A high-performance butadiene-pyridine latex and its preparation method

Abstract

This invention belongs to the field of synthetic latex technology, specifically relating to a high-performance butadiene-pyridine latex and its preparation method. The preparation method includes the following steps: (1) ultrasonically dispersing a silane coupling agent containing a long straight carbon chain with double bonds and silica into a solvent, heating and reacting for a period of time, and then adding a silane coupling agent containing a short straight carbon chain with thiol groups to continue the reaction, thereby obtaining a modified silica solution; (2) adding the modified silica solution to a blend of butadiene-pyridine latex and natural latex; (3) adding a vulcanizing agent and an additive, thereby obtaining a high-performance butadiene-pyridine latex. The long chains in the silane coupling agent containing a long straight carbon chain with double bonds can extend into the rubber matrix, providing good stress buffering through physical entanglement and double bond action. The short-chain thiol groups in the silane coupling agent containing a short straight carbon chain with thiol groups can form a large number of strong covalent bonds with the rubber during vulcanization, firmly locking the filler in the network, thereby improving the adhesive properties of the latex.

Description

Technical Field

[0001] This invention belongs to the field of synthetic latex technology, specifically relating to a high-performance butadiene-pyridine latex and its preparation method. Background Technology

[0002] Latex is a stable colloidal dispersion system formed by polymer particles dispersed in an aqueous medium. Latex is classified into natural latex, synthetic latex, and artificial latex according to its source and uses. It is commonly used in industry, agriculture, medicine, transportation, sports, electronics, and daily life, among other applications.

[0003] Synthetic latex is generally an aqueous dispersion of polymer particles produced by emulsion polymerization of monomers, which is then concentrated by methods such as paste formation and agglomeration to increase the size of the rubber particles. Synthetic latex is mainly used in non-pure rubber products, and to a smaller extent in pure rubber products, such as carpets, textiles, sponges, impregnated products, papermaking, tire manufacturing, and adhesives. Synthetic latex has advantages such as low variability, stable quality, resistance to spoilage, a wide variety of types, and good specific properties; however, its colloidal strength is not as high as that of natural rubber. Commonly used synthetic latexes include styrene-butadiene latex, butyl rubber latex, butadiene latex, butyl latex, chloroprene latex, ethylene-propylene latex, isoprene latex, nitrile latex, and acrylic latex, with butyl rubber latex being the most widely used.

[0004] The emulsion polymerization of butadiene-pyridine latex is a free radical addition copolymerization reaction in an emulsion system, which can be divided into chain initiation, chain propagation, chain transfer, and chain termination reactions. In addition, some cross-linking reactions between macromolecules also occur. Butadiene, styrene, and 2-vinylpyridine form a polymer copolymer under the action of free radical initiation. Emulsion polymerization can be classified into batch emulsion polymerization, semi-continuous emulsion polymerization, continuous emulsion polymerization, and seed emulsion polymerization according to different processes. Currently, the emulsion polymerization of butadiene-pyridine latex mostly adopts the traditional polymerization method, namely semi-continuous emulsion polymerization. In this process, some monomers and auxiliaries such as initiators, emulsifiers, and dispersion media are added to the reactor. After the polymerization reaction reaches a certain conversion rate, the remaining monomers, initiators, emulsifiers, and other auxiliaries are added to the reactor at certain time intervals according to a certain program to continue polymerization until the desired conversion rate is reached, at which point the reaction ends. The polymerization process of butyl pyridine latex is generally a stop (batch) polymerization process. That is, according to the polymerization formula, the required monomers and additives are sent from the storage tank to the polymerization reactor in batches. The polymerization is carried out in stages under stirring and set temperature. When the conversion rate of monomers reaches about 95%, a terminator is added to end the reaction.

[0005] Because the nitrogen atoms on the pyridine ring have paired electrons, they can form hydrogen bonds and dipole bonds with active sites on the fiber surface, resulting in much higher adhesive strength than other latexes. This makes butyl pyridine latex an excellent adhesive for fibers and rubber, mainly used in the impregnation of rayon, nylon, polyester fiber and other tire cord fabrics, and widely used in high-strength tires, hoses, conveyor belts and other rubber products for aircraft and automobiles. Summary of the Invention

[0006] In view of this, the present invention provides a high-performance butyl-pyridine latex and its preparation method. The method provides a high-performance butyl-pyridine latex using butyl-pyridine latex as raw material, and obtaining a modified latex by adding natural latex and modified silica. The process of the present invention is simple and the reaction conditions are mild.

