The present invention relates to a drafting material comprising a transparent base material which on one or both surfaces is provided with a hydrophilic coating containing polyvinyl alcohol and conventional additives.
Published European patent application No. 0,125,113 discloses hydrophobic layer supports having layers that enable them to absorb inks. The coatings employed for this purpose comprise mixtures of polyvinyl pyrrolidone and a compatible component, for example, polyvinyl alcohol.
Published German Application No. 33 30 420 discloses a recording material which comprises a coated substrate where the coating includes particles of a filler in a hydrophilic binder, such as polyvinyl alcohol.
Coated, transparent supports suitable for ink jet imaging processes are also known from U.S. Pat. No. 4,575,465. The coatings employed in accordance with this publication comprise mixtures of polyvinyl alcohol and vinylpyridine/vinylbenzyl copolymers in the form of their quaternary salts.
Finally, a process for the preparation of corresponding drafting materials is described in Published Japanese Application No. 59/222,381, where the transparent base is coated with a double layer containing polyvinyl alcohol.
It is also known to use mixtures of polyester and polyvinyl alcohol as overcoats for ink jet materials; see Japanese Published Application No. 60/046,289.
The known materials are suitable for aqueous inks employed to produce ink jet prints. However, it has been found that they are not suited for aqueous inks of the types employed for felt-tip pens of the type used in imaging or plotting apparatuses.
The knonw materials either do not accept the ink or the ink does not sufficiently adhere to the surface of the material, i.e., it is not wipe-resistant. In many instances, the layers are highly water-soluble, so that finger prints which can no longer be removed are left on the material during handling.