A production process of spandex bonding agent

Abstract

The invention discloses a production process of a spandex cohesive agent, which comprises the following steps: mixing isooctyl alcohol, maleic anhydride and p-toluenesulfonic acid, carrying out an esterification reaction under reduced pressure distillation, adding a saturated Na2CO3 aqueous solution after the reaction is completed, and adjusting the pH; then adding NaHSO3, AOT and water for sulfonation reaction, adding an azeotropic agent after the reaction is completed, heating to a temperature for azeotropy with water, and removing water; adding a certain amount of DMAC after the removal of water, and recovering the azeotropic agent by atmospheric distillation; adding DMAC and a filter aid to crude sodium succinate sulfonate, filtering, and obtaining a DMAC solution of sodium succinate sulfonate with a mass concentration of 35%, which is the spandex cohesive agent. The process of the invention can directly produce a spandex cohesive agent product, which not only avoids the generation of a large amount of wastewater, but also realizes the recyclable utilization of the solvent, simplifies the process, reduces energy consumption and production costs, and solves the environmental pollution problem caused by traditional processes.

Description

Technical Field

[0001] The invention belongs to the field of auxiliary agent synthesis in fiber processing technology, and particularly relates to a production process of a spandex cohesive agent. Background Art

[0002] Spandex bonding agent is a functional additive that needs to be added in the production process of high-temperature resistant spandex yarn to improve the bonding performance and strength of spandex yarn. Its main component is generally dimethylacetamide (DMAC) solution of sodium diisooctyl sulfosuccinate (AOT).

[0003] At present, the dimethylacetamide (DMAC) solution of sodium diisooctyl sulfosuccinate (AOT) is prepared by preparing the commercially available AOT product, namely the ethanol and water solution of AOT (the commercially available AOT product cannot be directly used as a spandex bonding agent). The specific preparation steps are: first, the commercially available AOT ethanol and water solution is dried, then methanol solution is added to completely dissolve it, and the sulfate precipitate is filtered out. After repeated drying, dissolving and filtering operations, the methanol is evaporated to remove the methanol; then DMAC is added to dissolve, and the sulfate precipitate is filtered out to finally obtain the spandex bonding agent-OT35 (i.e., the DMAC solution of AOT).

[0004] The commercially available sodium diisooctyl sulfosuccinate (AOT) products are mostly ethanol and aqueous solutions of AOT, with a solid content of about 70%. The synthetic process route is shown in Figure 2 shown; reference Figure 3 The production steps are as follows: (1) maleic anhydride, isooctyl alcohol and p-toluenesulfonic acid are added to a reaction kettle under nitrogen protection, and then stirred at 90°C for 10 minutes. When there is no maleic anhydride solid in the reaction system, the temperature is raised to 120°C and heated to reflux. The water generated by the reaction is removed by an oil-water separator under reduced pressure (5.33 KPa) of a water pump. The reaction is continued for 3 hours, and the heating is stopped. The mixture is cooled to room temperature, and washed and extracted with a saturated sodium carbonate solution for multiple times. The aqueous phase is discarded, and anhydrous Mg2SO4 is added to the organic phase for drying and filtering to obtain diisooctyl succinate.

[0005] (2) Under nitrogen protection, add diisooctyl succinate, phase transfer catalyst AOT, NaHSO3, and deionized water into a reactor, stir vigorously, and keep the reaction at 130°C for 4 hours. A large amount of solid will be generated in the bottle. After the reaction is completed, cool to 60°C, add ethanol and activated carbon, stir to dissolve, and after the white solid is completely dissolved, reduce the pressure and filter while hot to obtain a white solution of sodium diisooctyl sulfosuccinate in ethanol and water.

[0006] (3) The ethanol and water solution of sodium diisooctyl sulfonate succinate was evaporated at 200°C to dry the ethanol and water to obtain dry sodium diisooctyl sulfonate succinate solid; the sodium diisooctyl sulfonate succinate solid was dissolved in methanol, filtered to remove inorganic salts, and the methanol was completely evaporated at 200°C to obtain pure sodium diisooctyl sulfonate succinate; finally, the sodium diisooctyl sulfonate succinate solid was dissolved in DMAC, during which a small amount of inorganic salts would precipitate, which needed to be filtered again, and finally a sodium diisooctyl sulfonate succinate DMAC solution with a concentration of 35% was prepared.

