JPS5887088A - Heat-sensitive recording material - Google Patents

Abstract

PURPOSE:To obtain a heat-sensitive recording material having sufficient coloring density and sensitivity and sufficient fastness of colored pictures and free of lowering with time of coloring sensitivity and also of fogging phenomenon by using an electron donative compound, an electron receiving compound, and a specific phenolic derivative. CONSTITUTION:For example, an electron donative colorless dye (e.g., 2-anilino- 3-methyl-6-diethylamino fluoran, etc.) and an electron receiving compound (e.g., bisphenol A, etc.) are separately dispersed in a 1-10wt% water-soluble high- molecular compound (e.g., PVA, etc.) solution by means of a ball mill, sand mill, etc., and also a phenolic derivative (e.g., 4-cumylphenylbenzyl ether, etc.) of the formula (R is an alkyl or aralkyl and Y is an aralkyl) is dispersed likewise in a water-soluble high molecular compound solution. Then, the three dispersions are mixed together, further mixed with an inorganic pigment (e.g., kaolin, talc, etc.), and then coated on a base paper to obtain an objective recording material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive recording material, and particularly to a heat-sensitive recording material with improved color development.

Heat-sensitive recording materials using deuteron-donating colorless dyes and electron-accepting compounds are published in Japanese Patent Publication Shoguj-/≠037 and Japanese Patent Publication Sho≠3.
-11/10 etc. The minimum performance that such a heat-sensitive recording material should have is (1) -/- sufficient color development degree and color development sensitivity, and (2) no capri (color development phenomenon during storage before use). ,(
3) The fastness of the coloring material after coloring is sufficient, etc. However, at present, no product has been obtained that satisfies these requirements.

Especially in recent years, as thermal recording systems have become more relevant,
) has been extensively researched.

The method is to fuse the electron-accepting compound itself to 60%.
The temperature may be increased from 700 °C to 700 °C. However, it is difficult to control the melting point of phenolic compounds, which are currently the most widely used electron-accepting compounds, and the phenolic compounds themselves are expensive and impractical.

Other methods include using an organic acid and a phenolic compound together as an electron-accepting substance in the Tokko Sho Geter/77'ir and the Tokko Sho J/-J RijtV, or using a compound having an alcoholic hydroxyl group. It has been described that polyvalent metal salts of It is also described that a copolymer of ethyl cellulose and maleic anhydride is used.

Tokko Akira again! The addition of waxes is described in Tata No. 273 and Japanese Patent Publication No. 23/-23.

Furthermore, Tokukai Sho ≠ ter 3 μr guko issue, Tokukai Sho guar//rijj≠ issue, Tokukai Sho! 0-7g No. 7353, JP-A-Shota 2-
Thioacetanilide, phthalonitrile, etc. or λ, 3-
It is described that a thermofusible substance such as di-m-t IJ glutan, ≠ p/-dimethylbiphenyl, or a carboxylic acid ester such as dimethyl inphthalate, diphenyl phthalate, dimethyl terephthalate, etc. is added as a sensitizer. has been done.

However, the thermal recording materials produced using these methods are insufficient in terms of color density and color sensitivity.

Therefore, an object of the present invention is to provide a heat-sensitive recording material which has sufficient color density and color impression IW and satisfies other requirements.

The object of the present invention has been achieved by a heat-sensitive recording material characterized by containing a colorless dyestuff-donating dye, a playko-accepting dye, and a phenol derivative represented by the following general formula (I).

In the above general formula (1), the alkyl group represented by R preferably has carbon M/-20, and carbon B/-10.
is more preferable.

The aralkyl group represented by R preferably has 7 to 2θ carbon atoms, and particularly preferred examples include benzyl group,
-rogen-substituted benzyl group, alkyl-substituted benzyl group,
Examples include naphthylmethyl group.

