JPH03114775A - Thermal recording material - Google Patents

Abstract

PURPOSE:To improve a high-speed recording suitability by a method wherein a thermal recording layer containing a colorless or light-colored basic dye, a color developer, and a hot melt substance shown by a specific general formula is provided on a supporter to form a thermal recording material. CONSTITUTION:A colorless or light-colored basic dye, a color developer, and a hot melt substance shown by a formula I (R1, R2 are 1-4 C alkylene, alkynylene, or the like; X, Y, X1, Y1 represent H, alkyl, acyl, halogen atom, or the like; and (n) represents an integer 2-4) are dispersed together or separately in a dispersion medium, such as water, by a stirring and grinding machine, such as a ball mill and an attritor to prepare a coating liquid. This coating liquid is applied on a supporter, such as paper or a plastic film, and dried to form a thermal recording layer thereon. In this manner, a thermal recording material is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a heat-sensitive recording medium, and particularly to a heat-sensitive recording medium that is free from background fog and is suitable for high-speed recording.

``Prior Art'' Conventionally, heat-sensitive recording materials utilize a coloring reaction between a colorless or light-colored basic dye and an organic or inorganic coloring agent to obtain a recorded image by bringing both coloring substances into contact with each other using heat. well known. Recently, with remarkable progress in thermal recording methods, thermal faxes and the like have become capable of high-speed printing, and it has become possible to record a standard A4 size original in 10 seconds or less. With the speed increase in the hardware field, there is a demand for heat-sensitive recording bodies that are excellent in suitability for high-speed recording.

As a means to improve the color development sensitivity of heat-sensitive recording materials, a thermofusible substance with a lower melting point than a basic dye or coloring agent is added to the recording layer, and the basic dye is absorbed by the melted thermofusible substance first. A widely known method is to lower the temperature at which color development starts by dissolving a coloring agent (Japanese Patent Application Laid-Open No. 49-34842, Japanese Patent Application Laid-open No. 53-39139, etc.). However, it is generally difficult to make one type of heat-fusible substance have the property of dissolving both a basic dye and a coloring agent, and even if a heat-fusible substance has such properties, Basic dye, coloring agent,
The melting point decrease due to the eutectic phenomenon of the three-way thermofusible substance causes the temperature at which color development starts to drop excessively, resulting in the disadvantage that color fogging occurs and the whiteness of the recording layer is significantly reduced.

``Problems to be Solved by the Invention'' The present invention provides thermal recording that has sufficient color development sensitivity and color density, is suitable for high-speed recording, and does not cause background fogging even when forcedly stored under high temperature or high humidity conditions. The purpose is to provide the body.

"Means for Solving the Problem" The present invention provides a heat-sensitive recording layer containing a colorless or light-colored basic dye and a coloring agent that changes color when it comes into contact with the basic dye on a support. The present invention has been completed by discovering that this object can be solved extremely efficiently by containing at least one type of thermofusible substance represented by the following general formula [■] in the recording layer of a heat-sensitive recording material. I ended up doing it.

