JPH02134284A - Pressure-sensitive recording sheet - Google Patents

Abstract

PURPOSE:To enhance the light fastness of a developed color material and to obtain a good developed black hue by incorporating a metal salt of a specific salicylic acid derivative as an electron acceptive coupler and also incorporating a specific fluorane derivative as an electron donating dye. CONSTITUTION:A metal salt of a salicylic acid derivative represented by formula [I] as an electron acceptive coupler and a fluorane derivative represented by formula [II] as an electron donating dye are contained in a pressure-sensitive recording sheet obtaining a developed color image by the reaction of the almost colorless electron donating dye and the electron acceptive coupler. In the formula [I], R11, R12, R13 and R14 are a hydrogen atom or an alkyl group and, in the formula [II], R1 and R2 are mutually independently a hydrogen atom, a 18C or less non-substituted alkyl group, a 18C or less alkyl group substituted with a halogen atom, a hydroxyl group, a cyano group, an aryloxy group, a heterocyclic group or an aryl group, a 5-7C cycloalkyl group, a non-substituted or alkyl-substituted phenyl group and may form a 5-, 7-membered ring as -NR1R2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to the BAIIi pressure-sensitive recording sheet. More specifically, a nearly colorless electron-donating dye precursor (hereinafter referred to as a color former) and an electron-accepting color developer (hereinafter referred to as a color developer) are used.
The present invention relates to a pressure-sensitive recording sheet that obtains an elliptic color image by reaction with a pressure-sensitive recording sheet.

(Prior art) Conventionally, color formers and color developers, such as clay materials such as acid clay, activated clay, attapulgite, zeolite, bentonite, and kaolin, metal salts of aromatic carboxylic acids, and phenol formaldehyde resins, have been used to develop color reactions. Pressure-sensitive recording materials are well known, such as US FF, 2
, ! 0! , 4!70 issue, same co, zoz, atri issue, same co, rzo, u7/ issue, same co, j4!1,346
No., same, 2.7/co.

No. 507, same, 730, <z, No. 1, same, 730
, Hiro! No. 7, same 3. Hiro tr, ko! It is recorded in the Q, Tokukai Sho≠Turco r, Kan//, Tokukai ShojQ-≠4A, OOri, etc.

The properties that a pressure-sensitive recording sheet should have are: 1) high color developing ability (with little decline in color developing ability over time);

2) The coloring body has excellent light resistance.

3) There is little yellowing of the developing surface when exposed to light.

4) A desired coloring hue can be obtained.

etc. can be mentioned.

Among currently known color developers, metal salts of salicylic acid derivatives exhibit the best performance. However, among the above-mentioned properties, the light resistance of the color former is still insufficient when exposed to sunlight for a long time.

In particular, conventional black coloring pressure-sensitive recording sheets have the disadvantage '4I: that the coloring body turns reddish or fades when exposed to light, and there has been a strong desire to improve this.

In addition, the coloring reaction between a fluoran black coloring agent and a commonly known metal salt of a salicylic acid derivative results in a reddish black hue, which is undesirable for use as a recording sheet for black coloring.

For this reason, efforts are usually made to make the hue closer to pure black by mixing other green coloring agents with the black coloring agent. However, a black color recording sheet using a mixture of color formers having different hues has a drawback that the hue changes over time after color development.

(Object of the Invention) An object of the present invention is to provide a pressure-sensitive recording sheet that has a color former that has excellent light resistance and that produces a good black color hue.

(Structure of the Invention) An object of the present invention is to provide a pressure-sensitive recording sheet that obtains a colored image by a reaction between an almost colorless electron-donating dye and an electron-accepting color developer, in which the electron-accepting color developer is prepared by using the general formula [ A pressure-sensitive recording sheet containing a metal salt of a salicylic acid derivative represented by formula (I) and a fluoran conductor represented by general formula (II) as an electron-donating dye was achieved.

In the above general formula (1), among the groups represented by R11s R12, R13, and tt14, a hydrogen atom and an alkyl group having a carbon atom number of /-2.2 are preferable, and in particular a tertiary alkyl group having a carbon atom number of /I Groups are preferred.

Specific examples of the groups represented by R11, R12, R13, and R14 include a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a t-butyl group, a t-octyl group, a t-nonyl group, and a t-amyl group. group, t-dodecyl group, cyclohexyl group, cyclohexylfuclohexyl group, butyl group, hexyl group, octyl group, decyl group, dodecyl group, octadecyl group, hexadecyl group, and the like.

