A bio-based phosphorus-containing antibacterial flame retardant as well as a preparation method and application thereof

Abstract

The application discloses a kind of bio-based phosphorus-containing antibacterial flame retardant and its preparation method and application, wherein, preparation method includes the following steps: P-H bond-containing compound is heated and melted, then dimethylacetamide solution of natural product hydroxyl cinnamic acid derivative is dropped, and reaction is carried out by heating;After reaction is completed, purification is carried out, and bio-based phosphorus-containing antibacterial flame retardant is obtained.The preparation method provided in the application is simple, and when the bio-based phosphorus-containing antibacterial flame retardant prepared is applied to polyamide fabric, a high molecular flame-retardant antibacterial agent film can be formed on the surface of polyurethane fabric, thereby excellent flame-retardant performance, bacteriostatic performance and washing resistance are shown.

Description

Technical Field

[0001] This invention belongs to the field of fabric flame retardant technology, specifically relating to a bio-based phosphorus-containing antibacterial flame retardant, its preparation method, and its application. Background Technology

[0002] According to statistics from the Fire and Rescue Bureau of the Ministry of Emergency Management of China, 1.324 million residential fires occurred nationwide in the past 10 years, resulting in 11,634 deaths, 6,738 injuries, and direct property losses of 7.77 billion yuan. Fire poses a huge threat to human health and property safety. Textiles are among the most noteworthy items in residential fires, occupying a large portion of living space. This is also a major cause of household fires and their spread. With the continuous development of society and the economy, the variety of textiles has gradually increased. The potential fire hazards posed by some textiles lacking flame-retardant properties are also constantly increasing. How to address the shortcomings of textiles, such as their flammability and melting dripping, reduce the risk of combustion, and minimize the generation of toxic gases during combustion to protect personal and property safety has become an important research topic in the textile production field.

[0003] With the rapid development of science and technology, textiles are playing an increasingly important role in human life. Single flame-retardant textiles are increasingly unable to meet the mainstream development trend of textile differentiation and multifunctionality, urgently requiring the development of functional textile products that maintain their inherent excellent properties while also being flame-retardant. Antibacterial properties are also a crucial function for textiles. Due to their microporous structure, textiles provide a suitable growth environment for microorganisms, including the wearer's body temperature, moisture emitted by the body, and skin metabolites. This makes textiles an ideal breeding ground for bacteria and fungi. Antibacterial textiles can provide antibacterial and anti-mildew functions to commonly used textiles, maintaining cleanliness and hygiene. They not only prevent fabrics from being contaminated and damaged by microorganisms, but also effectively eliminate the unpleasant odors produced by the decomposition of organic matter by pathogens in textiles, protecting them from mold and deterioration. More importantly, they prevent the spread of infectious diseases, ensure human safety and health, provide comfort, and reduce the rate of cross-infection in public environments.

[0004] Polyamide fabrics are an important class of textile materials, first synthesized by DuPont, and subsequently gained market share due to their superior performance. However, polyamide textiles lack flame retardant and antibacterial properties, making them unsuitable for certain applications or conditions, such as medical protective equipment, outdoor military supplies, and home decorations. Therefore, improving the flame retardant and antibacterial properties of polyamide textiles is of significant practical importance. However, traditional flame retardants no longer align with the trend of green development, and some flame retardants suffer from cumbersome and difficult preparation processes.

[0005] Chinese patent CN116479541A proposes a polyamide 6 composite fiber with flame retardant and antibacterial properties, which is made of copper-zinc bimetallic organic framework material (Cu-Zn-ZIF) and matrix (nylon 6). This patent mainly prepares polyamide 6 composite fibers with flame retardant and antibacterial properties through blending, and the preparation process is complex and cumbersome.

[0006] Chinese patent CN116217623A proposes a method for preparing a biomass-based flame retardant. This biomass-based flame retardant can impart good flame retardant and antibacterial properties to polyamide fabrics, but the preparation time is long and the raw materials have an irritating odor.

