JPS6367180A - Recording sheet - Google Patents

Abstract

PURPOSE:To improve the light resistance of a microcapsule layer, by containing p-substituted aminophenylindolylazaphthalide derivative and ultraviolet ray absorbing agent. CONSTITUTION:Preferably, a compound shown by formula I is employed as p-substituted aminophenylindolylazaphthalide compound which is employed as a color former. Preferably, benzotriazol ultraviolet ray absorbing agent having spectral absorption in the range of 270-380mmu is employed as an ultraviolet ray absorbing agent. When said derivative is contained by 30wt% or more of the entire quantity of color former, the rigidity of coloring material is improved, then said coloring material is dissolved together with the ultraviolet ray absorbing agent into a solvent and encapsulated so as to be applied onto a supporting material. Natural or synthetic oil can be employed independently or in combination as the solvent. The microcapsule is produced through interfacial polymerization, inner polymerization, phase separation, outer polymerization, coacervation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a recording sheet, and more particularly to a recording sheet that utilizes a color-forming reaction between a nearly colorless electron-donating dye and an electron-accepting compound.

(Prior art) Recording sheets using nearly colorless electron-donating dyes (hereinafter referred to as color formers) and electron-accepting compounds (hereinafter referred to as color developers) can be used for pressure-sensitive paper, thermal paper, light-sensitive pressure-sensitive paper, and electrically conductive heat-sensitive paper. It is already known as recording paper, etc.

For example, British patent, l/g0≠t, US patent≠1tl
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The performance that a recording sheet should have is (1) sufficient color density and color development sensitivity, (2) no fogging, (3) sufficient fastness of color body, and (4) color development. The light resistance of the microcapsule layer containing the agent is sufficient.

It has already been proposed to use p-substituted aminophenylindolyl azaphthalide derivatives as color formers that provide color formers with extremely excellent fastness in these recording sheets (Tokuko Shoyu/-It, Ir07, Special Publication Sho!l-312113, Special Publication Sho1111-2O77 Special Publication Sho61-1 de 6, etc.).

However, the recording sheet containing this p-substituted aminophenylindolyl azaphthalide derivative in microcapsules has the disadvantage that the light resistance of the microcapsule layer is not sufficient (the color development property decreases when the microcapsule layer is irradiated with light). has.

(Object of the Invention) An object of the present invention is to provide a recording sheet containing p-substituted aminophenylindolyl azaphthalide as a coloring agent in the microcapsules, in which the light resistance of the microcapsule layer is improved. be.

(Structure of the Invention) An object of the present invention is to provide a recording sheet containing microcapsules containing an almost colorless electron-donating dye, wherein the microcapsules contain a p-substituted aminophenylindolyl azaphthalide derivative and an ultraviolet absorber. This was achieved by using a recording sheet that is characterized by the following.

Preferable ultraviolet absorbers are 270 to 3 tOm
It has spectral absorption in μ, for example, salicylic acid-based ultraviolet absorbers such as phenyl salicylate, p-tert-7' tylphenyl salicylate, p-octylphenyl salicylate, co-, ≠-dihydroxybenzophenone, λ-hydroxy- methoxybenzophenone,
2-hydroxy-≠-octoxybenzophenone, 2-
Hydroxy-Hiro-dodecyloxybenzophenone,'
12'-dihydroxy-l-methoxybenzophenone,
2.2'-dihydroxy-≠, μ'-dimethoxybenzophenone, 2-hydroxy-≠-methoxy! -Khenzophenone ultraviolet absorbers such as sulfobenzophenone, 2(2'-hydroxy-!'-methylphenyl)penztriazole, λ(2'-hydroxylta')
-tert-butylphenyl/l/)hencytriazole, 2(2'-hydroxy-3', J-'-di-te)
rt-butylphenyl)benztriazole, 2(2
'-hydroxy-3'-tert--1'tiruta'-
Methylphenyl)-! Chlorobenzotriazole, 2 (
2'-Hydroxy-3',tert-butylphenyl)-terchlorobenzotriazole 1.2(,
Benzotriazole UV absorbers such as 2'-hydroxy-3', tert-amylphenyl)benzotriazole, 2(,2'-hydroxy-μ'-octoxyphenyl)benzotriazole, 2-ethyl There are cyanoacrylate ultraviolet absorbers such as hexyl-2-cyano-3,3'-diphenyl acrylate, ethyl-cocyano, -3,3/-diphenylacrylate, etc. Among these, preferred are benzene. It is a triazole ultraviolet absorber.

