Synthesis method of phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin

Abstract

The invention discloses a synthesis method of phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin, and relates to the technical field of chemical raw material production. The synthesis method of the phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin comprises the following steps: dropwise adding a dichloromethane solution of methyl phosphoryl dichloride into a dichloromethane solution containing 4, 4 '-diaminodiphenyl sulfone and triethylamine, filtering, washing and drying by distillation to obtain an oligomer; dispersing the oligomer in 2-bromoethanol, and dropwise adding an aqueous solution of ethylene glycol to obtain an ethanol-terminated oligomer; and polymerizing the ethanol-terminated oligomer, fatty diol, phosphorus-containing polyester diol, phthalic anhydride and maleic anhydride, and diluting to obtain the phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin. The phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin prepared by the preparation method disclosed by the invention is excellent in flame retardant property, high in impact resistance and good in thermal stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical raw material production, in particular to a synthesis method of phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin. BACKGROUND

[0002] In recent years, fires have become increasingly frequent, and the economic losses caused by fires have also become increasingly serious. For high polymer materials widely used in daily life, the limiting oxygen index is generally 17%-20%, which is flammable, and it has great practical significance to endow it with flame retardance in many places. At present, flame-retardant high polymer materials and flame-retardant technology have become one of the research hotspots. In the prior art, flame-retardant high polymer materials refer to those that are not easy to burn or can self-extinguish when encountering fire. Such materials usually have high thermal stability and good flame retardance, can reduce the burning speed, reduce the possibility of flame propagation, and reduce the release of harmful smoke and gas in a fire. Flame-retardant high polymer materials are widely used in fields such as building, transportation, electronics and electrical appliances, and aerospace.

[0003] Unsaturated polyester resin has excellent process performance, electrical performance, corrosion resistance and mechanical properties, and is widely used in fields such as building, chemical industry, electrical appliances and medicine. However, the limiting oxygen index of general unsaturated polyester resin is only 19%, which is easy to burn, and a large amount of black smoke and toxic gas is generated during burning, which has an adverse effect on the application of unsaturated polyester resin. Therefore, it is urgent to improve the flame retardance of the resin. At present, the flame-retardant modification of unsaturated polyester resin can be divided into two ways: one is to add inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide and red phosphorus to modify the resin by blending, but this method has the disadvantages of large addition amount, poor thermal stability, easy hydrolysis under moisture, poor compatibility and the like, which reduces the comprehensive performance of the resin and cannot meet the strict requirements of high-end application fields such as electronics and electrical appliances; the other is to react with flame-retardant monomers with active groups to modify the unsaturated polyester resin, and introduce flame-retardant elements (such as phosphorus, nitrogen and sulfur) into the main chain of the resin. Although this method is beneficial to the balance of the comprehensive performance of the resin, the phosphorus-sulfur block is too rigid, the impact strength is reduced, and the addition of a toughening agent will dilute the flame-retardant elements and reduce the flame retardance. Therefore, it is urgent to develop a new type of halogen-free flame-retardant monomer to meet the demand for flame-retardant modification of unsaturated polyester. SUMMARY

[0004] The purpose of the present application is to provide a synthesis method of phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin, which solves the following technical problems:

[0005] The existing phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin has the problems of poor flame retardance and reduced impact strength of the unsaturated polyester due to the introduction of the phosphorus-sulfur block.

[0006] The object of the application can be achieved by the following technical solutions:

[0007] A synthesis method of a phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin, comprising the following steps:

[0008] A dichloromethane solution of methylphosphoryl dichloride is added dropwise to a dichloromethane solution containing 4,4'-diaminodiphenyl sulfone and triethylamine, filtered, washed and evaporated to dryness to obtain an oligomer;

[0009] The oligomer is dispersed in 2-bromoethanol, and an aqueous solution of ethylene glycol is added dropwise to obtain an ethanol-terminated oligomer;

[0010] The ethanol-terminated oligomer, a fatty diol, a phosphorus-containing polyester diol, phthalic anhydride and maleic anhydride are polymerized, and after dilution, a phosphorus-sulfur composite flame-retardant block modified unsaturated polyester resin is obtained.

[0011] Preferably, the molar ratio of the methylphosphoryl dichloride and the 4,4'-diaminodiphenyl sulfone is 1:1.05-1.15.

