A kind of isoprene rubber and its continuous production method

Abstract

The invention provides a continuous production method of isoprene rubber and the isoprene rubber produced thereby. The method is carried out in a plurality of adiabatic reactors which are connected in series. The method comprises the following steps of: continuously feeding a reactant containing isoprene, a rare earth catalyst and a solvent from a first adiabatic reactor of the plurality of series-connected adiabatic reactors; refilling the solvent to at least one of the adiabatic reactor following the first adiabatic reactor in order to polymerize isoprene to obtain a rubber solution; and treating the rubber solution by coagulating, dewatering and drying in sequence, wherein an isoprene monomer in the material fed in the first adiabatic reactor is at the concentration of 14 to 50 wt%; and the rare earth catalyst contains neodymium carboxylate with 7 to 14 carbon atoms, aluminum alkyl, halide and conjugated diene. According to the method, the output can be increased, the monomer conversion rate of isoprene reaches more than 96%, and the prepared isoprene rubber contains at least 98wt% of cis-1,4-structure based on the content.

Description

technical field [0001] The invention relates to a continuous production method of isoprene rubber and the isoprene rubber produced by the method. Background technique [0002] The domestic production capacity of natural rubber is limited, the import volume of natural rubber is increasing year by year, and the price is also rising all the way. Isoprene rubber with excellent performance has been proved to be able to partially replace natural rubber in practical applications. Therefore, the development and production of isoprene rubber has become the main way to solve the shortage of natural rubber in my country. The isoprene rubber with high cis-1,4-structure content (the structure content is greater than 96% by weight) obtained by polymerization with a neodymium rare earth catalyst has excellent properties, which are close to natural rubber (NR), and are also superior in some properties. in natural rubber. [0003] CN101045768A discloses a homogeneous catalyst composed of n...

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Problems solved by technology

[0006] CN101880344A discloses an adiabatic method for solution polymerization of rare earth isoprene rubber, which uses a three-component catalyst system containing rare earth elements, alkyl aluminum and halides, isoprene (monomer concentration below 15%), Catalyst system and solvent enter multiple polymerization tanks in series at 0-35°C for continuous adiabatic polymerization, and the conversion rate of isoprene monomer is relatively low, generally below 90%.

In addition, in this method, the temperature of the last tank is too high when carrying out continuous polymerization in 7 tanks, which may increase the gel content, thereby affecting the performance of isoprene rubber.

In addition, when the rare earth compound uses acidic neodymium phosphonate, since the rare earth phosphonate is insoluble in hydrocarbon solvents, the rare earth phosphonate is suspended in aliphatic or alicyclic hydrocarbons when preparing this type of catalyst, and the prepared catalyst is non-toxic. Homogeneous state, poor catalyst stability, this situation is not comparable to the situation using neodymium carboxylate

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