JPH0230584A - Thermosensitive recording material - Google Patents

Abstract

PURPOSE:To furnish excellent sensitivity and retention stability by incorporating deoxyanisoin as a color accelerator in a thermosensitive recording layer. CONSTITUTION:Coating in a thermosensitive recording layer is prepared as follows. Abovementioned leuco compound and organic acid are independently, together with deoxyanisoin and additives such as pigment, sensitivity conditioner, etc., if necessary, ground to be dispersed in an aqueous medium incorporating a binding agent such as polyvinyl of a suitable density or the like. Thereafter, the dye dispersion liquid and the organic acid dispersion liquid are mixed by stirring. It is favorable from a stanpoint of color efficiency to grind each component material as fine as possible, and the component materials are preferably ground to 0.3 to 3mum in particle size. The thermosensitive coating thus obtained is applied to a base material, which is dried to obtain a thermosensitive recording material.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention uses a colorless or light-colored organic dye generally called a leuco compound, and an organic acid such as a phenol compound that develops a color by reacting with the leuco compound. This invention relates to improvements in heat-sensitive recording materials.

[Prior Art] A thermosensitive recording paper containing a leuco compound and an organic acid is already known, for example, from Japanese Patent Publication No. 14039/1983. This recording paper applies thermal energy to the recording layer to soften or melt the leuco compound, organic acid, and binder.
It is based on the principle of causing a color reaction by bringing the two color components into contact with each other, and has recently been used in various fields such as printers and facsimile machines. The recording characteristics of this recording paper differ depending on the application, but in order to increase the recording speed, for example, it is necessary to improve the recording device and to promote the color development of the recording paper itself.

A commonly used method for promoting color development is to include a low melting point substance in the recording layer.

Low melting point substances, such as color accelerators or sensitizers,
In Japanese Patent Publication No. 43-4160, urea, phthalic anhydride,
Ace1 to anilide, and in JP-A No. 19231/1989, paraffin wax, carnauba wax, beeswax, real wax, higher fatty acids, and higher fatty acid esters are
No. 9-17748 discloses zarydylic acid, anisic acid, monophenylnisder phthalate, and monobenzyl phthalate, and in recent years fatty acid amides have also been widely used as color accelerators. In other words, the special public official 1971-
No. 27599 describes the sensitizing effect of fatty acid amide by combining paraffin or microcrystalline wax with fatty acid amide, and JP-A-54-139740 also describes the sensitizing effect of fatty acid amide such as stearic acid amide and oleic acid amide. Sensitive effects have been described and are well known.

Further, terphenyl is disclosed in JP-A-57-27785, and parahenzilbifel is disclosed in JP-A-60-82382.

[Problems to be Solved by the Invention] However, the effects of conventional color development accelerators cannot be said to be sufficient, and there has been a strong demand for a technique that provides even better color development. The present inventors confirmed the effects of these conventional color development accelerators, and as a result of wide and deep studies in order to find substances with even better properties, they discovered a new color development accelerator that has remarkable effects. Based on this knowledge, the present invention was developed to 17i.

An object of the present invention is to provide a heat-sensitive recording material that provides better sensitivity and storage stability than conventional heat-sensitive recording materials using color development accelerators.

[Means for IC that solves the problems] That is, the present invention provides a heat-sensitive recording material mainly composed of a leuco compound and an organic acid that develops color by reacting with the leuco compound, which promotes color development in the heat-sensitive recording layer. It is constructed to contain deoxyanisoin as an agent.

The present invention will be explained in detail below.

The heat-sensitive recording material of the present invention comprises (a) a heat-sensitive recording layer containing a compound, an organic acid as a color developer, an adhesive, and a compound represented by the following structural formula as a color development promoter, coated on a support. It is made of manufactured materials.

