关键词: 聚对苯二甲酸乙二醇酯（PET）, 共聚改性, 冰箱透明件注塑, 加工性, 耐热性, 结晶性

Abstract: Polyethylene terephthalate (PET) has become the primary alternative to general purpose polystyrene (GPPS) in the refrigerator industry due to its excellent impact and corrosion resistance. However, its poor processability, low heat resistance, and tendency to crystallize have hindered its wide application. To address these issues, innovative molecular-level modification of PET is carried out in accordance with actual refrigerator manufacturing and service conditions to improve its flowability, crystallinity, heat resistance, and transparency. Compared with unmodified PET, the modified material enables stable injection molding of complex and large components, with a wider and lower processing temperature window (down to 240 ℃). It can withstand 65 ℃, 93% humidity, and thermal cycling between -40 ℃ and 65 ℃. Moreover, its higher transparency and gloss effectively improve the refrigerator door-opening experience.

Key words: Polyethylene terephthalate (PET), Copolymer modification, Refrigerator transparent parts injection molding, Processability, Heat resistance, Crystallinity