Initially erasable but subsequently permanent ball point ink
CA 1211579 A · Owner: Scripto, Inc. · Inventors: Muller, Frank A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for making and the composition for an initially erasable ink for a ball point writing instrument which ink is characterized by its initial erasability by ordinary pencil erasers when applied by a ball point writing instrument to an absorbent paper-like writing surface and which thereafter develops permanence. The method includes the steps of: (a) selecting elastomeric material from the group consisting of natural rubbers synthethic rubbers and mixtures thereof; (b) masticating the selected elastomeric material by subjecting same to high shear stresses; (c) coloring said masticated elastomeric material by forced impregnation of colored pigments into said elastomeric material while …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted September 16, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 16, 2003.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.