Anti-aging natural latex composite material and preparation method thereof

Abstract

The invention discloses an anti-aging natural latex composite material and a preparation method thereof, and belongs to the technical field of high polymer materials. The anti-aging natural latex composite material is prepared from the following raw materials in parts by weight: 50 to 80 parts of natural latex, 3 to 8 parts of vulcanizing agent, 2 to 5 parts of antioxidant, 3 to 5 parts of zinc oxide, 5 to 10 parts of functional filler, 1 to 3 parts of modification accelerant and 2 to 4 parts of wear-resistant agent, the anti-aging natural latex composite material prepared by the invention has excellent aging resistance and wear resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to an anti-aging natural latex composite material and a preparation method thereof. Background Art

[0002] As a natural polymer material, natural latex has been widely used in many fields such as medical, automotive, construction, household, and additive manufacturing due to its excellent elasticity, flexibility, biodegradability, and biocompatibility. However, with the progress of technology and the continuous improvement of people's requirements for material properties, traditional natural latex materials have gradually revealed some performance deficiencies in additive applications, especially in terms of wear resistance and vulcanization, which limit their further application and development.

[0003] In terms of wear resistance, the application of natural latex products in some high-friction and high-wear environments, such as automotive tires, industrial conveyor belts, and sports equipment, is greatly restricted. This is because there are a large number of active double bonds in the molecular structure of natural latex, which are prone to molecular chain breakage and wear during the friction process, resulting in the gradual loss of luster, scratches, and even damage on the material surface. This not only affects the appearance of the product but also reduces its service life and performance stability, increasing maintenance costs and resource waste.

[0004] In terms of vulcanization, the vulcanization process of natural latex plays a crucial role in its final properties. There are some problems with the traditional sulfur vulcanization system. For example, blooming is likely to occur during the vulcanization reaction process, which not only affects the product appearance but also forms structural defects such as cracks or holes on the surface of the rubber film, reducing the use safety of the product. In addition, the traditional vulcanization system also has deficiencies in improving the aging resistance of natural latex and is difficult to meet some application scenarios with higher durability requirements.

[0005] Chinese Patent Invention Publication No. CN118895019A discloses a high-performance graphene / natural latex composite material and a preparation method thereof. The high-performance graphene / natural latex composite material includes the following raw materials in parts by weight: 100 parts of natural latex; 10 parts of castor oil soap solution; 5 - 8 parts of filler; 0.2 - 0.3 parts of potassium hydroxide; 0.2 - 0.3 parts of stabilizer; 10 - 12 parts of vulcanizing agent; 1 - 2 parts of accelerator; 3 - 4 parts of potassium oleate. This high-performance graphene / natural latex composite material has excellent foaming properties, but has poor tensile strength, aging resistance, and wear resistance. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide an anti-aging natural latex composite material and a preparation method thereof.

[0007] To achieve the above purpose, the present invention is realized through the following technical solutions: An anti-aging natural latex composite material, comprising raw materials in the following parts by weight: Natural latex: 50 - 80 parts, vulcanizing agent: 3 - 8 parts, antioxidant: 2 - 5 parts, zinc oxide: 3 - 5 parts, functional filler: 5 - 10 parts, modified accelerator: 1 - 3 parts, wear-resistant agent: 2 - 4 parts; The modified accelerator is prepared by the following method: S1: 2-Amino-6-chlorobenzothiazole reacts with 2-(2,4-dihydroxyphenyl)-4,6-bis(4-biphenyl)-1,3,5-triazine under the catalysis of potassium carbonate to generate intermediate 1; S2: Intermediate 1 reacts with allyl isothiocyanate under the catalysis of dibutyltin dilaurate to generate intermediate 2; S3: 2-Mercaptobenzothiazole reacts with intermediate 2 under the action of initiator AIBN to generate the modified accelerator.

[0008] In step S1, the feeding molar ratio of 2-amino-6-chlorobenzothiazole to 2-(2,4-dihydroxyphenyl)-4,6-bis(4-biphenyl)-1,3,5-triazine is (2 - 3):1.

[0009] In step S2, the feeding molar ratio of intermediate 1 to allyl isothiocyanate is 1:(2 - 2.5).

[0010] In step S3, the feeding molar ratio of 2-mercaptobenzothiazole to intermediate 2 is (2 - 3):1.

