JP4121924B2 - Thermal transfer image receiving sheet - Google Patents

Description

  The present invention relates to an image-receiving sheet for thermal transfer recording, and more particularly to a thermal transfer image-receiving sheet that is used for sublimation transfer recording and has excellent antistatic performance, high image-receiving surface whiteness, and excellent processability in production. It is.

  Conventionally, various thermal transfer recording methods are known. Among them, in recent years, a thermal transfer sheet in which a thermal transfer layer containing a sublimable dye is formed on a support such as a polyester film is used as a thermal head or a laser. A sublimation transfer recording system in which an image is formed on a thermal transfer image receiving sheet by heating with a heating medium has attracted attention, and is used as an information recording means in various fields. According to such a sublimation transfer recording method, a full-color image can be formed in an extremely short time, and a high-quality image comparable to a full-color photographic image that is excellent in reproducibility and gradation of intermediate colors can be obtained. Can do.

  The image-receiving surface receives a sublimation dye transferred from the thermal transfer sheet, and retains the formed image, for example, a thermoplastic resin such as a saturated polyester resin, a vinyl chloride / vinyl acetate copolymer, a polycarbonate. An intermediate layer is provided between the receiving layer made of a resin or the like and, if necessary, between the base sheet and the receiving layer. As a function of the intermediate layer, for example, a layer imparting cushioning properties or a layer imparting antistatic properties may be provided when a highly rigid base sheet such as PET is used. The back side is coated with a composition in which an organic filler made of acrylic resin, fluorine resin, polyamide resin, etc., or inorganic filler such as silica is added to an acrylic resin binder to prevent curling and improve slipping properties. The back surface layer formed is provided as needed.

  The so-called standard type thermal transfer image-receiving sheet is used by viewing the image-receiving sheet with reflected light instead of transmitted light. PET, foamed PET, other plastic sheets, natural paper, synthetic paper, or a laminate of these is used. There are also various so-called seal-type thermal transfer image-receiving sheets in which a receiving layer is provided on one side of the base sheet, and an adhesive layer using a pressure sensitive adhesive or the like and a release paper are provided in order on the other side of the base sheet. It is used for various purposes. This seal type is used in which an image is formed on a receiving layer by thermal transfer, the release paper is peeled off and affixed to an arbitrary object.

  In many fields, thermal transfer image-receiving sheets are used, and anti-static performance is required when feeding or printing with a thermal transfer printer. The image receiving surface is required to have high whiteness. In contrast, in the conventional thermal transfer image-receiving sheet, an intermediate using an anionic emulsion resin, a metal oxide conductive agent such as tin oxide and a cationic fluorescent whitening agent between the base sheet and the receiving layer. A layer is provided. In this case, it is necessary to increase the amount of conductive agent such as tin oxide in order to obtain electrical conductivity. However, since tin oxide is a material having a relatively dark color tone, the whiteness of the intermediate layer containing the conductive material Will fall. In addition, metal oxides such as tin oxide may be very expensive, and when conductive titanium oxide is used instead of tin oxide, it is essentially white titanium oxide, but after the conductive treatment, gray blue And the whiteness of the image receiving paper is lowered.

Most of the hydrophilic resin constituting the intermediate layer of the thermal transfer image-receiving sheet is anionic, and when a cationic fluorescent whitening agent (about PH4) is used, it becomes ionically unstable, and the ink Agglomerated and problems occurred during coating. On the other hand, for example, in Patent Documents 1 and 2, in order to solve this problem, a water-soluble resin such as ionically neutral polyvinyl alcohol is added to achieve an ionically stable state, which causes a coating defect. Has solved. However, this decreases the whiteness, and the effect of the fluorescent brightener cannot be sufficiently obtained.
JP-A-8-118824 Japanese Patent Laid-Open No. 10-44628

  Therefore, an object of the present invention is to provide a thermal transfer image-receiving sheet that is excellent in stable antistatic performance, has a high whiteness on the image-receiving surface, is stable, and does not agglomerate the coating solution and has excellent coating suitability. .

