A phosphorus-sulfur block unsaturated polyester resin and its synthesis method

Abstract

The present application provides a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin and a synthesis method thereof. The resin comprises a dichloromethane solution A and a dichloromethane solution B, followed by purification, to obtain an oligomer C. The oligomer C is then subjected to an ethanol end-capping treatment to obtain an ethanol-terminated oligomer D. Finally, the ethanol-terminated oligomer D, a fatty diol, phthalic anhydride, maleic anhydride, and an auxiliary agent are polymerized and purified to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin. The resin comprises a large proportion of phosphorus and sulfur elements, and has excellent flame retardant properties. The phosphorus and sulfur content in the resin can be precisely controlled during the synthesis stage, thereby improving the diversity and applicability of the resin product and meeting the usage needs of different customer groups. The resin has the advantages of low industrialization difficulty, low implementation cost, and easy promotion and implementation.

Description

Technical Field

[0001] The present application belongs to the technical field of chemical raw material production, and specifically relates to a phosphorus-sulfur block unsaturated polyester resin and a synthesis method thereof. Background Art

[0002] In the prior art, flame-retardant polymer materials refer to polymer materials that are difficult to burn or can extinguish themselves when exposed to flames. These materials generally have high thermal stability and good flame retardancy, which can reduce the combustion rate, reduce the possibility of flame spread, and reduce the release of harmful smoke and gases in a fire. Flame-retardant polymer materials are widely used in fields such as construction, transportation, electronics and electrical engineering, and aerospace. In recent years, fires have become increasingly frequent, and the economic losses caused by fires have also become increasingly serious.

[0003] In the prior art, the polymer materials widely used in daily life generally have a limiting oxygen index of 17%-20% and are flammable. The existing flame retardant modification method for polymer materials is usually physical modification, that is, mixing halogen flame retardants into the resin matrix. In actual implementation, due to the mixing of halogen flame retardants, the polymer materials will produce a large amount of toxic gases and smoke during the combustion process. With the advancement of science and technology and the improvement of people's environmental awareness, a number of environmental protection laws and regulations have been promulgated. Halogen flame retardants are currently on the verge of being eliminated and are not in line with the scientific concept of green chemistry. On the other hand, after the polymer materials are mixed with halogen flame retardants, filler migration and agglomeration will occur during long-term use, which will not only cause the flame retardant components to fail and significantly reduce the flame retardant properties of the resin, but also reduce the mechanical properties of the resin system. Therefore, improvements are urgently needed. Summary of the Invention

[0004] The present application aims to solve the technical problems in the prior art that polymer materials widely used in daily life generally have a limiting oxygen index of 17%-20%, are highly thermally sensitive, and are easily combustible when exposed to fire. On the one hand, this poses a major safety hazard and requires flame retardant modification to meet user needs. On the other hand, existing flame retardants are mostly halogen flame retardants and are mostly mixed into the resin matrix in the form of fillers, resulting in poor resin system stability. During the resin combustion process, a large amount of toxic gases will be generated, which is not in line with the concept of green chemistry. A phosphorus-sulfur block unsaturated polyester resin is proposed;

[0005] In order to solve the technical problem raised in this application, this application also provides a method for preparing a phosphorus-sulfur block unsaturated polyester resin.

[0006] The present application adopts the following scheme, a method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, comprising the following steps:

[0007] Step 101. Add dichloromethane solution A dropwise to dichloromethane solution B, and react in a water bath at 50°C-70°C and 500-1200 rpm for 1-3 hours to obtain crude oligomeric product C.

[0008] Wherein, dichloromethane solution A is a dichloromethane solution of methylphosphoryl dichloride, and dichloromethane solution B is a dichloromethane solution of 4,4'-diaminodiphenyl sulfone and triethylamine;

[0009] Step 102. The crude oligomer C obtained after filtering the liquid phase in step 101 is washed sequentially with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine, and deionized water, and then evaporated to dryness to obtain oligomer C;

[0010] Step 103. Disperse the oligomer C obtained in step 102 in 2-bromoethanol, then add an aqueous solution of ethylene glycol dropwise thereto. React in a water bath at 70°C-90°C for 1-10 hours, cool to room temperature, and add a 10% sodium hydroxide solution to precipitate the product, thereby obtaining ethanol-terminated oligomer D.

