JPH0284381A - Thermal recording material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention mainly uses a colorless or light-colored organic dye, generally called a leuco compound, and a right n-acid such as a phenol compound that develops a color by reacting with the leuco compound. The present invention relates to a heat-sensitive recording material as a component, and particularly relates to an improvement of a heat-sensitive recording material that improves the matching property with a thermal head.

[Prior Art 10 A thermosensitive recording material containing an icos compound and an organic acid is already known, for example, from Japanese Patent Publication No. 14039/1983. This recording paper is based on the principle that thermal energy is applied to the recording layer to soften or melt the leuco compound and organic acid, and the two color-forming components come into contact with each other to cause a color reaction. used in

In recent years, as the demand for heat-sensitive recording media has increased, there has been an increasing demand for improved quality. The required characteristics of a thermal recording medium include the fact that there is no sticking during printing, and that there is little residue adhering to the thermal head. In addition to these required properties, as recording speeds increase, the recording layer of a thermosensitive recording medium is required to have smoothness.

The reason for this is that when the friction between the recording layer of the thermosensitive recording medium and the thermal head is large, the printed image shrinks. Therefore, it is important to improve the slipperiness between the recording layer and the thermal head during high-speed recording. It is essential for

In order to improve the head matching properties, attempts have been made to add metal salts of higher fatty acids, typified by zinc stearate, and various waxes.

[Problems that R-mei aims to solve] However, the method of using metal salts of higher fatty acids as a lubricant improves the head matting property, but has the drawback of increasing background fog, and the method of adding waxes. The disadvantage of this method is that the amount of debris that adheres to the head increases.

Therefore, it is an object of the present invention to provide a heat-sensitive recording medium suitable for high-speed recording, which achieves both improvement in head matching properties that could not be achieved with these conventional methods and other required characteristics.

[Means for Solving the Problems] Briefly, the present invention provides a heat-sensitive recording material mainly composed of a leuco compound and an aqueous acid that develops a color corresponding to the leuco compound. It is constructed to contain boron nitride.

The present invention will be described in detail below.

The heat-sensitive recording material of the present invention comprises a support coated with a heat-sensitive recording layer containing a leuco compound, an organic acid as a color developer, a binder, and boron nitride.

Further, it is a heat-sensitive recording material in which a layer containing boron nitride is coated on a heat-sensitive recording layer that does not contain boron nitride.

The boron nitride used in the present invention is a known hexagonal crystal system wireless compound, and compared to conventionally used lubricants,
Although it significantly improves head matching performance,
The reason for this is that the melting point is 3000℃ (sublimation occurs at this temperature)
This is thought to be because the smoothness is not lost during recording. Also, the characteristics of the pond as a heat-sensitive recording medium,
'l Concentration, hold? It also has properties that cause no problems such as background fogging and discoloration after '7.

This boron nitride content is 1% of the total solid content of the heat-sensitive recording layer.
~20% by weight is preferred.

Further, the boron nitride content of the layer containing boron nitride provided on the heat-sensitive recording layer may be 1 to 30% by weight of the total solid content of the layer.

Leuco compound The leuco compound used in the present invention is a colorless or light-colored substance that develops color by reacting with an organic acid, and includes triphenylmethane type, triphenylmethane phthalide type, fluoran type, leuco auramine type, and dinoenylmethane type. , phenothiazine series, phenoxazine series, spiropyran series, impilin series, indigo series, and various other derivatives. Preferred leuco compounds include, for example, crystal violet lactone, 3-diethylamino-6-methyl-
7-anilinofluorane, 3-(N-ethyl-P-toluidino)-6-methyl-7-anilinofluorane, 3-
Diethylamine-6-methyl-7-(ortho, para-dimedylanilino)fluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-(N-cyclohexyl-N-medylamino)-6-methyl -7-anilinofluoran, 3-diethylamino-7-(ortho-chloroanilino)fluoran, 3-diethylamino-7-(meth-trifluoromethylanilino)fluoran, 3-diethylamine-6-methyl-chlorofluoran, 3 -diethylamino-6-medylyfluorane, 3-(N-isoamyl-N-edylamino)-6-medyly-7-anilinoflurane, 3-dibutylamino-6-methyl-7-
Anilinofluorane is mentioned.

