Patent ID: 7858543

Claim:
A resin joined body comprising: at least one member comprising a first resin layer and a second resin layer wherein at least one of the first resin layer and the second resin layer is a nonwoven fabric formed of aramid fiber, said first resin layer and said second resin layer being held in surface-to-surface contact with each other to form a joined portion, said joined portion having a fuse bonded portion formed by fuse bonding of the resin material, wherein the resin joined body is obtained by holding the first resin layer and the second resin layer in surface-to-surface contact with each other, irradiating a laser beam from a rear side of at least one of the first and second resin layers to said surface-to-surface contact portion, and irradiating the laser beam so as to be focused during the travelling from said rear side to a front side of said at least one of the first and second resin layers so that the resin material on the front side is heat fused to form said fuse bonded portion, wherein said at least one of the first and second resin layers having the rear side from which the laser beam has been irradiated has an absorption constant of 50 to 5000 m −1 for the wavelength of the laser beam, and the fuse bonded portion is formed to have a relationship of X>Y, wherein a light transmittance of light passing from the first resin layer to the second resin layer via the fused portion is designated as X(%), and a light transmittance of light passing continuously from the first resin layer to the second resin layer via a portion other than the fused portion is designated as Y(%).