JP3029052B2 - Pressure-sensitive copy paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive copying paper utilizing a color-forming reaction between an electron-donating color-forming agent and an electron-accepting color-developing agent, and is particularly excellent when applied to an optical character reading (OCR) device. The present invention relates to a pressure-sensitive copying paper exhibiting excellent characteristics.

[0002]

2. Description of the Related Art Pressure-sensitive copying paper (so-called carbonless paper) is
An electron-donating color developing agent such as crystal violet lactone and benzoyl leucomethylene blue (hereinafter referred to as a color forming agent) and an electron-accepting color developing agent such as activated clay, bentonite, a phenol resin, and a polyvalent metal salt of an aromatic carboxylic acid (hereinafter, referred to as a color developing agent). This is a copy paper that uses the color development reaction of a color developer), and is coated on the back of the base paper with microcapsules containing a color former made by a method such as phase separation, interfacial polymerization, or in-situ. And a lower paper with a developer applied to the surface of the base paper so that the respective coated surfaces face each other, writing the surface of the upper paper, printing with pressure by a typewriter, etc. to form a color image on the lower paper Copy paper to be formed.

If a large number of copies are desired, the above-described developer is applied to the surface of the base paper, and the microcapsules are applied to the back of the medium. Only inserted. A so-called self-coloring paper in which the microcapsules and the developer are formed on the same surface of the base paper as a laminated or mixed layer is also well known as one form of the pressure-sensitive copying paper. The demand for pressure-sensitive copying paper has been increasing remarkably in a wide variety of fields, for example, general slips, delivery slips, unified slips, contract documents, computer papers, etc., with the expansion of applications.

On the other hand, with the development of the information processing industry, office automation has progressed, and the rationalization of office work has been promoted. And OCR and O as one way of rationalization
2. Description of the Related Art MR equipment has become widespread, and in general companies, it is necessary to make main slips, such as order slips, sales slips, shipping slips, purchase slips, input / output slips, etc., slips suitable for OCR and OMR equipment. I have. Moreover, these slips require a large number of copies due to the necessity of an office system.

[0005]

Under these circumstances, there has been an increasing demand for the development of OCR slips using pressure-sensitive copying paper. However, the PCS value of the color image of the pressure-sensitive copying paper in the infrared region is 0.1. O which has a reading wavelength in the infrared region
There is a problem that a CR device functions as a dropout color and cannot be read. Also 600-70
Even for an OCR device having a reading wavelength in the visible region of 0 nm, there is a problem that the PCS value is only about 0.4 for the black color of the pressure-sensitive copying paper and reading is uncertain. In addition, the color density of pressure-sensitive copying paper may vary depending on the writing pressure (printing pressure), and color fogging may occur due to undesired pressure or environmental factors such as heat and humidity. In the development of paper, the properties peculiar to these pressure-sensitive copying papers are also a development difficulty.

[0006] Therefore, the present inventors have conducted intensive studies on the improvement of these difficulties, and as a result, used a color former having a specific structure as a color former and used as a wall film material of microcapsules containing the color former. When a synthetic polymer material is used, its particle size and film thickness are specified, and a specific color developer is combined with the material, an OCR device having a reading wavelength in the visible region of 600 to 700 nm becomes extremely difficult. It has been found that a pressure-sensitive copying paper exhibiting stable reading performance and having little change in color density and little color fog can be obtained, and the present invention has been completed.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a pressure-sensitive copying paper utilizing a color-forming reaction between an electron-donating color former and an electron-accepting color developer. It contains a bis-aminophenyl-azaphthalide derivative, a color former is encapsulated in a synthetic polymer microcapsule, the average particle size is 3 to 15 microns, and the average film thickness is 0.1 to 0.7. This is a pressure-sensitive copying paper having a micron diameter and using a zinc salt of a salicylic acid derivative as an electron-accepting developer.

[0008]

[Action] As an index indicating the degree of OCR readability,
Since there is the PCS (Print Contrast Signal) value mentioned above,
First, the PCS value will be described. That is, the PCS value is
It represents the degree of relative darkness between color printing and paper, and is expressed by the following equation. PCS = (Rw-Rp) / Rw Here, Rw indicates the maximum reflectance of a blank portion of the paper in the target area, and Rp indicates the maximum reflectance of printing at an arbitrary measurement point (P). And, in general OCR paper, PCS
The higher the value, the clearer the character identification and the higher the readability.

However, when pressure-sensitive copying paper is used as OCR paper, even if the PCS value of a color image (printing) is sufficiently high, changes in printing density due to pen pressure, discontinuity of printing,
If the printing blur occurs, the readability is greatly reduced. Therefore, the suitability as OCR paper cannot be determined only by the PCS value. Changes in print density, discontinuity of print, blur of print, and the like due to writing pressure tend to occur more frequently in the case of copying a large number of sheets.

The inventors of the present invention have conducted intensive studies on the improvement of these difficulties, and as a result, as described above, using a color former having a specific structure as a color former, a microcapsule containing the color former is included. Pressure-sensitive copying paper with excellent reproducibility and excellent OCR suitability by using a synthetic polymer material as the wall film material, defining its particle size and film thickness, and combining it with a specific developer. Have been obtained, and the present invention has been completed.

