JPH04251785A - pressure sensitive copy paper - Google Patents

Abstract

PURPOSE:To provide pressure sensitive copying paper having excellent reading aptitude for an OCR device having reading wave-length in visible region of 600-700nm and without stain to be caused by change of coloring density and coloring fog. CONSTITUTION:3,3-bis-aminophenyl-azaphthalide derivative is contained as a coupler of pressure sensitive copying paper, the coupler is put into a synthetic high polymer micro capsule, its average particle diameter is adjusted to 3-15 micron and average film thickness is adjusted to 0.1-0.7 micron, and salicylic acid derivative zinc salt is used as a coloring material for attaining the above- mentioned end.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to pressure-sensitive copying paper that utilizes a color-forming reaction between an electron-donating color former and an electron-accepting color developer, and is particularly suitable for use in optical character reading (OCR) devices. This paper relates to pressure-sensitive copying paper that exhibits excellent characteristics.

0002

[Prior Art] Pressure-sensitive copying paper (so-called carbonless paper) is
Electron-donating color formers (hereinafter referred to as "color formers") such as crystal violet lactone and benzoyl leucomethylene blue; and electron-accepting color developers (hereinafter referred to as "color formers") such as activated clay, bentonite, phenolic resins, and polyvalent metal salts of aromatic carboxylic acids. This is a copying paper that utilizes the color reaction of a color developer (color developer).
The top paper is made by coating the back side of the base paper with color former-containing microcapsules made by a phase separation method, interfacial polymerization method, in-situ method, etc., and the bottom paper is made by applying a color developer to the surface of the base paper. This is a copy paper in which the coated surfaces of the two sheets are stacked one on top of the other, and a colored image is formed on the bottom sheet by writing on the surface of the top sheet or printing under pressure with a typewriter or the like.

[0003] When a large number of copies are desired, an inner paper coated with the color developer on the surface of the base paper and microcapsules coated on the back side is used between the upper paper and the lower paper to make the necessary number of copies. only inserted. Also, so-called self-coloring paper in which the microcapsules and color developer are formed as a laminated or mixed layer on the same surface of a base paper is also well known as a form of pressure-sensitive copying paper. Demand for pressure-sensitive copying paper has increased as its uses have expanded, such as general slips, delivery slips, unified slips, contract documents, etc.
There has been significant growth in a wide range of products, including computer paper.

On the other hand, with the development of the information processing industry, office automation is progressing, and the rationalization of office processing is being promoted. And as a method of rationalization, OCR and O
As MR devices have become more widespread, it has become necessary for general companies to make their main documents such as order receipts, sales slips, shipping slips, purchase slips, and input/output slips suitable for OCR and OMR devices. There is. Moreover, these slips require multiple copies due to the necessity of the office system.

[0005]

[Problems to be Solved by the Invention] Against this background, there is an increasing demand for the development of OCR slips using pressure-sensitive copying paper, but the PCS value in the infrared region of the colored image of pressure-sensitive copying paper is 0.
．． 15 and has a reading wavelength in the infrared region.
Functions as a dropout collar for the R device,
The problem is that it cannot be read. Also 600~700n
Even for an OCR device having a reading wavelength in the visible region of m, there is a problem in that the PCS value is only about 0.4 in the black coloring of pressure-sensitive copying paper, making reading uncertain. Also,
The color density of pressure-sensitive copy paper may change depending on the writing pressure (printing pressure), and color fog may also occur due to undesired pressure or environmental factors such as heat and humidity. Therefore, pressure-sensitive copy paper suitable for OCR devices is The unique properties of these pressure-sensitive copying papers also pose difficulties in development.

[0006] Therefore, as a result of intensive research into improving these difficulties, the present inventors used a coloring agent with a specific structure as a coloring agent and used it as a wall material for microcapsules containing this coloring agent. By using a synthetic polymer material, specifying its particle size and film thickness, and combining it with a specific color developer, it is extremely effective against OCR devices that have a reading wavelength in the visible range of 600 to 700 nm. The present inventors have discovered that it is possible to obtain pressure-sensitive copying paper that exhibits stable reading performance and has little change in color density or color fog, and has completed the present invention.

