The Removal Torque Increment on Metal Cans Containing an Asphaltic Pruning Seal Compound


A study of cap removal torque of a 16 fl.oz. electrolytic tin plate (ETP) container and closure with continuous threads as well as a 0.04 inch polyethylene (PE) liner was conducted. These packages contain a solvent asphaltic pruning seal product. At room temperature the removal torque behaviour was investigated using ETP cans with and without the product at intervals of logarithmic decades of time in days. A SWAN‐MATIC capping machine was utilized to provide predetermined application torques of 20, 30 and 40 in. lbs at 90d̀, 80d̀ and 70d̀ angles of application. The removal torque of each experimental test was measured by hand using the SECURE PAK tester machine, which provided a maximum torque reading accuracy of up to a tenth of a unit. The study revealed that ETP containers with PE‐lined ETP caps, uncontaminated with the product, exhibited logarithmic removal torque decay. However, the ETP container with the asphaltic pruning seal product spilled on the top and threads of the closure showed an increasing trend of removal torque. This occurrence was probably caused by the adhesive effect of the product at the closure. Copyright © 1995 John Wiley & Sons, Ltd


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Cap removal torque; ETP cans; PE liners

International Standard Serial Number (ISSN)

1099-1522; 0894-3214

Document Type

Article - Journal

Document Version


File Type





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Publication Date

01 Jan 1995