[0007] The technical solution of the present invention: A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) The silane coupling agent containing a long straight carbon chain with double bonds and silica are ultrasonically dispersed in a solvent, heated and reacted for a period of time, and then the silane coupling agent containing a short straight carbon chain with mercapto is added to continue the reaction to obtain a modified silica solution; the number of carbon atoms in the long straight carbon chain with double bonds is 8-18, and the number of carbon atoms in the short straight carbon chain with mercapto is 2-4; the total mass ratio of the silane coupling agent containing the long straight carbon chain with double bonds and the silane coupling agent containing the short straight carbon chain with mercapto is 1-5%; the molar ratio of the silane coupling agent containing the long straight carbon chain with double bonds to the silane coupling agent containing the short straight carbon chain with mercapto is (0.1-0.3):1; (2) Add modified silica solution to the blend of butadiene-pyridine latex and natural latex, and stir until homogeneous; (3) Add vulcanizing agent and additives, and continue to stir evenly to obtain a high-performance butadiene-pyridine latex.

[0008] Butadiene-pyridine latex (also known as styrene-butadiene-pyridine latex) has good stability, but its colloidal strength is low. To improve its strength, this invention adds a certain amount of natural latex. Products impregnated with natural latex exhibit excellent properties, such as high tensile strength, resilience, and shape retention, which are unmatched by many synthetic elastomers. However, natural latex has poor compatibility with silica, resulting in limited reinforcing effect of silica. Existing technologies typically use short-chain silane coupling agents to modify silica, but these still cannot effectively solve the technical problems of difficult silica dispersion and compatibility.

[0009] Therefore, this invention employs a dual modification of silica using a silane coupling agent with long, straight carbon chains containing double bonds and a silane coupling agent with short, straight carbon chains containing mercapto groups. First, the silane coupling agent with long, straight carbon chains containing double bonds modifies the silica, primarily addressing the issues of physical interface compatibility and primary dispersion: the long, straight carbon chains improve the dispersibility and compatibility of silica in rubber, reducing agglomeration; the terminal double bonds provide a reaction anchor point for subsequent covalent bonding. Then, a secondary modification is performed using a silane coupling agent with short, straight carbon chains containing mercapto groups, aiming to establish a strong, dynamic chemical bond between silica and the rubber matrix. The short chains of the silane coupling agent with short, straight carbon chains containing mercapto groups are more flexible and easily access reaction sites. Its terminal mercapto groups are highly reactive during vulcanization, capable of chemically reacting with the double bonds on the rubber molecular chains and the vulcanization system to form strong covalent bonds, deeply participating in the vulcanization network, and improving the mechanical and aging resistance properties of the rubber. Therefore, the long chains in silane coupling agents containing long, straight carbon chains with double bonds can extend into the rubber matrix, providing excellent stress buffering through physical entanglement and double bond interactions. The short-chain thiol groups in silane coupling agents containing short, straight carbon chains with thiol groups can form numerous strong covalent bonds with the rubber during vulcanization, firmly locking the filler within the network.

[0010] It is important to note that the modification process should begin with pretreatment using a small amount of silane coupling agent containing long, straight carbon chains with double bonds, followed by modification with a silane coupling agent containing short, straight carbon chains with thiol groups. Grafting the silane coupling agent with long, straight carbon chains with double bonds first forms an organic layer on the surface of the silica, altering its surface energy and facilitating the uniform grafting of thiol silanes in the solvent. If a highly reactive silane coupling agent containing short, straight carbon chains with thiol groups is grafted first, the thiol groups may oxidize or undergo side reactions during the treatment process, and the steric hindrance of the silane coupling agent with long, straight carbon chains with double bonds makes effective grafting difficult. A small amount of silane coupling agent with long, straight carbon chains with double bonds can effectively improve the dispersibility of silica; however, excessive amounts not only increase costs but also form multiple layers of coating on the silica surface, affecting performance.

