A bio-based flame retardant co-agent, modified fabric and method of making the same

Abstract

The application discloses a kind of bio-based flame retardant auxiliary, modified fabric and its preparation method, the flame retardant auxiliary includes by the material made of the substance with formula (I) shown structure and bio-based monomer occurs substitution reaction;In formula (I), n is greater than or equal to 10;Bio-based monomer includes 20mol%‑65mol% first monomer and 35mol%‑80mol% second monomer with mole percentage content, first monomer is aromatic compound with aldehyde group and hydroxyl group, second monomer is compound with hydroxyl group and carbon number greater than or equal to 5 fatty chain segment;In the process of substitution reaction, bio-based monomer is added in the form of metal salt;When applied to modified fabric, it can be pretreated to give active site to fabric, then combine with each other;Practice shows that the flame retardant auxiliary of the application can give modified fabric excellent durable stability, and can synergistically realize excellent flame retardant, hydrophobic and good flexibility and the like performance.

Description

Technical Field

[0001] This invention relates to the field of fabric modification technology, and more particularly to modifying auxiliaries to impart better flame retardant, hydrophobic and other properties to fabrics. Specifically, it relates to a bio-based flame retardant auxiliary, modified fabric and its preparation method. Background Technology

[0002] Conventional textile materials are generally flammable, easily causing fires and posing significant fire safety hazards. Coating the surface of textiles with flame-retardant additives is an effective way to improve their flame-retardant properties and reduce fire risk. Meanwhile, textiles are easily stained by water and dirt during daily use, affecting their appearance and potentially increasing weight, reducing breathability, and even accelerating aging due to water absorption. Therefore, textiles possessing both hydrophobic and flame-retardant properties are of significant practical importance, and textiles with both functions are expected to be widely used in critical areas such as clothing, home furnishings, and fire protection. However, traditional petrochemical-based functional additives (such as halogenated flame retardants and fluorinated hydrophobic finishing agents) generally have poor biodegradability and release toxic gases upon combustion, seriously endangering human health and the ecological environment.

[0003] Driven by the concept of green environmental protection, renewable and biodegradable bio-based materials are gradually becoming a research trend in the field of functional textile finishing. However, existing technologies have obvious shortcomings. For example, patent CN107747239A discloses a technology that adds flame-retardant treated cellulose powder to dye liquor and transfers the powder to the fabric surface through the dyeing process to achieve flame retardancy. Although the preparation is simple, it has core defects: the flame-retardant powder and the fabric only physically adhere, resulting in poor adhesion and water resistance; it does not take into account hydrophobic properties; and the powder easily causes the fabric to feel stiff and reduce its flexibility. Another example is patent CN116770587A, which discloses a double-layer bio-based composite coating technology for the fabric surface. It achieves synergy through a bottom flame-retardant and antibacterial coating and a top hydrophobic flame-retardant coating. However, it suffers from complex coating structure and cumbersome preparation steps. Moreover, the superimposed double coating easily leads to a decrease in the breathability of the fabric, limiting its practical application. Furthermore, the coating formed by impregnation has insufficient durability and is prone to peeling off during washing or repeated storage, folding, and use.

[0004] Therefore, developing a bio-based flame retardant additive with a simple coating structure, easy preparation process, strong adhesion to fabrics, and the ability to synergistically achieve excellent flame retardancy, hydrophobicity, and good flexibility has become a key direction for overcoming the pain points of existing technologies and promoting the green and sustainable development of the field of functional fabric finishing.

[0005] It should be noted that the information disclosed in the background section above is only for understanding the background of this application. Therefore, the background section of this invention may include background information about the problems or environment of this invention, and is not necessarily a description of the prior art. Thus, the content included in the background section does not constitute an admission of the prior art by the applicant. Summary of the Invention

[0006] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide a new bio-based flame retardant additive that can solve at least one problem in the prior art and reduce or even avoid the occurrence of problems where one aspect is neglected while the other is addressed.

[0007] The present invention also provides an application of the above-mentioned bio-based flame retardant additive in the preparation of modified fibers or modified fabrics, which can endow the modified fibers or modified fabrics with excellent long-lasting stability and can synergistically achieve excellent flame retardant, hydrophobic and good flexibility properties.

[0008] To achieve the above objectives, the present invention employs the following technical solution: A bio-based flame retardant additive comprising a material prepared by a substitution reaction between a substance having the structure shown in formula (I) and a bio-based monomer; In equation (Ⅰ), n is greater than or equal to 10; The bio-based monomer comprises a first monomer and a second monomer. The first monomer is an aromatic compound having substituents including aldehyde and hydroxyl groups, and the second monomer is a compound having substituents including hydroxyl groups and a fatty chain segment with 5 or more carbon atoms. The fatty chain segment includes straight-chain fatty chains and / or branched fatty chains. Based on a total molar amount of 100 mol% for the first monomer and the second monomer, the first monomer accounts for 15 mol%-65 mol%, and the second monomer accounts for 35 mol%-85 mol%. During the substitution reaction, the bio-based monomer is added in the form of a metal salt.

[0009] In some embodiments of the present invention, with the total molar amount of the first monomer and the second monomer being 100 mol%, the first monomer accounts for 15 mol%-50 mol% and the second monomer accounts for 50 mol%-85 mol% of the bio-based monomer.

[0010] Furthermore, based on a total molar amount of 100 mol% for the first monomer and the second monomer, the first monomer accounts for 17 mol%-40 mol% and the second monomer accounts for 60 mol%-83 mol% of the bio-based monomer.

[0011] According to certain aspects of the present invention, the numerical range "15mol%-65mol%" includes, but is not limited to, 15mol%, 16mol%, 18mol%, 19mol%, 20mol%, 22mol%, 25mol%, 26mol%, 28mol%, 30mol%, 32mol%, 35mol%, 38mol%, 40mol%, 42mol%, 45mol%, 48mol%, 50mol%, 52mol%, 55mol%, 58mol%, 60mol%, 62mol%, 65mol%, etc.

