JPH0247085A - Pressure sensitive copy material - Google Patents

Abstract

PURPOSE:To obtain a pressure sensitive copy material having excellent coloring performance and a low cost by combining specific solvent and specific developer. CONSTITUTION:5-50vol.% of one or more types of alkyl benzene having 3cSt or less of viscosity at 40 deg.C of solvent of solution and 150 deg.C of boiling point of normal pressure conversion, and 50-95vol.% of aromatic hydrocarbon having at least to noncondensation or condensation type aromatic ring having 260 deg.C or higher of boiling point of normal pressure conversion, 3cSt or more of viscosity at 40 deg.C and/or chlorinated paraffin oil having 3cSt or more of viscosity of 40 deg.C are contained. A developer is selected from a group consisting of aromatic carboxylic acid, its polymer, its metal salts, polyvalent metallized carboxyl modified terpenephenol resin and its derivatives as well as their mixtures.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure-sensitive copying material that is inexpensive and has an excellent color development speed.

[Prior Art] Conventionally, a colorless electron-donating coloring agent (hereinafter referred to as "coloring agent") is incorporated in a microcapsule film in a solution state and applied to one side of paper, and the same is applied to another side of the paper. Electron-accepting substances such as carboxylic acids and acidic inorganic materials that react with color formers to develop color (hereinafter referred to as "color developer") are applied, and when used, these surfaces are stacked facing each other. Recording materials in which copies are recorded by pressing and pressing together, ie, pressure-sensitive copying materials, are well known.

The copy recording mechanism of this type of recording material breaks the microcapsule film using pressure such as writing pressure or typing pressure, releases a coloring agent solution, and applies the coloring agent to the surface of the paper on which the coloring agent is placed facing each other. It develops color when it comes into contact with a coloring agent.

Recording materials are also known in which coating materials such as microcapsules and color developers having this type of coloring function are coated on one side of a sheet of paper.

The color former solution used in these recording materials is a solution in which an electron-donating color former is dissolved in one or more hydrophobic solvents. The hydrophobic solvent used here must meet the following requirements. In other words, ■ It must be non-toxic ■ It must have no unpleasant odor ■ It must be colorless or very pale in color ■ The coloring agent must have good solubility and the solution must be stable ■ It must be easy to microencapsulate ■ The microcapsules have storage stability. ■ They do not interfere with the color reaction and the color development rate is fast. ■ There is no smearing in the colored image and clear colored images can be obtained even after long-term storage. ■ They are inexpensive.

Conventionally, as a solvent for this type of recording material, aromatic hydrocarbon oils having multiple aromatic rings such as diallyl alkanes such as phenylquinlylethane and phenylethyl phenylethane, alkylnaphthalenes, alkyl biphenyls, and partially hydrogenated terphenyls have been used. , or chlorinated paraffin. However, these solvents are expensive and
Moreover, the color development speed of the obtained pressure-sensitive copying material is not necessarily satisfactory.

[Problems to be Solved by the Invention] The present invention solves these problems of conventional pressure-sensitive copying materials, and provides a pressure-sensitive copying material that has excellent color development performance and is inexpensive.

That is, the pressure-sensitive copying material of the present invention is obtained by a specific combination of a specific solvent and a color developer that satisfy the above-mentioned properties, and in particular overcomes the drawbacks of conventional pressure-sensitive copying materials. The present invention provides a pressure-sensitive copying material with improved low-temperature color development speed.

[Means for Solving the Problems] That is, the present invention provides a pressure-sensitive copying material using a color former solution formed by dissolving an electron-accepting color developer and an electron-donating color former that develops a color when in contact with the color developer. The solvent of the solution is (a) one or more alkylbenzenes having a viscosity at 40°C lower than 3 cSt and a boiling point equivalent to normal pressure of +50°C or higher at 5 to 50°C (b) normal pressure. Aromatic hydrocarbons with a reduced boiling point of 280°C or higher and a degree of viscosity at 40'C of 3 cst or higher and a small number (both of which have 2) of non-fused or fused aromatic rings and/or a viscosity of 3 cst at 40'C 50 to 95% by volume of the above chlorinated paraffin oil; The present invention relates to a pressure-sensitive copying material characterized in that the material is selected from the group consisting of mixtures thereof.The present invention will be explained in more detail below.

