JPS61146592A - Pressure-sensitive duplicate paper - Google Patents

Abstract

PURPOSE:To obtain a pressure-sensitive duplicate paper capable of forming color pictures having high color density and excellent light resistance by using a specific fluoran compound as a color-forming agent. CONSTITUTION:A color-forming agent containing a fluoran compound of the formula (I), where R1 is H, a C1-C8 alkyl or tetrahydrofurfuryl group, R2 is H, Cl, F, or a lower alkyl, R3 is a lower alkyl or phenyl group with or without substitution group, and R4 is a lower alkyl or benzyl group with or without substitution group. is used. As a condensation agent to be used in the manufacture of the color-forming agent, conc. sulfuric acid or acetic anhydride may be cited. A pressure-sensitive duplicate paper is obtained by coating the color- forming agent or a mixture of the color-forming agent with other color-forming agents on a supporter.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to pressure sensitive copying paper. More particularly, the present invention relates to pressure-sensitive copying paper using a novel fluoran compound having a tetrahydrofur7lylamino group at the 6-position as a color former.

(Prior Art) Conventionally, color formers such as Malachi F green lactone, benzoylleucomethylene blue, crystal violet lactone, rhodamine B lactam, 2-substituted 1ζ and 6-substituted aminofluorane, 3-methyl-2
, 2-spiro (benzo(f)chromene) or a mixture thereof, and an adsorbed or reactive compound (hereinafter referred to as a color developer) that develops a color upon contact with this color former, such as acid clay,
Clay minerals like activated clay, attapulgide, zeolite, pentonite, kaolin, succinic acid, tannic acid,
Pressure-sensitive copying papers that utilize coloring reactions with organic acids such as gallic acid, phenolic compounds, and acidic polymers such as phenol-formaldehyde resins are generally well known (e.g., U.S. Pat. No. 2,505,470). ,2,505,
No. 471, ZSO 翫 No. 489, No. 2.548, 366,
λ712.507, 2.73 false 456, 2.73 exposure 457 and 3.41a250).

Here, if we define the color former and color developer electronically,
A color former is a substance that generates color by donating electrons or accepting protons, and a color developer is a substance that accepts electrons or donates protons.

The conditions required for coloring agents for pressure-sensitive copying paper include fast coloring speed, high coloring density, the desired hue of the coloring dye, and excellent light and heat resistance of the dye. be. However, for example, crystal violet lactone is known as a coloring agent that develops a blue color, but its light resistance is insufficient, and there is a desire for a coloring agent that satisfies the above-mentioned requirements.

(Objective of the Invention) An object of the present invention is to provide a pressure-sensitive copying paper that forms a color-forming layer that has a fast coloring speed, a high coloring density, and good light resistance.

(Structure of the Invention) The present invention which achieves the above object has the general formula CI) (wherein R1 is hydrogen, an alkyl group having 1 to 8 carbon atoms, a tetrahydrofurfuryl group, a substituted or unsubstituted phenyl group, or a cyclic alkyl group). R1 represents hydrogen, chlorine, fluorine, a lower alkyl group, [1 flukoxy group, lower alkoxyalkyl group, phenyl group, or benzyl group, R3 represents a lower alkyl group, substituted or unsubstituted phenyl group, substituted or unsubstituted 4 represents a lower alkyl group, a substituted or unsubstituted benzyl group, a phenyl group, a phenyl group substituted with chlorine, fluorine, a lower alkyl group, a 1-syl group, or a hydrogen atom. The present invention relates to a pressure-sensitive copying paper characterized in that it has a color forming agent layer containing a fluoran compound represented by () on a support.

The fluoran compound represented by the general formula (I) according to the present invention is a colorless or slightly colored solid that is stable in the atmosphere, and when it comes into contact with an acidic substance, it immediately forms a dark red to black pigment with Vca. However, this colored pigment has excellent light resistance and heat resistance, so it has sufficient utility value.

The fluoran compound represented by the above general formula (1) according to the present invention is produced by the following method.

Aniline derivatives represented by general formula (II) (wherein R represents a hydrogen atom, an acetyl group, or a lower alkyl group, and Ra #Rs e Ra has the same meaning as the above definition) and general formula [1] υ (wherein R1 has the same meaning as defined in general formula (1)) is reacted with a benzophenone compound represented by the following formula (R1 has the same meaning as defined in general formula (1)) in the presence of concentrated sulfuric acid at a temperature of 80° C. for several hours. After the reaction, the reaction mixture is added to water, sodium hydroxide is added to adjust the pH to 8-10, and the precipitate is collected by filtration. Add toluene and a 5-10% aqueous sodium hydroxide solution to the cake, stir under reflux for 1-3 hours, separate the toluene layer, collect it, wash with water, condense, and collect the precipitated crystals by filtration. do. By drying the crystals, a slightly colored fluoranated metal having a tetokuhydrofurfuryl group at the 6-position represented by the general formula (1) is obtained with high purity and high yield. If necessary, 1 toluene, 1 setone,
Recrystallize from volatile organic solvents like butyl acetate, hexane, etc.