[0007] In the above process of producing spandex bonding agent, there are the following problems:

[0008] (1) In the process of producing commercially available AOT products, the neutralization and extraction operations with saturated sodium carbonate solution during the post-esterification reaction will generate a large amount of wastewater. The wastewater generated has high treatment costs in the industry and is very harmful to the environment.

[0009] (2) In the process of producing commercially available AOT products, the solvents used cannot be directly recycled, resulting in serious waste. In addition, the recycling process consumes a lot of energy, which increases production costs.

[0010] (3) In the process of producing commercially available AOT products, there are a large number of inorganic salts (such as Na2SO4, NaHSO3 and Na2SO3, etc.), which cannot be used directly in the process of spandex fiber bonding. If used directly, it will cause the spandex fiber to break and fail to achieve the purpose of fiber bonding.

[0011] (4) In the process of preparing commercially available AOT products into spandex bonding agents, the commercially available AOT products need to be dried, dissolved and filtered multiple times, resulting in large solvent loss and high energy consumption, which increases production costs and causes environmental problems such as waste gas and wastewater emissions. Summary of the invention

[0012] In view of the above problems existing in the prior art, the purpose of the present invention is to provide a production process of a spandex cohesive agent.

[0013] In order to achieve the above object, the present invention adopts the following technical solutions:

[0014] A production process of a spandex cohesive agent comprises the following steps:

[0015] S1, esterification reaction: isooctyl alcohol, maleic anhydride and p-toluenesulfonic acid are mixed, preheated and pre-reacted, and then heated and esterified under reduced pressure distillation;

[0016] S2, sulfonation reaction: add saturated Na2CO3 aqueous solution to the reaction system after the esterification reaction in step S1 to adjust the pH to 7-8.4 to obtain a crude product of diisooctyl succinate; add NaHSO3, phase transfer catalyst AOT and distilled water to the neutralized reaction system, increase the temperature, and carry out sulfonation reaction;

[0017] S3, azeotropic dehydration: adding an azeotropic agent to the reaction system after the sulfonation reaction in step S3, heating until the azeotropic agent and water produce azeotropy, and removing water;

[0018] S4, recovering the entrainer: adding a certain amount of DMAC to the reaction system after dehydration, heating, distilling at normal pressure, distilling out the entrainer in the reaction system and recovering it to obtain crude sodium sulfosuccinate;

[0019] S5. Preparation of spandex bonding agent: Add DMAC and filter aid to crude sodium succinate sulfonate, filter, and obtain a DMAC solution of sodium succinate sulfonate with a mass concentration of 35%, which is the spandex bonding agent.

[0020] Preferably, in step S1, maleic anhydride, isooctyl alcohol and p-toluenesulfonic acid are mixed, preheated and pre-reacted, then heated, and esterification reaction is carried out under reduced pressure distillation. The specific steps are: maleic anhydride, isooctyl alcohol and p-toluenesulfonic acid are mixed, preheated to 75-85°C, pre-reacted for 0.5-3.0h, then heated to 110-125°C, and maintained under reduced pressure distillation for esterification reaction for 2-3.5h; wherein the vacuum degree under reduced pressure distillation is -0.01~-0.2Mpa, and the molar ratio of maleic anhydride, isooctyl alcohol and p-toluenesulfonic acid is 1:2-2.55:0.01-0.1.

[0021] Preferably, in step S1, a water separator is used to separate the distilled water and isooctyl alcohol during the esterification reaction, the isooctyl alcohol is used in the next esterification reaction, and the water participates in the sulfonation reaction in the next step S2.

[0022] Preferably, in step S2, the temperature of the sulfonation reaction is 120-140°C, the time of the sulfonation reaction is 3-6h; the molar ratio of diisooctyl succinate to NaHSO3 is 1:1-1.5, the mass ratio of the phase transfer catalyst AOT to diisooctyl succinate is 2-15:100, and the mass ratio of distilled water to NaHSO3 is 1.35-2.0:1.

