JPS5834316B2 - heat sensitive recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a colorless or light-colored leuco dye as a heat-sensitive coloring component, and a colorless or light-colored leuco dye that is colored by heating.
The present invention relates to a heat-sensitive recording material using an acidic substance.

A heat-sensitive recording material is a recording material formed on the surface of a so-called heat-sensitive color-forming component support, such as paper, which develops color by heating, and a thermal printer with a built-in thermal head is used for heating.

The heat-sensitive recording method using the above-mentioned recording materials is used to copy books, documents, etc., and is also used to record the output of computers, facsimiles, measuring instruments, etc., and the heat-sensitive coloring component of the recording material is A heat-sensitive coloring layer containing a colorless or light-colored leuco dye having a lactone, lactam, or spiropyran ring and an acidic substance such as an organic acid or a phenolic substance is formed on a support, and the color tone is clear. It is widely used because it can withstand long-term use and has excellent storage stability.

However, in recent years, there has been a demand for higher speeds and higher densities of the output machines, but the heat-sensitive recording materials using the color-forming components cannot fully satisfy these demands.

Therefore, conventionally, heat sensitivity sensitizers such as stearamide, lyrunamide, laurylamide, myristylamide, hydrogenated bovine fatty acid amide, palmitamide, oleic acid amide, rice sugar fatty acid amide, coconut fatty acid amide, or these are added to the heat-sensitive coloring layer. Attempts have been made to increase the thermal sensitivity of thermosensitive recording and speed up recording using fatty acid amide compounds such as methylolated fatty acid amide, methylene bis stearamide, and ethylene bis stearamide. During long-term recording, the thermal head often needs to be cleaned because debris adheres to the thermal head, causing a sticking phenomenon and impeding the running performance of the head, which greatly impairs the clarity of colored images. Ta.

Furthermore, conventional heat-sensitive recording materials still have problems that require improvement, such as pressure coloring due to rubbing or pressure, and fogging during storage.

The purpose of the present invention is to solve these conventional drawbacks. Specifically, even during high-speed recording and long-time recording, the sharpness of the colored image may be reduced, and debris adhesion and sticking may occur, causing the head to run. An object of the present invention is to provide a heat-sensitive recording material that does not impede sexual performance.

Furthermore, pressure coloring, during storage? An object of the present invention is to provide a heat-sensitive recording material that does not cause fogging.

As a result of repeated research in view of the above object of the present invention, a thermosensitive coloring layer containing a colorless or light-colored leuco dye as a thermosensitive coloring component and an acidic substance that causes the leuco dye to develop color when heated was formed on a support. In heat-sensitive recording materials,
It has been found that the above-mentioned conventional drawbacks can be solved at once by containing a compound represented by the following general formula (A'l) and a compound represented by the two general formulas (B) in the heat-sensitive coloring layer. , we have achieved the present invention.

General formula (A) (R1 and R2 are alkyl groups having 10 to 30 carbon atoms) General formula CB] R3: Alkyl groups having 1 to 30 carbon atoms R4, R5: Hydrogen, halogen, lower alkyl group and lower alkyloxy group Any one of them n: O or I R6, R8: Any one of an alkyl group having 1 to 30 carbon atoms and a substituted or unsubstituted phenyl group R7, R9: Any one of hydrogen, halogen, and lower alkyl group 1) By containing the compound (A') represented by the above general formula and [B], the conventional drawbacks could be significantly improved.

That is, by adding a combination of the compounds shown in [A] and CB) to the heat-sensitive coloring layer, it is possible to increase the thermal sensitivity and form a clear colored image with a relatively small amount of thermal energy. It was possible to obtain a heat-sensitive recording material that prevents color development due to pressure and adhesion of residue to the heat-sensitive head, can withstand long-term printing, and has excellent running properties.

Furthermore, when the heat-sensitive recording material was stored for a long period of time, no capri was generated at all, and it could be used for a long period of time.

