Hydrophilic separation membrane with antibacterial property as well as preparation method and application of hydrophilic separation membrane

Abstract

According to the hydrophilic separation membrane with the antibacterial property, the preparation method of the hydrophilic separation membrane and the application of the hydrophilic separation membrane in preparation of polyester polyol, the separation membrane with high water selectivity, good permeability and excellent antibacterial property can be prepared by regulating and controlling materials of an organic phase monomer and a water phase monomer; when the obtained hydrophilic separation membrane is used for preparation of polyester polyol, efficient separation of alcohol water vapor is realized, dihydric alcohol obtained through separation can be reused in a reaction system, alcohol loss is effectively reduced, imbalance of the alcohol-acid ratio is prevented, meanwhile, the content of bacteria in the system can be reduced, and the storage period of a polyester polyol product is prolonged; in addition, by adjusting the feeding mode of the dihydric alcohol, the water generation amount in the esterification process is kept stable, the entrainment and side reaction of the dihydric alcohol are reduced, the flooding problem is avoided, and the polyester polyol with stable indexes is obtained.

Description

Technical Field

[0001] The present invention belongs to the field of membrane technology and organic polymer compound technology, and relates to a hydrophilic separation membrane with antibacterial properties, a preparation method and application thereof, and specifically relates to a hydrophilic separation membrane, a preparation method thereof and application thereof in the preparation of polyester polyols. Background Art

[0002] As an important chemical raw material, polyester polyols are widely used in polyurethane resins, coatings, adhesives, elastomers, plastics and other fields. Polyester polyols are a kind of polymer prepared by polycondensation reaction of polycarboxylic acids and polyols. Usually, polyester polyols are prepared from dibasic acids and diols. Among aliphatic polyester polyols, adipic acid polyester diols are the most widely used. There are three main synthesis methods: vacuum melting method, gas carrier melting method and azeotropic melting method, and their principles are basically the same.

[0003] At present, most of the polyester polyol reactions are prepared by vacuum melting method, and the reaction process is divided into two steps: the first step is the esterification reaction of diol and dibasic acid to generate ester and water; the second step is the condensation reaction of monomer and monomer, monomer and oligomer, oligomer and oligomer under the action of catalyst to obtain polyester polyol products, and generate by-product water and small molecule alcohol at the same time. The device system used is connected to the reactor by a distillation tower to continuously remove a large amount of by-product water produced by the reaction from the reaction system. After the water vapor enters the distillation tower, as the water vapor velocity increases, four different gas-liquid contact states will gradually appear in the distillation tower, namely, bubbling state, honeycomb state, foam state and injection state. When a large amount of water vapor is generated, the gas-liquid contact reaches the foam state and injection state, which will cause diol entrainment, resulting in large loss of polyol, large COD value in wastewater, and high treatment cost. When the amount of water vapor generated is large, the rise of a large amount of steam will prevent the reflux liquid in the distillation tower from being smoothly retained, and the accumulation of reflux liquid will cause flooding in the distillation tower, affecting the distillation operation.

[0004] In the prior art, when some diols with higher freezing points (such as neopentyl glycol) are used as raw materials, it is easy to cause the problem of blockage of the reaction distillation tower or pipeline, and the blockage of the device leads to a decrease in reaction efficiency, and even leads to substandard product quality. In addition, the diol feed rate will also affect the amount of water generated. If the diol feed rate is too fast, the esterification reaction is violent, the amount of water generated is large, and a large amount of water vapor rises, which will increase the entrainment of raw materials such as alcohol. CN103804670B, CN111333823A, etc., under the condition of fixed feed ratio, achieve products with qualified hydroxyl value by one-time feeding, gradient heating and simultaneous control of acid value and hydroxyl value. The method of adding alcohol is often used in industry to make up for the alcohol lost in the early prepolymerization and polymerization process, but this method is less effective.

[0005] In addition, the bacteria and fungi present in the production of polyester polyols will shorten their storage period, affect their stability, and further affect the downstream process of polyester polyols. The downstream product of polyester polyols, water-based polyurethane, has extremely strict requirements on the bacterial content. Bacteria in the product will make it smelly, affecting its use. CN117720704A kills bacteria in polyurethane by adding antibacterial materials, but this method is relatively cumbersome and cannot solve the problem of bacterial content from the root.

[0006] In summary, providing a method and device system for producing polyester polyols with reduced polyol entrainment and side reactions and excellent performance is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0007] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a hydrophilic separation membrane with antibacterial properties and a preparation method and application thereof. The hydrophilic separation membrane has high water selectivity, good permeability and excellent antibacterial properties. When used in the preparation of polyester polyols, it can achieve efficient separation of alcohol and water vapor, and the separated diols can be recycled to the reaction system, effectively reducing alcohol loss and preventing an imbalance in the alcohol-acid ratio. At the same time, it can also reduce the bacterial content in the system and extend the storage period of the polyester polyol products. In the preparation process of polyester polyols, by adjusting the feeding method of diols, the water generation in the esterification process is kept stable, the entrainment and side reactions of diols are reduced, and the occurrence of flooding problems is avoided.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a hydrophilic separation membrane with antibacterial properties, the hydrophilic separation membrane comprising a base membrane and a separation layer deposited on the surface of the base membrane;

[0010] The separation layer is prepared by cross-linking and polymerization of aqueous phase monomers and organic phase monomers;

[0011] The aqueous phase monomer includes a guanidine compound;

[0012] The organic phase monomer contains at least 3 carboxyl groups, for example, 3, 4 or 5, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0013] The hydrophilic separation membrane provided by the present invention can prepare a separation membrane with high water selectivity, good permeability and excellent antibacterial property by cross-linking and polymerizing specific water phase monomers and organic phase monomers on a base membrane; wherein the selected organic phase monomer contains more hydrophilic carboxyl groups, has greater affinity for water, is easily wetted by water, and can increase water permeability; the selected water phase monomer is a guanidine compound, which, compared with other antibacterial monomers, contains more amino-like groups on the one hand, which can enhance the hydrophilicity of the membrane; on the other hand, it is positively charged as a whole, and can act on the negatively charged outer layer of the bacterial / fungal cell membrane in a bidentate binding manner, destroying the bacterial cells, making the cells unable to metabolize or even die.

[0014] It is worth noting that guanidine compounds have strong reactivity. At low concentrations, guanidine compounds diffuse to the surface of the organic phase, and the amine groups contained in the guanidine compounds react with the organic phase monomers containing carboxyl groups at the interface of the base membrane to form amides, which, after polymerization, form a polyamide antibacterial hydrophilic separation membrane with a network cross-linked structure.