[0023] Preferably, in step S3, the water content of the system after the water removal treatment is less than 0.2%, the amount of the entrainer added is the same as the theoretical mass of the spandex cohesive agent, and the entrainer is any one of toluene, ethyl acetate, cyclohexane, chloroform and n-hexane.

[0024] Preferably, in step S3, the distilled water and the entrainer are separated by a condensation water separator during the azeotropic dehydration process, and the separated entrainer flows back into the reaction system to maintain the fluidity of the system, and the water is recovered and continues to participate in the sulfonation reaction of step S2.

[0025] Preferably, in step S4, the ratio of the amount of DMAC added to the theoretical mass of the spandex cohesive agent is 20-40:100; the purpose of adding a certain amount of DMAC in this step is to remove the entrainer in the reaction system by atmospheric distillation on the one hand, and to maintain the fluidity of the system after the entrainer is removed on the other hand.

[0026] Preferably, in step S5, the filter aid has both a filtering effect and a decolorizing effect, and the ratio of the added amount of the filter aid to the theoretical mass of the spandex bonding agent is 0.01-1:100; the filter aid is any one of white active soil, activated carbon, cellulose and perlite, and perlite is further preferred.

[0027] The present invention has the following beneficial effects:

[0028] (1) After the esterification reaction is completed, the present invention uses a saturated sodium carbonate aqueous solution to neutralize the reaction solution, and directly uses the reaction solution as the next step material for sulfonation reaction without separation of the organic phase and the aqueous phase, thereby omitting the steps of separating oil from water after neutralizing the esterification reaction solution with a saturated sodium carbonate aqueous solution, and then washing the oil phase with water for multiple times and filtering to remove inorganic salts, thereby avoiding the generation of a large amount of wastewater;

[0029] (2) In the prior art, after the sulfonation reaction is completed (the viscosity of the reaction liquid is too high at this time), an AOT product can be produced by adding a solvent such as methanol or ethanol (without separation and purification). However, the AOT product cannot be directly used as a spandex bonding agent. This is mainly because too much inorganic salt (mostly sodium sulfate, sodium sulfite, sodium bisulfite, etc.) will remain in the sulfonation reaction process, and the presence of too much inorganic salt will cause spandex yarn breakage. However, in the present invention, after the sulfonation reaction is completed, an entrainer is added to remove water in the reaction system (the removed water can be repeatedly involved in the production), so that the inorganic salts (mostly sodium sulfate, sodium sulfite, sodium bisulfite, etc., which are difficult to dissolve in DMAC) generated in the reaction system can be fully separated out. Then, by utilizing the insolubility of the above-mentioned inorganic salts in DMAC, a certain amount of DMAC is added to distill and recover (remove) the entrainer, and the inorganic salts are separated by filtration, so that a high-purity (effective ingredient is above 99.8%, up to 99.9%) spandex bonding agent that meets the standards can be obtained.

[0030] The invention can directly produce a spandex bonding agent by optimizing the process and parameters, can avoid the generation of a large amount of waste water, realize the recycling of the solvent, reduce the subsequent processing steps, simplify the process, and greatly reduce energy consumption, production costs and environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A production process roadmap of a spandex bonding agent provided by the present invention;

[0033] Figure 2 The synthetic process route diagram of the commercially available sodium diisooctyl sulfosuccinate product;

[0034] Figure 3 The present invention is a process flow chart of the production steps of existing spandex bonding agents. DETAILED DESCRIPTION

[0035] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are provided to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may also be implemented in other embodiments without these specific details.

