JPH0533154B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a thermal transfer recording medium that can be used multiple times. More specifically, the present invention relates to a thermal transfer recording medium that enables multiple printing with high print density and good print quality even on transfer paper with low surface smoothness.

[Prior art] As thermal transfer recording media intended for multiple uses, Japanese Patent Application Laid-open Nos. 54-68253, 55-105579, and
No. 57-185191 discloses a resin matrix (microporous network structure) impregnated with heat-melting ink, and JP-A No. 57-160691 discloses a resin matrix (microporous network structure) impregnated with heat-melting ink, and JP-A No. 57-160691 discloses a resin matrix (microporous network structure) impregnated with hot-melt ink. Impregnated with hot melt ink is disclosed. However, since the resin and fine particles of these are non-transferable, the amount of transfer ink per unit volume is small, and therefore, in order to print multiple times, the film thickness must be increased. However, increasing the film thickness causes a fatal drawback of insufficient sensitivity. These methods also have the disadvantage that the edges of the printed image become unclear because the ink layer (color material layer) is too thick.

JP-A-57-36698 proposes a thermal transfer recording medium that solves these drawbacks by interposing a resin layer (adhesive layer) made of polyvinyl butyral between the ink layer (coloring material layer) and the support. A technique has been disclosed that enables printing multiple times using a thin ink layer (coloring material layer). This technology improves the adhesion between the ink layer (color material layer) and the support, and it is certainly possible to print with high density using relatively low energy. The drawback is that the density of the image is significantly reduced. In order to suppress such a decrease in density, increasing the amount of the heat-softening polymer substance added can suppress the decrease in the density of the dye transfer image that accompanies the number of uses, but the ink layer (coloring material layer) itself As the ink becomes stronger, less ink is transferred to the transfer paper, and as a result, it has the fatal drawback that only low-density prints can be obtained from the first print, and both seem to be of little practical use. It was a thermal transfer recording medium.

[Problems to be Solved by the Invention] Therefore, in order to provide a thermal transfer recording medium that does not have the above-mentioned drawbacks, the present inventor has conducted extensive research, and has found that in order to enable high-density printing multiple times, it is necessary to Cohesive failure may occur, where the ink layer (coloring material layer) does not peel off at the interface between the support and the adhesive layer or the adhesive layer and the ink layer (coloring material layer), but peels off inside the ink layer (coloring material layer). We found out that it was necessary, focused on this point, and applied for patent application No. 59-218279.
No. 59-235166 and No. 59-235167, we have previously proposed a technology that controls this cohesive failure and enables high-density printing multiple times.

However, as a result of further research, these previously proposed techniques were found to be very effective for so-called high-quality transfer paper (for example, transfer paper with a surface smoothness of 100 seconds or more in Beck's smoothness); It has been found that the use of rough paper (for example, transfer paper with a rough surface with a base smoothness of about 30 seconds) has a disadvantage in that the multi-printability is reduced.

Therefore, the technical object of the present invention is to provide a thermal transfer recording medium that enables multiple printing with high print density and good print quality even on transfer paper with low base smoothness.

[Means for Solving the Problems] As a result of intensive research, the present inventor has developed a heat-sensitive transfer recording medium that has a heat-melt coloring material layer on a support and can be used multiple times. The above technical problem is solved by the colorant layer containing at least one of polyglycerol fatty acid ester represented by the following general formula (1) or polyethylene glycol fatty acid ester represented by the following general formula (2). The present invention was based on this discovery.

General formula (1) In the above formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ each may be the same or different and represent a hydrogen atom or an acyl group having 6 to 30 carbon atoms, and n is an integer of 1 to 20.

General formula (2) In the above formula, R ₆ and R ₇ may be the same or different,
It represents an alkyl group, an alkenyl group, or an aralkyl group having 6 to 30 carbon atoms, and n is an integer of 1 to 20.

The present invention will be described in further detail below.

The heat-sensitive transfer recording medium of the present invention has at least one or two or more heat-melting coloring material layers on a support. Although this heat-melting coloring material layer may be directly coated on the support, it is preferably provided on the support via an adhesive layer.