[0007]

[Means for Solving the Problems] The present invention is a pressure-sensitive copying paper that utilizes a color-forming reaction between an electron-donating color former and an electron-accepting color developer. - Contains a bis-aminophenyl-azaphthalide derivative, (1) the coloring agent is encapsulated in synthetic polymer microcapsules, (2) the average particle size is 3 to 15 microns, and the average film thickness is 0.1 to 15 microns. 0.7 micron, and (2) a pressure-sensitive copying paper characterized in that a zinc salt of a salicylic acid derivative is used as an electron-accepting color developer.

[0008]

[Operation] As an indicator of the degree of OCR reading aptitude,
The aforementioned PCS (Print Contrast Sign
al) value, so this PCS value will be explained first. That is, the PCS value represents the degree of relative density between the colored print and the paper, and is expressed by the following equation. PCS=(Rw-Rp)/Rw Here, Rw indicates the maximum reflectance of a blank portion of paper within the target area, and Rp indicates the maximum reflectance of printing at an arbitrary measurement point (P). And for general OCR paper, P
The higher the CS value, the clearer the character identification and the higher the readability.

However, when pressure-sensitive copy paper is used as OCR paper, even if the PCS value of the colored image (print) is sufficiently high, changes in print density due to pen pressure, discontinuity of print,
If printing becomes blurred, readability will be significantly reduced. Therefore, suitability as OCR paper cannot be determined simply based on the PCS value. Further, changes in print density due to writing pressure, discontinuity of print, blurring of print, etc. tend to occur more easily when multiple copies are made, so special attention is required.

[0010] The inventors of the present invention have conducted intensive research to improve these difficulties, and as a result, as described above, the present inventors have developed a method of using a coloring agent having a specific structure as a coloring agent, and forming microcapsules containing this coloring agent. Pressure-sensitive copying paper with excellent OCR suitability with good reproducibility by using a synthetic polymer material as the wall material, specifying the particle size and film thickness, and combining it with a specific color developer. The present invention has been completed based on the discovery that the following can be obtained.

[0011] A color image obtained by containing a 3,3-bis-aminophenyl-azaphthalide derivative as a color former and combining this with a zinc salt of a salicylic acid derivative as a color developer has a reading wavelength in the visible range of 600 to 700 nm. It shows a high PCS value for OCR devices with By specifying the wall material of the microcapsules containing this coloring agent to be a synthetic polymer material, the occurrence of colored stains is suppressed, and by further limiting the average particle size to 3 to 15 microns, the brush This eliminates non-uniformity and discontinuity in color density due to pressure differences, and more significantly suppresses color stains caused by undesired pressure. In addition, by specifying the average thickness of the microcapsules to 0.1 to 0.7 microns, color fog caused by environmental factors such as heat and humidity can be further improved, resulting in the formation of sharp and clear prints. In this way, a pressure-sensitive copying paper for use in an OCR device is obtained which completely prevents misreading by an OCR device and has stable quality characteristics.

[0012] Incidentally, if a natural material is used as the wall material of the microcapsule, the effect of preventing colored stains will be insufficient. In addition, if the average particle size of the capsule is less than 3 microns, the color density will decrease and readability will deteriorate, and if it exceeds 15 microns, color stains will occur.
The average particle size of the capsules needs to be adjusted within the range of 3 to 15 microns, preferably 5 to 10 microns. Furthermore, if the average film thickness becomes thinner than 0.1 micron, unnecessary colored stains will increase, and if it exceeds 0.7 micron, the color development sensitivity will decrease, so the average film thickness of the capsule should be 0.1 to 0.7
Micron, preferably adjusted in the range of 0.1 to 0.4 micron.

The 3,3-bis-aminophenyl-azaphthalide derivative used in the present invention has the following general formula [Chemical formula 1]
].

