• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present disclosure discloses a process for making cellulosic fibers. The process comprises the following steps: 1) Mixing pulp pulp with an aqueous NMMO solution having a weight concentration of 60% - 85%, preferably 70% - 76%, in order to obtain a uniform mixture; 2) subjecting the obtained uniform mixture to dewatering for swelling and dissolving, and deaeration to obtain a cellulose spinning stock solution; 3) Introducing the cellulose spinning stock solution into a spinning machine after filtration and heat exchange, and introducing into a coagulation system after extrusion through a spinning package and air cooling, and then coagulating in an NMMO coagulation bath with a weight concentration of 50% - 72% by nascent To get fibers; and 4) washing the nascent fibers to obtain a fiber filament bundle and then performing treatment in a subsequent area to obtain cellulosic fibers. The present disclosure can greatly reduce the investment in the equipment, simplify the process, lower the energy consumption and the application cost, and facilitate the safe manufacture, improve the uniformity and the mechanical properties of the fiber, making the process for industrial production with high efficiency and low consumption can be used.
    公开号:AT521561A2
    申请号:T9514/2016
    申请日:2016-12-27
    公开日:2020-02-15
    发明作者:Sun Yushan；Li Ting；Cheng Chunzu；Ding Libing；Cai Jian；Luo Qiang；Zhou Yunan；Zhang Dong；Xu Jigang
    申请人:China Textile Academy；
    IPC主号:
    专利说明:

    Vo r -Fahr-em for the production of cellulose fibers
    Technical part
    The present disclosure relates to the technical field of cellulose and in particular to a process for the production of cellulose fibers.
    Background of the Invention
    In the process of producing cellulose fibers by dissolving cellulose in an aqueous solution of N-methylmorpholine-N-oxide (NMMO), the swelling of the cellulose and the dissolution processes and the effects of NMMO on the cellulose are directly related to the stability of the spinning and the properties of the finished product. Furthermore, the concentration of a spinning solution and the fact whether a processing method is energy-saving or not are directly related to the economic benefits and industrial spread of process technology. From this point of view, an energy-saving and highly efficient process for the production of cellulose fibers in industrial production is of particular importance.
    In the prior art, in the process for producing cellulosic fibers, the concentration of an aqueous NMMO solution to be recovered is low, as described in CN101089262A and CN1318115A, generally 10% - 30%. The concentration of an aqueous starting solution of NMMO needed to prepare a spinning stock solution is high, as described in CN1468889A and CN1635203A, generally 80% - 88%. The volume of evaporated water required for recovery is huge, and an energy-saving multi-effect evaporator is generally used; however, concentrating with a large concentration difference still requires a multi-stage evaporator and consumes a large amount of water, electricity, and steam, and the investment cost for a multi-effect evaporator is high, which makes the production cost too high and it is difficult to an industrial production with high efficiency and low
    2/28
    To achieve consumption.
    In addition, a single coagulation step at low concentration easily results in strong coagulation, resulting in the formation of a sheath and core fiber structure that is detrimental to the uniformity and mechanical properties of the fiber. Furthermore, the highly concentrated aqueous NMMA solution of high concentration required for the production of the stock solution has a safety risk during evaporation, storage and transportation. There is also a problem of repeated energy consumption during the preparation of the stock solution, and the equipment and the process flow in the production of the stock solution are too expensive.
    For this reason, the present disclosure is offered.
    Summary
    The object of the present disclosure is to avoid the disadvantages of the prior art and to offer a method for producing cellulose fibers. By extensively using an aqueous NMMO solution of a relatively lower concentration to directly swell the cellulose, an aqueous NMMO solution of a relatively higher concentration as a coagulation bath to coagulate a bundle of filaments, and using a better water-saving step for washing and a better energy-saving step Concentration by evaporation technique, the present disclosure can greatly reduce the investment cost of the equipment, simplify the process, lower the energy consumption and the application cost, and facilitate the safe manufacture, improve the uniformity and mechanical properties of the fiber, so that the manufacturing technique is better for industrial production with high efficiency and low consumption can be used.
    To solve the technical problems described above, the technical solution to the present disclosure is as follows:
    3/28
    A method of making cellulosic fibers, the method comprising the steps of:
    1) Mixing the cellulose pulp with an aqueous NMMO
    Solution of a concentration by weight of 60% - 85%, preferably 70% - 76%, to obtain a uniform solution;
    2) dewater the uniform solution obtained
    Swelling and dissolution, and venting to a
    To obtain stock solution for spinning the cellulose;
    3) placing the stock solution for spinning the cellulose in a spinning machine after filtering and heat exchange, and placing in a coagulation system after extrusion through a spin pack and cooling by air, and then coagulation in an NMMO coagulation bath with a weight concentration of 50% to 72% to get a nascent fiber; and
    4) washing the nascent fiber in order to obtain fiber filament bundles and subsequent treatment of the cellulose fiber obtained in a further step.
