PURPOSE: To obtain a flexible tube having excellent chemical resistance, heat resistance, airtightness, bending resistance, etc., by integrating a first layer made of polytetrafluoriethylene having a solid structure and a second layer made of a tube having a porous structure of the same product by thermal fusion bonding, and setting the thickness of the first layer to a specific range of the total of both the layers.
CONSTITUTION: This flexible multilayer tube comprises a first layer of polytetrafluoroethylene having a solid structure and a second layer of a porous structure of polytetrafluoroethyelene covering the outer periphery of the first layer in such a manner that the first and second layers are integrated by thermal fusion bonding, the thickness of the first layer is in a range of 1/1000 to 1/2 of the total thickness of both the layers or preferably 1/100 to 1/2 of the thickness ratio. If the ratio exceeds 1/2, the obtained tube is easily broken. On the other hand, if it is smaller than 1/1000, it becomes excessively thin to the thickness of the first layer of the tube, and hence in the case of using the multilayer tube, the first layer is easily broken.
URAGAMI SHINICHI
NAKAJIMA TOSHIYUKI
ARAI KEIICHI
OLYMPUS OPTICAL CO
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