Classifications

• • 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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/44—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/54—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds of polymers of unsaturated nitriles
• • 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
  • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
  • D01F8/02—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from cellulose, cellulose derivatives, or proteins

Definitions

• the present invention relates to a method of making a fiber of polyacrylonitrile - cellulose acetate.
• Acrylic fiber is one of the principal varieties of synthetic fiber in the world, which is soft in hand feel, bright in color and luster and relatively good in strength and elasticity and has a good reputation as "artificial wool".
• the acrylic fiber macromolecule has irregular helical conformation and has no true crystalline structures.
• the strength of the acrylic fiber is much higher than that of natural fiber and regenerated fiber, the acid resistance of the acrylic fiber is good, and the weather resistance is good.
• Feedstock polyacrylonitrile (PAN) contains a large number of hydrophobic groups, so that the acrylic fiber is relatively poor in hygroscopicity and generates static electricity extremely easily.
• the static electricity can cause the fiber to wind or block up a machine element and affect the successful proceeding of a weaving process. Due to the accumulation of electrostatic charges on clothing, wearers easily feel uncomfortable, so that the wearability of acrylic-fiber textiles is lowered, and thus, the further development of the acrylic-fiber textiles is limited.
• An important method for modifying the antistatic property of the acrylic fiber is to blend an antistatic agent and an acrylic fiber spinning stock solution and then carry out spinning to obtain fiber.
• a frequently-used blended type antistatic agent is carbon black.
• CN101805935A discloses a novel antistatic acrylic fiber and a preparation method thereof.
• the acrylic fiber comprises carbon nano-tubes and carbon black, wherein the weight percent of the carbon nano-tubes is 1-15%, the weight percent of the carbon black is 1-3%, and the weight percent of polyacrylonitrile is 82-98%.
• the prepared fiber is black, so that the use of the prepared fiber is limited.
• the antistatic property of the acrylic fiber can also be improved by proper physical and chemical methods, but that causes environmental pollutions of different degrees.
• a doctoral dissertation, i.e., plasma antistatic treatment of acrylic fiber proposes provides a method for improving the antistatic property of the acrylic fiber through carrying out surface modification on the acrylic fiber by adopting a low-temperature plasma technology.
• the low-temperature plasma technology is water-saving, energy-saving and pollution-free and has remarkable economic and environmental protection effects.
• the method is relatively high in requirements and has certain difficulty in actual popularized application.
• Cellulose acetate fiber is good in hygroscopicity, has a moisture regain of 6%, can be dyed with disperse dyes and has good wearability. Filaments are elegant in luster and soft in hand feel, have good drapability, look exactly like real silk, are suitable for producing underwear, bathrobes, children's wear, lady's garments, indoor decorative fabrics and the like and can also be used for producing cigarette filters. However, the cellulose acetate fiber is low in strength and poor in wearability.
• copolyacrylonitrile is prepared by an aqueous-phase precipitation polymerization method in a manner of taking acrylonitrile (AN), a potential crosslinker (2-hydroxypropyl acrylate) and vinyl acetate (VAc) as monomers and taking sodium chlorate (NaClO 3 ) as an initiator.
• AN acrylonitrile
• VAc vinyl acetate
• the copolyacrylonitrile fiber which has relatively high water absorption and water retention capacity, is free of irritation and has certain strength, is obtained through preparing copolyacrylonitrile (CPAN) fiber and CPAN/cellulose acetate (CA) blended fiber (CPAN-CA) containing crosslinker through wet spinning by taking N, N-dimethylacetamide (DMAc) as a solvent, preparing copolyacrylonitrile fiber with a crosslinked structure through post-crosslinking and subjecting the fiber to basic hydrolysis.
• CPAN copolyacrylonitrile
• CA CPAN/cellulose acetate
• DMAc N-dimethylacetamide
• the front crosslinking agent and the initiator are required to be added during the preparation of copolyacrylonitrile
• the preparation method is complicated, reactions of multiple steps, i.e., aqueous-phase precipitation polymerization, wet spinning, post-crosslinking and basic hydrolysis are required to be adopted, and the condition that hydrolysis is an indispensable step for preparing the polyacrylonitrile hydrophilic fiber is pointed out.
• the content of cellulose acetate in the prepared blended fiber is 5%
• the strength of the blended fiber is maximized and is only 1.4cN/dtex, and then, the strength is lowered along with the increase of the cellulose acetate content.
• the present invention provides a method to produce a polyacrylonitrile-cellulose acetate fiber to overcome the defects that acrylic fiber is poor in hygroscopicity, and likely to cause static electricity; and meanwhile, to overcome the disadvantages that pure cellulose acetate fiber is low in strength and poor in wearability.
