JPH0479313B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer recording medium. Specifically, the present invention relates to a thermal transfer recording medium that provides a good dye transfer image even on plain paper with low surface smoothness.

[Prior Art] A thermal transfer recording medium has been conventionally used as a recording medium for transferring and forming an image on a recording sheet such as plain paper by a thermal printer, a thermal facsimile, or the like. This thermal transfer recording medium has at least one coloring material layer on a support, and the coloring material layer includes, for example, a layer containing a coloring agent made of a dye such as a pigment and a heat-fusible substance. etc. are known. In addition, films with excellent surface smoothness and dimensional stability are used as the support in order to obtain good reproducibility of the dye transfer image obtained from the color material layer coated on the support. There is.

When these conventional thermal transfer recording media print on various types of paper ranging from paper with low smoothness to paper with high smoothness, they can print well on paper with high smoothness, but they print on paper with low smoothness. ``Fading'' occurs in the line drawing area, and in the case of so-called solid black, ``white spots'' occur.
appears and becomes very difficult to see. This is a major obstacle to the widespread use of thermal printers, and a solution is urgently needed.

On the other hand, thermal transfer recording media in which a resin layer is interposed between the support and the coloring material layer are also known from JP-A-57-36698, etc.; is mainly intended for printing two or more times, and when printed on plain paper with low smoothness, ``fading'' and ``white spots'' occur as described above.

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and it is possible to perform good printing in a wide smoothness range from paper with high smoothness to paper with low smoothness. The technical challenge is to

[Means for Solving the Problems] A thermal transfer recording medium of the present invention for solving the above-mentioned technical problem is a thermal transfer recording medium in which a heat-melting coloring material layer is laminated on a support. It is characterized in that a layer containing a naphthoquinonediazide derivative as a thermally expandable substance is interposed between the heat-melting coloring material layer.

The present invention will be described in further detail below.

The thermally expandable substance-containing layer in the thermal transfer recording medium of the present invention contains a thermally expandable substance and a resin as main components.

The thermally expandable substance used in the present invention expands when heated during recording, and acts to press the colorant components of the colorant layer to the transfer paper, and naphthoquinone diazide derivatives are used. .

In addition, when using a foaming agent with high photosensitivity such as naphthoquinone diazide derivatives, a light blocking substance,
For example, carbon black, ultraviolet absorbers, etc. are preferably added as additives to the thermally expandable material-containing layer.

The thermally expandable substance of the present invention is added in an amount of 0.1 to 90 parts by weight, preferably 1.0 to 60 parts by weight, more preferably 5.0 to 50 parts by weight, based on 100 parts by weight of the resin of the thermally expandable substance-containing layer. good.

The resin used in the thermal transfer recording medium of the present invention, which is kneaded with the thermally expandable substance to form the thermally expandable substance-containing layer, may be any resin as long as it has adhesion to the support and the coloring material layer. However, polyvinyl butyral resin, ethylene-ethyl acrylate resin, ethylene-vinyl acetate resin, epoxy resin, etc. generally give good results.

The thermally expandable material of the present invention may be incorporated into the thermally expandable material-containing layer using any method, such as dispersing it in a resin or dissolving it in a suitable solvent to add an additive to the thermally expandable material-containing layer. You can add it as

The present invention will be described in further detail below.

The heat-melting coloring material layer in the present invention may be any layer that can be partially or completely transferred to the transfer paper by heat, and may include a heat-melting substance (a low melting point substance or a low softening point substance), a coloring agent, etc. , whose main ingredient is a softener.