Accordingly, in order to solve the above problems, as the invention according to claim 1, in the thermal transfer image receiving sheet in which the intermediate layer and the dye receiving layer are laminated in this order on at least one surface of the base sheet, the intermediate layer There are contained emulsion, hydrophilic resin and a fluorescent whitening agent and a conductive agent, conductive agent Ri synthetic layered silicate der, and in fluorescent whitening agent and basic water-soluble fluorescent whitening agent nitrous Rukoto was characterized.

In the thermal transfer image-receiving sheet of the present invention, an intermediate layer and a dye-receiving layer are laminated in this order on at least one surface of the base sheet, and a hydrophilic resin that can be emulsified on the intermediate layer, a fluorescent whitening agent, and a conductive agent. was contained, the conductive agent Ri synthetic layered silicate der, and the water-soluble fluorescent whitening agent der Rukoto of the fluorescent brightening agent is basic, resulting thermal transfer image-receiving sheet which is excellent in stable antistatic performance It is done. In addition, by using a basic water-soluble fluorescent whitening agent as the fluorescent whitening agent, the synthetic layered silicate of the conductive agent is stabilized in the solution of the basic intermediate layer, so that the solution does not aggregate and is suitable for coating. It will be excellent. Conventionally, water-soluble resins have been added in order to solve problems during coating of the intermediate layer, but the necessity has disappeared, and the hydrophilic resin that can be emulsified can be selected as the resin for forming the intermediate layer. A thermal transfer image-receiving sheet that spreads and has high whiteness can be easily obtained.

Hereinafter, embodiments of the present invention will be described in detail. Each layer constituting the thermal transfer image receiving sheet of the present invention will be described.
(Substrate sheet)
It is desirable that the base sheet has a role of holding the receiving layer and the intermediate layer, and has mechanical characteristics that can withstand heat applied during image formation and that does not hinder handling. The material of such a base sheet is, for example, polyester, polyarylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivative, polyethylene, ethylene / vinyl acetate copolymer, polypropylene, polystyrene, acrylic, polyvinyl chloride, Polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, polyether sulfone, tetrafluoroethylene / perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene / ethylene, tetrafluoroethylene / hexafluoropropylene Various plastic films or sheets such as polychlorotrifluoroethylene and polyvinylidene fluoride can be used. That.

  In particular, in the thermal transfer image-receiving sheet of the present invention, in order to enhance the whiteness on the image-receiving surface, it is preferable to use a substrate sheet having at least a whiteness on the side on which the receiving layer is provided. Therefore, a white film formed by adding a white pigment or filler to the resin constituting the plastic film mentioned above, or a foamed foam sheet, as well as condenser paper, glassine paper, sulfuric acid paper, synthetic paper (polyolefin type) , Polystyrene paper), fine paper, art paper, coated paper, cast coated paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, cellulose fiber paper, and the like. Moreover, the laminated body by arbitrary combinations of the said base material sheet can also be used. Representative examples include a laminate of cellulose fiber paper and synthetic paper, and cellulose fiber paper and a plastic film.

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. In the present invention, an antistatic treatment is carried out from the above base sheet or the above base sheet, and it is 1.0 × 10 ¹² Ω / □ or less in an environment of a temperature of 20 ° C. and a relative humidity of 50%. It is preferable to use a substrate sheet having a surface electrical resistivity of By using such a base sheet, troubles due to static electricity can be prevented before the thermal transfer image receiving sheet is produced. The thickness of these substrate sheets is usually about 30 to 300 μm. In the present invention, it is preferable to use a substrate sheet of 75 to 175 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 easy adhesion processing, such as a primer process, a corona discharge process, or a plasma process, on the surface.
(Middle layer)
The intermediate layer provided between the base sheet and the dye-receiving layer in the thermal transfer image-receiving sheet of the present invention contains an emulsifiable hydrophilic resin, a fluorescent brightening agent and a conductive agent, and the conductive agent is a synthetic layered silicic acid. It is characterized by being a salt.

