JP4121938B2 - Thermal transfer sheet - Google Patents

Description

  The present invention relates to a thermal transfer sheet used in a thermal transfer printer using a heating means such as a thermal head, and more specifically, a base material film is provided with a transfer ink layer that melts or sublimates by heating on one surface of the base film, and the thermal head contacts the thermal transfer sheet. On the other side of the film, the back layer is made of a specific material, has no heat treatment such as aging, has excellent heat resistance and slip properties, and has defects in printing due to wrinkles and tailing during printing. The present invention relates to a thermal transfer sheet that prevents the occurrence of the above.

  When a heat-sensitive plastic film is used as the base material for the thermal transfer sheet, the film sticks to the thermal head during printing (sticking), and debris and slip properties are impaired due to adhesion of debris. There is a problem that breaks. For this reason, a method for forming a heat-resistant layer made of a thermosetting resin having high heat resistance has been proposed. Although this method improves the heat resistance, the slip property of the thermal head is not improved. Since the use of this curing agent is necessary, the coating liquid becomes a two-component type. Furthermore, since the base material is a plastic thin film that cannot be treated at high temperature, long-term heat treatment (aging) for several tens of hours at a relatively low temperature is required after coating in order to obtain a sufficient cured film. This is not only troublesome in the process, but if strict temperature control is not performed, wrinkles are generated during heat treatment, or the opposite surface that contacts the coated surface is bonded and blocked. is there.

  It has been proposed to add a lubricant such as silicone oil, low melting point WAX, surfactant, etc. to improve the slipping property, but when these inappropriate lubricants are used, the thermal transfer sheet is wound up. There is a problem in that it shifts to the opposite surface when it is printed and the thermal head is contaminated during printing. In addition, there is a method of adding a filler to remove these deposits, but if an inappropriate material is used, the coefficient of friction with the thermal head increases, causing wrinkles during printing, There is a problem of wearing.

In order to solve these problems, Patent Documents 1 and 2 have a back layer made of a silicone-modified polyurethane resin, Patent Document 3 has a heat-resistant protective layer made of a polysiloxane-polyamide block copolymer, and Patent Document 4 has a silicone. A heat-resistant protective layer containing a modified polyimide resin has been proposed, but because of its low heat resistance as a resin, sticking with a high-energy single print, or using a special solvent, a special exhaust device is required for manufacturing. There was a problem with the safety in the work environment. Patent Documents 5 and 6 propose a polyamide-imide resin composition, and Patent Document 7 proposes a heat-resistant protective layer containing a lubricant in a polyamide-imide resin. There was a problem in that scum was attached and the print was affected.
JP 61-184717 A JP-A-62-220385 JP-A-5-229271 JP-A-5-229272 Japanese Patent Laid-Open No. 8-113647 JP-A-8-244369 JP-A-10-297124

Further, as shown in FIG. 1, a thermal head in thermal transfer recording has a configuration in which a thermal resistance layer 5, a heating resistor 2, an electrode 3, and an abrasion resistant layer 4 are provided on a heat dissipation substrate 1, and a thin film type is used. in use. The heat dissipation substrate 1 is made of ceramics and the like, and the thermal resistance layer 5 is made of glass or the like and is formed so as to be raised on the heat dissipation substrate 1. The thickness of the top is 20 to 150 μm, and the thermal conductivity is about 0.1 to 2 Watt / m · deg. The heating resistor 2 is made of Ta ₂ N, W, Cr, Ni—Cr, SnO _2, etc., and is formed in a line shape using a thin film forming technique such as vacuum deposition, CVD, sputtering, etc., and has a thickness of 0.05 to It is about 3 μm. The electrode 3 is made of Al or the like and is formed for energization of the heating resistor 2 except for the top of the heat resistance layer 5, and has a thickness of about 0.1 to 3 μm. The wear resistant layer 4 is made of Ta ₂ O ₃ , SiN, SiC or the like.