[0012] According to certain aspects of the present invention, the numerical range "35mol%-85mol%" includes, but is not limited to, 35mol%, 38mol%, 40mol%, 42mol%, 45mol%, 48mol%, 50mol%, 52mol%, 55mol%, 58mol%, 60mol%, 62mol%, 65mol%, 66mol%, 68mol%, 70mol%, 72mol%, 75mol%, 78mol%, 80mol%, 82mol%, 85mol%, etc.

[0013] In some embodiments of the present invention, n is 10-5000.

[0014] Furthermore, n is between 20 and 2500.

[0015] According to certain aspects of the present invention, the numerical range "10-5000" includes, but is not limited to, 10, 12, 15, 18, 20, 25, 30, 35, 45, 50, 60, 70, 80, 100, 120, 150, 180, 200, 250, 300, 350, 400, 450, 480, 500, 550, 600, 650, 700, 800, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1600, 1700, 1800, 1900, 2000, 2100, 2150, 2200, 2300, 2500, 2800, 3000, 3500, 4000, 4200, 4500, 4800, 5000, etc.

[0016] In some embodiments of the present invention, the first monomer is at least one selected from the compounds shown in formula (II); In formula (II), A is a 5-10 membered aromatic ring, and R1 is selected from a single bond or C. 1-3 Alkylene, R2 is selected from one bond, C1-3 Alkylene or C 2-4 alkenyl group, R3 is selected from C 1-3 Alkoxy or C 1-3 Alkyl group, where t is 0, 1, or 2.

[0017] In this invention, "one bond" means that the groups at both ends of the intermediate group are directly connected. For example, in ABC, when B is a single bond, A and C are directly connected to form AC.

[0018] Furthermore, A is a benzene ring or a furan ring.

[0019] Furthermore, R1 is selected from a single bond, methylene or ethylene, R2 is selected from a single bond, methylene or vinylene, and R3 is selected from methoxy, ethoxy, methyl or ethyl.

[0020] According to certain specific and preferred aspects of the present invention, the first monomer is selected from one, two or more combinations of vanillin or its derivatives, eugenol or its derivatives, p-hydroxybenzaldehyde or its derivatives, sinigral or its derivatives, salicylaldehyde or its derivatives, and 5-hydroxymethylfurfural or its derivatives. These monomers are all derived from natural products; for example, vanillin is extracted from vanilla pods, and 5-hydroxymethylfurfural can be prepared by the dehydration reaction of carbohydrates such as glucose and fructose, exhibiting good biocompatibility and renewability.

[0021] According to certain specific and preferred aspects of the present invention, the second monomer is a combination of one, two or more selected from cashew nut shell oil, oleyl alcohol, ricinoleic acid, methyl ricinoleate, lauryl alcohol, stearyl alcohol, and palmitol. Cashew nut shell oil is derived from cashew nut shell oil, and ricinoleic acid is derived from castor oil; both are widely available and cost-effective bio-based raw materials.

[0022] In some embodiments of the present invention, the metal salt is a sodium salt of a bio-based monomer.

[0023] Furthermore, the sodium salt of the bio-based monomer is prepared by the following method: under the protection of a protective gas, the first monomer or the second monomer is added to an aqueous solution of metallic sodium, and the reaction is carried out by heating; wherein the molar amount of the first monomer or the second monomer added is in excess of the metallic sodium.

[0024] According to some specific aspects of the present invention, the method for preparing the sodium salt of the bio-based monomer includes: At 0-5℃ (e.g., an ice bath can be selected), under the protection of a protective gas (such as nitrogen or argon), the first monomer or the second monomer is added dropwise to an aqueous solution of metallic sodium. After the addition is complete, the temperature is raised to 25-80℃ to continue the reaction (the reaction time can be 6-24 hours) until the metallic sodium (such as filamentous metallic sodium) is completely disappeared, and the sodium salts corresponding to the first monomer or the second monomer are obtained.

[0025] Furthermore, the ratio of the molar amount of the first monomer or the second monomer to the molar amount of the metallic sodium is 1.2-1.6:1.

[0026] In some embodiments of the present invention, the substance having the structure shown in formula (I) is prepared by reacting hexachlorocyclotriphosphazene under heating conditions in the presence of a catalyst and under the protection of a protective gas to generate the substance having the structure shown in formula (I).

[0027] Furthermore, in the process of preparing a substance having the structure shown in formula (I), the catalyst is composed of aminosulfonic acid and calcium sulfate or its hydrate in a mass ratio of 1:0.1-0.12.

[0028] Furthermore, in the process of preparing a substance having the structure shown in formula (Ⅰ), the reaction is controlled to be carried out at 190-215℃.

[0029] Furthermore, in the process of preparing a substance having the structure shown in formula (I), the mass ratio of the hexachlorocyclotriphosphazene to the catalyst is 1:0.01-0.015.

[0030] Furthermore, in the preparation of the substance having the structure shown in formula (I), the reaction is controlled to proceed in a solvent, which may be a high-boiling-point solvent, for example, selected from at least one of 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, biphenyl, and tetrahydronaphthalene. Even further, the mass-to-volume ratio of hexachlorocyclotriphosphazene to the solvent is 1 g : (0.8~1.2) mL.

[0031] According to some specific aspects of the present invention, the preparation method of the substance having the structure shown in formula (I) includes: adding hexachlorocyclotriphosphazene to a solvent, adding a catalyst, and stirring the reaction at 190-215°C under a protective gas (which may be nitrogen, argon, etc.); after the reaction is completed, cooling, washing the reaction solution in excess petroleum ether until the upper liquid is colorless and transparent, collecting the precipitate to obtain a light brown elastomer, and dissolving it in an anhydrous solvent for later use. Further, the anhydrous solvent may be selected from anhydrous tetrahydrofuran, anhydrous acetonitrile, and anhydrous toluene.

[0032] In some embodiments of the present invention, the substitution reaction is controlled to be carried out at a temperature of 65-90°C, for example, at temperatures of 66°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, 90°C, etc.

