CN117535815A - Method for improving drawability of dry-jet wet-spun carbon fiber precursor - Google Patents
Method for improving drawability of dry-jet wet-spun carbon fiber precursor Download PDFInfo
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- CN117535815A CN117535815A CN202311682376.0A CN202311682376A CN117535815A CN 117535815 A CN117535815 A CN 117535815A CN 202311682376 A CN202311682376 A CN 202311682376A CN 117535815 A CN117535815 A CN 117535815A
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- 239000002243 precursor Substances 0.000 title claims abstract description 32
- 238000000034 method Methods 0.000 title claims abstract description 22
- 229920000049 Carbon (fiber) Polymers 0.000 title claims abstract description 13
- 239000004917 carbon fiber Substances 0.000 title claims abstract description 13
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 9
- 238000009987 spinning Methods 0.000 claims abstract description 37
- 238000001035 drying Methods 0.000 claims abstract description 33
- 239000000178 monomer Substances 0.000 claims abstract description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 27
- 230000015271 coagulation Effects 0.000 claims abstract description 20
- 238000005345 coagulation Methods 0.000 claims abstract description 20
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical compound N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 claims abstract description 17
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 claims abstract description 17
- 238000005406 washing Methods 0.000 claims abstract description 17
- 239000007787 solid Substances 0.000 claims abstract description 16
- 230000007935 neutral effect Effects 0.000 claims abstract description 14
- 230000002378 acidificating effect Effects 0.000 claims abstract description 11
- 238000009998 heat setting Methods 0.000 claims abstract description 9
- 239000003999 initiator Substances 0.000 claims abstract description 9
- 229920006395 saturated elastomer Polymers 0.000 claims description 40
- 239000000243 solution Substances 0.000 claims description 20
- 230000001112 coagulating effect Effects 0.000 claims description 17
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 16
- 230000008569 process Effects 0.000 claims description 9
- JAHNSTQSQJOJLO-UHFFFAOYSA-N 2-(3-fluorophenyl)-1h-imidazole Chemical compound FC1=CC=CC(C=2NC=CN=2)=C1 JAHNSTQSQJOJLO-UHFFFAOYSA-N 0.000 claims description 7
- LVHBHZANLOWSRM-UHFFFAOYSA-N methylenebutanedioic acid Natural products OC(=O)CC(=C)C(O)=O LVHBHZANLOWSRM-UHFFFAOYSA-N 0.000 claims description 7
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 claims description 6
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 6
- RUMACXVDVNRZJZ-UHFFFAOYSA-N 2-methylpropyl 2-methylprop-2-enoate Chemical group CC(C)COC(=O)C(C)=C RUMACXVDVNRZJZ-UHFFFAOYSA-N 0.000 claims description 4
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 4
- 239000011550 stock solution Substances 0.000 claims description 4
- FQPSGWSUVKBHSU-UHFFFAOYSA-N methacrylamide Chemical compound CC(=C)C(N)=O FQPSGWSUVKBHSU-UHFFFAOYSA-N 0.000 claims description 3
- 239000002253 acid Substances 0.000 abstract description 3
- 239000010410 layer Substances 0.000 description 21
- 229920002239 polyacrylonitrile Polymers 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 7
- 229920001577 copolymer Polymers 0.000 description 7
- 229920006240 drawn fiber Polymers 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 238000004886 process control Methods 0.000 description 6
- 230000002040 relaxant effect Effects 0.000 description 6
- 238000007493 shaping process Methods 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 238000004804 winding Methods 0.000 description 6
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 2
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 229920000297 Rayon Polymers 0.000 description 1
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 1
- KVNRLNFWIYMESJ-UHFFFAOYSA-N butyronitrile Chemical group CCCC#N KVNRLNFWIYMESJ-UHFFFAOYSA-N 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002964 rayon Substances 0.000 description 1
- 238000007363 ring formation reaction Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 229920001897 terpolymer Polymers 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F6/38—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising unsaturated nitriles as the major constituent
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/42—Nitriles
- C08F220/44—Acrylonitrile
- C08F220/46—Acrylonitrile with carboxylic acids, sulfonic acids or salts thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/42—Nitriles
- C08F220/44—Acrylonitrile
- C08F220/48—Acrylonitrile with nitrogen-containing monomers
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/06—Wet spinning methods
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
- D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
- D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
- D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
- D01F9/20—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products
- D01F9/21—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F9/22—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from polyaddition, polycondensation or polymerisation products from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyacrylonitriles
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Artificial Filaments (AREA)
Abstract
The invention discloses a method for improving the drawability of a dry-jet wet-spun carbon fiber precursor. According to the method, acrylonitrile is used as a first monomer, an acidic second monomer and a neutral third monomer are added, azodiisobutyronitrile is used as an initiator to prepare a spinning solution, the solid content of the spinning solution is 15-16.5wt%, the intrinsic viscosity of the spinning solution is 1.43-1.55 mPa.s, the spinning solution is stretched by an air layer, and then the spinning solution is subjected to coagulation forming by a coagulation bath, washing, hot water drafting, oiling, drying, steam drafting and relaxation heat setting and then is wound to obtain a precursor. The invention selects reasonable solid content, the concentration of the spinning solution is moderate, and the molecular chain can be fully stretched; the solubility of PAN is further improved through reasonable mass ratio of acrylonitrile, acid second monomer and neutral third monomer, so that the precursor obtains larger total draft ratio.
