JPS6227480A - Production of color lead - Google Patents

Abstract

PURPOSE:To obtain a noncalcination color lead which is excellent in bending strength and less susceptible to slitting, by kneading a binder with a colorant having an average particle diameter in a particular range and an extending agent a part of which is comprised of a fibrous matter and then extrusion molding the kneaded product. CONSTITUTION:A binder (A) such as nitrocellulose or cellulose acetate is kneaded with a colorant (B) having an average particle diameter of 0.1-10mum (e.g., org. or inorg. pigment) and an extending agent (C), a part of which is comprised of a fibrous matter, e.g., magnesium oxysulfate or potassium titanate. The kneaded product is extrusion-molded to obtain an intended noncalcination color lead. The color lead is suited for use as a color lead for mechanical pencils, pencils, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing a non-fired color lead used in mechanical pencils, pencils, etc. More specifically, it relates to the use of an m41-like material as at least a part of the two-body material.

(Prior Art) It is known to use a fibrous material as at least a part of a structural material in order to improve bending strength. For example, JP-A-52-88419 and JP-A-56-163171.
In the publication, a fibrous material of potassium titanate was published as
-18347 publication describes fibrous materials such as graphite and carbon,
There is a disclosure regarding each use.

(Problems to be Solved by the Invention) In the case of non-fired color cores, those obtained by using fibrous materials often tend to develop vertical cracks. In this case, the single-color core collapses in the direction of orientation of the fibrous material.

It is an object of the present invention to obtain a non-fired color core that has excellent bending strength and is less likely to cause vertical cracks.

(Means for solving the problem) Along with the use of fibrous materials, the average particle size of one colorant is 0.
Use one with a diameter of 1 to 1.0 μm. That is, the present invention has the following features:
The main ingredients are at least a binder, a coloring agent, and a conditioner, kneaded,
A method for producing a non-fired colored core formed by extrusion,
In the case where a fibrous material is used as at least a part of the body material, the coloring material has an average particle size of 0.1 to 1.
The gist is a method for manufacturing a color core characterized by using a 0 μm core.

The details will be explained below.

Binding materials include polyvinyl chloride, polyethylene, polystyrene, acrylonitrile/styrene J'4 resin,
Examples include nitrocellulose, cellulose acetate, phenolic resin, and polyvinyl alcohol. Among these, cellulose resins are preferred, and nitrocellulose is particularly preferred.

In addition to the above-mentioned fibrous substances, there are also silicon nitride, asbestos, and alumina.

Examples include magnesium oxysulfate.

Among these, potassium titanate and magnesium oxysulfate are preferred. Generally, the average particle diameter is 1 μm or less, and the average particle length is about 10 to 100 μm.

In addition, a physical material other than the fibrous material may be used in combination.

As the coloring material, both inorganic pigments and organic pigments can be used, but organic pigments are preferable because they have good color development properties.

The average particle size of this coloring material is 0.1 to 1.0 μm.

At 0.1 μm or less, the vertical crack is 08 μm.

One or more of the above materials, as well as lubricants and solvents used as necessary, are mixed uniformly, and after extrusion molding, the product is shaped into a predetermined size to obtain a product. Here, the amount of the colorant used is 10% of the total amount excluding the solvent.
It is preferable to keep it at about 20% by weight. In addition, drying treatment may be performed as necessary during the process.

(Example) Examples will be described below. Note that parts simply indicate parts by weight. Furthermore, the particle size was measured using a microscope.

[Example 1] Nitrocellulose 27 parts magnesium oxysulfate (average particle diameter approximately 0.5 μm, average particle length approximately 50 μm)
33 parts Watching Red NR3 (red pigment manufactured by Nippon Pigment Co., Ltd.: average particle diameter approximately 0.7 μm) 1
6 parts stearic acid 4 parts aluminum stearate 13 parts polyethylene wax 7 parts methyl ethyl ketone
150 parts The above materials were uniformly kneaded using three rolls, and after adjusting the solvent content, they were extruded into a thin wire using one extrusion molding machine.

After thoroughly drying with air, cut to the specified size and cut into diameter 0.
．． A 5 mm red core was obtained.

[Example 2] Everything was the same as in Example 1 except that Watching Red NR8 in Example 1 was changed to Schmirer Fast Orange V (orange pigment manufactured by Inu Nippon Ink ■: average particle diameter of about 0°3 μm). did.

[Example 3] Everything was the same as in Example 1 except that Watching Red NR8 in Example 1 was changed to Schmirer Fast Yellow 5GS (yellow pigment manufactured by Dainippon Ink ■: average particle diameter of about 0.5 μm). did.

[Example 4] Example 1 except that magnesium oxysulfate was replaced with potassium titanate (average particle diameter of about 0.6 μm, average particle length of about 15 μm).

Everything was the same as in Example 7.

[Comparative Example 1] Everything was the same as in Example 1 except that Watching Red NR8 in Example 1 was changed to Sumirer Neosol Red 2BY (red pigment manufactured by Dainippon Ink ■: average particle diameter of approximately 0.08 μm). I did the same.

[Comparative Example 2] Watching Red NR8 in Example 1 was replaced with Ultramarine 19
00 (Blue pigment manufactured by Daiichi Kasei Ikki: average particle diameter approximately 2 μm)
) All procedures were carried out in the same manner as in Example 1, except that .

[Comparative Example 3] Everything was the same as in Example 4 except that Watching Red NR8 was changed to Neosol Red 2BY (described above).

[Comparative Example 4] In Example 4, Watching Red NR8 was replaced with Ultramarine 1.
Everything was the same as in Example 4 except that the temperature was changed to 900 (described above).

[Comparative Example 5] Everything was the same as in Example 1 except that magnesium oxysulfate was changed to talc (average particle size: about 3 μm).

(Effects of the Invention) Table 1 shows the test results for the bending strength and longitudinal cracking resistance of the specimens obtained on each side. Note 1: Bending strength is JIS 5
2. According to 6005. For vertical cracking resistance, store the product in the lead tank of a knock-type mechanical pencil, and
．． The number of occurrences of vertical cracks (measured 10 times) is shown when knocking is repeated so that the sample protrudes by 5 mm and a writing load of 400.7 is applied at a writing angle of 6o0.

Table-1 As can be seen from Table 1, according to the present invention.

It is possible to obtain a product in which the reinforcing effect of the fibrous material is fully exhibited, and therefore the product has excellent bending strength, and the occurrence of vertical cracking when the fibrous material is used is sufficiently suppressed.

Claims (1)

[Claims] The main ingredients are at least a binder, a coloring agent, and an extender, kneaded,
A method for producing a non-fired color core formed by extrusion,
In the case where a fibrous material is used as at least a part of the body material, the coloring material has an average particle size of 0.1 to 1.
．． A method for manufacturing a color core, characterized in that a core of 0 μm is used.