JPH02273287A - Recording material - Google Patents

Abstract

PURPOSE:To provide a recording material capable of obtaining an image excellent in light fastness and having high developed color density by allowing a specific compound and an electron donating dye precursor to coexist. CONSTITUTION:A recording material is prepared by applying microcapsules containing an electron donating dye precursor and at least three kinds of compounds selected from four kinds of compounds consisting of benzotriazole, hindered piperidine, phosphite and hydroquinone to a support. As benzotriazole, for example, there is 2(2'-hydroxy-5'-methylphenyl)benzotriazole and hindered piperidine is pref. substituted at its N-position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a recording material capable of pressure-sensitive recording or heat-sensitive recording, and particularly to a recording material that has excellent light resistance before recording.

(Prior art) ``For pressure-sensitive recording materials, a colorless electron-donating dye precursor is dissolved in a suitable solvent, and a microcapsule layer containing microcapsules containing the resulting oil is formed on a support. A top paper coated with a color developer layer containing an electron-accepting compound (hereinafter referred to as a color developer) is coated on the other support, and in some cases, a micro-layer paper is coated on one side of the support. A combination of a capsule layer and an inner sheet coated with a color developer layer on the other side, a monosheet type in which the capsules and a color developer are contained on the same side of the support, and There is one in which one of the capsules or the color developer is contained and the other is coated.

These pressure-sensitive recording papers are described, for example, in US Pat. No. 2,505.
No. 470, No. 2,505,489, No. 2.550,4
No. 71, No. 2,730,457, No. 3,418,25
No. 0 and Japanese Patent Publication No. 48-49509.

On the other hand, as a heat-sensitive recording material using microcapsules,
For example, there is Japanese Patent Application No. 59-99490 (please change the number to Japanese Patent Application Laid-Open No. 1983-1991) filed by the present applicant.

Such a heat-sensitive recording material consists of microcapsules whose cores contain a solution of a color former dissolved in an organic solvent, and a color developer, which is the other component that reacts with the color former to form a color, on the same side of a support. This system takes advantage of the fact that the microcapsule wall becomes transparent when heated, and causes the color forming agent and color developer in the heated area to come into contact with each other to form an image.

In this case as well, electron-donating dye precursors are mainly used as color formers, and phenolic compounds,
Organic acids or metal salts thereof, oxybenzoic acid esters, etc. are used.

(Problems to be Solved by the Invention) When a recording material coated with microcapsules containing a solution of an electron-donating dye precursor as described above is exposed to light for a long time, coloration occurs over the entire surface.

In addition, colored recording materials have disadvantages such as poor coloring performance and only low-density recorded images. This phenomenon is remarkable when the electron-donating dye precursor is used dissolved in an organic solvent, but hardly occurs when it is used as a solid dispersion.

As a method for preventing coloration of pressure-sensitive recording materials, it was proposed in Japanese Patent Publication No. 44 (1972) to incorporate an ultraviolet absorber into microcapsules together with an electron-donating dye precursor solution for the purpose of improving the light resistance of colored images on the lower paper. -14380. However, even if only an ultraviolet absorber is used, a sufficient coloring prevention effect cannot be obtained.

As a result of intensive studies to solve the above-mentioned drawbacks, the present inventors have discovered that benzotriazoles, hindered piperidines,
It has been found that when at least three of the four compounds of phosphites and hydroquinones are made to coexist with the electron-donating dye precursor, the light resistance of the electron-donating dye precursor is significantly improved. We have arrived at the present invention.

Therefore, a first object of the present invention is to provide a recording material carrying microcapsules containing an organic solvent solution of an electron-donating dye precursor, which has excellent light resistance and can obtain images with high color density. It is in.

A second object of the invention is to provide a method for improving the lightfastness of a recording material carrying microcapsules containing an organic solvent solution of an electron-donating dye precursor.

(Means for Solving the Problems) The above aspects of the present invention are made from an electron-donating dye precursor and four types of compounds: benzotriazoles, hindered piperidines, piperidines, phosphites, and hydroquinones. This has been achieved by a recording material characterized in that a support supports microcapsules containing at least three compounds selected from the group consisting of:

The electron-donating dye precursor used in the present invention is appropriately selected from known compounds such as triallylmethane compounds, diphenylmethane compounds, xanthine compounds, thiazine compounds, and spiro compounds, or mixtures thereof. can be used.

