Polyester Resin-Coated Can Sheet Balancing Abrasion and Paint Adhesion
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Solution Overview
Problem
Conventional resin-coated metal sheets for containers face issues with resin coating layer breakage and abrasion during high-formability can manufacturing, and inadequate adhesion with printing paint due to the presence of a lubricant component that inhibits paint adhesion and excessive bleed-out.
Innovation Solution
The resin coating layer is designed with a low degree of crystallinity, controlled by adjusting the half-width of the C=O stretching vibration peak to 24-28 cm^-1 and incorporating an organic lubricant within specific ranges, along with a controlled heat treatment to achieve a contact angle of 230-40° with diiodomethane, ensuring flexibility and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a lubricant component is added to the resin coating layer to suppress abrasion during can manufacturing, then the resin coating layer's resistance to abrasion is improved, but the adhesion of printing paint is worsened due to excessive bleed-out of the lubricant component to the surface
Solution Approach 1:
The patent applies parameter changes by precisely controlling the content of the lubricant component within 0.01-2.0 mass% and adjusting the half-width of the C=O stretching vibration peak to 24-28 cm^-1. These parameter adjustments optimize the balance between abrasion resistance and paint adhesion by preventing excessive lubricant bleed-out to the surface while maintaining sufficient lubrication during can manufacturing.
2Strength
If the resin coating layer is made more flexible to resist breakage during high-formability can manufacturing, then the resistance to breakage is improved, but the adhesion with printing paint may be worsened due to increased lubricant bleed-out
Solution Approach 1:
The patent uses parameter changes by controlling the half-width of the C=O stretching vibration peak (24-28 cm^-1) as an indicator of resin flexibility and lubricant mobility. This parameter control ensures the resin coating layer has sufficient flexibility to resist breakage during high-formability can manufacturing while limiting lubricant bleed-out to maintain paint adhesion.
3Ease of operation
If the content of lubricant component is increased to enhance surface slidability, then the resistance to abrasion is improved, but the bleed-out of lubricant component increases causing poor paint adhesion
Solution Approach 1:
The patent applies parameter changes by establishing a precise upper limit of 2.0 mass% for lubricant component content and correlating it with the half-width parameter (24-28 cm^-1). This parameter optimization ensures sufficient surface slidability for can manufacturing while preventing excessive lubricant bleed-out that would compromise paint adhesion.
Data Source
AI summary
A resin-coated metal sheet for containers includes a polyester resin coating layer on at least one side of a metal sheet. The polyester resin coating layer is such that the half-width of a peak assigned to C═O stretching vibration near 1730 cm−1 according to laser Raman spectroscopy is 24 cm−1 or more and 28 cm−1 or less as measured in such a manner that linearly polarized laser light with a wavelength of 532 nm is incident on the surface thereof in such a manner that the polarization plane is parallel to the rolling direction of the metal sheet; the polyester resin coating layer contains 0.010 mass % or more and 1.0 mass % or less of an organic lubricant.