• the method is simple and feasible and is easy to control in process.
• the fiber of polyacrylonitrile-cellulose acetate provided by the present invention has the advantages of light weight, warm keeping, good weather resistance, good acid/base resistance, good drapability, difficulty in wrinkling, etc.; and not only is a domestic gap filled up, but also a novel fibrous raw material is provided for the textile industry.
• a preparation method of the fiber of polyacrylonitrile-cellulose acetate comprises the following steps:
• step 1) the aqueous-phase suspension polymerization reaction is carried out at a temperature of 58 DEG C to 62 DEG C and at a pH value of 2.5 to 3.5.
• a mass ratio of cellulose acetate to the powdery polyacrylonitrile is arbitrary, preferably (15-35wt%):(65-85wt%), more preferably (15-30wt%):(70-85wt%).
• a ratio of the sum of the masses of the powdery polyacrylonitrile and cellulose acetate to the mass of the solvent is (20-25.5):(74.5-80);
• the solvent is selected from dimethylacetamide, dimethyl sulfoxide, dimethylformamide or sodium thiocyanate;
• the heating means heating up to a temperature of 80 DEG C to 90 DEG C; and the cooling means cooling down to a temperature of 70 DEG C to 80 DEG C.
• step 3 the spinning is carried out at a temperature of 80 DEG C to 97 DEG C under a pressure of 0.7MPa to 0.9MPa.
• the coagulating bath is selected from an aqueous solution of dimethylacetamide, dimethyl sulfoxide, dimethylformamide or sodium thiocyanate and has a concentration of 30-55wt% and a temperature of 25 DEG C to 50 DEG C.
• the temperature adjustment means adjusting a temperature to 80 DEG C to 97 DEG C and the pressure adjustment means adjusting a pressure to 0.7MPa to 0.9MPa.
• a drafting ratio is 4 to 10; and the setting is carried out under a pressure of 200KPa to 330KPa.
• hygroscopicity and antistatic properties of the fiber Due to the characteristics of poor water absorption and hygroscopicity, low moisture regain, antistatic properties and the like, the range of application of ordinary polyacrylonitrile fiber is restricted.
• the hygroscopicity and antistatic properties of the fiber have a certain internal relationship, so that the other properties can be greatly improved through improving the water absorption and hygroscopicity of the polyacrylonitrile fiber.
• a variety of hygroscopic fibers prepared through blending polyacrylonitrile and cellulose acetate are disclosed in the prior art, and many articles in the prior art indicate that the break strength of the hygroscopic fiber is maximized and is only 1.4cN/dtex when the content of cellulose acetate is 5%.
• the inventor consciously and surprisedly discovers that, by adopting a relatively high cellulose acetate mass ratio, the strength of the fiber of polyacrylonitrile-cellulose acetate is increased, and the elongation, moisture regain and specific resistance of the polyacrylonitrile-cellulose acetate fiber are better and exceed expected ranges.
• the polyacrylonitrile-cellulose acetate fiber has good comprehensive performance and has a break strength of 2.3CN/dtex to 3.0CN/dtex, a breaking elongation of 32-40%, a moisture regain of 2-3% and a specific resistance of 9.0 ⁇ 10 8 ⁇ •CM to 4.8 ⁇ 10 9 ⁇ •CM.
• the determination of break strength and breaking elongation is carried out according to provisions of GB/T 14337; the determination of moisture regain is carried out according to provisions of GB/T 6503; and the determination of specific resistance is carried out according to provisions of GB/T 14342-1993.
• the fiber of polyacrylonitrile-cellulose acetate is prepared through dissolving polyacrylonitrile and cellulose acetate with a solvent to obtain a colloid and then carrying out wet spinning.
• blended fiber of polyacrylonitrile and cellulose acetate is generally prepared through carrying out wet spinning, then, carrying out post-crosslinking, and then, carrying out basic hydrolysis, wherein the condition that hydrolysis is an indispensable step for preparing the polyacrylonitrile hydrophilic fiber is pointed out.
• the fiber of polyacrylonitrile-cellulose acetate provided by the present invention can be obtained through only dissolving polyacrylonitrile and cellulose acetate with a solvent to obtain a colloid and then carrying out wet spinning without crosslinking, post-crosslinking and basic hydrolysis.
• the process route is simple, so that processing steps are greatly simplified, the working efficiency is increased, and batch production is facilitated; and physical indexes of the produced polyacrylonitrile-cellulose acetate fiber are closer to indexes of the conventional acrylic fiber.
