A semi-continuous polymerization production process and device for multi-element copolymer polyurethane elastic fiber

Abstract

The application provides a kind of multi-copolymerization polyurethane elastic fiber semi-continuous polymerization device, comprising: prepolymerization section, chain extension reaction section and deployment section, the chain extension reaction section includes: high-speed mixing reactor, static tubular chain extension reactor connected with the high-speed mixing reactor, the termination reaction section includes: dynamic mixing reactor, static tubular termination reactor connected with the dynamic mixing reactor.The application also provides a kind of multi-copolymerization polyurethane elastic fiber semi-continuous polymerization process, chain extender and terminator are added step by step, so that the polymerization process is easy to control, solve the problem of inaccurate product molecular weight and viscosity control in the reaction process. Flexible adjustment of intermittent pre-polymerization time and temperature is realized, so that the molecular weight and viscosity of the product after chain extension reaction are accurately controlled, and flexible replacement of a variety of different raw materials is met.

Description

Technical Field

[0001] This invention belongs to the field of polymer polymerization technology and relates to a semi-continuous production process and apparatus for multi-component copolymer elastic fibers, specifically a semi-continuous production process and apparatus for multi-component copolymer polyurethane elastic fibers. Background Technology

[0002] The raw materials for polyurethane elastomer production mainly fall into three categories: oligomeric polyols, polyisocyanates, and chain extenders (crosslinking agents). The oligomeric polyols used in polyurethane can be categorized into polyether-type and polyester-type.

[0003] Currently, the main industrial production process of polyurethane uses polyether glycol (PTMEG) and diisocyanate as raw materials to form a prepolymer under certain reaction temperature and time conditions. After the prepolymer is dissolved in a solvent, diamine is added to carry out a chain growth reaction to form a block copolymer solution. After adding additives, the solution is mixed, filtered, degassed, and processed to produce a spinning solution with uniform properties.

[0004] The shortcomings of existing technology are: 1. PTMEG is used as a raw material for continuous polymerization followed by spinning. The raw material is singular, consisting only of PTMEG with different molecular weights, and the process parameters are also different. 2. In terms of equipment, the prepolymerization reaction uses a continuous flow static tubular reactor, and the reaction time and temperature cannot be flexibly adjusted according to the different raw materials PTMEG; 3. The chain extension reaction uses a continuous flow high-speed mixing reactor and a mixed amine process for the chain extension reaction, which makes it impossible to arbitrarily control the viscosity of the polymer after chain extension.

[0005] In spandex production, controlling the viscosity of the polyurethane raw material is crucial; raw materials with unacceptable viscosity cannot be used for spinning. The viscosity of the polyurethane raw material can be controlled by adjusting the temperature of the water in the insulation jacket of the raw material storage tank and by adjusting the stirring speed of the agitator. Summary of the Invention

[0006] This application addresses the problems in the prior art where the prepolymerization reaction uses a continuous-flow static tubular reactor, and the reaction time and temperature cannot be flexibly adjusted according to different PTMEG raw materials. It also addresses the issues in the chain extension reaction using a continuous-flow high-speed mixing reactor with mixed amines, where the viscosity of the polymer after chain extension cannot be arbitrarily controlled. This application proposes a reaction equipment and process that allows for flexible adjustment of reaction time and temperature, enabling precise control of the viscosity of the product after the chain extension reaction and accommodating flexible replacement of various raw materials. Furthermore, considering the significant impact of PTMEG price fluctuations on spandex production costs and the limitation of using only PTMEG as a raw material on the development of differentiated products, this application proposes a method for preparing polyurethane elastic fibers using polyols containing ether and ester bonds. This broadens the selection of raw materials, effectively controls production costs, and allows for the production of various differentiated products based on demand, thanks to the wide variety of polyols containing ether and ester bonds.

[0007] This invention is achieved through the following technical solution: A semi-continuous polymerization production apparatus for multi-component copolymer polyurethane elastic fibers includes: a prepolymerization section, a chain extender section, and a blending section. The prepolymerization section is located before the chain extender section and is used to provide chain extender raw materials to the chain extender section. The blending section is used to provide chain extender and terminator to the chain extender section. The components of the prepolymerization section, chain extender section, and blending section are connected by pipelines and pumping devices. The chain extender section includes: a chain extender reaction section and a termination reaction section.

[0008] The chain extension reaction section includes: a high-speed mixing reactor and a static tubular chain extension reactor connected to the high-speed mixing reactor.

[0009] The termination reaction section includes: a dynamic mixing reactor and a static tubular termination reactor connected to the dynamic mixing reactor.

[0010] The polymerization process in the prepolymerization process is exothermic, and the temperature of the reactants gradually increases as polymerization progresses. Initially, the reaction temperature is 70±2℃. To control the material temperature, multiple different chain extension and termination reaction devices are set up. Heating devices can be used to flexibly control the material temperature, and the reaction time can also be flexibly controlled. By setting the chain extension and termination reactions in different devices, the entire chain extension and termination reaction is carried out separately. Each device is equipped with a sampling port, allowing for continuous sampling and viscosity measurement of the product, enabling monitoring of the polymer viscosity at every stage. Furthermore, since different raw materials can be added to the same equipment, the chain extension and termination reaction devices of this application are applicable to different polymerization processes, improving the flexibility of equipment operation.

[0011] In order to improve the preparation efficiency of spandex spinning solution and to add functional additives without affecting the overall reaction process, a functional additive addition section and a spinning solution maturation section are set sequentially after the termination reaction section.

[0012] A static tubular ADD mixer is installed after the termination reaction section to mix the functional additives and the chain-extended polyurethane raw material. A polyurethane raw material storage tank, a static spinning raw material mixer, and a spinning raw material storage tank are also installed sequentially after the static tubular ADD mixer.