In the present invention, the heat-melting coloring material layer includes a polyglycerol fatty acid ester represented by the following general formula (1) or a polyethylene glycol fatty acid ester represented by the following general formula (2) (hereinafter referred to as the substance of the present invention),
Contains heat-melting substances, colorants, heat-softening polymer compounds, etc.

The substance of the present invention has solubility in liquid paraffin, but is insoluble at temperatures below 40°C. Insolubility of the substance of the present invention at temperatures below 40°C means that it is insoluble in liquid paraffin at a concentration of 10%. is soluble in liquid paraffin means that the temperature exceeds 40℃,
It means dissolving in liquid paraffin at a concentration of 10%, preferably at a temperature of 60°C or higher. In addition, in the present invention, liquid paraffin is a relatively low-viscosity lubricating oil that has been highly purified by treatment with oleum.
It is a colorless, transparent, odorless, non-fluorescent oil with low viscosity, such as what is known as liquid paraffin reagent.

Next, a polyglycerin fatty acid ester represented by the following general formula (1) and a polyethylene glycol fatty acid ester represented by the following general formula (2) will be explained.

General formula (1) In the above formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ each may be the same or different and represent a hydrogen atom or an acyl group having 6 to 30 carbon atoms, and n is an integer of 1 to 20.

Among these acyl groups, those having a long chain hydrocarbon are particularly preferred. Examples include caproyl group, lauroyl group, myristoyl group, palmitoyl group, stearoyl group, behenoyl group, serotoyl group, montanoyl group, oleoyl group, linoleoyl group, and the like.

General formula (2) In the above formula, R ₆ and R ₇ may be the same or different,
It represents an alkyl group, an alkenyl group, or an aralkyl group having 6 to 30 carbon atoms, and n is an integer of 1 to 20.

The substance of the present invention can also be obtained as a commercial product. For example, in the case of the above-mentioned polyglycerin fatty acid esters, "Hexagrin 3S", "Hexagrin 5S", "Decagrin 3S", "Decagrin 5S", "Decagrin 7S", etc. manufactured by Nikko Chemical Co., Ltd. can be suitably used.

The substances of the present invention are not limited to those mentioned above, but can be used alone or in combination of two or more, including the commercially available substances mentioned above.

The method of incorporating the substance of the present invention into the heat-melting coloring material layer is arbitrary. For example, the substance of the present invention may be added or dispersed in the coating liquid for the heat-melting coloring material layer as it is, or after being dissolved in an appropriate solvent. After that, the coating liquid may be applied.

In the present invention, by incorporating the above-mentioned substance of the present invention into the heat-melting coloring material layer, it is possible to print multiple times with high print density and good print quality even on transfer paper with low base smoothness. . The reason why this effect can be exerted is not necessarily clear, but because the heat-melting substance that is one of the colorant layer compositions has a long-chain hydrocarbon in its structural formula, It is considered that the behavior of the substance of the present invention in the colorant layer composition is similar to that in the colorant layer composition. That is, the substance of the present invention and the hot-melting material, which were probably compatible when the components of the colorant layer composition were heated and mixed for coating on the support, were coated on or on the support. At the stage when it is applied and solidified on the adhesive layer, the substance of the present invention and the contained heat-fusible substance undergo microscopic phase separation, imparting cohesive failure properties to the colorant layer. This is thought to be due to this.

Examples of the heat-melting substance used in the present invention include substances that are capable of dissolving colorants during thermal transfer and are solid at room temperature, preferably substances having a melting point or melting point of 40 to 80°C. Further, the heat-melting substance of the present invention preferably has a long-chain hydrocarbon in its structural formula, and specific examples thereof include the following.

[Specific examples] Plant waxes such as auricilla wax, esparto wax, tree wax, beeswax, insect wax, animal waxes such as seracula wax, whale wax, paraffin wax,
In addition to waxes such as petroleum waxes such as microcrystalline waxes, ester waxes, and oxidized waxes, and mineral waxes such as montan wax, ozokerite, and ceresin, there are also high-grade waxes such as cetyl palmitate, myricyl palmitate, cetyl stearate, and myricyl stearate. Fatty acid ester, acetamide, propionic acid amide, palmitic acid amide,
Amides such as stearic acid amide and amide wax; natural oils and fats such as palm oil, pork oil, beef oil, and mutton tallow; oils and fats such as glycerin esters of long-chain fatty acids; palmityl alcohol, stearyl alcohol, behenyl alcohol, marganyl alcohol; Myricyl alcohol, eicosanol, palmitic acid, stearic acid, margaric acid, behenic acid, etc.

