JPH03240587A - Thermal recording material - Google Patents

Abstract

PURPOSE:To improve a compatibility with a colorless dye, a color developer, and the like, enhance a color forming sensitivity, and reduce a background fog by incorporating at least one of specific amide compounds in a thermal color-forming layer. CONSTITUTION:In a thermal recording material provided with a thermal color- forming layer containing a colorless or light-colored electron donative dye precursor and an electron accepting substance reacting with this dye precursor to produce a color on a substrate, the thermal color-forming layer is formed by containing at least one of amide compounds shown by a general formula I (R1 is hydrogen atom, methyl, or a group shown by II R2, R3, and R4 are hydrogen atom, 1 - 21 C alkyl, or 2 - 21 C alkenyl, aryl which may has a substituent, aralkyl which may has a substituent, or aryloxyalkyl which may has a substituent. A is 2 - 4 C alkylene which may be branched). In this manner, a thermal recording material enhanced in color density at the time of thermal recording and also color-forming sensitivity can be obtained.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to heat-sensitive recording materials.

(Prior art) Conventional general heat-sensitive recording materials have colorless or light-colored electron-donating dye precursors (hereinafter abbreviated as "colorless dyes") and electron-accepting properties on a support such as paper or film. A two-component coloring system consisting of a substance (hereinafter abbreviated as a "color developer") is further provided with a heat-sensitive coloring layer in which a binder, a sensitivity improver, a lubricant, a filler, and other auxiliaries are dispersed. is a special public official in 1977-
No. 4160 and Japanese Patent Publication No. 45-14039.

This type of two-component color-forming heat-sensitive recording material allows a color image to be easily obtained by heating with a heating element (thermal head, thermal pen, etc.), and has the following characteristics.

(I) - Secondary color development, no need for development or fixing.

(2) There is no need to replenish toner, etc., and maintenance of the recording machine is easy.

(3) When paper is used as a support, the quality of the paper is close to that of synthetic paper, and there is no discomfort.

(4) High color density and clear images can be obtained.

(5) By changing the type of colorless dye, different color tones can be easily obtained.

Due to these advantages, two-component coloring type heat-sensitive recording materials are the most widely used among heat-sensitive recording materials, and especially in recent years,
Its use in fields such as facsimiles, printers, word-of-mouth recording, and labels is increasing significantly.

By the way, for example, in the recent field of computer science, recording speeds have been increasing as speeds have increased43.
There is also a strong demand for improved thermal responsiveness of thermal recording paper so that sufficient color density can be obtained with less thermal energy.

(Problem to be solved by the invention) However, research has been carried out on various coloring sensitivity improvers to improve thermal responsiveness. The unfavorable tendency of increasing color density has increased, and at present no heat-sensitive recording material has been obtained that satisfies both of these color development sensitivity and background fog. .

That is, conventional coloring sensitivity improvers (sensitizers) have the disadvantage that they cause uneven printing when printed using high-speed facsimiles or energy-saving facsimiles, and that image reproducibility is not sufficient.

Further, if a substance with a low melting point is mixed into the coloring layer, the coloring sensitivity can be improved, but there is a drawback that background fogging occurs.

The present invention uses a sensitizer that is highly compatible with a colorless dye, a color developer, etc., and uses a thermal recorder 911. FL fee is provided.

(Means for Solving Problem m1) The heat-sensitive recording material of the present invention that achieves the above object has a colorless or light-colored electron-donating dye precursor on a support, and a colorless or light-colored electron-donating dye precursor that is reacted with the dye precursor. A thermosensitive recording material provided with a thermosensitive coloring layer containing an electron-accepting substance for color development, characterized in that the thermosensitive coloring layer contains at least one kind of amide compound represented by the following general formula (I). Material 1 R2-CN-8-QC-R3(T)1110 (However, 81 in formula (I) is a hydrogen atom, a methyl group, or a group represented by -A-QC-R4.

1 R2, R3, R4 are a hydrogen atom, an alkyl group having 1 to 21 carbon atoms, an alkenyl group having 2 to 21 carbon atoms, an aryl group which may have a substituent, or a substituent. It is an aralkyl group or an allylokynealkyl group which may have a substituent. A is an optionally branched alkylene group having 2 to 4 carbon atoms.

R2, R3, and R4 may be, for example, a phenoxymethyl group substituted with a substituent in group 1 below, or a phenyl group or a hensyl group substituted with a substituent in group 1 below. preferable.

■Group, aryl group, haloken, nitro group, carbon number 1-1
2 alkyl group, or alkenyl group having 2 to 12 carbon atoms, or alkoxy group having 1 to 12 carbon atoms, halogen, 2 I to 2 groups, or alkyl group A having 1 to 4 carbon atoms, There are four optionally branched alkylene groups, preferably selected from ethylene, propylone, butylene, and inbutylene groups. ) (Function) The reason why the compound of formula 2-handed N) exhibits a remarkable sensitizing effect when used as a sensitizer is considered to be as follows.

That is, the sensitizer itself according to the present invention has a high thermal dissolution rate, and has a high thermal dissolution diffusion rate and saturation solubility for colorless dyes or color developers.9. This is thought to be because the colorless dye and color developer quickly form a color-forming composition.

The present invention will be explained in more detail below.

Representative examples of the compound of formula (I) above are shown below, but the present invention is not intended to be limited thereto.

1] 1 lb 0 4 In the heat-sensitive coloring layer of the present invention, for example, stearic acid amide, stearic acid amide,
Stearic acid methylene bisaccharide, oleic acid acid,
Fatty acid amines such as palmitic acid amide and coconut fatty acid amide can be contained, and various known compounds can also be used in combination.

The colorless dyes and color developers used in the present invention are not particularly limited as long as they are used in general pressure-sensitive recording materials, heat-sensitive recording materials, etc. Colorless dyes include triarylmethane compounds, diphenylmethane compounds, and xanthine. These include deazine-based compounds, deazine-based compounds, spirolan-based compounds, and the like. Specific examples of colorless dyes are shown below, and the present invention is not limited to these.

To give some examples of colorless dyes, examples of triarylmethane compounds include 3.3-bis(p-dimethylaminophenyl)-6-dimethylacunophthalide (i.e., crystal violet lactone), -dimethylaminophenyl)phthalide, 3-(p-dimethylacunophenyl)-3-(I,3-cymedylintole-3-
yl)phtali F, 3-(p-dimethylaminophenyl)
-3-(2-methylindol-3-yl)phthalide and the like are exemplified.

Examples of the diphenylmethane compounds include 4.4-histyl dimethylaminopencil ether, N-halophenyl leukoolamine, and N-2,4,5-trichlorophenyl leucoolamine.

Examples of xanthine compounds include rotamine B-anilinolactam, rotamine (p-2)-lino)lactam, 2
-(Shihensylamino)fluoran, 2-phenylamino-6-diedylaminofluorane, 2-(o-chloroaryno)-6-diedylaminofluorane, 2(3
, 4-dichloroanilino)-6-ethylaminofluorane, 2-anilino-3-methyl 6-piperidinofluorane, 2-phenyl 6-dinithylaminofluorane, 2
-anilino-3-methyl-6-cymedylaminofluorane, 2-anilino-3-methyl-6-N-methyl-N-
Ethyl akunofluorane, 2-anilino-3-methyl-
6-N~medyl-N-(isopropyl)acnofluorane, 2-anilino3-methyl-6-N-methyl-N-pentylaminofluorane, 2-anilino-3-methyl1 2 6-N-methyl-N -Cyclohexylaminofluorane, 2-anilino-3-methyl-6-ethylaminofluorane, 2-anilino-3chloro-6-dimethylacunofluorane, 2-anilino-3-methyl-6-N-ethyl-N -Isoacrylaminofluorane, 2-anilino3
-Methyl-6-N-methyl-N-isoamyl-Akunofluorane, 2-anilino-3-chloro-6-dinithylaminofluorane, 2-anilino-3-chloro-6-N-medyl-N-edylaminofluoran Oran, 2-anilino-3
-chloro-6-N-methyl-N-(isopropyl)aminofluorane, 2-anilino-3-chloro6-N-methyl-N-pentylaminofluorane, 2-anilino-3
-chloro-6-N-methyl-N-cyclohexylaminofluorane, 2-anilino-3-methyl-6-N-ethyl N-pentylaminofluorane, 2-anilino-3-
Chloro-6-N-ethyl-N-pentylaminofluorane, 2-(p-methylanilino)-3-methyl-6-dimethylaminofluorane, 2-(p-methylanilino)
-3-methyl-6-dinithylaminofluorane, 2-(
P-methylanilino)-3-methyl-6-N-methyl-N
-ethylaminofluorane, 2-(pmethylanilino)
-3-Methyl-6-N-methyl-N-(isopropyl)
Achnofluorane, 2-(p-methylanilino)-3-
Methyl-6-N-methyl-N-pentylaminofluorane, 2-(p-methylanilino)-3-methyl-6-N
-Methyl-N-cyclohexylaminofluorane, 2-
(p-methylanilino) = 3-methyl-6-N-ethyl-N-pentylaminofluorane, 2- (p-methylanilino)-3-chloro-6-dimethylaminofluorane, 2-(p-methylanilino) -3-chloro-6-ethylaminofluorane, 2-(pmethylanilino)-
3-chloro-6-N-methyl-N-ethylaminofluorane, 2-(Pmethylanilino)-3-chloro-6-N
-Methyl-N-(isopropyl)aminofluorane, 2
-(p-methylanilino)-3-chloro6-N-methyl-N-(isopropyl)aminofluorane, 2-(p-
methylanilino)=3-chloro-6-N-methyl-N-
Cyclohexylaminofluorane, 2-(p-methylanilino)-3-chloro-6-N-methyl-N-pentylaminofluorane, 2-(p-methylanilino)-3-
Chloro-6-N-ethyl-N-pentylaminofluorane, 2-anilino-3-methyl-6-N-methyl-N-furylmethylaminofluorane, 2-anilino-3-ethyl-6-N-methyl- Examples include N-furylmethylaminofluorane. .