[0011] Step 104. Add the ethanol-terminated oligomer D, fatty diol, phthalic anhydride, maleic anhydride and additives prepared in step 103 into a reactor, and react in an inert gas environment at 150°C-220°C for 15h-20h to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin semi-finished product. Then transfer it to a dilution kettle for dilution, and then filter and package it in sequence to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin finished product.

[0012] In one embodiment, in step 101, the dichloromethane solution A is a solution prepared by mixing methylphosphoryl dichloride and dichloromethane solution in a mass ratio of 4:5;

[0013] The dichloromethane solution B is a solution prepared by mixing 4,4'-diaminodiphenyl sulfone, triethylamine, and dichloromethane solution in a mass ratio of 4:3:5.

[0014] During actual implementation, if it is necessary to adjust the proportion of phosphorus-sulfur elements in the resin, for example, if the phosphorus ratio needs to be increased, part of the 4,4'-diaminodiphenyl sulfone can be replaced with ethylenediamine or benzidine, and if the sulfur ratio needs to be increased, methylphosphoryl dichloride can be replaced with terephthaloyl chloride, etc. The unsaturated polyester resin prepared by this scheme has a large proportion of phosphorus and sulfur in the chain segments, good flame retardant properties, and their proportions can be accurately adjusted during the synthesis stage to obtain a series of unsaturated polyester resins with different flame retardant properties and flame retardant characteristics, so as to meet the flame retardant requirements of different resin products and improve the applicability of phosphorus-sulfur composite flame retardant block-modified unsaturated polyester resins.

[0015] In actual implementation, the by-products sodium bromide and the ethylene glycol / diethylene glycol mixture in steps 101 to 104 can be sold separately after being separated by distillation, which significantly improves the utilization rate of the reactants.

[0016] In one embodiment, in step 102, the structural formula of oligomer C is as follows:

[0017]

[0018] The value range of n is 1500-2650.

[0019] In step 102, oligomer C is synthesized as follows:

[0020]

[0021] In one embodiment, in step 103, under a nitrogen atmosphere, the oligomer C obtained in step 102 is dispersed in 2-bromoethanol at a molar ratio of 1:1, and then an aqueous solution of ethylene glycol is added dropwise thereto. During the reaction, the concentration of 2-bromoethanol is monitored by HPLC.

[0022] In one embodiment, in step 103, during the reaction of oligomer C, the concentration of 2-bromoethanol is monitored by HPLC, and the molar ratio of ethylene glycol to oligomer C is maintained at 1.05-1.1:1.

[0023] In one embodiment, in step 103, the structural formula of the ethanol-terminated oligomer D is as follows:

[0024]

[0025] The value range of n is 1680-2100.

[0026] In step 103, the synthesis equation of the ethanol-terminated oligomer D is as follows:

[0027]

[0028] During the actual implementation process, during the preparation of oligomer C in step 102, oligomer C may contain two terminal groups, one of which is a phosphorus oxychloride group and the other is a primary amine. The amino group can be converted into an N-ethanol group through the substitution reaction of bromoethanol and the primary amine; the phosphorus oxychloride can be converted into a hydroxyl phosphate through the alcoholysis of ethylene glycol and acyl chloride, thereby converting both terminal groups into hydroxyl groups, and then polyaddition is performed to prepare a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, which can effectively protect the phosphorus and sulfur elements in the resin and improve the flame retardant properties of the resin system.

[0029] In one embodiment, in step 104, the molar ratio of the ethanol-terminated oligomer D, the fatty diol, the phthalic anhydride, and the maleic anhydride is 1.05:1.25:1.15:1.

[0030] In one embodiment, in step 104, during the reaction, samples are taken from the reaction system every 30 minutes to detect the acid value in the system. When the acid value of the reaction system reaches 30 mgKOH / g, the reaction system is cooled to 90° C. and the reaction is terminated.

[0031] In order to solve the technical problem raised in this application, this application also provides a phosphorus-sulfur composite flame retardant block modified unsaturated polyester resin, which is prepared by the above-mentioned synthesis method of a phosphorus-sulfur composite flame retardant block modified unsaturated polyester resin.

[0032] In one embodiment, the phosphorus-sulfur composite flame retardant block-modified unsaturated polyester resin has the following structural formula:

[0033]

[0034] The value range of m is 1800-3500, and the value range of n is 1800-2000.