[0012] Preferably, the oligomer has the following structural formula:

[0013] ,

[0014] Wherein, m1 is in the range of 15-65.

[0015] Preferably, the molar ratio of the oligomer and the 2-bromoethanol is 1:1, and the molar ratio of the ethylene glycol and the oligomer is 1.05-1.1:1.

[0016] Preferably, the ethanol-terminated oligomer has the following structural formula:

[0017] ,

[0018] Wherein, m2 is in the range of 15-65.

[0019] Preferably, the molar ratio of the ethanol-terminated oligomer, the fatty diol, the phosphorus-containing polyester diol, phthalic anhydride and maleic anhydride is 1:0.8-1.2:0.25-0.45:1-1.2:0.8-1.

[0020] Preferably, the preparation method of the phosphorus-containing polyester diol at least comprises the following steps:

[0021] N,N-bis(2-hydroxyethyl) aminomethylene phosphoric acid diethyl ester, adipic acid, hexanediol and catalyst DBTDL are mixed, and the temperature is raised to 160°C for esterification reaction to obtain a phosphorus-containing polyester diol.

[0022] Preferably, the acid value of the phosphorus-containing polyester diol is 15-25 mg KOH / g, the hydroxyl value is 130-150 mg KOH / g, and the molar ratio of the N,N-bis(2-hydroxyethyl aminomethylene phosphoric acid diethyl ester), the adipic acid and the hexanediol is 0.6-0.9:0.9-1.2:0.7-1.

[0023] Preferably, the phosphorus-containing polyester diol has the following structural formula:

[0024] ,

[0025] wherein m3 is in the range of 2-5.

[0026] Preferably, the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin has the following structural formula:

[0027] ,

[0028] wherein n is in the range of 80-150, R1 is an ethanol-terminated oligomer, and R2 is a phosphorus-containing polyester diol.

[0029] Advantages of the present application:

[0030] The present application provides a synthesis method of a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin. A dichloromethane solution of methyl phosphorodichloridate is reacted with a dichloromethane solution containing 4,4'-diaminodiphenyl sulfone and triethylamine to obtain an oligomer after purification, and the oligomer is ethanol-terminated. The ethanol-terminated oligomer is polymerized with a fatty diol, a phosphorus-containing polyester diol, phthalic anhydride and maleic anhydride, and after dilution, a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin is obtained. The phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin prepared in the present application is a random copolymer. The double bond of maleic anhydride provides a crosslinking active site, and the ethanol-terminated oligomer is introduced as a phosphorus-sulfur block, which has good flame-retardant performance. The phosphorus-containing polyester diol is introduced as a phosphorus-nitrogen synergistic polyester soft segment, which further improves the flame-retardant performance and the impact resistance of the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin. The phosphorus-sulfur flame-retardant hard segment and the phosphorus-nitrogen flame-retardant soft segment are dispersed in the polyester main chain, solving the problem that flame retardance and mechanical properties are difficult to be balanced. All reagents used in the synthesis method provided by the present application and the synthesis method are common reagents and mature synthesis methods, and the industrialization difficulty is low.

[0031] In the preparation process of the oligomer, the two acyl chloride groups of methyl phosphorodichloridate are subjected to nucleophilic substitution reaction with the two amino groups of 4,4'-diaminodiphenyl sulfone to generate phosphoramide bond and primary amine two end groups, and a phosphorus-nitrogen bond-containing oligomer is obtained. In the preparation process of the ethanol end-capped, the amino group can be converted into N-ethanol group through substitution reaction of bromoethanol and the primary amine, and the phosphorus oxychloride can be converted into hydroxyl phosphate through alcoholysis of ethylene glycol and the acyl chloride, so that the two end groups are both converted into hydroxyl groups, and then the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin is prepared by polymerization, which can effectively protect the phosphorus and sulfur elements in the resin and improve the flame-retardant performance of the resin system. The oligomer prepared in the application introduces phosphorus-amine bond, and the phosphorus is mainly concentrated in the sulfide block.

