Preparation method of high-flexibility flame-retardant monomer
By reacting the active flame retardant group with the phenolic hydroxyl group on the cashew phenol, a high-flexible flame retardant monomer was prepared, which solved the problem of cashew phenol color deepening and double bond integrity, achieving both flame retardant and flexibility, halogen-free and environmentally friendly, low toxicity and low smoke.
Patent Information
- Application Number
- CN202411968074.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-05-02
AI Technical Summary
The color of cashew phenol gradually deepens during long-term use, and when the prior art uses flame retardant and toughening applications through chemical modification, there are few researches on direct reactions based on phenolic hydroxyl groups.
By reacting the reactive flame retardant groups directly with the phenolic hydroxyl group on the cashew phenol, a high flexibility flame retardant monomer was prepared, which solved the color deepening problem and retained the integrity of the unsaturated double bond.
The preparation of high-flexible flame retardant monomers is achieved, with both flame retardant and flexibility, halogen-free and environmentally friendly, low toxicity and low smoke, avoiding the problem of color deepening in traditional methods, and retaining the integrity of the cashew phenol double bond.
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Figure CN119912491A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing a high-flexibility flame-retardant monomer. Background Art
[0002] As an agricultural byproduct distilled from natural cashew nut shell oil, cardanol has the advantages of wide source range, low price, green environmental protection, and renewability. Its unique long-chain structure brings excellent toughness, and the rigid benzene ring brings the characteristics of "hardness and flexibility". It has attracted much attention in recent years, and China is also one of the largest demanders and importers of cardanol.
[0003] Cardanol contains unsaturated double bonds and reactive phenolic hydroxyl groups in its structure, which give it good reactivity, providing a basis for its further modification, and it has great potential in multifunctional chemical products. However, the presence of phenolic hydroxyl groups may cause the color of cardanol to gradually deepen during long-term use. There have been reports on the application of cardanol in flame retardancy and toughening through chemical modification, but basically they are carried out by adding flame retardants to cardanol or polymerizing and grafting the double bonds on cardanol, and there are still few related studies on direct reactions based on phenolic hydroxyl groups. This patent prepares highly flexible flame retardant monomers by directly reacting active flame retardant groups with phenolic hydroxyl groups on cardanol. Summary of the invention
[0004] The purpose of the present invention is to provide a highly flexible flame retardant monomer, which directly replaces the phenolic hydroxyl group on cardanol, effectively solves the problem of color deepening of traditional cardanol after long-term use, and can preserve the integrity of the unsaturated double bonds on cardanol. In addition, it has both flame retardancy and flexibility, is halogen-free and environmentally friendly, and has low toxicity and low smoke.
[0005] To achieve the above object, the method for preparing the highly flexible flame retardant monomer of the present invention comprises the following steps: The method for preparing a highly flexible flame retardant monomer is characterized by comprising the following steps: Firstly, a phosphorus-nitrogen integrated functional compound is prepared with glycine, polyformaldehyde and dimethyl phosphite as raw materials; then, the phosphorus-nitrogen integrated functional compound is modified by chlorination with thionyl chloride; and then, the chlorinated phosphorus-nitrogen integrated functional compound is reacted with phenolic hydroxycardanol to prepare a highly flexible flame retardant monomer.
[0006] The method for preparing the highly flexible flame-retardant monomer of the present invention specifically comprises the following steps: (1) Paraformaldehyde, glycine and tetrahydrofuran are mixed and heated to 60-70°C, and then dimethyl phosphite is added dropwise. After the addition is completed, the temperature is kept constant until the reaction is complete. After the reaction is completed, the solvent tetrahydrofuran is removed to obtain a light yellow viscous liquid, which is a phosphorus-nitrogen integrated functional compound. The phosphorus-nitrogen integrated functional compound is code-named HOOC-NP2.