[0014]

[Chemical formula 1]

[In the formula, R1, R2, R3, R4
are lower aliphatic alkyl groups such as methyl, ethyl, and propyl; lower aliphatic haloalkyl groups such as chloromethyl and bromoethyl; benzyl group; substituted benzyl group (a group that does not form an aqueous solution as a substituent); phenyl group; substituted phenyl Indicates a group (as a substituent, a group that does not give an aqueous solution),
X and Y are each a hydrogen atom; lower aliphatic alkyl groups such as methyl, ethyl, and propyl; lower aliphatic alkoxyl groups such as methoxy and ethoxy; halogen atoms such as chloro and brome; haloalkyl groups such as chloromethyl and trifluoromethyl ; alkylamino groups such as methylamino, ethylamino, dimethylamino, and diethylamino; phenoxy groups; nitro groups; lower aliphatic alkylthio groups such as methylthio and ethylthio, and n is 1 to 2. In the formula, the central carbon atom and carbonyl carbon atom are bonded to adjacent carbon atoms on the pyridine nucleus. ] Specific examples of azaphthalide derivatives 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'-Chlorphenyl)-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'-chlorphenyl)-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, 3-bis-(4'-diethylamino-2'-dimethylaminophenyl)-7-
Azapthalide, 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'-chlorphenyl)-4-azaphthalide, 3-(4'-diethylaminophenyl)-3-(4'-diethylamino-2
'-Chlorphenyl)-5-azaphthalide, 3-(4'
-diethylaminophenyl)-3-(4'-diethylamino-2'-chlorphenyl)-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-
Azapthalide, 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, 3-(4'-diethylaminophenyl)-3-(4'- diethylamino-2
-etrophenyl)-4-azaphthalide,

[0020]
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
'-Chlorphenyl)-5-azaphthalide, 3-(4'
-dimethylaminophenyl)-3-(4'-diethylamino-2'-chlorphenyl)-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, 3 -(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'-phenocykyphenyl)-4-azaphthalide, 3-(4'-dimethylaminophenyl)-3-(4'-diethylamino-2'-phenocykyphenyl)-5-azaphthalide, 3
-(4'-dimethylaminophenyl)-3-(4'-diethylamino-2'-phenocykyphenyl)-6-azaphthalide,

3-(4'-dimethylaminophenyl)-
3-(4'-diethylamino-2'-phenocykyphenyl)-7-azaphthalide, 3-(4'-dimethylaminophenyl)-3-(4'-dimethylamino-2'-chlorophenyl)-4-azaphthalide , 3-(4'-dimethylaminophenyl)-3-(4'-dimethylamino-2
'-Chlorphenyl)-5-azaphthalide, 3-(4'
-dimethylaminophenyl)-3-(4'-dimethylamino-2'-chlorophenyl)-6-azaphthalide, 3
-(4'-dimethylaminophenyl)-3-(4'-dimethylamino-2'-chlorphenyl)-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'-dimethylamino-2'-methylphenyl)
-6-Azaphthalide, 3-(4'-diethylaminophenyl)-3-(4'-dimethylamino-2'-methylphenyl)-7-azaphthalide, 3-(4'-diethylaminophenyl)-3-(4'-dimethylamino-2'-
Chlorphenyl)-4-azaphthalide, 3-(4'-diethylaminophenyl)-3-(4'-dimethylamino-2'-chlorphenyl)-5-azaphthalide, 3-(
4'-diethylaminophenyl)-3-(4'-dimethylamino-2'-chlorophenyl)-6-azaphthalide, 3-(4'-diethylaminophenyl)-3-(4'
-dimethylamino-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'-dimethylamino-
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-N-P-tolyl)aminophenyl}-
4-Azaphthalide, 3,3-bis{4'-(N-methyl-N-P-tolyl)aminophenyl}-5-azaphthalide, 3,3-bis{4'-(N-methyl-N-P- Examples include tolyl)aminophenyl}-6-azaphthalide, 3,3-bis{4'-(N-methyl-N-P-tolyl)aminophenyl}-7-azaphthalide, and the like.