From the viewpoint of water insolubility, the salicyl[8 conductor according to the present invention preferably has a total number of carbon atoms of 13 or more, and particularly preferably has a carbon number of 12 or more.

Also, as a metal for forming a metal salt with the above salicylic acid derivative, c.
Examples include aluminum, calcium, chromium, manganese, iron, cobalt, nickel, copper, barium, zinc, etc. Among these, preferred are zinc, aluminum,
Calcium and nickel are preferred, and zinc is particularly preferred.

Specific examples of salicylic acid derivatives according to the present invention are shown below, but the present invention is not limited thereto.

3,! -Dicyclopentagenylsalicylic acid, 3°! −
Di-t-octylsalicylic acid, 3. j-bis-t-hexylsalicylic acid,! -1-octylsalicylic acid,! - for monononylsalicylic acid, 1-1-dodecylsalicylic acid,!
-octadecylsalicylic acid, J,j-bis-t-nonylsalicylic acid, 311-bis-1-dodecylsalicylic acid,
! -Zinc salts such as cyclohexylcyclohexylsalicylic acid, nickel salts, aluminum salts, calcium salts, and the like.

Specific examples of the fluoran derivatives represented by the above general formula (II) include co-anilino 3-methyl-4-dimethylaminofluorane, co-anilino 3-methyl-to-m:thylaminofluoran, co-anilino 3-methyl-4 -N-methyl-to-(iso-propylene aminofluorane, co-anilino 3-methyl-6-N-methyl-heintylaminofluoran, co-anilino 3-methyl-4-
N-methyl-he-cyclohexylaminofluorane, 2
-anilino-3-methyl-5-diethylaminofluorane, coanilino 3-methyl-4-N-ethylheinamylaminofluorane, coanilino 3-methyl-4-N-methyl-he-isoamylaminofluorane, 2 -anilino-3-methyl-6-sibutylaminofluorane, λ-anilino 3-methyl-t-~-ethylheisobutylaminofluorane, co-anilino 3-
Methyl-4-I'll-ethyl-hexylaminofluorane, co-anilino-3-methyl-6-biveridino-aminofluorane, co-anilino-3-methyl-ethyl-cyclohexylaminofluorane, etc. .

The hue of the colored product obtained by the reaction of the fluoran derivative represented by the general formula (It) with a commonly known metal salt of a salicylic acid derivative (J,j-bis(α-methylbenzyl)zinc salicylate, etc.) is as follows: In contrast to reddish black that turns red or fades when exposed to light, the reaction between a fluoran fermentation conductor represented by general formula (n) and a metal salt of a salicylic acid derivative represented by general formula [I] It was completely unexpected that the hue of the colored material obtained by this method was close to pure black and that it was difficult to turn red or fade when exposed to light.

In addition, the pressure-sensitive recording sheet according to the present invention further uses well-known materials other than the present invention, such as phenol derivatives, metal salts of aromatic carboxylic acids, novolac resins, metal-treated novolac resins, and metal complexes. It's % good.

Examples of these are Tokko Sho-ta No. 302, Tokko Sho-san J-
/4c03 issue, JP-A ShojJ-/4AO Hiro 13, JP-A Sho-san r-j/! No. 10, Tokukai Akira! 7-ko1otrbu issue,
Tokukai Akira! No. r-17012, Japanese Patent Publication Shoj? -//λt No. 6, JP-A-60-7747-RI No. 5, JP-A-47-Itazyr
It is described in No. t etc.

Pigments used in the present invention include zinc oxide, aluminum hydroxide, calcium carbonate, titanium oxide, magnesium carbonate, magnesium oxide, barium sulfate, kaolin, activated clay, Merck, and the like.

The color developer and pigment, together with a dispersant, a water-soluble polymer, and other additives, are mechanically dispersed in an aqueous system using a ball mill, attritor, sand mill, etc. to obtain a dispersion. A part of the color developer can also be used as an emulsion in which the color developer is dissolved in an organic solvent and emulsified in water.

The thus obtained dispersion or emulsion is coated on a support with the addition of a binder.

The final it of color developer applied to the support is 0°7g
/m2~,2.0! i/m2, preferably 0.297m
-/, 097m is appropriate.

