JP2991375B2 - Thermal transfer sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a thermal transfer sheet, and more particularly, to a thermal transfer sheet capable of printing and forming an image in a fluorescent color.

(Conventional technology and its problems) Conventionally, when printing an output print of a computer or a word processor by a thermal transfer method, a thermal transfer sheet provided with a heat-fusible ink layer on one surface of a base film is used. .

This conventional thermal transfer sheet has a thickness
Using a 10-20 μm thick paper such as condenser paper or paraffin paper or a 3 to 20 μm thick plastic film such as polyester or cellophane, a hot-melt ink layer in which a coloring agent such as a pigment or a dye is mixed with wax is used. It is manufactured by coating.

Thermal transfer sheets of black, yellow, magenta and cyan are known as these thermal transfer sheets, and thermal transfer sheets of a fluorescent color containing a fluorescent dye as a special color are also known.

As described above, when a thermal transfer sheet is manufactured, a thin film having a thickness of several μm is used as a base film. As a result, static electricity problems occur during processing of the base film, application of ink, drying, and winding of the product. As a result, a defective product may be generated, and even during use, static electricity is generated due to friction with the paper at the time of rewinding and winding up the thermal transfer sheet, and furthermore, at the time of thermal transfer, causing various inconveniences.

The antistatic treatment for solving the above problems is performed by forming a conductive layer containing conductive carbon black on any surface of the thermal transfer sheet. When this method is applied to a thermal transfer sheet of fluorescent color, Although there is no particular problem in the print quality itself, a major problem occurs in the appearance of the thermal transfer sheet itself.

That is, when a black conductive layer is formed on the back surface of the obtained fluorescent color heat transfer sheet, the black color is strongly appealed, and the fluorescent color is significantly contaminated in appearance. In the case of a fluorescent color heat transfer sheet, since it is often used for a handy type printer having a strong taste, the appearance contamination of the fluorescent color as described above significantly reduces the commercial value of the thermal transfer sheet itself. .

Accordingly, an object of the present invention is to provide a fluorescent color heat transfer sheet having excellent antistatic properties and high commercial value.

(Means for Solving the Problems) The above object is achieved by the present invention described below. That is, the present invention is a thermal transfer sheet in which a hot-melt ink layer containing a fluorescent pigment obtained by dissolving, curing and pulverizing a fluorescent dye in a thermosetting resin is formed on one surface of a base film, A thermal transfer sheet characterized in that a substantially colorless independent antistatic agent layer is provided on any surface or interface, and the overall surface resistance is about 10 ^{5 to} 10 ¹¹ Ωm.

(Function) By providing a substantially colorless independent antistatic agent layer on any surface or interface of the fluorescent color thermal transfer sheet, it is possible to provide a fluorescent color thermal transfer sheet having excellent antistatic properties and high commercial value. it can.

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to preferred embodiments.

The heat transfer sheet of the present invention, on one side of the base film,
A feature is that a hot-melt ink layer containing a fluorescent pigment is formed, and a substantially colorless independent antistatic layer is further provided on any surface or interface.

As the substrate film used in the present invention, the same substrate film as used in the conventional thermal transfer sheet can be used as it is, and other materials can be used, and there is no particular limitation. Specific examples of preferred base film include, for example, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber, ionomer, etc. Paper, such as plastic, condenser paper and paraffin paper, and non-woven fabric, and a base film obtained by combining these.

The thickness of the base film can be appropriately changed depending on the material so that the strength and the thermal conductivity are appropriate, but the thickness is preferably, for example, 2 to 25 μm.
It is.

The heat-meltable ink layer formed on the base film is
It may consist of a fluorescent pigment and a vehicle, and may further contain various additives as needed.

Various fluorescent pigments are known, such as a fluorescent pigment obtained by dissolving a known fluorescent dye in a thermosetting resin and curing it, and pulverizing the same to an appropriate particle size.
3000 (fluorescent yellow), Epocolor FP20 (fluorescent pink), Epocolor FP115 (fluorescent orange), Epocolor F
P1007 (fluorescent green), Shinloygi color FA48 (fluorescent blue), Fire Orange AX-14-5, glow red powder and the like are commercially available and can be used in the present invention. The amount of these fluorescent pigments used is about 2 in the ink.
A use proportion occupying 乃至 90% by weight is generally preferred.