[0013] Based on the above technical solution, in order to achieve continuous addition of chain extenders and terminators, the chain extender storage device in the blending section is further connected to the high-speed mixing reactor, and the terminator storage device in the blending section is connected to the dynamic mixing reactor.

[0014] The present invention also provides a semi-continuous polymerization production process for multi-component copolymer polyurethane elastic fibers, including a prepolymerization process, a chain extension process, and a functional blending process. The chain extension process is divided into a chain extension reaction step and a termination reaction step carried out sequentially in different reaction equipment.

[0015] The prepolymerization process is as follows: Polydiols containing ether and ester bonds and 4,4'-diphenylmethane diisocyanate raw materials are fed into a prepolymerization reactor in a ratio of 5:1 to 4:1. Under stirring, the reaction temperature is controlled at 68 to 72°C. After the reaction is complete, sufficient DMAC is added to the prepolymerization reactor. After stirring and adding, the material is transferred to a prepolymer buffer tank.

[0016] The chain extension reaction step is as follows: First, the prepolymer is mixed and stirred at high speed. When the temperature of the prepolymer reaches 40±2℃, a chain extender is added to the prepolymer. When the viscosity of the liquid at the outlet of the high-speed mixer reaches 2000±400 poise, the chain extension reaction material is continuously fed into a static tubular chain extender reactor to continue the chain extender reaction. After the chain extension reaction material has fully reacted in the static tubular chain extender reactor, the reaction is terminated.

[0017] The termination reaction process steps are as follows: The polymer in the static tubular chain extender reactor is transferred to the dynamic mixing reactor. At the same time, a terminator is added to the dynamic mixing reactor. During the addition of the terminator, when the solution temperature reaches 50℃±2℃, the material temperature in the dynamic mixing reactor is maintained at 45℃±2℃ by circulating the refrigerant in the jacket of the dynamic mixing reactor. When the polymer in the dynamic mixing reactor reaches the target viscosity, the polymer is transferred to the static tubular terminator reactor for thorough mixing and formulation.

[0018] The formulation process is as follows: when the polymerization solution is transferred from the static tubular termination reactor to the static tubular ADD mixer, the auxiliary agent DMAC solution is added simultaneously, and after thorough mixing, the solution is transferred to the polyurethane solution storage tank.

[0019] The functional preparation process is as follows: when transferring the polymerization stock solution from the static tubular termination reactor to the static tubular ADD mixer, zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant and other additives are added simultaneously with a mixed solution of DMAC. After thorough mixing, the stock solution is transferred to the polyurethane stock solution storage tank.

[0020] Preferably, the polydiol containing ether and ester bonds is one or more of diethylene adipate ester diol, diadipic adipate ester diol, and neopentyl adipate ester diol.

[0021] Preferably, the chain extender is one of 1,2-propanediamine, ethylenediamine, or a combination thereof.

[0022] Preferably, the terminating agent is an amine with 2 to 10 carbon atoms, such as ethylamine, propylamine, butylamine, or diethylamine.

[0023] The key technical effects of this application are: 1. This invention employs a semi-continuous process. A two-step mixing process—a high-speed mixing reactor and a dynamic mixing reactor—is used to achieve the semi-continuous polymerization process. The novel multi-component copolymer polyurethane elastic fiber semi-continuous polymerization device of this invention has a wide range of applicable raw materials and can be flexibly changed.

[0024] 2. In terms of raw material usage, this application uses polydiols containing ether and ester bonds, which solves the problem that the production cost of spandex is greatly affected by the fluctuation of PTMEG price, and that using PTMEG alone as a raw material restricts the development of differentiated products. Using polydiols containing ether and ester bonds broadens the selection of raw materials, can effectively control production costs, and has a wide variety of polydiols containing ether and ester bonds, which can be used to produce various differentiated products according to demand.

[0025] 3. This application employs a semi-continuous polymerization process. In terms of equipment, a high-speed mixing reactor, a static tubular chain extender reactor, a dynamic mixing reactor, and a static tubular termination reactor are incorporated to form a semi-continuous polymerization process. Simultaneously, the chain extender and termination agent are added stepwise, making the polymerization process easier to control and solving the problem of inaccurate product viscosity control during the reaction. This allows for flexible adjustment of the intermittent prepolymerization reaction time and temperature, enabling precise control of the molecular weight and viscosity of the product after the chain extension reaction, and accommodating flexible replacement of various raw materials.

[0026] 4. The polymerization apparatus of the present invention is equipped with heating devices for each reactor and mixer, which makes the control of process parameters more flexible and meets the needs of raw material changes and process parameter changes in actual production. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the semi-continuous production device for multi-component copolymer polyurethane elastic fibers in this application. Figure 2 A schematic diagram of the overall structure of the production equipment used in Comparative Example 1; Figure 3 This is a schematic diagram of the overall structure of the production equipment used in Comparative Example 2; Figure 4 A schematic diagram of the overall structure of the production equipment used in Comparative Example 3; In the diagram, 100 is the prepolymerization section; 101 is the raw material tank for polydiols containing ether and ester bonds; 102 is the prepolymerization reactor; 103 is the prepolymer buffer tank; 104 is the feed port for polydiols containing ether and ester bonds; 105 is the first DMAC solvent feed port; and 106 is the diisocyanate feed port. 200. Chain extender section; 210. Chain extender reaction section; 220. Termination reaction section; 211. High-speed mixing reactor; 212. Static tubular chain extender reactor; 221. Dynamic mixing reactor; 222. Static tubular termination reactor; 300. Blending section; 301. Chain extender addition port; 302. Terminator addition port; 303. Second DMAC solvent feeding port; 311. Chain extender preparation device; 312. Chain extender storage device; 321. Terminator preparation device; 322. Terminator storage device; 400. Functional additive addition section; 401. Functional additive feeding port; 402. Static tubular ADD mixer; 500, Spinning solution maturation section; 501, Polyurethane solution storage tank; 502, Static spinning solution mixer; 503, Spinning solution storage tank. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0029] Regarding embodiments of the device: like Figure 1A semi-continuous polymerization apparatus for multi-component copolymer polyurethane elastic fibers includes: a prepolymerization section 100, a chain extender section 200, and a blending section 300. The prepolymerization section 100 is located before the chain extender section 200 and is used to provide chain extender raw materials to the chain extender section 200. The blending section 300 is used to provide chain extender and terminator to the chain extender section 200. The components of the prepolymerization section 100, the chain extender section 200, and the blending section 300 are connected by pipelines and pumping devices. The chain extender section 200 includes: a chain extension reaction section 210 and a termination reaction section 220.

