Colored thermoplastic resin compositions for laser welding, specific neutral anthraquinone dyes as colorants therefor, and molded product therefrom

1. A thermoplastic resin composition for laser welding comprising:

1) thermoplastic resin; and,

2) a laser transmitting black colorant comprising a mixture of a) neutral anthraquinone dye which imparts colors of blue, violet or green, absorbs visible light with wavelength less than 700 nm and transmits a laser beam with wavelength at 800 nm to 1200 nm in the infra-red region with b) at least one other red dye which transmits with a wavelength at 800 nm to 1200 nm in infra-red region, selected from the group consisting of perinone dyes monoazo complex dyes and anthraquinone dyes.

2. The thermoplastic resin composition of claim 1 wherein said colorant comprises a mixture of said neutral anthraquinone blue dyes with said red dyes and further other yellow dyes.

3. The thermoplastic resin composition of claim 1 wherein said thermoplastic resin is polyamide or polyester.

4. The thermoplastic resin composition of claim 1 further comprising reinforcing agent.

5. A laser-transmitting article formed from the composition of claim 1 .

6. An article formed by laser welding a laser-absorbing article with the laser-transmitting article of claim 5 .

7. A laser-transmitting black colorant suitable for being mixed with a thermoplastic resin applied to a laser welding comprising a mixture of a) neutral anthraquinone dye which imparts colors of blue, violet or green, absorbs visible light with wavelength less than 700 nm and transmits a laser beam with wavelength at 800 nm to 1200 nm in mire-red region with b) at least other red dye which transmits the laser beam with wavelength at 800 nm to 1200 nm in infra-red region, selected from the group consisting of perinone dyes, monoazo complex dyes and anthraquinone dyes.

8. The laser-transmitting black colorant of claim 7 comprising said mixture of neutral anthraquinone blue dyes with red dyes and further yellow dyes.