Description
Technical Field
The invention relates to a method for improving the drawability of a dry-jet wet-spun carbon fiber precursor, belonging to the technical field of high-performance carbon fiber preparation.
Background
Carbon fibers can be produced from a variety of precursors, but only Polyacrylonitrile (PAN), rayon, and pitch are currently available for industrial production. Among the three commercial precursors, PAN is most preferred, with 90% of the carbon fibers currently used being made from PAN-based precursors. The solid content of the common spinning solution is 18-20%, the concentration of the spinning solution is moderate, the molecular chain can be fully stretched, and the drawability in the PAN production process can be effectively improved. However, PAN molecules are difficult to use as carbon fiber precursors due to strong interactions and close packing caused by butyronitrile groups. Therefore, a small amount of copolymer is generally introduced into the PAN chain to improve the solubility, spinnability, hydrophilicity and water-drawing property of the copolymer, and plays an important role in the preparation of carbon fibers. In general, it is desirable to introduce acidic copolymers of acrylic acid, methacrylic acid, itaconic acid, etc. to reduce the cyclization temperature and improve the preoxidation properties of the material, while acrylonitrile copolymers can reduce the onset temperature of PAN preoxidation, they tend to exhibit poor spinnability due to the lack of neutral comonomers in PAN. Neutral methyl acrylate and methyl methacrylate are therefore often added to improve PAN solubility, drawability and spinnability. However, it is difficult to simultaneously improve the pre-oxidizing ability and drawability of acrylonitrile terpolymer due to the difference in reactivity of the acidic comonomer and the neutral comonomer. In general, neutral copolymers have higher reactivity than acidic copolymers, which results in lower incorporation of acidic copolymers into the polymer chain. How to effectively improve the preoxidation and drawability of PAN, and preparing high-performance carbon fibers remains a challenge.
Disclosure of Invention
The invention aims to provide a method for improving the drawability of dry-jet wet-spun carbon fiber precursors.
The technical scheme for realizing the purpose of the invention is as follows:
a method for improving the drawability of a dry-jet wet spun carbon fiber precursor comprising the steps of:
(1) Taking Acrylonitrile (AN) as a first monomer, adding AN acidic second monomer and a neutral third monomer, and taking Azobisisobutyronitrile (AIBN) as AN initiator to prepare spinning solution, wherein the acidic second monomer is acrylic acid, methacrylic acid or itaconic acid, the neutral third monomer is isobutyl methacrylate, methyl methacrylate or methacrylamide, the solid content of the spinning solution is 15-16.5wt%, and the intrinsic viscosity is 1.43-1.55mPa.s;
(2) The spinning solution is stretched by an air layer, and is subjected to coagulation bath coagulation forming, water washing, hot water drafting, oiling, drying, steam drafting and relaxation heat setting, and then is wound to obtain the yarn.
Further, in the step (1), the mass ratio of the first monomer, the acidic second monomer and the neutral third monomer is AN: second monomer+third monomer=97.5 to 98:2 to 2.5, the ratio is mass percent.
Further, in the step (2), the spinning solution enters a coagulating bath through a spinneret plate, the height of an air layer is 3-10 mm, and the draft ratio of the air layer is 1.8-4; the temperature of the coagulating bath is 45-75 ℃, the concentration of dimethyl sulfoxide is 30-50%, and the draft ratio of the coagulating bath is 1.5-3. Under the condition of low temperature and concentration coagulation bath, the spinning solution rapidly carries out double diffusion, and the surface layer of the nascent fiber rapidly forms a film, so that a larger draft ratio can be obtained.