Examples of these binders include latexes such as styrene-butadiene copolymer latex, polyvinyl alcohol, maleic anhydride-styrene copolymer, starch, casein, gum arabic, gelatin, carboxymethyl cellulose, methyl cellulose, etc. Natural polymeric substances can be used.

In addition to the fluoran fermentation conductor represented by the general formula (If), the color formers include triphenylmethane phthalide compounds, fluoran thread compounds, phenothiazine compounds, indolyl phthalide compounds, indolyl azaphthalide thread compounds, Leuco auramine compounds, rhodamine lactam compounds, triphenylmethane compounds, triazene compounds, spiropyran compounds, etc. may be used in combination.

The coloring agent used in the present invention is 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, paraffins, naphthenic oils, alkylated biphenyls, alkylated terphels, chlorinated paraffins, alkylated t-phthalenes, 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.

Water-soluble binders and latex binders are generally used to prepare coating liquids containing microcapsules containing color formers. Further, a capsule protectant such as cellulose powder, starch particles, talc, etc. is added to obtain a color former-containing microcapsule coating solution.

(Embodiments of the invention) The present invention will be explained in more detail by way of examples below.

The invention is not limited to the examples.

[Preparation of microcapsule sheet containing color former] [Color former sheet 1] Partially sodium salt (average molecule @ 100,000) of polyvinylbenzenesulfonic acid adjusted to pHII,
A color developer prepared by dissolving 6.0 parts of λ-anilino-3-methyl-6-dinithylaminofluorane as a color former in 10 parts of diisopropylnaphthalene was emulsified and dispersed in 10 parts of a 4Ls aqueous solution to determine the average particle size. , jμ particle size was obtained.

Separately, 3 parts of melamine, 37% by weight formaldehyde aqueous solution, and water J01 (S) were heated and stirred for 3 parts to obtain a transparent mixed aqueous solution of melamine, formaldehyde, and melamine-formaldehyde initial condensate. p) t was 1.0 to t, O. Hereinafter, this mixed aqueous solution of melamine, formaldehyde, and melamine-formaldehyde initial condensate will be referred to as an initial condensate solution. 3.1. Add and mix the initial condensate solution obtained by the above method to the above emulsified mixture and stir. Adjust to p) i'4r:j, Q with a hydrochloric acid solution of N Ryuchi, and the liquid temperature is 1jg-1.
, j"c and continued stirring for 360 minutes. The capsule liquid was cooled to room temperature, diluted with 2011@% sodium hydroxide, and adjusted to O.

To this capsule dispersion, 100 parts of iox polyvinyl alcohol aqueous solution, 10 parts solid content of carboxy-modified SBR latex, 10 parts starch particles JO, and 10 parts calcium carbonate were added, and water was added to bring the solid content concentration to -0.
% to prepare a coloring agent-containing microcapsule coating solution.

Apply 1g7m of this coating liquid to j O/i/m base paper.
The mixture was coated using an Air Chi 7 coater so that the solid content of No. 2 was coated, and dried to obtain a color former-containing microcapsule sheet.

[Color former GITCO]

As a coloring agent for [coloring agent sheet 1], Coa Nirif-3
Coanilino 3-methyl-t-diethylaminofluorane instead of t, 0 parts of -methyl-6-dinithylaminofluorane! A color former sheet was obtained in the same manner as [Color former sheet/] except that 0 part of 2-dibenzylamino 6-diethylaminosulfur 2-fluoride and 1.0 part of 2-dibenzylamino 6-diethylaminosulfur were used.

[Coloring agent sheet 3] Co-anilino 3 was used as the coloring agent in [coloring agent sheet 1].
-Methyl-t-diethylaminofluorane 6, except that 6.0 parts of co-anilino 3-methyl-4-N-ethyl-intylaminofluorane was used in place of Q part. A color former sheet was obtained. 3 [Color former sheet Hiromu] As a color former for [Color former sheet 1], Coanilino 3
-Methyl-t-diethylaminofluorane, co-anilino 3-methyl-6-h-ethyl instead of Q moiety -isoitylylaminofluorane! A color former sheet was obtained in the same manner as in [Color former sheet)/) except that part Q and cobenzylamino 6-diethylaminofluorane/, part Q were used.

