Anti-aging latex material and preparation method thereof

Abstract

The invention discloses an anti-aging latex material and a preparation method thereof, and relates to the technical field of rubber materials. When the anti-aging latex material is prepared, pentaerythritol and vinylboronic acid react to prepare a pentaerythritol borate monomer; the preparation method comprises the following steps: reacting 1, 1, 3, 3, 5, 5-hexamethyltrisiloxane with a pentaerythritol borate monomer to prepare a boron-silicon composite flame retardant; the preparation method comprises the following steps: reacting lanthanum chloride with 4-ethylene-2-hydroxybenzoic acid to prepare an organic lanthanum rare earth complex; the preparation method comprises the following steps: sequentially reacting chitosan with diallyl chlorophosphate and 1H-benzimidazole-2-mercaptan to obtain modified chitosan; mixing raw butadiene rubber, carbon black, the modified chitosan, the organic lanthanum rare earth complex, the boron-silicon composite flame retardant, zinc oxide, stearic acid, sulfur and an accelerant, and plastifying and vulcanizing to obtain the anti-aging latex material. The anti-aging latex material prepared by the invention has excellent anti-aging performance and flame retardant performance.

Description

Technical Field

[0001] This invention relates to the field of rubber materials technology, specifically to an anti-aging latex material and its preparation method. Background Technology

[0002] Rubber is indispensable in our daily lives; many items (including tires, home appliances, food packaging, shoes, etc.) contain rubber components to varying degrees. Rubber, especially unsaturated rubber (such as natural rubber, butadiene rubber, and styrene-butadiene rubber), is prone to aging during processing, storage, and use due to the presence of unsaturated double bonds in its macromolecular backbone, caused by factors such as heat, oxygen, light, and ozone. Rubber aging first leads to a significant reduction in key properties such as hardness, elasticity, abrasion resistance, and tensile strength, drastically shortening the lifespan of rubber products. Second, rubber aging damages the appearance of rubber products, typically causing discoloration, unpleasant odors, and surface cracks. Furthermore, rubber aging can cause the internal structure of rubber products to loosen and break, creating safety hazards; for example, aged tires pose a risk of blowout, and aged electrical wires can cause electrical fires.

[0003] Butadiene rubber (BR) is the world's second most widely used synthetic rubber. Its relatively regular molecular chain structure gives it excellent properties, making it widely applicable in industrial production. However, BR has poor flame retardancy and low thermal conductivity. During use, heat accumulates continuously, reducing the service life of rubber composites and, in severe cases, even causing them to burn.

[0004] In order to improve the durability and safety of rubber products, it is necessary to invent a rubber material with superior anti-aging and flame-retardant properties. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-aging latex material and its preparation method to solve the problems existing in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] An anti-aging latex material, by weight parts, comprises: 98-102 parts butadiene rubber raw rubber, 20-24 parts carbon black, 6-7 parts modified chitosan, 4-5 parts organolanthanum rare earth complex, 7-8 parts borosilicate composite flame retardant, 3-4 parts zinc oxide, 2-2.4 parts stearic acid, 1.3-1.5 parts sulfur, and 1-1.2 parts accelerator;

[0008] The modified chitosan was prepared by reacting chitosan sequentially with diallyl chlorophosphate and 1H-benzimidazole-2-thiol;

[0009] The organolanthanum rare earth complex is prepared by reacting lanthanum chloride and 4-ethylene-2-hydroxybenzoic acid.

[0010] The borosilicate composite flame retardant is prepared by reacting 1,1,3,3,5,5-hexamethyltrisiloxane and pentaerythritol borate monomers.

[0011] The pentaerythritol borate monomer is prepared by reacting pentaerythritol and vinylboric acid.

[0012] A method for preparing an anti-aging latex material, the method comprising the following preparation steps:

[0013] (1) 1,1,3,3,5,5-hexamethyltrisiloxane and pentaerythritol borate monomers were added to toluene at a molar ratio of 1:(1.2~1.4) to 18~20 times the mass of pentaerythritol borate monomers. Chloroplatinic acid was added at 0.04~0.06 times the mass of pentaerythritol borate monomers. The mixture was stirred at 70~80℃ and 100~200r / min for 6~7h. Toluene was removed by rotary evaporation under reduced pressure. The mixture was washed 3 times each with anhydrous ethanol and deionized water. The mixture was dried at 70~80℃ for 10~12h under vacuum to obtain borosilicate composite flame retardant.

[0014] (2) Weigh out lanthanum chloride, 4-ethylene-2-hydroxybenzoic acid, and sodium hydroxide in a molar ratio of 1:3:3; mix lanthanum chloride and anhydrous ethanol in a mass ratio of 1:(8~10) to prepare a lanthanum chloride solution; prepare a sodium hydroxide aqueous solution with a concentration of 2mol / L; mix 4-ethylene-2-hydroxybenzoic acid and anhydrous ethanol in a mass ratio of 1:(20~24) to prepare a solution, and stir at 55~65℃ and 200~300r / min for 10~20min. Sodium hydroxide aqueous solution was added dropwise at a uniform rate over 5 min. After the addition was complete, the reaction was stirred for 40-50 min. The temperature was lowered to 50℃, and lanthanum chloride solution was added dropwise at a uniform rate over 20 min. After the addition was complete, the reaction was stirred for 4-5 h. The pH of the solution was adjusted to 6.6-7 with 6% sodium hydroxide aqueous solution. The solution was allowed to stand at room temperature for 12-14 h, filtered, and washed three times each with anhydrous ethanol and deionized water. The solution was dried under vacuum at 36-40℃ for 20-24 h to obtain the organolanthanum rare earth complex.

