Corrosion problems in tinplate cans for storing contact glues for shoes

Tinplate steel cans were used to store contact glue for shoes. A few months after its storage, the glue displayed a change in colour to a darker brown. The visual inspection of the interior of the cans showed the presence of corrosion of steel, which was evidenced by the typical colour of the iron oxides on the sheet. SEM/EDS and FTIR tests confirmed that the anomaly was due to the following factors: (a) a bad tin coating, small thickness and lack of homogeneity; (b) a degradation of glue, hydrolysis of chloroprene, which led to its acidification. Some recommendations are made to overcome similar situations within the same use of these packages looking at the specifications of tinplate.

Figure optionsDownload as PowerPoint slideHighlights
► Corrosion in tinplate cans is investigated.
► Acidification of the glue as a result of hydrolysis of polychloroprene increases the corrosion.
► A mechanism that explains the appearance of galvanic coupling between the tin and iron is introduced.
► It is suggested to use a thicker coating of tin with a passivation treatment and finishing lacquer.