[0030] In one embodiment of this application, the chain extension reaction section 210 and the termination reaction section 220 are arranged separately, and the equipment of the chain extension reaction section 210 and the termination reaction section 220 can be any combination of a high-speed mixing reactor and / or a static tubular reactor.

[0031] In a preferred embodiment, the chain extension reaction section 210 includes: a high-speed mixing reactor 211 and a static tubular chain extension reactor 212 connected to the high-speed mixing reactor 211.

[0032] In a preferred embodiment, the termination reaction section 220 includes: a dynamic mixing reactor 221 and a static tubular termination reactor 222 connected to the dynamic mixing reactor 221.

[0033] In this embodiment, a functional additive addition section 400 and a spinning solution maturation section 500 are sequentially arranged after the termination reaction section 220. Specifically, the functional additive addition section 400 includes a functional additive inlet 401 and a static tubular ADD mixer 402; the spinning solution maturation section 500 includes a polyurethane solution storage tank 501, a static spinning solution mixer 502, and a spinning solution storage tank 503 arranged sequentially. The spinning solution maturation section 500 is located after the functional additive addition section 400.

[0034] In a preferred embodiment, the chain extender storage device 312 of the blending section 300 is connected to the high-speed mixing reactor 211, and the terminator storage device 322 of the blending section 300 is connected to the dynamic mixing reactor 221. The chain extender storage device 312 is disposed in a chain extender preparation system, which also includes a chain extender preparation device 311, positioned before the chain extender storage device 312. The terminator storage device 322 is disposed in a terminator preparation system, which also includes a terminator preparation device 321, positioned before the terminator storage device 322.

[0035] The prepolymerization section 100 includes a prepolymerization reactor 102 and a prepolymer buffer tank 103 disposed after the prepolymerization reactor 102.

[0036] In this embodiment, the reactors used in the prepolymerization section 100 and the blending section 300 of the multi-component copolymer polyurethane elastic fiber semi-continuous polymerization device include, but are not limited to, tank reactors and trough reactors. The storage device used can be a tank storage device or a trough reactor. This embodiment does not impose any specific restrictions.

[0037] The specific implementation process of the semi-continuous polymerization apparatus for multi-component copolymer polyurethane elastic fibers in this embodiment is as follows: Prepolymer synthesis: Prepolymer synthesis is completed in the prepolymerization section 100. Specifically, the polydiol containing ether and ester bonds stored in the polydiol raw material tank 101 containing ether and ester bonds is pumped into the prepolymerization reactor 102. DMAC solvent and diisocyanate are added into the prepolymerization reactor 102 through the first DMAC solvent inlet 105 and the diisocyanate inlet 106, respectively, to carry out the prepolymerization reaction. After the reaction is completed, the obtained prepolymer is stored in the prepolymer buffer tank 103.

[0038] Formulation of the chain extender: In the formulation section 300, the chain extender is introduced into the chain extender formulation device 311 through the chain extender addition port 301, and simultaneously, DMAC solvent is introduced into the chain extender formulation device 311 through the second DMAC solvent addition port 303 to formulate the chain extender. The formulated chain extender is then stored in the chain extender storage device 312. The terminator is introduced into the terminator formulation device 321 through the terminator addition port 302, and simultaneously, DMAC solvent is introduced into the terminator formulation device 321 through the second DMAC solvent addition port 303 to formulate the chain extender. The formulated terminator is then stored in the terminator storage device 322.

[0039] Prepolymer chain extension process: The prepolymer in the prepolymer buffer tank 103 and the chain extender in the chain extender storage device 312 are fed into the high-speed mixing reactor 211 for high-speed mixing, and then enter the static tubular chain extender reactor 212 for chain extension reaction. After setting the chain extension reaction time, the chain-extended polymer and the terminator in the terminator storage device 322 are fed into the dynamic mixing reactor 221 for mixing. After mixing, it enters the static tubular termination reactor 222 for termination reaction. After the termination reaction is completed, functional additives are added into the static tubular ADD mixer 402 through the functional additive feed port 401, and then fed into the polyurethane raw material storage tank 501. The raw materials in multiple polyurethane raw material storage tanks are mixed by the static spinning raw material mixer 502 and then fed into the spinning raw material storage tank 503 for maturation, waiting for spinning.

[0040] In this embodiment, heating devices are installed outside all types of storage and reaction layouts to control the temperature of the reactors and containers.

