JPH08192571A - Carbonless pressure-sensitive copying paper for optical reading - Google Patents

Abstract

(57) [Summary] [Object] To provide a carbon-free pressure-sensitive copying paper for optical reading, which has excellent optical reading performance with a small amount of coloring agent applied. [Structure] The color development reaction between an electron-donating color developing agent and an electron-accepting color developing agent is utilized, and the color-developed image is 600 to 1000 nm.
In the carbonless pressure-sensitive copying paper for optical reading having absorption in the wavelength region of 1, the electron-donating color former-encapsulating microcapsules are provided on the pigment coating layer using the inorganic solid fine particles provided on the support. Preferably, JI of inorganic solid fine particles
Oil absorption by SK5101 is 20-40ml / 100g
And the coating amount of the pigment coating layer is 3.0 to 8.0 g / m ² .

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 sheet utilizing the color-forming reaction between an electron-donating color former and an electron-accepting color developer, and is particularly excellent for optical reading of OCR, bar codes and the like. The present invention relates to a carbonless pressure-sensitive copying paper for optical reading.

[0002]

2. Description of the Related Art Carbon-free pressure-sensitive copying papers are disclosed, for example, in U.S. Pat. Nos. 2,505,470, 2,505,489, 2,548,366, 2,550,471, 2,712,507, 2,730,456 and 2,730,457. As described in JP-A-3418250, JP-A-3418250 and JP-A-3672935, basically, an electron-donating color former (hereinafter referred to as a color former) is dissolved in a high boiling point solvent,
A top paper (referred to as CB) in which a coating layer containing microcapsules and containing the microcapsules is applied to the back surface of a support, and an electron-accepting color developer that reacts with the color former (hereinafter, color developer). When a lower sheet (referred to as CF) coated with a coating layer containing a colorant) on the surface of the support is overlaid and printed with an appropriate pressure, the colorant flows out from the colorant-encapsulating microcapsules of the upper sheet. And transferred to the lower sheet, the developer layer is colored and a copy image is obtained at the same time as printing.

When a large number of copies are desired, the above-mentioned developer-containing layer is coated on the front surface of the support and the color-forming agent-encapsulating microcapsule-containing layer is coated on the back surface. The required number of sheets are inserted in between. Also, a self-coloring paper (self) formed on the same surface of a support by laminating or mixing a color-capsule-containing microcapsule-containing layer and a color-developing agent-containing layer is well known as a form of carbonless pressure-sensitive copying paper. Has been.

Many methods for producing microcapsules containing a color former are known. Typical methods include the following various methods. A coacervation method using a polyion complex of gelatin-arabic gum (US Pat. No. 2800)
No. 457 and No. 2800458). An interfacial polymerization method in which an insoluble film is formed at the interface between a hydrophilic liquid serving as a dispersion medium and a hydrophobic liquid to be included. -Initial condensates such as melamine-formaldehyde resin and urea-formaldehyde resin are added from the side of the hydrophilic liquid serving as a dispersion medium, and then resinified to be encapsulated in
In situ polymerization method (Japanese Patent Publication No. 36-9168, 4)
7-23165, JP-A-48-57892, JP-A-51-9079, JP-A-54-25277, etc.) and the like. Among these, synthetic resin capsules are often used because of the cheap and stable supply of raw materials, the production of high-concentration microcapsule emulsions, and the simple manufacturing process.

The carbonless pressure-sensitive copying paper has the following applications.
For example, general slips, shipping slips, unified slips, contract documents,
It is widely used mainly for computer paper. Office automation is progressing with the development of the information processing industry, and OCR, O
With the introduction of MR devices and bar code readers, information is input and output mechanically, and labor is saved for rationalization. Therefore, even for slips using carbonless pressure-sensitive copying paper, it has become necessary to make the paper usable by optical reading devices such as OCR, OMR devices, and bar code reading devices.

However, a copy image of a general carbon-free pressure-sensitive copying paper which has been conventionally used cannot be read by an optical reading device having a reading wavelength of 600 to 1000 nm. Therefore, the copy image is 60
A color former having absorption in the range of 0 to 1000 nm has been developed and is being applied to this application. Examples of this type of color-forming agent include, for example, JP-B-49-17489 and JP-A-51-
No. 90608, No. 51-121035, No. 51-12
No. 1037, No. 62-243653, No. 62-371.
58, 63-154389, 63-18567.
4, JP-A-2-188291, and JP-A-2-231190.
No. 4, No. 4-173288, No. 4-212882, No. 4-224991, No. 4-251785, No. 4-2.
It is disclosed in various publications such as 72889.

