JPH04142978A - Thermal recording material - Google Patents

Abstract

PURPOSE:To make thermal response and image preservability excellent by adding specific 1-phenyl-3-x-alkoxyphenyloxy-1-propene. CONSTITUTION:In a thermal recording material containing a usually colorless or light-colored dye precursor and an electron acceptive compound (developer) reacting with the dye precursor at the time of heating to develop the color of the dye precursor, 1-phenyl-3-x-alkoxyphenyloxy-1-propene(wherein x is either one of o-, m-and p-positions and an alkoxy group has 2-8 carbon atoms) is added to impart excellent thermal response, high developed color density and excellent image preservability. The developer is added in an amount of 5-400%, especially pref. 20-30 % by wt. of the dye precursor and 1-phenyl-3-x- alkoxyphenyloxy-1-propene is added in an amount of 5-400%, especially pref. 20-300 % by wt. of the developer.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a heat-sensitive recording material, and particularly to a heat-sensitive recording material that has excellent heat responsiveness and image storage stability.

[Conventional technology]

A heat-sensitive recording material generally has a heat-sensitive recording layer on a support, the main components of which are an electron-donating, usually colorless or light-colored dye precursor and an electron-accepting developer. , by heating with laser light etc., a dye precursor and a color developer react instantaneously to obtain a recorded image, and are disclosed in Japanese Patent Publication No. 43-4160, Japanese Patent Publication No. 15-1/1039, etc. has been done. These heat-sensitive recording materials have the advantages of being able to record with relatively simple equipment, being easy to maintain, and producing no noise. It is used in a wide range of fields, including ticket vending machines. Particularly in the field of facsimile, the demand for heat-sensitive methods is increasing significantly, and along with this, efforts are being made to increase speed, miniaturize devices, and lower prices in order to reduce transmission costs. As a result, the amount of energy applied for image printing has been steadily decreasing in recent devices. Therefore, there has been a strong demand for the development of highly sensitive heat-sensitive recording materials with high thermal responsiveness that can cope with such higher speed and lower energy facsimiles. In high-speed recording, it is necessary to use the small amount of thermal energy released from the thermal head in an extremely short period of time (usually less than 1 millisecond) for the color reaction to form a high-density color image. be. As a means to achieve the above objective, it is proposed to use a thermofusible substance with a relatively low melting point as a color development accelerator or sensitizer together with a dye precursor and an electron-accepting compound that causes the dye precursor to develop color. has been done. For example, JP-A-57
-64593, JP-A-58-87094 disclose naphthol derivatives;
JP-A-58-110289, JP-A-59-15393
The patent publication discloses naphthoic acid derivatives in JP-A-58-7249.
No. 9 and JP-A-58-87088 propose the use of ether and ester derivatives of phenolic compounds. However, the heat-sensitive recording materials produced using these methods are still insufficient in terms of thermal response, color development sensitivity, etc. In addition, as an invention related to the present invention, JP-A-63-21
No. 181, 1-phenyl-3-aryloxy-1
- A heat-sensitive recording material containing propene as a thermofusible substance has been disclosed, but the compounds exemplified in this publication are still insufficient in thermal responsiveness and image preservability. OBJECT OF THE INVENTION An object of the present invention is to obtain a heat-sensitive recording material that has excellent thermal responsiveness and excellent image storage stability.

[Structure of the invention]