The viscosity at 40°C in item (a) above is 3 cSt
Examples of alkylbenzenes that are smaller and have a boiling point of 150° C. or higher when converted to normal pressure include mono- or polyalkylbenzenes. In particular, alkylbenzenes whose alkyl groups have a total number of carbon atoms of 5 to 9 are preferred from the viewpoint of coloring performance and odor.

Alkylbenzenes with a boiling point below 150"C are not practical due to their odor. Preferably, alkylbenzenes with a boiling point of +70"C or higher are preferred.The viscosity of the hydrocarbon oil must be less than 3 cst, 3c
If it is higher than St, the improvement in coloring properties is small or not observed, which is not preferable. Hereinafter, in this specification, unless otherwise specified, the boiling point refers to the boiling point in terms of normal pressure.

Examples of aromatic hydrocarbons having at least two non-condensed or condensed aromatic rings with a boiling point of 280° C. or higher and a viscosity of 3 cst or higher at 40° C. in item (b) above include phenylquinlylethane. , diarylalkane such as phenylethyl phenylethane, phenylcumylethane, phenyl sec-butyl phenylmethane, alkylnaphthalene such as diisopropylnaphthalene, alkyl or cycloalkyl biphele, moiety such as sec-butyl biphenyl, isopropyl bidiphenyl. Examples include hydrogenated terphenyl.

As the chlorinated paraffin having a viscosity of 3 cSt or more at 40° C., chlorinated normal paraffins obtained from kerosene fractions or gas oil fractions are used. The chlorinated paraffin is not particularly limited in terms of chlorine content, molecular weight, etc., as long as the viscosity is within the above range.

These can be used alone or in combination.

If the viscosity of the component (b) at 40° C. is less than 3 cSt, no improvement in coloring properties is observed. The upper limit of the viscosity is not particularly limited, but if the viscosity is too high, no synergistic effect can be seen by mixing the components in item (a) above, which is undesirable. From this point of view, the viscosity at 40°C is usually 100
cSt is used.

Furthermore, if the boiling point of an aromatic hydrocarbon having at least two non-fused or fused aromatic rings is less than 280'C, it will have a small molecular weight, resulting in a high vapor pressure (and a large odor). This is not desirable.

The viscosity at 40°C of the component in item (a) above is 3
Alkylbenzene smaller than cSt and also the above (b
) as a component with a boiling point of 2 G O”C or higher and 40
The mixing ratio of the aromatic hydrocarbon or chlorinated paraffin oil having at least two non-fused or condensed aromatic rings with a viscosity of 3 cSt or more at C or chlorinated paraffin oil is from 5 to
50% by volume, the latter 50-95% by volume, preferably 5-40% by volume of the former and 60-95% by volume of the latter.

If the former is less than 5% by volume, no improvement in color development is observed and no effect on price reduction is observed. Similarly, if the former exceeds 50% by volume, the solubility of the coloring agent decreases and is not practical.

The present invention requires the use of a color developer selected from the group consisting of aromatic carboxylic acids, polymers thereof, metal salts thereof, polyvalent metallized carboxy-modified terpene phenolic resins, derivatives thereof, and mixtures thereof. be.

Pressure-sensitive copying paper with excellent color development speed cannot be obtained even with the solvent composition of the present invention, such as novolac-type phenolic resin, which has conventionally been commonly used as a color developer in copying materials, especially pressure-sensitive copying materials. I can't get it.

Here, the aromatic carboxylic acid used as a color developer is an aromatic ring (
Examples of such aromatic carboxylic acids include salicylic acid derivatives such as 3,5-di(α
-methylbenzyl)salicylic acid, 3-(α-methylbenzyl)-5-(α,α9dimethylbennor)salicylic acid, 3-(4′-α).

α'-dimethylbenzyl)phenyl-5-(α,α1 dimethylbenzyl)salicylic acid, 3,5-di-tert-
Butylsalicylic acid, 3I5-di-tert-octylsalicylic acid, 3-cyclohexyl-5-(α,α1-dimethylbenzyl)salicylic acid, 3-phenyl-5-(α.

α1~dimethylbenzyl)salicylic acid, 3,5-di(α
, α1-dimethylbenzyl)salicylic acid and the like. Furthermore, aromatic carboxylic acids to which styrenes have been added, such as styrenated salicylic acid, are also included. Particularly preferred aromatic carboxylic acids are aromatic carboxylic acids having a total number of carbon atoms of 5 or more. However, when used as a cocondensation or copolymerization monomer described below, the number of carbon atoms is not particularly limited.