[0033] In some embodiments of the present invention, the flame retardant additive is prepared by the following method: the substance having the structure shown in formula (I) is added to the metal salt corresponding to the first monomer, and after the addition is complete, the metal salt corresponding to the second monomer is added to the reaction system, and after all the addition is complete, the temperature is raised to react.

[0034] According to some specific aspects of the present invention, the method for preparing the flame retardant additive includes: A dispersion of the substance having the structure shown in formula (I) was added dropwise to the metal salt corresponding to the first monomer. After the addition was complete, the metal salt corresponding to the second monomer was added dropwise to the reaction system. After all the addition was complete, the temperature was raised to 65-90℃ for reaction. Further, after the reaction was completed, most of the anhydrous solvent was removed by rotary evaporation. The obtained product was repeatedly purified by precipitation in excess petroleum ether and water. The precipitate was collected and dried under vacuum at 60-90℃ overnight.

[0035] In some embodiments of the present invention, the dispersion of a substance having the structure shown in formula (I) can be obtained by dispersing the substance having the structure shown in formula (I) in solvents such as anhydrous tetrahydrofuran, anhydrous acetonitrile, and anhydrous toluene.

[0036] In some embodiments of the present invention, the degree of substitution of chlorine atoms on the substance having the structure shown in formula (I) in the flame retardant additive is 98%-100%.

[0037] Another technical solution provided by the present invention: a bio-based flame retardant additive, wherein the flame retardant additive has the structure shown in formula (Ⅲ); ; In equation (Ⅲ), n1, n2, and n3 are each independently greater than or equal to 0, and the sum of n1, n2, and n3 is greater than or equal to 10; and in the repeating units corresponding to n1, n2, and n3, when the total molar amount of R4 and the total molar amount of R5 are 100 mol%, R4 accounts for 15 mol%-65 mol%, and R5 accounts for 35 mol%-85 mol%; the repeating units corresponding to n1, n2, and n3 are arranged linearly in any order; R4 is the residual group after removing one hydroxyl group from the first monomer, and R5 is the residual group after removing one hydroxyl group from the second monomer. The first monomer is an aromatic compound having substituents including aldehyde and hydroxyl groups, and the second monomer is a compound having substituents including hydroxyl groups and aliphatic segments with 5 or more carbon atoms, wherein the aliphatic segments include straight-chain aliphatic chains and / or branched aliphatic chains.

[0038] Another technical solution provided by the present invention: the application of the above-mentioned bio-based flame retardant additive in the preparation of modified fibers or modified fabrics.

[0039] Another technical solution provided by the present invention: a method for preparing modified fabric, the preparation method comprising: (1) Immerse the fabric in a silane coupling agent solution, separate it after immersion, heat and solidify it to make a fabric intermediate; The silane coupling agent solution is prepared by dispersing an amino-containing silane coupling agent in a solvent. (2) The fabric intermediate is immersed in the dispersion of the above-mentioned bio-based flame retardant additive. After immersion, it is separated and heated to solidify, thus producing the modified fabric.

[0040] In some embodiments of the present invention, in step (1), the amino-containing silane coupling agent comprises N-(β-aminoethyl)-γ-aminopropyltriethoxysilane and / or γ-aminopropyltriethoxysilane.

[0041] In some embodiments of the present invention, in step (1), the solvent used in the silane coupling agent solution includes ethanol and water, and the volume ratio of ethanol to water is 1:0.8-1.2.

[0042] In some embodiments of the present invention, in step (1), the silane coupling agent solution contains 0.5%-2.0% by mass of an amino-containing silane coupling agent.

[0043] In some embodiments of the present invention, in step (1), the heating and curing process is controlled to be carried out at 120-150°C.

[0044] In some embodiments of the present invention, in step (2), the heating and curing process is controlled to be carried out at 130-150°C.

[0045] In some embodiments of the present invention, in step (2), the dispersion of the bio-based flame retardant is obtained by dispersing the bio-based flame retardant in a composite solvent. Further, the composite solvent is composed of a first organic solvent, a second organic solvent, and water, wherein the volume ratio of the first organic solvent, the second organic solvent, and the water is 2-4:0.8-1.2:1. The first organic solvent is at least one selected from tetrahydrofuran, acetonitrile, dichloromethane, and trichloromethane, and the second organic solvent is an alcohol solvent, such as ethanol. This composite solvent system balances the solubility and environmental friendliness of the bio-based flame retardant; the organic solvent ensures complete dissolution of the additive, while the introduction of ethanol and water reduces the overall toxicity of the solvent and simultaneously improves the wettability of the solvent on the fabric.

[0046] In some embodiments of the present invention, in step (2), the mass percentage of the bio-based flame retardant in the dispersion of the bio-based flame retardant is 5%-15%.

[0047] In some embodiments of the present invention, step (2) is performed as follows: the fabric intermediate is immersed in the dispersion of the above-mentioned bio-based flame retardant additive. After immersion, it is removed and pre-dried at 80-100°C, and then cured at 130-150°C. According to the present invention, the pre-drying step is beneficial to slowly remove the solvent from the fabric, avoiding the formation of bubbles and cracks in the coating that may be caused by rapid evaporation of the solvent during the curing process.

[0048] In some embodiments of the present invention, the fabric is spun from one or more selected from polyester fiber, cotton fiber, linen fiber, viscose fiber, and polyester-cotton blended fiber.

[0049] According to the present invention, during the preparation of the modified fabric, the fabric is immersed in a silane coupling agent solution, which allows the silane coupling agent to penetrate into the fiber interior of the fabric and adhere to the surface. When heated and cured, the silanol groups between the hydrolyzed silane coupling agents can undergo condensation polymerization, thereby forming a layer of silane condensation product firmly anchored on the fabric. At the same time, the amino groups on the silane coupling agents containing amino groups serve as newly introduced active sites, laying the foundation for the chemical bonding of subsequent flame retardant additives. Furthermore, the flame retardant additives of the present invention have aldehyde groups, which can undergo Schiff base reactions with the amino groups introduced on the fabric to form stable chemical bonds, thereby ensuring that the additives are firmly and uniformly loaded on the fabric.