Specific examples of the electron-donating dye precursors include, for example, JP-A No. 6
It is described in Japanese Patent No. 1-89881.

The choice of electron-donating dye precursor to be used is determined by the use and desired properties of the recording material. Among these, the effect of the present invention is particularly large when triarylmethane-based leuco dyes and fluoran-based leuco dyes having a phthalide structure are used. This is the case when a black thread leuco dye selected from fluorans with
The use of leuco dyes is also highly effective, and it is appropriate that these leuco dyes be used in an amount of 5 to 100% by weight based on the organic solvent.

As the organic solvent used in the present invention, it is preferable to use one with a boiling point of 180°C or higher, since a low-boiling point one will cause evaporation loss during raw storage. It can be appropriately selected and used from among esters, fatty acid amides, alkylated biphenyls, alkylated terphenyls, chlorinated paraffins, alkylated naphthalenes, diarylethanes, etc., and vinyl compounds. Details of these organic solvents are described in, for example, JP-A-63-45084.

It is also possible to use the above organic solvents together or with other organic solvents.

In the present invention, a low boiling point solubilizing agent may be added as an auxiliary solvent to the above organic solvent. Particularly preferred examples of such co-solvents include ethyl acetate, isopropyl acetate, butyl acetate and methylene chloride.

The benzotriazoles to be contained in the microcapsules together with the electron-donating dye precursor can be appropriately selected from known ones, but may be of the general formula (where A is a phenyl group which may have a substituent). and X represents a hydrogen atom, a halogen, or an alkyl group), and particularly compounds represented by H (wherein,
8 represents a hydrogen atom, an alkyl group, or an alkoxycarbonyl group) is preferred.

Specific examples of these preferred compounds are disclosed in, for example, JP-A-63
-7180, among others, 2 (2'
-Hydroxy-5'-methylphenyl)benzotriazole, 2 (2"-hydroxy-5' -ter
t-7'tylphenyl)benzotriazole, 2(2'
Particularly preferred are -hydroxy-3'5'-di-cumylphenyl)benzotriazole, 2'-hydroxy-5'-octylphenyl)benzotriazole, and the like.

The hindered piperidines used in the present invention can be appropriately selected from known compounds, but piperidine derivatives having the following partial structure are preferred, and the solubility in organic solvents when encapsulated in microcapsules From the viewpoint of preventing reaction with isocyanate compounds which are preferred as capsule wall forming materials, it is particularly preferable that the N-position is substituted.These are described in JP-A-63-51174, but preferred ones are listed below. Then, x″″′ n// \′ / etc. can be mentioned.

The phosphite used in the present invention can be appropriately selected from among known antioxidants, but (in the formula, R is a hydrogen atom or an alkyl group) is particularly preferred, and specific examples include R3. can be mentioned.

Hydroquinones used in the present invention are, for example, US Pat. No. 2,360,290, US Pat. No. 2,418.613,
2,700.453, 2.701,197, 2.728,659, 2,732,300
No. 2,735゜765, No. 3,982,94
No. 4, No. 4゜430.425, No. 2,710,8
No. 01, No. 2.816,028 and British Patent No. 1.
Among these, preferred in the present invention are those described in No. 363.921, etc. (wherein R3 and R4 are alkyl groups), particularly those in which R3 and R4 are C4 to C2° alkyl groups. is preferred.

In the present invention, at least three compounds are selected from the group consisting of the above-mentioned four types of compounds: benzotriazoles, hindered piperidines, phosphites, and hydroquinones. In this case, the various compounds used may be used alone or in combination of two or more.

The minimum mixing ratio of the three types is 5% to 30% by weight, preferably 1011% to 20MN%, and the maximum is 30%! if% to 90% by weight, preferably 40% to 80% by weight. The total amount of these is 10 to 100% by weight, preferably 20 to 80% by weight based on the organic solvent.
used in

As the color developer that develops color upon contact with the electron-donating dye precursor, a phenol compound, an organic acid or a metal salt thereof, an oxybenzoic acid ester, etc. are used. Among these color developers, the melting point is 50°C to 250°C1, especially 60°C to
Phenols and organic acids that are sparingly soluble in water at 200°C are preferred.