Organic acid (or ester thereof) The organic acid used in the present invention is a substance that is solid at room temperature and becomes a color developer when it comes into contact with a leuco compound when heated, and includes various phenolic substances, fatty acids, aromatic compounds, etc. There are carboxylic acids. Examples include gallic acid, salicylic acid,
1-hydroxy-2=naphthoic acid, 0-hydroxyan Q
6-acid, m-hydroxybenzoic acid, 2-hydroxy-p-
Toluic acid, 3.5-xylenol, thymol, p-t
Crt-butylphenol, 4-hydroxyphenoxide, methyl-4-hydroxybenzoate, 4-hydroxyacetophenone, α-naphthol, β-naphthol, catechol, resorcinol, hydroquinone, 4-ter
t-Octylcatechol 4,4''-sec-butylidenephenol, 2.

2-dihydroxydiphenyl, 2.2=-methylenebis(4-methyl-5-jert-butylphenol),
2.2-bis(4-hydroxyphenyl)propane (
Other names: bisphenol A), 4,4-isopropylidene-bis(2-tert-butylphenol), pyrogallol, phloroglucin, phloroglucin carboxylic acid,
p-methylphenol, p-phenylphenol, 4.
4-Cyclohexylidene diphenol, 4,4'-isopropylidene dicatechol, 4,4-benzylidene diphenol, 4,4-isopropylidene bis(2-chlorophenol), 3-phenylsalicylic acid, 3,5 −
Di-tert-butylsalicylic acid, 1-oxy-2-nano-1-technical acid, gallic acid ester, salicylic acid ester,
p-hydroxybenzoic acid ester, 4-hydroxyphthalic acid ester, 2-(4-hydroxyphenyl)-2(
3,-hydroxyphenyl)propane, 4.

Examples include 4'-dihydroxy-3,3-diisopropyldiphenyl-2,2'-propane.

Stone agent The binder used in the present invention mainly consists of a water-soluble binder, which separates the coloring agent dispersed in fine particles from each other and prevents it from solidifying. Loose, hydroxyethyl cellulose, polyacrylic acid, casein, gelatin, starch and their derivatives are burned.

Additives The heat-sensitive recording layer of the present invention may contain other additives as necessary, such as inorganic materials such as clay, calcium carbonate, synthetic silica, aluminum hydroxide, talc, titanium oxide, zinc oxide, etc., or pigments. , antioxidant for storage stability, ultraviolet absorber, water resistant agent to improve water resistance, phenol (i4
fats, surfactants, conventionally used waxes,
Metal salts of higher fatty acids, etc. can be added.

Production of heat-sensitive recording material The coating material for the heat-sensitive recording layer of the present invention contains the above-mentioned leuco compound 1, as well as
Separately from the right b1 acid, boron nitride, pigment if necessary,
It is generally prepared by pulverizing and dispersing additives such as a sensitivity modifier in an aqueous medium containing an appropriate concentration of a binding agent such as polyvinyl alcohol using a ball mill or a sand grinder. It is advantageous in terms of color development efficiency to make each 1iIS component as fine as possible, and preferably to have a particle size of 0.5 to 3 μm.

The heat-sensitive paint thus obtained is applied to the support described below and dried to obtain the heat-sensitive recording material of the present invention.

Further, boron nitride used in the present invention can also be contained in an overcoat paint for a heat-sensitive recording layer that does not contain boron nitride.

Coating can be done using a regular blade coater, air knife coater,
This can be done using a bar coater, reverse roll coater, or the like.

The support used in the present invention generally includes high-quality paper,
Papers such as medium-quality paper and coated paper are used, but other materials such as glass uA fiber sheets, plastic sheets, and film laminated papers can also be used as the support.

