Durable Dyed Polyester Films UV Stability
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Solution Overview
Problem
Dyed polyester films experience significant degradation and color alteration when exposed to UV radiation, leading to fading and increased light transmission, which is a persistent issue in the tinted film industry despite the widespread use of the dip-dyeing process.
Innovation Solution
The development of optically clear dyed polyester films with a multilayer structure comprising a clear first and second outer layer of polyethylene terephthalate (PET) encapsulating a dyed core layer with thermally-durable dyes such as Pigment Yellow 147, Pigment Red 177, Pigment Black 31, and Pigment Red 122, which are dissolved in the molten PET, ensuring stability and resistance to UV radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dip-dyeing process is used to produce dyed polyester films, then the films can be efficiently manufactured with good initial color, but the films experience significant color degradation and fading after prolonged UV exposure
Solution Approach 1:
The patent changes the fundamental parameter of how dye is incorporated into the polyester film. Instead of using the conventional dip-dyeing process where dye is applied to the surface and absorbed, the patent uses extrusion to incorporate dye masterbatch into the molten polyester resin before film formation. This parameter change in the dyeing mechanism results in more uniform dye distribution and improved UV resistance while maintaining manufacturing efficiency
Solution Approach 2:
The patent employs composite materials by combining polyester resin with specific dye masterbatch formulations during extrusion. The use of concentrated dye masterbatch ( containing the dye dispersed in a carrier resin) creates a composite structure where the dye is uniformly distributed within the polyester matrix, improving color stability under UV exposure compared to surface-level dip dyeing
2Ease of manufacture
If conventional dyes are used in dip-dyeing, then the process is simple and widely adopted, but the dyes degrade significantly under UV radiation causing fading and color alteration
Solution Approach 1:
The patent changes the chemical parameter of the dye by specifying particular dye classes (azo dyes, anthraquinone dyes, phthalocyanine dyes, triarylmethane dyes, xanthene dyes) that have inherent UV resistance. These dyes are selected for their molecular stability under UV radiation, and they are incorporated via extrusion at controlled temperatures and concentrations to achieve both ease of manufacture and UV durability
Solution Approach 2:
The patent uses dye masterbatch as an intermediary carrier that facilitates the uniform distribution of UV-resistant dyes within the polyester resin during extrusion. The masterbatch acts as a pre-prepared concentrate containing the dye dispersed in a carrier resin, making the extrusion process simple while ensuring uniform dye distribution and UV stability in the final film
3Ease of manufacture
If dye is applied through dip-dyeing, then the process is well-established and easy to implement, but the dye distribution is uneven and color fastness deteriorates over time
Solution Approach 1:
The patent changes the physical parameter of dye incorporation from surface-level absorption (dip-dyeing) to bulk mixing during molten resin extrusion. The dye masterbatch is thoroughly mixed with the polyester resin in the extruder, ensuring uniform distribution at the molecular level before film formation. This results in consistent color throughout the film thickness and superior color fastness
Solution Approach 2:
The patent performs preliminary action by pre-preparing the dye masterbatch with the dye already uniformly dispersed in a carrier resin before the extrusion process. This pre-dispersion ensures that when the masterbatch is fed into the extruder with the polyester resin, the dye distributes uniformly throughout the molten polymer, eliminating the uneven distribution problems of dip-dyeing while maintaining process simplicity
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 films exhibit improved durability and color retention with a ΔEab* change of less than 5 after extensive UV exposure, maintaining optical clarity and low haze, significantly reducing color fading compared to conventional films.
Implementation Method 1
one or more dyes chosen from Pigment Yellow 147, Pigment Red 177, Pigment Black 31, Pigment Red 149, and Pigment Red 122, which are dissolved in the molten PET
Implementation Method 2
a clear first outer layer comprising polyethylene terephthalate (PET), a dyed core layer comprising PET and one or more dyes... and a clear second outer layer comprising PET
Data Source
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AI summary
The present disclosure relates to dyed polyester films whose color remains stable after prolonged exposure to UV radiation and to methods of making such dyed polyester films.