JP2873915B2 - Thermal transfer sheet - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a heat-sensitive transfer sheet, and more particularly, to a heat-sensitive transfer sheet having a function of matte printing, antistatic, sticking prevention or security leakage prevention. . [0002] When a computer or word processor prints by a thermal transfer method, a thermal transfer sheet having a heat-meltable ink layer provided on one surface of a base film is used. Conventional heat-sensitive transfer sheets use paper such as 10 to 20 μm thick condenser paper or paraffin paper, or 3 to 20 μm thick plastic film such as polyester or cellophane as a base film. This is manufactured by providing a hot-melt ink layer in which is mixed by coating. However, prints or images recorded by a thermal printer are generally glossy. Although glossy printing is beautiful, it is not preferable from the standpoint of legibility. Therefore, it is desired to perform matte printing. If paper is used instead of plastic as the base film, the glossiness of the print will be low, but it is still insufficient, and plastics, especially polyester, can be made thin (up to about 1.6μ) and have high strength. Therefore, it is becoming mainstream recently. From this,
The demand for matte printing is strong. Also, if the base film is made of plastic, the generation of static electricity is severe,
There are many problems in handling or printing quality such as clinging to hands or adsorbing dust, and it is necessary to perform antistatic treatment. In addition, since the ink in the portion printed by heating by the thermal head comes off, reading becomes possible, and there is a risk of leakage of confidential information. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art. In particular, the present invention makes it possible to read by heating a portion which has been heated and printed by a thermal head. And to prevent leakage of confidential information. [0004] In order to achieve the above object, the present invention provides a base film having a heat-fusible ink layer which is melted by the heat of a thermal head on one surface and the other surface thereof. A heat-sensitive transfer sheet having a layer for preventing sticking to a thermal head, wherein the anti-sticking layer contains a conductive powder and a heat releasing agent or a lubricant.
The hot-melt ink layer and the anti-sticking layer have the same color. [0005] By making the hot-melt ink layer and the anti-sticking layer the same color, the portion where the ink is removed by heating and printed and the portion where the ink is not removed have the same color. In this case, the printed content cannot be read, and the leakage of confidential information can be prevented. At the same time, the anti-sticking layer is
By containing conductive powder and thermal release agent or lubricant
Surface resistance is reduced, an antistatic effect can be exhibited, and
In addition, the releasability from the thermal head can be enhanced. Preferred embodiments include conventional polyester, polypropylene, cellophane, acetate,
Use plastic films such as polycarbonate and papers such as condenser paper and paraffin paper. A polyester film is optimal. [0007] The hot-melt ink is prepared by blending a colorant with EVA, paraffin wax, carnauba wax and the like. As the coloring agent, in addition to the coloring agents forming cyan, magenta, yellow, and black, coloring agents of various other colors can also be used. That is, the heat-meltable ink is selected and added as a colorant according to the color to be provided with carbon black or various dyes and pigments. The coating amount of the hot-melt ink is suitably 3 to 5 μm in order to stably perform high-quality printing. [0008] The mat layer which characterizes the present invention must have the following characteristics. (1) Having heat resistance When the mat layer is softened or melted by the heat of the thermal head, heat energy is lost first, causing a decrease in sensitivity, and second, peeling between the base film and the mat layer occurs. When the mat layer adheres to the ink surface, the matting effect is reduced, and thirdly, the degree of adhesion between the mat layer and the hot-melt ink layer changes, and when the mat layer has tackiness, There is a problem that uneven transfer occurs due to the remaining ribbon of ink. (2) It must have good thermal releasability It is necessary for the mat layer and the hot-melt ink layer to have good releasability when heated. (3) A thin film preferably has a thickness of 0.2 to 3 μm. In order to ensure a preferable average mat depth of 0.15 to 2 μ, a thickness of 0.2 μ or more is required. If it exceeds 3 μm, the thermal sensitivity becomes low. In order to obtain the above characteristics, the mat layer is made of the following materials. A) A synthetic resin having a resin glass transition point of 60 ° C. or more is suitable.