Deoxyanisoin, the color development accelerator used in the present invention, has a melting point of 109 to 112°C, and is excellent in the effect of promoting color development, as well as having other properties as a heat-sensitive recording material, such as a It also has excellent properties in terms of background fogging and discoloration.

The content of this deoxyanisoin is preferably 1 to 50% by weight of the total solid content of the heat-sensitive recording layer from the viewpoint of promoting color development.

Further, the color development accelerator of the present invention can be contained in the recording layer in combination with a known color development accelerator.

The leuco compounds used in the present invention are colorless to light-colored substances that develop color by reacting with organic acids, such as 1-diphenylmethane, triphenylmethane phthalide, fluoran, leuco auramine, diphenylmethane, and phenothiazine. series, phenoxazine series, spiropyran series,
Examples include various derivatives such as impilin derivatives and indigo derivatives. Preferred leuco compounds include, for example, crystal violet lactone, 3-diethylamine-6-medy-7-anilinofluorane, 3-(N-ethyl-P-
1-luidino)-6-medy-7-anilinofluoran, 3-diethylamine-6-methyl 7-(ortho, valadimedylanilino)fluoran, 3-piperidino-
6-Methyl-7-anilinofluorane, 3-(N-cyclohexyl-N-medylamino)-6-methyl-7-
Anilitufluoran, 3-diethylamine-7-(ol-1-chloroanilino)fluoran, 3-diethylamine-7-(meth-1-helifluoromethylanilino)fluoran, 3-diethylamine-6-methyltyl-fluoran, 3-diethylamine-7-(meth-1-helifluoromethylanilino)fluoran, (N-isoamyl-N ethylamino)-
Examples include 6-methyl-7-anilitofluorane and 3-dibdelamino-6-medy-7-anilinofluoran.

The organic acid used in the present invention is a substance that is solid at high temperatures, melts when heated, and becomes a color developer when it comes into contact with a leuco compound, and includes various phenolic substances, fatty acids, aromatic carboxylic acids, etc. . Examples include gallic acid, zarydylic acid, 1-hydroxy-2-naphthoic acid, 0-hydroxybenzoic acid, m-hydroxybenzoic acid, 2-hydroxy-p-toluyl M, 3.5-xylenol, dimol, p
-tert-butylphenol, 4-hydroxyphenoxide, methyl-4-hydroxybenzo = 6 to Ni 1, 4-hydroxyacetophenone, α-naf 1
Hale, β-naf1 Hale, catechol, resorcinol,
Hydroquinone, 4-tert-ophthylcatechol, 4.4'-5ec-butylidenephenol, 2
．． 2'-dihydroxydiphenyl, 2゜2'-methylenebis(4-methyl-6-1, ertbutylphenol)
, 2.2'-bis(4-hydroxyphenyl)propane (also known as bisphenol A), 4.4'-isopropylidene-bis(2-tert-butylphenol), pyrogallol, phloroglucin, phloroglucincarboxylic 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-
G-ter 1:-Butylylyldiyl, 1-oxy-2-nattoic acid, gallic acid ester, salicylic acid ester, p-hydroxybenzoic acid ester, 4-hydroxyphthalic acid ester, 2-(4-human[1xyphenyl) -2-(3'-hydroxyphenyl)propane, 4
．． Examples include 4'-dihydroxy-3,3'diisopropyldiphenyl-2,2'-propane.

The binder used in the present invention is mainly composed of a water-soluble binder, and the coloring agent dispersed in fine particles is mixed with each other.
Examples include polyvinyl alcohol cymedyl cellulose, hydroxyethyl xerulose, polyacrylic acid, casein, gelatin, starch, and derivatives thereof.

The heat-sensitive recording layer of the present invention may contain additives as required, such as inorganic or organic pigments such as clay, calcium carbonate, synthetic silica, aluminum hydroxide, talc, titanium oxide, and zinc oxide, waxes, and anti-sudic substances. Various fatty acid metal salts for water resistance, water resistance agents, phenol resins, surfactants, etc. may be added for water resistance.