[0015] As a preferred technical solution of the present invention, the base membrane includes any one of a polyacrylonitrile base membrane, a polysulfone base membrane or a polyvinylidene fluoride based membrane, or a combination of at least two of them; wherein the combinations are typical but not limiting: a combination of a polyacrylonitrile base membrane and a polysulfone base membrane, a combination of a polysulfone base membrane and a polyvinylidene fluoride based membrane, or a polyacrylonitrile base membrane, a polysulfone base membrane and a polyvinylidene fluoride based membrane, etc.

[0016] In the present invention, the polysulfone-based membrane includes a polyethersulfone-based membrane. The present invention does not specifically limit the structure and parameters of the base membrane, as long as it can play a role in structural support and interface bonding, it can be used in the present invention, and those skilled in the art can select it according to actual needs.

[0017] Preferably, the molar ratio of the aqueous phase monomer to the organic phase monomer is 1:(0.4-2.4), for example, it can be 1:0.4, 1:0.5, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.6, 1:1.8, 1:2, 1:2.2 or 1:2.4, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 1:(0.5-2.0).

[0018] Preferably, the organic phase monomer comprises a first compound containing a nitrogen heterocycle and a carboxyl group, and the number of the carboxyl groups is at least 3.

[0019] Preferably, the first compound comprises any one of pyrazinetetracarboxylic acid, 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine or 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine, or a combination of at least two thereof; wherein the combination is typical but not limiting and includes: a combination of 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine and pyrazinetetracarboxylic acid, a combination of pyrazinetetracarboxylic acid and 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine, or 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine, pyrazinetetracarboxylic acid and 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine, and the like.

[0020] Preferably, the guanidine compound includes any one of 1,3-diaminoguanidine hydrochloride, agmatine sulfate, polyhexamethyleneguanidine hydrochloride, biguanide or polyhexamethylene biguanide, or a combination of at least two thereof; wherein the combination is typical but not limiting and includes: a combination of 1,3-diaminoguanidine hydrochloride and agmatine sulfate, polyhexamethyleneguanidine hydrochloride and biguanide or pyrazine-2,3-dicarboxylic acid, polyhexamethylene biguanide and 1,3-diaminoguanidine hydrochloride, etc.

[0021] As a preferred technical solution of the present invention, the pore size of the hydrophilic separation membrane is 1-10nm, for example, it can be 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] It is worth mentioning that the hydrophilic separation membrane can be used to separate alcohol-water mixtures, and its separation mechanism is as follows: the selected monomers have more hydrophilic groups, have a strong affinity for water, can attract water molecules, and are easily wetted by water. The prepared membrane is a hydrophilic membrane, and its hydrophilicity makes the adhesion strength of water on the membrane surface greater than the cohesive strength. Therefore, when the alcohol-water mixture contacts the membrane surface, through the action of hydrogen bonds, water quickly spreads on the membrane surface and forms a hydration layer. The strong adhesion of water and the downward capillary force make the water continue to penetrate downward, and since alcohols and the like have a large surface tension on the surface of the hydration layer, alcohols and the like float on the surface of the hydration layer to reduce the interfacial tension; in addition, the pore size of the prepared membrane is between 1-10nm, the diameter of water molecules is about 0.28nm, and they can pass through the membrane pores smoothly, while the hydration radius of raw materials such as alcohols is larger than the membrane pore size and will be retained by the membrane. Therefore, the hydrophilic separation membrane provided by the present invention achieves the separation purpose by the synergistic effect of the above two methods, relying on the different dissolution (or adsorption) and diffusion rates of each component in the alcohol-water mixture in the membrane. The separation process is not limited by gas-liquid equilibrium, thereby realizing the separation of the alcohol-water mixture.

[0023] Preferably, the permeate side surface pressure of the hydrophilic separation membrane is 0.1-1 MPa, for example, it can be 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa or 1 MPa, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 0.1-0.2 MPa.

[0024] Preferably, the absolute pressure on the osmotic side of the hydrophilic separation membrane is 0.1-50 kPa, for example, it can be 0.1 kPa, 1 kPa, 3 kPa, 5 kPa, 8 kPa, 10 kPa, 15 kPa, 20 kPa, 30 kPa, 35 kPa, 40 kPa, 45 kPa or 50 kPa, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 1-10 kPa.

[0025] In a second aspect, the present invention provides a method for preparing the hydrophilic separation membrane according to the first aspect, the preparation method comprising the following steps:

[0026] providing a basement membrane;

[0027] placing the aqueous phase reaction liquid on the surface of the base film and allowing it to stand to obtain a base film that absorbs the aqueous phase monomer;

[0028] The organic phase reaction liquid is placed on the surface of the base membrane adsorbing the aqueous phase monomer, and then an interfacial polymerization reaction is carried out to obtain the hydrophilic separation membrane.

[0029] In the present invention, washing is further performed after the interfacial polymerization reaction to remove unreacted monomers on the membrane surface and improve the surface quality of the hydrophilic separation membrane.

[0030] The preparation method provided by the present invention prepares a hydrophilic separation membrane with antibacterial function on the surface of a base membrane by a deposition-polymerization method. The preparation method has simple process, mild preparation conditions, wide application range, and is easy to scale up and realize industrial production.

[0031] As a preferred technical solution of the present invention, the mass concentration of the aqueous phase reaction liquid is 0.5-1.5wt%, for example, it can be 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt% or 1.5wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] In the present invention, the solvent in the aqueous phase reaction liquid is water.

[0033] Preferably, the standing temperature is 55-65°C, for example, it can be 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C or 65°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the standing time is 50-70 min, for example, it can be 50 min, 52 min, 55 min, 56 min, 58 min, 60 min, 62 min, 65 min, 66 min, 68 min or 70 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] In the present invention, the aqueous phase monomer diffuses into the pores of the basement membrane during the standing process.

[0036] Preferably, after the standing, excess solution is removed.

[0037] Preferably, the mass concentration of the organic phase reaction liquid is 0.5-2.5wt%, for example, it can be 0.5wt%, 0.8wt%, 0.9wt%, 1.1wt%, 1.3wt%, 1.5wt%, 1.7wt%, 1.9wt%, 2.1wt%, 2.3wt% or 2.5wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] In the present invention, the solvent in the organic phase reaction liquid includes ethyl acetate.