The preferred amount of the ultraviolet absorber to be used is from
Weight %, more preferably to, i0θ weight %.

The p-substituted aminophenylindolyl azaphthalide compound used as the color former of the present invention is preferably one represented by the following general formula.

-Yu- In the above formula, one of X and Y represents -N=, the other represents -CH-, and Z is a hydrogen atom, a halogen atom, 01
~C8 alkyl group, C1-C12 alkoxy group, C
6 to C18 aryloxy group, or 07 to C13 aralkyloxy group, W represents a hydrogen atom or a halogen atom, R1 is a hydrogen atom or an unsubstituted or halogen atom having up to 12 carbon atoms, a hydroxyl group, a cyano R2 represents a hydrogen atom, a C1-C8 alkyl group or a C6-C2 aryl group, and R and R4 each independently represent a hydrogen atom or an alkyl group substituted with a lower alkoxy group. It represents an alkyl group having a carbon atom, which is unsubstituted or substituted with a halogen atom, a hydroxyl group, a cyan group, or a lower alkoxy group, a C5-C7 cycloalkyl group, a benzyl group, or a phenyl group, and -NR3R4 represents a pyrrolidinyl group; may be formed.

Preferred coloring agents for the p-substituted aminophenylindolyl azaphthalide compound represented by the above general formula include, in addition to p-substituted aminophenylindolyl azaphthalide derivatives, triphenylmethane phthalide compounds, fluoran compounds, A phenothiazine compound, an indolylphthalide compound, a leucoauramine compound, a rhodamine lactam compound, a triphenylmethane compound, a triazene compound, a spiropyran compound, etc. may be used in combination.

In this case, from the viewpoint of the fastness of the color former, it is desirable to use the p-substituted aminophenylindolyl azaphthalide derivative of the present invention in an amount of 30% by weight or more based on the total amount of the color former.

The color forming agent used in the present invention is dissolved in a solvent together with an ultraviolet absorber, encapsulated, and applied to a support.

As a solvent, natural or synthetic oils can be used alone or in combination. Examples of solvents include cottonseed oil, kerosene, paraffin, naphthenic oil, alkylated biphenyls, alkylated terphels, chlorinated paraffins, alkylated naphthalenes, diphenylalkanes, and the like.

As a method for manufacturing the color former-containing microcapsules, an interfacial polymerization method, an internal polymerization method, a phase separation method, an external polymerization method, a coacervation method, etc. are used.

A water-soluble binder or a latex binder is generally used to prepare a coating solution containing microcapsules containing a color former. Further, a capsule protectant such as cellulose powder, starch particles, talc, etc. is added to obtain a color former-containing microcapsule coating solution.

Examples of color developers that react with the color forming agent used in the recording sheet of the present invention include acid clay, activated clay, attapulgite, zeolite, bentonite, clay materials such as kaolin, metal salts of aromatic carboxylic acids, and phenol resins. can be given.

These color developers are applied to a support such as paper along with a binder such as styrene butadiene latex.

The performance of the recording sheet of the present invention was tested using the following color developer sheet.

