JP2008132771A - Thermal transfer image receiving sheet and thermal transfer recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer image receiving sheet which prevents abnormal transfer in printing to obtain a sufficiently satisfactory printed matter, by causing no blur on the printed matter, nor roughening on the receiving layer surface, under the condition of high-speed thermal transfer recording, and a thermal transfer recording method. <P>SOLUTION: In the thermal transfer image receiving sheet constituted by forming a sublimable dye-accepting layer on at least one side of a base sheet, the thermal transfer image receiving sheet is used under the condition of high-speed thermal transfer recording, wherein the binder resin composing the receiving layer has a storage modulus G'[Pa] of dynamic viscoelasticity data at 180°C of 1.0×10<SP>5</SP>or more and a loss modulus G"[Pa] at 180°C of 1.0×10<SP>5</SP>or more. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermal transfer image-receiving sheet and a thermal transfer recording method, and more specifically, in a thermal transfer image-receiving sheet provided with a sublimable dye-receiving layer on at least one surface of a substrate sheet, a dye layer containing a sublimable dye on the substrate. The present invention relates to a thermal transfer image receiving sheet and a thermal transfer recording method, which are used in combination with a thermal transfer sheet provided in the above, and prevent the printed matter from fading and the surface of the receiving layer from being roughened under the conditions for increasing the speed of thermal transfer recording.

  Conventionally, characters and images are formed on a transfer medium using a thermal transfer method. As the thermal transfer method, a thermal sublimation transfer method and a thermal fusion transfer method are widely used. Of these, the heat-sensitive sublimation transfer method uses a sublimation dye as a color material, and uses a heating device such as a thermal head or laser light whose heat is controlled according to image information, and uses a sublimation dye layer on the thermal transfer sheet. In this method, an image is formed by transferring the dye inside to a transfer medium such as a thermal transfer image receiving sheet. This heat-sensitive sublimation transfer system can control the amount of dye transfer in dot units by heating for a very short time. The image formed in this way is very clear because the coloring material used is a dye and is excellent in transparency, so the resulting image is excellent in halftone reproducibility and gradation, An extremely high-definition image can be obtained. For this reason, a high quality image comparable to a full-color silver salt photograph can be obtained.

  Due to the development of various hardware and software related to multimedia, this thermal transfer system is a full color hard copy system for analog images such as digital graphics and video such as still images by computer graphics, satellite communications and CD-ROM. As the market is expanding. The specific uses of the thermal transfer image receiving sheet by this thermal transfer method are diverse. Typical examples include printing proofs, image output, OHP sheets for presentations, design and design output for CAD / CAM, various medical analyzers such as CT scans and endoscope cameras, and measurements. Output of equipment and as an alternative to instant photos, output of ID photos, ID cards, credit cards, other face photos to other cards, and composite photos at amusement facilities such as amusement parks, game centers, museums, and aquariums , Souvenir photos, picture postcards, etc.

  With the widespread use of such thermal transfer systems, the printing speed of thermal transfer recording systems is increasing, and even if the conventional thermal transfer sheet is printed with conventional thermal energy, sufficient transfer sensitivity cannot be obtained. Problems have arisen. Furthermore, there is a demand for a higher density and clearer image printed by thermal transfer, and an attempt to improve transfer sensitivity is required. In view of this, improvements have been made such as obtaining a desired transfer sensitivity by reducing the thickness of the base sheet and printing with conventional thermal energy, or increasing the thermal energy during printing. However, in these methods, heat damage to the thermal transfer sheet is large, and the dye layer and the dye receiving layer of the transfer material are thermally fused, or not only the dye of the dye layer but also the entire dye layer is transferred to the transfer material. So-called abnormal transfer has occurred, and defects such as uneven printing on the transfer material due to generation of wrinkles on the thermal transfer sheet during thermal transfer recording have become apparent. In contrast to this, attempts have been made using a technique for adding a large amount of a release agent such as silicone into the receiving layer as shown in Patent Documents 1 and 2, but the storability of the printed matter is poor and practically used. Problems arise.

  The current printer usually has a printing speed of 0.7 to 5.0 ms / line, but when printing at a high speed (0.7 to 2.0 ms / line), it is compared with the normal conditions. The applied power instantaneously increases. For this reason, when a thermal transfer image of black was formed by superimposing three colors of dyes from each dye layer in the order of yellow, magenta, and cyan under high-speed thermal transfer recording conditions, this was caused by insufficient heat resistance of the receiving layer. As a result, the glossy surface of the printed material is lost (matte). In addition, due to the thermal damage received when printing yellow and magenta, the original dye-accepting ability cannot be expressed during cyan printing, resulting in a phenomenon in which the redness of thermal transfer prints that should be black becomes strong (fading) There is a case. In particular maxO. D. However, in the high density (1.9 to 2.1) portion, the above-described matting and blurring phenomenon easily occurs. In particular, the phenomenon of fading occurs locally, and as a result, the print density of the faint portion decreases.