[0050] Another technical solution provided by the present invention: a modified fabric prepared by the above-described method for preparing modified fabric.

[0051] In some embodiments of the present invention, the loading of the bio-based flame retardant on the modified fabric is 5%-12%.

[0052] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: Addressing the shortcomings of existing flame-retardant additives, which often fail to simultaneously achieve flame retardancy, hydrophobicity, flexibility, and especially durability, and are subject to complex preparation processes, the inventors of this invention, during extensive experimental research, unexpectedly discovered that by using a main-chain polyphosphazene structure as the primary flame-retardant matrix and simultaneously introducing two specific bio-based monomers onto the side chains, a novel approach can be achieved. One of the bio-based monomers is an aromatic compound with aldehyde and hydroxyl groups. The presence of the aldehyde group reserves active sites, allowing for subsequent chemical bonding with active groups such as amino groups on the fabric surface. This significantly enhances the adhesion between the additive and the fabric, solving the technical problems of easy detachment and poor functional durability of existing finishing agents. Simultaneously, the aromatic ring and the main-chain polyphosphazene... The structure achieves a synergistic flame-retardant effect, promoting the formation of a dense char layer during combustion and effectively blocking heat and oxygen transfer, thereby significantly improving flame-retardant performance. On the other hand, one of the bio-based monomers is a compound with hydroxyl groups and aliphatic segments with 5 or more carbon atoms. Its long-chain structure can form a hydrophobic layer on the fabric surface, giving the fabric good hydrophobic properties, effectively resisting water stains and dirt, reducing the weight increase, decreased breathability and aging problems caused by water absorption, and significantly improving the user experience and service life. At the same time, the long-chain structure has a plasticizing effect, which can improve the flexibility of the fabric after the additives are cured, avoid the problem of fabric stiffness, and ensure wearing comfort and performance. In particular, by adjusting the ratio between two specific bio-based monomers, the synergistic optimization of flame retardancy, hydrophobicity, and flexibility is achieved. At the same time, the preparation and application methods of this invention are simple and easy to implement, the reaction conditions are mild, no special equipment is required, it is suitable for industrial production, and has broad market application prospects. Attached Figure Description

[0053] Figure 1 This is a scanning electron microscope (SEM) image of the original polyester fiber fabric of blank control 1 of the present invention; Figure 2 This is a scanning electron microscope (SEM) image of the modified fabric of Example 1 of the present invention; Figure 3 Digital photograph of the vertical combustion performance test of the original polyester fiber fabric used as blank control 1 of this invention; Figure 4 This is a digital photograph of the vertical combustion performance test of the modified fabric in Example 1 of the present invention. Figure 5 This is a graph showing the water contact angle test results of the polyester fiber raw fabric of blank control 1 of the present invention; Figure 6 This is a graph showing the water contact angle test results of the modified fabric in Example 1 of the present invention. Detailed Implementation

[0054] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0055] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0056] Cashew phenol (industrial grade, 87%-90%) was purchased from Cardlä Company (Zhuhai, China): a pale yellow liquid composed of 41 wt.% triene, 36 wt.% diene, 20 wt.% monoene and 3 wt.% saturated compound.

[0057] Example 1: This example provides a bio-based flame retardant additive, a modified fabric, and a method for preparing them. The specific preparation process is as follows: (1) Synthesis of a substance with the structure shown in formula (Ⅰ) (linear polydichlorophosphazene): 10 g of hexachlorocyclotriphosphazene was added to 10 mL of 1,2,4-trichlorobenzene, and 0.12 g of catalyst (composed of aminosulfonic acid and calcium sulfate dihydrate in a mass ratio of 1:0.11) was added. The mixture was stirred at 208 °C for 4 h under nitrogen protection. After the reaction was completed, the mixture was cooled slightly, and the reaction solution was poured into excess petroleum ether and washed three times until the upper liquid was colorless and transparent. 6.2 g of light brown elastomer was collected and dissolved in anhydrous tetrahydrofuran to form an anhydrous tetrahydrofuran solution of linear polydichlorophosphazene, which was then sealed and stored for later use. GPC (gel permeation chromatography) determined that the weight-average molecular weight of the prepared linear polydichlorophosphazene was 13600 and the polydispersity index was 1.16.

[0058] The reaction process is roughly as follows: .

[0059] (2) Bio-based substitution reaction: ① Preparation of nucleophilic reagents: Under ice bath conditions and nitrogen protection, 4.88 g of vanillin was slowly added dropwise to an anhydrous tetrahydrofuran solution containing 0.49 g of sodium metal wire, and 38.74 g of cashew phenol was slowly added dropwise to an anhydrous tetrahydrofuran solution containing 1.97 g of sodium metal wire. After each addition was completed, the temperature was raised to 66 °C and the reaction continued until the sodium metal wire completely disappeared, thus preparing vanillin sodium phenolate reagent and cashew phenolate sodium phenolate reagent, respectively. The next step is to use the mixture of the reagents obtained after the reaction directly. The reaction process is roughly as follows: ; ; ② Nucleophilic substitution reaction: Under ice bath conditions and nitrogen protection, the anhydrous tetrahydrofuran solution of linear polydichlorophosphazene prepared in step (1) was slowly added dropwise to the sodium vanillin phenolate reagent. After the addition was completed, the sodium cashew phenolate reagent was added dropwise. After all the addition was completed, the temperature was raised to 66℃ and the reaction was carried out for 60h. After the reaction was completed, most of the solvent was removed by rotary evaporation. The product was repeatedly precipitated and purified three times in excess petroleum ether and water. It was then vacuum dried at 60℃ overnight to obtain a viscous bio-based flame retardant. The reaction process is roughly as follows: ; In the structural formula of bio-based flame retardant additives, x corresponds to the functional group. Group corresponding to y The chlorine on the linear polydichlorophosphazene is randomly substituted, and simultaneous substitution may occur on the same phosphorus group. and It is also possible that both are or The repeating units they form are arranged linearly and randomly in any order, while simultaneously satisfying x∶y=2∶8.

