COMPOSITION OF POLYACRYLONITRILE/LIGNIN BLEND AND USE THEREOF IN MELT SPINNING CARBON FIBRE PRECURSORS

Abstract

Described is a method of producing fibers by melting process in spinning extruders by using a composition containing polyacrylonitrile (PAN), lignin and plasticizers with high boiling point and dipolar moment, such as glycerine and glycerol carbonate. The use of thermal stabilizers also derived from halogenated glycerol, known as halodridines, and additives derived from the esterification of glycerin with fatty and phosphoric acids are also described. By removing the plasticizers and the soluble additives in polar solvents, such as water and alcohols, shortly after the spinning step, it is possible to produce fibers from PAN/lignin blend with characteristics similar to those produced by traditional wet spinning process, widely used in the production of carbon fiber. The lignin used may be that obtained by the Kraft Process. The glycerin used as a plasticizer can be derived from the production of biodiesel, which does not need to be purified by distillation process.

Claims

1. A polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber containing: a) minimum 45% of copolymer containing 70% or more of acrylonitrile monomer b) not more than 20% lignin c) not more than 35% combinations of other substances allowing melting and spinning of the blend to be classified into the following groups and having the following characteristics: I) plasticizers having a boiling point greater than 170 C., soluble in water and alcohols II) cyclization stabilizers having a boiling point greater than 170 C., soluble in water and alcohols, or derivatives of halogenated polymers III) lubricants having a boiling point greater than 170 C., soluble in water and alcohols IV) viscosity reducers having a boiling point greater than 170 C., soluble in water and alcohols

2. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 1, containing polyacrylonitrile copolymer having not more than 30% of comonomers, among which the vinyl acetate, methyl acrylate, methyl methacrylate, itaconic acid, acrylamide, acrylic acid, vinylidene chloride, styrene and vinyltoluene.

3. The polyacrylonitrile/lignin blend composition leading the production of carbon fiber precursor fiber, according to claim 1, containing plasticizers, substances having high boiling point, soluble in water and alcohols, such as glycerin, glycerol carbonate and combinations thereof.

4. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 1, containing as cyclization stabilizers, substances having high boiling point, soluble in water and alcohols, glycerine derivatives, such as 3-chloro-1,2-propanediol (-chlorohydrin), 3-fluoro-1,2-propanediol (-fluorohydrin), 3-bromo-1,2-propanediol (-bromohydrin), 1,3-dichloro-2-propanol, 1,3-difluoro-2-propanol, 1,3-dibromo-2-propanol and combinations thereof.

5. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 1, containing as cyclization stabilizers, substances having high boiling point, soluble in water and alcohols, such as inorganic acids, sulfuric acid and phosphoric acids, such as metaphosphoric acid, orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, phosphoglyceric acids and combinations thereof.

6. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 1, containing as cyclization stabilizers, halogenated polymers and copolymers, such as polyvinyl chloride (PVC), polyvinyl bromide, polyvinylidene chloride (PVDC) and polyvinylidene fluoride (PVDF).

7. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 4 containing not more than 5% cyclization stabilizers.

8. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 1, containing as extrusion lubricants, substances having high boiling point, soluble in water and alcohols, such as fatty acid mono and diesters derived from glycerin, mainly glyceryl monostearate, glyceryl distearate, glyceryl monooleate, glyceryl dioleate, glyceryl monolauratc, glyceryl monopalmitate, glyceryl dipalmitate, glyceryl monornyristate, and combinations thereof.

9. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 1, containing as viscosity reducers, substances having high boiling point, soluble in water and alcohols, such as ethylene carbonate, propylene carbonate, ethyleneglycol, diethyleneglycol, triethyleneglycol and combinations thereof.

10. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 1 using in the fiber deplasticizing process, the water and C1 to C3 alcohols as methanol, ethanol, propanol, isopropanol or mixtures thereof as solvents.

11. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 10, having a deplasticizing step which can be carried out continuously with the spinning process or discontinuously directly on the obtained coils.

12. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 1 producing meltblown polyacrylonitrile fibers which can be thermally stabilized and carbonized in conventional equipments, in the same way as the fibers produced by the wet spinning process.

13. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 1 producing meltblown polyacrylonitrile fibers which can have circular or several monolithic crossection, with diameters of 5 to 500 m and resistance >5 cN/tex.

14. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 5 containing not more than 5% cyclization stabilizers.

15. The polyacrylonitrile/lignin blend composition leading to the production of carbon fiber precursor fiber, according to claim 6 containing not more than 5% cyclization stabilizers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS OF THE INVENTION

[0020] Next, for a better understanding and comprehension of how the COMPOSITION OF POLYACRYLONITRILE/LIGNIN BLEND AND ITS USE IN MELTING SPINNING OF CARBON FIBER PRECURSOR is used herein, the accompanying illustrative figures are set forth.

[0021] FIG. 1Flowchart of the PAN/lignin blend process of manufacturing produced in melting spinning in extruder, according to this patent application.

[0022] FIG. 2Cross section by 3D X-ray microtomography of fibers of the 6% PAN-co-PVA with 25% of Kraft Lignin blend, being possible to observe the homogeneity of the lignin distribution in the polymer matrix.

[0023] FIG. 3DSC from a sample of a 6% PAN-co-PVA copolymer with 25% Kraft Lignin plasticized with 18% glycerin, 5% glycerol carbonate.

[0024] FIG. 4Infrared Spectroscopy (FTIR) with spectral comparison of samples of Kraft Lignin (superior), PAN-co-PS (10%) (medium), and 10% PAN-co-PS fiber with 20% Kraft Lignin blend and plasticized with 15% glycerin and 10% glycerol carbonate.

[0025] FIG. 5Infrared Spectroscopy (FTIR) with spectral comparison of samples of 10% PAN-co-PS fiber with 20% Kraft Lignin blend and plasticized with 15% glycerin and 10% glycerol carbonate before and after wash with water at 93 C.

[0026] FIG. 6A and B top, longitudinal sections of 10% PAN-co-PVA blend precursor fiber with 20% Kraft Lignin. C and D bottom, longitudinal and transverse sections of carbon fiber obtained by the carbonization at 1000 C. of 10% PAN-co-PVA precursor with 20% Kraft Lignin blend stabilized at 185 C. for 60 min. and oxidized at 280 C. for 30 min (SEM).

DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention describes the process for the production of thermoplastic polyacrylonitrile fiber for the manufacture of carbon fiber, comprising the following steps: (I) preparing a blend of copolymer of PAN, lignin, glycerin-derived plasticizers, stabilizers and additives in the form of powder or pellets; (II) transferring to an extruder; (III) subjecting step (I) to an extrusion process; (IV) obtaining the fibers (V) performing the deplasticizing of the fibers in hot baths; (VI) drying the fibers; (VII) performing the hot drawing of the fibers; (VIII) applying lubricating oil; (IX) obtaining coils of fibers.

[0028] According to FIG. 1, which shows the flowchart of the melting spinning process of the PAN/lignin blend of the present invention, the copolymer mixed with the plasticizers in powder form is fed into the hopper of the extruder. The extruder operates in a temperature range of 150 C. to 250 C. and melts the PAN/lignin blend, homogenization and transport to a gear pump which has the function of producing a high pressure of pumping the viscous fluid by the spinnerette. In the present invention circular spinnerette of 50 to 200 holes having diameters of 200 to 500 m have been used. Immediately after the exit from the spinnerette, the already cooled filaments are taken to several hot baths containing solvents capable of dissolving the plasticizers used and that do not attack the fibers. In the case of the use of glycerin and glycerol carbonate as plasticizers, water, ethanol, methanol, propanol, isopropanol and their aqueous solutions may be used.

[0029] Using water as the deplasticizing solvent, the working temperatures are between 70 C. and 93 C., and are carried out in 3 stages to minimize the entrainment of solubilised plasticizers from one tank to another. Tank 1 works at a temperature of 70 C. with a bath renewal rate of 15%/hour. The temperature of tank 2 is 80 C. and renewal rate of 5%/hour. For the complete removal of plasticizers from the fibers the maximum possible temperature of the water bath is used, which may be 90 C. to 95 C. in tank 3, depending on the local atmospheric pressure. In this third tank the recovery rate of the bath by evaporation and renewal is 5%/hour.

