JPS63130379A - Copying material - Google Patents

Abstract

PURPOSE:To provide an inexpensive copying material having excellent color forming characteristics, by using a specified mixed hydrocarbon oil as a solvent of a solution containing dissolved therein an electron-donative color former capable of forming a color upon contact with an electron-acceptive color developer. CONSTITUTION:A copying material comprises a solution which contains dissolved therein an electron-acceptive color developer and an electron-donative color former capable of forming a color upon contact with the color developer. The solvent comprises a mixed hydrocarbon oil which comprises mainly components in a boiling point range of 160-260 deg.C (as reduced to a value at normal pressure), namely, naphthene hydrocarbons, isoparaffins and tetralin hydrocarbons, and contains 50-85wt% of the naphthene hydrocarbons, 2-15wt% of the tetralin hydrocarbons, 10-40wt% of the isoparaffins and, further, up to 5wt% of alkylbenzenes and alkylnaphthalenes and up to 10wt% of normal paraffins.

Description

[Detailed description of the invention] [Field of use in R business] The present invention relates to recording materials, in particular pressure-sensitive copying materials.

[Prior art 1] Conventionally, a colorless electron-donating coloring agent (hereinafter referred to as "coloring agent 1") is incorporated in the form of a solution in a microcapsule film and applied to one side of paper, and the same is applied to another side of the paper. An electron-accepting substance (hereinafter referred to as color developer 1) such as clay or polymeric material that has the property of reacting with a color former to develop color is applied, and when used, these surfaces are stacked facing each other. u1
2. Description of the Related Art Pressure-sensitive copying paper is known as a recording material that records copies by applying pressure.

The recorder of this scale is A81's copy/recorder (the corner is the brush L', and the microcapsule film is torn by pressure such as type pressure 111).
First, a color forming agent solution is poured out and brought into contact with a color developing agent applied to the surface of paper placed facing each other to form a color.

In addition, each coating has 11 layers that have a coloring mechanism like this.
There is also known a recording method in which a microcapsule layer as an inner layer and a color developer layer as an outer layer are laminated and coated on one side of a sheet of paper. The color development of this recording material 'RIM <yo, writing pressure,
The microcapsule film is split by type pressure, etc., and a color former solution is released, which is brought into contact with a color developer coated on the outer layer to develop color.

The color former solution used in these recording materials 11 is a solution in which one or more electron-donating color formers are dissolved in a hydrophobic solvent of 2FJ or more. The hydrophobic solvent used here must meet the following requirements.

In other words, it is non-toxic, has no unpleasant odor, the solvent itself is colorless or very light in color, non-volatile, has good solubility of the coloring agent, and has the ability to dissolve the coloring agent. It has stability of solution, becomes a stable microdispersion upon microencapsulation, can form a microcapsule film on the microdispersion, has storage stability of MIC [1 Kabupil], Capsules can be coated uniformly and to a desired thickness on the coating material, and the color forming agent prevents the color reaction that occurs when it comes into contact with the color developer.
``Also, the speed of coloring is fast, and when using paper coated with a polymeric material such as a color developer, the polymeric material must be dissolved to ensure close contact with the coloring agent, and the color image will not bleed. It is possible to obtain a clear colored image even after being stored in Ai!!II.

Chlorinated diphenyl, which has traditionally been widely used as a solvent for this type of recording material, is extremely toxic and accumulates in the human body, causing various problems. This poses a huge problem when the product is constantly handled by hand, such as with pressure-sensitive copying materials coated with microcapsules, and is no longer used. As an alternative to this, 1-
Phenyl-1-xylylethane, 1-)1nyl-1-(
diarylalkane such as ethyl)1nyl)ethane
; Aromatic IA hydrocarbon oils having two or three thea aromatic rings, such as hydrogenated ternoenyl, are used.

However, these solvents are expensive, and in order to manufacture pressure-sensitive copying paper at low cost, it is widely practiced to mix a cheaper auxiliary solvent with the above-mentioned solvent.

Also, some of the solvents mentioned above have high viscosity, but if high viscosity oil is used as it is, the particle size will decrease during encapsulation. lWJ is difficult, and in addition, the flow of the coloring agent solution released from the capsule during pressure printing! Coloring performance is poor due to poor vItit.

Even in such cases, the above-mentioned auxiliary solvent is used to adjust the viscosity, thereby making it easier to control the particle size during encapsulation and further improving the color development performance.