[0015] (3) Premodified chitosan, 1H-benzimidazole-2-thiol, azobisisobutyronitrile, and N,N-dimethylformamide are mixed evenly in a mass ratio of 1:(3~4):(0.1~0.2):(26~28), stirred at 70~80℃ and 200~300r / min for 5~6h, the solvent is evaporated, washed 3 times with anhydrous ethanol, and dried at 50~60℃ under vacuum for 10~12h to obtain modified chitosan;

[0016] (4) Weigh out 98-102 parts by weight of butadiene rubber raw rubber, 20-24 parts of carbon black (N330), 6-7 parts of modified chitosan, 4-5 parts of organolanthanum rare earth complex, 7-8 parts of borosilicate composite flame retardant, 3-4 parts of zinc oxide, 2-2.4 parts of stearic acid, 1.3-1.5 parts of sulfur, and 1-1.2 parts of accelerator (TBBS); place carbon black (N330), zinc oxide, stearic acid, butadiene rubber raw rubber, and borosilicate composite flame retardant in a mixer at 120-150 rpm. Mix at 30℃ for 10 minutes, then place in a two-roll mill for plasticizing. Plasticize at 40~50℃ for 1~2 minutes, add modified chitosan and organic lanthanum rare earth complex, mix for 5~6 minutes, add sulfur and accelerator (TBBS), mix for 3~4 minutes, form a triangular bag, pass through a thin tube 6~8 times, and discharge to obtain the compound rubber. Place the compound rubber at room temperature for 24 hours, then vulcanize and press it into sheets in a flat vulcanizing machine for 10 minutes at a vulcanization temperature of 160℃ to obtain the anti-aging latex material.

[0017] As an optimization, the preparation method of the pentaerythritol borate monomer in step (1) is as follows: pentaerythritol and vinyl boric acid are added to benzene at a molar ratio of 1:(2~2.2) to 14~16 times the mass of pentaerythritol, and stirred at 78°C and 300~500r / min for 7~8h. Then, the mixture is dried at 60~70°C under vacuum for 8~10h to obtain the pentaerythritol borate monomer.

[0018] As an optimization, the reaction mechanism of the borosilicate composite flame retardant in step (1) is as follows:

[0019] .

[0020] As an optimization, the reaction mechanism of the organolanthanum rare earth complex in step (2) is as follows:

[0021] .

[0022] As an optimization, the preparation method of the pre-modified chitosan in step (3) is as follows: chitosan, diallyl chlorophosphate, and triethylamine are weighed in a mass ratio of 1:(2~3):(0.3~0.4); diallyl chlorophosphate and methanol are mixed evenly in a mass ratio of 1:(8~10) to prepare a diallyl chlorophosphate solution; chitosan and methanol are mixed evenly in a mass ratio of 1:(50~60), stirred at 200~300 r / min for 1~2 h at room temperature, triethylamine is added and mixed evenly, the temperature is raised to 60℃, and diallyl chlorophosphate solution is added dropwise at a uniform rate within 25 min under stirring at 200~300 r / min. After the addition is completed, the reaction is continued to be stirred for 7~8 h, the solvent is evaporated, and the mixture is washed 3 times each with methanol and deionized water. Under vacuum conditions, it is dried at 50~60℃ for 10~12 h to obtain the pre-modified chitosan.

[0023] As an optimization, the CAS number of the diallyl chlorophosphate is 16383-57-6; the structural formula is: .

[0024] As an optimization, the degree of deacetylation of the chitosan is 90%, and the weight-average molecular weight is 85 kDa.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] In preparing the anti-aging latex material, this invention involves reacting pentaerythritol and vinyl boric acid to obtain pentaerythritol borate monomer; reacting 1,1,3,3,5,5-hexamethyltrisiloxane and pentaerythritol borate monomer to obtain a borosilicate composite flame retardant; reacting lanthanum chloride and 4-ethylene-2-hydroxybenzoic acid to obtain an organolanthanum rare earth complex; reacting chitosan sequentially with diallyl chlorophosphate and 1H-benzimidazole-2-thiol to obtain modified chitosan; and mixing butadiene rubber raw rubber, carbon black, modified chitosan, organolanthanum rare earth complex, borosilicate composite flame retardant, zinc oxide, stearic acid, sulfur, and accelerator, followed by plasticizing and vulcanization to obtain the anti-aging latex material.