Examples of thiazine compounds include henzoleucomethylene blue and p-nitrohensylleucomethylene blue.

As a spiropyran compound, 3-methyl-spiro-
Dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 33°-cyclosbirose dinaphthopyran, 3-benzylspiro-dinaphthopyran, 3-methyl-naphtho-
Examples include (3-methoxybenzo)-spiropyran and 3-probilsvirodibenzobilane.

In the heat-sensitive recording material of the present invention, the content of the colorless dye in the heat-sensitive coloring layer is preferably in the range of 02 to 10 g/m<2>.

In addition, the color developer that is used together with a colorless dye in the heat-sensitive coloring layer of a heat-sensitive recording material and causes the colorless dye to develop color is
An organic acidic substance that is solid at room temperature and heat-meltable is used, -
Examples include phenolic compounds, aromatic carbonic acid compounds, noholac type phenolic resins, etc.
Typical examples thereof include bisphenol derivatives, hydroxybenzoic acid esters, and salicylic acid esters. Further examples include inorganic acids such as clay, activated clay, activated silica, boric acid, and zinc oxide. The content of the color developer in the heat-sensitive coloring layer is 0.2 to 4.0 g/m
It is preferable to set it in the range of 2.

Among these color developers, phenolic compounds and aromatic carboxylic acid compounds are particularly preferred, and some examples include 2.2-bis(4°-hydroxyphenyl)propane, 2.2 -bis(4°-hydroxyphenyl)pentane, 2,2-bis(4-hydroxy-3°,5
°-dichlorophenyl)propane, 1,1-bis(4°
-hydroxyphenyl)cyclohexane, 2,2-bis(4'-hydroxyphenyl)hexane, 1,1-bis(4hydroxyphenyl)propane, ■, 1-bis(4
゛-Hydroxyphenyl)butane, 1.1-his(4゛-hydroxyphenyl)pentane, 1.1-bis(4゛-hydroxyphenyl)hexane, 1.1-his(4゛-hydroxyphenyl)hexane, 1.1-bis (4°
-hydroxyphenyl)-2-methyl-pentane, 1,
1-bis(4'-hydroxyphenyl)-2-ethyl-
Hexane, 1,1-bis(4°-hydroxyphenyl)
Dodecane, 3,3-bis(4'-hydroxyphenyl)
Pentane, l,2-his(4°-hydroxyfer)ethane, 1. )-bis(4'-hydroxyphenyl)sulfite, 1.1-bis(3'-allyl-4'-hydroxyphenyl)sulfone, 1. l bis(4°-hydroxyphenyl) sulfone, 4-hydroxy-4′-isopropoxydiphenyl sulfone, l, 1-bis(4′-hydroxyphenyl) ether, 2,2-bis(4′-hydroxy 3°, 5°-dichlorophenyl)butane, 2.4
-Phenyl dihydroxybenzoate, phenyl 2,4-dihydroxy-4'-methyl-benzoate, phenyl 2,4-dihydroxy-4'-chlorobenzoate, phenyl 2,4-dihydroxy-6-methylbenzoate, 2,4 .5-trihydroxybenzoic acid phenyl, 2,4-dihydroxy-6,4"-dimethylbenzoic acid phenyl, 2,4-dihydroxy6-methyl-4"-chlorobenzoic acid phenyl,
2.4-dihydroxybenzoic acid pencil, 2.4-dihydroxy-4'-methylbenzoic acid henzyl, 2.4-dihydroxy-4'-chlorobenzoic acid benzyl, 2.4-dihydroxy-6-methylbenzoic acid henzyl, 2 ,4. S
-benzyl trihydroxybenzoate, 2,4-dihydroxy-〇,4°-cymedylbenzoic acid m pencil, z, 4
