A method for recovering a polyamide acid effluent sample waste liquid

Abstract

The application discloses a kind of polyamide acid release sampling waste liquid recovery method.Method: the viscosity of the waste liquid collected together is adjusted by dianhydride solution, so that it is consistent with the viscosity of spinning dope, then the adjusted waste liquid is sent to spinning;The mass concentration and mass of the added dianhydride solution are calculated by the following formula: the required added dianhydride weight T=m*K* (n1*(C-c1)+n2(C-c2)+n3(C-c3)+n4(C-c4)+n5(C-c5)) / (1+C), the added solvent amount L=T*(1+C)*(1-K) / (C*K), the required configuration dianhydride solution mass concentration S=T / (T+L);The application accurately adjusts the viscosity of the collected waste liquid, so that it can continue to spin to realize the reutilization of release sampling waste liquid, can be used for industrialized continuous production to recover release sampling waste liquid in different stages, reduce the discharge of solid waste.

Description

Technical Field

[0001] This invention relates to the field of spinning technology, and in particular to a method for recovering waste liquid from polyamic acid effluent sampling. Background Technology

[0002] Polyamic acid, as a precursor solution for polyimide, requires multiple flaring and sampling for viscosity testing during industrial continuous production, from polymerization to spinning, to adjust the final viscosity and ensure production stability. Each flaring and sampling waste liquid is treated as solid waste after viscosity testing, and the raw solution also deteriorates after prolonged exposure to air. Each flaring and sampling involves more than 1 kg of raw solution, with each batch flaring and sampling around 5 kg. The viscosity, ratio, and concentration of the raw solution vary at different stages. Over time, this not only wastes raw materials but also poses additional risks for storage and disposal as solid waste. Even if collected, the varying states, viscosities, and concentrations of raw materials at different stages make unified recycling difficult. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned shortcomings of the prior art by proposing a method for collecting and recycling polyamic acid effluent samples from various stages.

[0004] The present invention provides a method for recovering polyamic acid effluent sampling waste liquid by adding a certain amount of dianhydride solution of mass concentration to adjust the viscosity of the collected effluent sampling waste liquid so that it is consistent with the viscosity of the spinning solution, and then the adjusted waste liquid is pumped into the spinning process.

[0005] The mass concentration and mass of the added dianhydride solution are calculated using the following formulas: Required dianhydride weight T = m*K*(n1*(C-c1)+n2(C-c2)+n3(C-c3)+n4(C-c4)+n5(C-c5)) / (1+C), Added solvent volume L = T*(1+C)*(1-K) / (C*K), Required dianhydride solution mass concentration S = T / (T+L);

[0006] Wherein, n1-n5 represent the number of times each effluent sampling is performed for the three polymerization stages and the two spinning stages; m represents the mass of each effluent sampling, and the mass of each effluent sampling is the same; K represents the mass concentration of the waste liquid sampled each time, which is assumed to be the same as the mass concentration of the spinning solution; c1-c5 represent the dianhydride ratio of the waste liquid sampled for each stage; and C represents the dianhydride ratio of the spinning solution.

[0007] Further, the specific operation for adjusting the viscosity of the effluent sampled waste liquid is as follows: a dianhydride solution with a mass concentration of S and a weight of T+L is added to the waste liquid in portions at a certain rate, and the mixture is stirred and reacted at a certain temperature for a period of time. A sample is taken to measure the viscosity. Then, a certain amount of dianhydride solution with a mass concentration of S is added again, and the mixture is stirred again. A sample is taken to measure the viscosity until the measured viscosity is consistent with the spinning solution. The mixture is then allowed to stand to remove bubbles.

[0008] Furthermore, the temperature of the waste liquid is controlled at 20-30℃, and the reaction is stirred for 2-4 hours.

[0009] Furthermore, the viscosity of the discharged waste liquid was adjusted, and the type of dianhydride added was consistent with the type of dianhydride in the spinning solution.

[0010] Furthermore, the solvent in the dianhydride solution is dimethylacetamide (DMAc).

[0011] Furthermore, the diamine monomer in the spinning solution is selected from one or more of 4,4-diaminodiphenyl ether (ODA), p-phenylenediamine (PDA), 4,4-diaminop-phenylmethane (MDA), hexamethylenediamine (HDA), and 3,5-diaminobenzoic acid (DABA).

[0012] Furthermore, the dianhydride monomer in the spinning solution is selected from one or more of pyromellitic dianhydride (PMDA), biphenyl dianhydride (BPDA), 4,4-diphenyl ether dianhydride (ODPA), and benzophenone tetracarboxylic dianhydride (BTDA).