• polyacrylonitrile is formed from acrylonitrile and vinyl acetate, wherein a mass ratio of acrylonitrile to vinyl acetate is (92-94wt%):(6-8wt%).
• polyacrylonitrile is generally prepared from acrylonitrile, vinyl acetate and other ingredients such as a front crosslinking agent, an initiator, three single auxiliaries, an oxidant and a reducer.
• polyacrylonitrile is prepared from acrylonitrile and vinyl acetate which are in a mass ratio of (92-94wt%):(6-8wt%).
• a ratio of the sum of the masses of polyacrylonitrile and cellulose acetate to the mass of the solvent is (20-25.5):(74.5-80).
• the object of the present invention is to provide a preparation method of the fiber of polyacrylonitrile-cellulose acetate.
• the method is simple and feasible and is easy to control in process.
• the preparation method of the polyacrylonitrile-cellulose acetate fiber comprises the following steps:
• copolyacrylonitrile is prepared by an aqueous-phase precipitation polymerization method, taking acrylonitrile (AN), a potential crosslinker (2-hydroxypropyl acrylate) and vinyl acetate (VAc) as monomers and taking sodium chlorate (NaClO 3 ) as an initiator.
• AN acrylonitrile
• VAc vinyl acetate
• Copolyacrylonitrile (CPAN) fiber and CPAN/cellulose acetate (CA) blended fiber (CPAN-CA) with crosslinker is obtained through wet spinning by taking N, N-dimethylacetamide (DMAc) as a solvent, and then the copolyacrylonitrile-base fiber with a crosslinked structure is prepared by post-crosslinking, and is subjected to basic hydrolysis to obtain copolyacrylonitrile-base fiber, which has relatively high water absorption and water retention capacity and certain strength.
• a front crosslinking agent and the initiator are required to be added during the preparation of copolyacrylonitrile, the preparation method is complicated, and reactions of multiple steps, i.e., aqueous-phase precipitation polymerization, wet spinning, post-crosslinking and basic hydrolysis are required to be adopted.
• the condition that hydrolysis is an indispensable step for preparing the polyacrylonitrile hydrophilic fiber is emphasized. Obviously, in the prior art, it is generally believed that hydrolysis is an
• the fiber of polyacrylonitrile-cellulose acetate can be obtained by only adopting two monomers, i.e., acrylonitrile and vinyl acetate, carrying out aqueous-phase suspension polymerization to obtain polyacrylonitrile and then subjecting polyacrylonitrile and cellulose acetate to wet spinning without crosslinking, post-crosslinking and basic hydrolysis.
• the process route is simple, so that processing steps are greatly simplified, the working efficiency is increased, and batch production is facilitated; and physical indexes of the produced fiber of polyacrylonitrile-cellulose acetate are closer to indexes of the conventional acrylic fiber.
• step 1) the aqueous-phase suspension polymerization reaction is carried out at a temperature of 58 DEG C to 62 DEG C and at a pH value of 2.5 to 3.5.
• a mass ratio of cellulose acetate to the powdery polyacrylonitrile is arbitrary, preferably (15-35wt%):(65-85wt%), more preferably (15-30wt%):(70-85wt%).
• a ratio of the sum of the masses of the powdery polyacrylonitrile and cellulose acetate to the mass of the solvent is (20-25.5):(74.5-80);
• the solvent is selected from dimethylacetamide, dimethyl sulfoxide, dimethylformamide or sodium thiocyanate;
• the heating means heating up to a temperature of 80 DEG C to 90 DEG C; and the cooling means cooling down to a temperature of 70 DEG C to 80 DEG C.
• step 3 the spinning is carried out at a temperature of 80 DEG C to 97 DEG C under a pressure of 0.7MPa to 0.9MPa.
• the coagulating bath is selected from an aqueous solution of dimethylacetamide, dimethyl sulfoxide, dimethylformamide or sodium thiocyanate and has a concentration of 30-55wt% and a temperature of 25 DEG C to 50 DEG C.
• the temperature adjustment means adjusting a temperature to 80 DEG C to 97 DEG C and the pressure adjustment means adjusting a pressure to 0.7MPa to 0.9MPa.
• a drafting ratio is 4 to 10; and the setting is carried out under a pressure of 200KPa to 330KPa.
• the preparation method provided by the present invention is simple and feasible in process, and the prepared polyacrylonitrile-cellulose acetate fiber is good in comprehensive performance and has a break strength of 2.3CN/dtex to 3.0CN/dtex, a breaking elongation of 32-40%, a moisture regain of 2-3% and a specific resistance of 9.0 ⁇ 10 8 ⁇ •CM to 4.8 ⁇ 10 9 ⁇ •CM.