  The hydrophilic resin used in the intermediate layer includes ethylene vinyl acetate copolymer, polyvinyl acetate, vinyl chloride, vinyl acetate copolymer, vinyl acetate (meth) acrylic copolymer, vinyl acetate veova copolymer, (meth) Examples include acrylic resins, styrene (meth) acrylic copolymers, vinyl resins such as styrene resins, polyamide resins such as melamine resins, urea resins, and benzoguanamine resins, polyester resins, polyurethane resins, and the like.

  The hydrophilic resin defined in the present invention is a complete dissolution (particle size: 0.01 μm or less), colloidal dispersion (0.01-0.1 μm), or emulsion (0.1) in a solvent mainly composed of water. ˜1 μm), or a resin that becomes a slurry (1 μm or more). Among these hydrophilic resins, particularly preferred are hexane, cyclohexane, acetone, methyl ethyl ketone, xylene, ethyl acetate, butyl acetate, toluene, methanol, ethanol, and alcohols such as IPA, as well as dissolution, It is a resin that does not even swell.

  Considering the adhesion performance, although it varies depending on the type of the base sheet and its surface treatment, urethane resins, acrylic-urethane resins, polyolefin resins, and vinyl resins are common and preferably used. In addition, when a thermoplastic resin having active hydrogen and a curing agent such as an isocyanate compound are used in combination, good adhesion can be obtained.

  As the optical brightener used in the intermediate layer, known ones such as stilbene, distilbene, benzoxazole, styryl-oxazole, pyrene-oxazole, distyryl-biphenyl, pyrazoline, benzimidazole, etc. Although usable, neutral to alkaline water-soluble ones are desirable. In particular, if an acidic (cationic) fluorescent whitening agent is used, the synthetic layered silicate and hydrophilic resin of the conductive agent will aggregate, the ink will become unstable, and the fluorescent whitening effect will not be obtained. It is. In particular, a fluorescent brightening agent having a hydrophilic group such as a sulfonic acid group is particularly preferable because it is difficult to migrate to the receiving layer.

  As a method of adding a fluorescent brightening agent, a method of adding it by dissolving it in water or the like according to the solubility characteristics of the binder resin to be added, a method of adding it by pulverizing and dispersing it with a ball mill or a colloid mill, a method of dissolving in a high boiling point solvent. For example, a method of mixing with a hydrophilic colloid solution and adding it as an oil-in-water dispersion, a method of impregnating in a polymer latex, and the like can be mentioned. The addition amount of the optical brightener is preferably 0.01 to 10% by mass with respect to the total resin of the intermediate layer in solid content.

  The synthetic layered silicate of the conductive agent used in the present invention is a synthetic product obtained by reacting sodium, magnesium and lithium salts with sodium silicate under appropriate conditions. The particle size is preferably 30 nm or less, and can be obtained, for example, under the trade name of Nippon Silica Kogyo Co., Ltd. Laponite S, JS and used in the present invention. In the case of a material derived from a natural mineral such as bentonite or hectorite having a similar structure, the glossiness of the image receiving paper which has no conductivity and can have a particle size of 300 to 550 nm is lowered. The synthetic layered silicate used in the present invention has poor stability in an acidic state (PH 6 or less), and aggregates when a cationic emulsion or a cationic fluorescent whitening agent is used, resulting in poor ink stability. A coating failure occurs. Therefore, in the coating liquid containing the synthetic layered silicate, the pH needs to be 7 or more in the state of the ink to be applied. Most of the resin emulsions are anionic (PH7 to 8.5), and the synthetic layered silicate can be used in combination with the neutral or basic fluorescent brightening agent.

