Flame-retardant latex product with high mechanical property retention rate as well as preparation method and application of flame-retardant latex product

Abstract

The invention belongs to the technical field of latex products, and discloses a flame-retardant latex product with a high mechanical property retention rate as well as a preparation method and application of the flame-retardant latex product. The flame-retardant latex product consists of the following components in parts by mass: 100 parts of natural concentrated latex, 0.9 part of potassium hydroxide, 0.5-3 parts of an accelerant MZ, 1-2 parts of titanium dioxide, 1-8 parts of kaolin, 1-3 parts of sulfur, 1-3 parts of oleic acid, 2-4 parts of an antioxidant, 20 parts of melamine-coated red phosphorus, 4 parts of phytic acid, 0.5-2 parts of carbon nanotubes, 1-3 parts of an accelerant BZ and 2-3 parts of zinc oxide. The pH value of the flame-retardant latex product is adjusted to 11-13 by using ammonia water.

Description

Technical Field

[0001] This invention belongs to the field of latex product technology, and specifically relates to a flame-retardant latex product with high mechanical property retention rate, its preparation method and application. Background Technology

[0002] Natural rubber latex is an aqueous colloidal dispersion system obtained from rubber trees. Its main component is cis-1,4-polyisoprene, but it also contains non-rubber components such as lipids, proteins, and carbohydrates. Products based on natural rubber latex are widely used in high-value, highly sensitive daily necessities and medical and health fields, such as medical gloves, condoms, catheters, sponges, pillows, mattresses, and special clothing, due to their excellent elasticity, flexibility, biocompatibility, and comfortable feel.

[0003] However, natural rubber, as a high-molecular hydrocarbon, has a limiting oxygen index (LOI) of only about 17-18%, making it an extremely flammable material. This poses a significant fire safety hazard when it is in close contact with the human body or used in potential fire-prone environments such as electrical and transportation facilities.

[0004] Unlike common solid rubber compounding processes, latex uses water as the dispersion medium. This characteristic necessitates that flame retardant modification must be carried out in an aqueous phase. Ensuring the long-term dispersion stability of the flame retardant components in the aqueous phase, their interfacial compatibility with the rubber particles, and their uniform and directional distribution within the rubber matrix during subsequent drying and film formation are the primary technical challenges.

[0005] Currently, the technical approach is to improve the flame retardancy of latex by adding halogenated flame retardants, but traditional methods often face serious challenges: the dispersion stability of flame retardants in water-based latex systems is poor, which can easily lead to uneven product performance; the introduction of a large amount of filler can seriously damage the inherent high elasticity, high elongation and soft touch of latex; some flame retardant components may also affect the biosafety and transparency of the product.

[0006] Therefore, how to endow natural latex with efficient and safe flame-retardant functions while maintaining its excellent mechanical properties (such as high tensile strength and elongation at break) and user experience has become a key technical bottleneck for promoting the upgrading of high-end latex products and expanding their application in high-safety-standard scenarios. It is also the current research focus and market demand in the field of material modification. Summary of the Invention

[0007] To overcome the key challenges in the existing technology, such as poor compatibility between flame retardants and natural rubber latex, serious damage to the mechanical properties and durability of the products after addition, and complex processes that are difficult to industrialize, the primary objective of this invention is to provide a flame-retardant latex product with high mechanical property retention rate; to construct a flame-retardant system with excellent compatibility with natural rubber latex system, which significantly improves the flame retardancy rating of latex products while maximizing the retention of their inherent high tensile strength and elongation at break and other mechanical properties.

[0008] Another objective of this invention is to provide a method for preparing the above-mentioned flame-retardant latex product with high mechanical property retention rate; the entire preparation process is reasonably designed, requires no complex equipment, and has significant potential for industrial application.

[0009] Another object of the present invention is to provide an application of the above-mentioned flame-retardant latex product with high mechanical property retention rate.

