Thermoplastic polyesters PET and PBT for injection moulding

In the field of plastics, the term "polyester" covers the following two families of very different products.

• Unsaturated polyesters are generally liquids whose curing is due to polymerization triggered by the addition of a catalyst (see [1] ).

  These unsaturated polyesters are thermosetting materials.

• Saturated polyesters, the subject of this booklet, are finished products, processed by fusion (injection, extrusion...).

  These saturated polyesters are thermoplastics.

Apart from textile fibres, thermoplastic polyesters are used in the following applications:

• engineering plastics, glass fiber-reinforced and non-glass fiber-reinforced thermoplastic polyesters, for molding electrical engineering, household appliance and mechanical parts;

• films (packaging, audiovisual) ;

• soft drink bottles in particular;

• POWDER PAINTS ;

• hot-melt adhesives.

This article will deal only with the first of these applications: the use of thermoplastic polyesters as engineering plastics.