Paper pencil lead
AssigneeConte
InventorsFrédéric CLAPTIEN, Julien GOUEREC, Philippe LEFEBVRE
Life of this patent
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Abstract
The present invention concerns an extrudable, unexpanded paper pencil lead, comprising, by weight relative to the total weight of the lead, between 40 and 60%, and advantageously between 44 and 50%, of graphite; between 15 and 40%, and advantageously between 20 and 35%, of a polyolefin; between 5 and 15%, and advantageously between 6 and 10%, of a colourless mineral filler; between 5 and 20%, and advantageously between 5 and 15%, of carbon black coated with or mixed with a polyolefin wax or a polyolefin; between 0 and 16%, and advantageously between 5 and 15%, of an additive. It further concerns the paper pencil comprising a lead according to the invention.
Claims19
A non-expanded, extrudable paper pencil lead, comprising, on a weight basis relative to the total weight of the lead:
- between 40 and 60% of graphite;
- between 15 and 40% of a polyolefin;
- between 5 and 15% of a colorless mineral filler;
- between 5 and 20% of carbon black coated with or mixed with a polyolefin wax or a polyolefin;
- between 0 and 16% of an additive.
The paper pencil lead as claimed in claim 14, wherein the polyolefin wax is a polyethylene wax.
The paper pencil lead as claimed in claim 14, which does not comprise any plasticizer.
The paper pencil lead as claimed in claim 14, which is extruded.
Dependencies are inferred from the claim text.