JPS5942995A - Heat sensitive recording element - Google Patents

Abstract

PURPOSE:To provide a heat sensitive recording element forming a protective layer to the color image part thereof simultaneously with recording and capable of obtained recording good in chemical resistance, sensitivity and printing quality, obtained by superposing a heat sensitive recording sheet and a thermal transfer material so as to contact the heat sensitive color forming layer of the former and the heat meltable layer of the latter. CONSTITUTION:Heat sensitive recording paper 6 formed by providing a heat sensitive color forming layer 3 on a support (e.g., high grade paper) 4 and a thermal transfer material 5 formed by providing a colorless heat meltable layer (e.g., a layer comprising a hot melt composition constituted from waxes and resins and having a thickness of pref. 1-5mum) 2 on a thin base material (e.g., a polyimide resin film with a thickness of 8-25mum) 1 are superposed so as to contact the heat sensitive color forming layer 3 and the heat meltable layer 2 to obtain an objective heat sensitive recording element 7. EFFECT:The heat meltable layer is transferred onto a color image part 11 by performing printing under heating from the side of the base material 1 to enable the formation of a protective layer 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a storage layer in the colored image area at the same time as recording, so that the colored image area has chemical resistance and eliminates the harmful effects of scum and sticking during recording. 〇In recent years, thermal recording methods are non-impact,
It has many characteristics such as no noise during recording, no need for developing and fixing, and easy maintenance and management of equipment, so it is used in various fields including various printers and telephone facsimile machines. The thermal recording paper used is coated with a dye precursor such as crystal violet lactone and an acidic color developer such as a heptanoyl compound, and has the characteristics required for this type of thermal recording paper. Of course, it has a 7'C sensitivity suitable for various uses, the background is white, the colored image is stable for a long time and does not fade, there is no residue during recording, and there is a thermal head during recording. Although it is possible to manufacture products with excellent FC that meet many of these requirements, the storage stability (hereinafter referred to as "resistance") of the image area due to chemicals such as plasticizers, alcohol, acetone, benzene, xylene, etc. From a practical point of view, this is especially true when it comes into contact with erasers or polyvinyl chloride bags that contain large amounts of plasticizers, or when it comes into contact with hands covered with hand cream or hair styling oil. , the disadvantage is that the image becomes discolored and the characters become difficult to read.This phenomenon is caused by the lactone ring of the color-forming lactone compound, which is ring-opened with an acidic color developer, when the lactone ring of the chromogenic lactone compound, such as octyl phthalate such as dibutyl 7-thalerate, is removed. This is because ring closure occurs in the presence of a plasticizer, and it has been proposed that such development can be prevented by forming a film on the thermosensitive recording paper to prevent the penetration of the plasticizer.

(%Kokai No. 54-128347, JP-A No. 54-3549
However, the current situation is that there are many unsatisfactory points, such as a large decrease in sensitivity, the occurrence of sticking, and rapid printing performance. As a result of extensive research into a thermal recording material that has good print quality with little decrease in sensitivity and no scum or sticking, the present invention was arrived at. That is, a heat-sensitive recording paper having a heat-sensitive coloring layer provided on a support and a heat transfer material having a colorless heat-fusible layer provided on a thin base material are stacked with the heat-sensitive coloring layer and the heat-fusible layer in contact with each other. By performing thermal printing from the thin base material side of the combined new heat-sensitive recording material, the heat-fusible layer is transferred onto the colored image area of the heat-sensitive layer,
A protective layer is provided on the colored image area at the same time as recording.

In this new thermal recording material, the heating head comes into contact with the thin base material, so no scum or stickiness occurs.

The present invention will be explained below with reference to the drawings. FIG. 1 is a sectional view showing the thermal recording medium of the present invention.

1 is a thin base 4-112 is a colorless thermofusible layer, 3 is a thermosensitive coloring layer, 4 is a base paper, 5 is a thermal transfer material, 6 is a thermal recording paper, and 7 is a thermal recording medium of the present invention.

FIG. 2 shows the thermal head 8 performing thermal printing.

9 is a platen roll.

Figure 3 shows that the thermal transfer material was removed and a protective layer was provided only in the colored image area.

10 is a protective layer to which the heated portion of the colorless heat-fusible layer has been transferred; 1
1 is color development-@ part.

Since the protective layer No. 10 spreads laterally, it has a slightly wider area than one quadrant of the coloring tube No. 11.

If a heat-fusible ink layer is used as a substitute for the colorless heat-fusible layer 2 in Figure 1, and plain paper is used as a substitute for the heat-sensitive recording paper 6, a thermal transfer recording material is obtained. Its advantages over recording materials include good resolution, easy gradation recording, and no ink, so it does not stain hands, clothes, or equipment.

First, the thermal transfer material 5, which is a component of the thermal recording medium 7 of the present invention, will be explained, and then the thermal recording paper 6 will be explained.

The thermal transfer material 5 consists of a thin base material 1 and a colorless heat-fusible layer 2.

The thin base material 1 preferably has a thickness of 8 to 25 .mu.m from the viewpoint of transfer sensitivity of the heat-fusible layer.

The material should be selected from those with excellent heat resistance and strength. Resin films such as polyimide, polycarbonate, Teflon, and polyester, and thin paper such as capacitor paper are preferably used.