[0007]

It has become possible to obtain a color image having absorption in the wavelength range of 600 to 1000 nm by using such a color forming agent, but it is possible to obtain a color image for optical reading. It is necessary to increase the image density, and for this reason, it has been necessary to use a top paper coated with a large amount of an expensive color former.

As a technique for effectively using a color former in a general carbonless pressure-sensitive copying paper, Japanese Patent Application Laid-Open No. 3-236 is known.
In 990, a proposal has been made in which a coating layer containing solid wax-encapsulated microcapsules is provided on a support, and a color former-encapsulated microcapsule-containing layer is provided thereon. This technique was effective, and it was possible to reduce the coating amount of the color former, but since the solid wax-containing microcapsules themselves were expensive, it was necessary to study a cheaper method for industrialization. .

Further, in order to improve the reading performance of the optical reading device, when the copied image is a line such as a character or a bar code, it is necessary to reduce the distortion and bleeding of the line. When the support is paper, the unevenness due to the entanglement of pulp fibers also affects the microcapsule coating layer, and it is difficult to obtain a sufficiently clear copy image without distortion and bleeding.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, a color image of 600 to 10 is obtained.
A carbon-free pressure-sensitive copying paper for optical reading that can be optically read in the wavelength region of 00 nm, in which a layer mainly composed of inorganic solid fine particles and an adhesive is provided on a support, and a color-forming agent-encapsulating microcapsule is contained on the layer. By providing the layer, it becomes possible to obtain a carbon-free pressure-sensitive copying paper having excellent optical reading performance by using a small amount of the color former.

The inorganic solid fine particles used in the present invention include metal carbonates such as calcium carbonate and magnesium carbonate,
Metal oxides such as zinc oxide, titanium oxide and magnesium oxide, metal hydroxides such as aluminum hydroxide and zinc hydroxide, kaolin, talc, zeolite, clay, calcined kaolin, fine shirasu, physically and chemically active Solid particles such as clay minerals such as activated clay that have been removed are included. In particular, in order to efficiently transfer the color-forming agent-containing oil flowing out from the microcapsules to the color developer-coated sheet, it is preferable to use solid fine particles having a low oil absorption amount as the inorganic solid fine particles applied to the support. It is preferable that the oil absorption by K5101 is 20 to 40 ml / 100 g. Suitable examples include kaolin and aluminum hydroxide.

The coating amount of the inorganic solid fine particle coating layer (pigment layer) provided on the support is preferably 3.0 to 8.0 g / m ² . In order to efficiently transfer the color-forming agent-containing oil to the lower paper, the surface of the support on which the microcapsule layer is coated is covered with a pigment layer as much as possible, and cellulose fibers are not exposed on the surface. Further, it is preferable that pores on the surface of the support, which are generated by the entanglement of the cellulose fibers, are covered with the pigment layer. Therefore, the minimum coating amount of the pigment layer required is 3.0 g / m ² , and the higher the coating amount, the more completely the support can be covered and the more effective transfer of the color former to the lower paper. You can When the coating amount is less than 3.0 g / m ² , the transfer of the color developing agent is better than in the case where no pigment layer is provided, but the effect is insufficient. Further, the pigment layer may be provided in an amount of 8.0 g / m ² or more, but a remarkable effect in the case of 8.0 g / m ² or more cannot be expected.

In the present invention, examples of the color former which produces a color image having an absorption wavelength in the range of 600 to 1000 nm include:
Japanese Patent Publications 58-5940, 58-5940, 49
-17489, 63-51113, 4-5
064, 4-5065, 4-5066, 4
-5068, JP-A-51-90608, 62-2.
43652, 62-257970, 62-28.
8078, 63-102975, 63-371.
58, 63-154389, 63-18567.
4, JP-A-2-188291, and JP-A-2-231190.
No. 4, No. 4-173288, No. 4-212882, No. 4-224991, No. 4-251785, No. 4-2.
The following compounds as described in each publication such as 72889 and 5-32040 are mentioned.