[0010] The objective of this invention is achieved through the following technical solution: A flame-retardant latex product with high mechanical property retention rate, wherein the flame-retardant latex product is composed of the following components in parts by weight: 100 parts of natural concentrated latex, 0.5-3 parts of accelerator MZ, 1-2 parts of titanium dioxide, 1-8 parts of kaolin, 1-3 parts of sulfur, 1-3 parts of oleic acid, 2-4 parts of antioxidant, 20 parts of melamine-coated red phosphorus, 4 parts of phytic acid, 0.5-2 parts of carbon nanotubes, 0.9 parts of potassium hydroxide, 1-3 parts of accelerator BZ, and 2-3 parts of zinc oxide; the pH value of the flame-retardant latex product is adjusted to 11-13 with ammonia water.

[0011] The flame-retardant latex product has a tensile strength of up to 7.2 MPa, an elongation at break of up to 1032.5%, and an LOI of up to 30.8%.

[0012] The titanium dioxide, kaolin, sulfur, and zinc oxide are ground to a particle size of 1~10μm using a ball mill; the grinding balls in the ball mill are 2mm zirconium dioxide.

[0013] The natural concentrated latex, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant, melamine-coated red phosphorus, phytic acid, and carbon nanotubes are inert materials; the potassium hydroxide, accelerator BZ, and zinc oxide are active materials.

[0014] The accelerator MZ is 2-thiol-benzothiazole zinc salt.

[0015] The accelerator BZ is zinc dimethyl dithiocarbamate.

[0016] The antioxidant is a product of the reaction of p-cresol and dicyclopentadiene butylation.

[0017] The above-mentioned method for preparing a flame-retardant latex product with high mechanical property retention includes the following steps: (1) Under stirring conditions, natural concentrated latex is added to the container and stirred at 200 rpm for 30 minutes. Then, every 15 minutes, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant, melamine-coated red phosphorus, phytic acid and carbon nanotubes are added in sequence. Then, stirring and dispersing is continued for 30 to 60 minutes. (2) Increase the stirring speed to 200-400 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, adjust the pH value to 11-13 with ammonia water, and continue stirring and dispersing for 120 minutes to obtain flame retardant latex. (3) Pour the flame-retardant latex obtained in step (2) into a petri dish, place the petri dish containing the mixed latex into an acid bath, and perform acid coagulation under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid to obtain a solid latex intermediate. (4) The solid latex intermediate obtained in step (3) is washed in warm water at 50~55℃ for 5~10 minutes and then placed in an oven and vulcanized at 112~125℃ for 8~15 minutes to obtain flame-retardant latex products with high mechanical property retention.

[0018] The above-mentioned flame-retardant latex product with high mechanical property retention rate is used in flexible fireproof sealing materials or high-performance protective gloves.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention is a “three-in-one” composite flame retardant system composed of melamine-coated red phosphorus, phytic acid and carbon nanotubes, which is systematically applied to natural latex for the first time.

[0020] (2) The present invention uses carbon nanotubes in a flame-retardant composite system, which not only improves the quality of the char layer formed when the composite material is burned, but also greatly preserves the mechanical properties of the flame-retardant latex, and has a wider application market.

[0021] (3) The possible flame-retardant principle of the flame-retardant latex product of the present invention during combustion is as follows: In the condensed phase, phytic acid and red phosphorus promote char formation and form a carbon layer. The carbon nanotube network structure further strengthens the carbon layer, making the protective barrier more durable. In the gas phase, melamine (e.g., nitrogen) releases non-flammable gas and phytic acid decomposes upon heating. Active factors (e.g., PO·) "eliminate" OH· and H·, and the two work together to retard flame in the gas phase. Attached Figure Description

[0022] Figure 1 The graph shows the limiting oxygen index data of the latex products obtained in Examples 1-10.

[0023] Figure 2 This is a graph showing the tensile test results of latex products. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0025] The titanium dioxide, kaolin, sulfur, and zinc oxide used in the following examples were ground to a particle size of 1-10 μm using a ball mill (the grinding balls were 2 mm zirconium dioxide); the antioxidant was p-cresol and a dicyclopentadiene butylated product.

[0026] Example 1 (Blank Group) A latex product is composed of the following components in parts by weight: 100 parts of natural concentrated latex, 0.9 parts of potassium hydroxide, 2 parts of accelerator MZ, 1.2 parts of titanium dioxide, 5 parts of kaolin, 2 parts of sulfur, 2 parts of oleic acid, 3 parts of antioxidant, 1.5 parts of accelerator BZ, and 2 parts of zinc oxide.

