A flame retardant plasticizer and its preparation method and application

Abstract

The present invention relates to a plasticizer, and discloses a flame retardant plasticizer and a preparation method and application thereof, using 1,4-dibromo-2,3-butanediol, diphenyl chlorophosphate and a paraben compound as reaction raw materials, through phosphating reaction and etherification reaction, a novel flame retardant plasticizer is prepared. The flame retardant plasticizer not only contains an alkyl long chain, but also contains a phosphate polar functional group, which can be well embedded in the molecular chain of polyvinyl chloride, increases the distance between the molecular chains of polyvinyl chloride, thereby reducing the interaction between the molecular chains of polyvinyl chloride, and plays a good plasticizing effect, and the flame retardant plasticizer contains multiple rigid aromatic ring structures, which can improve the strength and modulus of polyvinyl chloride, and show higher tensile strength and hardness, and the flame retardant plasticizer contains a bisphosphate phenyl ester flame retardant structure, so that polyvinyl chloride shows a higher limiting oxygen index and good flame retardant properties.

Description

Technical Field

[0001] The invention relates to a plasticizer, in particular to a flame retardant plasticizer and a preparation method and application thereof. Background Art

[0002] Plasticizer is a functional additive that can improve the flexibility and processing properties of materials. It is widely used in polymer materials such as polyvinyl chloride and rubber. Traditional plasticizers mainly include dioctyl phthalate, triphenyl phosphate, triethyl citrate, etc. Among them, dioctyl phthalate has a good plasticizing effect and is a common plasticizer for polyvinyl chloride. However, dioctyl phthalate has poor migration resistance and is easy to migrate to the surface of the matrix in the polyvinyl chloride matrix, which is very harmful to human health. And when the amount of dioctyl phthalate added is large, the strength of polyvinyl chloride will be reduced and the flame retardancy will deteriorate. In recent years, the development of high-performance plasticizers has become a research trend. CN113372550B discloses a vanillic acid-based flame retardant plasticizer and its preparation and application in CN114671908B. Alkyl chains and phosphorus elements are introduced into the vanillic acid structure. The prepared vanillic acid-based flame retardant plasticizer can significantly improve the flame retardant properties of polyvinyl chloride materials, and the plasticity and flexibility are not reduced. However, the vanillic acid-based flame retardant plasticizer in this patent does not show good migration resistance. Summary of the invention

[0003] The invention solves the problem that the existing plasticizer has poor plasticizing effect on polyvinyl chloride.

[0004] Technical solution: A flame retardant plasticizer, the chemical structure of which is formula (I):

[0005] In formula (I), n is any integer between 7 and 10.

[0006] Further, the preparation method of the flame retardant plasticizer is as follows:

[0007] (1) Adding a solvent, 1,4-dibromo-2,3-butanediol, diphenyl chlorophosphate, and pyridine in a ratio of 1 mol:(2.3-3) mol:(2.3-3) mol to a flask at 0-5°C, then heating to a reaction temperature, stirring the reaction, rotary evaporation, and column chromatography separation to obtain a plasticizer precursor.

[0008] (2) Add N,N-dimethylformamide, a plasticizer precursor in a ratio of 1 mol:(2-2.3) mol:(6.5-8) mol, a p-hydroxybenzoate compound, and potassium carbonate to a flask equipped with a condenser reflux tube, introduce nitrogen, heat to the reaction temperature, stir to react, add water and dichloromethane after cooling, extract and separate, dry the organic phase with anhydrous magnesium sulfate, filter and rotary evaporate the filtrate, separate by column chromatography, and obtain a flame retardant plasticizer. The reaction formula is:

[0009]

[0010] Furthermore, the solvent in (1) is tetrahydrofuran, toluene or ethyl acetate.

[0011] Furthermore, in (1), the reaction temperature is 35-50° C., and the reaction time is 6-10 h.

[0012] Further, the structural formula of the paraben compound is n is any integer value between 7 and 10.

[0013] Furthermore, in (2), the reaction temperature is 130-145° C., and the reaction time is 6-12 h.

[0014] Furthermore, the flame retardant plasticizer is used in polyvinyl chloride.

[0015] Technical effect: The present invention uses 1,4-dibromo-2,3-butanediol, diphenyl chlorophosphate and paraben compounds as reaction raw materials, and prepares a new flame retardant plasticizer through phosphating reaction and etherifying reaction. The flame retardant plasticizer not only contains alkyl long chains, but also contains phosphate polar functional groups, which can be well embedded in the molecular chain of polyvinyl chloride, increase the distance between polyvinyl chloride molecular chains, thereby reducing the interaction between polyvinyl chloride molecular chains, and play a good plasticizing effect, and the elongation at break reaches 442.0-483.7%. In addition, the flame retardant plasticizer contains multiple rigid aromatic ring structures, which produce large steric hindrance in the polyvinyl chloride molecular chain, can limit the movement of the polymer molecular chain, thereby improving the strength and modulus of polyvinyl chloride, and showing higher tensile strength and hardness, with a tensile strength of 21.3-23.4MPa and a Shore hardness of 73.9-76.6. Compared with traditional dioctyl phthalate, the flame retardant plasticizer of the invention has a larger molecular weight, contains long alkyl chains and phosphate polar functional groups, has a stronger interface interaction with polyvinyl chloride, is not easy to migrate in the polyvinyl chloride matrix, and exhibits better migration resistance.