[0027] First, pentaerythritol borate monomer is prepared by reacting pentaerythritol and vinyl boric acid. Then, the Si-H bond on 1,1,3,3,5,5-hexamethyltrisiloxane is subjected to hydrosilylation reaction with the carbon-carbon double bond on the pentaerythritol borate monomer to polymerize and obtain borosilicate composite flame retardant. During the reaction, the pentaerythritol borate monomer is ensured to be in excess. The obtained borosilicate composite flame retardant is end-capped by carbon-carbon double bonds. The addition of borosilicate composite flame retardant can improve the flame retardant performance of anti-aging latex materials, and the carbon-carbon double bonds at both ends can participate in the vulcanization process of rubber.

[0028] Secondly, an organolanthanum rare earth complex was prepared by reacting lanthanum chloride with 4-ethylene-2-hydroxybenzoic acid. 4-ethylene-2-hydroxybenzoic acid contains a carboxylic acid group, and the lanthanum ion coordinates with this carboxylic acid group to form the organolanthanum rare earth complex. Rubber aging is caused by the presence of numerous unsaturated double bonds in the rubber molecular chain, which readily react with oxygen in the air. The numerous empty orbitals of rare earth elements have a strong ability to bind with free radicals, terminating the chain reaction, effectively inhibiting oxidation, and improving the anti-aging performance of anti-aging latex materials. Existing research shows that low-molecular-weight anti-aging components easily migrate from the rubber surface, causing "blooming," which reduces anti-aging efficiency and affects the product's appearance. The carbon-carbon double bonds introduced into the organolanthanum rare earth complex can participate in the rubber vulcanization process, fixing the organolanthanum rare earth complex in the rubber through chemical bonds and preventing the loss of anti-aging components.

[0029] Finally, pre-modified chitosan was prepared by reacting chitosan with diallyl chlorophosphate. Phosphorus and carbon-carbon double bonds were grafted onto the pre-modified chitosan. The introduction of phosphorus can further improve the flame retardant properties of the anti-aging latex material. The carbon-carbon double bonds grafted onto the pre-modified chitosan were reacted with the thiol group on 1H-benzimidazole-2-thiol to prepare modified chitosan. Benzimidazole structures were grafted onto the modified chitosan. Benzimidazole further improves the anti-aging properties of the anti-aging latex material by capturing free radicals and terminating the oxidation chain reaction. Grafting small molecular weight benzimidazole antioxidants onto large molecular weight chitosan also prevents the migration and loss of anti-aging components. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] The butadiene rubber used in the following examples and comparative examples is BR9000; the degree of deacetylation of the chitosan used is 90%, and the weight-average molecular weight is 85 kDa.

[0032] Example 1:

[0033] A method for preparing an anti-aging latex material, the method comprising the following preparation steps:

[0034] (1) Pentaerythritol and vinyl boric acid were added to benzene at a molar ratio of 1:2 to 14 times the mass of pentaerythritol. The mixture was stirred at 300 r / min for 8 h at 78 °C and dried at 60 °C for 10 h under vacuum to obtain pentaerythritol borate monomer. 1,1,3,3,5,5-hexamethyltrisiloxane and pentaerythritol borate monomer were added to toluene at a molar ratio of 1:1.2 to 18 times the mass of pentaerythritol borate monomer. Chloroplatinic acid at a molar ratio of 0.04 times the mass of pentaerythritol borate monomer was added. The mixture was stirred at 100 r / min for 7 h at 70 °C. Toluene was removed by rotary evaporation under reduced pressure. The mixture was washed three times each with anhydrous ethanol and deionized water and dried at 70 °C for 12 h under vacuum to obtain borosilicate composite flame retardant.

[0035] (2) Weigh out lanthanum chloride, 4-ethylene-2-hydroxybenzoic acid and sodium hydroxide in a molar ratio of 1:3:3; mix lanthanum chloride and anhydrous ethanol in a mass ratio of 1:8 to prepare a lanthanum chloride solution; prepare a sodium hydroxide aqueous solution with a concentration of 2 mol / L; mix 4-ethylene-2-hydroxybenzoic acid and anhydrous ethanol in a mass ratio of 1:20, stir at 200 r / min for 20 min at 55℃, add sodium hydroxide aqueous solution dropwise at a uniform rate over 5 min, continue stirring for 50 min after the addition is complete, cool down to 50℃, add lanthanum chloride solution dropwise at a uniform rate over 20 min, continue stirring for 5 h after the addition is complete, adjust the pH of the solution to 6.6 with a 6% sodium hydroxide aqueous solution, let stand at room temperature for 14 h, filter, wash 3 times each with anhydrous ethanol and deionized water, and dry at 36℃ for 24 h under vacuum to obtain an organolanthanum rare earth complex;

[0036] (3) Weigh chitosan, diallyl chlorophosphate, and triethylamine in a mass ratio of 1:2:0.3; mix diallyl chlorophosphate and methanol in a mass ratio of 1:8 to prepare a diallyl chlorophosphate solution; mix chitosan and methanol in a mass ratio of 1:50, stir at 200 r / min for 2 h at room temperature, add triethylamine and mix well, heat to 60℃, and add diallyl chlorophosphate solution dropwise at a uniform rate over 25 min while stirring at 200 r / min. After the addition is complete... The reaction was continued for 8 hours with stirring. The solvent was evaporated, and the mixture was washed three times each with methanol and deionized water. Under vacuum conditions, it was dried at 50°C for 12 hours to obtain pre-modified chitosan. The pre-modified chitosan, 1H-benzimidazole-2-thiol, azobisisobutyronitrile, and N,N-dimethylformamide were mixed evenly in a mass ratio of 1:3:0.1:26. The mixture was stirred at 70°C and 200 r / min for 6 hours with stirring. The solvent was evaporated, and the mixture was washed three times with anhydrous ethanol. Under vacuum conditions, it was dried at 50°C for 12 hours to obtain modified chitosan.