[0007] (2) The phosphorus-nitrogen integrated functional compound is dissolved in a solvent and a catalyst is added, and thionyl chloride is added dropwise at a temperature of 0-15°C; after the addition is completed, the temperature is raised to 70-80°C and the reaction is continued at this temperature until the reaction is complete to obtain a product solution; saturated salt water and sodium hydroxide solution are added to the product solution to wash the product solution, and then the inorganic phase is separated, and anhydrous sodium sulfate is added to the organic phase for drying. After the drying is completed, the solid-liquid separation is performed, and the solvent is removed from the liquid product obtained by the solid-liquid separation to obtain an acyl chloride modified flame retardant functional monomer. The acyl chloride modified flame retardant functional monomer is code-named ClOC-NP2; the mass concentration of the sodium hydroxide solution is 5%. After the washing is completed, the organic phase and the inorganic phase are generally separated by static stratification, and then the inorganic phase is separated and the organic phase is retained.
[0008] (3) Phenolic hydroxy cardanol (CAS: 501-26-8) is mixed with a solvent and triethylamine is added, and the chlorinated flame retardant functional monomer is dissolved in the solvent to prepare a flame retardant functional monomer solution. The flame retardant functional monomer solution is added dropwise at a temperature of -5°C. After the addition is completed, a low-temperature reaction is first carried out at a temperature of -10-0°C, and then the reaction is continued at a temperature of 5-15°C until the reaction is complete. After the reaction is completed, a liquid crude product is filtered to obtain the liquid crude product, and the liquid crude product is washed with acetic acid solution, NaOH solution, and saturated brine in sequence, and then dried with anhydrous sodium sulfate. After the drying is completed, the product solution is obtained by solid-liquid separation, and the solvent in the product solution is removed to obtain a light yellow viscous product. The thick liquid is a highly flexible flame retardant monomer; the mass concentrations of the acetic acid solution and the NaOH solution are 2% and 10% respectively; the washing and drying operations are as follows: add acetic acid solution to the liquid crude product for washing, let it stand and decompose after washing, separate the inorganic phase and retain the organic phase; then add NaOH solution to the organic phase for washing, let it stand and decompose after washing, separate the inorganic phase and retain the organic phase; then add saturated salt water to the organic phase for washing, let it stand and decompose after washing, separate the inorganic phase and retain the organic phase; finally, add anhydrous sodium sulfate to the organic phase for drying, and perform solid-liquid separation after drying.
[0009] The molar ratio of glycine, paraformaldehyde and dimethyl phosphite is 1.0-1.2:2.0-4.0:4.0.
[0010] In the step (1), after removing the solvent tetrahydrofuran, the following treatment is required: first washing with a small amount of water, then drying with anhydrous sodium sulfate, and finally solid-liquid separation. After solid-liquid separation, a light yellow viscous liquid is obtained, which is the phosphorus-nitrogen integrated functional compound. The washing and drying operation is as follows: after washing with water, standing and stratifying, separating the inorganic phase and retaining the organic phase, and then adding anhydrous sodium sulfate to the organic phase for drying.
[0011] In the steps (1), (2) and (3), the speed of dropping is 1-2 seconds per drop; in step (1), the time of keeping warm after the dropping is completed is 7-9 hours; in step (2), the time of keeping warm after the dropping is completed is 1-2 hours; in step (3), the time of low-temperature reaction and keeping warm after the dropping is completed is 7-9 hours.
[0012] In the step (2), the molar ratio of thionyl chloride to the phosphorus-nitrogen integrated functional compound is 1.1-1.2:1.
[0013] In the step (2), the catalyst is N,N-dimethylformamide (DMF), n-dodecyltrimethylammonium chloride, pyridine or triethylamine; the amount of the catalyst is 3-6% of the mass of thionyl chloride.
[0014] In the step (3), the molar ratio of phenolic hydroxy cardanol to the flame retardant functional monomer modified by acyl chloride is 1:1.0-1.2.
[0015] In the step (3), the amount of triethylamine used is 0.5-1.2 times the mass of phenolic hydroxycardanol.
[0016] In the step (2), the solvent is dichloroethane or chloroform; in the step (3), the solvent is dichloroethane or chloroform.
[0017] The amount of tetrahydrofuran used as a solvent in step (1) is limited to completely dissolving the paraformaldehyde and glycine during the reaction. However, in order to ensure smooth flow of the system during stirring and to make the reaction more balanced in the system, the amount of tetrahydrofuran can be increased appropriately. Similarly, the amount of the solvent in steps (2) and (3) is also limited to completely dissolving the raw materials it dissolves. However, in order to ensure smooth flow of the system during stirring and to make the reaction more balanced in the system, the amount of the solvent in steps (2) and (3) can be increased appropriately.