Condensing agents used in the method for producing the color former according to the present invention include concentrated sulfuric acid, acetic anhydride, phosphoric acid, polyphosphoric acid, phosphorus oxychloride, and zinc chloride. A preferred method for production is to use concentrated sulfuric acid, which is both a solvent and a condensing agent, such as a benzophenone compound represented by the above general formula [Otori].

The pressure-sensitive copying paper of the present invention may contain the above-mentioned color formers alone or in combination, or together with other color formers, such as diaryl-lukanes such as mono-rukylated naphthalene, mono-rukylated diphenyl, mono-rukylated diphenylmethane, alkylated Synthetic oils such as terphenyl, vegetable oils such as cotton oil and castor oil, animal oils, mineral oils, or mixtures of these oils can be dissolved in solvents,
It can be obtained by dispersing it in a binder or containing it in microcapsules, and then applying it to a support such as paper, plastic sheet, resin-coated paper, or the like.

The amount of color former depends on the desired coating thickness, the form of pressure-sensitive copying paper,
It is determined by the capsule manufacturing method and other conditions. When encapsulating a coloring agent in a capsule, U.S. Pat.
No. 00,457 and 2.80 Q45 B Specification K
Method using coacervage 1 of hydrophilic colloidal sol loaded with le, British Patent No. 86S 797, 1.09
The interfacial polymerization method described in No. 1.076 may be used.

Variant examples of color developers that can be applied to the pressure-sensitive copying paper of the present invention include clays (for example, acid clay, activated clay, attapulgite, kaolin, etc.), phenolic resins, and polyvalent metal salts of aromatic carboxylic acids. etc. can be given. Specifically, the phenolic resin is a phenol-aldehyde polymer (so-called novolak type) and a phenolacetylene polymer. Polyvalent metal salts of aromatic carboxylic acids are
For example, U.S. Pat.
No. 92, No. 4954.070, No. 984292,
It is described in Japanese Patent Application No. 55-25158.

The aromatic carboxylic acid in the polyvalent metal salt of an aromatic carboxylic acid is preferably one having a hydroxyl group at the ortho or para position with respect to the carboxy group, and salicylic acid derivatives are particularly preferred; It is particularly preferable that at least one of them has a substituent such as an alkyl group, an aryl group, an aralkyl group, and the total number of carbon atoms of the substituents is 8 or more. Among the polyvalent metal salts mentioned above, zinc salts are particularly preferred.

Next, a typical production example of a fluoran compound having a tetrahydrofurfuryl 1-mino group at the 6-position according to the present invention will be shown below.

Production Example 1 2-1 Nilino 3-Methyl-6-N-ethyl-N-tetrahydrofurfuryl-Norfluorane (Compound 41) 2-Hydroxy-4-N-ethyl-N-tetrahydrofurfuryl in 150f of 95% sulfuric acid Amino-2'-carboxy-benzophenone 146F73Q was completely dissolved at a temperature of about 5°C, and then 1.5t of sidiphenylamine in 2-methyl-4-meth was added and dissolved at a temperature of 5 to IOC.
The reaction was allowed to proceed for 0 hours. After the reaction, 1 portion of ice water was added to the reaction mixture, followed by 10% aqueous sodium hydroxide solution.
The pH was adjusted to 7-8, and the precipitate was collected by filtration. To the cake were added 450 mm of toluene and 340 mm of a 10% aqueous sodium hydroxide solution, and the mixture was stirred under reflux for 2 hours, separated from the toluene layer, washed with water, concentrated to dryness, and solidified by adding methanol. This solidified product was dried and a pale pink 2-1-nilino-
3-Methyl-6-N-ethyl-N-tetrahydrofurfuryl-based nofluorane 17.8 F was obtained. The melting point of this product was 165#167°C. In addition, the λmax and molecular extinction coefficient of this material in 95% acetic acid are 452 nm (t944×10) and 594 nm (1
,949X10') and ivy.

A solution obtained by dissolving this substance in toluene was colorless, and the silica gel quickly developed a color to give it a black color.

According to Production Example 1, a fluoran compound having a tetrahydrofurfurylamino group at the 6-position [Compound/162-A2
6) was manufactured. The structural formulas of these compounds and the color hues developed on silica gel are summarized in the following table.