[0036] Example 1

[0037] Reference Figure 1 , a production process of a spandex cohesive agent, comprising the following steps:

[0038] S1. Esterification reaction: isooctyl alcohol (IS), maleic anhydride (MA) and p-toluenesulfonic acid (TsOH) are added to a 250 mL reactor in sequence according to a molar ratio of 2.27:1:0.02, and the temperature is raised to 80°C for preheating to completely dissolve the solid in the reaction system, and the pre-reaction is maintained at normal pressure for 1 hour; then the temperature is raised to 110°C, and the vacuum degree in the reactor is controlled at -0.06Mpa by a vacuum pump to carry out the esterification reaction, and at the same time, the distilled water and isooctyl alcohol are separated by a water separator, and the isooctyl alcohol is recovered for use in the next esterification reaction. During the esterification reaction, the acid value is measured every 0.5 hour and the esterification rate is calculated. When the esterification rate reaches more than 98%, the reaction is stopped;

[0039] S2, sulfonation reaction: add saturated Na2CO3 aqueous solution to the reaction system after the esterification reaction in step S1, neutralize the reaction product in the system to pH 7.5, and obtain a crude product of diisooctyl succinate; add NaHSO3, phase transfer catalyst AOT and distilled water to the neutralized reaction system, heat to 120°C, maintain the sulfonation reaction for 3 hours, and use a condenser to condense the water vapor generated during the reaction into water and then flow back into the reactor to keep the system fluid. During the sulfonation reaction, sample and measure the iodine value every 0.5 hours, calculate the sulfonation rate, and stop the reaction when the sulfonation rate reaches more than 98%, wherein the molar ratio of diisooctyl succinate to NaHSO3 is 1:1.5, the mass ratio of phase transfer catalyst AOT to diisooctyl succinate is 9:100, and the mass ratio of distilled water to NaHSO3 is 2.0:1;

[0040] S3, azeotropic dehydration: add cyclohexane to the reaction system after the sulfonation reaction is completed, the amount of cyclohexane added is the same as the theoretical mass of the spandex bonding agent, stir to completely dissolve the sulfonated product, heat to 65°C, make cyclohexane and water azeotropically remove water, and use a condensation water separator to separate the distilled water and cyclohexane, and the separated cyclohexane flows back to the reactor to keep the system fluidity, and continue to participate in the sulfonation reaction of step S2 after water recovery. When the water content is lower than 0.2wt%, stop heating, let it stand and cool, precipitate solid (inorganic salt), filter, and obtain filtrate;

[0041] S4, recovering the entrainer: transferring the obtained filtrate to a reactor, then adding a small amount of DMAC to maintain the fluidity inside the reaction system, heating to 88°C, distilling out the cyclohexane in the reactor under normal pressure and recovering it, and obtaining crude sodium succinate sulfonate (LDSS), wherein the ratio of the added amount of DMAC to the theoretical mass of the spandex cohesive agent is 35:100;

[0042] S5. Preparation of spandex bonding agent: DMAC was added to crude sodium succinate sulfonate to dissolve it, and then perlite was added and stirred for decolorization. The ratio of the amount of perlite added to the theoretical mass of the spandex bonding agent was 0.8:100. The solution was allowed to stand and filtered to obtain a DMAC solution of sodium succinate sulfonate with a mass concentration of 35%, which was the spandex bonding agent, i.e., spandex bonding agent-OT35 product, recorded as E1.

[0043] Example 2

[0044] S1. Esterification reaction: add isooctyl alcohol (IS), maleic anhydride (MA) and p-toluenesulfonic acid (TsOH) into a 250mL reactor in a molar ratio of 2.54:1:0.05, heat to 78°C for preheating, dissolve the solid in the reaction system completely, and keep the pre-reaction at normal pressure for 1h; then heat to 115°C, control the vacuum degree in the reactor at -0.08Mpa by a vacuum pump, and carry out esterification reaction. At the same time, use a water separator to separate the distilled water and isooctyl alcohol, and the isooctyl alcohol is recovered for the next esterification reaction. During the esterification reaction, the acid value is measured every 0.5h and the esterification rate is calculated. When the esterification rate reaches more than 98%, the reaction is stopped;

[0045] S2, sulfonation reaction: This step is the same as in Example 1;

[0046] S3, azeotropic dehydration: add toluene to the reaction system after the sulfonation reaction is completed, the amount of toluene added is the same as the theoretical mass of the spandex bonding agent, stir to completely dissolve the sulfonated product, heat to 95°C, make toluene and water azeotropically remove water, and use a condensation water separator to separate the distilled water and toluene, and the separated toluene flows back into the reactor to keep the system fluidity, and continue to participate in the sulfonation reaction of step S2 after water recovery, stop heating when the water content is lower than 0.1wt%, let stand and cool, precipitate solid (inorganic salt), filter to obtain filtrate;