[0007] Reference 1 (ACS Applied Engineering Materials, 2022, 1(1): 268-277.) prepared a water-based flame-retardant, antibacterial, and UV-resistant coating using taurine and tannic acid, and applied it to polyamide 6 fabrics via surface modification. However, the limiting oxygen index of the modified flame-retardant polyamide remained low, and the coating lacked washability. Currently, washability remains a major challenge in the flame-retardant modification of polyamide textiles.

[0008] Therefore, it is of great significance to study a bio-based durable phosphorus-containing polymer flame-retardant and antibacterial coating and use it to prepare functionalized polyamide fabrics. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bio-based phosphorus-containing antibacterial flame retardant, its preparation method and application. The preparation method is simple. When the prepared bio-based phosphorus-containing antibacterial flame retardant is applied to polyamide fabrics, it can form a polymer flame retardant and antibacterial film on the surface of polyurethane fabrics, thereby exhibiting excellent flame retardant properties, antibacterial properties and water-washing resistance.

[0010] This invention provides the following technical solution:

[0011] In a first aspect, a method for preparing a bio-based phosphorus-containing antibacterial flame retardant is provided, comprising the following steps:

[0012] The compound containing pH bonds is heated to melt, and then a dimethylacetamide solution of a natural product hydroxycinnamic acid derivative is added dropwise, followed by heating to carry out the reaction.

[0013] After the reaction is complete, the product is purified to obtain a bio-based phosphorus-containing antibacterial flame retardant.

[0014] Furthermore, the PH-containing compound is one of dimethyl phosphite, diethyl phosphite, or 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO).

[0015] Furthermore, the natural product hydroxycinnamic acid derivative is one of p-coumaric acid, ferulic acid, and caffeic acid.

[0016] Furthermore, the concentration of the dimethylacetamide (DMAC) solution of the natural product hydroxycinnamic acid derivative is 25–40 wt%.

[0017] Furthermore, the molar ratio of the PH-bonded compound to the natural product hydroxycinnamic acid derivative is 1:1.

[0018] Furthermore, the heating reaction temperature is 130–160°C, and the reaction time is 8–12 h; the purification method includes: removing the solvent by rotary evaporation, and then recrystallizing the reaction product with ethanol.

[0019] In a second aspect, a bio-based phosphorus-containing antibacterial flame retardant is provided, which is prepared using the method described in the first aspect.

[0020] Thirdly, the application of the bio-based phosphorus-containing antibacterial flame retardant described in the second aspect in improving the flame retardancy and antibacterial properties of polyamide fabrics is provided, including:

[0021] A bio-based phosphorus-containing antibacterial flame retardant and catalyst were dissolved in a mixed solvent of ethanol and water, and the pH was adjusted with acetic acid to obtain a flame retardant solution.

[0022] Polyamide fabrics are treated with a flame retardant solution by padding, and then dried and baked to form a polymer flame retardant and antibacterial film on the surface of the polyamide fabrics.

[0023] Furthermore, the catalyst is sodium hypophosphite, and the amount of the catalyst used is 5-10% mol of the bio-based phosphorus-containing antibacterial flame retardant; the volume ratio of ethanol to water in the mixed solvent of ethanol and water is (2-1):1; acetic acid is used to adjust the pH to 3-5; and the concentration of the bio-based phosphorus-containing antibacterial flame retardant in the flame retardant solution is 25-50 g / L.

[0024] Furthermore, the padding method employs a two-dip, two-roll process, with an immersion time of 10-20 minutes and a roll-off rate of 70-90%; the drying temperature is 70-90°C; and the baking temperature is 150-170°C, with a baking time of 10-30 minutes.