[0011] The wear-resistant agent is prepared by the following method: A1: 7-Octenyltrimethoxysilane reacts with triethylene glycol monoethyl ether to generate a modified silane; A2: The modified silane, 2-(perfluorodecyl)ethyl methacrylate, and pentaerythritol tetraacrylate react to generate the wear-resistant agent.

[0012] In step A1, the feeding mass ratio of 7-octenyltrimethoxysilane to triethylene glycol monoethyl ether is 1:3.5.

[0013] In step A2, the feeding mass ratio of the modified silane, 2-(perfluorodecyl)ethyl methacrylate, and pentaerythritol tetraacrylate is 10:8:3.

[0014] The vulcanizing agent is sulfur; the antioxidant is one of N-isopropyl-N'-phenyl-p-phenylenediamine and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine.

[0015] The functional filler is graphene oxide.

[0016] A preparation method of an anti-aging natural latex composite material, comprising the following steps: (1) Weigh by parts by weight: natural latex: 50 - 80 parts, vulcanizing agent: 3 - 8 parts, antioxidant: 2 - 5 parts, zinc oxide: 3 - 5 parts, functional filler: 5 - 10 parts, modified accelerator: 1 - 3 parts, wear-resistant agent: 2 - 4 parts; (2) Place the natural latex in a high-speed shear mixer for stirring, add the vulcanizing agent, functional filler, modified accelerator, zinc oxide, antioxidant, and wear-resistant agent, continue stirring and curing to obtain a mixture; keep the mixture warm, stir and mix evenly, pour it into a mold, and obtain the anti-aging natural latex composite material through gelling, vulcanization, demolding, and drying.

[0017] An application of the anti-aging natural latex composite material in the field of additive manufacturing.

[0018] Due to the above technical solutions, the beneficial effects of the present invention include: (1) The modified accelerator prepared by the present invention realizes the synchronous optimization of the tensile strength and aging resistance of the composite material through the synergistic effect of three types of functional groups: the rigid triazine ring, the dynamically crosslinked thiourea group, and the antioxidant benzothiazole.

[0019] (2) The pentaerythritol tetraacrylate functional group in the preparation process of the wear-resistant agent prepared by the present invention can form a high-density three-dimensional crosslinked network during the polymerization process, significantly improving the hardness and rigidity of the material and resisting plastic deformation caused by friction; the introduction of fluorinated segments endows the material with low surface energy and lubricity, reducing energy loss and surface wear during friction; the introduced ethoxy segments have flexibility and dynamic reversibility, and local chain segment rearrangement occurs when friction generates heat, repairing surface microcracks and prolonging the wear-resistant life. Specific embodiments

[0020] The following is further described in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0021] Example 1 Preparation of the modified accelerator: S1: Under nitrogen protection, add 400 ml of N,N-dimethylacetamide, 0.1 mol of 2-(2,4-dihydroxyphenyl)-4,6-bis(4-biphenyl)-1,3,5-triazine, and 50 g of anhydrous K2CO3 into the reactor. Stir and mix well, heat up to 80 °C, and then add 0.2 mol of 2-amino-6-chlorobenzothiazole in batches (0.05 mol per batch, with a 20-minute interval between batches). After reacting for 10 h, cool down to room temperature, add 100 ml of anhydrous ethanol and 600 ml of deionized water, stir to precipitate, filter, and then wash three times with deionized water (50 ml of deionized water each time). Then add 300 ml of anhydrous ethanol for recrystallization, filter, and dry in vacuum at 70 °C for 2 h to obtain Intermediate 1; the reaction equation is shown as follows:

[0022] S2: Add 400 ml of anhydrous ethanol, 0.1 mol of Intermediate 1, and 0.01 mol of dibutyltin dilaurate into the reactor. Stir and mix well, heat up to 40 °C, and then slowly dropwise add 0.2 mol of allyl isothiocyanate over 30 min. After the addition, react for 6 h, then cool down to room temperature and keep warm for 45 h. Add 100 ml of cyclohexane, stir for 10 min to precipitate, and then wash three times with cyclohexane (50 ml of cyclohexane each time). Dry in vacuum at 50 °C for 4 h to obtain Intermediate 2; the reaction equation is shown as follows:

[0023] S3: Under nitrogen protection, add 500 ml of DMSO, 0.2 mol of 2-mercaptobenzothiazole, and 0.1 mol of Intermediate 2 into the reactor. Stir and mix well, heat up to 80 °C, and then add 12 g of initiator AIBN. After reacting for 24 h, cool down to room temperature, distill under reduced pressure at 60 °C for 3 h, and separate through a silica gel column to obtain the modified accelerator; the reaction equation is shown as follows:

[0024] The 1H NMR data are as follows: 11H NMR (500 MHz, Chloroform-d) δ 9.68 (s, 2H), 8.93 (t, J = 3.8 Hz, 2H), 8.16 – 8.09 (m, 4H), 8.03 – 7.92 (m, 3H), 7.82 (ddd, J = 7.0, 1.5, 0.5 Hz, 2H), 7.79 – 7.72 (m, 6H), 7.61 – 7.54 (m, 4H), 7.52 – 7.37 (m, 12H), 7.06 – 6.94 (m, 3H), 6.65 (d, J = 2.3 Hz, 1H), 3.57 (td, J = 5.5, 3.8 Hz, 4H), 3.21 (t, J = 6.7 Hz, 4H), 2.05 – 1.96 (m, 4H). Example 2 Preparation of modified accelerator: S1: Under nitrogen protection, add 400 ml of N,N-dimethylacetamide, 0.1 mol of 2-(2,4-dihydroxyphenyl)-4,6-bis(4-biphenyl)-1,3,5-triazine, and 50 g of anhydrous K2CO3 into the reactor, stir and mix evenly, heat up to 90 °C, and then add 0.25 mol of 2-amino-6-chlorobenzothiazole in batches (0.05 mol per batch, batch interval 20 min). After reacting for 9 h, cool down to room temperature, add 100 ml of anhydrous ethanol and 600 ml of deionized water, stir to precipitate, filter, and then wash three times with deionized water (50 ml of deionized water each time). Then add 300 ml of anhydrous ethanol for recrystallization, filter, and vacuum dry at 70 °C for 2 h to obtain Intermediate 1; S2: Add 400 ml of anhydrous ethanol, 0.1 mol of Intermediate 1, and 0.01 mol of dibutyltin dilaurate into the reactor, stir and mix evenly, heat up to 50 °C, and then slowly dropwise add 0.22 mol of allyl isothiocyanate dropwise for 30 min. After dropping, react for 5 h, then cool down to room temperature and keep warm for 48 h. Then add 100 ml of cyclohexane, stir for 10 min, precipitate, and then wash three times with cyclohexane (50 ml of cyclohexane each time). Vacuum dry at 50 °C for 4 h to obtain Intermediate 2; S3: Under nitrogen protection, add 500 ml of DMSO, 0.25 mol of 2-mercaptobenzothiazole, and 0.1 mol of Intermediate 2 into the reactor, stir and mix evenly, heat up to 85 °C, and then add 12 g of initiator AIBN. After reacting for 22 h, cool down to room temperature, distill under reduced pressure at 60 °C for 3 h, and separate by silica gel column to obtain the modified accelerator.

[0025] Example 3 Preparation of modified accelerator: S1: Under nitrogen protection, add 400 ml of N,N-dimethylacetamide, 0.1 mol of 2-(2,4-dihydroxyphenyl)-4,6-bis(4-biphenyl)-1,3,5-triazine, and 50 g of anhydrous K2CO3 into the reactor. Stir and mix evenly, heat up to 100 °C, and then add 0.3 mol of 2-amino-6-chlorobenzothiazole in batches (0.05 mol per batch, with a 20-minute interval between batches). After reacting for 8 h, cool down to room temperature, add 100 ml of anhydrous ethanol and 600 ml of deionized water, stir to precipitate, filter, and then wash three times with deionized water (50 ml of deionized water each time). Then add 300 ml of anhydrous ethanol for recrystallization, filter, and dry in vacuum at 70 °C for 2 h to obtain intermediate 1; S2: Add 400 ml of anhydrous ethanol, 0.1 mol of intermediate 1, and 0.01 mol of dibutyltin dilaurate into the reactor. Stir and mix evenly, heat up to 60 °C, and then slowly dropwise add 0.25 mol of allyl isothiocyanate dropwise over 30 min. After dropping, react for 4 h, then cool down to room temperature and keep warm for 42 h. Then add 100 ml of cyclohexane, stir for 10 min, precipitate, and then wash three times with cyclohexane (50 ml of cyclohexane each time). Dry in vacuum at 50 °C for 4 h to obtain intermediate 2; S3: Under nitrogen protection, add 500 ml of DMSO, 0.3 mol of 2-mercaptobenzothiazole, and 0.1 mol of intermediate 2 into the reactor. Stir and mix evenly, heat up to 90 °C, and then add 12 g of initiator AIBN. After reacting for 20 h, cool down to room temperature, distill under reduced pressure at 60 °C for 3 h, and separate by silica gel column to obtain the modified accelerator.