[0047] S4, recovering the entrainer: transferring the obtained filtrate to a reactor, then adding a small amount of DMAC to maintain the fluidity inside the reaction system, heating to 118° C., distilling out the toluene in the reactor under normal pressure and recovering it, and obtaining crude sodium succinate sulfonate (LDSS), wherein the ratio of the added amount of DMAC to the theoretical mass of the spandex cohesive agent is 20:100;

[0048] S5. Preparation of spandex bonding agent: DMAC is added to crude sodium succinate sulfonate to dissolve, and then perlite is added and stirred. The ratio of the amount of perlite added to the theoretical mass of the spandex bonding agent is 0.1:100. The solution is allowed to stand and filtered to obtain a DMAC solution of sodium succinate sulfonate with a mass concentration of 35%, which is the spandex bonding agent, i.e., spandex bonding agent-OT35 product, recorded as E2.

[0049] Example 3

[0050] S1. Esterification reaction: add isooctyl alcohol (IS), maleic anhydride (MA) and p-toluenesulfonic acid (TsOH) into a 250mL reactor in a molar ratio of 2.35:1:0.03, heat to 75°C for preheating, dissolve the solid in the reaction system completely, and keep the pre-reaction at normal pressure for 1h; then heat to 115°C, control the vacuum degree in the reactor at -0.1Mpa by a vacuum pump, and carry out esterification reaction. At the same time, use a water separator to separate the distilled water and isooctyl alcohol, and the isooctyl alcohol is recovered for the next esterification reaction. During the esterification reaction, the acid value is measured every 0.5h and the esterification rate is calculated. When the esterification rate reaches more than 98%, the reaction is stopped;

[0051] S2, sulfonation reaction: This step is the same as in Example 1;

[0052] S3, azeotropic dehydration: add ethyl acetate to the reaction system after the sulfonation reaction is completed, stir to completely dissolve the sulfonation product, heat to 75°C, make ethyl acetate and water azeotropically remove water, and use a condensation water separator to separate the distilled water and ethyl acetate, and the separated ethyl acetate flows back into the reactor to keep the system fluidity, and the water is recovered and continues to participate in the sulfonation reaction of step S2. When the water content is lower than 0.2wt%, stop heating, let it stand and cool, precipitate solid (inorganic salt), filter, and obtain a filtrate;

[0053] S4, recovering the entrainer: transferring the obtained filtrate to a reactor, then adding a small amount of DMAC to maintain the fluidity inside the reaction system, heating to 80° C., distilling out the ethyl acetate in the reactor under normal pressure and recovering it, and obtaining crude sodium succinate sulfonate (LDSS), wherein the ratio of the amount of DMAC added to the theoretical mass of the spandex cohesive agent is 35:100;

[0054] S5, preparing a spandex cohesive agent: This step is the same as that in Example 1, and a DMAC solution of sodium sulfosuccinate having a mass concentration of 35% is obtained, which is a spandex cohesive agent, namely a spandex cohesive agent-OT35 product, recorded as E3.

[0055] Example 4

[0056] S1. Esterification reaction: add isooctyl alcohol (IS), maleic anhydride (MA) and p-toluenesulfonic acid (TsOH) into a 250mL reactor in a molar ratio of 2.55:1:0.1, heat to 80°C for preheating, dissolve the solid in the reaction system completely, and keep the pre-reaction at normal pressure for 2h; then heat to 120°C, control the vacuum degree in the reactor at -0.2Mpa by a vacuum pump, and carry out esterification reaction. At the same time, use a water separator to separate the distilled water and isooctyl alcohol, and the isooctyl alcohol is recovered for the next esterification reaction. During the esterification reaction, the acid value is measured every 0.5h and the esterification rate is calculated. When the esterification rate reaches more than 98%, the reaction is stopped;