Examples of phenolic compounds include 4.4°-isobropylidene diphenol (bisphenol A), P-te
rt-butylphenol, 2.4-dinitrophenol, 3,4-dichlorophenol, 4.4°-methylene-
bis(2,6-tert-7'tylphenol),
p-phenylphenol, 4,4-dichlorohexylidene diphenol, 2,2'-methylenebis(4-tert
-butylphenol), 2,2'-methylenebis(α
-phenyl-P-cresol)thiodiphenol, 4.
4°-thiobis(6-tert-butyl-m-cresol), sulfonyldiphenol, 1.1-bis(4-hydroxyphenyl)-n-dodecane, 4.4-bis(4
-Hydroxyphenyl)-1-bencunonic acid ethyl ester, p-tert-7' tylphinol-formalin condensate, p-phenylphenol-formalin condensate, and the like.

Examples of organic acids or metal salts thereof include 3-tert-butylsalicylic acid, 3.5-tert-butylsalicylic acid, 5-α-methylbenzylsalicylic acid, 3.5-di-α
-Methylbenzylsalicylic acid, 3-tert-octylsalicylic acid, 5-α.

γ-dimethyl-α-phenyl-T-phenylpropylsalicylic acid, etc., and its zinc acid, lead salt, aluminum salt, magnesium salt, nickel salt, etc. are useful.

Examples of oxybenzoic acid esters include ethyl p-oxybenzoate, butyl p-oxybenzoate, heptyl p-oxybenzoate, benzyl p-oxybenzoate, and the like.

In particular, the above color developer is dissolved in an organic solvent that is sparingly soluble or insoluble in water, and then mixed with an aqueous phase containing a surfactant and a water-soluble polymer as a protective colloid to form an emulsified dispersion. When used in , the recording layer can be substantially transparent.

The organic solvent used in this case can be appropriately selected from high boiling point oils. In addition to esters, preferred oils include those of the following general formulas (I) to (III).
) and triallylmethane (e.g.
tritolylmethane, tolyldiphenylmethane), terphenyl compounds (e.g. terphenyl), alkyl compounds (e.g. eva, terphenyl), alkylated diphenyl ethers (e.g. propyl diphenyl ether),
Examples include hydrogenated terphenyl (eg, hexahydroterphenyl), diphenyl ether, and the like.

In the present invention, it is preferable to use esters among these from the viewpoint of emulsion stability of the emulsified dispersion.

In the formula, R1 is hydrogen or an alkyl group having 1 to 18 carbon atoms, R
t represents an alkyl group having 1 to 18 carbon atoms eP's q
' represents an integer from 1 to 4, and the total number of alkyl groups is 4 or less.

Incidentally, the alkyl groups for R' and Rf are preferably alkyl groups having 1 to 8 carbon atoms.

(n) In the formula, R represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, R4 represents an alkyl group having 1 to 12 carbon atoms, and n is 1
Or represents 2.

p t and q R represent an integer of 1 to 4. In the case of n-1, the total number of alkyl groups is 4 or less, and n-1
When 2, the total number of alkyl groups is 6 or less.

(III) In the formula, R5 and Rh represent a hydrogen atom or the same or different alkyl groups having 1 to 18 carbon atoms.

m represents an integer of 1 to 13, 11P''%Q3 represents an integer of 1 to 3, and the total number of alkyl groups is 3 or less.

In addition, the alkyl group of R1 and Rh is particularly preferably an alkyl group having 2 to 4 carbon atoms.

Examples of the compound represented by formula (1) include dimethylnaphthalene, diethylnaphthalene, diisopropylnaphthalene, and the like.

Examples of the compound represented by formula (II) include dimethylbiphenyl, diethylbiphenyl, diisopropylbiphenyl, and diisobutylbiphenyl.

Examples of compounds represented by formula (III) include 1-methyl-1-dimethylphenyl-1-phenylmethane, 1-ethyl-1-dimethylphenyl-1-phenylmethane, and 1-phenylmethane.
-propyl-1-dimethylphenyl-1-phenylmethane.