Representative examples are acrylic resins, polyester resins, phenolic resins, fluororesins, polyimide resins, methyl methacrylate resins, vinylidene fluoride resins, vinylidene fluoride-atrafluoroethylene copolymer resins, polyvinyl fluoride resins, acrylonitrile-styrene And copolymer resins. A resin obtained by adding a compound having two or more amino groups or a diisocyanate or triisocyanate to a thermoplastic resin having an OH group or a COOH group is also preferable. Thermoplastic resins having OH or COOH groups include polyester resins, vinyl chloride / vinyl acetate copolymers, polyether resins, polybutadiene resins, acrylic polyols, urethane or epoxy prepolymers having OH groups, nitrocellulose resins, and cellulose. It is preferable to use an acetate propionate resin, a cellulose acetate butyrate resin, or a cellulose acetate resin. These resins may have an OH group or a COOH group in the polymerized unit, or may have an OH group or a COOH group at a terminal or a side chain. Examples of the diisocyanate to be added to the above-mentioned thermoplastic resin having an OH group or a COOH group include paraphenylene diisocyanate, 1-chloro-2,4-phenyl diisocyanate, 2-chloro-1,4-phenyl diisocyanate, 4-toluene diisocyanate,
2,6-toluene diisocyanate, 1,5-naphthalenediisocyanate, hexamethylene diisocyanate and 4,4'-biphenylene diisocyanate; examples of triisocyanates are triphenylmethane triisocyanate and 4,4 ', 4'-trimethyl-
3,3 ', 2'-triisocyanate-2,4,6-triphenylcyanurate. Examples of the compound having two or more amino groups include melamine, methylated melamine, methylated methylolmelamine, butylated melamine,
Butylated methylolmelamine, dicyandiamide, guanidine, biguanide, diaminomelamine, guanylmelamine, urea, biuret, ammeline, ammelide, butylated urea and methylated urea, and guanamines such as formoguanamine, acetoguanamine, benzoguanamine, phenylacetoguanamine , Methoxyguanamine and N-methylolacrylamide copolymer polymers can also be used. When a compound having two or more of the above amino groups is used, the curing catalyst may be ammonium phosphate, triethanolamine, acetamide, urea, pyridine, paratoluenesulfonic acid, sulfanilic acid, guanidine stearate, guanidine carbonate. Use such as. The diisocyanate, triisocyanate and amino compound may be used alone or in combination of two or more to form a thermoplastic resin 10 having an OH group or a COOH group.
5 to 40 parts by weight, preferably 10 to 2 parts by weight, per 0 parts by weight
0 parts by weight are added. These act as crosslinking agents to cure the mat layer appropriately and increase the adhesion of the mat layer to the plastic film. B) A substance which enhances the releasability between the mat layer and the hot-melt ink layer when a thermal release agent or a lubricant is heated, a substance which melts by heating to exhibit this property, and a substance which works as a solid powder. There are things. Those belonging to the former group are waxes such as polyethylene wax and paraffin wax, amides, esters and salts of higher fatty acids, and phosphate esters such as higher alcohols and lecithin. The latter group includes fluoroplastics such as Teflon and polyvinyl fluoride, guanamine resins, boron nitride, silica, wood flour, talc and the like. Of course, two groups may be used together. The amount used is such that the above-mentioned heat releasing agent or lubricant occupies 10 to 50% by weight in the mat layer. C) Matting agent An appropriate amount of the following inorganic pigments is used. Silica, talc, calcium carbonate, precipitated barium sulfate, alumina,
Acid clay, clay, magnesium carbonate, carbon black, tin oxide, titanium white, etc. Some of them overlap with the above-mentioned heat releasing agents or lubricants, and they also have the functions of B) and C). The formation of the mat layer on the base film is carried out by dissolving or dispersing the above constituent materials in an appropriate solvent, adjusting the viscosity to be suitable for coating, and applying the composition to the base film using a conventional coating means. Performed by Next, the anti-sticking layer, which is a feature of the present invention, is a layer for preventing sticking between the base film and the thermal head. The basic components are the resin and the heat releasing agent or lubricant used for forming the mat layer described above and the following materials. A) conductive powder nickel, iron, copper, silver, aluminum, gold, cadmium, cobalt, chromium, magnesium, molybdenum,
Metal powders of lead, palladium, platinum, rhodium, tin, tantalum, titanium, tungsten, zinc, zirconium, etc. or oxides of these metal powders or carbon black,
Conductive carbon such as graphite is used. A) Colorants In addition to the colorants that form cyan, magenta, yellow, and black, other various colorants can also be used. That is, the anti-sticking layer serves as a coloring agent.