    According to the method for producing cellulose fibers according to the present disclosure, in the step of producing the spinning stock solution, the aqueous NMMO solution of a relatively low concentration is uniformly mixed directly with the pulp pulp and thereby the safety risks during evaporation, storage and transportation the highly concentrated aqueous NMMO solution is avoided, and the energy consumption required for the production of the highly concentrated aqueous NMMO solution is reduced. A concentration of the fed aqueous NMMO solution of 70% -76% is preferred here in order to balance the uniformity of the mixture which is produced by mixing the aqueous NMMO solution and the pulp and the expediency of the subsequent transport in a homogeneous phase to guarantee. The pulp does not require additional treatment, which avoids the problem of repeated energy consumption during manufacture,
    4/28 the investment costs in the equipment are greatly reduced and the processes in the production of the stock solution are simplified overall.
    In the present disclosure, the pulp pulp comprises one or a mixture of several pulp grade pulp, bamboo pulp, starch pulp and hemp pulp grade pulp. The pulp can be a mixture of different degrees and / or types of polymerization, no additional treatment is required, and the weight concentration of the cellulose is 8% - 22%. The weight concentration of the NMMO of an aqueous NMMO solution for feeding is 60% - 85%, preferably 70% - 76%.
    In the area of cellulose fiber shaping, the coagulation system achieves coagulation by using an aqueous NMMO solution of a relatively higher concentration. The process of coagulation of the fiber is slowed down and the formation of shell-core structures of the fiber is avoided. In addition, the undiffused solvent acts as a plasticizer during fiber drawing, which facilitates the formation of a densified structure within the fiber. The coagulation system is also beneficial for the homogenization of the fibers and the improvement of the mechanical properties.
    In a preferred embodiment of the method of the present disclosure, a low-concentration aqueous NMMO solution obtained after washing is continuously added to the coagulation system in step 3) in the course of the method, and a high-concentration aqueous NMMO solution is discharged into a recovery area , a weight concentration of the NMMO aqueous solution in the coagulation bath of the coagulation system is kept constant under the condition of effective circulation of the NMMO aqueous solution of the coagulation bath, and the high concentration aqueous NMMO solution entering the recovery area is subjected to a recovery treatment and then treated with the Pulp pulp mixed in step 1).
    5/28
    In the present disclosure, the NMMO aqueous solution of low concentration means an aqueous NMMO solution of a weight concentration that is higher than 0% and not higher than 50%; and the high concentration aqueous NMMO solution means an aqueous NMMO solution with a weight concentration higher than 50% and not higher than 72%.
    In the current process, the difference between the concentration of the NMMO to be recovered and the concentration required for the feed is too large and is generally greater than 50%. A
    Concentration by 50% corresponds to the evaporation of the same amount of water as pure solvent. The volume of the evaporated water is large and the investment costs in the equipment and the energy consumption are high. On this basis, the concentration difference to be evaporated is reduced and, in a preferred embodiment, is reduced to below 26%, the volume of the evaporated water is reduced by at least half, and the energy consumption and the investment costs in the apparatus are also greatly reduced. In view of this concentration difference, an appropriate, suitable manufacturing method had to be found, and the present disclosure has been obtained after the inventor has conducted a variety of experiments. A suitable concentration for the feed was finally determined by reducing the concentration of the aqueous NMMO solution required for the feed as far as possible while taking into account the mixing effect and the stability of the uniformity and the swelling effect during the subsequent transport. This was consistent with an optimal scheme for the preparation of the stock solution, i.e. a continuous gradual drainage, and a drainage scheme could be determined according to the working conditions in order to guarantee the uniform production of the stock solution under all working conditions. In addition, the optimal range for the concentration of the coagulation bath was finally determined by improving the concentration of the
    6/28
    Coagulation bath taking into account the coagulation effect and the influence on the shape and properties of the fibers. With a supportive multi-stage coagulation system, a better water-saving washing step and a more energy-saving evaporation technique, the entire process is very energy-saving compared to the current technology, and uniform cellulose fibers can be produced with a high yield.
    Furthermore, the aqueous NMMO solution, which is to be recovered in the recovery area, is subjected to a coarse filtration, adsorption on activated carbon and successive filtering on a macroporous resin before it enters the evaporation area in order to determine the required concentration of the solution for the feed for a mixture with the pulp pulp in step 1). A flow diagram of the process is shown in Fig.l.
    In the present disclosure, the NMMO aqueous solution for recovery in the recovery area is a high concentration aqueous NMMO solution that. exits the coagulation system.
    In the evaporation area, the number of evaporation steps is determined according to the concentration difference between the aqueous NMMO solution that is to be recovered and a concentrated aqueous NMMO solution that is required for feeding, preferably the concentration difference between the aqueous NMMO solution that is to be recovered and the aqueous NMMO solution required for the feed is less than 26%, and the number of evaporation steps is not greater than two.
    In the present disclosure, a better energy-saving evaporation technique is chosen, the evaporated water vapor is compressed and then returns to an evaporator as a heat source; after the system is stable, no more raw steam is consumed and it becomes home
    7/28 used relatively cheap electricity. The evaporated water obtained in the evaporation enters a washing area to enable cyclical use.
    In step 2), a dewatering process comprises a one-step dewatering or a continuous stepwise dewatering, preferably the dewatering process comprises the continuous stepwise dewatering.
