Toyo Seikan Kaisha, Ltd.

Toray Industries, Inc.

Michiko Tsurumaru

Hiroshi Ueno

Hiroshi Matsubayashi

Yukio Suzuki

Atsushi Nunokawa

Seishichi Kobayashi

Seiichi Nakazato

Masanori Aizawa

Yoichi Kitamura

Shinya Otsuka

Makoto Horiguchi

Hiroki Sano

Masato Ashina

Masatsune Shibue

Kazuhisa Masuda

Hironori Kobayashi

Fumihiro Tsutsumi

A metal can body of improved impact resistance of the body wall is formed by drawing and/or pressing subsequent to preliminary coating of an organic resin on at least one side of the metal surface that becomes the inner surface of the can body. The main component of the organic resin coating is a polyester resin containing oriented crystals. The intrinsic viscosity (IV) of the polyester layer is 0.60 or higher. Parameter A representing the ratio of axial orientation in the direction of the can height is A.gtoreq.0.40. and Parameter B representing the degree of plane orientation of axially oriented crystals in the direction of the can height is B.gtoreq.0.00.

Can body having improved impact

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 bonded can of the key-opening type comprising a coated metal blank and a seam formed by lap-bonding outer and inner end edge portions of the coated metal blank to each other by a tape of a thermoplastic resin adhesive, wherein the adhesive is a polyamide type or polyester type adhesive, the inner end edge portion forming the seam of the bonded can is completely covered with the adhesive tape, the outer edge portion has a winding-starting tongue piece integrated therewith, a plurality of scores are formed on the outer surface of the coated metal blank from the base of the tongue piece along the entire circumference inclusive of the seam, the scores have a knife angle of 45.degree. to 120.degree. and a depth corresponding to 8 to 45% of the thickness of the metal blank, a coating of an epoxy resin having a thermal softening point of 65.degree. to 150.degree. C. as measured according to the thermomechanical method is formed at least at the seam-forming part on the outer surface and said epoxy resin coating forms a continuous layer adhering closely to the metal blank even in the portion of said scores.

Process for production of bonded can of key-opening type

Bonded can of key-opening type and process for production thereof

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

A can at least a part of which is made of an electrolytically chromated steel sheet, said steel sheet having such a surface that when it is degreased in acetone for 1 minute and analyzed by an Auger electron spectrometer at an incident electron accelerating voltage of 3 KeV, a modulation voltage of 3 V, a modulation frequency of 12 to 20 KHz and a degree of vacuum of at least 6.times.10.sup.-8 torr, the ratio of the peak-peak distance (O.sub.P-P) of KL.sub.2.3 L.sub.2.3 of oxygen to the base-peak distance (Cr.sub.B-P) of L.sub.3 M.sub.2.3 M.sub.4.5 of chromium in the resulting Auger electron spectrum satisfies the following relation:

Can composed of electrolytically chromated steel

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

Growing community of inventors

Tokyo, Japan

Michiko Tsurumaru