Examples of esters include phosphate esters (for example, triphenyl phosphate, tricresyl phosphate, butyl phosphate, octyl phosphate, cresyl diphenyl phosphate), phthalate esters (
Dibutyl phthalate, 2-ethylhexyl phthalate, ethyl phthalate, octyl phthalate, butylbenzyl phthalate) dioctyl tetrahydrophthalate, benzoic acid ester (ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate, benzoic acid) benzyl acid), abietate ester (ethyl abietate, benzyl abietate), dioctyl adipate, isodecyl succinate, dioctyl azelaate, oxalate ester (dibutyl chelate, dipentyl oxalate), diethyl malonate, maleate ester ( dimethyl maleate, diethyl maleate, dibutyl maleate), tributyl citrate, sorbate esters (methyl sorbate, ethyl sorbate, butyl sorbate), sebacate esters (dibutyl sebacate, dioctyl sebacate), ethylene glycol ester (formic acid monoesters and diesters, butyric acid monoesters and diesters, lauric acid monoesters and diesters, valmitic acid monoesters and diesters, stearic acid monoesters and diesters, oleic acid monoesters and diesters),
Examples include triacetin, diethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate, boric acid esters (tributyl borate, tripentyl borate), and the like. Among these, when tricresyl phosphate is used alone or in combination, the emulsion dispersion stability of the color developer is particularly good, and therefore it is preferable.

It is also possible to use the above oils together or with other oils.

The recording material of the present invention can be used for pressure-sensitive recording, heat-sensitive recording, and other recording materials in which microcapsules containing a solution of an electron-donating dye precursor are supported on a support. The most useful application of the present invention is a recording material such as heat-sensitive recording paper (i.e., a recording material with microcapsules supported on its surface).In pressure-sensitive recording materials, the microcapsules are coated on the back surface, so they are not exposed directly to light. Coloring is unlikely to occur.Also, even if it is colored, it will not cause any problems in the case of heat-sensitive recording materials because it is on the back side.6 When the present invention is used in a pressure-sensitive recording sheet, the microcapsules can be obtained by a normal microencapsulation method. For example, U.S. Pat. No. 3,429,827, U.S. Pat.
Interfacial polymerization methods such as No. 7 and No. 1,091,078, U.S. Patent Nos. 2,969,330 and 3,660,304
No. 3,726,804, No. 3,796.66
Internal polymerization method such as No. 9, Japanese Patent Publication No. 37-14327, No. 3
External polymerization methods such as No. 7-12380 and No. 48-4717, U.S. Pat.
No. 456, No. 2,712,507, etc., the coacelbasigon method, British Patent No. 931,148, U.S. Patent No. 3,173,875, etc. Encapsulation methods such as the method used can be applied.

The wall of the microcapsule used in the heat-sensitive recording material is preferably one that allows at least one of the color forming agent and the color developer to pass through when heated. Specific examples of the polymeric substance constituting such a preferable capsule wall include polyurethane and polyurea. , polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer, styrene-acrylate copolymer, and the like. Among these, those having a glass transition temperature of 60 to 200°C are preferred.

It is particularly preferable to use a microcapsule method by polymerizing glue actant from inside the oil capsule to form the above-mentioned microcapsule wall.This method allows for the production of particles with uniform particle size and excellent shelf life in a short period of time. Microcapsules can be obtained through which a heat-sensitive recording material can be obtained.

This method and specific examples of compounds are described in U.S. Pat.
, No. 726.804 and No. 3,796.669.

In the case of heat-sensitive recording materials, the coating amount of microcapsules is from 1 to 10 g/poly, preferably from 3 to 7 g/% in terms of dry weight. This microcapsule can be used in top paper, middle paper, and monosheet types.

In heat-sensitive recording materials, the microcapsules and the color developer are provided on the same side of the support.

Other materials such as binders are described in the aforementioned Japanese Patent Application No. 59-99490, and can be similarly used in the present invention.

