WO2004081267A1

WO2004081267A1 - The method of making modified cellulose fibers

Info

Publication number: WO2004081267A1
Application number: PCT/PL2003/000060
Authority: WO
Inventors: Bogumil Laszkiewicz; Piotr Kulpinski; Barbara Niekraszewicz; Piotr Czarnecki; Marcin Rubacha; Maria Okraska; Jolanta Jedrzejczak; Bogdan Peczek; Ryszard Kozlowski; Jerzy Mankowski
Original assignee: Politechnika Lódzka; Instytut Wlokien Naturalnych
Priority date: 2003-03-10
Filing date: 2003-06-25
Publication date: 2004-09-23
Also published as: EP1601824A1; DE60311324T2; DE60311324D1; PL201205B1; PL359080A1; ATE351933T1; EP1601824B1

Abstract

The method of making modified cellulose fibers from cellulose solution in N-methylmorpholine-N-oxide, which involves mixing ccllulose with aqueous N-methylmorpholine-N-oxide, evaporating and filtration of the spinning solution subsequently forced through the holes in the spinning nozzle into the aqueous spinning bath, finally rinsing, drying and conditioning, is described by the fact that modifying substances such as ceramic oxides, metal oxides or their mixtures, if necessary containing additional surfactants, carbon, if necessary modified with silver, bactericidal agents, acid-base indicators, thermo chromic dyes with nano- or supra molecular break-up are added into the cellulose, the solvent or the spinning solution.

Description

The method of making modified cellulose fibers.

The subject of this invention is the method of making modified cellulose fibers from cellulose solution in N-methylmorpholine-N-oxide .

The common method to make cellulose fibers from cellulose solution in N- methylmorpholine-N-oxide involves mixing cellulose with aqueous N-methylmorpholine-N- oxide, evaporating excess water from the cellulose solution, filtration of the spinning solution which is forced through the holes in the spinning nozzle into the airspace, subsequently followed by water spinning bath, drying and conditioning. In order to make fibers with modified properties, some modifying substances such as titan dioxide, organic or inorganic dyes in the shape of molecules above 1 nm in diameter are added into the spinning solution.

The method of making modified cellulose fibers from cellulose solutions in N- methylmorpholine-N-oxide, involving mixing the cellulose with aqueous NMMO solution, evaporating of the originated cellulose solution until 12-20 weight % cellulose content and less than 13.3 weight % water are left herein, filtration of the spinning solution, forcing through the nozzles into the airspace, from which it is led into the aqueous spinning bath, finally rinsing, drying and conditioning by means of adding modifying substances, according to the principles of this invention, is described by the fact that modifying substances such as ceramic oxides, metal oxides or their mixtures, if necessary containing additional surfactants, carbon, if necessary modified with silver, bactericidal agents, acid-base indicators, thermochromic dyes with nano- or supramolecular break-up are added to the cellulose, to the solvent-or^~to^"the^~spinning"solution in^~proportiOn^~not bigger than-10 weight- % in ratio-to^~the cellulose solvent. Ceramic oxides, advantageously silicon dioxide, metal oxides or their mixtures are used in the shape of powder or its suspended matter in water or aqueous solution in NMMO. Carbon is used in the shape of nanotubes. Phenolphthalein or thymol blue are advantageously used as acid base indicators.

In the method according to the present invention cellulose fibers of specific properties are made relatively simply and easily. The method improves some of the physico-mechanical properties of the fibers at the same time.

The method of the present invention is more thoroughly illustrated by the examples given below, which do not limit its range. Example I.

60 cellulose parts by weight with the degree of polymerization of 800 comprising 8% humidity by weight were introduced into the crusher connected with the vacuum pump and equipped with indirect heating; thereto subsequently 720 parts by weight of 50% aqueous NMMO solution and 20 parts by weight of 30% aqueous water suspension of silicon dioxide with nanomolecular break-up were added, the molecules diameter being 7 nm. Having set in motion the crusher mixers, the vacuum pump therein was switched on, and to start with the crusher was heated till the inside temperature reached 100° C, subsequently the temperature inside the crusher was raised till it reached 130° C.

After approximately 60 minutes the water content in the system cellulose-NMMO-water diminished to 10 weight %, the cellulose was thoroughly solved, and the pulp in the crusher became light brown in color, and it had viscosity 1300 Pa x s. The spinning solution made by this method contained 15% cellulose by weight, having been thoroughly filtered by acid resisting screen unit it was forced into the spinning head of worm spinning frame, where it was forced through the 0,16 mm holes in the spinning nozzle at temperature 100°C, placed 20 mm above the spinning bath, into the aqueous spinning bath of 80°C comprising 4% NMMO by weight. The formed fibers were rinsed in the rinsing bath of 80° C, taken up on the reel with the speed of 80 m/min, subsequently dried and conditioned.

The received fibers were circular in section, white and lustreless, tensile strength being 32 cN/tex, elongation 12 % and fibrillization 2-3, whereas the fibrillization of unmodified fibers is 6.

Example II.

Aqueous supension of silicon dioxide SiO₂ with nanomolecular break up, the molecules diameter being 50 nm, was introduced into the cellulose solution in NMMO, prepared in the same conditions as in Example I, in such an amount that the SiO content was 3 weight % in ratio to the cellulose weight, and the whole lot was mixed. The received spinning solution was filtered as in Example I, subsequently at temperature 110°C forced through the holes in the spinning nozzle, placed 20 mm above the spinning bath, into the spinning bath as in Example I. The next step was as in Example I. The speed of fiber forming was 120 m/ min. The received fibers were circular in section, tensile strength being 36 cN/tex, elongation 13 % and fibrillization 3-4. Example III.

The spinning solution was prepared as in Example I, but at the same time, while dissolving the cellulose, aqueous supension of silicon dioxide SiO₂ with nanomolecular break up ( the molecules diameter being 78 nm), was added to the crusher in such quantity that SiO₂ content was equal to 5 weight % in ratio to the cellulose by weight. At the same time the surfactant under the trade name Berol V-4026 was introduced along with the silicon suspension in the amount 1 weight % in ratio to the cellulose- weight. The received spinning solution was filtered as in example I, subsequently at temperature 110° C forced through the holes in the spinning nozzle, placed 45 mm above the spinning bath, into the spinning bath as in Example I. The next step was as in Example I. The speed of fiber forming was 160 m/ min.

The received fibers were described as having tensile strength 38 cN/tex, elongation 12 % and fibrillization 3-4. Example IV.

Titan dioxide TiO₂ in the shape of nanomolecular powder, the grain diameter being 17 nm, was introduced into the cellulose solution in NMMO, prepared in the same conditions as in Example I, in the amount 1 weight % in ratio to the cellulose by weight, and the whole lot was exposed to mixing. The received spinning solution was filtered as in example I, subsequently at temperature 110° C forced through the holes in the spinning nozzle, placed 150 mm above the spinning bath, into the spinning bath at temperature 30°C containing 6% NMMO. The next step was as in Example I. The speed of fiber forming was 150 m/ min.

The received fibers were described as having tensile strength 36 cN/tex, elongation 10 % and fibrillization 3-4. Moreover they were described as having 50% greater ability to disperse UV radiation as compared to fibers received by all known methods. Example V.

Aqueous supension of zinc oxide ZnO with nanomolecular break up, the molecules diameter being 30 nm, was introduced into the cellulose solution in NMMO, prepared as in Example I, in such an amount that the ZnO content was 1 weight % in ratio to the cellulose weight, and the whole lot was mixed. The received spinning solution was filtered as in Example I, subsequently at temperature 110° C forced through the holes in the spinning nozzle, placed 60 mm above the spinning bath, into the spinning bath of 20° C, containing 4,5 % NMMO. The next step was as in Example I. The speed of fiber forming was 180 m/min.

The received fibers were described as having tensile strength 33 cN/tex, elongation 10%, fibrillization 3 and 37% greater ability to disperse UV radiation as compared to standard cellulose fibers. Example VI.

The spinning solution was prepared as in Example I, but at the same time, in the place of aqueous supension of silicon dioxide, aqueous solution of aluminium trioxide Al₂O₃ with nanomolecular break up, the molecules diameter being 37 nm, was added in such quantity that Al₂O₃ content was equal to 1,5 weight % in ratio to the cellulose by weight. The received spinning solution was filtered as in example I, subsequently at temperature 110°C forced through the holes in the spinning nozzle, placed 40 mm above the spinning bath, into the spinning bath of 20°C, containing 4% NMMO. The next step was as in Example I. The speed of fiber forming was 80 m/min.

The received fibers, circular in section, were described by the tensile strength 39 cN/tex, elongation 14 % and fibrillization 3. Example VII.

Aqueous supension of zinc oxide, titan _.dioxide and silicon dioxide (ZnO, Ti0₂, Si0₂) by component weight in ratio 1 : 1:1, with nanomolecular break up, the molecules diameter being 7-50 nm, was introduced into the cellulose solution in NMMO, prepared in the same conditions as in Example I, in such an amount that the oxides content was 3 weight % in ratio to the cellulose weight. The received spinning solution was filtered as in example I, subsequently at temperature 110°C forced through the holes in the spinning nozzle, placed 20 mm above the spinning bath, into the spinning bath of 20° C, containing 4% NMMO. The next step was as in Example I. The speed of fiber forming was 140 m/min.