In addition, chlorinated paraffin compounds with less expensive solvents are also used in some areas. However, chlorinated paraffin oil has a high viscosity and is generally used in combination with a co-solvent of lower viscosity.

Examples of auxiliary agents include petroleum solvents such as kerosene, isoparaffinic solvents, normal paraffinic solvents, C1o~
C13 linear alkylbenpines and the like are widely used.

However, solvents containing these auxiliary solvents have various problems. In other words, paraffinic solvents such as kerosene, isoparaffin, and normal paraffin have poor solubility in color formers, so mixing them limits the concentration of color formers and further reduces the stability of the solution by causing recrystallization. . In addition, these auxiliary solvents have low dissolving power when a polymeric material such as phenolic resin is used as a color developer, so of course when used together with a low viscosity main solvent,
Even when used in combination with high viscosity oil, color development may not be improved, but rather may be decreased. Further, straight alkylbenzene also has drawbacks such as lowering the dye solubility and slowing down the speed of color development, and is also expensive.

Aromatic hydrocarbon oils such as low-boiling point alkylbenzenes or alkylnaphthalenes have excellent color former solubility and color forming properties, but have strong odor and are not suitable for use as auxiliary solvents.

[Problem to be Solved by the Invention 1] The purpose of the present invention is to solve the above-mentioned problems of the prior art, provide a copying material with excellent color development performance, and also achieve economical effects. The purpose is to do so. More specifically, it is an object of the present invention to solve the drawbacks of the main solvent and auxiliary solvent conventionally used as dye solvents for copying materials, such as pressure-sensitive copying paper, and to produce a copying material that has excellent coloring properties and is inexpensive. The purpose is to provide materials.

Means for Solving Problem E] The object of the present invention is to provide a copying material using a solution in which an electron-accepting color developer and an electron-donating color former that develops a color when in contact with the color developer are dissolved. in which the solvent of the solution is 160 to
Contains mainly components within the boiling point range of 260°C (normal pressure equivalent), substantially consists of naphthenic hydrocarbons, isoparaffins, and tetralin hydrocarbons, and has a naphthenic hydrocarbon content of 50 to 85% by weight %, tetralin hydrocarbon content 2 to 15% by weight, isoparaffin face content 10 to 40% by weight, further content of alkylbenzenes and alkylnaphthalenes of 5% or less by weight, normal paraffin content This is achieved by the copying material according to the invention, which is characterized in that it consists of a hydrocarbon mixture oil of not more than 10% by weight.

[For production] The present invention will be explained in more detail below.

The solvent used in the present invention needs to have a specific boiling point range and contain specific components. First, talking about the boiling point range, the solvent has a boiling point of 160 to 260 when converted to normal pressure.
It is necessary that the oil be a hydrocarbon mixture oil containing mainly components within the temperature range of .degree. When a component having a boiling point of less than 160° C. is used as a solvent, the coloring rate of the copying material is high, but the odor is large and it is not practical. Furthermore, because of its high vapor pressure, it is highly flammable and poses a safety problem. Further, a fraction exceeding 260° C. has a small odor and is preferable in terms of the working environment, but it reduces the rate of color development. The solvent is then a hydrocarbon mixture oil consisting essentially of naphthenic hydrocarbons and isoparaffins, and tetralin hydrocarbons. The content of naphthenic hydrocarbons in the solvent is 50
~85% by weight is required. If it is less than 50%, the solubility of the color former will be lowered when used as an auxiliary solvent, and furthermore, the color development rate of the copying material Y1 will be lowered when a phenolic resin is used as a color developer. If it exceeds 85%, the odor will worsen. Due to the presence of isoparaffin, the solvent of the present invention has excellent odor and viscosity reducing effects, but if it is less than 10%, such improving effects cannot be obtained.

If it exceeds 40%, the odor and viscosity reducing effects are excellent, but the solubility of the phenolic resin as a color former and color developer decreases, resulting in a decrease in color development rate.

The presence of the tetralin hydrocarbon provides excellent solubility in the phenol resin as a color forming agent and color developer, and is dedicated to improving the color development rate. Tetralin hydrocarbons herein include tetralin, alkyltetralins, indane, and alkylindanes. If it is less than 2%, the dissolving power is insufficient, and if it exceeds 15%, the solubility is excellent, but the odor becomes worse. It is desirable for the present invention that the amount of normal paraffins, alkylbenzenes, and alkylnaphthalenes is small.

