JPH058551A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To provide a co-wound thermal transfer sheet capable of forming an image of a color other than black and the three primary colors. CONSTITUTION:In a thermal transfer sheet wherein a thermal transfer sheet A formed by forming a hot-melt ink layer 2 to one surface of a base material film is bonded to a transfer material B in a releasable manner through an adhesive layer C, the ink layer 2 is colored by a colorant having a hue other than black and the three primary colors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer sheet, and more particularly to a novel co-rolled thermal transfer sheet in which a thermal transfer sheet and a transfer material such as paper are preliminarily adhered to each other.

[0002]

2. Description of the Related Art Conventionally, when printing an output print of a computer or a word processor by a thermal transfer method, a thermal transfer sheet having a heat-fusible ink layer on one surface of a base film is used. This conventional thermal transfer sheet is a substrate film having a thickness of 10 to 20 μm, such as condenser paper or paraffin paper, or a thickness of 3 to 20 μm.
This is manufactured by using a film of plastic such as polyester or cellophane having a thickness of .mu.m and coating a hot-melt ink layer in which a coloring agent such as a pigment or a dye is mixed with wax. When printing on a transfer sheet using these conventional thermal transfer sheets, the thermal transfer sheet is supplied from a roll around which the thermal transfer sheet is wound, while a continuous or sheet-shaped transfer material is supplied and both are placed on a platen. In this state, heat is applied from the back surface of the thermal transfer sheet with a thermal head to melt transfer the ink layer to form a desired image. However, these thermal transfer sheets, for example,
Even if you try to convert to a conventional facsimile printer using thermosensitive coloring paper, in the above facsimile printer,
Since the recording paper itself develops heat, it cannot be diverted because there is no transfer device for the material to be transferred.
The same applies to special printers. As a method of solving the above problems, a thermal transfer sheet and a transfer material are preliminarily adhered to each other and wound in a roll shape to adapt to a facsimile printer or the like, and also to simplify and downsize the apparatus. A method has been devised.

[0003]

In the case of such a co-rolled thermal transfer sheet, a black ink layer is mostly used as an ink layer, and ink layers of three primary colors of yellow, magenta and cyan are also known. However, when an image of black color and an intermediate color other than the above three primary colors is required for printing, it is not possible to perform overprinting of printing in the case of the co-winding heat transfer sheet, and therefore, image formation of these intermediate colors is not possible. It was impossible. Therefore, an object of the present invention is to solve the above problems and provide a co-rolling thermal transfer sheet capable of forming images other than black and three primary colors.

[0004]

The above object can be achieved by the present invention described below. That is, the present invention relates to a thermal transfer sheet comprising a substrate and a thermal transfer sheet having a heat-fusible ink layer formed on one surface of the substrate film, and a transfer-receiving material which are releasably adhered to each other by an adhesive layer. Is colored with a colorant having a hue other than black and the three primary colors.

[0005]

By coloring the ink layer of the thermal transfer sheet with a colorant having a hue other than black and the three primary colors, a desired intermediate color image can be formed even on the co-roll thermal transfer sheet.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in more detail with reference to the preferred embodiments. A cross-sectional view of a preferred example of the thermal transfer sheet of the present invention is shown in FIG. The thermal transfer sheet of the present invention is a thermal transfer sheet in which a thermal transfer sheet A and a transfer target material B are releasably adhered by an adhesive layer C as shown in the figure, and the ink layer of the thermal transfer sheet is an intermediate colorant. It is characterized by being colored. In the thermal transfer sheet A, as shown in the figure, a heat-fusible ink layer 2 is formed on a base film 1, a release layer 3 is provided between the base film 1 and the ink layer 2 if necessary, and a back surface. The slip layer 4 is formed on the.

As the base material film used in the thermal transfer sheet of the present invention, the same base material film as that used in the conventional thermal transfer sheet can be used as it is, and other materials can be used. Not limited. Specific examples of preferable substrate film include, for example, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber, ionomer and the like. Paper, such as plastics, condenser paper and paraffin paper, non-woven fabric, etc., and a base film in which these are compounded may be used. The thickness of the base film can be appropriately changed depending on the material so that its strength and thermal conductivity are appropriate, but the thickness is preferably 2 to 25 μm, for example.