The received fibers were described as having tensile strength 42 cN/tex, elongation 10%, fibrillization 3 and ability to disperse UV radiation 40% greater as compared to standard cellulose fibers. Example VIJI.

Solutions containing 12 weight parts of spruce cellulose (DP 840), 76 weight parts of NMMO, 12 weight parts of water, propyl_^ester. of gallic acid under the trade name Tenox in the amount 1 weight % in ratio to cellulose weight and a bactericide agent triclosan under the trade name Irgasan DP 300 in the shape of supramolecular powder, the molecules diameter being 137 nm, in the amount 0,5-5 weight % in ratio to the cellulose weight were prepared. The solutions were mixed at 117°C for 70 minutes under lowered pressure. From the originated spinning solutions after filtration fibers were formed by forcing the spinning solutions at temperature 115°C through the 18-hole spinning nozzle, the hole diameter being 0,4 mm and the duct length being 3,5 mm, with the speed 82 m/min into the coagulation bath containing water at temperature 20°C. The distance between the spinneret and the coagulation bath was 100 mm. The produced fibers were rinsed in water bath at temperature 80°C, subsequently they were dried.

Antibacterial activity of produced fibers towards Escherichia coli was estimated based on the Japanese standard JIS LI 902; 1998. It was stated that the fibers originating from the spinning solution already containing 0.5 weight % of antibacterial agent showed high both bactericidal and bacteriostatic activity. It was stated, moreover, that adding even 5 weight % of a bactericide agent into the spinning solution does not cause any significant changes in physico- mechanical parameters as compared to cellulose fibers produced without Irgasan.

Example IX.

The process of fiber making was repeated as in Example VIII, but instead of Irgasan silver iodide AgJ in the shape of nanomolecular powder, the grain diameter being up to 98 nm, was added to the spinning solution in the amount 0,2-5 weight % in ratio to the cellulose weight.

Antibacterial activity of produced fibers was estimated as in Example VIII. It was stated that the fibers received from the spinning solution already containing 0.5 weight % of antibacterial agent showed high both bactericidal and bacteriostatic activity. It was stated, moreover, that adding 5 weight % of AgJ to the spinning solution causes only slight reduction of fiber elongation at breaking, and of water retention, as compared to other fibers produced without AgJ. Example X.

The process of fiber making was repeated as in Example VIII, but, instead of Irgasan, Al₂O₃, doped with silver ion, under the trade name Biostat, in the shape of nanomolecular powder, the grain diameter being 57 nm, was added to the spinning solution in the amount 0,2-5 weight % in ratio to the cellulose weight. Antibacterial activity of produced fibers was estimated as in Example VIII. It was stated that the fibers originating from the spinning solution already containing 0.5 weight % of antibacterial agent showed high both bactericidal and bacteriostatic activity. It was stated, moreover, that adding 5 weight % of Biostat causes only slight change in physicomechanical parameters of fibers as compared to other fibers produced without Biostat. Example XI.

The process of fiber making was repeated as in Example VIII, but, instead of Irgasan, silver- zinc phosphate under the trade name Novaron, in the shape of supramolecular powder, the grain diameter being 132 nm, was added to the spinning solution in the amount 0,2-5 weight % in ratio to the cellulose weight.

Antibacterial activity of produced fibers was estimated as in Example VIII. It was stated that the fibers originating from the spinning solution already containing 0.5 weight % of antibacterial agent showed high bactericidal and bacteriostatic activity. The addition of even 5 weight % of Novaron caused insignificant physico-mechanical changes of the fibers as compared to other fibers produced without Novaron. Bactericidal properties of fibers made in Examples Vffl-XI were shown in tab.l, and physico-mechanical properties of these fibers, according to the amount of antibacterial agent added, in tab. 2. Table 1.

Table 2.

Example XII.

Carbon nanotubes in the shape of powder was introduced into the cellulose solution in^' NMMO, prepared as in Example I, in the amount 3 weight % in ratio to the cellulose by weight, and the whole lot was exposed to mixing. The received spinning solution was filtered, subsequently forced through the 18-hole spinning nozzle with the speed of 87m/min into the spinning bath at temperature 20°C The distance between the spinneret and the aqueous bath was 100 mm. The produced fibers were rinsed under stress in water bath at temperature 80° C, subsequently they were dried and conditioned. Subsequently mechanical and electrical properties of the fibers were measured. The received fibers were described as having tensile strength 36 cN/tex and elongation 10%. The fibers conducted the current, their resistance was 10 Ω*cm whereas the resistance of fibers not containing carbon nanotubes was 10¹⁰ Ω'cm

Example XIII.