Carbon black or various dyes and pigments are selected and added so as to have the same color as the hot-melt ink layer according to the color to be applied to the anti-sticking layer. The anti-sticking layer on the base film is formed by dissolving or dispersing the above constituent materials in an appropriate solvent, adjusting the viscosity to a level suitable for coating, and applying the composition to the base film by using a conventional coating means. It does by doing. The thermal transfer sheet of the present invention can include various modifications. One example is to provide a primer layer on the base film to increase the adhesive strength with the mat layer. The primer layer can be easily formed by applying a known primer coating. For example, it is preferable to use a combination of an acrylic resin, a polyester resin, a polyvinyl acetate resin, a vinyl chloride / vinyl acetate resin, a polyol and a diisocyanate, a polyol and a melamine, or a combination of an epoxy resin and a diisocyanate as a binder. When the base film is made of polyester, the primer paint has a remarkable improvement in adhesive strength. Example (Anti-sticking layer 1) 8 parts by weight of acrylonitrile-styrene copolymer resin (Sebian N, manufactured by Daicel Chemical) 32 parts by weight of acrylic polyol (manufactured by Denka Polymer, 50% solution of TP-5000, solvent) Is ethyl acetate, toluene, and MEK) Teflon powder 3 parts by weight (manufactured by Daikin Industries, Lubron L) Polyethylene wax 3 parts by weight (manufactured by Adeka Argus, Mark FC-113) 15 parts by weight of conductive carbon (manufactured by Lion Akzo, Ketjen (Black) Methyl ethyl ketone 40 parts by weight Toluene 40 parts by weight (Sticking prevention layer 2) 8 parts by weight of acrylonitrile-styrene copolymer resin (manufactured by Daicel Chemical, Sebian N) 32 parts by weight of acrylic polyol (manufactured by Denka Polymer, TP-) 5000 50% solution, solvents are ethyl acetate, toluene, and MEK) Teflon powder 3 parts by weight (manufactured by Daikin Industries, Lubron L) Polyethylene wax 3 parts by weight (Adeka Argus, Mark FC-113) Tin oxide 10 parts by weight (Mitsubishi Metal “T-1”) Yellow pigment 5 parts by weight (Dainichi Seika 2400) Methyl ethyl ketone 40 parts by weight Toluene 40 parts by weight (Primer layer ink) Polyester resin 3 parts by weight (Toyobo “Vylon 200”) Vinyl chloride / acetic acid Vinyl copolymer resin 3 parts by weight (UCIN "Vinylite VAGH") toluene 20 parts by weight methyl ethyl ketone 20 parts by weight Based on the above primer ink composition, 46% isocyanate (Takeda Pharmaceutical "Takenate D-110N") was added to 46:
The mixture was mixed at a ratio of 1 to obtain a primer layer ink. (Mat layer ink) Cellulose acetate propionate resin 10 parts by weight (Kodak “CAP504-02”) Butylated melamine 1.5 parts by weight (Nippon Reichhold “Super Betcamine J-820”) Calcium carbonate 2 parts by weight Part Teflon powder 1 part by weight (Daikin Industries "Rubron L") methyl cellosolve 15 parts by weight butyl acetate 20 parts by weight methyl ethyl ketone 20 parts by weight Based on the above composition, 40% of paratoluenesulfonic acid
A mixture of the isopropanol solutions at a ratio of 100: 1 was used as a mat layer ink. (Heat-fusible ink 1) Paraffin wax 10 parts by weight Carnauba wax 10 parts by weight Ethylene / vinyl acetate copolymer 1 part by weight (Sumitomo Chemical “Smitate HC-10”) Carbon black 2 parts by weight (Tokai electrode “SEIST” SO ”) The above composition was heated at 100 ° C. × 6 using a blade kneader.