  Under such thermal head conditions, various full-color image patterns are reproduced and used as thermal transfer images. However, among the many printing conditions, under the printing conditions where the dark solid printing part and the halftone are adjacent, the thermal energy applied to the thermal head changes suddenly from a high level to a low level. There is a problem in that tail stains occur in the halftone portion, which is considered to be the effect of debris temporarily accumulated at the contact portion between the head and the back side of the thermal transfer sheet.

  Therefore, in order to solve the problems as described above, the present invention uses a one-component coating liquid that uses a general solvent without using a special solvent that is problematic in terms of production and work environment, To provide a thermal transfer sheet provided with a back layer that has excellent heat resistance and slip properties without requiring heat treatment such as aging, and prevents wrinkles during printing and defects in printing due to tailing, etc. With the goal.

The invention according to claim 1 is a thermal transfer sheet in which a transfer ink layer that is melted or sublimated by heating is provided on one side of a base film, and a back layer is provided on the other side of the base film in contact with the thermal head. In this case, the back layer is made of a mixture of a polyamideimide resin having a Tg of 200 ° C. or higher by differential thermal analysis and a polyamideimide silicone resin having a Tg of 200 ° C. or higher, and a polyvalent metal salt of an alkyl phosphate ester. And a metal salt of an alkylcarboxylic acid, a phosphate ester surfactant and an inorganic filler , and the phosphate ester surfactant content is 1 to 30 parts by mass per 100 parts by mass of the binder There, transfer an average particle diameter of the inorganic filler, characterized in that 0.05 to 5 [mu] m, and Mohs hardness of 3 or less Shi It is a door.

  In the invention according to claim 2, the mixing ratio of the mixture of the polyamideimide resin (A) and the polyamideimide silicone resin (B) according to claim 1 is A: B = 1 to 5: 5 to It is characterized by 1. As a third aspect, the mixture of the alkyl phosphate ester polyvalent metal salt (C) and the alkyl carboxylic acid metal salt (D) according to the first aspect has a mass ratio of C: D = 1: 9 to 9: It is characterized by 1. According to a fourth aspect of the present invention, the content of the phosphate ester surfactant according to the first aspect is 1 to 30 parts by mass per 100 parts by mass of the binder.

  As a fifth aspect, the inorganic filler according to the first aspect has an average particle size of 0.05 to 5 μm and a Mohs hardness of 3 or less. As a sixth aspect, the inorganic filler according to the first aspect is talc, mica and / or calcium carbonate. As a seventh aspect, the content of the inorganic filler according to the first aspect is 2 to 20 parts by mass per 100 parts by mass of the binder.

  The back layer of the present invention can be applied in a one-component state with a general solvent, and the thermal transfer sheet provided with the back layer is provided with a transfer ink layer that is melted or sublimated by heating on one side of the base film, A mixture of a polyamideimide resin having a Tg of 200 ° C. or higher and a polyamideimide silicone resin having a Tg of 200 ° C. or higher as well as a back layer provided on the other surface of the base film. In addition, a phosphate ester surfactant and an inorganic filler can be used to prevent the film from fusing due to the heat of the thermal head, and it is highly slippery and can withstand high energy. Defects due to printing such as wrinkles and tailing, which are thought to be due to temporary accumulation of residue on the thermal head, were prevented.

Hereinafter, each layer constituting the thermal transfer sheet of the present invention will be described in detail.
(Base film)
The base film constituting the thermal transfer sheet of the present invention may be any base film having a conventionally known level of heat resistance and strength, for example, about 0.5 to 50 μm, preferably about 3 to 10 μm. Thickness polyethylene terephthalate film, 1,4-polycyclohexylene dimethylene terephthalate film, polyethylene naphthalate film, polyphenylene sulfide film, polysylene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, Cellulose, cellulose derivatives such as cellulose acetate, polyethylene film, polyvinyl chloride film, nylon film, polyimide film, ionomer film, etc., capacitors -Papers such as paper, paraffin paper, paper, and non-woven fabric, or a composite of paper, non-woven fabric and resin may be used.

