JPS61137771A - Thermal recording paper - Google Patents

Abstract

PURPOSE:To meet the requirements for easier arrangement and sorting of printed matter, by a method wherein a colored dye or pigment is incorporated in a base, and the maximum of visible spectral absorption of the base is set to be not lower than a specified value. CONSTITUTION:A raw paper is colored by, for example, adding a colored dye or pigment to a slurry in the step of preparing a pulp slurry. The colored dye or pigment may be one which is used in paper, textile or paint industry or other industries, and the amount thereof, which depends on the absorbance of the dye or pigment and the basis weight of a raw paper, is 10-500mg/m<2>, preferably, 20-200mg/m<2>. To obtain the desired effect, the maximum of visible spectral absorption of the surface of the raw paper is not lower than 0.2, preferably, 0.2-1.0. If the maximum is lower than 0.2, it is difficult to distinguish hues, whereas if the maximum is higher than 1.0, contrast between a printed part and the ground is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a thermal recording paper, and more particularly, it uses an electron-donating dye precursor and an electron-accepting compound that develops a color by reacting with the dye precursor. Regarding thermal recording paper.

(Prior art) Thermosensitive recording paper is a paper that uses physical and chemical changes in substances caused by thermal energy to produce an image of a single image.
process is being studied.

So-called wax-type thermosensitive recording paper has been known for a long time as a paper that takes advantage of the physical changes in substances caused by heat, and is used for electrocardiograms and the like. In addition, various types of coloring mechanisms have been proposed that utilize chemical changes caused by heat, but a two-component coloring type thermosensitive recording paper is particularly representative.

Two-component color-forming thermosensitive recording paper is made by dispersing two types of heat-reactive compounds in the form of fine particles, mixing them with a binder, etc., so that the two types of heat-reactive compounds are separated by the binder, etc., and forming a support. One or both of them are melted by heating and the coloring reaction that occurs when they come into contact is used to obtain records. These two types of heat-reactive compounds are
Generally, they are called electron-donating compounds and electron-accepting compounds.

These two-component color-forming thermal recording papers are (])-secondary color-forming and do not require consideration, (2) the paper quality is close to that of ordinary paper, and (3)
) It has many advantages as a recording sheet, such as being easy to handle. In particular, those using dye precursors as electron-donating compounds have further advantages such as (4) high color density, and (5) easy production of thermal recording paper with various color hues, and are of great utility value. . Therefore, it is the most commonly used thermal recording material.

In recent years, with the development of electronic technology, facsimiles, measuring instruments,
Thermosensitive recording paper is attracting attention as a means for printing out information, such as in printers. Along with this trend, the requirements for recording paper have diversified, and the conventional maximum value of visible spectral absorption has changed to 0.
/! It is no longer satisfactory to simply form a colored image on a blank base paper. That is, when a plurality of recording devices are used, it is necessary to visually determine whether recorded data has been printed out by a different recording device.

(Object of the Invention) An object of the present invention is to meet the various demands for heat-sensitive recording paper as described above, particularly the need to facilitate the sorting and classification of printed matter.

(Structure of the Invention) The object of the present invention is achieved by coloring the support of thermosensitive recording paper. Specifically, this was achieved by containing a colored dye or pigment in the support and setting the maximum visible spectral absorption of the support to 0.2 or more.

Next, a method for manufacturing the thermal paper of the present invention will be described.

The thermal paper of the present invention is produced by separately applying an electron-donating dye precursor (hereinafter referred to as a color former) and an electron-accepting compound (hereinafter referred to as a color developer) to a ball mill, a sand mill, an attritor, a three-roller mill, or the like. The particles are dispersed in a water-soluble polymer solution to have an average particle size of 0.01 to 70 microns. Further, when it is necessary to improve the thermal sensitivity, a thermofusible substance having a melting point of j00C or more/zo0c or less is dispersed by the same means. The thermofusible substance may be mixed and dispersed with a color former or developer.

A color forming agent, a color developer, and a thermofusible substance if necessary are mixed after being dispersed, and a colorless to light-colored oil-absorbing pigment, a wax dispersion, an FM dispersion, and the like are added as necessary.

The preferred ratio of color former and color developer during mixing is l:
l to l:j. Also, if a thermofusible material is added, jQ to 200XIk percent relative to the developer is preferred. As for oil-absorbing facial weight, JIS-ni-
It is preferable that the oil absorption amount by O/ is 3 owtt7toog or more, and the amount added is equal to the total of the color former, color developer, and thermofusible substance! O to CoOO weight percentages are preferred. When adding wax or female molding agent, add coloring agent I.
O weight percent to 300 weight percent e-cents is preferred.

Examples of the coloring agent used in the present invention include triarylmethane compounds, diphenylmethane compounds, xanthine compounds, thiazine compounds, and spiropyran compounds. Some of these are exemplified by 3.3-
Bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (i.e. crystal violet lactone)
, 3. J-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-J-(/.