In the above general formula (I), the aralkyl group represented by Y preferably has 7 to 20 carbon atoms, and has 7 to 1/1 carbon atoms.
are more preferable, examples of which include hahenzyl group, α
-phenethyl group, β-phenethyl group, cumyl group, etc.

In the phenol derivative represented by the general formula (I) according to the present invention, the substituent represented by Y is for the OIL group,
Although it may be substituted at any of the ortho, meta and para positions, para substitution is particularly preferred.

Among the above phenol derivatives, ≠00C~/jo Oc
It is preferable to have a melting point of jθ0C~/, z
Those having a melting point of o 0c are preferred.

The heat-sensitive recording material containing the phenolic enzyme conductor represented by the general formula (Il) according to the present invention has sufficient color density and color sensitivity, and furthermore, the color sensitivity decreases over time with 'fx <,
There is no capri, and the hardness of the color body after color development is sufficient.

Next, specific examples of the phenol derivative according to the present invention will be shown, but the present invention is not limited to these.

(1) ≠-cumylphenyl be/dyl ether (2)
4t-cumylphenyl-p-chlorobenzyl ether (3) 4'-cumylphenyl-p-methylbenzyl ether (4) ≠-benzylphenylbenzyl ether (5
) Hiro-pendylphenyl-p-chlorobenzyl ether (6) ≠-benzylphenyl-p-methylbenzyl ether (7) ! -cumylphenylnaphthyl methyl ether Examples of the electron-donating colorless dyes used in the present invention include triarylmethane compounds, diphenylmethane compounds,
Xanthene-based compounds, thiazine-based compounds, spiropyran-based compounds, etc. are used.To give some examples of these, triaryl 6-methane-based compounds include 3,3-bis(p-)methylaminophenyl 11- Dimethylaminophthalide (i.e. crystal violet lactone), 3.3-bis(p-dimethylaminophenyl)phthalide, 3(p-dimethylaminophenyl)-3-(/,3-dimethylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-J-(2-methylindol-3-yl)phthalide, etc., and as a diphenylmethane compound, ≠ 4t/-his-dimethylaminobenzhydrin benzyl ether, N- Halophenyl-leucoauramine, N-J, ≠, t-)dichlorophenylleucoauramine, etc., and xanthine compounds include rhodamine-B-anilinolactam, rhodamine (p-nitroanilino)lactam, rhodamine B (p- chloroanilino)
Lactam, λ-dibenzylamino-t-diethylaminofluorane, no-anilino-6-diethylaminofluorane, co-anilino-3-methyl-6-dinithylaminofluorane, 2-anilino-3-methyl-t-cyclohegysylmethylamino Fluoran, 2-〇-chloroanilino-t-diethylaminofluorane, l-m-chloroanilino-6-diethylaminofluorane, -~(j, 4
t-dichloroanilino)-6-diethylaminofluorane, λ-octylamino-3-diethylaminofluorane,! -dihexylamino-t-diethylaminofluorane, co-m-trifluoromethylanilino-6-diethylaminofluorane, coptylamino-3-chloro-
6-diethylaminofluorane, -monoethoxyethylamino-3-chloro-4-diethylaminofluorane, co-anilino-3-chloro-t-diethylaminofluorane, λ-diphenylamino-t-diethylaminofluorane, λ-anilino-3-methyl- 6-cy7enylaminofluorane, λ-phenyl-t-diethylaminofluorane, etc. Thiazine compounds include benzoylleucomethylene blue, p-nitropenzylleucomethylene flu, etc., and spiro compounds include 3 −
Methyl subi "cordinaphthopyran, 3-ethyl-spiro-dinaphthopyran, J,J'-cyclospiro-dinaphthopyran, 3-benzylspiro-dinaphthopyran,
Examples thereof include 3-methyl-naphtho-(3-methoxy-benzo)spiropyran and 3-propyl-ruth birosehenzobilan. These may be used alone or in combination.