• the fiber of polyacrylonitrile-cellulose acetate and the preparation method thereof have the following advantages:
• Polyacrylonitrile was prepared by the means of an intermittent aqueous-phase precipitation polymerization method. Specifically, white powdery polyacrylonitrile was prepared by controlling a temperature in a four-mouthed flask to 45+/-2 DEG C through a constant-temperature circulating water bath, then adding acrylonitrile (AN), vinyl acetate (VAc) and a potential crosslinker (HQ) into the flask according to a certain ratio under nitrogen protection, adjusting a pH value to about 2, and adding an initiator, i.e., NaClO 3 -Na 2 SO 3 to initiate a polymerization reaction, controlling polymerization time to 1.5 hours, adding NaOH to terminate the reaction, and then carrying out filtering and baking.
• AN acrylonitrile
• VAc vinyl acetate
• HQ potential crosslinker
• the blended fiber was obtained as the following step: blending the prepared white powdery polyacrylonitrile and cellulose acetate separately according to mass ratios of 85/15, 80/20, 75/25, 70/30 and 65/35, preparing a DMAc spinning solution according to a concentration of 20%, putting the spinning solution into a spinning kettle, carrying out uniform stirring and mixing at a certain rate of revolution to obtain a brown and transparent uniform solution, carrying out vacuumized deaeration at a temperature of 60 DEG C, spinning nascent fiber by a wet spinning process in a manner of taking a 40% DMAc aqueous solution as a coagulating bath, and carried out coagulating shaping, drafting, relaxing and drying to obtain the blended fiber.
• Blended fiber with a crosslinked network structure was obtained through naturally airing the above-mentioned prepared fiber, and subjecting the aired fiber to crosslinking for appropriate time in a baking oven with a temperature of 180 DEG C to allow functional groups inside fiber macromolecules to be subjected to a dehydrated crosslinking reaction.
• Blended fiber with hydrophilicity was obtained through putting blended staple fiber into alkali liquor tanks of different concentrations and different temperatures, controlling hydrolysis time, taking out the hydrolyzed fiber, neutralizing residual alkali liquor on the surface of the fiber with hydrochloric acid, sufficiently washing the fiber with distilled water, and carrying out natural air-drying.
• Test samples the fiber of polyacrylonitrile-cellulose acetate provided by the present invention was prepared through blending polyacrylonitrile and cellulose acetate separately according to mass ratios of 85/15, 80/20, 75/25, 70/30 and 65/35 according to the method provided by the embodiment 1 of the present invention.
• Control samples the blended fiber in the prior art was prepared through blending polyacrylonitrile and cellulose acetate separately according to mass ratios of 85/15, 80/20, 75/25, 70/30 and 65/35 according to the method provided by the comparative example.
• test example main technical indexes of the fiber of polyacrylonitrile-cellulose acetate prepared by the method provided by the present invention and main technical indexes of the conventional acrylic fiber and cellulose acetate fiber were tested separately, and results were separately shown in a table 2 and a table 3 as follows. Determination provisions were the same as those in the test example 1.
• Table 2 Main technical indexes of the polyacrylonitrile-cellulose acetate fiber prepared by the method provided by the present invention and main technical indexes of the conventional acrylic fiber Specifica tions (dtex) Variety (glazed) Size (dtex) Break strength (CN/dtex) Breaking elongation (%) Moisture regain (%) Specific resistance ( ⁇ • CM) 1.33 polyacrylonitril e-cellulose acetate fiber 1.4 2.5 34 2.63 9.27 ⁇ 10 8 1.33 conventional acrylic fiber 1.31 2.69 35 0.81 2.75 ⁇ 10 12 1.67 polyacrylonitril e-cellulose acetate fiber 1.78 2.68 36 2.1 4.73 ⁇ 10 9 1.67 conventional acrylic fiber 1.70 2.71 38 0.93 9.13 ⁇ 10 11
• Table 3 Main technical indexes of the fiber of polyacrylonitrile-cellulose acetate prepared by the method provided by the present invention and main technical indexes of the conventional cellulose acetate fiber Specifications (dtex) Variety (glazed) Break strength (CN/dtex) Breaking elongation (%)
• the fiber of polyacrylonitrile-cellulose acetate was prepared from polyacrylonitrile and cellulose acetate in different proportioning ratios according to the method provided by the embodiment 1, the moisture regain and specific resistance of the fiber of polyacrylonitrile-cellulose acetate were investigated, and results were shown in a table 4. Determination provisions were the same as those in the test example 1.
• a mass ratio of cellulose acetate to polyacrylonitrile is preferably (15-35wt%):(65-85wt%), more preferably (15-30wt%):(70-85wt%).

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• 2015
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