RU2431004C2 - Method of producing multicomponent cellulose fibre - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: first, a microscopically homogenised solution is obtained by dispersing 75-25 vol. % cellulose and 25-75 vol. % of at least another fibre-forming polymer in a water-containing ionic liquid while adding stabilisers and completely removing water using shear, temperature and vacuum. The solution is formed through at least one die hole into a fibre or bundle of fibres, which is directed through a conditioned gap while drawing in order to deposit directed jets of the solution via treatment with a temperature-controlled solution of a precipitation agent for cellulose and another fibre-forming polymer, mixed with an ionic liquid so that spinodal layering takes place. The directed jets of the solution are removed from the settling bath and undergo subsequent treatment.

EFFECT: obtained fibre has low swelling capacity and high resistance to wet wearing.

10 cl, 6 tbl, 4 ex

Description

The invention relates to a method for producing cellulosic multicomponent fibers with reduced swelling and increased resistance to wet abrasion.

State of the art

Viscose fibers due to the inclusion of the second component can undergo a significant increase in swelling, manifested in the possibility of water retention (WRV) (WBW) (M. Einzmann et al .; Lenzinger Berichte 84 (2005) 42-49). No examples of IWV reduction are known.

The addition of a second polymer to a solution of cellulose in N-methylmorpholine-N-oxide monohydrate (NMMO) promotes the production of lyocell fibers with discrete introduction of the second component into the pores of the system, which have increased swelling regardless of whether the second component has hydrophilic or hydrophobic properties (M Einzmann et al .; Lenzinger Berichte 84 (2005) 42-49; F. Meister et al .; Lenzinger Berichte 78 (1998) 59-64; Ch. Michels; Abschlussbericht zum BMW A-Projekt “Modelluntersuchungen zum Lyocell-Prozess”, Reg. No. 1077/03 (2005) 13-19).

International application WO 98/09009 describes the addition of linear synthetic polymers, for example NP polyethylene, to a solution of cellulose in NMMO. Although the added polymer is hydrophobic and, when dispersed, exists in a molten form (working temperatures are higher than the melting temperature of the added polymer), in this case, islands of the matrix structure with constant or increased swelling also form. Studies of lyocell fibers or modified lyocell fibers have shown that there is a double logarithmic relationship between their HLW and wet abrasion resistance (NSB) (Ch. Michels; Abschlussbericht zum BMWA-Projekt “Modelluntersuchungen zum Lyocell-Prozess”, Reg.Nr. 1077/03 (2005) 21).

Only with the help of the subsequent preparation of cellulose fiber derivatives with hydrophobic substituents can a swelling reduction and an increase in the media be achieved.

Methods for producing lyocell fibers from ionic liquids are described in German patent DE 10 2004 031 025 B3, wherein these cellulosic fibers have a swellability comparable to lyocell fibers made by a process in NMMO.

International application WO 2005/098546 A2 describes the preparation of mixtures of at least two different polymers or copolymers with at least one ionic liquid. In this case, the polymers are separately dissolved directly in almost anhydrous ionic liquids, the polymer solutions are mixed and irrigation films are obtained from the polymer mixture by precipitation with aqueous media and characterize them. Obtaining fibers is not described, nor do they provide evidence of swelling of the obtained polymer mixtures.

Object of the invention

The objective of the invention is to provide a simple method for producing cellulosic multicomponent fibers with reduced swelling and increased resistance to wet abrasion.

This problem in the method according to the invention is solved in that 75-25 volume% of cellulose and 25-75 volume% of at least one other fiber-forming polymer component are dispersed in a water-containing ionic liquid when stabilizers are added, water is removed as much as possible by shear, heat supply and vacuum, the obtained microscopically homogeneous solution is formed through at least one die into a fiber / fiber bundle, it is directed through an air-conditioned gap during drawing, and an oriented stream of solution is deposited by treating with a thermostatic solution, which is mixed with an ionic liquid, which is a precipitant for cellulose and another fiber-forming polymer component, with spinodal separation, oriented jets of the solution are removed from the precipitation bath and then subjected to further processing.