[0030] Using the 25% to 50% ethanol solution as the deplasticizing liquid the temperatures should be reduced by 10 C. and the temperature in the third bath should not exceed 80 C. Methanol can also be used, plus extra care should be used, since its vapors are very toxic.

[0031] Each tank of the deplasticizing bath of this invention was 15 cm high, 20 cm wide and 150 cm long, with a working capacity of 40 L. The heating was carried out with electrical resistance of 6000 W, allowing temperature adjustment with variation of +/3 C. The bath renovation was performed using Masterflex peristaltic pumps.

[0032] Soon after leaving the bath the fibers are fed to a quintet of heated rollers between 140 C. to 160 C. and a typical speed of 50 m/min for drying and then to another quintet of heated rollers to the same temperature with a typical speed of 200 m/min, where the drawing is carried out. In the already stretched fibers lubricant and antistatic spray (lubrication) is applied that is important for the production of coils with more uniform cables and with little breakage of filaments.

[0033] The fibers produced in accordance with this invention have a moisture content of <1% and a lubrication of 0.1% to 0.5%. The filaments have homogeneous distribution of the lignin in the polymer matrix, they do not present voids or holes and the diameters can vary according to the drawing rate of 10 to 50 microns, as can be seen in FIG. 2.

[0034] In the described process, the inventor solved the problem of PAN spinning by melting spinning process, performing its plasticization with the use of glycerin and its derivatives. According to FIG. 3, it is possible to clearly see by differential scanning calorimetry (DSC) analysis of PAN blends copolymerized with 6% polyvinyl acetate (PVA) with 25% kraft lignin and plasticized with 18% glycerol and 5% glycerol carbonate, the endothermic melting peak at 206 C., just before the exothermic peak related to polymer chain cyclization at 319 C. This means that the presence of lignin did not prevent the crosslinking of PAN, which is crucial for the thermal stabilization of the fibers.

[0035] For the plasticized PAN, its melting zone is at a temperature of approximately 100 C. below the chain's exothermic cyclization temperature, which allows the use of extruders for the production of fiber from the blends. The plasticization of PAN with high dipolar momentum substances such as water and glycerine derivatives causes the nitrile nitrogen dipole to be preferentially attracted by the hydrogen dipoles of the OH groups of these substances, retarding the formation of crosslinks with neighboring chains, allowing its melting.

[0036] Even with the heating of the PAN coated with glycerin, glycerol carbonate and mixtures thereof, its cyclization begins between 5 and 10 minutes after melting, observed by the color change of the molten polymer, from light yellow and fluid to dark brown and viscous. This residence time in the molten form is too short for its extruder processing. It has been found that if some halogenated or phosphorous additives were added in small concentrations together with the PAN plasticizers, the polymer may remain molten for up to 1 hour, sufficient time to allow its continuous processing. These additives are referred to herein as cyclization stabilizers and may be: high boiling inorganic acids such as phosphoric acid in the form of their esters with glycerin, such as phosphoglyceric acids, more commonly 2-phosphoglyceric acid and 3-phosphoglyceric acid; halohydrins derived from glycerin, such as 1-chloro-2,3-propanediol, 1,3-dichloro-2-propanol, 1-bromo-2,3-propanediol, 1,3-dibromo-2-propanol; and the chlorinated polymers polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC).

[0037] Other additives in this invention such as glycerin-derived fatty acid mono- and di-esters, more specifically glyceryl monostearate, glyceryl distearate, glyceryl monooleate, glyceryl dioleate, glyceryl monolaurate, glyceryl monopalmitate, glyceryl dipalmitate, glyceryl monomyristate and mixtures thereof are referred to as lubricants and the substances ethylene carbonate, propylene carbonate, ethyleneglycol, diethyleneglycol, triethyleneglycol and mixtures thereof are referred to as viscosity reducers.

[0038] The proportions used of plasticizers and additives in the present invention are no more than 35% and cyclization stabilizers no more than 5%.

