With the new near-infrared (NIR) absorbers Lumogen® IR 788 and Lumogen® IR 765, BASF has opened the door for its customers to a completely new range of applications in the area of laser welding of plastics. The product innovations allow laser transmission welding of coloured and transparent polymers.
Until now as a general rule, carbon black has been added to the laser-absorbing plastic part as a broadband absorber for the laser energy. This greatly limits the range of colours and plastics that can be used in design.
Lumogen® IR 788 and Lumogen® IR 765 in contrast are thermostable, highly transparent NIR selective absorbers, with a small amount of own colour in the visible range and provide absorption especially tailored towards semi-conductor lasers with an emission wavelength of 808 nm. They can be used alone or in combination with other colorants in the laser-absorbing plastic part. This allows welded joints between light-coloured or even transparent mouldings.
The new NIR absorbers from BASF open up new applications. In medical technology, above all transparency and absolute toxicological safety are decisive in applications (e. g., tube joints, implants, dialysis systems). In the automobile industry (e. g., headlights, car keys, instrument panels) and in electronics (e. g., clocks, cell phones), a long service life as well as the widest possible range of attainable colors play an important role in laser transmission welding.
Apart from the new applications, there are two other aspects which are of great importance to the plastics processors. The NIR absorbers are processed in the same way as any standard additive (e. g., UV stabilizers). This means that additional investment in other processing technology is not necessary. Also, Lumogen® IR 788 and Lumogen® IR 765 are absolutely toxicologically safe.
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