  As described above, when the dye is transferred from the thermal transfer sheet to the thermal transfer image receiving sheet, the thermal transfer sheet and the thermal transfer image receiving sheet are fused, and cannot be smoothly peeled, and the surface of the printed material becomes a mat (rough surface). . In other words, the surface of the printed material becomes rougher as the printing proceeds with yellow of the first color and magenta of the second color. Further, when printing cyan of the third color, thermal unevenness occurs, or at the same time, a phenomenon occurs in which the receiving layer of the thermal transfer image receiving sheet cannot withstand heat and is taken to the thermal transfer sheet side. This is determined to be the cause of blurring and matting. Further, the higher the density of the printed material, the more the matting or fading is likely to occur because the plasticization of the receiving layer is promoted.

On the other hand, many attempts have been made to devise and improve the composition of the receiving layer in the thermal transfer image receiving sheet. (For example, see Patent Documents 3, 4, and 5) In Patent Document 3, a cured resin coating layer obtained by applying a radiation-curable resin-containing coating composition and radiation curing is used as a dye-receiving layer, and the cured resin coating The glass transition point of the layer (tan δ peak value in dynamic viscoelasticity measurement) is 0 ° C. or higher and 80 ° C. or lower, and the cured resin coating layer at the glass transition point + 30 ° C. obtained in the dynamic viscoelasticity measurement It is proposed that the storage elastic modulus (E ′) of 1 × 10 ⁷ Pa or more and 1 × 10 ⁸ Pa or less.

In Patent Document 4, the main component polymer in the image receiving layer exhibits a melt viscosity of 10 ⁶ Pa · S or higher at 140 ° C. and a melt viscosity of 10 ⁵ Pa · S or higher at 160 ° C. It has been proposed to be composed of at least one member selected from a polymer containing an ester bond unit therein and a crosslinked product thereof.

In Patent Document 5, the dye image-receiving layer is composed of (a) 50 mol% or more of a diol component containing an alkylene glycol adduct of bisphenol A having a defined structure and (b) 50% by mole or more of a dicarvolonic acid containing terephthalic acid. At least one selected from a polyester polymer obtained by a copolycondensation reaction with an acid component and having a glass transition point of 40 to 70 ° C. and an elastic modulus of 5 × 10 ⁸ Pa or more at 60 ° C., and a crosslinked product thereof. It describes that it contains a member as a main component.

However, with the thermal transfer image receiving sheet as described above, even if the dye transfer sensitivity at the time of thermal transfer is improved, it reaches a level that can sufficiently eliminate matting and blurring on the surface of a printed material created under high-speed printing conditions. This is not a situation.
JP-A-8-108636 JP 2006-264543 A JP 2003-63154 A Japanese Patent No. 2904544 Japanese Patent No. 2933338

  Therefore, in order to solve the above-mentioned problems, the prints are sufficiently satisfactorily prevented under the conditions of increasing the speed of thermal transfer recording, so that the prints are not faded or the receiving layer surface is roughened, and abnormal transfer in the prints is prevented. It is an object of the present invention to provide a thermal transfer image receiving sheet and a thermal transfer recording method from which a product can be obtained.

The invention according to claim 1 is a thermal transfer image-receiving sheet in which a sublimable dye-receiving layer is formed on at least one surface of a base sheet, and the thermal transfer image-receiving sheet is used under high-speed thermal transfer recording conditions. The binder resin constituting the receiving layer has a storage elastic modulus G ′ [Pa] of dynamic viscoelasticity data at 180 ° C. of 1.0 × 10 ⁵ or more and a loss elastic modulus G ″ [Pa] at 180 ° C. . there is characterized in that it is 1.0 × 10 ⁵ or more claims 2 invention, the binder resin in the receiving layer according to claim 1, vinyl chloride - are vinyl acetate copolymer resin It is characterized by that.

The invention according to claim 3 is characterized in that the number average molecular weight of the vinyl chloride-vinyl acetate copolymer resin used as the binder resin in the receiving layer according to claim 1 or 2 is 35,000 or more. . As for invention of Claim 4, the glass transition temperature of the vinyl chloride-vinyl acetate copolymer resin used as binder resin in the receiving layer as described in any one of Claims 1-3 is 72 degreeC or more. It is characterized by that. The invention according to claim 5 is a thermal transfer image in which a dye layer containing a heat transferable dye and a binder is provided on a substrate, and a sublimation dye receiving layer is formed on the substrate sheet. In a thermal transfer recording method in which an image is formed on a receiving layer by superimposing a sheet and heating according to image information to cause heat transfer of the dye, the thermal transfer recording speed is 0.7 to 2.0 ms / line. And thermal transfer recording is performed using the thermal transfer image-receiving sheet according to any one of claims 1 to 4.
Here, ms / line used as a unit of the printing speed is a time required for printing one line in the sub-scanning direction (image receiving paper feeding direction at the time of printing) by the thermal head. In the present application, since a thermal head having a resolution of 300 lines per inch (hereinafter 300 dpi) is used, it is the same as the time required for printing to 1/300 inch.

