JPH0582317B2 - - Google Patents

Description

[Detailed description of the invention]

OBJECT OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement in a thermal transfer sheet, and more particularly, to a thermal transfer sheet that provides functions of matte printing, prevention of static electricity, and prevention of secret leakage. [Prior Art] When printing a computer or word processor using a thermal transfer method, a thermal transfer sheet is used, which has a base film and a heat-melting ink layer on one side. Conventional thermal transfer sheets use a 10 to 20 micron thick paper such as capacitor paper or paraffin paper, or a 3 to 20 micron thick plastic film such as polyester or cellophane as a base film, and add pigment to the wax. This product is manufactured by coating a layer of hot-melt ink containing a mixture of the following. However, prints or images recorded with a thermal printer are generally glossy. Although glossy printing is beautiful, it is not desirable in terms of readability, so it is desired to perform matte printing. If paper is used instead of plastic as the base film, the gloss of the print will be lower, but it is still insufficient, and plastic, especially polyester, can be made thinner (up to about 1.6μ).
Due to its high strength, it has recently become mainstream. For this reason, there is a strong demand for matte printing. Furthermore, when the base film is made of plastic, there are many problems in terms of handling and printing quality, such as the generation of static electricity that sticks to hands or attracts dust, and therefore requires antistatic treatment. Furthermore, if the ink in the area heated and printed by the thermal head bleeds off, it becomes readable and there is a risk of leaking confidential information. [Problems to be Solved by the Invention] An object of the present invention is to improve the above-mentioned drawbacks of the conventional heat-sensitive transfer sheets and to provide a heat-sensitive transfer sheet that provides functions of matte printing, prevention of static electricity, and prevention of secret leakage. be. Structure of the Invention [Means for Solving the Problems] In the present invention, by incorporating conductive powder into the matte layer provided on the base film, and if necessary, changing the color of the matte layer. The above drawbacks of the prior art are solved by making the color the same as that of the hot-melt ink layer.The present invention provides a matte layer on the base film surface, and a matte layer on the matte layer. A heat-sensitive transfer sheet having a heat-melting ink layer that is peeled off from a matte layer, wherein the matte layer is made of the following components A, B, C A thermoplastic resin, or OH group, or COOH.
A resin obtained by adding a compound or diisocyanate having two or more amino groups to a thermoplastic resin having two or more amino groups, B a matting agent made of fine powder of an inorganic pigment, C a conductive powder, and the average matting depth of the matting layer is 0.15. ~
2 μ, and the surface resistance value of the mat layer is 10 ⁹ Ω.
This is a heat-sensitive transfer sheet characterized by the following. If it is necessary to prevent leakage of confidential information, the main idea is to make the color of the matte layer the same as the color of the heat-melting ink layer. As the base film, commonly used plastic films such as polyester, polypropylene, cellophane, acetate, and polycarbonate, and papers such as condenser paper and paraffin paper are used. Polyester film is most suitable. Hot-melt ink is prepared by blending a colorant with EVA, paraffin wax, carnauba wax, etc. Colorants include cyan, magenta,
In addition to colorants that form yellow and black,
Colorants of various other colors can also be used.
