Thermo-shrinkable Polyester Film Rupture Prevention
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Solution Overview
Problem
Thermo-shrinkable polyester films often rupture during processes involving tension, such as unwinding, slitting, and printing, leading to increased defect rates and reduced productivity due to non-uniform printing and mechanical instability.
Innovation Solution
A thermo-shrinkable polyester film with specific mechanical properties, including a strength of 3.5-6.5 kg/mm² in the direction perpendicular to the transverse direction, elongation at rupture of 50-700%, thickness uniformity of 4 or less, and a shrinkage ratio of 5% or less, manufactured through extrusion and controlled stretching to enhance stability and printing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the film is subjected to tension during unwinding, slitting, and printing processes, then the film can be processed and shaped, but the film may rupture leading to increased defect rates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the mechanical properties of the polyester film through controlled stretching ratios and heat treatment conditions. The film is stretched to specific ratios (machine direction: 1.05-1.2 times, transverse direction: 1.1-1.3 times) and heat treated at controlled temperatures (60-90°C for 1-10 seconds) to achieve optimal strength and elongation characteristics that prevent rupture during processing while maintaining processability
Solution Approach 2:
The patent implements preliminary action by pre-stretching and pre-heating the film before it undergoes tension-intensive processes like unwinding, slitting, and printing. This preliminary mechanical and thermal treatment prepares the film structure in advance, creating a more resistant state that prevents rupture during subsequent processing operations
2Adaptability or versatility
If the film is stretched to achieve thermo-shrinkable properties, then the film can be used for packing and labeling, but non-uniform printing may occur
Solution Approach 1:
The patent resolves this contradiction through parameter changes by precisely controlling stretching ratios and heat treatment parameters. The machine direction stretch ratio is controlled at 1.05-1.2 times and transverse direction at 1.1-1.3 times, with heat treatment at 60-90°C for 1-10 seconds. These controlled parameters ensure uniform molecular orientation and crystal structure formation, which guarantees both shrinkage performance and printing uniformity
Solution Approach 2:
The patent applies local quality by ensuring uniform stretching and heat treatment across the entire film surface. The controlled stretching ratios and heat treatment conditions create consistent molecular orientation and crystal structure throughout the film, resulting in uniform physical and optical properties that ensure both shrinkage performance and printing uniformity
3Reliability
If the film strength is increased to prevent rupture, then film integrity improves, but the film may become less flexible and difficult to process
Solution Approach 1:
The patent resolves this contradiction through parameter changes by optimizing the balance between strength and flexibility through controlled stretching and heat treatment. The film is stretched to specific ratios (machine direction: 1.05-1.2 times, transverse direction: 1.1-1.3 times) and heat treated at controlled temperatures (60-90°C for 1-10 seconds) to achieve optimal mechanical properties that provide both strength and flexibility
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 film prevents rupture during manufacturing and use, ensuring product reliability, process stability, and increased productivity by maintaining mechanical integrity and uniformity, thus reducing defect rates and improving the external appearance of final products.
Implementation Method 1
a container is clothed in the label or bag, passed, for example on a belt conveyer, through a shrinking tunnel (steam tunnel) wherein heated steam is blown causing thermal shrinkage
Implementation Method 2
the film in the roll is unwound, slit into a desired width, and then rewound into another roll. Subsequently, various characters and figures, including a product name and the like, are printed on the resulting film
Implementation Method 3
the film is then heat-treated, thus preparing a thermo-shrinkable film
Data Source
AI summary
Disclosed is a thermo-shrinkable polyester film having superior thermal shrinkage properties. The thermo- shrinkable polyester film has a strength of 3.5~6.5 kg/mm2 in a direction perpendicular to a main shrinking direction at an initial elongation less than 10%, an elongation at rupture of 50~700% in a direction perpendicular to a main shrinking direction, a thickness uniformity (ΔR) of 4 or less and a shrinkage ratio of 5% or less in a direction perpendicular to a main shrinking direction, thus preventing the rupture thereof in a rolling process and so on and ensuring process stability and productivity.