[0026] Example 4 Preparation of wear-resistant agent: S1: Under nitrogen protection, add 200 ml of toluene, 10 g of 7-octenyltrimethoxysilane, 35 g of triethylene glycol ethyl ether, and 3 ml of 93 wt% concentrated sulfuric acid into the reactor. Heat up to 100 °C, after reacting for 8 h, add 50 ml of deionized water to quench the reaction, centrifuge and filter, add 50 ml of n-hexane for washing, and dry in vacuum at 70 °C for 3 h to obtain the modified silane; S2: Under nitrogen protection, add 1000 ml of toluene, 100 g of modified silane, 80 g of 2-(perfluorodecyl)ethyl methacrylate, and 30 g of pentaerythritol tetraacrylate into the reactor. Stir and mix evenly, heat up to 80 °C, add 10 g of AIBN, after reacting for 6 h, distill under reduced pressure at 60 °C for 3 h, and dry in vacuum at 70 °C for 2 h to obtain the wear-resistant agent.

[0027] Example 5 Preparation of anti-aging natural latex composite material: (1)Weigh: natural latex: 500 g, vulcanizing agent (sulfur): 30 g, antioxidant (N-isopropyl-N'-phenyl-p-phenylenediamine): 20 g, zinc oxide: 30 g, functional filler (graphene oxide): 50 g, modified accelerator (prepared in Example 1): 10 g, wear-resistant agent (prepared in Example 4): 20 g; (2)Place the natural latex in a high-speed shear mixer and stir at a speed of 5000 r / min for 30 min. Then add the vulcanizing agent, functional filler, modified accelerator, zinc oxide, antioxidant, and wear-resistant agent, and continue stirring at a speed of 3000 r / min for 40 min. Cure at 40 °C for 10 h to obtain a mixture. Keep the mixture at 50 °C for 2 h, stir and mix well, pour it into a mold, and gel at 110 °C for 20 min, vulcanize at 120 °C for 1 h, demold, and dry at 60 °C for 6 h to obtain the anti-aging natural latex composite material.

[0028] Example 6 Preparation of anti-aging natural latex composite material: (1)Weigh: natural latex: 600 g, vulcanizing agent (sulfur): 50 g, antioxidant (N-isopropyl-N'-phenyl-p-phenylenediamine): 30 g, zinc oxide: 40 g, functional filler (graphene oxide): 80 g, modified accelerator (prepared in Example 2): 20 g, wear-resistant agent (prepared in Example 4): 30 g; (2)Place the natural latex in a high-speed shear mixer and stir at a speed of 5000 r / min for 30 min. Then add the vulcanizing agent, functional filler, modified accelerator, zinc oxide, antioxidant, and wear-resistant agent, and continue stirring at a speed of 3000 r / min for 40 min. Cure at 40 °C for 10 h to obtain a mixture. Keep the mixture at 50 °C for 2 h, stir and mix well, pour it into a mold, and gel at 110 °C for 20 min, vulcanize at 120 °C for 1 h, demold, and dry at 60 °C for 6 h to obtain the anti-aging natural latex composite material.

[0029] Example 7 Preparation of anti-aging natural latex composite material: (1)Weigh: natural latex: 800 g, vulcanizing agent (sulfur): 80 g, antioxidant (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 50 g, zinc oxide: 50 g, functional filler (graphene oxide): 100 g, modified accelerator (prepared in Example 3): 30 g, wear-resistant agent (prepared in Example 4): 40 g; (2)Place natural latex in a high-speed shear mixer and stir at a speed of 5000 r / min for 30 min. Then add vulcanizing agent, functional filler, modified accelerator, zinc oxide, antioxidant, and wear-resistant agent, and continue stirring at a speed of 3000 r / min for 40 min. Cure at 40 °C for 10 h to obtain a mixture. Keep the mixture at 50 °C for 2 h, stir and mix evenly, pour it into a mold, and subject it to gelling at 110 °C for 20 min, vulcanization at 120 °C for 1 h, demolding, and drying at 60 °C for 6 h to obtain the anti-aging natural latex composite material.

