Process for production of black crayon

Abstract

The invention provides a process for producing black crayon by using carbon black as the black pigment and a benzylidenesorbitol-type gelling agent, which process is freed from under-gelation. A process for the production of crayon which comprises dissolving or dispersing carbon black and a resin component in an organic solvent, dissolving at least one gelling agent selected from the group consisting of dibenzylidenesorbitol, tribenzylidene- sorbitol, and derivatives of both in the obtained solution or dispersion under heating, pouring the thus obtained raw material solution into a mold, and then solidifying the solution by cooling, wherein the carbon black is one having a mean primary particle size of 20 to 100nm.

Description

technical field [0001] The present invention relates to a method for producing a black crayon. Specifically, the present invention relates to a method for producing a crayon without poor gelation when carbon black is used as a black pigment and a benzylidene sorbitol gelling agent is used to produce a crayon. method. Background technique [0002] At present, as a method for producing crayons, the following method is known: adding a resin component to an appropriate organic solvent, stirring to dissolve it, adding a colorant to dissolve or disperse it, forming a solution, and heating it to the crayon. Add a benzylidene sorbitol gelling agent such as dibenzylidene sorbitol to this solution, make it dissolve, pour it into, for example, in a cylindrical molded container, cool it, and make it solidify (see Patent Document 1). [0003] As another example, as a method for producing a crayon using carbon black as a coloring agent and using a benzylidene sorbitol-based gelling agen...

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Problems solved by technology

[0004] In particular, as mentioned above, when using carbon black as a black pigment and using the above-mentioned benzylidene sorbitol compound as a gelling agent to make a crayon, in the final gelling process, poor gelation often occurs, which cannot be achieved. steadily making crayons

That is, the resin component and carbon black are dissolved and dispersed in an organic solvent, and the benzylidene sorbitol-based gelling agent is dissolved therein under heating to prepare a raw material solution. When the above-mentioned raw material solution is continuously heated and poured into the molding container, and allowed to cool and solidify, the gelling agent does not function and poor gelation occurs

[0005] When the heating time for dissolving the gelling agent is short, it is difficult to dissolve the gelling agent uniformly in the organic solvent, and a homogeneous crayon cannot be obtained

On the other hand, when the heating time is long, the obtained raw material solution is poured into a molding container, and when it is cooled and solidified, poor gelation occurs, and the crayons obtained as described above do not have the required gel hardness and tend to break when writing. So difficult to write on, depending on the situation, sometimes it doesn't even gel, and you can't get a crayon

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