As the vehicle, a mixture of wax as a main component, and other components such as a wax and a derivative of a drying oil, a resin, a mineral oil, cellulose, and rubber is used.

Representative examples of the wax include microcrystalline wax, carnauba wax, and paraffin wax. Further, various types of Fischer-Tropsch wax, various low molecular weight polyethylenes, wood wax, beeswax, spermaceti, Ibota wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, partially modified wax, fatty acid ester, fatty acid amide, etc. Wax is used.

In the present invention, the wax may be mixed with a thermoplastic resin having a relatively low melting point to improve the adhesion of the formed ink layer to the material to be transferred. Examples of such a thermoplastic resin include ethylene-vinyl acetate copolymer (EVA), ethylene-acrylate copolymer (EEA), polyethylene, polystyrene, polypropylene, polybutene, petroleum resin, vinyl chloride resin, and chloride resin. Vinyl-vinyl acetate copolymer, polyvinyl alcohol, vinylidene chloride resin, methacrylic resin, polyamide, polycarbonate, fluororesin, polyvinyl formal,
Polyvinyl butyral, acetylcellulose, nitrocellulose, polyvinyl acetate, polyisobutylene, ethylcellulose, polyurethane or polyacetal are used, and in particular, a relatively low softening point conventionally used as a heat-sensitive adhesive, for example, 20 to 80 ° C., preferably Is 50 ~ 80 ℃
Are preferred. The use ratio of the wax to the thermoplastic resin is preferably in the range of 5 to 300 in weight ratio of the thermoplastic resin to 100 of the wax.

For forming the ink layer, a method of melt-liquefying a mixture containing the above components and applying the same, or a method of dissolving and dispersing the above components in an appropriate solvent to form an ink, and applying and drying the ink can be used. Examples of the coating method include hot melt coating, hot lacquer coating, gravure coating, gravure reverse coating, roll coating, and many other means. It is preferable to use a solvent-type ink to form an ink layer because the hot-melt coat has low coatability and may cause thermal degradation of the fluorescent pigment because the fluorescent pigment has insufficient heat resistance.

In the present invention, a surface layer may be formed on the ink layer. This surface layer forms a part of the transfer film at the time of thermal transfer, and is formed mainly of wax as described above.

The surface layer may be formed by hot melt coating or the like in the same manner as the ink layer, but a preferred method is to use an aqueous dispersion containing wax. A particularly preferred method is to apply a water dispersion of wax on the hot melt ink layer and dry it at a temperature equal to or lower than the melting point of the wax. By doing so, the surface layer is formed while maintaining the particle shape of the wax.

The aqueous medium containing the wax is water or a mixture of water and a water-soluble organic solvent, for example, methanol, ethanol, and isopropanol.
By using 5 to 200 parts by weight per 100 parts by weight, the wettability of the aqueous wax dispersion with the hot-melt ink is improved.

Further, the wax aqueous dispersion may contain a small amount of an emulsifier (surfactant) or a known additive such as a leveling agent. The solids content of this dispersion is of the order of 10 to 50% by weight.

In the present invention, the above-mentioned thermoplastic resin having a relatively low melting point can be mixed with the dispersion to improve the adhesion of the surface layer formed to the material to be transferred. The use ratio of the wax to the thermoplastic resin is preferably in the range of 5 to 300 in weight ratio of the thermoplastic resin to 100 of the wax.

The surface layer formed from the wax is formed by applying an ink composition containing a wax by a conventionally known coating method, and drying.If the drying is performed at a temperature equal to or higher than the melting point of the wax, A smooth surface layer is formed,
On the other hand, when the dispersion is dried at a temperature lower than the melting point of the wax, a surface layer having a fine irregular surface with the particle shape of the dispersion remaining is formed.