Example 1 8 parts of color developer (a), 4 parts of (b) and 30 parts of (c) represented by the following structural formula of ゜A were mixed with 2 parts of 1-phenyl-1-xylylethane.
．． 0 parts, dibutyl phthalate 6.0 parts and ethyl acetate 30 parts
It was dissolved in parts. The obtained developer solution was mixed and emulsified into an aqueous solution of 100 parts of an 8% polyvinyl alcohol aqueous solution, 150 parts of water, and 0.5 parts of sodium dodecylbenzenesulfonate to form an emulsion with a particle size of 0.5 μm. A dispersion was obtained.

Color developer (with) Color developer (C) Color developer (a) , / / / /- As the electron-donating dye precursor of microcapsule A, the following compound (CIBA
Pergascript Red! -6-8)
50 parts (a) (Sumisorb 340 Product name manufactured by Sumitomo Chemical ■) tcmH+y 18 parts (b) (Tlnuvin 622 LD Product name manufactured by Ciba Geigy ■ Diethyl maleate 30 parts 1-phenyl-1-xylylethane 25 parts Ethyl acetate
15 parts 6 parts (c) (Sumtlizer TTP-R: manufactured by Sumitomo Kagaku ■, trade name) Takene) 11ON (manufactured by Takeda Pharmaceutical Company Limited (trade name)) 60 parts were mixed, and 100 parts of an 8% by weight aqueous solution of polyvinyl alcohol and distilled water were mixed. After adding it to an aqueous solution consisting of 40 parts, it was emulsified and dispersed at 20°C to obtain an emulsified dispersion with an average particle size of lμ.Next,
The obtained emulsion was continuously stirred at 40° C. for 3 hours to obtain microcapsule liquid A.

Transfer 11] Shiso Co., Ltd. 1 Silica-modified polyvinyl alcohol (PVA manufactured by Kuraray)
R2105) 10% by weight liquid 10 parts Colloidal silica (Snowtex 30 manufactured by Nissan Chemical ■) 30
Parts%Liquid 5 partsZinc stearate (
Hydrin 2-7) manufactured by Middle East Oil ■ 30-weight liquid
0.42 parts paraffin wax (Middle East oil)
Hydrin P-7) 30% liquid
0.42 parts were mixed to obtain a protective layer liquid A for transparent preservation. A mixed solution of 5.0 parts of Capsule Liquid A and 10.0 parts of Color Developer Dispersion A was applied so that the dry coating amount was 6 g/rrf.

Next, the retaining rIIN solution A was applied using a wire bar so that the dry coating amount was 2 g/rd, and then dried in an open setting at 50''C to obtain a heat-sensitive recording sheet.

A fluorescent lamp of 32,000 lux was applied to the obtained recording sheet.
After 6 hours of irradiation, no change was observed in the appearance. The yellow density was measured using a Macbeth densitometer (RD-918) and the fog density was evaluated to be 0.1.
9, which was confirmed to be the same as before the fluorescent lamp irradiation.

Example 2 A heat-sensitive recording sheet was prepared in the same manner as in Example 1, except that Sumillzer TTP-R was not used as an antioxidant, and the light resistance test was conducted in the same manner as in Example 1. , the yellow density is 0°20,
Almost no change could be observed with the naked eye.

Example 3 Tinu+win 622 LD as ultraviolet absorber
A heat-sensitive recording sheet was prepared in exactly the same manner as in Example 1, except that the film was not used, and the light resistance was tested in the same manner as in Example 1, and the same results as in Example 2 were obtained. .

Comparative Example 1゜Benzotriazole UV absorber Sua+1sorb
A heat-sensitive recording sheet was prepared in the same manner as in Example 1 except that 340 and the hydroquinone reducing agent were not used, and the light resistance was tested in the same manner as in Example 1. The yellow density was 0.30. can be,
Discoloration to brown was observed with the naked eye.

Comparative Example 2゜Benzotriazole UV absorber Sus+1sorb
340 and hydroquinone reducing agent hindered piperidine ultraviolet absorber Tinusin
622 LD and phosphite antioxidant Sumil
A heat-sensitive recording sheet was prepared in exactly the same manner as in Example 1, except that the IzerTTP-R was not used, and the light resistance was tested in the same manner as in Example 1. The yellow density was 0.37, and it was However, it was noticed that the color had changed to reddish brown.

