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CN-121991352-A - Preparation method and application of polysulfide polymer

CN121991352ACN 121991352 ACN121991352 ACN 121991352ACN-121991352-A

Abstract

The invention provides a preparation method and application of a polysulfide polymer. The preparation method comprises the steps of mixing a dichloro intermediate and sodium polysulfide aqueous solution, and carrying out polycondensation reaction in a formed mixed system to prepare the polysulfide polymer, wherein an organic solvent exists in the mixed system, and the organic solvent is selected from C6-C9 aromatic hydrocarbon. The preparation method can realize rapid and efficient separation of the salt after the polycondensation reaction, thereby improving the quality of the liquid polysulfide rubber obtained by cracking the polysulfide polymer and greatly improving the production efficiency of a production device.

Inventors

  • HAN KAI

Assignees

  • 北京诺维新材科技有限公司

Dates

Publication Date
20260508
Application Date
20241030

Claims (10)

  1. 1. A preparation method of a polysulfide polymer is characterized by comprising the steps of mixing a dichloro intermediate and a sodium polysulfide aqueous solution, and carrying out polycondensation reaction in a formed mixed system to prepare the polysulfide polymer, and the preparation method is characterized in that an organic solvent is present in the mixed system and is selected from C6-C9 aromatic hydrocarbons.
  2. 2. The method according to claim 1, wherein after the polycondensation reaction is completed, the polysulfide polymer is contained in an oil phase and a water phase obtained by standing and phase separation. Preferably, after the polycondensation reaction is completed, standing still for phase separation, wherein the upper layer is an oil phase comprising polysulfide polymer, and the lower layer is an aqueous phase comprising inorganic salt. Preferably, the preparation method further comprises collecting the oil phase to obtain an organic solution of the polysulfide polymer.
  3. 3. The preparation method according to claim 1 or 2, wherein the dichloro intermediate has the structure Cl-R-Cl, R being selected from alkylene, -R 11 -O-R 12 -, or-R 2 -O-R 3 -O-R 2 -; Wherein R 11 and R 12 are the same or different and are independently selected from C1-C5 alkylene; R 2 and R 3 are identical or different and are selected independently of one another from C1-C5-alkylene.
  4. 4. A method according to any one of claims 1 to 3, wherein the volume ratio of the organic solvent and the aqueous sodium polysulfide solution in the mixed system is 1-2:1.
  5. 5. The method according to any one of claims 1 to 4, wherein the sodium polysulfide aqueous solution comprises sodium polysulfide and water, wherein the mass fraction of sodium polysulfide is 1 to 50wt%. Preferably, the sodium polysulfide has a sulfur index of 1 to 5. Preferably, the molar ratio of sodium polysulfide to dichloro intermediate is 1-1.4:1.
  6. 6. The process according to any one of claims 1 to 5, wherein the polycondensation reaction is carried out at a temperature of 60 to 120 ℃. Preferably, the polycondensation reaction time is 2 to 6 hours. Preferably, in the preparation method, during the polycondensation reaction, the dichloro intermediate is added dropwise to the sodium polysulfide aqueous solution in the presence of an organic solvent.
  7. 7. A polysulfide polymer, characterized in that it is obtained by the preparation process as claimed in any one of claims 1 to 6.
  8. 8. The polysulfide polymer of claim 7, wherein the polysulfide polymer has a weight average molecular weight of 20000 to 100000.
  9. 9. The polysulfide polymer of claim 7 or 8, wherein the organic solution of the polysulfide polymer has a pH of no more than 8.5. Preferably, the solid content in the organic solution of the polysulfide polymer is not more than 30wt%.
  10. 10. Use of the polysulfide polymer of any one of claims 7-9 in the preparation of liquid polysulfide rubber.