[0039] At the same time, by selecting substances that are water soluble, the inventor solved the problem of the elimination of plasticizers from the fibers, which are undesired in the thermal stabilization step, by introducing a DEPLASTICIZING bath. The use of non-water soluble plasticizers would result in the use of other types of organic solvents to remove them from the fibers which would be a major economic and environmental disadvantage for the melting spinning process proposed in this invention. Thus, the fibers, when exiting the DEPLASTICIZING bath, are similar to those produced by wet spinning processes and can be stabilized, oxidized and carbonized in traditional carbon fiber furnaces.

[0040] FIG. 4 shows by Infrared Spectroscopy (FTIR) the spectral comparison of samples of Kraft Lignin (superior), PAN-co-PS (10%) (medium), and PAN-co-PS 10% with 20% Kraft Lignin blend fiber and plasticized with 15% glycerin and 10% glycerol carbonate. The band of 3400 cm.sup.1, which corresponds to the vibrational mode of stretch of hydrogen of group OH, is only observed in the blend due to the presence of glycerin added in the plasticization. The 2240 cm.sup.1 band is attributed to the nitrile group present in the PAN and the blend. The bands between 1200 and 1100 cm.sup.1 are attributed to the guaiacil and syringyl monomers found in Kraft Lignin, which can also be observed in the blend fibers.

[0041] FIG. 5 shows by Infrared Spectroscopy (FTIR) the spectral comparison of samples of 10% PAN-co-PS with 20% Kraft Lignin blend fiber and plasticized with 15% glycerin and 10% glycerol carbonate before and after washing with water at 93 C. in the DEPLASTICIZING bath. The efficiency of the deplasticization process is evidenced by the absence of the 3400 cm.sup.1 band in the washed blend fiber, referring to the OH group present in glycerol and glycerol carbonate, used as plasticizers. Therefore, the fibers after washing are no longer thermoplastic. The fibers from the DEPLASTICIZING bath are similar to those produced by wet process because they consist essentially of copolymers of PAN and lignin and, therefore, the stages of stabilization, oxidation and carbonization are also similar to those employed for traditional precursor fibers.

[0042] The fibers of the deplasticized PAN/Lignin blend when maintained isothermally between 180 to 190 C., are stabilized in time intervals'equivalent to the fibers produced by the wet process, but the coloring gradient easily observed during the process with the PAN fibers, which are initially white, turning to yellow, gold, brown and black at the end of the process, cannot be visualized with the fibers of the blend, since the lignin present gives them a dark initial coloration.

[0043] After thermal stabilization of these fibers, the oxidation and carbonization processes are performed as for any PAN precursor, producing carbon fibers with C content >90%, toughness >500 MPa and excellent mechanical properties for various applications.

[0044] The copolymers of the present invention have more than 70% units derived from acrylonitrile, copolymerized with one or more comonomers, and represented by acrylic units, such as:

##STR00003##

[0045] The Kraft Lignin used in this invention was purchased commercially from Sigma-Aldrich of Brazil, which the seller says was produced by the Lignoboost process. The molecular weight Mw was approximately 10 kDa, the ph of the 3% solution was 10.5, the sulfur content was 3.3% and the carbon content was 50.1%. Gravimetric analysis of the ash content at 750 C. resulted in 0.35%.

[0046] The glycerin mentioned in this invention was purified from biodiesel glycerin by chemical treatment and removal of water and methanol by vacuum heating without distillation. Due to the low content of glycerin, presence of unconverted fatty acids, lecithins, sodium hydroxide, sodium salts, and residual methanol, it is not possible to use them as a plasticizer of PAN without its purification. For this, residual glycerin sample supplied by Bioverde located in the city of Taubat (Brazil) with 85% content was submitted to the following process, based on the literature and described in Rev. Virtual Quim., 2014, 6 (6), p. 1564 to 1582: to 5.0 kg of crude glycerine heated to 70 C. was added, with stirring, 100 ml of 85% phosphoric acid. Under these conditions and after decantation, the fatty acids and lecithins are separated from the glycerin. This glycerin was filtered through activated charcoal bed for color removal and then passed in an ion exchange resin cartridge containing Amberlite IR 120 cation resin for removal of sodium salts. This glycerin was heated at 90 C. under vacuum for 1 hour to remove residual water and methanol. The final product had 97% purity content, 0.047% sodium ashes <20 mg/kg (ppm) and can be used as a plasticizer of the PAN/Lignin blend in this invention.