The heat-melting substances used in the present invention are not limited to the above-mentioned waxes, oils and fats, higher alcohols, and higher fatty acids, but any one or two of these (for example, a combination of waxes, (including combinations of waxes and higher alcohols) can be selected and used.

The coloring agent used in the color material layer of the present invention may be appropriately selected from various dyes and pigments. Examples of the dye include direct dyes, acid dyes, basic dyes, disperse dyes, oil-soluble dyes (oil-soluble metal (including complex salt dyes). 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 is necessary to add a heat-fusible substance to the transfer paper or sheet such as plain paper during heating recording. Any non-sublimable substance that can be transferred and 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
Methine and azamethine dyes such as (Bayer product, CI48054), 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 Co., Ltd. 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, sterine 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, hydroxyalkyl groups, cyanoalkyl groups, alkoxycarbonylalkyl groups, and alkoxy groups. It is a group having an alkyl group or an alkylene group having 6 or more carbon atoms, such as an alkyl group or an alkylthio group. In particular, a ballast group having at least one alkyl group having 6 or more carbon atoms in the molecule is preferred.
Examples of structures of ballasted dyes preferably used in the present invention include those described in Japanese Patent Application No. 81,688/1982, but the present invention is not limited thereto.

It is preferable that the coloring material layer of the present invention contains a heat-softening polymer compound. The heat-softening polymer compound used in the present invention preferably has a softening point (measured by the ring and ball method) of 40 to 200°C, and either natural or synthetic hydrophilic polymers or hydrophobic polymers can be used.

Examples of hydrophilic polymers include gelatin, gelatin derivatives, cellulose derivatives, proteins such as casein, natural products and natural product derivatives such as polysaccharides such as starch, water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone, and acrylamide polymers. Examples include synthetic water-soluble polymers such as polyvinyl compounds, and vinyl-based and polyurethane-based polymer latexes. Hydrophobic polymers include US Pat. No. 3,142,586;
No. 3143386, No. 3062674, No. 3220844, No.
Examples include the synthetic polymers described in No. 3287289 and No. 3411911. Preferred polymers include polyvinyl butyral, polyvinyl formal, polyethylene, polypropylene, polyamide, ethyl cellulose, cellulose derivatives such as cellulose acetate, polystyrene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, ethylene-ethyl acrylate, and ethylene-ethyl acrylate.
Vinyl acetate, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic acid terpolymers, acrylic resins such as polymethyl methacrylate, polyisobutylene, rosin derivatives such as ester gums, petroleum resins, coumaron indene resins, Examples include cyclic rubber and chlorinated rubber.

The present invention is not limited to the above heat-softening polymer compounds, but one type or a combination of two or more types thereof can be used.

Although it is not necessary to add a dispersion aid to the heat-melting coloring material layer of the present invention, its addition is not prohibited. As the dispersion aid, one or more types may be selected from commercially available ones. Examples of commercially available products include Solsperse 17000, Solsperse 22000 (manufactured by ICI), Nitsusan Polyster, and Nitsusan Fu. Examples include ylanol, Nitsusan Bremmer (manufactured by NOF Corporation), and the like.

The composition ratio of the heat-fusible colorant layer of the present invention is not limited, but the heat-fusible substance is 10 to 80% of the total solid content of the heat-fusible colorant layer (100% by weight, hereinafter the same).
% (more preferably 20-50%), colorant is 5-30%
% (more preferably 10 to 20%), thermosoftening polymer compound 6 to 20% (more preferably 8 to 15%), and the substance of the present invention 5 to 60% (more preferably 10 to 50%).
%, preferably the additive is 0-10%.

