Marked thermoplastic compositions, methods of making and articles comprising the same, and uses thereof

A method of forming an article with a dark laser mark and a light mark, comprising:

• locating a layer C between a layer E and a layer A;
• and
• directing a laser light having a wavelength of less than or equal to 500 nanometers at a layer E to increase reflectivity of an area contacted by the laser light and to form the light mark;
• and
• forming the dark laser mark in layer C, wherein the dark laser mark has an L* of less than or equal to 40 as measured according to CIELAB 1976 (specular included);
• wherein the layer A has a visible transmission of greater than or equal to 80% according to ASTM D1003-00, Procedure A, using D65 illumination, 10 degrees observer, at a thickness of the layer A in the article;
• wherein the layer E comprises a thermoplastic composition capable of absorbing light having a wavelength less than or equal to 500 nanometers;
• and has a visible transmission of greater than or equal to 80% according to ASTM D1003-00, Procedure A, using D65 illumination, 10 degrees observer, and at a thickness of 1 mm;
• wherein when measuring the light mark from the front side, the light mark measured from the front side has a front side mark L* measured according to CIELAB 1976 (specular included);
• wherein when measuring the light mark from the rear side, the light mark measured from the rear side has a rear side mark L* measured according to CIELAB 1976 (specular included) and a rear side average percent reflection of 11.5 to 25.3 as measured according to ASTM D1003-00 using D65 illumination and 10 degrees observer at a thickness of 1 mm;
• and
• wherein a delta between the front side mark L* and the rear side mark L* is 1 to 10.