JPS6025788A - Heat transfer material - Google Patents

Abstract

PURPOSE:To provide a heat transfer material imparting a good recording image even to a recording medium with poor surface smoothness, obtained by forming a thermal transfer ink layer, which is prepared by dispersing a sublimable dye and a microcapsule containing a liquid - semi-solid oil agent in a heat-meltable binder, on a support. CONSTITUTION:A sublimable dye (e.g., 1,4-diamino-2,3-dichloro-anthraquinone) and microcapsules 5 each containing an oil agent liquid - semi-solid at an atmospheric temp. (e.g., cotton seed oil or lanolin) are dispersed in a heat- meltable binder 4 such as carnauba wax. This dispersion is applied onto a support 2 comprising polyester to obtain the objective thermal transfer material having a heat transfer layer 3 with a thickness of, pref., 2-20mum formed thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive transfer material that can produce transferred recorded images having good print quality and storage stability even on recording media with poor surface lubricity.

In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording methods and devices suitable for each information processing system have also been developed and adopted. One such recording method is the thermal recording method.
The equipment used is lightweight, compact, noiseless, and has excellent operability and maintainability, and has recently been widely used.

However, among the recording papers used in thermal recording methods, ordinary thermal recording paper is a color-forming processed paper that contains a color former and a color developer, so it is expensive and records can be tampered with. , the recording paper may easily develop color due to heat or solvents,
It has disadvantages of poor storage stability, such as discoloration of recorded images over a relatively long period of time.61: As a method that maintains the advantages of the thermal recording method described above and eliminates the disadvantages associated with the use of thermal recording paper, Thermal transfer recording method, which has recently been attracting a lot of attention, generally uses a thermal transfer ink made by dispersing a coloring agent in a heat-melting binder on a sheet-like support L. Using a heat-sensitive transfer material formed by melt coating 41, this heat-sensitive transfer material is superimposed on a recording medium so that its heat-transferable ink layer is in contact with the recording medium, and heat is supplied from the support side of the heat-sensitive transfer material by a thermal head. By transferring the melted ink layer onto the recording medium, a transferred ink image is formed on the recording medium according to the shape of the heat supply.

According to this method, the advantages mentioned above of the thermal recording method can be
It is possible to use E-bearing 11 pif paper as a recording medium, and the drawbacks associated with the use of heat-sensitive recording paper mentioned in 1. can also be eliminated.

However, conventional thermal transfer recording methods are not without drawbacks. This is because in the conventional thermal transfer recording method, the transfer recording performance, that is, the printing quality, is greatly affected by the surface 11 smoothness, and although good printing is performed on recording media with high IP slippage, recording with low smoothness In the case of media, the print quality deteriorates significantly. However, even when using paper, which is the most typical recording medium, #l (with high smoothness) is rather special, and ordinary paper has various degrees of unevenness due to the entanglement of fibers. In the case of large paper, the hot melted ink cannot penetrate into the fibers of the paper during printing, and sticks only to the convex parts of the surface or the vicinity thereof, resulting in sharp edges of the printed image. The image may be missing, or part of the image may be missing, resulting in a decrease in print quality.

It has also been proposed to incorporate a 1≠+1 dye into a heat-melting binder, but in this case, the heat transfer ink only sticks to the surface of the recording medium and the dye sublimes from the surface. Since the +1 color does not come from within the m## structure of the recording medium, extremely high energy heat must be applied to dye the fibers deep within the Mt structure, and in fact -1 This method has the disadvantage that only a printed image that lacks sharpness at the edges can be printed. Furthermore, in order to improve print quality, it is possible to use a heat-melting binder with a low melting point;
The printing ink layer becomes sticky even at a relatively low temperature, resulting in problems such as low if retention properties and staining of the recording medium at the II print area.

The main object of the present invention is to eliminate the drawbacks of the conventional thermal transfer recording method described above, and to provide high quality recording media not only for recording media with good surface smoothness but also for recording media with poor surface smoothness. J71 is a thermal transfer material that can give prints with excellent storage stability. It is about providing.

According to the research of the present inventor, in order to achieve L1, it is necessary to add (1) dyestuff (1) to the heat-melting binder constituting the heat-transferable ink layer, which is liquid or semi-solid at room temperature. It has been found that dispersing microcapsules containing an oil agent is extremely effective. When the heat-transferable ink layer thus formed is heated while being in contact with a recording medium placed on a platen, the heat-melt binder in the heat-transferable ink layer melts or softens and the heat-transferable ink layer is heated. is transferred to the recording medium, the microcapsules in the thermal transfer ink layer are destroyed by the pressure from the platen, and the penetrating power of the built-in oil agent
The irradiant dye penetrates into the #ll fiber structure of the recording medium. Here, by the heat during transfer, or by further heating the recording medium to a temperature higher than 1 F of the dye, the &7 florescent dye is oxidized inside the fiber structure.
The fiber MF itself is strongly dyed r1. Therefore, even on a recording medium with poor surface smoothness, it is possible to obtain a recorded image with good print quality and good storage stability without defects in the printed image.