[0060] (3) Fabric pretreatment: The polyester fiber fabric is immersed in a silane coupling agent KH550 solution (KH550 is dispersed in a solvent to prepare a 1% mass fraction solution, and the solvent is ethanol and water in a volume ratio of 1:1). After immersion for 30 min, it is cured at 130℃ for 8 min to obtain a polyester fiber fabric with amino on the surface (fabric intermediate).

[0061] (4) The fabric intermediate was immersed in a dispersion of bio-based flame retardant (the dispersion was obtained by dispersing the bio-based flame retardant in a composite solvent, the mass fraction of the bio-based flame retardant in the dispersion was 10%, the composite solvent was tetrahydrofuran / ethanol / water, and the volume ratio of tetrahydrofuran, ethanol and water was 3:1:1), soaked for 45 min, taken out and pre-dried at 90°C for 2.5 min, and then cured at 140°C for 6 min to obtain functionalized polyester fiber fabric (i.e. the modified fabric of the present invention). The loading of bio-based flame retardant on the modified fabric was measured to be 8% by the weight gain test.

[0062] Example 2: This example provides a bio-based flame retardant additive, a modified fabric, and a method for preparing them. The specific preparation process is as follows: (1) Synthesis of a substance with the structure shown in formula (Ⅰ) (linear polydichlorophosphazene): 10 g of hexachlorocyclotriphosphazene was added to 9 mL of 1,2,4-trichlorobenzene, and 0.11 g of catalyst (composed of aminosulfonic acid and calcium sulfate dihydrate in a mass ratio of 1:0.11) was added. The reaction was stirred at 210 °C for 5 h under nitrogen protection. After the reaction was completed, the mixture was cooled slightly and the reaction solution was poured into excess petroleum ether and washed 3 times until the upper liquid was colorless and transparent. 5.8 g of light brown elastomer was collected and dissolved in anhydrous tetrahydrofuran to form an anhydrous tetrahydrofuran solution of linear polydichlorophosphazene, which was then sealed and stored for later use.

[0063] (2) Bio-based substitution reaction: ① Preparation of nucleophilic reagents: Under ice bath conditions and nitrogen protection, 7.33 g of p-hydroxybenzaldehyde was slowly added dropwise to an anhydrous tetrahydrofuran solution containing 0.92 g of sodium metal wire, and 28.16 g of methyl ricinoleate was slowly added dropwise to an anhydrous tetrahydrofuran solution containing 1.38 g of sodium metal wire. After each addition was completed, the temperature was raised to 68 °C and the reaction continued until the sodium metal wire completely disappeared, thus preparing sodium p-hydroxybenzaldehyde phenolate reagent and sodium methyl ricinoleate ol reagent, respectively. The next step is to use the mixture of the reagents obtained after the reaction directly. ; ; ② Nucleophilic substitution reaction: Under ice bath conditions and nitrogen protection, the anhydrous tetrahydrofuran solution of linear polydichlorophosphazene prepared in step (1) was slowly added dropwise to sodium p-hydroxybenzaldehyde phenolate reagent. After the addition was completed, sodium methyl ricinoleate reagent was added dropwise. After all the addition was completed, the temperature was raised to 68℃ and the reaction was carried out for 55 hours. After the reaction was completed, most of the solvent was removed by rotary evaporation. The product was repeatedly precipitated and purified three times in excess petroleum ether and water. It was then vacuum dried overnight at 70℃ to obtain a viscous bio-based flame retardant. The synthesis process is shown below, where x∶y=4∶6. .

[0064] (3) Fabric pretreatment: The hemp fiber fabric is immersed in KH792 solution (KH792 is dispersed in the solvent to prepare a solution with a mass fraction of 1.5%, and the solvent is composed of ethanol and water in a volume ratio of 1:1). After immersion for 35 minutes, it is cured at 140℃ for 7 minutes to obtain modified hemp fiber fabric with amino on the surface (fabric intermediate).

[0065] (4) The fabric intermediate was immersed in a dispersion of bio-based flame retardant (the dispersion was obtained by dispersing the bio-based flame retardant in a composite solvent, the mass fraction of the bio-based flame retardant in the dispersion was 12%, the composite solvent was chloroform / ethanol / water, and the volume ratio of chloroform, ethanol and water was 3:1:1), soaked for 50 min, taken out and pre-dried at 95°C for 2.5 min, and then cured at 145°C for 6 min to obtain functionalized hemp fiber fabric (i.e. the modified fabric of the present invention). The loading of bio-based flame retardant on the modified fabric was measured to be 10% by the weight gain test.

[0066] Example 3: This example provides a bio-based flame retardant additive, a modified fabric, and a method for preparing them. The specific preparation process is as follows: (1) Synthesis of a substance with the structure shown in formula (Ⅰ) (linear polydichlorophosphazene): 10 g of hexachlorocyclotriphosphazene was added to 12 mL of 1,3,5-trichlorobenzene, and 0.15 g of catalyst (composed of aminosulfonic acid and calcium sulfate dihydrate in a mass ratio of 1:0.12) was added. The mixture was stirred at 205 °C for 6 h under nitrogen protection. After the reaction was completed, the mixture was cooled slightly and the reaction solution was poured into excess petroleum ether and washed 3 times until the upper liquid was colorless and transparent. 5.0 g of light brown elastomer was collected and dissolved in anhydrous acetonitrile to form an anhydrous acetonitrile solution of linear polydichlorophosphazene, which was then sealed and stored for later use.