[0035] Compared with the prior art, this application has the following beneficial effects:

[0036] The present application provides a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin and a synthesis method thereof. The resin is prepared by reacting a dichloromethane solution A with a dichloromethane solution B and refining the resultant to obtain an oligomer C. The oligomer C is then end-capped with ethanol to obtain an ethanol-end-capped oligomer D. Finally, the ethanol-end-capped oligomer D, a fatty diol, phthalic anhydride, maleic anhydride, and an auxiliary agent are polymerized and refined to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin. The resin contains a relatively large proportion of phosphorus and sulfur elements and has excellent flame retardant properties. The content of phosphorus and sulfur elements in the resin can be precisely controlled during the synthesis stage, thereby improving the diversity and applicability of the resin product and meeting the usage needs of different customer groups. The resin has the advantages of low industrialization difficulty, low implementation cost, and easy promotion and implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the 1H NMR spectrum of oligomer C prepared in Example 3 of the present application;

[0038] Figure 2 This is the 13C NMR spectrum of oligomer C prepared in Example 3 of the present application. DETAILED DESCRIPTION

[0039] The present technical solution is further explained with reference to Examples 1-3.

[0040] Example 1

[0041] (1) The synthesis method of phosphorus-sulfur composite flame retardant block modified unsaturated polyester resin comprises the following steps:

[0042] Step 101. Add dichloromethane solution A dropwise into dichloromethane solution B, and react in a water bath at 69.5°C and 750 rpm for 1 hour to obtain crude oligomeric product C.

[0043] Wherein, dichloromethane solution A is a solution prepared by mixing methylphosphoryl dichloride and dichloromethane solution in a mass ratio of 4:5;

[0044] Dichloromethane solution B is a solution prepared by mixing 4,4'-diaminodiphenyl sulfone, triethylamine, and dichloromethane solution in a mass ratio of 4:3:5;

[0045] Step 102. The crude oligomer C obtained after filtering the liquid phase in step 101 is washed sequentially with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine, and deionized water, and then evaporated to dryness to obtain oligomer C;

[0046] Step 103. Under a nitrogen atmosphere, the oligomer C obtained in step 102 was dispersed in 2-bromoethanol at a molar ratio of 1:1. An aqueous solution of ethylene glycol was then added dropwise thereto. During the reaction, the concentration of 2-bromoethanol was monitored by HPLC in a water bath at 70°C to maintain a molar ratio of ethylene glycol to oligomer C of 1.05:1. The reaction was continued for 8.5 hours, and the mixture was cooled to room temperature. A 10% sodium hydroxide solution was then added to precipitate the product, thereby obtaining ethanol-terminated oligomer D.

[0047] Step 104. The ethanol-terminated oligomer D, fatty diol, phthalic anhydride, maleic anhydride and auxiliary agents prepared in step 103 are added to a reactor, and the mixture is reacted at 157° C. under a nitrogen atmosphere for 19 hours. During the reaction, samples are taken from the reaction system every 30 minutes to detect the acid value in the system. When the acid value of the reaction system reaches 30 mgKOH / g, the reaction system is cooled to 90° C. and the reaction is terminated to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin semi-finished product. The semi-finished product is then transferred to a dilution kettle for dilution, and then filtered and packaged to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin finished product.

[0048] The molar ratio of the ethanol-terminated oligomer D, the fatty diol, the phthalic anhydride and the maleic anhydride is 1.05:1.25:1.15:1.

[0049] Example 2

[0050] (1) The synthesis method of phosphorus-sulfur composite flame retardant block modified unsaturated polyester resin comprises the following steps:

[0051] Step 101. Add dichloromethane solution A dropwise into dichloromethane solution B, and react in a water bath at 60°C and 500-1200 rpm for 2 h to obtain crude oligomeric product C.

[0052] Wherein, dichloromethane solution A is a solution prepared by mixing methylphosphoryl dichloride and dichloromethane solution in a mass ratio of 4:5;

[0053] Dichloromethane solution B is a solution prepared by mixing 4,4'-diaminodiphenyl sulfone, triethylamine, and dichloromethane solution in a mass ratio of 4:3:5;

[0054] Step 102. The crude oligomer C obtained after filtering the liquid phase in step 101 is washed sequentially with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine, and deionized water, and then evaporated to dryness to obtain oligomer C;

[0055] Step 103. Under a nitrogen atmosphere, the oligomer C obtained in step 102 was dispersed in 2-bromoethanol at a molar ratio of 1:1. An aqueous solution of ethylene glycol was then added dropwise thereto. During the reaction, the concentration of 2-bromoethanol was monitored by HPLC in a water bath at 80°C to maintain a molar ratio of ethylene glycol to oligomer C of 1.07:1. After reacting for 5 hours, the mixture was cooled to room temperature and a 10% sodium hydroxide solution was added to precipitate the product, thereby obtaining ethanol-terminated oligomer D.