In the present invention, the surface layer formed as described above has a thickness of preferably 0.1 μm or more and less than 5 μm so that the sensitivity is not insufficient even when the printing energy is low as in a high-speed type printer. . This thickness is 0.1
If it is less than μm, the paper to be transferred and the ink layer may be rubbed to cause background contamination. The surface layer is substantially colorless after thermal transfer, and may be colored white by adding an appropriate amount of extender or white pigment.

When a heat-sensitive material is used for the base film, it is preferable to provide a layer for preventing sticking of the thermal head on the surface in contact with the thermal head. The sticking prevention layer has a heat-resistant resin and a substance acting as a heat release agent or a lubricant as basic constituent components. As the heat-resistant resin, a compound having two or more amino groups or a diisocyanate or a triisocyanate is added to a synthetic resin having a glass transition point of 60 ° C. or higher or a thermoplastic resin having an OH group or a COOH group, and the resin is slightly cross-linked and cured. Are preferred. Thermal release agents or lubricants that act by melting when heated, such as amides, esters and salts of waxes and higher fatty acids, and those that remain solid, such as powders of fluororesins and inorganic substances There is.

By providing such an anti-sticking layer, thermal printing can be performed without sticking even on a thermal transfer sheet based on a heat-sensitive plastic film. Advantages such as ease can be used.

A thermal transfer image generally has a glossy print and is beautiful, but on the other hand, matte printing may be desirable because the document may be difficult to read. In such a case, for example, as proposed by the applicant (Japanese Patent Application No. 58-208306), a substrate film is coated with an inorganic pigment such as silica or calcium carbonate dispersed in an appropriate solvent. It is preferable to form a thermal transfer sheet by providing a mat layer and then coating a hot-melt ink layer. Alternatively, the base film itself may be used after being subjected to mat processing (the technique of Japanese Patent Application No. 58-208307 also proposed by the applicant).

The fluorescent color heat transfer sheet of the present invention is characterized in that an independent antistatic agent layer is formed on any surface or interface of the fluorescent color heat transfer sheet having the above-described configuration. The antistatic agent used in the present invention is substantially colorless unlike conventional conductive carbon. Many such substantially colorless antistatic agents have hitherto been known, and include Statiside (Analytical Chemical Laboratories), Unidyne (Daikin Industries), TB (Matsumoto Yushi Seiyaku), Chemistat (Sanyo Chemical), and Denone (Marubishi Oil). ), Electro stripper (Kao), lipomin, XD, AMS (lion),
ARQUAD, ESOMIN, ESOJOMIN, ESOQUAD, DUOMAC, PROPOQUAD, PROPOMIN (LION ARMOR), ELEGAN, NEW ELEGAN (Nippon Yushi), NEOGEN, AMOGENE, ELELON, REGISTERED (Daiichi Kogyo), AS, XG (Owaki Chemical) ), Elecles (Souwa Chemical), Gafstat (GAF), Catanac (ACC) and the like.

As a method of using the above-mentioned antistatic agent, there is a method of preparing a solution having an appropriate concentration and applying the solution to at least one surface of a base film before forming an ink layer. Many problems in the manufacture of sheets are solved. Further, an independent antistatic agent layer may be formed by applying an antistatic agent to any surface of the obtained fluorescent color heat transfer sheet, and according to this method, the fluorescent color thermal transfer sheet may be charged by use of the heat transfer sheet. Can solve the problem. As still another method, an independent antistatic agent layer may be formed between the base film and the ink layer, the ink layer and the surface layer, or the base film and the anti-sticking layer as described above.

The amount of the antistatic agent used as described above varies depending on the type of the antistatic agent used and the region to be formed. In any case, the surface resistance of the entire fluorescent color heat transfer sheet is about 10 ^5.
To 10 ¹¹ Ωm, specifically, in terms of solid content.
The range is preferably from 0.001 to 10 g / m ² .

The fluorescent color thermal transfer sheet of the present invention as described above is particularly suitable for a handy type printer used for decorative purposes, but of course, other general thermal transfer printers, for example, any of a commercial line or a serial type It can also be applied to printers.

