CN-121757807-B - Method for improving dispersibility and thermal stability of insoluble sulfur

Abstract

The invention discloses a method for improving the dispersibility and the thermal stability of insoluble sulfur, and belongs to the technical field of sulfur processing and production. The technical scheme includes that 1) naphthenic oil, a dispersing agent, a stabilizing agent and a compatibilizer are mixed to obtain a mixed material, wherein the dispersing agent is one or more of dithiodibenzothiazyl, zinc stearate, dioctyl phthalate, polyethylene glycol monolaurate, oleyl alcohol and fatty alcohol polyoxyethylene ether, the compatibilizer is one or more of ethylene propylene diene monomer, EVA resin and liquid butadiene rubber, and 2) the mixed material is mixed with an oil-free insoluble sulfur semi-finished product to be subjected to oil-filling treatment to obtain insoluble sulfur. The method provided by the invention ensures that the prepared insoluble sulfur has good dispersibility and thermal stability, and the process flow is simple and feasible, thereby being beneficial to improving the production efficiency.

Inventors

• Ren dongcheng
• Shang Yunyun
• SU KAIMIN
• WU BINGHUI
• YANG HUIHUI
• ZHAO LIWEI
• WANG CHONG
• WANG QIBING
• GUO YINGJIE
• LIU FANGYUAN
• XU LUYI

Assignees

• 山东海科创新研究院有限公司

Dates

Publication Date

20260505

Application Date

20260228

Claims (6)

1. 1. A method for improving the dispersibility and thermal stability of insoluble sulfur, comprising the steps of: 1) Mixing naphthenic oil, a dispersing agent, a stabilizing agent and a compatibilizer to obtain a mixed material; the dispersing agent is one or more of dithiodibenzothiazyl, zinc stearate, dioctyl phthalate, polyethylene glycol monolaurate, oleyl alcohol and fatty alcohol polyoxyethylene ether; the compatibilizer is one or more of ethylene propylene diene monomer rubber, EVA resin and liquid butadiene rubber; the stabilizer comprises one or more of methyl styrene, pinene and hydrobromic acid; The addition amount of the naphthenic oil is 18-25% of the mass of the non-oil-filled insoluble sulfur semi-finished product; the addition amount of the dispersing agent is 0.1-5% of the mass of the non-oil-filled insoluble sulfur semi-finished product; The addition amount of the stabilizer is 0.1-5% of the mass of the non-oil-filled insoluble sulfur semi-finished product; the addition amount of the compatibilizer is 0.1-5% of the mass of the non-oil-filled insoluble sulfur semi-finished product; 2) Mixing the mixed material with an insoluble sulfur semi-finished product which is not filled with oil to carry out oil filling treatment to obtain insoluble sulfur; And step 1), adding an antistatic agent before mixing, wherein the antistatic agent comprises one or more of sodium dodecyl benzene sulfonate and glyceryl monostearate, and the addition amount of the antistatic agent is 0.3-3% of the mass of the non-oil-filled insoluble sulfur semi-finished product.
2. 2. The method for improving the dispersibility and the thermal stability of insoluble sulfur according to claim 1, wherein the addition amount of the dispersing agent is 0.3-3% of the mass of the non-oil-filled insoluble sulfur semi-finished product.
3. 3. The method for improving the dispersibility and the thermal stability of insoluble sulfur according to claim 1, wherein the addition amount of the stabilizer is 0.3-3% of the mass of the non-oil-filled insoluble sulfur semi-finished product.
4. 4. The method for improving the dispersibility and the thermal stability of insoluble sulfur according to claim 1, wherein the addition amount of the compatibilizer is 0.3-3% of the mass of the semi-finished product of the insoluble sulfur which is not filled with oil.
5. 5. The method for improving the dispersibility and the thermal stability of insoluble sulfur according to claim 1, wherein the semi-finished product of the insoluble sulfur which is not filled with oil is prepared by the following method: a. gasifying raw material liquid sulfur at a high temperature, and performing CS 2 quenching synthesis on the obtained gasified product at 60 ℃ to obtain an insoluble sulfur pre-product; b. And (3) curing, refining, centrifuging, drying, crushing and sieving the insoluble sulfur pre-product in sequence to obtain the insoluble sulfur without oil filling.
6. 6. The method for improving the dispersibility and the thermal stability of insoluble sulfur according to claim 1, wherein the oil-filled treatment in the step 2) is followed by classification screening, and the screened particle size is 30-150 μm.

