Preparation method of intrinsic flame-retardant high-elasticity styrene-acrylic emulsion

Abstract

The invention discloses a preparation method of an intrinsic flame-retardant high-elasticity styrene-acrylic emulsion. The preparation method comprises the following steps: firstly, preparing a phosphorus-nitrogen integrated functional compound by taking glycine, paraformaldehyde and dimethyl phosphite as raw materials; then carrying out acylating chlorination modification on the phosphorus-nitrogen integrated functional compound by using thionyl chloride; reacting the phosphorus-nitrogen integrated functional compound modified by acylating chlorination with phenolic hydroxyl cardanol to prepare a high-flexibility flame-retardant monomer; and finally, reacting a high-flexibility flame-retardant monomer, styrene, butyl acrylate and acrylic acid in the cationic etherified starch aqueous solution to prepare the flame-retardant high-elasticity styrene-acrylic emulsion. The emulsion has multiple advantages of flame retardance, high elasticity, no soap, water resistance and the like, is green and environment-friendly, is low in cost and has wide application value.

Description

Technical Field

[0001] The invention relates to a method for preparing an intrinsically flame-retardant high-elastic styrene-acrylic emulsion. Background Art

[0002] Styrene acrylic emulsion is an emulsion prepared by polymerization under certain conditions with styrene and acrylate monomers as the main body, in the presence of a small amount of other compounds and additives. It is widely used in coating-related fields due to its low cost. Due to the large amount of emulsifier added in the traditional emulsion polymerization method, the quality of the emulsion is reduced, and problems such as yellowing and odor appear. One of the solutions is to reduce the amount of emulsifier used and adopt a soap-free emulsion polymerization method. Starch, as a green, environmentally friendly and renewable resource with a wide source and favorable price, is a better solution to replace traditional emulsifiers. By grafting cationic starch onto styrene acrylic emulsion, an emulsion product with good water resistance and film-forming properties can be prepared.

[0003] On the other hand, with the development of society and people's emphasis on safety, there is an increasing demand for styrene acrylic emulsions in the fields of fabric flame retardancy, and higher elasticity and better flame retardancy are the hot spots pursued by the industry. As an agricultural by-product distilled from natural cashew nut shell oil, cardanol has the advantages of a wide range of sources, 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", which has attracted much attention in recent years.

[0004] By modifying cardanol with phenolic hydroxyl groups to prepare flame-retardant high-elastic cardanol, and then introducing it into a styrene-acrylic emulsion system, a high-elastic intrinsic flame-retardant styrene-acrylic emulsion can be prepared. The present invention first etherifies starch to make it into a cationic starch, and then uses it for flame-retardant modified cardanol, styrene, acrylate, and acrylic acid graft emulsion polymerization to prepare a styrene-acrylic emulsion with high flame retardancy, high water resistance, and high elasticity. The preparation of the intrinsic flame-retardant high-elastic styrene-acrylic emulsion can provide a new idea for the market demand. Summary of the invention

[0005] The object of the present invention is to provide an intrinsically flame-retardant high-elastic styrene-acrylic emulsion.

[0006] To achieve the above-mentioned purpose, the preparation method of the intrinsically flame-retardant high-elastic styrene-acrylic emulsion described in the present invention comprises the following steps: firstly, glycine, paraformaldehyde and dimethyl phosphite are used as raw materials to prepare a phosphorus-nitrogen integrated functional compound; then, the phosphorus-nitrogen integrated functional compound is chlorinated with thionyl chloride; then, the chlorinated phosphorus-nitrogen integrated functional compound is reacted with phenolic hydroxy cardanol to prepare a high-flexibility flame-retardant monomer; finally, the high-flexibility flame-retardant monomer, styrene, butyl acrylate and acrylic acid are reacted in a cationic etherified starch aqueous solution to prepare an intrinsically flame-retardant high-elastic styrene-acrylic emulsion.

[0007] The method for preparing the intrinsically flame-retardant high-elastic styrene-acrylic emulsion of the present invention comprises the following specific 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.

[0008] (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.

