JPS61137770A - Pressure-sensitive recording sheet - Google Patents

Abstract

PURPOSE:To enhance light resistance of a microcapsule layer and light resistance of a color forming material, by incorporating a specified diphenylamine derivative into microcapsules which contain a substantially colorless electron- donative dye. CONSTITUTION:A diphenylamine derivative of general formula [I], wherein each of Ar1 and Ar2 is 6-18C aryl, and R is 1-15C alkyl or 7-18C aralkyl, is incorporated into the microcapsules which contain a substantially colorless electron-donative dye, in a pressure-sensitive recording sheet. The derivative is preferably used in an amount of 10-30wt% based on the amount of a color former. The derivative is added to and dissolved in a solution of the color former in an organic solvent, the resultant solution is microencapsulated, and the microcapsules are applied to a base. The color former used in the recording sheet is not particularly limited, and may be a triarylmethane compound, a diphenylmethane compound or a mixture thereof. The color former is dissolved in a solvent, and the resultant solution is encapsulated to be applied to the base.

Description

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

(Prior art) A pressure-sensitive recording sheet supports a microcapsule layer containing microcapsules in which a nearly colorless electron-donating dye (hereinafter referred to as a coloring agent) is dissolved in an appropriate solvent and the resulting oil droplets are microencapsulated. A top paper coated on a support, a bottom paper coated with a developer layer containing an electron-accepting compound (hereinafter referred to as a developer) on another support, and in some cases one side of the support. A combination of paper sheets coated with a microcapsule layer on one side and a color developer layer on the other side, or a support containing the capsules and a color developer on the same side, or There are capsules that contain one of the capsules or the color developer and the other coated with the other.

These pressure-sensitive recording papers are described, for example, in US Pat.
No. 470, 2. ! 01. 'AI? No. 2゜yo 10.
No. 1471, same, 730. tA17, 3, ψ/
r, Ar0 No., etc.

However, these pressure-sensitive recording sheets have the following two practically serious drawbacks.

(1) The light resistance of the microcapsule layer containing the color former is insufficient. ...The color development property decreases due to light irradiation of the microcapsule layer.

(2) The light resistance of the coloring material is insufficient. ...The density of the coloring body decreases when the coloring body is irradiated with light.

In order to improve the light resistance of color formers in pressure-sensitive recording sheets, attempts have been made to use hydrogen quinoline derivatives, p-phenyl diamine derivatives, and the like.

However, even when these compounds were used, the effect of improving the light resistance of the color former was insufficient. Furthermore, these compounds have little effect on improving the light resistance of the microcapsule layer.

(Object of the Invention) An object of the present invention is to provide a pressure-sensitive recording sheet in which the light resistance of the microcapsule layer containing a color former and the light resistance of a color former are significantly improved.

(Structure of the Invention) The object of the present invention is achieved by a pressure-sensitive recording sheet characterized by containing a diphenylamine derivative represented by the following general formula (IJ) in microcapsules containing an almost colorless electron-donating dye. It was done.

Ar 1-N Ar2(I J (wherein, Arl and Ar2 are aryl groups having 4 to 1 carbon atoms, R is an alkyl group having 1 to 1 carbon atoms,
Or it represents an aralkyl group having 7 to 1 carbon atoms. ) In the above general formula (IJ), Ar1 and Ar2 are preferably aryl groups having t to /3 carbon atoms, and it is particularly preferable that at least one of Ar1 and Ar2 has an alkoxy group, an aryloxy group, or an aralkyl group.

R is an alkyl group having carbon atoms/-r and carbon atoms 7 to
10 aralkyl groups are preferred.

Specific examples of these compounds are shown below.

(1) 4'-Methoxy-N-methyldiphenylamine (11) ≠-ethoxy N-methyldiphenylamine < +i+ ) ≠-methoxy N-ethyldiphenylamine (1v) ≠-ethoxy N-ethyldiphenylamine CV) Hiro-methoxy-N- Inpropyldiphenylamine (l IA-ethoxy, y-N-isopropyldiphenylamine < v+i J Hiro-methoxy N-7' tyldiphenylamine c vm > μm methoxy-N-penzyldiphenylamine (1x) ≠-methoxy N-octyl Diphenylamine (x) 3-methoxy-N-methyldiphenylamine (XI) Hiro-isopropoxy-N-ethyldiphenylamine (x+N, +-methyl-≠-methoxy-N-ethyldiphenylamine (x111) 2-methyl-ψ -Ethoxy N-ethyldiphenylamine (XIV) 4', lA'-shift-1i' C-N-methfk diphenylamine (Xv) ≠-chloroμ'-methoxy N-methyldiphenylamine (Xvl) -2-chloro-Hiroshi '-Method N-methyldiphenylamine (XVil) 2-Chlor-Hiro-Method N-ethyldiphenylamine (Xv1wa) 4cmphenol N-ethyldiphenylamine (XIX) ) J-benzylo-Naka Chiro'-methoxy-N
- Ethyldiphenylamine The preferred amount of the diphenylamine derivative used is 10 to 100% of the color former, more preferably 0 to 100% of the color forming agent used.
The amount is X.

The diphenylamine derivative can be added by dissolving it in an organic solvent solution of a color former, forming microcapsules from this solution, and applying the microcapsules to a support.

The color formers used in the recording sheet of the present invention are, but are not limited to, medium compounds of these color formers:
Examples include triarylmethane-based compounds, diphenylmethane-based compounds, xanthine-based compounds, thiazine-based compounds, splint compounds, and mixtures thereof.

These color formers are dissolved in a solvent, 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, kerosene, naphthenic oil, alkylated biphenyls, alkylated terphels, chlorinated ξ roughhenes, 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.

