摘要 |
<p>The present invention relates to a polyethylene terephthalate (PET) resin and a process for producing PET resin having conventional catalysts such as antimony compounds and a glycol insoluble tungsten compound, in particular tungsten trioxide or tungsten carbide, as co-catalyst. The tungsten compound as a co-catalyst increases the rates of solid state polymerization and improves the 'L' color value.</p> |