[0009] (3) Phenolic hydroxy cardanol (CAS: 501-26-8) was mixed with a solvent and triethylamine was added. The chlorinated flame retardant functional monomer was dissolved in the solvent to prepare a flame retardant functional monomer solution. The flame retardant functional monomer solution was added dropwise at a temperature of -5°C. After the addition was completed, a low-temperature reaction was first carried out at a temperature of -10-0°C, and then the reaction was continued at a temperature of 5-15°C until the reaction was complete. After the reaction was completed, a liquid crude product was filtered to obtain a liquid crude product. The liquid crude product was washed with acetic acid solution, NaOH solution, and saturated brine in sequence, and then dried with anhydrous sodium sulfate. After drying, a solid-liquid separation was performed to obtain a product solution. After removing the solvent from the product solution, a light yellow viscous liquid was obtained, which was a highly flexible flame retardant monomer. The mass concentrations of the acetic acid solution and the NaOH solution were 2% and 10%, respectively. The washing and drying operations were as follows: the acetic acid solution was added to the liquid crude product for washing. After the washing was completed, the product was allowed to stand for stratification, and the inorganic phase was separated and the organic phase was retained. Then, NaOH was added to the organic phase. The solution is washed, and after washing, the mixture is allowed to stand and separate, the inorganic phase is separated and the organic phase is retained; saturated salt water is added to the organic phase for washing, and after washing, the mixture is allowed to stand and separate, the inorganic phase is separated and the organic phase is retained; finally, anhydrous sodium sulfate is added to the organic phase for drying, and after drying, solid-liquid separation is performed; (4) Mix starch and water, heat the water bath to 40-60°C, add ammonia water to adjust the pH value to 8.5-10, add etherifying agent, keep warm and stir for 1-2 hours, then add hydrogen peroxide, keep warm for 30-60 minutes, then heat to 70-90°C and continue to react for 0.3-1 hour. After the reaction is completed, a transparent cationic etherified starch aqueous solution is obtained; (5) Heat the cationic etherified starch aqueous solution to 60-85°C in a water bath, add hydrogen peroxide and potassium persulfate aqueous solution dropwise, keep adding, add high-flexibility flame retardant monomer and styrene, carry out a first polymerization reaction for 0.5-2 h, then add butyl acrylate and acrylic acid, carry out a repolymerization reaction for 0.5-2 h, and at the end of the repolymerization reaction, add hydrogen peroxide and potassium persulfate aqueous solution dropwise, continue to keep warm for 2-4 h after the addition is completed, and adjust the pH of the reaction solution to 6-8 with ammonia water to obtain a slightly yellowish milky white styrene-acrylic emulsion, which is an intrinsically flame-retardant high-elasticity styrene-acrylic emulsion.

[0010] The molar ratio of glycine, paraformaldehyde and dimethyl phosphite is 1.0-1.2:2.0-4.0:4.0.

[0011] 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.

[0012] 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.

[0013] In the step (2), the molar ratio of thionyl chloride to the phosphorus-nitrogen integrated functional compound is 1.1-1.2:1.

[0014] 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.

[0015] 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; and the amount of triethylamine used is 0.5-1.2 times the mass of phenolic hydroxy cardanol.

[0016] In the step (4), the mass ratio of starch to water is 1:1-1:4, the etherifying agent is 2,3-epoxypropyltrimethylammonium chloride or ‌3-chloro-2-hydroxypropyltrimethylammonium chloride, the amount of the etherifying agent is 5%-20% of the mass of the starch, the concentration of the hydrogen peroxide is 2-3%, and the amount of the hydrogen peroxide is 0.5-2 times the mass of the starch.

[0017] In the step (5), the amount of the high-flexibility flame-retardant monomer is 10%-30% of the mass of the cationic etherified starch aqueous solution, the amount of styrene is 0.5-5 times the mass of the high-flexibility flame-retardant monomer, the amount of butyl acrylate is 0.3-2 times the mass of the high-flexibility flame-retardant monomer, and the amount of acrylic acid is 0.05-0.5 times the mass of the high-flexibility flame-retardant monomer; the amount of potassium persulfate is 2%-10% of the total mass of the high-flexibility flame-retardant monomer, styrene, butyl acrylate, and acrylic acid; the concentration of the hydrogen peroxide is 2-3%, and the amount is 0.3-1 times the total mass of the high-flexibility flame-retardant monomer, styrene, butyl acrylate, and acrylic acid.

