The primary function of hot washing is to vigorously remove various
stubborn contaminants from PET bottle flakes (fragments) through
high temperatures and chemical agents, thereby obtaining
high-purity recycled PET fragments and laying the foundation for
subsequent high-value applications.
Detailed Breakdown of Roles and Functions
Removal of Organic Residues and Oils
Function: Residual contents originally in the bottles, such as soft
drinks, fruit juices, oils, sauces, etc., leave behind organic
residues like sugars, fats, and proteins. Hot water (typically
combined with cleaning agents) can more effectively dissolve and
emulsify these stubborn stains, which cold water washing cannot
achieve.
Removal of Labels and Adhesives
Function: Labels on the bottles (usually made of PVC, PE, or paper)
are firmly attached with adhesives (glue). The hot washing process
softens and shrinks the label materials, breaks down the
adhesiveness of the glue, and causes them to detach from the PET
flakes. Simultaneously, it effectively dissolves and removes
residual adhesives, preventing them from melting and contaminating
the PET melt during subsequent processing.
Sterilization and Disinfection
Function: High temperatures (typically in the range of 70°C to 85°C
during hot washing) effectively kill bacteria, molds, and other
microorganisms that may be present during the recycling process,
meeting the requirements for food-grade or high-standard hygienic
materials.
Improvement of Subsequent Process Efficiency and Product Quality
Function: Thoroughly hot-washed PET flakes exhibit extremely high
purity, which directly brings the following benefits:
Reduction of Impurity Carbonization: During subsequent melting and
extrusion processes, organic impurities can carbonize and turn
black at high temperatures, leading to black spots in the product,
which affects appearance and performance. Hot washing prevents this
at the source.
Ensuring Melt Quality: A pure PET melt has more stable viscosity
(intrinsic viscosity, IV value) and better physical properties,
facilitating fiber spinning, pelletizing, and the production of
high-quality recycled PET pellets.
Meeting High-End Applications: Only thoroughly hot-washed and
deeply purified rPET can be used to produce food-contact materials
(such as new beverage bottles) and high-grade textile filaments,
which require extremely high purity standards.
Our company has been in the plastic recycling field for more than
20 years with much experience on the plastic recycling and
pelletizing. For more information, please contact us freely.