[0025] Furthermore, the polyamide fabric is one of polyamide 6 fabric, polyamide 66 fabric, and polyamide 56 fabric.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) This invention uses a solution of dimethylacetamide containing a PH bond compound and a natural product hydroxycinnamic acid derivative as raw materials. The PH bond is added to the C=C bond through a Michael addition reaction to prepare a novel bio-based phosphorus-containing antibacterial flame retardant. The polymer is then polymerized under high temperature and catalysis to form a polymer flame retardant and antibacterial film that is coated on the surface of polyamide fabric. The bio-based phosphorus-containing antibacterial flame retardant mainly improves the flame retardant performance of polyamide fabric through a gas-phase mechanism. The PO· and PO2· generated by the PH bond compound and the phenoxy free radical generated by natural hydroxycinnamic aldehyde synergistically enhance the quenching effect to make the burning polyamide fabric quickly self-extinguish, thereby achieving a flame retardant effect. The flame retardant performance is: damaged length 9-13cm, limiting oxygen index 29-33%;

[0028] (2) The bio-based phosphorus-containing antibacterial flame retardant prepared in this invention adheres and crosslinks to the surface of polyamide fabric, further restricting the flow of polyamide melt. Therefore, the functionalized polyamide has an anti-dripping effect.

[0029] (3) In this invention, the bio-based phosphorus-containing antibacterial flame retardant forms a polymer flame retardant and antibacterial agent film on the surface of polyamide fabric. On the one hand, it helps to improve the fastness of the bio-based phosphorus-containing antibacterial flame retardant, thereby giving the polyamide fabric better fastness and further improving the water resistance of the polyamide fabric. After 30 to 40 water washes, the polyamide fabric still does not drip during the burning process. On the other hand, because its structure is rich in oxygen negative ions, these ions can bind to the cell membrane of Staphylococcus aureus and further destroy the cell nucleus, thereby achieving the bactericidal and antibacterial effect. The antibacterial rate against Staphylococcus aureus reaches 91 to 94%.

[0030] (4) The PH bond compounds and natural hydroxycinnamic acid derivatives used in this invention are all environmentally friendly raw materials. The preparation method is simple. The prepared bio-based phosphorus-containing antibacterial flame retardant will not cause pollution or harm to human health when applied to polyamide fabrics. Attached Figure Description

[0031] Figure 1 The synthesis route of the polymer flame retardant and antibacterial agent in Example 1 of this invention;

[0032] Figure 2 The surface morphology of the functionalized polyamide 6 fabric in Example 1 of this invention;

[0033] Figure 3 The small molecule flame retardant in Example 1 of this invention 1 H NMR spectrum;

[0034] Figure 4 The small molecule flame retardant in Example 1 of this invention 31 P NMR spectrum;

[0035] Figure 5 The flame retardant performance test results are for the untreated polyamide 66 fabric in Example 2 of this invention.

[0036] Figure 6 The flame retardant performance test results of the functional polyamide 66 fabric in Example 2 of this invention;

[0037] Figure 7 The antibacterial properties of the untreated polyamide 56 fabric against Staphylococcus aureus in Example 3 of this invention;

[0038] Figure 8 This demonstrates the antibacterial properties of the functionalized polyamide 56 fabric against Staphylococcus aureus in Example 3 of the present invention. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0040] The testing methods for the performance indicators involved in the following embodiments are as follows:

[0041] (1) Damage length: The damage length of polyamide fabrics was tested using ASTM D6413-15;

[0042] (2) Limiting oxygen index: The limiting oxygen index of polyamide fabrics was tested using ASTM D2863-17.

[0043] (3) Washing performance: The polyamide fabric was washed according to the AATCC 61-2013 washing standard;

[0044] (4) Antibacterial properties: The antibacterial properties of polyamide fabrics were tested according to GB / T 20944.3-2008.

[0045] Example 1

[0046] This embodiment provides a method for preparing and applying a bio-based phosphorus-containing antibacterial flame retardant, the specific steps of which are as follows:

[0047] (1) Place 0.1 mol DOPO (21.6 g) in a three-necked flask and heat it to 140 °C under nitrogen protection to melt it.

[0048] (2) Dissolve 0.1 mol of p-coumaric acid (16.4 g) in 27 ml of DMAC to obtain a DMAC solution of DOPO.

