METHOD FOR IMPROVING L COLOR IN PET POLYMERS

A method for improving the L * color of a polyethylene terephthalate polymer, the method comprising polycondensing dihydroxy ethylene terephthalate in a polyethylene terephthalate manufacturing process to produce the polyethylene terephthalate polymer, and wherein the process requires an antimony-containing catalyst, the method comprises the steps of: i) adding the antimony-containing catalyst at a temperature within an upper limit temperature range from the melting point of the BHET to 220 DEG C; and ii) exposing the BHET in a molten state to diol removal prior to addition of the antimony-containing catalyst. 一种用于改善聚对苯二甲酸乙二醇酯聚合物的L*颜色的方法，该方法包括在聚对苯二甲酸乙二醇酯制造工艺中将双羟基对苯二甲酸乙二醇酯缩聚以生产所述聚对苯二甲酸乙二醇酯聚合物，并且其中所述工艺需要含锑催化剂，该方法包括以下步骤：i)在所述BHET的熔点至220℃的上限温度范围内的温度处添加所述含锑催化剂；以及ii)在添加所述含锑催化剂之前，将处于熔融状态的所述BHET暴露于二醇去除。