(Adjustment of color developer sheet) 70 parts of water, 2 parts of zinc oxide, 17 parts of calcium carbonate, and J
, J--G α-methylbenzylsalicylic acid zinc μ parts were added and mixed, and then the carboxy-modified SBR latex was added to the liquid which was dispersed for 30 minutes using an attritor, and the solid content of carboxy-modified SBR latex was 2.
Yube and 10 wt% PVA (Saponification degree Tata% Polymerization degree 100
0) 12 parts of an aqueous solution was added and stirred uniformly to obtain a coating solution. Apply this coating liquid to r Op / m2 base paper pg/
A developer sheet was obtained by coating and drying using an air knife coater capable of coating a solid content of m2.

(Example of the invention) The present invention will be specifically explained below using Examples.

The invention is not limited to the examples.

Examples 1 to ti and comparative examples! -μ Partial sodium salt of polyvinylbenzenesulfonic acid (average molecular weight zoo, adjusted to pH≠).

Emulsifying and dispersing a coloring agent oil prepared by dissolving the coloring agent and ultraviolet absorber shown in Table 2 in 100 parts of diisopropylnaphthalene into 100 parts of μ, ≠% aqueous solution of 00) with an average particle diameter of ≠, μ
An emulsion with a particle size of . Separately, 2 parts of melamine, 37 parts of a 37% formaldehyde aqueous solution, and 30 parts of water were heated and stirred at 60° C. After 30 minutes, a transparent mixed aqueous solution of melamine, formaldehyde, and melamine-formaldehyde initial condensate was obtained. The pH of this mixed aqueous solution is 6
It was ゜or, o. Hereinafter, this mixed aqueous solution of melamine, formaldehyde, and melamine-formaldehyde initial condensate will be referred to as an initial condensate solution.

The initial condensate solution obtained by the above method was added to the above emulsified mixture, and while stirring, 3.6% by weight hydrochloric acid solution was added to the solution.
The H was adjusted to 6.0, the liquid temperature was raised to 0C, and stirring was continued for 3tO. This capsule liquid was cooled to room temperature, and the pH was adjusted to 0 with 20% by weight sodium hydroxide.

To this capsule dispersion, 100 parts of a 19% by weight polyvinyl alcohol aqueous solution, 70 parts of carboxy-modified SBR latex in terms of solid content, parts of starch particles SO and 10 parts of calcium carbonate were added, and water was added to achieve a solid content concentration of 2Q.
% to prepare a coating solution for microcapsules containing a color former.

Apply this coating liquid to r Op / m base paper at r y /
The mixture was coated using an air knife coater so that a solid content of $2 was coated, and dried to obtain a microcapsule sheet for pressure-sensitive copying.

Comparative test (1) Light resistance of microcapsule layer After irradiating the microcapsule layers of the examples and comparative microcapsule sheets with a fluorescent light fading tester (33,0001 ux) for r hours, they were stacked on a developer sheet, To 300!
1. The color was developed under a load pressure of /cm2. In the dark,
After being left for 2≠ hours, the spectral absorption curve of the coloring body was measured at a wavelength of 310 to 7 rOnm, and the density at the absorption maximum was measured.

Separately, unirradiated Example and Comparative microcapsule sheets were stacked on a developer sheet, and a load pressure of 3θOkf/cm 2 was applied to develop color. After leaving it in the dark for 2≠ hours,
The spectral absorption curve of the chromophore between wavelengths 3♂O and 711'Onm was measured, and the concentration (fresh concentration) at the maximum absorption was determined.
Do)) was measured.

The measurement of the spectral absorption curve was carried out using Hitachi Color Analyzer 307.
Table 2 shows the durability values obtained using the following formula using a mold.

The higher the light resistance value, the better the light resistance of the microcapsule layer.

As shown in Table 2, it can be seen that the microcapsule sheet of the present invention is superior in light resistance of the microcapsule layer by 1 to 1 compared to the comparative microcapsule sheet.

Claims (1)

[Claims] 1. A recording sheet containing microcapsules containing a substantially colorless electron-donating dye, characterized in that the microcapsules contain a p-substituted aminophenylindolyl azaphthalide derivative and an ultraviolet absorber.