That is, since normal paraffin easily crystallizes, it is necessary for the present invention to reduce the content to 10% or less.

Aromatic hydrocarbons such as alkylbenzenes and alkylnaphthalenes have excellent solubility in color formers and phenol resins as color developers, and are desirable components from the perspective of improving color development properties, but they are desirable from the viewpoint of odor and toxicity. From this point of view, it is preferable that the amount is less than t, and in the present invention, it is necessary that t be 5% or less. As mentioned above, the present invention solves the problems of odor and toxicity by reducing the content of aromatic hydrocarbons such as alkylbenpines and alkylnaphthalenes as much as possible, and also substantially reduces the content of aromatic hydrocarbons such as alkylbenpines and alkylnaphthalenes. By specifying the content, aromatic hydrocarbons such as alkylbenzenes or alkylnaphthalenes can be dissolved even if they are not substantially combined. It has a high strength and provides superior solubility and coloring properties compared to the paraffinic solvents mentioned above. Furthermore, compared to aromatic hydrocarbon oils with low boiling points, excellent properties such as significantly less odor can be obtained. Therefore, each component and its content have important significance.

Next, we will discuss the method for producing the solvent used in the present invention.

Although the solvent of the present invention can be obtained by mixing component compounds having specific boiling points, such a method is not necessarily economical. A preferred manufacturing method is as follows. In other words, mainly 160
It is obtained by subjecting a fraction consisting of fractions in the boiling point range of ~260°C to hydrorefining for desulfurization and/or denitrification and/or dehydrogenation of olefins, and then adsorbing and separating normal paraffins. Another method is to obtain a fraction consisting essentially of naphthenic hydrocarbons, tetralin hydrocarbons, and isoparaffins.

Boiling point obtained by distilling crude oil (normal pressure conversion i)
The 160-260° C. fraction corresponds to a so-called straight-run kerosene fraction or a straight-run intermediate fraction, and contains normal paraffins, isoparaffins, naphthenic hydrocarbons, and aromatic hydrocarbons. These compositions differ depending on where the crude oil is produced. In order to produce the solvent used in the present invention,
Although a fraction obtained from any crude oil can be used, it is preferable to use a fraction obtained from a crude oil rich in naphthenic hydrocarbons and naphthalenes.

The fraction is then subjected to hydrogenation. The straight-run fraction obtained by distilling crude oil generally contains sulfur compounds, nitrogen compounds, and olefin compounds as impurities. The fraction obtained by separating normal paraffins from the fraction containing such sulfur compounds, nitrogen compounds, and olefin compounds has a strong odor and is unsuitable for use. It is necessary to do this. Moreover, the above-mentioned impurities interfere with the normal paraffin separation process. Particularly when an adsorption separation method using synthetic zeolite is used, it must be removed because it significantly reduces the activity of the adsorbent. The above purification step is carried out in order to remove the aforementioned sulfur compounds, nitrogen compounds, and olefin compounds contained in the straight distillation fraction. Hydrorefining is carried out by conventional methods. That is, as a catalyst, Co-Mo type, Ni-Mo type, Ni-G
o-1yl.

system, N1-W photocatalyst, etc. are used, and the reaction temperature is 260-4
30℃, pressure 20-100 K9/d, LIISV
The test is carried out under the following conditions: O, 5 to 10, and hydrogen ratio of 50 to 50, 7113/kN.

In this hydrogenation II production process, in addition to desulfurization, denitrification, and deolefin reactions, some aromatic hydrocarbons are hydrogenated, some naphthalenes are converted to tetralins, and some Alkylbenzene changes to naraane. The impurities contained in the fraction after hydrorefining are desirably: total sulfur (1 DI) or less, total nitrogen (11) DI or less, and bromine index 100/10009. As a method for separating normal paraffins, conventional methods such as a crystallization separation method, a urea adduct method, and an adsorption separation method using synthetic zeolite can be used. An adsorption separation method using synthetic zeolite is a particularly preferred method, and the Isosieve method from 000 Company and the Molex method from UOP Company are preferably used. It is necessary for the performance of the solvent of the present invention that the residual normal paraffin in the raffinate oil be 10% by weight or less. The normal paraffin raffin oil thus obtained contains essentially naphthenic hydrocarbons and isoparaffins.
In addition, it consists of tetralin hydrocarbons. The raffinate can be used as it is as a solvent in the present invention, but
If necessary, it can be further separated by distillation and used as a fraction having an appropriate boiling point range. The solvent of the present invention can be any of the main solvents currently used as color forming agent solvents for pressure-sensitive copying materials, such as those having at least two non-condensed or integrated aromatic rings and having a boiling point of 260''G. When used in combination with the above-mentioned aromatic hydrocarbon oils or chlorinated paraffin oils, the solubility of the color forming agent and the solubility of the phenolic resin as a color developer will be significantly improved as a result of the synergistic effect, resulting in the improvement of pressure-sensitive copying materials. It exhibits particularly excellent performance in terms of improved coloring performance and economical effects.

