Leather base cloth with flame retardant property and preparation method thereof

Abstract

The invention discloses leather base cloth with flame retardance and a preparation method thereof.The leather base cloth comprises a surface layer and a coating layer, the surface layer is PET non-woven cloth, and the coating layer is prepared from, by mass, 30-50 parts of polyurethane, 6-15 parts of phosphorus flame retardant, 0.1-1 part of nano-silver antibacterial agent, 5-10 parts of acetylated glyceride, 4-8 parts of cross-linking agent and 1-3 parts of dispersing agent; the phosphorus flame retardant is at least one of triphenyl phosphate, resorcinol bis (diphenyl phosphate) and bisphenol A bis (diphenyl phosphate), so that the prepared leather base cloth has good flame retardance and flexibility.

Description

Technical Field

[0001] The present application relates to the field of leather base fabric synthesis, and in particular to a leather base fabric with flame retardant properties and a preparation method thereof. Background Art

[0002] Leather fabric is the core skeleton layer of artificial leather, providing mechanical support and structural stability. Its technological development stems from the demand for alternatives to the limited supply, high cost and environmental ethics of natural leather, as well as modern consumers' higher expectations for material diversity, functionality and environmental friendliness. With technological advancements, fabrics have gradually expanded from early non-woven fabrics to woven structures (woven, knitted) and non-woven reinforced composite structures, with the core goal of improving the physical strength, dimensional stability, processing adaptability and appearance simulation of artificial leather. The key is that modern high-performance leather fabrics have become a platform carrier that integrates lightweight, environmental protection and multi-functionality.

[0003] The current core development advantages of leather fabrics are significant: first, improved sustainability, with the widespread use of recycled polyester or bio-based fibers; second, strong functional integration capabilities, particularly in achieving high-efficiency flame retardancy. Through fiber modification, finishing, or coating technologies, these fabrics meet self-extinguishing standards upon removal from flame, thus meeting mandatory safety regulations for automotive interiors, public transportation, and specific protective applications. However, balancing flame retardancy with a soft feel remains a significant challenge: achieving high flame retardancy often requires a high proportion of flame retardant additives or a rigid structure, which can easily lead to insufficient base fabric softness. Summary of the Invention

[0004] In order to solve the problem of insufficient softness of traditional flame-retardant leather base fabrics, a flame-retardant leather base fabric and a preparation method thereof are provided.

[0005] The above-mentioned object of the present invention is achieved through the following technical solutions: A flame-retardant leather base fabric comprises a surface layer and a coating layer, wherein the surface layer is a PET non-woven fabric, and the coating layer comprises the following components in parts by weight: 30-50 parts of polyurethane, 6-15 parts of phosphorus flame retardant, 0.1-1 part of nano silver antibacterial agent, 5-10 parts of acetylated glyceride, 4-8 parts of crosslinking agent, and 1-3 parts of dispersant, wherein the phosphorus flame retardant is at least one of triphenyl phosphate, resorcinol bis(diphenyl phosphate), and bisphenol A bis(diphenyl phosphate).

[0006] Through the above technical solution, phosphorus-based flame retardants decompose to produce phosphoric acid or polyphosphoric acid when heated, which promotes the dehydration and carbonization of the polymer to form an expanded carbon layer, isolating oxygen and heat. Triphenyl phosphate first decomposes to produce phosphoric acid in the low temperature zone, catalyzing the dehydration of the polymer to form an initial carbon layer; polyphosphoric acid produced by the decomposition of resorcinol bis(diphenyl phosphate) in the medium temperature zone further cross-links the carbon layer to fill the pores; bisphenol A bis(diphenyl phosphate) releases gas at high temperature, causing the carbon layer to expand and thicken, achieving full temperature range protection of "low temperature carbonization-medium temperature reinforcement-high temperature expansion"; nanosilver antibacterial agent releases Ag + It destroys microbial cell membranes and enzymes, providing long-lasting antibacterial properties. Acetylated glycerides contain both lipophilic fatty acid ester groups and hydrophilic hydroxyl / acetoxy groups, which are inserted between PU polymer segments to weaken the interaction between the segments. The molecular segments are easier to move, curl and slip, thereby improving the softness of the material. At the same time, the ester groups of acetylated glycerides and the phosphate groups in the phosphorus-based flame retardants form a weak cross-linked network through hydrogen bonds or dipole-dipole interactions, reducing the migration of small molecules of the flame retardant to the surface of the base fabric and prolonging the durability of the flame retardant effect.

[0007] Optionally, the coating layer further comprises 0.5 to 2 parts of polyether-modified silicone.

[0008] Through the above technical solution, the molecular structure of polyether-modified silicone makes it tend to migrate and accumulate on the surface of the coating layer and the air / solid interface. The surface-enriched polyether-modified silicone effectively reduces the friction coefficient of the base fabric surface and improves the surface softness.