[0032] In the application, N,N-bis(2-hydroxyethyl) aminomethylene phosphoric acid diethyl ester, adipic acid and hexanediol are used as raw materials to design and synthesize phosphorus-containing polyester diols, which are used as soft segment chain extenders in the polymerization of the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, and the hydroxyl value is matched with the resin system, so that the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin can directly participate in polycondensation. In the polymerization process, N,N-bis(2-hydroxyethyl) aminomethylene phosphoric acid diethyl ester introduces phosphorus and nitrogen groups into the polyester main chain, and the flexible segment can be used as a "soft segment" to increase the flexibility and impact resistance of the resin, the chain extension reaction can increase the molecular weight of the resin, improve the tensile strength and elastic modulus, and avoid the brittleness problem caused by the introduction of phosphorus-sulfur block. At the same time, the phosphorus and nitrogen groups of the phosphorus-containing polyester diol are combined with the unsaturated polyester segment through chemical bond, the phosphorus and nitrogen groups are uniformly distributed along the polyester chain, the compatibility with the matrix is enhanced, the material uniformity is improved, the content of phosphorus and nitrogen can be adjusted, the flame-retardant grade is optimized, and the processing fluidity of the resin is maintained.

[0033] The phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin prepared in the application can adjust the proportion of phosphorus-sulfur elements in the resin, increase the proportion of phosphorus by increasing the reaction sites of phosphorus oxychloride and amine by replacing part of 4,4'-diaminodiphenyl sulfone with ethylenediamine or diphenylamine, and increase the proportion of sulfur by replacing methyl phosphorodichloridate with terephthaloyl chloride and the like to introduce more sulfur bonds. The phosphorus-containing polyester diol can also be synthesized independently, the phosphorus-nitrogen ratio, molecular weight and end group functional group can be accurately controlled, and efficient phosphorus-sulfur-nitrogen ternary synergistic flame retardation can be realized. The unsaturated polyester resin prepared in the application has a large proportion of phosphorus and sulfur in the segment, has good flame-retardant performance, and the proportion of phosphorus and sulfur can be accurately adjusted in the synthesis stage, so that a series of unsaturated polyester resins with different flame-retardant performance and flame-retardant characteristics can be obtained to meet the flame-retardant requirements of different resin products, and the applicability of the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin is improved. In the actual production process, the by-products sodium bromide and ethylene glycol / diethylene glycol mixture can be sold separately after distillation and separation, which significantly improves the utilization rate of the reactants and reduces the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0035] Fig. 1 1H NMR spectrum of the oligomer prepared in an embodiment;

[0036] Fig. 2 13C NMR spectrum of the oligomer prepared in an embodiment;

[0037] Fig. 3 Fourier infrared spectrum analysis spectrum of the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin prepared in an embodiment. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the protection scope of the present application.

[0039] The preparation method of the phosphorus-containing polyester diol in Embodiment 1 comprises the following steps:

[0040] 0.7 mol of N,N-bis(2-hydroxyethyl)aminomethylene phosphonic acid diethyl ester, 1 mol of adipic acid, 0.8 mol of hexanediol and 0.5 wt% of total solid content of catalyst DBTDL are put into a three-necked flask equipped with a stirrer, a condenser and a thermometer, and the oil bath is gradually heated to 160℃ for esterification. Water is removed by vacuum every 30 min of reaction, and the acid value of the reaction system is measured. When the acid value is reduced to about 20 mg KOH / g, the reaction is ended, and the product is discharged. The obtained phosphorus-containing polyester diol has an acid value of 20 mg KOH / g and a hydroxyl value of 140 mg KOH / g.

[0041] The preparation method of the phosphorus-containing polyester diol in Embodiment 2 comprises the following steps:

[0042] Put 0.75 mol of N,N-bis(2-hydroxyethyl) aminomethylene phosphonic acid diethyl ester, 1 mol of adipic acid, 0.85 mol of hexanediol and 0.5 wt% of total solid content into a three-necked flask equipped with a stirrer, a condenser and a thermometer, and gradually heat the oil bath to 160°C to perform esterification, remove water by vacuum every 30 min, and measure the acid value of the reaction system; when the acid value is reduced to about 20 mg KOH / g, the reaction is completed, the product is discharged, and a phosphorus-containing polyester diol with an acid value of 18 mg KOH / g and a hydroxyl value of 148 mg KOH / g is obtained.