It was unexpectedly found that ionic liquids that contain cellulose and a specific fiber-forming polymer, such as polyacrylonitrile (PAN) or a polyacrylonitrile copolymer, in a known concentration range, are able to form not a matrix-island structure, but a matrix-matrix structure, etc. e. two separate continuous phases that are retained during spinodal separation during deposition. After separation of the cellulose using Kuoxam (Schweizer's reagent), the fiber structure of the PAN remains (comparative figure 1). The obvious consequence is that the swelling is clearly reduced, but the media is increasing. As can be seen from example 2 (figure 2), here also remains a double logarithmic relationship, which in the region of 0-75 vol.% PAN obeys the equation

ln media = 39.772-8.686 (ln HLW)

with R = 0.998. From the data on the tensile strength of dry and wet (fiber) depending on the composition in vol.% (Figure 3), we can conclude that when mixing 50 vol.% PAN phase inversion occurs. With a proportion of> 50% vol. Cellulose, the ratio of σ _dry / σ _wet ≥1, with a proportion> 50% vol. PAN σ _dry / σ _wet ≤1.

Further, it turned out to be favorable when the second polymer alone forms a low-viscosity solution with an ionic liquid and is therefore easily dispersible. The viscosity ratio at zero shear of the cellulose / second polymer system should clearly lie above 1, preferably above 10.

A suitable cellulose component was fiber from wood, cotton and other annual plants obtained by the sulfite, sulfate or prehydrolysis sulfate method. Methods for bleaching cellulose are of subordinate importance.

As the second polymer, polyacrylonitrile (PAN) and copolymers of polyacrylonitrile, for example, with 6 wt.% Methyl acrylic acid ester, turned out to be optimal. The second component may be in the form of a powder or fiber (Dolanit ^® , Dolan ^® , Dralon ^® , Orlon ^® , volpril fiber, etc.) and preferably should have hydrophobic properties.

Imidazole derivatives such as 1-butyl-3-methylimidazole chloride (BMIMCl), 1-ethyl-3-methylimidazole chloride (EMIMCl), 1-butyl-3-methylimidazole acetate (BMIMAc), 1-ethyl-3-methylimide were tested as ionic liquids. (EMIMAc).

The stabilization of polymer solutions occurs by controlling the concentration of hydrogen ions (pH value) in them with a non-volatile base, for example sodium hydroxide or polyethyleneimine, and, if necessary, the addition of propyl gallate or similar stabilizers, such as tannin, p-phenylenediamine, quinone.

Suitable precipitants are water and / or water-miscible alcohols, which may contain up to 50% of ionic liquids used as a solvent.

The invention can be illustrated using the following examples.

EXAMPLES

Example 1

The preparation of solutions of cellulose, the second polymer in ionic liquids, and their characterization and spinning of fibers occurred according to the following general method.

The required amount of cellulose and fibers of the second polymer was mixed according to the given mixture ratio, in the bath module (ratio of solutions) (Flottenverhältnis) 1:20 in water, they were crushed using an Ultra-Turrax device and dehydrated by pressing to about 35 wt.%. The required amount of squeezed polymer mixture, corresponding to the desired solid content of the polymer solution, was introduced into an ionic liquid containing 20 wt.% Water and stabilizers, and dispersed, and by adding 0.1 molar aqueous NaOH solution, a pH value> 8 of the aqueous suspension was established.

If the second polymer was in the form of a powder, the cellulose was separately milled in water and squeezed. The powdered second polymer was dispersed directly in an ionic liquid containing 30 wt.% Water and stabilizers, then squeezed cellulose was added and dispersed, and a pH of> 8 aqueous suspension was adjusted by adding 0.1 molar aqueous NaOH.

