JP5674242B2 - Thermal transfer recording medium - Google Patents

Description

  The present invention relates to a thermal transfer recording medium used in a thermal transfer type printer, and a heat-resistant slipping layer is provided on one surface of a substrate, and an undercoat layer and a dye layer are provided on the other surface of the substrate. The present invention relates to sequentially formed thermal transfer recording media.

  In general, a thermal transfer recording medium is an ink ribbon called a thermal ribbon, which is used in a thermal transfer type printer, and has a thermal transfer layer on one side of the substrate and heat resistance on the other side of the substrate. A slipping layer (back coat layer) is provided. Here, the heat-sensitive transfer layer is an ink layer, and the ink is sublimated (sublimation transfer method) or melted (melt transfer method) by heat generated in the thermal head of the printer, and transferred to the transfer target side. is there.

  Currently, among the thermal transfer systems, the sublimation transfer system can easily form full-color images with various functions of the printer, so digital camera self-prints, cards such as identification cards, amusement output, etc. Widely used. Along with the diversification of such applications, there is a growing demand for smaller size, higher speed, lower cost, and durability for the printed material obtained. In recent years, durability has been given to the printed material on the same side of the base sheet. 2. Description of the Related Art Thermal transfer recording media having a plurality of thermal transfer layers provided so as not to overlap protective layers and the like that have been widely used have become quite popular.

  Under such circumstances, with the diversification and widespread use of applications, there has been a problem that sufficient print density cannot be obtained with the conventional thermal transfer recording medium as the printing speed of the printer further increases. . In order to increase the transfer sensitivity, attempts have been made to improve the transfer sensitivity in printing by reducing the thickness of the thermal transfer recording medium. However, wrinkles are caused by heat, pressure, etc. during the manufacture of the thermal transfer recording medium or during printing. It has a problem that it occurs or in some cases breaks.

  In addition, attempts have been made to increase the printing density and transfer sensitivity in printing by increasing the dye / resin (Dye / Binder) ratio in the dye layer of the thermal transfer recording medium. In addition to being up, a part of the dye migrates to the heat-resistant slipping layer of the thermal transfer recording medium during the winding state in the manufacturing process (setback), and when the rewinding is performed, the migrated dye has another color. When the dye layer or the protective layer is re-transferred (backside back) and the contaminated layer is thermally transferred to the transfer target, the hue becomes different from the designated color, or so-called scumming occurs.

  Attempts have also been made to increase the energy at the time of image formation on the printer side, not on the thermal transfer recording medium side, but not only the power consumption increases, but also the life of the thermal head of the printer is shortened. And the transfer target are fused, and so-called abnormal transfer is likely to occur. On the other hand, when a large amount of a release agent is added to the dye layer or the transfer target in order to prevent abnormal transfer, blurring of the image or background staining may occur.

  In order to solve such a demand, several methods have been proposed. For example, Patent Document 1 proposes a thermal transfer sheet having an adhesive layer containing a polyvinylpyrrolidone resin and a modified polyvinylpyrrolidone resin between a base material and a dye layer.

  Patent Document 2 proposes a thermal transfer sheet having an adhesive layer composed of a thermoplastic resin of polyvinyl pyrrolidone resin or polyvinyl alcohol resin and colloidal inorganic pigment ultrafine particles between a substrate and a dye layer.

JP-A-2005-231354 JP 2006-150956 A

  However, when a thermal transfer recording medium proposed in Patent Document 1 is used for printing with a recent high-speed printer using a sublimation transfer method, abnormal transfer is not confirmed, including those stored under high temperature and high humidity. However, the transfer sensitivity in the printing of things was low, and it did not reach a sufficient level.

  In addition, when the image was printed on the thermal transfer recording medium proposed in Patent Document 2, the transfer sensitivity in the print was high and reached a sufficient level. As a result, a thermal transfer recording medium capable of handling a high-speed printer that has high transfer sensitivity in printing and does not cause abnormal transfer even when stored under high temperature and high humidity has not been found.

  In view of the above problems, the present invention has high transfer sensitivity during high-speed printing, that is, it can reduce the amount of dye used in the dye layer, and can prevent abnormal transfer in printing even after storage at high temperature and high humidity. An object of the present invention is to provide a thermal transfer recording medium.