The spinning solution was prepared as in Example XII, and at the same time carbon nanotubes, modified by metallic silver, in the shape of powder, were introduced into the cellulose solution in NMMO in the amount 3 weight % in ratio to the cellulose by weight,

Nanotubes were modified in such way that they were impregnated by aqueous solution of silver salt, subsequently the silver salts were reduced. Fibers were formed from the filtered spinning solution following Example XII.

It was stated that tensile strength of the received fibers was 36 cN/tex , elongation was 8% and their resistance rose to 10^"2 Ω'cm Example XIV.

The spinning solution was prepared as in Example I, but, at the same time, instead of silicon dioxide, thymol blue in the shape of a paste with supramolecular break-up, nibbed in the aqueous N-methylmorpholine-N-oxide solution, was introduced. The amount of introduced thymol blue was 0,5 weight % in ratio to the cellulose by weight. Fibers were formed from the filtered spinning solution following example XII. Tensile strength of the received fibers was 35 cN/tex , elongation was 10 %. It was stated, moreover, that the produced fibers changed their colour according to the pH of environment. An so, if dipped in an aqueous solution with the pH of 12, they turned blue, whereas dipped in an aqueous solution at the pH of 3, they turned yellow, what proved that the received fibers are the pH sensors. Example XV.

The spinning solution was prepared as in Example XIV, with such difference, that instead of thymol blue, phenolphthalein in the shape of nanomolecular powder, the molecules diameter being 96 nm, was introduced in the amount 0,3 weight % in ratio to the cellulose by weight. Fibers were formed from the filtered spinning solution following example XII.

Tensile strength of the received fibers was 32cN/tex , elongation was 10%. The produced fibers were white, and turned red, if dipped in an aqueous solution at the pH of 10, whereas if dipped in an aqueous solution at the pH of 8 they turned blue, what proved that the received fibers are the pH sensors. Example XVI.

The spinning solution was prepared as in Example XIV, with such, difference, that instead of thymol blue, thermochromic dye BT-31 in the shape of supramolecular powder, the molecules diameter being 173 rim, was introduced in the .amount 3 weight % in ratio to the cellulose by weight. Fibers were formed from the filtered spinning solution following example XII.

The produced fibers were pale blue, and turned white at the temperature 31° C. It proved that the received fibers are temperature sensors, Tensile strength of the received fibers was 35cN/tex , elongation was 12 %. Example XVII.

The spinning solution was prepared as in Example XIV, with such difference, that instead of thymol blue, thermochromic dye Bt-43 in the shape of nanomolecular powder, the molecules diameter being 85 nm, was introduced in the amount 2 weight % in ratio to the cellulose by weight. Fibers were formed from the filtered spinning solution following example XII.

The produced fibers were pale blue, and turned white at the temperature 43° C. In the temperature rising above 43° C they become colorless, and if the temperature was lowered below 43° C they became pale blue again. It proved that the received fibers had stable thermochromic properties. Tensile strength -of -the received fibers was 35cN/tex , elongation was 12 %.

Claims

Claims. Wc claim:

1) A method of making modified cellulose fibers from cellulose solutions in N- methylmorpholine-N-oxide consisting in mixing cellulose with aqueous N- methylmorpholinc-N-oxidc, evaporating of the originated spinning solution until 12- 20 weight % cellulose content and -less than 13 3 weight % water are left herein, filtration of the spinning solution, forcing of the spinning solution through the holes in the spinning nozzle into the airspace, from which it is led into water spinning bath, finally rinsing, drying and conditioning by means of adding modifying substances, claimed herein according to the invention that the modifying substances such as ceramic oxides, metal oxides or their mixtures, if necessary containing additional surfactants, carbon, if necessary modified with silver, bactericidal agents, acid-base indicators, thermochromic dyes with nano- or supra molecular break-up are added to the cellulose, to the solvent or to the spinning solution in the amount not bigger than 10 weight % in ratio to the cellulose solvent.

2) The method of claim 1 wherein ceramic oxides, advantageously silicon dioxide, metal oxides or their mixtures, are used in the shape of a powder or a suspension of the powder in water or aqueous solution of N-methylmorpholine-N-oxide.

3) The method of claim 1 wherein the carbon is in the shape of nanotubes.

4⁾ The method of claim 1 wherein thymol blue or phenolphthalein are prefarably used as acid based indicators.