[0011] Overall, pretreatment with silane coupling agents containing long, straight carbon chains with double bonds prevented the re-agglomeration of silica in latex. Silane coupling agents containing short, straight carbon chains with mercapto groups provided the strongest chemical bonding, significantly improving tensile stress, abrasion resistance, tear resistance, and dynamic fatigue performance. They also reduced slippage at the filler-polymer interface during deformation, thereby reducing heat generation and improving elasticity.

[0012] In one embodiment, the silane coupling agent containing a long straight carbon chain with double bonds in step (1) has the structural formula CH2=CH-X-Si-Y3, where X is a straight carbon chain alkyl group with 6-16 carbon atoms, and Y is an alkoxy group with 1-4 carbon atoms. Specifically, the silane coupling agent containing a long straight carbon chain with double bonds is one or more of the following: octenyltrimethoxysilane, octenyltriethoxysilane, nonenyltrimethoxysilane, nonenyltriethoxysilane, decenyltrimethoxysilane, decenyltriethoxysilane, undecenyltrimethoxysilane, undecenyltriethoxysilane, dodecenyltrimethoxysilane, dodecenyltriethoxysilane, tetradecenyltrimethoxysilane, tetradecenyltriethoxysilane, hexadecenyltrimethoxysilane, and hexadecenyltriethoxysilane. Furthermore, silane coupling agents with different chain lengths containing long, straight carbon chains with double bonds can be selected, i.e., silane coupling agents with different values ​​for X. For example, octenyltrimethoxysilane and undecenyltrimethoxysilane can be selected. Silane coupling agents with different chain lengths can better control the interfacial layer structure and properties between silica and the rubber matrix.

[0013] In one embodiment, the ultrasonic time in step (1) is 20-40 min. Specifically, it can be 20 min, 25 min, 30 min, 35 min, or 40 min. A suitable ultrasonic time can sufficiently promote the dispersion of the components.

[0014] In one embodiment, the heating temperature in step (1) is 70-75°C. Specifically, it can be 70°C, 71°C, 72°C, 73°C, 74°C, or 75°C. If the reaction temperature is too low, the modification will be incomplete, and a large amount of silane coupling agent will not be effectively grafted, mainly existing in the form of physical adsorption, resulting in poor modification effect. If the reaction temperature is too high, self-condensation reaction easily occurs between silanols, and silane coupling agent molecules connect with each other in the aqueous phase to form cyclic or long-chain siloxane oligomers or even cross-linked polymers, which is not conducive to the modification process.

[0015] In one embodiment, the heating reaction in step (1) lasts for 2-4 hours, followed by a further reaction time of 4-8 hours. Alternatively, the heating reaction lasts for 2.5-3.5 hours, followed by a further reaction time of 5-7 hours. A suitable reaction time allows the silane coupling agent to fully hydrolyze and form covalent bonds with the surface of silica, while maximally suppressing the self-condensation of the silane coupling agent.

[0016] In one embodiment, the silane coupling agent containing a thiol short straight carbon chain in step (1) has the structural formula SH-X-Si-Y3, where X is a straight carbon chain alkyl group with 2-4 carbon atoms and Y is an alkoxy group with 1-4 carbon atoms.

[0017] In one embodiment, step (1) involves one or more of the following silane coupling agents containing a short, straight carbon chain with a mercapto group: γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyldiethoxymethoxysilane, and γ-mercaptopropyldiethoxyethoxysilane.

[0018] In one embodiment, the mass ratio of butyl pyridine latex to natural latex in step (2) (the mass of butyl pyridine latex and natural latex in this invention is based on dry rubber) is (1-1.2):1. In particular, it can be 1:1, 1.1:1 or 1.2:1. Butyl pyridine latex has good weather resistance, and the surfactants contained in the latex can adjust the viscosity of the system and promote the dispersion of each component.

[0019] In one embodiment, the mass ratio of silica to the total mass of butadiene-pyridine latex and natural latex in step (2) is (23-28):100. There is no particular limitation on the type of silica; any commonly used silica in the art is acceptable. The particle size of silica is generally between 15-40 nm. Using modified silica as a reinforcing filler can optimize the dispersion state and interfacial bonding of the filler at the molecular scale, thereby maximizing the reinforcing potential of silica.

[0020] In one embodiment, the sulfiding agent in step (3) is sulfur.