[0013] This application achieves the recycling of effluent sampling wastewater by accurately adjusting the viscosity of the collected wastewater so that it can continue spinning. It can be used for industrial continuous production to recycle effluent sampling wastewater at different stages, thereby reducing solid waste emissions. Detailed Implementation

[0014] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0015] Example 1

[0016] A method for recovering polyamic acid effluent sampling waste liquid, comprising the following steps:

[0017] (1) Routing sampling: A 5L large-capacity plastic beaker is used for venting. The sampling valve is opened at the sampling port to start venting. When a certain amount is reached, a 200ml small-capacity sampling cup is used to sample and measure the viscosity. The large-capacity venting beaker can be used for venting at multiple sampling ports, including polymerization (3 times) and spinning process (2 times).

[0018] (2) Collection: After the viscosity of the sampled stock solution is measured, the sample and the discharge beaker are inverted and placed in the large-diameter funnel waste liquid collection device outside the recovery storage tank to allow it to flow into the storage tank. The funnel device with a lid is placed inside the discharge beaker and the sampling beaker and then the lid is tightly closed. After the stock solution has flowed out, the ball valve between the storage tank and the funnel is closed.

[0019] (3) Storage of recycled waste liquid: The recycling storage tank is supplied with 0.002 kg of protective nitrogen to prevent the recycled waste liquid from absorbing water and deteriorating upon contact with air; the storage tank jacket is supplied with 15℃ cold water to ensure that the temperature of the raw liquid is in a lower range, which is beneficial to the stability of the polyamic acid raw liquid.

[0020] (4) Viscosity adjustment: After collecting waste liquid for 15 days, when the liquid level in the storage tank is more than half full, adjust the stirring speed of the storage tank to 10 rpm, calculate the proportion and concentration ratio of waste liquid in each stage of recovery, prepare a dianhydride solution with a mass concentration of 11.8% (calculated), add it to the original liquid in the storage tank in batches at a certain rate, control the temperature at 30℃, stir and react for 4 hours, take a sample and measure the viscosity. When it is about 4000 poise (close to the viscosity of the original liquid), stop adding dianhydride and let it stand to remove bubbles.

[0021] Original solution parameters Sampling stage Number of samplings Waste liquid dianhydride ratio Sampling weight m 5kg Aggregation 1 11 0.2 stock solution concentration K 0.22 Aggregation 2 12 0.4 dianhydride ratio C in spinning solution 0.9 Aggregate 3 24 0.7 Required dianhydride weight T 10.71kg Spinning 1 10 0.9 Required solvent weight (L) 80.17kg Spinning 2 15 0.9

[0022] (5) Pressure feeding spinning: The raw liquid in the storage tank is evenly delivered to the spinning metering pump for subsequent continuous production by means of nitrogen pressure feeding and pump transportation.

[0023] The diamine monomer in the waste liquid mentioned above is 4,4-diaminodiphenyl ether (ODA). The dianhydride monomer is pyromellitic dianhydride (PMDA). The solvent is dimethylacetamide (DMAc). The stock solution has a mass concentration of 22% and a viscosity of 4000 poise.

[0024] Example 2

[0025] A method for recovering polyamic acid effluent sampling waste liquid, comprising the following steps:

[0026] (1) Routing sampling: A 5L large-capacity plastic beaker is used for venting. The sampling valve is opened at the sampling port to start venting. When a certain amount is reached, a 200ml small-capacity sampling cup is used to sample and measure the viscosity. The large-capacity venting beaker can be used for venting at multiple sampling ports, including polymerization (3 times) and spinning process (2 times).

[0027] (2) Collection: After the viscosity of the sampled stock solution is measured, the sample and the discharge beaker are inverted and placed in the large-diameter funnel waste liquid collection device outside the recovery storage tank to allow it to flow into the storage tank. The funnel device with a lid is placed inside the discharge beaker and the sampling beaker and then the lid is tightly closed. After the stock solution has flowed out, the ball valve between the storage tank and the funnel is closed.

[0028] (3) Storage of recycled waste liquid: The recycling storage tank is supplied with 0.002 kg of protective nitrogen to prevent the recycled waste liquid from absorbing water and deteriorating upon contact with air; the storage tank jacket is supplied with 20°C cold water to ensure that the temperature of the raw liquid is kept in a low range, which is beneficial to the stability of the polyamic acid raw liquid.

[0029] (4) Viscosity adjustment: After collecting waste liquid for 20 days, when the liquid level in the storage tank is more than half full, adjust the stirring speed of the storage tank to 15 rpm, calculate the proportion and concentration ratio of waste liquid in each stage of recovery, prepare a dianhydride solution with a mass concentration of 13.5% (calculated), add it to the original liquid in the storage tank in batches at a certain rate, control the temperature at 25℃, stir and react for 3 hours, take a sample and measure the viscosity. When it is about 5000 poise (close to the viscosity of the original liquid), stop adding dianhydride and let it stand to remove bubbles.