[In the formula, R,, R2 may be the same or different, and represent an optionally substituted alkylene, alkenylene, or alkynylene group having 1 to 4 carbon atoms, and X, Y, X,
Y may be the same or different, and represents a hydrogen atom, an alkyl group, an acyl group, a halogen atom, an alkoxyl group, an alkoxycarbonyl group, an aryl group, an aryloxycarbonyl group, a substituted or unsubstituted amino group, or a carbamoyl group. . Furthermore, x, yx, and y may be bonded to each other to form a cyclization. Furthermore, n represents an integer of 2 to 4. ] "Function" The present invention has extremely excellent coloring sensitivity and coloring density by using a thermofusible substance represented by formula (1), and furthermore, it has excellent coloring sensitivity and coloring density, and also It is possible to obtain a heat-sensitive recording material that does not cause background fogging even when stored. Specific examples of such compounds include 1,2-bis(benzyloxy)ethane, 12-bis(4-methylbenzyl), oxy)ethane, ■, 2-bis(3-methylbenzyl, t-oxy)ethane, 1.2-bis(4-chlorohensyloxy)ethane, 1.2-bis(3,4-dimethylbenzyloxy)ethane , ■, 2-bis(2-(4-methylphenyl)ethoxy)ethane, 1.2-bis(2-(
3,4-dimethylphenyl)ethoxy)ethane, 1,2
-bis(4-(4-methylphenyl)butoxy)ethane, 1-(4-methylhensyloxy)-2-(4-methoxyhensyloxy)ethane, 1,3-bis(hensyloxy)propane, 13- Bis(4-methylhensyloxy)propane, 1,4-bis(hensyloxy)butane, 1,4-bis(4-methylhensyloxy)butane, 1,2-bis(2-(phenyl)vinyloxy)ethane , ■, 2-bis(3(phenyl)flobenyloxy)ethane, 12-bis(2-(phenyl)ethynyloxy)ethane, 1,2-bis(4-acetylhensyloxy)ethane, 1,2-bis( 4-acetylbenzyloxy)ethane, ■, 2-bis(4-propionylhensyloxy)ethane, 1,2-bis(4methoxycarbonylbenzyloxy)ethane, 1,2-bis(4-ethoxycarbonylbenzyloxy) Ethane, 1,2-bis(4
-phenylbenzyloxy)ethane, ■, 2-bis(4
-(ptolyl)benzyloxy)ethane, 1,2-bis(4-(m-1-lyl)hensyloxy)ethane, 12
-bis(l-(phenyloxycarbonyl)hensyloxy)ethane, 1,2-bis(4-(p-anilino)hensyloxy)Xtane, 1,2bis(4-(m-anilino)hensyloxy)ethane, 1, 2-bis(4-(
p-N-methylanilino)hensyloxy)ethane, 1
．． 2-his(4-(p-N,N-dimethylanilino)hensyloxy)ethane, 1,2-bis(4-carbamoylhensyloxy)ethane, and the like. Of course, the compounds are not limited to these compounds, and two or more types can be used in combination.

These compounds can also be used in combination with other thermofusible substances as long as they do not inhibit the desired effects of the present invention, such as stearamide, methylene bisamide stearate, oleic acid amide, balmitic acid amide, Fatty acid amides such as coconut fatty acid amide, 2,2'-methylenebis(
4-methyl 6 tert-butylphenol), 1,
1.3-1-Lis(2-methyl-4-hydroxy-5-
Hindered phenofurs such as tertbutylphenyl)butane, 1,2-bis(phenoxy)ethane, 1°2-bis(4-methylphenoxy)ethane, 12-bis(3-
methylphenoxy)ethane, 2-naphthyl hensyl ether, hensyl-4-methylthiophenyl ether, 4-
Chlorhensyl 4'-methylthiophenyl ether, 4
-Methylhensyl-4'-methylthiophenyl ether and other ethers, dihenzyl terephthalate, and (2) hydroxy-2-naphthoic acid phenyl ester and other esters. Of course, it is not limited to these.