As the heat-melting layer 2, a colorless hot-melt composition composed of waxes and resins is suitably used. Examples of waxes include paraffin wax, microcrystal wax, mitsuro 9, spermaceti wax, and shellac. Wax, carnauba wax, candelilla wax, montan wax, low molecular weight polyethylene wax, etc. can be used.

Examples of resins that can be used include ethylene/vinyl acetate copolymers, ethylene/acrylate copolymers, rosin and rosin derivatives, petroleum resins, and the like.

Furthermore, light resistance can be imparted by adding an ultraviolet absorbent to the wax. The composition of the hot melt composition is as follows.

Composition Example of Hot Melt When the thickness of the hot melt layer is about 1 to 5/l, a good protective layer can be obtained after printing is transferred.

The thermosensitive recording paper 6 consists of a base paper 4 and a thermosensitive coloring layer 5. The base paper 4 is made of ordinary high quality paper.

The heat-sensitive color forming layer 3 can be one generally used for heat-sensitive paper, and will be explained in more detail as follows.

(A) Dye precursor crystal violet lactone, malachite green lactone, 8-diethylamino-7-methylfluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-diethylamine-7-sibenzylaminofluoran, 3-diethylamine-7-anilinofluorane, 3-(N-methylanilino)-7-7nylinofluorane, 3-diethylamino-7-(m-)lifluoromethylanilino)fluorane, 3-diethylamino-6-methyl- 7-7nilinofluorane, -a (N Z thylcyclohexylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-piveridino-6-methyl-7 -anilinofluorane, 3-(N-methyl-P-toluidino)-6-methyl-7-anilinofluorane, benzo-I
- Naphthospiropyran, etc.

@ Color developer phenol, para-tθrt-butylphenol, paraphenylphenol, α-naphthol, β-naphthol, 4.4'-isopropylidenediphenol, 4.4'
-5ea-butylidene diphenol, 4,4'-isopropylidene bis-(2-tθrt-butylphenol)
, 4,4°-cyclohexylidene diphenol, phenyl-4-hydroxybenzoate, novolac type phenolic resin, salicylic acid, 3-phenylsalicylic acid, 5-
Methyl salicylic acid, 3,5-di-tert-butyl salicylic acid, etc.

(c) Sensitizers stearamide, balmitic acid amide, oleic acid amide, lauric acid amide, ethylene bis stearamide, methylene bis stearamide, methylol stearamide, etc.

(D) Other polyvinyl alcohol, starch, sodium salt or ammonium salt of styrene-maleic anhydride copolymer,
Adhesives such as styrene-butadiene copolymer emulsion. Depending on the material, titanium dioxide, calcium carbonate,
Pigments such as kaolin, calcined kaolin, and aluminum hydroxide may also be added.

(4), (B), (C), and (D) are made into an aqueous dispersion and applied using a coater, and the coated surface is smoothed using a supercalender to obtain a heat-sensitive coloring layer.

The heat-sensitive coloring layer differs depending on the dye concentration, but usually 5 to 10
A clear marking can be obtained at the p position.

Next, the present invention will be specifically explained using examples.

Example (2) Preparation of heat-sensitive recording sheet Liquid A and B Liquids A and B were ground and dispersed in separate ball mills for 24 hours to prepare a coating liquid with the following formulation.

The @ solution prepared as above was applied to base paper with a basis weight of 50g/ze so that the coating k after drying would be 5.011/wl, and 6
After drying at 0° C. for 1 minute, the paper was heated using a super calendar to maintain a turbidity of 200 seconds or more to produce blue-colored thermal paper.

■ Preparation of thermal transfer material A hot melt layer was formed by coating a hot melt composition with the following composition on a capacitor paper with a thickness of 10 t+ and a density of 1.26 using a hot melt coater at a ratio of 3.011/d. A thermal transfer material was obtained.

■ Preparation of the heat-sensitive recording material of the present invention The heat-sensitive recording sheet obtained in step (2) and the heat transfer material obtained in (2) were superimposed so that the heat-sensitive coloring layer and the heat-melting layer were in contact with each other to obtain the heat-sensitive recording material of the present invention. .

When the heat-sensitive recording material of the present invention obtained in the example was printed by facsimile, there was no residue or sticking, and a clear image was obtained.Additionally, a drop of water was applied to the colored image area using a dropper.
When ~2 drops were added, no bleeding or fading occurred at all.

Furthermore, when 10 sheets of commercially available soft vinyl chloride film (Shin-Etsu Wrap) were stacked on the colored image area, a load of 601 /cd was applied, and the film was left for 24 hours, no fading occurred at all.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing the thermal recording material of the present invention. 0 1 is a thin base material, 2 is a colorless heat-fusible layer, 3 is a thermosensitive coloring layer, 4 is a base paper, 5 is a thermal transfer material, 6 is a Thermosensitive recording paper 7 is a thermosensitive recording medium of the present invention. FIG. 2 shows the thermal head 8 performing thermal printing. 9 is a platen roll. Figure 3 shows that the thermal transfer material has been removed and a protective layer has been applied only to the colored image area. 10 is a retention layer to which the heated portion of the colorless heat-fusible layer has been transferred; I
J is the number of color strokes.

Claims (1)

[Claims] A heat-sensitive recording sheet having a heat-sensitive color-forming layer whose main components are a dye precursor and a color developer that develops color from the dye precursor when heated on a support, and a colorless heat-melting layer on a thin base material. A heat-sensitive recording material in which a provided heat-transfer material is laminated with the heat-sensitive color forming layer and the heat-melting layer in contact with each other.