[0041] 2. Examples of the process Example 1 100 kg of poly(neopentyl adipate) glycol and 20 kg of 4,4'-diphenylmethane diisocyanate (MDI) were fed into the prepolymerization reactor 102. At this time, the mass ratio of the reactants poly(neopentyl adipate) glycol to 4,4'-diphenylmethane diisocyanate (MDI) was 5:1. Under stirring, the reaction temperature was controlled at 70±2℃. After reacting for 120 minutes, 180 kg of dimethylacetamide (DMAC) was added to the prepolymerization reactor 102 and stirred thoroughly. After the dimethylacetamide was added, the material was transferred to the prepolymer buffer tank 103. The prepolymer is sent from the prepolymer buffer tank 102 to the high-speed mixer 211 for stirring. At this time, the stirring power of the high-speed mixer is 23kW. When the internal temperature of the high-speed mixer reaches 40±2℃, 23kg of chain extender is added. The chain extender is a mixture of 1,2-propanediamine, ethylenediamine and DMAC, wherein the mass ratio of 1,2-propanediamine and ethylenediamine is 8:2, and the mass fraction of 1,2-propanediamine and ethylenediamine in the mixture is 7%. The viscosity of the liquid at the outlet of the high-speed mixer is controlled at 2000±400 poise. Then, a gear pump is used to continuously pass the solution in the high-speed mixer through a thin tube and into the static tubular chain extender reactor 212. After staying in the static tubular chain extender reactor 212 for 30 seconds, the viscosity of the material reaches 4000±200 poise. The polymer is then transported from the static tubular chain extender reactor 212 to the dynamic mixing reactor 221. At the same time, 6.1 kg of terminator is added to the dynamic mixing reactor 221 and stirred thoroughly. At this time, the stirring power of the dynamic mixing reactor is 11 kW. The terminator is a mixture of diethylamine and DMAC, in which diethylamine accounts for 7% of the mass fraction of the terminator mixture. The terminator is added over 30 seconds.

[0042] During the addition of the terminator, when the solution temperature reaches 50°C, cooling is achieved using refrigerant circulation in the jacket of the dynamic mixing reactor 221 to maintain the material temperature in the dynamic mixing reactor 221 at 45°C. The viscosity of the polymer in the dynamic mixing reactor 221 is monitored. When the polymer in the dynamic mixing reactor 221 reaches the target viscosity of 5000±200 poise, the polymer is transferred to the static tubular terminator reactor 222 and mixed statically for 20 minutes.

[0043] After static mixing, when the material viscosity reaches 6000±200 poise, 10.11 kg of additives are added simultaneously when the polymerization stock solution is transferred from the static tubular termination reactor 222 to the static tubular ADD mixer 402. The additives are a mixture of zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant, and DMAC solution in a mass fraction ratio of 180:50:30:20:450. After mixing for 150 minutes, polyurethane stock solution is obtained. During the preparation process, the actual measured parameters are recorded, as shown in Table 1.

[0044] After spinning the polyurethane raw material, the material properties of the spandex were tested. The obtained polyurethane elastic fiber sample was stretched to 100%, treated with hot air at 190℃ for 90 seconds, and the mechanical properties were tested using a tensile testing machine, as shown in Table 3.

[0045] Example 2: 100 kg of poly(ethylene glycol adipate) and 22.2 kg of 4,4'-diphenylmethane diisocyanate (MDI) were fed into the prepolymerization reactor 102. At this time, the mass ratio of the reactants poly(ethylene glycol adipate) to 4,4'-diphenylmethane diisocyanate (MDI) was 4.5:1. Under stirring, the reaction temperature was controlled at 70±2℃ and the reaction was carried out for 120 minutes. Then, 183 kg of dimethylacetamide (DMAC) was added to the prepolymerization reactor 102 and stirred thoroughly. After the dimethylacetamide was added, the material was transferred to the prepolymer buffer tank 103. The material is sent from the prepolymer buffer tank 103 to the high-speed mixer 211 for stirring. At this time, the stirring power of the high-speed mixer is 23kW. When the internal temperature of the high-speed mixer 211 reaches 40±2℃, 30kg of chain extender is added. The chain extender is a mixture of 1,2-propanediamine and DMAC, wherein 1,2-propanediamine accounts for 7% of the mass fraction of the mixture. The viscosity of the liquid at the outlet of the high-speed mixer 211 is controlled at 2000±400 poise. Then, the solution in the high-speed mixer 211 is continuously pumped through a thin tube into the static tubular chain extender reactor 212 using a gear pump. After staying in the static tubular chain extender reactor 212 for 30 seconds, the viscosity of the material reaches 4000±200 poise. The polymer is then transported from the static tubular chain extender reactor 212 to the dynamic mixing reactor 221. At the same time, 7.97 kg of terminator is added to the dynamic mixing reactor 221 and stirred thoroughly. At this time, the stirring power of the dynamic mixing reactor is 11 kW. The terminator is a mixture of diethylamine and DMAC, in which diethylamine accounts for 7% of the mass fraction of the terminator mixture. The terminator is added over 30 seconds.

[0046] During the addition of the terminator, when the solution temperature reaches 50°C, cooling is achieved using refrigerant circulation in the jacket of the dynamic mixing reactor 221 to maintain the material temperature in the dynamic mixing reactor 221 at 45°C. The viscosity of the polymer in the dynamic mixing reactor 221 is monitored. When the polymer in the dynamic mixing reactor 221 reaches the target viscosity of 5000±200 poise, the polymer is transferred to the static tubular terminator reactor 222 and mixed statically for 20 minutes.

[0047] After static mixing, when the material viscosity reaches 6000±200 poise, 10.32 kg of additives are added simultaneously when the polymerization stock solution is transferred from the static tubular termination reactor 222 to the static tubular ADD mixer 402. The additives are a mixture of zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant, and DMAC solution in a mass fraction ratio of 180:50:30:20:450. After mixing for 150 minutes, the polyurethane stock solution is obtained. Actual measured parameters were recorded during the preparation process, as shown in Table 1.