Further, in the step (2), the water washing temperature is 30-50 ℃, the hot water drafting temperature is 70-89 ℃, and the drafting ratio is 2.5-4.5.
Further, in the step (2), the drying roller in the drying process uses saturated steam for drying, and the steam pressure of the saturated steam is 0.7-1.5 MPa.
In the step (2), saturated steam is used as a medium in the steam drafting process, the steam pressure of the saturated steam is 0.4-0.6 MPa, the temperature of the saturated steam is 130-165 ℃, the steam drafting ratio is 3.8-5.5, and the crystallinity and the orientation degree of the fiber after the drafting are further improved, so that the finished product precursor is prepared.
Compared with the prior art, the invention has the following advantages:
(1) According to the invention, the concentration of the spinning solution is moderate by adjusting the solid content of the spinning solution, the molecular chain can be fully stretched, the problems of embedding, uneven dissolution and the like in the powder dissolution process due to the too high solid content are prevented, the phenomenon that DIAN knots are easily generated due to the too low solid content is prevented, and meanwhile, the performance of the precursor is not thoroughly influenced by the solvent volatilization in the precursor;
(2) The invention adopts the acrylonitrile, the acid second monomer and the neutral third monomer as polymerization monomers, and controls the mass ratio among the acrylonitrile, the acid second monomer and the neutral third monomer, thereby further improving the solubility of PAN and obtaining larger total draft ratio of the precursor.
Detailed Description
The following further describes the summary and technical aspects of the invention in conjunction with specific examples, but should not be construed as limiting the invention.
Example 1
Taking 98 parts by mass of acrylonitrile, 1 part by mass of itaconic acid, 1 part by mass of methyl methacrylate and uniformly mixing and stirring azo-bis-isobutyronitrile serving as an initiator to prepare spinning solution. The spinning dope had a solid content of 15wt% and an intrinsic viscosity of 1.55mPa.s. Stretching the prepared spinning solution through an air layer, wherein the height of the air layer is 7mm, and the draft ratio of the air layer is 2.5; and then performing coagulation forming through a coagulation bath, washing, hot water drafting, oiling, drying, steam drafting, relaxing, heat setting and winding to obtain the precursor. The process controls the temperature of the coagulating bath to 45 ℃, the concentration of dimethyl sulfoxide to 30% and the draft ratio of the coagulating bath to 2; the water washing temperature was set to 35 ℃, the hot water draft temperature was set to 75 ℃, and the draft ratio was set to 3. The drying roller in the drying and shaping process uses saturated steam for drying, and the steam pressure of the saturated steam is 0.8MPa; in the drawing process, saturated steam is used as a medium, the steam pressure of the saturated steam is 0.5MPa, the temperature of the saturated steam is 135 ℃, the steam drawing ratio is 4, and the crystallinity and the orientation degree of the drawn fiber are further improved to obtain a finished product precursor. The total draw ratio of the filaments of this example can be up to 60.
Example 2
97.5 parts by mass of acrylonitrile, 1 part by mass of acrylic acid and 1.5 parts by mass of methacrylamide were taken. And (3) uniformly mixing and stirring the azo-diisobutyronitrile serving as an initiator to prepare spinning stock solution. The spinning dope had a solid content of 16wt% and an intrinsic viscosity of 1.46mPa.s. Stretching the prepared spinning solution through an air layer, wherein the height of the air layer is 7mm, and the draft ratio of the air layer is 2.6; and then performing coagulation forming through a coagulation bath, washing, hot water drafting, oiling, drying, steam drafting, relaxing, heat setting and winding to obtain the precursor. The process controls the temperature of the coagulating bath to 50 ℃, the concentration of dimethyl sulfoxide to 35% and the draft ratio of the coagulating bath to 2.2; the water washing temperature was set to 40 ℃, the hot water draft temperature was set to 80 ℃, and the draft ratio was set to 3. The drying roller in the drying and shaping process uses saturated steam for drying, and the steam pressure of the saturated steam is 1.0MPa; in the drawing process, saturated steam is used as a medium, the steam pressure of the saturated steam is 0.5MPa, the temperature of the saturated steam is 140 ℃, the steam drawing ratio is 4.1, and the crystallinity and the orientation degree of the drawn fiber are further improved to obtain a finished product precursor. The total draft of the filaments of this example can be up to 70.356.