[0049] (3) The DMAC solution of DOPO was added dropwise to a three-necked flask at a rate of 0.5 ml / min. The mixture was stirred and reacted at 140 °C for 9 h. After the reaction was completed, the DMAC was removed by rotary evaporation, and the reaction product was recrystallized with ethanol to obtain a small molecule flame retardant (i.e., a bio-based phosphorus-containing antibacterial flame retardant).

[0050] (4) Dissolve the small molecule flame retardant and 5% mol of sodium hypophosphite in a mixture of water and ethanol (volume ratio of ethanol to water is 1:1) to prepare a flame retardant solution with a concentration of 40 g / L and a pH value of 4.

[0051] (5) Functionalized polyamide 6 fabric was prepared by pad-bake method. The polyamide 6 fabric was immersed in the flame retardant solution obtained in step (4) for 15 min, and then padded once (with a padding rate of 80%). The above operation was repeated (two dips and two pads). The treated polyamide 6 fabric was pre-dried at 80°C for 3 min, and then baked at 160°C for 10 min, so that the small molecule flame retardant polymerized into a high molecular flame retardant and antibacterial agent and formed a film on the fiber surface of the polyamide 6 fabric.

[0052] The flame retardant properties of the functionalized polyamide 6 fabric are as follows: damaged length 10.5cm, limiting oxygen index 31.2%, no melt dripping during combustion, no melt dripping after 30 washes, and a 93.3% inhibition rate against Staphylococcus aureus.

[0053] Figure 1 This describes the synthetic route for polymeric flame retardant and antibacterial agents.

[0054] Figure 2 The figure shows the surface morphology of the functionalized polyamide 6 fabric in Example 1. A thin film is attached to the surface of the polyamide 6 fabric, which confirms that the small molecule flame retardant has polymerized into a high molecular flame retardant and antibacterial agent.

[0055] Figure 3 The figure shows the hydrogen spectrum of the small molecule flame retardant in Example 1. The peaks from 6.5 to 8.2 ppm represent hydrogen vibrations in the biphenyl ring of the flame retardant, while the remaining peaks are caused by hydrogen vibrations in -CH2 and -CH, respectively. Notably, no shift peaks were observed in the PH bond of DOPO or the CH2=CH double bond of coumaric acid, confirming the successful synthesis of the small molecule flame retardant.

[0056] Figure 4 The phosphorus spectrum of the small-molecule flame retardant reveals only one phosphorus shift peak, which perfectly corresponds to the structure of the small-molecule flame retardant. From Figures 2-4 The data shows that small molecule flame retardants were successfully synthesized and successfully polymerized and adsorbed on the fabric surface.

[0057] Example 2

[0058] This embodiment provides a method for preparing and applying a bio-based phosphorus-containing antibacterial flame retardant, the specific steps of which are as follows:

[0059] (1) Place 0.1 mol of diethyl phosphite (13.8 g) in a three-necked flask and heat it to 130 °C under nitrogen protection.

[0060] (2) Dissolve 0.1 mol ferulic acid (19.4 g) in 35 ml of DMAC to obtain a DMAC solution of ferulic acid.

[0061] (3) The DMAC solution of ferulic acid was added dropwise to a three-necked flask at a rate of 0.7 ml / min. The mixture was stirred and reacted at 130 °C for 12 h. After the reaction was completed, the DMAC was removed by rotary evaporation, and the reaction product was recrystallized with ethanol to obtain a small molecule flame retardant.

[0062] (4) Dissolve the small molecule flame retardant and sodium hypophosphite accounting for 6% mol of the small molecule flame retardant in a mixture of water and ethanol (volume ratio of ethanol to water is 3:2) to prepare a flame retardant solution with a concentration of 50 g / L and a pH value of 3.

[0063] (5) Functionalized polyamide 66 fabric was prepared by pad-bake method. The polyamide 66 fabric was immersed in the flame retardant solution obtained in step (4) for 10 min, and then padded once (with a padding rate of 70%). The above operation was repeated (two dips and two pads). The treated polyamide 66 fabric was pre-dried at 90°C for 3 min, and then baked at 150°C for 30 min, so that the small molecule flame retardant polymerized into a high molecular flame retardant and antibacterial agent and formed a film on the surface of the polyamide 66 fabric fibers.

