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.

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.

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.

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.

Abstract: A writing instrument having a body, a main reservoir containing ink and housed in said body, a writing head projecting from the front part of said body, and a capillary connector for transferring ink from the main reservoir to the writing head. The instrument has an auxiliary reservoir containing an ink carrier liquid, and an actuator for releasing said liquid from the auxiliary reservoir so that said liquid flows into the main reservoir and expels the ink towards the connector. The carrier liquid contains the ink solvent, in particular water in the case of a water-based ink, and preferably contains all or any of the components of the ink in the main reservoir, whereby the original writing properties of the residual ink carried by the carrier liquid are preserved.

Abstract: The writing implement of the invention comprises: a) a body including an internal reservoir of ink and having a writing tip projecting from its front end; b) a capillary connector serving to transfer ink between the reservoir and the writing tip; and c) tip support arranged at the front end of the body to support the tip and assemble it with the capillary connector. The implement includes a compact one-piece capillary unit obtained by sintering thermoplastic powder, and constituting simultaneously the capillary connector and all or part of the tip support. The capillary connector and all or part of the tip support are constituted by a compact one-piece capillary unit preferably obtained by sintering thermoplastic powder.

Abstract: The colored liquid composition of the invention for a highlighter comprises a coloring element and water, the water content by weight lies in the range 10% to 30%. In addition, it comprises at least 40% of a liquid component having surface tension greater than 40 mN/m. In a variant, the coloring element is a tracer solvent having a fluorescent appearance under basic pH, in particular hydroxypyrenetrisulfonic acid, the pH of the composition lying in the range 8 to 9, and the component having surface tension greater than 40 mN/m is triethanolamine. Under such circumstances, the composition contains an acid to neutralize the triethanolamine in part in order to obtain the basic pH, for example hydrochloric acid.

Abstract: The liquid ink writing instrument has a body containing, from its rear end towards its front end, a reservoir for the ink and a front chamber containing a capillary element for transferring ink coming from the reservoir to a writing head. The front chamber communicates with ambient air. The writing head is fed with ink by the capillary element, and projects from the front portion of the body. The reservoir is separated from the front chamber by a flexible wall having shape memory and provided with slots. The flexible wall acts as a valve suitable for opening when the ratio of the pressure inside the reservoir over the pressure inside the volume of the front chamber facing the valve exceeds a first value, and of reclosing instantly as soon as the ratio becomes less than or equal to a second value, the valve releasing the ink in the form of a jet directed towards the rear face of the capillary element. The first value of the ratio of the pressures is preferably about 1.

Abstract: The writing instrument comprises a body, a main reservoir containing ink and housed in said body, a writing head projecting from the front part of said body, and a capillary connector for transferring ink from the main reservoir to the writing head. It further comprises an auxiliary reservoir containing an ink carrier liquid, and actuator means for releasing said liquid from the auxiliary reservoir so that said liquid flows into the main reservoir and expels the ink towards the connector. The carrier liquid contains the ink solvent, in particular water in the case of a water-based ink, and preferably contains all or any of the components of the ink in the main reservoir, whereby the original writing properties of the residual ink carried by the carrier liquid are preserved.

Abstract: The nib is constituted by a segment of a coherent, elongate element of high porosity material, with at least a first end shaped to form a writing tip. The pores and/or capillaries of said material are blocked over a limited thickness e in particular in the range 0.01 mm to 1 mm, at the longitudinal outer periphery of the elongate element, with the exception of the first end forming a writing tip. In a first variant, blocking is obtained by a sealing agent and performed by continuously impregnating the elongate element with a sealing bath, and setting the agent. In a second variant, the nib is constituted by sintered microbeads and blocking is obtained by localized hot-melting of the microbeads.

Abstract: The invention concerns a writing implement (1) comprising ink (5) in a fibrous or non-fibrous reservoir, a retarding agent soluble or dispersible in the ink and a nib (7) for transferring ink (5) from the reservoir to the writing medium and a method for making such a nib (7). The invention is characterised in that a retarding agent is included in the writing nib (7) and is adapted to be carried by the ink (5) when it is transferred into said nib (7). The inventive method consists in impregnating an already machined writing nib with a solution containing a specific amount of a retarding agent, drying the impregnated writing nib, without stirring, by heating at a temperature less than 60° C.

Abstract: The method of continuously manufacturing pencils or crayons consists in coextruding a filled first thermoplastic material referred to as “lead” material, and around it both an intermediate “protective” layer of a thermoplastic material having no expanding agent and a second thermoplastic material containing an expanding agent and referred to as “wood” material, and in cooling said coextruded thermoplastic materials. According to the invention, the thermoplastic material constituting the protective layer is determined so that during cooling it remains deformable while the lead material shrinks. The pencil is constituted by superposing a core of a filled first thermoplastic material referred to as “lead” material, a protective layer of a non-expanded thermoplastic material, and a layer of an expanded second thermoplastic material referred to as “wood” material.