The heat-fusible ink layer provided on the base film is composed of a colorant having an intermediate color and a binder, and may further contain various additives if necessary. This intermediate colorant is a colorant having a hue other than black, yellow, magenta and cyan, and an intermediate color of an arbitrary hue is developed by mixing at least two kinds of colorants of the above three primary colors. A colorant having a unique hue other than the three primary colors may be used alone. For example, red, green, purple, pink, etc. are typical, and a hue in between may be used. Further, in the present invention, a fluorescent color composed of a so-called fluorescent pigment or fluorescent dye, a metallic luster colorant such as gold or silver, and a white colorant may be contained. Coloring agents other than these three primary colors may be obtained by toning by themselves, or may be easily obtained from the market and used. The amount of these colorants used is generally preferably about 5 to 70% by weight in the ink layer.

Wax is mainly used as the binder, but other drying oils, resins, mineral oils, cellulose and rubber derivatives and the like can be used together. Typical examples of the wax used as the binder include microcrystalline wax, carnauba wax and paraffin wax. Furthermore, Fischer-Tropsch wax,
Various waxes such as low molecular weight polyethylene, wood wax, beeswax, spermaceti wax, ivowa wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, partially modified wax, fatty acid ester and fatty acid amide can be mentioned. In the present invention, a thermoplastic resin having a relatively low melting point can be further mixed in the wax to improve the adhesion of the ink to the transfer material.

Examples of the method for forming the hot melt ink layer on the base film include hot melt coating, hot lacquer coating, gravure coating, gravure reverse coating, roll coating and many other means. The thickness of these ink layers may be several μm as in the conventional case. As the material B to be transferred, ordinary high-quality paper, plain paper, synthetic paper, tracing paper, plastic film, etc.
Any heat transferable sheet or film may be used as long as it is used as a conventional material to be transferred for heat transfer. Further, the size of these transfer materials may be sheets such as A plate and B plate, but is preferably a continuous sheet having an arbitrary width.

The adhesive used in the construction of the adhesive layer C for temporarily adhering the thermal transfer sheet A and the transfer material B to each other is any known adhesive as long as the ink layer does not transfer to the transfer material B when they are peeled off. An adhesive (adhesive) can also be used. One example of a preferable adhesive is composed of an adhesive resin (or particles thereof) having a low glass transition temperature and a wax. The glass transition temperature of the adhesive resin is preferably in the range of -90 ° C to -60 ° C, and examples of such an adhesive resin include a rubber-based adhesive resin, an acrylic-based adhesive resin and a silicone-based adhesive resin. Adhesive resin of, and, depending on the form, solvent solution type, aqueous solution type, hot melt type, aqueous or oily emulsion type, any of which can be used in the present invention, but particularly preferable in the present invention Is an acrylic aqueous emulsion type. When the above-mentioned adhesive resin is used alone, excellent adhesiveness is obtained, but the releasability of the transferred material is insufficient and non-uniform, and it may occur unexpectedly before thermal transfer such as during production, storage and transportation. When a force is applied, the ink layer of the thermal transfer sheet may be transferred to the material to be transferred to cause scumming. Further, during thermal transfer, foil breakage of the ink layer is inferior, and for example, the ink layer may be transferred to the periphery of the heat application area by the thermal head, resulting in poor resolution of the transferred image.

In the present invention, the above-mentioned problem can be solved by adding an emulsion of the wax used for forming the ink layer to the above-mentioned emulsion adhesive resin, whereby the adhesiveness can be adjusted to a preferable range, and the above-mentioned problem of scumming occurs. It was found that the above problem was solved, the foil breakage of the adhesive layer C was improved, and the resolution of the transferred image was significantly improved. The weight ratio of the adhesive resin to the wax is preferably 1: 0.5 to 1: 4,
Outside of this range, the above-mentioned various problems are likely to occur, which is not preferable. It is also possible to easily adjust the tackiness to a preferable range by adding a resin emulsion having a higher glass transition temperature to the emulsion of the tacky resin. As such a resin emulsion, for example, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, polyethylene, polystyrene,
Thermoplastic resins such as polypropylene, polybutene, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, acrylic resin and the like, and acrylic emulsion are particularly preferable. Such a resin preferably has a glass transition temperature higher than that of the adhesive resin, for example, a glass transition temperature of 60 ° C. or higher, and may be a thermosetting resin in some cases.
When using resin particles having a high glass transition temperature,
The weight ratio of the adhesive, the resin particles and the wax is 3 to 5:
It is preferably 1 to 2.5: 3 to 5. The adhesive force (g) of the adhesive layer formed as described above is 25 mm (width)
Cut a sample of x55 mm (length) and use a surface friction measuring device (HEIDON-14, manufactured by Shinto Kagaku) to measure 1800 mm / m
in. 800-2000 when measured at a pulling speed of
A range of g is preferred.