In preparing a coating solution containing microcapsules containing a coloring agent, a water-soluble binder and latex binder are generally used. 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 phenolic resins. can give.

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

The performance of the microcapsule sheet for pressure-sensitive recording 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, tr parts of calcium carbonate and 3 parts
．． To the solution in which μ parts of zinc α-methylbenzylsalicylate were added and mixed, and then dispersed for 30 minutes using an attritor, 2.
j part and 10 wt% PYA (saponification degree vertical polymerization degree 100
0) 72 parts of an aqueous solution was added and stirred uniformly to obtain a coating solution. Apply this coating liquid to 10g/m2 of base paper K 4Cg/m2
(7) A color developer sheet was obtained by coating and drying using an air knife coater capable of coating solid content.

(Example of the invention) The present invention will be explained in more detail with reference to Examples below.

The invention is not limited to the examples.

Examples 1-13 Partial sodium salt of polyvinylbenzenesulfonic acid adjusted to pH 4AvC (average molecular weight).

A coloring agent oil prepared by dissolving crystal violet lactone Hirobe and ≠ part of the diphenylamine derivative shown in Table 1 in 100 parts of /-phenyl-/-xylylethane was emulsified and dispersed in μ and μ water-soluble Hioo parts of 00) to obtain average particles. An O/W emulsion with a diameter of g and tμ was obtained. Separately 2 parts of melamine, 37%
Formaldehyde aqueous solution/1 part, water r3 parts to 0c
After heating and stirring for 30 minutes, a transparent mixed aqueous solution of melamine, formaldehyde and melamine-formaldehyde initial condensate was obtained. This mixed aqueous solution was added to and mixed with the emulsicon, and the pH was adjusted to 6.0 with 20% acetic acid aqueous solution while stirring. The temperature of the solution was adjusted to 0, and the liquid temperature was raised to aroc and maintained for 30 minutes to complete the encapsulation.

To this liquid were added 200 parts of a 20% aqueous solution of etherified starch, starch particles (average particle size lLoμ)≠7 parts, and 0 parts of Tal 2F.

Then, water was added to adjust the solid content concentration to 20% VC to prepare a microcapsule liquid.

This microcapsule liquid was dried and coated on a base paper of ≠0177 m2 using an air knife coater so that the weight was 1 g and 7.2 g, and dried to obtain a microcapsule sheet.

Comparative Example Instead of the color former oil in Example, crystal violet lactone Hirobe was added to 10 l-phenyl-7-xylylethane.
A comparative microcapsule sheet was obtained in the same manner as in the example except that a color former oil dissolved in 0 parts was used.

Comparative test (1) Light resistance of microcapsule layer The microcapsule layers of the example and comparative microcapsule sheets were irradiated with a fluorescent light fading tester (33,0001 ux) for μ hours, and then stacked on a developer sheet. , JOOKy
A load pressure of /cm 2 was applied to develop color. After leaving it in the dark for λμ time, the wavelength was 3r.

The spectral absorption curve of the color former between ~7rOnm was measured, and the concentration at the absorption maximum was measured.

Separately, unirradiated Example and Comparative microcapsule sheets were stacked on a color developer sheet, and a load pressure of J 00 KP /cm2 was applied to develop color. After leaving it in a dark place for 2 hours, the spectral absorption curve of the chromophore between wavelengths 3ro to 7ronm was measured, and the concentration at the thickest absorption (fresh concentration (DO
)) was measured.

The measurement of the spectral absorption curve was carried out using Hitachi Color Analyzer 307.
Table 1 shows the light fastness values determined using a mold using the following formula.

The larger the power of incident light, the better the light resistance of the microcapsule layer.

(2) Light resistance of color formers The microcapsule sheets of Example and Comparative Microcapsules were placed on a color developer sheet and a load of j00 KP/cm 2 was applied to develop color. After leaving it for 24 hours in a dark place, the wavelength is 310 ~
The spectral absorption curve of the color former between 710 nm was measured, and the concentration at the absorption maximum (fresh concentration (Do)) was measured.

This color body is measured using a Gisenon fade meter (Suga Test Instruments,
After irradiation with FAL-λjAX-HC type), the spectral absorption curve of the chromophore was measured, and the concentration CD at the absorption maximum was determined.
) was measured.

The measurement of the spectral absorption curve was carried out using Hitachi Color Analyzer Model 307, and the light fastness values determined by the following formula are shown in Table 1.

The fresh density (DoJ) at the absorption maximum after irradiation with a senone fade meter indicates that the larger the light fastness value, the better the light fastness of the coloring material.

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

Procedural amendment (side 1985≠Month/Date 2, Name of the invention Pressure-sensitive record sheet 3, Person making the amendment Relationship to the case Patent applicant Location 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Name (520) Fuji Photo Film Co., Ltd. Contact information 2 Nishi-Azabu, Minato-ku, Tokyo 106
No. 26-30 Fuji Photo Film Co., Ltd. Tokyo Head Office Telephone: (406) 253-7 4. Date of amendment order: March 1985 (shipment date) Specification No. 1 containing the item “Detailed Description of the Invention”
Replace the page.

Claims (1)

[Scope of Claims] A pressure-sensitive recording sheet characterized by containing a diphenylamine derivative represented by the following general formula [I] in microcapsules containing an almost colorless electron-donating dye. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (In the formula, Ar_1 and Ar_2 are aryl groups with 6 to 18 carbon atoms, R is an alkyl group with 1 to 15 carbon atoms, or 7 to 18 carbon atoms. represents an aralkyl group.)