[0047] The other raw materials used herein, such as: glycerol carbonate was purchased from Huntsman and marketed under the trademark Jeffsol Glycerol Carbonate; PVC was purchased from Braskem and marketed under the trademark Norvic; fatty esters of glycerin were purchased from Polytechno Chemical Industries; ethylene glycol and diethyleneglycol were purchased from Oxiteno; the acrylonitrile, vinyl acetate, itaconic acid and acrylamide monomers were supplied by Radifibras; all other raw materials were purchased from Sigma-Aldrich do Brasil.

[0048] In order to further demonstrate the preferred embodiments, which are representative of, but not limited to, the experiments performed, the following application examples of the present invention will be presented; the acrylic copolymers described in that patent were produced by suspension polymerization employing acrylonitrile, comonomers, potassium persulfate (initiator, oxidizing agent), sodium bisulfite (activator, reducing agent), ammoniacal ferrous sulfate (redox catalyst) and tetrasodium EDTA (chelating agent), according to metolology described in the literature, Acrylic Fiber Technology and Applications, James C. Mason, 1995, p. 37 to 67.

EXAMPLE 01

[0049] Approximately 1500 g (54.7%) PAN copolymerized with 6% vinyl acetate with Mw 138,000, moisture content of 0.7% and particle size <20 m, was blended into a blender at 75 C. (18.2%) of Kraft Lignin, 525.0 g (19.2%) glycerol, 40.0 g (1.5%) 3-chloro-1,2-propanediol, 110.0 g (3.4%) of glyceryl monostearate, 50.0 g (1.8%) of 85% phosphoric acid and 16.0 g (0.6%) of ethylene glycol. After 20 minutes of homogenization the mixture was cooled for 1 hour. The obtained mass was sieved and the passing fraction less than 100 m was separated and fed into a 20 mm thread extruder at a speed of 60 rpm with 5 heating zones, the first area being 210 C., second, third and fourth Zones being 205 C. and the fifth zone comprising the gear pump and the spinnerette at 210 C. In this example the spinnerette had 90 holes with a diameter of 250 m. The fiber cable was deplasticized with hot water in three baths with respective temperatures of 70 C., 80 C. and 93 C., dried at a rate of 40 m/min at 130 C. in a quintet of rolls and drawn at 150 C. with a speed of 120 m/min in another quintet, with an lubricating bath (StantexFulcra Chemicals) and then coiled. The fibers obtained in this example were black, diameter 25 m, resistance of 11 cN/tex, moisture of 0.9% and lubrication. content of 0.3%.

[0050] A fiber strand of 90 filaments and 25% lignin content in the blend was stabilized at 180 C. for 60 minutes and heated at a rate of 10 C./min to 280 C. The temperature was maintained for 20 minutes. The black oxidized fiber was carbonized at 1000 C. under nitrogen for 12 minutes. The yield was 58.3% carbon, with a diameter of 20 m, toughness of 650 MPa and modulus of 75 GPa.

EXAMPLE 02

[0051] approximately 1500 g (51.3%) PAN copolymerized with 6.0% vinyl acetate with Mw 138,000, moisture content of 0.7% and particle size <20 m, was blended into a blender at 90 C. under stirring with 500 g (17.1%) Kraft Lignin, 586 g (20.0%) glycerin, 147 g (5.0%) glycerol carbonate, 29.0 g (1.0%) of 3-chloro-1,2-propanediol, 70.0 g (2.4%) of glyceryl monooleate, 65.0 g (2.2%) of 85% phosphoric acid and 28.0 g (1.0%) of ethyleneglycol. After 20 minutes of homogenization the mixture was cooled for 1 hour. The obtained mass was sieved and the passing fraction less than 100 m was separated and fed into a 20 mm thread extruder at a speed of 75 rpm with 5 heating zones, the first area being 205 C., second, third and fourth zone being 210 C. and the fifth zone comprising the gear pump and spinnerette 205 C. In this example the spinnerette had 50 holes with a diameter of 500 m. The fiber cable was deplasticized with hot water in three baths at respective temperatures of 70 C., 80 C. and 93 C., dried at a rate of 50 m/min at 130 C. in a quintet of rolls and drawn at 150 C. with a speed of 120 m/min in another quintet, with an lubrication bath (StantexPulcra Chemicals) and then coiled. The fibers obtained in this example were black, diameter 28 m, resistance 9 cN/tex, moisture 0.6% and lubrication content of 0.4%. The lignin content in this blend was 25%.