[0009] Optionally, the polyether-modified siloxane is prepared by the following process: Raw material pretreatment: adding hydrogen-containing siloxane to a reactor, evacuating the reactor and then introducing nitrogen to dehydrate the reactor to obtain dehydrated hydrogen-containing siloxane; dehydrating the allyl polyether to obtain dehydrated allyl polyether; Mixed catalysis: Dehydrated hydrogenated siloxane, dehydrated allyl polyether and solvent are stirred and mixed to obtain a mixed solution, platinum catalyst diluted with organic alcohol is added dropwise to the mixed solution at a constant rate, and the mixture is heated to 90°C and allowed to react to obtain a reaction solution; Post-treatment: After the reaction solution is cooled, activated carbon is added and stirred, filtered, and the solvent is removed in vacuo to obtain an organic phase, which is washed and dehydrated to obtain polyether-modified siloxane.

[0010] Through the above technical solution, dehydration treatment prevents the water in hydrogenated silicone oil and allyl polyether from poisoning and deactivating the platinum catalyst; platinum-catalyzed hydrogenation allows the hydrogenated silicone oil and allyl polyether to efficiently undergo hydrosilylation reaction; residual catalyst is removed to avoid the negative impact of catalyst residue on subsequent processing or the stability of the PU system; high-quality polyether-modified siloxane can more stably and effectively exert its surface slipperiness and friction-reducing effects, thereby enhancing the soft feel of the surface of the base fabric.

[0011] Optionally, the hydrogen-containing siloxane in the preparation process of the polyether-modified siloxane is pentamethyldisiloxane.

[0012] Through the above technical solution, after the low molecular weight pentamethyldisiloxane reacts with allyl polyether, the modified siloxane obtained has a clear molecular structure and a small molecular weight. The product with a small molecular weight has better mobility and can be enriched on the surface of the PU coating more quickly and fully to effectively play the role of reducing the friction coefficient, thereby improving the surface smoothness and soft feel of the base fabric.

[0013] Optionally, the organic alcohol in the preparation process of polyether-modified siloxane is isopropyl alcohol.

[0014] Through the above technical solution, isopropyl alcohol effectively dissolves and dilutes the platinum catalyst, ensuring that it can be added dropwise to the reaction system in a stable and uniform manner, effectively exerting the role of the platinum catalyst.

[0015] Optionally, the acetylated glyceride is glyceryl monoacetate.

[0016] Through the above technical solution, the molecular polarity of monoacetin is moderate, the compatibility with the polyurethane system is better, and it is not easy to migrate and precipitate. The retained hydroxyl groups can participate in the hydrogen bonding in the polyurethane system and anchor on the polyurethane molecular chain, thereby improving the softness of the body and not easy to seep out. The single acetyl group has small steric hindrance and has less hindrance when inserted between polyurethane chain segments. Its stronger binding force (and excellent compatibility) make it possible to better improve the overall softness and flexibility of the base fabric at the same dosage. The two free hydroxyl groups undergo a dehydration reaction at the initial stage of combustion, thereby improving the flame retardant effect.

[0017] Optionally, the cross-linking agent is a trifunctional aziridine cross-linking agent.

[0018] Through the above technical solution, the trifunctional aziridine has three highly active aziridine groups, and its spatial configuration determines that it has certain spatial limitations when forming a cross-linked network. Under the premise of ensuring the required strength of the base fabric, the trifunctional nitrogen forms a cross-linked network that is not overly rigid and still has certain chain segment activity, thereby avoiding the base fabric becoming brittle and hard due to excessive cross-linking.

[0019] The second object of the present invention is achieved by the following technical solutions: The method for preparing any one of the above-mentioned flame-retardant leather base fabrics comprises the following steps: Add polyurethane and dispersant into a reactor and stir, gradually add other raw materials of functional additives except polyurethane and dispersant, and continue stirring to obtain functional slurry; The PET nonwoven fabric is impregnated with the functional slurry to obtain a wet base fabric; After drying, curing and cooling, the leather base fabric is obtained.

[0020] Through the above technical solution, polyurethane and dispersant are added first to ensure that the functional additives are evenly and stably dispersed. Gradual addition helps prevent agglomeration, so that the various functional components are fully and evenly mixed with the polyurethane, preventing local softness deterioration or surface defects and decreased flame retardancy caused by uneven dispersion or agglomeration.