[0021] In one embodiment, the additives in step (3) include accelerators and zinc oxide. In particular, surfactants, anti-scorching agents, compatibilizers, fillers, antioxidants, anti-ozone agents, light stabilizers, anti-fatigue agents, plasticizers, dispersants, thickeners, colorants and other additives may also be added.

[0022] In one embodiment, the accelerator in step (3) is one or more of accelerator CZ, accelerator D, accelerator M, accelerator DM, accelerator CZ, accelerator AZ, and accelerator DZ.

[0023] In one embodiment, the mass ratio of vulcanizing agent, accelerator, zinc oxide to total mass of butadiene-pyridine latex and natural latex in step (3) is (1.3-1.7):(0.4-0.6):(1.7-2.3):100.

[0024] On the other hand, the present invention also provides a high-performance butadiene-pyridine latex prepared by the above method. The present invention uses wet blending technology to complete the mixing and dispersion of minor components and rubber in the latex, which has significant advantages in increasing the amount of fillers in the rubber formulation, improving filler dispersibility, and energy saving and environmental protection. Furthermore, because various operations are carried out in the aqueous phase, the dispersibility of fillers, sulfur, and accelerators is better, thereby resulting in better physical and mechanical properties of the obtained latex (i.e., rubber paste), such as tensile properties and tear properties.

[0025] Beneficial effects: This invention provides a high-performance butadiene-pyridine latex and its preparation method. The method uses butadiene-pyridine latex as raw material and adds natural latex and modified silica to obtain a modified latex with significantly enhanced tear strength and temperature resistance. First, silica is modified with a silane coupling agent containing long, straight carbon chains with double bonds. Then, a secondary modification is performed with a silane coupling agent containing short, straight carbon chains with thiol groups, aiming to establish a strong and dynamic chemical bond between silica and the rubber matrix. The short chains of the silane coupling agent containing short, straight carbon chains with thiol groups are more flexible and easily access reaction sites. The terminal thiol groups are highly reactive during vulcanization, reacting chemically with the double bonds on the rubber molecular chain and the vulcanization system to form strong covalent bonds, deeply participating in the vulcanization network. Therefore, the long chains in the silane coupling agent containing long, straight carbon chains with double bonds can extend into the rubber matrix, providing good stress buffering through physical entanglement and double bond interactions. The short-chain thiol groups in silane coupling agents containing thiol-containing short straight carbon chains can form a large number of strong covalent bonds with rubber during vulcanization, firmly locking the filler in the network and improving the adhesion properties of the latex. Detailed Implementation

[0026] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention are described in detail below with reference to examples. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Unless otherwise specified, the types of raw materials and processes used in the following embodiments are the same.

[0027] Performance Testing: The high-performance butadiene-pyridine latex prepared in the following examples and comparative examples was poured into a container and fully impregnated with polyester-cotton fiber cloth. After drying, the impregnation was repeated three times to obtain a polyester-cotton fiber cloth composite material. Then, two pieces of the polyester-cotton fiber cloth composite material were bonded together and vulcanized at 150°C to obtain a peel sample. After cutting, a peel specimen was obtained. Its 180° peel performance was tested according to GB / T2792-2014; its 180° peel heat-oxidative aging resistance after aging at 100°C for 24 hours was tested according to GB / T3512-2014.

[0028] Example 1

[0029] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Octenyltrimethoxysilane and silica were ultrasonically dispersed in deionized water for 20 min, reacted at 70 °C for 3.5 h, and then γ-mercaptopropyltrimethoxysilane was added and the reaction was continued for 4 h to obtain a modified silica solution; the total mass of octenyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane to silica was 1%; the molar ratio of octenyltrimethoxysilane to γ-mercaptopropyltrimethoxysilane was 0.3:1; (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.2:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 23:100.

[0030] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.7:0.6:2.3:100. The peel strength of the peel test samples before and after aging is 1.65 N / mm and 1.61 N / mm, respectively.

[0031] Example 2

[0032] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Undecenyltrimethoxysilane and silica were ultrasonically dispersed in deionized water for 40 min, reacted at 75 °C for 2 h, and then γ-mercaptopropyltrimethoxysilane was added and the reaction was continued for 8 h to obtain a modified silica solution; the total mass of undecenyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane to silica was 5%; the molar ratio of undecenyltrimethoxysilane to γ-mercaptopropyltrimethoxysilane was 0.1:1; (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, add modified silica solution and stir evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 28:100.