The detailed reason why such an effect was obtained in the present invention is unknown, but in order to solve these problems, it is necessary to have a material that has a large melting point lowering effect and compatibility. low viscosity when dissolved, good crystallinity, resistance to water, no coloration,
Requirements include high stability, not interfering with the adhesion of the heat-sensitive coloring layer, not developing color before recording, and good lubricity. Among these, in particular, leuco dyes, melting point lowering effects on phenolic substances, and compatibility with leuco dyes and phenolic substances. Fermentability is said to be an important factor for increasing the speed, and the compounds represented by the general formulas [A] and CB) appear to fully satisfy this condition.

In addition, the compound represented by the general formula [A] in particular has a strong lubricity effect and improves the lubricity of the surface of the heat-sensitive coloring layer, thereby preventing dregs adhesion and sticking and improving the runnability of the head. I think that the.

To explain the present invention more specifically, the general formula CB'
Compounds (1) to (3) represented by l are each independently,
Alternatively, they may be used in combination, and the amount used is 0.000 parts by weight per 1 part by weight of the leuco dye contained in the heat-sensitive coloring layer.
It is preferable to use 5 to 5 parts by weight; if it is less than 0.5 parts by weight, the improvement in thermal sensitivity will not be sufficient, and if it is more than 5 parts by weight, no further effect can be expected. Compound represented by general formula [A] Usage is before.

The amount is preferably 0.2 to 3 parts by weight per 1 part by weight of the compound of the general formula CB).

If it is less than 0.2 parts by weight, the recording suitability will not be improved sufficiently, and if it is more than 3 parts by weight, no further effect can be expected.

In the compound of the general formula CA) used in the present invention, R1 and R2 in the above formula are decyl, undecyl, dodecyl,
Examples include alkyl groups having 10 to 30 carbon atoms such as tridecyl, tetradecyl, pencudecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl, and those having 16 to 22 carbon atoms are particularly preferred.

Among the N-substituted acid amides represented by CB'l, those represented by include, for example, N-stearylbenzamide, N-palmityl-2-chloropenzamide, N-stearyl-2-methoxybenzamide, N- Stearyl-4-methylbenzamide, N-palmityl-2,4-
Dimethylbenzamide, N-behenylbenzamide, N
Examples include -behenyl-2-methylbenzamide, N-stearylphenylacetylamide, and N-behenylphenylacetylamide, and synthesis examples of the main ones among these are shown below.

Synthesis Example N-stearylbenzamide: Stearylamine 279 is suspended in 100 d of toluene, benzoyl chloride 13.9 is gradually added at 70°C, and heated to 110°C.

It was kept for about 20 hours until the generation of hydrogen chloride gas stopped, cooled, filtered, then neutralized with sodium hydroxide and washed with water to obtain a crude product, which was recrystallized with alcohol and had a melting point of 85 to 87°C.
A white crystalline substance is obtained.

N-Stearyl phenylacetylamide: 27 g of stearylamine was dispersed in toluene 1001111 in a suspension state, and 14 g of phenylacetic acid chloride was gradually added at 70'C, the temperature was raised to 90°C, the mixture was reacted for 10 hours, and after cooling, filtration,
Neutralize with sodium hydroxide and wash with water to obtain a purified product, which is further recrystallized using alcohol to obtain white crystals with a melting point of 93 to 94°C.

Among the acid amide substituted products represented by the general formula CB), further (
2) and (3), for example, N
-Cyclohexylacetamide, N-cyclohexylpropionamide, N-cyclohexylstearamide, N-cyclohexylbenzamide, N-cyclohexyl-2-methylbenzamide, N-cyclohexyl-
2-chlorobenzamide, N-cyclohexyl-2,4
-Dimethylbenzamide, N-cyclohexylpalmitic acid amide, N-(2-chlorohexyl) palmitic acid amide, N-(2-methylcyclohexyl) stearic acid amide, N-stearylhexahydrobenzamide, and the main ones are A synthesis example is shown below.

Synthesis example N-cyclohexyl stearic acid amide: Dissolve 10 g of cyclohexylamine in 80 rIL of toluene,
Cool to below 0°C and add 30g of stearic acid chloride to 1
If you add it over time, it will solidify completely.

After keeping at 30℃ for 2 hours, filtering, neutralizing with alkaline alcohol, washing with water, and recrystallizing with alcohol, the melting point is 9.
White needle-like crystals with a temperature of 3.5-94.5°C are obtained.