[0018] The reaction process of step (1) is shown in the following formula: .
[0019] The reaction process of step (2) and step (3) is shown in the following formula: .
[0020] The high-flexibility flame-retardant monomer provided by the present invention has three advantages: (1) the flame-retardant property is combined with the "rigidity and flexibility" of cardanol itself. Cardanol has a rigid benzene ring and a flexible long chain, and the flame-retardant functional monomer contains a large number of flexible groups, which can play a flexible role together with cardanol; (2) the phenolic hydroxyl group on the traditional phenolic hydroxyl cardanol is effectively replaced, avoiding the problem of color deepening during long-term use due to the presence of phenolic hydroxyl groups; (3) different from the traditional long-chain modification, the integrity of the double bond on the long chain of cardanol is retained, which is conducive to the later polymerization reaction. In general, the cardanol of the present invention is halogen-free and environmentally friendly, low in toxicity and smoke, and can be used directly or used as a raw material to further participate in the polymerization reaction. In addition, the reaction process is simple, easy to operate, safe, easy to promote and apply, and has good industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 is the infrared spectrum of the product obtained in step (1) of Example 1; Figure 2 This is the nuclear magnetic resonance spectrum of the product obtained in step (1) of Example 1. DETAILED DESCRIPTION
[0022] The feasibility of the technical solution of the present invention is illustrated below by way of examples, but the protection scope of the present invention should not be limited to the following specific examples. Example 1
[0023] (1) In a three-necked flask equipped with a stirring device, a thermometer and a reflux condenser, add 252 g (2.8 mol) of paraformaldehyde, 152 g (2.0 mol) of glycine and 400 mL of tetrahydrofuran, stir the reaction mixture and heat it to 66°C, then slowly drop 440 g (4.0 mol) of dimethyl phosphite over 1 hour, one drop per 1-2 seconds; after the dropwise addition is completed, continue the reaction at about 66°C for 8 hours. After the reaction is completed, remove the solvent by rotary evaporation to obtain a crude product, wash the crude product with 60 mL of water, let it stand for stratification after washing, separate the inorganic phase, add anhydrous sodium sulfate to the organic phase for drying, and filter after drying to obtain 782 g of a light yellow transparent liquid, which is the phosphorus-nitrogen integrated functional compound (HOOC-NP2).
[0024] (2) In a 500 ml three-necked flask equipped with a stirring device, a thermometer and a reflux condenser, 329 g (1.0 mol) of HOOC-NP2 and 150 mL of dichloroethane were added, and 6.0 g of DMF was added as a catalyst. The temperature was maintained at about 10 °C, and 130.9 g (1.1 mol) of thionyl chloride was slowly dripped into the reaction bottle, one drop per 1-2 seconds. After the dripping was completed, the mixture was heated with stirring and slowly raised to 75 °C. The mixture was stirred and kept warm for 1.5 h at 75 °C. After the reaction was completed, a product solution was obtained. Saturated brine and 5% sodium hydroxide solution were added to the product solution for washing. After washing, the solution was allowed to stand for stratification. The inorganic phase was separated and anhydrous sodium sulfate was added to the organic phase for drying. After filtration, a dichloroethane solution of the flame retardant functional monomer modified by acyl chloride was obtained. The solvent dichloroethane was removed by rotary evaporation to obtain the flame retardant functional monomer modified by acyl chloride (ClOC-NP2).