A color image obtained by incorporating a 3,3-bis-aminophenyl-azaphthalide derivative as a color former and a zinc salt of a salicylic acid derivative as a color developer is read out in the visible region of 600 to 700 nm. It shows a high PCS value for its OCR device. By specifying the wall film material of the microcapsules containing the color former as a synthetic polymer material, the generation of color stains is suppressed, and the average particle diameter is further limited to 3 to 15 microns. The present invention eliminates the nonuniformity and discontinuity of the color density due to the pressure difference, and further remarkably suppresses the color stain caused by an unintended pressure. In addition, by specifying the average thickness of the microcapsules to be 0.1 to 0.7 microns, the color fog caused by environmental factors such as heat and humidity is further improved, and as a result, sharp and clear printing can be formed. Thus, a pressure-sensitive copy paper for an OCR device having stable quality characteristics is obtained by completely preventing erroneous reading by the OCR device.

Incidentally, when a natural material is used as the wall film material of the microcapsules, the effect of preventing color stain becomes insufficient. When the average particle diameter of the capsule is less than 3 microns, the color density is lowered and the readability is deteriorated.
The average particle size of the capsule needs to be adjusted in the range of 3 to 15 microns, preferably 5 to 10 microns. Further, when the average film thickness is less than 0.1 micron, unnecessary coloring stains increase, and when the average film thickness exceeds 0.7 micron, the color developing sensitivity decreases.
It is controlled in the range of microns, preferably 0.1-0.4 microns.

The 3,3-bis-aminophenyl-azaphthalide derivative used in the present invention is represented by the following general formula.

[0014]

Embedded image

Wherein R ₁ , R ₂ , R ₃ and R ₄ are each a lower aliphatic alkyl group such as methyl, ethyl and propyl; a lower aliphatic haloalkyl group such as chloromethyl and bromoethyl; a benzyl group; A group (a group that does not provide an aqueous solution as a substituent); a phenyl group; a substituted phenyl group (a group that does not provide an aqueous solution as a substituent);
Each represents a hydrogen atom; a lower aliphatic alkyl group such as methyl, ethyl and propyl; a lower aliphatic alkoxyl group such as methoxy and ethoxy; a halogen atom such as chloro and bromo;
A haloalkyl group such as chloromethyl and trifluoromethyl; an alkylamino group such as methylamino, ethylamino, dimethylamino and diethylamino; a phenoxy group; a nitro group; a lower aliphatic alkylthio group such as methylthio and ethylthio; 2. In the formula, the central carbon atom and the carbonyl carbon atom are bonded to adjacent carbons on the pyridine nucleus. Specific examples of the azaphthalide derivative represented by the above general formula include, for example, 3,3
-Bis- (4'-dimethylaminophenyl) -4-azaphthalide, 3,3-bis- (4'-dimethylaminophenyl) -5-azaphthalide, 3,3-bis- (4'-dimethylaminophenyl)- 6-azaphthalide, 3,3-
Bis- (4'-dimethylaminophenyl) -7-azaphthalide, 3,3-bis- (4'-dimethylamino-2 '
-Methylphenyl) -4-azaphthalide, 3,3-bis- (4'-dimethylamino-2'-methylphenyl)-
5-azaphthalide, 3,3-bis- (4'-dimethylamino-2'-methylphenyl) -6-azaphthalide,
3,3-bis- (4'-dimethylamino-2'-methylphenyl) -7-azaphthalide, 3,3-bis- (4 '
-Dimethylamino-2'-chlorophenyl) -4-azaphthalide, 3,3-bis- (4'-dimethylamino-
2'-chlorophenyl) -6-azaphthalide, 3,3-
Bis- (4'-dimethylamino-2'-chlorophenyl) -7-azaphthalide, 3,3-bis- (4'-dimethylamino-2'-methoxyphenyl) -4-azaphthalide, 3,3-bis- (4'-dimethylamino-2'-
Methoxyphenyl) -5-azaphthalide, 3,3-bis- (4'-dimethylamino-2'-methoxyphenyl)
-6-azaphthalide, 3,3-bis- (4'-dimethylamino-2'-methoxyphenyl) -7-azaphthalide, 3,3-bis- (4'-dimethylamino-2'-methylthiophenyl) -4 -Azaphthalide, 3,3-bis- (4'-dimethylamino-2'-methylthiophenyl) -5-azaphthalide, 3,3-bis- (4'-dimethylamino-2'-methylthiophenyl) -6-azaphthalide , 3,3-bis- (4'-dimethylamino-2 '
-Methylthiophenyl) -7-azaphthalide, 3,3-
Bis- (4'-dimethylamino-2'-chloromethylphenyl) -4-azaphthalide, 3,3-bis- (4'-
Dimethylamino-2'-chloromethylphenyl) -5
Azaphthalide,