The thermal transfer image-receiving sheet of the present invention has a structure in which a sublimable dye-receiving layer is formed on at least one surface of a base sheet, and the thermal transfer image-receiving sheet is used under high-speed thermal transfer recording conditions. The constituent binder resin has a storage elastic modulus G ′ [Pa] of dynamic viscoelasticity data at 180 ° C. of 1.0 × 10 ⁵ or more and a loss elastic modulus G ″ [Pa] at 180 ° C. of 1.0 ×. was such that the 10 ⁵ or more. This improves the dye diffusible in the dye-receiving layer, in a high speed printing condition is 0.7~2.0ms / line, transfer sensitivity of the dye, the transfer efficiency high, and The constituent resin of the dye receiving layer is not fluidized by heat during printing, the printed material is not blurred, the receiving layer surface is not roughened, and abnormal transfer in printing can be prevented.

The thermal transfer recording method of the present invention includes a thermal transfer sheet in which a dye layer containing a heat transferable dye and a binder is provided on a base material, and a thermal transfer image receiving sheet in which a sublimation dye receiving layer is formed on the base material sheet. In the thermal transfer recording method for forming an image on the receiving layer by heating according to image information and transferring the dye to heat, the thermal transfer recording speed is 0.7 to 2.0 ms / line. And the binder resin constituting the dye-receiving layer of the thermal transfer image-receiving sheet to be used has a storage elastic modulus G ′ [Pa] of dynamic viscoelasticity data at 180 ° C. of 1.0 × 10 ⁵ or more and at 180 ° C. The loss elastic modulus G ″ [Pa] was set to 1.0 × 10 ⁵ or more. With this, yellow, magenta, and cyan in this order under high-speed thermal transfer recording conditions of 0.7 to 2.0 ms / line. , Each dye When a black thermal transfer image was formed by superimposing the three colors of the dye from the material layer, it was possible to prevent fading of the printed matter and to obtain a thermal transfer image of a normal black hue.

Hereinafter, each layer constituting the thermal transfer image receiving sheet of the present invention will be described in detail.
(Substrate sheet)
As the substrate sheet in the thermal transfer image-receiving sheet of the present invention, paper, plastic film or the like can be used. As the paper, any of various kinds of single paper or processed paper can be used. For example, high-quality paper, coated paper, art paper In addition to cast-coated paper, paperboard, etc., impregnated paper such as resin emulsion or synthetic rubber latex, synthetic resin internal paper, and the like can be used. For synthetic paper, polystyrene synthetic paper, polyolefin synthetic paper, etc. can be used favorably. .

  For plastic films, polyolefin resin films such as polypropylene, polycarbonate films, polyethylene naphthalate films, polyester resin films such as polyethylene terephthalate films, rigid polyvinyl chloride films, polystyrene films, polyamide films, polyacrylonitrile films, polymethacrylates A film, a polyether ether ketone film, a polyether sulfone film, a polyarylate film, or the like can be used. In these plastic films, not only a transparent film but also a white opaque film formed by adding a white pigment, a filler or the like, or a foamed film can be used. Each of these materials can be used alone, but may be used as a laminate in combination with other materials.

  A base material having transparency can be used as the base material sheet. In this case, a stretched polypropylene or polyethylene terephthalate film is preferably used in practice. Thereby, it can be used on an OHP projector, and in the case of a seal type, a material that can be transmitted without deteriorating the appearance of the surface of the object to be stuck is obtained. In this case, as a matter of course, it is desirable that the portion to which the thermal transfer image receiving sheet is adhered, such as the colorant receiving layer and the adhesive layer, has transparency.

  Moreover, the base material sheet which carried out the easy adhesion process on the surface and / or the back surface of said base material sheet can also be used. The thickness of the base sheet of the thermal transfer image-receiving sheet is usually about 3 to 300 μm. In the present invention, it is preferable to use a base sheet of 75 to 250 μm in consideration of mechanical suitability and the like. Moreover, when the adhesiveness of a base material sheet and the layer provided on it is scarce, it is preferable to perform the easily bonding process and a corona discharge process on the surface.

(Dye-receiving layer)
The sublimable dye-receiving layer in the thermal transfer image-receiving sheet of the present invention has a storage elastic modulus G ′ [Pa] of dynamic viscoelasticity data at 180 ° C. of 1.0 × 10 ⁵ or more and a loss elastic modulus G at 180 ° C. ″ It is composed mainly of a binder resin having [Pa] of 1.0 × 10 ⁵ or more. The above dynamic viscoelasticity data measuring method is manufactured by TA Instruments Japan as a measuring instrument. An ARES dynamic viscoelasticity measuring instrument is used under the following conditions: parallel plate 25 mmΦ, strain 1%, amplitude (frequency) 1 Hz, heating rate 2 ° C./min., And the temperature of the receiving layer binder resin composition from 30 ° C. It is carried out by raising the temperature to 200 ° C. In general, the storage elastic modulus G ′ is an elastic component, which is generated when a structure such as a coil vibration or an aggregate structure in a polymer is generated, The loss elastic modulus G ″ is a viscous component and is equivalent to a static shear stress. However, in the present invention, the values measured by the above ARES are shown. However, if the measuring instrument and method can be measured based on the same principle and conditions, the values measured by them are the same as the values measured by the ARES. And is not limited to the values measured by ARES.