There are various types of colorless or light-colored basic dyes constituting the recording layer in the heat-sensitive recording material of the present invention, and the following are exemplified. 3,3-bis(p dimethylaminophenyl)-6-dimethylaminophthalide, 3,3-bis(p
-dimethylaminophenyl) phthalide, 3-(p-dimethylaminophenyl)-3-(1,2-dimethylindol-3-yl) phthalide, 3-(p-dimethylaminophenyl)-3-(2-methylindole- 3yl)phthalide, 3,3-bis(12-dimethylindole-3-
yl)-5-dimethylaminophthalide, 3,3-bis(
12-dimethylindol-3-yl)-6-dimethylaminophthalide, 3,3-bis(9-ethylhydradur-3-yl)-6-dimethylaminophthalide, 33-bis(2-phenylindole-3 -yl) 6-dimethylaminophthalide, 3-p-dimethylaminophenyl-1
i-realylmethane dyes such as -(1-methylpyrrol-3-yl)-6-dimethylaminophthalide, 4.4'-
Bis-dimethylaminohenzhydrylhenzyl ether, N-halophenyl-leucoolamine, N-245-1
~Diphenylmethane dyes such as dichlorophenyl leuco auramine, thiazine dyes such as benzoyl leucomethylene blue, p-nitrohendiyl leucomethylene blue, 3-methyl-spirodinaphthopyran, 3-ethyl-
Spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3-benzyl-spiro-dinaphthopyran,
Spiro dyes such as 3-methyl-naphtho(6'-methoxyhenzo)spiropyran, 3-probyl-spirodihensohyran, rhodamine-B-anilinolactam, rhodamine(p-nitroanilino)lactam, rhodamine (0-
Lactam dyes such as chloroanilino)lactam, 3-dimethylamino 7-methoxyfluoran, 3-diethylamino 6-methoxyfluoran, 3-diethylamino 7-
Methoxyfluorane, 3-diethylamino-7-lylolofluorane, 3-diethylamino-6methyl-7-chlorofluorane, 3-diethylamino-6,7-dimethylfluorane, 3-(N-ethyl-p-toluidino)-7- Methylfluorane, 3-diethylamino-7-N-acetyl N-methylaminofluorane, 3-diethylamino-
7-N-methylaminofluorane, 3-diethylamine-7-dihendylaminofluorane, 3-diethylamino-7-(N-methyl-N-hensylamino)fluorane, 3-diethylamino 7-(N-chloroethyl-N −
methylamino)0 Fluoran, 3-diethylamino-7-N-diethylaminofluoran, 3-(N-ethyl-p-toluidino)-
6-Methyl-7-phenylaminofluorane, 3-(N
-ethyl-p-toluidino)6-methyl-7-(p~toluidino)fluoran, 3-diethylamine-6-methyl-7-phenylaminofluoran, 3-dibutylamino-6methyl=7-phenylaminofluoran, 3-diethylamino-7-(2-carbomethoxy-phenylamino)fluorane, 3-(N-ethyl N-isoamyl)amino-6-methyl-7-phenylaminofluorane, 3
-(N-cyclohexyl-N-methylamino)-6-methyl-7-phenylaminofluorane, 3-pyrrolidino-6-methyl-7-phenylaminofluorane, 3-piperidino-6-methyl-7- Phenylaminofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 3-diethylamino-7(0-chlorophenylamino)fluorane, 3-dibutylamino-7-(o-
chlorophenylamino)) fluorane, 3-(N-ethyl-N-teI-lahydrofurfuryl)amino-6-methyl-7-phenylaminofluorane, 3-(N-methyl-
Nn-propyl)amino-6-methyl-7-phenylaminofluorane, 3-pyrrolisino-6-methyl-7-p
-Butylphenylaminofluorane, 3-(N-ethyl-N-n-propyl)amino 6-methyl-7-phenylaminofluorane, 3(N-ethyl-N-isobutyl)
Amino-6methyl-7-phenylaminofluorane, 3
-(N-methyl-N-n-hexyl)amino-6-methyl-7-phenylaminofluorane, 3-IN ethyl-
Fluoran dyes such as N-n-hexyl)amino-6-methyl-7-phenylaminofluorane and 3-(N-ethyl-N-cyclopentyl)amino-6-methyl-7-phenylaminofluorane. Of course, the dyes are not limited to these dyes, and two or more types of dyes can be used in combination.

The ratio of the basic dye to the heat-fusible substance represented by the general formula CI and other heat-fusible substances is not particularly limited, but is usually 100% of the basic dye. The compound represented by formula (1) is added in an amount of 1 to 1000 parts by weight, preferably 10 to 30 parts by weight.
It is desirable to adjust the amount within a range of approximately 0 parts by weight.

In the present invention, the coloring agent constituting the recording layer of the heat-sensitive recording material is not particularly limited, and it has the property of liquefying, vaporizing, or dissolving when the temperature rises, and comes into contact with the basic dye. Various substances are used that have the property of causing coloration.