Examples of electron-accepting compounds include phenolic compounds,
Organic acids or their gold maple salts, oquine benzoate esters,
In particular, phenol compounds have a melting point close to the desired recording temperature, so there is no need to use a particularly low melting point compound, but they are preferably used because their t can be small. /11039, Special Public Sho J/-29
It is described in detail in No. 130, etc. Specifically, ≠−
Tertiary butylphenol, gouphenylphenol, goohydroxydiphenoxide, α-naphthol,
β-naphthol, methyl-t-hydroxybenzoate, λ,2'-dihydroxybiphenyl, 2. +2-bis(≠-hydroxyphenyl)-ta-propane (bisphenol Al, 4Z, 4(/-inpropylidene bis(+2-methylphenol), /l/-
Examples thereof include bis-(3-chloro-μm hydroxyphenyl)cyclohexane, /, l-bis-(3-chloro-guhydroxyphenyl)-11ethylphthane, +, +'-secondary isoftyrite/diphenol, and the like.

The heat-sensitive recording material according to the VC of the present invention contains one or more phenol derivatives represented by the general formula (1), and a specific example of the method for producing the same is described below.

The most common method for producing heat-sensitive recording materials is to separately prepare an electron-donating colorless dye as mentioned above and an electron-accepting compound in a 7 to 70% by weight aqueous molecular solution, using a whole mill, After dispersing and mixing using a sand mill or other means, inorganic pigments such as kaolin, talc, and calcium carbonate are added to prepare the entire coating solution.Additionally, paraffin wax emulsion, latex thread binder, sensitivity improver, and gold stone are added as needed. Can cool UV absorbers, etc.

Coating fluids are most commonly applied onto base paper.

Generally, the coating amount is ↓, and the solid content is λ~/097m2
The F limit is determined by the density at the time of color development by heating, and the upper limit is determined mainly by economic constraints.

Examples will be shown below, but the present invention is not limited only to these examples.

Actual example (1) Preparation of sample l-≠ The electrodynamic colorless dye ty shown in Table 7 was soaked in a ball mill for one day and a night with 5% polyvinyl alcohol (Ken system: 9'7%, concentration: lOθO) aqueous solution soy. did. On the other hand, similarly, the deuteron-accepting compounds (phenols) shown in Table 1, 2θg were dissolved in j% polyvinyl alcohol aqueous @, :z
After dispersing in a ball mill for a day and a night together with oooy, and further dispersing in a ball mill for a day and a night with the phenol inducer shown in Table 1 and a 20-strength polyvinyl alcohol water bath solution, after mixing these three glaze dispersions. Kaolin (Jossia kaolin) 20y was separated by surface and well dispersed, and a coating liquid was prepared by adding Sanihalafin wax emulsion jθ% dispersion (medium thread oil cellosol #≠, zr) and rg.

The coating liquid was applied onto a base paper having a surface area of 1 tsubo of soy/m2 so that the solid content coating amount was A g/7n''.
°C'''c 1 minute dry S winning pressure A OkgW/cm-
(: /(= Apply the bar calendar and separate the coated paper. The coated paper is heated by facsimile with energy key - 3j m J
/ The color was developed by heating at t32, and the degree of color development was determined.

The results are shown in Table 1.

(2) A similar test was conducted using the exact same formulation as that used to create comparative sample/~λ sample/~j, but replacing only the phenol visiting body with a compound other than the present invention shown in Table 1. Ta.

The results are also shown in the first episode.

It can be seen from Table 1 that the recording material according to the invention clearly has a sensitivity of 1.

The birth rate of Capri in Table 7 is 0. If it exceeds /3, the product value will be significantly reduced.

From this point of view as well, it has been found that the thermosensitive compound of the present invention provides extremely excellent thermal sensitivity.

Claims (1)

[Claims] A heat-sensitive recording material characterized by containing a turtle-donating colorless dye, an electron-accepting compound, and a phenol derivative represented by the following general formula (I), where R is an alkyl group or an aralkyl group, Y represents an aralkyl group.