[0021] In summary, this application has at least the following beneficial effects: (1) Acetylated glycerol improves the overall softness and flexibility of the base fabric by weakening the interaction between polyurethane molecular chains; (2) Polyether-modified siloxane accumulates on the surface to form a low-friction layer, effectively reducing surface resistance and improving the smoothness and softness of the base fabric; (3) A trifunctional aziridine crosslinker is selected to construct a moderate network structure, which can avoid hardening caused by excessive crosslinking while ensuring the required strength and maintain the flexibility of the base fabric. DETAILED DESCRIPTION

[0022] raw material PET non-woven fabric, PET spunbond non-woven fabric, weight 60g / m 2 , purchased from Wenzhou Chaocheng Nonwoven Technology Co., Ltd.; polyurethane, water-based polyurethane, model AH-1704-1A, solid content 35±1wt%, specific gravity 1.06±0.02(g / cm 3 ), purchased from Anhui Anda Huatai New Materials Co., Ltd.; Triphenyl phosphate, purity ≥99.8 wt%, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Resorcinol bis(diphenyl phosphate), purity ≥98 wt%, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. Bisphenol A bis(diphenyl phosphate), purity ≥98 wt%, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Pentamethyldisiloxane, purity ≥95 wt%, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; 2,4,6,8-Tetramethylcyclotetrasiloxane (purity ≥ 98 wt%) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. Allyl polyether, allyl polyoxyethylene ether, molecular weight 2400, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Ethyl acetate, purity ≥99 wt%, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Platinum catalyst, KARSTEDT catalyst, mass concentration of 3000 ppm, purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.; Activated carbon, wood powder activated carbon, 200 mesh, moisture ≤ 10 wt%, ash ≤ 7 wt%, purchased from Qichong Activated Carbon (Ningxia) Co., Ltd. Isopropanol, purity ≥99.9 wt%, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. n-Propanol, purity ≥99.7 wt%, anhydrous grade, purchased from Shanghai Yuanye Biotechnology Co., Ltd.; Glyceryl monoacetate, purity ≥99 wt%, purchased from Hubei Qifei Pharmaceutical Chemical Co., Ltd.; Glyceryl triacetate, purity ≥97.5 wt%, was purchased from Nanjing Chemical Reagent Co., Ltd. Trifunctional aziridine crosslinker, solid content ≥98 wt%, purchased from Shanghai Hansi Chemical Co., Ltd. Carbodiimide, a water-based carbodiimide with a solid content of 40±2 wt%, was purchased from Guangdong Endes Chemical Co., Ltd.; dispersant, a sodium polyacrylate aqueous solution with a sodium polyacrylate content of 50 wt% and a Mw of 3000-5000, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. Anhydrous MgSO4 and NaCl were both commercially available.

[0023] Preparation Example 1 A polyether-modified siloxane, the preparation method of which is as follows: 1 kg of pentamethyldisiloxane was added to a reaction kettle, evacuated to -0.095 MPa, heated to 110±2°C, and bubbling with nitrogen at a flow rate of 5 L / min, and dehydrated to a moisture content of ≤50 ppm to obtain dehydrated pentamethyldisiloxane; Take 2kg of allyl polyoxyethylene ether and add it into the container. 200 g molecular sieves, stirred at 60 ° C for 2 h under nitrogen, and filtered to obtain dehydrated allyl polyoxyethylene ether; Dehydrated pentamethyldisiloxane, dehydrated allyl polyoxyethylene ether, and 3 kg of ethyl acetate were added in sequence, and the mixture was stirred at 200 rpm for 15 minutes to obtain a mixed solution. 5 g of Karstedt catalyst was diluted in 20 mL of isopropanol and then added to the mixed solution at a rate of 2 mL / min. The temperature was raised to 90 ± 1 °C at a rate of 2 °C / min, and the mixture was allowed to stand for 4 hours to obtain a reaction solution. After the reaction solution was cooled to 70°C, 24 g of wood powder activated carbon was added and stirred at 350 rpm for 30 min. The mixture was filtered using a funnel with a pore size of 10-15 μm. The filtrate was transferred to a rotary evaporator for desolvation until the residual solvent was ≤ 0.3 wt% to obtain an organic phase. The organic phase was washed with 4 L of 26.4 wt% NaCl solution, and 200 g of anhydrous MgSO4 was added, stirred for 30 min, and filtered to obtain polyether-modified siloxane.

[0024] Preparation Example 2 A polyether-modified siloxane is prepared in the following manner: the pentamethyldisiloxane and allyl polyoxyethylene ether are not dehydrated, and the pentamethyldisiloxane, allyl polyoxyethylene ether and ethyl acetate are directly mixed; the remaining components are the same as those in Preparation Example 1.

[0025] Preparation Example 3 A polyether-modified siloxane, which differs from Preparation Example 1 in that 2,4,6,8-tetramethylcyclotetrasiloxane of equal mass is used instead of pentamethyldisiloxane, and the rest is the same as Preparation Example 1.