[0030] Comparative Example 1 An anti-aging natural latex composite material, whose raw material composition and process are basically the same as those in Example 6, except that the modified accelerator is replaced with a modified accelerator prepared by the following method with the same weight: The preparation method of the modified accelerator in this comparative example is basically the same as that in Example 2, except that 2-amino-6-chlorobenzothiazole added in step S1 is replaced with p-chloroaniline with the same weight.

[0031] Comparative Example 2 An anti-aging natural latex composite material, whose raw material composition and process are basically the same as those in Example 6, except that the modified accelerator is replaced with a modified accelerator prepared by the following method with the same weight: The preparation method of the modified accelerator in this comparative example is basically the same as that in Example 2, except that allyl isothiocyanate added in step S2 is replaced with allyl isocyanate with the same weight.

[0032] Comparative Example 3 An anti-aging natural latex composite material, whose raw material composition and process are basically the same as those in Example 6, except that the modified accelerator is replaced with a modified accelerator prepared by the following method with the same weight: Under nitrogen protection, add 500 ml of DMSO, 0.25 mol of 2-mercaptobenzothiazole, and 0.1 mol of allyl isothiocyanate to a reactor, stir and mix evenly, heat up to 85 °C, then add 12 g of initiator AIBN, react for 22 h, cool to room temperature, and perform vacuum distillation at 60 °C for 3 h, and obtain the modified accelerator by silica gel column separation.

[0033] Comparative Example 4 An anti-aging natural latex composite material, whose raw material composition and process are basically the same as those in Example 6, except that the modified accelerator is replaced with a modified accelerator prepared by the following method with the same weight: The preparation method of the modified accelerator in this comparative example is basically the same as that in Example 2, except that 2-mercaptobenzothiazole added in step S3 is replaced with 5,6-di-p-tolyl-[1,2,4]triazine-3-thiol with the same weight.

[0034] Comparative Example 5 An anti-aging natural latex composite material, the raw material composition and process are basically the same as those in Example 6, the difference is that the wear-resistant agent is replaced with a wear-resistant agent prepared by the following method with the same weight: Under nitrogen protection, add 1000 ml of toluene, 100 g of 7-octenyltrimethoxysilane, 80 g of 2-(perfluorodecyl)ethyl methacrylate, and 30 g of pentaerythritol tetraacrylate into the reactor, stir and mix evenly, heat up to 80 °C, add 10 g of AIBN, after reacting for 6 h, carry out reduced pressure distillation at 60 °C for 3 h, and carry out vacuum drying at 70 °C for 2 h to obtain the wear-resistant agent.

[0035] Comparative Example 6 An anti-aging natural latex composite material, the raw material composition and process are basically the same as those in Example 6, the difference is that the wear-resistant agent is replaced with a wear-resistant agent prepared by the following method with the same weight: The preparation method of the modified accelerator in this comparative example is basically the same as that in Example 4, the difference is that the pentaerythritol tetraacrylate added in step S2 is replaced with an equal weight of dipentaerythritol hexaacrylate.

[0036] The natural latex used in the examples and comparative examples of this application has a rubber content mass fraction of 60% and is purchased from Yunnan Natural Rubber Industry Group Co., Ltd.; the sulfur is the special sulfur powder of type S-80 produced by Qingdao Luchuan Chemical Co., Ltd., mesh number: 400 mesh; the graphene oxide model is OBO-GO-P1 and is purchased from Shandong Oubo New Materials Co., Ltd.

[0037] The anti-aging natural latex composites prepared in the examples and comparative examples were subjected to tensile strength tests. The samples to be tested were prepared into dumbbell-shaped standard specimens. Referring to the standard "ASTM D412-2016", at room temperature (25 °C), the tensile strength and elongation at break of the specimens were tested at a tensile speed of 500 mm / min; after the specimens were aged in a hot air aging box at 100 °C for 10 days, the tensile strength and elongation at break of the aged specimens were tested again under the same test conditions.

[0038] The anti-aging natural latex composites prepared in the examples and comparative examples were subjected to wear resistance experimental tests. The experiments were carried out with reference to GB / T1689-2014, and the results are shown in Table 1.

[0039] Table 1 Performance indicators

[0040] It can be seen from Examples 5, 6, and 7 in Table 1 that the anti-aging natural latex composites prepared by the present invention have excellent aging resistance and wear resistance.