3,3-bis- (4'-dimethylamino-
2'-chloromethylphenyl) -6-azaphthalide,
3,3-bis- (4'-dimethylamino-2'-chloromethylphenyl) -7-azaphthalide, 3,3-bis-
(4'-dimethylamino-2'-diethylaminophenyl) -4-azaphthalide, 3,3-bis- (4'-dimethylamino-2'-diethylaminophenyl) -5-azaphthalide, 3,3-bis- (4 '-Dimethylamino-
2'-diethylaminophenyl) -6-azaphthalide,
3,3-bis- (4'-dimethylamino-2'-diethylaminophenyl) -7-azaphthalide, 3,3-bis- (4'-diethylaminophenyl) -4-azaphthalide, 3,3-bis- (4 '-Diethylaminophenyl)
-5-azaphthalide, 3,3-bis- (4'-diethylaminophenyl) -6-azaphthalide, 3,3-bis-
(4'-diethylamino-2'-methylphenyl) -4
-Azaphthalide, 3,3-bis- (4'-diethylamino-2'-methylphenyl) -5-azaphthalide, 3,
3-bis- (4'-diethylamino-2'-methylphenyl) -7-azaphthalide, 3,3-bis- (4'-diethylamino-2'-chlorophenyl) -4-azaphthalide, 3,3-bis- (4'-diethylamino-2'-
Chlorophenyl) -5-azaphthalide, 3,3-bis-
(4'-diethylamino-2'-chlorophenyl) -6
-Azaphthalide, 3,3-bis- (4'-diethylamino-2'-chlorophenyl) -7-azaphthalide, 3,
3-bis- (4'-diethylamino-2'-methoxyphenyl) -4-azaphthalide,

3,3-bis- (4'-diethylamino-
2'-ethoxyphenyl) -4-azaphthalide, 3,3
-Bis- (4'-diethylamino-2'-methoxyphenyl) -5-azaphthalide, 3,3-bis- (4'-diethylamino-2'-methoxyphenyl) -6-azaphthalide, 3,3-bis- ( 4'-diethylamino-2 '
-Methoxyphenyl) -7-azaphthalide, 3,3-bis- (4'-diethylamino-2'-methylthiophenyl) -4-azaphthalide, 3,3-bis- (4'-diethylamino-2'-methylthiophenyl) -5-azaphthalide, 3,3-bis- (4'-diethylamino-2 '
-Methylthiophenyl) -6-azaphthalide, 3,3-
Bis- (4'-diethylamino-2'-methylthiophenyl) -7-azaphthalide, 3,3-bis- (4'-diethylamino-2'-chloromethylphenyl) -4-azaphthalide, 3,3-bis- ( 4'-diethylamino-
2'-chloromethylphenyl) -5-azaphthalide,
3,3-bis- (4'-diethylamino-2'-chloromethylphenyl) -6-azaphthalide, 3,3-bis-
(4'-diethylamino-2'-chloromethylphenyl) -7-azaphthalide,

3,3-bis- (4'-diethylamino-
2'-dimethylaminophenyl) -4-azaphthalide,
3,3-bis- (4'-diethylamino-2'-dimethylaminophenyl) -5-azaphthalide, 3,3-bis- (4'-diethylamino-2'-dimethylaminophenyl) -6-azaphthalide, 3-bis- (4'-diethylamino-2'-dimethylaminophenyl) -7-
Azaphthalide, 3- (4'-diethylaminophenyl)
-3- (4'-dimethylaminophenyl) -4-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dimethylaminophenyl) -5-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dimethylaminophenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dimethylaminophenyl) -7-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dipropylaminophenyl) -4-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dipropylaminophenyl) -5-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dipropylaminophenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dipropylaminophenyl) -7-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-diethylamino-2'-chlorophenyl) -4
-Azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-diethylamino-2'-chlorophenyl) -5-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-diethylamino- 2'-chlorophenyl) -6-azaphthalide,

3- (4'-diethylaminophenyl)-
3- (4'-diethylamino-2'-chlorophenyl)
-7-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-diethylamino-2'-methylphenyl) -4-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'- Diethylamino-2'-
Methylphenyl) -5-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-diethylamino-2'-methylphenyl) -7-azaphthalide, 3-
(4'-diethylaminophenyl) -3- (4'-diethylamino-2'-methoxyphenyl) -4-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-diethylamino-2'-methoxyphenyl)-
5-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-diethylamino-2'-methoxyphenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-diethylamino -2'-
Methoxyphenyl) -7-azaphthalide, 3- (4'-
Diethylaminophenyl) -3- (4′-diethylamino-2′-methylthiophenyl) -4-azaphthalide;
3- (4'-diethylaminophenyl) -3- (4'-
Diethylamino-2'-methylthiophenyl) -5-azaphthalide, 3- (4'-diethylaminophenyl)-
3- (4'-diethylamino-2'-methylthiophenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-diethylamino-2'-methylthiophenyl) -7-azaphthalide, (4'-diethylaminophenyl) -3- (4'-diethylamino-2-etrophenyl) -4-azaphthalide,