That is, to the hot-melt ink, carbon black or various dyes and pigments are added as a coloring agent, selected according to the color to be imparted to the ink. The appropriate amount of heat-melting ink to be applied is a thickness of 3 to 5 μm in order to stably perform high-quality printing. The mat layer that characterizes the present invention must have the following properties. [Concerning (5), as necessary] (1) It must be heat resistant...When the mat layer softens or melts due to the heat of the thermal head, the first is a loss of thermal energy, causing a decrease in sensitivity, and the second is a loss of thermal energy. In this case, peeling occurs between the base film and the matte layer, and the matte layer adheres to the ink surface, reducing the matting effect. Thirdly, the degree of adhesion between the matte layer and the hot-melt ink layer changes. However, when toughness occurs in the matte layer, there is a problem in that uneven transfer occurs due to ribbons of ink remaining. (2) Must have heat releasability...The matte layer and the heat-melt ink layer must have good releasability when heated. (3) Thin film...The preferred film thickness is 0.2 to 3μ. In order to ensure a preferable average mat depth of 0.15 to 2μ, a thickness of 0.2μ or more is necessary. 3μ
If the temperature exceeds , the thermal sensitivity will decrease. (4) It must have antistatic properties...If the base film is made of plastic, it is especially necessary to prevent the generation of static electricity. If the surface resistance is less than 10 ⁹ Ω,
In our experience, there are no problems with ribbons such as clinging or dust adhesion when handling the ribbon. (5) The color must be the same as the heat-fusible ink layer...This is an effective means when it is necessary to prevent leakage of confidential information. In order to obtain the above characteristics, the mat layer is composed of the following materials. A. Resin A synthetic resin with a glass transition point of 60°C or higher is suitable. Typical examples are acrylic resins, polyester resins, phenolic resins, fluororesins, polyimide resins, methyl methacrylate resins, vinylidene fluoride resins, vinylidene fluoride-tetrafluoroethylene copolymer resins, polyvinyl fluoride resins, and acrylonitrile. Styrene copolymer resin, etc. 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 suitable. Thermoplastic resins having OH groups 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 select from acetate propionate resin, cellulose acetate butyrate resin, and 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 the terminal or side chain. Examples of diisocyanates added to the above thermoplastic resins having OH or COOH groups include paraphenylene diisocyanate, 1-chloro-
2,4-phenyl diisocyanate, 2-chloro-1,4-phenyl diisocyanate, 2,
4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate and 4,4'-biphenylene diisocyanate; examples of triisocyanates are triphenylmethane triisocyanate and 4,4'-biphenylene diisocyanate.
4',4'-trimethyl-3,3',2'-triisocyanate-2,4,6-triphenyl cyanurate. Further, examples of compounds having two or more amino groups include melamine, methylated melamine,
Formoguanamine, which is methylated methylolmelamine, butylated melamine, butylated methylolmelamine, dicyandiamide, guanidine, biguanide, diaminomelamine, guanylmelamine, urea, biuret, ammeline, acimeride, butylated urea and methylated urea, and is a guanamine. , acetoguanamine, benzoguanamine, phenyl acetoguanamine, methoxyguanamine and N-methylolacrylamide copolymers can also be used. When using a compound having two or more of the above amino groups, use ammonium phosphate, triethanolamine, acetamide, urea, pyridine, p-toluenesulfonic acid, sulfanilic acid, guanidine stearate, guanidine carbonate, etc. as a curing catalyst. do. The diisocyanate, triasocyanate, and amino compound may be used alone or in combination of two or more in an amount of 5 to 40 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of the thermoplastic resin having an OH group or a COOH group. Added. These act as crosslinking agents, moderately curing the matte layer, and increasing the adhesion of the matte layer to the plastic film. B. Thermal release agent or lubricant There are two types of substances that enhance the releasability of the matte layer and the hot-melt ink layer during heating: those that exhibit this performance by melting upon heating, and those that function as solid powders. Those belonging to the former group include waxes such as polyethylene wax and paraffin wax, amides, esters, and salts of higher fatty acids, higher alcohols, and phosphoric acid esters such as lecithin. The latter group includes Teflon, fluorocarbon resins such as polyvinyl fluoride, guanamine resin, boron nitride, silica, wood flour, and talc.