When the dye receiving layer is composed of a resin material having a storage elastic modulus G ′ [Pa] of less than 1.0 × 10 ^{5 at} 180 ° C., the constituent resin of the dye receiving layer is printed under high-speed thermal transfer recording conditions. The receiving layer is easily taken on the side of the dye layer, and the printed material is easily blurred or roughened on the receiving layer surface. Even when the above-described loss elastic modulus G ″ [Pa] is composed of a resin material having a loss elastic modulus of less than 1.0 × 10 ^{5 at} 180 ° C., the constituent resin of the dye-receiving layer under high-speed thermal transfer recording conditions. Is fluidized by heat at the time of printing, and the receiving layer tends to be taken on the dye layer side, and the printed matter is likely to be blurred or roughened on the surface of the receiving layer.

The storage elastic modulus G ′ [Pa] at 180 ° C. of the receiving layer binder resin is 1.0 × 10 ⁵ or more, but the upper limit is about 1.0 × 10 ⁷ . However, when adjusting the coating solution of the receiving layer, it becomes impossible to dissolve the receiving layer binder resin in the solvent of the coating solution, or the adhesiveness with the base sheet is adversely affected after the receiving layer is coated and dried. As long as no harmful effects occur, the upper limit value is not particularly limited. Further, the loss elastic modulus G ″ [Pa] at 180 ° C. of the receiving layer binder resin is 1.0 × 10 ⁵ or more, but the upper limit is about 1.0 × 10 ⁷ . However, as described above, the upper limit value is not particularly limited as long as no harmful effects occur.

  The storage elastic modulus G ′ [Pa] of the dynamic viscoelasticity data at 180 ° C. and the loss elastic modulus G ″ [Pa] at 180 ° C. are within the ranges specified above. A vinyl-vinyl acetate copolymer resin can be preferably used, and as the vinyl chloride-vinyl acetate copolymer resin, the copolymerization ratio of vinyl chloride and vinyl acetate is in the range of vinyl chloride-vinyl acetate = 95/5 to 50/50. The molecular weight of the vinyl chloride-vinyl acetate copolymer resin used in the present invention is several thousand to several hundreds of thousands in terms of number average molecular weight, in particular, vinyl chloride-vinyl acetate copolymer. When the number average molecular weight of the resin is 35000 or more and 50000 or less, a receiving layer is formed on the dye layer side, a print is blurred or received under high-speed thermal transfer recording conditions. The surface of the layer is not roughened, and the glass transition temperature of the vinyl chloride-vinyl acetate copolymer resin used is about 70 to 90 ° C. Particularly, the vinyl chloride-vinyl acetate copolymer is used. If the glass transition temperature of the polymer resin is 72 ° C. or higher and 80 ° C. or lower, the receiving layer is taken on the dye layer side, the print is blurred, or the surface of the receiving layer is rough under high-speed thermal transfer recording conditions. The glass transition temperatures described in the present invention are all measured based on JIS K7121-1987 using a generally known DSC (differential calorimeter). .

  In the dye receiving layer, a release component is contained in order to prevent a decrease in sensitivity at the time of fusing or printing with a thermal transfer sheet having a dye layer. Examples of the release component include silicone oil, phosphate ester-based interfacial lubricant, fluorine-based interfacial lubricant, etc., but epoxy modification, methylstyrene modification, polyether modification, amino modification, alkyl modification, carboxyl modification. It is preferable to use at least one selected from the group consisting of modified silicone oils such as alcohol-modified, fluorine-modified, olefin-modified and carbinol-modified from the viewpoint of releasability from the sublimable dye layer. As for the addition amount of the said mold release component, 0.5-30 mass parts is preferable with respect to 100 mass parts of receiving layer formation resin whole. When the range of the addition amount is not satisfied, problems such as fusion between the dye layer and the dye receiving layer of the thermal transfer sheet or a decrease in printing sensitivity may occur. By adding such a release component, the release component bleeds out on the surface of the receiving layer, and release properties are imparted on the surface of the receiving layer.

  A curing agent that reacts with a hydroxyl group can be added to the dye-receiving layer. The resin containing a hydroxyl group is a modified silicone oil resin. In the present invention, the curing agent that reacts with the hydroxyl group is not cured with the binder resin itself of the receiving layer. It relates to the binder resin of the receiving layer, and in the present invention, as indicated above, the range of storage elastic modulus G ′ [Pa] and loss elastic modulus G ″ [Pa] of the dynamic viscoelasticity data is defined. This is because the dynamic viscoelasticity data is determined by the characteristic value of the binder resin itself, and the dynamic viscoelasticity data is not changed by curing with the curing agent. One of the reasons is to ensure manufacturing stability in the coating of the layer.

  The curing agent that reacts with the hydroxyl group to be used is preferably an isocyanate compound or a chelate compound, particularly a non-yellowing type isocyanate compound. Specific examples include XDI, hydrogenated XDI, TMXDI, HDI and their respective attack / vuret bodies, oligomers, prepolymers, etc. In addition to this, the solvent of the receiving layer coating solution is dried. Any non-yellowing type is an isocyanate compound that undergoes a reaction in time. Specifically, what reacts within 100 minutes between 100-120 degreeC is preferable. A catalyst may be added as a reaction aid for the isocyanate compound, and any known catalyst can be used. A typical catalyst is a tin-based catalyst di-n-butyltin dilaurate (DBTDL). In addition, dibutyltin fatty acid salt catalysts, monobutyltin fatty acid salt catalysts, dioctyltin fatty acid salt catalysts, monooctyltin fatty acid salt catalysts, dimers thereof, and the like are effective, and tin per weight Since the reaction rate increases as the amount increases, the type, combination, and addition amount can be selected according to the isocyanate compound to be used. When a block type isocyanate compound is used, it is also effective to use a block dissociation catalyst.