[0048] After spinning the polyurethane raw material, the material properties of the spandex were tested. The obtained polyurethane elastic fiber sample was stretched to 100%, treated with hot air at 190℃ for 90 seconds, and the mechanical properties were tested using a tensile testing machine, as shown in Table 3.

[0049] Example 3: 100 kg of poly(diadipate adipate diol) and 25 kg of 4,4'-diphenylmethane diisocyanate (MDI) were fed into the prepolymerization reactor 102. At this time, the mass ratio of the reactants poly(diadipate adipate diol) to 4,4'-diphenylmethane diisocyanate (MDI) was 4:1. Under stirring, the reaction temperature was controlled at 70±2℃ and the reaction was carried out for 120 minutes. Then, 201 kg of dimethylacetamide (DMAC) was added to the prepolymerization reactor 102 and stirred thoroughly. After the dimethylacetamide was added, the material was transferred to the prepolymer buffer tank 103. The material is sent from the prepolymer buffer tank 103 to the high-speed mixer 211 for stirring. At this time, the stirring power of the high-speed mixer is 23kW. When the internal temperature of the high-speed mixer 211 reaches 40±2℃, 39kg of chain extender is added. The chain extender is a mixture of 1,2-propanediamine, ethylenediamine and DMAC, wherein the mass ratio of 1,2-propanediamine and ethylenediamine is 7:3, and the mass fraction of 1,2-propanediamine and ethylenediamine in the mixture is 7%. The viscosity of the liquid at the outlet of the high-speed mixer 211 is controlled at 2000±400 poise. Then, the solution in the high-speed mixer 211 is continuously pumped through a thin tube into the static tubular chain extender reactor 212 using a gear pump. After staying in the static tubular chain extender reactor 212 for 30 seconds, the viscosity of the material reaches 4000±200 poise. The polymer is then transported from the static tubular chain extender reactor 212 to the dynamic mixing reactor 221. At the same time, 10.35 kg of terminator is added to the dynamic mixing reactor 221 and stirred thoroughly. At this time, the stirring power of the dynamic mixing reactor is 11 kW. The terminator is a mixture of diethylamine and DMAC, in which diethylamine accounts for 7% of the mass fraction of the terminator mixture. The terminator is added over 30 seconds.

[0050] During the addition of the terminator, when the solution temperature reaches 50°C, cooling is achieved using refrigerant circulation in the jacket of the dynamic mixing reactor 221 to maintain the material temperature in the dynamic mixing reactor 221 at 45°C. The viscosity of the polymer in the dynamic mixing reactor 221 is monitored. When the polymer in the dynamic mixing reactor 221 reaches the target viscosity of 5000±200 poise, the polymer is transferred to the static tubular terminator reactor 222 and mixed statically for 20 minutes.

[0051] After static mixing, when the material viscosity reaches 6000±200 poise, 10.71 kg of additives are added simultaneously when the polymerization stock solution is transferred from the static tubular termination reactor 222 to the static tubular ADD mixer 402. The additives are a mixture of zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant, and DMAC solution in a mass fraction ratio of 180:50:30:20:450. After mixing for 150 minutes, the polyurethane stock solution is obtained. Actual measured parameters were recorded during the preparation process, as shown in Table 1.

[0052] After spinning the polyurethane raw material, the material properties of the spandex were tested. The obtained polyurethane elastic fiber sample was stretched to 100%, treated with hot air at 190℃ for 90 seconds, and the mechanical properties were tested using a tensile testing machine, as shown in Table 3.

[0053] Example 4 100 kg of poly(neopentyl adipate) glycol and 20 kg of 4,4'-diphenylmethane diisocyanate (MDI) were fed into the prepolymerization reactor 102. At this time, the mass ratio of the reactants poly(neopentyl adipate) glycol to 4,4'-diphenylmethane diisocyanate (MDI) was 5:1. Under stirring, the reaction temperature was controlled at 70±2℃. After reacting for 120 minutes, 180 kg of dimethylacetamide (DMAC) was added to the prepolymerization reactor 102 and stirred thoroughly. After the dimethylacetamide was added, the material was transferred to the prepolymer buffer tank 103. The prepolymer is sent from the prepolymer buffer tank 103 to the high-speed mixer 211 for stirring. At this time, the stirring power of the high-speed mixer is 30kW. When the internal temperature of the high-speed mixer 211 reaches 40±2℃, 23kg of chain extender is added. The chain extender is a mixture of 1,2-propanediamine, ethylenediamine and DMAC, wherein the mass ratio of 1,2-propanediamine and ethylenediamine is 8:2, and the mass fraction of 1,2-propanediamine and ethylenediamine in the mixture is 7%. The viscosity of the liquid at the outlet of the high-speed mixer 211 is controlled at 1500±400 poise. Then, the solution in the high-speed mixer 211 is continuously pumped through a thin tube into the static tubular chain extender reactor 212 using a gear pump. After staying in the static tubular chain extender reactor 212 for 30 seconds, the viscosity of the material reaches 3000±200 poise. The polymer is then transported from the static tubular chain extender reactor 212 to the dynamic mixing reactor 221. At the same time, 6.1 kg of terminator is added to the dynamic mixing reactor 221 and stirred thoroughly. At this time, the stirring power of the dynamic mixing reactor is 11 kW. The terminator is a mixture of diethylamine and DMAC, in which diethylamine accounts for 7% of the mass fraction of the terminator mixture. The terminator is added over 30 seconds.

[0054] During the addition of the terminator, when the solution temperature reaches 50°C, cooling is achieved using refrigerant circulation in the jacket of the dynamic mixing reactor 221 to maintain the material temperature in the dynamic mixing reactor 221 at 45°C. The viscosity of the polymer in the dynamic mixing reactor 221 is monitored. When the polymer in the dynamic mixing reactor 221 reaches the target viscosity of 3000±200 poise, the polymer is transferred to the static tubular terminator reactor 222 and mixed statically for 30 minutes.