Among the various azaphthalide derivatives as described above, R1 to R4 are each a methyl group; an ethyl group;
Benzyl group; substituted benzyl group (methyl group as a substituent,
phenyl group; or substituted phenyl group (having a methyl group, halogen atom, methoxy group, or ethoxy group as a substituent), where X and Y are each a methyl group; a methoxy group ; or an ethoxy group is particularly preferably used because it is excellent in the desired effects of the present invention. Among the azaphthalide derivatives having such substituents, -4-azaphthalide compounds are most preferably used.

The above-mentioned azaphthalide derivatives used in the present invention can be used in combination with common basic coloring agents such as triarylmethane lactones, spiropyrans, fluorans, diphenylmethanes, and azines, if necessary, to produce alkyl Synthetic oils such as naphthalene, alkylated diphenyl, alkylated diphenylmethane, alkylated terphenyl, etc.
It is dissolved in a suitable solvent consisting of vegetable oils such as cotton oil and castor oil, animal oils, mineral oils, and mixtures thereof, and is formed into synthetic polymer walls by capsule manufacturing methods such as interfacial polymerization and in-situ methods. It is encapsulated in microcapsules using a membrane material. Then, by appropriately adjusting the encapsulation conditions at that time, capsules having a specific average particle diameter and average film thickness as described above are prepared.

The thus prepared capsules containing a specific coloring agent and having a specific average particle diameter and average film thickness are prepared by adding a protective material such as starch granules, cellulose powder, latex, water-soluble binder, etc. in accordance with a conventional method. It is mixed appropriately to prepare a capsule coating liquid and used for manufacturing top paper and inner paper.

In the pressure-sensitive copying paper of the present invention, salicylic acid derivative zinc salt is selectively used as a color developer, and specific examples of such color developer include 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-ter
t-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-methylbenzyl)salicylic acid, 3-phenyl-5-(α, α-dimethylbenzyl)salicylic acid, 3
-(α-methylbenzyl)salicylic acid, 3-(α-methylbenzyl)-5-methylsalicylic acid, 3-(α-methylbenzyl)-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-methylsalicylic acid, 3,5-di(α,α-dimethylbenzyl)salicylic acid, 3,5-di(α-methylbenzyl) salicylic acid, 3-(α-methyl benzyl)-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-
Examples include zinc salts such as methylsalicylic acid, 3-nonyl-5-phenylsalicylic acid, 3-methyl-5-nonylsalicylic acid, 5-(4-mesitylmethylbenzyl)salicylic acid, pinenated salicylic acid, and benzylated styrenated salicylic acid.

[0030] The color developer coating liquid contains the above-mentioned salicylic acid derivative zinc salt, calcium carbonate, magnesium carbonate, kaolin, aluminum hydroxide, titanium oxide,
It is prepared by dispersing it in water together with inorganic pigments such as zinc oxide and activated clay, binders, etc. Examples of binders include starches, cellulose, proteins, gum arabic, polyvinyl alcohol, and styrene.
Maleic anhydride copolymer salts, vinyl acetate-maleic anhydride copolymer salts, polyacrylates, styrene-butadiene copolymer emulsions, and the like are appropriately selected and used.

The method of applying the coating liquid is not particularly limited, and for example, an on-machine or off-machine coater equipped with an appropriate coating device such as an air knife coater, roll coater, blade coater, rod coater, or curtain coater can be used to It is coated on a support and dried so that it has a weight of about 2 to 10 g/m2.

Regarding pressure-sensitive copying paper, for example, US Pat. No. 2,505,470 and US Pat.
No. 2,505,489, No. 2,548,36
No. 6, No. 2,712,507, No. 2,730,4
No. 56, No. 2,730,457, No. 3,418,
No. 250, No. 3,924,027, No. 4,010
, No. 038, etc., and the present invention can be applied to these various forms of pressure-sensitive copying paper.

[0033]

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is of course not limited to these. Note that parts and % in the examples indicate parts by weight and % by weight, respectively, unless otherwise specified.