3,3-bis [1,1-bis (4-dimethylaminophenyl) ethylene-2-yl] -4,5,
6,7-Tetrachlorophthalide, 3,3-bis [1,1
-Bis (2-methoxy-4-diethylaminophenyl)
Ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [1,1-bis (4-dimethylaminophenyl) ethylene-2-yl] -5-pyrrolidinophthali 3,3-bis [1,1-bis (4-dimethylaminophenyl) ethylene-2-yl] -5-azaphthalide, 3,3-bis [1,1-bis (4-pyrrolidinophenyl) ethylene -2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [1,1-bis (4
-Pyrrolidinophenyl) ethylene-2-yl] -5-ethoxyphthalide, 3,3-bis [1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl] -5-pyrrolidinophthalide, 3,3-bis [1,1-bis (4-piperidinophenyl) ethylene-2-yl] -4,5,6
7-tetrachlorophthalide,

3,3-bis [1,1-bis (4-morpholinophenyl) ethylene-2-yl] -4,5,6,7
-Tetrachlorophthalide, 3,3-bis [1,1-bis (2-methyl-4-pyrrolidinophenyl) ethylene-2
-Yl] -4,5,6,7-tetrachlorophthalide,
3,3-bis [1,1-bis (jurolidin-5-yl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3- [2- (P-dimethylaminophenyl) -2- (P-methoxyphenyl) ethenyl] 3-
[2- (P-pyrrolidinophenyl) -2- (P-methoxyphenyl) ethenyl] phthalide, 3,3-bis [2-
(P-Dimethylaminophenyl) -2- (P-methoxyphenyl) ethenyl] phthalide, 3,3-bis [2-
(P-Pyrrolidinophenyl) -2- (P-methoxyphenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [2- (P-pyrrolidinophenyl] ) -2- (P-Methylphenyl) ethylene-2
-Yl] -4,5,6,7-tetrachlorophthalide,
3,3-bis [2-P-dimethylaminophenyl) -2
-(P-Methoxyphenyl) ethylene-2-yl]-
4,5,6,7-Tetrachlorophthalide, 3,3-bis [2- (P-dimethylaminophenyl) -2- (P-methylphenyl) ethylene-2-yl] -4,5,6 7
-Tetrachlorophthalide,

3,6,6'-Trisdimethylamino-spiro (fluorene-9,3'-phthalide), 3,6,6
6'-trisdiethylamino-spiro (fluorene-
9,3'-phthalide), 3,6,6'-trisdi-n-
Propylamino-spiro (fluorene-9,3'-phthalide), 3-di-n-butylamino-6-dimethylamino-6'-diethylamino-spiro (fluorene-9,
3'-phthalide), 3,3-bis [2- (4-dimethylaminophenyl) -2- (4-methoxyphenyl) ethyl] 4,5,6,7-tetrachlorophthalide, 3,3-
Bis [2-2-bis (4-dimethylaminophenyl) ethenyl] 4,5,6,7-tetrachlorophthalide, 3,
3-bis [2-2-bis (4-dimethylaminophenyl) ethenyl] 5-pyrrolidinophthalide, 3,3-bis [2-2-bis (4-dimethylaminophenyl) ethenyl] 5-azaphthalide, 3 , 3-Bis [2- (p-methoxyphenyl) -2- (p-pyrrolidinophenyl) ethenyl] 4,5,6,7-tetrachlorophthalide, 3,3
-Bis [2- (p-methoxyphenyl) -2- (p-dimethylaminophenyl) ethenyl] 4,5,6,7-tetrachlorophthalide,

6 '-[{4- (4-anilino) anilino} anilino] -2'-chloro-3'-methylspiro [phthalide-3,9-xanthene] 3- (Np-tolyl-N-ethyl) Amino) -7- (N-phenyl-N-methyl) fluorane, 6 '-{4- (4-anilino) anilino} -2'-phenylamino-3'-methylspiro [phthalide-3,9-xanthene, 6 '-Diethylamino-2- {4- (4-anilino) anilino} -2'-phenylamino-3'-methylspiro [phthalide-3,9
-Xanthene], 3-3-bis (4'-dimethylamino-2-methoxyphenyl) -4-azaphthalide, 3-3
-Bis (4'-diethylamino-2-ethoxyphenyl) -4-azaphthalide, 3,6-di (N-dimethylamino) -fluorene-9-spiro-3 '-(6'-dimethylamino) phthalide, 3- Diethylamino [a]
Examples thereof include (2,2-dimethyl-4-methyl) -pyridino-fluorane, but are not limited thereto.