After placing the suspension in a vertical mixer with a strong shear, a slowly increasing temperature from 90 to 130 ° C and a reduced pressure from 850 to 5 mbar with complete removal of water, a homogeneous polymer solution was obtained. The dissolution time in all cases was 90 minutes. Solutions were evaluated by their microphotographs in polarized light and rheologically characterized. The results are shown in table 1.

Table 1 No. The second polymer is the polymer ratio of cellulose / second polymer (wt.%) Solvent Solids content (%) η ₀ ^{85 ° C}
(Pass) 1.1 Homopolymer PAN - 80/20 BMIMCl 13.9 41760 1.2 Copolymer PAN - 80/20 BMIMCl 14.1 39800 1.3 Homopolymer PAN - 80/20 BMIMAc PAN does not dissolve 1.4 Homopolymer PAN - 60/40 Emimcl 20.3 28167 1.5 Cellulose-2,5-acetate - 80/20 BMIMCl 13.1 33460 1.6 Chitin - 80/20 BMIMCl Chitin does not dissolve 1.7 Chitin - 80/20 BMIMAc Chitin does not dissolve 1.8 Chitosan - 80/20 BMIMCl Chitosan does not dissolve 1.9 Chitosan - 80/20 BMIMAc Chitosan does not dissolve 1.10 Polyamide 1465 - 80/20 BMIMCl 14.3 39380 1.11 PLA - 80/20 BMIMCl PLA does not dissolve 1.12 PLA - 80/20 BMIMAc 13.8 325 1.13 PLA - 80/20 EMIMAc 14.0 650 1.14 Wool - 80/20 BMIMCl 12.9 8413 1.15 PMMA - 80/20 BMIMCl PMMA does not dissolve 1.16 PMMA - 60/40 BMIMAc 16.8 21540 ¹ 1.17 PMMA - 90/10 BMIMAc 11.0 3606 ¹ - Viscosity at zero shear at 110 ° C
BMIMCl: 1-butyl-3-methylimidazole chloride
EMIMCl: 1-ethyl-3-methylimidazole chloride
BMIMAc: 1-butyl-3-methylimidazole acetate
EMIMAc: 1-ethyl-3-methylimidazole acetate
PAN homopolymer: Dolanit 10, polyacrylonitrile fiber
PAN copolymer: copolymer with 6% methyl ester of acrylic acid
PLA: polylactide
PMMA: polymethyl methacrylate

Spinning of polymer solutions was carried out according to the methods described below. The required amount of spinning solution (mass flow) was supplied with a mass temperature of 85 ° C through a piston spinning device to a spinning bag, filtered, heated in a heat exchanger to a spinning temperature of Θ _pr , subjected to relaxation in the collecting chamber and squeezed out using 30 nozzles with 30 spinning capillaries the ratio L / D _a 1 and the output diameter D _a 90 μm. The jets of the solution passed through an air-conditioned gap of length a and were additionally blown with air with a temperature of 25 ° C and humidity and an amount of air in accordance with Table 2. An oriented set of threads (a family of parallel threads extending at a certain distance in one plane) was carried out while polymer mesh into a precipitation bath with a temperature of 20 ° C, was isolated from the coagulation bath at a speed of drawing v _a = 30 m / min at an angle β≈40 ° C, pulled through the biscuits (Galetten) and subjected to discrete freedoms oh from internal stresses further processed by washing and drying. The spinning conditions for some of the polymer blends described in table 1 are shown in table 2 under the same numbers.

table 2
Spinning conditions No. Temperature strand. masses
Θ _ol (° C) Air gap a
(mm) Air quantity
(l / min) Air humidity
(g / m ³ ) Spinning Characteristic 1.1 103.5 90 35 3.0 1.7 / 1.3 dtex very good 1.2 102.0 80 35 3.8 1.7 / 1.3 dtex very good 1.4 109,4 110 without 9.6 1.7 dtex is very good 1.5 100.0 80 70 3.2 1.7 dtex spins 1.10 104.1 90 fifty 3.0 1.7 / 1.3 dtex very good 1.14 83.9 fifty 60 3.2 1.7 dtex spins 1.16 100-130 Not spinning 1.17 88.8 70 70 3.0 1.7 dtex spins

