Monobutyltin trichloride is one of the organotin compounds and is also abbreviated as MBTC or MBTCl. At room temperature it is a clear to yellowish liquid, not very volatile and soluble in water and organic solvents.
The most important area of application is in the coating of glass, but monobutyltin trichloride is also used as a catalyst and stabilizer. The substance is also an intermediate from which numerous other organotin compounds are produced, such as di- and tributyltin catalysts for esterification and transesterification reactions.
To increase the scratch resistance of glass, it is given a tin oxide coating that closes microcracks and increases resistance to physical influences. Monobutyltin trichloride is an important raw material for this coating.
In the production of flat glass, for example for panes, it is used with other ingredients in a homogeneous formulation that creates an even and wafer-thin layer on the glass.
For the coating of container glass (bottles, glasses, etc.) monobutyltin trichloride is applied directly. The melted glass mass is cut into precisely portioned glass lumps (gobs), which are guided into the molds by gravity slides, where they are pressed into the shape of the final bottle in a two-stage process. These still hot bottles then pass through a coating hood in which a monobutyltin trichloride vapor is sprayed. MBTC adsorbs on the hot glass surface and is oxidized there. A layer of tin oxide is created, which forms the coating. After passing through a hardening furnace, a sprayed-on polyurethane layer forms the final surface coating.
Monobutyltin trichloride is most commonly used for this task because it is easily oxidized on or near the hot glass surface. The resulting tin oxide coating is transparent to visible light, but reflects infrared radiation and thus helps to keep the bottled drinks cool. With the finished coating process, the bottles are protected against abrasion and breakage and are therefore much better suited to the demands of industrial production and everyday life.
Use as a Catalyst
In addition to being used for glass coatings, monobutyltin trichloride can also be used as an esterification catalyst for the production of polyurethane foams and silicones.
Butyltin Trichloride Stabilizers for PVC
MBTC can also be used as a stabilizer in various PVC plastics. If these are introduced together with dialkyltin compounds, a synergetic effect on the effectiveness of the stabilizer can be observed, which is why they are usually used together.
Transport and Storage
Monobutyltin trichloride from BNT production is supplied in steel cans with a polyethylene liner. When stored in sealed original containers, there is a minimum shelf life of 6 months without any impairment in quality. A brownish color may occur during extended storage, but this has no influence on the application or effectiveness of the product.