[0056] Step 104. The ethanol-terminated oligomer D, fatty diol, phthalic anhydride, maleic anhydride and auxiliary agents prepared in step 103 are added to a reactor, and the mixture is reacted at 185° C. under a nitrogen atmosphere for 18 hours. During the reaction, samples are taken from the reaction system every 30 minutes to detect the acid value in the system. When the acid value of the reaction system reaches 30 mgKOH / g, the reaction system is cooled to 90° C. and the reaction is terminated to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin semi-finished product. The semi-finished product is then transferred to a dilution kettle for dilution, and then filtered and packaged to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin finished product.

[0057] The molar ratio of the ethanol-terminated oligomer D, the fatty diol, the phthalic anhydride and the maleic anhydride is 1.05:1.25:1.15:1.

[0058] Example 3

[0059] (1) The synthesis method of phosphorus-sulfur composite flame retardant block modified unsaturated polyester resin comprises the following steps:

[0060] Step 101. Add dichloromethane solution A dropwise into dichloromethane solution B, and react in a water bath at 55°C and 1200 rpm for 3 hours to obtain crude oligomeric product C.

[0061] Wherein, dichloromethane solution A is a solution prepared by mixing methylphosphoryl dichloride and dichloromethane solution in a mass ratio of 4:5;

[0062] Dichloromethane solution B is a solution prepared by mixing 4,4'-diaminodiphenyl sulfone, triethylamine, and dichloromethane solution in a mass ratio of 4:3:5;

[0063] Step 102. The crude oligomer C obtained after filtering the liquid phase in step 101 is washed sequentially with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine, and deionized water, and then evaporated to dryness to obtain oligomer C;

[0064] Step 103. Under a nitrogen atmosphere, the oligomer C obtained in step 102 was dispersed in 2-bromoethanol at a molar ratio of 1:1. An aqueous solution of ethylene glycol was then added dropwise thereto. During the reaction, the concentration of 2-bromoethanol was monitored by HPLC in a water bath at 90°C to maintain a molar ratio of ethylene glycol to oligomer C of 1.1:1. After reacting for 2.5 hours, the mixture was cooled to room temperature and a 10% sodium hydroxide solution was added to precipitate the product, thereby obtaining ethanol-terminated oligomer D.

[0065] Step 104. The ethanol-terminated oligomer D, fatty diol, phthalic anhydride, maleic anhydride and auxiliary agents prepared in step 103 are added to a reactor, and the mixture is reacted at 220° C. under a nitrogen atmosphere for 15 hours. During the reaction, samples are taken from the reaction system every 30 minutes to detect the acid value in the system. When the acid value of the reaction system reaches 30 mgKOH / g, the reaction system is cooled to 90° C. and the reaction is terminated to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin semi-finished product. The semi-finished product is then transferred to a dilution kettle for dilution, and then filtered and packaged to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin finished product.

[0066] The molar ratio of the ethanol-terminated oligomer D, the fatty diol, the phthalic anhydride and the maleic anhydride is 1.05:1.25:1.15:1.

[0067] The phosphorus-sulfur composite flame retardant block-modified unsaturated polyester resin prepared in Examples 1-3 was subjected to the following tests:

[0068] Test 1: Samples of the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resins prepared in Examples 1-3 were respectively prepared into test pieces of the same specifications, and their corresponding limiting oxygen indices were measured;

[0069] Test 2: Samples of the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resins prepared in Examples 1-3 were taken, and test pieces of the same specifications were made. The corresponding UL-94 flame retardancy ratings were then measured.

[0070] Test 3: Stability test: The phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resins prepared in Examples 1-3 were allowed to stand and age, and then made into test pieces of the same specifications. The corresponding UL-94 flame retardancy ratings were measured.

[0071] The aging treatment includes placing the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin prepared in Examples 1-3 at 50°C for 24 hours, 72 hours, and 120 hours, and then measuring its corresponding UL-94 flame retardancy. The test results are shown in Table 1 below.