The thermal transfer recording medium according to the present invention is a thermal transfer recording medium in which a heat-resistant slipping layer is provided on one side of a substrate, and an undercoat layer and a dye layer are sequentially formed on the other side of the substrate. pull layer bracts least one aqueous titanium chelating agent or zirconyl chelating agent, a coating solution containing a polyvinyl alcohol resin and a water-soluble polymer as a main component, the coating is formed by drying, water-soluble polymer, polyvinyl It is characterized by being pyrrolidone .

Also, in the thermal transfer recording medium according to the present invention, the water-based titanium chelating agent or zirconyl chelating agent, based on the total solid content constituting the subbing layer is preferably contained 20 to 50 wt%.

In the thermal transfer recording medium according to the present invention, the coating amount of the undercoat layer after drying is preferably in the range of 0.10 g / m ^{2 to} 0.30 g / m ² .

  According to the present invention, the undercoat layer is formed by applying and drying a coating solution containing at least one of a water-based titanium chelating agent or a zirconyl chelating agent, a polyvinyl alcohol-based resin, and a water-soluble polymer as main components. High transfer sensitivity during high-speed printing, that is, high-density printing can be obtained without increasing the amount of dye used in the dye layer, and there is no abnormal transfer in printing even after storage at high temperature and high humidity. It becomes possible to provide a heat-sensitive transfer recording medium from which a sufficiently satisfactory print can be obtained.

1 is a side sectional view showing a configuration of a thermal transfer recording medium according to an embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the thermal transfer recording medium of one embodiment of the present invention is provided with a heat-resistant slipping layer 40 that imparts slidability with a thermal head on one surface of the substrate 10, and the other of the substrate 10. The undercoat layer 20 and the dye layer 30 containing at least one of a water-based titanium chelating agent or a zirconyl chelating agent, a polyvinyl alcohol-based resin, and a water-soluble polymer as main components are sequentially formed.

  Since the base material 10 is required to have heat resistance and strength not to be softened and deformed by heat pressure in thermal transfer, for example, polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, acetate, polycarbonate, polysulfone, polyimide, polyvinyl alcohol, aromatic A synthetic resin film such as polyamide, aramid, and polystyrene, and paper such as condenser paper and paraffin paper can be used alone or in combination. Among these, a polyethylene terephthalate film is preferable in view of physical properties, workability, cost, and the like.

  In addition, the thickness can be in the range of 2 μm to 50 μm in consideration of operability and workability, but in consideration of handling properties such as transfer suitability and workability, it is about 2 μm to 9 μm. Those are preferred.

  Moreover, in the base material 10, it is also possible to perform an adhesion treatment on the surface on which the heat resistant slipping layer 40 and / or the undercoat layer 20 is formed. As the adhesion treatment, known techniques such as corona treatment, flame treatment, ozone treatment, ultraviolet treatment, radiation treatment, roughening treatment, plasma treatment, primer treatment, etc. can be applied, and these treatments are used in combination. You can also In the present invention, it is effective to improve the adhesion between the substrate and the undercoat layer, and it is preferable to use a primer-treated polyethylene terephthalate film from the viewpoint of cost.

Next, the heat-resistant slipping layer 40 can be handled by a conventionally known layer. For example, a resin serving as a binder, a functional additive that imparts releasability and slipperiness, a filler, a curing agent, a solvent, and the like are blended. Thus, a coating solution for forming a heat resistant slipping layer can be prepared, coated and dried. The coating amount after drying of the heat resistant slipping layer 40 is suitably about 0.1 g / m ² or more and 2.0 g / m ² or less. Here, the coating amount after drying of the heat resistant slipping layer 40 means the amount of solid content remaining after applying and drying the coating solution for forming the heat resistant slipping layer, and after drying the undercoat layer 20 described later. Similarly, the coating amount of the dye layer 30 and the coating amount after the drying of the dye layer 30 indicate the solid amount remaining after the coating liquid is applied and dried.

  As an example of the heat resistant slipping layer, the binder resin may be polyvinyl butyral resin, polyvinyl acetoacetal resin, polyester resin, vinyl chloride-vinyl acetate copolymer, polyether resin, polybutadiene resin, acrylic polyol, polyurethane acrylate, polyester. Examples thereof include acrylate, polyether acrylate, epoxy acrylate, nitrocellulose resin, cellulose acetate resin, polyamide resin, polyimide resin, polyamideimide resin, and polycarbonate resin.