[0027] The latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex is added to the container and stirred at 200 rpm for 30 minutes. Then, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid and antioxidant are added sequentially every 15 minutes. Then, stirring and dispersion are continued for 30 minutes. (2) Increase the stirring speed to 300 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain natural rubber latex. (3) Pour the natural rubber latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid latex intermediate. (4) The solid latex intermediate obtained in step (3) is washed in warm water at 50°C for 5 minutes and then placed in an oven. It is vulcanized at 110°C for 12 minutes and then cooled to obtain the latex product.

[0028] Example 2 A latex product is composed of the following components in parts by weight: 100 parts concentrated latex, 0.9 parts potassium hydroxide, 2 parts accelerator MZ, 1.2 parts titanium dioxide, 6 parts kaolin, 2 parts sulfur, 2 parts oleic acid, 3 parts antioxidant, 0.5 parts carbon nanotubes, 2 parts accelerator BZ, and 2 parts zinc oxide.

[0029] The latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex was added to the container and stirred at 200 rpm for 30 minutes. Then, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant and carbon nanotubes were added sequentially every 15 minutes. Then, stirring and dispersion were continued for 30 minutes. (2) Increase the stirring speed to 300 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the mixed latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid mixed latex intermediate. (4) The solid mixed latex intermediate obtained in step (3) is washed in warm water at 50°C for 5 minutes and then placed in an oven. It is vulcanized at 115°C for 10 minutes and then cooled to obtain the latex product.

[0030] Example 3 A latex product is composed of the following components by mass: 100 parts concentrated latex, 0.9 parts potassium hydroxide, 2 parts accelerator MZ, 1.2 parts titanium dioxide, 6 parts kaolin, 2 parts sulfur, 2 parts oleic acid, 3 parts antioxidant, 1 part carbon nanotubes, 2 parts accelerator BZ, and 2 parts zinc oxide.

[0031] The latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex was added to the container and stirred at 200 rpm for 30 minutes. Then, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant and carbon nanotubes were added sequentially every 15 minutes. Then, stirring and dispersion were continued for 30 minutes. (2) Increase the stirring speed to 300 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the mixed latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid mixed latex intermediate. (4) The solid mixed latex intermediate obtained in step (3) is washed in 50°C warm water for 5 minutes and then placed in an oven. It is vulcanized at 118°C for 10 minutes and then cooled to obtain the latex product.

[0032] Example 4 A latex product is composed of the following components in parts by weight: 100 parts concentrated latex, 0.9 parts potassium hydroxide, 2 parts accelerator MZ, 1.2 parts titanium dioxide, 6 parts kaolin, 2 parts sulfur, 2 parts oleic acid, 3 parts antioxidant, 1.5 parts carbon nanotubes, 2 parts accelerator BZ, and 2 parts zinc oxide.

[0033] The latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex was added to the container and stirred at 200 rpm for 30 minutes. Then, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant and carbon nanotubes were added sequentially every 15 minutes. Then, stirring and dispersion were continued for 30 minutes. (2) Increase the stirring speed to 350 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the mixed latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid mixed latex intermediate. (4) The solid mixed latex intermediate obtained in step (3) is washed in warm water at 55°C for 5 minutes and then placed in an oven. It is vulcanized at 120°C for 12 minutes and then cooled to obtain the latex product.

[0034] Example 5 A latex product is composed of the following components in parts by weight: 100 parts concentrated latex, 0.9 parts potassium hydroxide, 2 parts accelerator MZ, 1.2 parts titanium dioxide, 6 parts kaolin, 2 parts sulfur, 2 parts oleic acid, 3 parts antioxidant, 2 parts carbon nanotubes, 2 parts accelerator BZ, and 2 parts zinc oxide.