As the color former (electron donating color former) used in the present invention, the following color formers known in the art can also be used in combination. (1) As a triarylmethane compound, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone),
3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,
2-dimethylindol-3-yl) phthalide, 3-
(P-Dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenylindole-3-
Yl) phthalide, 3,3-bis- (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide,
3,3-bis- (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis-
(9-Ethylcarbazol-3-yl) -5-dimethylaminophthalide, 3,3-bis- (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3-
p-dimethylaminophenyl-3- (1-methylpyrrol-2-yl-6-dimethyl-aminophthalide, etc.,

(2) As a diphenylmethane compound,
4,4'-bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl leuco auramine, N-
2,4,5-trichlorophenyl leuco auramine, etc.
(3) Rhodamine B-anilinolactam, rhodamine B-p-nitroanilinolactam, rhodamine B-p-chloroanilinolactam as the xanthene-based compound, 3
-Diethylamino-7-dibenzylaminofluorane,
3-diethylamino-7-octylaminofluorane,
3-diethylamino-7-phenylfluorane, 3-diethylamino-7-3,4-dichloroanilinofluorane, 3-diethylamino-7- (2-chloroanilino)
Fluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-
Anilinofluorane, 3-ethyl-tolylamino-6-
Methyl-7-anilinofluorane, 3-ethyl-tolylamino-6-methyl-7-phenethylfluorane, 3-
Diethylamino-7- (4-nitroanilino) fluorane, etc.,

(4) Thiazine-based compounds such as benzoyl leuco methylene blue and p-nitrobenzoyl leuco methylene blue, and (5) spiro-based compounds such as 3-
Methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3'-dichloro-spiro-dinaphthopyran, 3-benzylspiro-dinaphthopyran, 3
-Methylnaphtho- (3-methoxy-benzo) -spiropyran, 3-propyl-spiro-dibenzopyran, etc.,

In addition, JP-A-63-230387 and "Dye for pressure-sensitive and heat-sensitive recording paper" (coloring material, 61 [5] P
292-302. 1988). Alternatively, mention may be made of a mixture thereof. These are determined by the application and the desired properties.

The color former as described above is usually encapsulated in a state in which it is dissolved in a hydrophobic medium, and the hydrophobic medium is not particularly limited as long as it is used for general carbonless pressure-sensitive copying paper. . To give a specific example,
(A) As aromatic hydrocarbon, diarylethane, alkylbiphenyl, alkylterphenyl, alkylnaphthalene, triarylmethane, diphenylalkane, hydroanthracene, hydrophenanthrene, dibenzyltoluene, etc. (b) As mineral oil, kerosene, paraffin ,
Naphthenic oil, chlorinated paraffin, etc., (c) vegetable oil, cottonseed oil, corn oil, coconut oil, etc., (d) alcohol, oleyl alcohol, tridecyl alcohol, benzyl alcohol, 1-phenylethyl alcohol, glycerin, etc. e) Organic acids such as oleic acid,
As the ester (f), dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate, diethyl adipate, propyl adipate,
Di-n-butyl adipate, dioctyl adipate, etc.,
(G) Organic phosphoric acid compounds as tricresyl phosphate, tributyl phosphite, tributyl phosphite oxide, etc., and (h) ethers as phenyl cellosolve, benzyl carbitol, polypropylene glycol, propylene glycol monophenyl ether, etc.
(I) N, N-dimethyllauramide as an amide,
N, N-dimethyl stearamide, N, N-dihexyl octyl amide, etc., (j) ketone as diisobutyl ketone, methyl hexyl ketone, etc., (k) alkyl carbonate as ethylene carbonate, propylene carbonate, etc., or a mixture thereof. I can name it. These are determined by the application and the desired properties.

In the case of microencapsulating the color former, it is possible to use an ultraviolet absorbing substance dissolved in the internal phase as is conventionally used, and it is used for general carbonless pressure-sensitive copying paper. The substance is not particularly limited as long as it is a substance. As a specific example of the ultraviolet absorbing substance,
(A) As salicylic acid type, phenyl salicylate, p
-Tert-butylphenyl salicylate, p-octylphenyl salicylate and the like, (2) dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy as (b) benzophenone type. -4
-Dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, etc.

