JPS6253882A - Thermal transfer recording medium - 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 Technical Field The present invention relates to a thermal transfer recording medium on which a recorded image is transferred by heating with a thermal heater, laser, or the like.

Conventional heat-sensitive transfer recording media include transfer sheets with a heat-sublimable dye layer on a support, and transfer sheets with a heat-fusible substance and pigment on a support. , is used to form an image on a receiving sheet by thermal printing.

However, although methods using heat-sublimable dyes have excellent gradation expression in a single image, they have the drawbacks of low heat sensitivity and poor image storage stability, and also use heat-fusible substances and pigments. This method has excellent thermal sensitivity and storage stability, but has the drawback of not being able to express gradation.

1-Ichie The present invention aims to improve the drawbacks of the above-mentioned prior art,
It is an object of the present invention to provide a thermal transfer recording medium capable of producing high S degree images having excellent thermal sensitivity and particularly excellent gradation.

1-1 The present invention contains a heat-melt ink component whose main components are a heat-melt substance that is solid at room temperature, a colorant, and a gradation control agent in a microporous structure made of a resin formed on a support. A thermal transfer recording medium having a structure in which the gradation control agent contains an azo compound having the following chemical structural formula.

X+N=N-Y)n However, The colorant in the ink is tightly held.

This coloring agent is melted by heating with a thermal head, etc., and oozes out from between the network structures of the gradation control agent having the above chemical structure, and then oozes out from the microporous structure of the resin and is deposited on the receiving sheet. It oozes out little by little. The amount of colorant that oozes out varies depending on the amount of thermal energy applied by a thermal head, etc. By controlling the applied thermal energy, it is possible to change the amount of colorant transferred, and the gradation can be faithfully reproduced. It is possible to obtain an image that is clearly and broadly represented.

Although the reason is not clear, the substance with the chemical structure used in the present invention has better wettability and compatibility with resin than low-melting substances such as oil and wax, which are the main components of molten ink, and has a sponge resin structure. It is firmly held within the membrane, and its presence delicately controls the pore size of the porous tissue to become smaller. Therefore, even when thermal energy is applied, it is not transferred out, but is retained in the porous structure, and acts as a good gradation control agent by controlling the amount of colorant and ink existing in the surrounding area that transfers. it is conceivable that.

Here, the level of heating energy varies depending on the type of each material and the thickness of the ink JII, and is a relative value.

As the support used in the present invention, conventionally known films and papers can be used as they are, such as films of relatively heat-resistant plastics such as polyester, polyamide, polycarbonate, triacetylcellulose nylon, and polyimide. , cellophane, condenser paper, parchment paper, etc. can be suitably used. The thickness of the support is preferably about 2 to 15 microns when considering a thermal head as a heat source for thermal transfer, but it is preferable to use a heat source that can selectively heat the thermal transfer ink layer, such as a laser beam. There are no particular restrictions in this case. In addition, when using a thermal head, the surface of the support that comes into contact with the thermal head may be made of silicone resin, fluororesin, polyimide resin,
The heat resistance of the support can be improved by providing a heat-resistant protective layer made of epoxy resin, phenol resin, melamine resin, nitrocellulose, etc., or it is also possible to use support materials that could not be used conventionally. .

Although the %31 method for forming a heat-melting ink layer having the above-described structure is not particularly limited, the following method is generally used. That is, a gradation control agent and a coloring agent,
The ink dispersion (or a solution) is obtained by mixing and dispersing the holding material and a suitable organic solvent using a dispersion device such as an attritor or a ball mill. Separately, a solution of the resin dissolved in an organic solvent is obtained, mixed with the ink dispersion, and uniformly dispersed using a mixer such as a ball mill.

Next, the resulting dispersion is applied onto a support and dried to obtain a hot-melt ink layer having the above-mentioned fine structure. A wetting agent, a dispersant, etc. may be added to the dispersion liquid in order to improve the dispersion of the above-mentioned gradation control agent, colorant, and holding material. Further, if necessary, a filler commonly used in the resin coating of this scale can be added. The resin constituting the microporous resin structure is selected from vinyl chloride, vinyl acetate, vinylidene chloride, acrylic acid, methacrylic acid, acrylic ester, and methacrylic ester in relation to the oil-based carrier as described below. Thermoplastic resins such as monomers or copolymers, and phenol, furan, formaldehyde, urea, melamine,
It is preferable to use a thermosetting resin such as alkyd, unsaturated polynisder, or epoxy.

Alternatively, a substance that is incompatible with the resin forming the porous weave and soluble in a solvent that does not dissolve the resin is kneaded together with the resin, and the mixture is coated on the support to form a resin layer. A thermal transfer layer having the above-described structure can also be obtained by dissolving the substance in the above-mentioned solvent to form a porous resin structure, and then filling the porous structure with a thermal transferable ink.

