As an important raw material for heavy anti-corrosion coatings, chlorinated rubber has been widely concerned by the industry. China began to produce small-scale chlorinated rubber from the early 1970s, mainly the carbon tetrachloride solvent process. According to the revised Montreal Protocol, the production and use of carbon tetrachloride is banned in 2009. Therefore, in 2009, the carbon tetrachloride solvent chlorinated rubber production process will be eliminated, although high chlorinated polyethylene, high chlorinated polypropylene, thermoplastic acrylic resin, etc. can replace chlorinated rubber in some properties, but these alternatives The anti-corrosion performance and anti-aging performance are far lower than that of chlorinated rubber, especially the corrosion resistance of marine conditions. Chlorinated rubber coating is still the preferred anti-corrosion material.
At home and abroad, a lot of research work has been done on the production of chlorinated rubber with new solvent instead of carbon tetrachloride. The substitute solvent is mostly dichloroethane solvent. It has been successful in the laboratory to synthesize chlorinated rubber with dichloroethane as solvent. . However, since dichloroethane has a low boiling point, a high vapor pressure, and a wide explosion range in the air, an explosive gas is formed at every stage in the production process, and thus industrialization has not yet been achieved. The use of new solvents instead of carbon tetrachloride to produce chlorinated rubber technology is still a hot spot in the industry and an inevitable trend in the development of the industry.
In the production process of chlorinated rubber, natural rubber needs to be dissolved in a solvent to form a homogeneous solution. Therefore, the solvent must meet the following basic requirements:
1 can dissolve natural rubber, which is the basis for forming a homogeneous solution.
2 can dissolve chlorinated rubber. If the chlorinated rubber formed by chlorination and the intermediate product in the chlorination process are not well compatible with the solvent, gelation will occur during the chlorine reaction, and the chlorination reaction cannot be completed.
3 has a certain amount of absorption of chlorine.
4 boiling point of 60--100 degrees, the boiling point is too low, the temperature of the chlorination reaction is difficult to control within a reasonable range, the boiling point is too high, the desolvation is difficult.
5 Solvent does not participate in the reaction of the chlorination process.
Pilot main equipment:
Dissolving kettle: 2000L
Chlorination kettle: 2000L
Desolvation tower: Φ600×6500
Product application performance test
The chlorinated rubber products industrially produced by the above four different solvents are commissioned by domestic authorities for practical application testing. The main technical indicators are tested in accordance with the People's Republic of China industry standard (HG/T2798-1996) chlorinated rubber anticorrosive coatings. Relevant requirements for rubber anti-corrosion topcoats.
The test data shows that the quality index of the new solvent chlorinated rubber has reached the quality index of the domestic chlorinated rubber and foreign chlorinated rubber. The new solvent as a new chlorinated solvent can fully meet the process and product performance requirements.
The advantages of the new solvent process
Highly dispersible reactor
Since the absorption rate of chlorine gas is the main controlling factor in the whole chlorination reaction, the general volumetric reactor can not meet the low chlorination rate. We have designed a highly efficient reaction equipment with high dispersion, which is characterized by gas. The liquid contact area is large, about 200 times of the reaction kettle, which effectively increases the apparent reaction speed, and the chlorination effect is obviously improved, which reduces the equipment investment of the device.
Efficient solvent recovery technology.
The high-boiling solvent is used to absorb the condensed tail gas, and then the new solvent and the high-boiling solvent phase can be separated by simple distillation, thereby greatly improving the recovery rate of the new solvent. This solvent-efficient recycling technology is our company. Independent research and development is also the only one in China.
The production process achieves closed loop and zero emissions. A green process for the production of chlorinated rubber.
The carbon tetrachloride solvent production process was eliminated, and the carbon tetrachloride solvent which has a destructive effect on the atmospheric ozone layer is not used in the production process. Solvent method
The new solvent method chlorinated rubber production process has the advantages of high efficiency, energy saving, environmental protection, etc., and a new era of vigorous development of solvent-based chlorinated rubber has arrived. Therefore, our company's high-quality chlorinated rubber products and high-chlorinated polyethylene resin products can meet the cravings of the domestic and foreign markets in the coatings industry and the adhesive industry.