Comparative Example 3 Hydroquinone-based reducing agent Hindered piperidine-based ultraviolet absorber Tjnuvin
622 LD and phosphite antioxidant Sumil
A heat-sensitive recording sheet was prepared in exactly the same manner as in Example 1, except that the Izer↑TP-R was not used, and when the light resistance was tested in the same manner as in Example 1, the yellow density was 0.33. It was observed that the color changed to reddish brown even with the naked eye.

Example 4 [Preparation of upper paper for pressure-sensitive recording sheet] 5 parts of a partial sodium salt of polyvinylbenzenesulfonic acid (manufactured by National Starch Co., Ltd., VER3A, TL500, average molecular weight 500.000) was heated at about 80"C. It was added to 95 parts of water with stirring, dissolved over about 30 minutes, and then cooled.The pH of the aqueous solution was 2 to 3, and a 20% by weight aqueous sodium hydroxide solution was added to adjust the pH to 4.0. did.

On the other hand, 2.5% by weight of crystal violet lactone,
1.0% by weight benzoylleucomethylene blue, 2%
(a) 1% by weight of a hindered piperidine ultraviolet absorber (Sumisorb 200: trade name manufactured by Sumitomo Chemical ■) 2% 2.5-di-tert-butyl (MARK LA-63: trade name manufactured by Adeka Argus ■) 100 parts of diisopropylnaphthalene in which hydroquinone and 1% by weight were dissolved were emulsified and dispersed in 100 parts of a 5% by weight aqueous solution of the partial sodium salt of polyvinylbenzenesulfonic acid to obtain an emulsion having a particle size of 4.5 μm in average diameter. Ta. Separately, 6 parts of melamine,
11 parts of a 37% by weight formaldehyde aqueous solution and 30 parts of water were heated and stirred at 60°C, and after 30 minutes, a transparent mixture of melamine, formaldehyde and melamine-formaldehyde initial condensate was obtained. The pH of this mixed aqueous solution was 6-8. Hereinafter, this mixed aqueous solution of melamine, formaldehyde, and melamine-formaldehyde initial condensate will be referred to as an initial condensate solution. Add and mix the initial condensate solution obtained by the above method to the above emulsion, and add 3.6% by weight while stirring.
The pH was adjusted to 6.0 with a hydrochloric acid solution, the temperature of the solution was raised to 65°C, and stirring was continued for 360 minutes. The capsule liquid was cooled to room temperature and adjusted to pH 9.0 with 20% by weight sodium hydroxide.

To this capsule dispersion, 200 parts of a 10% by weight polyvinyl alcohol aqueous solution and 50 parts of starch particles were added, and water was added to adjust the solid content concentration to 20% by weight.

This coating solution was applied to 50 g/rrt base paper using an air knife coater so that the solid content was 5 g/%.
It was dried to obtain a top sheet for pressure-sensitive recording paper.

The obtained upper paper was tested for light resistance in the same manner as in Example 1, except that the cyan density was measured instead of the yellow density. fi!! was found to be 0.15 and the same as before the light irradiation.

Example 5゜Phosphite antioxidant Sumi used in Example 4
A top sheet for pressure-sensitive recording paper was prepared in exactly the same manner as in Example 4, except that the lizer TTP-R was not used.
When a light fastness test was conducted in the same manner as above, the cyan density was 0.18, and almost no change was observed with the naked eye.

Comparative Example 4゜5untsorb 200. MARK LA-63,
2,5-di-tert-thylhydroquinone Sumil
A top sheet for pressure-sensitive recording paper was prepared in exactly the same manner as in Example 4, except that Izer TTP-R was used, and a light fastness test was conducted in the same manner as in Example 4, and the cyan density was 0. ．． 29, and it was observed that the color changed to bluish brown.

The results of the above Examples and Comparative Examples are summarized in Table 1.

The results in Table 1 demonstrate that the recording material of the invention has significantly improved light fastness, and it is clear that this does not result in a decrease in recording density.

Patent applicant: Fuji Photo Film Co., Ltd. Reason Man

Claims (1)

[Claims] Supports microcapsules containing an electron-donating dye precursor and at least three compounds selected from the group consisting of four compounds: benzotriazoles, hindered piperidines, phosphites, and hydroquinones. A recording material characterized by being carried on the body.