E-Thesis 224 views 267 downloads
The Adhesion of Protective Coatings to Novel REACH Compliant Packaging Steel Substrates / MATTHEW DODD
Swansea University Author: MATTHEW DODD
DOI (Published version): 10.23889/SUthesis.64830
Abstract
Chromium coated packaging steel substrates are used in applications which require a lacquer coating which insulates the can and cans contents form each other. Legislative pressures in Europe defined by REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) have dictated the rem...
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Swansea, Wales, UK
2023
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| Institution: | Swansea University |
| Degree level: | Doctoral |
| Degree name: | EngD |
| Supervisor: | Jewell, Eifion., Wint, Natalie., de-Vooys, Arnoud. and Edy, James. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa64830 |
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| Abstract: |
Chromium coated packaging steel substrates are used in applications which require a lacquer coating which insulates the can and cans contents form each other. Legislative pressures in Europe defined by REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) have dictated the removal of Cr (VI) from the electrocoating process of these packaging steel substrates, as well as restricting the use of bisphenol-A (BPA) used in protective lacquers. Both chemicals have been shown to pose significant safety risks due to their inherent toxicity to humans and the environment. Cr (III) electrocoating’s have since been investigated as a replacement but are, as yet, in their commercial infancy. One such material is TCCT (Trivalent Chromium Coated Technology) which is produced by TATA Steel Europe. In addition, lacquers have been developed to which bisphenol-A has not intentionally been added (BPANI) satisfying both REACH legislation and a consumer dictated move away from BPA. The combination of these two novel technologies enables conformity to legislative pressures. The work presented in this thesis reports an investigation into the physical and chemical characteristics of TCCT packaging steel substrates, specifically looking at the effect of chromium oxide coating weight. An established methodology is used to investigate the adhesive performance of both epoxy based and BPANI lacquers to TCCT before and after a retort process, which is used to simulate industrial pressure cooking conditions. Comparisons are made to commercially mature substrate materials. The TCCT manufacturing process is replicated on a laboratory scale with view to validating a self-sufficient process of sample creation. The effect of various electroplating parameters such as applied current density, electrolysis time, pulsing, temperature and pH are investigated. These samples are characterised using a consistent methodology. This consists of surface topographical analysis, visual analysis using electron microscopy and a copper sulphate dip test. These techniques showed the similar visual characteristics of industrially made and laboratory made TCCT samples but highlighted a more inconsistent coating deposited on the laboratory made samples. |
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| Keywords: |
Steel, Packaging, Adhesion, Chromium, Electrodeposition |
| College: |
Faculty of Science and Engineering |
| Funders: |
EPSRC doctoral training grant, WEFO, TATA Steel |