The heat-melting substance used in the present invention is a solid or semi-solid substance with a melting point (measured value by Yanagimoto MPJ-2 model) or a softening point (measured value by ring and ball method) of 40 to 120°C, more preferably 60 to 120°C. It is a solid substance,
Specific examples include plant waxes such as carnauba wax, wood wax, auricilla wax, and esparto wax, animal waxes such as beeswax, insect wax, serrata wax, spermaceti wax, paraffin wax, microcrystalline wax, and esters. In addition to waxes such as petroleum waxes such as wax and oxidized wax, mineral waxes such as montan wax, ozokerite, and ceresin; higher fatty acids such as palmitic acid, stearic acid, margaric acid, and behenic acid; palmityl alcohol, stearyl alcohol, Higher alcohols such as behenyl alcohol, marganyl alcohol, myricyl alcohol, eicosanol; higher fatty acid esters such as cetyl palmitate, myricyl palmitate, cetyl stearate, myricyl stearate; acetamide, propionic acid amide, palmitic acid amide, stearic acid amide ,
Amides such as amide wax; rosin derivatives such as ester gum, rosin maleic acid resin, rosin phenolic resin, and hydrogenated rosin; polymeric compounds such as phenol resin, terpene resin, cyclopentadiene resin, aromatic resin; stearylamine, behenyl Higher amines such as amines and palmitic amines; polyethylene oxides such as polyethylene glycol 4000 and polyethylene glycol 6000; these may be used alone, or
Two or more types may be used in combination. Among these, higher amides such as palmitic acid amide, stearic acid amide, oleic acid amide, and amide wax are particularly preferred. Also, the "thermofusible solid component that is solid at room temperature" described in JP-A-54-68253,
The "vehicle" described in JP-A-55-105579 may also be used.

The low melting point substance used in the coloring material layer of the present invention is particularly preferably a combination of a hard wax and a soft wax (one type or two or more types of each). Hard wax [25℃
(100g) (according to JIS K 2530)
Examples of waxes with a wax content of less than 8 include ester waxes (natural ester waxes such as carnauba wax and Montan wax, and waxes manufactured by Hoechst).
Hoechst Wax E, F, KP, KPS, BJ, OP,
synthetic ester waxes such as OM, X22, U and O), oxidized waxes (paraffin waxes,
Wax obtained by oxidizing wax such as microcrystalline wax, NPS manufactured by Nippon Seiro Co., Ltd.
-9210, NPS-6115, manufactured by Toyo Petrolite Co., Ltd.
PETRONABA・C, CARDIS 314, etc.), low molecular weight polyethylene wax (especially molecular weight 300~
1000, manufactured by Toyo Petrolite Co., Ltd.
POLYWAX 500 and 655, etc.), acid waxes (Hoechst Wax S and LP, etc. manufactured by Hoechst), and the like. Also, soft wax [25
Examples of waxes with a penetration degree (according to JIS K 2530) of 8 or higher at °C (100 g) include microcrystalline waxes (Nisseki Microwaxes 155 and 180 (manufactured by Nippon Oil Corporation), HI-MIC −1080,
HI−MIC−2065, HI−MIC−2095, HI−MIC−
1070, HI-MIC-1045, HI-MIC-2045 (manufactured by Nippon Seirosha), STAR WAX 100, BE SQUARE
175, 185, VICTORY, ULTRAFLEX (manufactured by Toyo Petrolite, etc.), stearic acid, behenic acid,
Stearyl alcohol, white wax, beeswax, dodecyl stearate, stearon, sorbitan monostearate, polyoxyethylene monostearate, or Diacarna 30 or Tirecarna.
Examples include PA30L (manufactured by Mitsubishi Kasei Corporation). In addition, when such hard wax and soft wax are used in combination, the weight ratio used is 1:9 to 9:1 (more preferably 2:8 to 9:1).
8:2) is fine.

The coloring agent to be contained in the color material layer of the present invention may be appropriately selected from dyes and pigments. Examples of the dye include direct dyes, acid dyes, basic dyes, disperse dyes, and oil-soluble dyes (oil-soluble metal complex salts). (including dyes), etc. These dyes may also be ballasted dyes. On the other hand, as the pigment, in addition to organic pigments such as phthalocyanine pigments, inorganic pigments such as carbon black can be used.

