JP3820773B2 - Colored pencil lead - Google Patents

Description

【００２４】
【発明の効果】
上表のように、本発明によれば、乾式製法で得られる色鉛筆芯であっても、モンタンワックスとパラフィンワックスを併用したので、強度、濃度、筆記時のカス出や筆記線の掠れ具合などが格段に改良された色鉛筆芯を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a colored pencil lead obtained by a so-called dry process using at least a thermoplastic resin as a binder, and using other extender, wax, lubricant, and coloring material, without drying or baking. is there.
[0002]
[Prior art]
The conventional colored pencil lead uses a combination of one or more organic binders, build materials such as talc and calcium carbonate, waxes such as carnauba wax and paraffin wax, metal salts such as calcium stearate, various inorganic types Mixing colorants such as organic pigments, dispersing and kneading using plasticizers and organic solvents as necessary, forming into a core with an extrusion molding machine, etc., and drying as necessary Has been obtained.
[0003]
Today, these color pencil lead manufacturing methods use a thermoplastic resin soluble in water, plasticizers and organic solvents as a binder, and mix build materials, waxes, lubricants, coloring materials, etc. under a solvent with a stirrer. In addition, kneading with three rolls while adjusting the amount of solvent to evaporate, uniformly dispersing, then forming into the desired core diameter with an extruder in the presence of these solvents, and drying the solvent The mainstream is a wet process that completely removes the material.
[0004]
There are two types of wet processes, one using water as a solvent and the other using an organic solvent such as ketone. The manufacturing method using water as the solvent uses water that does not easily volatilize at room temperature, and after molding to the core, in order to completely remove the moisture, the wax component in the composition is at a low temperature that does not dissolve for several tens of hours It is essential to perform the drying process. In addition, the production method using an organic solvent such as ketone uses an organic solvent that easily evaporates at room temperature. .
[0005]
[Problems to be solved by the invention]
In contrast to the wet manufacturing method, there is a dry manufacturing method in which a thermoplastic resin is heated and melted and kneaded and then extruded. In this manufacturing method, it is not necessary to remove the solvent and the plasticizer after molding, so that a finished product is obtained after molding. The process that does not require drying or heat treatment is shortened, and it is a preferable production method from the viewpoint of environment and hygiene, but the extender material and coloring material are generally dispersed by melting of the thermoplastic resin, so it generally tends to have a high viscosity. Compared to a colored pencil lead that is non-uniformly dispersed and obtained by a wet process, the quality tends to be low.
[0006]
In these conventional dry processes, it is known to use auxiliary waxes for the purpose of promoting the melting of the thermoplastic resin. Certainly, by using waxes, the melting temperature of the resin is apparently lowered, and the material viscosity is lowered to make the dispersion of the material uniform. Although a colored pencil lead having the property can be obtained, the overall quality is still insufficient, such as occurrence of residue during writing or the writing line being blurred.
[0007]
[Means for Solving the Problems]
Therefore, the present invention is a colored pencil lead based on a conventional dry manufacturing method, and even if a thermoplastic resin is used as a binder and a wax for lowering the melting temperature of the thermoplastic resin is used, the strength and color developability. It is intended to provide a colored pencil lead that is high and suppresses the occurrence of dregling during writing and curling of the writing line, and improves the above-mentioned problems by using two specific types of wax together Has been reached.
[0008]
That is, the present invention provides at least a thermoplastic resin as a binder, an extender, a wax, a lubricant, and a colorant, and in a colored pencil core obtained by a dry process , montan wax and paraffin wax as the wax. And a color pencil lead in combination with a weight ratio of 181: 19 to 149: 51 .
[0009]
Details will be described below.