[0026] Preparation Example 4 A polyether-modified siloxane is prepared in accordance with Preparation Example 1, wherein an equal volume of n-propanol is used instead of isopropanol, and the remaining parts are the same as those in Preparation Example 1.

[0027] Example 1 A flame-retardant leather base fabric is prepared from a surface layer and a coating layer, wherein the surface layer is a PET spunbond non-woven fabric, and the coating layer is composed of the following raw materials: 400 g of waterborne polyurethane, 30 g of triphenyl phosphate, 30 g of resorcinol bis(diphenyl phosphate), 30 g of bisphenol A bis(diphenyl phosphate), 5 g of a nano-silver antibacterial agent, 75 g of glycerol monoacetate, 60 g of trifunctional aziridine, 20 g of a sodium polyacrylate aqueous solution, and 12.5 g of a polyether-modified siloxane.

[0028] A flame-retardant leather base fabric, the preparation method of which is as follows: S1: Add waterborne polyurethane and sodium polyacrylate aqueous solution into a reactor and stir at 200 rpm for 10 min at 30°C; S2: Add triphenyl phosphate, resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), polyether-modified siloxane, monoacetin, and trifunctional aziridine in sequence while dispersing at 600 rpm. After the addition is complete, continue dispersing at 600 rpm for 20 min to obtain a functional slurry; S3: Use functional slurry to impregnate PET spunbond nonwoven fabric for 25s, 3kg / cm 2 Perform pressing, repeat the pressing twice to obtain a wet base fabric; S4: drying with hot air at 100° C. at a wind speed of 2.0 m / s for 10 min, and cooling to room temperature of 25° C. to obtain a leather base fabric.

[0029] Comparative Example 1 A flame-retardant leather base fabric is disclosed. The difference between the flame-retardant leather base fabric and Example 1 lies in that monoacetin is not added to the coating layer and the preparation method, and the rest of the flame-retardant leather base fabric is the same as Example 1.

[0030] Example 2 A flame-retardant leather base fabric, which differs from Example 1 in that triphenyl phosphate is not added to the coating layer and the preparation method, and the amount of resorcinol bis(diphenyl phosphate) is 45g and the amount of bisphenol A bis(diphenyl phosphate) is 45g, and the rest of the ingredients are the same as in Example 1.

[0031] Example 3 A flame-retardant leather base fabric, which differs from Example 1 in that no resorcinol bis(diphenyl phosphate) is added to the coating layer and the preparation method, and the amount of triphenyl phosphate and the amount of bisphenol A bis(diphenyl phosphate) are 45 g, and the rest are the same as in Example 1.

[0032] Example 4 A flame-retardant leather base fabric, which differs from Example 1 in that bisphenol A bis(diphenyl phosphate) is not added to the coating layer and the preparation method, and triphenyl phosphate is 45g and resorcinol bis(diphenyl phosphate) is 45g, and the rest is the same as Example 1.

[0033] Example 5 A flame-retardant leather base fabric is disclosed. The difference between the flame-retardant leather base fabric and Example 1 lies in that polyether-modified silicone is not added to the coating layer and the preparation method, and the rest of the fabric is the same as Example 1.

[0034] Example 6 A flame-retardant leather base fabric, which differs from Example 1 in that the coating layer and the polyether-modified siloxane in the preparation method are derived from Preparation Example 2.

[0035] Example 7 A flame-retardant leather base fabric, which differs from Example 1 in that the coating layer and the polyether-modified siloxane in the preparation method are derived from Preparation Example 3.

[0036] Example 8 A flame-retardant leather base fabric, which differs from Example 1 in that the coating layer and the polyether-modified siloxane in the preparation method are derived from Preparation Example 4.

[0037] Example 9 A flame-retardant leather base fabric, which differs from Example 1 in that triacetin is used in the coating layer and the preparation method instead of monoacetin.

[0038] Example 10 A flame-retardant leather base fabric is disclosed, which differs from Example 1 in that a carbodiimide is used in the coating layer and the preparation method instead of a trifunctional aziridine cross-linking agent.

[0039] Comparative Example 2 A flame-retardant leather base fabric is prepared from a surface layer and a coating layer, wherein the surface layer is a PET spunbond non-woven fabric, and the coating layer is composed of the following raw materials: 400 g of waterborne polyurethane, 30 g of triphenyl phosphate, 30 g of resorcinol bis(diphenyl phosphate), 30 g of bisphenol A bis(diphenyl phosphate), 5 g of a nano-silver antibacterial agent, 75 g of glycerol monoacetate, 60 g of trifunctional aziridine, 20 g of a sodium polyacrylate aqueous solution, and 12.5 g of a polyether-modified siloxane.