[0035] The latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex was added to the container and stirred at 200 rpm for 30 minutes. Then, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant and carbon nanotubes were added sequentially every 15 minutes. Then, stirring and dispersion were continued for 30 minutes. (2) Increase the stirring speed to 350 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the mixed latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid mixed latex intermediate. (4) The solid mixed latex intermediate obtained in step (3) is washed in warm water at 55°C for 5 minutes and then placed in an oven. It is vulcanized at 120°C for 15 minutes and then cooled to obtain the latex product.

[0036] Example 6 A flame-retardant latex product is composed of the following components by mass: 100 parts concentrated latex, 0.9 parts potassium hydroxide, 2.2 parts accelerator MZ, 1.2 parts titanium dioxide, 6 parts kaolin, 2 parts sulfur, 2.6 parts oleic acid, 3 parts antioxidant, 20 parts melamine-coated red phosphorus, 4 parts phytic acid, 2.2 parts accelerator BZ, and 3 parts zinc oxide.

[0037] The flame-retardant latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex is added to the container and stirred at 200 rpm for 30 minutes. Then, every 15 minutes, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant, melamine-coated red phosphorus and phytic acid are added in sequence, and then stirring and dispersing is continued for 30 minutes. (2) Increase the stirring speed to 350 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the mixed latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid latex intermediate. (4) The solid latex intermediate obtained in step (3) is washed in warm water at 55°C for 5 minutes and then placed in an oven. It is vulcanized at 118°C for 10 minutes and then cooled to obtain flame-retardant latex products.

[0038] Example 7 A flame-retardant latex product is composed of the following components by mass parts: 100 parts concentrated latex, 0.9 parts potassium hydroxide, 2.2 parts accelerator MZ, 1.2 parts titanium dioxide, 6 parts kaolin, 2 parts sulfur, 2.6 parts oleic acid, 3 parts antioxidant, 20 parts melamine-coated red phosphorus, 4 parts phytic acid, 0.5 parts carbon nanotubes, 2.2 parts accelerator BZ, and 3 parts zinc oxide.

[0039] The flame-retardant latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex was added to the container and stirred at 200 rpm for 30 minutes. Then, every 15 minutes, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant, melamine-coated red phosphorus, phytic acid and carbon nanotubes were added in sequence and stirred and dispersed for 30 minutes. (2) Increase the stirring speed to 350 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the mixed latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid latex intermediate. (4) The solid latex intermediate obtained in step (3) is washed in warm water at 55°C for 5 minutes and then placed in an oven. It is vulcanized at 120°C for 10 minutes and then cooled to obtain flame-retardant latex products.

[0040] Example 8 A flame-retardant latex product is composed of the following components by mass parts: 100 parts concentrated latex, 0.9 parts potassium hydroxide, 2.2 parts accelerator MZ, 1.2 parts titanium dioxide, 6 parts kaolin, 2 parts sulfur, 2.6 parts oleic acid, 3 parts antioxidant, 20 parts melamine-coated red phosphorus, 4 parts phytic acid, 1 part carbon nanotubes, 2.2 parts accelerator BZ, and 3 parts zinc oxide.

[0041] The flame-retardant latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex was added to the container and stirred at 200 rpm for 30 minutes. Then, every 15 minutes, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant, melamine-coated red phosphorus, phytic acid and carbon nanotubes were added in sequence and stirred and dispersed for 60 minutes. (2) Increase the stirring speed to 350 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the mixed latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid latex intermediate. (4) The solid latex intermediate obtained in step (3) is washed in warm water at 55°C for 5 minutes and then placed in an oven. It is vulcanized at 120°C for 13 minutes and then cooled to obtain flame-retardant latex products.

[0042] Example 9 A flame-retardant latex product is composed of the following components by mass: 100 parts concentrated latex, 0.9 parts potassium hydroxide, 2.2 parts accelerator MZ, 1.2 parts titanium dioxide, 6 parts kaolin, 2 parts sulfur, 2.6 parts oleic acid, 3 parts antioxidant, 20 parts melamine-coated red phosphorus, 4 parts phytic acid, 1.5 parts carbon nanotubes, 2.2 parts accelerator BZ, and 3 parts zinc oxide.