Coke methylindol-3-yl) 7thalide,! −(
p-dimethylaminophenyl)-! -(nomethylindole-3-yl)phthalide, 3-(p-dimethylaminophenyl)-J-(nophenylindole-3-ylnophthalide, J+3-bis-(/, 2-dimethylindole-3-ylno) Yoichi dimethylamino 7-thallide,
3.3-bis(/,λ-dimethylindol-3-yl)-4-dimethylaminophthalide, 3.3-bis(P-
Ethyl (lupazol-3-yl)-! -dimethylaminophthalide, 3,3-bis-(2-phenylindole-
3-yl)-yo-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-(/-methylpyrrol-noyl)-6-dimethyl-anophthalide 3-diethylamino-7-methoxyfluoran, 3-diethylamine -6-methoxyfluorane, 3-diethylamino-7
-dipendylaminofluorane, 3-diethylamino-
6-Methyl-7-anilinofluorane, 3-N-ethyl-N-tolylamino-6-methyl-7-7nilinofluorane, J-N-methyl-N-tolylamino-t-methyl-7-anilinofluorane , 3-piperidino-t-methyl-7-anilinofluorane, 3-diethylamine-t-chloro-7-anilinofluorane, 3-N-cyclohexyl-N-methylamino-bu-methyl-7-ani Linofluorane, 3-piperazino-t-methyl-7-(p-
methylanilino)fluoran, 3-diethylamino-7
-(o-chloroanilino)fluorane, J-diethylamino-7-butylazunofluorane, 3-diethylamino-7-diphenethylaminofluorane, 3,7-bis(methyltolylamino)fluorane, 3-dihydrino7 -7enethylaminofluorane, J-diethylamino-7-phenylfluorane, 3diethylamino-7,t
- Benzofluorane, etc.

These may be used alone or in combination for the purpose of color tone adjustment.

The color developer used in the present invention includes a fetol compound,
Examples include hydroxy-7benzoic acid derivatives and salicylic acid derivatives. Examples include: Corbis(μ'-hydroxy-7phenyl)propane (bisphenol A), 2.Corbis(tA-hydroxy-7phenyl)propane, λ, 2-bis(tA/-hydroxy-3', yo'-dichloro7-niphenylhexane, /, /-bis(4c/-hydrocyphenylenecyclohexane, 2.-bis(μ'-hydrocyphenylphenylhexane, 1./-bis(IA/- Hydroxyphenylnopropane, /, l-bis(4c/- and 7 phenylbutane, /l/-bis(μ′-hydrocyphenylnohentane, 1.l-bis(≠′-hydroxyphenylon) Usan, /, /-his(μ'-hydroxyphenyl]hebutane, /, /-bis(lA/-hydroxyphenyl)octane, /, l-bis(lA/-hydroxyphenyl)-comethyl-pentane, ll/-
Bis(Hirohitokushi diphenyl no λ-ethyl-hexane, /.

/-bis(≠′-hydroxyphenylundodecane p-ri<ruphenol, ri-phenyl7e/-A/, p-
Benzyl hydroxybenzoate, butyl p-hydrocybenzoate, phenethyl p-hydroboxybenzoate, 3. j-
di-tert-butylsalicylic acid, 3. J--G-α-
Examples include methylbenzylsalicylic acid and 3-α-methylbenzylsalicylic acid. Zinc and aluminum salts can also be used as salicylic acid derivatives.

Examples of the thermofusible substance used in the present invention include higher fatty acid amides, benzoic acid ester derivatives, naphthol derivatives, naphthoic acid derivatives, and urea derivatives. For adults, stearic acid amide, palmitic acid amide, oleic acid amide, erucic acid amide, ethylene bisstearamide, benzyl p-benzyloxybenzoate, p-butoxan J & hensyl fragrant, β- Naphthol benzyl ether, α-naphthol benzyl ether, α-hydroxy-β-naphthoic acid phenyl ester, β-hydroxy-
Specific examples of oil-absorbing pigments include α-naphthoic acid phenyl ester, β-sulfthoic acid phenyl ester, β-naphthol-(p-chlorobenzyl) ether, and barium carbonate.

Examples include aluminum hydroxide, barium carbonate, barium sulfate, Merck, waxite, kaolin, calcined kaolin, zinc oxide, diatomaceous earth, amorphous silica, lithopone, titanium oxide, urea-formalin resin filler, polyethylene filler, and the like.

Specific examples of wax include polyethylene wax, paraffin wax, microcrystalline wax, and carnauba wax.

As the mold release agent, metal salts of higher fatty acids are preferred, such as zinc stearate, aluminum stearate, calcium stearate, and the like.

When dispersing color formers and color developers, water-based polymers are added as protective colloids, and these water-based polymers are preferably compounds that have a solubility of r1 or more in 2j'C water. Specifically, methylcellulose, calxoxymethylcellulose, hydroxyethylcellulose, starches, gelatin, gum arabic, casein, styrene-maleic anhydride copolymer salt, ethylene-ruic anhydride copolymer salt, imbutylene-maleic anhydride copolymer salt, etc. Examples include polymer salts, polyvinyl alcohol, and carboxymodified polyvinyl alcohol.

These water-soluble polymers also serve as a binder when applying the heat-sensitive material to the support.