3- (4'-diethylaminophenyl)-
3- (4'-diethylamino-2'-nitrophenyl)
-5-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-diethylamino-2'-nitrophenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'- Diethylamino-2'-
Nitrophenyl) -7-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-chlorophenyl) -4-azaphthalide, 3-
(4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-chlorophenyl) -5-azaphthalide, 3- (4'-dimethylaminophenyl) -3-
(4'-diethylamino-2'-chlorophenyl) -6
-Azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-chlorophenyl) -7-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'- Diethylamino-2'-methylphenyl) -4-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-diethylamino-
2'-methylphenyl) -5-azaphthalide, 3-
(4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-methylphenyl) -6-azaphthalide,

3- (4'-dimethylaminophenyl)-
3- (4'-diethylamino-2'-methoxyphenyl) -4-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-methoxyphenyl) -5-azaphthalide, -(4'-dimethylaminophenyl) -3- (4'-diethylamino-
2'-methoxyphenyl) -6-azaphthalide, 3-
(4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-methoxyphenyl) -7-azaphthalide, 3- (4'-dimethylaminophenyl) -3-
(4'-diethylamino-2'-methylthiophenyl-
4-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-methylthiophenyl-5-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'- Diethylamino-2'-
Methylthiophenyl-6-azaphthalide, 3- (4'-
Dimethylaminophenyl) -3- (4'-diethylamino-2'-methylthiophenyl-7-azaphthalide, 3
-(4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-nitrophenyl) -4-azaphthalide, 3- (4'-dimethylaminophenyl) -3-
(4'-diethylamino-2'-nitrophenyl) -5
-Azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-nitrophenyl) -6-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'- Diethylamino-2'-nitrophenyl) -7-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-diethylamino-
2'-phenoxyphenyl) -4-azaphthalide, 3-
(4'-dimethylaminophenyl) -3- (4'-diethylamino-2'-phenoxyphenyl) -5-azaphthalide, 3- (4'-dimethylaminophenyl) -3-
(4'-diethylamino-2'-phenoxyphenyl)
-6-azaphthalide,

3- (4'-dimethylaminophenyl)-
3- (4'-diethylamino-2'-phenoxyphenyl) -7-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-dimethylamino-2'-chlorophenyl) -4-azaphthalide , 3- (4'-dimethylaminophenyl) -3- (4'-dimethylamino-
2'-chlorophenyl) -5-azaphthalide, 3-
(4'-dimethylaminophenyl) -3- (4'-dimethylamino-2'-chlorophenyl) -6-azaphthalide, 3- (4'-dimethylaminophenyl) -3-
(4'-dimethylamino-2'-chlorophenyl) -7
-Azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-dimethylamino-2'-methylphenyl) -4-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4 '-Dimethylamino-2'-methylphenyl) -5-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-dimethylamino-
2'-methylphenyl) -6-azaphthalide, 3-
(4'-dimethylaminophenyl) -3- (4'-dimethylamino-2'-methylphenyl) -7-azaphthalide, 3- (4'-dimethylaminophenyl) -3-
(4'-dimethylamino-2'-methoxyphenyl)-
4-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-dimethylamino-2'-methoxyphenyl) -6-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4 '-Dimethylamino-2'-
Methoxyphenyl) -7-azaphthalide, 3- (4'-
Dimethylaminophenyl) -3- (4'-dimethylamino-2'-methylthiophenyl) -4-azaphthalide;
3- (4'-dimethylaminophenyl) -3- (4'-
Dimethylamino-2'-methylthiophenyl) -5-azaphthalide, 3- (4'-dimethylaminophenyl)-
3- (4'-dimethylamino-2'-methylthiophenyl) -6-azaphthalide,

3- (4'-dimethylaminophenyl)-
3- (4'-dimethylamino-2'-methylthiophenyl) -7-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-dimethylamino-2'-nitrophenyl) -4-azaphthalide , 3- (4'-dimethylaminophenyl) -3- (4'-dimethylamino-
2'-nitrophenyl) -5-azaphthalide, 3-
(4'-dimethylaminophenyl) -3- (4'-dimethylamino-2'-nitrophenyl) -7-azaphthalide, 3- (4'-dimethylaminophenyl) -3-
(4'-dimethylamino-2'-phenoxyphenyl)
-4-azaphthalide, 3- (4'-dimethylaminophenyl) -3- (4'-dimethylamino-2'-phenoxyphenyl) -5-azaphthalide, 3- (4'-dimethylaminophenyl) -3- ( 4'-dimethylamino-
2'-phenoxyphenyl) -6-azaphthalide, 3-
(4'-dimethylaminophenyl) -3- (4'-dimethylamino-2'-phenoxyphenyl) -7-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dimethylamino-2'-methylphenyl) -4
-Azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-methylphenyl) -5-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethyl Amino-2'-methylphenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-
2'-methylphenyl) -7-azaphthalide, 3-
(4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-chlorophenyl) -4-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dimethylamino-2'-chlorophenyl) -5
-Azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-chlorophenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethyl Amino-2'-chlorophenyl) -7-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-
2'-methoxyphenyl) -4-azaphthalide,