[0016] The flame-retardant plasticizer of the present invention contains a flame-retardant structure of bisphosphate phenyl ester. When burned, it undergoes high-temperature thermal decomposition to generate free radicals such as phosphoric acid and phosphorus oxygen. The phosphoric acid can promote the dehydration of polyvinyl chloride into carbon, and can inhibit the heat and material exchange process between the gas phase and the condensed phase, thereby isolating heat transfer and preventing oxygen from contacting the polyvinyl chloride body. The flame-retardant plasticizer has a good flame-retardant effect. Meanwhile, the free radicals such as phosphorus oxygen can capture free radicals of a combustion chain reaction, inhibit the combustion reaction process, and enable the polyvinyl chloride to exhibit a higher limiting oxygen index and good flame-retardant performance. DETAILED DESCRIPTION

[0017] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0018] Example 1

[0019] (1) At 0°C, add 200 mL of tetrahydrofuran solvent, 30 mmol 1,4-dibromo-2,3-butanediol (CAS No. 14396-65-7), 75 mmol diphenyl chlorophosphate (CAS No. 2524-64-3), and 90 mmol pyridine to a flask, then heat to 40°C, stir and react for 6 hours, rotary evaporate, and separate by column chromatography. The eluent is a mixed solution of petroleum ether and ethyl acetate, and the elution is performed in a gradient manner to obtain a plasticizer precursor. The structural formula is:

[0020] (2) Add 150 mL of N,N-dimethylformamide, 20 mmol of plasticizer precursor, and 46 mmol of heptylparaben (CAS No. 1085-12-7, structural formula: ), 130 mmol potassium carbonate, nitrogen was introduced, the temperature was raised to 140°C, stirred for 12 hours, water and dichloromethane were added after cooling, and the organic phase was dried over anhydrous magnesium sulfate, the filtrate was rotary evaporated after suction filtration, and column chromatography was used for separation. The eluent was a mixed solution of petroleum ether and ethyl acetate, and the gradient elution was performed to obtain a flame retardant plasticizer. The structural formula is:

[0021]

[0022] (3) 100 g of polyvinyl chloride resin, 30 g of flame retardant plasticizer, 2 g of zinc stearate, and 3.2 g of calcium zinc stabilizer were added to a twin-screw extruder, and the six-stage temperatures were 150°C, 155°C, 160°C, 170°C, 170°C, and 165°C, and the screw speed was 30 r / min. After extrusion, granulation was performed; and injection molding was performed in an injection molding machine, and the three-stage temperatures of the injection molding machine were 160°C, 165°C, and 170°C to obtain a polyvinyl chloride material.

[0023] Example 2

[0024] (1) At 5°C, 300 mL of ethyl acetate solvent, 30 mmol 1,4-dibromo-2,3-butanediol, 90 mmol diphenyl chlorophosphate, and 90 mmol pyridine were added to a flask, and then the temperature was raised to 35°C, stirred for reaction for 10 h, rotary evaporated, and separated by column chromatography. The eluent was a mixed solution of petroleum ether and ethyl acetate, and the elution was performed in a gradient manner to obtain a plasticizer precursor.

[0025] (2) Add 150 mL of N,N-dimethylformamide, 20 mmol of plasticizer precursor, and 40 mmol of n-octyl p-hydroxybenzoate (CAS No. 1219-38-1, structural formula: ), 130 mmol potassium carbonate, nitrogen was introduced, the temperature was raised to 130°C, stirred for 12 hours, water and dichloromethane were added after cooling, and the organic phase was dried over anhydrous magnesium sulfate, the filtrate was rotary evaporated after suction filtration, and column chromatography was used for separation. The eluent was a mixed solution of petroleum ether and ethyl acetate, and the gradient elution was performed to obtain a flame retardant plasticizer. The structural formula is:

[0026]

[0027] (3) 100 g of polyvinyl chloride resin, 30 g of flame retardant plasticizer, 2 g of zinc stearate, and 3.2 g of calcium zinc stabilizer were added to a twin-screw extruder, and the six-stage temperatures were 150°C, 155°C, 160°C, 170°C, 170°C, and 165°C, and the screw speed was 30 r / min. After extrusion, granulation was performed; and injection molding was performed in an injection molding machine, and the three-stage temperatures of the injection molding machine were 160°C, 165°C, and 170°C to obtain a polyvinyl chloride material.