[0040] A flame-retardant leather base fabric, the preparation method of which is as follows: S1: adding waterborne polyurethane into a reactor; S2: At 30°C, sodium polyacrylate aqueous solution, triphenyl phosphate, resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), polyether-modified siloxane, monoacetin, and trifunctional aziridine were added to a reactor in sequence, while dispersing at 600 rpm. After the addition was completed, dispersion was continued at 600 rpm for 20 minutes to obtain a functional slurry; S3: Use functional slurry to impregnate PET spunbond nonwoven fabric for 25 seconds, press at 3kg / cm2, repeat the pressing twice to obtain wet base fabric; S4: drying with hot air at 100° C. at a wind speed of 2.0 m / s for 10 min, and cooling to room temperature of 25° C. to obtain a leather base fabric.

[0041] Comparative Example 3 A flame-retardant leather base fabric is prepared from a surface layer and a coating layer, wherein the surface layer is a PET spunbond non-woven fabric, and the coating layer is composed of the following raw materials: 400 g of waterborne polyurethane, 30 g of triphenyl phosphate, 30 g of resorcinol bis(diphenyl phosphate), 30 g of bisphenol A bis(diphenyl phosphate), 5 g of a nano-silver antibacterial agent, 75 g of glycerol monoacetate, 60 g of trifunctional aziridine, 20 g of a sodium polyacrylate aqueous solution, and 12.5 g of a polyether-modified siloxane.

[0042] A flame-retardant leather base fabric, the preparation method of which is as follows: S1: adding waterborne polyurethane into a reactor; S2: At 30°C, triphenyl phosphate, resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), polyether-modified siloxane, glycerol monoacetate, trifunctional aziridine, and sodium polyacrylate aqueous solution were sequentially added to a reactor while dispersing at 600 rpm. After the addition was completed, dispersion was continued at 600 rpm for 20 minutes to obtain a functional slurry. S3: Use functional slurry to impregnate PET spunbond nonwoven fabric for 25 seconds, press at 3kg / cm2, repeat the pressing twice to obtain wet base fabric; S4: drying with hot air at 100° C. at a wind speed of 2.0 m / s for 10 min, and cooling to room temperature of 25° C. to obtain a leather base fabric.

[0043] Example 11 A flame-retardant leather base fabric, which differs from Example 1 in that a coating layer is composed of the following raw materials: 300 g of water-based polyurethane, 20 g of triphenyl phosphate, 20 g of resorcinol bis(diphenyl phosphate), 20 g of bisphenol A bis(diphenyl phosphate), 1 g of a nano-silver antibacterial agent, 50 g of monoacetin, 40 g of a trifunctional aziridine crosslinking agent, 10 g of a sodium polyacrylate aqueous solution, and 5 g of a polyether-modified siloxane.

[0044] Example 12 A flame-retardant leather base fabric, which differs from Example 1 in that a coating layer is composed of the following raw materials: 500 g of aqueous polyurethane, 50 g of triphenyl phosphate, 50 g of resorcinol bis(diphenyl phosphate), 50 g of bisphenol A bis(diphenyl phosphate), 10 g of nano-silver antibacterial agent, 100 g of monoacetin, 80 g of trifunctional aziridine crosslinking agent, 30 g of sodium polyacrylate aqueous solution, and 20 g of polyether-modified siloxane.

[0045] The flame retardancy and flexibility of Examples 1 to 12 and Comparative Examples 1 to 3 were tested.

[0046] The flame retardancy test was carried out according to the horizontal combustion method in accordance with GB 8410-2006 “Combustion Characteristics of Automotive Interior Materials”. The test results are shown in Table 1.

[0047] Table 1 Flame retardancy test results Burning speed (mm / min) Self-extinguishing time (s) Example 1 82 10 Example 2 89 15 Example 3 92 18 Example 4 88 14 Example 5 83 11 Example 6 82 10 Example 7 81 11 Example 8 83 11 Example 9 89 14 Example 10 82 11 Example 11 90 14 Example 12 81 10 Comparative Example 1 90 16 Comparative Example 2 100 17 Comparative Example 3 102 20 The softness test was carried out according to QB / T 5155-2017 “Test methods for artificial leather and synthetic leather—Determination of softness”. The test results are shown in Table 2.

[0048] Table 2 Softness test results In combination with Table 1 and Table 2, comparing Example 1 and Comparative Example 1, the burning rate and self-extinguishing time of the leather base cloth of Example 1 are less than the burning rate and self-extinguishing time of the leather base cloth of Comparative Example 1, and the draping height and bending stiffness of the leather base cloth of Example 1 are less than the draping height and bending stiffness of the leather base cloth of Comparative Example 1.