Further, condensation or co-condensation resins containing aromatic carboxylic acids, particularly salicylic acid, as condensation monomers can also be used as the color developer in the present invention. Examples of such co-condensed resins include co-condensed resins of salicylic acid and dialkoxyxylene, and polymers of salicylic acid and aldehydes. Dryalkylbenzene or the like can be further added to these as a co-condensation monomer.

Metal salts of these aromatic carboxylic acids or polymers thereof can also be used. Examples of raw metal salts include polyvalent metal salts such as zinc, aluminum, barium, tin, iron, calcium, and lead.

In addition, polyvalent metallized carboxyl-modified terpene phenol resins or derivatives thereof are obtained by condensing cyclic monoterpenes and phenols in the presence of an acidic catalyst, and then introducing carboxylation into this by a conventional method. Examples include polyvalent metallized carboxyl-modified terpene phenol resins obtained by For example, JP-A-Sho [12-1
As disclosed in Japanese Patent No. 948fi, phenol and α-pinene are condensed using a boron trifluoride catalyst, and the resulting co-condensed resin is then carboxylated by introducing carbon dioxide gas in the presence of metallic sodium, and further chlorinated. A polyvalent metallized carboxy-modified tellhene phenol resin is produced by polyvalent metallization with zinc or the like. In this case, polyvalent metals include zinc, aluminum, barium, tin, iron, calcium, lead, and the like. Zinc is preferred.

Aromatic carboxylic acids, polymers thereof, and metal salts thereof as color developers and polyvalent metallized carboxy-modified terpene phenol resins may be used in combination. This mixing can be carried out in a solvent or dispersion medium or by melt mixing.

Specific examples of color formers include 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (crystal violet lactone, hereinafter referred to as rCVL) as a triarylmechne color former;
3.3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3-(1,2
-dimethylindol-3-yl)phthalide, 3-(p
-dimethylaminophenyl) -3-(2-methylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-phenylindol-3-yl)phthalide, 3,3-bis- (1,2-dimethylindol-3-yl)-5-dimethylaminophthalide, 3
,3-bis-(l,2-dimethylindol-3-yl)-6-dimethylaminophthalide, 3,3-bis-(9
-ethylcarbazol-3-yl)-5-dimethylaminophthalide, 3.3-bis-(2-phenylindol-3-yl)-5-dimethylaminophthalide, 3-p-
Dimethylaminophenyl-3-(1-methylvirol-
2-yl)-6-dimethylaminophthalide and the like.

As a diphenylmethane coloring agent, 4,4'-bis-
Dimethylaminobenzhydrin benzyl ether, N-
Halophenylleucoauramine, N-2,4゜5-IJ
Examples of color formers based on alxanthene such as chlorophenyl leuco auramine include rhodamine B-anilinolactam, rhodamine B (p-nitroanilino)lactam, rhodamine B (p-chloroanilino)lactam, 3-dimethylamino-6-methoxyfluoran, 3-diethylamino-
7-methoxyfluorane, 3-noethylamino-7-chloro-6-methylfluorane, 3-noethylamino-7
-(acetylmethylamine)fluoran, 3-diethylamino-7-(dibenzylamino)fluoran, 3-diethylamino-7-(methylbenzylamino)fluoran, 3-diethylamine-7-(chloroethylmethylamino)fluoran, 3- Examples include noethylamino-7-(diethylamino)fluoran, 3-diethylamino-6-methyl-7-anilinofluoran, and the like.

Examples of the thianone color former include benzoyl leucomethylene blue and p-nitrobenzyl leucomethylene blue.

As a spiropyran coloring agent, 3-methyl-spiro-
dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3.3'-cyclospirodinaphthopyran, 3-
Examples include benzyl-spiro-dinaphthopyran, 3-methyl-naphtho(3-methoxy-benzo)-spiropyran, and 3-propyl-suvirodibenzodibiran.

