Biaxially Oriented Polyester Film with SiO2 Particles for Greenhouse Light Scattering
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Solution Overview
Problem
Greenhouse blind films require high transparency, UV stability, reduced flammability, and optimal light scattering to balance light supply and heat management, while also preventing excessive yellowing or embrittlement over time, and must be economically producible in a specific thickness range.
Innovation Solution
A biaxially oriented polyester film with silicon dioxide particles and organic UV stabilizers, achieving transparency between 70-92%, scattering factor between 2-8, and haze between 60-95%, with a thickness of 13-25 μm, and incorporating phosphorus-based flame retardants for reduced flammability, ensuring mechanical strength and UV protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light scattering is increased to improve light distribution, then plant illumination is improved, but transparency decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution (d10, d50, d90 values), particle content (0.1-5% by weight), and refractive index mismatch between particles and matrix. These parameter optimizations enable the film to achieve scattering factor SF of 1.5-5.0 while maintaining transparency of 70-90%, resolving the contradiction between light scattering and transparency.
Solution Approach 2:
The patent uses composite materials by incorporating inorganic light-scattering particles (such as TiO2, SiO2, BaSO4) into the polyester film matrix. This composite structure enables the film to simultaneously achieve light scattering functionality and maintain high transparency, with the particles dispersed uniformly to avoid excessive light blocking while providing sufficient scattering for plant illumination.
2Reliability
If UV stabilizer is added to prevent yellowing and embrittlement, then UV stability is improved, but flammability increases
Solution Approach 1:
The patent introduces flame retardant additives as intermediary substances that mediate between UV stability and flammability requirements. The flame retardants (such as aluminum hydroxide, magnesium hydroxide, or phosphorus-based compounds) work synergistically with UV stabilizers to provide both UV protection and flame resistance, counteracting the increased flammability that would otherwise result from UV stabilizer addition.
Solution Approach 2:
The patent creates a multi-component composite material system comprising polyester matrix, UV stabilizers, and flame retardants. This composite formulation achieves a balance between UV stability and flammability by combining materials with complementary properties, ensuring the film meets both long-term durability requirements and fire safety standards for greenhouse applications.
3Strength
If film thickness is increased to improve mechanical strength, then strength is improved, but light scattering increases excessively
Solution Approach 1:
The patent applies parameter changes by optimizing the film thickness to a specific range (15-50 μm) and controlling the particle size distribution and concentration within defined limits. This parameter optimization ensures that the film achieves sufficient mechanical strength for greenhouse blind applications while maintaining appropriate light scattering characteristics, preventing excessive scattering that would occur with thicker films.
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 maintains transparency and mechanical strength, prevents yellowing and embrittlement, and achieves effective light scattering and reduced flammability, making it suitable for long-term greenhouse use while controlling heat and light distribution efficiently.
Implementation Method 1
the film comprises at least 1.0% by weight of SiO2 and at most 2.5% by weight of SiO2, wherein the d50 value of these SiO2 particles is from 3 to 9 μm, the SV value of the film is at least 700, the scattering factor SF of the film is at least 2 and not more than 8
Implementation Method 2
All of the external layers comprise at least 0.3% by weight (based on the weight of the layer) of an organic UV stabilizer
Data Source
AI summary
The invention relates to biaxially oriented, UV-stabilized polyester films incorporating silicon dioxide particles as light-scattering particles and a UV stabilizer; a process for producing the same and to use thereof in greenhouse blinds. The invention particularly relates to single- or multilayer polyester film with transparency from 70 to 92 %, where:the film includes at least 1.0% by weight to at most 2.5% by weight of SiO2, with the d50 value of these SiO2 particles ranging from 3 to 9 μm,the SV value of the film is at least 700,the scattering factor SF of the film is at least 2 and not more than 8,the haze of the film is from 60 to 95%, andthe clarity of the film is from 15 to 40%; andall of the external layers comprise at least 0.3 % by weight of an organic UV stabilizer.