  The amount added is a factor that affects the conductivity. Sufficient conductivity can be obtained with a small amount of addition, but from the viewpoint of dispersibility, stability and coating suitability, the amount of synthetic layered silicate added is about 1% to 500% (mass basis) with respect to the resin binder. However, if the amount is too small, stable conductivity cannot be obtained. If the amount is too large, the viscosity of the ink is increased, the coating suitability is decreased, and other adjacent materials including the base sheet are used. There may be a problem in that the adhesiveness with the other layer is lowered.

Therefore, the addition amount of the synthetic layered silicate is preferably 20% to 200% (mass basis), more preferably 50% to 200% (mass basis) with respect to the resin binder. As for the coating amount of the intermediate layer is one of the factors also influence the conductivity, it is possible to apply a range of 0.1g / m ² ~10g / m ² in a dry state, this since case the same problems as the added amount is generated, preferably ^{0.3g / m 2 ~5g / m 2} , more and most preferably ^{0.5g / m 2 ~3g / m 2} . In the intermediate layer, whiteness and conductivity are not impaired. Fatty acid ester, sulfuric acid ester, phosphoric acid ester, amides, quaternary ammonium salts, betaines, amino acids, acrylic resins, ethylene oxide adducts It is possible to add various antistatic agents such as. In addition to the fluorescent whitening agent, the synthetic layered silicate, and the antistatic agent, the intermediate layer includes a filler such as titanium oxide, zinc oxide, magnesium carbonate, calcium carbonate in order to impart whiteness. It is preferable to add.
(Dye-receiving layer)
The dye receiving layer formed on the intermediate layer is for receiving the sublimable dye transferred from the thermal transfer sheet and maintaining the formed thermal transfer image. Examples of the resin used for the receiving layer include halogenated polymers such as polyvinyl chloride and polyvinylidene chloride, polyvinyl acetate, ethylene / vinyl acetate copolymer, vinyl chloride / vinyl acetate copolymer, polyacrylic ester, Vinyl resins such as polystyrene and polystyrene / acrylic copolymers, acetal resins such as polyvinyl formal, polyvinyl butyral and polyvinyl acetoacetal, various polyester resins saturated or unsaturated, polycarbonate resins, cellulose resins such as cellulose acetate And polyamide resins such as polyolefin resins, urea resins, melamine resins, and benzoguanamine resins. These resins can be used alone or arbitrarily blended within a compatible range.

  Preferable mold release agents used by mixing with the resin include silicone oil, phosphate ester surfactants, fluorine surfactants, etc., but silicone oil is desirable. As the silicone oil, modified silicone oils such as epoxy modification, alkyl modification, amino modification, carboxyl modification, alcohol modification, fluorine modification, alkylaralkyl polyether modification, epoxy / polyether modification, and polyether modification are desirable.

One or more release agents are used. Also, multiple modified silicone oils such as reaction products of vinyl-modified silicone oil and hydrogen-modified silicone oil, reaction-cured products of amino-modified silicone oil and epoxy-modified silicone oil, or modified with active hydrogen. A reaction cured product of a silicone oil and a curing agent that reacts with active hydrogen is also used. Moreover, the addition amount of this release agent is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the dye-receiving layer forming resin. When the range of the addition amount is not satisfied, problems such as fusion of the thermal transfer film and the dye receiving layer or a decrease in printing sensitivity may occur. By adding such a releasing agent to the dye receiving layer, the releasing agent bleeds out on the surface of the receiving layer after transfer to form a releasing layer. The receptive layer is a dispersion obtained by dissolving the above-described resin with a necessary additive such as a mold release agent dissolved in an appropriate organic solvent or dispersed in an organic solvent or water. The body is formed by applying and drying the body by a forming means such as a gravure printing method, a screen printing method, or a reverse roll coating method using a gravure plate. The coating amount is 1.5 to 15 g / m ² , preferably 1.5 to 5.0 g / m ² . The thermal transfer image-receiving sheet of the present invention is characterized by the intermediate layer, and the receiving layer is not particularly limited. For the formation of the receiving layer, it is preferable to select a resin that is as colorless and highly transparent as possible.
(Conductive layer)
In the thermal transfer image-receiving sheet of the present invention, a conductive layer is formed on at least one side of the base sheet opposite to the side where the receiving layer is provided, and the conductive layer contains a conductive synthetic layered silicate. It is preferable. This conductive layer can be formed by the same material and manufacturing method as the above intermediate layer. The conductive layer formed on the side opposite to the side on which the receiving layer of the base sheet is provided is provided on the outermost surface on the back side of the base sheet, or between the base sheet and the back layer described below. It is also possible to provide it. However, when providing a conductive layer on the outermost surface on the back surface side of the base sheet, it is preferable to add various fillers used in the back layer described below to those described in the intermediate layer.
(Back layer)
A back layer can be provided on the surface of the base sheet opposite to the surface on which the 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, crosslinking is insufficient, and heat resistance and solvent resistance deteriorate. On the other hand, when the ratio is larger than 2, problems such as a change with the lapse of time or a short life of the coating solution for the back surface layer occur due to the curing agent remaining after the film formation.