[0037] (4) Weigh out 98 parts of raw butadiene rubber, 20 parts of carbon black (N330), 6 parts of modified chitosan, 4 parts of organic lanthanum rare earth complex, 7 parts of borosilicate composite flame retardant, 3 parts of zinc oxide, 2 parts of stearic acid, 1.3 parts of sulfur, and 1 part of accelerator (TBBS) by mass. Place carbon black (N330), zinc oxide, stearic acid, raw butadiene rubber, and borosilicate composite flame retardant in a mixer and mix at 120°C for 10 minutes. Then, place them in an open mill for plasticizing at 40°C for 2 minutes. Add modified chitosan and organic lanthanum rare earth complex and mix for 6 minutes. Add sulfur and accelerator (TBBS) and mix for 4 minutes. Form a triangular bag and pass through a thin tube 6 times. Discharge the material to obtain a compound. Place the compound at room temperature for 24 hours and vulcanize and press it into sheets in a flat vulcanizing machine. The vulcanization time is 10 minutes and the vulcanization temperature is 160°C to obtain an anti-aging latex material.

[0038] Example 2:

[0039] A method for preparing an anti-aging latex material, the method comprising the following preparation steps:

[0040] (1) Pentaerythritol and vinyl boric acid were added to benzene at a molar ratio of 1:2.1 to 15 times the mass of pentaerythritol. The mixture was stirred at 78°C and 400 r / min for 7.5 h. The mixture was then dried at 65°C under vacuum for 9 h to obtain pentaerythritol borate monomer. 1,1,3,3,5,5-hexamethyltrisiloxane and pentaerythritol borate monomer were added to toluene at a molar ratio of 1:1.3 to 19 times the mass of pentaerythritol borate monomer. Chloroplatinic acid at a molar ratio of 0.05 times the mass of pentaerythritol borate monomer was added. The mixture was stirred at 75°C and 150 r / min for 6.5 h. Toluene was removed by rotary evaporation under reduced pressure. The mixture was washed three times each with anhydrous ethanol and deionized water. The mixture was then dried at 75°C under vacuum for 11 h to obtain borosilicate composite flame retardant.

[0041] (2) Weigh out lanthanum chloride, 4-ethylene-2-hydroxybenzoic acid and sodium hydroxide in a molar ratio of 1:3:3; mix lanthanum chloride and anhydrous ethanol in a mass ratio of 1:9 to prepare a lanthanum chloride solution; prepare a sodium hydroxide aqueous solution with a concentration of 2 mol / L; mix 4-ethylene-2-hydroxybenzoic acid and anhydrous ethanol in a mass ratio of 1:22, stir at 250 r / min for 15 min at 60℃, add sodium hydroxide aqueous solution dropwise at a uniform rate over 5 min, continue stirring for 45 min after the addition is complete, cool down to 50℃, add lanthanum chloride solution dropwise at a uniform rate over 20 min, continue stirring for 4.5 h after the addition is complete, adjust the pH of the solution to 6.8 with a 6% sodium hydroxide aqueous solution, let stand at room temperature for 13 h, filter, wash 3 times each with anhydrous ethanol and deionized water, and dry at 38℃ for 22 h under vacuum to obtain an organolanthanum rare earth complex;

[0042] (3) Weigh chitosan, diallyl chlorophosphate, and triethylamine in a mass ratio of 1:2.5:0.35; mix diallyl chlorophosphate and methanol in a mass ratio of 1:9 to prepare a diallyl chlorophosphate solution; mix chitosan and methanol in a mass ratio of 1:55, stir at 250 r / min for 1.5 h at room temperature, add triethylamine and mix well, heat to 60℃, and add diallyl chlorophosphate solution dropwise at a uniform rate over 25 min while stirring at 250 r / min. After the addition is complete, continue... The reaction was stirred for 7.5 h, the solvent was evaporated, and the mixture was washed three times each with methanol and deionized water. The mixture was then dried at 55 °C for 11 h under vacuum to obtain pre-modified chitosan. The pre-modified chitosan, 1H-benzimidazole-2-thiol, azobisisobutyronitrile, and N,N-dimethylformamide were mixed uniformly at a mass ratio of 1:3.5:0.15:27. The mixture was stirred at 75 °C and 250 r / min for 5.5 h, the solvent was evaporated, and the mixture was washed three times with anhydrous ethanol. The mixture was then dried at 55 °C for 11 h under vacuum to obtain modified chitosan.