[0033] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.3:0.4:1.7:100. The peel strength of the peel test samples before and after aging is 1.86 N / mm and 1.79 N / mm, respectively.

[0034] Example 3

[0035] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Octenyltrimethoxysilane and silica were ultrasonically dispersed in deionized water for 30 min, reacted at 74 °C for 3 h, and then γ-mercaptopropyltrimethoxysilane was added and the reaction was continued for 6 h to obtain a modified silica solution; the total mass of octenyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane to silica was 3.6%; the molar ratio of octenyltrimethoxysilane to γ-mercaptopropyltrimethoxysilane was 0.2:1; (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.15:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 26:100.

[0036] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.5:0.5:2.1:100. The peel strength of the peel test samples before and after aging is 1.78 N / mm and 1.72 N / mm, respectively.

[0037] Example 4

[0038] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Two coupling agents, octenyltrimethoxysilane and undecenyltrimethoxysilane, with a molar ratio of 3:1, and silica were ultrasonically dispersed in deionized water for 27 min, reacted at 71 °C for 3.8 h, and then γ-mercaptopropyltrimethoxysilane was added to continue the reaction for 4.5 h to obtain a modified silica solution; the total mass of octenyltrimethoxysilane, undecenyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane to silica was 1.5%; the total molar amount of octenyltrimethoxysilane and undecenyltrimethoxysilane to γ-mercaptopropyltrimethoxysilane was 0.18:1; (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.05:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 24:100.

[0039] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.3:0.6:1.6:100. The peel strength of the peel test samples before and after aging is 1.68 N / mm and 1.59 N / mm, respectively.

[0040] Example 5

[0041] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Undecenyltrimethoxysilane and silica were ultrasonically dispersed in deionized water for 30 min, reacted at 74 °C for 3 h, and then γ-mercaptopropyltrimethoxysilane was added and the reaction was continued for 6 h to obtain a modified silica solution; the total mass of undecenyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane to silica was 3.6%; the molar ratio of undecenyltrimethoxysilane to γ-mercaptopropyltrimethoxysilane was 0.2:1; (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.15:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 26:100.

[0042] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.5:0.5:2.1:100. The peel strength of the peel test samples before and after aging is 1.80 N / mm and 1.71 N / mm, respectively.

[0043] Example 6

[0044] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Two coupling agents, octenyltrimethoxysilane and undecenyltrimethoxysilane, with a molar ratio of 1:3, and silica were ultrasonically dispersed in deionized water for 25 min. After reacting at 72℃ for 3 h, γ-mercaptopropyltrimethoxysilane was added and the reaction was continued for 5 h to obtain a modified silica solution. The total mass of octenyltrimethoxysilane, undecenyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane was 2.5% of the total mass of silica. The total molar mass of octenyltrimethoxysilane and undecenyltrimethoxysilane was 0.15:1 of the molar mass of γ-mercaptopropyltrimethoxysilane. (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.08:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 25:100.

[0045] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.45:0.45:1.9:100. The peel strength of the peel test samples before and after aging is 1.76 N / mm and 1.69 N / mm, respectively.

[0046] Example 7

[0047] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Two coupling agents, octenyltrimethoxysilane and undecenyltrimethoxysilane, with a molar ratio of 1:1, and silica were ultrasonically dispersed in deionized water for 30 min. After reacting at 74 °C for 4 h, γ-mercaptopropyltrimethoxysilane was added and the reaction was continued for 6 h to obtain a modified silica solution. The total mass of octenyltrimethoxysilane, undecenyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane was 3.6% of the total mass of silica. The total molar mass of octenyltrimethoxysilane and undecenyltrimethoxysilane was 0.2:1 of the molar mass of γ-mercaptopropyltrimethoxysilane. (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.15:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 26:100.

[0048] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.5:0.5:2.1:100. The peel strength of the peel test samples before and after aging is 1.75 N / mm and 1.70 N / mm, respectively.

