Preparation method of sulfur-modified chloroprene rubber with high latex Mooney viscosity stability

A Mooney viscosity, neoprene technology, applied in the field of sulfur-adjusted neoprene preparation, can solve the problems of unstable chain scission products, decreased vulcanizate performance, poor storage stability, etc. The effect of good quality and increased production

Active Publication Date: 2015-03-11
SHANNA SYNTHETIC RUBBER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The present invention solves the instability of the final chain-broken product of the existing sulfur-modified chloroprene rubber, the Mooney viscosity of the latex will change greatly after being placed for a period of time, the storage stability of the raw rubber is poor, and it will become hard and plastic after long-term storage. reduce, processability deteriorates and the performance of vulcanizate declines, etc., a method for preparing sulfur-adjusted chloroprene rubber with high latex Mooney viscosity stability is provided

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Embodiment 1: a kind of preparation method of the sulfur-modified chloroprene rubber with high latex Mooney viscosity stability comprises the steps: under nitrogen protection, add 1000g chloroprene monomer, 36g common rosin, 3.6 g sulfur, 2.7g dithiotetrabutylthiuram, 2.7g 2-mercaptobenzothiazole. While stirring rapidly, add an aqueous phase containing 1100 g of soft water, 7.5 g of sodium hydroxide, 7.2 g of β-naphthalenesulfonic acid formaldehyde condensation sodium salt, and 0.9 g of sodium dithiodibutylcarbamate. After the emulsification is completed at a temperature of 40°C, adjust the system temperature to a reaction temperature of 38°C, use 4g of potassium persulfate solution with a mass concentration of 4% as an initiator to initiate polymerization, and add the pre-prepared solution when the specific gravity reaches 1.075-1.077 The terminator stops the polymerization reaction. Use nitrogen to remove unreacted monomers, then divide the latex into 3 parts, and ad...

Embodiment 2

[0017] Embodiment 2: a kind of preparation method of the sulfur-modified chloroprene rubber with high latex Mooney viscosity stability comprises the steps: under nitrogen protection, add 1000g chloroprene monomer, 36g common rosin, 3.6 g sulfur, 2.7g tetrabutyldithiothiuram, 2.25g 2-mercaptobenzothiazole. While stirring rapidly, add an aqueous phase containing 1100 g of soft water, 7.5 g of sodium hydroxide, 7.2 g of β-naphthalenesulfonic acid formaldehyde condensation sodium salt, and 1.35 g of sodium dithiodibutylcarbamate. After the emulsification is completed at a temperature of 40°C, adjust the system temperature to a reaction temperature of 40°C, use 3g of potassium persulfate solution with a mass concentration of 3% as an initiator to initiate polymerization, and add the pre-prepared The terminator stops the polymerization reaction. Use nitrogen to remove unreacted monomers, then divide the latex into 3 parts, and adjust the pH of each latex to 5-7 after standing for 0...

Embodiment 3

[0019]Embodiment 3: a kind of preparation method of the sulfur-modified chloroprene rubber with high latex Mooney viscosity stability comprises the following steps: under nitrogen protection, add 1000g chloroprene monomer, 36g common rosin, 3.6 g sulfur, 2.7g tetrabutyldithiothiuram, 1.8g 2-mercaptobenzothiazole. While stirring rapidly, add an aqueous phase containing 1100 g of soft water, 7.5 g of sodium hydroxide, 7.2 g of β-naphthalenesulfonic acid formaldehyde condensation sodium salt, and 1.8 g of sodium dithiodibutylcarbamate. After the emulsification is completed at a temperature of 40°C, adjust the system temperature to a reaction temperature of 42°C, use 1g of potassium persulfate solution with a mass concentration of 5% as an initiator to initiate polymerization, and add the pre-prepared The terminator stops the polymerization reaction. Use nitrogen to remove unreacted monomers, then divide the latex into 3 parts, and adjust the pH of each latex to 5-7 after standin...

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PUM

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Abstract

The invention belongs to the technical field of chloroprene rubber preparation, and provides a preparation method of a sulfur-modified chloroprene rubber with a high latex Mooney viscosity stability in order to solve the problems that the final chain-broken products of conventional sulfur-modified chloroprene rubber are not stable, the Mooney viscosity of latex changes after being stored for a while, the storage stability of raw rubber is bad, the rubber will become hard and the rubber plasticity is reduced after long-term storage, the processing performance turns worse, and the performance of sulfurized rubber degrades. The preparation method comprises the following steps: dissolving sulfur, tetrabutyl thiuram disulfide, and 2-mercaptobenzothiazole into chloroprene monomers to prepare an oil phase; mixing the oil phase with a prepared water phase to carry out emulsification, adding an initiator to carry out reactions; stopping the reactions when the specific weight of the system reaches 1.075 to 1.077, allowing the system to stand still for a while, then adjusting the pH value, cooling on the drum to carry out gelation, and cleaning and drying the gel so as to obtain the target product. The polymerization can be easily controlled, the formula and the technology are simple and convenient, the chain breaking technology is omitted, the molecular weight can be adjusted to a proper value in a short time, the Mooney viscosity of the obtain latex is stable; and the problems that the latex viscosity is hard to control and the storage stability of the latex is bad are solved.

Description

technical field [0001] The invention belongs to the technical field of chloroprene rubber preparation, in particular to a method for preparing sulfur-adjusted chloroprene rubber with high latex Mooney viscosity stability. Background technique [0002] Sulfur-adjusted chloroprene rubber is obtained by copolymerization of sulfur and chloroprene. The macromolecular chain contains straight-chain, branched or cross-linked oversulfur bonds. Usually, dithiotetraethylqiuran is added under alkaline conditions. Mu (TETD), etc. can break the S-S bond to obtain a polymer with a suitable Mooney viscosity. However, there are many defects in this chain scission system, for example, the quality of the monomer, the pH value of the chain scission system, the amount of sulfur, TETD, the polymerization conversion rate and the scission temperature all have a great influence on the chain scission rate. For example, the higher the temperature, the faster the chain breaking speed; the higher the p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F136/18C08F2/38C08C1/14
Inventor 毛利军张淑娟李俊张志刚高文龙洪治安魏凯齐中华
Owner SHANNA SYNTHETIC RUBBER
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