[0067] (2) Bio-based substitution reaction: ① Preparation of nucleophilic reagents: Under ice bath conditions and nitrogen protection, 11.85 g of eugenol was slowly added dropwise to an anhydrous acetonitrile solution containing 0.99 g of sodium metal wire, and 19.43 g of oleyl alcohol was slowly added dropwise to an anhydrous acetonitrile solution containing 0.99 g of sodium metal wire. After each addition was completed, the temperature was raised to 68 °C and the reaction continued until the sodium metal wire completely disappeared, thus preparing sodium eugenol phenolate reagent and sodium oleyl alcohol reagent, respectively. The next step is to use the mixture of the reagents obtained after the reaction directly. The reaction process is roughly as follows: ; ; ② Nucleophilic substitution reaction: Under ice bath conditions and nitrogen protection, the anhydrous acetonitrile solution of linear polydichlorophosphazene prepared in step (1) was slowly added dropwise to sodium eugenol phenolate reagent. After the addition was completed, sodium ethanol alkoxide reagent was added dropwise. After all the addition was completed, the temperature was raised to 80℃ and the reaction was carried out for 72 hours. After the reaction was completed, most of the solvent was removed by rotary evaporation. The product was repeatedly precipitated and purified three times in excess petroleum ether and water. It was then vacuum dried overnight at 60℃ to obtain a viscous bio-based flame retardant. The synthesis process is shown below, x∶y=5∶5. The reaction process is roughly as follows: ; (3) Fabric pretreatment: The polyester-cotton blended fiber fabric is immersed in KH550 solution (KH550 is dispersed in solvent to prepare a solution with a mass fraction of 0.5%, and the solvent is ethanol and water in a volume ratio of 1:1). After immersion for 40 min, it is cured at 120℃ for 8 min to obtain modified blended fabric with amino on the surface (fabric intermediate).

[0068] (4) The fabric intermediate is immersed in a dispersion of bio-based flame retardant (the dispersion is obtained by dispersing the bio-based flame retardant in a composite solvent, the mass fraction of the bio-based flame retardant in the dispersion is 5%, the composite solvent is dichloromethane / ethanol / water, and the volume ratio of dichloromethane, ethanol and water is 3:1:1), soaked for 60 min, taken out and pre-dried at 80℃ for 3 min, and then cured at 130℃ for 8 min to obtain the functionalized blended fabric (i.e. the modified fabric of the present invention). The loading of the bio-based flame retardant on the modified fabric is 5% by the weight gain test.

[0069] Comparative Example 1: The process is basically the same as in Example 1, except that only 48.4g of cashew phenol is added in the bio-based substitution reaction, the amount of sodium metal is adjusted to 2.47g, and vanillin is not added. That is, the molar ratio of the first monomer to the second monomer is 0:10 (the total molar amount of the first monomer and the second monomer remains unchanged).

[0070] Comparative Example 2: The process is basically the same as in Example 1, except that in the bio-based substitution reaction, the amount of vanillin is adjusted to 17.08g (the amount of sodium metal is adjusted to 1.72g accordingly), and the amount of cashew phenol is adjusted to 14.53g (the amount of sodium metal is adjusted to 0.73g accordingly), that is, the molar ratio of the first monomer to the second monomer is 7:3.

[0071] Comparative Example 3: The process is basically the same as in Example 1, except that the fabric was not modified with KH550 and proceeded directly to step (4).

[0072] Performance testing: The modified fabrics prepared in Examples 1-3 and Comparative Examples 1-3, as well as the original fabrics (blank control group) without soaking in bio-based flame retardant additives corresponding to each example, were subjected to performance tests. The test items included limiting oxygen index (LOI, to evaluate flame retardant performance), vertical burning performance (to evaluate flame retardant performance), water contact angle (WCA, to evaluate hydrophobicity), hand feel (to evaluate flexibility), and number of washes (to evaluate adhesion and functional durability). The test standards are as follows: Limiting Oxygen Index is tested according to GB / T 5454-1997; vertical combustion performance is tested according to GB / T 5455-2014; water contact angle is tested according to GB / T 42694-2023; hand feel adopts the subjective scoring method (5 points: soft, 4 points: relatively soft, 3 points: moderate, 2 points: relatively hard, 1 point: stiff); washing resistance cycles are tested according to GB / T 8629-2017 (Procedure 5A), and it is qualified if LOI≥25% and WCA≥95% are still satisfied after washing. The above test results are shown in Table 1.

[0073] Table 1

[0074] It can be seen from Table 1: ① The Limiting Oxygen Index (LOI) of the blank control fabric is only 18.0%~21.0% (which belongs to flammable material), and the vertical combustion performance is characterized by easy ignition, fast burning speed or accompanied by molten droplets, with no self-extinguishing ability; the LOI of the functionalized fabrics of Examples 1 to 3 are all ≥31.5%, which is significantly improved compared with the blank group, all of which can rapidly self-extinguish within 2 to 5 seconds in the vertical combustion test, without flame spread and molten droplet phenomena, and the damaged length is 4.2 to 5.7 cm. Analysis suggests that this is because the aromatic ring of the first monomer, namely the aldehyde group-containing monomer, forms a synergistic flame retardant effect with the phosphorus and nitrogen elements in the polyphosphazene main chain, which can promote the formation of a dense carbon layer during the combustion process, effectively block the transfer of heat and oxygen, thereby significantly improving the flame retardant performance; in Comparative Example 1, since the first monomer, namely the aldehyde group-containing bio-based monomer, is not added, and the flame retardant effect only relies on the second monomer, namely the phenol / hydroxyl aliphatic chain monomer, and the polyphosphazene main chain, the flame retardant effect is reduced; while in Comparative Example 2, the proportion of the first monomer, namely the aldehyde group-containing monomer, is high, and the aromatic ring of the aldehyde group-containing monomer can form a synergistic effect with the phosphorus-nitrogen main chain, so the flame retardant effect is good, but other properties such as durability and hydrophobicity are insufficient; the flame retardancy of Comparative Example 3 is basically similar to that of Comparative Example 1, which is relatively weak, because Comparative Example 3 does not use KH550 to pretreat the fabric, there is only physical adsorption between the flame retardant auxiliary and the fibers, and there is a lack of stable chemical bonding and interfacial interaction. The auxiliary is easy to migrate and run off during the combustion process, and it is difficult to form a continuous and dense carbon layer, so the flame retardant performance is weak. In Comparative Example 1, only a single component of cardanol is used to substitute the phosphazene, which lacks the rigid aromatic ring and multi-functional group structure provided by the first monomer, resulting in low carbon formation efficiency and thermal stability, as well as insufficient interfacial bonding force with the fibers.