[0039] Preferably, the temperature of the interfacial polymerization reaction is 55-65°C, for example, it can be 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C or 65°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the time of the interfacial polymerization reaction is 50-70 min, for example, it can be 50 min, 52 min, 55 min, 56 min, 58 min, 60 min, 62 min, 65 min, 66 min, 68 min or 70 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] In a third aspect, the present invention provides a method for preparing a polyester polyol, the method comprising the following steps:

[0042] (1) Under the protection of inert gas, the dibasic acid and the diol fed once react;

[0043] (2) when water is extracted from the material obtained in step (1), adding diol as a secondary feed to continue the reaction, and at the same time separating the extracted alcohol water vapor using the hydrophilic separation membrane described in the first aspect or the hydrophilic separation membrane prepared by the preparation method described in the second aspect;

[0044] wherein the alcohol separated from the alcohol water vapor is recycled to step (1);

[0045] (3) adding a catalyst to the material obtained in step (2) to continue the reaction to obtain the polyester polyol.

[0046] In the present invention, the reaction pressure is 1000Pa (absolute pressure)-0.2Mpa (gauge pressure); the total residence time of the raw materials in the reaction is 6-28h, preferably 8-20h.

[0047] In the present invention, the extracted alcohol water vapor is condensed and the negative pressure on the permeation side of the hydrophilic separation membrane provided by the vacuum device is used as a driving force to separate the water and diol in the rising steam. The water vapor is collected in a water storage tank, and the alcohol that has not permeated is recycled to the reaction system.

[0048] The preparation method of the polyester polyol provided by the present invention can keep the amount of water generated in the esterification process stable by adjusting the feeding mode of the diol, reduce the entrainment and side reaction of the diol, avoid the generation of the flooding problem, and obtain the polyester polyol with stable indicators; and can be used in combination with a hydrophilic separation membrane with antibacterial function in the synthesis system to achieve efficient separation of alcohol and water vapor, and the separated diol can be returned to the reaction system, effectively reducing the alcohol loss and preventing the imbalance of the alcohol-acid ratio, and can also reduce the bacterial content in the system, prolong the storage period of the polyester polyol product, increase its stability, and significantly reduce the COD value of the collected wastewater, thereby greatly reducing the cost of biochemical treatment of wastewater.

[0049] As a preferred technical solution of the present invention, the dibasic acid in step (1) includes any one of succinic acid, adipic acid, glutaric acid or phthalic acid, or a combination of at least two of them; wherein the combinations are typically but not limited to: a combination of succinic acid and adipic acid, a combination of adipic acid and glutaric acid, or glutaric acid or phthalic acid, etc.

[0050] Preferably, the diol in step (1) comprises any one of ethylene glycol, 1,4-butanediol, propylene glycol, diethylene glycol, neopentyl glycol or 1,6-hexanediol, or a combination of at least two thereof; wherein the combinations are typically but not limited to: a combination of ethylene glycol and 1,4-butanediol, a combination of propylene glycol and diethylene glycol, or neopentyl glycol or 1,6-hexanediol, etc.

[0051] Preferably, the molar ratio of the primary feed amount of the diol in step (1) to the dibasic acid is (0.25-0.7):1, for example, it can be 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.6:1, 0.65:1 or 0.7:1, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably (0.33-0.5):1.

[0052] In the present invention, if one-time feeding is adopted, a large amount of water is produced in a short time, and a high gas velocity may cause excessive diol entrainment loss, causing an imbalance in the alcohol-acid ratio. Therefore, the inventor adjusted the feeding method of diol and controlled the molar ratio of the one-time feeding amount of diol to the dibasic acid within the range of (0.25-0.7):1.

[0053] Preferably, before carrying out the reaction in step (1), the dibasic acid and the diol fed once are preheated.

[0054] Preferably, the preheating heating rate is 40-50°C / h, for example, it can be 40°C / h, 41°C / h, 42°C / h, 43°C / h, 44°C / h, 45°C / h, 46°C / h, 47°C / h, 48°C / h, 49°C / h or 50°C / h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] Preferably, the endpoint temperature of the preheating is 110-130°C, for example, it can be 110°C, 112°C, 115°C, 116°C, 118°C, 120°C, 122°C, 125°C, 126°C, 128°C or 130°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0056] Preferably, the heating rate of the reaction is 20-30°C / h, for example, it can be 20°C / h, 21°C / h, 22°C / h, 23°C / h, 24°C / h, 25°C / h, 26°C / h, 27°C / h, 28°C / h, 29°C / h or 30°C / h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] In the present invention, the reaction is carried out under stirring, the reaction process adopts a gradient temperature increase method to the temperature increase end point, and water is extracted during the reaction temperature increase process.

[0058] Preferably, the endpoint temperature of the reaction is 220-240°C, for example, it can be 220°C, 222°C, 225°C, 226°C, 228°C, 230°C, 232°C, 235°C, 236°C, 238°C or 240°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] As a preferred technical solution of the present invention, the molar ratio of the total feed amount of the diol to the dibasic acid is (1.01-1.5):1, for example, it can be 1.01:1, 1.05:1, 1.06:1, 1.08:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, 1.4:1 or 1.5:1, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably (1.07-1.13):1.

[0060] Preferably, the feed rate of the diol in the secondary feed in step (2) is carried out using the following formula:

[0061]

[0062] Among them, v diol is the feed rate of diol for secondary feed (g / min);

[0063] is the relative molecular weight of water;

[0064] is the water extraction rate (g / min);

[0065] M diol is the relative molecular weight of the diol.

[0066] It is worth noting that the secondary feed rate of diols is interlocked with the water withdrawal rate. The secondary feed rate of alcohols is regulated by the water withdrawal amount, and the reaction rate is further controlled to keep the amount of water generated in the esterification process stable, which can effectively reduce the entrainment of polyols and flooding problems.

[0067] Preferably, when the acid value of the material obtained in step (3) is less than 30 mgKOH / g, for example, it can be 28 mgKOH / g, 26 mgKOH / g, 25 mgKOH / g, 24 mgKOH / g, 22 mgKOH / g or 20 mgKOH / g, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, and a catalyst is added.

[0068] Preferably, relative to the total amount of raw materials added, the amount of the catalyst used in step (3) is 10-90 ppm, for example, it can be 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm or 90 ppm, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 10-30 ppm.

[0069] In the present invention, the catalyst includes any one or a combination of at least two of antimony, germanium, titanium and tin catalysts, preferably tetraisopropyl titanate, tetraisobutyl titanate, n-butyl titanate, antimony trioxide, antimony acetate, antimony glycol, germanium dioxide, stannous chloride, tin acetate or di-n-butyltin oxide.