(Back layer)
The thermal transfer sheet of the present invention is provided with a transfer ink layer that is melted or sublimated by heating on one side of the base film as described above, and a back layer is provided on the other side of the base film in contact with the thermal head, It has a feature in the structure of the back layer. As the binder constituting the back layer, a polyamideimide resin (A) and a polyamideimide silicone resin (B) are mixed and used. The mass mixing ratio is preferably in the range of A: B = 1 to 5: 5 to 1, and more preferably in the range of 1 to 2: 2 to 1. When there is more polyamideimide silicone resin than 1: 5, the heat resistance of the back layer formed tends to be insufficient, and head residue tends to occur. When there is less polyamideimide silicone resin than 5: 1, the slipping property of the back layer formed becomes poor. Insufficient thermal head sticking is likely to occur.

  The polyamideimide resin and the polyamideimide silicone resin used in the present invention are the same as those described in JP-A-8-244369, and among them, those having a Tg of 200 ° C. or more by differential thermal analysis are used. It is preferable. In addition, the polyamideimide silicone resin used in the present invention is obtained by copolymerizing with a polyamidoimide using a polyfunctional silicone compound having a molecular weight of 1,000 to 6,000 or by modifying the polyamidoimide with silicone. The amount of silicone is particularly preferably 0.01 to 0.3 with respect to the polyamideimide resin 1 in terms of mass ratio.

  The polyamide-imide resin used in the present invention is preferably soluble in an alcohol solvent. The polyfunctional silicone compound that is copolymerized or modified with the polyamideimide resin is preferably a silicone compound having any one of a hydroxyl group, a carboxyl group, an epoxy group, an amino group, and an acid anhydride group.

  If the Tg of the polyamideimide resin and the polyamideimide silicone resin is less than 200 ° C., the heat resistance is insufficient, and if the amount of copolymerization or modification by the silicone is too small, a back layer having sufficient lubricity in the above mixing range can be obtained. This is likely to cause sticking of the thermal head. On the other hand, if the amount of copolymerization or modification by silicone is too large, the heat resistance and film strength of the back layer formed will decrease.

  The back layer in the present invention contains a polyvalent metal salt of an alkyl phosphate ester and a metal salt of an alkyl carboxylic acid. The polyvalent metal salt of an alkyl phosphate ester can be obtained by substituting the alkali metal salt of an alkyl phosphate ester with a polyvalent metal. This is known as an additive for plastics, and various grades are available.

In the present invention, a particularly preferred polyvalent metal salt of an alkyl phosphate is represented by the following structural formula 1 (wherein R is an alkyl group having 12 or more carbon atoms, M is an alkaline earth metal, zinc or aluminum). , N represents the valence of M), and R is an alkyl group having 12 or more carbon atoms such as cetyl group, lauryl group and stearyl group, particularly stearyl group, and M is such as barium, calcium and magnesium. Those which are alkaline earth metals, zinc or aluminum are preferred.

In addition, a metal salt of an alkylcarboxylic acid that is preferable in the present invention is represented by the following structural formula 2 (wherein R is an alkyl group having 11 or more carbon atoms, M is an alkaline earth metal, zinc, aluminum, or lithium, and n is And R represents an alkyl group having 11 or more carbon atoms such as a hexadecyl group, a dodecyl group, a heptadecyl group, particularly a dodecyl group, a heptadecyl group, and M represents barium, calcium, magnesium, etc. Of the alkaline earth metals, zinc, aluminum or lithium.

  When the carbon number of R is small, it is difficult to obtain industrial use and costs, and further, since the overall molecular weight is lowered, bleeding from the back layer of the lubricant and contamination to other parts become a problem. M can select a metal species depending on the temperature condition used during thermal transfer. For reference, melting points are barium-based 190 ° C. or higher, calcium-based 140 to 180 ° C., magnesium-based 110 to 140 ° C., zinc-based 110 to 140 ° C., aluminum-based 110 to 170 ° C., lithium-based 200 ° C. That's it. In the present invention, magnesium, zinc, and aluminum are particularly preferable.

