JPH1036748A - Core for color pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a core for color pencils improved in strength, color- developing properties and feeling in writing. SOLUTION: This core for color pencils is a nonbaked type core in which at least a binder, a fibrous reinforcing material used at least as a part of the binder, a body material using N-lauroyl-L-lysine, a lubricating material, a wax using distearyl ketone at least as a part of the wax and a coloring material are used. In this case, 27-37wt.% of the fibrous reinforcing material, 5-15wt.% of N-lauroyl-L-lysine and 2-5wt.% of distearyl ketone each based on the total except the volatile solvent component are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a bending strength
Excellent in color development and writing, especially for shears with a diameter of 1 mm or less
The present invention relates to a non-firing type color pencil lead suitable as a lead pencil lead.

[0002]

2. Description of the Related Art Conventionally, a non-fired type color pencil lead is prepared by mixing, kneading, molding, mixing a binder, a coloring material, a body material, a lubricant, a wax, and other plastic materials used as necessary. It is manufactured by subjecting it to drying or the like. By the way, the characteristics required of a color pencil lead are strength, color development (density), and writing quality, and various approaches have conventionally been made to these required characteristics as described below. JP-B-62-3189 (adding a fibrous substance of potassium titanate), JP-B-5-19588 (adding a fibrous substance of basic magnesium sulfate) and JP-B-62-25195 (adding a gypsum whisker) Discloses that the strength can be improved by adding a fibrous material. In Japanese Patent Publication No. 19589/1993 (invention based on the present application), the strength and writing quality are improved by using a fibrous material as at least a part of the constitutional material and distearyl ketone as at least a part of the lubricant. It is disclosed that it is possible. In JP-A-8-120208 (invention based on the present application), by using N-lauroyl-L-lysine as a constitutional material, strength, color developability, and writing taste can be improved.
It is also disclosed that a colored pencil lead excellent in eraser erasability can be obtained.

[0003]

In the above, there is a problem in color development and writing taste.
Although the strength and writing taste are improved, and the coloring is also slightly improved,
In particular, further improvement in color developability is desired, and in the above, the strength, color developability, and writing taste, all of the required properties of the color pencil lead, can be improved,
Improvements in strength, color development, and writing quality are eternal issues required for colored pencil leads, and further improvement in quality has been desired.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a colored pencil lead with further improved strength, color developability, and writing quality. Various experiments based on the belief that it is very difficult to further improve the strength, color developability, and writing quality by simply using a reinforcing material, N-lauroyl-L-lysine, and distearyl ketone. It has been found that the object can be achieved by blending a fibrous reinforcing material, N-lauroyl-L-lysine and distearyl ketone in specific amounts, and the present invention has been completed. With fibrous reinforcement and N-lauroyl-L
A constitution material using lysine, a lubricant, a wax using distearyl ketone as at least a part thereof, a wax, and a non-fired type color pencil lead using at least a coloring material, wherein the fibrous reinforcing material is 27 to 37% by weight based on the total amount excluding the volatile solvent, N-lauroyl-L-lysine 5 to 15% by weight based on the total amount excluding the volatile solvent, and distearyl ketone 2 to 2 based on the total amount excluding the volatile solvent. The gist is a colored pencil lead made by using 5% by weight.

As the binder used in the present invention, any of synthetic and natural resins can be used. For example, cellulose derivatives such as carboxymethyl cellulose, nitrocellulose, cellulose acetate and cellulose nitrate, polymethyl methacrylate, polyvinyl alcohol, polyvinyl butyral, polyethylene, epoxy resin, polychlorinated cellulose Examples include vinyl, vinyl chloride-vinyl acetate copolymer, polystyrene, acrylic-styrene copolymer, acrylic-styrene-butadiene copolymer, tragacanth gum, gum arabic, guar gum and the like. The amount used is 20 to 30% by weight based on the total amount excluding the volatile solvent. If the amount of the binder is less than 20% by weight, the ratio of the binder to the total amount is reduced, though depending on the type of the binder used, and the practical strength as a colored pencil core, particularly a colored pencil core for a small diameter sharp pencil, is reduced. If the content exceeds 30% by weight, the strength can be obtained but the writing line may be thin.