In a heat-sensitive recording material containing a normally colorless or light-colored dye precursor and an electron-accepting compound (color developer) that reacts with the dye precursor upon heating to cause the dye precursor to develop color, 1-phenyl-5-
x-alkoxyphenyloxy-1-propene (however,
X represents either the o, m or p position, and the alkoxy group is a group having 2 or more and 8 or less carbon atoms. ), it was possible to obtain a heat-sensitive recording material with excellent thermal responsiveness, high color density, and excellent image storage stability. Specific examples of the compounds of the present invention include those listed below, but the present invention is not limited thereto. (1) 1-cinnamyloxy-4-ethoxybenzene (2) 1-cinnamyloxy-4-n-propoxybenzene (3) 1-cinnamyloxy-4-(l-methylethoxy)benzene (4) 1 -n-butoxy-4-cinnamyloxybenzene (5) 1-cinnamyloxy-4-(l-methylpropoxy)benzene (6) 1-cinnamyloxy-4-(2-methylpropoxy)benzene (7) 1-cinnamyloxy-4-(l-ethylethoxy)benzene (8) 1-cinnamyloxy-4-(l,1-dimethylethoxy)benzene (9) 1-cinnamyloxy-4-n-pentyloxy Benzene (10) 1-cinnamyloxy-4-(l-methylbutoxy)benzene (11,) 1-cinnamyloxy-4-(2-methylbutoxy)benzene (12) 1-cinnamyloxy-4-( 5-Methylbutoxy)benzene (13) 1-cinnamyloxy-4-(l,1-dimethylpropoxy)benzene (14) 1-cinnamyloxy-4-(1,2-dimethylpropoxy)benzene (15) 1 -Cinnamyloxy-4-(2,2dimethylpropoxy)benzene (16) 1-cinnamyloxy-4-(l-ethylpropoxy)benzene (17) 1-cinnamyloxy-4-n-hexyloxybenzene (18) 1-cinnamyloxy-4-(l-methylpentyloxy)benzene (19) 1-cinnamyloxy-4-(2-methylpentyloxy)benzene (20) 1-cinnamyloxy-4-( 5-Methylpentyloxy)benzene (21) 1-cinnamyloxy-4 dimethylbutoxy)benzene (22) 1-cinnamyloxy-4 dimethylbutoxy)benzene (23) 1-cinnamyloxy-4 dimethylbutoxy)benzene ( 24)]-]Cinnamyloxy-4 dimethylbutoxybenzene (25) 1-cinnamyloxy-4 dimethylbutoxy)benzene (26)]-]Cinnamyloxy-4 dimethylbutoxybenzene (27) 1-cinnamyloxy-4 dimethylbutoxy ) Benzene (28) 1-cinnamyloxy-4-rubutoxy) Benzene (29) i-cinnamyloxy-4-ruoxybenzene (30) 1-cinnamyloxy-4 (l. (1° (1° (2°) (2゜(3゜ethiethyheptemethyfluhexyloxy)benzene (31,)j-cinnamyloxy-4 dimethylpentyloxy)benzene (32)1-cinnamyloxy-4 dimethylpentyloxy)benzene (33) 1 -Cinnamyloxy-4 dimethylpentyloxy)benzene (34) 1-cinnamyloxy-4 lupentyloxy)benzene (35) 1-cinnamyloxy-4 3-trimethylbutoxy)benzene (36) 1-cinnamyloxy -4-1,2-dimethylpropoxy) (37) i-cinnamyloxy-4-2,2-dimethylpropoxy) (38) 1-cinnamyloxy-4-diethylpropoxy)benzene (39)]-]cinnamyl oxy-4propyl-2methylpropoxy) (40) 1-cinnamyloxy-4 (l, 1 (1,2 (1,4 ,1 (1-isobenzene n-octyloxybenzene (41) 1-cinnamyloxy-4-(l-methylhebutyloxy)benzene (42) 1-cinnamyloxy-4-(l,5dimethylhexyloxy)benzene (4,3) 1-cinnamyloxy-4-(l-ethylhexyloxy)benzene (44) i-cinnamyloxy-4-(2-ethylhexyloxy)benzene (45): I-cinnamyloxy- 4-(2-methyl-
1-ethylpentyloxy)benzene (46) 1-cinnamyloxy-4-(2,4゜4-trimethylpentyloxy)benzene (47) 1-cinnamyloxy-4-
(2-propylpentyloxy)benzene (48)]-]cinnamyloxy-2-ethoxybenzene (49) 1-cinnamyloxy-3-ethoxybenzene (50)]-cinnamyloxy: 3-(1,1 (dimethylethoxy)benzene The compound of the present invention can be easily synthesized by known methods. For example, it can be synthesized by reacting an alkoxyphenol such as 4-ethoxyphenol or 4-butoxyphenol with cinnamyl halide under alkaline conditions. It can also be synthesized by reacting 4-cinnamyloxyphenol with an alkylating agent such as diethyl sulfate or propyl iodide under alkaline conditions. Here, specific synthesis examples of the compound represented by the above general formula will be shown, but the present invention is not limited thereto. (Synthesis Example) Synthesis of 1-cinnamyloxy-4-ethoxybenzene (compound of Example 1) 4-ethoxyphenol (15.2 g) was mixed with N. Dissolve in 50 ml of N-dimethylformamide. Potassium carbonate (15.2 g) is added and the reaction is heated to 60°C. Cinnamyl chloride (1, 5, 3 g) is added dropwise over about 30 n minutes while maintaining the temperature at 60-70°C. After the dropwise