When the adhesive force is less than the above range, the adhesive force between the thermal transfer sheet and the material to be transferred is too low, the two are easily separated, and the thermal transfer sheet is more likely to be wrinkled. When the adhesive force exceeds the above range, the adhesive force is sufficient, but the ink layer is easily transferred to the transfer material even in the non-printed portion, and the transfer material is contaminated. However, when the amount of the thermoplastic resin in the ink layer is, for example, an ethylene-vinyl acetate copolymer having a vinyl acetate content of 28%, and the solid content in the ink layer is 9% by weight or more, a base film is obtained. Since the adhesiveness with the ink layer is increased to that extent, it is possible to obtain a thermal transfer sheet that does not cause contamination of the transfer material even if the adhesive force of the adhesive layer to the transfer material is in the range of 1300 to 2000 g. The adhesive layer C composed of the above components may be provided on the surface of the material B to be transferred, but in this case, since the printed matter remains tacky, it is preferably provided on the surface of the ink layer 2 of the thermal transfer sheet. In this case, since the adhesive is used as an aqueous emulsion, it is preferable because it does not damage the ink layer. The coating method and the drying method of the emulsion are not particularly limited, but the drying is preferably performed at a low temperature so that the particles of the emulsion remain. The adhesive layer has a thickness of 0.1 to 20 μm.
A thickness of (as a solid coating amount of 0.1 to 5 g / m ² ) is preferable.

Adhesion between the thermal transfer sheet A and the transfer material B is
Preferably, it is carried out by continuously adhering the material to be transferred while forming an adhesive layer on the surface of the ink layer of the thermal transfer sheet, and winding it up in a roll shape. However, the thermal transfer sheet may be placed outside,
Further, these may be cut into sheets. The above is the basic structure of the co-rolling thermal transfer sheet of the present invention. Of course, as shown in FIG. 1, a slip layer 4 for preventing sticking of the thermal head and improving slipperiness may be provided on the back surface of the thermal transfer sheet, Any of the techniques well known in the thermal transfer sheet field, such as providing a peeling layer 3 between the base film and the ink layer to improve the peeling of the ink layer and to provide a protective layer after printing, can be applied to the thermal transfer sheet of the present invention. Can be added. The above-mentioned thermal transfer sheet of the present invention is set on, for example, a facsimile printer, conveyed as indicated by an arrow in FIG. Image 6 is formed.

[0015]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, “part” or “%” is based on weight unless otherwise specified. Example 1 A 6.0 μm-thick polyethylene terephthalate film having a slip layer provided on the back surface was used as a base film, and one of the surfaces was coated with the following ink composition at a rate of 3 g / m ^2. , And an ink layer was formed. Ink composition : Intermediate colorant (cyanine green 2GN) 10 parts Ethylene / vinyl acetate copolymer 14 parts Paraffin wax 60 parts α-Olefin-maleic anhydride copolymer 7 parts Oxide wax 15 parts (at 120 ° C. with an attritor) Kneading for 4 hours) Further, a temporary adhesive having the following composition was applied onto the above ink layer by a gravure coating method at a coating amount of 0.5 g / m ² at the time of drying. Amount 64 g / m ² , Beck surface smoothness 3
50 sec. ) And a nip temperature of 50 ° C. and a nip pressure of 5 Kg / cm ² to obtain a thermal transfer sheet of the present invention. Temporary adhesive composition Acrylic adhesive resin dispersion (solid content 40%, Tg = -58 ° C) 10 parts Carnauba wax aqueous dispersion (solid content 40%, melting point 83 ° C) 20 parts Water 10 parts Isopropanol 20 parts