The heat-sensitive coating liquid prepared as described above is applied onto colored base paper to form heat-sensitive recording paper.

Methods for coloring base paper include adding colored dyes or pigments to the slurry during the pulp slurry preparation stage, and adding colored dyes or pigments to the size press liquid in the sipe press or C-to in the papermaking process. Alternatively, when processed paper such as coated paper is used as a support, a colored dye or pigment may be added to the coating color.

As the colored dyes or pigments used in the present invention, those used in the paper, textile, paint industries, etc. can be used. Colored inorganic pigments include chrome yellow, iron oxide pigments, molybdate orange, Cadmium red, Prussian blue, zinc sulfide compounds, cadmium sulfide compounds, silicate compounds, etc. are used as organic pigments, such as azo pigments such as...Nza yellow, benzidine yellow, Hansa orange, dinitraniline orange, benzidine orange, Para red, toluidine red. , pyrazolone red,
Phthalone-72 pigments such as linole red, hon red, maroon, etc., such as conomyphthalocyanine blue, copal polyfluoro-7 thalocyanine blue, etc., and anthraquinone pigments such as industrone blue, indibenzatron violet, anthanthrone orange, etc.

Dyes include safranin, rhodamine, magenta, alizarin red, lupine red, chrysoidine, acetamine orange, auramine, quinoline, eucrysin yellow, first light yellow, stilbene yellow, azo yellow, methanil yellow, guictolia green, anthra Available colors include life non green, naphthol green, methylene blue, indigo, diazo blue, naphthol blue, fast blue, xylene blue, methylene violet, crystal violet, Bismarck brown, and chrome brown.

These dyes and pigments may be used alone or in combination. The amount used varies depending on the absorbance of dyes and pigments and the basis weight of the base paper, but it ranges from 10.497 m2 to j O(7'
n9/-% preferably 20 rn9/m
2 to 200 tQ/rn2, but in order to obtain the effects of the present invention, the maximum value of visible spectral absorption on the surface of the base paper is 0.2 or more, preferably Oo, 2 or more and i, o or less. When the maximum value is 0.2 or less, it is difficult to distinguish between hues, and when the maximum value is 0.2 or more, the contrast with the printed portion decreases. The maximum value of visible spectral absorption referred to here is the maximum value of absorbance when monochromatic light with a wavelength of jJ'Onm to 710 nm is irradiated.

The heat-sensitive coating liquid is applied onto the base paper obtained in this manner using a conventional coating method such as a bar coater, a blade coater, or a coater.
7-f It is coated and dried using an if coater, a roll coater, a gravure coater, etc., and is finished by calendering if necessary.

The preferred coating amount is J/l/rn to λ, 7 g/, 2, more preferably ufl/r as solid content.
It is n2 to 1117 abuse.

Further, as the support, it is also possible to use colored paper-like materials such as coated paper and synthetic paper.

When calendering is applied, the smoothness of the coated surface should be 200 seconds or more and xooo seconds or less, and even K)'! ,, preferably 4'00 seconds or more and 7000 seconds or less and 7000 seconds or less.

(Examples of the Invention) Examples of the present invention are shown below, but the present invention is not limited thereto.

Examples 1 to 5 Coanilino 3-chloro-6 as an electron-donating dye
-Dinithylaminofluorane 209! Disperse with 700g of S polyvinyl alcohol (Kura-Shi PVA/17) aqueous solution in a ball mill for a day and night to make liquid A〇λ, 2-bis(P-hydroxyphenyl)propane OtsuQ
1 was dispersed overnight with a % polyvinyl alcohol aqueous solution Ooog and stearic acid amide 601 to obtain Solution B.

Calcined kaolin (Ansilex 0
) 100ji to 7% sodium hexametaphosphate solution 1
Disperse together with 00fi using a homogenizer to obtain liquid C.

Mix liquids A, B, and C, and add 30% zinc stearate.
A heat-sensitive coating liquid is made by adding a separation liquid (Middle East Oils and Fats, Idlin, Z-7) toy. This was dried and applied on the colored high-quality paper shown in Table 1 having a basis weight tog/m2. jj/m
Apply it with a Meyer bar so that it is! Dry at 06C for j minutes, perform beef yarenda treatment, and the surface smoothness is SOO.
It was finished so that it would be a second.

Comparative Example A heat-sensitive coating solution obtained in the same manner as in Example 1 was applied by VC onto a general white base paper.

The print density of the obtained heat-sensitive recording paper was measured in copy mode using a MiniFax ■ type facsimile manufactured by Dentsu Corporation. The measurement was carried out using a Macbeth RD-5'/r type reflection densitometer in visual mode.

Contrast was defined as the difference between background density and print density.

As is clear from Table 1, according to the present invention, thermal recording paper with different hues that are easily distinguishable can be produced without impairing print density.

Claims (1)

[Claims] In thermosensitive recording paper in which a heat-sensitive color forming layer containing as a main component an electron-accepting compound that develops color by reacting with an electron-donating dye precursor and a nuclear dye precursor is provided on a support, the support is made of a material that absorbs visible spectral light. A thermal recording paper characterized by using colored base paper having a maximum value of 0.2 or more.