[0018] In the step (2), the solvent is dichloroethane or chloroform; in the step (3), the solvent is dichloroethane or chloroform.

[0019] 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.

[0020] The reaction process of step (1) is shown in the following formula: .

[0021] The reaction process of step (2) and step (3) is shown in the following formula: .

[0022] The reaction process of step (5) is shown below: . The advantages of the present invention are that the prepared product has multiple advantages such as flame retardancy, high elasticity, soap-free, and water-resistant. On the one hand, the flame retardant function of the copolymer comes from the rich flame retardant groups in the high phosphorus content flame retardant with reactive functional groups, which is rich in phosphorus content, halogen-free and environmentally friendly, and has a high carbonization rate; on the other hand, the high elastic toughening effect comes from the flexible groups in the functional monomer HOOC-NP2 and the large number of flexible segments in cardanol; on the other hand, the soap-free synthesis avoids the yellowing and odor problems caused by the high content of emulsifier; on the other hand, due to the cationization of starch, its water resistance is improved; on the other hand, the intrinsic flame retardant high elastic emulsion of the present invention can freely adjust the proportion of flame retardant groups, cardanol, styrene, acrylic acid, etc., and a reasonable proportion can optimize the performance of the copolymer. This product is green and environmentally friendly, low in cost, and has a wide range of application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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

[0024] 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

[0025] (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).

[0026] (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).

[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 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.

[0028] (4) Add 40 g of starch and 120 g of water into a four-necked reaction bottle with heating and mechanical stirring, heat it to 55 °C in a water bath, add an appropriate amount of ammonia water to adjust the pH value to 9, then add 5 g of etherifying agent 2,3-epoxypropyltrimethylammonium chloride, keep warm and stir for 1.5 h, then add 30 g of 3% hydrogen peroxide, keep warm for 45 min, then heat it to 85 °C and continue the reaction for 0.5 h. After the reaction is completed, a transparent cationic etherified starch aqueous solution is obtained.

[0029] (5) Add 160g of cationic etherified starch aqueous solution into a four-necked reaction bottle with temperature and mechanical stirring, heat the water bath to 70℃, drip hydrogen peroxide and potassium persulfate aqueous solution, keep dripping, add 20g of high-flexibility flame retardant monomer and 50g of styrene, carry out first polymerization reaction for 1h, then add 25g of butyl acrylate and 5g of acrylic acid, carry out repolymerization reaction for 1h, and complete the dripping of hydrogen peroxide and potassium persulfate aqueous solution at the same time of the completion of the repolymerization reaction. Continue to keep warm for 3h. After the reaction is completed, adjust the pH of the reaction liquid to 8 with ammonia water to obtain a slightly yellowish milky white styrene-acrylic emulsion, which is an intrinsic flame retardant high-elasticity styrene-acrylic emulsion. The mass concentration of hydrogen peroxide is 3%, and the amount is 50g; the amount of potassium persulfate is 5g, and the concentration of the potassium persulfate aqueous solution is 20%. Example 2

[0030] (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).

[0031] (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).

[0032] (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.

[0033] (4) Add 60 g of starch and 120 g of water into a four-necked reaction bottle with heating and mechanical stirring, heat it to 55 °C in a water bath, add an appropriate amount of ammonia water to adjust the pH value to about 9, then add 10 g of etherifying agent 2,3-epoxypropyltrimethylammonium chloride, keep warm and stir for 1.5 h, then add 45 g of hydrogen peroxide, continue to keep warm for 45 min, then heat it to 85 °C and continue to react for 0.5 h. After the reaction is completed, a transparent cationic etherified starch aqueous solution is obtained.