The hydrocarbon oil having two or more non-condensed or integrated aromatic rings is desirably one with a boiling point (calculated at normal pressure) of 260°C or higher; diisopropylphenylethane, isopropylphenyl-phenylmethane,
Phenylnibutylphenylmethane, benzylxylene,
Alkylnaphthalenes such as diarylalkansopropylnaphthalene such as benzyl-ethylbenzene, alkyl or cycloalkylbiphenyls such as isobutylbiphenyl, sec-butylbiphenyl, and cyclohexylbiphenyl, partially hydrogenated terphenyl (trade name HB-4)
0), triarylsialkane such as dibenzyltoluene, di(α-methylbenzyl)benzene, di(α-methylbenzyl)xylene, dibenzylbenzene, triarylalkannaphthalene such as diphenyl xylyl butane, α-methylbenzyl Naphthyl aryl alkanes such as naphthalene, penzyl ribtraline, α-
Examples include aryl alkylated products of partially hydrogenated condensed ring aromatics such as methylbenzyltetralin.

It is desirable that the aromatic hydrocarbon oil used in combination has a maximum of 3 aromatic rings, and if it is 4 or more, the viscosity is high, so even if the solvent of the present invention is used in combination, the coloring properties are low and it is not suitable for practical use.

The chlorinated paraffin oil is made from normal paraffin, and has 10 to 14 carbon atoms per molecule.
Those having a chlorine content of 30 to 60 ff1% are preferably used.

When the main solvent and the solvent used in the present invention are used in combination, the u ratio is preferably 5 to 40% of the solvent used in the present invention to 60 to 95% of the main solvent, more preferably 5 to 30% to 70 to 9.
It is 5%. If the amount of the solvent of the present invention is less than 5%, the improvement in the color development performance of the resulting pressure-sensitive copying material or the economic effect of the combined use will be poor. Moreover, if it exceeds 40%, the solubility of the color former decreases, so the stability of the color former solution decreases, and recrystallization and precipitation of the color former may occur. In addition, at 40% or more,
When a phenolic resin is used as a color developer, the solubility of the resin decreases, and coloring performance tends to decrease as well.

The copying material of the present invention is suitably produced using a solution in which an electron-accepting color developer and a colorless electron-donating color former that develops color when in contact with the developer are dissolved in the solvent used in the present invention. Ru.

Examples of electron-accepting color developers include bentonite, zinc oxide, titanium oxide, kaolin, clay, activated clay, acid clay, zeolite, talc, colloidal silica, and phenolic resins whose use has been increasing in recent years. There are polymer materials such as

Further, as the colorless electron-donating coloring agent that develops color upon contact with the color developer, triarylmethane-based compounds, diphenylmethane-based compounds, xanthine-based compounds, thiazine-based compounds, spiropyran-based compounds, and the like are used. More specifically, methyl violet, crystal violet, malachite green, rhodamine B, 0-hydroxyben 1f acetophenone, Michler's hydrol derivative, pyromellitic acid indole derivative, 70 run derivative, azo blue black, Nige Oshin, oil Examples include Black, Sudan m, Sudan ■.

The above coloring agent is used by being dissolved in the solvent used in the present invention, and its dissolution (a is about 0.5.-15% by weight).

Taking a pressure-sensitive copying material, such as pressure-sensitive copying paper, as an example of the copying material of the present invention, and describing its general manufacturing method, a solution of the above coloring agent dissolved in the solvent used in the present invention is mixed with gelatin and gum arabic. The oil is emulsified and dispersed in an aqueous solution, and then a gelatin film is formed around the emulsified oil droplets using a coacervation method. Alternatively, interfacial polymerization method, In-3i
A method of forming a resin film by tu polymerization or the like is also often used.

Pressure-sensitive copying paper is manufactured by applying the Kabrel emulsion in the form of fine oil droplets thus produced to paper, and then applying the color developer in a layer on the surface of the paper opposite to the applied surface, or on the applied surface.