Example 1 [Preparation of color developer dispersion] 100 g of 3,5-di(α-methylbenzyl) zinc salicylate was dissolved in 100 g of toluene.
A toluene solution was prepared by mixing and dissolving at 0°C. Separately, polyvinyl alcohol 6 with a degree of polymerization of 1700 and a degree of saponification of 98%
Pour 300 g of water containing T.g into a stainless steel beaker with an internal volume of 1000 cc. K. Homo mixer (
Tokushu Kika Kogyo Co., Ltd.) was stirred at 3000 revolutions per minute, and the toluene solution was added thereto.

After adding the toluene solution, increase the rotation speed to 10,000 rpm and stir for 2 minutes, then pour this dispersion into a vacuum chamber with an internal volume of 1,000 ml equipped with a stirrer, thermometer and distillation port.
The mixture was transferred to a three-necked cc hard glass flask. The flask was heated while rotating the stirrer slowly so that toluene and water were distilled out from the distillation port. After continuing this operation at 100° C. for about 1 hour, the dispersion liquid contained almost no toluene. This was cooled to obtain an aqueous dispersion containing about 33% of the color developer. The average particle diameter of the obtained developer-dispersed particles was 1
．． It was 0 micron.

Next, this aqueous dispersion was passed through a sand grinder (manufactured by Igarashi Kikai Co., Ltd., MODEL NO., OSG-
8G) at 2Kg per minute, and the average particle size was 0.
．． A 97 micron developer dispersion was prepared.

[Preparation of color developer coating liquid] 15 parts of the 33% color developer dispersion obtained in the above treatment, 70 parts of calcium carbonate, 10 parts of zinc oxide, and 100 parts of water were mixed and dispersed, and then a binder was added. as 10% polyvinyl alcohol aqueous solution 1
A developer coating liquid was prepared by mixing and dispersing 20 parts of carboxy-modified SBR latex (trade name: SN-307, manufactured by Sumitomo Naugatac) and 200 parts of water.

[Manufacture of bottom paper] 40g of the above color developer coating liquid
/m2 base paper was coated with an air knife coater and dried to a dry weight of 6 g/m2, and then calendered to prepare a base paper for pressure-sensitive copying paper.

[Preparation of microcapsule dispersion] Polyvinyl alcohol (
Product name: PVA-117, manufactured by Kuraray Co., Ltd.) 3% aqueous solution 1
50 parts were added to form an aqueous medium for capsule preparation. Separately,
3 as a coloring agent to 100 parts of alkyldiphenylethane.
Dissolve 8 parts of 3-bis-(4-diethylamino-2-ethoxyphenyl)-4-azaphthalide, and then add 5 parts of polymethylene polyphenylisocyanate (trade name: Millionate MR400, manufactured by Nippon Polyurethane Kogyo Co., Ltd.) and 2-isocyanate. A solution obtained by dissolving 2 parts of ethyl-2,6-diisocyanatohexanoate (trade name: T-100, manufactured by Toray Industries, Inc.) was used as a capsule core material in the above aqueous medium for capsule preparation. K. 10 per minute using a homomixer
The mixture was emulsified and dispersed at 000 rpm for 1 minute.

Diethylenetriamine 1 is added to this emulsified dispersion.
After stirring at room temperature for 30 minutes, the temperature of the system was lowered to 7.
The temperature was raised to 0° C., and the mixture was reacted for 3 hours while stirring. The average particle size is 5.3 microns when the temperature is lowered to room temperature.
Polyurea resin with an average wall thickness of 0.19 microns/
Polyurethane resin wall capsules were prepared.

[Preparation of microcapsule coating solution] 80 parts of wheat starch and 15 parts of carboxy-modified SBR latex (solid content) were added to 100 parts (solid content) of the above microcapsule dispersion to give a solid content concentration of 20%. A microcapsule coating liquid was prepared as follows.

[Manufacture of inner paper] The above-mentioned microcapsule coating liquid was applied to the opposite side of the lower paper using an air knife coater and dried to produce inner paper for pressure-sensitive copying paper so that the dry weight was 4 g/m2. .