(C) As a benzotriazole type, 2
(2'-Hydroxy-5'-methylphenyl) benzotriazole, 2 (2'-hydroxy-5'-tert-
Butylphenyl) benzotriazole, 2 (2'-hydroxy-3 ', 5'-di-tert-butylphenyl)
Benzotriazole, 2 (2'-hydroxy-3'-t
ert-Butyl-5'-methylphenyl) -5chlorobenzotriazole, 2 (2'-hydroxy-3 ', 5'
-Di-tert-amylphenyl) benzotriazole, 2 (2'-hydroxy-4'-octoxyphenyl) benzotriazole and the like, as (di) cyanoacrylate-based, 2-ethylhexyl-2-cyano-3,3 '
-Diphenyl acrylate, ethyl-2-cyano-3,
Examples thereof include 3'-diphenyl acrylate and the like, or a mixture thereof. These are determined by the application and the desired properties.

When the color-forming agent is microencapsulated, it is possible to dissolve the UV stabilizer in the internal phase and use it as is conventionally used. The substance is not particularly limited as long as it is a substance.
Specific examples of the ultraviolet stabilizer include (i) nickel bis (octylphenyl) as quenchers.
Sulfide, [2,2'-thiobis (4-t-octylphenolate)]-n-butylamine nickel, nickel complex-3,5-di-t-butyl-4-hydroxybenzyl-phosphate monoethylate, nickel-
As a dibutyldithiocarbamate (b) hindered amine light stabilizer (HALS), a compound having a 2,2,6,6, -tetramethyl-piperidine ring: bis (2,2
2,6,6-tetramethyl-4-piperidyl) sebacate and the like, or a mixture thereof can be mentioned. These are determined by the application and the desired properties.

When the color-forming agent is microencapsulated, it is possible to use an antioxidant dissolved in the internal phase as is conventionally used, and it is a substance used for general pressure-sensitive copying sheets. If there is no particular limitation. Specific examples of the antioxidant include (a) monophenol compounds such as 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6, -di-t-butyl- 4-ethylphenol, stearyl-β- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate, etc.
Methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-ethyl-6)
-T-butylphenol), 4,4'-thiobis- (3
-Methyl-6-t-butylphenol), 4,4'-butylidene-bis- (3-methyl-6-t-butylphenol), etc.
1,3-tris- (2-methyl-4-hydroxy-5-
t-Butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-)
(Hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, tocopherols, and the like, and (d) sulfur-based dilaurylthiodipro Pionate, dimyristyl thiodipropionate, distearyl thiodipropionate, etc. (pho) phosphoric acid type,
Triphenyl phosphite, diphenyl isodecyl phosphite, 4,4'-butylidene-bis (3-methyl-
6-t-butylphenyl-di-tridecyl) phosphite, cyclic neopentanetetraylbis (octadecylphosphite), tris (nonylphenyl) phosphite, diisodecylpentaerythritol diphosphite, 10-decyloxy-9,10 Examples thereof include -dihydro-9-oxa-10-phosphaphenanthrene and the like, or a mixture thereof. These are determined by the application and the desired properties.

The color former having absorption in the wavelength region of 600 to 1000 nm is usually added in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the hydrophobic medium. The other color former is usually added in an amount of 0.1 to 20 parts by weight.

The microencapsulation method used in the present invention is not particularly limited, but the microcapsules obtained by the coacervation method using gelatin, gum arabic or the like generally breaks the film when mixed with latex. Interfacial polymerization method, in situ
It is preferable to use the u polymerization method or the microbe microencapsulation method. The emulsifier used for in situ polymerization encapsulation is preferably a polymer electrolyte. Specifically, styrene-maleic anhydride copolymer, styrene-benzyl methacrylate-maleic anhydride copolymer, α-alkylstyrene-maleic anhydride copolymer, nuclear monoalkyl-substituted styrene-maleic anhydride copolymer, Nuclear dialkyl-substituted styrene-maleic anhydride copolymer, styrene-maleic anhydride monoalkyl ester copolymer, ethylene-maleic anhydride copolymer, polystyrene sulfonic acid, polyacrylic acid, acrylic acid-acrylic acid ester copolymer Aqueous solutions such as, and mixed solutions of these are used.