[Example 1] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples unless it departs from the gist of the present invention.

Fruit Pus Example (a) Solution 1 used in the present invention? Production of I obtained by distilling Minas crude oil, boiling point range 179-260
The kerosene fraction at ℃ was subjected to hydrorefining. Hydrorefining is Ni
- Temperature: 280℃, pressure: 80K9 using W photocatalyst,
The test was carried out under the following conditions: 1-H3V-1, hydrogen ratio 30 ON, silence/M music. The resulting hydrotreated oil had a sulfur i ppm or less, a nitrogen content of 11) or less, and a bromine index of 40.

The hydrotreated oil was then treated using Linde Molecular Sieve 5Δ to separate normal paraffins. Separation conditions: temperature 180°C, pressure 2FVg, LIISV = IF. This extracted residual oil is then distilled to a boiling point range of 183~
The 230°C fraction is used as the solvent (1) of the present invention. In the same distillation process, a fraction having a boiling point of 210 to 245 DEG C. is obtained, and this is referred to as the solvent (2) of the present invention. These properties are also shown in Table 1.

Table 1 Solvent of the present invention Distillation properties of the solvent of the present invention ("C) First distillation 183
210 end point 2
30 245 Composition (wt%) Normal paraffins 2-physoparaffins 2024 Naphthenic hydrocarbons 6654 Tetralin hydrocarbons 911 Aromatic hydrocarbons 34 Sulfur content (ppn+) 1 or less 1 or less Nitrogen content (ppm) 1 or less 1 or less viscosity(
C, S, 840℃> 1.3 1.
9 (a) Solubility test of coloring agent Crystal violet lactone for blue color was used as a coloring agent, and the influence of the solvent of the present invention on dye solubility was investigated. The test method is as follows. That is, phenylnixylethane "8 stone Hysol 5A" was used as the main solvent.
Using S-296J (trade name, manufactured by Nippon Petrochemical Co., Ltd.), a coloring agent was added in 1% increments from 4% to 7% to a mixed solvent of various solvents, dissolved by heating, and then left at room temperature. death,
The phenomenon of recrystallization was observed. The results are shown in Table 2. Table 2
Among them, phenyl-xylylethane alone is a reference example, and isoparaffin solvent [Isobal] (trade name) and kerosene are comparative examples.

As is clear from Table 2, unlike conventional auxiliary solvents, the solvent used in the present invention does not significantly reduce the solubility of the color former.

Table 2 0 Complete dissolution Δ A small amount of suspended matter X There are suspended matter and precipitate Crystal violet lactone was added as a coloring agent to the W%j solvent.
．． It was dissolved at 5% to form a color former solution.

The solution was then microencapsulated.

Microencapsulation was performed using urea and formalin.
A conventional method using -5 itu polymerization was used. A paste and a protective material were added to the obtained microcapsule emulsion, and the mixture was coated on high-quality paper using a Soy 1 arbor to obtain a top sheet of pressure-sensitive copying paper. In addition, a sheet of paper coated with phenol-formaldehyde resin as a color developer was prepared.

(Wub) Diisopropylnaphthalene as the main solvent
KHC-RJ (manufactured by Kureha Chemical Industry Co., Ltd., product name)
Solvent (1) used in the present invention produced in (a) using
A pressure-sensitive copying paper was prepared in the same manner as in (Ua).

(WuC) Pressure-sensitive copying paper was prepared in the same manner as (Wa) by using sec-butylbiphenyl as the main solvent and mixing the solvent produced in (A).

(Wood) Di(α-methylbenzyl)benzene was used as the main solvent. The solvent produced in (a) was mixed with this to prepare pressure-sensitive copying paper in the same manner as in (u-a).

For each case of (Wood a) to (Wood d), top sheets were made in the same manner using an isoparaffin solvent (trade name [Isoparu 1 ('')) in combination with each main solvent for comparison.

In the case of (Wa), a comparison was also made when kerosene was used in combination.

(1) Measurement of color development speed and density The same load was applied to each paper combination to develop color.

The reflectance of the lower paper 1 minute and 1 hour after loading ffi was measured using a reflection spectrophotometer.

Table 3 shows the results when phenyl-xylylethane was used as the main solvent. As can be seen from the table, unlike conventional paraffinic solvents or kerosene, the solvent used in the present invention has the effect of improving coloring performance without impairing it.