Example 2 3-(4-diethylamino-2-ethoxyphenyl)-3-[4-(N-ethyl-N-phenyl) as a coloring agent
A polyurea resin/polyurethane resin wall capsule having the same average particle diameter and film thickness was prepared in the same manner as in Example 1 except that amino-2-ethoxyphenyl]-4-azaphthalide was used, and the following Example 1 was prepared. In the same manner as above, inner paper for pressure-sensitive copying paper was prepared.

Example 3 3,3-bis-(4-diethylamino-2
-ethoxyphenyl)-4-azaphthalide and 4 parts of 3-(
N-ethyl-N-isoamyl)amino-6-methyl-7
- A polyurea resin/polyurethane resin wall film having an average particle size of 5.1 microns and an average thickness of the wall film of 0.18 microns in the same manner as in Example 1 except that 4 parts of anilinofluorane was used. A capsule was prepared, and an inner sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 1.

Example 4 An inner sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 3, except that zinc 3-dodecylsalicylate was used as the color developer.

Example 5 In the microcapsule preparation process, the emulsification time of the capsule core material and the aqueous medium for capsule preparation was varied from 1 minute to 30 minutes.
Polyurea resin/polyurethane resin wall capsules with an average particle diameter of 11.8 microns and an average wall thickness of 0.26 microns were prepared in the same manner as in Example 3, except that the time was changed to 2 seconds. An inner sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 3.

Example 6 The microcapsule dispersion was prepared in the same manner as in Example 3, except that the amount of polymethylene polyphenylisocyanate was reduced from 5 parts to 3 parts. A polyurea resin/polyurethane resin wall capsule having an average film thickness of 0.12 microns was prepared, and an inner sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 3.

Example 7 Capsule production was carried out by adding 100 parts of a 5% aqueous solution of α-methylstyrene-maleic anhydride copolymer into a stirring mixing vessel equipped with a heating device and adjusting the pH of the system to 4.5. It was used as an aqueous medium. Separately, 3,3-bis-(4-diethylamino-2
-ethoxyphenyl)-4-azaphthalide and 4 parts of 3-(
N-ethyl-N-isoamyl)amino-6-methyl-7
- 4 parts of anilinofluorane was dissolved and used as a capsule core material, and T. K.
Emulsification and dispersion was carried out for 1 minute at 10,000 revolutions per minute using a homomixer.

50 parts of a 30% aqueous solution of a commercially available melamine-formaldehyde initial condensate was added to this emulsified dispersion, and 7
After reacting at 0°C for 2 hours with continuous stirring, the temperature was lowered to room temperature to form melamine-formaldehyde resin wall capsules with an average particle size of 6.0 microns and an average wall thickness of 0.18 microns. Prepared. An inner sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 3 except that this capsule dispersion was used.

Comparative Example 1 A coating solution prepared by dispersing 100 parts of activated clay as a color developer in 200 parts of water and further adding 30 parts of 50% carboxy-modified SBR latex was coated on one side of a 40 g/m2 base paper by dry weight. After coating with an air knife coater and drying to give a weight of 6 g/m 2 , a calendering process was performed to prepare a base sheet for pressure-sensitive copying paper. An inner sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 3 except that this bottom sheet was used.

Comparative Example 2 The average particle A polyurea resin/polyurethane resin wall capsule having a diameter of 5.5 microns and an average wall thickness of 0.20 microns was prepared, and an inner paper for pressure-sensitive copying paper was prepared in the same manner as in Example 1. .

Comparative Example 3 In the microcapsule preparation process, the emulsification time of the capsule core material and the aqueous medium for capsule preparation was varied from 1 minute to 15 minutes.
Polyurea resin/polyurethane resin wall capsules with an average particle diameter of 16.2 microns and an average wall thickness of 0.41 microns were prepared in the same manner as in Example 3, except that the time was changed to 2 seconds. An inner sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 3.