3- (4'-diethylaminophenyl)-
3- (4'-dimethylamino-2'-methoxyphenyl) -5-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-methoxyphenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-
2'-methoxyphenyl) -7-azaphthalide, 3-
(4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-methylthiophenyl) -4-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dimethylamino-2'-methylthiophenyl)
-5-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-methylthiophenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4 ' -Dimethylamino-
2'-methylthiophenyl) -7-azaphthalide, 3-
(4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-nitrophenyl) -4-azaphthalide, 3- (4'-diethylaminophenyl) -3-
(4'-dimethylamino-2'-nitrophenyl) -5
-Azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-nitrophenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethyl Amino-2'-nitrophenyl) -7-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-
2'-phenoxyphenyl) -4-azaphthalide, 3-
(4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-phenoxyphenyl) -5-azaphthalide,

3- (4'-diethylaminophenyl)-
3- (4'-dimethylamino-2'-phenoxyphenyl) -6-azaphthalide, 3- (4'-diethylaminophenyl) -3- (4'-dimethylamino-2'-phenoxyphenyl) -7-azaphthalide, 3- (4'-dimethylaminophenyl) -3- {4 '-(N-methyl-
N-phenyl) aminophenyl {-4 or 5-azaphthalide, 3- (4'-dimethylaminophenyl) -3-
{4 '-(N-methyl-N-phenyl) aminophenyl} -6-azaphthalide, 3- (4'-dimethylaminophenyl) -3- {4'-(N-methyl-N-phenyl) aminophenyl} -7-azaphthalide, 3- (4 '
-Diethylamino-2'-ethoxyphenyl) -3-
{4 ′-(N-ethyl-N-phenyl) amino-2′-
Ethoxyphenyl {-4-azaphthalide, 3,3-bis- {4 '-(N-methyl-NP-tolyl) aminophenyl} -4-azaphthalide, 3,3-bis {4'-(N
-Methyl-NP-tolyl) aminophenyl} -5-azaphthalide, 3,3-bis {4 '-(N-methyl-N-
P-tolyl) aminophenyl} -6-azaphthalide,
3,3-bis {4 '-(N-methyl-NP-tolyl)
Aminophenyl -7-azaphthalide and the like.

Among the various azaphthalide derivatives described above, R _{1 to} R ₄ are each a methyl group; an ethyl group; a benzyl group; a substituted benzyl group (substituted) A methyl group, a halogen atom, a methoxy group, or an ethoxy group as a group); a phenyl group; or a substituted phenyl group (having a methyl group, a halogen atom, a methoxy group, or an ethoxy group as a substituent); Compounds that are a methyl group, a methoxy group, or an ethoxy group are particularly preferably used because they are excellent in the desired effects of the present invention. And among the azaphthalide derivatives having such a substituent, particularly-
4-Azaphthalide compounds are most preferably used.

The azaphthalide derivative as described above used in the present invention may be used in combination with a conventional basic coloring agent such as triarylmethanelactones, spiropyrans, fluorans, diphenylmethanes and azines, if necessary. Synthetic oils such as naphthalene fluoride, alkylated diphenyl, alkylated diphenylmethane, alkylated terphenyl,
It is dissolved in an appropriate solvent consisting of vegetable oils such as cotton oil and castor oil, animal oils, mineral oils, and mixtures thereof, and is subjected to a capsule production method such as an interfacial polymerization method or an in-situ method to form a synthetic polymer wall. It is encapsulated in microcapsules with a membrane material. Then, by appropriately adjusting the encapsulation conditions at that time, the capsule is prepared as a capsule having the above-mentioned specific average particle diameter and average film thickness.

The capsule containing the specific coloring agent thus prepared and having a specific average particle diameter and a specific film thickness can be protected by a conventional method using a protective material such as starch granules or cellulose powder.
Latex, a water-soluble binder and the like are appropriately blended to prepare a capsule coating liquid, which is used for the production of upper paper and middle paper.

In the pressure-sensitive copying paper of the present invention, in particular, a salicylic acid derivative zinc salt is selectively used as a color developer. Specific examples of such a color developer include, for example, salicylic acid, 3-isopropylsalicylic acid, 3-phenylsalicylic acid, 3-cyclohexylsalicylic acid, 3-methyl-5
-(Α-methylbenzyl) salicylic acid, 3-methyl-5
-(Α, α-dimethylbenzyl) salicylic acid, 3,5-
Di-sec-butylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3,5-di-tert-butyl-6-methylsalicylic acid, 3-tert-butyl-5-phenylsalicylic acid, 3,5-di- tert-amylsalicylic acid, 3,5-dicyclohexylsalicylic acid, 3-cyclohexyl-5-
(Α-methylbenzyl) salicylic acid, 3-dodecylsalicylic acid, 3-methyl-5-dodecylsalicylic acid, 3-dodecyl-5-methylsalicylic acid, 3-dodecyl-6-methylsalicylic acid, 3-phenyl-5- (α-methyl Benzyl) salicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, 3- (α-methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5-methylsalicylic acid, 3- (α-methyl Benzyl) -5-phenylsalicylic acid, 3 (α, 4-dimethylbenzyl)-
5-methylsalicylic acid, 3,5-di (α, 4-dimethylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -5-methylsalicylic acid, 3- (α, α-dimethylbenzyl) -6-methyl Salicylic acid, 3,5-di (α,
α-dimethylbenzyl) salicylic acid, 3,5-di (α-
Methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5- (α, α-dimethylbenzyl) salicylic acid,
3- (α-methylbenzyl) -5-bromosalicylic acid,
3- (α-methylbenzyl) -4-methylsalicylic acid,
3- (α-methylbenzyl) -6-methylsalicylic acid,
3-nonylsalicylic acid, 3-nonyl-5-methylsalicylic acid, 3-nonyl-6-methylsalicylic acid, 3-nonyl-5-phenylsalicylic acid, 3-methyl-5-nonylsalicylic acid, 5- (4-mesitylmethylbenzyl) ) Zinc salts such as salicylic acid, pinenated salicylic acid, and benzylated styrenated salicylic acid.

