The major operations involved in the manufacture of polyester resin are esterification and blending – which are carried in their respective kettles. The most common raw materials used are polypropylene glycol, melic anhydride and styrene monomer. In addition small quantities of inhibitors and other additives are required for the process.
The process of Polyester Resin manufacaturing involved is poly condensation reaction and blending the polyester resin with the monomer. Due to the sensitivity of polyester resin to contamination; in the course of condensation reaction and during subsequent handling the material of construction must be carefully selected.
The esterfication reactor vessel is changed through a manhole with required amount of glycol and the solid anhydride. The mass is heated up to 200°C under agitation and inert gas N2 is slowly applied. The partial condenser condenses the glycol but process the water to the total condenser. The esterification is continued until a predetermined acid value 10 to 15 is reached. After achieving the predetermined viscosity the heating is stopped and the batch is dropped in to the blending kettle. In the blending kettle the batch is cooled to 100 – 102°. Styrene is pumped in the blender and viscosity is adjusted until the batch attains room temperature. The batch is then pumped through filter in to the storage tanks.
7.5 ton to 10 ton depending on % solid base.