[0034] (5) Add 180 g of cationic etherified starch aqueous solution into a four-necked reaction bottle with temperature and mechanical stirring, heat the water bath to 70°C, drop hydrogen peroxide and potassium persulfate aqueous solution, keep dropping, add 40 g of high-flexibility flame retardant monomer and 35 g of styrene, carry out first polymerization for 1.5 h, then add 20 g of butyl acrylate and 5 g of acrylic acid, carry out repolymerization for 1.5 h, and complete the dropwise addition of hydrogen peroxide and potassium persulfate aqueous solution at the same time as the repolymerization is completed. Continue to keep warm for 3 h after the dropwise addition is completed. After the reaction is completed, adjust the pH of the reaction liquid to 8 with ammonia water to obtain a slightly yellowish milky white styrene-acrylic emulsion, which is an intrinsic flame retardant high-elasticity styrene-acrylic emulsion. The mass concentration of hydrogen peroxide is 3%, and the amount is 60 g; the amount of potassium persulfate is 6 g, and the concentration of the potassium persulfate aqueous solution is 10%. Example 3

[0035] Bisphenol A-bis(diphenyl phosphate) (BDP), resorcinol (diphenyl phosphate) (RDP), ammonium polyphosphate type II (APP), piperazine pyrophosphate (PPAP), 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 to prepare a mixture of the above materials with a total mass of 15.0 g and add the mixture to a blending container, then add 26 g of the intrinsically flame-retardant high-elastic styrene-acrylic emulsion of Example 1 of the present invention, 15 g of water, 0.4 g of an emulsifier and 0.4 g of a defoaming agent, and stir and disperse them evenly to obtain a flame-retardant coating adhesive.

[0036] 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 98.8g (i.e., the coating mass of each square meter of cloth was 98.8g). Example 4

[0037] Bisphenol A-bis(diphenyl phosphate) (BDP), resorcinol (diphenyl phosphate) (RDP), ammonium polyphosphate type II (APP), piperazine pyrophosphate (PPAP), aluminum hydroxide, triazine carbon former (CFA), and epoxy resin are prepared according to a mass ratio of 3.5:2.0:2.0:3.0:2.5:2.0:2.0 to prepare a mixture of the above materials with a total mass of 15.0 g and add the mixture to a blending container, then add 26 g of traditional commercially available 716 acrylic emulsion, 15 g of water, 0.4 g of emulsifier and 0.4 g of defoamer, stir and disperse evenly to obtain a flame retardant coating adhesive (the formula does not contain the intrinsic flame retardant high elastic styrene acrylic emulsion of the present invention).

[0038] 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 2) with a gram weight gain of 100.6g (i.e., the coating mass of each square meter of cloth was 100.6g). Example 5

[0039] Bisphenol A-bis(diphenyl phosphate) (BDP), resorcinol (diphenyl phosphate) (RDP), ammonium polyphosphate type II (APP), piperazine pyrophosphate (PPAP), 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 to prepare a mixture of the above materials with a total mass of 15.0 g and add the mixture to a blending container, then add 26 g of the intrinsically flame-retardant high-elastic styrene-acrylic emulsion of Example 2 of the present invention, 15 g of water, 0.4 g of an emulsifier and 0.4 g of a defoaming agent, and stir and disperse them evenly to obtain a flame-retardant coating adhesive.

[0040] 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 gain of 99.6g (i.e., the coating mass of each square meter of cloth was 99.6g).

[0041] From the experience of hand feeling, samples 1 and 3 added with the intrinsic flame retardant high elastic styrene acrylic emulsion of the present invention are obviously soft due to the presence of flexible segments such as cardanol; while sample 2 without adding is harder. In practical applications, the softer the fabric, the more it meets market demand. Softness ranking: sample 3> sample 1, and far> sample 2.

[0042] Referring to the BS5852 flame retardant test standard, cover the samples 1, 2 and 3 with the specified polyurethane sponge respectively, and place them under the specified burner to ignite, with the butane flame height of 35mm. After the flame is stable for 30s, continue to burn the sample with the flame for 20s to test the flame retardant performance of the sample. The test results are shown in Table 1.

[0043]

[0044] It can be clearly seen from the table that the flame retardant coating adhesive to which the intrinsically flame retardant high elastic styrene acrylic emulsion provided by the present invention is added has an obvious flame retardant effect.