As a constitutional material, a fibrous reinforcing material and N-lauroyl-L-lysine are used. A conventionally known fibrous reinforcing material can be used. For example,
Examples include fibrous materials of potassium titanate, fibrous materials of basic magnesium sulfate, fibrous materials of titanium dioxide, fibrous materials of silicon carbide, fibrous materials of silicon nitride, and fibrous materials of aluminum borate. The amount used is 27 to 37% by weight based on the total amount excluding the volatile solvent. The reason is that when the amount is less than 27% by weight, the effect as a reinforcing material cannot be exerted, and the strength becomes insufficient. When the amount exceeds 37% by weight, the strength can be obtained, but the fibrous form can be obtained. This is because the fiber of the reinforcing material is more likely to be caught on the convex portion of the paper on the paper surface, and writing taste and coloring are deteriorated.

N-lauroyl-L-lysine is obtained from natural amino acids L-lysine and lauric acid, has an average particle size of 10 to 20 μm (electron microscopy), and has a decomposition temperature of 230 μm.
At ℃, it is almost insoluble in organic solvents other than strong acids and strong alkalis, has no hygroscopicity, and is a stable white powder. In addition, N-lauroyl-L-lysine is a plate-like crystal and has a cleavage property (each layer is sheared). Is a soft organic substance that has a significantly lower coefficient of friction than talc and mica, and has very high lubricity and is a conventionally known inorganic substance such as talc, mica or calcium carbonate. And is used in an amount of 5 to 15% by weight based on the total amount excluding the volatile solvent. The reason is that when the amount used is less than 5% by weight, the strength is improved because the shaping effect of the binder used in the colored pencil lead having a small diameter of 1 mm or less is not hindered, The effect of promoting abrasion with lubricants and waxes is reduced, and the coloring property and writing taste are deteriorated. When the content exceeds 15% by weight, the effect of promoting abrasion with lubricants and waxes is enhanced, and the coloring property is improved. This is because the shaping effect is improved, but the shaping effect of the binder is weakened and the strength is reduced. As a constitutional material, it is better to use only the fibrous reinforcing material and N-lauroyl-L-lysine to obtain a color pencil core having the bending strength of the color core, and excellent in writing taste and coloring. Although it can be used, it is possible to use N-lauroyl-L-lysine in combination with a conventionally known constitutional material such as talc, mica, and calcium carbonate, in particular, so as not to impair the lubricity of N-lauroyl-L-lysine.

[0008] The lubricant is added to improve the slip during writing, and specific examples thereof include stearic acid, metal salts of stearic acid, various aspartic esters, and the like.

As the wax, a ketone-based wax which is solid at room temperature, called distearyl ketone, is used, and is a plate-like crystal having a particle diameter smaller than that of N-lauroyl-L-lysine. Even after melting, it solidifies by cooling in a lump, but has the property of peeling off with a small shear force. This distearyl ketone is N-lauroyl-L-
Scattered on the surface or inside the composite of lysine and fibrous reinforcement,
During writing, continuous cracks due to cleavage of N-lauroyl-L-lysine are received by the adhesive force as wax, and the bending strength of the colored pencil core is maintained. In addition, distearyl ketone is weaker than N-lauroyl-L-lysine, but has a self-cleaving property, so that it promotes abrasion between N-lauroyl-L-lysine and the fibrous reinforcing material. effective. The amount used is 2 to 5 with respect to the total amount excluding the volatile solvent.
% By weight. The reason is that when the amount used is less than 2% by weight, the chain of the binder covered on the surface of N-lauroyl-L-lysine cannot be cut off, resulting in a colored pencil core with low coloring property and 5% by weight. Is exceeded, the color developability is improved, but this is because distearyl ketone is N-lauroyl-L
-The lysine does not act as a wedge, but rather wears the entire composite of N-lauroyl-L-lysine and the fibrous reinforcement, thereby increasing the location at which the chain of the binder is cut, resulting in a color core This is because the bending strength of the steel sheet decreases. still,
Distearyl ketone has good compatibility with solvents, and in order to exhibit a further effect, for example, dry or wet distearyl ketone is previously applied to the surface of N-lauroyl-L-lysine or fibrous reinforcing material. Can be used.

As the coloring material, various inorganic and organic pigments can be used without distinction.

[0011] The colored pencil lead of the present invention, in addition to the above materials,
Various plasticizers such as diallyl phthalate, tricresyl phosphate, and polycarbonate are appropriately blended, and an organic solvent such as methyl ethyl ketone and methyl acetate is added, kneaded and molded.
What is necessary is just to dry and manufacture as needed.

[0012]

Although it is not clear why the strength, color developability and writing quality can be relatively improved, it is not possible to use a specific amount of fibrous reinforcing material, N-lauroyl-L-lysine and distearyl ketone. It seems that these act synergistically and improve for the following reasons. That is, regarding the strength improvement, the orientation effect of the fibrous reinforcing material contributes, and the improvement of the coloring property and the writing taste is achieved by combining the composite fibrous reinforcing agent covered with the binder with N-lauroyl-L-lysine. It is considered that the role of distearyl ketone as a wedge material for improving the degree of freedom is considered to be great. Probably, distearyl ketone does not reduce the bonding strength of the resin and helps the cleavage of N-lauroyl-L-lysine. This is probably because the fibrous reinforcing material gives a lubricating effect to the paper surface.

[0013]

【Example】

<Example 1> Nitrocellulose 24 parts by weight Basic magnesium sulfate fibrous substance 32 parts by weight N-lauroyl-L-lysine 10 parts by weight (Ajinomoto Co., Inc. Famex L12) Stearic acid 9 parts by weight Distearyl ketone 4 Parts by weight Phthalocyanine bleed 17 parts by weight Propylene carbonate 4 parts by weight Methyl ethyl ketone 100 parts by weight After kneading the above materials while adjusting the solvent material with three rolls,
It was extruded into a fine wire and dried in a dryer at 80 ° C. for about 8 hours to remove the solvent, thereby obtaining a blue core for a sharp pencil having a nominal diameter of 0.5.

<Examples 2 to 4> In Example 1, the amount of the fibrous material of basic magnesium sulfate was changed to 26, 35, 3
A blue core was obtained in the same manner as in Example 1 except that the weight was changed to 9 parts by weight.

<Examples 5 to 7> A blue core was obtained in the same manner as in Example 1 except that the amount of N-lauroyl-L-lysine was changed to 5, 13, and 15 parts by weight.

Examples 8 to 10 A blue core was obtained in the same manner as in Example 1, except that the amount of distearyl ketone was changed to 2, 3, and 5 parts by weight.

<Example 11> In Example 1, distearyl ketone was placed in a beaker of 40 parts by weight of methyl ethyl ketone, and heated to about 50 ° C to dissolve the distearyl ketone. A blue wick was obtained in the same manner as in Example 1 except that the ethyl acetate was vaporized to give a fibrous form of basic magnesium sulfate coated with distearyl ketone.

Comparative Examples 1 and 2 A blue core was obtained in the same manner as in Example 1 except that the amount of the fibrous material of basic magnesium sulfate was changed to 25 and 40 parts by weight.

Comparative Examples 3 and 4 A blue core was obtained in the same manner as in Example 1 except that the amount of N-lauroyl-L-lysine used was changed to 4, 16 parts by weight.

<Comparative Examples 5 and 6> A blue core was obtained in the same manner as in Example 1 except that the amount of distearyl ketone was changed to 1, 6 parts by weight.

The results obtained by measuring the bending strength (strength), density (color tone) and dynamic friction coefficient (writing taste) of the samples obtained in Examples 1 to 11 and Comparative Examples 1 to 6 are shown in Table 1. 2
Shown in The bending strength of the core is measured according to the measuring method of JIS S6005 (unit is MPa), the density of the writing line is the same as the density measurement of writing line according to JIS S6005 (unit is D), and the dynamic friction coefficient is Using a kinetic friction tester, a holder containing a colored pencil lead in a copper disc shape is set vertically, and the resistance of the colored pencil lead to the copper plate when the disc is rotated with a load of 400 g is quantified. The lower the value, the better the writing taste.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

As described above, the present invention can provide a color pencil lead excellent in writing taste and color developability of the conventional color lead while having bending strength.

Claims (1)

[Claims] 1. A binder, a constitutional material using fibrous reinforcing material and N-lauroyl-L-lysine as at least a part thereof, a lubricant, and a wax using distearyl ketone as at least a part thereof. A non-fired type color pencil lead using at least a coloring material, wherein the fibrous reinforcing material is 27 to 37% by weight based on the total amount excluding the volatile solvent.
A colored pencil lead comprising 5 to 15% by weight of N-lauroyl-L-lysine based on the total amount excluding the volatile solvent, and 2 to 5% by weight of distearyl ketone based on the total amount excluding the volatile solvent.