[0052] The 50-strand fiber strand was stabilized at 180 C. for 60 minutes and heated at a rate of 10 C./min to 275 C. The temperature was maintained for 20 minutes. The black oxidized fiber was carbonized at 1000 C. under nitrogen for 12 minutes. The yield was 58.5% carbon, with a diameter of 19 m, toughness of 690 MPa and a modulus of 82 GPa.

EXAMPLE 03

[0053] approximately 1600 g (55.7%) PAN copolymerized with 10% styrene with MW 158,000, moisture content of 0.50% and particle size <20 m, was blended in a blender at 90 C. under stirring with 400 g (13.9%) of Kraft Lignin, 500 g (17.4%) of glycerin, 150 g (5.2%) of glycerol carbonate, 71.0 g (2.5%) bromo-1,2-propanediol, 35.0 g (1.2%) of PVC NORVIC SP 700 HF' (Braskem), 80.0 g (2.8%) of 85% phosphoric acid and 35.0 g (1.2%) of diethyleneglycol.

[0054] After 20 minutes of homogenization the mixture was cooled for 1 hour. The obtained mass was sieved and the passing fraction less than 100 m was separated and fed in a 20 mm thread extruder and extruded at a speed of 60 rpm with 4 heating zones, the first zone being 195 C., the second and third being 200 C. and the fourth zone being 200 C. comprising a 3 mm diameter bore head. The extrudate was drawn up to 1.5 mm in diameter and cut into 2 mm long pellets.

[0055] These pellets were fed into a 20 mm thread. extruder and extruded at a speed of 80 rpm with 5 heating zones, the first zone being 205 C., the second, third, and fourth zone being 200 C. and the fifth zone comprising the gear pump and spinnerette at 205 C. In this example the spinnerette had 120 holes with a diameter of 250 m. The fiber strand was deplasticized with hot water in three baths at respective temperatures of 70 C., 80 C. and 93 C., dried at a rate of 40 m/min at 140 C. in a quintet of rolls and drawn at 150 C. with a velocity of 150 m/min in another quintet, with an lubricating bath (StantexPulcra Chemicals) and then coiled. The fibers obtained in this example were dark in color, diameter 22 m, resistance of 14 cN/tex, moisture of 0.6% and lubrication content of 0.26%. The lignin content in this blend was 20%.

[0056] The fiber strand of 120 filaments was stabilized at 190 C. for 60 minutes and heated at a rate of 10 C./min to 275 C. The temperature was maintained. for 10 minutes. The black oxidized fiber was carbonized at 1000 C. under nitrogen for 12 minutes. The yield was 57.5% carbon, with a diameter of 22 m, toughness of 780 MPa and modulus of 95 GPa.

EXAMPLE 04

[0057] approximately 1600 g (57.6%) copolymerized PAN with 2.4% acrylamide and 2.5% methyl acrylate with Mw 163,000, moisture content of 0.70% and particle size <20 m was blended in a blender at 90 C. under stirring with 400 g (14.4%) Kraft Lignin, 300 g (10.8%) glycerin, 300 g (10.8%) glycerol carbonate, 40.0 g (1.4%) of 60% mixture of glyceryl monostearate and 40% of glyceryl distearate, 32.0 g (1.2%) of PVC NORVIC SP 700 HF, 52.0 g (1.9%) of mixture containing 2-phosphoglyceric acids and 3-phosphoglyceric acid with 25% phosphoric acid and 55.0 g (2.0%) of propylene carbonate.

