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CN-122011009-A - Preparation process of sulfur-containing silane coupling agent

CN122011009ACN 122011009 ACN122011009 ACN 122011009ACN-122011009-A

Abstract

The invention provides a preparation process of a sulfur-containing silane coupling agent, which is characterized in that through an aqueous solution system, chloropropyl triethoxy silane is added while amino or sulfhydryl-containing siloxane is added, amino in the aminosilane provides an alkaline microenvironment, polysulfide anions are activated, meanwhile, na + can be complexed to promote phase transfer, the reaction process is improved, the reaction time is shortened, the final chromaticity of a product can be effectively reduced, sulfhydryl in the sulfhydryl silane can be directly exchanged with polysulfide to generate mixed sulfide, meanwhile, the sulfhydryl silane can be used as a chain transfer agent, the length of a sulfur chain is controlled, the sulfur chain length and the average sulfur content of a product Si69 are more stable, and the sulfur-containing silane coupling agent with stable sulfur content can be obtained only through simple liquid separation and sedimentation decolorization.

Inventors

  • WU JUNCHEN
  • JIANG LUO
  • JIANG WEIHUA
  • GONG ZHILIANG
  • WU XIANGHU
  • Tang Wangming
  • XU JUNJIAN

Assignees

  • 湖北和远新材料有限公司

Dates

Publication Date
20260512
Application Date
20260130

Claims (10)

  1. 1. The preparation process of the sulfur-containing silane coupling agent is characterized by comprising the following steps: s1, obtaining or preparing a sodium tetrasulfide aqueous solution; S2, adding an alkaline buffer reagent and a phase transfer catalyst into the sodium tetrasulfide aqueous solution under stirring, and heating to a temperature close to the synthesis reaction temperature; S3, dropwise adding chloropropyl triethoxysilane and amino-containing and/or mercapto-containing siloxane into the solution obtained in the step S2 under stirring, carrying out heat preservation reaction after the addition, standing, separating liquid and removing a water layer, and carrying out sedimentation and decoloration on an organic layer to obtain the sulfur-containing silane coupling agent.
  2. 2. The preparation process according to claim 1, wherein in step S3, the addition amount of the amino-and/or mercapto-containing siloxane is 1-5% of the mass of chloropropyl triethoxysilane; And/or the amino-containing siloxane is at least one selected from aminopropyl triethoxysilane and aminopropyl methyldiethoxysilane; and/or the sulfhydryl-containing siloxane is selected from at least one of mercaptopropyl triethoxysilane and mercaptopropyl methyl triethoxysilane.
  3. 3. The process according to claim 1, wherein in step S2, the phase transfer catalyst is tetrabutylammonium bromide.
  4. 4. The process according to claim 1, wherein in step S2, the temperature is controlled to be 70-80 ℃ and/or the stirring time is 10-20min.
  5. 5. The preparation process according to claim 1, wherein in step S3, the incubation temperature is 75-80 ℃ and the reaction time is 1.5-2h.
  6. 6. The process according to claim 1, wherein in step S3, the dropping rate is 4-25g/min.
  7. 7. The preparation process according to claim 1, wherein in step S1, the sodium tetrasulfide is obtained by heating sodium sulfide and sulfur powder in water.
  8. 8. The preparation process according to claim 7, wherein the mass ratio of the sulfur, sodium sulfide, alkaline buffer agent, phase transfer catalyst, chloropropyl triethoxysilane to the water used in the step S1 is 1 (1.35-1.5): (0.3-0.6): (0.05-0.075): (5-5.5): (4-8).
  9. 9. The process according to claim 7, wherein in step S1, the reaction temperature is 50-60 ℃ and the reaction time is 40-60min.
  10. 10. The process according to claim 1, wherein in step S3, the decoloring process uses a cation exchange resin.