[0043] Example 3: A synthesis method of a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, at least comprising the following steps:

[0044] Drop the dichloromethane solution of methyl phosphorodichloridate into the dichloromethane solution of 4,4'-diaminodiphenyl sulfone and triethylamine, wherein the molar ratio of methyl phosphorodichloridate to 4,4'-diaminodiphenyl sulfone is 1:1.05, after the drop is completed, heat to 60°C for 2h, after the reaction is completed, cool down, remove triethylamine hydrochloride by filtration, and sequentially wash the filtrate with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine and deionized water, and evaporate to dryness to obtain an oligomer.

[0045] Disperse the above oligomer in equimolar amount of 2-bromoethanol under nitrogen protection, mix thoroughly, and then heat at 80°C for 4h. Then drop the aqueous solution of ethylene glycol, monitor the concentration of bromoethanol by HPLC, continue to drop when the bromoethanol is completely consumed, keep the molar ratio of ethylene glycol to oligomer at 1.05:1, and continue to react for 4h. After the reaction is completed, stop heating, cool to room temperature, and then add 10% sodium hydroxide solution to precipitate the product to obtain an ethanol-terminated oligomer.

[0046] Put the above ethanol-terminated oligomer, the phosphorus-containing polyester diol prepared in Example 1, ethylene glycol, phthalic anhydride and maleic anhydride according to the molar ratio of 1:0.35:1:1.15:1 into a reaction kettle together with an auxiliary, pass nitrogen for 15 min to ensure that the kettle is in an inert environment, and finally react at 200°C for 15h, take samples for detection, cool to 90°C when the acid value reaches 30 mg KOH / g, and after the reaction is completed, pump the cooled semi-finished product into a dilution kettle to mix and dilute with styrene diluent, filter and package after product detection, and finally obtain the finished unsaturated polyester resin.

[0047] Example 4: A synthesis method of a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, at least comprising the following steps:

[0048] The dichloromethane solution of methyl phosphorodichloridate was added dropwise into the dichloromethane solution of 4,4'-diaminodiphenyl sulfone and triethylamine, wherein the molar ratio of methyl phosphorodichloridate and 4,4'-diaminodiphenyl sulfone was 1:1.05, after the dropwise addition was completed, the temperature was raised to 60°C and reacted for 2h, after the reaction was completed, the temperature was lowered, the triethylamine hydrochloride was removed by filtration, and the filtrate was washed with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine and deionized water in sequence, and was evaporated to dryness to obtain an oligomer.

[0049] The above oligomer was dispersed in an equal molar amount of 2-bromoethanol under nitrogen protection, mixed thoroughly, and then heated at 80°C for 4h. Then an aqueous solution of ethylene glycol was added dropwise, and the concentration of bromoethanol was monitored by HPLC. When the bromoethanol was completely consumed, the dropwise addition was continued, and the molar ratio of ethylene glycol to oligomer was maintained at 1.05:1, and the reaction was continued for 4h. After the reaction was completed, the heating was stopped, and the product was precipitated after the temperature was cooled to room temperature by adding a 10% sodium hydroxide solution to obtain an ethanol-terminated oligomer.

[0050] The above ethanol-terminated oligomer, the phosphorus-containing polyester diol prepared in Example 2, ethylene glycol, phthalic anhydride and maleic anhydride were added into a reaction kettle according to a molar ratio of 1:0.35:1:1.15:1, and an auxiliary was added. Nitrogen was passed for 15min to ensure that the kettle was in an inert environment, and then the reaction was carried out at 200°C for 15h. After the acid value reached 30mg KOH / g, the temperature was lowered to 90°C. After the reaction was completed, the semi-finished product after the temperature was lowered was pumped into a dilution kettle and mixed with a styrene diluent for dilution. After the finished product was detected, the product was filtered and packaged to obtain a finished unsaturated polyester resin.

[0051] Example 5 A synthesis method of a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, at least comprising the following steps:

[0052] The dichloromethane solution of methyl phosphorodichloridate was added dropwise into the dichloromethane solution of 4,4'-diaminodiphenyl sulfone and triethylamine, wherein the molar ratio of methyl phosphorodichloridate and 4,4'-diaminodiphenyl sulfone was 1:1.1, after the dropwise addition was completed, the temperature was raised to 60°C and reacted for 2h, after the reaction was completed, the temperature was lowered, the triethylamine hydrochloride was removed by filtration, and the filtrate was washed with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine and deionized water in sequence, and was evaporated to dryness to obtain an oligomer.