Further, Table 4 shows the results when diisopropylnaphthalene was used as the main solvent. In the case of diisopropylnaphthalene, the effect of improving the coloring performance of the solvent used in the present invention is more remarkable than in the case of phenyl-xylylethane.

Further, Table 5 shows the results when 5ec-butylbiphenyl or di(α-methylbenzyl)benzene was used as the main solvent. In both cases, it can be seen that the color development performance is improved by using the solvent of the present invention. In particular, when di(α-methylbenzyl)benzene, which is a three-ring aromatic hydrocarbon, is used as the main solvent, the degree of improvement is more remarkable than that of phenyl-xylylethane.

Furthermore, Table 6 shows the binding results when the test was conducted in the same manner as in Example 1 and Example 2, using chlorinated paraffin oil [Empara Niichi 45] (manufactured by Ajinomoto Co., Inc., trade name) as the main solvent. It can be seen that in this case as well, the coloring performance was improved by using the solvent of the present invention in combination.

Table 4 [Effects of the invention] The present invention, which uses a fraction having a specific boiling point range and a specific component composition as a solvent for a coloring agent, has the following characteristics compared to copying materials using conventional solvents. and has an effect.

That is, by using the solvent of the present invention alone or in combination with various main solvents conventionally used as dye solvents for pressure-sensitive copying materials, (1) the solvent used in the present invention can be produced at low cost; Pressure-sensitive copying materials can be produced at a lower cost than when expensive two- or three-ring aromatic hydrocarbon oils are used alone,
Excellent economic effect.

(2) Compared to the case where conventionally used isoparaffin, norparaffin, kerosene, linear alkylbenzene, etc. are used in combination with the main solvent, the solubility of the color former is less likely to be lowered. Further, even when a polymeric material such as a phenolic resin is used as a color developer, the coloring performance is hardly deteriorated, and when the main solvent has a high viscosity, the coloring performance is improved by the combination.

(3) Unlike when using aromatic hydrocarbons such as low-boiling point alkylbenzenes and alkylnaphthalenes, there is less ζ odor and less toxicity.

(4) Since the inexpensive extracted residual oil obtained by separating industrially useful normal paraffin from kerosene can be used as the solvent of the present invention, pressure-sensitive copying materials can be produced at low cost and economically. The effect is great.

(5) According to the present invention, it is possible to utilize H-lead residual oil after separating normal paraffin, which has not been valuable as a fuel in the past, to a high degree, which has great industrial value.

Claims (5)

[Claims] (1) In a copying material using a solution in which an electron-accepting color developer and an electron-donating color former that develops color when in contact with the developer are dissolved, the solvent of the solution is heated to a temperature of 160 to 260°C. (converted to normal pressure) and consists essentially of naphthenic hydrocarbons, isoparaffins, and tetralin hydrocarbons, with a naphthenic hydrocarbon content of 50 to 85% by weight, The content of tetrari hydrocarbons is 2 to 15% by weight, the content of isoparaffins is 10 to 40% by weight, the content of alkylbenzenes and alkylnaphthalenes is 5% by weight or less, and the content of normal paraffins is 10% by weight or less. A copying material characterized in that it consists of a hydrocarbon mixture oil. (2) The copying material according to claim 1, wherein the hydrocarbon mixture mainly contains components within a boiling point range of 180 to 230°C. (3) The copying material according to claim 1, wherein the hydrocarbon mixture mainly contains components within the boiling point range of 210 to 250°C. (4) In a copying material using a solution in which an electron-accepting color developer and an electron-donating color former that develops a color when in contact with the developer are dissolved, the solvent is (A) 160°C to 260°C. Mainly contains components within the boiling point range of °C (converted to normal pressure), substantially consists of naphthenic hydrocarbons, isoparaffins, and tetralin hydrocarbons, and has a naphthenic hydrocarbon content of 50 to 80% by weight , content of tetralin hydrocarbons from 2 to 5% by weight, content of isoparaffins from 10 to 40% by weight, content of alkylbenzenes and alkylnaphthalenes of 5% by weight or less, and content of normal paraffins of 10% by weight or less. 5 to 40% by weight of a hydrocarbon mixture oil, and (B) one type of hydrocarbon oil or chlorinated paraffin oil having a normal boiling point of 260° C. or higher having at least two non-condensed or condensed aromatic rings; A copying material comprising 60 to 95% by weight of two or more types. (5) The copying material according to any one of claims 1 to 6, wherein the copying material is a pressure-sensitive copying material.