  In addition, various additives can be added to the dye-receiving layer as necessary. Pigments and fillers such as titanium oxide, zinc oxide, kaolin, clay, calcium carbonate, and finely divided silica can be added for the purpose of improving the whiteness of the dye-receiving layer and further enhancing the sharpness of the transferred image. Further, known additives such as a plasticizer, an ultraviolet absorber, a light stabilizer, an antioxidant, a fluorescent brightening agent, and an antistatic agent can be added to the dye-receiving layer as necessary.

The binder resin listed above, the release agent listed above, and additives as necessary are added arbitrarily, and kneaded thoroughly with a solvent, diluent, etc. to produce a dye-receiving layer coating solution This is applied to the above-mentioned base sheet by a forming means such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, and dried to receive a dye. Configure the layer. Coating of an intermediate layer, a back layer, an easy-adhesion layer and the like provided as necessary, which will be described later, is also performed by the same method as the above-described dye-receiving layer forming means. Coating liquid thus formed is dye-receiving layer, usually, 0.5 to 50 g / m ² approximately in the dry state, preferably 2 to 10 g / m ^2.

(Middle layer)
An intermediate layer can be provided between the dye-receiving layer and the base sheet as necessary. Any material may be used for the intermediate layer depending on the purpose. For example, high whiteness can be obtained by using a resin obtained by adding various white pigments. Furthermore, a fluorescent whitening agent, an antistatic agent, etc. can be added as needed. Moreover, you may provide an intermediate | middle layer as needed in order to improve the adhesiveness between a base material sheet and a dye receiving layer. In order to improve the adhesion, a pretreatment for providing an intermediate layer such as a corona discharge treatment or an ozone treatment on the surface of the base sheet on the side to be formed with the dye receiving layer may be performed in advance.

As the intermediate layer, a layer obtained by curing a thermoplastic resin, a thermosetting resin, or a thermoplastic resin having a functional group by using various curing agents or other methods can be used. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, polyester, chlorinated polypropylene, modified polyolefin, urethane resin, acrylic resin, polycarbonate, ionomer, resin having a monofunctional and / or polyfunctional hydroxyl group-containing prepolymer cured with isocyanate or the like Etc. can be used. In order to impart functions such as whiteness and concealment to these resins, additives such as titanium oxide, calcium carbonate, barium sulfate and other known inorganic pigments, organic fillers, and fluorescent brighteners are added as necessary. Can be added. The coating thickness is preferably about 0.5 to 30 g / m ^{2 in a} dry state.

(Back layer)
A back layer can be provided on the surface of the base sheet opposite to the surface on which the dye-receiving layer is provided in order to improve the transportability of the thermal transfer image-receiving sheet and prevent curling. As a back layer with such functions, added to resins such as acrylic resin, cellulose resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl alcohol resin, polyamide resin, polystyrene resin, polyester resin, halogenated polymer As the agent, an acrylic filler, a polyamide filler, a fluorine filler, an organic filler such as polyethylene wax, and an inorganic filler such as silicon dioxide or metal oxide can be used. As the back layer, it is more preferable to use a resin obtained by curing the above resin with a curing agent. As the curing agent, generally known ones can be used, and among them, an isocyanate compound is preferable. The back layer resin reacts with an isocyanate compound or the like to form a urethane bond and is cured / three-dimensionalized, whereby the heat resistant storage stability and the solvent resistance are improved, and the adhesion to the substrate sheet is improved. As for the addition amount of a hardening | curing agent, 1 thru | or 2 is preferable with respect to the resin 1 reactive group equivalent. If it is less than 1, it takes a long time to complete the curing, and the heat resistance and solvent resistance deteriorate. On the other hand, when the value is larger than 2, problems such as a change with time after film formation or a short life of the coating solution for the back surface layer occur.

  Furthermore, you may add an organic filler or an inorganic filler as an additive in the said back surface layer. The function of these fillers improves the transportability of the thermal transfer image receiving sheet in the printer, and also improves the storage stability of the thermal transfer image receiving sheet, such as preventing blocking. Examples of the organic filler include acrylic filler, polyamide filler, fluorine filler, and polyethylene wax. Of these, polyamide filler is particularly preferred. Examples of the inorganic filler include silicon dioxide and metal oxide. The polyamide filler has a molecular weight of 100,000 to 900,000, is spherical, and preferably has an average particle diameter of 0.01 to 30 μm, particularly a molecular weight of 100,000 to 500,000 and an average particle diameter of 0.01 to 10 μm. Is more preferable. In addition, as a kind of polyamide filler, nylon (registered trademark) 12 filler is more preferable than nylon (registered trademark) 6 and nylon (registered trademark) 66 because it is excellent in water resistance and has no characteristic change due to water absorption.