Comparative Example 4 A microcapsule dispersion was prepared in the same manner as in Example 3, except that the amount of polymethylene polyphenylisocyanate was reduced from 5 parts to 1 part, and the average particle size was 4.8 microns. A polyurea resin/polyurethane resin wall capsule having an average film thickness of 0.07 microns was prepared, and an inner sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 3.

Comparative Example 5 To 100 parts of alkyldiphenylethane was added 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-anilinofluorane were dissolved. Separately as an encapsulating agent isoelectric point 8
25 parts of pigskin gelatin and 25 parts of gum arabic.
00 parts of 50°C hot water. The coloring agent-containing oil was added to this gelatin-gum arabic mixed solution while stirring and emulsified and dispersed.

When this emulsion is further diluted with 1,000 parts of warm water and acetic acid is gradually added dropwise to adjust the pH of the liquid to 4 to 4.3, the encapsulant is deposited around the oil droplets and becomes a sol. Formed capsules. After cooling the capsules to about 10° C. and gelling them, 10 parts of a 25% aqueous solution of glutaraldehyde was added to harden the capsules so that the average particle size was 6.1 μm and the average wall thickness was 0.5 μm. A 38 micron gelatin-based wall capsule was prepared, and an inner sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 3.

[Measurement of Capsule Particle Diameter] The average particle diameter of the capsules prepared in the Examples and Comparative Examples was measured using a particle size measuring machine (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 determined using a tomographic electron micrograph of inner paper for pressure-sensitive copying paper (T-300, manufactured by JEOL).
The results are listed in the table.

[Quality comparison test] ■. OCR readability A slip was created using each set of 4 inner sheets for pressure-sensitive copying paper created in the Examples and Comparative Examples, and after printing with a dot printer, the colored image of the 4th sheet was printed using an OCR device (V-3050, (manufactured by Toshiba) at a reading wavelength of 660 nm. 1
000 sets of slips were read, and the percentage of the slips that could be read accurately was recorded in the table.

[0059]■. Color Fog Test A set of 4 sheets each of the pressure-sensitive copy paper inserts prepared in the Examples and Comparative Examples was used to create a set of slips, and after leaving the 1000 sets of slips at 50°C for 7 days, they were printed using a dot printer. It was printed and tested for OCR readability in the same manner as above, and the results are listed in the table.

■. Contact Stain Resistance Test The inner paper for pressure-sensitive copying paper prepared in Examples and Comparative Examples was stacked so that the capsule-coated side and the developer-coated side faced each other, and a load of 20 kg/cm2 was applied for 1 minute. The degree of colored stain on the surface coated with the color developer was visually evaluated using the following evaluation criteria, and the results are listed in the table. (Evaluation criteria) ○: Hardly dirty. ×: Extremely dirty.

■. Scratch Resistance Test The media for pressure-sensitive copying paper prepared in Examples and Comparative Examples were stacked so that the capsule-coated side and the developer-coated side faced each other, and rubbed 5 times under a load of 4 kg/cm2. After combining, the degree of colored stain on the surface coated with the color developer was visually evaluated using the following evaluation criteria, and the results are listed in the table. (Evaluation criteria) ○: Hardly dirty. ×: Extremely dirty.

[0062]

[Table 1]

[0063]

Effects of the Invention As is clear from the results in the table, all of the pressure-sensitive copying papers obtained in the Examples of the present invention had a
It was an excellent pressure-sensitive copying paper that had excellent readability for an OCR device having a reading wavelength in the visible region of 0 nm, and had little change in color density or color fog.

Claims (1)

[Claims] [Claim 1] A pressure-sensitive copying paper that utilizes a color-forming reaction between an electron-donating color former and an electron-accepting color developer, wherein: (1) the electron-donating color former is a 3,3-bis-aminophenyl-azaphthalide derivative; (1) The coloring agent is encapsulated in synthetic polymer microcapsules, (2) The average particle diameter is 3 to 15 microns, and the average film thickness is 0.1 to 0.7 microns. ■Pressure-sensitive copying paper characterized by using salicylic acid derivative zinc salt as an electron-accepting color developer.