同時二軸延伸ナイロン・フイルムの溶接性に関する研究

抄録

The purpose of this paper is to clarify the characteristic of simultaneous two-axis drawing nylon film and seek after the possibilities of welding bond, making use of the property of thermoplastics. Namely molecular chain oriented by simultaneous two-axis drawing is considered to be set at random by welding, which causes a great property change on both weld and heat affected zone, and thus the characteristic of simultaneous two-axis drawing nylon film can be considered to be done away with. The focus of the study, therefore, is to ob-tain the welding conditions without losing the characteristic of simultaneous two-axis drawing nylon film. Welding method used is heating plate welding and suitable conditions are established by studying the in-terrelation among heating plate shape, heating temperature, welding pressure and welding time. Specimen used was simultaneous two-axis drawing 6-nylon film, 0.025 mm in thickness. First, tensile strength and elongation were recorded from tension tests in machine direction (M.D.), transverse direction (T.D.), and a 45-degree angle direction, and microstructure was examined by X-ray diffraction. Specimen used in the tension test was JIS K6475 type-3 dumb-bell type. The suitable voltage for the desired heating temperature is obtained from A.C. 100 V regulated by slidac, and the temperature was measured from heating plate by thermocouple. Welding pressure was applied based on lever principle and was pricked up by compression load cell and then put into tensilon recorder. The pressure was applied quickly, and welding time was recorded just after necessary pressure being obtained. Both up and down sides of specimen surface were covered with 0.18 mm teflon film mixed with glass cloth to make me specimen stick to neither heating plate nor rubber plate. Specimen was preheated just before the experiment in the hot air circulating dryer at 50°C for 25hr. for the sake of getting better conditions. Bubbles born at welding time are thus avoided. Heating plate attached to the welding apparatus is made of copper, and 3 different types in shape are shown in fig. 1. Type I is for peeling the specimen, type 2 is for manufacturing the tensile specimen, type 3 is for inspecting the differences of joint efficiency resuting from the variouss hapes of heating plate. Changes of microstructure caused by influences described above were examined by studying the orientation changes obtained from comparison of diffraction degree of X-ray diffraction photographs taken on plain films, by penetration method. In case of 6-nylon, diffraction patterns of (200) (002) side are observed to be relatively strong. X-ray test conditions are as follows. Voltage:55 KV, electric current:10m A, distance between specimens :28 mm, irradiation time:2 hr, X-ray apparatus: SHIMAZU analysis type X-ray apparatus GX-1. The following conclusion can be made from the results of the present experiments. Welding of simultaneous two-axis drawing nylon film is possible without losing its characteristic, by choosing the proper welding conditions.