Example 3
Taking 98 parts by mass of acrylonitrile, 1 part by mass of methacrylic acid, 1 part by mass of isobutyl methacrylate and uniformly mixing and stirring azo-bis-isobutyronitrile serving as an initiator to prepare spinning stock solution. The spinning dope had a solid content of 16.5wt% and an intrinsic viscosity of 1.43mPa.s. Stretching the prepared spinning solution through an air layer, wherein the height of the air layer is 7mm, and the draft ratio of the air layer is 2.5; and then performing coagulation forming through a coagulation bath, washing, hot water drafting, oiling, drying, steam drafting, relaxing, heat setting and winding to obtain the precursor. The process controls the temperature of the coagulating bath to 55 ℃, the concentration of dimethyl sulfoxide to 35% and the draft ratio of the coagulating bath to 2.3; the water washing temperature was set to 45 ℃, the hot water draft temperature was set to 85 ℃, and the draft ratio was set to 3. The drying roller in the drying and shaping process uses saturated steam for drying, and the steam pressure of the saturated steam is 1.3MPa; in the drawing process, saturated steam is used as a medium, the steam pressure of the saturated steam is 0.5MPa, the temperature of the saturated steam is 150 ℃, the steam drawing ratio is 4.8, and the crystallinity and the orientation degree of the drawn fiber are further improved to obtain a finished product precursor. The total draw ratio of the filaments of this example can be up to 82.8 times.
Comparative example 1
Taking 98 parts by mass of acrylonitrile, 1 part by mass of itaconic acid, 1 part by mass of methyl methacrylate and uniformly mixing and stirring azo-bis-isobutyronitrile serving as an initiator to prepare spinning solution. The spinning dope had a solid content of 18wt% and an intrinsic viscosity of 1.38mPa.s. Stretching the prepared spinning solution through an air layer, wherein the height of the air layer is 7mm, and the draft ratio of the air layer is 2; and then performing coagulation forming through a coagulation bath, washing, hot water drafting, oiling, drying, steam drafting, relaxing, heat setting and winding to obtain the precursor. The process controls the temperature of the coagulating bath to 45 ℃, the concentration of dimethyl sulfoxide to 30% and the draft ratio of the coagulating bath to 1.7; the water washing temperature was set at 35 ℃, the hot water draft temperature was set at 75 ℃, and the draft ratio was set at 2.5. The drying roller in the drying and shaping process uses saturated steam for drying, and the steam pressure of the saturated steam is 0.8MPa; in the drawing process, saturated steam is used as a medium, the steam pressure of the saturated steam is 0.5MPa, the temperature of the saturated steam is 135 ℃, the steam drawing ratio is 3.8, and the crystallinity and the orientation degree of the drawn fiber are further improved to obtain a finished product precursor. The total draft of the comparative example precursor can be up to 32.3 times.
The total draft is reduced by too high a solids content of the dope compared to example 1.
Comparative example 2
Taking 98 parts by mass of acrylonitrile, 1 part by mass of itaconic acid, 1 part by mass of methyl methacrylate and uniformly mixing and stirring azo-bis-isobutyronitrile serving as an initiator to prepare spinning solution. The spinning dope had a solid content of 12wt% and an intrinsic viscosity of 1.85mPa.s. Stretching the prepared spinning solution through an air layer, wherein the height of the air layer is 7mm, and the draft ratio of the air layer is 2; and then performing coagulation forming through a coagulation bath, washing, hot water drafting, oiling, drying, steam drafting, relaxing, heat setting and winding to obtain the precursor. The process controls the temperature of the coagulating bath to 50 ℃, the concentration of dimethyl sulfoxide to 35% and the draft ratio of the coagulating bath to 2; the water washing temperature was set to 40 ℃, the hot water draft temperature was set to 80 ℃, and the draft ratio was set to 2.5. The drying roller in the drying and shaping process uses saturated steam for drying, and the steam pressure of the saturated steam is 1.0MPa; in the drawing process, saturated steam is used as a medium, the steam pressure of the saturated steam is 0.5MPa, the temperature of the saturated steam is 140 ℃, the steam drawing ratio is 3.8, and the crystallinity and the orientation degree of the drawn fiber are further improved to obtain a finished product precursor. The total draw ratio of the comparative example precursor can be up to 38 times.
