Polyester Film Winding and Gloss via Lubricant Particle Control
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Solution Overview
Problem
Previous thermoplastic films for thermal transfer printing face difficulties in winding due to poor air exclusion performance, often resulting in wrinkles or sticking issues during high-speed winding and printing, and fail to achieve high gloss in printed images.
Innovation Solution
A thermoplastic film with a biaxially oriented polyester base layer incorporating two types of lubricant particles, which provides a smooth surface with specific roughness and friction characteristics, enabling efficient winding and high gloss printing through a sublimation type thermal transfer process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a biaxially oriented polyester film is used for thermal transfer printing, then good printing performance is achieved, but poor air exclusion performance causes winding difficulties and wrinkles
Solution Approach 1:
The invention changes the surface parameters of the polyester film by controlling the particle size distribution and content of lubricant particles. By optimizing these parameters (particle size ratio, concentration ranges), the film achieves both good printing performance and winding capability without wrinkles
Solution Approach 2:
The invention creates a composite film structure by incorporating lubricant particles (such as silicon dioxide or highly crosslinked polystyrene) into the polyester matrix. This composite approach combines the printing advantages of polyester with the surface properties needed for good winding performance
2Manufacturing precision
If a smooth surface is achieved for high gloss printing, then printing quality improves, but air exclusion performance may worsen
Solution Approach 1:
The invention applies local quality by creating a surface with controlled micro-roughness through lubricant particles. The particles are distributed to create specific surface characteristics (SRa 15-30 nm) that provide both smoothness for gloss printing and micro-features for air exclusion during winding
Solution Approach 2:
By precisely controlling the particle size ratio (3 to 15 times difference) and concentration parameters, the invention optimizes the surface morphology to simultaneously achieve high gloss for printing and adequate air exclusion for winding operations
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 achieves excellent winding capability and high gloss printing quality by maintaining a low coefficient of dynamic friction and precise surface roughness, ensuring smooth ink transfer and preventing wrinkles or sticking issues, while maintaining high gloss in all directions.
Implementation Method 1
a biaxially oriented base layer including polyester and lubricant particles
Implementation Method 2
resistive elements on the print head get heated, this causes the ink to melt
Implementation Method 3
Release happens either via ink sublimation (dye diffusion thermal transfer D2T2)
Data Source
AI summary
A substrate composite film for thermal transfer printing includes a biaxially oriented base layer including polyester, a first type of lubricant particles, and a second type of lubricant particles. The substrate composite film satisfies the following: (1) a ratio of maximum height SRma and peak count SPc is 1≦SRma/SPc≦4.5, (2) a center plane average roughness Sra is 15 to 30 nm, (3) coefficient of dynamic friction is <0.60, and (4) 20 and 60 degree gloss is greater than 160 SGU. The 20 degree gloss may be equal in all directions, and the 60 degree gloss may be equal in all directions.