addition was completed, stirring was continued at 60°C for an additional 3 hours. After the reaction is completed, the reaction solution is poured into water 11 and the precipitated solid content is filtered. After drying, the residue was recrystallized from isopropyl alcohol to obtain 21.2 g of 1-cinnamyloxy-4-ethoxybenzene (melting point: 106'C). Next, a specific method for producing the heat-sensitive recording material according to the present invention will be described. The heat-sensitive recording material according to the present invention generally has an electron-donating, usually colorless or light-colored dye precursor and an electron-accepting compound as main components on a support, and these are dispersed and coated in a binder to form a heat-sensitive recording layer. By heating with a thermal head, thermal pen, laser beam, etc., a dye precursor and an electron-accepting compound react instantaneously to obtain a recorded image.
It is disclosed in Japanese Patent Publication No. 3-4160, Japanese Patent Publication No. 45-14'039, etc. Further, pigments, sensitizers, antioxidants, anti-sticking agents and the like are added to the heat-sensitive recording layer as necessary. The dye precursor used in the heat-sensitive recording material according to the present invention is not particularly limited as long as it is generally used in pressure-sensitive recording paper or heat-sensitive recording paper. Specific examples include (1) triarylmethane compounds 3.3-bis(p-dimethylaminophenyl) 6-dimethylaminophthalide (crystal violet lactone), 3.3-bis(p-dimethylaminophenyl) ) Phthalide, 3-(p-dimethylaminophenyl)-3-(1
, 2-dimethylindol-3-yl)phthalide, 3-
(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-phenylindole-3-
yl) phthalide, 3,3-bis(1,2dimethylindol-3-yl)-5-dimethylaminophthalide, 3,
3-bis(1,2-dimethylindol-3-yl)-
6-dimethylaminophthalide, 3,3-bis(9-ethylcarbazol-3-yl)-5-dimethylaminophthalide, 3,3-bis(2-phenylindol-3-yl)-5-dimethylamino phthalide, 3-p-dimethylaminophenyl-5-(1-methylpyrrol-2-yl)-6-dimethylaminophthalide, etc., (2) diphenylmethane compounds 4.4'-bis(dimethylaminophenyl)benz Hydryl benzyl ether, N-chlorophenyl leuco auramine, N-2,4,5-)lichlorophenyl leuco auramine, etc. (3) Xanthine compounds Rhodamine B anilinolactam, Rhodamine B p-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3-diethylamino-7-phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-chloro -7-methylfluorane, 3-diethylamino-7-(5,4-dichloroanilino)fluorane, 3-diethylamino-7
-(2-chloroanilino)fluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(N
-ethyl-N-1lyl)amino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-(N-ethyl-N-tolyl)amino6- Methyl-7-phenylfluoran, 3-diethylamino-7-(4-nitroanilino)fluoran, 3
-dibutylamino-6-methyl-7anilinofluorane, 3-(N-methyl-N-propyl)amino-6-methyl-7-anilinofluorane, 3-(N-ethyl-N-
isoamyl)amino-6-methyl-7-anilinofluorane, 3-(N-methyl-N-cyclohexyl)amino 6-methyl-7-anilinofluorane, 3-(N-ethyl-N-tetrahydrofuryl)amino -6-methyl-7
-anilinofluorane, etc., (4) Thiazine compounds benzoylleucomethylene blue, p-nitrobenzoylleucomethylene blue, etc., (5) Spiro compounds 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3 '-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho-(3-methoxybenzo)spiropyran, 3-propylspirobenzopyran, etc., which may be used alone or in combination of two or more.' The two can be mixed and used. The color developer is not particularly limited as long as it is an acidic substance commonly used in thermal paper. For example, polyvalent metal salts such as phenol derivatives, aromatic carboxylic acid derivatives, N, N'diarylthiourea derivatives, and zinc salts of organic compounds can be used. Particularly preferred are phenol derivatives, such as p-phenylphenol, p-hydroxyacetophenone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, and 4-hydroxy-4'-isopropoxydiphenylsulfone. Hydroxy-4'-