  Functional additives include natural waxes such as animal waxes and plant waxes, synthetic hydrocarbon waxes, aliphatic alcohols and acid waxes, fatty acid esters and glycerite waxes, synthetic ketone waxes, amine and amide waxes Synthetic waxes such as chlorinated hydrocarbon waxes and alpha-olefin waxes, higher fatty acid esters such as butyl stearate and ethyl oleate, sodium stearate, zinc stearate, calcium stearate, potassium stearate, magnesium stearate, etc. Surfactants such as higher fatty acid metal salts, long chain alkyl phosphate esters, polyoxyalkylene alkyl aryl ether phosphate esters or phosphate esters such as polyoxyalkylene alkyl ether phosphate esters, etc. Rukoto can.

  As fillers, talc, silica, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, kaolin, clay, silicone particles, polyethylene resin particles, polypropylene resin particles, polystyrene resin particles, polymethyl methacrylate resin particles, polyurethane resin particles, etc. Can be mentioned.

  Examples of the curing agent include isocyanates such as tolylene diisocyanate, triphenylmethane triisocyanate, tetramethylxylene diisocyanate, and derivatives thereof, but are not particularly limited.

  Next, the undercoat layer 20 is formed by applying and drying a coating solution containing at least one of a water-based titanium chelating agent or a zirconyl chelating agent, a polyvinyl alcohol-based resin, and a water-soluble polymer as main components.

  By forming such an undercoat layer, a high-density print can be obtained without increasing the amount of dye used in the dye layer, and there is no abnormal transfer in the print even after storage at high temperature and high humidity. A medium is obtained.

  Examples of the polyvinyl alcohol resin used for the undercoat layer include Kuraray Poval PVA-235 (manufactured by Kuraray Co., Ltd.), Kuraray Poval PVA-117 (manufactured by Kuraray Co., Ltd.), Kuraray Poval PVA-124 (manufactured by Kuraray Co., Ltd.), Gohsenol KH-20 ( Nippon Synthetic Chemical Co., Ltd.), Gohsenol N-300 (manufactured by Nippon Synthetic Chemical Co., Ltd.), and the like, Goosefimomer Z-200, which is an acetoacetylated polyvinyl alcohol having an acetoacetyl group and rich in reactivity. Z-320 (manufactured by Nippon Synthetic Chemical Co., Ltd.), water-based polyvinyl acetal esreck KX series (manufactured by Sekisui Chemical Co., Ltd.), eslek KW series (manufactured by Sekisui Chemical Co., Ltd.), etc., in which some alcohol groups of polyvinyl alcohol are acetal-modified. It is done.

By using a polyvinyl alcohol-based resin, a high-density print can be obtained without increasing the dye used in the dye layer. However, since the adhesion under high temperature and high humidity is extremely poor, it is difficult to use a polyvinyl alcohol resin alone.

  The water-based titanium chelating agent or zirconyl chelating agent has a property of reacting with a compound having a hydroxyl group, a carboxyl group or the like, and reacts with a polyvinyl alcohol-based resin or a water-soluble polymer to improve heat resistance and moisture resistance.

Specifically, examples of the water-based titanium chelating agent include ORGATICS TC-300 (manufactured by Matsumoto Fine Chemical Co., Ltd.), ORGATICS TC-310 (manufactured by Matsumoto Fine Chemical Co., Ltd.), ORGATICS TC-315 (manufactured by Matsumoto Fine Chemical Company), and zirconyl. As the chelating agent, commercially available products such as Olgatics ZB-126 (manufactured by Matsumoto Fine Chemical Co., Ltd.) can be suitably used. The content of the aqueous titanium chelating agent or zirconyl chelating agent is preferably 20 to 50 mass% with respect to the total solid content constituting the undercoat layer. If it is 20% or less, the storage stability under high temperature and high humidity is insufficient, and if it is 50% or more, sufficient print density cannot be obtained. Examples of water-soluble polymers are polyvinylpyrrolidone, starch, gelatin, methylcellulose, ethylcellulose, carboxymethylcellulose. And sodium alginate. Among these, polyvinylpyrrolidone is preferable because the adhesion between the base material after storage at high temperature and high humidity and the dye layer is relatively good.

Only polyvinyl alcohol resin and water-based titanium chelating agent or zirconyl chelating agent improve heat resistance and moisture resistance, but do not reach a practical level. However, by adding a water-soluble polymer, heat resistance and moisture resistance can reach practical levels without greatly deteriorating the print density.