[0025] (3) 30.25 g (0.1 mol) of commercially available phenolic hydroxycardanol was mixed with 100 ml of dichloroethane solvent and added to a reaction flask, and 20.2 g (0.2 mol) of triethylamine was added. At a constant temperature of -5°C, 34.55 g (0.1 mol) of the ClOC-NP2 prepared above was dissolved in 50 ml of dichloroethane and added to the reaction flask at a drop rate of 2 drops / s. After the addition was completed, the reaction was maintained at a low temperature for 8 hours, and then the temperature was raised to 10°C and the reaction was continued for 8 hours until the reaction was fully completed. After the reaction was completed, the crude liquid product was filtered and washed with 2% acetic acid solution, 10% NaOH solution, and saturated brine in turn, and then dried with anhydrous sodium sulfate. Finally, solid-liquid separation was performed, and the solvent was removed by rotary evaporation to obtain a light yellow viscous liquid, which was a highly flexible flame retardant monomer. Example 2
[0026] (1) In a three-necked flask equipped with a stirring device, a thermometer and a reflux condenser, add 252 g (2.8 mol) of paraformaldehyde, 152 g (2.0 mol) of glycine and 400 mL of tetrahydrofuran, stir the reaction mixture and heat it to 66°C, then slowly drop 440 g (4.0 mol) of dimethyl phosphite over 1 hour, one drop per 1-2 seconds; after the dropwise addition is completed, continue the reaction at about 66°C for 8 hours, after the reaction is completed, remove the solvent by rotary evaporation to obtain a crude product, wash the crude product with 60 mL of water, let it stand after washing, separate the inorganic phase, add anhydrous sodium sulfate to the organic phase for drying, and filter after drying to obtain 782 g of a light yellow transparent liquid, which is the phosphorus-nitrogen integrated functional compound (HOOC-NP2); (2) In a 500 ml three-necked flask equipped with a stirring device, a thermometer and a reflux condenser, 329 g (1.0 mol) of HOOC-NP2 and 100 mL of dichloroethane were added, and 7.0 g of DMF was added as a catalyst. The temperature was maintained at about 10 °C, and 142.8 g (1.2 mol) of thionyl chloride was slowly dripped into the reaction bottle, one drop per 1-2 seconds. After the dripping was completed, the mixture was heated with stirring and slowly heated to 75 °C. The mixture was stirred and kept warm for 1.5 h at 75 °C. After the reaction was completed, a product solution was obtained. Saturated brine and 5% sodium hydroxide solution were added to the product solution for washing. After washing, the solution was allowed to stand for stratification. The inorganic phase was separated and anhydrous sodium sulfate was added to the organic phase for drying. After filtration, a dichloroethane solution of the flame retardant functional monomer modified by acyl chloride was obtained. The solvent dichloroethane was removed by rotary evaporation to obtain the flame retardant functional monomer modified by acyl chloride (ClOC-NP2).
[0027] (3) 30.25 g (0.1 mol) of commercially available phenolic hydroxycardanol was mixed with 100 ml of dichloroethane solvent and added to a reaction flask, and 20.2 g (0.2 mol) of triethylamine was added. At a constant temperature of -5°C, 34.55 g (0.1 mol) of the ClOC-NP2 prepared above was dissolved in 50 ml of dichloroethane and added dropwise to the reaction flask at a drop rate of 2 drops / s. After the addition was completed, the reaction was maintained at a low temperature for 6 hours, and then the temperature was raised to 15°C and the reaction was continued for 6 hours. After the reaction was completed, the crude liquid product was filtered and washed with 2% acetic acid solution, 10% NaOH solution and saturated brine in turn, and then dried with anhydrous sodium sulfate. Finally, solid-liquid separation was performed, and the solvent was removed by rotary evaporation to obtain a light yellow viscous liquid, which was a highly flexible flame retardant monomer. Example 3
[0028] Bisphenol A-bis(diphenyl phosphate) (BDP), resorcinol (diphenyl phosphate) (RDP), ammonium polyphosphate type II (APP), the high-flexibility flame-retardant monomer prepared in Example 1 of the present invention, aluminum hydroxide, triazine carbonizing agent (CFA), and epoxy resin are prepared in a mass ratio of 3.5:2.0:2.0:3.0:2.5:2.0:2.0. A total mass of 15.0 g of the above-mentioned material mixture is prepared and added to a blending container, and then 26 g of acrylic emulsion (emulsion solid content is 50%), 15 g of water, 0.4 g of emulsifier and 0.4 g of defoamer are added, and the mixture is stirred and dispersed evenly to obtain a flame-retardant coating adhesive.