[0030] Original solution parameters Sampling stage Number of samplings Waste liquid dianhydride ratio Sampling weight m 5kg Aggregation 1 10 0.3 stock solution concentration K 0.26 Aggregation 2 15 0.5 dianhydride ratio C in spinning solution 0.8 Aggregate 3 15 0.6 Required dianhydride weight T 9.03kg Spinning 1 20 0.8 Required solvent weight (L) 57.8kg Spinning 2 20 0.8

[0031] (5) Pressure feeding spinning: The raw liquid in the storage tank is evenly delivered to the spinning metering pump for subsequent continuous production by means of nitrogen pressure feeding and pump transportation.

[0032] The diamine monomer in the waste liquid mentioned in the above steps is hexamethylenediamine (HDA). The dianhydride monomer is pyromellitic dianhydride (PMDA). The solvent is dimethylacetamide (DMAc). The stock solution concentration is 26%, and the stock solution viscosity is 5000 poise.

[0033] Example 3

[0034] A method for recovering polyamic acid effluent sampling waste liquid, comprising the following steps:

[0035] (1) Routing sampling: Routing is carried out using a 5L large-capacity plastic beaker. Open the sampling valve at the sampling port to start venting. When a certain amount is reached, use a 200ml small-capacity sampling cup to take a sample and measure the viscosity. The large-capacity venting beaker can be used for venting at multiple sampling ports, including polymerization (4 times) and spinning process (1 time).

[0036] (2) Collection: After the viscosity of the sampled stock solution is measured, the sample and the discharge beaker are inverted and placed in the large-diameter funnel waste liquid collection device outside the recovery storage tank to allow it to flow into the storage tank. The funnel device with a lid is placed inside the discharge beaker and the sampling beaker and then the lid is tightly closed. After the stock solution has flowed out, the ball valve between the storage tank and the funnel is closed.

[0037] (3) Storage of recycled waste liquid: The recycling storage tank is supplied with 0.002 kg of protective nitrogen to prevent the recycled waste liquid from absorbing water and deteriorating upon contact with air; the storage tank jacket is supplied with 20°C cold water to ensure that the temperature of the raw liquid is kept in a low range, which is beneficial to the stability of the polyamic acid raw liquid.

[0038] (4) Viscosity adjustment: After collecting waste liquid for 10 days, when the liquid level in the storage tank is more than half full, adjust the stirring speed of the storage tank to 20 rpm, calculate the proportion and concentration ratio of waste liquid in each stage of recovery, prepare a dianhydride solution with a mass concentration of 9.8% (calculated), add it to the original liquid in the storage tank in batches at a certain rate, control the temperature at 25℃, stir and react for 4 hours, take a sample to measure the viscosity, when it is about 3000 poise (close to the viscosity of the original liquid), stop adding dianhydride, and let it stand to degas.

[0039] Original solution parameters Sampling stage Number of samplings Waste liquid dianhydride ratio Sampling weight m 5kg Aggregation 1 11 0.3 stock solution concentration K 0.18 Aggregation 2 12 0.5 dianhydride ratio C in spinning solution 1 Aggregate 3 24 0.7 Required dianhydride weight T 9.86kg Spinning 1 10 0.9 Required solvent weight (L) 89.79kg Spinning 2 15 1.0

[0040] (5) Pressure feeding spinning: The raw liquid in the storage tank is evenly delivered to the spinning metering pump for subsequent continuous production by means of nitrogen pressure feeding and pump transportation.

[0041] The diamine monomer in the waste liquid mentioned above is 4,4-diaminodiphenyl ether (ODA). The dianhydride monomers are pyromellitic dianhydride (PMDA) and 4,4-diphenyl ether dianhydride (ODPA) in a molar ratio of 7:3. The solvent is dimethylacetamide (DMAc). The stock solution concentration is 18%, and the stock solution viscosity is 3000 poise.

[0042] Example 4

[0043] A method for recovering polyamic acid effluent sampling waste liquid, comprising the following steps:

[0044] (1) Routing sampling: Routing is carried out using a 5L large-capacity plastic beaker. Open the sampling valve at the sampling port to start venting. When a certain amount is reached, use a 200ml small-capacity sampling cup to take a sample and measure the viscosity. The large-capacity venting beaker can be used for venting at multiple sampling ports, including polymerization (4 times) and spinning process (1 time).

[0045] (2) Collection: After the viscosity of the sampled stock solution is measured, the sample and the discharge beaker are inverted and placed in the large-diameter funnel waste liquid collection device outside the recovery storage tank to allow it to flow into the storage tank. The funnel device with a lid is placed inside the discharge beaker and the sampling beaker and then the lid is tightly closed. After the stock solution has flowed out, the ball valve between the storage tank and the funnel is closed.