[0041] The triazine ring introduced by the modified accelerator prepared in the present invention has a highly symmetric rigid planar structure, which can enhance the rigidity of the molecular chain and the intermolecular force, thereby improving the tensile strength of the material; the introduction of 4,6-bis(4-biphenyl) increases the steric hindrance and rigidity of the molecular structure, restricts the slippage of the molecular chain, and improves the tensile strength. The thiourea generated in Intermediate 2 can be used as a vulcanization accelerator to accelerate the rubber cross-linking reaction and form a denser cross-linked network, thereby increasing the elongation at break of the material. The allyl group introduced by allyl isothiocyanate can form a thioether bond with the mercapto group of 2-mercaptobenzothiazole through a free radical reaction, further strengthening the cross-linked network. The benzothiazole ring contains sulfur and nitrogen heteroatoms, which can enhance the intermolecular force through hydrogen bonding or dipole interaction. At the same time, its rigid structure inhibits the relaxation of the molecular chain and improves the tensile strength.

[0042] In addition, the high resonance stability and heat resistance of the triazine ring can effectively resist thermal-oxidative aging and delay the thermal degradation of the polymer chain; the large volume of the biphenyl group can hinder the diffusion of oxygen molecules into the interior of the material and slow down the oxidation reaction rate. The sulfur atom in the thiourea structure can capture free radicals, terminate the oxidation chain reaction, and delay aging. The conjugated structure of the benzothiazole ring can absorb ultraviolet light and reduce the chain breakage and cross-linking damage caused by ultraviolet rays.

[0043] The perfluoroalkyl chain of the wear-resistant agent prepared in the present invention has an extremely low surface energy, endowing the material surface with excellent anti-adhesion and self-lubrication properties, reducing the energy loss and surface wear during the friction process. The high bond energy and strong polarity of the C-F bond make the fluorocarbon chain highly stable to chemical corrosion and oxidation, avoiding chemical degradation during the friction process. Pentaerythritol tetraacrylate contains four acrylate groups, which can form a high-density three-dimensional cross-linked network during the polymerization process, significantly improving the hardness and rigidity of the material and resisting the plastic deformation caused by friction; the tetrafunctional structure helps to form a uniform cross-linking, reduce local stress concentration, and improve the overall wear resistance. The ethoxy chain segment introduced by triethylene glycol monoethyl ether has flexibility and dynamic reversibility, and local chain segment rearrangement occurs when friction generates heat, repairing surface microcracks and extending the wear-resistant life.

[0044] In Comparative Example 1, the tensile strength is relatively low and the aging resistance is poor. This is because the benzothiazole ring in 2-amino-6-chlorobenzothiazole has a planar rigid structure and a conjugated π system, which can enhance the intermolecular force through π-π stacking and hydrogen bonding and improve the tensile strength. p-Chloroaniline contains only one benzene ring and an amino group, lacks the rigid skeleton of the heterocycle, and the intermolecular force is significantly reduced, resulting in easy slippage of the molecular chain and a decrease in tensile strength.

[0045] In Comparative Example 2, allyl isothiocyanate reacts with Intermediate 1 to form thiourea. This dynamic bond can disperse stress through reversible cleavage-recombination during the stretching process. After replacing it with allyl isocyanate, a carbamate structure is formed, and its dynamic reversibility is significantly reduced, resulting in the inability of the material to effectively reorganize the crosslinked network under stress and prone to brittle fracture. In addition, sulfur atoms have the ability to capture free radicals and can delay oxidative aging.

[0046] In Comparative Example 3, Intermediate 1 was not added during the preparation of the modified accelerator. The absence of the rigid triazine skeleton led to insufficient mechanical support, resulting in poor tensile properties and aging resistance.

[0047] Comparative Example 4 has poor tensile properties. This is because the 5,6-di-p-tolyl-[1,2,4]triazine-3-thiol molecule contains two p-tolyl groups and a triazine ring thiol group, with a complex structure and large steric hindrance, which affects its dispersibility in latex and the reactivity of the vulcanization reaction, resulting in poor tensile properties of the composite material prepared therefrom.

[0048] Comparative Example 5 has poor wear resistance. This is because if the triethylene glycol ethyl ether segment is missing in the wear-resistant agent, the flexibility of the molecular chain decreases, and microcracks are easily generated and propagated during the friction process, resulting in an accelerated wear rate.