[0070] Preferably, after adding the catalyst in step (3), the process further comprises: when the acid value of the obtained material is less than 20 mgKOH / g, for example, it may be 18 mgKOH / g, 16 mgKOH / g, 15 mgKOH / g, 12 mgKOH / g, 10 mgKOH / g or 5 mgKOH / g, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable, and the alcohol separated from the alcohol vapor is collected in an alcohol storage tank.

[0071] In the present invention, after water is extracted, the alcohol water vapor generated in the early reaction process is separated through a hydrophilic separation membrane, and the separated alcohol is recycled to the reaction system and can effectively reduce the bacterial content in the system. The alcohol separated in the later stage of the reaction is collected in an alcohol storage tank and can be recycled as a raw material in the next batch. The recycled alcohol can also effectively reduce the bacterial content in the system.

[0072] Preferably, when the acid value of the material obtained in step (3) is less than 0.2 mgKOH / g, the reaction is terminated.

[0073] In a fourth aspect, the present invention provides a device system for preparing polyester polyols, the device system comprising a reaction device and a separation and recovery unit connected to each other;

[0074] A pump assembly and a first valve are sequentially arranged on the feed pipeline connected to the reaction device;

[0075] The separation and recovery unit comprises a packing tower, a condensing device, a separation device, a vacuum device, a water storage tank and an alcohol storage tank;

[0076] The separation device is provided with the hydrophilic separation membrane described in the first aspect or the hydrophilic separation membrane prepared by the preparation method described in the second aspect;

[0077] The reaction device is connected to the packing tower, the condensing device, and the separation device in sequence through pipelines;

[0078] A flow component is provided on the pipeline connecting the packing tower and the condensing device, and the flow component is connected to the first valve;

[0079] The outlet of the separation device is independently connected to the water storage tank, the alcohol storage tank, and the reaction device respectively;

[0080] The vacuum device is independently connected to the water storage tank and the alcohol storage tank respectively.

[0081] The device system provided by the present invention adds a separation device in the separation and recovery unit, and the separation device has a hydrophilic separation membrane with antibacterial properties. In addition, the vacuum device required by the separation device can also be shared with the reaction device, thereby improving the utilization rate of the equipment.

[0082] As a preferred technical solution of the present invention, a second valve is provided on the pipeline connecting the separation device and the water storage tank.

[0083] Preferably, a third valve is provided on the pipeline connecting the water storage tank and the vacuum device.

[0084] Preferably, a fourth valve is provided on the pipeline connecting the reaction device and the separation device.

[0085] Preferably, a fifth valve is provided on the pipeline connecting the separation device and the alcohol storage tank.

[0086] Preferably, a sixth valve is provided on the pipeline connecting the alcohol storage tank and the vacuum device.

[0087] In the present invention, when the temperature rises to a certain temperature, the vacuum device, the second valve, the third valve and the fourth valve are opened, and the generated alcohol water vapor is condensed and the negative pressure on the membrane permeation side provided by the vacuum device is used as a driving force to separate the water and polyol in the rising steam; the vacuum device required for the separation device can also be shared with the reaction device.

[0088] Compared with the prior art, the present invention has the following beneficial effects:

[0089] (1) The hydrophilic separation membrane and the preparation method thereof provided by the present invention use a compound containing a large number of hydrophilic groups and a guanidine compound as an organic phase monomer and an aqueous phase monomer, respectively, and prepare them on the surface of the base membrane by a deposition-polymerization method, so as to obtain a separation membrane with high water selectivity, good permeability and excellent antibacterial properties; the preparation method is simple in process, mild in preparation conditions, has a wide range of applications, is easy to scale up and realize industrial production;

[0090] (2) The hydrophilic separation membrane provided by the present invention, when used in the preparation of polyester polyols, can achieve efficient separation of alcohol and water vapor, and can return the separated alcohol to the reaction device, effectively reducing alcohol loss and preventing imbalance of alcohol-acid ratio. At the same time, it can also reduce the bacterial content in the system, extend the storage period of polyester polyol products, increase their stability, and significantly reduce the COD value of the collected wastewater, greatly reducing the cost of wastewater biochemical treatment;

[0091] (3) The preparation method of polyester polyol provided by the present invention adjusts the feeding method of diol so as to keep the amount of water generated in the esterification process stable, reduce the entrainment and side reactions of diol, and avoid the occurrence of flooding problems, thereby obtaining polyester polyol with stable indicators;

[0092] (4) The polyester polyol device system provided by the present invention uses the vacuum device required by the separation device and the reaction device in common, thereby improving the utilization rate of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 The device system for preparing polyester polyol provided in Application Example 1;

[0094] Among them, 1-reaction device, 2-packing tower, 3-separation device, 4-condensation device, 5-water storage tank, 6-alcohol storage tank, 7-vacuum device, 8-pump assembly, 9-first valve, 10-flow assembly, 11-second valve, 12-third valve, 13-fourth valve, 14-fifth valve, 15-sixth valve. DETAILED DESCRIPTION

[0095] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0096] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0097] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0098] In the specific implementation manner of the present invention, the base membrane and other raw materials used are all commercially available products; the pore size of the prepared hydrophilic separation membrane, the membrane permeate side pressure and the membrane permeate side absolute pressure parameters are measured using conventional testing methods in the prior art, and the performance parameters of the prepared polyester polyols are also measured using conventional testing methods in the prior art, which are not specifically limited here.

[0099] Example 1

[0100] This embodiment provides a hydrophilic separation membrane with antibacterial properties and a preparation method thereof, wherein the hydrophilic separation membrane comprises a base membrane and a separation layer deposited on the surface of the base membrane;

[0101] The separation layer is prepared by cross-linking and polymerization of aqueous phase monomers and organic phase monomers;

[0102] The base film is a polyacrylonitrile base film; the aqueous phase monomer is 1,3-diaminoguanidine hydrochloride; and the organic phase monomer is 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine;

[0103] The preparation method comprises the following steps:

[0104] providing a basement membrane;

[0105] Prepare 20 g of an aqueous reaction solution with a mass concentration of 1 wt % and 20 g of an organic reaction solution with a mass concentration of 2 wt % respectively;

[0106] The aqueous reaction liquid is placed on the surface of the base film, and allowed to stand at a temperature of 60° C. for 60 minutes, and then excess aqueous reaction liquid is removed to obtain a base film adsorbing aqueous monomers;

[0107] The organic phase reaction liquid is placed on the surface of the base membrane adsorbing the aqueous phase monomer, the solvent of the organic phase reaction liquid is ethyl acetate, and then an interfacial polymerization reaction is carried out at a temperature of 60° C. for 60 minutes, and then washed to obtain the hydrophilic separation membrane.