The total draft is reduced by too low a solids content of the dope compared to example 1.
Comparative example 3
Taking 99 parts by mass of acrylonitrile and 1 part by mass of itaconic acid, and uniformly mixing and stirring the components by taking azodiisobutyronitrile as an initiator to prepare spinning solution. The spinning dope had a solid content of 16.5wt% and an intrinsic viscosity of 1.42mPa.s. Stretching the prepared spinning solution through an air layer, wherein the height of the air layer is 7mm, and the draft ratio of the air layer is 2; and then performing coagulation forming through a coagulation bath, washing, hot water drafting, oiling, drying, steam drafting, relaxing, heat setting and winding to obtain the precursor. The process controls the temperature of the coagulating bath to 55 ℃, the concentration of dimethyl sulfoxide to 35% and the draft ratio of the coagulating bath to 2; the water washing temperature was set to 45 ℃, the hot water draft temperature was set to 85 ℃, and the draft ratio was set to 2.8. The drying roller in the drying and shaping process uses saturated steam for drying, and the steam pressure of the saturated steam is 1.3MPa; in the drawing process, saturated steam is used as a medium, the steam pressure of the saturated steam is 0.5MPa, the temperature of the saturated steam is 150 ℃, the steam drawing ratio is 4, and the crystallinity and the orientation degree of the drawn fiber are further improved to obtain a finished product precursor. The total draft of the comparative example precursor can be up to 44.8 times.
In comparison with example 1, the total draft is reduced without the addition of isobutyl methacrylate.
Table 1 dope formulation and draft ratio evaluation data for each example and comparative example
Finally, it should be understood that the foregoing description is merely illustrative of the preferred embodiments of the present invention, and not intended to limit the scope of the invention, but to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention. The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that modifications and variations can be made without departing from the technical principles of the present invention, and these modifications and variations should also be regarded as the scope of the invention.
Claims (6)
1. A method for improving the drawability of a dry-jet wet spun carbon fiber precursor comprising the steps of:
(1) Preparing spinning stock solution by taking acrylonitrile as a first monomer, adding an acidic second monomer and a neutral third monomer, and taking azobisisobutyronitrile as an initiator, wherein the acidic second monomer is acrylic acid, methacrylic acid or itaconic acid, the neutral third monomer is isobutyl methacrylate, methyl methacrylate or methacrylamide, the solid content of the spinning stock solution is 15-16.5 wt%, and the intrinsic viscosity is 1.43-1.55 mPa.s;
(2) The spinning solution is stretched by an air layer, and is subjected to coagulation bath coagulation forming, water washing, hot water drafting, oiling, drying, steam drafting and relaxation heat setting, and then is wound to obtain the yarn.
2. The method of claim 1, wherein in step (1), the mass ratio of the first monomer, the acidic second monomer, and the neutral third monomer=97.5 to 98:2 to 2.5.
3. The method according to claim 1, wherein in the step (2), the spinning dope is fed into a coagulation bath through a spinneret plate, the height of an air layer is 3 to 10mm, and the draft ratio of the air layer is 1.8 to 4; the temperature of the coagulating bath is 45-75 ℃, the concentration of dimethyl sulfoxide is 30-50%, and the draft ratio of the coagulating bath is 1.5-3.
4. The method according to claim 1, wherein in the step (2), the water washing temperature is 30 to 50 ℃, the hot water drawing temperature is 70 to 89 ℃, and the drawing ratio is 2.5 to 4.5.
5. The method according to claim 1, wherein in the step (2), the drying roller in the drying process uses saturated steam for drying, and the steam pressure of the saturated steam is 0.7-1.5 MPa.
6. The method according to claim 1, wherein in the step (2), saturated steam is used as a medium in the steam drawing process, the steam pressure of the saturated steam is 0.4-0.6 MPa, the temperature of the saturated steam is 130-165 ℃, and the steam drawing ratio is 3.8-5.5.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311682376.0A CN117535815A (en) | 2023-12-08 | 2023-12-08 | Method for improving drawability of dry-jet wet-spun carbon fiber precursor |
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| CN (1) | CN117535815A (en) |
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2023
- 2023-12-08 CN CN202311682376.0A patent/CN117535815A/en active Pending
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