-Dihydroxy 6-methyl-4°-Hensyl chlorobenzoate, 4-hydroxybenzoic acid edyl ester, 4-hydroxybenzoic acid propyl ester, 4-hydroxybenzoic acid isopropyl ester, 4-hydroxybenzoic acid benzyl ester, 4-hydroxy-4° -Compounds such as benzyl chlorobenzoate ester, benzyl 4-hydroxy-4°-methylbenzoate, benzyl 4-hydroxy-4°-ethylbenzoate, etc., but are not particularly limited to these. .

The heat-sensitive coloring layer according to the present invention preferably contains a filler, and such fillers include calcium carbonate, clay, fired clay, silica, zinc oxide, titanium oxide, talc, aluminum hydroxide, and hydroxide. Examples include inorganic white pigments such as magnesium, barium sulfate, and surface-treated silica, as well as organic fine particles such as starch, polystyrene resin, and urea-formalin resin.

Binding agents for binding colorless dyes, color developers, white organic pigments, etc. on the support include borihinyl alcohol and its derivatives, polyvinylpyrrolidone, starch and its derivatives, hydroxyl edyl cellulose, ethyl cellulose. , cellulose derivatives such as methyl cellulose and carboxymethyl cellulose, styrene maleic anhydride copolymer alkali salts, isobutylene maleic anhydride copolymer alkali salts, polyacrylic acid alkali salts, alginate alkali salts, polyacrylamide, casein, and ceratin, which are water-soluble. Polymers, also styrene/butadiene copolymers,
Various latexes such as polyurethane, polyvinyl acetate, and polyacrylic acid can be used.

Furthermore, depending on the application, waxes such as paraffin wax, carnauba wax, polyethylene wax, and medylol stearamide F, and lubricants such as zinc stearate and calcium 90 sudeate can be added. In order to improve water resistance, a crosslinking agent or the like that crosslinks the binder may be added. For applications requiring good recording stability, it is preferable to incorporate a preservation improver such as a phenolic antioxidant.

A blade coater is a conventional method for applying a heat-sensitive coloring layer on a support from a heat-sensitive paint produced using colorless dyes, color developers, pigments, binders, and other auxiliary agents. , air knife coater, roll coater, rot coater, and other known methods can be used.

In order to improve the storage stability of the heat-sensitive recording material of the present invention, it is preferable to provide an overcoat layer on the heat-sensitive coloring layer. -39078, Special Public Interest 1
The method described in No.-174, 78 can be used.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

First, dispersions A and B in which the following colorless dyes are dispersed, dispersions C and D in which a color developer is dispersed, and dispersions E and H in which a sensitizer is dispersed are mixed into a side glider. - Adjusted. The modified polyhinyl alcohol used was Gosselan L-3266, a trade name manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.

In addition, the number of blended parts indicates the number of M parts.