[0057] S2, sulfonation reaction: add saturated Na2CO3 aqueous solution to the reaction system after the esterification reaction in step S1, neutralize the reaction product in the system to pH 8, and obtain a crude product of diisooctyl succinate; the experimental conditions are the same as those in Example 1;

[0058] S3, water removal treatment: add chloroform to the reaction system after the sulfonation reaction is completed, stir to completely dissolve the sulfonation product, heat to 62 ° C, make chloroform and water azeotropically remove water, and use a condensation water separator to separate the distilled water and chloroform, and the separated chloroform flows back into the reaction kettle to keep the system fluidity, and continue to participate in the sulfonation reaction of step S2 after water recovery. When the water content is less than 0.1wt%, stop heating, let it stand and cool, precipitate solid (inorganic salt), filter, and obtain a filtrate;

[0059] S4, recovering the entrainer: transferring the obtained filtrate to a reactor, then adding a small amount of DMAC to maintain the fluidity inside the reaction system, heating to 70°C, distilling out the chloroform in the reactor under normal pressure and recovering it, and obtaining crude sodium succinate sulfonate (LDSS), wherein the ratio of the added amount of DMAC to the theoretical mass of the spandex cohesive agent is 40:100;

[0060] S5. Preparation of spandex bonding agent: This step is basically the same as Example 1, except that perlite is replaced with activated carbon to obtain a spandex bonding agent-OT35 product, which is recorded as E4.

[0061] Example 5

[0062] S1. Esterification reaction: add isooctyl alcohol (IS), maleic anhydride (MA) and p-toluenesulfonic acid (TsOH) into a 250mL reactor in a molar ratio of 2.05:1:0.01, heat to 80°C for preheating, dissolve the solid in the reaction system completely, and keep the pre-reaction at normal pressure for 1h; then heat to 125°C, control the vacuum degree in the reactor at -0.01Mpa by a vacuum pump, and carry out esterification reaction. At the same time, use a water separator to separate the distilled water and isooctyl alcohol, and the isooctyl alcohol is recovered for the next esterification reaction. During the esterification reaction, the acid value is measured every 0.5h and the esterification rate is calculated. When the esterification rate reaches more than 98%, the reaction is stopped;

[0063] S2, sulfonation reaction: This step is the same as Example 1, and a crude product of diisooctyl succinate is obtained; NaHSO3, a phase transfer catalyst AOT and distilled water are added to the reaction system after neutralization treatment, the temperature is raised to 125°C, and the sulfonation reaction is maintained for 2 hours. At the same time, a condenser is used to condense the water vapor generated during the reaction into water and then flow back into the reactor to keep the system fluid. During the reaction, the iodine value is sampled and measured every 0.5 hours, and the sulfonation rate is calculated. The reaction is stopped when the sulfonation rate reaches more than 96%; wherein the molar ratio of diisooctyl succinate to NaHSO3 is 1:1.2, the mass ratio of the phase transfer catalyst AOT to diisooctyl succinate is 2:100, and the mass ratio of distilled water to NaHSO3 is 1.55:1;

[0064] S3, azeotropic dehydration: add n-hexane to the reaction system after the sulfonation reaction is completed, stir to completely dissolve the sulfonation product, heat to 65°C, make n-hexane and water azeotropically remove water, and use a condensation water separator to separate the distilled water and n-hexane, and the separated n-hexane flows back into the reactor to keep the system fluidity, and continue to participate in the sulfonation reaction of step S2 after water recovery. When the water content is lower than 0.1wt%, stop heating, let it stand and cool, precipitate solid (inorganic salt), filter, and obtain filtrate;

[0065] S4, recovering the entrainer: transferring the obtained filtrate to a reactor, then adding a small amount of DMAC to maintain the fluidity inside the reaction system, heating to 75°C, distilling out the n-hexane in the reactor under normal pressure and recovering it, and obtaining crude sodium succinate sulfonate (LDSS), wherein the ratio of the added amount of DMAC to the theoretical mass of the spandex cohesive agent is 30:100;

[0066] S5. Preparation of spandex bonding agent: This step is basically the same as Example 1, except that perlite is replaced with white active soil, and the ratio of the added amount of white active soil to the theoretical mass of the spandex bonding agent is 1:100, to obtain a spandex bonding agent-OT35 product, recorded as E5.