  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. As for the type of polyamide-based filler, nylon 12 filler is more preferable than nylon 6 or nylon 66 because it is excellent in water resistance and has no characteristic change due to water absorption.

  The polyamide filler has a high melting point and is thermally stable, has good oil resistance and chemical resistance, and is difficult to be dyed with a dye. Further, when the molecular weight is 100,000 to 900,000, it hardly wears, has a self-lubricating property, has a low coefficient of friction, and hardly rubs a rubbing partner. A preferable average particle diameter is 0.1 to 30 μm. If the particle size is too small, the filler is hidden in the back surface layer, and there is a tendency that a sufficient function of slipperiness is not expressed. If the particle size is too large, the protrusion from the back surface layer becomes large. As a result, the coefficient of friction tends to be increased or fillers are lost, which is not preferable. The blending ratio of the filler to the resin of the back layer is preferably in the range of 0.01% by mass to 200% by mass. In the case of a thermal transfer image-receiving sheet for a reflection image, 1% by mass to 100% by mass is more preferable. When the blending ratio of the filler is less than 0.01% by mass, the slipperiness is insufficient, and there is a tendency to cause troubles such as paper jam when the printer is fed. On the other hand, if it exceeds 200% by mass, it is not preferable because it is too slippery and color misalignment or the like tends to occur in the printed image.

  In the thermal transfer image-receiving sheet of the present invention, in order to improve antistatic properties, the following antistatic agent can be kneaded into the receiving layer coating solution or the back layer coating solution. However, the receiving layer and the back surface layer are respectively located on the outermost surface of the thermal transfer image receiving sheet.

  Antistatic agents; fatty acid esters, sulfate esters, phosphate esters, amides, quaternary ammonium salts, betaines, amino acids, acrylic resins, ethylene oxide adducts, and the like. The addition amount of the antistatic agent is preferably 0.1 to 2.0% by mass with respect to the resin.

In the thermal transfer image receiving sheet of the present invention, in order to maintain high antistatic performance, an intermediate layer is provided between the base material sheet and the receiving layer, and the surface of the receiving layer is subjected to the above antistatic treatment, or the back surface of the base material sheet. A conductive layer is provided on at least one layer on the side, or the antistatic treatment is applied to the back layer surface. On either the receiving layer side or the back layer side, the surface electrical resistivity is preferably in the range of 1.0 × 10 ⁵ Ω / □ to 1.0 × 10 ¹⁴ Ω / □ in an environment of 23 ° C./60%. If the surface electrical resistivity is larger than 1.0 × 10 ¹⁴ Ω / □, the thermal transfer image-receiving sheets are stuck to each other due to electrostatic adhesion, which causes troubles during feeding or discharging in the thermal transfer printer.

  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.