    In the present disclosure, continuous step drainage is preferred and the retention time of each step can be adjusted. The continuous gradual dewatering not only swells the mixture and improves film formation, but also facilitates the subsequent dissolution, which facilitates the uniform and high-quality production of the stock solution; and it promotes uniform swelling and dissolution, and the production of the highly concentrated and uniform spinning stock solution can be achieved, and the weight concentration of the cellulose is improved. For industrial production, the improvement in cellulose concentration means an increase in productivity, which is economically advantageous.
    In step 3) the coagulation system is a one-stage coagulation system or a multi-stage coagulation system, preferably the coagulation system is a multi-stage coagulation system; and the temperature of the coagulation bath of each stage can be independently set in the range of 10-8 ° C.
    In the multi-stage coagulation system, the NMMO concentrations of the coagulation baths gradually decrease in each stage, and the NMMO concentration of the coagulation bath in the first stage is higher than 50% and lower than 72%, preferably not lower than 51% and not higher than 65%.
    8/28
    In step 4), a washing process comprises a single-range wash or a multi-range wash, preferably the wash process is a multi-range spray wash, and the wash water and the fibers move against one another; and the temperature of the rinse water is in the range of 10-80 ° C, preferably the temperatures in each area are gradually lower. In the present disclosure, multigrade laundry is chosen as the preferred washing method; Due to the multi-stage arrangement for the rinsing, the concentrations in each area are gradually lower and the temperatures of the wash water are different for each area, so that the consumption of the wash water is saved as much as possible and the amount of evaporated water recovered is indirectly reduced, and that Energy consumption is greatly reduced.
    In the multi-area spray washing, the volume of the spray water in each area is strictly controlled, and the washing water is successively returned to the previous area for washing in the previous area; the concentrations of NMMO in the spray water gradually decrease in each area, and the spray water in the end area comes from water from the recovered water vapor.
    Using the above technique, the following advantages are achieved by the present disclosure compared to the prior art.
    According to the manufacturing method with low energy consumption for cellulosic fibers as set forth in the present disclosure, in the manufacturing area of the stock solution, the aqueous NMMO solution of a relatively low concentration is uniformly mixed directly with the pulp pulp and thus the safety risks during evaporation, storage and transportation the highly concentrated aqueous NMMO solution avoided; and the pulp does not require additional treatment, so that the problem of repeated energy consumption during manufacture is avoided, the investment in the equipment
    9/28 is greatly reduced and overall the process steps for the preparation of the stock solution are simplified. In addition, due to continuous, gradual dewatering, the swelling and film formation of the mixture is better, the subsequent dissolution is facilitated and thus the uniform and high-quality production of the stock solution is facilitated. With this technique, the production of the highly concentrated and uniform spinning stock solution can be achieved and the weight concentration of the cellulose can be improved; and in industrial production, increased productivity means savings.
    In the present disclosure, the coagulation system in the forming area of the cellulose fibers achieves coagulation by using an aqueous NMMA solution with a relatively high concentration. This slows down the coagulation process of the fibers and prevents the formation of a shell-core structure of the fibers. In addition, the undiffused solvent acts as a plasticizer during fiber drawing, which facilitates the formation of a densified structure inside the fiber. And the coagulation system is cheaper for the homogenization of the fibers and the improvement of the mechanical properties.
    In the present disclosure, in a preferred water-saving washing method, due to a multi-range type of spray washing, the concentrations in each area are gradually lower, and the temperatures of the washing water in each area are different, so that the consumption of washing water is largely saved and that The amount of evaporated water recovered is indirectly reduced and energy consumption is greatly reduced. In the present disclosure, an evaporation technique with higher energy savings is chosen, the evaporated water vapor is compressed and then returned to an evaporator as a heat source; as soon as the system is stable, no further raw steam is used and mainly only relatively cheap electricity is used.
    10/28
    In addition, according to the manufacturing method for cellulosic fibers according to the present disclosure, an aqueous NMMO solution with a relatively high concentration (compared with the conventional method) is recovered, an aqueous NMMO solution with a relatively low concentration (compared with the conventional method) fed in, the concentration difference of the aqueous NMMO solution to be evaporated is greatly reduced, the number of evaporation steps is reduced, the volume of the evaporated water is greatly reduced, the process flow is simplified and thus the investment in the evaporation apparatus is greatly reduced and the energy consumption is high degraded; in the entire recovery system, both the concentration of NMMA solvent and the process temperature are not high, which enables safe manufacture, storage and transport.
    Thus, the low energy manufacturing technology for cellulosic fiber provided by the present disclosure significantly reduces the cost of the industry.
    The specific embodiments of the present disclosure are described in detail below with reference to the figures.