The paint for the heat-sensitive recording layer of the present invention is prepared by separately separating the leuco compound and organic acid, and then adding deoxyanisoin and, if necessary, additives such as pigments and sensitivity regulators to polyvinyl alcohol at an appropriate concentration. It is generally prepared by pulverizing and dispersing in an aqueous medium containing a binder, using a pulverizer such as a ball mill or a sand grinder, and then mixing and stirring a dye dispersion and an organic acid dispersion. It is advantageous in terms of color development efficiency to make each constituent material as fine as possible, and 05
It is preferable to atomize the particles to a particle size of ~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.

Coating can be performed using a conventional blade coater, air knife coater, bar coater, reverse roll coater, or the like.

As the support used in the present invention, paper such as high-quality paper, medium-quality paper, and coated paper is generally used, but other supports such as glass [T-sheet, plastic sticker 1~, and paper for film laminate 1] are also used. Can be used as a body.

U example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 a) Production of heat-sensitive recording material Liquids A and B having the following compositions were prepared by separately dispersing them in a pane 1 to sheaker (manufactured by Toyo Seiki) for 10 hours.

Solution A: Leuco dye 3-dibutylamino-6 methyl-7-anilinofluorane
59deoxyanisoin
8g zinc stearate
5.

Polyvinyl alcohol 12% liquid
35q water
/I79B liquid: Bisphenol A
15g zinc stearate
3U polyvinyl anodol 12% liquid
359 water
47q Next, 100 g of solution A, 100 g of solution B, 50 g of 12% polyvinyl alcohol solution, 15 g of synthetic silica P-832 (manufactured by Mizusawa Chemical Co., Ltd.), and 60 g of water.
Add jJ, mix and stir, prepare to make a coating liquid, then apply this coating liquid to the surface of 50g/TIt high-quality paper using a Mayer bar so that the coating amount after drying is 8g/bottom. The coating was applied and dried to obtain heat-sensitive recording paper.

Example 2 The formulation of Solution A used in Example 1 was the same as Example 1 except that 3-(N-isoamyl-N-ethyl)amino-6-medy-7-anilinofluorane was used as the leuco dye. A thermosensitive recording paper was obtained in the same manner.

Comparative Example 1 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that deoxyanisoin was not added to the formulation of liquid A used in Example 1.

Comparative Example 2 Same as Example 1 except that stearic acid amide was used instead of deoxyanisoin in the formulation of liquid A used in Example 1.
A thermosensitive recording paper was obtained in the same manner as above.

Comparative Example 3 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that parabenzylbiphenyl was used instead of deoxyanisoin in the formulation of Liquid A used in Example 1.

Comparative Example 4 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that 2-benzyloxynaphthalene was used instead of deoxyanisoin in the formulation of Liquid A used in Example 1.

The heat-sensitive recording papers obtained in the above Examples and Comparative Examples were surface-treated with a test super calender so that the recording surface had a Beck smoothness of 500 seconds.

Regarding the thermal recording paper obtained by this surface treatment, commercially available 1
7) G 77 Kushimi device FACOHFAX 621
C (manufactured by Fujitsu Ltd.), recording power 0.90W/dat,
Energization time 0.45 m5ec, periodic 5m5eC/I
Printing was carried out under the conditions of I, and the image density and background density at the time of printing were measured using a Macbeth densitometer. The storage stability was determined by measuring the image density and background density after storing the film in a dry state for 24 hours in a constant temperature room maintained at 60°C. The results obtained for Examples and Comparative Examples are shown in the table.

table It is clear that

Claims (1)

[Claims] A heat-sensitive recording material comprising a heat-sensitive recording layer comprising a leuco compound, an organic acid that reacts with the leuco compound to develop a color, and a binder on a support, wherein deoxyanisoin is contained in the heat-sensitive recording layer. A heat-sensitive recording medium characterized by the following.