[0053] The above oligomer was dispersed in an equal molar amount of 2-bromoethanol under nitrogen protection, mixed thoroughly, and then heated at 80°C for 4h. Then an aqueous solution of ethylene glycol was added dropwise, and the concentration of bromoethanol was monitored by HPLC. When the bromoethanol was completely consumed, the dropwise addition was continued, and the molar ratio of ethylene glycol to oligomer was maintained at 1.1:1, and the reaction was continued for 4h. After the reaction was completed, the heating was stopped, and the product was precipitated after the temperature was cooled to room temperature by adding a 10% sodium hydroxide solution to obtain an ethanol-terminated oligomer.

[0054] The above ethanol-terminated oligomer, phosphorus-containing polyester diol prepared in Example 1, ethylene glycol, phthalic anhydride and maleic anhydride were added into a reaction kettle according to a molar ratio of 1:0.45:0.8:1.15:1 together with an auxiliary, nitrogen was passed for 15 min to ensure that the kettle was in an inert environment, and finally reacted at 200°C for 15 h. Sampling detection was performed, and after the acid value reached 30 mg KOH / g, the temperature was lowered to 90°C. After the reaction was completed, the semi-finished product after cooling was pumped into a dilution kettle and mixed with a styrene diluent for dilution. After product detection, filtration and packaging were performed, and finally the finished unsaturated polyester resin was obtained.

[0055] Example 6 A synthesis method of a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, at least comprising the following steps:

[0056] Methylphosphoryl dichloride in dichloromethane was added dropwise into a dichloromethane solution of 4,4'-diaminodiphenyl sulfone and triethylamine, wherein the molar ratio of methylphosphoryl dichloride and 4,4'-diaminodiphenyl sulfone was 1:1.1. After the dropwise addition was completed, the temperature was raised to 60°C and reacted for 2 h. After the reaction was completed, the temperature was lowered, and triethylamine hydrochloride was removed by filtration. The filtrate was washed with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine and deionized water in sequence, and then evaporated to dryness to obtain an oligomer.

[0057] The above oligomer was dispersed in an equal molar amount of 2-bromoethanol under nitrogen protection, and after thorough mixing, heated at 80°C for 4 h. Then, an aqueous solution of ethylene glycol was added dropwise, and the concentration of bromoethanol was monitored by HPLC. When the bromoethanol was completely consumed, the dropwise addition was continued, and the molar ratio of ethylene glycol to oligomer was maintained at 1.1:1. The reaction was continued for 4 h. After the reaction was completed, the heating was stopped, and after cooling to room temperature, 10% sodium hydroxide solution was added to precipitate the product, and an ethanol-terminated oligomer was obtained.

[0058] The above ethanol-terminated oligomer, phosphorus-containing polyester diol prepared in Example 2, ethylene glycol, phthalic anhydride and maleic anhydride were added into a reaction kettle according to a molar ratio of 1:0.45:0.8:1.15:1 together with an auxiliary, nitrogen was passed for 15 min to ensure that the kettle was in an inert environment, and finally reacted at 200°C for 15 h. Sampling detection was performed, and after the acid value reached 30 mg KOH / g, the temperature was lowered to 90°C. After the reaction was completed, the semi-finished product after cooling was pumped into a dilution kettle and mixed with a styrene diluent for dilution. After product detection, filtration and packaging were performed, and finally the finished unsaturated polyester resin was obtained.

[0059] Comparative Example 1 A synthesis method of a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, at least comprising the following steps:

[0060] The dichloromethane solution of methyl phosphonic dichloride was added dropwise into the dichloromethane solution of 4,4'-diaminodiphenyl sulfone and triethylamine, wherein the molar ratio of methyl phosphonic dichloride and 4,4'-diaminodiphenyl sulfone was 1:1.05, after the dropwise addition was completed, the temperature was raised to 60°C and reacted for 2h, after the reaction was completed, the temperature was lowered, the triethylamine hydrochloride was removed by filtration, and the filtrate was washed with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine and deionized water in sequence, and was evaporated to dryness to obtain an oligomer.