Specific examples of tone adjusting agents having the above chemical structural formula are as follows:
tan3 The amount of this gradation control agent added is 0.1 to 10 parts by weight of the dye.
Parts by weight, preferably 0.3 to 5 parts by weight.

@Specific examples of coloring materials include the following.

Coloring dyes and color pigments may be used, but dyes can provide images with more preferable gradation.

Examples of such dyes include the following direct dyes, acid dyes, basic dyes, mordant dyes, sulfur dyes, vat dyes, azoic dyes, oil dyes, heat sublimable disperse dyes, and the like.

1) Direct dyes: Direct Sky Blue, Direct Black W, etc.

2) M dye: tartrazine, acid violet 6
B, Acid Fast Red 3G, etc.

3) Basic dyes: safranin, auramine, crystal violet, methylene blue, rhodamine B, Victoria blue B, etc.

4) Mordant dyes: Sunchromine Fast Blue-MB, Elio from Azurol B1 Alizarin Yellow B, etc.

5) Liillization dye: Sulfur Brilliant Green 4G, etc.

6) Vat dyes: indanthremble, etc.

7) Azoic dyes: naphthol As, etc.

8) Oil dye: Nigrosine, Spirit Black EB,
Varifast Orange 3206, Oil Black 215
, Butter Ye 0-, Sudan Blue ■, Oil Red B
10-Damin B et al.

9) Heat-sublimable disperse dye (9-1) Monoazo disperse dye: Disbird's First Yellow G1 Disbird's First Yellow 5G,
Disbirds First Yellow SR, Disbirds Red R, etc.

(9-2) Anthraquinone disperse dye: Disperse First Violet OR, Disperse First Violet B1 Disperse Blue Extra, Disperse First Brilliant Blue B, etc.

(9-3) Nitrodiphenylamine-based disperse dye: Tis Birds Fast Yellow RR1, Di's Birds Fast Yellow G1, etc.

It is sufficient that the particle size of these dyes is smaller than that of the tone control agent having a network structure, and it is preferable that these dyes are in a dissolved state.

As the holding material, any one of liquid, semi-solid, and heat-melting solid can be used as long as it is incompatible with the above-mentioned resin and is non-volatile. As liquid retaining materials, for example, animal and vegetable oils such as cottonseed oil, rapeseed oil, and whale oil; or mineral oils such as motor oil, spindle oil, and dynamo oil are used; as semisolid carriers, for example, lanolin, petrolatum, lard, etc. are used. Furthermore, as a solid holding material,
Heat-melt binders constituting heat-melt ink in ordinary heat-sensitive transfer materials can be used, such as carnauba wax, paraffin wax, Sasol wax,
Waxes such as microcrystalline wax and castor wax, nistearic acid, balmitic acid, lauric acid, aluminum stearate, lead stearate, barium stearate, zinc stearate, zinc palmitate,
Higher fatty acids such as methyl hydroxystearate 1, glycerol monohydroxystearate, or their metal salts, derivatives such as esters; polyethylene, polypropylene, polyisobutylene, polyethylene wax, polyethylene oxide, polytetrafluoroethylene, ethylene-acrylic acid Thermoplastic resins made of olefins alone or copolymers, such as copolymers, ethylene-ethyl acrylate copolymers, ethylene-vinyl acetate copolymers, or derivatives thereof, are used.

These holding materials may be used alone or in combination of two or more in an amount of 50 to 2 parts per 100 parts of the thermoplastic resin constituting the thermal transfer layer.
00 parts.

In addition, in order to more strongly maintain the network structure of the porous resin structure and the gradation control agent, it is also possible to provide an intermediate adhesive layer on the support in advance.

Examples of the intermediate adhesive layer include so-called Plusdec resins and plastic resins with fillers added thereto.

The receiving sheet may basically be plain paper or synthetic paper, but if necessary, it may be made of the above resins, TiOz, silica, ZnO
It is also possible to apply a filler containing fillers such as the like on plain paper to facilitate the transfer of the colorant.

Next, examples and comparative examples will be described. All parts indicate parts by weight.

Example 1 Sudan Red 460 (coloring dye) (manufactured by BASF) 10 parts 2.7-pis[2-hydroxy-3-(2-chlorophenylcarbamoyl) naphthalen-1-ylazo]-9-pulurenone<rII control agent ) 10 parts modified lanolin oil (retaining material) 30 parts carnauba wax (retaining material) 20 parts paraffin wax (retaining material) 20 parts powder 0.5 parts liquid paraffin 5 parts
The mixture was thoroughly dispersed in a ball mill for about 48 hours with a mixed solution of 100 parts of methyl ethyl ketone and 130 parts of toluene at .

