JPS59157161A - Lead for colored pencil - Google Patents

Abstract

PURPOSE:To obtain a lead for colored pencil which exhibits sufficiently dense color for naked eye and cannot be copied e.g. by diazo copying machine, by using a resin as a binder, a wax as a lubricant, a light-transmitting inorganic fine powder as an extender pigment, and a specific amount of a red dye as a colorant. CONSTITUTION:The objective lead for colored pencil can be obtained e.g. by kneading (A) 5-40wt% of a resin (e.g. nitrocellulose) with (B) 0.15-5wt% of a red dye, and kneading the obtained mixture with (C) 5-40wt% of a wax (e.g. paraffin and stearic acid, etc.) and (D) 10-60wt% of a light-transmitting inorganic fine powder (e.g. talc).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a colored pencil lead, and more particularly, the present invention relates to a colored pencil lead that exhibits sufficient coloration when visually observed. This invention relates to a colored pencil lead that does not leave marks on the object when it is copied using the diazo method.

Pigments are usually used as the coloring material for two-color pencil leads. Of course, dyes can also be used, but pigments have a higher ability to hide traces and produce more colorful colors.

By the way, in a type of copying such as diazo copying in which photosensitive paper is reacted using transmitted light, it is often desired to erase some drawn lines on the original paper before copying.

For example, this is the case when you do not want to copy a sentence or a check mark on a diagram.

In such cases, the colored pencil leads using pigments as described above are not preferred because their high hiding power is a hindrance.

This is because it is difficult for handwriting to pass through the wavelengths of the photosensitive paper's reactive region.In other words, in this case, it is better to use dye as the colorant.

However, colored pencil leads using dyes cannot completely transmit the wavelengths in the reaction region of the photosensitive paper due to the presence of the dye itself or other materials, so they transmit as much of the wavelengths in the reaction region as possible. That is, materials including dyes with high transmittance must be selected. Of course, when visually inspected, the handwriting must be sufficiently colored.
In order to satisfy the above-mentioned demand for special uses, one more condition must be added. 1
This is because even if the material selection is the best, the transmittance of the trace itself cannot be determined. 1l19
As the proportion of the material increases, the coloration becomes more sufficient for visual observation, but the transmittance decreases. In addition, the softer the color (the softness of Oki brush lead corresponds to the softness and hardness of Kuroishi), the more similar the tendency becomes.

If you are using a soft colored pencil
There is also the question of whether it is better to use higher pressure when using colored pencils and lead. I'm sure (Te.

This question is natural, since the pressure of the pen can be determined by the will of the user, whether it is because their hands are hot or whether they are attached to a machine. but.

If you use high pressure, the colored pencil lead will easily break.

Also, if you lower the writing pressure, it looks good at first glance, but in order to do that, you have to use a soft colored pencil, and this soft colored pencil lead has a negative effect on low writing pressure.
This tends to cause shading in handwriting (including shading due to minute irregularities), and it tends to leave unclear lines on the photosensitive paper. Moreover, in the case of 2 handwriting, the user's writing pressure is 'colored pencil lead'.

It does not depend much on scales.

The present invention is the result of intensive research aimed at satisfying the numerous conditions mentioned above, and includes a resin as a binder, a wax as a lubricant, a light-transmitting inorganic fine powder as an extender, and
The main ingredient is at least a red dye as a coloring agent 6 in a proportion of 0.2 to 5 parts by weight based on the total amount, and a pencil lead.First, an example of production will be explained. Note that "parts" simply refer to parts by weight.

30 parts of nitrocellulose as a binder and 0.6 part of oil pink (an oil-based dye manufactured by Orient Chemical Handicraft Co., Ltd.) as a coloring agent are kneaded in portions using a low boiling point solvent. −
;4. , 10 parts of iTE lubricant, 10 parts of rough-in, and 20 parts of stearic acid.

Again, use a low boiling point solvent and knead thoroughly.

Ref 2 [! 1 part and 20 parts of 5-Ben (organic bentonite manufactured by Toyojun Yoko Co., Ltd.) are thoroughly kneaded, and when the solvent is released to a certain extent and the appropriate viscosity is reached, it is extruded into a cape line shape, the solvent is removed, and a temporary length is obtained. If you cut it squarely, you will get a colored pencil lead with a reddish 9# and a somewhat transparent feel. It is also possible to use a plasticizer or the like to improve molding stability.

Cocote and nitrocellulose were selected according to the dye. In other words, it is possible to use a water-based dye, but it is necessary to increase the suppression of crosstalk (when using a water-based dye, the resin used as the binder should also be water-soluble). As a result, tokufuyuishi is prone to problems in that its strength gradually decreases due to moisture absorption over time due to moisture in the air, and therefore oil-based dyes are preferred. ;.