Table 1 (Examples of the Invention) Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto in any way.

Example compound/2-anilino-3-methyl-6-N-n-butyl-N-tetrahydrofurfurylamino-fluorane, 18 (parts by weight, the same applies hereinafter) represented by I64 was dissolved in 50 parts of fluorinated naphthalene in alcohol. I let it happen. This solution was added to 50 parts of water in which 6 parts of gelatin and 4 parts of gum arabic had been dissolved, with vigorous stirring, to emulsify it to form oil droplets with a diameter of 1 μm to 10 μm, and then 250 parts of water was added thereto. Add acetic acid little by little to bring the pH to about 4 and cause coacervation.
A wall of FC gelatin and gum arabic was created around the oil droplet, formalin was added, the pH was raised to 9, and the wall was hardened. The microcapsule dispersion obtained by applying this pressure was applied to paper and dried. This pressure-sensitive copying paper had excellent storage stability.

We are busy evaluating the characteristics of this pressure-sensitive copying paper.
Pressure equivalent to writing was applied to clay paper, resin paper, and organic acid salt paper. The recording paper used is as follows.

Clay paper 20 parts of acid clay, 112 parts of sodium hexametaphosphate, and 80 parts of water were dispersed using a homogenizer for 5 minutes, and then 50 parts of acid clay was dispersed for 5 minutes.
% styrene butadiene latex was added to form a clay dispersion.

This dispersion was coated on high-quality paper to give a dry solid content of 52 to 52, to obtain clay paper.

20 parts of resin paper p-phenylphenol formalin a compound, 291,100 parts of cal carbonate, and 600 parts of a 2% polyvinyl 1-l aqueous solution were dispersed in a ball mill to obtain a phenol resin dispersion.

This dispersion was coated on high-quality paper with a dry solid content of 5 f/v? It will be part 5! I made a cloth and obtained resin paper.

Organic acid salt paper An organic acid salt paper was obtained in the same manner as in the production of the resin paper except that zinc 3,5-α-methyl-benzylsalicylate was used instead of the p-phenylphenol formalin condensate.

When the copying paper containing Compound 4 as a coloring agent was stacked with each recording paper and pressure was applied, a reddish-black to black printed image was instantaneously obtained. This printed image had a high fresh density of 1.10, an excellent original value of 78%, and excellent heat resistance.

Fresh density: Dissolve 2% of the coloring agent in toluene and apply it on clay paper. Macbeth reflection + 11fl
! This is a value measured using a meter (filter, Ratsuten Gin 106).

Lightfastness value: The color density was measured after irradiation with a fade, o, meter for 3 hours, and the value was determined by the following formula.

Fresh Concentration IIO In place of the fluoran compound A4 used as a coloring agent in Examples, the compound obtained in Production Example 1 (Shoulder 1) and the compounds shown in Table 1 /I&2 to Shoulder 26 (however /I64) were used.
A pressure-sensitive copying paper was prepared using the same *KL/ method as in Example. The color hues of these pressure-sensitive copying papers on clay paper, resin paper, fresh density and light fastness values on clay paper were measured and are shown in the following table.

In addition, crystal violet lactone (CVL), which is a coloring agent often used in general pressure-sensitive copying paper, and
N,N-dibenzylamino-6-diethylazunofluorane (DBF) is expressed as PIAf11 on directly cooled copy paper.The various color phases of each compound on organic acid salt paper are the same as those on resin paper. Since the color development of the compound was the same as the various phases,
Description omitted.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, the fluoran compound represented by the general formula (1) is used as a color former and is directly cooled. A pressure-sensitive copying paper that forms a coloring layer is obtained.

Hodogaya Chemical Industry Co., Ltd.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [I] (In the formula, R_1 is hydrogen, an alkyl group having 1 to 8 carbon atoms, a tetrahydrofurfuryl group, substituted or unsubstituted phenyl group or a cyclic alkyl group, R_2 represents hydrogen, chlorine, fluorine, a lower alkyl group, a lower alkoxy group, a lower alkoxyalkyl group, a phenyl group or a benzyl group, and R_3 represents a lower alkyl group, a substituted or unsubstituted phenyl group, Represents a substituted or unsubstituted benzyl group or a hydrogen atom, and R_4 represents a lower alkyl group, a substituted or unsubstituted benzyl group, a phenyl group, a phenyl group or a hydrogen atom substituted with chlorine, fluorine, a lower alkyl group, or an acyl group. 1. A pressure-sensitive copying paper comprising, on a support, a color forming agent layer containing a fluoran compound represented by: