KR900007779B1 - Thermal transfer recording medium - Google Patents

Abstract

A recording medium has thermo-fusible type or sublimation type ink layer on para-oriented aromatic polyamide film of thickness 1-8 microns. Young's modulus at least in one direction of the polyamide film is at least 600 kg/mm2, and the polyamide film hardly contains chlorine atom. Thermo-fusible ink layer comprises 1 wt.% of thermo- fusible ink and 0.5-40 wt.% of binder, of thickness 1-20 microns. Binder is, e.g., polyester resin, epoxy resin, styrene resin, polycarbonate resin, ethyl cellulose, etc. Sublimation type ink layer comprises 100 wt.% of sublimative dye and 30-600 wt.% of binder. The recording medium is used for thermal printer, thermal typewriter, video printer, etc.

Description

Thermal transfer record carrier

INDUSTRIAL APPLICABILITY The present invention is used for recording apparatuses such as thermal printers, thermal typewriters, and video printers, and the thermally meltable or thermal sublimable ink is gradually transferred to a container such as a recording sheet by heating by a thermal head, and can be printed. A thermal transfer recording medium.

Conventionally, a recording medium of this kind has been used in which a heat-melting ink layer is provided on a polyethylene terephthalate (PET) film. However, the PET film lacks thermal dimensional stability and has a melting point of about 260 ° C., which is deteriorated and deformed by the thermal head when heated to about 250 to 300 ° C., so that it is only one-time use, and in special cases, melting Problems such as being cut off were likely to occur.

For this reason, as an example, in Unexamined-Japanese-Patent No. 61-86288, it is proposed to use the aromatic polyamide film excellent in heat resistance as a base film. However, the publication specifically points to poly-m-phenyleneisophthalamide as the most preferred aromatic polyamide, and all examples also use this meta-orientated aromatic polyamide film. By the way, although poly-m-phenylene isophthalamide is excellent in heat resistance, in the case of the thin film of 8 micrometers or less useful for a heat transfer base film, since the film is low in Young Modulous, the thin film itself Because of its weakness, handling is difficult at the time of manufacture and at the time of use, and there is a drawback of lighting that the yield at the time of manufacture decreases.

Moreover, Japanese Patent Laid-Open No. 61-237687 proposes to use a halogenated aromatic polyamide film as a base film. However, since the center of gravity is a nonparametric aromatic polyamide containing a flexible bond, the Young's modulus is small, and has the same drawbacks as those described in the above publication. Moreover, since it is an aromatic polyamide which essentially contains a halogen atom centering on a chlorine atom, it has a drawback that an ink layer may deteriorate, for example, when it is repeatedly heated using it as a use tape for many times.

The present invention has been made in view of such circumstances, and an object thereof is to provide a thermal transfer recording medium which solves the above-mentioned shortcomings.

MEANS TO SOLVE THE PROBLEM In the process of examining variously in order to achieve the said objective, the present inventors discovered that it is effective to make the para-aromatic aromatic polyamide film of high heat resistance and high Young's modulus in a special method, and to use this as a base film, The present invention has been completed.

That is, the present invention provides a heat-melt or heat-sublimable ink-containing layer on an aromatic polyamide film that is substantially free of chlorine atoms having a Young's modulus of at least one direction of 600 kg / mm ² and a thickness of 1 to 8 µm. Characterized in the thermal transfer recording medium.

In the present invention, as the heat-melt ink, one having the same component as that conventionally used as a solid ink of a heat transfer recording medium can be used. In particular, the viscosity at a temperature of 30 DEG C higher than the melting temperature is 10 to 500 cp (B As a measured value by a type | mold viscosity meter, it is suitable that melt temperature is 50-120 degreeC. As a coloring agent of a heat-melting ink, not only black pigments, such as carbon black, but also coloring agents, such as blue, red, and sulfur, may be made to form an impression of a color. As such a colorant, any of those used in a conventional one-time thermal transfer recording medium can be used.

The heat meltable ink is usually adhered to an aromatic polyamide film by a binder agent.

The binder agent is preferably non-compatible or poorly compatible with the heat-melting ink, has adhesion to the aromatic polyamide film, and does not melt by heating of the thermal head. For example, polyester Examples of the resin include an epoxy resin, a styrene resin, a polycarbonate resin, a cellulose acetate butyrate, an ethyl cellulose and a polyamideimide resin, and a thermomelt resin or a thermosetting resin having a softening point of 70 ° C or higher. These resins may be used independently and may use 2 or more types together. Moreover, 1 type (s) or 2 or more types may be added suitably according to the objective with a suitable additive.

It is suitable to mix these binder agents at 0.5-40 weight part with respect to 1 weight part of said heat meltable inks.

As the recording medium of the present invention, a multi-use type is a preferred embodiment. As such an example, the incompatible resin is used with respect to the heat-melting ink, and the fine powder having a structure in which the ink is contained in the sponge layer formed as the resin, and the cohesive fine powder are mixed with the ink, and the fine powder is used. And a barrier layer formed by agglomeration of, and the porous powders impregnated with the hot melt ink are mutually bonded by a binder agent which is substantially incompatible with the hot melt ink.

Examples of the porous powder include inorganic porous powders such as diatomaceous earth, zeolite and bentonite, and organic porous powders such as urethane bore powder and the like.

The method of providing the heat-melting ink-containing layer on the film is not particularly limited and can be carried out by a known method. For example, in a state in which the ink is hot melted, it is mixed with the binder solution (the solvent used preferably dissolves the hot melt ink and the porous powder hardly), and is applied to a film, dried and the ink The containing layer is formed. As for the thickness after drying of the said ink layer, 1-20 micrometers is suitable.

The heat sublimable ink-containing layer is composed of a heat sublimable dye and a binder, and dissolves or disperses the sublimation transfer dye and a binder in a suitable solvent to prepare a coating solution, and the prepared coating solution is para-oriented aromatic polyamide. It can obtain, for example, by apply | coating and drying to one surface of a film so that it may become a dry film thickness of about 0.2-5.0 micrometers.

As a dye useful for the formation of such a thermal sublimation transfer layer, conventionally known ones can be used. Particularly preferred in the present invention are those having a small molecular weight of about 150 to 400. Sublimation temperature, color, light resistance, ink and It selects in consideration of solubility, dispersibility, etc. between binder agents. Specifically, it is used as a disperse dye conventionally, for example, and it is preferable as a iketone. Polyester. Yellow-YL (Mitsudo Oatsu, CI disperse. Yellow-42), Myketone. Polyester. Yellow-5G (Mitsuido Oatsu making, CI dispers, yellow-5), Kaya set.Yellow-G (Nippon Kayakaku manufacture, CI solvent.Yellow-77), Kaya set.Yellow-N (Nippon Kayakaku production, CI solvent Yellow-25 (S)), PTY-52 (Mitsubishi Chemical Corporation, CI Disperse.Yellow-14-1), PTY-56 (Mitsubishi Chemical Corporation, CI Dispersion.Yellow-3), Myketone. Polyester.Red.BSF (Mitsuido Oatsu, C.I.Dispers.Red 111), Mytone. Polyester red T3B (made by Mitsui Ooatsu, C.I. dispers. Red 228 (S)). Kaya set red B (Nippon Kayakaku production, CI disus red 135), Kaya set red 126 (Nippon Kayakaku production, CI dispers Red 4), PTR-54 (CI dispers Red 50), PTR-63 (Mitsubishi Kasei production, CI dispers red 60), iketone.Polyester blue -FBL (Mitsuido oatsu, CI dispers blue -56), discharge.Blue-R (Mitsuido oatsu, CI dispers Blue -106), Mitsui PS blue -3R (Mitsuido Oatsu, CI Disperse Blue -33), PTB-67 (Mitsubishi Chemical Corporation, CI Dispers Blue -241), PTB-77 (Mitsubishi Kasei, CI solvent blue -90), Kaya set blue -906 (made by Nippon Kayakaku, CI solvent blue -112), Kaya set blue -141 (manufactured by Nippon Kayaku, CI solvent blue -114 (S)), etc. are mentioned. .

In addition, as the binder agent, those having high heat resistance among the conventionally known binder resins and which do not hinder the transfer of dyes when heated, are selected. For example, as the cellulose resin, ethyl cellulose hydroxyethyl cellulose and ethyl hydroxide are selected. Polyvinyl alcohol, polyvinyl acetate, polyvinyl butylal, polyvinylpyrrolidone, polyester, polyacrylamide, etc. are mentioned as vinyl-type resin, such as hydroxycellulose, hydroxypropyl cellulose, methyl cellulose, and acetylacetic acid cellulose. .

Such a binder agent is good to use in the ratio of about 80-600 weight part per 100 weight of dye, for example.

As the ink solvent for dissolving or dispersing the dye and the binder agent in the present invention, conventionally known ink solvents can be freely used. Specifically, alcohol, methanol, ethanol, isopropyl alcohol, butanol, isobutanol And the like, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like, toluene, xylene, and the like, dichloromethane, trichloroethane, and the like, dioxane, tetrahydrofuran, and the like. And mixtures thereof. It is important to select and use these solvents as the thing which melt | dissolves or disperse | distributes the said dye to be used more than predetermined concentration, and the said binder resin fully. For example, it is good to use about 9-20 times the solvent of the total weight of the said dye and binder resin.

The aromatic polyamide film used in the present invention is a film made of a para-oriented aromatic polyamide containing substantially no chlorine atoms. And preferably consists substantially as poly-p-phenyleneterephthalamide (PPTA). When the aromatic polyamide film containing chlorine is used as the base film, the ink-containing layer may cause thermal deterioration, and in particular, it is difficult to secure uniform and vivid printing in a multi-use type.

The film has a Young's modulus of at least one direction of 600 kg / mm ² or more. There are two aspects of the film used in the present invention, one of which is a balanced type having almost the same Young's modulus in the longitudinal direction and the transverse direction of 600 kg / mm ² or more, and one of the longitudinal and the transverse directions. It is a tensilized type that has a large Young's modulus of 600 kg / mm ² or more. Such a film having a large Young's modulus in at least one direction means a large deformation resistance in that direction, and is also related to the strength of the property of the film. Strength is an important factor, especially for thin films. The film used for this invention, Preferably it has a Young's modulus of 800 kg / mm <^2> or more, More preferably, the Young's modulus which is 1000 kg / mm <^2> or more in at least one direction.

If the polymerization degree of the polymer constituting the film used in the present invention is too low, a film having good mechanical properties cannot be obtained. Therefore, a logarithmic viscosity ηinh of 3.5 or more and more preferably 4.5 or more is dissolved by dissolving 0.5 g of polymer in 100 ml of sulfuric acid. The thing of the degree of polymerization which gives the numerical value measured at 30 degreeC) is selected. Moreover, as for the film used for this invention, the thing whose thickness is 8 micrometers or less is selected. When using a thickness of more than 8 μm, there is no advantage of using an aromatic polyamide film.

As for film thickness, the thing of 1 micrometer or more is used normally. In addition to the problem that it is difficult to handle a film that is too thin, the degree of poor deformation as a tape is determined as (Young's modulus) x (thickness) ^3. Therefore, in order to realize a tape having a strain resistance, it is necessary to make the Young's modulus very large. Because they are in trouble. As for the film used for this invention, it is more preferable to have thickness of 2-5 micrometers.

The film used for this invention, Preferably, it has high transparency and smooth flatness. As high transparency, the visible light transmittance of the wavelength of 600 nm, for example, preferably has 55% or more, More preferably, it has 70% or more.

Moreover, the film used for this invention, Preferably, it does not contain a void substantially.

In addition, the film used in the present invention preferably has an elongation of 8% or more, more preferably 15% or more in any direction.

Among the films used in the present invention, in particular, PPTA films have a high tear resistance, for example, a tear propagation resistance of at least 150 g / mm, more preferably at least 200 g / mm, at least 1 kgf, preferably at least 2 kgf of adiabatic resistance. Therefore, even a thin film having good thermal transfer performance is very good at the time of manufacture and use of slitting or the like and is not easily torn.

In addition, in the present invention, especially when a PPTA film is used, it is found that the thermal conductivity is very excellent, and there is a remarkable improvement in shortening of the thermal transfer time, saving of thermal transfer energy (power consumption), and sharpening of printing. okay.

The film used in the present invention is required to pour optically anisotropic dope containing sulfuric acid or the like on a support surface, invert the dope to optically isotropic by moisture absorption or heating and coagulate therein, and then wash it. According to the invention, it can be produced by a special method of stretching one axis or two axes and then drying while limiting shrinkage.

The film used for this invention can be used by vapor-depositing or laminating a metal to the one surface or both surfaces. Moreover, you may make carbon black, alumina, etc. contain in a film in order to improve the thermal conductivity of a film further.

Next, an Example is given and this invention is demonstrated.

Reference Examples 1 to 3

A PPTA polymer having a? inh of 5.5 was dissolved in 99.7% sulfuric acid at a polymer concentration of 11.5% to obtain dope with optical anisotropy at 60 ° C. It was 10600 poise when the viscosity of this dope was measured at normal temperature. In order to make film formation easy, this dope was degassed under vacuum, maintaining at about 70 degreeC. At this time, it had optical anisotropy similarly to the above, and the viscosity was 4400 poise. A tantalum belt (12 m /) polished like a mirror surface from a die having a 1.5 m bent tube to a die via a filter from a tank to a die via a starp pump at about 70 ° C. and having a slit of 0.1 mm x 300 mm. And air at about 90 ° C. with a relative humidity of about 85%, optically isotropicized and guided into the water at 5 ° C. with the belt to solidify. Then, the coagulation film is removed from the belt and washed by running in about 40 ° C of warm water. The washed film was stretched with a tender without rolling, and then hot air dried at a constant length at 240 ° C. using another tender.

Table 1 summarizes the sampling results by varying the discharge linear velocity and the draw ratio from the die.

Table 1

Examples 1 to 3

The hot melt ink shown in Table 2 was mixed with the porous powder shown in Table 3 and impregnated with a vacuum impregnation apparatus. Next, the porous powder impregnated with the ink is mixed with the binder solvent shown in Table 3 in the state where the ink is hot melted, and the obtained mixed solution is applied onto the film shown in Table 3, and then dried to remove the solvent. A recording medium having an ink containing layer of the indicated thickness was produced.

Table 2 (Thermal Melt Ink)

TABLE 3

The thermal transfer recording media of Examples 1 to 3 were used in a thermal printer (WP-55) manufactured by Canon Corporation, printed 10 times on a white recording paper using the same location of the recording media, and then based on a commercial PET film. Compared with the factors by the recording medium. In the recording medium of any embodiment, up to 5 to 7 prints were clearer than the first print of the PET film-based print medium. In addition, in the PET film-based recording medium, the printing medium of Examples 1 to 3 had a degree of clarity that can be used even in the tenth printing, while the printing medium could not be normally printed after the second time.

Example 4

The following ink-containing layer containing a heat sublimable disperse dye was applied and dried on the film of Reference Example 2 so that the coating weight at the time of drying was 1.0 g / m ² , to prepare a recording medium of the present invention.

Composition of Ink-Containing Layer

Disperse Dyes (Nippon Kayaku Co., Ltd., Gaya Set Blue-814), Part 4

4.5 parts of polyvinyl butyl resin

Xylene 45

Methyl ethyl ketone 35 parts

Isobutanol 10 parts

Subsequently, 150 μm-thick synthetic paper (manufactured by Oji Yuka, YUPO-FPG 150) was used, and the ink composition for an aqueous layer having the following composition was coated so as to have a thickness of 5 g / m ² at the time of drying to obtain a thermal transfer sheet. After drying, after drying as a dryer, it carried out in oven at 100 degreeC for 1 hour, and the solvent was fully volatilized.

Water soluble ink composition

8 parts of polyester resin

EVA plasticizer 2 copies

Amino Denatured Silicone Oil0.125part

0.125 parts epoxy resin

Xylene 70

Methyl ethyl ketone 10 parts

20 parts cyclohexane

The thermal transfer sheet and the thermal transfer sheet thus produced were stacked so that the thermal transfer ink-containing layer and the receiving layer were in contact with each other, and the recording was performed by the thermal head from the base film side of the thermal transfer sheet.

Sticking to the thermal head did not take place at all, and a coloration with the intended concentration distribution was obtained with a gradation corresponding to the applied energy to the thermal head.

Subsequently, the above-described ink-containing layers were prepared by using Gaya-set Yellow-G and Gaya-set Red 126 (manufactured by Nippon Kayakaku) as the disperse dye, respectively, to prepare a thermal transfer sheet. On the other hand, good results were obtained as in the case of the blue.

Therefore, if these three primary colors of thermal transfer sheets are used sequentially, arbitrary colors can be recorded (printed) for each of the shades.

According to the configuration of the present invention, since the para-oriented aromatic polyamide film is excellent in heat resistance, even when the recording medium is supplied to the thermal printer and used, the base film does not deform, deteriorate, or melt cut.

Moreover, since the Young's modulus is large, the strength is high even if it is made thin.

As a result, unlike conventional recording media using a PET film as a base film, only one time is used, the ink content can be sustained or used as a sponge layer structure or a binder. . In addition, there is no problem in use due to melt cutting or sticking of the tape. In addition, since the thermal head temperature can be higher than before, and the film is made thin, the strength is high, so that the printing speed can be increased and the sharpening can be achieved. In addition, since the Young's modulus of the para-oriented aromatic polyamide film is large, it is easy to make it thin, and although it is a thin film, the strength is large, the long-term use can be made long, and it is easy to handle.

Moreover, especially when a PPTA film is used, since heat resistance is large, the problem at the time of sticking, for example, at the time of manufacture of the recording medium of this invention is small, and a yield improves. Since PPTA film is excellent in thermal conductivity, it is easier to speed up and sharpen printing, and it is possible to save power consumption during thermal transfer.

Claims (1)

The thermal transfer or heat sublimation ink-containing layer is provided on a film made of poly-para-phenylene terephthalamide having a thickness of 1 to 8 µm and a Young's modulus in at least one direction of 600 kg / mm ² or more. Record carrier.