The thermoplastic resin used as the binder in the present invention is basically any resin that can be extruded. For example, styrene resins such as acrylic styrene resin, acrylic styrene butadiene resin, polystyrene resin, polymethyl Acrylic resins such as methacrylate, polyethylene resins, polypropylene resins, and water-soluble resins such as polyethylene oxide resins and hydroxypropyl alcohols can be arbitrarily used. These resins can be used alone or in combination. However, in selecting a thermoplastic resin, it is also possible to select a material that is not thermally deteriorated as a material other than the resin, and the resin used melts at a temperature range lower than 180 ° C. It is preferable to use such a resin.
[0010]
Next, the Montan wax used in the present invention belongs to the classification of a natural wax, a mineral wax, and the raw material lignite is extracted with an organic solvent to remove the resinous material, and further with an acid such as nitric acid or chromic acid. Examples of grades that can be obtained by processing include S wax and LP wax. Next, these waxes are further esterified with higher alcohols or the like, or those partially saponified with alcohols and then saponified with metal oxides. The former representative grades include E, KPS, and DPE waxes, and the latter representative grades include O, OP, and OM waxes.
[0011]
The paraffin wax used in combination with the above-mentioned montan wax is obtained by distilling crude oil as a raw material under reduced pressure, taking out a light fraction, cooling and filtering to obtain a coarse wax, sweating or solvent deoiling, and washing with sulfuric acid in activated clay. A purified paraffin wax is obtained by treatment, and its structure is a general-purpose paraffin wax having a molecular weight of 300 to 500, which contains n-paraffin as a main component and contains some iso and cycloparaffin.
[0012]
As described above, the present invention is a combination of two kinds of waxes in a certain ratio, which has reduced the strength of the colored pencil lead in the conventional dry method, the wrinkling of writing lines at the time of writing, and the dripping out of the paraffin. The amount of the wax used is preferably 0.10 to 0.35 weight percent with respect to the amount of montan wax used 1. The reason for this is that if it is less than 0.10% by weight, the strength and wrinkle at the time of writing and the amount of residue appearing are eliminated, but the core may become hard and the color developability may decrease, while the weight of 0.35 This is because if the amount exceeds the ratio, the strength tends to be weak, and there is a tendency that a relatively large amount of wrinkles and scumming occurs during writing. The proportion of these waxes in the composition of the colored pencil lead also depends on the amount of thermoplastic resin used as the binder, but if used approximately 10%, the melting temperature of the thermoplastic resin is lowered. Enough.
[0013]
Conventionally known materials can be used except for the dry manufacturing method and using wax as described above. Various materials such as talc, calcium carbonate, mica, boron nitride, various lubricants such as stearic acid, calcium stearate, lithium stearate, zinc stearate, N-lauryl aspartic acid-β-lauryl ester, and organic and inorganic Various pigments of the system are treated with an appropriate disperser such as a Hensyl mixer. At that time, the material is granulated and then processed into a predetermined core diameter with an extruder. When granulating, in order to adjust the viscosity, water, an organic solvent or a plasticizer that will evaporate in the granulating temperature range is appropriately used according to the properties of the binder to be used. May be used.
[0014]
[Action]
In the present invention, compared with the conventional dry process, the reason why the strength and color developability are improved, and the occurrence of dregs and writing lines at the time of writing is improved is as follows. In other words, montan wax is a wax with good crystallinity and recrystallizes into a plate-like crystal shape that does not impair the orientation of the binder and extender during extrusion molding. Although there is an advantage that there is no blurring of the lines and writing lines, the crystallized montan wax apparently becomes a constitution, and there is a disadvantage that the coloring effect is lost because the hiding effect of the coloring material is lost, but the paraffin wax When used in combination, paraffin wax has poor compatibility with other materials, and can easily form an independent matrix in the core even after melting. It is presumed that the block-shaped colored material is peeled off from the core body by running into the core body, the apparent wear amount increases, and as a result, the color developability is improved.