[0046] (3) Storage of recycled waste liquid: The recycling storage tank is supplied with 0.002 kg of protective nitrogen to prevent the recycled waste liquid from absorbing water and deteriorating upon contact with air; the storage tank jacket is supplied with 15℃ cold water to ensure that the temperature of the raw liquid is in a lower range, which is beneficial to the stability of the polyamic acid raw liquid.

[0047] (4) Viscosity adjustment: After collecting waste liquid for 20 days, when the liquid level in the storage tank is more than half, adjust the stirring speed of the storage tank to 15 rpm, calculate the proportion and concentration ratio of waste liquid in each stage of recovery, prepare a dianhydride solution with a mass concentration of 12.9% (calculated), add it to the original liquid in the storage tank in batches at a certain rate, control the temperature at 25℃, stir and react for 3 hours, take a sample and measure the viscosity. When it is about 4500 poise (close to the viscosity of the original liquid), stop adding dianhydride and let it stand to remove bubbles.

[0048]

[0049]

[0050] (5) Pressure feeding spinning: The raw liquid in the storage tank is evenly delivered to the spinning metering pump for subsequent continuous production by means of nitrogen pressure feeding and pump transportation.

[0051] The waste liquid diamine monomers mentioned in the above steps are 4,4-diaminodiphenyl ether (ODA) and hexamethylenediamine (HDA) in a molar ratio of 5:5. The dianhydride monomer is pyromellitic dianhydride (PMDA). The solvent is dimethylacetamide (DMAc). The stock solution concentration is 23%, and the stock solution viscosity is 4500 poise.

[0052] The following table compares the performance indicators of the recovered and formulated spinning solution and the conventional dosing solution after spinning, cyclization, and drawing in the above embodiments:

[0053]

[0054] As can be seen from the table above, the product indicators obtained after spinning treatment of the recycled waste liquid and the normal raw liquid are basically the same, both meeting the prescribed testing standards and satisfying the requirements for subsequent use.

[0055] For any points not covered above, existing technologies shall apply.

[0056] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for recovering a polyamic acid discharge sampling waste solution, characterized by, The viscosity of the waste liquid collected together is adjusted by adding a certain amount of dianhydride solution with a certain mass concentration, so as to be consistent with the viscosity of the spinning dope, and then the adjusted waste liquid is sent to spinning; The mass concentration and mass of the added dianhydride solution are calculated by the following formula: the required added dianhydride weight T = m * K * (n1 * (C-c1) + n2 * (C-c2) + n3 * (C-c3) + n4 * (C-c4) + n5 * (C-c5)) / (1+C), the added solvent amount L = T * (1+C) * (1-K) / (C * K), and the required mass concentration S of the configured dianhydride solution = T / (T+L); Wherein, n1-n5 are the number of secondary bleed sampling for three stages of polymerization and two stages of spinning respectively; m is the mass of each bleed sampling, and the mass of each bleed sampling is the same; K is the mass concentration of the waste liquid of each sampling, which is the same as the mass concentration of the spinning dope by default here; c1-c5 are the dianhydride ratio of the waste liquid of each stage sampling; C is the dianhydride ratio of the spinning dope; The type of dianhydride added to adjust the viscosity of the waste liquid of the bleed sampling is consistent with the type of dianhydride of the spinning dope.

2. The method of claim 1, wherein the polyamic acid discharged sample waste solution is recovered by, The specific operation of adjusting the viscosity of the waste liquid of the bleed sampling is as follows: a dianhydride solution with a mass concentration S and a weight of T+L is added to the waste liquid in several times at a certain rate, stirred for a period of time at a certain temperature, sampled and measured for viscosity, then a certain amount of dianhydride solution with a mass concentration S is continuously added, continuously stirred, sampled and measured for viscosity, until the measured viscosity is consistent with the spinning dope, and then defoaming is performed.

3. The recovery method of a polyamic acid discharged sample waste solution according to claim 2, characterized by, The temperature of the waste liquid is controlled at 20-30℃, and the stirring reaction is performed for 2-4h.

4. The method of claim 1, wherein the polyamic acid discharged sample waste solution is recovered by, The solvent in the dianhydride solution is dimethylacetamide DMAc.

5. The method for recovering polyamic acid effluent sampling waste liquid as described in claim 1, characterized in that, The diamine monomer of the spinning dope is selected from one or more of 4,4-diaminodiphenyl ether ODA, p-phenylenediamine PDA, 4,4-diaminomethyl benzene MDA, hexanediamine HDA, and 3,5-diaminobenzoic acid DABA.

6. The method of claim 1, wherein the polyamic acid discharged sample waste solution is recovered by, The dianhydride monomer of the spinning dope is selected from one or more of pyromellitic dianhydride PMDA, biphenyl tetracarboxylic dianhydride BPDA, 4,4-biphenyl ether dianhydride ODPA, and benzophenone tetracarboxylic dianhydride BTDA.

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