[0028] Example 3

[0029] (1) At 0°C, 200 mL of ethyl acetate solvent, 30 mmol 1,4-dibromo-2,3-butanediol, 69 mmol diphenyl chlorophosphate, and 69 mmol pyridine were added to a flask, and then the temperature was raised to 35°C, stirred for reaction for 8 h, rotary evaporated, and separated by column chromatography. The eluent was a mixed solution of petroleum ether and ethyl acetate, and the elution was performed in a gradient manner to obtain a plasticizer precursor.

[0030] (2) Add 200 mL of N,N-dimethylformamide, 20 mmol of plasticizer precursor, and 44 mmol of nonyl p-hydroxybenzoate (CAS No. 38713-56-3, structural formula: ), 140 mmol potassium carbonate, nitrogen was introduced, the temperature was raised to 135°C, stirred for 12 hours, water and dichloromethane were added after cooling, and the organic phase was dried with anhydrous magnesium sulfate, the filtrate was rotary evaporated after suction filtration, and column chromatography was used for separation. The eluent was a mixed solution of petroleum ether and ethyl acetate, and the gradient elution was performed to obtain a flame retardant plasticizer. The structural formula is:

[0031]

[0032] (3) 100 g of polyvinyl chloride resin, 30 g of flame retardant plasticizer, 2 g of zinc stearate, and 3.2 g of calcium zinc stabilizer were added to a twin-screw extruder, and the six-stage temperatures were 150°C, 155°C, 160°C, 170°C, 170°C, and 165°C, and the screw speed was 30 r / min. After extrusion, granulation was performed; and injection molding was performed in an injection molding machine, and the three-stage temperatures of the injection molding machine were 160°C, 165°C, and 170°C to obtain a polyvinyl chloride material.

[0033] Example 4

[0034] (1) At 0°C, 250 mL of toluene solvent, 30 mmol 1,4-dibromo-2,3-butanediol, 69 mmol diphenyl chlorophosphate, and 82 mmol pyridine were added to a flask, and then the temperature was raised to 50°C, stirred for reaction for 6 h, rotary evaporated, and separated by column chromatography. The eluent was a mixed solution of petroleum ether and ethyl acetate, and the elution was performed in a gradient manner to obtain a plasticizer precursor.

[0035] (2) Add 200 mL of N,N-dimethylformamide, 20 mmol of plasticizer precursor, and 44 mmol of decyl p-hydroxybenzoate (CAS No. 69679-30-7, structural formula: ), 160 mmol potassium carbonate, nitrogen was introduced, the temperature was raised to 145°C, stirred for 6 hours, water and dichloromethane were added after cooling, and the organic phase was dried over anhydrous magnesium sulfate, the filtrate was rotary evaporated after suction filtration, and column chromatography was used for separation. The eluent was a mixed solution of petroleum ether and ethyl acetate, and the gradient elution was performed to obtain a flame retardant plasticizer. The structural formula is:

[0036]

[0037] (3) 100 g of polyvinyl chloride resin, 30 g of flame retardant plasticizer, 2 g of zinc stearate, and 3.2 g of calcium zinc stabilizer were added to a twin-screw extruder, and the six-stage temperatures were 150°C, 155°C, 160°C, 170°C, 170°C, and 165°C, and the screw speed was 30 r / min. After extrusion, granulation was performed; and injection molding was performed in an injection molding machine, and the three-stage temperatures of the injection molding machine were 160°C, 165°C, and 170°C to obtain a polyvinyl chloride material.

[0038] Comparative Example 1

[0039] 100g polyvinyl chloride resin, 2g zinc stearate, 30g dioctyl phthalate, and 3.2g calcium zinc stabilizer were added to a twin-screw extruder, and the six-stage temperatures were 150°C, 155°C, 160°C, 170°C, 170°C, and 165°C, and the screw speed was 30r / min. After extrusion, granulation was performed; injection molding was performed in an injection molding machine, and the three-stage temperatures of the injection molding machine were 160°C, 165°C, and 170°C to obtain a polyvinyl chloride material.

[0040] Take two filter papers of the same size, weigh them together, record as m0; then press the polyvinyl chloride material into a film, and put it between the two filter papers, then put it in an oven, heat treat it at 60℃ for 48h, and then weigh the two filter papers, record as m1. Calculate the weight gain rate. Weight gain rate = (m1-m0) / m0×100%. Test each group of samples 5 times and take the average value. The greater the weight gain rate, the more plasticizer migrates to the PVC surface, and the worse the migration resistance.