(Effect) According to the present invention as described above, by providing a substantially colorless independent antistatic agent layer on any surface or interface of the fluorescent color heat transfer sheet, the antistatic property is excellent and the commercial value is high. A fluorescent color heat transfer sheet can be provided.

(Examples) Hereinafter, the present invention will be described more specifically with reference to examples. In the description, parts and% are based on weight unless otherwise specified.

Example 1 A polyethylene terephthalate film having a thickness of 3.5 μm was used as a base film, and a 0.5% isopropyl alcohol solution of an antistatic agent (trade name: Statiside, manufactured by Analytical Chemical Laboratories) was used on one surface of the base film.
Coating and drying were performed at a rate of 0.01 g / m ² to form an independent antistatic layer. Next, a hot-melt ink having the following composition and a surface layer material were applied and dried on the surface of the independent antistatic agent layer by the above-mentioned means to obtain a fluorescent color heat transfer sheet of the present invention.

Hot-melt ink layer Fluorescent yellow (Epocolor FP3000) 45 parts Ethylene / vinyl acetate copolymer (Evaflex 42
0, manufactured by Mitsui Polychemicals) 24 parts Paraffin wax (paraffin HNP-10, manufactured by Nippon Seisaku) 42 parts Carnauba wax 14 parts Xylol 153.8 parts Isopropyl alcohol 31 parts Gravure rolls that have been thoroughly dispersed using an attritor It was applied and dried at a rate of 5 g / m ² (dry state) by a coating method.

Surface layer 155F Paraffin wax emulsion (WE-75, manufactured by Bond Wax Co., 40% solids aqueous emulsion) 20 parts Ionomer resin (Chemipearl S-100, manufactured by Mitsui Petrochemical, solids 27%) 10 parts 60% isopropanol aqueous solution 15 Part The composition was applied to the surface of the ink layer at a rate of 0.8 g / m ² (dry state) by a gravure coating method, and dried at 60 ° C. to form a surface mat-like surface layer.

The above thermal transfer sheet shows a clear yellow fluorescent color appearance, using high quality paper as the paper to be transferred, and performing thermal transfer printing using a commercially available thermal head. did it.

Example 2 Using a 6 μm thick polyethylene terephthalate film as a base film, the present invention was carried out in the same manner as in Example 1 using a hot-melt ink layer having the following composition, an independent antistatic agent layer, and a surface employed ink. A thermal transfer sheet was obtained.

Hot-melt ink layer Fluorescent green pigment (Epocolor FP1007) 45 parts Ethylene / vinyl acetate copolymer (Smitate KC-10,
Sumitomo Chemical Co., Ltd.) 7.5 parts Oxidized paraffin ester compound (amide polymer T-820, made of electrified polymer) 12.5 parts Paraffin wax (paraffin SP-0145, made by Nippon Seisaku) 15 parts Maitarocrystalline wax (Himic 2065, Japan) 10 parts Isopropanol 5 parts Xylene 46 parts Independent antistatic agent layer Antistatic agent (staticide) 1.0 part Solvent Isopropyl alcohol 200 parts Surface layer Carnauba emulsion (WE-95, manufactured by Bondwax, solid content 40%) 30 parts Ethylene / vinyl acetate copolymer emulsion (Polysol EVAAD-5, manufactured by Showa Polymer, solid content 56%) 10 parts 75% isopropanol aqueous solution 60 parts This thermal transfer sheet also has a beautiful appearance as in Example 1. It showed good transfer performance.

Continuation of front page (56) References JP-A-63-5989 (JP, A) JP-A-51-82111 (JP, A) JP-A-61-228994 (JP, A) JP-A-51-82112 (JP, A) JP-A-62-55193 (JP, A) JP-A-64-16687 (JP, A)

Claims (1)

(57) [Claims] 1. A thermal transfer sheet having a heat-meltable ink layer containing a fluorescent pigment obtained by dissolving, curing and pulverizing a fluorescent dye in a thermosetting resin on one surface of a base film, A thermal transfer sheet having a substantially colorless independent antistatic agent layer provided on the surface or interface thereof, and having an overall surface resistance of about 10 ^{5 to} 10 ¹¹ Ωm.