METHOD FOR BONDING THERMOPLASTIC SHEET AND HEATING DEVICE FOR BONDING

摘要

PROBLEM TO BE SOLVED: To avoid step difference of the whole bonded part and to make it uniform and to make no decrease in strength of a sheet by a method wherein the bonding parts are heated in such a way that the center in the width direction of a heating and pressing part is made to be a high temp. where a thermoplastic sheet melts but does not thermally decompose and both end parts in the width direction is made to be a low temp. where the thermoplastic sheet does not melt. SOLUTION: Electricity is passed through a rod-like heater 13 and it is heated to control and hold the central part in the axial direction of a face heater 18a at a required high temp. and on the other hand, cooling water is simultaneously passed through a cooling pipe 16 to hold the neighborhood of the end part of the face heater 18a at a lower temp. than the central part and a heating part with such a definite temp. profile that has a temp. gradient in the width direction in a heating and pressing part can be obtd. thereby. Heat bonding of a joint can be performed thereby by holding a temp. profile with a temp. gradient in the width direction in such a way that the central part in the width direction has a definite temp. at a high temp. side within a range where the thermoplastic sheet melts but does not decompose and both end parts in the width direction has a definite temp. at a low temp. side where the thermoplastic sheet does not melt.