White Microvoided Polyester Film Opacity and Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-transparent microvoided axially stretched films suffer from insufficient opacity, dimensional instability, and inadequate whiteness, which limits their applications.
Innovation Solution
Incorporating small quantities of inorganic opacifying pigments and adjusting the polyester matrix composition, along with lower stretching temperatures, to enhance opacity and dimensional stability, while using a non-crosslinked random SAN-polymer and specific monomer units in the film production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stretching temperatures are used for polyester films, then dimensional stability is achieved, but opacity is lost during thermal fixation
Solution Approach 1:
The patent applies parameter changes by reducing the stretching temperature to below the conventional range for polyester films. This temperature modification allows the film to achieve both dimensional stability and maintain opacity during thermal fixation, resolving the contradiction between these two properties that normally require high temperature processing
Solution Approach 2:
The patent uses composite materials by incorporating inorganic opacifying pigments into the polyester matrix. This composite structure enables the film to maintain opacity while achieving dimensional stability at lower temperatures, as the inorganic pigment particles provide both opacification and thermal stability without requiring high-temperature processing
2Illumination intensity
If inorganic opacifying pigments are added to enhance opacity, then opacity and whiteness improve, but manufacturing complexity increases
Solution Approach 1:
The patent modifies the manufacturing process parameters by using lower stretching temperatures and simplified processing conditions when incorporating inorganic pigments. This parameter optimization reduces manufacturing complexity despite the addition of pigment materials, as it avoids the need for complex high-temperature processing equipment and multi-step procedures
3Strength
If high stretching ratios are applied to achieve film orientation, then mechanical strength improves, but microvoid structure is damaged and opacity is reduced
Solution Approach 1:
The patent changes the temperature parameter during stretching to a lower range that preserves the microvoid structure while still achieving adequate film orientation and mechanical strength. This temperature modification allows the formation of microvoids that maintain opacity without requiring extremely high stretching ratios that would collapse the void structure
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 approach results in improved opacity and dimensional stability at lower thermal fixation temperatures, enabling the production of a white, microvoided, non-transparent film suitable for various applications, including synthetic paper and image recording elements.
Implementation Method 1
Incorporating small quantities of inorganic opacifying pigments... to enhance opacity
Implementation Method 2
a continuous phase linear polyester matrix having dispersed therein a non-crosslinked random SAN-polymer... microvoided
Implementation Method 3
lower stretching temperatures... lower thermal fixation temperatures
Data Source
AI summary
Disclosed is a process for preparing a non-transparent microvoided axially stretched film including i) mixing a linear polyester having monomer components consisting essentially of an aromatic dicarboxylic acid, an aliphatic diol and optionally an aliphatic dicarboxylic acid, a non-crosslinked random SAN-polymer and one or more additional ingredients to produce a mixture, ii) forming the mixture produced in step i) in a thick film followed by quenching; iii) stretching the thick film at a temperature between the glass transition temperature of the SAN-polymer and the glass transition temperature of said linear polyester to at least twice the initial length, and (iv) further stretching the film at an angle substantially 90° to the previous stretching process to at least twice the initial length and at 90° C. or below.