N-cyclohexylbenzamide: 18.9 cyclohexylamine was added to 50 rIll of benzene.
benzoyl chloride 20 at below 40°C.
When g is gradually added, white smoke is generated and a white precipitate is deposited.

After stirring this for 1 hour, it is made alkaline with pyridine, filtered, and then recrystallized using a methanol:ethanol=1:1 yeast to obtain white needle-like crystals with a melting point of 144-145°C.ON-stearylhexahydropenzamide: Stearylamine 27.9 was fermented in 100 mJ of benzene at 30'C, hexahydrobenzoic acid chloride 20& was added at 0 to 10°C over 1 hour, the temperature was raised to 60°C, kept for 3 hours, cooled, and then filtrated. , neutralize with alkaline alcohol, wash with water, and recrystallize the furnace material with ethanol to obtain a melting point of 89-9.
White crystals of 0'C are obtained.

In addition to the compounds represented by the above-mentioned general formulas (A'l and CB), leuco dyes, acidic substances, and binders commonly used in this type of field are used in the heat-sensitive coloring layer.
Specific examples are shown below.

■ Leuco dye: (a) Leuco base of triphenylmethane dye:
A compound represented by the following general formula: In the formula, Rx, Ry and R2 are hydrogen, hydroxyl group, halogen, alkyl group, nitro group, amino group, dialkylamino group, monoalkylamino group, or allyl group.

Specific examples of the above compounds are as follows.

3.3-bis(p-dimethylaminophenyl)-phthalide, 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(p- dimethylaminophenyl)-6-dibutylaminophenyl, 3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(p-dibutylaminophenyl)phthalide.

(b) Leuco base of fluoran dye: compound represented by the following general formula: In the formula, Rx, R, and R2 are the same as in (a) above.

Specific examples of the above compounds are as follows.

3-cyclohexylamino-6-chlorofluorane, 3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluorane, 3-dimethylamino-5,7-dimethylfluorane, 3-diethylamino-7-methylfluorane 0 (c) Fluoran dye: 3-diethylamino-6-methyl-7 -chlorofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2-(N-(3'-1-lifluoromethylphenyl)amine)-6-dinithylaminofluorane, 2-( 3,6-bis(diethylamino)9-(o-chloroanilino)xantylbenzoic acid lactam).

) A lactone compound represented by the following general formula: in the formula R1
and R2 represents hydrogen, a lower alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted phenyl group, a cyanoethyl group, or a β-halogenated ethyl group, or R1 and R2 are combined and CH2+4° -(CH
2chi, also represents ÷CH2+20+-CH2chi, and R
3 and R4 represent hydrogen, a lower alkyl group, an alkyl group, an amyl group, or a phenyl group, any one of R3 and R4 is hydrogen, and Xl, X2 and X3 are hydrogen, a lower alkyl group, a lower alkoxyl group, represents a halogen atom, a halogenated methyl group, a nitro group, an amino group, or a substituted amino group, X4 represents hydrogen, a halogen, a lower alkyl group or a lower alkoxyl group, and n represents O or an integer from 1 to 4. .

Specific examples of the above compounds are as follows.

3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-57-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-( 2'-methoxy-57-nitrophenyl)
Phthalide, 3- (2'-human-oxy4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl) phthalide, 3- (2'-methoxy-4'-dimethylaminophenyl) - 3-(2'-hydroxy-4'-chloro-57
-methylphenyl)phthalide.

2. Acidic substances diboric acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid, benzoic acid, stearic acid, gallic acid, salicylic acid, 1-hydroxy-2 naphthoic acid, o-hydroxybenzoic acid, m-hydroxybenzoic acid acid, 2-hydroxy-p
-Toluic acid, 3,5-xylenol, thymol, p-
ter t-butylphenol, 4-humanized xyphenoxide, methyl-4-humanized xybenzoate, 4-hydroxyacetophenone, α-naphthol, β-naphthol, catechol, redulucin, hydroquinone, 4-t
ert-octylcatechol, 4,4'-5ec-
Butylidenephenol, 2,2'-dihydoxydiphenyl, 2,2'-methylenebis(4-methyl-6ter)
t-butylphenol), 2,2-bis(4-hydroxyphenyl)furopane, 4,4'-improhyritenebis(2-tert-butylphenol), 4,4'5e
c-butylidene diphenol, pyrogallol, phloroglucin, phloroglucin carboxylic acid.