In addition to the above-mentioned components, the heat-melting coloring material layer of the present invention may contain various additives. For example, vegetable oils such as castor oil, linseed oil, olive oil, animal oils such as whale oil, and mineral oils may be suitably used.

The hot-melt coloring material layer of the present invention is preferably provided on an adhesive layer, and the adhesive layer may be any layer as long as it has adhesive properties to both the support and the hot-melting coloring material layer. Ingredients include ethylene-ethyl acrylate resin, ethylene-vinyl acetate resin,
One or more kinds of polymer compounds such as polyvinyl butyral and polyester can be arbitrarily selected and used.

In the heat-sensitive transfer recording medium of the present invention, techniques suitable for coating the heat-melting coloring material layer on the support or adhesive layer are known in the art, and these techniques can also be used in the present invention. I can do it. For example, the hot-melt coloring material layer can be formed by hot-melt coating the composition, or by solvent coating a coating solution obtained by dissolving or dispersing the composition in an appropriate solvent. As a method for applying the heat-melting color material layer of the present invention, any technique such as a reverse roll coater method, an extrusion coater method, a gravure coater method, a wire bar coating method, etc. can be adopted. As for the method of applying the adhesive layer used in the preferred embodiment of the present invention, any technique such as the above-mentioned solvent coating method or wire bar coating can be employed.

Although the thickness of the heat-melting coloring material layer of the present invention is not definitive, it is preferably 3 to 20 μm, more preferably 5 to 15 μm. Further, the thickness of the adhesive layer is not limited, but it is preferably 0.1 to 2 μm, more preferably 0.2 to 1 μm.

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. As for heat resistance strength,
It is preferable that the support has strength and dimensional stability that will not soften or plasticize due to the heating temperature of a heat source such as a thermal head. It is desired that the color material layer contained therein has sufficient smoothness to exhibit a good transfer rate. Examples of materials include papers such as plain paper, condenser paper, laminated paper, and coated paper;
Alternatively, polyesters such as polyethylene and polyethylene terephthalate, resin films such as polystyrene, polypropylene, and polyimide, paper-resin film composites, and metal sheets such as aluminum foil are all suitably used. The thickness of the support is generally preferably about 60 μm or less, more preferably 1.5 to 15 μm, in order to obtain good thermal conductivity. The heat-sensitive transfer recording medium of the present invention may have other constituent layers such as an overcoat layer (for example, a protective layer), and the structure on the back side of the support may be optional, and may be used to prevent staking. A backing layer such as a layer may also be provided.

[Effects of the Invention] According to the present invention, it is possible to print multiple times with high print density and good print quality even on transfer paper or sheets with low surface smoothness.

[Example] Examples will be given below, but the present invention is not limited thereto. In addition, "part" used below
indicates "parts by weight".

Example 1 The following composition was applied onto a 3.5 μm thick polyethylene terephthalate film using a wire bar and dried with air at 80°C. In this way, an adhesive layer with a dry thickness of 1.0 μm was obtained.

Ethylene-ethyl acrylate resin (NUC6070
(manufactured by Nippon Unicar Co., Ltd.) 4 parts xylene 96 parts Next, the following composition was dispersed and mixed at 100° C. for 5 hours using a sand mill.

Carbon black 14 parts paraffin wax (HNP-3 manufactured by Nippon Seirosha)
20 parts polyethylene wax (Weissen 0252C, manufactured by Nippon Seiro Co., Ltd.) 16 parts α-olefin-maleic anhydride resin (Diakaruna 30, manufactured by Mitsubishi Kasei Co., Ltd.) 20 parts ethylene-vinyl acetate resin (NUC 3160, manufactured by Nippon Unicar Co., Ltd.) 10 parts This dispersion was added to hexaglycerin pentasteate (Hexagrin 5S, manufactured by Nikko Chemicals).
After adding 20 parts and mixing with a dissolver for 10 minutes, hot-melt coating was performed on the contact layer with a wire bar to obtain a heat-sensitive transfer recording medium of the present invention having a heat-melt coloring material layer with a thickness of 12.0 μm. Ta. Print this using a serial thermal printer at 0.6mj/
Solid black printing was performed using dot energy.
At this time, the transfer paper has a Beck smoothness of 200 seconds.
Printing was performed using two types of transfer paper: high-quality paper with a speed of 30 seconds and copy paper with a speed of 30 seconds. As a result, on both transfer papers, there was little decrease in density up to 4 times, and high-density printing was possible. Figure 1 (Beck smoothness
200sec) and Figure 2 (Beck smoothness 30sec)
) shows the result.