  The mixing ratio of the mixture of the polyvalent metal salt (C) of the alkyl phosphate ester and the metal salt (D) of the alkyl carboxylic acid is C: D = 1: 9 to 9: 1 in mass ratio. Preferably, C: D = 2: 8 to 8: 2. If the amount of the metal salt of the alkyl carboxylic acid is too large, residue tends to adhere to the thermal head, while if it is too small, the effect of the addition is lost.

  The mixture is desirably in a ratio of 1 to 100 parts by weight per 100 parts by weight of the binder, and particularly preferably in the range of 5 to 20 parts by weight. If the amount of the mixture of the polyvalent metal salt of the alkyl phosphate ester and the metal salt of the alkyl carboxylic acid is less than the above range, sufficient releasability of the thermal head during heat application cannot be obtained, and thermal It becomes easy for the residue to adhere to the head. On the other hand, if the amount used exceeds the above range, the physical strength of the back layer is lowered, which is not preferable.

  Examples of the phosphate ester-based surfactant to be contained in the back layer as a lubricant include (1) long-chain alkyl phosphate esters, for example, a saturated or non-saturated alkyl having 6 to 20 carbon atoms, preferably 12 to 18 carbon atoms. Saturated higher alcohols, for example, mono and / or diesters of phosphoric acid with cetyl alcohol, stearyl alcohol, oleyl alcohol and the like, (2) phosphate esters such as polyoxyalkylene alkyl ether or polyoxyalkylene alkyl aryl ether, (3 ) Alkyl oxide adducts of the saturated or unsaturated alcohols (usually 1 to 8 moles added) or alkylphenols or alkylnaphthols (nonylphenol, dodecyl) having at least 1, preferably 1 to 2 carbon atoms. Phenol, diphenylphenol Alkylene oxide adducts (typically nonionic or anionic phosphate ester surfactants such as phosphoric acid mono- or diester salt of addition mole number of 1 to 8) and the like etc.).

  The phosphate ester surfactant is preferably contained in the back layer at a ratio of 1 to 30 parts by mass per 100 parts by mass of the binder, and particularly preferably in the range of 3 to 10 parts by mass. If the amount of the phosphate ester-based surfactant used is less than the above range, sufficient thermal head releasability at the time of heat application cannot be obtained, and debris tends to adhere to the thermal head. On the other hand, if the amount used exceeds the above range, the physical strength of the back layer is lowered, which is not preferable.

  As the inorganic filler to be contained in the back layer, inorganic fine particles having a Mohs hardness of preferably 3 or less are added. If the Mohs hardness exceeds 3, the thermal head wears easily and the friction coefficient with the thermal head increases. Especially, the wrinkle is generated due to the large difference in the friction coefficient between non-printing and printing. It becomes easy to do. Further, when the filler is detached from the back layer, a print defect generated on the print screen becomes remarkable, which is not preferable.

  Various inorganic fillers are known per se in the present invention, and examples thereof include talc, kaolin, mica, sekiboku, nitrate, gypsum, blues stone, graphite, calcium carbonate, molybdenum disulfide, and the like, heat resistance and lubricity. Among these, talc, mica and calcium carbonate are particularly preferable.

In the case of the above-mentioned inorganic filler, in the case of a naturally-occurring inorganic filler, if the impurities include those having a Mohs hardness of more than 3, the present invention can be used if the content of these impurity particles is less than 5% by mass. Can be used without problems. The Mohs hardness is measured by a Mohs hardness meter. The Mohs hardness tester is It was devised by Mohs, and 10 kinds of minerals ranging from soft minerals to harder minerals were put in a box, and the hardness ranking was shown as 1 degree, 2 degrees, ... 10 degrees from the softest one. is there. Standard minerals are as follows (numbers indicate hardness).
1: Kaseki, 2: Gypsum, 3: Boulder stone, 4: Firefly stone, 5: Linkai stone, 6: Seiko stone, 7: Sekiei, 8: Topaz, 9: Corundum 10: Diamond

  When the surface of a mineral sample for which hardness is desired is to be scratched by scratching with these minerals, the hardness can be compared by the resistance (whether it is scratched or not). For example, when the calcite is scratched, the hardness of the sample is greater than 3 degrees. If the fluorite is scratched and the fluorite is not scratched, the hardness of the sample is less than 4 degrees. At this time, the hardness of the sample is 3 to 4 or 3.5. When the scratches are somewhat scratched, the hardness of the sample shows the same level of hardness as the standard mineral used. The hardness of the Mohs hardness tester is just an order, not an absolute value.