The developer coating solution is prepared by adding the above-mentioned zinc salt of the salicylic acid derivative to calcium carbonate, magnesium carbonate, kaolin, aluminum hydroxide, titanium oxide, if necessary.
It is prepared by a method of dispersing in water together with an inorganic pigment such as zinc oxide and activated clay, a binder and the like. Examples of the binders include starches, celluloses, proteins, gum arabic, polyvinyl alcohol, and styrene.
A maleic anhydride copolymer salt, a vinyl acetate-maleic anhydride copolymer salt, a polyacrylate, a styrene-butadiene copolymer emulsion or the like is appropriately selected and used.

The method of applying the coating liquid is not particularly limited. For example, an on-machine or off-machine coater equipped with an appropriate coating device such as an air knife coater, a roll coater, a blade coater, a rod coater, a curtain coater, etc. Is applied to the support and dried so as to be about ² to 10 g / m ² .

For the pressure-sensitive copying paper, for example, US Pat. Nos. 2,505,470, 2,505,471, and 2,505,489
No. 2,548,366, 2,712,507, 2,730,456
Nos. 2,730,457, 3,418,250, 3,924,027
No. 4,010,038, etc., there are various forms, and the present invention can be applied to these various forms of pressure-sensitive copying paper.

[0033]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted to such specific Examples. Parts and% in Examples are parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 [Preparation of developer dispersion] 100 g of zinc 3,5-di (α-methylbenzyl) salicylate was added to 100 g of toluene at 70 g.
The mixture was dissolved at a temperature of ° C to prepare a toluene solution. Separately, 6 g of polyvinyl alcohol having a polymerization degree of 1700 and a saponification degree of 98%
Was placed in a stainless steel beaker having an internal volume of 1000 cc, and the above toluene solution was added thereto while stirring the TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 3000 rpm.

When the addition of the toluene solution was completed, the number of revolutions was increased to 10,000 times per minute, and the mixture was stirred for 2 minutes, and then the dispersion was stirred for 1000 minutes with a stirrer, a thermometer, and a distillation port.
Transferred to a cc hard glass three-necked flask. The flask was heated while slowly rotating the stirrer so that toluene and water were distilled from the distillation port. When this operation was continued at 100 ° C. for about 1 hour, the dispersion was almost free of toluene. This was cooled to obtain an aqueous dispersion containing about 33% of a developer. The average particle diameter of the obtained developer-dispersed particles was 1.
0 microns.

Next, this aqueous dispersion was applied to a sand grinder (MODEL NO, OSG-8G, manufactured by Igarashi Kikai Co., Ltd.) at a rate of 2 minutes per minute.
The mixture was treated under the condition of Kg to prepare a developer dispersion having an average particle size of 0.97 μm.

[Preparation of a developer coating solution] 15 parts of the 33% developer dispersion liquid obtained by the above treatment, 70 parts of calcium carbonate
Parts, 10 parts of zinc oxide and 100 parts of water are mixed and dispersed, and 100 parts of a 10% aqueous solution of polyvinyl alcohol and 20 parts of 50% carboxy-modified SBR latex (trade name: SN-307, manufactured by Sumitomo Nogatack Co., Ltd.) are used as binders. And 200 parts of water were mixed and dispersed to prepare a developer coating solution.

[Production of lower paper] 40 g of the above developer coating solution
/ M ² base paper was coated and dried with an air knife coater so that the dry weight was 6 g / m ^2, and further calendered to prepare a lower sheet for pressure-sensitive copying paper.

[Preparation of Microcapsule Dispersion] In a stirring and mixing vessel equipped with a heating device, 150 parts of a 3% aqueous solution of polyvinyl alcohol (trade name: PVA-117, manufactured by Kuraray Co., Ltd.) was added, and an aqueous medium for preparing capsules was added. And Separately, 3,3-bis- (4-diethylamino-2-ethoxyphenyl)-is used as a color former in 100 parts of alkyldiphenylethane.
8 parts of 4-azaphthalide is dissolved, and polymethylene polyphenyl isocyanate (trade name: Millionate MR400,
A solution obtained by dissolving 5 parts of Nippon Polyurethane Industry Co., Ltd. and 2 parts of 2-isocyanatoethyl-2,6-diisocyanatohexanoate (trade name: T-100, manufactured by Toray Industries, Inc.) is used as a capsule core material. As the above TK in the aqueous medium for capsule preparation
The mixture was emulsified and dispersed at 10,000 rpm for 1 minute using a homomixer.