As the substrate sheet, the thickness of 100μm white PET film: As (manufactured by Toray Industries, Inc. trade name Lumirror) with, becomes an intermediate layer coating solution 1 having the following composition on one surface thereof to dry 2.0 g / m ² The intermediate layer was formed by applying and drying with a gravure coater. Next, the receiving layer coating solution 1 having the following composition was coated and dried on the surface of the intermediate layer with a gravure coater so as to give 4.0 g / m ² when dried to form a receiving layer, and the thermal transfer image receiving of Example 1 of the present invention. A sheet was obtained.
<Intermediate layer coating solution 1>
Neo sticker 700 (urethane resin: Nikka Chemical) 100 parts

TCA-888 (Titanium oxide: Ishihara Sangyo) 37 parts

Laponite JS (conductive synthetic layered silicate: manufactured by Wilber Ellis) 40 parts Ubitex NFW Liqid (basic fluorescent whitening agent: Nippon Chibakaigi) 18 parts water 10 parts <receiving layer coating solution 1>
# 1000A (vinyl chloride / vinyl acetate copolymer: manufactured by Denki Kagaku Kogyo ■) 100 parts

X-22-3000T (silicone: manufactured by Shin-Etsu Chemical Co., Ltd.) 10 parts CAT-PL-50T (catalyst: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part methyl ethyl ketone 200 parts toluene 200 parts

Instead of the intermediate layer coating solution 1 in Example 1, an intermediate layer was formed using an intermediate layer coating solution 2 having the following composition, and the thermal transfer image receiving of Example 2 of the present invention was the same as in Example 1 except for the above. A sheet was obtained.
<Intermediate layer coating solution 2>
Polyester WR-905 (Polyester resin: Nippon Synthetic Chemical Co., Ltd.) 100 parts TCA-888 (Titanium oxide: Ishihara Sangyo Co., Ltd.) 37 parts Laponite JS (Conductive synthetic layered silicate: manufactured by Wilber Ellis) 40 Part Ubitex NFW Liquid (basic fluorescent whitening agent: Nippon Chibakaigi) 18 parts water 10 parts

In place of the intermediate layer coating solution 1 in Example 1, an intermediate layer was formed using an intermediate layer coating solution 3 having the following composition, and the thermal transfer image receiving of Example 3 of the present invention was performed in the same manner as in Example 1. A sheet was obtained.
<Intermediate layer coating solution 3>
Polyester WR-905 (Polyester resin: Nippon Synthetic Chemical Co., Ltd.) 100 parts TCA-888 (Titanium oxide: Ishihara Sangyo Co., Ltd.) 37 parts Laponite JS (Conductive synthetic layered silicate: manufactured by Wilber Ellis) 40 Part Ubitex CF Liquid (fluorescent whitening agent: Nippon Chibakaigi) 18 parts water 10 parts (Comparative Example 1)
Instead of the intermediate layer coating solution 1 in Example 1, an intermediate layer was formed using an intermediate layer coating solution 4 having the following composition, and the thermal transfer image receiving of Comparative Example 1 of the present invention was performed in the same manner as in Example 1. A sheet was obtained.
<Intermediate layer coating solution 4>
Polyester WR-905 (Polyester resin: Nippon Synthetic Chemical Co., Ltd.) 100 parts TCA-888 (Titanium oxide: Ishihara Sangyo Co., Ltd.) 37 parts Laponite JS (Conductive synthetic layered silicate: manufactured by Wilber Ellis) 40 Part Ubitex BAC (fluorescent brightener: Nippon Chibakaigi) 10 parts water 10 parts (Comparative Example 2)
In place of the intermediate layer coating solution 1 in Example 1, an intermediate layer was formed using an intermediate layer coating solution 5 having the following composition, and the thermal transfer image receiving of Comparative Example 2 of the present invention was performed in the same manner as in Example 1. A sheet was obtained.
<Intermediate layer coating solution 5>
Neo sticker 400 (urethane resin: Nikka Chemical) 100 parts