[0045] 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 an intrinsically flame-retardant highly elastic styrene-acrylic emulsion, 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; then, the phosphorus-nitrogen integrated functional compound modified by chlorination is reacted with phenolic hydroxy cardanol to prepare a highly flexible flame retardant monomer; finally, the highly flexible flame retardant monomer, styrene, butyl acrylate and acrylic acid are reacted in a cationic etherified starch aqueous solution to prepare an intrinsically flame retardant high-elastic styrene-acrylic emulsion.

2. The method for preparing the intrinsically flame-retardant high-elastic styrene-acrylic emulsion 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 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 -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 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 drying, a solid-liquid separation is performed to obtain a product solution. After removing the solvent from the product solution, a light yellow viscous liquid is obtained, which is a highly flexible flame retardant monomer; (4) Mix starch and water, heat the water bath to 40-60°C, add ammonia water to adjust the pH value to 8.5-10, add etherifying agent, keep warm and stir for 1-2 hours, then add hydrogen peroxide, keep warm for 30-60 minutes, then heat to 70-90°C and continue to react for 0.3-1 hour. After the reaction is completed, a transparent cationic etherified starch aqueous solution is obtained; (5) The temperature of the cationic etherified starch aqueous solution is raised to 60-85°C in a water bath, and an aqueous solution of hydrogen peroxide and potassium persulfate is added dropwise, and the addition is maintained. A highly flexible flame retardant monomer and styrene are added to carry out a first polymerization reaction for 0.5-2h, and then butyl acrylate and acrylic acid are added to carry out a repolymerization reaction for 0.5-2h. At the end of the repolymerization reaction, the aqueous solution of hydrogen peroxide and potassium persulfate is added dropwise. After the addition is completed, the reaction is continued at a temperature of 2-4h. After the reaction is completed, the pH of the reaction solution is adjusted to 6-8 with aqueous ammonia to obtain a slightly yellowish milky white styrene-acrylic emulsion, which is an intrinsically flame retardant and highly elastic styrene-acrylic emulsion.

3. The method for preparing the intrinsically flame-retardant high-elastic styrene-acrylic emulsion 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 the intrinsically flame-retardant high-elastic styrene-acrylic emulsion 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.

5. The method for preparing the intrinsically flame-retardant high-elastic styrene-acrylic emulsion 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.

6. The method for preparing the intrinsically flame-retardant high-elastic styrene-acrylic emulsion 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.

7. The method for preparing the intrinsically flame-retardant high-elastic styrene-acrylic emulsion 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, and the amount of triethylamine used is 0.5-1.2 times the mass of phenolic hydroxy cardanol.

8. The method for preparing the intrinsically flame-retardant high-elastic styrene-acrylic emulsion according to claim 2, characterized in that: In the step (4), the mass ratio of starch to water is 1:1-1:4, the etherifying agent is 2,3-epoxypropyltrimethylammonium chloride or ‌3-chloro-2-hydroxypropyltrimethylammonium chloride, the amount of the etherifying agent is 5%-20% of the mass of the starch, the concentration of the hydrogen peroxide is 2-3%, and the amount of the hydrogen peroxide is 0.5-2 times the mass of the starch.

9. The method for preparing the intrinsically flame-retardant high-elastic styrene-acrylic emulsion according to claim 2, characterized in that: In the step (5), the amount of the high-flexibility flame-retardant monomer is 10%-30% of the mass of the cationic etherified starch aqueous solution, the amount of styrene is 0.5-5 times the mass of the high-flexibility flame-retardant monomer, the amount of butyl acrylate is 0.3-2 times the mass of the high-flexibility flame-retardant monomer, and the amount of acrylic acid is 0.05-0.5 times the mass of the high-flexibility flame-retardant monomer; the amount of potassium persulfate is 2%-10% of the total mass of the high-flexibility flame-retardant monomer, styrene, butyl acrylate, and acrylic acid; the concentration of the hydrogen peroxide is 2-3%, and the amount is 0.3-1 times the total mass of the high-flexibility flame-retardant monomer, styrene, butyl acrylate, and acrylic acid.

10. The method for preparing the intrinsically flame-retardant high-elastic styrene-acrylic emulsion 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.

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