Biaxially Oriented Polyester Film Surface Roughness Control
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Solution Overview
Problem
Biaxially oriented polyester films face issues with mechanical properties, transparency, heat resistance, secondary processing suitability, and printing appearance due to surface roughness and agglomeration of inorganic particles, which affect handling and printing quality.
Innovation Solution
A biaxially oriented polyester film with specific surface roughness and inorganic particle distribution, comprising a polyethylene terephthalate-based resin and silica particles, is produced through a method involving multiple extrusion and stretching processes to achieve optimal mechanical properties and printing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If inorganic particles are added to improve surface roughness for handling, then sliding performance and crinkle reduction are improved, but printing appearance deteriorates due to missing printing
Solution Approach 1:
The patent changes the particle size parameter from conventional large particles (10 μm or more) to fine particles (0.5 μm to 3.0 μm). This parameter change allows the inorganic particles to provide sufficient surface roughness for improved sliding performance and crinkle reduction while being small enough to avoid causing missing printing, thus resolving the contradiction between handling ease and printing appearance.
Solution Approach 2:
The patent applies local quality by creating a dual-layer structure where the surface layer contains fine inorganic particles (0.5 μm to 3.0 μm) for printing quality, while the inner layer contains both fine and coarse particles for bulk mechanical properties. This local differentiation allows each layer to optimize for its specific function, resolving the contradiction between surface printing appearance and overall handling performance.
2Ease of operation
If high concentration of inorganic particles is used to improve surface roughness, then handling properties are improved, but particle agglomeration occurs leading to further printing defects
Solution Approach 1:
The patent changes the particle size parameter to fine particles (0.5 μm to 3.0 μm) which have smaller dimensions and lower tendency to agglomerate. This parameter change allows achieving the desired surface roughness and handling properties at lower particle concentrations, preventing agglomeration-related printing defects while maintaining improved handling characteristics.
Solution Approach 2:
The patent uses composite materials by combining fine inorganic particles (0.5 μm to 3.0 μm) with the polyester resin matrix. This composite approach allows the fine particles to be uniformly distributed throughout the resin without agglomeration, providing sufficient surface roughness for handling improvement while maintaining printing quality through uniform dispersion.
3Ease of operation
If coarse particles are used to provide surface roughness, then handling performance is improved, but transparency and mechanical properties deteriorate
Solution Approach 1:
The patent changes the particle size parameter from coarse particles (10 μm or more) to fine particles (0.5 μm to 3.0 μm). This parameter change reduces light scattering effects that cause transparency deterioration while still providing sufficient surface roughness for improved handling performance, thus resolving the contradiction between handling performance and transparency.
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 exhibits superior mechanical properties, transparency, heat resistance, and improved secondary processing and printing appearance, reducing crinkles and agglomeration issues, while allowing for high content ratios of economical and recycled resins.
Implementation Method 1
a method in which fine protrusions are formed on a surface of a polyester film is used
Implementation Method 2
a biaxially stretched PET film has good balance between costs and mechanical strength, heat resistance, dimension stability
Implementation Method 3
biaxially oriented polyester film
Data Source
AI summary
The present invention is to provide a method for producing a biaxially oriented polyester film that is superior in mechanical properties, transparency, and heat resistance, and at the same time, superior in secondary processing suitability and printing appearance. Disclosed is a biaxially oriented polyester film, having at least one surface satisfying the following requirements (1) and (2), and the film satisfying the following requirements (3) and (4). (1) A maximum peak height roughness (SRp) is 1.2 μm to 1.6 μm. (2) An arithmetic average roughness (SRa) is 0.024 μm to 0.045 μm. (3) A tensile strength in a longitudinal direction and a width direction is 180 MPa to 300 MPa. (4) A haze is 7% or less.