The emulsified dispersion was added with diethylenetriamine 1
And stirred at room temperature for 30 minutes.
The temperature was raised to 0 ° C., and the reaction was carried out for 3 hours while continuing stirring.
Lower the temperature to room temperature, the average particle size is 5.3 microns,
Polyurea resin with an average wall thickness of 0.19 microns /
A polyurethane resin membrane capsule was prepared.

[Preparation of Microcapsule Coating Solution] To 100 parts (solid content) of the above microcapsule dispersion, 80 parts of wheat starch and 15 parts (solid content) of carboxy-modified SBR latex are added to give a solid content concentration of 20%. To prepare a microcapsule coating solution.

[Manufacture of middle paper] The above-mentioned microcapsule coating liquid is applied to the opposite side of the lower paper by an air knife coater so as to have a dry weight of 4 g / m ² and dried to prepare middle paper for pressure-sensitive copying paper. did.

Example 2 3- (4-Diethylamino-2-ethoxyphenyl) -3- [4- (N-ethyl-N-phenyl) as a color former
Polyurea resin / polyurethane resin wall capsules having the same average particle diameter and thickness were prepared in the same manner as in Example 1 except that [amino-2-ethoxyphenyl] -4-azaphthalide was used. In the same manner as described above, a medium for pressure-sensitive copying paper was prepared.

Example 3 As a color former, 3,3-bis- (4-diethylamino-2) was used.
-Ethoxyphenyl) -4-azaphthalide 4 parts and 3-
(N-ethyl-N-isoamyl) amino-6-methyl-
Example 1 except that 4 parts of 7-anilinofluoran were used.
In the same manner as in Example 1, a polyurea resin / polyurethane resin wall membrane capsule having an average particle diameter of 5.1 μm and an average wall thickness of 0.18 μm was prepared. Created medium paper.

Example 4 A medium for pressure-sensitive copying paper was prepared in the same manner as in Example 3 except that zinc 3-dodecylsalicylate was used as a color developer.

Example 5 In the microcapsule preparation step, the emulsification time between the capsule core substance and the aqueous medium for preparing the capsule was from 1 minute to 30 minutes.
A polyurea resin / polyurethane resin wall membrane capsule having an average particle diameter of 11.8 μm and an average wall thickness of 0.26 μm was prepared in the same manner as in Example 3 except that the time was changed to seconds. In the same manner as in Example 3, a medium for pressure-sensitive copying paper was prepared.

Example 6 The procedure of Example 3 was repeated except that the amount of polymethylene polyphenylisocyanate was reduced from 5 parts to 3 parts during preparation of the microcapsule dispersion liquid. A polyurea resin / polyurethane resin wall film capsule having an average film thickness of 0.12 μm was prepared, and a medium for pressure-sensitive copying paper was prepared in the same manner as in Example 3 below.

Example 7 100 parts of a 5% aqueous solution of α-methylstyrene-maleic anhydride copolymer was added to a stirring and mixing vessel equipped with a heating device, and the pH of the system was adjusted to 4.5 to produce capsules. Aqueous medium. Separately, 3,3-bis- (4-diethylamino-2) was added to 100 parts of alkyldiphenylethane as a coloring agent.
-Ethoxyphenyl) -4-azaphthalide 4 parts and 3-
(N-ethyl-N-isoamyl) amino-6-methyl-
4 parts of 7-anilinofluorane was dissolved, and this was used as a capsule core material and emulsified and dispersed in the above aqueous medium for producing capsules at 10,000 rpm for 1 minute using a TK homomixer.

To this emulsified dispersion was added 50 parts of a 30% aqueous solution of a commercially available melamine-formaldehyde precondensate,
After reacting at 0 ° C. for 2 hours while stirring, the temperature was lowered to room temperature, and a melamine-formaldehyde resin wall capsule having an average particle diameter of 6.0 μm and an average wall thickness of 0.18 μm was obtained. Prepared. A medium sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 3 except that this capsule dispersion liquid was used.

Comparative Example 1 100 parts of activated clay were dispersed in 200 parts of water as a developer, and 50% of carboxy-modified SBR latex 30 was further dispersed.
Part of the coating solution was applied to one side of a 40 g / m ² base paper with an air knife coater so that the dry weight was 6 g / m ^2, and then dried by calendering. Created. Except for using the lower sheet, a medium for pressure-sensitive copying paper was prepared in the same manner as in Example 3.

Comparative Example 2 The average particle size was the same as in Example 1 except that 8 parts of 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluoran was used as a color former. A polyurea resin / polyurethane resin wall membrane capsule having a diameter of 5.5 μm and an average thickness of the wall film of 0.20 μm was prepared, and a medium for pressure-sensitive copying paper was prepared in the same manner as in Example 1. .