In order to uniformly knead the oil-based dye, it is best to use an oil-soluble resin together with a solvent. Nitrocellulose is oil-soluble and can provide sufficient strength as a binder. Examples of resins that can be used other than nitrocellulose include styrene resins, acrylic resins, and ester resins. Well, the power differs depending on the material used.

The preferred usage ratio is 15 to 5 of the total amount remaining as colored pencil lead.
0 weight coefficient weight.

Paraffin and stearic acid were selected because it is desirable that they transmit as much light as possible, but as a wax that is a lubricant.

In addition to these, Toki Nderifwa 1゜ Lunata Te.
Can I use W/2X etc.? The preferred usage ratio is about 5 to 40% by weight, similar to the binder. 4 Kurji and S-13en are optically transparent. That is,.

Inorganic fine powder is generally used as the body material, but compared to resin as a binder or wax as a lubricant, it can be the biggest cause of inhibiting light transmission, so care must be taken in its selection. in general.

Those having at least 5102 as the main structural component tend to be good. Further, +5Ben is a type of organic bentonite, and as described above, the extender is about 1 part by weight of the organic material.

Now, let's talk about dyes. The dye used is red. This has a great relationship with the reaction area of the photosensitive paper.

Generally, the reaction area of photosensitive paper is 650 mμ to 420 mμ
The wavelength is on the shorter side. In order to transmit light with such short wavelengths, it would be preferable to use kidney-based dyes. This can be inferred from the fact that blue objects transmit blue light, that is, light with short wavelengths.

However, there is one blind spot here. The writing surface is whitish, like regular paper. If you draw red and blue lines on a white object.

Visually, red looks clearer. That is, red causes less visual fatigue even in a diluted state. Now, if we compare the renal dye and the red dye, which transmits only 70% of the light, to the reaction area of the photosensitive paper, we can see that the red dye is 2.
If the dye is diluted twice as much, the transmittance of red dye will be higher.

The above is the reason why a red dye was selected in the present invention. As for the red dye, one may be selected that gives the impression of red, pink, or purplish red as a colored pencil lead.

However, the proportion of red dye used must be carefully examined based on the above results. Since ingredients other than red dyes are related to strength and writing feel, they can be used in a fairly wide range of proportions, but red dyes cannot be diluted too much or used in large quantities.゜Ratio of red dye used (is 01 of the total amount forming the colored pencil lead)
5 to 5 parts by weight, more preferably 0.17 to 1.3 parts by weight. If the amount is less than 15% by weight, the color development will be insufficient even though it is a red dye, and if it is more than 5 parts by weight, the above-mentioned problem of shading becomes too thick when using low writing pressure.

The test results of the colored pencil lead obtained in the above production example are shown.

A load of 100, P, 200/, 300, and P was applied to the lead for a mechanical pencil with a diameter of 0.09 mm, and the lead was written vertically on thin white high-quality paper.
When copies were made using a diazo copying machine manufactured by Ricoh (product name: Rifpy Diazo 1 manufactured by Ricoh using photosensitive paper SDR) at several different copying speeds, no handwriting remained on the photosensitive paper. In addition, when we similarly tried to copy handwriting written twice in the same place under a load of 6001, we found that if the copying speed was fast, the handwriting remained on the photosensitive paper. However, in this case as well, draw lines with a commercially available water-based black ink and set the appropriate copying speed.

In other words, we investigated the existence of a speed range in which ink handwriting can be clearly reproduced without over-coloring the entire photosensitive paper.
No handwriting from the colored pencil lead was left despite the copying speed considered to be the most suitable.

Next, the amount of oil pink used in the above production example was reduced to 0.
Similar tests were conducted on products manufactured by changing 6 parts to 01 parts, 02 parts, 1 part, 3 parts, and 6 parts, and the results were mostly good, but the products made from 01 parts showed good results. Even when the load was increased to 4001, visual inspection was insufficient and the result was 9 cm. 6 copies (at a d load of 2001 or more, handwriting was left on the photosensitive paper, but at a copying speed that did not leave handwriting, the ink handwriting became unclear).

As described above, the colored pencil lead of the present invention greatly satisfies the need not only for ordinary chain writing but also for not leaving handwriting on the object to be copied.

Patent applicant: Bentel Co., Ltd.

Claims (1)

[Claims] Resin as a binder, wax as a lubricant, light-transmitting inorganic fine powder as a substance, and 0.15% of the total amount.
A colored pencil lead containing at least one of the main ingredients is a red dye as a coloring agent in a proportion of 5% by weight.