Polyesters
원료 | TPA (DMT); EG |
생산물 | polyesters |
적용 | Processes for the production of polyethylene terephthalate (PET) starting from ethylene glycol (EG) and terephthalic acid (TPA) or dimethylterephthalate (DMT). |
설명 | Description: In a multistage continuous process the raw materials EG and TPA (DMT) are comverted into a low-molecular precondensate by esterification (transesterification) and into high molecular, linear polymer by polycondensation reaction. Two routes are available for the esterification reaction:
1. Process being carried out under atmospheric pressure with corresponding ease of recycling and charging solid waste.
The reaction byproducts water (methanol) is separated from EG vapors in a reflux column. After adding catalyst, stabilizer and additives the prepolymer is forced through a superfine filter. Polycondensation reaction is performed under vacuum and elevated temperature. Special care went into the conception of the polymer finisher, which is equipped with a proprietary horizontal cage agitator without center-shaft, therefore minimizing the buildup of solidifying polymer layers. EG vapors contaminated with oligomers are drawn off through a special condensing system and sent to a recovery unit.
Batch process: Similar principles are applied to a two-stage batch process. The capacity of standard batch lines ranges up to 30 t/d. |