[0108] Eight aqueous monomers with different molar weights in the range of 0-2 moles were taken and dissolved in 100 mL of water respectively. The peak area of ​​the characteristic peak of guanidine group in the aqueous monomer solution was detected by Fourier transform infrared spectroscopy (FTIR). The molar weight of aqueous monomer and the peak area of ​​guanidine group were fitted to obtain the standard curve Y 1 =0.353X 1 -0.259(1), where Y 1 is the guanidine peak area, X 1 is the molar amount of the aqueous phase monomer; similarly, the standard curve Y of the molar amount of the organic phase monomer and the peak area of ​​the carboxyl characteristic peak can be obtained 2 =0.412X 2 -0.247(2), where Y 2 is the carboxyl peak area, X 2 is the molar amount of organic phase monomer.

[0109] The hydrophilic separation membrane is subjected to FTIR detection to obtain the guanidine group and hydroxyl group peak areas, which are sequentially substituted into formula (1) and (2). The molar ratio of the aqueous phase monomer to the organic phase monomer is Y 1 :Y 2 .

[0110] After detection and calculation, the molar ratio of the aqueous phase monomer to the organic phase monomer in the separation layer in this embodiment is 1:0.68.

[0111] Example 2

[0112] This embodiment provides a hydrophilic separation membrane with antibacterial properties and a preparation method thereof, wherein the hydrophilic separation membrane comprises a base membrane and a separation layer deposited on the surface of the base membrane;

[0113] The separation layer is prepared by cross-linking and polymerization of aqueous phase monomers and organic phase monomers;

[0114] The base membrane is a polysulfone base membrane; the aqueous phase monomer is polyhexamethyleneguanidine hydrochloride; and the organic phase monomer is pyrazinetetracarboxylic acid;

[0115] The preparation method comprises the following steps:

[0116] providing a basement membrane;

[0117] Prepare 30g of an aqueous reaction solution with a mass concentration of 1wt% and 30g of an organic reaction solution with a mass concentration of 1wt% respectively;

[0118] The aqueous reaction liquid is placed on the surface of the base film, and allowed to stand at a temperature of 55° C. for 70 minutes, and then excess aqueous reaction liquid is removed to obtain a base film adsorbing aqueous monomers;

[0119] The organic phase reaction liquid is placed on the surface of the base membrane adsorbing the aqueous phase monomer, the solvent of the organic phase reaction liquid is ethyl acetate, and then an interfacial polymerization reaction is carried out at a temperature of 55° C. for 70 minutes, and then washed to obtain the hydrophilic separation membrane.

[0120] After detection and calculation, the molar ratio of the aqueous phase monomer to the organic phase monomer in the separation layer in this embodiment is 1:0.94.

[0121] Example 3

[0122] This embodiment provides a hydrophilic separation membrane with antibacterial properties and a preparation method thereof, wherein the hydrophilic separation membrane comprises a base membrane and a separation layer deposited on the surface of the base membrane;

[0123] The separation layer is prepared by cross-linking polymerization of aqueous phase monomers and organic phase monomers;

[0124] The base film is a polyvinylidene fluoride film; the aqueous phase monomer is agmatine sulfate; and the organic phase monomer is 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine;

[0125] The preparation method comprises the following steps:

[0126] providing a basement membrane;

[0127] Prepare 20 g of an aqueous reaction solution with a mass concentration of 1 wt % and 20 g of an organic reaction solution with a mass concentration of 2 wt % respectively;

[0128] The aqueous reaction liquid is placed on the surface of the base film, and allowed to stand at a temperature of 65° C. for 50 minutes, and then excess aqueous reaction liquid is removed to obtain a base film adsorbing aqueous monomers;

[0129] The organic phase reaction liquid is placed on the surface of the base membrane adsorbing the aqueous phase monomer, the solvent of the organic phase reaction liquid is ethyl acetate, and then an interfacial polymerization reaction is carried out at a temperature of 65° C. for 50 minutes, and then washed to obtain the hydrophilic separation membrane.

[0130] According to detection and calculation, the molar ratio of the aqueous phase monomer to the organic phase monomer in the separation layer in this embodiment is 1:1.03.

[0131] Comparative Example 1

[0132] This comparative example provides a hydrophilic separation membrane with antibacterial properties and a preparation method thereof. Except that the organic phase monomer is 2-pyrazine carboxylate, other conditions are the same as those in Example 1.

[0133] Comparative Example 2

[0134] This comparative example provides a hydrophilic separation membrane with antibacterial properties and a preparation method thereof. Except that the aqueous phase monomer is a halamine compound (ADMH), other conditions are the same as those in Example 1.

[0135] The performance of the hydrophilic separation membranes prepared in the above examples and comparative examples was characterized, and the results are shown in Table 1.

[0136] Table 1

[0137]

[0138] From Table 1, we can see that:

[0139] The hydrophilic separation membrane and the preparation method thereof provided in Examples 1-3 of the present invention have high water selectivity and good permeability, and can be used to separate alcohol-water mixtures.

[0140] From the comparison between Example 1 and Comparative Example 1, it can be seen that when the organic phase monomer contains fewer hydrophilic groups, the amine group and the carboxyl group only react to form amides, and a separation layer with a network cross-linking effect cannot be obtained.