[0049] Example 8

[0050] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Octenyltrimethoxysilane and silica were ultrasonically dispersed in deionized water for 35 min, reacted at 74 °C for 2.5 h, and then γ-mercaptopropyltrimethoxysilane was added and the reaction was continued for 7 h to obtain a modified silica solution; the total mass of octenyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane to silica was 4%; the molar ratio of octenyltrimethoxysilane to γ-mercaptopropyltrimethoxysilane was 0.25:1; (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.1:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 27:100.

[0051] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.62:0.55:2.22:100. The peel strength of the peel test samples before and after aging is 1.77 N / mm and 1.68 N / mm, respectively.

[0052] Example 9

[0053] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Two coupling agents, octenyltrimethoxysilane and undecenyltrimethoxysilane, with a molar ratio of 5:1, and silica were ultrasonically dispersed in deionized water for 30 min, reacted at 72℃ for 2.8 h, and then γ-mercaptopropyltrimethoxysilane was added to continue the reaction for 6.5 h to obtain a modified silica solution; the total mass of octenyltrimethoxysilane, undecenyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane to silica was 2.8%; the total molar amount of octenyltrimethoxysilane and undecenyltrimethoxysilane to γ-mercaptopropyltrimethoxysilane was 0.22:1; (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.12:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 25.5:100.

[0054] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide to the total mass of butadiene-pyridine latex and natural latex is 1.48:0.52:1.95:100. The peel strength of the peel test samples before and after aging is 1.73 N / mm and 1.67 N / mm, respectively.

[0055] Example 10

[0056] A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Two coupling agents, octenyltrimethoxysilane and undecenyltrimethoxysilane, with a molar ratio of 1:1, and silica were ultrasonically dispersed in deionized water for 30 min. After reacting at 74 °C for 3 h, γ-mercaptopropyltrimethoxysilane was added and the reaction was continued for 6 h to obtain a modified silica solution. The total mass of octenyltrimethoxysilane, undecenyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane was 3.6% of the total mass of silica. The total molar mass of octenyltrimethoxysilane and undecenyltrimethoxysilane was 0.2:1 of the molar mass of γ-mercaptopropyltrimethoxysilane. (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.15:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 26:100.

[0057] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.5:0.5:2.1:100. The peel strength of the peel test samples before and after aging is 1.85 N / mm and 1.79 N / mm, respectively.

[0058] Comparative Example 1 A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) γ-mercaptopropyltrimethoxysilane and silica were ultrasonically dispersed in deionized water for 30 min and reacted at 74 °C for 3 h. Then, two coupling agents, octenyltrimethoxysilane and undecenyltrimethoxysilane, with a molar ratio of 1:1, were added and the reaction was continued for 6 h to obtain a modified silica solution. The total mass of octenyltrimethoxysilane, undecenyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane was 3.6% of the total mass of silica. The total molar mass of octenyltrimethoxysilane and undecenyltrimethoxysilane was 0.2:1 of the molar mass of γ-mercaptopropyltrimethoxysilane. (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.15:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 26:100.

[0059] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.5:0.5:2.1:100. The peel strength of the peel test samples before and after aging is 1.57 N / mm and 1.45 N / mm, respectively.

[0060] Comparative Example 2 A method for preparing high-performance butadiene-pyridine latex includes the following steps: (1) Two coupling agents, octenyltrimethoxysilane and undecenyltrimethoxysilane, with a molar ratio of 1:1, and silica were ultrasonically dispersed in deionized water for 30 min. After reacting at 74 °C for 3 h, γ-mercaptopropyltrimethoxysilane was added and the reaction was continued for 6 h to obtain a modified silica solution. The total mass of octenyltrimethoxysilane, undecenyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane was 3.6% of the total mass of silica. The total molar mass of octenyltrimethoxysilane and undecenyltrimethoxysilane was 0.7:1 of the molar mass of γ-mercaptopropyltrimethoxysilane. (2) After diluting the blended latex of butyl piezoresistive latex and natural latex with water, a modified silica solution is added and stirred evenly; the mass ratio of butyl piezoresistive latex to natural latex is 1.15:1; the mass ratio of silica to the total mass of butyl piezoresistive latex and natural latex is 26:100.