The thermal transfer material of the present invention is based on the above-mentioned technique, and more specifically, a thermal transferable ink layer is formed on a support, and the thermal transferable ink layer is It is characterized by dispersing microcapsules containing Y1 Shin P1 Sensai'1 and an oil agent that is liquid or semi-solid at room temperature in heat-melting pinter.

Hereinafter, the present invention will be described in more detail with reference to the drawings. “%” represents the paper ratio in the following descriptions.
and "part" shall be based on the mold part unless otherwise specified in 4I+.

Figure t51 is a schematic cross-sectional view in the thickness direction of a thermal transfer material in the most basic embodiment of the present invention. That is, the heat-sensitive transfer material 1 is formed by forming a heat-transferable ink layer 3 on a support 2, usually in the form of a sheet (used to include a film).

As the support 2, conventionally known films and papers can be used as they are, such as films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetyl cellulose, nylon, and polyimide, cellophane, or sulfur M 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 during thermal transfer. (There are no particular restrictions on the use of silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, By providing a heat-resistant protective layer made of nitrocellulose or the like, the I8 properties of the support can be improved, or it is also possible to use a support material that could not be used conventionally.

Thermal transferable ink layer 3 is in the heat-melting binder 4!
It consists of a coating layer of heat-melting ink in which microcapsules 5 containing dye oil and an oil agent are dispersed,
If necessary, it is also possible to add additives such as a 6-part coloring agent, a dispersant, a filler, etc. into the microcapsule, or to further add a coloring agent, filler, oil agent, etc. to the heat-melting binder. Further, although not particularly shown in the drawings, an intermediate adhesive layer may be provided in order to strengthen the adhesion between the support 2 and the thermal transferable ink layer 3.

Heat-melting binders include carnauba wax, paraffin wax, Zazol wax, microcrystalline wax, Castor Wankutsu's waxes on the left: stearic acid, palmitic acid, lauric acid, stearin butylaminium 11, stearin lead-resistant, Derivatives of barium stearate, zinc stearate, zinc palmitate, methylhydroxystearate 1, glycerol monohydroxystearate, 14th fatty acids or their metal salts, esters); polyethylene, polypropylene, polyester. Isobutylene, polyethylene wax, alcoholic acid, polytetrafluoroethylene, ethylene-acrylic acid copolymer, ethylene-acrylic ethyl copolymer, ethylene-vinyl acetate compound A. Thermoplastic resins made of these derivatives, etc. are used. These heat-melting binders can be used alone or in combination of two or more.

The microcapsule 5 contains at least a Cq flower dye and an oil agent that is liquid or semi-solid at room temperature.

'y4 ='l'i sex dyeing'l is 150-20
Y1 flower in the warm range of 0℃! For example, a dye that emits to the dye is used, and is selected from among disperse dyes, Jl-based dyes, oil-soluble dyes, and the like. Examples include 1,4-diamino-2,3-dichloro-anthraquinone, 1-amino-2-phenoxy-4-hydroxy-anthoquinone, 3-hydroxyquinophthalone, -amino-2
-Cyano-4-anilide-anthraquinone, 1,4-sivitrow-5-amino-8-isopropylamino-anthraquinone, and the like. These +jl flower dyes are
Used in China and Germany or in combination of two or more types.

Oils include those that are liquid at room temperature, such as animal and vegetable oils such as cottonseed oil, rapeseed oil, and whale oil; motor oil,
Mineral oils such as spindle oil and dynamo oil are used, and semi-solids such as lanolin, vaseline, and lard are used.

Waxes with a softening point or melting point of 60°C or higher,
Higher fatty acids or their gold salts, esters, etc.:A
Conductive thermoplastic PItI+1 resin etc. can also be used.

In order to prepare the thermal transfer agent A of the present invention, first, the above-described sublimable dye, oil agent, and other additives added as necessary are kneaded to form a dye paste, and this is microencapsulated. do.

The oil agent is 2 to 1 parts for 0 parts of eyebrow dyeing.
It is preferably used in a proportion of 200 parts, especially 5 to 100 parts.

15) To make microcapsules, write 1-! In addition to the easy method of dispersing Itasomesai 1 paste in a solution of incompatible resin and spray drying the dispersion, it is also possible to easily use Conventional methods for microencapsulation such as the injection method and the interfacial method are appropriately employed. Further, as the wall material resin, a resin which is preferably incompatible with the heat-melting binder is appropriately selected from known thermoplastic resins or thermosetting resins suitable for these microencapsulation methods.

Microcapsules with a diameter of 0.1-10°, especially 2
~511. The later one is preferable and can be used. The thickness of the coating resin is preferably in the range of 0.1 to 0.5 #L.

Then, for every 10 parts of the microcapsules thus prepared, 2 to 100 parts, preferably 5 to 100 parts,
Uniformly disperse in 100 parts of a melt, solution, or dispersion of a hot-melt binder, apply this dispersion onto a support z using a hot melt coater or a solvent coater, and cool or dry as necessary. The thickness is 1 to 30 JL, preferably 2 to 20 I1. By forming the thermal transferable ink layer 3, the thermal transfer material of the present invention can be obtained.

The planar shape of the thermal transfer material of the present invention is not particularly limited, but it is generally used in the form of a typewriter ribbon or a wide tape used in line printers. Further, for color recording, it is also possible to use a heat-sensitive transfer material in which heat-melting ink of several tones is applied separately in stripes or blocks.

Next, an example of a thermal transfer recording method using a J-bis thermal transfer material will be described. FIG. 2 is a schematic cross-sectional view in the thickness direction of the thermal transfer material showing the N essential point. That is, the heat-melting ink fi3+ of the thermal transfer material 1 is brought into close contact with the recording medium 6, and while applying pressure from the back side of the recording medium with the platen 7, a heat source such as a thermal head or a laser heater is applied from one side of the support 2. A heat pulse is applied by 8 to locally heat the ink layer 3 in accordance with a desired printing or transfer pattern.

When the heated portion of the ink R3 reaches a certain temperature, it softens or melts, resulting in a decrease in viscosity. the result,
The microcapsules 4 are destroyed by the pressure from the platen 7, and the paste of the built-in dye is transferred to the recording medium 6 together with the softened or melted binder, leaving a transfer ink 9.3 a. Due to the permeability of the built-in paste, paste permeation portions 3b are formed into the recesses of the recording medium or the inside of its fibrous structure, which could not be permeated with conventional hot-melt inks. Here, if necessary □, an additional heat source 9 is used to transfer the transferred ink images 3a, 3.
By heating b to a sublimation temperature tool for a sublimable dye, the infiltrated dye sublimes and a dyed portion 10 extending deep into the recording medium is formed.

As described above, according to the thermal transfer material of the present invention, the surface smoothness is improved by microcapsulating and dispersing the A flower dye and the oil agent, which is liquid or semi-solid at room temperature, in the thermal transfer ink layer. It is possible to provide a transferred recorded image having good print quality and storage stability even on a recording medium with poor quality. Furthermore, the storage stability of the thermal transfer material itself is maintained well.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Actual Example: 5 parts of Zapon Fast Yellow, 5 parts of 3-/\hydroxyquinophthalone, 20 parts of rapeseed oil, and 5 parts of lecithin were kneaded using a Miki roll to prepare A flower dye paste. 35 g of this paste and 0.2 g of terephthaloyl chloride were mixed with 200 g of 0.5% aqueous sodium bicarbonate solution.
Using a homomixer in m1, the oil was emulsified and dispersed so that the diameter of the oil droplets was 1 to 2 IL. Stir) 10% while continuing ↑
After adding 5Qml of ethylene glycol aqueous solution and continuing stirring for 10 minutes, spray-drying using a spray dryer produces particles with a diameter of 1~211. 1 microcapsule! I was.

Separately, 1 part of polyethylene wax (softening point approximately 95°C),
2 parts of paraffin wax (softening point: about 70°C) and 1 part of carnauba wax were heated and stirred at about 120°C and mixed together. Then, 16 parts of a petroleum solvent (trade name: Isopar H, manufactured by Esso) was added, and about The mixture was heated to 100° C. and cooled to room temperature with vigorous stirring to obtain a fine dispersion of the workpiece.

A coating solution obtained by mixing and stirring 20 parts of this fine dispersion of wax and 4 parts of the microcapsules described above was applied to a polyester film with a thickness of 6 months, and dried to a thickness of 1 month.
A thermal transfer material having a thermal transfer ink layer of O11 was obtained.

Using this thermal transfer material, an applied pressure of 1.6 kg/Cnf' and an applied pulse I were applied to a recording paper with a Beck smoothness of 30 sec.
When heating recording was performed using IJ5 msec, a bitter-colored recorded image was obtained, which was almost the same size as the heating element.

The recording paper on which the recorded image was formed in this way was irradiated with infrared rays and heated to a temperature higher than the temperature required for dyeing. A recorded image was obtained.

Comparative Example Add 0.5 part of Zapon Fast Yellow and 0.5 part of 3-hydroxyquinophthalone to the wax fine dispersion obtained in Example.
of the mixture and stirred vigorously using a homomixer to obtain a coating solution. A heat-sensitive transfer material was obtained using this coating liquid in the same manner as in Example 1, and as a result of recording, chipping was observed in the transfer area. When the image was further heated, the edges of the image appeared blurred and lacked sharpness.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view in the thickness direction of an embodiment of the thermal transfer material of the present invention, and FIG. 2 is a thermal transfer diagram for explaining eight punches of the thermal transfer recording method using the thermal transfer material of FIG. 1. It is a stopper type sectional view seen in the thickness direction of the material. 1...Thermal transfer material 2...Support 3...After the fully transferable ink (3a...Recording ink image, 3b--The part where the ink paste penetrates into the recording medium) 4...Thermal meltability Binder 5...Microcapsule 6...Recording medium 7##Q's Latin 8 book...Heat source

Claims (1)

[Claims] A thermally transferable ink layer is formed on the supporting body-1. liA thermal transfer P1: The ink layer is characterized by dispersing microcapsules containing S1 flower dye 1 and an oil agent that is liquid or solid at room temperature in a heat-melting binder. Thermal transfer material.