An antistatic layer may be provided on the dye receiving layer surface or the back surface of the thermal transfer image receiving sheet, or on the outermost surface of both surfaces. Antistatic layer dissolves or disperses antistatic agent, fatty acid ester, sulfate ester, phosphate ester, amides, quaternary ammonium salt, betaines, amino acids, acrylic resin, ethylene oxide adduct, etc. in solvent It is possible to form by applying the applied one. The coating amount of the antistatic layer is preferably 0.001 to 0.1 g / m ² when dried.

(Thermal transfer recording method)
The thermal transfer recording method of the present invention includes a thermal transfer sheet in which a dye layer containing a heat transferable dye and a binder is provided on a base material, and a thermal transfer image receiving sheet in which a sublimation dye receiving layer is formed on the base material sheet. In the thermal transfer recording method for forming an image on the receiving layer by heating according to image information and transferring the dye to heat, the thermal transfer recording speed is 0.7 to 2.0 ms / line. And the binder resin constituting the dye-receiving layer of the thermal transfer image-receiving sheet to be used has a storage elastic modulus G ′ [Pa] of dynamic viscoelasticity data at 180 ° C. of 1.0 × 10 ⁵ or more and at 180 ° C. The loss elastic modulus G ″ [Pa] was set to 1.0 × 10 ⁵ or more.

  The thermal transfer image-receiving sheet used in the above-described thermal transfer recording method is as described above, and the thermal transfer sheet used in combination with the thermal transfer image-receiving sheet is each dye layer to which yellow, magenta, cyan, and optionally black are added. It has been used from the past. In the present invention, in particular, a thermal transfer sheet having three color layers of yellow, magenta, and cyan is used. The thermal transfer recording speed is 0.7 to 2.0 ms / line, that is, under high-speed thermal transfer recording conditions. When a black thermal transfer image is formed by superimposing three colors of dyes from each dye layer in the order of yellow, magenta, and cyan, it is possible to prevent fading on the printed matter, and a thermal transfer image of a normal hue of black is obtained. can get. The normal recording speed that is not a high-speed recording condition is generally about 2.1 to 5.0 ms / line.

  As a preferable recording condition applied in the thermal transfer recording method of the present invention, a thermal transfer sheet as a sample and a thermal transfer image receiving sheet are stacked between a thermal head and a platen roll so that the dye layer and the dye receiving layer are in contact with each other. The applied power of 0.04 to 0.16 W / dot is applied to the yellow, magenta, and cyan dye layers under the same conditions, and the three colors are superimposed in the order of yellow, magenta, and cyan. A black thermal transfer image is formed, and the reflection density of the black solid image is measured using a black filter to obtain 1.9 to 2.1 (maximum density).

Next, an Example and a comparative example are given and this invention is explained in full detail. In the text, “part” or “%” is based on mass unless otherwise specified. As a base sheet, apply an adhesive layer coating solution having the following composition on the surface opposite to the surface of the 39 μm-thick microvoided film of the fine void layer on which the dye-receiving layer described later is formed, and dry it. A coated paper (186.1 g / m ² ), which is a support provided with a layer on one side, was attached to the surface on which the back layer was not laminated. A primer layer coating solution having the following composition was applied to the surface to be coated with the receiving layer by wire bar coating so that the dry coating amount was 2.0 g / m ² and dried to form a primer layer. On the primer layer, a dye receiving layer coating solution having the following composition is applied by wire bar coating to a dry coating amount of 4.0 g / m ² and dried (110 ° C., 1 minute) to form a dye. A receiving layer was formed, and the thermal transfer image receiving sheet of Example 1 was produced.

<Adhesive layer coating solution>
Polyfunctional polyol (Takelac A-969V, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) 30 parts Isocyanate (Takenate A-5, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) 10 parts Ethyl acetate 60 parts

<Back layer formation conditions>
Using a coated paper with a basis weight of 157 g / m ² , after applying corona discharge treatment on one side, high-density polyethylene was applied as an underside grip layer on that side by a coating method (basis weight 29.1 g / m ² ). By doing so, a back layer was provided on the coated paper.

<Primer layer coating solution>
Polyester polyol (manufactured by Toyo Morton Co., Ltd., Adcoat) 15.0 parts Methyl ethyl ketone / toluene (mass ratio 2: 1) 85.0 parts

<Dye-receiving layer coating solution 1>
Vinyl chloride-vinyl acetate copolymer resin (manufactured by Solvain CN Nissin Chemical Industry Co., Ltd., storage elastic modulus G ′ [Pa] at 180 ° C. = 1.2 × 10 ⁵ , loss elastic modulus G ″ [Pa at 180 ° C.) ] = 2.0 × 10 ⁵ , vinyl chloride / acetate vinyl = 89/11, number average molecular weight ·· 42000, Tg ·· 75 ° C.) 20.0 parts Carboxyl-modified silicone (Shin-Etsu Chemical Co., Ltd., X-22-3701E) 1.0 part methyl ethyl ketone / toluene (mass ratio 1: 1) 79.0 parts