[0061] (3) Add sulfur, accelerator DM, and zinc oxide, and continue stirring until homogeneous to obtain a high-performance butadiene-pyridine latex; the mass ratio of sulfur, accelerator DM, zinc oxide, and the total mass of butadiene-pyridine latex and natural latex is 1.5:0.5:2.1:100. The peel strength of the peel test samples before and after aging is 1.60 N / mm and 1.49 N / mm, respectively.

[0062] As can be seen from the above examples and comparative examples, pretreatment with silane coupling agents containing long, straight carbon chains with double bonds prevents the re-agglomeration of silica in latex. Silane coupling agents containing short, straight carbon chains with mercapto groups provide the strongest chemical bonding, significantly improving tear resistance and dynamic fatigue performance, reducing slippage at the filler-polymer interface during deformation, thereby reducing heat generation and improving elasticity. This invention employs wet blending technology to complete the mixing and dispersion of fillers and rubber in latex, offering significant advantages in increasing the amount of filler in rubber formulations, improving filler dispersibility, and energy conservation and environmental protection. Furthermore, because various operations are performed in the aqueous phase, the dispersibility of fillers, sulfur, and accelerators is better, thus improving the physical and mechanical properties of the resulting latex, such as peel strength.

[0063] Specifically, compared to Example 10, Comparative Example 1 first used a silane coupling agent containing thiol-containing short straight carbon chains to modify silica. During the treatment process, the thiol groups would undergo oxidation or side reactions, and the subsequent steric hindrance of the silane coupling agent containing double-bond long straight carbon chains made it difficult to effectively graft, thus failing to effectively improve the latex bonding performance. In Comparative Example 2, the excessive amount of silane coupling agent containing double-bond long straight carbon chains would form a multi-layer coating on the silica surface, which would not only affect the dispersion performance of silica but also hinder the modification of the silane coupling agent containing thiol-containing short straight carbon chains, thereby reducing the product's bonding performance.

[0064] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described; these embodiments not explicitly stated should also be considered within the scope of this specification. Although the present invention has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing high-performance butadiene-pyridine latex, characterized in that, Includes the following steps: (1) A silane coupling agent containing a long straight carbon chain with double bonds and silica are ultrasonically dispersed in a solvent. After heating and reacting for a period of time, a silane coupling agent containing a short straight carbon chain with thiol is added to continue the reaction, resulting in a modified silica solution. The silane coupling agent containing a long straight carbon chain with double bonds has the structural formula CH2=CH-X-Si-Y3, where X is a straight carbon chain alkyl group with 6-16 carbon atoms and Y is an alkoxy group with 1-4 carbon atoms. The silane coupling agent containing a short straight carbon chain with thiol has the structural formula SH-X-Si- Y3, X is a straight-chain alkyl group with 2-4 carbon atoms, and Y is an alkoxy group with 1-4 carbon atoms; the total mass ratio of the silane coupling agent containing a long straight-chain double bond and the silane coupling agent containing a short straight-chain mercapto group to the precipitated silica is 1-5%; the molar ratio of the silane coupling agent containing a long straight-chain double bond to the silane coupling agent containing a short straight-chain mercapto group is (0.1-0.3):1; the heating temperature is 70-75℃; the heating reaction time is 2-4 hours, and the reaction time continues for 4-8 hours; (2) Add modified silica solution to the blend of butadiene-pyridine latex and natural latex, and stir until homogeneous; (3) Add vulcanizing agent and additives, and continue to stir evenly to obtain a high-performance butadiene-pyridine latex.

2. The method for preparing a high-performance butadiene-pyridine latex as described in claim 1, characterized in that, The ultrasound time in step (1) is 20-40 min.

3. The method for preparing a high-performance butadiene-pyridine latex as described in claim 1, characterized in that, In step (2), the mass ratio of butyl pyridine latex to natural latex is (1-1.2):

1.

4. The method for preparing a high-performance butadiene-pyridine latex as described in claim 1, characterized in that, In step (2), the mass ratio of silica to the total mass of butadiene-pyridine latex and natural latex is (23-28):

100.

5. The method for preparing a high-performance butadiene-pyridine latex as described in claim 1, characterized in that, In step (3), the sulfiding agent is sulfur.

6. A high-performance butadiene-pyridine latex, characterized in that, It is prepared by the method for preparing a high-performance butadiene-pyridine latex according to any one of claims 1-5.