[0061] The above oligomer was dispersed in an equal molar amount of 2-bromoethanol under nitrogen protection, mixed thoroughly, and then heated at 80°C for 4h. Then an aqueous solution of ethylene glycol was added dropwise, and the concentration of bromoethanol was monitored by HPLC. When the bromoethanol was completely consumed, the dropwise addition was continued, the molar ratio of ethylene glycol to oligomer was maintained at 1.05:1, and the reaction was continued for 4h. After the reaction was completed, the heating was stopped, the temperature was cooled to room temperature, and a 10% sodium hydroxide solution was added to precipitate the product to obtain an ethanol-capped oligomer.

[0062] The above ethanol-capped oligomer, aliphatic diol, phthalic anhydride and maleic anhydride were added into a reaction kettle according to a molar ratio of 1:1:1.15:1 together with an auxiliary, nitrogen was passed for 15min to ensure that the kettle was in an inert environment, and finally reacted at 200°C for 15h. Sampling detection was performed, the temperature was lowered to 90°C after the acid value reached 30mg KOH / g, and after the reaction was completed, the semi-finished product after cooling was pumped into a dilution kettle and mixed with a styrene diluent for dilution. After product detection, filtration and packaging were performed, and finally the unsaturated polyester resin was obtained.

[0063] Comparative Example 2: A synthesis method of a phosphorus-nitrogen composite flame-retardant block-modified unsaturated polyester resin, at least comprising the following steps:

[0064] The dichloromethane solution of methyl phosphonic dichloride was added dropwise into the dichloromethane solution of 4,4'-diaminodiphenyl sulfone and triethylamine, wherein the molar ratio of methyl phosphonic dichloride and 4,4'-diaminodiphenyl sulfone was 1:1.05, after the dropwise addition was completed, the temperature was raised to 60°C and reacted for 2h, after the reaction was completed, the temperature was lowered, the triethylamine hydrochloride was removed by filtration, and the filtrate was washed with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine and deionized water in sequence, and was evaporated to dryness to obtain an oligomer.

[0065] The above oligomer was dispersed in an equal molar amount of 2-bromoethanol under nitrogen protection, mixed thoroughly, and then heated at 80°C for 4h. Then an aqueous solution of ethylene glycol was added dropwise, and the concentration of bromoethanol was monitored by HPLC. When the bromoethanol was completely consumed, the dropwise addition was continued, the molar ratio of ethylene glycol to oligomer was maintained at 1.05:1, and the reaction was continued for 4h. After the reaction was completed, the heating was stopped, the temperature was cooled to room temperature, and a 10% sodium hydroxide solution was added to precipitate the product to obtain an ethanol-capped oligomer.

[0066] The above-mentioned ethanol-terminated oligomer, phosphorus-containing polyester diol prepared in Example 1, phthalic anhydride and maleic anhydride are added into a reaction kettle according to a molar ratio of 1:0.35:1.15:1, and an auxiliary is added. Nitrogen is passed for 15 min to ensure that the kettle is in an inert environment. Finally, the reaction is carried out at 200℃ for 15h. After the acid value reaches 30mg KOH / g, the temperature is reduced to 90℃. After the reaction is completed, the semi-finished product after cooling is pumped into a dilution kettle and mixed with a styrene diluent for dilution. After product detection, filtration and packaging, the final product, an unsaturated polyester resin, is obtained.

[0067] Performance detection

[0068] Impact strength: the impact strength of the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin prepared in the application is tested according to the method specified in GB / T2567-2008. The test results are shown in Table 1.

[0069] Oxygen index test: the oxygen index (OI) refers to the lowest oxygen concentration required for a material to just maintain a burning state under specified test conditions. The prepared sample is tested using a ZR-01 oxygen index tester from Qingdao Shanfeng Instrument Co., Ltd. According to the GB / T2406-2009 standard, the total flow rate of the mixed gas is controlled at 17-21L / min, and the sample size is 150×10×4mm 3 . The top surface ignition method is used, the sample is ignited, and the burning time and the observed burning length are recorded. The sample is considered to be in a burning state if the burning time does not exceed 180s and the burning length does not exceed 50mm of the top end of the sample. The flow rate ratio of nitrogen and oxygen is adjusted so that the lowest oxygen concentration required for the material to just maintain a burning state is the measured oxygen index. According to the test standard GB / T2406-2009, a resin with an oxygen index less than 22 is considered to be flammable, a resin with an oxygen index between 22 and 27 is considered to be self-extinguishing, and a resin with an oxygen index greater than 27 is considered to be difficult to burn. The test results are shown in Table 1.