Emulsifiers used for interfacial polymerization encapsulation include polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, various types (wheat, potato, corn, etc.) in addition to the above in situ encapsulation.
An aqueous solution of starch or the like or a mixed solution of these is also used. In addition, known substances having nonionic, cationic or amphoteric surface-active substances may be added to the extent that they do not cause any problems in the encapsulation process and used in combination.

The size (average diameter) of the color-forming agent-containing microcapsules used in the present invention is preferably in the range of 0.1 to 20 μm, and particularly preferably in the range of 1 to 10 μm. The coating amount of the color former is not particularly limited,
From the viewpoint of color development performance, the range is 5 to 1000 mg / m ² , and particularly preferably 20 to 300 mg / m ² .

An aqueous coating liquid is usually used for coating the microcapsule layer. The color-forming agent-containing microcapsule dispersion obtained by the above-mentioned method may optionally contain a latex binder, a water-soluble binder, Capsule protectant (stilt), white pigment, surfactant, defoamer,
Various auxiliaries known in the art such as a thickener, a preservative and a coloring agent are added and adjusted. The capsule content in the capsule coating liquid is usually 5 to 80 parts by weight per 100 parts by weight of the coating liquid (solid portion).
Adjusted to the range of parts by weight.

Specific examples of the latex type binder used in the present invention include styrene-butadiene type copolymer latex, acrylonitrile-butadiene type copolymer latex, vinyl acetate type, acrylic type latex and the like,
Examples thereof include alkali thickening type latex. Examples of the water-soluble binder include gelatin, albumin, casein, starch, pregelatinized starch, oxidized starch, etherified starch, esterified starch, sodium alginate, arabic gum, carboxymethyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid. Acrylamide, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, methylcellulose, etc. Examples thereof include molecular compounds. These can also be mixed and used. Usually, these are used in amounts of 5 to 100 parts by weight of dry solid microcapsules.
A range of 100 solids by weight is preferred. Particularly preferably,
It is in the range of 5 to 50 solid parts by weight.

The capsule protector (stilt) used in the present invention is preferably a known one such as wheat starch granules, corn starch granules, pea starch granules, various plastic pigments and pulp powders, and its size (average diameter).
Is preferably in the range of 1 to 100 μm. Particularly preferably, the range is 5 to 30 μm. When a white pigment is added to the microcapsule-containing layer, for example, calcium carbonate, aluminum hydroxide, zinc oxide, titanium oxide,
Kaolin, talc, etc. can be used.

As a coating method, coating and drying are carried out by an ordinary coating machine (coater). As a specific coating machine, an air knife coater, a blade coater, a rod coater, a bar coater, a roll coater, a size press coater, a curtain coater or the like is used.

The support used in the present invention is particularly preferably acidic paper or neutral paper mainly composed of cellulose fibers, but is not particularly limited as long as it is a sheet.

The lower paper coated with the developer layer can be obtained by coating the support with a developer as an aqueous or non-aqueous coating liquid, and an aqueous coating liquid is usually used. In addition to the color developer, the coating liquid is added with a binder, a pigment, and if necessary, various known auxiliaries such as a dispersant, a surfactant, an ultraviolet absorber, an optical brightener, a thickener, and a defoaming agent. Then, it is prepared and coated on a support using a coating machine as described above.

Examples of the electron-accepting color developer used in the present invention are not particularly limited, but compounds having a phenolic hydroxyl group, inorganic solid acid compounds, organic solid acid compounds, pressure-sensitive copying sheets and Examples include those used in the field of heat-sensitive sheets. Examples thereof include novolac type phenolic resins and polyvalent metal salts thereof, salicylic acid derivatives and polyvalent metal salts thereof, salicylic acid resins and polyvalent metal salts thereof, and the like.

The salicylic acid derivative is a compound having at least one aromatic substituent, specifically, 3-phenylsalicylic acid, 5-phenylsalicylic acid, 3-benzylsalicylic acid, 5-benzylsalicylic acid, 3- (α-methyl). Benzyl) salicylic acid, 5- (α-methylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) salicylic acid, 5- (α, α-dimethylbenzyl) salicylic acid, 3,5-diphenylsalicylic acid, 3,5-di (Α-
Methylbenzyl) salicylic acid, 3,5-dibenzylsalicylic acid, 3,5-di (α, α-dimethylbenzyl) salicylic acid, 3,5-di (4-methylbenzyl) salicylic acid, and the like, and polyvalent metal salts thereof. Compounds can also be used.

