Abstract

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.

IPC Classes  ?

• B43K 19/16 - Making non-propelling pencils
• B43K 19/02 - Pencils with graphiteColoured pencils
• B43K 19/14 - Sheathings
• C09D 13/00 - Pencil-leadsCrayon compositionsChalk compositions

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 colorless 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.

IPC Classes  ?

• C09D 13/00 - Pencil-leadsCrayon compositionsChalk compositions
• B43K 19/02 - Pencils with graphiteColoured pencils
• B43K 19/18 - Making pencil writing-cores

Abstract

The invention relates to a writing or coloring pencil comprising the following 3 layers obtained in a coextrusion process: - a polymer-based unexpanded lead; - an unexpanded protective intermediate layer that surrounds the lead and contains an ethylene (C1-C4 alkyl) acrylate copolymer alone or mixed with a styrene polymer; and - a synthetic expanded wood material that is based on a styrene polymer and surrounds the protective intermediate layer.

IPC Classes  ?

• B43K 19/00 - Non-propelling pencilsStylesCrayonsChalks
• B43K 19/16 - Making non-propelling pencils
• B43K 19/02 - Pencils with graphiteColoured pencils

Abstract

The present invention concerns an extrudable, unexpanded color pencil lead, comprising, by weight relative to the total weight of the lead: between 25 and 45%, and advantageously between 30 and 40%, of a polyolefin; between 25 and 50%, and advantageously between 30 and 40%, of a colorless mineral filler; between 4 and 20%, and advantageously between 5 and 15%, of a pigment coated with or mixed with a polyolefin wax; between 0 and 10%, and advantageously between 2 and 10%, of an additive, and between 10 and 30%, and advantageously between 15 and 25%, of stearate chosen from magnesium stearate, calcium stearate and the mixture of same. It further concerns the color pencil comprising a lead according to the invention.

IPC Classes  ?

• C09D 13/00 - Pencil-leadsCrayon compositionsChalk compositions
• B43K 19/02 - Pencils with graphiteColoured pencils
• B43K 19/18 - Making pencil writing-cores

Abstract

The present invention thus relates to a writing or color pencil comprising the following 3 layers obtained by coextrusion a polyolefin-based non-expanded lead, a non-expanded protective intermediate layer surrounding the lead and comprising a mixture of polystyrene and EVA, and an expanded synthetic wood material based on a styrene polymer surrounding the protective intermediate layer, the protective intermediate layer thickness/lead radius ratio being between 0.05 and 0.17, advantageously between 0.07 and 0.15.

IPC Classes  ?

• B43K 19/02 - Pencils with graphiteColoured pencils
• C09D 13/00 - Pencil-leadsCrayon compositionsChalk compositions
• B43K 19/16 - Making non-propelling pencils
• B43K 19/18 - Making pencil writing-cores

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.

IPC Classes  ?

• C09D 13/00 - Pencil-leadsCrayon compositionsChalk compositions
• B43K 19/02 - Pencils with graphiteColoured pencils
• B43K 19/18 - Making pencil writing-cores

Abstract

The present invention relates to a pencil for writing or colouring, which includes the following three layers produced by co-extrusion: a non-expanded polyolefin lead; with a non-expanded protective intermediate layer surrounding the lead and including a mixture of polystyrene and EVA; and an expanded synthetic wood material made of a styrene polymer surrounding the protective intermediate layer, the thickness ratio of the protective intermediate layer to the radius of the lead being from 0.05 to 0.17, preferably from 0.07 to 0.15.

IPC Classes  ?

• B43K 19/02 - Pencils with graphiteColoured pencils
• B43K 19/16 - Making non-propelling pencils
• B43K 19/18 - Making pencil writing-cores

Abstract

The present invention concerns an extrudable, unexpanded colour pencil lead, comprising, by weight relative to the total weight of the lead: - between 25 and 45%, and advantageously between 30 and 40%, of a polyolefin; - between 25 and 50%, and advantageously between 30 and 40%, of a colourless mineral filler; - between 4 and 20%, and advantageously between 5 and 15%, of a pigment coated with or mixed with a polyolefin wax; - between 0 and 10%, and advantageously between 2 and 10%, of an additive, and - between 10 and 30%, and advantageously between 15 and 25%, of stearate chosen from magnesium stearate, calcium stearate and the mixture of same. It further concerns the colour pencil comprising a lead according to the invention.

IPC Classes  ?

• C09D 13/00 - Pencil-leadsCrayon compositionsChalk compositions
• B43K 19/02 - Pencils with graphiteColoured pencils
• B43K 19/18 - Making pencil writing-cores