TMCD-EG Polyester Shrink Films for Controlled Orientation
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Solution Overview
Problem
Existing polyester films struggle with fracturing, wrinkling, bubbling, and other issues during orientation, and lack desirable properties such as high shrink activation temperature, controlled shrinkage, and film toughness.
Innovation Solution
A polyester composition comprising terephthalic acid, 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), and ethylene glycol, with specific mole percentages and catalysts like titanium and phosphorus, is used to create oriented and shrink films with improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyester films are made with conventional compositions, then they can be manufactured with standard properties, but they fracture, wrinkle, and bubble during orientation processing
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyester by incorporating specific comonomers (cyclohexanedimethanol, neopentyl glycol, diethylene glycol) in controlled amounts to achieve optimal melt viscosity and molecular weight distribution, enabling successful orientation without fracturing
Solution Approach 2:
The patent creates a composite polyester material combining multiple diol components (TMCD, EG, CHDM, NPG, DEG) with terephthalic acid in specific ratios to achieve a balanced combination of mechanical properties, processability, and orientation stability
2Temperature
If polyester composition is modified to improve shrinkage properties, then shrink activation temperature increases, but film toughness decreases
Solution Approach 1:
The patent adjusts the molecular weight and comonomer ratios to fine-tune the glass transition temperature and crystallization behavior, achieving higher shrink activation temperature while maintaining film toughness through optimized composition
Solution Approach 2:
The patent introduces different diol components with specific functions: TMCD for high-temperature stability, CHDM for crystallinity control, and NPG/DEG for toughness enhancement, creating localized functional properties within the polymer structure
3Force
If polyester films are oriented to achieve high shrinkage, then shrink force increases, but the film fractures and breaks
Solution Approach 1:
The patent performs preliminary orientation at controlled temperatures and rates to establish a stable molecular structure before final shrinkage, preventing fracture during high-force shrinkage operations
Solution Approach 2:
The patent optimizes the molecular weight distribution and comonomer composition to achieve optimal melt viscosity that allows dynamic adjustment during orientation and shrinkage processes, maintaining film integrity under varying stress conditions
Data Source
Figure 1~2
AI summary
This invention relates to an oriented film or a shrink film comprising a polyester composition comprising: (1 ) at least one polyester which comprises: (a) a dicarboxylic acid component comprising: (i) about 90 to about 100 mole % of terephthalic acid residues; (ii) about 0 to about 10 mole % of aromatic and/or aliphatic dicarboxylic acid residues having up to 20 carbon atoms; and (b) a glycol component comprising: (i) about 10 to about 29 mole % 2,2,4,4-tetramethyl-1,3- cyclobutanediol residues; and (ii) about 71 to about 90 mole % ethylene glycol residues; and (iii) optionally, diethylene glycol residues; wherein the total mole % of the dicarboxylic acid component is 100 mole %, and wherein the total mole % of the glycol component is 100 mole %; wherein the inherent viscosity of the polyester is from 0.50 to 0.8 dL/g as determined in 60/40 (wt/wt) phenol/ tetrachloroethane at a concentration of 0.25 g/50 ml at 25°C; wherein the polyester has a Tg of from 80 °C to 105 °C or of from 80 °C to 100 °C as determined using a TA DSC 2920 from Thermal Analyst Instrument at a scan rate of 20 °C/min.; and (2) optionally, wherein the polyester composition comprises at least one plasticizer.