Benzenesulfonyloxydiphenylsulfone, 1,1
-bis(p-hydroxyphenyl)propane, ■, 1-
Bis(p-hydroxyphenyl)pentane, 1,1-bis(p-hydroxyphenyl)hexane, 1.1-bis(p-hydroxyphenyl)cyclohexane, 2.2-
Bis(p-hydroxyphenyl)propane, 2,2bis(p-hydroxyphenyl)hexane, 1゜1-bis(
p-hydroxyphenyl)-2-ethylhexane, 2,
2-bis(3-chloro-4-hydroxyphenyl)propane, 1,1-bis(p-hydroxyphenyl)-1-phenylethane, 1,3-di[2-(p-hydroxyphenyl)2-propyl]benzene , 1,3-G [2(
3,4-dihydroxyphenyl)-2-propyl]benzene, 1-94-di[2-(p-hydroxyphenyl)-2-propyl]benzene, 4゜4'-dihydroxydiphenyl ether, 4゜4'-dihydroxydiphenyl Sulfone, 3゜3'-dichloro-4,4'-dihydroxydiphenylsulfone, 3,3'-diallyl-
4,4' dihydroxydiphenyl sulfone, 3,3'
-dichloro-4,4'-dihydroxydiphenyl sulfide, 2,2-bis(4-hydroxyphenyl)methyl acetate, 2,2-bis(4-hydroxyphenyl)butyl acetate, 4,4'-thiobis(2- t-butyl-5-methylphenol), 2,2'bis(4-hydroxyphenylthio)diethyl ether, 1,7-di(4-hydroxyphenylthio)-3,5-dioxahebutane, p-hydroxybenzoic acid Examples include benzyl, chlorobenzyl p-hydroxybenzoate, dimethyl 4-hydroxyphthalate, benzyl gallate, stearyl gallate, salicylanilide, 5-chlorosalicylanilide, and the like. Binders used in heat-sensitive recording materials include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein,
Alkali salts of polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, acrylic amide/acrylic ester copolymer, acrylic amide/acrylic ester/methacrylic acid ternary copolymer, styrene/maleic anhydride copolymer , water-soluble adhesives such as alkali salts of ethylene/maleic anhydride copolymers, polyvinyl acetate, polyurethane, polyacrylic esters, styrene/butadiene copolymers, acrylonitrile/butadiene copolymers, methyl acrylate/butadiene copolymers Examples include polymers and latexes such as ethylene/vinyl acetate copolymers. In addition, N-
Waxes such as hydroxymethyl stearamide, stearamide and palmitic acid amide, naphthol derivatives such as 2-benzyloxynaphthalene, biphenyl derivatives such as p-benzylbiphenyl and 4-allyloxybiphenyl, -methylphenoxy)
Polyether compounds such as ethane, 2.2'-bis(4-methoxyphenoxy) diethyl ether, bis(4-methoxyphenyl) ether, diphenyl carbonate, dibenzyl oxalate, bis(p-methylbenzyl) oxalate, etc. Carbonic acid or oxalic acid diester derivatives can be added in combination. Examples of the pigment include diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, urea-formalin resin, and the like. In addition, higher fatty acid metal salts such as zinc stearate and calcium stearate, waxes such as paraffin, oxidized paraffin, polyethylene, oxidized polyethylene, stearic acid amide, and castor wax are used to prevent head wear and stickiness, as well as dioctyl sulfosuccinate. Dispersants such as sodium chloride, ultraviolet absorbers such as benzophenone and benzotriazole, and surfactants, fluorescent dyes, and the like are added as necessary. As the support used in the present invention, paper is mainly used, but nonwoven fabric, plastic film, synthetic paper, metal foil, etc., or a composite sheet of a combination of these can also be used as desired. In addition, in the production of heat-sensitive recording materials, an overcoat layer is provided to protect the heat-sensitive recording layer, and an undercoat layer consisting of a single layer or multiple layers of pigment or resin is provided between the heat-sensitive recording layer and the support. Various known techniques can be used. The coating amount of the heat-sensitive recording layer is determined by the amounts of the dye precursor and color developer, which are color forming components, and is usually 0.1 to 1.5 mm. , O
g/rrf is appropriate. Further, the amount of the color developer added is 5 to 400% by weight based on the dye precursor, and a particularly preferable addition amount is 20 to 300% by weight. The compound of the present invention is added in an amount of 5 to 400% by weight based on the color developer, and a particularly preferable addition amount is 20 to 300% by weight.