[0043] (4) Weigh out 100 parts by weight of butadiene rubber raw rubber, 22 parts of carbon black (N330), 6.5 parts of modified chitosan, 4.5 parts of organolanthanum rare earth complex, 7.5 parts of borosilicate composite flame retardant, 3.5 parts of zinc oxide, 2.2 parts of stearic acid, 1.4 parts of sulfur, and 1.1 parts of accelerator (TBBS); place carbon black (N330), zinc oxide, stearic acid, butadiene rubber raw rubber, and borosilicate composite flame retardant in a mixer and mix at 125°C for 9 minutes. The mixture is then placed in an open mill for plasticizing at 45°C for 1.5 minutes. Modified chitosan and organic lanthanum rare earth complex are added and mixed for 5.5 minutes. Sulfur and accelerator (TBBS) are added and mixed for 3.5 minutes. The mixture is then formed into triangular bags, passed through a thin tube 7 times, and discharged to obtain the compound rubber. The compound rubber is left at room temperature for 24 hours and then vulcanized and pressed into sheets in a flat vulcanizing machine at 10 minutes and 160°C to obtain the anti-aging latex material.

[0044] Example 3:

[0045] A method for preparing an anti-aging latex material, the method comprising the following preparation steps:

[0046] (1) Pentaerythritol and vinyl boric acid were added to benzene at a molar ratio of 1:2.2 to 16 times the mass of pentaerythritol. The mixture was stirred at 78°C and 500 r / min for 7 h. The mixture was then dried at 70°C under vacuum for 8 h to obtain pentaerythritol borate monomer. 1,1,3,3,5,5-hexamethyltrisiloxane and pentaerythritol borate monomer were added to toluene at a molar ratio of 1:1.4 to 20 times the mass of pentaerythritol borate monomer. Chloroplatinic acid was added at a molar ratio of 0.06 times the mass of pentaerythritol borate monomer. The mixture was stirred at 80°C and 200 r / min for 6 h. Toluene was removed by rotary evaporation under reduced pressure. The mixture was washed three times each with anhydrous ethanol and deionized water. The mixture was then dried at 80°C under vacuum for 10 h to obtain borosilicate composite flame retardant.

[0047] (2) Weigh out lanthanum chloride, 4-ethylene-2-hydroxybenzoic acid and sodium hydroxide in a molar ratio of 1:3:3; mix lanthanum chloride and anhydrous ethanol in a mass ratio of 1:10 to prepare a lanthanum chloride solution; prepare a sodium hydroxide aqueous solution with a concentration of 2 mol / L; mix 4-ethylene-2-hydroxybenzoic acid and anhydrous ethanol in a mass ratio of 1:24, stir at 300 r / min for 10 min at 65℃, add sodium hydroxide aqueous solution dropwise at a uniform rate over 5 min, continue stirring for 40 min after the addition is complete, cool down to 50℃, add lanthanum chloride solution dropwise at a uniform rate over 20 min, continue stirring for 4 h after the addition is complete, adjust the pH of the solution to 7 with a 6% sodium hydroxide aqueous solution, let stand at room temperature for 12 h, filter, wash 3 times each with anhydrous ethanol and deionized water, dry at 40℃ for 20 h under vacuum to obtain an organolanthanum rare earth complex;

[0048] (3) Weigh chitosan, diallyl chlorophosphate, and triethylamine in a mass ratio of 1:3:0.4; mix diallyl chlorophosphate and methanol in a mass ratio of 1:10 to prepare a diallyl chlorophosphate solution; mix chitosan and methanol in a mass ratio of 1:60, stir at 300 r / min for 1 h at room temperature, add triethylamine and mix well, heat to 60℃, and add diallyl chlorophosphate solution dropwise at a uniform rate over 25 min while stirring at 300 r / min. The reaction was continued with stirring for 7 hours. The solvent was then evaporated, and the mixture was washed three times each with methanol and deionized water. Under vacuum conditions, it was dried at 60°C for 10 hours to obtain pre-modified chitosan. The pre-modified chitosan, 1H-benzimidazole-2-thiol, azobisisobutyronitrile, and N,N-dimethylformamide were mixed evenly in a mass ratio of 1:4:0.2:28. The mixture was stirred at 80°C and 300 r / min for 5 hours. The solvent was then evaporated, and the mixture was washed three times with anhydrous ethanol. Under vacuum conditions, it was dried at 60°C for 10 hours to obtain modified chitosan.

[0049] (4) Weigh out 102 parts by weight of butadiene rubber raw rubber, 24 parts of carbon black (N330), 7 parts of modified chitosan, 5 parts of organolanthanum rare earth complex, 8 parts of borosilicate composite flame retardant, 4 parts of zinc oxide, 2.4 parts of stearic acid, 1.5 parts of sulfur, and 1.2 parts of accelerator (TBBS); place carbon black (N330), zinc oxide, stearic acid, butadiene rubber raw rubber, and borosilicate composite flame retardant in a mixer and mix at 130°C for 8 minutes. The mixture is then placed in an open mill for plasticizing at 50°C for 1 minute. Modified chitosan and organic lanthanum rare earth complex are added and mixed for 5 minutes. Sulfur and accelerator (TBBS) are added and mixed for 3 minutes. The mixture is then formed into triangular bags and passed through a thin tube 8 times before being discharged to obtain the compound rubber. The compound rubber is left at room temperature for 24 hours and then vulcanized and pressed into sheets in a flat vulcanizing machine at 10 minutes and 160°C to obtain the anti-aging latex material.