Description

Preparation process of sulfur-containing silane coupling agent Technical Field The invention relates to the technical field of silane coupling agents, in particular to a preparation process of a sulfur-containing silane coupling agent. Background Sulfur-containing silane is a conventional silane coupling agent, and is mainly used as an additive of tire rubber for improving the performances of tearing resistance, abrasion resistance, wet grip and the like of tires. The sulfur-containing silanes currently most used are bis- (triethoxysilylpropyl) polysulfides, mainly bis- (triethoxysilylpropyl) disulfide and bis- (triethoxysilylpropyl) tetrasulfide, in amounts of more than 90% of the total sulfur-containing silane. Bis- (triethoxysilylpropyl) tetrasulfide (trade name Si 69) plays an irreplaceable role as a highly effective multifunctional silane coupling agent in the rubber industry, especially in green tire manufacturing. The triethoxy silicon group in the molecular structure can react with silicon hydroxyl on the surface of white carbon black, while the tetrasulfide bond participates in the rubber vulcanization process to form a molecular bridge of inorganic filler-coupling agent-rubber. The unique structure solves the core problem of poor dispersibility of the white carbon black in rubber, reduces the rolling resistance of the tire by 30%, improves the wear resistance by 50%, and simultaneously remarkably improves the wet skid resistance. The global green tire market expands at an annual growth rate of 20%, driving the Si69 demand to continue to rise. At present, the main technical routes in industry all have obvious bottlenecks: 1. Sodium hydrosulfide route Sodium hydrosulfide (NaHS), sulfur and gamma-chloropropyl triethoxysilane (gamma 2) are adopted to react in ethanol 2(C2H5O)3Si(CH2)3Cl + Na2S4 → [(C2H5O)3Si(CH2)3]2S4 + 2NaCl The fatal defect of the technology is that highly toxic gas hydrogen sulfide (H 2 S) is continuously released in the reaction process, and an alkali liquor absorption tower is required to be equipped for treating tail gas. The sulfur-containing waste liquid produced by each ton of the product is 0.8-1.2 ton, the COD is as high as more than 5000 mg/L, and the treatment cost accounts for 15% of the production cost. In addition, residual mercaptan impurities in the product lead to darkening of colour (APHA > 200) during storage, limiting its use in light coloured rubber articles. 2. Anhydrous sodium sulfide route Anhydrous Na 2 S and sulfur are used for preparing sodium polysulfide in absolute ethyl alcohol, and then the sodium polysulfide reacts with gamma 2: Na2S + 3S → Na2S4 Na2S4 + 2Cl(CH2) 3Si(OC2H5) 3 → Si69 + 2NaCl Although this method avoids the production of H 2 S, the sensitivity of the raw material becomes a new problem. Anhydrous sodium sulfide is extremely susceptible to moisture absorption and oxidation (weight gain rate in air > 5%/h), and may cause spontaneous combustion explosion risks during operation. Meanwhile, the whole process is protected by nitrogen, the reaction time is 8-12 hours, and the energy consumption is 40% higher than other processes. 3. Sodium ethoxide-sodium hydrosulfide route Adopts metal sodium, ethanol, sodium hydrosulfide, sulfur and gamma 2 as raw materials, and is synthesized by two steps: 2C2H5OH + 2Na → 2C2H5ONa + H2 C2H5ONa + NaHS →C2H5OH + Na2S Na2S + 3S → Na2S4 although the ethanol is recycled by the method, the use of the sodium metal brings high-risk operation hidden trouble. The reaction of the metallic sodium and the ethanol releases heat severely (delta H= -184 kJ/mol), special temperature control equipment is needed, the residual sodium particles can cause fire, and the actual production accident rate reaches 0.3 times/kiloton. Comprehensive existing technology, industry faces four technical bottlenecks: the solvent dependence and the safety risk are that the dosage of the organic solvents such as ethanol, diethyl ether and the like reaches 300-500 kg/ton of the product, the cost is increased (the solvent accounts for 35 percent of the cost of the raw materials), and the VOC emission exceeds standard (> 120 ppm) and the explosion risk is caused. The pollution of the by-product, namely H 2 S waste gas, salt-containing waste water (8-12 t/ton product) and heavy metal waste residue, and the pollution is three-fold, and the terminal treatment cost accounts for more than 25% of the total cost. The product quality has the defects that the product of the traditional process contains the impurities (more than 4.0 percent) such as trithiocarbonate, the heating decrement is more than 2.5 percent, the storage period is more than 3 months, the color degree is increased to APHA (amorphous polyethylene glycol) 150, and the requirement of high-end rubber products can not be met. The reaction efficiency is low, the batch reaction time is long (5-9 hours), the gamma 2 conversion rate is less than 90%, the sulfur is unevenly distributed (S4 content