  Further, when the filler is mixed at a rate of 2 to 20 parts by mass per 100 parts by mass of the binder, the above-mentioned lubricity and heat resistance are good, and particularly in the range of 5 to 15 parts by mass. preferable. If it is less than this range, no improvement in heat resistance is observed, and fusion is observed in the thermal head. On the other hand, if this range is exceeded, the flexibility and film strength of the back layer will be reduced.

  The average particle size of the filler is also important and varies depending on the thickness of the back layer to be formed, but is preferably in the range of 0.05 to 5 μm, particularly preferably in the range of 0.1 to 2 μm. If the average particle size exceeds 5 μm, the thermal head is likely to wear, and printing flaws appearing on the print screen when the filler is detached from the back layer become unfavorable. On the other hand, an average particle size of less than 0.05 μm is not preferable because the cleaning property when debris adheres to the thermal head is poor.

In order to form the back layer, a coating liquid is prepared by dissolving or dispersing the above materials in toluene / ethanol = 1/1 solvent as a binder solvent, and this coating liquid is prepared using a gravure coater, roll coater, It is formed by applying and drying by a conventional coating method such as a wire bar. The coating amount of the back layer is 0.7 g / m ² or less, preferably 0.1 to 0.6 g / m ^{2 on} a dry solid basis, and a back layer having sufficient performance can be formed. If the thickness of the back layer is too thin, the functions of the back layer cannot be fully exhibited. On the other hand, if the back layer is too thick, the sensitivity during printing is not preferred.

(Transfer ink layer)
As the transfer ink layer to be formed on the other surface of the base film, in the case of a sublimation type thermal transfer sheet, a layer containing a sublimation dye, that is, a heat sublimation dye layer is formed. In the case of this thermal transfer sheet, a hot-melt ink layer colored with a pigment or the like is formed. Hereinafter, although the case of a sublimation type thermal transfer sheet will be described as a representative example, the present invention is not limited to only a sublimation type thermal transfer sheet.

  As the dye used in the sublimation type transfer ink layer, any of the dyes used in conventionally known thermal transfer sheets can be used in the present invention and is not particularly limited. For example, some preferred dyes include red dyes such as MS RED G, Macro Red Bioret®, Ceres Red 7B, Samaron Red HBSL, and Resolin Red F3BS, and yellow dyes include hollon brilliant yellow 6GL. , PTY-52, Macrolex Yellow 6G, and the like, and examples of the blue dye include Kayaset Blue 714, Waxolin Blue AP-FW, Holon Brilliant Blue-SR, MS Blue 100, and the like.

  Examples of preferable binder resins for supporting the above dyes include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose tributyrate, polyvinyl alcohol, Examples thereof include vinyl resins such as polyvinyl acetate, polyvinyl butyral, polyvinyl acetoacetal, and polyvinylpyrrolidone, acrylic resins such as poly (meth) acrylate and poly (meth) acrylamide, polyurethane resins, polyamide resins, and polyester resins. . Among these, cellulose-based, vinyl-based, acrylic-based, urethane-based, and polyester-based resins are preferable from the viewpoints of heat resistance, dye transferability, and the like.

  The dye layer is formed by adding one or more additives such as the above dye and binder as necessary to one side of the base film, such as a release agent or inorganic fine particles, toluene, methyl ethyl ketone, ethanol, Dispersed in a suitable organic solvent such as isopropyl alcohol, cyclohequinone, DMF or dispersed in an organic solvent or water, for example, gravure printing method, screen printing method, reverse roll coating printing method using gravure plate It can be formed by applying and drying by means such as.

Coating amount in dry solid basis 0.2 to 5.0 g / m ² of the dye layer formed in this manner, and preferably about 0.4 to 2.0 g / m ^2, also, the dye layer The sublimable dye is preferably present in an amount of 5 to 90% by weight, preferably 10 to 70% by weight of the weight of the dye layer. The dye layer to be formed is formed by selecting one of the dyes when the desired image is monocolor, and when the desired image is a full color image, for example, an appropriate cyan, Magenta and yellow (and optionally black) are selected to form yellow, magenta and cyan (and optionally black) dye layers.

  The image receiving sheet, which is a transfer material used for forming an image using the thermal transfer sheet as described above, may be anything as long as its recording surface has dye acceptability with respect to the above dye, In the case of paper, metal, glass, synthetic resin, etc. that do not have dye receptivity, a dye receptive layer may be formed on at least one surface thereof. In the case of a heat melting type thermal transfer sheet, the material to be transferred is not particularly limited and may be ordinary paper or plastic film. As a printer used when performing thermal transfer using the above thermal transfer sheet and the above image receiving sheet, a known thermal transfer printer can be used as it is, and is not particularly limited.

Next, an Example and a comparative example are given and this invention is further explained in full detail. In the text, “part” or “%” is based on mass unless otherwise specified. The following materials were each adjusted with ethanol / toluene = 1/1 (mass ratio) solvent so as to have a solid content of 10%, and after stirring, dispersed for 3 hours with a paint shaker to obtain a back layer ink. Each of these inks is coated on one side of a polyester film (Lumirror, thickness 4.5 μm, manufactured by Toray Industries, Inc.) using a wire bar coater so that the coating amount is 0.5 g / m ^{2 on} a mass basis upon drying. And dried for 1 minute in an oven at 80 ° C. to form a back layer.

(Back layer material)
-Polyamideimide resin (HR-15ET, manufactured by Toyobo Co., Ltd.) 50 parts- Polyamideimide silicone resin (HR-14ET, manufactured by Toyobo Co., Ltd.) 50 parts-Phosphate ester surfactant (Plysurf A208S, Daiichi Kogyo Seiyaku Co., Ltd.)
5 parts ・ Zinc stearyl phosphate (LBT-1830 refinement, manufactured by Sakai Chemical Co., Ltd.) 10 parts ・ Zinc stearate (GF-200, manufactured by NOF Corporation) 10 parts ・ Polyester resin (Byron 220, Toyobo Co., Ltd.) ) Made) 3 parts ・ Inorganic filler (talc, average particle size 4.2 μm, Mohs hardness 3) 10 parts

  On the other surface of the substrate film, a dye layer was provided as a transfer ink layer to obtain a thermal transfer sheet of Example 1 of the present invention. The dye layer was matched to the conditions of the dye layer of the thermal transfer sheet for sublimation printer CP8000 manufactured by Mitsubishi Electric Corporation. In addition, what is used as an image receiving sheet in the following evaluation is an image receiving sheet (standard type) for a sublimation printer CP8000 manufactured by Mitsubishi Electric Corporation.

The material for the back layer in the thermal transfer sheet prepared in Example 1 was changed to the following, and the other conditions were all the same as in Example 1 to prepare the thermal transfer sheet of Example 2.
(Back layer material)
-Polyamideimide resin (HR-15ET, manufactured by Toyobo Co., Ltd.) 50 parts- Polyamideimide silicone resin (HR-14ET, manufactured by Toyobo Co., Ltd.) 50 parts-Phosphate ester surfactant (Plysurf M208BM, Daiichi Kogyo Seiyaku Co., Ltd.)
5 parts ・ Zinc stearyl phosphate (LBT-1830 refinement, manufactured by Sakai Chemical Co., Ltd.) 10 parts ・ Zinc stearate (GF-200, manufactured by NOF Corporation) 10 parts ・ Polyester resin (Byron 220, Toyobo Co., Ltd.) ) Made) 3 parts ・ Inorganic filler (talc, average particle size 4.2 μm, Mohs hardness 3) 10 parts