[0050] Comparative Example 1:

[0051] The preparation method of the anti-aging latex material in Comparative Example 1 differs from that in Example 2 in that step (1) is omitted, and step (4) is modified as follows: Weigh 100 parts of butadiene rubber raw rubber, 22 parts of carbon black (N330), 6.5 parts of modified chitosan, 4.5 parts of organolanthanum rare earth complex, 3.5 parts of zinc oxide, 2.2 parts of stearic acid, 1.4 parts of sulfur, and 1.1 parts of accelerator (TBBS) by mass; place carbon black (N330), zinc oxide, stearic acid, and butadiene rubber raw rubber in a dense container. In a mill, the mixture is internally mixed at 125°C for 9 minutes, then placed in an open mill for plasticizing at 45°C for 1.5 minutes. Modified chitosan and an organolanthanum rare earth complex are added, and the mixture is kneaded for 5.5 minutes. Sulfur and an accelerator (TBBS) are added, and the mixture is kneaded for 3.5 minutes. The mixture is then formed into triangular slabs, passed through a thin tube 7 times, and discharged to obtain a compound rubber. The compound rubber is left at room temperature for 24 hours, then vulcanized and pressed into sheets in a flat vulcanizing machine for 10 minutes at a vulcanization temperature of 160°C to obtain an anti-aging latex material. The remaining steps are the same as in Example 2.

[0052] Comparative Example 2:

[0053] The preparation method of the anti-aging latex material in Comparative Example 2 differs from that in Example 2 in that step (2) is omitted, and step (4) is modified as follows: Weigh 100 parts of butadiene rubber raw rubber, 22 parts of carbon black (N330), 6.5 parts of modified chitosan, 7.5 parts of borosilicate composite flame retardant, 3.5 parts of zinc oxide, 2.2 parts of stearic acid, 1.4 parts of sulfur, and 1.1 parts of accelerator (TBBS) by mass; and mix carbon black (N330), zinc oxide, stearic acid, butadiene rubber raw rubber, borosilicate composite flame retardant, zinc oxide, stearic acid, and modified chitosan with the following ingredients: The silicone composite flame retardant was placed in a Banbury mixer and mixed at 125°C for 9 minutes. Then, it was placed in a two-roll mill for plasticizing at 45°C for 1.5 minutes. Modified chitosan was added and mixed for 5.5 minutes. Sulfur and an accelerator (TBBS) were added and mixed for 3.5 minutes. The mixture was then formed into triangular slabs, passed through a thin tube 7 times, and discharged to obtain a compound rubber. The compound rubber was left at room temperature for 24 hours and then vulcanized and pressed into sheets in a flat vulcanizing machine for 10 minutes at 160°C to obtain an anti-aging latex material. The remaining steps were the same as in Example 2.

[0054] Comparative Example 3:

[0055] The preparation method of the anti-aging latex material in Comparative Example 3 differs from that in Example 2 only in step (3). Step (3) is modified as follows: chitosan, diallyl chlorophosphate, and triethylamine are weighed in a mass ratio of 1:2.5:0.35; diallyl chlorophosphate and methanol are mixed evenly in a mass ratio of 1:9 to prepare a diallyl chlorophosphate solution; chitosan and methanol are mixed evenly in a mass ratio of 1:55, stirred at 250 r / min for 1.5 h at room temperature, triethylamine is added and mixed evenly, the temperature is raised to 60 °C, and diallyl chlorophosphate solution is added dropwise at a uniform rate over 25 min while stirring at 250 r / min. After the addition is complete, the reaction is continued to be stirred for 7.5 h, the solvent is evaporated, and the mixture is washed 3 times each with methanol and deionized water. The mixture is then dried at 55 °C for 11 h under vacuum to obtain modified chitosan. The remaining steps are the same as in Example 2.

[0056] Comparative Example 4:

[0057] The preparation method of the anti-aging latex material in Comparative Example 4 differs from that in Example 2 in that step (3) is omitted, and step (4) is modified as follows: Weigh 100 parts of butadiene rubber raw rubber, 22 parts of carbon black (N330), 6.5 parts of chitosan, 4.5 parts of organic lanthanum rare earth complex, 7.5 parts of borosilicate composite flame retardant, 3.5 parts of zinc oxide, 2.2 parts of stearic acid, 1.4 parts of sulfur, and 1.1 parts of accelerator (TBBS) by mass; and mix carbon black (N330), zinc oxide, stearic acid, butadiene rubber raw rubber, The borosilicate composite flame retardant was placed in a Banbury mixer and mixed at 125°C for 9 minutes. It was then placed in a two-roll mill for plasticizing at 45°C for 1.5 minutes. Chitosan and an organolanthanum rare earth complex were added and mixed for 5.5 minutes. Sulfur and an accelerator (TBBS) were added and mixed for 3.5 minutes. The mixture was then formed into triangular slabs, passed through a thin tube 7 times, and discharged to obtain a compound rubber. The compound rubber was left at room temperature for 24 hours and then vulcanized and pressed into sheets in a flat vulcanizing machine for 10 minutes at 160°C to obtain an anti-aging latex material. The remaining steps were the same as in Example 2.