[0067] Example 6

[0068] S1, esterification reaction: This step is the same as in Example 1;

[0069] S2, sulfonation reaction: adding saturated Na2CO3 aqueous solution to the system of step S1, adjusting the pH of the reaction product in the system to 8.4, and obtaining a crude product of diisooctyl succinate; adding NaHSO3, phase transfer catalyst AOT and distilled water to the reaction system after neutralization treatment, heating to 110°C, maintaining the sulfonation reaction for 4 hours, and using a condenser to condense the water vapor generated during the reaction into water and then flow back into the reactor to keep the system fluid. During the reaction, sampling and measuring the iodine value every 0.5 hours, calculating the sulfonation rate, and stopping the reaction when the sulfonation rate reaches more than 96%; wherein the molar ratio of diisooctyl succinate to NaHSO3 is 1:1, the mass ratio of the phase transfer catalyst AOT to diisooctyl succinate is 15:100, and the mass ratio of distilled water to NaHSO3 is 1.35:1;

[0070] S3, azeotropic dehydration: This step is the same as in Example 1;

[0071] S4, recovering the entrainer: this step is the same as in Example 1;

[0072] S5. Preparation of spandex cohesive agent: This step is basically the same as Example 1, except that perlite is replaced by cellulose, and the ratio of the added amount of cellulose to the theoretical mass of the spandex cohesive agent is 0.05:100, to obtain a spandex cohesive agent-OT35 product, recorded as E6.

[0073] Comparative Example 1

[0074] In this comparative example, the spandex bonding agent OT35 product prepared by the existing production process (see background technology) is denoted as D1.

[0075] The relevant indicators of the spandex bonding agent-OT35 product obtained in Examples 1-6 of the present invention and Comparative Example 1 are shown in Table 1 below.

[0076] Table 1 Related indicators of each spandex bonding agent-OT35 product obtained

[0077] Test items Technical index requirements E1 E2 E3 E4 E5 E6 D1 Appearance White liquid White liquid White liquid White liquid White liquid White liquid White liquid White liquid Chroma (APHA) ≤ 60 45 51 48 50 46 49 68 Active ingredient / % ≥ 99.5 99.8 99.5 99.8 99.6 99.5 99.8 94.6 Acid value ≤ 2.5 1.3 1.6 1.5 1.2 1.6 1.3 2.3 Moisture / % ≤ 0.5 0.03 0.05 0.08 0.05 0.07 0.03 0.8 pH (1% aqueous solution, 20 ℃) 5.5~7.0 6.2 6.0 5.9 6.4 6.5 6.4 7.5

[0078] It can be seen from the results in Table 1 that the spandex cohesive agent-OT35 products prepared in Examples 1-6 can all meet the technical index requirements of the existing spandex cohesive agent-OT35 product (D3).

[0079] The spandex bonding agent-OT35 products (E1-E6) prepared in Examples 1-6, the spandex bonding agent-OT35 product (D1) prepared by the prior art, and the commercially available AOT product were applied to spandex yarns, and their performance was compared with that of spandex yarns without the spandex bonding agent (blank). The results are shown in Table 2 below.

[0080] Table 2 Performance comparison results

[0081] sample Breaking strength / cn Holding force / g Spandex yarn without spandex bonding agent (blank) 50.2 0.20 Spandex yarn using spandex bonding agent-OT35 (E1) 59.5 0.37 Spandex yarn using spandex bonding agent-OT35 (E2) 59.6 0.38 Spandex yarn using spandex bonding agent-OT35 (E3) 59.5 0.38 Spandex yarn using spandex bonding agent-OT35 (E4) 59.6 0.37 Spandex yarn using spandex bonding agent-OT35 (E5) 59.5 0.38 Spandex yarn using spandex bonding agent-OT35 (E6) 59.6 0.38 Spandex yarn using spandex bonding agent-OT35 (D1) 59.5 0.37 Use commercially available AOT spandex yarn 40.7 0.18

[0082] It can be seen from the results in Table 2 that the spandex cohesive agent products prepared in Examples 1-6 of the present invention have the same or even better effects as the existing spandex cohesive agent (D1) in the production of spandex yarns; while the commercially available AOT products, due to their high inorganic salt content, will corrode the spandex yarns, causing the breaking strength and cohesive force of the spandex yarns to decrease.