What was kneaded for a time was designated as hot-melt ink 1. (Hot-meltable ink 2) The carbon black of the hot-melt ink 1 was converted to a yellow pigment (Dainichi Seika 240
0) Changed to 2 parts by weight. The above composition was kneaded at 100 ° C. for 6 hours using a blade kneader to obtain a hot-melt ink 2. Example 1 An isocyanate (Takenate D-204, 50% butyrate vinegar solution, manufactured by Takeda Pharmaceutical Co., Ltd.) was added to the above anti-sticking layer 1, and the anti-sticking layer 1: isocyanate = 12: 3 (weight ratio). The mixture was added and mixed at a ratio immediately before application by gravure printing to obtain a coating amount of 1 g /
so as to be m ^2, was coated on one surface of a polyester film having a thickness of 6 [mu (Toray), was sticking prevention layer is dried at a temperature 100 ° C.. Next, the primer layer ink and the mat layer ink are applied in this order on the surface of the 6 μ polyester film opposite to the anti-sticking layer in the following amounts by a gravure printing method to form a primer layer and a mat layer. did. Primer layer ink 0.5 g / m ² Matt layer ink 1 g / m ² On the mat layer, the hot-melt ink 1 was coated with 10 g
By a hot melt method heated to 0 ° C., a roll coating method was applied to a thickness of 5 μm to form a thermal transfer ink layer. Example 2 An isocyanate (Takenate D-204, 50% butyrate vinegar solution, manufactured by Takeda Pharmaceutical Co., Ltd.) was added to the above-mentioned anti-sticking layer 2, and the anti-sticking layer 2: isocyanate = 12: 3 (weight ratio). The mixture was added and mixed at a ratio immediately before application by gravure printing to obtain a coating amount of 1 g /
so as to be m ^2, was coated on one surface of a polyester film having a thickness of 6 [mu (Toray), was sticking prevention layer is dried at a temperature 100 ° C.. Next, the primer layer ink and the mat layer ink are applied in this order on the surface of the 6 μ polyester film opposite to the anti-sticking layer in the following amounts by a gravure printing method to form a primer layer and a mat layer. did. Primer layer ink 0.5 g / m ² Matt layer ink 1 g / m ² On the mat layer, the hot-melt ink 2 was coated with 10 g
By a hot melt method heated to 0 ° C., a roll coating method was applied to a thickness of 5 μm to form a thermal transfer ink layer. COMPARATIVE EXAMPLE 1 A heat-sensitive transfer sheet according to Example 1, except that the conductive carbon of the anti-sticking layer 1 was removed. Comparative Example 2 A heat-sensitive transfer sheet according to Example 2, wherein the anti-sticking layer of Example 1 was prepared by removing the conductive carbon. The heat-sensitive transfer sheets of Examples 1 and 2 and Comparative Examples 1 and 2 were slit into ribbons and printed by a commercially available printer. High quality paper to be transferred (Mitsubishi Paper "Tokuhishi" 46/72
Kg) Thermal head Thin film thermal head Printing energy 1 mJ / dot (4 × 10 ^-4 c
m ² ) Next, the effects of matte printing, antistatic, and confidential leakage prevention by the thermal transfer sheet of the present invention are shown below.
(Table 1) In general, the matting required for printing depends on the glossiness of the recording paper and the reading conditions. However, if the glossiness measured by a gloss meter is approximately 30 or less, it is always a sufficient level. It can be said that there is. With the present invention, this can be easily achieved. In Table 1, when the glossiness was 30 or less, the result was ○, and when it was 30 or more, the result was ×. The antistatic effect is
If less surface resistance 10 ⁹ Omega after hot-melt ink coated ○, it was × if more than 10 ⁹ Omega. Regarding the effect of preventing leakage of confidential information, the ribbon after printing was observed and the portion from which the hot-melt ink was removed was readable, and x was impossible. [Table 1] The gloss was measured for the gloss of the printed portion using a gloss meter (Murakami Color Shaping Laboratory "GM-3M") at a measurement angle of 60 °. The surface resistance is measured by a super insulation resistance meter YHP4329.
A-16008A. Examples 1 and 2,
Comparative Examples 1 and 2 did not cause sticking, and were printed well. The heat-sensitive transfer sheet of the present invention has the above-mentioned constitution. If this sheet is used, the heat-sensitive transfer sheet having a function of preventing confidential leakage and a function of matte printing, sticking prevention and antistatic can be obtained. Can do it.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Shigeki Kaise               2-20-1 Akabane Minami, Kita-ku, Tokyo (72) Inventor Tetsuro Irita               1-40 Kotake-cho, Nerima-ku, Tokyo (72) Inventor Kyoichi Yamamoto               7-29-5 Sagamidai, Sagamihara City (72) Inventor Kyohei Takahashi               4-11 Minamidai, Sagamihara-shi Tsurugaoka housing complex 2-               112                (56) References JP-A-59-138493 (JP, A)                 JP-A-58-153684 (JP, A)                 JP-A-59-98898 (JP, A)                 JP-A-57-120497 (JP, A)

Claims (1)

(57) [Claims] In a heat-sensitive transfer sheet having a heat-fusible ink layer that is melted by the heat of a thermal head on one surface of a base film and a layer that prevents sticking to the thermal head on the other surface, the sticking prevention A heat-sensitive transfer sheet characterized in that the layer contains a conductive powder and a heat releasing agent or a lubricant, and the hot-melt ink layer and the anti-sticking layer have the same color. 2. The heat-sensitive transfer sheet according to claim 1, wherein a mat layer is provided between the base film and the heat-meltable ink layer. 3. 3. The heat-sensitive transfer sheet according to claim 2, wherein a mat layer is provided after a primer layer is applied to the base film to increase an adhesive force between the base film and the mat layer.