[0058] Test Example 1

[0059] Anti-aging performance test

[0060] Test method: In accordance with GB / T3512-2014, the GT-7014-E type thermal aging oven was used to conduct thermo-oxidative aging tests on the examples and comparative examples. The test specimens were clamped with fixtures and suspended in the aging oven. The aging conditions were 100℃×120h. Tensile strength, elongation at break, and tear strength were measured, and the performance retention rate of these parameters was calculated. The performance retention rate was calculated using the formula: (parameter after aging / parameter before aging)×100%. The results are shown in Table 1.

[0061] Table 1

[0062] Tensile strength retention rate (%) Elongation at break retention rate (%) Tear strength retention rate (%) Example 1 89.3 71.6 93.7 Example 2 90.6 73.8 94.1 Example 3 90.1 72.3 94.5 Comparative Example 1 86.2 68.9 90.3 Comparative Example 2 74.7 61.7 82.7 Comparative Example 3 77.2 64.2 85.8 Comparative Example 4 76.7 63.7 84.1

[0063] A comparison of the experimental data of Examples 1-3 and Comparative Examples 1-5 in Table 1 shows that the anti-aging latex material prepared by the present invention has good anti-aging properties.

[0064] By comparison, the tensile strength retention rate, elongation at break retention rate, and tear strength retention rate of Examples 1-3 are all greater than those of Comparative Example 2. This indicates that the organic lanthanum rare earth complex was prepared by reacting lanthanum chloride and 4-ethylene-2-hydroxybenzoic acid. 4-ethylene-2-hydroxybenzoic acid contains a carboxylic acid group, and the lanthanum ion of the metal undergoes a coordination effect with the carboxylic acid group to form an organic lanthanum rare earth complex. Rubber aging is caused by the presence of a large number of unsaturated double bonds in the rubber molecular chain, which readily react with oxygen in the air. The large number of empty orbitals of rare earth elements have a strong ability to bind with free radicals, which can terminate the chain reaction, effectively inhibit oxidation, and improve the anti-aging performance of anti-aging latex materials.

[0065] By comparison, the tensile strength retention rate, elongation at break retention rate, and tear strength retention rate of Examples 1-3 were all greater than those of Comparative Examples 3-4. This indicates that pre-modified chitosan was prepared by reacting chitosan with diallyl chlorophosphate, and carbon-carbon double bonds were grafted onto the pre-modified chitosan. The carbon-carbon double bonds grafted onto the pre-modified chitosan underwent an addition reaction with the thiol group on 1H-benzimidazole-2-thiol to prepare modified chitosan. Benzimidazole structures were grafted onto the modified chitosan. Benzimidazole, by capturing free radicals, terminated the oxidation chain reaction, further improving the anti-aging performance of the anti-aging latex material.

[0066] Test Example 2

[0067] Flame retardant performance testing

[0068] Test method: The test was conducted using a limiting oxygen index analyzer. Standard: GB / T10707-2008. Sample dimensions: 120 mm long, 6.5 mm wide, and 3 mm thick. Results are shown in Table 2.

[0069] Table 2

[0070] Limiting oxygen index (%) Limiting oxygen index (%) Example 1 30.7 Comparative Example 1 24.8 Example 2 31.8 Comparative Example 2 29.6 Example 3 31.2 Comparative Example 3 30.1 Comparative Example 4 26.2

[0071] A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-5 in Table 2 reveals that the anti-aging latex material prepared by this invention has good flame retardant properties.

[0072] By comparison, the limiting oxygen index of Examples 1-3 is greater than that of Comparative Example 1, indicating that pentaerythritol borate ester monomer is prepared by reacting pentaerythritol and vinyl boric acid; the Si-H bond on 1,1,3,3,5,5-hexamethyltrisiloxane is subjected to hydrosilylation reaction with the carbon-carbon double bond on the pentaerythritol borate ester monomer to polymerize and obtain borosilicate composite flame retardant; the reaction ensures that the pentaerythritol borate ester monomer is in excess, and the obtained borosilicate composite flame retardant is end-capped by carbon-carbon double bonds. The addition of borosilicate composite flame retardant can improve the flame retardant performance of anti-aging latex materials.

[0073] By comparison, the limiting oxygen index of Examples 1-3 is greater than that of Comparative Example 4, indicating that pre-modified chitosan is prepared by reacting chitosan with diallyl chlorophosphate, and phosphorus is grafted onto the pre-modified chitosan; the introduction of phosphorus can further improve the flame retardant properties of anti-aging latex materials.