As the salicylic acid resin and the polyvalent metal salt thereof, all of the above-mentioned compounds can be used, but as an example, the above salicylic acid derivative and styrene, o. m. p-
Examples of salicylic acid resins obtained by reacting styrene derivatives such as methylstyrene, α-methylstyrene, β-methylstyrene and the like at a molar ratio of 1: 0.5 to 10 with a Friedel-Crafts reaction in the presence of a strong acid catalyst are polyvalent metal salts. To be Examples of the polyvalent metal include Ca, Mg, Al, Zn, and Mn, but it is most preferable to use it as a zinc salt. These color developers may be used in combination of two or more kinds.

The coating amount of the color developer coating liquid on the support and the amount of the color developer mixed in the color developer coating liquid are not particularly limited, but usually the color developing performance and the economical efficiency are ² to 20 g / m < ² >, more preferably 3 to 15 g / m < ² >, and ^{2 to} 80% by weight, and more preferably 5 to 40% by weight.

Examples of pigments used in combination with the color developer include heavy calcium carbonate, light calcium carbonate, calcium sulfate, kaolin, calcined kaolin, talc, aluminum hydroxide, aluminum silicate, magnesium oxide,
Magnesium carbonate, magnesium sulfate, zinc oxide, activated clay, fine silicic acid, titanium oxide, calcium silicate, urea-
Examples include usual inorganic or organic white pigments such as formaldehyde resin. These developers and pigments are coated on a support together with an adhesive as needed, but an intermediate coating layer made of a pigment, an adhesive, etc. is formed on the support to form a developer layer. Is also good.

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EXAMPLES Next, the features of the present invention will be described in detail with reference to Examples and Comparative Examples. Of course, the present invention is not limited to the Examples, and therefore the substances used, production conditions, etc. are also included in the Examples. It is not limited to the description of. In the examples and comparative examples, unless otherwise specified, it is expressed as parts by dry solid.

Example 1 [Production of Microcapsules Encapsulating Coloring Agent] As a coloring agent,
3,3-Bis- (4-diethylamino-2-ethoxyphenyl) -4-azaphthalide (4 parts) and 3- {1,1-di (1-ethyl-2-methylindole) ethylene} -3
4 parts of-(P-diethylaminophenyl) phthalide was mixed with a diarylethane solvent (Hisol SAS N-296:
A solution dissolved in 92 parts of Nippon Petrochemical Co., Ltd. was prepared.
To 220 parts of a 5% aqueous solution of styrene-maleic anhydride copolymer, 180 parts of the above hydrophobic liquid was gradually added with vigorous stirring, and stirring was continued until the 50% volume average diameter on a Coulter counter became 5 μm to emulsify. A liquid was obtained. Separately, 11 parts of melamine, 21 parts of 37% aqueous formaldehyde solution, and 28 parts of water were dissolved by heating to obtain an aqueous solution of melamine-formaldehyde initial condensate, which was added to the emulsion and stirred at a temperature of 70 ° C. for 2 hours. A microcapsule solution was obtained.

[Preparation of sheet coated with inorganic solid fine particles] 60 parts of kaolin (Thiele kaolin Co.)
15 parts of styrene-butadiene copolymer latex (manufactured by Japan Synthetic Rubber Co., Ltd.) and 25 parts of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Co., Ltd.) were added to obtain a coating solution. The coating solution blade coating, dry coating amount to obtain an inorganic solid fine particle coating sheet is applied and dried on a high-quality paper 41 g / m ² as a 3.0 g / m ^2.

[Preparation of carbonless paper (CB)] Wheat starch 70 was added to 100 parts of the color-forming agent-encapsulating microcapsules.
Part, and 35 parts of styrene-butadiene copolymer latex (manufactured by Japan Synthetic Rubber Co., Ltd.) were added to obtain a color developer coating solution. By the air knife coating method, the coloring agent coating solution was coated on the above-mentioned inorganic solid fine particle coating sheet at different coating amounts to obtain a carbonless upper paper (CB).

[Bar Code Printing] The obtained carbonless upper paper and commercially available carbonless lower paper (Mitsubishi NCR paper N-40, manufactured by Mitsubishi Paper Mills Ltd.) were combined to produce a dot printer YL-5545 (Sanwa). A bar code was printed using Technos Co., Ltd.). The barcode used was CODE-39.