Taking the pressure-sensitive copying material of the present invention, such as pressure-sensitive copying paper, as an example,
To describe the general manufacturing method, the above coloring agent is mixed with 0.1~
A solution dissolved in the solvent composition of the present invention at a ratio of 10% by weight is emulsified and dispersed in a mixed aqueous solution of gelatin and gum arabic, and then a gelatin film is formed around the emulsified oil droplets by a coacervation method. Recently, Ir+-
In addition to the 5 ltu polymerization method, the interfacial polymerization method, and the like, a method of microencapsulating with a synthetic resin film is also widely used.

By applying the capsule emulsion of fine oil droplets produced by this method to paper, and applying the above color developer in a layer on the coated surface and the opposite side of the paper, a A pressure sensitive copying material is produced.

[Example] Next, the present invention will be explained by Examples, but the present invention is not limited to these Examples. The obtained CI, lI = CI5
A mixture of alkylbenzenes was used (viscosity at 40°C = 2.Ocst1 boiling point range 200°C or higher).

Using phenylxylylethane (boiling point 290-305°C, viscosity at 40°C = 5.1 cst) as an aromatic hydrocarbon oil having two aromatic rings, the above alkylbenzene was mixed, and a color former as shown below was added. A solution was obtained, and the stability of the color former solution and the speed of color development when used as pressure-sensitive copying paper were compared. Among these, solvent A-1 is a control example, and solvent A-1 is a control example.
2, A-E3 are comparative examples, and A-3 to A-5 are examples of the present invention.

The stability of the color former solution was determined by preparing a 5% solution of heated crystal violet lactone (CCVL) and observing no precipitation of CYL crystals when it was left at room temperature for 5 hours. The color development rate was measured by the following method. That is, a solution containing 5% CYL was treated with In-5 using urea and formalin.
The resulting microcapsule emulgene was microencapsulated by the LTU polymerization method, and a paste and a protective agent were added thereto, and the mixture was coated on high-quality paper using a Mayer bar to obtain the top sheet of pressure-sensitive copying paper. 3I5-di(α-methylbenzyl)salicylic acid zinc salt was coated on the base paper and a condensation resin of phenol and α-pinene was carboxylated with carbon dioxide gas, and the zincated paper was produced by further reacting with zinc chloride. A bottom paper coated with a carboxy-modified terpene phenol resin was prepared. The microcapsule-coated surface of the top paper was overlapped with the color developer on the bottom paper, and color was developed using an impact printing machine.

The reflectance of the lower paper was measured using a reflection spectrophotometer 3 seconds and 60 seconds after color development (after MI7 bombardment). I asked for 3 degrees. The ratio of the color density after 3 minutes to the color density after 60 minutes was defined as the color development rate. This measurement was carried out at -3°C. The results are shown in Table-1.

In addition, the color development speed described in the table is expressed as a ratio (relative value) to that in the case of phenylxylylethane alone. In the following experimental examples, the color development rate is expressed as a ratio (relative value) to the color development rate when the corresponding two-ring aromatic hydrocarbon is used alone.

As can be seen from Table 1, the solvent composition of the present invention has a faster color development rate and better stability of the color former solution than when phenylxylylethane is used alone.

1. As a two-ring aromatic hydrocarbon oil, noisopropylnaphthalene (boiling point 292-305°C, viscosity at 140°C: 6.
3 cst), the stability of the color former solution and the color development speed of the pressure-sensitive copying paper were determined in the same manner as in Experimental Example-A. The results are shown in Table-2. In the table, B-1 is a control example, B-2, B-
5 is a comparative example, and B-3 and B-4 are examples. Experimental example-
Similar to A, the solvent composition of the present invention is excellent in both color development speed and stability of the color former solution.

Hydrogenated terphenyl (boiling point 330-390°C, viscosity at 40°C = 24, Oc
st), the stability of the color former solution and the color development speed of the pressure-sensitive copying paper were determined in the same manner as in Experimental Example-A.

The results are shown in Table-3. C-1 is a control example, C-2 and C-
4 is a comparative example, and C-3 is an example. As in Experimental Example-A, the solvent composition of the present invention is excellent in both color development speed and stability of the color former solution.

1 per minute As a chlorinated paraffin oil, Ajinomoto Q'iJ'H's product name "Empara ni 1 45J (viscosity at 40°C = 5
1C3t), the stability of the color former solution and the color development speed of the pressure-sensitive copying paper were determined in the same manner as in Experimental Example-A. The results are shown in Table-4. In the table, D-1 is a control example, D-2 and D-4 are comparative examples, and D-3 is an example. As in Experimental Example-A, the solvent composition of the present invention was excellent in both color development speed and stability of the color former solution.