【Example】

Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight. Example 1 Preparation of heat-sensitive recording material (A) Preparation of heat-sensitive coating liquid Dye precursor 3-dibutylamino-6-methyl-7
- 35 parts of anilinofluorane and 80 parts of a 2.5% polyvinyl alcohol aqueous solution were ground in a ball mill for 24 hours to obtain a dye dispersion. Next, 40 parts of 2,2-bis(p-hydroxyphenyl)propane and 60 parts of a 2.5% polyvinyl alcohol aqueous solution were ground in a ball mill for 24 hours to obtain a color developer dispersion. 1-Cinnamyloxy-4ethoxybenzene (compound of Example 1, melting point 106°C) 5
0 part was ground with 120 parts of a 2.5% polyvinyl alcohol aqueous solution in a ball mill for 24 hours to obtain a dispersion of the compound of the present invention. After mixing the above three types of dispersions, the following were added and mixed well while stirring to prepare a heat-sensitive coating liquid. 50% calcium carbonate dispersion 100 parts 40% zinc stearate dispersion 25 parts 10% polyvinyl alcohol aqueous solution 185 parts water
280 copies (B) Preparation of heat-sensitive coated paper A coating liquid consisting of the following composition is smeared on base paper with a basis weight of 40 g/rrf to a solid content of 9 g/r+f, and dried to create heat-sensitive coated paper. did. Calcined kaolin 100 parts Styrene-butadiene latex 50% aqueous dispersion ・24 parts water
200 copies (C) Preparation of heat-sensitive recording material The heat-sensitive coating liquid prepared in (A) was smeared on the surface of the heat-sensitive coating paper prepared in (B) so that the solid content coating amount was 4 g/rrf, and dried. A heat-sensitive recording material was prepared. Example 2 Thermal reaction was carried out in the same manner as in Example 1 except that 1-cinnamyloxy-4-ethoxybenzene in Example 1 was replaced with 1-cinnamyloxy-4n-propoxybenzene (compound of Example 2, melting point 103°C). Created recording materials. Example 3 Same as Example 1 except that 1-cinnamyloxy-4-ethoxybenzene in Example 1 was replaced with 1-n-butoxy-4-cinnamyloxybenzene (compound of Example 4, melting point 102°C). A heat-sensitive recording material was prepared. Example 4 Same as Example 1 except that 1-cinnamyloxy-4-ethoxybenzene in Example 1 was replaced with 1-cinnamyloxy-4n-octyloxybenzene (compound of Example 40, melting point 93°C). A thermosensitive recording material was created. Comparative Example 1 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that 1-cinnamyloxy-4ethoxybenzene in Example 1 was omitted. Comparative Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that N-hydroxymethylstearamide was used in place of 1-cinnamyloxy-4ethoxybenzene in Example 1. Comparative Example 3 In place of 1-cinnamyloxy-4ethoxybenzene in Example 1, 4-cinnamyloxyanisole (compound described in JP-A No. 63-21.181, melting point 9) was used.
A heat-sensitive recording material was prepared in the same manner as in the example except that the temperature was 1°C. Comparative Example 4 In place of 1-cinnamyloxy-4ethoxybenzene in Example 1, 1-chloro-4-cinnamyloxybenzene (compound described in JP-A-63-21.1.81°, melting point 107°) was used. A heat-sensitive recording material was prepared in the same manner as in Example except that C) was used. Comparative Example 5 In place of 1-cinnamyloxy-4ethoxybenzene in Example 1, 4-cinnamyloxytoluene (compound described in JP-A-63-211.8F, melting point 78°C) was used.
) A heat-sensitive recording material was prepared in the same manner as in the example except that the material was used. Evaluation 1 The heat-sensitive recording materials obtained in Examples 1 to 4 and Comparative Examples 1 to 5 were calendered so that the Beck smoothness of the heat-sensitive coated surface was 400 to 500 seconds, and then subjected to a facsimile IJ tester TH manufactured by Okura Electric Co., Ltd. - A printing test was conducted using PMD. A thermal head with a dot density of 8 dots/mm and a head resistance of 185 Ω was used, with a head voltage of 12 V and a pulse width of 0.
．． Printing was performed by applying current for 5 and 07 milliseconds, and the color density was measured using a Macbeth RD-918 reflection densitometer. The results are shown in Table 1. (Margins below) Print samples obtained from Table 1゜Coloring sensitivity evaluation 2 evaluation] at 40℃, 90%
Macbeth RD
-Measurement was made using a Model 918 reflection densitometer. The results are shown in Table 2. (Margins below) Table 2゜Image storage test evaluation 3 The print sample obtained in evaluation 1 was left at 60℃ under dry conditions for 24 hours, and the image area density was adjusted to Macbeth RD-9.
It was measured using a 18-inch reflection densitometer. The results are shown in Table 3. (Margins below) Table 3゜Image preservation test

【Effect of the invention】

As is clear from the examples, by containing the compound of the present invention, it was possible to obtain a heat-sensitive recording material with excellent thermal responsiveness, high optical density with the same applied energy, and high color development sensitivity. Furthermore, a heat-sensitive recording material with excellent image storage stability could be obtained.

Claims (1)

[Claims] 1. 1-phenyl-3-x-alkoxyphenyloxy-1-propene in a heat-sensitive recording material containing an electron-accepting compound that reacts with a normally colorless to light-colored dye precursor upon heating to cause the dye precursor to develop color. (However, x is o,
It indicates either the m or p position, and the alkoxy group is a group having 2 or more and 8 or less carbon atoms. ) A heat-sensitive recording material characterized by containing.