[0058] After 20 minutes of homogenization, the mixture was cooled for 1 hour. The obtained mass was sieved and the passing fraction less than 100 m was separated and fed in a 20 mm thread extruder and extruded at a speed of 50 rpm with 4 heating zones, the first zone being 205 C., the second and third being 200 C. and the fourth zone being 205 C. comprising a 3 mm diameter bore head. The extrudate was drawn to 2.0 mm in diameter and cut into 2 mm long pellets.

[0059] These pellets were fed into a 20 mm thread extruder and extruded at a speed of 60 rpm, with 5 heating zones, the first zone being 205 C., the second, third and fourth zones being 200 C. and fifth zone comprising the gear pump and the spinnerette with 210 C. In this example the spinnerette had 50 holes with a diameter of 500 m. The fiber cable was deplasticized with hot water in three baths with respective temperatures of 70 C., 80 C. and 93 C., dried at a rate of 65 m/min at 140 C. in a quintet of rolls and drawn at 150 C. C. with a speed of 130 m/min in another quintet, with an lubricating bath (StantexPulcra Chemicals) and then coiled. The fibers obtained in this example were black, diameter 35 m, strength 9 cN/tex, moisture 0.4% and lubricating content 0.29%. The lignin. content in this blend was 20%.

[0060] The 50-filament fiber cable was stabilized at 180 C. for 60 minutes and heated at a rate of 10 C./min to 275 C. The temperature was maintained for 20 minutes. The black oxidized fiber was carbonized at 1000 C. under nitrogen for 12 minutes. The yield was 58.7% carbon, with a diameter of 24 m, toughness of 678 MPa and modulus of 67 GPa.

EXAMPLE 05

[0061] approximately 1440 g (47.3%) PAN copolymerized with. 4.6% methyl acrylate and 6.0% styrene with Mw 121,000, moisture content of 0.50% and particle size <20 m was blended in a blender at 90 C. under stirring with 560 g (18.4%) Kraft Lignin, 550 g (18.1%) glycerin, 280 g (9.2%) glycerol carbonate, 22.0 g (0.7%) of 1,3-dichloro-2-propanol, 73.0 g (2.4%) of 60% mixture of glyceryl monostearate and 40% glyceryl distearate, 60.0 g (2.0%) of 85% phosphoric acid and 60.0 g (2.0%) of propylene carbonate.

[0062] After 30 minutes of homogenization the mixture was cooled for 1 hour. The obtained mass was sieved and the passing fraction smaller than 100 m was separated and fed in a 20 mm thread extruder and extruded at a speed of 60 rpm with 4 heating zones, the first zone being 195 C., the second zone and third being 200 C. and the fourth zone being 198 C. comprising a 3 mm diameter bore head. The extrudate was drawn to 2.0 mm in diameter and cut into 2 mm long pellets.

[0063] These pellets were fed into a 20 mm thread extruder and extruded at a speed of 60 rpm with 5 heating zones, the first zone being 195 C., the second, third and fourth zone being 198 C. and fifth zone comprising the gear pump and the spinnerette with 198 C. In this example the spinnerette had 150 holes with a diameter of 250 m. The fiber cable was deplasticized with hot water in three baths with respective temperatures of 70 C., 80 C. and 93 C., dried at a rate of 55 m/min at 145 C. in a quintet of rolls and drawn at 150 C. with a velocity of 160 m/min in another quintet, with an lubricating bath (StantexFulcra Chemicals) and then coiled. The fibers obtained in this example were black with a diameter of 23 m, resistance of cN/tex, moisture of 0.5% and lubricating content of 0.22%. The lignin content in this blend was 28%.

[0064] The fiber strand with 150 filaments was stabilized at 180 C. for 60 minutes and heated at a rate of 10 C./min to 275 C. The temperature was maintained for 20 minutes. The black oxidized fiber was carbonized at 1000 C. under nitrogen for 12 minutes. The yield was 57.8% carbon, with a diameter of 17 m, toughness of 635 GPa and a modulus of 82 GPa.

[0065] For the advantages it offers, and also, because it has truly innovative characteristics that meet all the requirements of novelty and originality in the genre, the present COMPOSITION OF POLYACRYLONITRILE/LIGNIN BLEND AND ITS USE IN MELTING SPINNING OF CARBON FIBER PRECURSOR, meets the conditions necessary and sufficient to deserve the patent of invention.