[0070] Vertical burning test: the prepared sample is tested using a ZR-02 horizontal and vertical burning tester from Qingdao Shanfeng Instrument Co., Ltd. The vertical burning performance of the sample is tested according to the GB / T2048-2008 standard. The sample size is 150×13×4mm3, the ignition time is 10s, and the corresponding UL-94 flame retardant grade is measured. The test results are shown in Table 1.

[0071] Stability test: the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin prepared in Examples 1-3 is placed and aged, and then experimental pieces of the same size are prepared. The corresponding UL-94 flame retardant grade is measured. The aging treatment includes placing the prepared phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin in an environment at 50℃ for 24h, 72h and 120h. The test results are shown in Table 1.

[0072] Table 1: Example, comparative example test specimen performance test data statistics table

[0073]

[0074] From Table 1 and Figs. 1-3 It can be seen that the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin prepared in Examples 3-6 has high sulfur and phosphorus content, excellent flame-retardant properties, high impact resistance, and excellent anti-aging properties, and can maintain excellent flame-retardant properties after long-term storage, and the flame-retardant properties do not decrease under high-temperature storage conditions, and has extremely high thermal stability. The impact strength of Comparative Example 1 is low because it does not contain a phosphorus-containing polyester diol, but the flame-retardant properties are still good. The flame-retardant properties of Comparative Example 2 decrease, the oxygen index is low, and the impact strength is also low because it does not contain a fatty diol.

[0075] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example", and the like means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0076] The above describes one embodiment of the present application in detail, but the content described is only a preferred embodiment of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made in the scope of the present application should still be included in the scope of the present patent.

Claims

1. A method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, characterized in that: The following steps are involved: A dichloromethane solution of methylphosphoryl dichloride was added dropwise to a dichloromethane solution containing 4,4'-diaminodiphenyl sulfone and triethylamine, and the mixture was filtered, washed and evaporated to dryness to obtain an oligomer; Dispersing the oligomer in 2-bromoethanol, and adding dropwise an aqueous solution of ethylene glycol to obtain an ethanol-terminated oligomer; The ethanol-terminated oligomer, aliphatic diol, phosphorus-containing polyester diol, phthalic anhydride and maleic anhydride are polymerized and diluted to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin.

2. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: The molar ratio of the methyl phosphoryl dichloride to the 4,4'-diaminodiphenyl sulfone is 1:1.05-1.

15.

3. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: The structural formula of the oligomer is as follows: ， The value range of m1 is 15-65.

4. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: The molar ratio of the oligomer to the 2-bromoethanol is 1:1, and the molar ratio of the ethylene glycol to the oligomer is 1.05-1.1:

1.

5. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: The structural formula of the ethanol-terminated oligomer is as follows: ， The value range of m2 is 15-65.

6. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: The molar ratio of ethanol-terminated oligomer: fatty diol: phosphorus-containing polyester diol: phthalic anhydride: maleic anhydride is 1:0.8-1.2:0.25-0.45:1-1.2:0.8-1.

7. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: The preparation method of the phosphorus-containing polyester diol comprises at least the following steps: N,N-bis(2-hydroxyethyl)aminomethylene phosphonic acid diethyl ester, adipic acid, hexanediol and catalyst DBTDL were mixed and heated to 160° C. for esterification reaction to obtain phosphorus-containing polyester diol.

8. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 7, characterized in that: The phosphorus-containing polyester diol has an acid value of 15-25 mg KOH / g and a hydroxyl value of 130-150 mg KOH / g. The molar ratio of the N,N-bis(2-hydroxyethylaminomethylenephosphonic acid) diethyl ester, the adipic acid, and the hexanediol is 0.6-0.9:0.9-1.2:0.7-1.

9. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: The structural formula of the phosphorus-containing polyester diol is as follows: ， The value range of m3 is 2-5.

10. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: The structural formula of the phosphorus-sulfur composite flame retardant block-modified unsaturated polyester resin is as follows: ， The value of n ranges from 80 to 150, R1 is an ethanol-terminated oligomer, and R2 is a phosphorus-containing polyester diol.

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