A thermal transfer image-receiving sheet of Example 2 was produced in the same manner as in Example 1 except that the dye-receiving layer had the following composition in the thermal transfer image-receiving sheet produced in Example 1.
<Dye-receiving layer coating solution 2>
Vinyl chloride-vinyl acetate copolymer resin (Solvine CH, manufactured by Nissin Chemical Industry Co., Ltd., storage elastic modulus G ′ [Pa] at 180 ° C. = 1.2 × 10 ⁵ , loss elastic modulus G ″ [Pa at 180 ° C. ] = 1.7 × 10 ⁵ , vinyl chloride / vinyl acetate = 86/14, number average molecular weight ·· 38000, Tg ·· 73 ° C.) 20.0 parts Carboxyl-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-3701E) 1.0 part methyl ethyl ketone / toluene (mass ratio 1: 1) 79.0 parts

(Comparative Example 1)
A thermal transfer image-receiving sheet of Comparative Example 1 was prepared in the same manner as in Example 1 except that the dye-receiving layer had the following composition in the thermal transfer image-receiving sheet prepared in Example 1.
<Dye-receiving layer coating solution 3>
Vinyl chloride-vinyl acetate copolymer resin (Solvain TA2, manufactured by Nissin Chemical Industry Co., Ltd., storage elastic modulus G ′ [Pa] at 180 ° C. = 1.0 × 10 ⁵ , loss elastic modulus G ″ [Pa at 180 ° C. ] = 8.2 × 10 ⁴ , vinyl chloride / vinyl acetate / others = 83/4/13, number average molecular weight ·· 33000, Tg ·· 70 ° C.) 20.0 parts Carboxyl-modified silicone (X--, manufactured by Shin-Etsu Chemical Co., Ltd.) 22-3701E) 1.0 part Methyl ethyl ketone / toluene (mass ratio 1: 1) 79.0 parts

(Comparative Example 2)
A thermal transfer image-receiving sheet of Comparative Example 2 was prepared in the same manner as in Example 1 except that the dye-receiving layer had the following composition in the thermal transfer image-receiving sheet prepared in Example 1.
<Dye-receiving layer coating solution 5>
Vinyl chloride-vinyl acetate copolymer resin (Solvine C, manufactured by Nissin Chemical Industry Co., Ltd., storage elastic modulus G ′ [Pa] at 180 ° C. = 6.7 × 10 ³ , loss elastic modulus G ″ [Pa ] = 1.4 × 10 ⁴ , PVC / acetate vinyl = 87/13, number average molecular weight ·· 31000, Tg ·· 70 ° C.) 20.0 parts Carboxyl-modified silicone (X-22-3701E, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part methyl ethyl ketone / toluene (mass ratio 1: 1) 79.0 parts

(Comparative Example 3)
A thermal transfer image-receiving sheet of Comparative Example 3 was prepared in the same manner as in Example 1 except that the dye-receiving layer had the following composition in the thermal transfer image-receiving sheet prepared in Example 1.
<Dye-receiving layer coating solution 6>
Vinyl chloride-vinyl acetate copolymer resin (Solvine CL, manufactured by Nissin Chemical Industry Co., Ltd., storage elastic modulus G ′ [Pa] at 180 ° C. = 3.9 × 10 ³ , loss elastic modulus G ″ [Pa ] = 7.4 × 10 ³ , polyvinyl chloride / vinyl acetate = 86/14, number average molecular weight 25000, Tg, 70 ° C. 20.0 parts Carboxyl-modified silicone (X-22-3701E manufactured by Shin-Etsu Chemical Co., Ltd.) 1.0 part methyl ethyl ketone / toluene (mass ratio 1: 1) 79.0 parts

<Scratch>
Using the thermal transfer image-receiving sheets of Examples and Comparative Examples prepared above, in combination with a dedicated thermal transfer sheet for CP9000 printer manufactured by Mitsubishi Electric Corporation, thermal transfer recording is performed under the following conditions, and under the following conditions: Evaluation of faintness was performed. However, the recording conditions were three types: high speed recording 1, high speed recording 2, and standard speed recording. (In other words, there are three types of recording conditions, high speed condition 1, high speed condition 2, and standard condition.)

(High-speed recording condition 1)
Thermal head; F-3598 (manufactured by Toshiba Hokuto Electronics Co., Ltd.)
Printing pressure: 5kg
Heating element average resistance value: 5186 (Ω)
Main scanning direction printing density; 300 dpi
Sub-scanning direction print density; 300 dpi
Applied power: 0.16 W / dot
Printing (recording) speed: 0.7 ms / line
Printing width: 150mm
Applied voltage: 29V
Printing start temperature; 28 (° C)

(High-speed recording condition 2)
Thermal head; F-3598 (manufactured by Toshiba Hokuto Electronics Co., Ltd.)
Printing pressure: 5kg
Heating element average resistance value: 5186 (Ω)
Main scanning direction printing density; 300 dpi
Sub-scanning direction print density; 300 dpi
Applied power: 0.16 W / dot
Printing (recording) speed: 2.0 ms / line
Printing width: 150mm
Applied voltage: 25V
Printing start temperature; 28 (° C)

(Standard speed recording conditions)
Thermal head; F-3598 (manufactured by Toshiba Hokuto Electronics Co., Ltd.)
Printing pressure: 5kg
Heating element average resistance value: 5186 (Ω)
Main scanning direction printing density; 300 dpi
Sub-scanning direction print density; 300 dpi
Applied power: 0.05 W / dot
Printing (recording) speed: 5.0 ms / line
Printing width: 150mm
Applied voltage: 15V
Printing start temperature; 28 (° C)

  However, the applied energy is applied to the yellow, magenta, and cyan dye layers under the same conditions to form a black solid heat transfer image by superimposing the three colors in the order of yellow, magenta, and cyan. In the printed matter using the thermal transfer image-receiving sheet of Examples 1 to 3, the reflection density of the solid image is 1.9 to 2.1 (maximum density) under high-speed recording conditions. In addition, in the printed matter using the thermal transfer image-receiving sheet of Comparative Examples 1 to 3, the printing speed is 1.9 to 2.1 (maximum density) under standard speed recording conditions.