Colorless dye dispersion [A-night] 3-n-dibutylamino-6-methyl-7-anilinofluorane 10 parts 10% modified polyvinyl alcohol 10 parts water
,. @5 [Liquid B] 3-(N-ethyl-N-isoamyl)amino-6-methyl 7-anilinofluorane 10 parts 10
% modified polyvinyl alcohol 10 parts water
2
Add 0 parts of developer to the liquid [C? J)2] 1.1'-bis(p-hydroxyphenyl)bu(n(
Bisphenol A) 10% modified polyvinyl alcohol water [D? 4-Todroxy 4'-isopropoxydiphenyl sulfone 10% modified polyhinyl alcohol water sensitizer dispersion [E? Night] 1 10 parts 10 parts 20 parts 10 parts 10 parts 20 parts 10% modified polyvinyl alcohol 10 parts water 20 parts [F? Night] 10% denatured polyvinyl alcohol 10 parts water 20 parts [G? Yoko 1 10% denatured polyvinyl alcohol water 10 parts 20 parts [H solution] ■ 10% denatured polyvinyl alcohol 10 parts water

20 copies of colorless dye dispersion of A and B above for 7 nights and CD
Color developer portion W1. liquid, E-H sensitizer dispersion, 30
% calcium carbonate dispersion, 10 parts and 15 parts, respectively.
The mixture was mixed at a blending ratio of 15 parts and io parts, and 10 parts of a 10% solution of completely saponified polyvinyl alcohol (average degree of polymerization 1000) was added as a main binder to prepare heat-sensitive paints having the combinations shown in Table 1 below. However, the sensitizer dispersion liquid was not blended in the comparative example. Callite SA manufactured by Shiraishi Kogyo was used as the 34 lucium carbonate.

The intermediate layer and the heat-sensitive paint were each coated on a 45 g/m2 high-quality paper as a support at a dry weight of 9.
~1037m'' and 4~537m2 to obtain a heat-sensitive recording material.The above-mentioned intermediate layer used an inorganic filler layer mainly composed of fired clay, and the ratio of the inorganic filler to the binder was 100.
:10 (dry weight ratio). Stelone-butadiene latex was used as the binder.

The heat-sensitive recording material on each side shown in Table 1 below, prepared as described above, was processed using a super calender until the Bekk smoothness was 4.
After adjusting the time to 00 to 600 seconds, the coloring sensitivity was measured using a thermal head printing device manufactured by Daiichi Denki.

The color density was measured using a Macbeth densitometer (RD-5143 manufactured by Machbeth) at an applied power of 0.4 W/dot, a pulse period of 4.0 m5ec, and a thermal head resistance of 1191 Ω. 1
I got the results in the table.

Condolence table However, in the table: ◎...Excellent.

×: Inferior As is clear from the results in this table, the heat-sensitive recording materials of each example having a specific structure of the present invention exhibited color development sensitivity superior to that of the comparative example.

Although the above embodiments have been described with reference to specific examples and numerical values of the present invention, it is of course possible to make various changes and modifications without departing from the broad spirit and scope of the present invention.

(Effects of the Invention) As described in detail above, according to the present invention, it is possible to obtain a heat-sensitive recording material that has high color density and high color sensitivity during heat-sensitive recording, and the present invention is extremely useful industrially. be.

4 others

Claims (1)

[Scope of Claims] 1. A heat-sensitive recording in which a heat-sensitive coloring layer containing a colorless or light-colored electron-donating dye precursor and an electron-accepting substance that develops color by reacting with the dye precursor is provided on a support. A heat-sensitive recording material characterized in that the heat-sensitive coloring layer contains at least one kind of amide compound represented by the following general formula (I). (I) R_1 in the formula is a hydrogen atom, a methyl group, or a group represented by ▲There are numerical formulas, chemical formulas, tables, etc. ▼. R_2, R_3, R_4 are hydrogen atoms, carbon atoms 1 to 21
an alkyl group having 2 to 21 carbon atoms, an aryl group that may have a substituent, an aralkyl group that may have a substituent, or an aryloxyalkyl group that may have a substituent It is. A is an optionally branched alkylene group having 2 to 4 carbon atoms. ) 2 In claim 1, R_2, R_3, R_4 are phenoxymethyl groups substituted with the following substituents [aryl group, halogen, nitro group, alkyl group having 1 to 12 carbon atoms, carbon An alkenyl group having 2 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. ] 3 In claim 1, R_2, R_3, R_4 are phenyl groups or benzyl groups substituted with the following substituents [halogen, nitro group, or alkyl group having 1 to 4 carbon atoms]. 4. The heat-sensitive recording material according to claim 1, wherein A is selected from an ethylene group, a propylene group, a butylene group, and an isobutylene group.