The coloring agent to be contained in the coloring material layer of the present invention is particularly preferably non-sublimable, and as a non-sublimating colorant, it can be transferred to a recording sheet such as plain paper together with a heat-fusible substance during heating recording. is possible,
Any non-sublimable substance that has a color may be used. Non-sublimable colorants preferably used in the present invention are colorants excluding sublimable (including those that vaporize with melting or dissolution) used in mordant dyes and the like.

Basic dyes preferably used as the colorant in the present invention include, for example, crystal violet (C.
Triphenylmethane dyes such as Malachite Green (CI42555), Malachite Green (CI42000), Methyl Violet (CI42535), Victoria Blue (CI44045), and Mazienta (CI42510), Auramine (C.
Diphenylmethane dyes such as I.655), Astraphloxin FF (CI48070), Eisenkathylon Yellow 3GLH (Hodogaya Chemical Co., Ltd. product, C.I.655), etc.
I.48055), Eisenkachironretsudo 6BH (C.
I.48020) Astrazone Golden Yellow GL
(Bayer product, CI48054), methine and azamethine dyes, rhodamine B (CI45170),
Xanthene dyes such as Rhodamine 6G (CI45160), thiazole azo and triazole azo dyes such as Astrazone Blue GL (CI11052), Astrazon Red F3BL (CI11055), Eisencathilone Blue 5GH (CI11085), methylene blue ( Quinoneimine dyes such as CI52015), insulating azo dyes with an onium group at the structural end such as Eisenkathyron Red GTLH (CI11085), Ceblon Yellow 3RL (DuPont product, CI11087), Astrazone Blue FGL (CI61512), etc. Examples include anthraquinone dyes.

Examples of oil-soluble metal complex dyes include symmetrical 1:2 type azo metal complex dyes, asymmetrical 1:2 type azo metal complex dyes, 1:1 type azo metal complex dyes, azomethine metal complex dyes, and formazan type metal complex dyes. Examples include metal complex dyes, metal phthalocyanine dyes, and organic base salts of these dyes. Specifically, Eisenspiron Yellow 3RH (Hodogaya Chemical Co. product, CI Solvent Yellow 25), Zapon Fast Yellow R (BASF product, CI18690), Eisenspiron Orange 2RH (CI Solvent Orange 40), Zapon Fast Scarlet B (C.
I.12783), Eisenspiron Red GEH (CI Solvent Red 84), Zaponphastrone BE
(CI12715), Zapon Fast Violet BE (C.
I.12196), Cyanine Blue BB (Sumitomo Chemical Co., Ltd. product,
CI74160), Variable Asto Black #3804 (Orient Chemical Company product, CI12195), Eisenspiron Yellow 3RH Special (CI Solvent Yellow 25:1), Eisenspiron Orange 2RH Special (CI Solvent Orange 40:1), Eisenspiron Blue 2BNH (CI Solvent Blue 117), Zapon Fuasto Blue HFL (C.
I.74350), Eisenspiron Black BH Special (CI Solvent Black 22:1), etc.

Acidic dyes such as CI Acid Yellow
19, CI Assisted Red 37, CI Assisted Blue
62, CI Acid Orange 10, CI Acid Blue 83, CI Acid Black 01, etc.

Direct dyes are CI Direct Yellow 44, CI
Direct Yellow 142, CI Direct Yellow 12, CI Direct Blue 15, CI Direct Blue 25, CI Direct Blue 249, CI Direct Red 81, CI Direct Red 9, CI Direct Red 31, CI Direct Black 154,
Examples include CI Direct Black 17.

The disperse dyes are CI Dispose Yellow 5, C.
I. Dispose Yellow 51, CI Dispose Yellow 64, CI Dispose Red 43, CI Dispose Red 54, CI Dispose Red 135,
Examples include CI Dayspose Blue 56, CI Dayspose Blue 73, and CI Dayspose 91.