[0029] The flame retardant coating glue was scraped onto the back of the fabric (the fabric was white polyester cloth with a gram weight of 200g, i.e., the weight of each square meter of cloth was 200g), and baked (150°C, 180s) to obtain a low-smoke toxicity and high-efficiency flame retardant polyester sofa textile fabric (Sample 1) with a gram weight gain of 98.6g (i.e., the coating mass of each square meter of cloth was 98.6g). Example 4
[0030] Bisphenol A-bis(diphenyl phosphate) (BDP), resorcinol (diphenyl phosphate) (RDP), ammonium polyphosphate II (APP), aluminum hydroxide, triazine carbonizing agent (CFA), and epoxy resin are prepared according to a mass ratio of 5.5:2.0:3.0:2.5:2.0:2.0, and a total mass of 15.0g of the above-mentioned material mixture is added to a blending container, and then 26g of acrylic emulsion (emulsion solid content is 50%), 15g of water, 0.4g of emulsifier and 0.4g of defoamer are added, and stirred and dispersed uniformly to obtain a flame retardant coating adhesive. The formula does not contain the high-flexibility flame retardant monomer provided by the present invention.
[0031] The flame retardant coating glue was scraped onto the back of the fabric (the fabric was white polyester cloth with a gram weight of 200g, i.e., the weight of each square meter of cloth was 200g), and baked (150°C, 180s) to obtain a low-smoke and high-efficiency flame retardant polyester sofa textile fabric (Sample 2) with a gram weight gain of 100.8g (i.e., the coating mass of each square meter of cloth was 100.8g). Example 5
[0032] Bisphenol A-bis(diphenyl phosphate) (BDP), resorcinol (diphenyl phosphate) (RDP), ammonium polyphosphate type II (APP), the high-flexibility flame-retardant monomer prepared in Example 2 of the present invention, aluminum hydroxide, triazine carbonizing agent (CFA), and epoxy resin are prepared in a mass ratio of 3.5:2.0:2.0:3.0:2.5:2.0:2.0. A total mass of 15.0 g of the above-mentioned material mixture is added to a blending container, and then 26 g of acrylic emulsion (emulsion solid content of 50%), 15 g of water, 0.4 g of emulsifier and 0.4 g of defoamer are added, and the mixture is stirred and dispersed evenly to obtain a flame-retardant coating adhesive.
[0033] The flame retardant coating glue was scraped onto the back of the fabric (the fabric was white polyester cloth with a gram weight of 200g, i.e., the weight of each square meter of cloth was 200g), and baked (150°C, 180s) to obtain a low-smoke toxicity and high-efficiency flame retardant polyester sofa textile fabric (Sample 3) with a gram weight gain of 98.6g (i.e., the coating mass of each square meter of cloth was 98.6g).
[0034] From the hand feeling, samples 1 and 3 are obviously soft due to the presence of flexible segments such as cardanol, while sample 2 is harder. In practical applications, the softer the fabric, the more it meets market demand.
[0035] With reference to the BS5852 flame retardant test standard, Samples 1, 2 and 3 were covered with the specified polyurethane sponge respectively, and placed under the specified burner to ignite, with the butane flame height of 35mm. After the flame stabilized for 30 seconds, the flame continued to burn the sample for 20 seconds to test the flame retardant performance of the sample. Samples 1 and 3 burned out immediately after leaving the flame after burning for 20 seconds, and passed the BS5852 standard; while Sample 2 burned through within 20 seconds, and the flame continued to burn without self-extinguishing, and failed to pass the standard. The test results are shown in the table below.
[0036]
[0037] The above is only a preferred embodiment of the present invention, and does not limit the technical solution of the present invention in any form. Any equivalent replacement or partial improvement made under the technical essence of the present invention will be regarded as within the protection scope of the present invention.
Claims
1. A method for preparing a highly flexible flame retardant monomer, characterized in that The following steps are involved: Firstly, a phosphorus-nitrogen integrated functional compound is prepared with glycine, polyformaldehyde and dimethyl phosphite as raw materials; then, the phosphorus-nitrogen integrated functional compound is modified by chlorination with thionyl chloride; and then, the chlorinated phosphorus-nitrogen integrated functional compound is reacted with phenolic hydroxycardanol to prepare a highly flexible flame retardant monomer.