[Evaluation of Copy Bar Code] With respect to the bar code copied on the carbonless lower sheet, the bar code analysis rate, the standard deviation of the bar code analysis rate, and the PCS density are measured by a bar code verifier LASERCHECK II (OLYMPUS-S).
YMBOL). The data was measured at 10 points on the bar-printed portion and averaged. The barcode analysis rate is
This is a value that LASERCHECK II independently verifies, and the higher the value, the better the bar code reading performance. The reading wavelength is 670 nm, and the PCS concentration is PCS concentration =
(A−B) / A {A: maximum value (%) of reflectance of space portion, B: minimum value (%) of reflectance of bar portion}, which is a value of 0 to 1 and is generally In addition, the higher the PCS value, the clearer the image identification and the higher the reading performance.

Example 2 In Example 1, the kaolin used in the sheet coated with the inorganic solid fine particles was changed to aluminum hydroxide (Hidilite H-
42, manufactured by Showa Denko Co., Ltd.).

Example 3 In Example 1, the kaolin used in the inorganic solid fine particle coated sheet was changed to calcium carbonate (ESCALON # 220).
No. 0, manufactured by Sankyo Seiko Co., Ltd.).

Example 4 In Example 1, the kaolin used in the sheet coated with inorganic solid fine particles was changed to calcium carbonate (Tamapearl TP-22).
2H, manufactured by Okutama Kogyo Co., Ltd.)
I went the same way.

Example 5 Except that the coating amount of the inorganic solid fine particle coating layer was 8 g / m ² .
A carbonless upper paper was obtained in the same manner as in Example 1.

Example 6 As a color former, 3,3-bis- (4-diethylamino-
2-ethoxyphenyl) -4-azaphthalide (3 parts),
All the same as in Example 2 except that 3 parts of 3,3-bis (4-dimethylamino) -6-dimethylaminofluorene and 2 parts of 3-dibutylamino-6-methyl-7-anilinofluorane were used. I got a carbonless paper.

Example 7 A carbonless top paper was obtained in the same manner as in Example 6 except that the coating amount of the inorganic solid fine particle coating layer was 2.5 g / m ² .

Comparative Example 1 In the above-mentioned Example 1, a high-quality paper of 41 g / m ² was used in place of the inorganic solid fine particle coated sheet, and 70 parts of wheat starch was used as 35 parts.
Part, a different amount of the coloring agent coating liquid in which 35 parts of styrene-butadiene copolymer latex is changed to 18 parts is applied.
It was dried to obtain a carbonless paper. Using the obtained carbon-free paper, the copy barcode was evaluated in the same manner as in Example 1.

The evaluation results of the CF bar code reading performance are summarized in Table 1.

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[Table 1]

As is apparent from Table 1, when bar code printing is performed using the carbonless pressure-sensitive copying paper of the present invention, the pressure transmission becomes uniform due to the influence of the inorganic solid fine particle coating layer, and an extremely clear color image is formed. As a result, the bar code analysis rate was high in the examples, and there was little variation in measured values, and good readability was obtained. On the other hand, in the comparative example, the barcode analysis rate was as low as 80% or less, and the measured values were uneven.

[0058]

According to the present invention, a carbon-free pressure-sensitive copying paper for optical reading, which exhibits excellent optical reading performance with a small amount of coloring agent applied, was obtained.

Front page continued (72) Inventor Makoto Fujita 34-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Paper Mills, Ltd.

Claims (3)

[Claims] 1. A carbonless pressure-sensitive copying paper for optical reading capable of optically reading a color-developed image by a color-forming reaction between an electron-donating color developing agent and an electron-accepting color developing agent in a wavelength region of 600 to 1000 nm. A carbon-free pressure-sensitive copying paper for optical reading, characterized in that a pigment layer mainly composed of inorganic solid fine particles and an adhesive is provided on a support, and an electron-donating color former-containing microcapsule-containing layer is provided thereon. 2. The coating amount of the pigment layer provided on the support is
The carbonless pressure-sensitive copying paper for optical reading according to claim 1, which has a weight of 3.0 to 8.0 g / m ² . 3. The inorganic solid fine particles are JIS K5101.
The carbonless pressure-sensitive copying paper for optical reading according to claim 1 or 2, wherein the oil absorption amount according to the above is 20 to 40 ml / 100 g.