Description

Preparation method and application of polysulfide polymer Technical Field The invention belongs to the technical field of polymer preparation, and relates to a preparation method and application of a polysulfide polymer. Background The liquid polysulfide rubber is easy to glue, and the product after vulcanization and solidification has excellent oil resistance, ozone resistance and low temperature performance, so that the liquid polysulfide rubber is widely applied to the fields of aircraft oil phase sealants, adhesives of rocket propellants, buildings, automobiles, railways, hollow glass, ships and the like. The production method of the liquid polysulfide rubber comprises the steps of carrying out polycondensation reaction on a sodium polysulfide aqueous solution and a dichloro intermediate in a water phase with a dispersing agent to obtain polysulfide polymer emulsion, washing the emulsion for 3-4 times, removing excessive inorganic salts such as sodium polysulfide and the like until the washed latex is neutral, reacting the washed polysulfide polymer with sodium hydrosulfide and sodium sulfite to obtain a cracking product, and acidifying the cracking product to obtain the liquid polysulfide rubber. The emulsion obtained by polycondensation reaction needs to be washed to remove unreacted inorganic salts such as sodium polysulfide and the like before the next reaction, and because the emulsion contains an emulsifying agent, particles of polysulfide polymer are tiny and about 50 mu m, water and latex phase separation is difficult after the emulsion is added with washing water, and the separated water phase is at the upper layer, the water content in the lower latex layer still exceeds 65wt% after standing for 12 hours by prolonging standing time, and meanwhile, the operation difficulty is increased in the production process of the upper layer by the separated water phase. The prior art discloses the addition of flocculants to emulsions, but the disadvantage of longer separation times is still present, and the risk of the cracking reaction being difficult to carry out is increased by the addition of polysulfide polymerization aggregates in the emulsion, and the presence of flocculants in the product, which can suspend as insoluble matter in the final liquid polysulfide rubber product, affecting the quality of the product. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a preparation method of a polysulfide polymer, which can realize rapid and efficient separation of salt after polycondensation reaction, thereby improving the quality of liquid polysulfide rubber obtained by cracking the polysulfide polymer and greatly improving the production efficiency of a production device. Specifically, the technical scheme of the invention is as follows: A preparation method of a polysulfide polymer comprises the steps of mixing a dichloro intermediate and a sodium polysulfide aqueous solution, and carrying out polycondensation reaction in a formed mixed system to prepare the polysulfide polymer, wherein an organic solvent exists in the mixed system, and the organic solvent is selected from C6-C9 aromatic hydrocarbon. According to an embodiment of the invention, after the polycondensation reaction is finished, the oil phase and the water phase are obtained by standing and phase separation, and the polysulfide polymer is included in the oil phase. Specifically, after the polycondensation reaction is finished, standing for phase separation, wherein the upper layer is an oil phase comprising polysulfide polymer, and the lower layer is a water phase comprising inorganic salt. According to an embodiment of the invention, the preparation method further comprises collecting the oil phase to obtain an organic solution of the polysulfide polymer. Preferably, the organic solution of the polysulfide polymer may optionally be further washed with water to obtain an organic solution of the polysulfide polymer free of inorganic salts. According to an embodiment of the invention, the aqueous phase contains inorganic salts in a concentration of 20-40% wt. Further, the inorganic salts include unreacted sodium polysulfide, sodium chloride byproduct, and the like. According to an embodiment of the invention, the dichloro intermediate has the structure Cl-R-Cl, R being selected from alkylene (for example C1-C5 alkylene), -R 11-O-R12 -, or-R 2-O-R3-O-R2 -; Wherein R 11 and R 12 are the same or different and are independently selected from C1-C5 alkylene (e.g., methylene, ethylene, propylene); R 2 and R 3 are identical or different and are selected independently of one another from C1-C5-alkylene (e.g.methylene, ethylene). Illustratively, the dichloro intermediate is dichloroethyl formal, or bis (2-chloroethoxy) methane. Specifically, the dichloroethylformal can be prepared from chloroethanol and paraformaldehyde according to known methods. According to an embodiment of the present invention, t