[0049] Comparative Example 6 has poor wear resistance. This is because the dipentaerythritol skeleton of dipentaerythritol hexaacrylate results in a larger molecular volume, leading to a decrease in the dispersibility of the wear-resistant agent.

[0050] As described above, the above are only the preferred embodiments of the present invention and are not used to limit the present invention; however, for those of ordinary skill in the art, without departing from the scope of the technical solution of the present invention, any equivalent changes such as slight modifications, refinements, and evolutions made using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. An anti-aging natural latex composite material, characterized in that, It comprises raw materials in the following parts by weight: Natural latex: 50 - 80 parts, vulcanizing agent: 3 - 8 parts, antioxidant: 2 - 5 parts, zinc oxide: 3 - 5 parts, functional filler: 5 - 10 parts, modified accelerator: 1 - 3 parts, wear-resistant agent: 2 - 4 parts; The modified accelerator is prepared by the following method: S1: 2 - Amino - 6 - chlorobenzothiazole reacts with 2-(2,4 - dihydroxyphenyl)-4,6 - bis(4 - biphenyl)-1,3,5 - triazine under the catalysis of potassium carbonate to generate intermediate 1; S2: Intermediate 1 reacts with allyl isothiocyanate under the catalysis of dibutyltin dilaurate to generate intermediate 2; S3: 2 - Mercaptobenzothiazole reacts with intermediate 2 under the action of an initiator to generate the modified accelerator.

2. The anti-aging natural latex composite material according to claim 1, characterized in that, In step S1, the feeding molar ratio of 2 - amino - 6 - chlorobenzothiazole to 2-(2,4 - dihydroxyphenyl)-4,6 - bis(4 - biphenyl)-1,3,5 - triazine is (2 - 3):

1.

3. The anti-aging natural latex composite material according to claim 1, characterized in that, In step S2, the feeding molar ratio of intermediate 1 to allyl isothiocyanate is 1:(2 - 2.5).

4. An anti-aging natural latex composite material according to claim 1, characterized in that, In step S3, the feeding molar ratio of 2 - mercaptobenzothiazole to intermediate 2 is (2 - 3):

1.

5. The anti-aging natural latex composite material according to claim 1, characterized in that, In step S3, the initiator is AIBN.

6. The anti-aging natural latex composite material according to claim 1, characterized in that, The wear-resistant agent is prepared by the following method: A1: 7 - Octenyltrimethoxysilane reacts with triethylene glycol ethyl ether to generate a modified silane; A2: The modified silane, 2-(perfluorodecyl)ethyl methacrylate, and pentaerythritol tetraacrylate react to generate the wear-resistant agent.

7. An anti-aging natural latex composite material according to claim 6, characterized in that, In step A1, the feeding mass ratio of 7 - octenyltrimethoxysilane to triethylene glycol ethyl ether is 1:3.

5.

8. An anti-aging natural latex composite material according to claim 6, characterized in that, In step A2, the feeding mass ratio of the modified silane, 2-(perfluorodecyl)ethyl methacrylate, and pentaerythritol tetraacrylate is 10:8:

3.

9. The anti-aging natural latex composite material according to claim 1, characterized in that, The vulcanizing agent is sulfur.

10. The anti-aging natural latex composite material according to claim 1, wherein, The antioxidant is one of N - isopropyl - N'-phenyl - p - phenylenediamine and N-(1,3 - dimethylbutyl)-N'-phenyl - p - phenylenediamine.

11. An anti-aging natural latex composite material according to claim 1, characterized in that, The functional filler is graphene oxide.

12. A method for preparing the anti-aging natural latex composite material according to any one of claims 1-11, characterized in that, It comprises the following steps: (1) Weigh by parts by weight: natural latex: 50 - 80 parts, vulcanizing agent: 3 - 8 parts, antioxidant: 2 - 5 parts, zinc oxide: 3 - 5 parts, functional filler: 5 - 10 parts, modified accelerator: 1 - 3 parts, wear-resistant agent: 2 - 4 parts; (2) Place the natural latex in a high-speed shear mixer for stirring, add the vulcanizing agent, functional filler, modified accelerator, zinc oxide, antioxidant, and wear-resistant agent, continue stirring and curing to obtain a mixture; keep the mixture warm, pour it into a mold, and obtain the anti-aging natural latex composite material through gelling, vulcanizing, demolding, and drying.

13. Use of an anti-aging natural latex composite material as described in claims 1 - 11 in the field of additive manufacturing.

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