[Preparation of color developer sheet]

[Developer sheet l] [Preparation of dispersion liquid] 3. Zinc j-t-octylsalicylate l! Part, calcium carbonate (Shiraishi Kogyo, Br1lliant-it,
average particle size 0.2 μ) 120 parts, activated clay 10 parts, zinc oxide 20 parts, sodium hexametaphosphate 1 part and water 200 parts
Using part f, the particles were uniformly dispersed using a sand grinder so that the average particle size was 3 μm to obtain a dispersion (A).

[Adjustment of coating liquid]

Dispersion K<A) 100 parts of 10% PVk-//7 (manufactured by Kuraray) io parts of aqueous solution and 7 parts (as solid content) of carboxy-modified SBR latex (manufactured by Tensei Naugatuck, 5N-707) @l70L, solid content The coating liquid was prepared by adjusting water every time the concentration reached 0%.

[Application of color developer sheet]

This coating liquid was coated on 1097 m2 of base paper using an air knife coater so that the solid content was coated with 097 m2, and dried to obtain a color developer sheet. - [Color developer sheet] 3.! in [Dispersion adjustment] of [Color developer sheet/]! - 3.! in place of l! part of zinc t-octylsalicylate
A developer sheet was obtained in the same manner as in [Developer sheet)/) except that lt part of zinc di-t-dodecylsalicylate was used.

[Developer sheet 3] In [Dispersion adjustment] of [Developer sheet 1], set 3°
Instead of 1 part of zinc t-octylsalicylate! - A developer sheet was obtained in the same manner as [Developer sheet/] except that 75 parts of zinc cyclohexylcyclohexylsalicylate was used.

[Comparison developer sheet l]

In [Dispersion liquid adjustment] of [Developer sheet/], adjust the
3. instead of 75 parts of zinc t-octylsalicylate. j-
A developer sheet was obtained in the same manner as [Developer sheet 1] except that 1 part of zinc bis(α-methylbenzyl]salicylate was used.

The comparative test method described below was conducted on each color former sheet and each color developer sheet obtained as described above.

(1) Hue Test The microcapsule layer of the microcapsule sheet containing a color former was placed on a developer sheet, and a load of zooKy7Cm2 was applied to develop color. After leaving this in a dark place for λμ time, the hue was determined visually and the wavelength was 3ro~7rOn.
The spectral absorption oil N of the chromophore in between is measured, and the absorption maximum on the long wavelength side (λ1) and m degrees at Jl (fresh concentration Do
) was measured.

(2) Light resistance test of coloring material After leaving it in a dark place for several hours obtained in [I], the coloring material was measured using a xenon fetometer (FAL-λ!AX-HC).
The spectral absorption curve of the coloring body was measured after irradiation for a period of time with a model "type)" (manufactured by Suga Test Instruments), and the density at Jl was measured.The spectral absorption curve was measured using a "Hitachi color analyzer model 307" ( (Newly manufactured by Hitachi), and the value indicating light resistance (original resistance value) was calculated using the following formula.

The larger the tatami resistance value after irradiation with the xenon 7 edometer, the better the light resistance of the coloring material.

At the same time, the degree of red discoloration of the colored body was evaluated visually. The results obtained are shown in Table 1.

(Effects of the Invention) As is clear from the results in Table 7, when the color former sheet and color developer sheet according to the examples of the present invention are used, the light resistance of the color former is superior and good compared to the comparative example. It can be seen that a black color is produced.

Claims (1)

[Scope of Claims] In a pressure-sensitive recording sheet that obtains a colored image by a reaction between a nearly colorless electron-donating dye and an electron-accepting color developer, the electron-accepting color developer is represented by the general formula [I]. 1. A pressure-sensitive recording sheet comprising a metal salt of a salicylic acid derivative and, as an electron-donating dye, a fluoran derivative represented by the general formula [II]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼〔I〕 (In the above formula, R_1_1, R_1_2, R_1_3, R_
1_4 represents a hydrogen atom or an alkyl group. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [II] (In the above formula, R_1 and R_2 are independently hydrogen atoms or unsubstituted or halogen atoms having 18 or less carbon atoms, hydroxyl group, cyano group, alkoxy represents an alkyl group substituted with a group, an aryloxy group, a heterocyclic group or an aryl group, a C_5-C_7 cycloalkyl group, or a phenyl group unsubstituted or substituted with an alkyl group, and -NR_1R_2 It may form a 5- to 7-membered ring.)