The fact that the two groups can be used together is that
Of course. The amount used is such that the above thermal mold release agent or lubricant accounts for 10 to 50% by weight in the mat layer. C. Matte agent Use an appropriate amount of the following inorganic pigment. 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 thermal mold release agents or lubricants, and they have both the functions of B and C. D Conductive powder Metal powder such as nickel, iron, copper, silver, aluminum, gold, cadmium, cobalt, chromium, magnesium, molybdenum, lead, palladium, platinum, rhodium, tin, tantalum, titanium, tungsten, zinc, zirconium, etc. Alternatively, oxides of these metal powders, carbon black, conductive carbon such as graphite, etc. are used. E. Colorants In addition to the colorants forming cyan, magenta, yellow, and black, colorants of various other colors can also be used. That is, to the matte layer, carbon black or various dyes and pigments are added as a coloring agent, selected according to the color to be imparted to the matte layer. The matte layer on the base film is formed by dissolving or dispersing the above-mentioned constituent materials in a suitable solvent, adjusting the viscosity to be suitable for coating, and applying the mixture to the base film using a commonly used coating means. The thermal transfer sheet of the present invention may include various modifications. One example is to provide a primer layer on top of the base film, which increases the adhesion between the base film and the matte layer. The primer layer can be easily created by applying known primer paints. For example, as a binder, acrylic resin, polyester resin, polyvinyl acetate resin,
Combinations of vinyl chloride/vinyl acetate resin, polyol and diisocyanate, polyol and melamine, or epoxy resin and diisocyanate are often used. Primer paints using these binders have particularly good adhesive strength when the base film is polyester. The improvement is remarkable. Another example is to provide a layer to prevent stacking between the base film and the thermal head, which may occur depending on printing conditions. The anti-stacking layer basically includes a resin and a heat release agent or a lubricant. A coating composition may be prepared using the same materials as those used to form the matte layer described above (excluding the matting agent, conductive powder, and coloring agent) and applied to the other side of the base film. [Function] By incorporating the conductive powder into the matte layer, antistatic performance can be imparted to the heat-sensitive transfer sheet. Furthermore, since it has a matte layer, it is possible to print matte characters and figures that are easy to see. Further, by pre-containing a suitable coloring agent in the matte layer so as to have the same color as the heat-melting ink layer, it is possible to provide the matte layer with a function of preventing leakage of confidential information. [Example] (Matsuto layer ink) Γ Polyester resin 6 parts by weight (Toyobo "Vylon 200") Γ Vinyl chloride/vinyl acetate copolymer resin
7 parts by weight (UCC's Vinylite VAGH) Γ Conductive carbon 5 parts by weight (Lion Akzo Co., Ltd.: ketjen
BLACK) Γ Methyl ethyl ketone 30 parts by weight Γ Toluene 30 parts by weight To the above composition, add a 50% butyl acetate solution of isocyanate (Takenate D-204) to the above composition: isocyanate = 20:3 (weight ratio , hereinafter the same) is used as matte layer ink. (Matsuto layer ink) Γ Methyl methacrylate resin 10 parts by weight (Mitsubishi Rayon "Dyna Anal BR-88") Γ Tin oxide 5 parts by weight (Mitsubishi Metals "T-1") Γ Polyethylene wax 2 parts by weight (Asahi Denka "Mark") FC-113" 30% toluene dispersion) Γ Yellow pigment (Dainichiseika 2400) 4 parts by weight Γ Toluene 20 parts by weight Γ Methyl ethyl ketone 20 parts by weight (primer layer ink) Γ Polyester resin (Toyobo "Byron 200")
3 parts by weight Γ Polyvinyl chloride/vinyl acetate copolymer resin
3 parts by weight (UCC's "Vinyrite VAGH") Γ Toluene 20 parts by weight Γ Methyl ethyl ketone 20 parts by weight Isocyanate (Takeda Products "Takenate D-
110N'') at a ratio of 46:1 to prepare a primer layer ink. (Thermofusible ink) Γ Parafine wax 10 parts by weight Γ Carnauba wax 10 parts by weight Γ Ethylene/vinyl acetate copolymer 1 part by weight (Sumitomo Chemical Sumitate HC-10) Γ Carbon black 2 parts by weight (Tokai Electrode SEAST SO") (Thermofusible ink) Carbon black of the above thermofusible ink was replaced with 2 parts by weight of yellow pigment (Dainichiseika 2400). The above-mentioned hot-melt ink and composition were kneaded at 100° C. for 6 hours using a blade kneader. Example 1 Polyethylene terephthalate (Toray) with a thickness of 6 μm was used as a base film, and the matte layer ink was applied at a coating amount of 1 g/m ² by gravure printing. On top of this matte layer ink, the above-mentioned heat-melting ink was applied to a thickness of 5 μm using a hot-melt method heated to 100° C. and a roll coating method to form a heat-sensitive transfer ink layer. Example 2 Using polyethylene terephthalate (Toray) with a thickness of 6μ as a base film, the primer layer ink was applied in a coat amount of 0.5g/by gravure printing method.