[0015]
Hereinafter, the present invention will be described based on examples, but the present invention is not limited to the following examples. In the following, “parts” means parts by weight.
[0016]
【Example】
<Example 1>
Polystyrene resin (binding material) 280 parts Talc (extreme material) 1050 parts Calcium stearate (lubricant) 214 parts Red pigment (coloring material) 256 parts Montan wax (grade; E) 165 parts Paraffin wax 35 parts The material that was dispersed, kneaded and granulated in a Hensyl mixer was molded at 180 ° C. or lower using a screw extruder having a diameter of 30 mm to obtain a red colored pencil core having a core diameter of 2 mm.
[0017]
<Examples 2 to 5>
In Example 1, the amounts of montan wax and paraffin wax used were 181: 19 (weight ratio; 1: 0.11), 170: 30 (weight ratio; 1: 0.18), and 160: 40 (weight ratio; 1), respectively. : 0.25), 149: 51 (weight ratio; 1: 0.34), except that each was changed to obtain a red colored pencil lead having a core diameter of 2 millimeters.
[0018]
<Comparative Example 1>
In Example 1, a paraffin wax was not used, the amount of the paraffin wax used was added to the montan wax, and a red colored pencil lead with a core diameter of 2 mm was obtained in the same manner as in the example 1 except that the wax was all montan wax. It was.
[0019]
<Comparative example 2>
In Example 1, a red colored pencil lead having a core diameter of 2 millimeters was obtained in the same manner as in Example 1 except that montan wax was not used, the amount used was added to paraffin wax, and the wax was all paraffin wax.
[0020]
<Comparative Example 3>
Carboxymethyl cellulose 140 parts Talc 1360 parts Synthetic wood wax 200 parts Red pigment 300 parts Water 2000 parts The above blended composition is kneaded and dispersed with a kneader, and the moisture is adjusted while kneading with two rolls. The kneaded product was pelletized and molded with a screw extruder having a diameter of 30 mm, and then dried at 50 ° C. for 60 hours to remove moisture, thereby obtaining a red colored pencil lead having a diameter of 2 mm.
[0021]
<Comparative Examples 4-7>
In Example 1, the amounts of montan wax and paraffin wax used were (montan wax: paraffin wax =) 190: 10 (weight ratio: 1: 0.53), 182: 18 (weight ratio; 1: 0.09) 148: 52 (weight ratio; 1: 0.35) and 140: 60 (weight ratio; 1: 0.43), respectively, except that a red colored pencil lead with a core diameter of 2 mm was used. Obtained.
[0022]
As described above, the bending strength (unit MPa) of the color core obtained in each example and the concentration (unit D) as a substitute characteristic of color development were measured based on JIS S 6005, and the amount of occurrence of residue at the time of writing (unit: mg) ) Shows the weight generated when writing on approximately 5m on high-quality paper under the conditions of a load 300g, a writing angle of 75 ° and a pitch of 0.5 on a record type drawing machine used in the density measurement test. The state of occurrence is taken by magnifying an arbitrary part of the drawing paper 60 times with a video microscope, applying a 1 mm square tracing paper on the photograph, From the ratio (S1 / S2) of the area (S1) to the area (S2) of the uncolored portion, the coverage (unit%) of the wear powder on the writing line was determined from the average value obtained by measuring three arbitrary points. In addition, it means that there is so little twist that the value of a coverage is large. The measurement results are shown in Table 1.
[0023]
[Table 1]

[0024]
【The invention's effect】
As shown in the above table, according to the present invention, even in the case of a colored pencil lead obtained by a dry process, since montan wax and paraffin wax are used in combination, strength, concentration, scumming during writing and the degree of wrinkling of the writing line, etc. it is possible to provide a color pencil leads which are remarkably improved.

Claims (1)

In a colored pencil lead comprising at least a thermoplastic resin as a binder, an extender, a wax, a lubricant, and a colorant, and obtained by a dry process , montan wax and paraffin wax are used as the wax. Color pencil lead used in combination at a weight ratio of 149: 51.