After the centralized production of domestic shunding plant in recent years, the oversupply has become increasingly obvious. Some petrochemical plants have been in a state of shutdown since the beginning of the year, and the overall operating rate fluctuates between 40% and 50%.In addition, the downstream tire enterprises affected by internal and external problems, the market also entered the reshuffle period, the demand for butyl rubber has decreased without increasing, also intensified competition between production enterprises, or promote the improvement and upgrading of production technology.
1. Butadiene rubber
Butadiene rubber is commonly known as cis-rich butadiene rubber, butadiene rubber as raw material, by nickel naphthenate as catalyst, synthesis, generated by solution polymerization is industrialized earlier, mature technology of general synthetic rubber varieties, and has excellent abrasion resistance, good flexing resistance, high resilience, small hysteresis loss, low heat, good low temperature performance characteristics;Widely used in the manufacture of tire tread, side tire body, also used in the manufacture of rubber tape, rubber hose and other industrial products, but its characteristics are low tear strength, wet slip resistance is not good, cold flow phenomenon of raw rubber.
Structure of rare earth butadiene rubber content is higher, narrow molecular weight distribution, do not contain branched and gel, therefore has the environmental security, convenient processing, using the production of rubber mixing rubber () have a higher fatigue resistance and crack growth and cutting resistance, wear resistance, is used in the manufacture of green tire sidewall and the ideal raw material, made of the tire rolling resistance lower, at the same time can reduce tire wear.
Rare earth butadiene rubber catalytic system
According to the catalytic system, the technologies used by the world's shunding rubber production companies can be divided into five major systems: nickel, cobalt, lithium, titanium, and rare earth (neodymium).Titanium, nickel and cobalt system is the mainstream in elimination trend, rare earth system in the development stage, lithium is butadiene rubber is mainly used for production, impact polystyrene modification for the nickel butadiene is our country in the 1960 s the successful development of highly active nickel catalysts, respectively in 1965 in jinzhou, lanzhou, began to industrialized production, butadiene rubber production of new technological achievements in 1985, special-class award of national scientific and technological progress, after half a century of several generations efforts, China's nickel production technology and nickel butadiene product quality in the world advanced level.
Characteristics of nickel catalytic system:
1. Nickel catalytic system is a multicomponent system. The dosage ratio, feeding mode and aging mode of catalysts not only affect the activity of the catalytic system, but also affect the molecular weight of the polymer.
2, nickel catalyst system stability, polymerization temperature, to adapt to a wide range, the reaction temperature above 120 ℃, the system still not inactivation, has good temperature resistance.
3. The nickel catalytic system has good directivity and is less affected by the amount of catalyst and the concentration of monomer.
4. The nickel catalyzed system caused a large number of chain transfer of butadiene during the polymerization process, leading to chain termination.
Polymerization characteristics of rare earth catalytic system:
1. Saturated hydrocarbon hexane is used as solvent, which is conducive to environmental protection;
2. High monomer conversion rate, even reaching 100%;
3. It is not easy to produce cross-linking reaction and generate gel.
Properties of rare earth butadiene rubber
The butadiene rubber produced by the rare earth catalysis system has a higher molecular chain regularity and the highest Mooney viscosity, indicating that the molecular chain has a certain amount of long chain branching, indicating a higher degree of linearity. In addition, the molecular weight distribution of the nickel series is narrower than that of the rare earth series.
By comparison, the rare earth catalyzed polymerization of butadiene rubber has a high cis structure, less branched, no gel, so it has a good linear structure, known as high dimensional regularity of butadiene rubber.It can produce strong crystallization under the action of stretching, that is, with "stress crystallization ability, which gives rare earth butadiene rubber high self-viscosity, good tensile properties and advantages of abrasion resistance and fatigue resistance, as the first rubber for the manufacture of high-performance tires.
Development trend of rare earth butadiene rubber
Japan synthetic rubber company research found that rare earth rubber is the future development trend.Rare earth glue in line with the high performance tire in high speed, safety, energy saving, environmental protection, etc, is now the fastest-growing BR varieties, with the European and American countries tire aspects and so on energy conservation and environmental protection, safety technical regulations require stricter, products for export-oriented enterprises and technical barriers, domestic resource crisis and environmental pollution control is imminent, industry policy encourages the development of green tire comprehensively, and will gradually set up industry barriers to entry and backward product capacity elimination mechanism, green tire tire industry has become the development trend, with the continuous improvement of production technology and the improvement of product requirements, other domestic seibel butadiene rubber overcapacity,Rare earth butadiene rubber or the only choice of the production enterprises.