    Brief description of the pictures
    FIG. 1 is a schematic flow diagram of a preferred manufacturing method according to the present disclosure;
    Figure 2 is a schematic flow diagram of the apparatus for the method according to the present disclosure;
    3 is a schematic diagram of the continuous step drainage of the process according to the present disclosure;
    4 is a schematic diagram of a multi-stage coagulation system of the method according to the present disclosure;
    11/28
    5 is a schematic diagram of a multi-range spray wash of the method according to the present disclosure;
    here are: 1 - mixer; 2 - drainage device; 3 filters; 4 - heat exchanger; 5 - spinning machine (containing a spinneret); 6 - coagulation system; 7 - washing
    Contraption; 8th - Device for Aftercare.It's closed note that these Illustrations and Descriptions did not think are, the scope the present. Disclosure in any way to restrict, but serve The concept the present Disclosure to Specialist by reference on
    to explain special embodiments.
    Precise description
    In order to clarify the objects, technical arrangements and advantages of the embodiments of the present disclosure, the technical arrangements of the embodiments are clearly and completely described below with reference to the illustrations of the embodiments of the present disclosure; the following embodiments are used to describe the present disclosure, but do not limit the scope of the present disclosure.
    Referring to Figs. 1 through 5, the low energy consumption manufacturing method for cellulosic fibers according to the present disclosure includes the special steps: an aqueous NMMO solution and untreated pulp pulp are mixed directly and uniformly, and a uniform mixture has been made in the mixer 1 obtained at a certain temperature and with mechanical stirring. The resulting uniform mixture was evaporated enough to dewater for swelling and dissolved in a dewatering device 2 and deaerated by one-step or continuous step-by-step evaporation dewatering to obtain a stock solution of cellulose. The spinning stock solution prepared was filtered through filter 3 and
    12/28 subjected to heat exchange in a heat exchanger 4 and then introduced into a spinning machine 5 and extruded through a spinning package and cooled with air and then introduced into a coagulation system 6 in order to obtain nascent fibers. The nascent fibers obtained were washed by the washer 7 to obtain fiber-filament bundles, and then the filament bundles were put in an after-treatment apparatus, cut, dried, crimped, etc. or directly dried and crimped by hot rolling to obtain cellulose fibers.
    Referring to Fig. 1, the aqueous NMMO solution is subjected to coarse filtration, adsorption on activated carbon and filtration through macroporous resin in a recovery area and then introduced into an evaporation area for the solvent, evaporated, and then introduced into an evaporator and then into an evaporator The separator, the water vapor generated by the evaporator and the concentrated product with the desired NMMO concentration, which were obtained by the concentration by evaporation, are separated. The water vapor is compressed and returned to the evaporator as a heat source, and the concentrated product with the required NMMO concentration obtained by the evaporation concentration returns to dissolve cellulose. The evaporation concentration method used in the present disclosure compresses and reuses the water vapor evaporated from the evaporator as a heat source, which is returned to the evaporator, in addition to the initial introduction of raw steam, the raw steam no longer being consumed after stabilization, and is concentrated to the desired NMMO concentration by evaporation to be recovered to dissolve the cellulose. The high concentration aqueous NMMO solution, which is overflowed during fiber production, is recycled to keep the system balanced. In the embodiments, the conditions of energy consumption result from the concentration differences between the aqueous NMMO solution that is fed to the recovery and the concentrated aqueous NMMO13 / 28
    Solution needed for feeding and the number of evaporation steps.
    Embodiment 1
    The aqueous NMMO solution with a weight concentration of 72% and an untreated pulp pulp were directly and uniformly mixed, and a uniform mixture was obtained in the mixer 1 at a certain temperature and with mechanical stirring. Here, the pulp was produced by mixing wood pulp of high and low degree of polymerization, the weight ratio of wood pulp DP: 800 to wood pulp D: 450 being 8:92 and the cellulose concentration being 12%.
    The uniform mixture obtained was evaporated sufficiently to dewater it for swelling, and dissolved in a dewatering device 2 and deaerated by continuous two-stage evaporation dewatering to obtain a cellulose stock solution for spinning, see FIG. 3. The first step in an evaporation-dewatering process is primarily a mixing process for full swelling, and the retention time was 20 min; The second step of the evaporation-dewatering process mainly serves to remove excess moisture and to dissolve the cellulose in a solution with a homogeneous phase, i.e. the stock solution for spinning. The spinning stock solution has a refractive index of 1.48365 and a viscosity of 2026 Pa.s.
    The spinning stock solution prepared was subjected to two-stage filtration (a 30 mesh filter was used in the coarse filtration; and a 15 mesh filter was used in the fine filtration) in the filter 3, and by heat exchange in the heat exchanger 4 to a temperature of 90 ° C, and then the solution is introduced into the spinning machine 5 and extracted by the spin pack and cooled with air, then introduced into the coagulation system 6, which is a two-stage coagulation system, see FIG. 4. The first stage coagulation bath has an NMMO concentration of 55% and a temperature of
    14/28
    Room temperature; the second stage coagulation bath has an NMMO concentration of 30% and a temperature of 40 ° C, whereby the nascent fiber was obtained. The stable concentration of the coagulation bath was achieved by continuous recycling.