Example 2 An adhesive layer was coated on a film support in exactly the same manner as in Example 1. On the other hand, the following composition was dispersed at 100° C. for 5 hours using a sand mill.

Carbon black 14 parts paraffin wax (HNP-3 manufactured by Nippon Seirosha)
20 parts carnauba wax 24 parts α-olefin-maleic anhydride resin (Diacarna 30 manufactured by Mitsubishi Kasei Corporation) 20 parts ethylene-vinyl acetate resin (NUC 3160 manufactured by Nippon Unicar Co., Ltd.) 10 parts Polyethylene glycol distearate is added to this dispersion. (The number of ethylene oxide parts is 10) 12
After mixing with a dissolver for 10 minutes,
Hot-melt coating was performed on the adhesive layer using a wire bar to obtain a heat-sensitive transfer recording medium of the present invention having a heat-melt coloring material layer with a thickness of 12.0 μm.

The printing results obtained in the same manner as in Example 1 are shown in FIGS. 1 and 2.

Comparative Example 1 The same process as in Example 1 was carried out except that the same amount of paraffin wax was added instead of hexaglyceryl pentastearate, and a thermal transfer recording was made with an adhesive layer thickness of 1.0 μm and a colorant layer thickness of 12.0 μm. Got the medium. When printing was performed using this in the same manner as in Example 1,
It has low density and also reduces the surface smoothness of the transfer paper.
In the case of 30 seconds, the repeatability decreased. That is, the printing results are as shown in FIGS. 1 and 2.

Comparative Example 2 In Example 1, instead of hexaglyceryl pentastearate, 20 parts of polyethylene glycol monostearate (number of ethylene oxide moieties: 55), which is incompatible in the range of 20°C to 100°C, was added to liquid paraffin. was treated in exactly the same way, and the adhesive layer thickness was 1.0μ.
A heat-sensitive transfer recording medium with a color material layer thickness of 12.0 μm was obtained. When printing was carried out using this in the same manner as in Example 1, although printing was possible at a high density for 200 seconds, the multi-printability sharply decreased for 30 seconds on paper. That is, the printing results are as shown in FIGS. 1 and 2.

Comparative Example 3 The same process as in Example 1 was carried out except that the same amount of sodium dodecylbenzenesulfonate was added instead of hexaglyceryl pentastearate, and a film with an adhesive layer thickness of 1.0 μm and a colorant layer thickness of 12.0 μm was obtained. A thermal transfer recording medium was obtained. When printing was carried out using this in the same manner as in Example 1, it was possible to print at high density for 200 seconds, but the multi-printability sharply decreased for 30 seconds on paper. That is, the printing results are as shown in FIGS. 1 and 2.

[Brief explanation of the drawing]

Figures 1 and 2 are graphs showing the relationship between the number of prints and optical reflection density for samples ~ in Examples and Comparative Examples;
Figure 2 shows the case of printing on a transfer paper with a surface smoothness of 30 seconds.

Claims (1)

[Scope of Claims] 1. A heat-sensitive transfer recording medium that has a heat-melting coloring material layer on a support and can be used multiple times, wherein the heat-melting coloring material layer is represented by the following general formula (1). A thermal transfer recording medium characterized by containing at least one kind of polyglycerin fatty acid ester or polyethylene glycol fatty acid ester represented by the following general formula (2). General formula (1) In the above formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ each may be the same or different and represent a hydrogen atom or an acyl group having 6 to 30 carbon atoms, and n is an integer of 1 to 20. General formula (2) In the above formula, R ₆ and R ₇ may be the same or different,
It represents an alkyl group, an alkenyl group, or an aralkyl group having 6 to 30 carbon atoms, and n is an integer of 1 to 20.