[0064] The flame retardant properties of the functionalized polyamide 66 fabric are as follows: damaged length 9.0 cm, limiting oxygen index 33.0%, no melt dripping during combustion, no melt dripping after 40 washes, and an antibacterial rate of 94.0% against Staphylococcus aureus.

[0065] Figure 5 The image shows a vertical burning pattern of untreated polyamide 66 fabric, with a damaged length of 16.7 cm.

[0066] Figure 6 The image shows a vertical burning diagram of functionalized polyamide 66 fabric. The damaged length of the functionalized polyamide 66 was reduced to 9.0 cm, and no molten droplets were observed during the burning process, demonstrating that the functionalization method can effectively reduce the fire hazard of polyamide 66 fabric.

[0067] Example 3

[0068] This embodiment provides a method for preparing and applying a bio-based phosphorus-containing antibacterial flame retardant, the specific steps of which are as follows:

[0069] (1) Place 0.1 mol of dimethyl phosphite (11.0 g) in a three-necked flask and heat it to 160 °C under nitrogen protection to melt it.

[0070] (2) Dissolve 0.1 mol of caffeic acid (16.4 g) in 50 ml of DMAC to obtain a DMAC solution of caffeic acid.

[0071] (3) The DMAC solution of caffeic acid was added dropwise to a three-necked flask at a rate of 0.6 ml / min. The mixture was stirred and reacted at 160 °C for 8 h. After the reaction was completed, the DMAC was removed by rotary evaporation, and the reaction product was recrystallized with ethanol to obtain a small molecule flame retardant.

[0072] (4) Dissolve the small molecule flame retardant and sodium hypophosphite accounting for 7% mol of the small molecule flame retardant in a mixture of water and ethanol (volume ratio of ethanol to water is 2:1) to prepare a flame retardant solution with a concentration of 25 g / L and a pH value of 5.

[0073] (5) Functionalized polyamide 56 fabric was prepared by pad-bake method. The polyamide 56 fabric was immersed in the flame retardant solution obtained in step (4) for 20 min, and then padded once (with a padding rate of 90%). The above operation was repeated (two dips and two pads). The treated polyamide 6 fabric was pre-dried at 70°C for 3 min, and then baked at 170°C for 10 min, so that the small molecule flame retardant polymerized into a high molecular flame retardant and antibacterial agent and formed a film on the surface of the polyamide 56 fabric fibers.

[0074] The flame retardant properties of the prepared functionalized polyamide are as follows: damaged length 13.0 cm, limiting oxygen index 29.0%, no molten dripping during combustion, and no molten dripping during combustion even after 30 water washes. The antibacterial rate against Staphylococcus aureus reaches 91.0%.

[0075] Figure 7 The test results for the untreated polyamide 56 fabric against Staphylococcus aureus are shown in the figure, where obvious and numerous colonies can be observed.

[0076] Figure 8 The test results for the anti-Staphylococcus aureus effect of the functionalized polyamide 56 fabric shown are compared with... Figure 7 compared to, Figure 8 The number of bacterial colonies was significantly reduced, and calculations showed that the functionalized polyamide 56 had an inhibition rate of 91.0% against Staphylococcus aureus.

[0077] Example 4

[0078] This embodiment provides a method for preparing and applying a bio-based phosphorus-containing antibacterial flame retardant, the specific steps of which are as follows:

[0079] (1) Place 0.1 mol DOPO (21.6 g) in a three-necked flask and heat it to 150 °C under nitrogen protection to melt it.

[0080] (2) Dissolve 0.1 mol of caffeic acid (18.0 g) in 40 ml of DMAC to obtain a DMAC solution of caffeic acid.

[0081] (3) The DMAC solution of caffeic acid was added dropwise to a three-necked flask at a rate of 0.5 ml / min. The mixture was stirred and reacted at 150 °C for 10 h. After the reaction was completed, the DMAC was removed by rotary evaporation, and the reaction product was recrystallized with ethanol to obtain a small molecule flame retardant.