[0055] After static mixing, when the material viscosity reaches 6000±200 poise, 10.11 kg of additives are added simultaneously when the polymerization stock solution is transferred from the static tubular termination reactor 222 to the static tubular ADD mixer 402. The additives are a mixture of zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant, and DMAC solution in a mass fraction ratio of 180:50:30:20:450. After mixing for 150 minutes, polyurethane stock solution is obtained.

[0056] During the preparation process, the actual measured parameters were recorded, as shown in Table 1.

[0057] After spinning the polyurethane raw material, the material properties of the spandex were tested. The obtained polyurethane elastic fiber sample was stretched to 100%, treated with hot air at 190℃ for 90 seconds, and the mechanical properties were tested using a tensile testing machine, as shown in Table 3.

[0058] Example 5 100 kg of poly(neopentyl adipate) glycol and 20 kg of 4,4'-diphenylmethane diisocyanate (MDI) were fed into the prepolymerization reactor 102. At this time, the mass ratio of the reactants poly(neopentyl adipate) glycol to 4,4'-diphenylmethane diisocyanate (MDI) was 5:1. Under stirring, the reaction temperature was controlled at 70±2℃. After reacting for 120 minutes, 180 kg of dimethylacetamide (DMAC) was added to the prepolymerization reactor 102 and stirred thoroughly. After the dimethylacetamide was added, the material was transferred to the prepolymer buffer tank 103. The prepolymer is sent from the prepolymer buffer tank 103 to the high-speed mixer 211 for stirring. At this time, the stirring power of the high-speed mixer is 40kW. When the internal temperature of the high-speed mixer 211 reaches 40±2℃, 23kg of chain extender is added. The chain extender is a mixture of 1,2-propanediamine, ethylenediamine and DMAC, wherein the mass ratio of 1,2-propanediamine and ethylenediamine is 8:2, and the mass fraction of 1,2-propanediamine and ethylenediamine in the mixture is 7%. The viscosity of the liquid at the outlet of the high-speed mixer 211 is controlled at 1200±300 poise. Then, the solution in the high-speed mixer 211 is continuously pumped through a thin tube into the static tubular chain extender reactor 212 using a gear pump. After staying in the static tubular chain extender reactor 212 for 30 seconds, the viscosity of the material reaches 3000±200 poise. The polymer is then transported from the static tubular chain extender reactor 212 to the dynamic mixing reactor 221. At the same time, 6.1 kg of terminator is added to the dynamic mixing reactor 221 and stirred thoroughly. At this time, the stirring power of the dynamic mixing reactor is 11 kW. The terminator is a mixture of diethylamine and DMAC, in which diethylamine accounts for 7% of the mass fraction of the terminator mixture. The terminator is added over 30 seconds.

[0059] During the addition of the terminator, when the solution temperature reaches 50°C, cooling is achieved using refrigerant circulation in the jacket of the dynamic mixing reactor 221 to maintain the material temperature in the dynamic mixing reactor 221 at 45°C. The viscosity of the polymer in the dynamic mixing reactor 221 is monitored. When the polymer in the dynamic mixing reactor 221 reaches the target viscosity of 3000±200 poise, the polymer is transferred to the static tubular terminator reactor 222 and mixed statically for 30 minutes.

[0060] After static mixing, when the material viscosity reaches 6000±200 poise, 10.11 kg of additives are added simultaneously when the polymerization stock solution is transferred from the static tubular termination reactor 222 to the static tubular ADD mixer 402. The additives are a mixture of zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant, and DMAC solution in a mass fraction ratio of 180:50:30:20:450. After mixing for 150 minutes, polyurethane stock solution is obtained.

[0061] During the preparation process, the actual measured parameters were recorded, as shown in Table 1.

[0062] After spinning the polyurethane raw material, the material properties of the spandex were tested. The obtained polyurethane elastic fiber sample was stretched to 100%, treated with hot air at 190℃ for 90 seconds, and the mechanical properties were tested using a tensile testing machine, as shown in Table 3.

[0063] Comparative Example 1 The difference between this comparative example and Example 1 is that the chain extension and termination reactions share a single high-speed mixing reactor, as detailed below: 100 kg of poly(neopentyl adipate) glycol and 20 kg of 4,4'-diphenylmethane diisocyanate (MDI) were fed into the prepolymerization reactor 102. At this time, the mass ratio of the reactants poly(neopentyl adipate) glycol to 4,4'-diphenylmethane diisocyanate (MDI) was 5:1. Under stirring, the reaction temperature was controlled at 70±2℃. After reacting for 120 minutes, 180 kg of dimethylacetamide (DMAC) was added to the prepolymerization reactor 102 and stirred thoroughly. After the dimethylacetamide was added, the material was transferred to the prepolymer buffer tank 103. The prepolymer is transferred from the prepolymer buffer tank 102 to the high-speed mixer 211 for stirring. The stirring power of the high-speed mixer is 40 kW. When the internal temperature of the high-speed mixer 211 reaches 40 ± 2 °C, 23 kg of chain extender is added. The chain extender is a mixture of 1,2-propanediamine, ethylenediamine, and DMAC, with a mass ratio of 8:2 and a mass fraction of 7%. When the viscosity of the liquid in the high-speed mixer 211 reaches 2000 ± 200 poise, 6.1 kg of terminator is added and stirred thoroughly. The stirring power of the high-speed mixer is 11 kW. The terminator is a mixture of diethylamine and DMAC, with diethylamine accounting for 7% of the mass fraction of the terminator mixture.