[0141] Application Example 1

[0142] This application example provides a method and device system for preparing polyester polyols, wherein the device system (such as Figure 1 ) comprises a reaction device 1 and a separation and recovery unit connected to each other;

[0143] A pump assembly 8 and a first valve 9 are sequentially arranged on the feed pipeline connected to the reaction device 1;

[0144] The separation and recovery unit comprises a packing tower 2, a condensing device 4, a separation device 3, a vacuum device 7, a water storage tank 5 and an alcohol storage tank 6;

[0145] The separation device 3 is provided with the hydrophilic separation membrane provided in Example 1;

[0146] The reaction device 1 is connected to the packing tower 2, the condensing device 4, and the separation device 3 in sequence through pipelines;

[0147] A flow component 10 is provided on the pipeline connecting the packing tower 2 and the condensing device 4, and the flow component 10 is connected to the first valve 9;

[0148] The outlet of the separation device 3 is independently connected to the water storage tank 5, the alcohol storage tank 6, and the reaction device 1 respectively;

[0149] The vacuum device 7 is independently connected to the water storage tank 5 and the alcohol storage tank 6 respectively;

[0150] A second valve 11 is provided on the pipeline connecting the separation device 3 and the water storage tank 5; a third valve 12 is provided on the pipeline connecting the water storage tank 5 and the vacuum device 7; a fourth valve 13 is provided on the pipeline connecting the reaction device 1 and the separation device 3; a fifth valve 14 is provided on the pipeline connecting the separation device 3 and the alcohol storage tank 6; a sixth valve 15 is provided on the pipeline connecting the alcohol storage tank 6 and the vacuum device 7;

[0151] The method comprises the following steps:

[0152] (1) Under normal pressure and nitrogen purge, 5 kg of adipic acid (34.2 mol) and 1.546 kg of 1,4-butanediol (17.15 mol) were added to the reaction device 1, and the temperature was raised to 120° C. at a heating rate of 50° C. / h for preheating. After the raw materials were melted, the temperature was gradually raised to 220° C. at a heating rate of 25° C. / h for reaction;

[0153] (2) When water is extracted from the material obtained during the heating process of the reaction in step (1), the pump assembly 8 and the first valve 9 are opened, and the secondary feed of 1,4-butanediol is added to the reaction device 1 to continue the reaction. When the feed amount of the secondary feed of 1,4-butanediol reaches 1.889 kg (20.96 mol), the feeding of 1,4-butanediol is stopped, and the pump assembly 8 and the first valve 9 are closed; when the temperature rises to 190° C. during the heating process of the reaction in step (1), the vacuum device 7, the second valve 11, the fourth valve 13 and the third valve 12 are opened, and the extracted alcohol water vapor is separated by the hydrophilic separation membrane provided in Example 1, and the 1,4-butanediol is refluxed to the reaction device 1, and the water enters the water storage tank 5;

[0154] The feed rate of the secondary feed 1,4-butanediol is carried out using the following formula:

[0155]

[0156] (3) When the acid value of the obtained material is 24 mgKOH / g, 10 ppm of di-n-butyltin oxide is added to the reaction device 1 to continue the reaction. When the acid value of the obtained material is 16 mgKOH / g, the alcohol separated from the alcohol vapor is adjusted to be collected in the alcohol storage tank 6, the fourth valve 13 is closed and the fifth valve 14 and the sixth valve 15 are opened, and the pressure of the reaction device 1 is controlled to be 3000 Pa. When the acid value of the obtained material is 0.16 mgKOH / g, the reaction is terminated.

[0157] Application Example 2

[0158] This application example provides a method and device system for preparing polyester polyols. The device system is performed using the method provided in application example 1. The method comprises the following steps:

[0159] (1) Under normal pressure and nitrogen purge, 5 kg of adipic acid (34.2 mol) and 0.77 kg of 1,4-butanediol (8.55 mol) were added to the reaction device, and the temperature was raised to 120° C. at a heating rate of 50° C. / h for preheating. After the raw materials were melted, the temperature was gradually raised to 230° C. at a heating rate of 25° C. / h for reaction;

[0160] (2) When water is extracted from the material obtained during the heating process of the reaction in step (1), the pump assembly and the first valve are opened, and 1,4-butanediol as a secondary feed is added to the reaction device to continue the reaction. When the feed amount of the secondary feed 1,4-butanediol reaches 2.618 kg (29.05 mol), the feeding of 1,4-butanediol is stopped, and the pump assembly and the first valve are closed. When the temperature rises to 190° C. during the heating process of the reaction in step (1), the vacuum device, the second valve, the fourth valve and the third valve are opened, and the alcohol water vapor extracted is separated by the hydrophilic separation membrane provided in Example 2, and the 1,4-butanediol is refluxed into the reaction device, and the water enters the water storage tank;

[0161] The feed rate of the secondary feed 1,4-butanediol is carried out using the following formula:

[0162]

[0163] (3) When the acid value of the obtained material is 26 mgKOH / g, 10 ppm of tin acetate is added to the reaction device to continue the reaction. When the acid value of the obtained material is 18 mgKOH / g, the alcohol separated from the alcohol vapor is adjusted to be collected in an alcohol storage tank, the fourth valve is closed and the fifth and sixth valves are opened, and the pressure of the reaction device is controlled to be 3000 Pa. When the acid value of the obtained material is 0.14 mgKOH / g, the reaction is terminated.

[0164] Application Example 3

[0165] This application example provides a method and device system for preparing polyester polyols. The device system is performed using the method provided in application example 1. The method comprises the following steps:

[0166] (1) Under normal pressure and nitrogen purge, 5 kg of adipic acid (34.2 mol), 2.366 kg of 1,6-hexanediol (20.02 mol) and 0.408 kg of neopentyl glycol (3.92 mol) were added to a reaction device, and the temperature was raised to 120° C. at a heating rate of 50° C. / h for preheating. After the raw materials were melted, the temperature was gradually raised to 230° C. at a heating rate of 25° C. / h for reaction;

[0167] (2) When water is extracted from the material obtained during the heating process of the reaction in step (1), the pump assembly and the first valve are opened, and the neopentyl glycol as a secondary feed is added to the reaction device to continue the reaction. When the feed amount of the neopentyl glycol as the secondary feed reaches 1.926 kg (18.49 mol), the feeding of neopentyl glycol is stopped, and the pump assembly and the first valve are closed. When the temperature rises to 190° C. during the heating process of the reaction in step (1), the vacuum device, the second valve, the fourth valve and the third valve are opened, and the alcohol water vapor extracted is separated by the hydrophilic separation membrane provided in Example 2, and the 1,4-butanediol is refluxed into the reaction device, and the water enters the water storage tank;

[0168] The feed rate of the neopentyl glycol of the secondary feed is carried out using the following formula:

[0169]

[0170] (3) When the acid value of the obtained material is 26 mgKOH / g, 10 ppm of tin acetate is added to the reaction device to continue the reaction. When the acid value of the obtained material is 18 mgKOH / g, the alcohol separated from the alcohol vapor is adjusted to be collected in an alcohol storage tank, the fourth valve is closed and the fifth and sixth valves are opened, and the pressure of the reaction device is controlled to 4000 Pa. When the acid value of the obtained material is 0.14 mgKOH / g, the reaction is terminated.

[0171] Comparative application example 1

[0172] This application example provides a method and device system for preparing polyester polyols. Except that the molar amount of 1,4-butanediol fed in step (1) is 3.42 mol, other conditions are the same as those in application example 1.