3. Binders such as wood vinegar-based materials such as polyvinyl alcohol, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch, gelatin, etc.
Alternatively, aqueous emulsions such as polystyrene, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, etc. can be used as the binder.

In the heat-sensitive recording material of the present invention, fine powders such as calcium carbonate, silica, alumina, magnesia, curcum, barium sulfate, and aluminum stearate are further added to the heat-sensitive coloring layer to improve the clarity of the colored image. Furthermore, the running properties of the thermal head can be further improved by adding a lubricant such as linseed oil, tung oil, wax, paraffin, polyethylene wax, or chlorinated paraffin.

Examples of the present invention are shown below.

Example 1 Dispersions A and B were prepared by mixing the following components for 10 hours using a ball mill.
were further mixed to prepare a thermosensitive coloring layer forming solution.

Dispersion'' A. Dispersion part) 2 (
N-(3'-)lifluoromethyl 6.2phenyl)amino)-6-dinithylaminofluoran polyvinyl alcohol (10% aqueous solution > 23°O
Water 20.8 Dispersion B Bisphenol A 23.0
Oxidized starch 30 aluminum stearate 2. ON-stearylphenacetamide 8.6 distearyl 4,5
-Epoxy 4.3 Chlohexene-1,2-dicarboxylate water 9.1
The thermosensitive color forming layer forming liquid prepared as above was applied onto the surface of high quality paper (5]9/m) using a wire bar and dried to form a heat sensitive color forming layer with a coating weight of 5-89/@. A heat-sensitive recording material of the present invention was obtained.

When the recording material thus obtained was printed at a temperature of 120° C. using a thermal printer equipped with a built-in thermal head, a clear black image was quickly obtained.

Furthermore, regarding recording suitability, we conducted a 24-hour continuous test on running performance with a thermal head using an Oki Electric facsimile machine, and found that no scum adhesion or sticking occurred, and the running performance with the head was extremely good, making it possible to record for long periods of time. Clear recorded images were always obtained, demonstrating its excellent recording suitability.

Furthermore, there was no rubbing of non-image areas or color development due to pressure.

Further, when a forced aging test was conducted by leaving the product at a temperature of 60'C for 24 hours, no fogging was observed and the product had excellent storage stability.

Example 2 Cyclohexyl stearic acid amide was used instead of N-stearylphenacetamide used in Example 1, and distearyl-4,5-epoxycyclohexene-1
, dibephenyl-4 instead of 2-dicarboxylate
, 5-epoxycyclohexene-1,2-dicarboxylate was prepared and printed in the same manner as in Example 1. A clear black image was quickly obtained.

The recording suitability, pressure color development, and storage stability were also tested in the same manner as in Example 1, and all showed excellent results.

Examples 3 to 7 In place of N-stearylphenacetamide used in Example 1, N-stearylbenzamide N-stearyl-2-methoxybenzamide N-behenyl-2-methylbenzamide N-Schiff 40hexylbenzo A heat-sensitive recording material was prepared using amide N-stearyl hexahydrobenzamide and printed in the same manner as in Example 1, and a clear black image was quickly obtained.

Further, similar to Example 1, recording suitability, pressure color development, and storage stability were tested, and as in Example 1, excellent results were shown in all of them.

Claims (1)

[Scope of Claims] 1. A heat-sensitive recording material in which a heat-sensitive coloring layer containing a colorless or light-colored leuco dye as a heat-sensitive coloring component and an acidic substance that causes the leuco dye to develop color when heated is formed on a support, The following general formula (A'
A heat-sensitive recording material comprising at least one of a compound represented by 1 and a compound represented by general formula CB). General formula [A] (R1, R2: alkyl group having 10 to 30 carbon atoms) (R3
: Alkyl group having 1 to 30 carbon atoms R4, R5: Any one of hydrogen, halogen, lower alkyl group, and lower alkyloxy group n: O or I R6, R8: Alkyl group having 1 to 30 carbon atoms and substitution or any one of unsubstituted phenyl groups (R7, R9: any one of hydrogen, halogen, and lower alkyl group)