The material for the back layer in the thermal transfer sheet produced in Example 1 was changed to the following, and the other conditions were all the same as in Example 1 to produce the thermal transfer sheet of Example 3.
(Back layer material)
-Polyamideimide resin (HR-15ET, manufactured by Toyobo Co., Ltd.) 50 parts- Polyamideimide silicone resin (HR-14ET, manufactured by Toyobo Co., Ltd.) 50 parts-Phosphate ester surfactant (Plysurf M208BM, Daiichi Kogyo Seiyaku Co., Ltd.)
5 parts ・ Zinc stearyl phosphate (LBT-1830 refinement, manufactured by Sakai Chemical Co., Ltd.) 10 parts ・ Zinc stearate (GF-200, manufactured by NOF Corporation) 10 parts ・ Polyester resin (Byron 220, Toyobo Co., Ltd.) ) Made) 3 parts ・ Inorganic filler (mica, average particle size 3.5 μm, Mohs hardness 2.5 10 parts)

(Comparative Example 1)
The material for the back layer in the thermal transfer sheet produced in Example 1 was changed to the following, and the other conditions were all the same as in Example 1 to produce a thermal transfer sheet of Comparative Example 1.
(Back layer material)
Polyamideimide resin (HR-15ET, manufactured by Toyobo Co., Ltd.) 50 parts Polyamideimide silicone resin (HR-14ET, manufactured by Toyobo Co., Ltd.) 50 parts 10 parts) Zinc stearate (GF-200, manufactured by Nippon Oil & Fats Co., Ltd.) 10 parts Polyester resin (Byron 220, manufactured by Toyobo Co., Ltd.) 3 parts Inorganic filler (talc, average particle size 4 .2 μm, Mohs hardness 3) 10 parts

(Comparative Example 2)
The material for the back layer in the thermal transfer sheet prepared in Example 1 was changed to the following, and the other conditions were the same as in Example 1 to prepare a thermal transfer sheet of Comparative Example 2.
(Back layer material)
-Polyamideimide resin (HR-15ET, manufactured by Toyobo Co., Ltd.) 50 parts- Polyamideimide silicone resin (HR-14ET, manufactured by Toyobo Co., Ltd.) 50 parts-Phosphate ester surfactant (Plysurf M208BM, Daiichi Kogyo Seiyaku Co., Ltd.)
50 parts ・ Zinc stearyl phosphate (LBT-1830 refined, manufactured by Sakai Chemical Co., Ltd.) 10 parts ・ Zinc stearate (GF-200, manufactured by NOF Corporation) 10 parts ・ Polyester resin (Byron 220, Toyobo Co., Ltd.) ) Made) 3 parts ・ Inorganic filler (talc, average particle size 4.2 μm, Mohs hardness 3) 10 parts

(Comparative Example 3)
The material for the back layer in the thermal transfer sheet prepared in Example 1 was changed to the following, and the other conditions were the same as in Example 1 to prepare a thermal transfer sheet of Comparative Example 2.
(Back layer material)
-Polyamideimide resin (HR-15ET, manufactured by Toyobo Co., Ltd.) 50 parts- Polyamideimide silicone resin (HR-14ET, manufactured by Toyobo Co., Ltd.) 50 parts-Phosphate ester surfactant (Plysurf M208BM, Daiichi Kogyo Seiyaku Co., Ltd.)
5 parts ・ Zinc stearyl phosphate (LBT-1830 refinement, manufactured by Sakai Chemical Co., Ltd.) 10 parts ・ Zinc stearate (GF-200, manufactured by NOF Corporation) 10 parts ・ Polyester resin (Byron 220, Toyobo Co., Ltd.) )) 3 parts ・ Inorganic filler (talc, average particle size 4.9 μm, Mohs hardness 7) 10 parts