(Evaluation of faintness)
Using the thermal transfer image-receiving sheets according to the above examples and comparative examples, the prints obtained by thermal transfer recording under the above-mentioned conditions are visually observed for the state of the thermal transfer image, and the degree of blurring, that is, the black solid For normal images, we examined differences in hue, solid image quality, and so on.

Evaluation was performed according to the following criteria.
○: The hue was black and there was no problem and the image quality was uniform.
X: A black portion having a strong redness in hue was generated, and the image quality was partially uneven.

The results of the above-described evaluation of faintness are as shown in Table 1 below.

From the above results, in the thermal transfer image receiving sheets prepared in Examples 1 to 3, the binder resin constituting the receiving layer has a storage elastic modulus G ′ [Pa] of dynamic viscoelasticity data at 180 ° C. of 1.0 × 10 ^5. The loss modulus of elasticity G ″ [Pa] at 180 ° C. is 1.0 × 10 ⁵ or more, and the printed matter obtained from the thermal transfer image-receiving sheet has a high-speed thermal transfer recording condition of 0.7 ms / line. Below, when a black thermal transfer image is formed by overlapping three colors of dyes from each dye layer in the order of yellow, magenta, and cyan, a black thermal transfer image is obtained, and there is no unevenness. It was of image quality (that is, no blurring of the printed material).

On the other hand, in the thermal transfer image receiving sheets prepared in Comparative Examples 1 to 3, the binder resin constituting the receiving layer has a storage elastic modulus G ′ [Pa] at 180 ° C. of less than 1.0 × 10 ⁵ and at 180 ° C. The loss elastic modulus G ″ [Pa] is less than 1.0 × 10 ⁵ , and a black thermal transfer image is obtained by superimposing three colors of dyes from each dye layer in the order of yellow, magenta, and cyan under high-speed printing conditions. When formed, the thermal transfer hue, which should be black, had a strong redness (less bluishness) and a highly uneven image quality.

Further, from the above results, when the thermal transfer image receiving sheets prepared in Examples 1 and 2 and Comparative Examples 1 to 3 are compared, vinyl chloride-vinyl acetate copolymer resin is used as the binder resin constituting the receiving layer. However, the vinyl chloride-vinyl acetate copolymer resin used in Examples 1 and 2 has a higher number average molecular weight than the vinyl chloride-vinyl acetate copolymer resin used in Comparative Examples 1-3. . In this way, when the binder resin constituting the receiving layer is a vinyl chloride-vinyl acetate copolymer resin, the number average molecular weight is high, so the heat resistance is improved, and matting on the surface of the printed material is possible even under high-speed printing conditions. It was possible to prevent faintness. However, the constraint under the condition that both the storage elastic modulus G ′ [Pa] at 180 ° C. and the loss elastic modulus G ″ [Pa] at 180 ° C. of the binder resin of the receiving layer to be used are 1.0 × 10 ⁵ or more. At.

Claims (5)

A thermal transfer image-receiving sheet in which a sublimable dye-receiving layer is formed on at least one surface of a substrate sheet, wherein the thermal transfer image-receiving sheet is used under high-speed thermal transfer recording conditions, and a binder resin constituting the receiving layer The storage elastic modulus G ′ [Pa] of the dynamic viscoelastic data at 180 ° C. is 1.0 × 10 ⁵ or more, and the loss elastic modulus G ″ [Pa] at 180 ° C. is 1.0 × 10 ⁵ or more. A thermal transfer image-receiving sheet characterized by being.   2. The thermal transfer image receiving sheet according to claim 1, wherein the binder resin in the receiving layer is a vinyl chloride-vinyl acetate copolymer resin.   The thermal transfer image-receiving sheet according to claim 1 or 2, wherein the vinyl chloride-vinyl acetate copolymer resin used as the binder resin in the receiving layer has a number average molecular weight of 35,000 or more.   4. The thermal transfer image receiving image according to claim 1, wherein the glass transition temperature of the vinyl chloride-vinyl acetate copolymer resin used as the binder resin in the receiving layer is 72 ° C. or higher. Sheet. A thermal transfer sheet provided with a dye layer containing a heat transferable dye and a binder on a base material and a thermal transfer image receiving sheet formed with a sublimation dye receiving layer on the base material sheet are superimposed, and according to image information In the thermal transfer recording method in which an image is formed on the receiving layer by heating and transferring the dye to heat, the thermal transfer recording speed is 0.7 to 2.0 ms / line, and A thermal transfer recording method, wherein thermal transfer recording is performed using the thermal transfer image-receiving sheet described in any of the above.