[0041] Table 1 Plasticizer migration test

[0042] Weight gain rate (%) Example 1 0.139 Example 2 0.127 Example 3 0.106 Example 4 0.112 Comparative Example 1 0.492

[0043] Table 2 Performance test of polyvinyl chloride materials

[0044]

[0045]

[0046] As shown in Table 1 and Table 2, Comparative Example 1 uses dioctyl phthalate as a plasticizer, and the elongation at break of polyvinyl chloride reaches 472.3%, and the plasticizing effect is very good, but the limiting oxygen index is only 23.9%, and the flame retardancy is not good. The polyvinyl chloride of Examples 1-4 is added with a novel flame retardant plasticizer, and the plasticizer structure not only contains an alkyl long chain, but also contains a phosphate polar functional group, which can be well embedded in the molecular chain of polyvinyl chloride, increasing the distance between the molecular chains of polyvinyl chloride, thereby reducing the interaction between the molecular chains of polyvinyl chloride, and playing a good plasticizing effect, and the elongation at break reaches 442.0-483.7%. And the flame retardant plasticizer contains multiple rigid aromatic ring structures, which produce a large steric hindrance in the molecular chain of polyvinyl chloride, and can limit the movement of the polymer molecular chain, thereby improving the strength and modulus of polyvinyl chloride, showing higher tensile strength and hardness, with a tensile strength of 21.3-23.4MPa and a Shore hardness of 73.9-76.6, which are significantly higher than Comparative Example 1. Compared with traditional dioctyl phthalate, flame retardant plasticizers have a larger molecular weight and contain long alkyl chains and phosphate polar functional groups. They have stronger interfacial interaction with polyvinyl chloride, are not easy to migrate in the polyvinyl chloride matrix, and exhibit better migration resistance.

[0047] The flame-retardant plasticizer of the present invention contains a flame-retardant structure of bisphosphate phenyl ester. When burned, it undergoes high-temperature thermal decomposition to generate free radicals such as phosphoric acid and phosphorus oxygen. The phosphoric acid can promote the dehydration of polyvinyl chloride into carbon, and can inhibit the heat and material exchange process between the gas phase and the condensed phase, thereby isolating heat transfer and preventing oxygen from contacting the polyvinyl chloride body. The flame-retardant plasticizer has a good flame-retardant effect. Meanwhile, the free radicals such as phosphorus oxygen can capture free radicals of a combustion chain reaction, inhibit the combustion reaction process, and enable the polyvinyl chloride to exhibit a higher limiting oxygen index and good flame-retardant performance.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A flame retardant plasticizer, characterized in that: The chemical structural formula of the flame retardant plasticizer is formula (I): In formula (I), n is any integer between 7 and 10.

2. The method for preparing a flame retardant plasticizer according to claim 1, characterized in that: The preparation method is as follows: (1) adding a solvent, 1,4-dibromo-2,3-butanediol, diphenyl chlorophosphate, and pyridine to a flask at 0-5° C., then heating to a reaction temperature, stirring for reaction, rotary evaporation, and column chromatography separation to obtain a plasticizer precursor; (2) Add N,N-dimethylformamide, plasticizer precursor, p-hydroxybenzoate compound and potassium carbonate to a flask equipped with a condenser reflux tube, introduce nitrogen, heat to the reaction temperature, stir to react, add water and dichloromethane after cooling, extract and separate, dry the organic phase with anhydrous magnesium sulfate, filter and rotary evaporate the filtrate, separate by column chromatography, and obtain a flame retardant plasticizer.

3. The method for preparing a flame retardant plasticizer according to claim 2, characterized in that: The solvent in (1) is tetrahydrofuran, toluene or ethyl acetate.

4. The method for preparing a flame retardant plasticizer according to claim 2, characterized in that: The ratio of 1,4-dibromo-2,3-butanediol, diphenyl chlorophosphate and pyridine in (1) is 1 mol:(2.3-3) mol:(2.3-3) mol.

5. The method for preparing a flame retardant plasticizer according to claim 2, characterized in that: In the step (1), the reaction temperature is 35-50°C and the reaction time is 6-10h.

6. The method for preparing a flame retardant plasticizer according to claim 2, characterized in that: The ratio of the plasticizer precursor, the p-hydroxybenzoate compound and the potassium carbonate in (2) is 1 mol: (2-2.3) mol: (6.5-8) mol.

7. The method for preparing a flame retardant plasticizer according to claim 6, characterized in that: The structural formula of the p-hydroxybenzoate compound is n is any integer value between 7 and 10.

8. The method for preparing a flame retardant plasticizer according to claim 2, characterized in that: In the step (2), the reaction temperature is 130-145° C., and the reaction time is 6-12 h.

9. Use of the flame retardant plasticizer obtained by the preparation method according to any one of claims 1 to 8 in polyvinyl chloride.

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