The ballasted dyes used in the present invention are dyes having at least one ballast group in the dye matrix, such as azo dyes, azomethine dyes, anthraquinone dyes, naphthoquinone dyes, stearin dyes, quinophthalo dyes, and phthalocyanine dyes. Ballast groups are groups that are highly soluble in heat-melting substances, such as alkyl groups, cycloalkyl groups, aralkyl groups, alkoxy groups, alkylsulfonylamino groups, alkylsulfonyl groups, hydroxylalkyl groups, cyanoalkyl groups, alkoxycarbonylalkyl groups,
It is a group having an alkyl group having 6 or more carbon atoms, such as an alkoxyalkyl group and an alkylthio group, or an alkylene group. In particular, a ballast group having at least one alkyl group having 6 or more carbon atoms in the molecule is preferred. As an example of the structure of the ballasted dye preferably used in the present invention,
Examples include those described in patent application (A) filed on the 25th, but the present invention is not limited thereto.

The softener used in the present invention includes a low softening point resin selected from ethylene-ethyl acrylate resin, ethylene-vinyl acetate resin, etc., preferably one with a softening point (value measured by ring and ball method) of 40 to 90°C. .

Although the composition ratio of the coloring material layer of the present invention is not limited,
Total solid content of coloring material layer: 100 parts (parts by weight, same below)
50 to 95 parts (more preferably 70 to 95 parts) of the heat-melting substance, 5 to 20 parts of the colorant, and 0 to 20 parts of the softener.
30 parts (more preferably 1 to 10 parts).

The color material layer of the present invention may contain various additives in addition to the above components. For example, castor oil,
Vegetable oils such as linseed oil, olive oil, animal oils such as whale oil and mineral oils may be suitably used.

Note that the support used in the thermal transfer recording medium of the present invention preferably has heat-resistant strength, high dimensional stability, and high surface smoothness. Materials include, for example, papers such as plain paper, condenser paper, laminated paper, coated paper, resin films such as polyethylene, polyethylene terephthalate, polystyrene, polypropylene, polyimide, paper-resin film composites, aluminum foil, etc. Metal sheets and the like are preferably used. The thickness of the support is usually approximately
It is preferably 60 μm or less, particularly 2 to 20 μm.
Furthermore, in the thermal transfer recording medium of the present invention, the structure on the back side of the support may be optional, and a backing layer such as a sticking prevention layer may be provided.

In the thermal transfer recording medium of the present invention, a technique suitable for applying the thermally expandable material-containing layer to a support such as a polymer film and a heat-melting coloring material layer applied on the thermally expandable material-containing layer are used. The technology suitable for
These techniques are known in the art and are described in the above-mentioned Japanese Patent Laid-Open Nos. 54-68253 and 55-105579, and these techniques can also be used in the present invention. For example, the thermally expandable substance-containing layer (and the thermally meltable coloring material layer) can be formed by hot melt coating with the composition, or by solvent coating with a coating solution obtained by dissolving or decomposing the composition in an appropriate solvent. This is the layer that was formed. As a coating method for the thermally expandable substance-containing layer (and thermally meltable colorant layer) of the present invention, any known technique can be employed, such as a reverse roll coater method, an extrusion coater method, a gravure coater method, and a wire bar coating method. . The heat-melting coloring material layer of the present invention has a thickness of 20 μm or less, more preferably 1 μm or less.
The thickness may be 15 μm. Further, the thermally expandable substance-containing layer of the present invention preferably has a thickness of 5 μm or less, more preferably 0.1 to 3 μm or less.

The thermal transfer recording medium of the present invention may contain highly thermally conductive fine powder in its constituent layers or in its support. The high thermal conductivity fine powder has a higher thermal conductivity than the above-mentioned resin (for example, thermal conductivity of 6.0×
10 ^-4 × 25.0 × 10 ^-4 cal/ses・cm・℃) and has a high melting point. Many metals such as aluminum and copper are possible, and tin oxide, aluminum oxide, magnesium oxide, etc. Oxides of titanium and nitrides such as titanium nitride can also be used. The particle size of the highly thermally conductive fine powder is preferably 3 μm or less, more preferably 0.01 to 1 μm. For example, when the resin is contained in the thermally expandable material-containing layer, the mixing ratio of the resin and the fine powder is preferably such that the volume fraction of the fine powder is 10 to 90%, more preferably 20 to 60%.

