having a defined staple length and continuous filaments. All principles of the invention that are described hereinafter generally apply to both staple fibers and continuous filaments.

(4) The single fiber titer of the inventive fibers can be between 0.1 and 10 dtex. Preferably, it is between 0.5 and 6.5 dtex, and more preferably between 0.9 and 6.0 dtex. In the case of staple fibers, the staple length is usually between 0.5 and 120 mm, preferably between 20 and 70 mm, and more preferably between 35 and 60 mm. In the case of continuous filaments, the number of individual filaments in the filament yarn is between 50 and 10,000, preferably between 50 and 3,000.

(5) The (1.fwdarw.3)-glucan can be prepared by bringing an aqueous solution of saccharose into contact with glucosyltransferase (GtfJ) isolated from Streptococcus salivarius (Simpson et al., Microbiology, vol. 41, pp 1451-1460 (1995)).

(6) Preferred embodiments of the inventive method are the variants of the viscose process generally known to those skilled in the art as well as of a viscose process modified for the production of modal fibers.

(7) In a preferred embodiment of the method according to the invention, at least 90% of the (1.fwdarw.3)-glucan are hexose units and at least 50% of the hexose units are linked via (1.fwdarw.3)-glycosidic bonds.

(8) The method for the production of the inventive fiber consists of the following steps (also see FIG. 1):

(9) 1. Preparing the alkali cellulose, and its xanthogenation;

(10) 2a. Adding (1.fwdarw.3)-glucan together with the dissolving liquor (FIG. 1, addition location V1), preferably by addition into an appropriate agitating vessel;

(11) or

(12) 2b. Dissolving the xanthogenate in dissolving liquor and addition of (1.fwdarw.3)-glucan in alkaline solution between the dissolver and the spinning machine (FIG. 1, addition location V2), preferably by an appropriate inline mixing unit known to those skilled in the art;

(13) 3. Extruding the (1.fwdarw.3)-glucan-containing spinning solution through a spinneret into a sulfuric acid spin bath, stretching the fibers, and post-treatment.

(14) The concentration of the fiber-forming substance in the spinning solution can be between 4 and 15% by weight, preferably it is between 5.5 and 12% by weight.

(15) In the inventive method, the fiber-forming substance can contain between 1 and 99% by weight of (1.fwdarw.3)-glucan. Preferred is a content of the (1.fwdarw.3)-glucan between 5 and 45% by weight. Below 5% by weight of (1.fwdarw.3)-glucan, the economic benefit of the added (1.fwdarw.3)-glucan is too low for typical types of use of the inventive fibers; above 45%, competing reactions for the CS.sub.2 in the spinning solution become too intensive, and the spinnability of the solution decreases significantly. However, under certain conditions and/or for certain types of use of the inventive fibers, both limits may be exceeded; the scope of the present invention expressly also includes fibers having an (1.fwdarw.3)-glucan content between 1 and 5% by weight and between 45 and 99% by weight, respectively.

(16) Preferably, the remaining part of the fiber-forming substance consists substantially of cellulose. As used in this context, substantially means that low quantities of other substances can be present which primarily originate from the cellulosic raw material, generally from said pulp. Such other substances include primarily hemicellulose and other saccharides, lignin residues, or the like. They are also contained in commercially available viscose and modal fibers.

(17) However, the scope of the present invention shall expressly also include such fibers that, in addition to the constituents mentioned so far, also contain other polysaccharides or functional additives as generally known in the nonwoven and textile industries.

(18) The degree of polymerization of the (1.fwdarw.3) glucan employed in the method according to the invention, expressed as weight average DP.sub.w, can be between 200 and 2000; values between 500 and 1000 are preferred.

(19) A polysaccharide fiber produced by using a xanthogenate process and containing cellulose and (1.fwdarw.3)-glucan as fiber-forming substances is also the subject-matter of the present invention. Preferably, the fiber-forming substance contains between 1 and 99% by weight of (1.fwdarw.3)-glucan and more preferably between 5 and 45% by weight of (1.fwdarw.3)-glucan.

(20) In a preferred embodiment, at least 90% of the (1.fwdarw.3)-glucan of the inventive polysaccharide fiber are hexose units and at least 50% of the hexose units are linked via (1.fwdarw.3)-glycosidic bonds.

(21) The use of the inventive fibers for the production of various dry-laid and wet-laid papers, nonwovens, hygiene articles such as tampons, panty liners, and diapers, and other nonwovens, especially absorbent nonwoven products, but also of textile products such as yarns, woven fabrics, or knitted fabrics is also the subject-matter of the present invention.

(22) The invention will be described below with reference to examples. However, the invention is not expressly limited to these examples but also includes all other embodiments that are based on the same inventive concept.

EXAMPLES

(23) The degree of polymerization of the (1.fwdarw.3)-glucans was determined by means of GPC in DMAc/LiCl. Subsequently, it is always the weight average of the degree of polymerization (DP.sub.w) that is specified.

Example 1

(24) A viscose xanthogenate containing 29.8% by weight of cellulose, 14.9% by weight of alkali, and 8% by weight of sulfur was reacted in a dissolving unit with a first dissolving liquor containing 4.5% by weight of NaOH and then with a second dissolving liquor containing 9% by weight of (1.fwdarw.3)-glucan and 4.5% by weight of NaOH and finally with water. The viscose obtained in this way contains 9% by weight of fiber-forming material, 5.20% by weight of alkali, and 2.4% by weight of sulfur (calculated under the assumption that there are 100% by weight of cellulose as a fiber-forming material), with a ripeness index of 14 Hottenroth and a falling ball viscosity of 80 seconds (determined according to the Zellcheming Leaflet III/5/E). Viscose solutions with 10 and 25% of (1.fwdarw.3)-glucan were prepared. These glucan quantities were related to the proportion of the (1.fwdarw.3)-glucan in the fiber-forming substance. These viscose types contain 2.2% by weight of sulfur (10% by weight of glucan and 90% by weight of cellulose as fiber-forming materials) and 1.8% by weight of sulfur (25% by weight of glucan and 75% by weight of cellulose as fiber-forming materials), respectively. By using a spinneret, the solution was extruded into a regeneration bath containing 100 g/l of sulfuric acid, 330 g/l of sodium sulfate, and 15 g/l of zinc sulfate. The spinneret had 1053 perforations with a diameter of 50 m. 0.5% by weight of a nitrogen-containing auxiliary agent were added to the viscose spinning solution. In order to achieve adequate fiber strength, stretching by approx. 75% was carried out in the second bath (92 C., 15 g/l of H.sub.2SO.sub.4). The draw-off velocity was 50 m/min.

(25) In a reference example 1, the viscose from Example 1 was spun into fibers without the addition of the glucan/NaOH solution, but otherwise in the same conditions as in Example 1.

(26) The properties of the obtained fibers are listed in Table 1.

Example 2

(27) A viscose containing 8.70% by weight of cellulose, 5.20% by weight of alkali, and 2.3% by weight of sulfur, with a ripeness index of 15 Hottenroth and a falling ball viscosity of 75 seconds (determined according to the Zellcheming Leaflet III/5/E), was, by means of a spinneret, extruded into a regeneration bath containing 100 g/l of sulfuric acid, 310 g/l of sodium sulfate, and 15 g/l of zinc sulfate. The spinneret had 1053 perforations with a diameter of 50 m. 0.5% by weight of a nitrogen-containing auxiliary agent were added to the viscose spinning solution. In order to achieve adequate fiber strength, stretching by approx. 75% was carried out in the second bath (92 C., 15 g/l of H.sub.2SO.sub.4). The draw-off velocity was 50 m/min.

(28) By using a positive displacement pump, various weight/weight percentages of a (1.fwdarw.3)-glucan solution (prepared with 5% by weight of NaOH, 8% by weight of (1.fwdarw.3)-glucan) were added to the viscose solution upstream from the spinneret, and fibers having 5, 10, 15, and 30% of glucan were produced (FIG. 1, V2). These glucan quantities were related to the mass fraction of the (1.fwdarw.3)-glucan in the fiber-forming substance.

(29) In a reference example 2, the viscose from Example 2 was spun into fibers without the addition of the glucan/NaOH solution, but otherwise in the same conditions as in Example 2.

(30) The properties of the obtained fibers are listed in Table 1.

Example 3

(31) A modal viscose containing 6.0% by weight of cellulose, 6.20% by weight of alkali, and 1.8% by weight of sulfur, with a gamma value of 65 and a falling ball viscosity of 130 seconds (determined according to the Zellcheming Leaflet III/5/E) was, by means of a spinneret, extruded into a regeneration bath containing 72 g/l of sulfuric acid, 115 g/l of sodium sulfate, and 55 g/l of zinc sulfate. The spinneret had 1053 perforations with a diameter of 45 m. 2.5% by weight of a nitrogen-containing auxiliary agent were added to the viscose spinning solution. In order to achieve adequate fiber strength, stretching by approx. 115% was carried out in the second bath (92 C., 15 g/l of H.sub.2SO.sub.4). The draw-off velocity was 50 m/min.

(32) By using a positive displacement pump, various weight/weight percentages of a (1.fwdarw.3)-glucan solution (prepared with 5% by weight of NaOH, 4.5% by weight of (1.fwdarw.3)-glucan) were added to the viscose solution upstream from the spinneret, and fibers having 5 and 15% of glucan were produced. These glucan quantities were related to the mass fraction of the (1.fwdarw.3)-glucan in the fiber-forming substance.

(33) In a reference example 3, the viscose from Example 3 was spun into fibers without the addition of the glucan/NaOH solution, but otherwise in the same conditions as in Example 3.

(34) The properties of the obtained fibers are listed in Table 1.

(35) TABLE-US-00001 TABLE 1 quantity of glucan titer FFk FDk FFn FDn example additive % dtex cN/tex % cN/tex % reference none 1.7 27.4 16.2 15.7 16.8 example 1 1a glucan 10 1.7 27.4 16.5 15.0 17.1 DP.sub.W800 1b glucan 25 1.7 21.9 14.2 12.0 16.3 DP.sub.W800 reference none 1.3 29.6 15.8 17.4 16.6 example 2 2a glucan 5 1.3 29.2 16.1 16.0 17.7 DP.sub.W 800 2b glucan 10 1.3 28.6 17.9 14.9 21.1 DP.sub.W 800 2c glucan 15 1.3 26.1 18.1 12.7 21.1 DP.sub.W 800 2c glucan 30 1.3 23.6 19.4 12.1 20.1 DP.sub.W 800 reference none 1.3 38.8 12.6 22.7 13.0 example 3 3a glucan 5 1.3 37.6 13.3 22.1 14.3 DP.sub.W 1000 3b glucan 15 1.3 36.2 13.4 20.3 13.9 DP.sub.W 1000 FFk fiber strength, conditioned FDk fiber elongation, conditioned FFn fiber strength, wet FDn fiber elongation, wet