[0075] Figure 1 is the SEM image of the original fabric of Blank Control 1, showing that the fiber surface of the original fabric is smooth without attachments; Figure 2 is the SEM image of the modified fabric of Example 1, showing that the flame retardant auxiliary of the present invention is uniformly deposited on the fiber surface to form a dense coating without obvious pore defects.

[0076] Figure 3The image shows a burning test of the original fabric used as blank control 1. It can be seen that the fabric burns violently and is accompanied by melting and dripping, and has no self-extinguishing ability. Figure 4 The image shows a combustion test photo of the modified fabric from Example 1. It can be seen that the fabric self-extinguishes rapidly after the flame source is removed, with no flame spread or dripping.

[0077] ② The water contact angle of the blank control group was 0°, indicating a completely hydrophilic state, where water droplets could quickly wet the fabric. However, after adding the bio-based flame retardant additive of this invention, the WCA of the samples was ≥108.0°, meeting the hydrophobic performance requirements (WCA≥105°). Analysis suggests this is because the fatty chains of the second monomer, namely phenol / hydroxy aliphatic chain bio-based monomers, such as long-chain alkyl groups, form a dense hydrophobic layer on the fabric surface, hindering the contact between water molecules and the fabric surface. Comparative Example 1, containing only cashew phenol, has a complete hydrophobic layer and possesses a certain degree of hydrophobicity, but it is still lower than Example 1. This is because although Comparative Example 1 contains hydrophobic cashew phenol segments, its low bonding strength with the fiber results in poor continuity and stability of the surface hydrophobic layer, leading to a lower water contact angle than Example 1. In Example 1, vanillin, the first monomer, enhances the polar interaction and bonding ability between the flame retardant additive and the aminated fabric, allowing the hydrophobic cashew phenol segments to be stably and uniformly distributed on the fiber surface, thereby achieving higher hydrophobicity. In Comparative Example 2, the proportion of the first monomer, i.e., the aldehyde monomer, was too high, and the amount of cashew phenol was reduced. The hydrophobic layer formed by the long-chain alkyl group was incomplete. Although it was still in a weakly hydrophobic state, it no longer met the requirements for high hydrophobic performance. In Comparative Example 3, the fabric was not pretreated with KH550. The bio-based flame retardant additive lacked a stable interaction with the fiber. The continuity and stability of the surface hydrophobic layer were poor, and the water contact angle was low, lower than that of Example 1.

[0078] Figure 5 The water contact angle diagram of the original fabric in blank control 1 shows that water droplets quickly wet the fabric with a water contact angle of 0° (completely hydrophilic). Figure 6 The diagram shows the water contact angle of the modified fabric in Example 1, indicating that water droplets are stably present on the fabric surface, with a water contact angle of 120.3° (hydrophobic).

[0079] ③ The blank control group all scored 5 points (soft) in terms of feel, while Examples 1-3 scored 3-4 points, maintaining good flexibility without stiffness. Analysis suggests this is due to the controlled ratio of the first to the second monomer, particularly the plasticizing effect of the long-chain phenol / hydroxy aliphatic bio-based monomer in the second monomer, which effectively alleviates the rigidity caused by the polyphosphazene backbone and the aromatic ring of the aldehyde monomer. In Comparative Example 2, due to an excess of the second monomer (aldehyde monomer) and insufficient long-chain alkyl content, the plasticizing effect was weakened, highlighting the rigidity of the polyphosphazene backbone and aromatic ring, resulting in a feel score of only 2 points (relatively hard) and a significant decrease in comfort.

[0080] ④ Examples 1-3 all had a wash resistance of ≥25 times, far exceeding Comparative Example 1 (6 times), Comparative Example 2 (15 times), and Comparative Example 3 (5 times). Analysis suggests this is because the present invention introduces amino groups into the fabric surface through silane coupling agent pretreatment. The aldehyde groups in the flame retardant can react with the amino groups to form stable chemical bonds, significantly improving the adhesion between the additive and the fabric. Comparative Example 1 lacked aldehyde monomers, and the additive only bonded to the fabric through physical adsorption, resulting in weak adhesion. Although Comparative Example 2 contained aldehyde monomers that could form Schiff base reactions, the high proportion of aldehyde groups increased the rigidity of the molecular structure, leading to decreased chemical bond stability. Furthermore, the incomplete hydrophobic layer made the additive susceptible to erosion during washing, thus its wash resistance was still far lower than Example 1, failing to meet long-term use requirements. Comparative Example 3 did not pretreat the fabric, lacking amino sites to form chemical bonds with the additive, making the additive prone to detachment, resulting in extremely poor functional durability.

[0081] In summary, this invention provides a bio-based flame retardant additive and its application, solving the technical problems of existing fabric finishing agents, such as complex coating structures, cumbersome preparation processes, poor adhesion, insufficient functional durability, difficulty in simultaneously achieving flame retardancy and hydrophobicity, and poor flexibility. Through specific raw material screening, formulation optimization, and preparation and application process design, an environmentally friendly and renewable bio-based flame retardant additive and functionalized modified fabrics with excellent flame retardancy, good hydrophobicity, good flexibility, strong adhesion to fabrics, and excellent washability are obtained, thus broadening the application prospects of bio-based flame retardant additives in clothing, home furnishings, fire protection, and other fields.

[0082] As used throughout the specification and claims, the term "comprising" is an open-ended term and should be interpreted as "comprising but not limited to." "Substantially" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect. It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the product or system comprising said element.