[0043] The flame-retardant latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex was added to the container and stirred at 200 rpm for 30 minutes. Then, every 15 minutes, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant, melamine-coated red phosphorus, phytic acid and carbon nanotubes were added in sequence and stirred and dispersed for 60 minutes. (2) Increase the stirring speed to 400 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the mixed latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid latex intermediate. (4) The solid latex intermediate obtained in step (3) is washed in warm water at 55°C for 5 minutes and then placed in an oven. It is vulcanized at 125°C for 11 minutes and then cooled to obtain flame-retardant latex products.

[0044] Example 10 A flame-retardant latex product is composed of the following components by mass parts: 100 parts concentrated latex, 0.9 parts potassium hydroxide, 2.2 parts accelerator MZ, 1.2 parts titanium dioxide, 6 parts kaolin, 2 parts sulfur, 2.6 parts oleic acid, 3 parts antioxidant, 20 parts melamine-coated red phosphorus, 4 parts phytic acid, 2 parts carbon nanotubes, 2.2 parts accelerator BZ, and 3 parts zinc oxide.

[0045] The flame-retardant latex product of this embodiment is prepared according to the following steps: (1) Under stirring conditions, natural concentrated latex was added to the container and stirred at 200 rpm for 30 minutes. Then, every 15 minutes, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant, melamine-coated red phosphorus, phytic acid and carbon nanotubes were added in sequence and stirred and dispersed for 60 minutes. (2) Increase the stirring speed to 400 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, use ammonia to maintain the pH value at 13, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the mixed latex obtained in step (2) into a petri dish with a diameter of 10 cm, and then place the petri dish into an acid bath. Under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid, acid coagulation is carried out to obtain a solid latex intermediate. (4) The solid latex intermediate obtained in step (3) is washed in warm water at 55°C for 5 minutes and then placed in an oven. It is vulcanized at 125°C for 15 minutes and then cooled to obtain flame-retardant latex products.

[0046] Test example: The latex products obtained in Examples 1-5 and the flame-retardant latex products obtained in Examples 6-10 were cut into test samples using molds and subjected to the following performance tests: (1) Limiting Oxygen Index Test: Oxygen index (LOI) tests were performed on various samples using a JF-3 oxygen index meter (Beijing Zhonghang Times Instrument Equipment Co., Ltd.) according to GB / T10707-2008 standard. The sample dimensions were 100.0 × 6.5 × 3.0 mm. 3 Each group contained 5 to 8 samples, and all values ​​were recorded. The results are shown in Table 1.

[0047] (2) Mechanical properties: Tensile tests were conducted using an E44.304 (Meters Industrial Systems (China) Co., Ltd.) universal testing machine equipped with a 100N sensor, at a tensile speed of 10 mm / s, at room temperature. The results are shown in Table 1. The limiting oxygen index data of the latex products obtained in Examples 1-10 are as follows: Figure 1 As shown, the tensile test results of some latex products obtained in the embodiments are as follows: Figure 2 As shown.

[0048] Table 1 Sample Performance Table

[0049] As shown in Table 1, in the process of exploring high-performance flame-retardant natural latex, it was found that directly adding conventional carbon nanotubes as reinforcing fillers not only failed to improve the flame retardancy of the material as expected, but also led to a regular deterioration in the flame retardant performance of the system. Experimental verification (refer to Examples 1-5) showed that when the amount of carbon nanotubes added gradually increased from 0 parts to 2 parts, the limiting oxygen index of the composite material exhibited a monotonically decreasing trend. In-depth analysis suggests that this phenomenon may be due to the difficulty in achieving uniform dispersion of untreated carbon nanotubes in natural latex, leading to agglomeration and the formation of highly efficient localized thermally conductive networks within the composite material. When the material is ignited, heat is transferred to the interior through these networks, accelerating the thermal decomposition process of the polymer matrix. Furthermore, after adding melamine-coated red phosphorus and phytic acid flame-retardant systems separately (as in Example 6), the mechanical properties of the composite material declined to some extent, but the flame retardant performance was significantly improved.