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

However, the technical scope of the present invention is not limited to these examples.

a) Production Example 1 of Heat-Sensitive Recording Body Liquids A and B having the following compositions were prepared by separately dispersing them in pane 1 using a shaker (manufactured by Toyo Seiki) for 10 hours.

Aa: Leuco dye 3-dibdelamino-6-methyl-7-anilinofluorane 5g polyvinyl alcohol 12% solution 359 water
509B liquid bisphenol A 15g boron nitride 3g polyvinyl alcohol 12% liquid 359 water
47
Next, add 100 g of solution A, 100 g of solution 8, 50 g of 12% polyvinyl alcohol solution, and 159 g of synthetic silica P-832 (manufactured by Mizusawa Chemical). Add 609% of water and mix and stir to prepare a coating solution. Next, apply this coating solution to the surface of 50g/Tlt high-quality paper using a Mayer bar so that the coating amount after drying is 89%.
/TIt was coated and dried, and the heat-sensitive recording paper was 151.

Comparative Example 1 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the boron nitride of liquid B used in Example 1 was not used.

Comparative Example 2 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that polyethylene wax was used instead of boron nitride in the formulation of liquid B used in Example 1.

Comparative Example 3 A thermosensitive recording paper No. 19 was prepared in the same manner as in Example 1, except that zinc stearate was used instead of boron nitride in the formulation of liquid B used in Example 1.

Example 2 Solution C: Polyvinyl alcohol 12% solution 803 Synthetic silica (P-832) 10!7 Boron nitride 3 Shimedil cellulose 5% solution 219 Water
50g
The above liquid C was applied onto the heat-sensitive recording layer of the heat-sensitive recording paper obtained in Comparative Example 1 using a Mayer bar in an amount of 3 g/bottom after drying, and dried to obtain a heat-sensitive recording paper.

Comparative Example 4 A thermosensitive recording paper was obtained in the same manner as in Example 2, except that polyethylene wax was used instead of boron nitride in the formulation of liquid C used in Example 2.

In the above Examples and Comparative Examples, the heat-sensitive recording paper No. 17 was surface-treated with a test super calender so that the recording surface had a Bekk smoothness of 500 seconds.

b) Testing of heat-sensitive recording bodies The following tests were conducted for each of the heat-sensitive recording bodies tested, and the results are not shown in the table.

Test method (1) Image density “T-216-8MPDI
(Solid printing was performed using a Kyocera (Kikuso) under the conditions of a printing power of 0.70 W/dat and a pulse width of 0.8 ms, and the print density and background density at that time were measured using a Macbeth densitometer Its-914.

(2) Image shrinkage 35℃, 85% R1+, IF-1000 (Matsushita Electric Transmission)
manufactured by).

One sheet of Image 9 Institute of Electronics Engineers N (12 Jar!-) was printed, and the shrinkage (m) of the image was measured.

(3) Sticking test Printing was performed using UF-1000 (as described above) in an atmosphere of 0° C., and the presence or absence of sticking was examined at that time.

(4) Dust adhesion test 3m with UF-1000 (described above) in an atmosphere of 20℃
The dirt around the thermal head was visually determined by m-solid printing.

Table [Effects of the Invention] As described above, the heat-sensitive recording material of the present invention improves the slipperiness of the heat-sensitive recording layer, improves the head matching property, can cope with high-speed recording, and prevents sticking and debris adhesion. The required characteristics of Haku as an S thermosensitive recording material are also excellent.

Claims (1)

[Scope of Claims] 1. In a heat-sensitive recording material provided with a heat-sensitive recording layer containing a leuco compound, an organic acid that reacts with the leuco compound to develop a color, and a binder, the heat-sensitive recording layer is provided on a support. A heat-sensitive recording material characterized by containing boron nitride in the recording layer. 2. In a heat-sensitive recording material in which a heat-sensitive recording layer containing a leuco compound, an organic acid that reacts with the leuco compound to develop a color, and a binder is provided on a support, nitriding is applied on the heat-sensitive recording layer. A heat-sensitive recording material characterized by having a layer containing boron.