[0083] The present invention is not limited to the above-mentioned specific implementation modes. Various changes made by ordinary technicians in this field based on the above-mentioned concepts without creative work are all within the protection scope of the present invention.

Claims

1. A production process of a spandex cohesive agent, characterized in that: The following steps are involved: S1, esterification reaction: isooctyl alcohol, maleic anhydride and p-toluenesulfonic acid are mixed, preheated and pre-reacted, and then heated and esterified under reduced pressure distillation; S2, sulfonation reaction: add saturated Na2CO3 aqueous solution to the reaction system after the esterification reaction in step S1 to adjust the pH to 7-8.4 to obtain a crude product of diisooctyl succinate; add NaHSO3, phase transfer catalyst AOT and distilled water to the neutralized reaction system, increase the temperature, and carry out sulfonation reaction; S3, azeotropic dehydration: adding an azeotropic agent to the reaction system after the sulfonation reaction in step S2, heating until the azeotropic agent and water produce azeotropy, and removing water; S4, recovering the entrainer: adding a certain amount of DMAC to the reaction system after dehydration, heating, distilling at normal pressure, distilling out the entrainer in the reaction system and recovering it to obtain crude sodium sulfosuccinate; S5, preparing a spandex cohesive agent: adding DMAC and a filter aid to the crude sodium sulfosuccinate, filtering, and obtaining a DMAC solution of sodium sulfosuccinate with a mass concentration of 35%, which is a spandex cohesive agent; The amount of the entrainer added is the same as the theoretical mass of the spandex cohesive agent, and the entrainer is any one of toluene, ethyl acetate, cyclohexane, chloroform and n-hexane; During the azeotropic dehydration process, the distilled water and the entrainer are separated by a condensation water separator, and the separated entrainer flows back into the reaction system to maintain the fluidity of the system. After the water is recovered, the sulfonation reaction in step S2 is continued. When the water content is lower than 0.2wt%, the heating is stopped, the mixture is allowed to cool, a solid is precipitated, and the mixture is filtered to obtain a filtrate. The theoretical mass ratio of the added amount of DMAC to the spandex bonding agent is 20-40:100; The filter aid is any one of white active soil, activated carbon, cellulose and perlite, and the ratio of the added amount of the filter aid to the theoretical mass of the spandex bonding agent is 0.01-1:

100.

2. The production process of the spandex cohesive agent according to claim 1, characterized in that: In step S1, during the esterification reaction, a water separator is used to separate the distilled water and isooctyl alcohol, the isooctyl alcohol is used for the next esterification reaction, and the water participates in the sulfonation reaction of the next step S2.

3. The production process of the spandex cohesive agent according to claim 1, characterized in that: In step S1, maleic anhydride, isooctyl alcohol and p-toluenesulfonic acid are mixed, preheated and pre-reacted, then heated, and esterification reaction is carried out under reduced pressure distillation. The specific steps are: maleic anhydride, isooctyl alcohol and p-toluenesulfonic acid are mixed, preheated to 75-85°C, pre-reacted for 0.5-3.0 h, then heated to 110-125°C, and maintained under reduced pressure distillation for esterification reaction for 2-3.5 h; wherein the vacuum degree under reduced pressure distillation is -0.01~-0.2 Mpa, and the molar ratio of maleic anhydride, isooctyl alcohol and p-toluenesulfonic acid is 1:2-2.55:0.01-0.

1.

4. The production process of the spandex cohesive agent according to claim 1, characterized in that: In step S2, the temperature of the sulfonation reaction is 110-140°C, the time of the sulfonation reaction is 3-6 h; the molar ratio of diisooctyl succinate to NaHSO3 is 1:1-1.5, the mass ratio of the phase transfer catalyst AOT to diisooctyl succinate is 2-15:100, and the mass ratio of distilled water to NaHSO3 is 1.35-2.0:1.

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