[0074] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An anti-aging latex material, characterized in that, By weight, it includes: 98-102 parts butadiene rubber raw rubber, 20-24 parts carbon black, 6-7 parts modified chitosan, 4-5 parts organolanthanum rare earth complex, 7-8 parts borosilicate composite flame retardant, 3-4 parts zinc oxide, 2-2.4 parts stearic acid, 1.3-1.5 parts sulfur, and 1-1.2 parts accelerator; The modified chitosan was prepared by reacting chitosan sequentially with diallyl chlorophosphate and 1H-benzimidazole-2-thiol; The organolanthanum rare earth complex is prepared by reacting lanthanum chloride and 4-ethylene-2-hydroxybenzoic acid. The borosilicate composite flame retardant is prepared by reacting 1,1,3,3,5,5-hexamethyltrisiloxane and pentaerythritol borate monomers. The pentaerythritol borate monomer is prepared by reacting pentaerythritol and vinylboric acid.

2. A method for preparing an anti-aging latex material, characterized in that, The preparation method of the anti-aging latex material includes the following preparation steps: (1) 1,1,3,3,5,5-hexamethyltrisiloxane and pentaerythritol borate monomers were added to toluene, and 0.04 to 0.06 times the mass of pentaerythritol borate monomers of chloroplatinic acid were added. The mixture was reacted at 70 to 80 °C for 6 to 7 h to obtain borosilicate composite flame retardant. (2) Lanthanum chloride and anhydrous ethanol were mixed evenly to prepare a lanthanum chloride solution; sodium hydroxide was prepared into a 2 mol / L sodium hydroxide aqueous solution; 4-ethylene-2-hydroxybenzoic acid and anhydrous ethanol were mixed evenly and stirred at 55~65℃ for 10~20 min, sodium hydroxide aqueous solution was added dropwise, and the reaction was continued to be stirred for 40~50 min, the temperature was lowered to 50℃, lanthanum chloride solution was added dropwise, and the reaction was continued to be stirred for 4~5 h, the pH of the solution was adjusted to 6.6~7, and the solution was allowed to stand at room temperature for 12~14 h, filtered, washed and dried to obtain the organolanthanum rare earth complex; (3) Mix pre-modified chitosan, 1H-benzimidazole-2-thiol, azobisisobutyronitrile, and N,N-dimethylformamide evenly, and stir and react at 70~80℃ for 5~6h to obtain modified chitosan. (4) Carbon black, zinc oxide, stearic acid, cis-butadiene rubber raw rubber and borosilicate composite flame retardant are placed in a mixer and mixed at 120~130℃ for 8~10 minutes. Then, they are placed in an open mill for plasticizing at 40~50℃ for 1~2 minutes. Modified chitosan and organic lanthanum rare earth complex are added and mixed for 5~6 minutes. Sulfur and accelerator are added and mixed for 3~4 minutes. The mixture is then formed into triangular bags and discharged through a thin tube to obtain a compound rubber. The compound rubber is placed at room temperature for 24 hours and then vulcanized and pressed into sheets in a flat vulcanizing machine to obtain an anti-aging latex material.

3. The method for preparing an anti-aging latex material according to claim 2, characterized in that, The method for preparing the pentaerythritol borate monomer in step (1) is as follows: pentaerythritol and vinyl boric acid are added to benzene in a molar ratio of 1:(2~2.2), reacted at 78°C for 7~8h, and dried under vacuum to obtain the pentaerythritol borate monomer.

4. The method for preparing an anti-aging latex material according to claim 2, characterized in that, The molar ratio of 1,1,3,3,5,5-hexamethyltrisiloxane and pentaerythritol borate monomer in step (1) is 1:(1.2~1.4).

5. The method for preparing an anti-aging latex material according to claim 2, characterized in that, The molar ratio of lanthanum chloride, 4-ethylene-2-hydroxybenzoic acid, and sodium hydroxide in step (2) is 1:3:

3.

6. The method for preparing an anti-aging latex material according to claim 2, characterized in that, The preparation method of the pre-modified chitosan in step (3) is as follows: mix diallyl chlorophosphate and methanol evenly to prepare diallyl chlorophosphate solution; mix chitosan and methanol evenly, stir at room temperature for 1-2 hours, add triethylamine and mix evenly, heat to 60°C, add diallyl chlorophosphate solution dropwise, and continue stirring and reacting for 7-8 hours after the addition is complete to obtain pre-modified chitosan.

7. The method for preparing an anti-aging latex material according to claim 6, characterized in that, The mass ratio of chitosan, diallyl chlorophosphate, and triethylamine is 1:(2~3):(0.3~0.4).

8. The method for preparing an anti-aging latex material according to claim 2, characterized in that, The amounts of butadiene rubber raw rubber, carbon black, modified chitosan, organolanthanum rare earth complex, borosilicate composite flame retardant, zinc oxide, stearic acid, sulfur, and accelerator in step (4) are as follows: by mass parts, 98-102 parts of butadiene rubber raw rubber, 20-24 parts of carbon black, 6-7 parts of modified chitosan, 4-5 parts of organolanthanum rare earth complex, 7-8 parts of borosilicate composite flame retardant, 3-4 parts of zinc oxide, 2-2.4 parts of stearic acid, 1.3-1.5 parts of sulfur, and 1-1.2 parts of accelerator.

9. The method for preparing an anti-aging latex material according to claim 2, characterized in that, The vulcanization time for the vulcanized tablets in step (4) is 10 min, and the vulcanization temperature is 160℃.