The highly thermally conductive fine powder is preferably contained dispersedly in the thermally expandable substance-containing layer, but it may also be contained in the support and/or the coloring material layer.

The heat-sensitive transfer recording medium of the present invention may have other constituent layers such as an undercoat layer (for example, a layer for improving film adhesion) and an overcoat layer (for example, a layer made of a heat-melting substance). good.

[Function] The thermal transfer recording medium of the present invention can be recorded (printed) on a recording sheet such as plain paper by the same method as known thermal transfer recording media. For example, the coloring material layer is dissolved when heated with a thermal head. At the same time, the thermally expandable substance thermally expands, and the melted coloring material layer is effectively transferred to the recording sheet, which is a transfer medium with low smoothness, due to this pressure. In addition, when the thermally expandable material foams, the voids created by the foaming increase the releasability, making it possible to perform good printing even on paper with low smoothness.

[Effects of the Invention] According to the present invention, in a heat-sensitive transfer recording medium in which a heat-melting coloring material layer is laminated on a support, a heat-expandable substance-containing layer is provided between the support and the heat-melting coloring material layer. Because of the structure in which the above-described technical problem of the present invention is solved by the simple means of using a thermally expandable material, the above-mentioned technical problem of the present invention can be solved.

Example 1 A thermally expandable material-containing layer coating solution having the following composition was applied onto a 5.3 μm thick polyethylene terephthalate film using a wire bar.

Coating liquid for layer containing thermally expandable substance Polyvinyl butyral resin (BL-1 manufactured by Sekisui Chemical Co., Ltd.) 3 parts 2,3,4-trihydroxybenzophenone
1,2-naphthoquinone diazide-4-sulfonic acid monoester 2.5 parts Carbon black 3 parts Methyl ethyl ketone 100 parts The thickness of the layer containing the thermally expandable substance after drying is approximately 1 μm.
It was hot. Next, the following coloring material layer coating liquid was applied onto the thermally expandable substance-containing layer using a wire bar, and dried at 40°C to obtain a thermal transfer recording medium sample of the present invention. The dry film thickness of the coloring material layer is approximately 4μm
It was hot.

Coloring layer coating liquid Carbon black 10 parts Carnauba wax 40 parts Ethylene-ethyl acrylate resin (NUC-
6070 manufactured by Nippon Unicar Co., Ltd.) 2 parts Toluene 120 parts Using this thermal transfer recording medium sample, one heating element was printed using a thermal printer (a prototype machine equipped with a thin-film line thermal head with a heating element density of 8 dots/mm). Recording was performed by applying energy with an applied power of 0.9 W and an application time of 2 milliseconds. Bond paper (Beck smoothness 12) is used as transfer paper.
seconds) was used.

As a result, clear printing was obtained with no "fading" in the line drawings and no "white spots" in the solid black areas.

Comparative Example 1 Similarly to Example 1, a resin layer without 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid monoester was formed on a 5.3 μm thick polyethylene terephthalate film. Coated. After drying, a color material layer having the same composition as in Example 1 was applied so that the dry film thickness was about 4 μm. After drying at 40°C, printing was carried out in the same manner as in Example 1, but "fading" occurred in the line drawing areas, and "white spots" appeared in the solid black areas, resulting in printing that was very difficult to see.

Claims (1)

[Claims] 1. In a heat-sensitive transfer recording medium in which a heat-melting coloring material layer is laminated on a support, a layer containing a naphthoquinone diazide derivative as a thermally expandable substance is interposed between the support and the heat-melting coloring material layer. A thermal transfer recording medium characterized by: