Multilayer Polyester Film with Organic Slip Additives for Metal Lamination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The poor winding and handling of thin polyester films during lamination to metal substrates, which often result in defects such as wrinkles, creases, and air bubbles, due to high friction and adherence between film layers, and the drawbacks of using particulate anti-blocking agents, including equipment damage and variability in film properties.
Innovation Solution
A multilayered polyester film structure with organic slip additives in the skin layers, free from insoluble particulates, to reduce friction and improve slipperiness, while maintaining adhesion and formability, and the use of a heat treatment to enhance corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thin polyester films are wound into coils for lamination to metal substrates, then the films can be handled and processed, but poor winding behavior generates web breaks, folds, wrinkles and creases due to high friction and adherence between adjacent film layers
Solution Approach 1:
An outer skin layer acts as an intermediary between the core layer and adjacent film layers during winding. This skin layer contains slip additives that reduce friction and adherence, preventing direct contact and high friction between the core layer and other layers, thereby eliminating wrinkles and folds while maintaining handling ease
Solution Approach 2:
The friction coefficient between film layers is modified by adding slip additives (such as waxes or fatty acid esters) to the outer skin layer. This changes the surface properties of the film layers, reducing the coefficient of friction from a high value that causes adherence to a low value that enables smooth winding and handling without defects
2Ease of operation
If particulate anti-blocking agents are used to reduce friction between film layers, then winding properties improve, but equipment damage occurs and film properties show variability
Solution Approach 1:
The patent replaces durable inorganic particulates with organic slip additives that are applied in small amounts and can be easily replenished. These organic additives provide the necessary slip properties without the hardness and abrasiveness of inorganic particles, eliminating equipment damage while maintaining consistent film properties through controlled addition
Solution Approach 2:
The invention changes the type of friction-reducing agent from inorganic particulates to organic slip additives. This parameter change in the chemical composition and physical state of the additive eliminates the harmful effects of hard particles on equipment while providing reliable, consistent slip properties that reduce variability in film characteristics
3Reliability
If a polyester film is laminated to a metal substrate for can manufacturing, then corrosion protection and printability are provided, but poor winding behavior causes defects such as air bubbles and blisters in the final product
Solution Approach 1:
The outer skin layer with slip additives serves as a mediator that prevents adhesion between stacked film layers during winding and handling. This eliminates air pockets and voids that would otherwise be trapped between layers, ensuring a defect-free laminate free from air bubbles and blisters while maintaining the corrosion protection function of the polyester film
Solution Approach 2:
The slip additives are incorporated into the outer skin layer during film production, preliminarily preparing the film surface to prevent adherence before the lamination process. This preliminary anti-adhesion treatment ensures that when multiple layers are wound and subsequently laminated to the metal substrate, they remain properly separated and aligned, preventing the formation of defects
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 solution significantly improves the winding and handling of polyester films, enhances film adhesion to metal substrates, and provides excellent corrosion resistance and formability, with improved performance in can manufacturing, particularly during sterilization, by reducing scuffing and porosity.
Implementation Method 1
Another well-known method for reducing friction between film layers is based on the use of so-called slip additives, which reduce the coefficient of friction
Implementation Method 2
the use of a heat treatment to enhance corrosion resistance
Data Source
Figure 1
AI summary
Laminate comprising a metal substrate provided with an as cast and subsequently machine direction orientated polyester film laminated on at least one face of the metal substrate the polyester film having a multilayered structure comprising a polyester core and two polyester skin layers, for laminating to a metal substrate, wherein the polyester skin layers each comprise an organic slip additive and wherein the polyester skin layers are free from inorganic particulates that are insoluble in the polyester matrix of the respective skin layer,wherein the amount of slip additive in each skin layer is above 1500 ppm and below 10000 ppm.