(Comparative Example 4)
The material for the back layer in the thermal transfer sheet prepared in Example 1 was changed to the following, and the other conditions were the same as in Example 1 to prepare a thermal transfer sheet of Comparative Example 2.
(Back layer material)
-Polyamideimide resin (HR-15ET, manufactured by Toyobo Co., Ltd.) 50 parts- Polyamideimide silicone resin (HR-14ET, manufactured by Toyobo Co., Ltd.) 50 parts-Phosphate ester surfactant (Plysurf M208BM, Daiichi Kogyo Seiyaku Co., Ltd.)
5 parts ・ Zinc stearyl phosphate (LBT-1830 refinement, manufactured by Sakai Chemical Co., Ltd.) 10 parts ・ Zinc stearate (GF-200, manufactured by NOF Corporation) 10 parts ・ Polyester resin (Byron 220, Toyobo Co., Ltd.) ) Made) 3 parts ・ Inorganic filler (talc, average particle size 7.4 μm, Mohs hardness 3) 10 parts

The following tests were conducted on the thermal transfer sheets of Examples and Comparative Examples obtained as described above.
[Thermal Head Abrasion] A solid image was continuously printed for 10 km with a sublimation printer (trade name CP8000, manufactured by Mitsubishi Electric Corporation), and the amount of abrasion of the protective film of the thermal head was measured.
(Evaluation criteria)
○: Less than 1 μm △: 1 to 3 μm
×: over 3μ

[Adhesiveness of thermal head residue] Thermal head heating element when printing 50m% diagonal pattern with thermal load (KST-105-13FAN21-MB (manufactured by Kyocera)) with load of 4kgf and printing energy of 0.44mJ / dot for 100m The amount of deposits on the top was observed with a microscope.
(Evaluation criteria)
○: Less than 3,000 mm △: 3,000 to 5,000 mm
×: Over 5,000Å

[Print stain] A solid pattern and a halftone continuous pattern were printed with a sublimation printer (trade name CP8000 manufactured by Mitsubishi Electric Corporation), and the presence or absence of print stain due to tailing was visually observed.
(Evaluation criteria)
○: No print stain due to tailing.
Δ: Print stains due to tailing are slightly observed, but there is no practical problem.
X: There is a print stain due to tailing, which is a print defect.

[Print wrinkles] A solid image was printed with a sublimation printer (product name CP8000, manufactured by Mitsubishi Electric Corporation), and the number of wrinkles generated per screen was visually confirmed.
(Evaluation criteria)
○: None △: 1 to 3 ×: More than 3

It is a schematic block diagram of the thermal head in thermal transfer recording.

Explanation of symbols

1 Heat Dissipation Board 2 Heating Resistor 3 Electrode 4 Abrasion Resistant Layer 5 Thermal Resistance Layer

Claims (5)

In a thermal transfer sheet in which a transfer ink layer that is melted or sublimated by heating is provided on one side of a base film, and a back layer is provided on the other side of the base film that is in contact with the thermal head, the back layer is differential thermal analysis. A mixture of a polyamidoimide resin having a Tg of 200 ° C. or more and a polyamidoimide silicone resin having a Tg of 200 ° C. or more, and a mixture of a polyvalent metal salt of an alkyl phosphate and a metal salt of an alkyl carboxylic acid And a phosphate ester surfactant and an inorganic filler, and the content of the phosphate ester surfactant is 1 to 30 parts by mass per 100 parts by mass of the binder, and the average particle size of the inorganic filler A thermal transfer sheet characterized by having a Mohs hardness of 3 or less of 0.05 to 5 μm .   The mixing ratio of the mixture of the polyamide-imide resin (A) and the polyamide-imide silicone resin (B) is A: B = 1 to 5: 5 to 1 in mass ratio. Thermal transfer sheet.   The mixture of the polyvalent metal salt (C) of the alkyl phosphate ester and the metal salt (D) of the alkyl carboxylic acid has a mass ratio of C: D = 1: 9 to 9: 1. Item 2. The thermal transfer sheet according to Item 1.   The thermal transfer sheet according to claim 1, wherein the inorganic filler is talc, mica, and / or calcium carbonate.   The thermal transfer sheet according to claim 1, wherein the content of the inorganic filler is 2 to 20 parts by mass per 100 parts by mass of the binder.

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