[0050] However, this invention has found that introducing a melamine-coated red phosphorus and phytic acid composite flame retardant system (refer to Examples 7-10) into a natural latex matrix containing carbon nanotubes can reverse the negative effects of using carbon nanotubes alone. Compared to the control group containing only carbon nanotubes, the limiting oxygen index of the composite material shows an upward trend. This demonstrates that the addition of the melamine-coated red phosphorus and phytic acid system not only overcomes the defects of carbon nanotubes but also synergistically enhances the flame retardant efficiency to a new level.

[0051] As can be seen from the results in Table 1, although the addition of single carbon nanotubes negatively impacted the flame-retardant properties of the system, it enhanced the mechanical properties of the composite material. Experimental data (refer to Examples 1-5) show that the tensile strength and elongation at break of the obtained latex film exhibit a gradually increasing trend. Furthermore, the results in Examples 7-10 also demonstrate this enhancing effect.

[0052] This invention's composite material possesses excellent flame-retardant properties while also exhibiting high retention rates of tensile strength and elongation at break. It successfully overcomes the problem of severe degradation of material mechanical properties caused by traditional flame-retardant modification, opening up entirely new high-safety-level applications in fields with stringent requirements for flexibility and elasticity. Specifically, the material is suitable for high-elasticity flame-retardant latex yarns, comfortable flame-retardant sponges, and flame-retardant adhesives for automotive interiors. In these applications, it can largely retain the inherent comfort and fatigue resistance of natural latex, demonstrating significant market value.

[0053] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A flame-retardant latex product with high mechanical property retention rate, characterized in that: The flame-retardant latex product is composed of the following components by mass: 100 parts of natural concentrated latex, 0.5-3 parts of accelerator MZ, 1-2 parts of titanium dioxide, 1-8 parts of kaolin, 1-3 parts of sulfur, 1-3 parts of oleic acid, 2-4 parts of antioxidant, 20 parts of melamine-coated red phosphorus, 4 parts of phytic acid, 0.5-2 parts of carbon nanotubes, 0.9 parts of potassium hydroxide, 1-3 parts of accelerator BZ, and 2-3 parts of zinc oxide; the pH value of the flame-retardant latex product is adjusted to 11-13 with ammonia water.

2. The flame-retardant latex product with high mechanical property retention rate according to claim 1, characterized in that: The flame-retardant latex product has a tensile strength of up to 7.2 MPa, an elongation at break of up to 1032.5%, and an LOI of up to 30.8%.

3. The flame-retardant latex product with high mechanical property retention rate according to claim 1, characterized in that: The titanium dioxide, kaolin, sulfur, and zinc oxide are ground to a particle size of 1~10μm using a ball mill; the grinding balls in the ball mill are 2mm zirconium dioxide.

4. The flame-retardant latex product with high mechanical property retention rate according to claim 1, characterized in that: The antioxidant is a product of the reaction of p-cresol and dicyclopentadiene butylation.

5. The method for preparing a flame-retardant latex product with high mechanical property retention rate according to claim 1, characterized in that... The following steps are included: (1) Under stirring conditions, natural concentrated latex is added to the container and stirred at 200 rpm for 30 minutes. Then, every 5 to 15 minutes, accelerator MZ, titanium dioxide, kaolin, sulfur, oleic acid, antioxidant, melamine-coated red phosphorus, phytic acid and carbon nanotubes are added in sequence. Then, stirring and dispersing is continued for 30 to 60 minutes. (2) Increase the stirring speed to 200-400 rpm, add potassium hydroxide, and then add accelerator BZ and zinc oxide every 15 minutes. Finally, adjust the pH value to 11-13 with ammonia water, and continue stirring and dispersing for 120 minutes to obtain mixed latex. (3) Pour the flame-retardant latex obtained in step (2) into a petri dish, place the petri dish containing the flame-retardant latex into an acid bath, and perform acid coagulation under the action of an aqueous solution with a mass percentage concentration of 35% acetic acid to obtain a solid latex intermediate. (4) The solid latex intermediate obtained in step (3) is washed in warm water at 50~55℃ for 5~10 minutes and then placed in an oven and vulcanized at 112~125℃ for 8~15 minutes to obtain flame-retardant latex products with high mechanical property retention.

6. The application of the flame-retardant latex product with high mechanical property retention rate according to claim 1 in the application of flexible fireproof sealing materials or high-performance protective gloves.

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