RPET BOPET Film Process via Depolymerization and Purification
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Solution Overview
Problem
Current methods for producing biaxially oriented polyester (BOPET) films from recycled polyethylene terephthalate (RPET) are limited by productivity and quality issues, leading to restricted use in high-grade applications and significant reliance on virgin PET, which is environmentally unfriendly and costly.
Innovation Solution
A process that produces RPET granules from post-consumer PET waste through depolymerization, followed by filtration and decolourisation to remove contaminants, which are then used to manufacture BOPET films with up to 90% recycled content, meeting food packaging compliance standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If post-consumer recycled PET is used to manufacture BOPET films, then environmental impact is reduced and production costs are lowered, but quality and productivity issues arise that restrict use in high-grade applications
Solution Approach 1:
The patent applies preliminary action through extensive pre-treatment of recycled PET materials before film manufacturing. This includes sorting, washing, drying, and quality assessment stages that prepare the recycled materials in advance to ensure they meet the required specifications for high-grade BOPET film production, thereby resolving the quality issue while maintaining high recycled content
Solution Approach 2:
The patent utilizes parameter changes by controlling and optimizing various process parameters during the manufacturing sequence. This includes adjusting temperature, pressure, and processing conditions at different stages (depolymerization, purification, extrusion, orientation) to transform the recycled PET into high-quality BOPET film that meets food packaging standards while maintaining high recycled content
2Loss of substance
If post-consumer recycled PET is used to manufacture BOPET films, then environmental impact is reduced, but production costs increase due to additional processing requirements
Solution Approach 1:
The patent applies continuity of useful action through an integrated, continuous processing system that combines multiple operations (depolymerization, purification, extrusion, orientation) in a seamless flow. This eliminates idle time and intermediate handling losses, making the complex recycled PET processing economically viable by ensuring every step contributes directly to product quality without unnecessary cost additions
3Object-affected harmful factors
If virgin PET is used to ensure food compliance and prevent chemical migration, then food safety is maintained, but environmental friendliness and cost-effectiveness are compromised
Solution Approach 1:
The patent applies the extraction principle by removing and eliminating harmful contaminants from the recycled PET material through sophisticated purification processes. This includes filtration, washing, and quality control stages that extract and remove any chemicals or particles that could migrate to food, thereby enabling the use of recycled PET (up to 90% content) while maintaining food safety compliance without requiring virgin PET
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process enables the production of BOPET films with properties comparable to virgin PET films, while significantly increasing the use of recycled PET, reducing environmental impact, and lowering production costs.
Implementation Method 1
RPET granules produced by depolymerisation of polyethylene terephthalate (PET) bottle flakes
Implementation Method 2
filtration and decolourisation to remove contaminants
Implementation Method 3
decolourisation to remove contaminants
Implementation Method 4
extruding the molten polyester through a die
Implementation Method 5
biaxially oriented polyester film
Data Source
Figure 1
AI summary
The present disclosure relates to a process for producing bi-axially oriented polyester (BOPET) film from the Polyethylene Terephthalate (RPET) granules. The present process is capable to produce single or multilayer bi-axially oriented polyester film having uniform thickness. The RPET film product having similar quality like virgin PET Films. The BOPET film of present disclosure meets the requirement of various food packaging compliance/standards. The said bi-axially oriented polyester film has good elongation, mechanical and /or thermal properties and useful in high end food and pharma packaging and industrial applications.The present disclosure also relates to an apparatus for producing the bi-axially oriented polyester film from the PCR Polyethylene Terephthalate (RPET) granules. Producing the RPET film from the PET post-consumer waste has the various environment and cost benefits compare to virgin/fresh PET film.