JPH0643570B2 - Crayons for drawing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drawing material used for drafting or drawing of a picture, that is, a crayon for drawing.

(Prior Art) Conventionally, crayon for elementary images such as Conte (brand name) can be smoothly written on paper with relatively large irregularities such as drawing paper, and can produce light and shade due to changes in writing pressure or friction after drawing. It has been used heavily. This crayon for drawing is traditionally crushed from charcoal, especially willow wood, paulownia wood and other charcoal powder, and kneaded with clay and molded and dried, or heat treated at a relatively low temperature. Was manufactured by

(Problems to be Solved by the Present Invention) However, the conventional crayon for drawing has the following problems. That is, first, charcoal is used as a raw material, but currently charcoal production has never been seen, let alone stable charcoal such as willow tree and paulownia tree used for drawing crayons. It is in an extremely difficult situation. Therefore, it has become difficult to produce a crayon for drawing with stable quality. Secondly, in the case of the conventional crayon for drawing, charcoal is crushed and used as a raw material, but in many cases, the particle size of the charcoal powder is not stable, and further, it is dried after molding in the manufacturing process or at a relatively low temperature. That is, 400 to 500 ° C
Since only a moderate heat treatment was performed, it was difficult to stably obtain a crayon for drawing with a uniform and smooth brush stroke.

The inventors of the present invention have diligently studied to provide a crayon for drawing with uniform quality without using these problematic charcoal and the like, and moreover, as a result, use carbon black and graphite powder together as a coloring material. According to the present invention, it was found that a crayon for drawing which is smooth in brushing and excellent in expressive power in which light and shade can be easily expressed is stably obtained, and the present invention has been accomplished.

That is, an object of the present invention is to stably provide a crayon for drawing, which has a smooth brush stroke and is excellent in expressiveness such as easy expression of shading.

(Means for Solving the Problems) The crayon for sketching according to the present invention for achieving the above object has a composition containing clay, carbon black and graphite powder as main components, and carbon black accounts for the total amount of the components. And the content of the graphite powder is 40 to 55% by weight.

(Operation) The present invention will be described in detail below.

The crayon for sketching of the present invention is characterized by containing, in addition to clay, carbon black and graphite powder, which have not been conventionally used as colorants, in the range of 40 to 55% by weight based on the total amount of components. , As long as it has the smoothness of brush stroke, the adhesion to the paper surface, the expression of light and shade, the bending strength required by the crayon for drawing by this composition and the handwriting can express the light and shade effectively and visually, It may also include a crayon for drawing made by using a manufacturing method.

There are various types of carbon black such as furnace black, channel black, thermal black, lamp black, and acetylene black depending on the manufacturing method, and any kind of carbon black including the above various carbon black can be used for the crayon for drawing of the present invention. You may mix and use 2 or more types. However, furnace black, which is easy to mix with clay, has a large coloring effect per unit weight, gives smooth brushing, and is capable of stably supplying a high-purity product from an industrial viewpoint, is carbon for crayon drawing of the present invention. Particularly preferred as black.

In addition, parameters such as particle size, structure, and oil absorption amount closely related to the structure are generally used to specify the properties of carbon black.

The characteristics of carbon black specified by these parameters depend on the characteristics of the crayon for drawing, such as the blackness of the handwriting, brush stroke, and the appearance of shade, the type and amount of clay and other materials, and various manufacturing conditions. The average particle diameter is 10 to 100 mμ, and more preferably 1
5 to 30 mμ, oil absorption is 35 to 150 ml of DBP (dibutyl phthalate) per 100 g, more preferably 55 to
It is preferably 120 ml.

However, carbon black having an average particle diameter or an oil absorption which is not included in the above range can be used depending on the purpose. Further, since carbon black having a large oil absorption amount, that is, a large structure, tends to have a large coloring power per unit weight, it is advisable to adjust the oil absorption amount or the structure of the carbon black used according to the density of the handwriting to be obtained.

In addition, carbon black is secondarily treated to give a certain functional group, especially an acidic functional group, the kind and amount of binder,
It has also been found that, depending on the circumstances, it is extremely effective in producing a delicate blackness with a very effective brush stroke.