[0064] During the addition of the terminator, when the solution temperature reaches 50°C, cooling is achieved using refrigerant circulation in the jacket of the high-speed mixer 211 to maintain the material temperature in the high-speed mixer 211 at 45°C. The viscosity of the polymer inside the high-speed mixer 211 is monitored, and the reaction is terminated when the polymer inside the high-speed mixer 211 reaches the target viscosity of 3000±200 poise.

[0065] After the reaction is terminated, when the viscosity of the material reaches 6000±200 poise, the polymer is transferred from the high-speed mixer 211 to the static tubular ADD mixer 402. When transferring the polymer stock solution, 10.11 kg of additives are added simultaneously. The additives are a mixture of zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant, and DMAC solution in a mass fraction ratio of 180:50:30:20:450. After mixing for 150 minutes, the polyurethane stock solution is obtained.

[0066] During the preparation process, the actual measured parameters were recorded, as shown in Table 2.

[0067] After spinning the polyurethane raw material, the material properties of the spandex were tested. The obtained polyurethane elastic fiber sample was stretched to 100%, treated with hot air at 190℃ for 90 seconds, and the mechanical properties were tested using a tensile testing machine, as shown in Table 3.

[0068] Comparative Example 2: The difference between this comparative example and Example 1 is that the reactors used for the chain extension and termination reaction processes are two high-speed mixing reactors connected in series, as detailed below: 100 kg of poly(neopentyl adipate) glycol and 20 kg of 4,4'-diphenylmethane diisocyanate (MDI) were fed into the prepolymerization reactor 102. At this time, the mass ratio of the reactants poly(neopentyl adipate) glycol to 4,4'-diphenylmethane diisocyanate (MDI) was 5:1. Under stirring, the reaction temperature was controlled at 70±2℃. After reacting for 120 minutes, 180 kg of dimethylacetamide (DMAC) was added to the prepolymerization reactor 102 and stirred thoroughly. After the dimethylacetamide was added, the material was transferred to the prepolymer buffer tank 103. The prepolymer is transferred from the prepolymer buffer tank to a high-speed mixer 211 for stirring. The stirring power of the high-speed mixer is 40 kW. When the internal temperature of the high-speed mixer 211 reaches 40 ± 2 °C, 23 kg of chain extender is added. The chain extender is a mixture of 1,2-propanediamine, ethylenediamine, and DMAC, with a mass ratio of 8:2 and a mass fraction of 7%. When the viscosity of the liquid in the high-speed mixer 211 reaches 2000 ± 200 poise, the liquid is transferred to a dynamic mixing reactor 221, where 6.1 kg of terminator is added and stirred thoroughly. The stirring power of the dynamic mixing reactor is 11 kW. The terminator is a mixture of diethylamine and DMAC, with diethylamine accounting for 7% of the mass fraction of the terminator mixture. The terminator is added over 30 seconds.

[0069] During the addition of the terminator, when the solution temperature reaches 50°C, cooling is achieved through refrigerant circulation in the jacket of the dynamic mixing reactor 221, maintaining the material temperature in the dynamic mixing reactor 221 at 45°C. The viscosity of the polymer in the dynamic mixing reactor 221 is monitored, and the termination reaction process is completed when the polymer in the dynamic mixing reactor 221 reaches the target viscosity of 3000±200 poise.

[0070] After the reaction is terminated, when the viscosity of the material reaches 6000±200 poise, the polymer is transferred from the dynamic mixing reactor 221 to the static tubular ADD mixer 402. When transferring the polymer stock solution, 10.11 kg of additives are added simultaneously. The additives are a mixture of zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant, and DMAC solution in a mass fraction ratio of 180:50:30:20:450. After mixing for 150 minutes, the polyurethane stock solution is obtained.

[0071] During the preparation process, the actual measured parameters were recorded, as shown in Table 2.

[0072] After spinning the polyurethane raw material, the material properties of the spandex were tested. The obtained polyurethane elastic fiber sample was stretched to 100%, treated with hot air at 190℃ for 90 seconds, and the mechanical properties were tested using a tensile testing machine, as shown in Table 3.

[0073] Comparative Example 3: The difference between this comparative example and Example 1 is that the reactors used for the chain extension and termination reaction processes are two static tubular reactors connected in series, as detailed below: 100 kg of poly(neopentyl adipate) glycol and 20 kg of 4,4'-diphenylmethane diisocyanate (MDI) were fed into the prepolymerization reactor 102. At this time, the mass ratio of the reactants poly(neopentyl adipate) glycol to 4,4'-diphenylmethane diisocyanate (MDI) was 5:1. Under stirring, the reaction temperature was controlled at 70±2℃. After reacting for 120 minutes, 180 kg of dimethylacetamide (DMAC) was added to the prepolymerization reactor 102 and stirred thoroughly. After the dimethylacetamide was added, the material was transferred to the prepolymer buffer tank 103. The prepolymer is fed from the prepolymer buffer tank 102 into the static tubular chain extender reactor 212. The static tubular chain extender reactor has multiple feed ports and discharge ports spaced at intervals. When the internal temperature of the static tubular chain extender reactor reaches 40±2℃, 23kg of chain extender is added at the feed port. The chain extender is a mixture of 1,2-propanediamine, ethylenediamine, and DMAC, with a mass ratio of 8:2 and a mass fraction of 7%. When the viscosity of the liquid in the static tubular chain extender reactor 212 reaches 2000±200 poise, the liquid is transferred to the static tubular termination reactor 222, where 6.1kg of termination agent is added. The termination agent is a mixture of diethylamine and DMAC, with diethylamine accounting for 7% of the mass fraction of the termination agent mixture.

[0074] After the terminator is added, cooling is achieved by circulating refrigerant in the jacket of the static tubular termination reactor 222 to maintain the material temperature in the reactor at 45°C. The termination reaction is completed when the polymer in the static tubular termination reactor reaches the target viscosity of 3000±200 poise.

