MDO Thermoresistant Copolymer Polyester Film

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Solution Overview

Problem

Conventional heat-shrinkable films face issues with thermal resistance, storage stability, and complex production processes, leading to deformation and inefficiencies in labeling and packaging applications, particularly when exposed to high temperatures.

Innovation Solution

A copolymer polyester MDO heat-shrinkable film with a molecular weight of 18,000 g/mol or more, composed of terephthalic acid and a diol component including isosorbide and 1,4-cyclohexanedimethanol, optimized for machine direction orientation, offering improved thermal resistance and simplified production processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If TDO (transverse direction orientation) method is used to produce heat-shrinkable film, then the film can be produced with conventional processes, but the production process becomes complicated requiring primary slitting, printing, secondary slitting, seaming or sealing, labeling, etc.

Engineering Contradiction:
Improveproduction process simplicityVSAvoidprocess complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent inverts the conventional TDO approach by using MDO (machine direction orientation) instead. Rather than orienting the film in the transverse direction and then performing multiple post-processing steps, the invention orients the film in the machine direction during extrusion, eliminating the need for primary slitting, secondary slitting, seaming, and other complicated post-processing operations.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of manufacture

If processing temperature when printing is high, then printing can be completed, but shrinkage and deformation are generated in the shrink label causing it to be crooked unlike the intended form

Engineering Contradiction:
Improveprinting completionVSAvoidlabel shape accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent modifies the thermal parameters of the polyester resin by incorporating specific diol components (1,4-cyclohexanedimethanol and isosorbide) in controlled ratios. This changes the glass transition temperature and thermal behavior of the material, allowing the film to maintain dimensional stability at printing temperatures while still achieving the required shrinkage properties at lower temperatures, thus preventing deformation during the printing process.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional polyester resin is used for heat-shrinkable film, then the film can be produced, but thermal resistance is insufficient causing deformation when exposed to heat such as high temperature beverage injection

Engineering Contradiction:
Improvefilm productionVSAvoidthermal resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent creates a composite polyester resin system by combining terephthalic acid with specific diol components (1,4-cyclohexanedimethanol and isosorbide) in optimized ratios. This composite material structure provides enhanced thermal resistance and dimensional stability compared to conventional polyester resins, while maintaining the heat-shrinkable properties necessary for label applications.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If polyvinylchloride film is used for labels and packaging, then the film can be produced and used, but hydrogen chloride gas and dioxin-causing materials are generated during incineration

Engineering Contradiction:
Improvefilm productionVSAvoidharmful gas emission
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent fundamentally changes the chemical composition parameter of the film material by replacing polyvinylchloride with a polyester resin system. This material substitution eliminates the generation of hydrogen chloride gas and dioxin-causing materials during incineration, while maintaining the necessary film production capabilities and heat-shrinkable properties for label and packaging applications.

Inventive Principle:
Principle #35Parameter changes

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 excellent thermal resistance with maximum shrinkage of 30% to 65% at 100°C, reduced deformation at high temperatures, and streamlined production, enhancing its suitability for labels and packaging without the need for separate slitting or direction changes.

Implementation Method 1

formed by copolymerization of an acid component including terephthalic acid and a diol component

Methodology Applied
Scientific EffectCopolymerization:

Implementation Method 2

Heat-shrinkable plastic products use heat-shrink properties... the maximum heat shrinkage at 95 to 100° C. of 30% to 65%

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 3

heat-shrinkable films are produced by TDO (transverse direction orientation)... introduced in the upper and lower direction of the container and attached, and then passed through a heat-shrink tunnel

Methodology Applied
Scientific EffectStress relaxation: Stress Relaxation

Data Source

PatentUS11560457B2MDO thermoresistant heat-shrinkable film
Publication Date: 2023.01.24 SK CHEMICALS CO LTD

AI summary

The present invention relates to an MDO heat-shrinkable film of a copolymer polyester having excellent thermal resistance. In particular, the present invention provides a copolymer polyester MDO (machine direction orientation) thermoresistant heat-shrinkable film that consists of a copolymer polyester resin including isosorbide and 1,4-cyclohexanedimethanol at an optimized content ratio as a diol component copolymerized with an acid component including terephthalic acid, and having a number average molecular weight of 18,000 g/mol or more, and can be used for labels, cap seals, direct packaging, etc. of various containers due to the high shrink initiation temperature.