Graphite powder used in combination with carbon black effectively functions to promote the brush lubricity. The graphite powder to be added may be artificial or natural (scale-like or earth-like), but the one that is more crystallized, especially L _C, which is the thickness of the graphite crystal in the C-axis direction, is 200 Å or more, and more preferably 500
Å More than graphite, especially the use of natural graphite powder with high crystallinity and good lubricity improves the writing more effectively,
The average particle size is preferably 1 to 40 μm, more preferably 15 μm or less, and more preferably 8 to 75%, more preferably 10 μm.
It is most effective to add -50%.

Carbon black and graphite powder are 40 ~
It is important to contain it in the range of 55% by weight, and if it is out of this range, it is not possible to impart a brush-writing function having excellent lubricity. The preferred method for producing the crayon for drawing of the present invention is as described in detail below.

The conventional crayon for drawing was either dried at about 100 ° C or heat-treated at a relatively low temperature of about 400 ° C before the structural water of the clay used as a binder was released to produce the product. In the case of crayon for drawing an invention, clay used as a binder forms a stable phase 700-
It has been found that when baking in a reducing atmosphere at a temperature of 1250 ° C., and more preferably 800 to 1100 ° C., a crayon for drawing with excellent quality can be obtained. In this case, kaolin, montmorillonite, and sericite are used as the clay. In some cases, more effects can be obtained by mixing one or more than two types.

It is not clear why the crayon for sketching according to the present invention is so excellent in brush writing that it is effective in expressing blackness and is suitable for rendering shades, but the extremely small structure of carbon black makes clay particles effective. Surrounding it as a unit structure, graphite particles that are larger than carbon black and clay particles are scattered in the chain, which creates a smooth brush stroke and effectively makes the structure of carbon black and clay effective. It is considered that the structure of the carbon black surrounding the clay particles is destroyed by adhering it to the irregularities and applying a writing pressure or pressure contact to develop an appropriate shade.

The crayon for drawing of the present invention is, for example, dehydrated by introducing various raw materials into a ball mill or the like by a method mainly performed conventionally.
Molding, drying, or kneading with a high-speed kneader or the like may be followed by the same steps, but of course the invention is not limited thereto. Further, in order to make the dispersion more uniform during kneading, an appropriate dispersant may be added, and the shape may be any of circular cross section, square shape, hexagonal shape, etc., or continuous molding or molding. Any of these methods can be used, and the method is not limited to the described method.

The crayon for sketching of the present invention may be put into a shape such as a wooden shaft or a paper roll for practical use, or may be held in a holder or the like for use. In addition, depending on the case, the writing may be carried out alone, and it can be applied to various writing instruments.

As the crayon for drawing, a harder one, an intermediate one, a softer one, etc. may be required, but when the carbon black, clay, or graphite powder of the present invention is added, the graphite powder or the like is blended. It can be adjusted by changing the ratio.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Furnace black MA-100 manufactured by Mitsubishi Kasei Co., Ltd., which has been given an acidic functional group by a special treatment as a coloring material, and purified natural graphite D-5 manufactured by Chuetsu Graphite Industry Co., Ltd. as a lubricant.
Kyoritsu Ceramic Raw Materials Co., Ltd. refined Kaori-based clay, Toyoku clay as a binder clay, and Daicel Chemical Co., Ltd.'s CMC1150 as a sizing agent are added to the respective strong kneaders according to the following formulation examples, and water is appropriately added and mixed, After preliminarily molding the obtained kneaded product, it was molded into a rod-shaped body having a circular cross section, dried, and fired at 1000 ° C. in a reducing atmosphere. We obtained a series of drawing crayons consisting of four types: hard, medium, soft, and extra soft.

(Effect) The crayon for sketching according to the present invention is extremely lubricious in brush stroke, and the desired expression of light and shade can be drawn well. When used for drawing or sketching, the crayon for drawing is new. It is possible to create a shade of black and white, and it is possible to obtain a crayon for drawing that is industrially stable, uniform, and has a large bending strength, and provides great value.

Claims (1)

[Claims] 1. A drawing having a composition containing clay, carbon black and graphite powder as main components, and the content ratio of carbon black and graphite powder in the total amount of components is 40 to 55% by weight. crayon.