Comparative Example 3 In the microcapsule preparation step, the emulsification time between the capsule core material and the aqueous medium for preparing the capsule was from 1 minute to 15 minutes.
A polyurea resin / polyurethane resin wall membrane capsule having an average particle diameter of 16.2 μm and an average wall thickness of 0.41 μm was prepared in the same manner as in Example 3 except that the time was changed to seconds. In the same manner as in Example 3, a medium for pressure-sensitive copying paper was prepared.

Comparative Example 4 The procedure of Example 3 was repeated, except that the polymethylene polyphenyl isocyanate was reduced from 5 parts to 1 part when preparing the microcapsule dispersion, and the average particle size was 4.8 μm. A polyurea resin / polyurethane resin wall film capsule having an average film thickness of 0.07 μm was prepared, and a medium for pressure-sensitive copying paper was prepared in the same manner as in Example 3 below.

COMPARATIVE EXAMPLE 5 100 parts of alkyldiphenylethane was added with 3
4 parts of 3-bis- (4-diethylamino-2-ethoxyphenyl) -4-azaphthalide and 3- (N-ethyl-N-
4 parts of (isoamyl) amino-6-methyl-7-anilinofluoran were dissolved. Separately, isoelectric point 8 as encapsulating agent
25 parts of pigskin gelatin and 25 parts of arabia gum
Dissolved in 00 parts of 50 ° C warm water. The color former-containing oil was added to the gelatin-arabian rubber mixed solution while stirring, and emulsified and dispersed.

The emulsion was further diluted with 1000 parts of warm water, and acetic acid was gradually added dropwise to adjust the pH of the solution to 4 to 4.3. Capsules were produced. After the capsule was cooled and gelled to about 10 ° C., 10 parts of a 25% aqueous solution of glutaraldehyde was added to cure the capsule, and the capsule had an average particle size of 6.1 μm and an average thickness of the wall film of 0.1 μm. A 38-micron gelatin-wall capsule was prepared, and a medium for pressure-sensitive copying paper was prepared in the same manner as in Example 3.

[Measurement of Capsule Particle Size] The average particle size of the capsules prepared in Examples and Comparative Examples was measured with a particle size measuring device (Coulter counter, manufactured by Nikkaki Co., Ltd.), and the results are shown in the table.

[Measurement of Capsule Film Thickness] The average film thickness of the capsules prepared in Examples and Comparative Examples was measured with a tomographic electron micrograph (T-300, manufactured by JEOL Ltd.) of a medium for pressure-sensitive copying paper. The results are shown in the table.

[Quality Comparison Test] OCR Readability A slip was prepared by setting each of the four sheets of medium for pressure-sensitive copying paper prepared in Examples and Comparative Examples as a set, and after printing with a dot printer, the fourth color image was converted into an OCR device (V-3050, Toshiba)
At a reading wavelength of 660 nm. 1000
The slips in the set were read, and the percentage of those that could be read correctly was listed in the table in%.

[0059] Color fog test A slip was prepared by setting each of the four sheets of medium for pressure-sensitive copying paper prepared in Examples and Comparative Examples as a set, and 1000 sets of the slips were allowed to stand at 50 ° C. for 7 days. Printing was performed, and an OCR readability test was performed in the same manner as described above. The results are shown in the table.

[0060] Contact dirt resistance test After overlapping the capsule-coated surface and the developer-coated surface of the medium paper for pressure-sensitive copying paper prepared in Examples and Comparative Examples, and applying a load of 20 kg / cm ² for 1 minute, The degree of color stain on the developer application surface is visually determined according to the following evaluation criteria,
The results are shown in the table. (Evaluation criteria) ：: Almost no contamination. ×: Extremely dirty.

[0061] Rubbing and Staining Test Laminating the capsule-coated surface of the pressure-sensitive copying paper prepared in Examples and Comparative Examples so that the capsule-coated surface and the developer-coated surface face each other, and applying a load of 4 kg / cm ² five times. After the rubbing, the degree of color stain on the developer-applied surface was visually determined according to the following evaluation criteria, and the results are shown in the table. (Evaluation criteria)
：: Almost no contamination. ×: Extremely dirty.

[0062]

[Table 1]

[0063]

As is clear from the results shown in the table, the pressure-sensitive copying papers obtained in the examples of the present invention are all 600-70.
It was an excellent pressure-sensitive copying paper having excellent readability for an OCR device having a reading wavelength in the visible region of 0 nm, and having little change in color density and color fog.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-212882 (JP, A) JP-A-60-240490 (JP, A) JP-A-62-105686 (JP, A) JP-A 61-210 148093 (JP, A) JP-A-63-154389 (JP, A) JP-B-49-17489 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/165 B41M 5 / 155 CA (STN)

Claims (1)

(57) [Claims] 1. A pressure-sensitive copying paper utilizing a color-forming reaction between an electron-donating color-forming agent and an electron-accepting color developing agent, wherein a 3,3-bis-aminophenyl-azaphthalide derivative is used as the electron-donating color-forming agent. Containing a color former in a synthetic polymer microcapsule, having an average particle size of 3 to 15 microns, an average film thickness of 0.1 to 0.7 microns, and an electron accepting property. A pressure-sensitive copying paper comprising a zinc salt of a salicylic acid derivative as a color developer.