    The nascent fibers were subjected to a wash in the washing device 7, see Fig.5. The washing device is a four-area spray washing device, the spray water of the first area having a concentration of 15% and a temperature of 60 ° C, the spray water of the second area having a concentration of 8% and a temperature of 50 ° C, which Spray water of the third area has a concentration of 3% and a temperature of 40 ° C, the spray water of the fourth area has a concentration of 0% and a temperature of 40 ° C and comes from recovered evaporated water; the spray water and the fibers move in the opposite direction. The wash water was successively returned to the previous step and is sprayed in the previous step to obtain filament bundles. The bundles of filaments then entered the aftertreatment device 8 and were treated in the following areas to obtain cellulose fibers.
    The aqueous NMMO solution in the recovery area was subjected to coarse filtration, adsorption on activated carbon and filtration through a macroporous resin, and then entered the solvent evaporation area with a two-stage evaporation. A new type of evaporation technique is used, in which the vaporized water vapor is compressed and then returned to the evaporator as a heat source, and after stabilization, no further raw steam is used and mainly electrical energy is used. The aqueous NMMO solution was concentrated to 72% NMMO and used to dissolve the cellulose. The evaporated water from the evaporation entered the wash area as the source for the spray water of the last area to achieve the goal of cyclical use.
    15/28
    The fibers produced had a strength of 4.43 cN / dtex and a CV value of 5.13%.
    Embodiment 2
    The cellulose fibers are produced under the same conditions as those in embodiment 1 with the following differences:
    the aqueous NMMO solution with a weight concentration of 76% was fed; and the pulp was made by mixing wood pulp DP: 400 and bamboo pulp DP: 300 in a mixing ratio of 52:48, and the cellulose concentration was 16%. The uniform mixture was subjected to continuous three-stage evaporation and dewatering in the dewatering device 2 to obtain the cellulose spinning solution, see Fig. 3, the retention time in each of the first two steps was 9 minutes and the spinning stock solution had a refractive index of 1.48623 and a viscosity of 2849 Pa.s.
    The spinning stock solution produced was brought to 90 ° C. by heat exchange using a heat exchanger 4 and then extruded through the spinning package and then entered the coagulation system 6, the coagulation system being a three-stage coagulation system, see FIG. 4. The first stage of the coagulation bath has an NMMO concentration of 70% and a temperature of 35 ° C; the second stage of the coagulation bath has an NMMO concentration of 55% and a temperature of room temperature and the third stage of the coagulation bath has an NMMO concentration of 40% and a temperature of 50 ° C.
    The nascent fibers were subjected to a wash in the washer 7, the washer 7 being a nine-area spray washer, see Fig.5. The spray water of the first area has a concentration of 31% and a temperature of 80 ° C; the spray water of the second area has a concentration of 23% and a temperature of 80 ° C; the spray water of the third area has a concentration of 17% and a temperature of
    16/28 ° C; the spray water of the fourth area has a concentration of 12% and a temperature of 60 ° C; the spray water of the fifth area has a concentration of 8% and a temperature of 50 ° C; the spray water of the sixth area has a concentration of 5% and a temperature of 50 ° C; the spray water of the seventh area has a concentration of 3% and a temperature of 40 ° C; the spray water of the eighth area has a concentration of 1% and a temperature of 40 ° C; the spray water of the ninth area has a concentration of 0% and a temperature of room temperature.
    The aqueous NMMO solution in the recovery area was subjected to one-stage evaporation and concentrated to 76% NMMO and used to dissolve the cellulose.
    The fibers produced have a strength of 4.31 cN / dtex and a CV value of 4.58%.
    Embodiment 3
    The cellulose fibers are produced under the same conditions as those in embodiment 1 with the following differences:
    the aqueous NMMO solution with a weight concentration of 74% was fed; and the pulp was made from wood pulp DP: 300 and the cellulose concentration was 18%. The obtained uniform mixture was subjected to continuous two-stage evaporation and dewatering in the dewatering device 2 to obtain the cellulose spinning solution, see Fig. 3, the retention time in the first step was 25 minutes and the spinning stock solution had a refractive index of 1.48714 and a viscosity of 2415 Pa.s.
    The spinning stock solution produced was brought to 90 ° C. by heat exchange using a heat exchanger 4 and then extruded through the spinning package and then entered the coagulation system 6, the coagulation system 6 being a three-stage coagulation system, see FIG. 4. The first stage of the coagulation bath has an NMMO17 / 28
    Concentration of 65% and a temperature of 30 ° C; the second stage of the coagulation bath has an NMMO concentration of 35% and a temperature of 40 ° C; and the third stage of the coagulation bath has an NMMO concentration of 15% and a temperature of 70 ° C.
    The nascent fibers were subjected to a wash in the washer 7, the washer 7 being a three-zone spray washer, see Fig.5. The spray water of the first area has a concentration of 7% and a temperature of 60 ° C; the spray water of the second area has a concentration of 3% and a temperature of 50 ° C; the spray water of the third area has a concentration of 0% and a temperature of room temperature.
    The aqueous NMMO solution in the recovery area was subjected to one-stage evaporation and concentrated to 74% NMMO and used to dissolve the cellulose.
    The fibers produced have a strength of 4.13 cN / dtex and a CV value of 4.79%.
    Embodiment 4
    The cellulose fibers are produced under the same conditions as those in embodiment 1 with the following differences:
    the aqueous NMMO solution with a weight concentration of 75% was fed; and the pulp was made by mixing cotton pulp DP: 300 and hemp pulp DP: 300 in a mixing ratio of 80:20, and the cellulose concentration was 20%. The obtained uniform mixture was subjected to continuous two-stage evaporation and dewatering in the dewatering device 2 to obtain the cellulose spinning solution, see Fig. 3, the retention time in the first step was 35 minutes and the spinning stock solution had a refractive index of 1.48910 and a viscosity of 3920 Pa.s.
    18/28
    The spinning stock solution produced was brought to 100 ° C. by heat exchange using a heat exchanger 4 and then extruded through the spinning package and entered the coagulation system 6, the coagulation system 6 being a single-stage coagulation system, see FIG. 4. The coagulation bath has an NMMO concentration of 51% and a temperature of room temperature.
    The nascent fibers were subjected to a wash in the washing device 7, the washing device 7 being a four-area spray washing device, see FIG. 5. The spray water of the first area has a concentration of 25% and a temperature of 70 ° C; the spray water of the second area has a concentration of 9% and a temperature of 50 ° C; the spray water of the third area has a concentration of 3% and a temperature of room temperature; the spray water of the fourth area has a concentration of 0% and a temperature of room temperature.
    The aqueous NMMO solution in the recovery area was subjected to two-stage evaporation and concentrated to 75% NMMO and used to dissolve the cellulose.
    The fibers produced have a strength of 4.22 cN / dtex and a CV value of 7.51%.
    Embodiment 5
    The cellulose fibers are produced under the same conditions as those in embodiment 1 with the following differences:
    the aqueous NMMO solution with a weight concentration of 70% was fed; the obtained uniform mixture was subjected to continuous two-stage evaporation and dewatering in the dewatering device 2 to obtain the cellulose spinning solution, see Fig. 3, the retention time in the first step was 22 min and the spinning stock solution had a refractive index of 1.48315.
    19/28
    The aqueous NMMO solution in the recovery area was subjected to one-stage evaporation and concentrated to 70% NMMO and used to dissolve the cellulose.
    The fibers produced have a strength of 4.42 cN / dtex and a CV value of 5.21%.
    Embodiment 6
    The cellulose fibers are produced under the same conditions as those in embodiment 1 with the following differences:
    the aqueous NMMO solution with a weight concentration of 60% was fed; the obtained uniform mixture was subjected to continuous three-stage evaporation and dewatering in the dewatering device 2 to obtain the cellulose spinning solution, see Fig. 3, the retention time in the first two steps was 20 minutes and the spinning stock solution had a refractive index of 1.48432.
    The aqueous NMMO solution in the recovery area was subjected to one-stage evaporation and concentrated to 60% NMMO and used to dissolve the cellulose.
    The fibers produced have a strength of 4.40 cN / dtex and a CV value of 5.37%.
    Embodiment 7
    The cellulose fibers are produced under the same conditions as those in embodiment 1 with the following differences:
    the aqueous NMMO solution with a weight concentration of 85% was fed; the uniform mixture obtained was subjected to continuous one-stage evaporation and dewatering in the dewatering device 2 to obtain the cellulose spinning solution, see Fig. 3, and the spinning stock solution had a refractive index of 1.48613.
    20/28
    The aqueous NMMO solution in the recovery area was subjected to two-stage evaporation and concentrated to 85% NMMO and used to dissolve the cellulose.
    The fibers produced have a strength of 4.38 cN / dtex and a CV value of 5.53%.
    According to the low energy consumption method for producing cellulosic fibers offered by embodiments of the present disclosure, the present disclosure can be used as a coagulation bath by extensively using an aqueous NMMO solution with a relatively low concentration to directly swell the cellulose and an aqueous NMMO solution with a relatively higher concentration to coagulate filament bundles, and by using a better water-saving method of washing and a better energy-saving technique of concentration by evaporation, greatly reduce the investment cost for the apparatus, simplify the method, lower the energy consumption and the equipment cost, and facilitate the safe production which Improve uniformity and the mechanical properties of the fibers, so that the process technology can be better used for industrial production with high efficiency and low consumption. Although the preferred embodiments of the present disclosure are described, additional changes and modifications to these embodiments may be made by those skilled in the art once the basic inventive concept is known. The appended claims are therefore intended to explain that these claims embrace the preferred embodiments, as well as all changes and modifications that fall within the scope of the present disclosure.
    It is apparent that various changes and modifications to the present disclosure can be made by those skilled in the art without departing from the spirit and scope of the present disclosure. Accordingly, it is the intent of the present disclosure to include all such changes and modifications, provided that these changes and modifications to the
    21/28 present disclosure fall within the scope of the claims of the present disclosure and equivalent techniques thereof.
    权利要求:
    Claims (10)
    [1]
    1) Mixing pulp pulp with an aqueous NMMO
    Solution of a weight concentration of 60% - 85%, preferably 70% - 76%, to obtain a uniform mixture;
    1. A method of making cellulosic fibers, the method comprising the following steps:
    [2]
    2. The method according to claim 1, wherein during the course of the method, an aqueous NMMO solution of low concentration, which is obtained after washing, is continuously added to the coagulation system in step 3), an aqueous NMMO solution of high concentration in a recovery area is introduced, a weight concentration of a coagulation bath of NMMO aqueous solution in the coagulation system is kept stable under the condition of effective circulation of the coagulation bath of NMMO aqueous solution, and the high concentration aqueous NMMO solution entering the recovery area is subjected to a recovery treatment and then mixed with the pulp in step 1).
    23/28
    2) subjecting the obtained uniform mixture to dewatering for swelling and dissolving, and deaeration to obtain a cellulose spinning stock solution;
    [3]
    The method of claim 2, wherein the NMMO aqueous solution to be recovered in the recovery area is successively subjected to a coarse filtration, adsorption on activated carbon and filtration through macroporous resin, and then enters an evaporation area to be up to one for feeding the mixture with the Cellulose pulp in step 1) required concentration to be concentrated.
    3) Introducing the cellulose spinning stock solution into a spinning machine after filtering and heat exchange, and introducing it into a coagulation system after extrusion by means of a spin pack and cooling by air, and subsequent coagulation in an NMMO coagulation bath with a weight concentration of 50% - 72% to get a nascent fiber; and
    [4]
    4. The method according to claim 3, wherein in the evaporation area the number of evaporation stages is determined according to the concentration difference between the aqueous NMMO solution to be recovered and an aqueous NMMO solution with a concentration required for the feed;
    preferably, the difference in concentration between the NMMO aqueous solution to be recovered and the NMMO aqueous solution having a concentration required for feeding is less than 26%, and the number of evaporation steps is not more than two.
    4) Wash the nascent fiber to obtain fiber filament bundles and then treat it in a subsequent area to obtain a cellulosic fiber.
    [5]
    5. The method according to claim 4, wherein in the
    Evaporation area the water vapor generated by the evaporation is compressed and then returned to an evaporator as a heat source.
    [6]
    6. The method according to any one of claims 1 to 5, wherein in step 2) a dewatering method comprises one-step dewatering or continuous stepwise dewatering, preferably the dewatering method comprises continuous stepwise dewatering; and the retention time can be set for each step.
    [7]
    7. The method according to any one of claims 1 to 6, wherein in step 3) the coagulation system is a single-stage coagulation system or a multi-stage coagulation system, preferably the coagulation system is a multi-stage coagulation system; and the temperature
    24/28 of the coagulation bath of each level can be set independently in a range of 10 80 ° C.
    [8]
    The method of claim 7, wherein in the multi-stage coagulation system the NMMO concentrations of the coagulation baths of all stages gradually decrease, and an NMMO concentration of a first stage coagulation bath is higher than 50% and lower than 72%, preferably not lower than 51% and not higher than 65%.
    [9]
    The method according to any one of claims 1 to 8, wherein in step 4) a washing method comprises a single-range wash or a multi-range wash, preferably the washing method is a multi-range spray wash, and the wash water and fibers move in opposite directions; and the temperature of the wash water is in the range of 10-80 ° C, and preferably the temperatures of all areas gradually decrease.
    [10]
    10. The method according to claim 9, wherein in the multi-range spray washing, the volume of the spray water of each area is strictly controlled and the washing water is successively returned to the previous area for washing in the previous area; and the NMMO concentrations of the spray water gradually decrease in all areas and the wash water of the last area comes from the water obtained by water vapor recovery.
    类似技术:
    公开号 | 公开日 | 专利标题
    DE69723582T2|2004-05-13|REGENERATED CELLULOSE FIBERS AND METHOD FOR THEIR PRODUCTION
    DE969389C|1958-05-29|Process for the production of cotton-like threads, fibers or ribbons by deforming viscose
    DE2830683C3|1982-04-01|Process for the production of a solid starting material for the preparation of a cellulose solution and use of this starting material
    AT521561A2|2020-02-15|Process for the production of cellulose fibers
    EP2929071B1|2017-02-01|Method for producing a cellulosic molded body
    EP0044534A2|1982-01-27|High-modulus polyacryl nitrile filaments and fibres, and process for manufacturing them
    DE2851273A1|1979-10-18|WET SPINNING PROCESS FOR THE PRODUCTION OF HIGH DRAWN ACRYLNITRILE POLYMER FIBERS
    DE3541034C2|1992-08-13|
    AT521560A2|2020-02-15|Process for the production of a cellulose solution and device therefor
    EP1129241B1|2004-01-21|Method for producing cellulosic fibers
    DE2433235A1|1975-02-13|METHOD OF REMOVING HEMICELLULOSIS FROM CIRCULATED HEMICELLULOSIC ALKALINE SOLUTIONS
    DE2752743C2|1983-03-03|Process for the production of filaments or films by spinning a cellulose solution
    EP0003135A2|1979-07-25|Process for improving the solubility of viscose
    DE1129656B|1962-05-17|Process for the production of cellulose hydrate threads or fibers by spinning viscose
    DE2657144C2|1982-12-02|Process for making hydrophilic fibers
    DE3040970A1|1982-06-03|DRY WOVEN POLYACRYLNITRILE PROFILE FIBERS AND FEDERS AND A METHOD FOR THE PRODUCTION THEREOF
    AT413285B|2006-01-15|Washing of absorbent material, e.g. lyocell fiber tow, involves several stages in contra-flow with appreciable amounts of absorbed liquid carried to next stage
    EP0178293B1|1990-05-02|Process for the production of cellulose threads and fibres, and device for carrying out the process
    EP1224343A1|2002-07-24|Method for producing cellulose shaped-bodies
    AT310923B|1973-10-25|Process for making fibers from regenerated cellulose with high crimp and high elongation
    DE1669494C3|1976-02-12|Process for the production of polynose fibers
    DE1494745A1|1969-12-11|Process for the production of threads or fibers from viscose
    AT205651B|1959-10-10|Process for making threads, fibers and films and the like Like. Made of viscose
    AT275016B|1969-10-10|Process for the production of polyester fibers
    DE2909785A1|1979-10-04|PROCESS FOR THE MANUFACTURING OF FIBERS OR FIBERS FROM POLYMERIZED CONTAINING ACRYLIC NITRILE WITH INCREASED WATER-RETENTION CAPACITY
    同族专利:
    公开号 | 公开日
    CN106222771A|2016-12-14|
    WO2018014510A1|2018-01-25|
    US20190292683A1|2019-09-26|
    CN106222771B|2019-02-22|
    US11124899B2|2021-09-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE2541335C3|1975-09-17|1986-06-19|Bayer Ag, 5090 Leverkusen|Process for the continuous removal of residual solvent from dry-spun acrylonitrile threads|
    US4246221A|1979-03-02|1981-01-20|Akzona Incorporated|Process for shaped cellulose article prepared from a solution containing cellulose dissolved in a tertiary amine N-oxide solvent|
    WO1998022642A1|1996-11-21|1998-05-28|Toyo Boseki Kabushiki Kaisha|Regenerated cellulosic fibers and process for producing the same|
    CA2438445C|2002-12-26|2006-11-28|Hyosung Corporation|Lyocell multi-filament for tire cord and method of producing the same|
    CN1282773C|2005-05-30|2006-11-01|武汉大学|Method for preparing regenerative cellulose fiber by two-step coagulating bath process|
    KR100824980B1|2006-12-28|2008-04-28|주식회사 효성|Cellulose multi-filament with lower coefficient of variation of section diameter|
    AT505787B1|2007-09-18|2009-06-15|Chemiefaser Lenzing Ag|lyocell|
    CN101280476B|2008-05-23|2010-04-14|宜宾丝丽雅集团有限公司|Recovery method for NMMO solvent in fibre production by solvent method|
    CN101736426B|2008-11-07|2012-01-25|中国科学院化学研究所|Method for preparing regenerated cellulose fibers from plant fibrous pulp of reeds and stalks|
    CN101942712B|2009-07-07|2012-05-23|中国科学院化学研究所|Recovery method of N-methylmorpholine oxide solvent in process of producing regenerated cellulose fibre by solvent method|
    CN101988216B|2009-08-04|2014-08-06|上海太平洋纺织机械成套设备有限公司|Method for circularly preparing solvents in Lyocell fiber preparation process|
    CN102234852B|2010-04-21|2013-04-10|聚隆纤维股份有限公司|Solvent recovery method of Lyocell fibers|
    US9090997B2|2012-03-05|2015-07-28|Acelon Chemical And Fiber Corporation|Fabrication of natural cellulose fiber with flame-retarding capability|
    KR101703404B1|2012-05-21|2017-02-06|가부시키가이샤 브리지스톤|Production method for purified polysaccharide fibers, purified polysaccharide fibers, fiber-rubber complex, and tire|
    EP2719801A1|2012-10-10|2014-04-16|Aurotec GmbH|Spinning bath and method for solidifying a moulded part|
    JP2014227619A|2013-05-21|2014-12-08|株式会社ブリヂストン|Method of producing refined polysaccharide fiber, refined polysaccharide fiber and tire|
    KR101466692B1|2013-12-02|2014-12-01|동양제강 주식회사|Apparatus for extracting solvent|
    CN105037753B|2015-06-01|2017-12-05|中国纺织科学研究院|The preparation technology and its equipment of a kind of cellulose solution|
    KR20170079531A|2015-12-30|2017-07-10|코오롱인더스트리 주식회사|Lyocell Fiber and the method for making it|
    CN106222771B|2016-07-22|2019-02-22|中国纺织科学研究院有限公司|A kind of preparation method of cellulose fibre|CN106222771B|2016-07-22|2019-02-22|中国纺织科学研究院有限公司|A kind of preparation method of cellulose fibre|
    CN110592695A|2019-10-12|2019-12-20|淮安天然丝纺织科技有限公司|Preparation method of cellulose filament fibers|
    CN111101215A|2019-12-24|2020-05-05|中国纺织科学研究院有限公司|Preparation method of cellulose fiber tows|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    CN201610587548.XA|CN106222771B|2016-07-22|2016-07-22|A kind of preparation method of cellulose fibre|
    PCT/CN2016/112375|WO2018014510A1|2016-07-22|2016-12-27|Method for preparing cellulose fibre|
    [返回顶部]