[0049] The difference between Example 1 and Comparative Example 1 is that acetylated glyceride is added to the leather base fabric coating layer of Example 1, and the lipophilic fatty acid ester groups and hydrophilic hydroxyl / acetoxy groups of the acetylated glyceride are inserted between the PU polymer segments, weakening the interaction force between the segments, making the molecular segments easier to move, curl and slip, and improving the softness of the material. At the same time, the ester groups of the acetylated glyceride and the phosphate groups in the phosphorus-based flame retardant form a weak cross-linked network through hydrogen bonds or dipole-dipole effects, reducing the migration of small molecules of the flame retardant to the surface of the base fabric and extending the durability of the flame retardant performance. It can be seen that the addition of acetylated glyceride is necessary.

[0050] Comparing Example 1 and Example 2, the burning speed and self-extinguishing time of the leather base fabric in Example 1 are less than the burning speed and self-extinguishing time of the leather base fabric in Example 2, and the draping height and bending stiffness of the leather base fabric in Example 1 are close to the draping height and bending stiffness of the leather base fabric in Example 2.

[0051] The difference between Example 1 and Example 2 is that triphenyl phosphate is added to the leather base fabric coating layer in Example 1. Triphenyl phosphate first decomposes to generate phosphoric acid in the low temperature zone, catalyzing the dehydration of the polymer to form an initial carbon layer. It can be seen that adding triphenyl phosphate is more advantageous.

[0052] Comparing Example 1 and Example 3, the burning speed and self-extinguishing time of the leather base fabric of Example 1 are less than the burning speed and self-extinguishing time of the leather base fabric of Example 3, and the draping height and bending stiffness of the leather base fabric of Example 1 are close to the draping height and bending stiffness of the leather base fabric of Example 3.

[0053] The difference between Example 1 and Example 3 is that in Example 1, resorcinol bis(diphenyl phosphate) is added to the leather base fabric coating layer, and the polyphosphoric acid generated by the decomposition of resorcinol bis(diphenyl phosphate) in the medium temperature zone further cross-links triphenyl phosphate to form a carbon layer to fill the pores. It can be seen that adding resorcinol bis(diphenyl phosphate) is better.

[0054] Comparing Example 1 and Example 4, the burning speed and self-extinguishing time of the leather base fabric of Example 1 are less than the burning speed and self-extinguishing time of the leather base fabric of Example 4, and the draping height and bending stiffness of the leather base fabric of Example 1 are close to the draping height and bending stiffness of the leather base fabric of Example 4.

[0055] The difference between Example 1 and Example 4 is that bisphenol A bis(diphenyl phosphate) is added to the leather base fabric coating layer in Example 1. Bisphenol A bis(diphenyl phosphate) releases gas at high temperature, causing the carbon layer to expand and thicken. It can be seen that adding bisphenol A bis(diphenyl phosphate) is better.

[0056] Comparing Example 1 and Example 5, the burning speed and self-extinguishing time of the leather base fabric of Example 1 are close to the burning speed and self-extinguishing time of the leather base fabric of Example 5, and the draping height and bending stiffness of the leather base fabric of Example 1 are less than the draping height and bending stiffness of the leather base fabric of Example 5.

[0057] The difference between Example 1 and Example 5 is that in Example 1, polyether-modified silicone is added to the leather base fabric coating layer. The molecular structure of polyether-modified silicone makes it tend to migrate and enrich to the surface of the coating layer and the air / solid interface, effectively reducing the friction coefficient of the base fabric surface and improving the softness of the surface feel. It can be seen that adding polyether-modified silicone is better.

[0058] Comparing Example 1 and Example 6, the burning speed and self-extinguishing time of the leather base fabric of Example 1 are close to the burning speed and self-extinguishing time of the leather base fabric of Example 6, and the draping height and bending stiffness of the leather base fabric of Example 1 are less than the draping height and bending stiffness of the leather base fabric of Example 6.

[0059] The difference between Example 1 and Example 6 is that in Example 1, pentamethyldisiloxane and allyl polyoxyethylene ether are dehydrated during the preparation of polyether-modified silicone for leather-based fabric. The dehydration treatment prevents the water in pentamethyldisiloxane and allyl polyoxyethylene ether from poisoning and deactivating the platinum catalyst. It can be seen that it is better to dehydrate pentamethyldisiloxane and allyl polyoxyethylene ether during the preparation of polyether-modified silicone.

[0060] Comparing Example 1 and Example 7, the burning speed and self-extinguishing time of the leather base fabric of Example 1 are close to the burning speed and self-extinguishing time of the leather base fabric of Example 7, and the draping height and bending stiffness of the leather base fabric of Example 1 are less than the draping height and bending stiffness of the leather base fabric of Example 7.