[0072] Table 1 Test results of Examples 1-3

[0073]

[0074] From the test results table 1 above and Figure 1-Figure 2 It can be seen that the phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin prepared in Examples 1-3 has a high sulfur and phosphorus content, excellent flame retardancy, and excellent aging resistance. After long-term storage, it can still maintain excellent flame retardancy. Under high temperature storage conditions, the phosphorus and sulfur elements in the unsaturated polyester resin will not be phased, the flame retardancy will not be reduced, and it has extremely high thermal stability.

[0075] The dichloromethane solution A and the dichloromethane solution B are reacted and purified to obtain an oligomer C, which is then end-capped with ethanol to obtain an ethanol-terminated oligomer D. Finally, the ethanol-terminated oligomer D, aliphatic diol, phthalic anhydride, maleic anhydride and an auxiliary agent are polymerized and purified to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin, in which phosphorus and sulfur elements account for a large proportion and have excellent flame retardant properties. The content of phosphorus and sulfur elements in the resin can be precisely controlled during the synthesis stage, thereby improving the diversity and applicability of the resin product and meeting the usage needs of different customer groups. The resin has the advantages of low industrialization difficulty, low implementation cost and easy promotion and implementation.

[0076] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

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: Step 101. Add dichloromethane solution A dropwise to dichloromethane solution B, and react in a water bath at 50°C-70°C and 500-1200 rpm for 1-3 hours to obtain crude oligomeric product C. Wherein, dichloromethane solution A is a dichloromethane solution of methylphosphoryl dichloride, and dichloromethane solution B is a dichloromethane solution of 4,4'-diaminodiphenyl sulfone and triethylamine; Step 102. The crude oligomer C obtained after filtering the liquid phase in step 101 is washed sequentially with dilute hydrochloric acid, sodium bicarbonate solution, saturated concentrated brine, and deionized water, and then evaporated to dryness to obtain oligomer C; Step 103. Disperse the oligomer C obtained in step 102 in 2-bromoethanol, then add an aqueous solution of ethylene glycol dropwise thereto. React in a water bath at 70°C-90°C for 1-10 hours, cool to room temperature, and add a 10% sodium hydroxide solution to precipitate the product, thereby obtaining an ethanol-terminated oligomer D. Step 104. Add the ethanol-terminated oligomer D prepared in step 103, aliphatic diol, phthalic anhydride, maleic anhydride, and additives to a reactor and react under an inert gas atmosphere at 150° C.-220° C. for 15-20 hours to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin semi-finished product. The semi-finished product is then transferred to a dilution kettle for dilution, and then filtered and packaged to obtain a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin finished product. In step 101, the dichloromethane solution A is a solution prepared by mixing methylphosphoryl dichloride and dichloromethane solution in a mass ratio of 4:5; Dichloromethane solution B is a solution prepared by mixing 4,4'-diaminodiphenyl sulfone, triethylamine, and dichloromethane solution in a mass ratio of 4:3:5; In step 103, the structural formula of the ethanol-terminated oligomer D is as follows: ， The value range of n is 1680-2100.

2. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: In step 102, the structural formula of oligomer C is as follows: ， The value range of n is 1500-2650.

3. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: In step 103, under a nitrogen atmosphere, the oligomer C obtained in step 102 is dispersed in 2-bromoethanol at a molar ratio of 1:1, and an aqueous solution of ethylene glycol is added dropwise thereto. During the reaction, the concentration of 2-bromoethanol is monitored by HPLC.

4. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: In step 103, during the reaction of oligomer C, the concentration of 2-bromoethanol is monitored by HPLC, and the molar ratio of ethylene glycol to oligomer C is maintained at 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: In step 104 , the molar ratio of the ethanol-terminated oligomer D, the aliphatic diol, the phthalic anhydride, and the maleic anhydride is 1.05:1.25:1.15:

1.

6. The method for synthesizing a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 1, characterized in that: In step 104, during the reaction, samples were taken from the reaction system every 30 minutes to detect the acid value in the system. When the acid value of the reaction system reached 30 mgKOH / g, the reaction system was cooled to 90° C. and the reaction was terminated.

7. A phosphorus-sulfur composite flame retardant block-modified unsaturated polyester resin, characterized in that: The invention is prepared by the synthesis method of a phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin as described in any one of claims 1 to 6.

8. The phosphorus-sulfur composite flame-retardant block-modified unsaturated polyester resin according to claim 7, characterized in that: Its structural formula is as follows: ， The value range of m is 1800-3500, and the value range of n is 1800-2000.

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