Typical specific examples include activated clay, acid clay, acupulgite, bentonite, colloidal silica, inorganic acidic substances such as aluminum silicate, 4tert-butylphenol, 4-hydroxyphenoxide, α-naphthol, β-naphthol, 4-hydroxy acetophenol,
4-tert-octylcatechol, 2,2'-dihydroxydiphenol, 22'-methylenebis(4-methyl-6-tert-isobutylphenol), 4,4'isopropylidenebis(2-tert-butylphenol), 4.4'-5ec-butylidene diphenol, 4-phenylphenol, 4,4'-isopropylidene diphenol, 22'-methylenebis(4-chlorophenol), hydroquinone 4.4'-cyclohexylidene diphenol, 4-hydroxy Hensyl benzoate, 4
-dimethyl hydroxyphthalate, hydroxymonohensyl ether, 4-hydroxy-4'-isopropyloxydiphenylsulfone, 3',4'-tetramethylene-4-hydroxydiphenylsulfone, 4,4'-
(1,3-dimethylbutylidene)bisphenol, 4.
4'-(1-phenylethylidene)bisphenol, 4
．． Phenolic compounds such as 4'-(p-phenylene diisopropylidene) diphenol, 4.4' (m-phenylene diisopropylidene) diphenol, novolak type phenolic resin, phenol polymer, benzoic acid, p-
tert-butylbenzoic acid, trichlorobenzoic acid, terephthalic acid, 3-sec-butyl-4-hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, salicylic acid , 3-isopropylsalicylic acid, 3-t
ert-butylsalicylic acid, 3-hensylsalicylic acid,
3-(α-methylhensyl)salicylic acid, 3-chloro-
5-(α-methylhensylsalicylic acid, 3,5-di-t
er t-butylsalicylic acid, 3-phenyl-5-(α
, α-dimethylhensyl)salicylic acid, 3,5-di-α
- aromatic carboxylic acids such as methylhenzylsalicylic acid,
and these phenolic compounds, salts of aromatic carboxylic acids with polyvalent metals such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin, nickel, and also zinc, magnesium, aluminum,
Examples include organic acidic substances such as complex compounds of polyvalent metal salts such as calcium, titanium, manganese, tin, and nickel, and organic compounds such as antipyrine, pyridine, and dimethylaminoantipyrine. In addition, two or more types of coloring agents may be used in combination, if necessary.

The ratio of the coloring agent and basic dye used is not necessarily limited, but is usually 100 to 700 parts by weight, more preferably 150 parts by weight, per 100 parts by weight of the basic dye.
A coloring agent of ~400 parts is blended.

Preparation of coating liquids containing these generally uses water as a dispersion medium,
Prepared by dispersing a basic dye, a coloring agent, and a thermofusible substance represented by the general formula [■] together or separately using a stirring/pulverizing machine such as a ball mill, I-lighter, or sand mill. be done. Such coating liquids usually contain starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, styrene/maleic anhydride copolymer salt, styrene/acrylic acid copolymer salt, The styrene-butadiene copolymer emulsion etc. is 10 to 40% by weight of the total solid content, preferably 15 to 40% by weight.
It is blended in an amount of about 30ffi.

Furthermore, various auxiliary agents can be added to the coating liquid.
For example, dispersants such as dioctyl sodium sulfosuccinate, sodium todecylhenzenesulfonate, sodium lauryl alcohol sulfate ester, fatty acid metal salts, ultraviolet absorbers such as triazole type, and other antifoaming agents,
Examples include fluorescent dyes and colored dyes. In addition, a dispersion or umulsion of stearic acid, polyethylene, carnauba wax, paraffin wax, zinc stearate, calcium stearate, ester wax, etc. is added to prevent the thermal recording medium from causing sticking due to contact with recording equipment or recording heads. I can do seven things too.

In addition, kaolin, clay, talc, calcium carbonate, calcined resin,
Pigments such as titanium oxide, diatomaceous earth, particulate anhydrous silica, and activated clay may also be added.

As the support, paper, plastic film, synthetic paper, etc. can be used, but paper is most preferably used in terms of cost, coatability, etc. The amount of the coating liquid forming the recording layer applied to the support is not particularly limited, but is usually in the range of 2 to 12 g/rt', preferably 3 to Log/rrr in terms of dry weight. adjusted.

The method for forming the recording layer is not particularly limited either, and can be formed by conventionally known techniques. For example, a coating liquid for a heat-sensitive recording layer is applied onto a support using a suitable coating device such as an air knife coater, a blade coater, a bar coater, a gravure coater, a curtain coater, etc., and dried to form a heat-sensitive recording layer.

Note that it is also possible to provide an overcoat layer on the recording layer for the purpose of protecting the recording layer, and it is of course also possible to provide a protective layer on the back side of the support or an undercoat layer on the support. In addition, various known techniques in the field of heat-sensitive recording material production, such as applying an adhesive to the back surface of the support, can be added.

