The present invention provides writing compositions that are capable of being erased or changed in color chemically. The present invention also provides erasing media for erasing or changing the color of marks produced with the writing compositions, as well as writing systems and incorporating the erasing media and the writing compositions. The present invention further provides writing instruments produced using the writing compositions.

The present invention provides writing compositions that are capable of being erased or changed in color chemically. The present invention also provides erasing media for erasing or changing the color of marks produced with the writing compositions, as well as writing systems and incorporating the erasing media and the writing compositions. The present invention further provides writing instruments produced using the writing compositions.

A writing or coloring pencil has three layers obtained by co-extrusion, including an unexpanded polymer-based lead, an unexpanded intermediate protective layer surrounding the lead and comprising an ethylene (C1-C4 alkyl) acrylate copolymer, alone or as a blend with a styrene polymer, and an expanded styrene polymer-based synthetic wood material surrounding the intermediate protective layer.

A writing or coloring pencil has three layers obtained by co-extrusion, including an unexpanded polymer-based lead, an unexpanded intermediate protective layer surrounding the lead and comprising an ethylene (C1-C4 alkyl) acrylate copolymer, alone or as a blend with a styrene polymer, and an expanded styrene polymer-based synthetic wood material surrounding the intermediate protective layer.

A wax-based coloring crayon for a porous surface and for a non-porous surface includes at least one wax, an ethoxylated fatty alcohol, stearin, a filler, at least one pigment, and optionally an additive.

A wax-based coloring crayon for a porous surface and for a non-porous surface includes at least one wax, an ethoxylated fatty alcohol, stearin, a filler, at least one pigment, and optionally an additive.

A hydrophobic coating and a method for applying such a coating to a surface of a metallic substrate. The method can include anodizing a nanoporous layer of anodic metal oxide on the surface; cathodizing yttrium oxide nanoparticles onto the surface; applying a hydrophobic ceramic coating composition to the surface by an application method selected from the group consisting of: flowing, dipping, and spraying; and heating the coated surface at a cure temperature from about 150 C. to about 300 C. for at least 2 hours.

A hydrophobic coating and a method for applying such a coating to a surface of a metallic substrate. The method can include anodizing a nanoporous layer of anodic metal oxide on the surface; cathodizing yttrium oxide nanoparticles onto the surface; applying a hydrophobic ceramic coating composition to the surface by an application method selected from the group consisting of: flowing, dipping, and spraying; and heating the coated surface at a cure temperature from about 150 C. to about 300 C. for at least 2 hours.

Writing compositions capable of undergoing a color development when brought into contact with a specific substrate including a color change-inducing compound are provided. Application of the writing compositions to surfaces other than the intended substrate will avoid color development and prevent staining of the unintended surfaces. The writing compositions include at least one particulate filler including a clay, at least one leuco dye, one or more waxes chosen from a group consisting of polyethylene wax, soy wax, paraffin wax, and beeswax, at least one thermoplastic binder material including a polyethylene, titanium dioxide, and optionally at least one additive.

Writing compositions capable of undergoing a color development when brought into contact with a specific substrate including a color change-inducing compound are provided. Application of the writing compositions to surfaces other than the intended substrate will avoid color development and prevent staining of the unintended surfaces. The writing compositions include at least one particulate filler including a clay, at least one leuco dye, one or more waxes chosen from a group consisting of polyethylene wax, soy wax, paraffin wax, and beeswax, at least one thermoplastic binder material including a polyethylene, titanium dioxide, and optionally at least one additive.