The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 14, 1993
Filed:
Mar. 03, 1993
Jacques Bachelet, Cremarest, FR;
Philippe Chavatte, Wimereux, FR;
Guy Chochoy, Saint Leonard, FR;
Jose Duez, Boulogne sur Mer, FR;
Claude Fouble, Ostrohove, FR;
Didier Lange, Saint Leonard, FR;
Conte S.A., , FR;
Abstract
According to the invention, the writing or coloring pencil is obtained by tri-extrusion of three thermoplastic materials forming the lead material, the expanded wood material and an intermediate protective layer, containing no expanding agent, which is compatible with the lead material and the wood material and has a melting point which is equal to or higher than the melting points of the lead material and the wood material. The three co-extruded materials all contain in particular the same basic component, such as for example a polystyrene-methacrylate copolymer. The protective layer can be of a different color from the other two layers. The writing or coloring pencil with protective casing between the lead and the expanded wood, all three being in thermoplastic material, is, in particular a pencil with soft or extra-soft lead.