[0075] After the reaction is terminated, when the viscosity of the material reaches 6000±200 poise, the polymer is transferred to a static tubular ADD mixer. 10.11 kg of additives are added simultaneously when transferring the polymer stock solution. The additives are a mixture of zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant, and DMAC solution in a mass fraction ratio of 180:50:30:20:450. After mixing for 150 minutes, the polyurethane stock solution is obtained.

[0076] During the preparation process, the actual measured parameters were recorded, as shown in Table 2.

[0077] After spinning the polyurethane raw material, the material properties of the spandex were tested. The obtained polyurethane elastic fiber sample was stretched to 100%, treated with hot air at 190℃ for 90 seconds, and the mechanical properties were tested using a tensile testing machine, as shown in Table 3.

[0078] Table 1. Record of Actual Measurement Parameters for Chain Extension Process in Each Embodiment Table 2. Record of Actual Measured Parameters for Chain Extension Process in Comparative Examples 1 to 3 Table 3 Mechanical Properties of Polyurethane Elastic Fiber Samples Through Examples 1 to 5, it can be seen that this application adopts a semi-continuous polymerization process. In terms of equipment, a semi-continuous polymerization process is formed by setting up a high-speed mixing reactor, a static tubular chain extender reactor, a dynamic mixing reactor, and a static tubular termination reactor. Simultaneously, the chain extender and termination agent are added stepwise, making the polymerization process easier to control and solving the problem of inaccurate product viscosity control during the reaction. This allows for flexible adjustment of the intermittent prepolymerization reaction time and temperature, enabling precise control of the viscosity of the product after the chain extension reaction, and accommodating flexible replacement of various raw materials. Specifically, in Examples 4 and 5, the viscosity of the feed liquid at the outlet of the high-speed mixer in the chain extension reaction process is reduced to 1500±400 and 1200±300, respectively. The polymer in the dynamic mixing reactor at the termination reaction reaches the target viscosity by reducing it to 3000 poise. After the termination reaction, the curing time needs to be extended to reach the target viscosity. Furthermore, the polyurethane elastic fibers obtained in Examples 4 and 5 show reduced elongation at break.

[0079] As can be seen from Examples 1, 4, and 5, as the controlled viscosity of the polymer decreases, the fiber's breaking strength, elastic recovery rate at 300% elongation, and strength retention rate show a change of first increasing and then decreasing. This indicates that by controlling the viscosity of the material at different reaction stages, the properties of the final polymer elastic fiber can be controlled.

[0080] As can be seen from Examples 1, 1 Comparative Example, and 2, when achieving the same target viscosity, the stirring power of a semi-continuous polymerization process in which the chain extension and termination processes are set in different reactors is significantly lower than that of a process in which the chain extension and termination processes share a single high-speed mixing reactor, or a process in which the chain extension and termination processes use two high-speed mixing reactors connected in series.

[0081] As can be seen from Comparative Example 3, if the reactors used for the chain extension and termination reaction processes are simply two static tubular reactors connected in series, the viscosity of the polymer will be higher than the design target viscosity after the termination reaction is completed, which will not meet the design requirements and result in a lower elongation at break of the final product.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A semi-continuous polymerization process for producing multi-component copolymer polyurethane elastic fibers, comprising a prepolymerization step, a chain extension step, and a functional blending step, characterized in that, The raw materials used in the prepolymerization process include polydiols containing ether and ester bonds, and 4,4'-diphenylmethane diisocyanate, and the solvent used is DMAC; The chain extension process is divided into: chain extension reaction steps carried out sequentially in different reaction equipment and a termination reaction step; The chain extension reaction step is as follows: First, the prepolymer is mixed and stirred at high speed in a high-speed mixing reactor. When the temperature of the prepolymer reaches 40±2℃, a chain extender is added to the prepolymer. When the viscosity of the liquid at the outlet of the high-speed mixing reactor reaches 2000±400 poise, the chain extension reaction material is continuously fed into a static tubular chain extender reactor to continue the chain extender reaction. After the chain extension reaction material has fully reacted in the static tubular chain extender reactor, the reaction is terminated. The termination reaction step is as follows: the polymer in the static tubular chain extender reactor is transported to the dynamic mixing reactor, and a terminator is added to the dynamic mixing reactor at the same time. During the addition of the terminator, when the solution temperature reaches 50℃±2℃, the material temperature in the dynamic mixing reactor is maintained at 45℃±2℃ by circulating the refrigerant in the jacket of the dynamic mixing reactor. When the polymer in the dynamic mixing reactor reaches the target viscosity, the polymer is transferred to the static tubular termination reactor for thorough static mixing and formulation.

2. The semi-continuous polymerization production process for multi-component copolymer polyurethane elastic fibers as described in claim 1, characterized in that, The prepolymerization process specifically includes: Polydiols containing ether and ester bonds and 4,4'-diphenylmethane diisocyanate raw materials are fed into a prepolymerization reactor at a mass ratio of 5:1 to 4:

1. Under stirring, the reaction temperature is controlled at 68 to 72°C. After the reaction is complete, sufficient DMAC is added to the prepolymerization reactor. After stirring and adding, the material is transferred to a prepolymer buffer tank.

3. The semi-continuous polymerization production process for multi-component copolymer polyurethane elastic fibers as described in claim 1, characterized in that, The functional preparation process is as follows: when transferring the polymerization stock solution from the static tubular termination reactor to the static tubular ADD mixer, a mixed solution of zinc oxide, titanium dioxide, anti-yellowing agent, antioxidant additive and DMAC is added simultaneously. After thorough mixing, the stock solution is transferred to the polyurethane stock solution storage tank.

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