Examples 2 to 3 The thermal transfer sheet of the present invention was obtained in the same manner as in Example 1 except that the colorant in Example 1 was changed as follows. Example 2: 10 parts of neutral colorant (Red 5R 745S) Example 3: Intermediate colorant (Blu-CP-145S 4 parts + Violet B 2 parts) Example 4 Thickness 6 with slip layer provided on the back surface A film of polyethylene terephthalate having a thickness of 0.0 μm was used as a base film, and the ink composition described below was applied to one surface of the film at a rate of 6 g / m ² to form an ink layer. Ink composition : Fluorescent pigment (Epocolor FP315, orange) 80 parts Ethylene / vinyl acetate copolymer 5 parts Paraffin wax 60 parts α-Olefin-maleic anhydride copolymer 7 parts Oxidation wax 15 parts (at 120 ° C. with an attritor) Kneading for 4 hours) Further, a temporary adhesive having the following composition was applied onto the above ink layer by a gravure coating method at a coating amount of 0.5 g / m ² at the time of drying. Amount 64 g / m ² , Beck surface smoothness 3
50 sec. ) And a nip temperature of 40 ° C. and a nip pressure of 5 Kg / cm ² to obtain a thermal transfer sheet of the present invention. Temporary adhesive composition Acrylic adhesive particles Aqueous dispersion (solid content 40%, glass transition temperature −70 ° C., particle size 3 to 10 μm) 20 parts Acrylic resin particle aqueous dispersion (solid content 20%, glass transition temperature 85 ° C.) , Particle size 0.2 to 0.3 μm) 10 parts Carnauba wax aqueous dispersion (solid content 40%, melting point 83 ° C.) 10 parts Water 10 parts Isopropanol 30 parts

Examples 5 to 8 The thermal transfer sheet of the present invention was obtained in the same manner as in Example 1 except that the colorant in Example 4 was changed to the following colorant. Example 5: Fluorescent pigment (Epocolor FP1000N, pink) 60 parts Example 6: Fluorescent pigment (Epocolor FP1050, blue) 60 parts Example 7: Fluorescent pigment (Epocolor FP3000G, green) 60 parts Cyanine Green 1.5 parts Example 8 The thermal transfer sheet of the present invention was obtained in the same manner as in Example 1, except that the ink in Example 4 was changed to the following ink. Ink composition (gold color): Metal pigment (aluminum paste SAP574PS) 4 parts Seika First Yellow M 19 parts Ethylene / vinyl acetate copolymer 23 parts Carnauba wax 13 parts Paraffin wax 40 parts (kneaded at 120 ° C. for 4 hours with an attritor) Example 9 A thermal transfer sheet of the present invention was obtained in the same manner as in Example 1 except that the ink in Example 4 was changed to the following ink. Ink composition (silver color): Metal pigment (Altop 18T) 25 parts Ethylene / vinyl acetate copolymer 23 parts Carnauba wax 13 parts Paraffin wax 40 parts (prepared by kneading at 120 ° C. for 4 hours in an attritor) Example 10 The thermal transfer sheet of the present invention was obtained in the same manner as in Example 1 except that the ink in Example 4 was changed to the following ink. Ink composition (white): Titanium oxide 50 parts Ethylene / vinyl acetate copolymer 15 parts Carnauba wax 9 parts Paraffin wax 26 parts (prepared by kneading at 120 ° C for 4 hours in an attritor) A plain paper colored black was used as. ) The adhesive strength between the ink layer and the paper of the thermal transfer sheet of the above example was such that the paper did not easily peel off even when left alone, and easily peeled off with a fingertip after printing, and the paper was free from scumming. .. When printing was performed using the above-mentioned thermal transfer sheet, a beautiful image having a hue corresponding to each ink layer was formed.

[0018]

[Effects] According to the present invention as described above, by coloring the ink layer of the thermal transfer sheet with a colorant having a hue other than black and the three primary colors, a desired intermediate color image can be formed even with the co-rolled thermal transfer sheet. Is. Further, in a preferred embodiment, by forming the adhesive layer with an adhesive having a specific composition, the thermal transfer sheet and the paper are firmly adhered to each other, and wrinkles and deviations do not occur, and both are easy after thermal transfer. There is provided a thermal transfer sheet which is peeled off, and the ink layer is accurately transferred to the paper in the transfer area, and the non-transfer area is not transferred at all, and does not contaminate the paper.

[0019]

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating a cross section of a thermal transfer sheet of the present invention.

FIG. 2 is a diagram schematically illustrating a cross section of a thermal transfer sheet of the present invention.

[Explanation of symbols]

 A: Thermal transfer sheet B: Transfer material C: Adhesive layer 1: Substrate film 2: Ink layer 3: Release layer 4: Slip layer 5: Thermal head 6: Image

Claims (1)

Claim: What is claimed is: 1. A thermal transfer sheet comprising a substrate film and a thermal transfer sheet having a heat-fusible ink layer formed on one surface of the substrate film, and a transfer material, which are releasably bonded by an adhesive layer. In the thermal transfer sheet, the ink layer is colored with a colorant having a hue other than black and the three primary colors.