Thermo-shrinkable Polyester Film Haze and Lubricity Control
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Solution Overview
Problem
Thermo-shrinkable polyester films face challenges in achieving transparency and reducing defective fractions due to lubricity issues during the film forming and post-treatment processes, which affect the visibility of contents in containers and the quality of the final product.
Innovation Solution
A thermo-shrinkable polyester film with particles dispersed in a polyester resin matrix, featuring a haze of 1.0% or less, a contraction ratio of 35-80% in the main contraction direction, and an inline coating layer with particles of 80-200 nm, utilizing copolyesters and homopolyesters for improved transparency and lubricity, while incorporating additives like antistatic agents to enhance processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If particles are added to improve lubricity during film forming and post-treatment processes, then ease of manufacture is improved, but transparency deteriorates due to increased haze
Solution Approach 1:
The patent applies parameter changes by precisely controlling particle size (0.1-5 μm) and concentration (0.01-1 wt%) to optimize the balance between lubricity and transparency. By adjusting these parameters, the invention achieves adequate lubrication during processing while maintaining high transparency with haze of 10% or less, thereby resolving the contradiction between ease of manufacture and transparency.
2Illumination intensity
If the film is made highly transparent to improve visibility of contents, then appearance quality is improved, but lubricity deteriorates leading to increased defective fraction
Solution Approach 1:
The patent resolves this contradiction by changing parameters of particle characteristics - using ultra-fine particles with size of 0.1-5 μm and controlling concentration at 0.01-1 wt%. These parameter changes enable the film to maintain high transparency (haze ≤10%) while still providing sufficient lubricity during film forming and post-treatment processes, preventing processing defects.
Solution Approach 2:
The invention creates a composite material system by dispersing inorganic particles (such as calcium carbonate, barium sulfate, or silica) within the polyester resin matrix. This composite structure provides both the transparency required for content visibility and the lubricity needed for smooth processing, simultaneously addressing both requirements.
3Ease of operation
If particle size is increased to improve lubricity, then ease of operation is improved, but transparency deteriorates and defective fraction increases
Solution Approach 1:
The patent applies parameter changes by defining a specific particle size range of 0.1-5 μm, with preference for 0.5-2 μm. This precise parameter control ensures particles are fine enough to maintain high transparency and avoid visible defects, while still providing adequate lubricity for ease of operation during film handling and processing.
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 solution provides excellent visibility of contents, reduces defective fractions, and prevents blocking between films, ensuring high-quality, transparent, and uniformly contracted labels with improved mechanical properties and productivity.
Implementation Method 1
particles dispersed in a polyester resin matrix... reduces the defective fraction attributable to lubricity in a film forming process or a post-treatment process... prevents blocking between films
Implementation Method 2
the thermo-shrinkable polyester film... a contraction ratio of the thermo-shrinkable polyester film in a main contraction direction is 35 ∼ 80% when it is treated with hot water at 90 °C for 10 seconds
Data Source
AI summary
The present invention provides a thermo-shrinkable polyester film, which has good visibility to contents included in a container and can allow the contents to appear fresh when it is used as a label for covering a container due to its low haze, and which can prevent protrusions or wrinkles from being formed thereon when it is rolled during a film forming process or a post-treatment process.