[0082] (4) Dissolve the small molecule flame retardant and 5.5% mol of sodium hypophosphite in a mixture of water and ethanol (volume ratio of ethanol to water is 4:3) to prepare a flame retardant solution with a concentration of 30 g / L and a pH value of 4.5.

[0083] (5) Functionalized polyamide 6 fabric was prepared by pad-baking method. The polyamide 6 fabric was immersed in the flame retardant solution obtained in step (4) for 15 min, and then rolled once (with a roll rate of 85%). The above operation was repeated (two dips and two rolls). The treated polyamide 6 fabric was pre-dried at 85°C for 3 min, and then baked at 150°C for 20 min, so that the small molecule flame retardant polymerized into a high molecular flame retardant and antibacterial agent and formed a film on the surface of the polyamide 6 fabric fibers.

[0084] The flame retardant properties of the prepared functionalized polyamide are as follows: damaged length 11.8 cm, limiting oxygen index 32.4%, no molten dripping during combustion, and no molten dripping during combustion even after 30 water washes. The antibacterial rate against Staphylococcus aureus reaches 92.8%.

[0085] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a bio-based phosphorus-containing antibacterial flame retardant, characterized in that, Includes the following steps: The compound containing the pH bond is heated to melt, and then a dimethylacetamide solution of the natural product hydroxycinnamic acid derivative is added dropwise. The reaction is carried out by heating at a temperature of 130~160℃ for 8~12h. After the reaction is complete, the product is purified to obtain a bio-based phosphorus-containing antibacterial flame retardant. The PH-containing compound is one of dimethyl phosphite, diethyl phosphite, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; The natural product hydroxycinnamic acid derivative is one of p-coumaric acid, ferulic acid, and caffeic acid.

2. The method for preparing the bio-based phosphorus-containing antibacterial flame retardant according to claim 1, characterized in that, The concentration of the dimethylacetamide solution of the natural product hydroxycinnamic acid derivative is 25-40 wt%.

3. The method for preparing the bio-based phosphorus-containing antibacterial flame retardant according to claim 1, characterized in that, The molar ratio of the PH-bonded compound to the natural product hydroxycinnamic acid derivative is 1:

1.

4. The method for preparing the bio-based phosphorus-containing antibacterial flame retardant according to claim 1, characterized in that, The purification method includes: removing the solvent by rotary evaporation, and then recrystallizing the reaction product with ethanol.

5. A bio-based phosphorus-containing antibacterial flame retardant, characterized in that, It is prepared by the method described in any one of claims 1 to 4.

6. The application of the bio-based phosphorus-containing antibacterial flame retardant of claim 5 in improving the flame retardancy and antibacterial properties of polyamide fabrics, characterized in that, include: A bio-based phosphorus-containing antibacterial flame retardant and the catalyst sodium hypophosphite were dissolved in a mixed solvent of ethanol and water, and the pH was adjusted with acetic acid to obtain a flame retardant solution. Polyamide fabrics are treated with a flame retardant solution by padding, and then dried and baked to form a polymer flame retardant and antibacterial film on the surface of the polyamide fabrics.

7. The application of the bio-based phosphorus-containing antibacterial flame retardant according to claim 6, characterized in that, The amount of catalyst used is 5-10% mol of the bio-based phosphorus-containing antibacterial flame retardant; the volume ratio of ethanol to water in the mixed solvent of ethanol and water is (2-1):1; the pH is adjusted to 3-5 with acetic acid; the concentration of the bio-based phosphorus-containing antibacterial flame retardant in the flame retardant solution is 25-50 g / L.

8. The application of the bio-based phosphorus-containing antibacterial flame retardant according to claim 6, characterized in that, The immersion and rolling method employs a two-dip, two-roll process, with an immersion time of 10-20 minutes and a roll-off rate of 70-90%. The drying temperature is 70-90℃, and the baking temperature is 150-170℃ for 10-30 minutes.

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