Applied in m ² . On this primer layer, the matte layer ink was applied in a coating amount of 1 g/m ² by a gravure printing method. Furthermore, on top of this matte layer ink, the above-mentioned hot-melt ink was heated to 100°C by a roll coating method using a hot melt method.
It was applied to a thickness of 5μ to form a thermal transfer ink layer. Comparative Example 1 A thermal transfer sheet in which the matte layer ink was not provided in Example 1. Comparative Example 2 A thermal transfer sheet in which the matte layer ink was not provided in Example 2. The heat-sensitive transfer sheets of Examples 1 and 2 and Comparative Examples 1 and 2 were slit into ribbons and printed using a commercially available printer. Material to be transferred: High-quality paper (Mitsubishi Paper Co., Ltd. “Hokuryoshi” 46-size/72kg) Thermal head: Thin-film thermal head Printing energy: 1mJ/dot (4×10 ^-4
cm ² ) Next, the effects of the heat-sensitive transfer sheet of the present invention in terms of matte printing, prevention of static electricity, and prevention of secret leakage are shown below. (Table.1) Generally, the matting required for printing is
Although it varies depending on the gloss level of the recording paper and the reading conditions, if the gloss level is approximately 30 or higher when measured with a gloss meter, it can be said that it is always at a sufficient level. According to the present invention, this can be easily achieved. In Table.1, if the glossiness is 30 or less, it is marked as ○, and if it is 30 or more, it is marked as ×. The antistatic effect was evaluated as ○ if the surface resistance after application of the hot-melt ink was 10 ⁹ Ω or less, and × if it was 10 ⁹ Ω or more. Regarding the security leakage prevention effect, the ribbon was observed after printing, and those where it was possible to read the areas where the heat-fusible ink had come off were evaluated as ×, and those where it was impossible to read were evaluated as ○.

[Table] Glossiness is the gloss of the printed area using a crossmeter (Murakami Shirishaku Institute "GM-3M") at a measurement angle of 60°.
Each was measured. The surface resistance was measured using a super insulation resistance meter YHP4329A-16008A. [Effects of the Invention] The thermal transfer sheet of the present invention has the structure as described above, and if it is used, matte printing,
It is possible to perform thermal transfer that has a function of preventing static electricity or preventing secret leakage.

Claims (1)

[Scope of Claims] 1. A heat-sensitive transfer sheet comprising a matte layer on the base film surface and a heat-melting ink layer on the matte layer that is peelable from the matte layer, the matte layer having the following properties: Components A, B, C A thermoplastic resin, or OH group, or COOH
A resin obtained by adding a compound or diisocyanate having two or more amino groups to a thermoplastic resin having a group, B a matting agent made of fine powder of an inorganic pigment, C a conductive powder, and the average matting depth of the matting layer is 0.15. ~
2μ, and the surface resistance value of the mat layer is 10 ⁹ Ω.
A heat-sensitive transfer sheet characterized by the following: 2. The heat-sensitive transfer sheet according to claim 1, wherein the base film is provided with a primer layer and then the matte layer is provided to increase the adhesive strength between the base film and the matte layer. 3. The thermal transfer sheet according to claim 1, wherein a layer for preventing sticking to a thermal head is provided on the other surface of the base film. 4 The conductive powder is a metal such as nickel, iron, copper, silver, aluminum, gold, cadmium, cobalt, chromium, magnesium, molybdenum, lead, palladium, platinum, rhodium, tin, tantalum, titanium, tungsten, zinc, or zirconium. powder or oxides of these metal powders or carbon black,
The heat-sensitive transfer sheet according to claim 1, which is a conductive carbon such as graphite. 5. The heat-sensitive transfer sheet according to claim 1, wherein the heat-melting ink layer and the matte layer have the same color.