Example 2

Eucalyptus fiber (Kuoxam-DP indicator: 556) and fiber from a polyacrylonitrile homopolymer (DOLANIT 10) were mixed in different mix ratios, in a 1:20 bath module, they were crushed in water using an Ultra-Turrax device and dehydrated by squeezing to about 35 wt. .%. The required amount of squeezed polymer mixture corresponding to the desired solid content of the polymer solution was added to BMIMCl containing 20 wt.% Water and 0.03 wt.% Propyl ester of gallic acid, and dispersed to obtain a homogeneous polymer solution in accordance with the options described in example 2. The results are shown in table 3.

Various micrographs after receiving the solutions showed homogeneous solutions that did not contain any parts of the broken fibers from the residues of cellulose or PAN. However, with an increase in PAN content, micrographs showed the emerging Tyndall effect. Solutions were rheologically characterized before spinning.

The determination of fiber-DP was similar to the determination of pure cellulose fiber, taking into account the weight of the cellulose according to the used ratio of the mixture. Cellulose was selectively isolated from the fiber using Kuoxam, while polyacrylonitrile (PAN) was insoluble in Kuoxam. In this case, after the selective dissolution process in Kuoxam, the fiber structure of the remaining PAN was preserved (see Fig. 1).

Table 3
Cellulose solutions - PAN, different mixture ratios. No. Polymer ratio
cellulose / PAN (wt.%) The solids content in the polymer solution (%) η ₀ ^{85 ° C}
(Pass) Fiber DP 2.1 100/0 (comparative example) 11.2 14530 509 2.2 90/10 12.1 14770 484 2.3 80/20 13.9 41760 465 2.4 70/30 15,2 29860 441 2.5 65/35 16.5 45574 447 2.6 60/40 17,2 39307 474 2.7 50/50 19,2 29500 430

Cellulosic multicomponent fibers were spun from polymer solutions using a piston spinning device using a dry / wet spinning process in accordance with the methods described in example 1. The spinning conditions and data on the fiber of the obtained fibers are given below and in table 4.

General spinning conditions:

Nozzle mouth diameter: 90 μm

Number of capillaries nozzle: 30

Draw speed: 30 m / min

The temperature of the precipitation bath: 20 ° C

Table 4
Spinning conditions and fiber data Example 2.1
(cf.) 2.2 2.3 2.4 2.5 2.6 2.7 Pulp / PAN Ratio 100/0 90/10 80/20 70/30 65/35 60/40 50/50 Wt% 100/0 87.4 / 75.4 / 64.1 / 58.7 / 53.5 / 43.4 / About.% 14.6 24.6 35.9 41.3 46.5 56.6 Spinning conditions: Mass flow (g / min and nozzle) 1.25 1,11 0.98 0.89 0.82 0.78 0.73 Spinning temperature Θ _ol (° C) 93.5 90.0 103.5 104.7 103.3 103.9 114.2 Air gap a (mm) 80 80 90 90 90 125 90 Amount of air (l / min) 60 35 35 twenty 25 twenty 5 Humidity (g / m ³ ) 2.7 2.2 3.0 5,0 4.3 2.6 3 Fiber Properties: Tonine (linear density) (dtex) 1.73 1.66 1.68 1,69 1,67 1.73 1.72 Tear Strength, Cond. (cN / tex) 50.3 44.6 35.1 30,4 27.3 23.9 19,4 Tensile strength, wet. (cN / tex) 43.7 37.5 34.2 28.0 27.7 26.7 19.5 Extension, cond. (%) 11.7 10.6 9.2 15,5 10.7 10.3 12.9 Elongation, wet (%) 12.8 12,2 12.9 18.2 19.3 16.9 28.9 Loop breaking force
(cN / tex) 22.2 19.5 18.6 16.6 15,5 11.0 13.1 Wet abrasion ¹ (rpm) 28 36 59 114 221 618 4466 The ability to retain water (%) 65.9 64,4 61.3 57.3 53,2 45.3 37.5 Affinity for dye ² (mg / g) fifty 54 54 54 52 ¹ A method for determining wet abrasion resistance is described in K.-P. Mieck, H. Langner; A. Nechwatal; Lenzinger Berichte 74 (1994) 61-68.
² Dye affinity was determined in a 6% Direct Red 81 dye solution (reaction conditions: 3 hours at 80 ° C, 14.2 g / l sodium sulfate). Cellulose-PAN fiber exhibits a slightly higher affinity for dye compared to pure cellulose fiber, while the used PAN fiber Dolanit 10 has no affinity for this dye (affinity for dye: 0 mg / g).