[0083] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0084] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A bio-based flame retardant additive, characterized in that, The flame retardant additive comprises materials made by a substitution reaction between a substance having the structure shown in Formula (I) and a bio-based monomer; In equation (Ⅰ), n is greater than or equal to 10; The bio-based monomer comprises a first monomer and a second monomer. The first monomer is selected from one, two, or more of the following: vanillin or its derivatives; eugenol or its derivatives; p-hydroxybenzaldehyde or its derivatives; sinigral or its derivatives; salicylaldehyde or its derivatives; 5-hydroxymethylfurfural or its derivatives. The second monomer is selected from one, two, or more of the following: cashew nut shell extract; oleyl alcohol; ricinoleic acid; methyl ricinoleate; lauryl alcohol; stearyl alcohol; palmitol. Based on a total molar amount of 100 mol% for the first monomer and the second monomer, the first monomer accounts for 15 mol%-65 mol%, and the second monomer accounts for 35 mol%-85 mol%. During the substitution reaction, the bio-based monomer is added in the form of a metal salt.

2. The bio-based flame retardant additive according to claim 1, characterized in that, With the total molar amount of the first monomer and the second monomer being 100 mol%, the bio-based monomers contain the first monomer at 15 mol%-50 mol% and the second monomer at 50 mol%-85 mol%; and / or, n is 10-5000.

3. The bio-based flame retardant additive according to claim 1, characterized in that, With the total molar amount of the first monomer and the second monomer being 100 mol%, the bio-based monomer comprises 17 mol%-40 mol% of the first monomer and 60 mol%-83 mol% of the second monomer; and / or, n is 20-2500.

4. The bio-based flame retardant additive according to claim 1, characterized in that, The metal salt is a sodium salt of a bio-based monomer, which is prepared by the following method: under the protection of a protective gas, the first monomer or the second monomer is added to an aqueous solution of metallic sodium, and the mixture is heated to react; wherein the molar amount of the first monomer or the second monomer added is in excess of the metallic sodium.

5. The bio-based flame retardant additive according to claim 1, characterized in that, The substance having the structure shown in formula (I) is prepared by the following method: in the presence of a catalyst and under the protection of a protective gas, hexachlorocyclotriphosphazene is reacted under heating conditions to generate the substance having the structure shown in formula (I); The catalyst is composed of aminosulfonic acid and calcium sulfate or its hydrate in a mass ratio of 1:0.1-0.12, and the reaction is controlled at 190-215°C. The mass ratio of hexachlorocyclotriphosphazene to the catalyst is 1:0.01-0.

015.

6. The bio-based flame retardant additive according to claim 1, characterized in that, The substitution reaction is controlled to be carried out at a temperature of 65-90°C; and / or, the flame retardant is prepared by the following method: the substance having the structure shown in formula (I) is added to the metal salt corresponding to the first monomer, and after the addition is complete, the metal salt corresponding to the second monomer is added to the reaction system, and after all the addition is complete, the temperature is raised to react.

7. A bio-based flame retardant additive, characterized in that, The flame retardant additive has the structure shown in formula (Ⅲ); ； In equation (Ⅲ), n1, n2, and n3 are each independently greater than or equal to 0, and the sum of n1, n2, and n3 is greater than or equal to 10; and in the repeating units corresponding to n1, n2, and n3, when the total molar amount of R4 and the total molar amount of R5 are 100 mol%, R4 accounts for 15 mol%-65 mol%, and R5 accounts for 35 mol%-85 mol%; the repeating units corresponding to n1, n2, and n3 are arranged linearly in any order; R4 is the residual group after removing one hydroxyl group from the first monomer, and R5 is the residual group after removing one hydroxyl group from the second monomer. The first monomer is selected from one, two or more of vanillin or its derivatives, eugenol or its derivatives, p-hydroxybenzaldehyde or its derivatives, sinigral or its derivatives, salicylaldehyde or its derivatives, 5-hydroxymethylfurfural or its derivatives; the second monomer is selected from one, two or more of cashew phenol, oleyl alcohol, ricinoleic acid, methyl ricinoleate, lauryl alcohol, stearyl alcohol, palmitol.

8. The use of a bio-based flame retardant additive as described in any one of claims 1-7 in the preparation of modified fibers or modified fabrics.

9. A method for preparing a modified fabric, characterized in that, The preparation method includes: (1) Immerse the fabric in a silane coupling agent solution, separate it after immersion, heat and solidify it to make a fabric intermediate; The silane coupling agent solution is prepared by dispersing an amino-containing silane coupling agent in a solvent. (2) The fabric intermediate is immersed in the dispersion of the bio-based flame retardant additive according to any one of claims 1-7. After immersion, it is separated and heated to solidify, thus producing the modified fabric.

10. The method for preparing the modified fabric according to claim 9, characterized in that, In step (1), the amino-containing silane coupling agent comprises N-(β-aminoethyl)-γ-aminopropyltriethoxysilane and / or γ-aminopropyltriethoxysilane; And / or, in step (1), the solvent used in the silane coupling agent solution includes ethanol and water, and the volume ratio of ethanol to water is 1:0.8-1.2; And / or, in step (1), the silane coupling agent solution contains 0.5%-2.0% by mass of an amino-containing silane coupling agent; And / or, in step (1), the heating and curing process is controlled to be carried out at 120-150°C.

11. The method for preparing the modified fabric according to claim 9, characterized in that, In step (2), the heating and curing process is controlled to be carried out at 130-150℃; And / or, in step (2), the dispersion of the bio-based flame retardant is obtained by dispersing the bio-based flame retardant in a composite solvent, wherein the composite solvent is composed of a first organic solvent, a second organic solvent and water, and the volume ratio of the first organic solvent, the second organic solvent and the water is 2-4:0.8-1.2:1, wherein the first organic solvent is at least one selected from tetrahydrofuran, acetonitrile, dichloromethane and trichloromethane, and the second organic solvent is an alcohol solvent; And / or, in step (2), the bio-based flame retardant additive dispersion contains 5%-15% by mass of the bio-based flame retardant additive; And / or, the process of step (2) is as follows: the fabric intermediate is immersed in the dispersion of the bio-based flame retardant additive according to any one of claims 1-10, and after immersion, it is taken out and pre-dried at 80-100°C, and then cured at 130-150°C.

12. A modified fabric prepared by the method of preparing the modified fabric according to any one of claims 9-11.

13. The modified fabric according to claim 12, characterized in that, The loading of the bio-based flame retardant on the modified fabric is 5%-12%.

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