Progress in materials for can stock and future trends.

Abstract

Developments in electrolytic tin plate, tin-free steel and more recent low tin materials are described with emphasis on their corrosion performance and their applicability to the newer can manufacturing processes. The significance of tinplate special property tests and their relative importance are discussed as related to corrosion performance in cans for moderate to high corrosivity food products. Information regarding pitting corrosion of aluminum killed continuous cast tinplate in cans for light colored fruits is also reviewed. Tin-free and low tin materials are being used in drawn and welded cans, but better enamel coverage is required than for tinplate cans. Long term trends show that aluminum has taken over most of the beer and soft drink market but its use in food cans remains very limited. New processable multilayer plastic barrier materials have been introduced as cans, bowls and trays for single serving microwaveable foods, which could have a significant impact on metal cans. The solid waste issue and recyclability of the various materials is discussed. A new process for improving the quality of shelf stable processed foods is also described.