The double logarithmic relationship between NSB (media) and WRV (WBV), found for lyocell fibers from cellulose solutions / second component in NMMO, was confirmed using this example for lyocell fibers from cellulose / PAN in ionic liquids in an exceptional way (comparative figure 2) .

The image of the dependence of the tensile strength of dry and wet (method) on the composition in volume% when using these fibers for a mixture of 24.7 vol.% Cellulose / 75.5 vol.% PAN (example 4, table 4 is not contained) in FIG. 3 shows a very distinct phase inversion at a volume ratio of 50 to 50.

Example 3

Cellulose / PAN mass ratio (60:40)

Cellulose cotton lint (Kuoxam-DP indicator: 454) and PAN fiber (Dolanit 10) in a 1:20 bath module were pulverized in water using an Ultra-Turrax device to separate fibers and squeezed to a solids content of 35% by weight. 174 g of the pressed fiber mixture was added to 341.6 g of 1-ethyl-3-methylimidazole chloride (EMIMCl) containing 30 wt.% Water and 0.2 g of gallic acid propyl ester was dispersed to obtain a homogeneous suspension in which, using 0 , 1 molar aqueous solution of sodium hydroxide was adjusted to pH> 8. After placing the suspension in a vertical mixer with a strong shear, a slowly increasing temperature from 90 to 125 ° C and a reduced pressure from 850 to 5 mbar, a homogeneous polymer solution was obtained by distillation of water. The dissolution time was 90 minutes.

The analytical characteristics of the polymer solution are presented by the following data:

Solids content: 20.3%

Viscosity at zero shear: (85 ° C): 28167 Pa · s

Fiber was spun from polymer solutions through a dry / wet spinning process. The spinning conditions and fiber size are shown in the following table 5.

Table 5
Spinning conditions and fiber data Example 3 Spinning conditions: Mass flow (g / min and nozzle) 0.73 Spinning temperature Θ _ol (° C) 109,4 Air gap a (mm) 110 Amount of air (l / min) no Humidity (g / m ³ ) 9.6 Fiber Properties: Tonina (Dtex) 1.84 Tear Strength, Cond. (cN / tex) 25,4 Tensile strength, wet. (cN / tex) 21.8 Extension, cond. (%) 34.3 Elongation, wet (%) 39.3 Loop breaking force (cN / tex) 21.7 Wet abrasion ¹ (rpm) 250 Fiber DP 422

Example 4

Cellulose / PAN mass ratio (30:70)

12.0 g of eucalyptus fiber (dry matter content: 95%, Kuoxam-DP indicator: 892) and 26.8 g PAN fiber (Dolanit 10, dry matter content 99.25%) together in the 1:20 bath module water was crushed by means of Ultra-Turrax to individual fibers and squeezed to a solids fraction of 25%. The pressed fiber mixture was added to 265 g of 1-butyl-3-methylimidazole chloride (BMIMCl) containing 20 wt.% Water and 0.1 g of gallic acid propyl ester and dispersed to obtain a homogeneous suspension in which the pH was adjusted using a non-volatile base > 8. After placing the suspension in a vertical mixer with a strong shear, a slowly increasing temperature from 90 to 135 ° C and a reduced pressure from 850 to 3 mbar, a homogeneous polymer solution was obtained by distillation of water. The dissolution time was 90 minutes.