[0061] The difference between Example 1 and Example 7 is that the hydrogen-containing siloxane in the preparation process of polyether-modified silicone for leather-based fabric in Example 1 is pentamethyldisiloxane, and the hydrogen-containing siloxane in the preparation process of polyether-modified silicone for leather-based fabric in Example 7 is 2,4,6,8-tetramethylcyclotetrasiloxane. Pentamethyldisiloxane has a low molecular weight and after reacting with allyl polyether, the modified silicone obtained has a clear molecular structure and a small molecular weight, which effectively plays a role in reducing the friction coefficient and improving the surface smoothness and soft feel of the base fabric. It can be seen that it is better to choose pentamethyldisiloxane as the hydrogen-containing siloxane in the preparation process of polyether-modified silicone.

[0062] Comparing Example 1 and Example 8, the burning speed and self-extinguishing time of the leather base fabric of Example 1 are close to the burning speed and self-extinguishing time of the leather base fabric of Example 8, and the draping height and bending stiffness of the leather base fabric of Example 1 are less than the draping height and bending stiffness of the leather base fabric of Example 8.

[0063] The difference between Example 1 and Example 8 is that the organic alcohol in the preparation process of polyether-modified silicone for leather-based fabric in Example 1 is isopropyl alcohol, and the organic alcohol in the preparation process of polyether-modified silicone for leather-based fabric in Example 8 is n-propyl alcohol. Isopropyl alcohol effectively dissolves and dilutes the platinum catalyst, ensuring that it can be added dropwise to the reaction system in a stable and uniform manner, effectively exerting the role of the platinum catalyst. It can be seen that isopropyl alcohol is a better choice of organic alcohol for the preparation process of polyether-modified silicone.

[0064] Comparing Example 1 and Example 9, the burning speed and self-extinguishing time of the leather base fabric of Example 1 are less than the burning speed and self-extinguishing time of the leather base fabric of Example 9, and the draping height and bending stiffness of the leather base fabric of Example 1 are less than the draping height and bending stiffness of the leather base fabric of Example 9.

[0065] The difference between Example 1 and Example 9 is that the acetylated glycerol ester in the leather base fabric coating layer of Example 1 is monoacetic glycerol ester, and the acetylated glycerol ester in the leather base fabric coating layer of Example 9 is triacetic glycerol ester. The molecular polarity of monoacetic glycerol ester is moderate, and it has better compatibility with the polyurethane system and is not easy to migrate and precipitate. The retained hydroxyl groups can participate in the hydrogen bonding in the polyurethane system and anchor on the polyurethane molecular chain to improve the softness of the body. At the same time, it is not easy to seep out. The steric hindrance of a single acetyl group is small, and the hindrance of inserting between polyurethane chain segments is smaller. Its stronger binding force makes it possible to better improve the overall softness and flexibility of the base fabric at the same dosage. The two free hydroxyl groups undergo a dehydration reaction at the initial stage of combustion to improve the flame retardant effect. It can be seen that it is better to choose monoacetic glycerol ester as the acetylated glycerol ester for the coating layer.

[0066] Comparing Example 1 and Example 10, the burning speed and self-extinguishing time of the leather base fabric of Example 1 are close to the burning speed and self-extinguishing time of the leather base fabric of Example 10, and the draping height and bending stiffness of the leather base fabric of Example 1 are less than the draping height and bending stiffness of the leather base fabric of Example 10.

[0067] The difference between Example 1 and Example 10 is that the crosslinking agent for the leather base fabric coating layer in Example 1 is a trifunctional aziridine crosslinking agent, and the crosslinking agent for the leather base fabric coating layer in Example 10 is a carbodiimide. Under the premise that the trifunctional nitrogen ensures the required strength of the base fabric, a crosslinked network that is not overly rigid and still has a certain chain segment activity is formed, thereby avoiding the base fabric becoming brittle and hard due to excessive crosslinking. It can be seen that it is better to choose a trifunctional aziridine crosslinking agent when adding a crosslinking agent.

[0068] Comparing Example 1 with Comparative Examples 2 to 3, the burning speed and self-extinguishing time of the leather base fabric of Example 1 are less than the burning speed and self-extinguishing time of the leather base fabric of Comparative Example 2, and the draping height and bending stiffness of the leather base fabric of Example 1 are less than the draping height and bending stiffness of the leather base fabric of Comparative Examples 2 to 3.

[0069] The difference between Example 1 and Comparative Examples 2 to 3 is that, in the preparation process of the leather base cloth in Example 1, the polyurethane and the dispersant are first mixed and stirred. The polyurethane and the dispersant ensure that the functional additives are dispersed evenly and stably. Gradual addition helps to prevent agglomeration, so that the various functional components are fully and evenly mixed with the polyurethane, thereby preventing local softness deterioration or surface defects and flame retardancy degradation caused by uneven dispersion or agglomeration. It can be seen that it is necessary to first mix and stir the polyurethane and the dispersant during the preparation process of the leather base cloth.

