| abstract |
The invention relates to a method for welding at least two plastics, in which the process energy required for welding is laser light energy, and which is characterized in that auxiliary energy is supplied to the joining area, that particles of at least one substance A¶j¶ present in the joining area due to the auxiliary energy. are reversibly converted into one or more substances B¶i¶, the substance or substances B¶i¶ in their entirety absorbing the laser radiation more than the substance A. Furthermore, the invention relates to a plastic and a welding filler material, each of which has at least one substance A ¶J¶ contained, which can be reversibly converted into one or more substances B¶i¶ by supplying energy, the substance or substances B¶i¶ in their entirety absorbing the radiation in the wavelength range of 800-2000 nm more strongly than substance A ¶J¶. The invention can always be used with advantage when plastics have to be welded which are largely transparent to visible light and which do not or only weakly absorb infrared light. With these plastics, the general aim is to avoid the color change caused by the welding process. Such requirements exist in the packaging, fashion, automotive and electronics industries as well as in the fashion industry. |