2. The method for preparing a highly flexible flame retardant monomer according to claim 1, characterized in that The following steps are involved: (1) paraformaldehyde, glycine and tetrahydrofuran are mixed and heated to 60-70°C, and then dimethyl phosphite is added dropwise. After the addition is completed, the temperature is kept constant until the reaction is complete. After the reaction is completed, the solvent tetrahydrofuran is removed to obtain a light yellow viscous liquid, which is a phosphorus-nitrogen integrated functional compound; (2) dissolving the phosphorus-nitrogen integrated functional compound in a solvent and adding a catalyst, and then dripping thionyl chloride at a temperature of 0-15°C; after the dripping is completed, the temperature is raised to 70-80°C and the reaction is continued at this temperature until the reaction is complete to obtain a product solution; saturated salt water and sodium hydroxide solution are added to the product solution to wash the product solution, and then the inorganic phase is separated, and anhydrous sodium sulfate is added to the organic phase for drying. After the drying is completed, solid-liquid separation is performed, and the solvent is removed from the liquid product obtained by solid-liquid separation to obtain an acyl chloride-modified flame retardant functional monomer; (3) Phenolic hydroxy cardanol is mixed with a solvent and triethylamine is added, and the acyl chloride-modified flame retardant functional monomer is dissolved in the solvent to prepare a flame retardant functional monomer solution. The flame retardant functional monomer solution is added dropwise at a temperature of -10-0°C. After the addition is completed, a low-temperature reaction is first carried out at a temperature of -10-0°C, and then the reaction is continued at a temperature of 5-15°C until the reaction is complete. After the reaction is completed, a liquid crude product is filtered, and the liquid crude product is washed with acetic acid solution, NaOH solution, and saturated brine in turn, and then dried with anhydrous sodium sulfate. After drying, a solid-liquid separation is performed to obtain a product solution. After removing the solvent in the product solution, a light yellow viscous liquid is obtained, which is a high-flexibility flame retardant monomer.
3. The method for preparing a highly flexible flame-retardant monomer according to claim 2, characterized in that: The molar ratio of glycine, paraformaldehyde and dimethyl phosphite is 1.0-1.2:2.0-4.0:4.
0.
4. The method for preparing a highly flexible flame-retardant monomer according to claim 2, characterized in that: In the step (1), after removing the solvent tetrahydrofuran, the following treatment is required: first washing with a small amount of water, then drying with anhydrous sodium sulfate, and finally solid-liquid separation. After solid-liquid separation, a light yellow viscous liquid is obtained, which is the phosphorus-nitrogen integrated functional compound.
5. The method for preparing a highly flexible flame-retardant monomer according to claim 2, characterized in that: In the steps (1), (2) and (3), the speed of dropping is 1-2 seconds per drop; in step (1), the time of continuing the heat preservation reaction after the drop addition is completed is 7-9 hours; in step (2), the time of continuing the heat preservation reaction after the drop addition is completed is 1-2 hours; in step (3), the time of low temperature reaction and heat preservation reaction after the drop addition is completed is 7-9 hours.
6. The method for preparing a highly flexible flame-retardant monomer according to claim 2, characterized in that: In the step (2), the molar ratio of thionyl chloride to the phosphorus-nitrogen integrated functional compound is 1.1-1.2:
1.
7. The method for preparing a highly flexible flame-retardant monomer according to claim 2, characterized in that: In the step (2), the catalyst is N,N-dimethylformamide, n-dodecyltrimethylammonium chloride, pyridine or triethylamine; the amount of the catalyst is 3-6% of the mass of thionyl chloride.
8. The method for preparing a highly flexible flame-retardant monomer according to claim 2, characterized in that: In the step (3), the molar ratio of phenolic hydroxy cardanol to the flame retardant functional monomer modified by acyl chloride is 1:1.0-1.
2.
9. The method for preparing a highly flexible flame-retardant monomer according to claim 2, characterized in that: In the step (3), the amount of triethylamine used is 0.5-1.2 times the mass of phenolic hydroxycardanol.
10. The method for preparing a highly flexible flame-retardant monomer according to claim 2, characterized in that: In the step (2), the solvent is dichloroethane or chloroform; in the step (3), the solvent is dichloroethane or chloroform.