Next, a 20% by weight chloride-vinyl-acetate-picopolymer resin solution (10 parts of resin, 20 parts of toluene, 20 parts of methyl ethyl ketone)
300 parts were added to the above ink dispersion and dispersed in a ball mill for about 1 hour to prepare a coating of a thermal transfer composition.

This coating was applied to the surface of a polyester film with a silicone resin heat-resistant layer on the back side with a thickness of 6 μm using a wire bar, dried at a drying temperature of 100°C for 1 minute, and heated to a thickness of about 5 μm. An ink layer was formed.

The ink layer of the transfer medium thus obtained was stacked so as to face the synthetic paper receiver, and an image was recorded using a thermal head from the back side of the transfer medium by varying the heating energy, as shown in the table below. Further, the N-opening control agent was not transferred to the receiving sheet at all, and a clear magenta image was recorded.

It can be seen that the image density changes gradually as the heating energy changes, and the gradation reproduction is further expanded. Further, the density of the recorded image hardly changed even after the recorded image was stored in a constant temperature bath at 60° C. for 50 hours.

Example 2 The floor m control agent of Example 1 was used as Vulcan FastYel.
low G, and the colored dye Sudan Blue 670 (
All procedures were carried out in the same manner except that the recording medium (manufactured by BASF) was replaced, and the image recording results were cyan-colored images as shown in the table below.

Example 3 The gradation control agent of Example 1 was used as permanent Carm.
Everything was carried out in the same manner except that the color dye was replaced with Sudan Yellow 150 (BASFM) and the coloring dye was replaced with Sudan Yellow 150 (BASFM). A clear yellow image was recorded without any transfer.

Example 4 Kayasera!・Black G (manufactured by Nippon Kayaku) (colorant)
8 parts 4,4''-bis[2-hydroxy-3-(2,4-
dimethylphenyl)carbamoylnaphthalen-1-ylazo)-1,4-distyrylbenzene (tone control agent) 1
5 parts Machine oil (retention agent) 20 parts Carnauba wax (retention agent) 20 parts Castor wax (retention agent) 20 parts Powder
0.4 part liquid paraffin
4 parts The above heat-melting ink valve was sufficiently dispersed in the same manner as in Example 1, and a resin solution of vinyl chloride-vinyl acetate copolymer was added and dispersed in the same manner to prepare a coating of a heat-sensitive transfer composition.

Next, a heat-melting ink layer having a thickness of about 4 μm was coated in the same manner as in Example 1.

Next, when image recording was performed in the same manner as in Example 1,
As shown in the table below, no gradation control agent was transferred to the receiving sheet, and a clear black image was recorded.

Even when the gradation control agent of Example 1 was replaced with the following, the gradation properties were similarly excellent, and a clear magenta image was recorded without transfer of the gradation control agent to the receiving sheet side.

Example 5 Hansa Y yellow 5G Example 6 Permancnt Red F R
extra Example 7 Vulcan Fast Bl
As a ue 3G comparative example, the gradation control agent in Example 1 was replaced with a pigment as described below.

Comparative Example 1 Quinacridone pigment HosapermPin
k E jrans (manufactured by Hoechst) Comparative Example 2 T
ripheny1methane pigment Reflex31
ue150 (manufactured by Hoechst) Comparative example 3 [)iazo pigment permanent
YellowGGO2 (manufactured by Hoechst) Comparative example 4 Carbon black P rintex 9
0 (manufactured by egussa) Comparative example 5 Carbon black Raven 410 (C
obmbia) Comparative Example 6 Graphite UFO-5 (Showa Denko) Comparative Example 7
ZnO5azex4000 (manufactured by Sakai Chemical Co., Ltd.) Image recording was performed in the same manner as in Example 1, and the results are shown in the table below.

Note: The gradation control agent was transferred to the receiving sheet side on each side.In all cases, the gradation characteristics were more steep and the gradation was worse than those of Examples 1 to 7. Worse still, the gradation of the comparative example was ll
The 111 agent is transferred to the receiving sheet side along with the heating energy, making it impossible to produce a clear color of the coloring agent.

Effects As is clear from the above explanation, the thermal transfer recording medium of the present invention allows ink to flow between the porous resin structure and the filler (acicular crystals) having a network structure, depending on the magnitude of heating energy. Nt oozes out and transfers to the receiving sheet surface, so by controlling the heating energy during transfer, Nt
Transfer images with excellent lJ expression and wide gradation reproduction can be obtained, the images have good storage stability, and full-color images can be obtained by selecting various dyes.

Claims (1)

[Claims] In a microporous structure made of resin formed on a support,
In a thermal transfer recording medium having a structure containing a heat-melting ink component whose main components are a heat-melting substance that is solid at room temperature, a colorant, and a tone control agent, the tone control agent has the following chemical structural formula. A thermal transfer recording medium comprising an azo compound. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, X: diazonium salt residue Y = coupler residue n: 1, 2, 3