Toyo Seikan Kaisha, Ltd.

Toray Industries, Inc.

Yukio Suzuki

Michiko Tsurumaru

Hiroshi Ueno

Masanori Aizawa

Hiroshi Matsubayashi

Shinya Otsuka

Hiroki Sano

Masato Ashina

Atsushi Nunokawa

Fumihiro Tsutsumi

Hironori Kobayashi

Disclosed is a method for measuring the metal exposure in a resin covering area of a metal container or a constituent member thereof, which comprises contacting the resin covering area of the metal container or the constituent member thereof with a measuring electrode through an electrolytic solution, relatively moving the resin covering area and the measuring electrode in a certain direction while always holding the electrolytic solution between the measuring electrode and the resin covering area, measuring a leak current between the metal substrate of the metal container or constituent member at predetermined pitches and detecting the metal exposure of the resin covering area as leak currents at respective parts discriminately. According to this measuring method, the degree of the metal exposure can be easily measured as the leak current at respective parts discriminately, and statistical processing of the measured leak current values can be easily performed.

Method and apparatus for measuring metal exposure in resin covering

Disclosed is a method for assaying an iron-exposed portion of a coated steel plate or a processed product thereof, which comprises bringing a surface, to be measured, of the coated steel plate or processed product thereof, a reference electrode and a counter electrode into contact with a buffer solution having a pH value of from 9.0 to 11.0, effecting in this state electrolysis between the counter electrode and the coated steel plate or processed product thereof under such conditions that the voltage of the coated steel plate or processed product thereof to the reference electrode is 0.8 to 1.5 volts as calculated as a saturated calomel electrode, and evaluating the iron-exposed portion by measuring an electric current flowing between the counter electrode and the coated steel plate or processed product thereof or by observing precipitation and deposition of an oxide or hydrated oxide of iron. According to this method, an iron-exposed portion of a coated steel plate or a processed product thereof can selectively be detected and assayed and evaluated precisely without any substantial influence on a metal present as the coating layer very easily by using a simple measurement apparatus. The results obtained according to this method are well in agreement with the results of the actual test made on cans or other processed products of the coated steel plate.

Method for assaying iron-exposed portion of coated steel plate or

In a coated metal structure comprising a metal substrate and a coating layer of a thermoplastic polyester resin heat-bonded to the metal surface, the polyester resin has a relative viscosity of 1.2 to 1.8 as measured at 25.degree. C. in o-chlorophenol at a concentration of 0.5 g/100 ml and the tack point of the polyester resin is not lower than 130.degree. C. and the degree of crystallinity of the polyester resin is up to 30%. This structure has improved peel resistance and is excellent in mechanical and chemical properties, especially adaptability to shaping processing and corrosion resistance. This structure can easily be formed into various vessels and containers and closure means of vessels and containers by such processing as drawing and ironing. This structure provides shaped articles excellent in peel resistance, corrosion resistance and processability.

Coated metal structure and process for production thereof

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Kawasaki, Japan

Yukio Suzuki