TCA-888 (Titanium oxide: Ishihara Sangyo) 37 parts

Laponite JS (conductive synthetic layered silicate: manufactured by Wilber Ellis) 40 parts Ubitex BAC (fluorescent whitening agent: Nippon Chibakaigi) 9 parts water 10 parts (Comparative Example 3)
Instead of the intermediate layer coating solution 1 in Example 1, an intermediate layer was formed using an intermediate layer coating solution 6 having the following composition, and the thermal transfer image receiving of Comparative Example 3 of the present invention was performed in the same manner as in Example 1 except that. A sheet was obtained.
<Intermediate layer coating solution 6>
Polyester WR-905 (Polyester resin: Nippon Synthetic Chemical Co., Ltd.) 100 parts TCA-888 (Titanium oxide: Ishihara Sangyo Co., Ltd.) 37 parts Laponite JS (Conductive synthetic layered silicate: manufactured by Wilber Ellis) 40 Part Ubitex AMS (fluorescent whitening agent: Nippon Chibakaigi) 10 parts water 10 parts (Comparative Example 4)
Instead of the intermediate layer coating solution 1 in Example 1, an intermediate layer was formed by using an intermediate layer coating solution 7 having the following composition, and the thermal transfer image receiving of Comparative Example 4 of the present invention was performed in the same manner as in Example 1. A sheet was obtained.
<Intermediate layer coating solution 7>
Polyester WR-905 (Polyester resin: Nippon Synthetic Chemical Co., Ltd.) 100 parts TCA-888 (Titanium oxide: Ishihara Sangyo Co., Ltd.) 37 parts Laponite JS (Conductive synthetic layered silicate: manufactured by Wilber Ellis) 40 Part Hackol HK (cationic fluorescent whitening agent: Nippon Kayaku Co., Ltd.) 40 parts Water 10 parts Image formation was carried out with an electric CP-2000 printer, and the transportability was examined in order to examine the antistatic performance. Further, the whiteness of the receiving layer side of the thermal transfer image-receiving sheet before image formation is measured. Furthermore, when manufacturing the thermal transfer image-receiving sheets of the above examples and comparative examples, the processing suitability (coating suitability) when applying the intermediate layer on the base sheet was examined.

The specific evaluation method is as follows.
(Transportability)
Ten thermal transfer image-receiving sheets are continuously conveyed to the printer and evaluated. Judgment criteria are as follows.
○: No abnormality.
X: A jam occurred in the printer. (The jam is caused by sticking of the thermal transfer image receiving sheets from the paper feeding unit, sticking of the thermal transfer image receiving sheet by the paper discharge unit, or the like.)
(Whiteness)
The reflection characteristics of the surface provided with the receiving layer of each thermal transfer image receiving sheet were measured with SPECTRO COLOR METER Model PF-10 manufactured by Nippon Denshoku Industries Co., Ltd. Judgment criteria are as follows.
○: Whiteness of 80% or more ×: Whiteness of less than 80% (processability)
The suitability for processing when the intermediate layer was applied on the base sheet with a gravure coater was evaluated according to the following criteria.
○: No abnormality.
X: The intermediate layer coating solution is agglomerated and cannot be applied with a stable coating amount on the substrate sheet, or the coated surface is non-uniform and the quality cannot be used as a thermal transfer image receiving sheet.
(Evaluation results)
The evaluation results are shown in Table 1 below.

Claims (1)

In a thermal transfer image-receiving sheet in which an intermediate layer and a dye-receiving layer are laminated in this order on at least one surface of a base sheet, the intermediate layer contains an emulsifiable hydrophilic resin, a fluorescent whitening agent, and a conductive agent. and which thermal transfer image-receiving sheet conductive agent Ri synthetic layered silicate der, and the fluorescent brightening agent, characterized in soluble fluorescent whitening agent der Rukoto basic.