The analytical characteristics of the polymer solution are presented by the following data:

Solids content: 15.2%

Viscosity at zero shear: (95 ° C): 927 Pa · s

Fiber was spun from polymer solutions through a dry / wet spinning process. Spinning conditions and fiber data are shown in the following table 6.

Table 6
Spinning conditions and fiber data Example four Spinning conditions: Mass flow (g / min and nozzle) 0.91 Spinning temperature Θ _ol (° C) 98.8 Air gap a (mm) 90 Amount of air (l / min) 17 Humidity (g / m ³ ) 7.8 Fiber Properties: Tonina (Dtex) 1.82 Tear Strength, Cond. (cN / tex) 12,2 Tensile strength, wet. (cN / tex) 12.7 Extension, cond. (%) 13 Elongation, wet (%) 32 Loop breaking force (cN / tex) 9.2 Wet abrasion (rpm) > 10,000 ¹ The ability to retain water (%) 17.6 ¹ With the wet abrasion determination method, measurements after 10,000 rpm are stopped, so large values cannot be determined.

Claims (10)

1. The method of producing cellulosic multicomponent fibers with reduced swelling from ionic liquids, characterized in that 75-25% vol. Cellulose and 25-75% vol., At least one other fiber-forming polymer component is dispersed in a water-containing ionic liquid with the addition of stabilizers completely remove the water by shearing, applying heat and vacuum, the microscopically obtained homogeneous solution is formed through at least one spinneret into a fiber / fiber bundle, directing it through an air-conditioned gap pulling precipitated oriented solution jets by treatment thermostated solution which is admixed with the ionic liquid and which is a nonsolvent for cellulose and other fiber-forming polymer component, so that spinodal bundle was removed oriented solution jets from the coagulation bath and then subjected to subsequent processing. 2. The method of producing cellulosic multicomponent fibers according to claim 1, characterized in that cellulose component is used fiber with the indicator "Kuoksam-DP" in the region of 300-2000, obtained from wood, cotton lint or other annual plants on sulphite, sulphate / prehydrolysis sulfate method. 3. The method of producing cellulosic multicomponent fibers according to claim 1, characterized in that polyacrylonitrile is used as another fiber-forming component. 4. The method of producing cellulosic multicomponent fibers according to claim 1, characterized in that polyacrylonitrile copolymers are used as another fiber-forming component. 5. The method of producing cellulosic multicomponent fibers according to claim 1, characterized in that the ratio of viscosities at zero shear of cellulose and second polymer solutions in an ionic liquid has a value exclusively above 1. 6. The method of producing cellulosic multicomponent fibers according to claim 1, characterized in that 1-butyl-3-methylimidazole chloride (BMIMCl) and / or 1-ethyl-3-methylimidazole chloride (EMIMCl) and / or 1 are used as ionic liquids -butyl-3-methylimidazole acetate (BMIMAc), and / or 1-ethyl-3-methylimidazole acetate (EMIMAc). 7. The method of producing cellulosic multicomponent fibers according to claim 1, characterized in that non-volatile bases are used as stabilizers individually or in combination with propyl gallate, tannin, p-phenylenediamine or quinone. 8. The method of producing cellulosic multicomponent fibers according to claim 1, characterized in that alkali metal hydroxides or polyethyleneimine are used as non-volatile bases. 9. The method of producing cellulosic multicomponent fibers according to claim 1, characterized in that water and / or water-miscible alcohols, which may contain up to 50% of the ionic liquid used as a solvent, are used as precipitants. 10. Cellulosic multicomponent fiber with reduced swelling obtained by the method according to one of claims 1 to 9.

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