"Example" The present invention will be described in more detail with reference to Examples below, but the present invention is of course not limited to these.

Further, unless otherwise specified, parts and percentages in the examples indicate parts by weight and percentages by weight, respectively.

8 Example 1 Lower-concave female moon-related firing resin (trade name: Ansilex, manufactured by Engelhard) 100 parts styrene-butadiene copolymer latex (solid content: 50%)
15 parts polyvinyl alcohol 10%
yk melt e 309n water
An undercoat opening coating solution was prepared by mixing 200 parts of the above composition.

The obtained coating liquid was applied to 50 g/po high-quality paper so that the coating amount after drying was 10 g/n, and dried to form an undercoat layer.

Agony Record #Clothing (1) Preparation of Solution A 3-Dibutylamino-6-methyl-7-phenylaminofluorane 10 parts 1.2-bis(benzyloxy)ethane 20 parts Methylcellulose 5% aqueous solution 15 parts Water 12
0 parts ■ This composition was ground in a sand mill until the average particle size was 2.0 μm.

(2) Preparation of Solution B 4.4'-Isopropylidenediphenol 30 parts Methylcellulose 5% aqueous solution 30 parts Water
70 parts of this composition was ground in a sand mill until the average particle size was 2.0 μm.

(3) Formation of recording layer 165 parts of liquid A, 130 parts of liquid B, 30 parts of silicon oxide pigment, 2
150 parts of 0% oxidized starch aqueous solution and 55 parts of water were mixed and stirred to prepare a coating liquid. The resulting coating solution was coated onto the undercoat layer at a dry weight of 5.0 g/rW and dried to obtain a heat-sensitive recording paper.

Example 2 Everything was the same as in Example 1 except that 20 parts of 1,2-bis(hensyloxy)ethane in the preparation of Solution A in Example 1 was replaced with 20 parts of 1,2-bis(3-methylbenzyloxy)ethane. A recording paper with zero heat sensitivity was obtained.

Example 3 All procedures were carried out in the same manner as in Example I except that 20 parts of 12-bis(benzyloxy)ethane in the preparation of Solution A in Example 1 was replaced with 20 parts of 1,2-bis(2-(phenyl)vinyloxy)ethane. A thermosensitive recording paper was obtained.

Comparative Example 1 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that 20 parts of 12-bis(benzyloxy)ethane was used in preparing Liquid A.

Comparative Example 2 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that 20 parts of 1,2-bis(hensyloxy)ethane was replaced with 20 parts of stearamide in the preparation of Liquid A.

Each of the thermal recording papers thus obtained was printed on a thermal recording device using a Kyocera thermal recording head (voltage: 16V).

Pulse cycle: 5 m 5 ec) was used to record pulse widths of 10, 30 m sec, and 0.45 m sec, and the color density was measured using a Macbeth densitometer (model RD-100R, using an amber filter). The results are shown in Table 1.

In addition, these heat-sensitive recording papers were subjected to a storage test 1 for 24 hours at 60°C or 24 hours at 40°C and 190% RH, and changes in background density (fog) were measured using a Macbeth densitometer. The results are also listed in Table 1.

Table 1 2 "Results" As is clear from Table 1, the heat-sensitive recording material of the present invention was excellent in color intensity and color density, and was excellent in background cover IJ.

Claims (1)

[Scope of Claims] A heat-sensitive recording material comprising, on a support, a heat-sensitive recording layer containing a colorless or light-colored basic dye and a coloring agent that develops color upon contact with the basic dye. 1. A heat-sensitive recording material, characterized in that the layer contains at least one type of thermofusible substance represented by the following general formula [I]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [In the formula, R_1 and R_2 may be the same or different and represent an optionally substituted alkylene, alkenylene, or alkynylene group having 1 to 4 carbon atoms. ,X,Y,X
_1 and Y_1 may be the same or different and represent a hydrogen atom, an alkyl group, an acyl group, a halogen atom, an alkoxyl group, an alkoxycarbonyl group, an aryl group, an aryloxycarbonyl group, a substituted or unsubstituted amino group, or a carbamoyl group. represent. Moreover, X, Y, X_1, and Y_1 may be bonded to each other to form a cyclization. Furthermore, n represents an integer of 2 to 4. ]