[0070] Comparing Example 1 with Examples 11-12, the burning rate and self-extinguishing time of the leather base fabric of Example 1 are less than the burning rate and self-extinguishing time of the leather base fabric of Example 11, and the draping height and bending stiffness of the leather base fabric of Example 1 are close to the draping height and bending stiffness of the leather base fabric of Example 11; the burning rate and self-extinguishing time of the leather base fabric of Example 1 are close to the burning rate and self-extinguishing time of the leather base fabric of Example 12, and the draping height and bending stiffness of the leather base fabric of Example 1 are less than the draping height and bending stiffness of the leather base fabric of Example 12.

[0071] The difference between Example 1 and Example 11 is that the mass ratio of the components of the leather base fabric coating layer in Example 11, namely, water-based polyurethane, triphenyl phosphate, resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), nanosilver antibacterial agent, monoacetin, trifunctional aziridine crosslinker, sodium polyacrylate aqueous solution, and polyether modified silicone, is 300:20:20:20:1:50:40:10:5.

[0072] The difference between Example 1 and Example 12 is that the mass ratio of the components of the leather base fabric coating layer in Example 12, namely, water-based polyurethane, triphenyl phosphate, resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), nanosilver antibacterial agent, monoacetin, trifunctional aziridine crosslinker, sodium polyacrylate aqueous solution, and polyether modified silicone, is 500:50:50:50:10:100:80:30:20.

[0073] It can be seen that the mass ratio of the leather base fabric coating layer components, water-based polyurethane, triphenyl phosphate, resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), nanosilver antibacterial agent, monoacetin, trifunctional aziridine crosslinker, sodium polyacrylate aqueous solution, and polyether modified silicone is better at 400:30:30:30:5:75:60:20:12.5.

[0074] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as the modifications are within the scope of protection required by the present invention, they will be protected by patent law.

Claims

1. A flame retardant leather base fabric, characterized in that: It includes a surface layer and a coating layer. The surface layer is PET non-woven fabric, and the coating layer includes the following components in parts by weight: 30-50 parts of polyurethane, 6-15 parts of phosphorus flame retardant, 0.1-1 part of nano silver antibacterial agent, 5-10 parts of acetylated glyceride, 4-8 parts of crosslinking agent, and 1-3 parts of dispersant, wherein the phosphorus flame retardant is at least one of triphenyl phosphate, resorcinol bis(diphenyl phosphate), and bisphenol A bis(diphenyl phosphate).

2. The flame retardant leather base fabric according to claim 1, characterized in that: The coating layer also includes 0.5 to 2 parts of polyether modified silicone.

3. The flame retardant leather base fabric according to claim 2, characterized in that: The polyether-modified siloxane is prepared by the following process: Raw material pretreatment: adding hydrogen-containing siloxane to a reactor, evacuating the reactor and then introducing nitrogen to dehydrate the reactor to obtain dehydrated hydrogen-containing siloxane; dehydrating the allyl polyether to obtain dehydrated allyl polyether; Mixed catalysis: Dehydrated hydrogenated siloxane, dehydrated allyl polyether, and solvent are stirred to obtain a mixed solution, platinum catalyst diluted with organic alcohol is added dropwise to the mixed solution at a constant rate, and the mixture is heated to 90°C and allowed to react to obtain a reaction solution; Post-treatment: After the reaction solution is cooled, activated carbon is added and stirred, filtered, and the solvent is removed in vacuo to obtain an organic phase, which is washed and dehydrated to obtain polyether-modified siloxane.

4. The flame retardant leather base fabric according to claim 3, characterized in that: The hydrogen-containing siloxane used in the preparation of the polyether-modified siloxane is pentamethyldisiloxane.

5. The flame retardant leather base fabric according to claim 3, characterized in that: The organic alcohol used in the preparation process of the polyether-modified siloxane is isopropyl alcohol.

6. The flame retardant leather base fabric according to claim 1, characterized in that: The acetylated glyceride is glyceryl monoacetate.

7. The flame retardant leather base fabric according to claim 1, characterized in that: The cross-linking agent is a trifunctional aziridine cross-linking agent.

8. A method for preparing a flame-retardant leather base fabric according to any one of claims 1 to 7, characterized in that: The following steps are involved: Adding polyurethane and dispersant into a reactor and stirring, gradually adding other components of the coating layer except polyurethane and dispersant, and continuously stirring to obtain a functional slurry; The PET nonwoven fabric is impregnated with the functional slurry to obtain a wet base fabric; After drying, curing and cooling, the leather base fabric is obtained.

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