Description

Method for improving dispersibility and thermal stability of insoluble sulfur Technical Field The invention belongs to the technical field of sulfur processing and production, and particularly relates to a method for improving dispersibility and thermal stability of insoluble sulfur. Background The insoluble sulfur is one kind of amorphous polymer, and is insoluble in common solvent, carbon disulfide, etc. and may be used mainly as rubber vulcanizing agent in tyre industry, including tyre tread, tyre side, etc. The advantages are avoiding frosting (surface whitening) and improving the heat resistance, wear resistance and ageing resistance of the rubber product. The insoluble sulfur synthesizing process includes batch process and continuous process, and the basic production process includes the steps of smelting sulfur, gasifying sulfur, heating, quenching, solidification, extraction, filtering, drying, sieving, oil filling, etc. The batch process has high cost and complicated operation, and the synthesized sample is massive large particles. The sulfur raw material can be recycled in the continuous process, the cost is low, the synthesized sample is micron spherical fine powder (the particle size is usually 10-20 mu m), but the product prepared by the continuous process has large specific surface area and high surface energy, is easy to form hard agglomerates, has poor dispersion performance in rubber and is difficult to split in a matrix. And the dispersibility of the product affects the mechanical and wear-resisting properties of the rubber product. The main factors influencing the dispersibility of insoluble sulfur include particle size, particle shape, particle uniformity, matching of particle surface polarity and matrix (such as rubber), oil filling amount, mixing process and the like. The insoluble sulfur is a linear amorphous polymer (polymerization degree is 200-3000) of sulfur, is in an unstable state in thermodynamics, is easy to undergo depolymerization reaction at high temperature and is converted into annular soluble sulfur (S 8), and the poor thermal stability of the product can directly cause the problems of rubber vulcanization failure, product performance degradation, production efficiency reduction and the like. Therefore, dispersibility and thermal stability are key indicators for evaluating the performance of insoluble sulfur. In order to improve the dispersibility of the product, the patent CN103303873A is added with sodium tripolyphosphate, zinc stearate, white carbon black, a scorch retarder, lignosulfonate and the like during sulfur melting, and the temperature is raised after stirring. The dispersing agent is added when the temperature of the molten sulfur rises, so that the dispersing agent is easy to be washed by a solvent in the later extraction, and the using effect of the dispersing agent is affected. Patent CN103303874A adds alum to improve the dispersibility of the product when the temperature of molten sulfur rises, but the alum can obviously increase the ash content of the product, so that the ash content of the product exceeds the standard (the ash content is lower than 0.3 percent according to national standard). Patent CN102732064A adds water-soluble polymer materials such as amylose, amylopectin, modified starch, cyclodextrin and the like into insoluble sulfur, and carries out powder coating after water dissolution to improve the dispersibility of the product, but the water-soluble polymer has polar groups such as hydroxyl and the like, and the insoluble sulfur is a nonpolar product, so that the water-soluble polymer is difficult to carry out good coating on the product, and the dispersing effect is influenced. Therefore, there is a need for a simple and efficient way to increase the dispersibility of insoluble sulphur products. Disclosure of Invention Aiming at the defects existing in the prior art, a method for improving the dispersibility and the thermal stability of insoluble sulfur is provided, so that the prepared insoluble sulfur has good dispersibility and thermal stability, and the process flow is simple and feasible, thereby being beneficial to improving the production efficiency. In order to solve the technical problems, the invention adopts the following technical scheme: A method for improving the dispersibility and thermal stability of insoluble sulfur, comprising the steps of: 1) Mixing naphthenic oil, a dispersing agent, a stabilizing agent and a compatibilizer to obtain a mixed material; the dispersing agent is one or more of dithiodibenzothiazyl, zinc stearate, dioctyl phthalate, polyethylene glycol monolaurate, oleyl alcohol and fatty alcohol polyoxyethylene ether; the compatibilizer is one or more of ethylene propylene diene monomer rubber, EVA resin and liquid butadiene rubber; the stabilizer comprises one or more of methyl styrene, pinene and hydrobromic acid; The addition amount of the naphthenic oil is 18-25% of the mass of the non-oil-filled inso