[0173] Comparative Application Example 2

[0174] This application example provides a method and device system for preparing polyester polyols. Except that the molar amount of 1,4-butanediol fed in step (1) is 30.54 mol, other conditions are the same as those in application example 1.

[0175] Comparative Application Example 3

[0176] This application example provides a method and device system for preparing polyester polyols. Except that the feed rate of 1,4-butanediol as the secondary feed in step (2) is the same as the water extraction rate, other conditions are the same as those in application example 1.

[0177] Comparative Application Example 4

[0178] This comparative application example provides a method and device system for preparing polyester polyols. Except for using the hydrophilic separation membrane provided in comparative example 2 to separate the extracted alcohol water vapor, other conditions are the same as those in application example 1.

[0179] Comparative Application Example 5

[0180] This comparative application example provides a method and device system for preparing polyester polyols, wherein the separation device is not provided with a hydrophilic separation membrane having antibacterial properties, but only contains a basement membrane; the method comprises the following steps:

[0181] (1) Under normal pressure and nitrogen purge, 5 kg of adipic acid (34.2 mol) and 1.546 kg of 1,4-butanediol (17.15 mol) were added to the reaction device, and the temperature was raised to 120° C. at a heating rate of 50° C. / h for preheating. After the raw materials were melted, the temperature was gradually raised at a heating rate of 25° C. / h for reaction;

[0182] (2) When water is produced from the material obtained during the heating process of the reaction in step (1), a secondary feed of 1,4-butanediol is added to the reaction device to continue the reaction. When the feed amount of the secondary feed of 1,4-butanediol reaches 1.850 kg (20.5 mol), the feed of 1,4-butanediol is stopped;

[0183] The feed rate of the secondary feed 1,4-butanediol is carried out using the following formula:

[0184]

[0185] (3) When the temperature of the reaction device rises to 200° C., the vacuum device is started, and the pressure of the reaction device is controlled to be 3000 Pa and the temperature is raised to 230° C. When the acid value of the obtained material is 26 mgKOH / g, 10 ppm of n-butyltin hydroxide oxide is added to the reaction device to continue the reaction. When the acid value of the obtained material is 15 mgKOH / g, the alcohol is condensed and collected in an alcohol storage tank. When the acid value of the obtained material is 0.19 mgKOH / g, the reaction is terminated;

[0186] In this comparative application example, the alcohol loss is 30 g.

[0187] Comparative Application Example 6

[0188] This comparative application example provides a method and device system for preparing polyester polyols, wherein the separation device is not provided with a hydrophilic separation membrane having antibacterial properties, but only contains a basement membrane; the method comprises the following steps:

[0189] (1) Under normal pressure and nitrogen purge, 5 kg of adipic acid (34.2 mol) and 3.435 kg of 1,4-butanediol (38.12 mol) were added to the reaction device, and the temperature was raised to 120° C. at a heating rate of 50° C. / h for preheating. After the raw materials were melted, the temperature was gradually raised at a heating rate of 25° C. / h for reaction. The water generated during the heating process was condensed and collected in a water storage tank;

[0190] (2) When the temperature of the reaction device rises to 200° C., the vacuum device is started, and the pressure of the reaction device is controlled to be 3000 Pa and the temperature is raised to 230° C. When the acid value of the obtained material is 27 mgKOH / g, 10 ppm of n-butyltin hydroxide oxide is added to the reaction device to continue the reaction. When the acid value of the obtained material is 17 mgKOH / g, the alcohol is condensed and collected in an alcohol storage tank. When the acid value of the obtained material is 0.17 mgKOH / g, the reaction is terminated.

[0191] In this comparative application example, the alcohol loss is 70 g.

[0192] The performance of the products obtained from the above application examples and comparative application examples was tested, and the results are shown in Table 2.

[0193] Table 2

[0194]

[0195] From Table 1 and Table 2, we can see that:

[0196] (1) The hydrophilic separation membrane provided by the present invention, its preparation method and its application in the preparation of polyester polyols, the alcohol loss in the process of preparing polyester polyols is significantly reduced, the hydroxyl value, number average molecular weight and storage period of the obtained polyester polyol products are excellent, the storage days are all more than 370 days, and the COD value of the collected wastewater is all below 2000, thereby reducing the cost of biochemical treatment of wastewater;

[0197] (2) It can be seen from the comparison between Application Example 1 and Comparative Application Examples 1-2 that when the proportion of diol fed once is too low, the diol reacts completely due to the reduced alcohol-acid ratio, but the acid value is still high, resulting in the hydroxyl value of the obtained polyester polyol product being 0, the structure of the polyester polyol changes, and the storage period is greatly shortened; when the proportion of diol fed once is too high, the diol is excessive, resulting in the hydroxyl value of the obtained polyester polyol product being too high, the structure of the polyester polyol changes, and the storage period is greatly shortened;

[0198] (3) From the comparison between Application Example 1 and Comparative Application Example 3, it can be seen that when the alcohol feed rate of the secondary feed is the same as the water withdrawal rate, more diols are entrained. After separation by the membrane system, most of the diols flow back to the reactor, and a small amount of diols enter the wastewater storage tank with water, resulting in a slight decrease in the hydroxyl value of the polyester polyol product and an increase in the COD value of the wastewater, which increases the treatment cost.

[0199] (4) From the comparison between Application Example 1 and Comparative Application Example 4, it can be seen that when the aqueous phase monomer is a halamine compound, the antibacterial effect of the halamine compound is slightly worse than that of the guanidine group, and the antibacterial performance of the obtained hydrophilic separation membrane is poor, which leads to a shortened storage period of the obtained polyester polyol product;

[0200] (5) From the comparison between Application Example 1 and Comparative Application Example 5, it can be seen that when the hydrophilic separation membrane is not used to separate the alcohol water vapor, it is not conducive to reducing the bacterial content in the system, resulting in a low hydroxyl value of the obtained polyester polyol product, a shortened storage period, and a large alcohol loss. This shows that the diol after the alcohol water vapor is separated by the hydrophilic membrane is returned to the reaction device, which can not only reduce the alcohol loss of the system, but also help to increase the storage period of the product;

[0201] (6) From the comparison between comparative application example 5 and comparative application example 6, it can be seen that when the raw materials are fed once, more glycol is entrained, resulting in a large loss of glycol and a higher COD value in the wastewater, which leads to high treatment costs.