Souji 1 The following experiment was conducted as a comparative example.

As a two-ring aromatic hydrocarbon oil, phenylethyl phenylmethane (boiling point 290-295℃, viscosity at 140℃ 2
．． 7 cSt), the color development rate of the pressure-sensitive copying paper and the odor of the color former solution were determined in the same manner as in Experimental Example-A. The results are shown in Table-5. In the case of this experimental example, no improvement in color development rate was observed even if a hydrogenated low polymer with low viscosity was added, and the odor was also poor.

As a comparative example, a commercially available 7-borac type paraphenylphenol resin was used as the color developer, and phenylxylylethane was used as the two-ring aromatic hydrocarbon oil in the same manner as in Experimental Example-A.
The color development speed of pressure-sensitive copying paper was determined. The results are shown in Table-6. It can be seen that, contrary to the case where a zinc salt of a salicylic acid derivative or a polyvalent metallized carboxy-modified terpene phenol resin is used as a color developer, the color development rate decreases.

几１肚二Stop The following experiment was conducted as a comparative example.

A mixture of Cue~C,8 alkylbenzenes was used as the alkylbenzene. The viscosity of this product at 40°C is 3. ticSt 1 The boiling point was 280 to 300°C. Using phenylxylylethane as a hydrocarbon oil containing two aromatic rings, a color former solution was prepared in the same manner as in Experimental Example 8, and this was used. The color development speed of the pressure-sensitive copying paper was determined and the results are shown in Table 7.

It can be seen that even when alkylbenzene having a high viscosity is added, no improvement in color development rate is observed.

Fruit 1st seed 2nd grade - CI3-CI4 alkylbenzene obtained by alkyl reaction with 05-C6 olefin was used as the alkylbenzene. This product had a viscosity of 1.9St at 40°C and a boiling point of 200°C. Using phenylxylylethane as a hydrocarbon oil containing two aromatic rings, a color former solution was prepared in the same manner as in Experimental Example A, and the color development rate of pressure-sensitive copying paper using this solution was determined. are shown in Table-2. H in the table
-1 is a control example, and H-2 is an example. Experimental Example-A and Agitation The pressure-sensitive copying paper solvent used in the present invention has excellent color development speed. Although not shown, the stability of the color former solution using solvent H-2 was good.

As described above, the pressure-sensitive copying paper of the present invention has excellent color development speed at low temperatures.

Furthermore, as mentioned above, by combining a solvent composition containing a specific ratio of hydrocarbons with a specific viscosity and a specific color developer, dye solution stability and excellent color development performance at low temperatures can be obtained. However, this was unpredictable.

"Effects of the Invention" The solvent of the present invention has a color development rate superior to that of conventional aromatic hydrocarbon sole solvents. Furthermore, since the low polymers of propylene and butenes to be added thereto are inexpensive, an inexpensive pressure-sensitive copying material can be obtained according to the present invention.

(Margin below)

Claims (4)

[Claims] (1) In a pressure-sensitive copying material using a color former solution prepared by dissolving an electron-accepting color developer and an electron-donating color former that develops a color when in contact with the developer in a solvent, the solvent of the solution is , (a) the viscosity at 40° C. is smaller than 3 cSt, and
5 to 50% by volume of one or more alkylbenzenes with a boiling point of 150°C or higher when converted to normal pressure (b) Non-condensed or condensed type with a boiling point of 280°C or higher and a viscosity at 40°C of 3 cSt or higher when converted to normal pressure 50 to 95% by volume of an aromatic hydrocarbon having at least two type aromatic rings and/or a chlorinated paraffin oil having a viscosity of 3 cSt or more at 40°C, and the color developer is an aromatic carboxylic acid, A pressure-sensitive copying material characterized in that it is selected from the group consisting of polymers, metal salts thereof, polyvalent metallized carboxy-modified terpene phenolic resins, and derivatives thereof, and mixtures thereof. (2) The alkylbenzene has a boiling point of 170°C converted to normal pressure.
The pressure-sensitive copying material according to claim 1, which is as follows. (3) The pressure-sensitive copying material according to claim 1, wherein the aromatic carboxylic acid is a salicylic acid derivative. (4) The pressure-sensitive copying material according to claim 1, wherein the polyvalent metal is zinc.