One of the problems that limits the amount of recycled PET (rPET) used in rigid packaging applications is the degree of yellowness that it can cause. The more rPET that is added to virgin PET during bottle manufacture, the more yellow the resulting bottle tends to become.
The source of the rPET used has a great influence on yellowing. Deposit-grade materials are in the greatest demand as they result in less yellowing than do curbside-grade material. Even virgin PET will discolor and yellow with each additional melting cycle.
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