[0202] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A hydrophilic separation membrane with antibacterial properties, characterized in that: The hydrophilic separation membrane comprises a base membrane and a separation layer deposited on the surface of the base membrane; The separation layer is prepared by cross-linking and polymerization of aqueous phase monomers and organic phase monomers; The aqueous phase monomer includes a guanidine compound; The organic phase monomer contains at least 3 carboxyl groups.

2. The hydrophilic separation membrane according to claim 1, characterized in that The base film includes any one of a polyacrylonitrile base film, a polysulfone base film or a polyvinylidene fluoride base film or a combination of at least two thereof; Preferably, the molar ratio of the aqueous phase monomer to the organic phase monomer is 1:(0.4-2.4), preferably 1:(0.5-2.0); Preferably, the organic phase monomer comprises a first compound containing a nitrogen heterocycle and a carboxyl group, and the number of the carboxyl groups is at least 3; Preferably, the first compound comprises any one or a combination of at least two of pyrazinetetracarboxylic acid, 2,4,6-tris(aminocaproyl)-1,3,5-triazine or 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine; Preferably, the guanidine compound includes any one or a combination of at least two of 1,3-diaminoguanidine hydrochloride, agmatine sulfate, polyhexamethyleneguanidine hydrochloride, biguanidine or polyhexamethylene biguanide.

3. The hydrophilic separation membrane according to claim 1 or 2, characterized in that The pore size of the hydrophilic separation membrane is 1-10 nm; Preferably, the permeate side surface pressure of the hydrophilic separation membrane is 0.1-1 MPa, preferably 0.1-0.2 MPa; Preferably, the absolute pressure on the permeate side of the hydrophilic separation membrane is 0.1-50 kPa, preferably 1-10 kPa.

4. A method for preparing a hydrophilic separation membrane according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: providing a basement membrane; placing the aqueous phase reaction liquid on the surface of the base film and letting it stand to obtain a base film adsorbing the aqueous phase monomer; The organic phase reaction liquid is placed on the surface of the base membrane adsorbing the aqueous phase monomer, and then an interfacial polymerization reaction is carried out to obtain the hydrophilic separation membrane.

5. The preparation method according to claim 4, characterized in that: The mass concentration of the aqueous phase reaction liquid is 0.5-1.5wt%; Preferably, the standing temperature is 55-65°C; Preferably, the standing time is 50-70 min; Preferably, after the standing, excess solution is removed; Preferably, the mass concentration of the organic phase reaction liquid is 0.5-2.5wt%; Preferably, the temperature of the interfacial polymerization reaction is 55-65°C; Preferably, the interfacial polymerization reaction time is 50-70 min.

6. A method for preparing polyester polyol, characterized in that: The method comprises the following steps: (1) Under the protection of inert gas, the dibasic acid and the diol fed once react; (2) when water is extracted from the material obtained in step (1), adding diol as a secondary feed to continue the reaction, and at the same time separating the extracted alcohol water vapor using the hydrophilic separation membrane described in any one of claims 1 to 3 or the hydrophilic separation membrane prepared by the preparation method described in claim 4 or 5; wherein the alcohol separated from the alcohol water vapor is recycled to step (1); (3) adding a catalyst to the material obtained in step (2) to continue the reaction to obtain the polyester polyol.

7. The method according to claim 6, characterized in that The dibasic acid in step (1) includes any one of succinic acid, adipic acid, glutaric acid or phthalic acid, or a combination of at least two thereof; Preferably, the diol in step (1) comprises any one of ethylene glycol, 1,4-butanediol, propylene glycol, diethylene glycol, neopentyl glycol or 1,6-hexanediol, or a combination of at least two thereof; Preferably, the molar ratio of the primary feed amount of the diol in step (1) to the dibasic acid is (0.25-0.7):1, preferably (0.33-0.5):1; Preferably, before carrying out the reaction in step (1), the process further comprises preheating the dibasic acid and the diol fed once; Preferably, the preheating temperature rise rate is 40-50°C / h; Preferably, the end point temperature of the preheating is 110-130°C; Preferably, the heating rate of the reaction is 20-30°C / h; Preferably, the terminal temperature of the reaction is 220-240°C.

8. The method according to claim 6 or 7, characterized in that: The molar ratio of the total feed amount of the diol to the dibasic acid is (1.01-1.5):1, preferably (1.07-1.13):1; Preferably, the feed rate of the diol in the secondary feed in step (2) is carried out using the following formula: Among them, v diol is the feed rate of diol for secondary feed (g / min); is the relative molecular weight of water; is the water extraction rate (g / min); M diol is the relative molecular weight of the diol; Preferably, when the acid value of the material obtained in step (3) is less than 30 mgKOH / g, a catalyst is added; Preferably, the amount of the catalyst in step (3) is 10-90 ppm, preferably 10-30 ppm, relative to the total amount of raw materials added; Preferably, after adding the catalyst in step (3), the method further comprises: when the acid value of the obtained material is less than 20 mgKOH / g, the alcohol separated from the alcohol vapor is collected into an alcohol storage tank; Preferably, when the acid value of the material obtained in step (3) is less than 0.2 mgKOH / g, the reaction is terminated.

9. A device system for preparing polyester polyols, characterized in that: The device system includes a reaction device and a separation and recovery unit that are connected; A pump assembly and a first valve are sequentially arranged on the feed pipeline connected to the reaction device; The separation and recovery unit comprises a packing tower, a condensing device, a separation device, a vacuum device, a water storage tank and an alcohol storage tank; The separation device is provided with a hydrophilic separation membrane according to any one of claims 1 to 3 or a hydrophilic separation membrane prepared by the preparation method according to claim 4 or 5; The reaction device is connected to the packing tower, the condensing device, and the separation device in sequence through pipelines; A flow component is provided on the pipeline connecting the packing tower and the condensing device, and the flow component is connected to the first valve; The outlet of the separation device is independently connected to the water storage tank, the alcohol storage tank, and the reaction device respectively; The vacuum device is independently connected to the water storage tank and the alcohol storage tank respectively.

10. The device system according to claim 9, characterized in that: A second valve is provided on the pipeline connecting the separation device and the water storage tank; Preferably, a third valve is provided on the pipeline connecting the water storage tank and the vacuum device; Preferably, a fourth valve is provided on the pipeline connecting the reaction device and the separation device; Preferably, a fifth valve is provided on the pipeline connecting the separation device and the alcohol storage tank; Preferably, a sixth valve is provided on the pipeline connecting the alcohol storage tank and the vacuum device.

Images