Examples of polyvinyl pyrrolidone include homopolymers of vinyl pyrrolidone such as N-vinyl-2-pyrrolidone and N-vinyl-4-pyrrolidone, and copolymers thereof. Furthermore, modified polyvinyl pyrrolidone resin and the like can be mentioned. The modified polyvinyl pyrrolidone resin is a copolymer of an N-vinyl pyrrolidone monomer and another monomer. The form of copolymerization is not particularly limited, such as random copolymerization, block copolymerization, and graft copolymerization. The N-vinyl pyrrolidone monomer mentioned above refers to N-vinyl pyrrolidone (N-vinyl-2-pyrrolidone, N-vinyl-4-pyrrolidone, etc.) and derivatives thereof. Examples thereof include those having a substituent on the pyrrolidone ring such as vinyl-3-methylpyrrolidone, N-vinyl-5-methylpyrrolidone, N-vinyl-3,3,5-trimethylpyrrolidone, N-vinyl-3-benzylpyrrolidone. .
Examples of the monomer component copolymerized with the N-vinylpyrrolidone monomer include the following vinyl polymerizable monomers. For example, (meth) acrylic monomers such as (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, unsaturated carboxylic acids such as fumaric acid, maleic acid, itaconic acid, ethylene, Examples include propylene, vinyl chloride, vinyl acetate, vinyl alcohol, styrene, vinyl toluene, divinylbenzene, vinylidene chloride, ethylene tetrafluoride, and vinylidene fluoride.

The coating amount of the undercoat layer 20 after drying is not generally limited, but is preferably in the range of 0.10 g / m ² or more and 0.30 g / m ² or less. If it is less than 0.10 g / m ² , the transfer sensitivity at the time of high-speed printing is insufficient due to deterioration at the time of laminating the dye layer, and there is a concern that the adhesion to the substrate or the dye layer has a problem. On the other hand, if it exceeds 0.30 g / m ² , the sensitivity of the thermal transfer recording medium itself is affected, and there is a fear that the transfer sensitivity at the time of high-speed printing is insufficient.

Next, the dye layer 30 can be a conventionally known one. For example, the dye layer 30 is formed by preparing a coating solution for forming a dye layer by blending a heat-transferable dye, a binder, a solvent, and the like, and applying and drying the coating solution. The An appropriate coating amount of the dye layer 30 after drying is about 1.0 g / m ² . The dye layer can be composed of a single layer of one color, or a plurality of dye layers containing dyes having different hues can be repeatedly formed on the same surface of the same substrate in the surface order.

  The heat transferable dye in the dye layer is not particularly limited as long as it is a dye that melts, diffuses, or sublimates and transfers due to heat. For example, the yellow component includes solvent yellow 56, 16, 30, 93, 33, Disperse Yellow 201, 231, 33 and the like. Examples of the magenta component include C.I. I. Disperse thread 60, C.I. I. Disperse violet 26, C.I. I. Solvent Red 27, or C.I. I. Solvent Red 19 etc. can be mentioned. As the cyan component, C.I. I. Disperse Blue 354, C.I. I. Solvent Blue 63, C.I. I. Solvent Blue 36, or C.I. I. Disperse Blue 24 and the like. As a black ink dye, it is common to perform color matching by combining the above dyes.

  As the binder contained in the dye layer 30, any conventionally known resin binder can be used, and is not particularly limited, but cellulose-based materials such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, and cellulose acetate Examples thereof include vinyl resins such as resins, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl pyrrolidone, and polyacrylamide, polyester resins, styrene-acrylonitrile copolymer resins, and phenoxy resins.

  Here, the blending ratio of the dye and the binder in the dye layer 30 is preferably (dye) / (binder) = 10/100 to 300/100 on a mass basis. This is because when the ratio of (dye) / (binder) is less than 10/100, the amount of dye is too small and the color development sensitivity becomes insufficient, and a good thermal transfer image cannot be obtained, and this ratio is 300/100. If it exceeds the upper limit, the solubility of the dye in the binder is extremely lowered, so that when it becomes a thermal transfer recording medium, the storage stability is deteriorated and the dye is likely to precipitate. The dye layer may contain known additives such as an isocyanate compound, a silane coupling agent, a dispersant, a viscosity modifier, and a stabilizer as long as the performance is not impaired.

  The heat-resistant slip layer 40, the undercoat layer 20, and the dye layer 30 can be formed by applying and drying by a conventionally known application method. Examples of the application method include a gravure coating method, a screen printing method, a spray coating method, and a reverse roll coating method.

  Below, the material used for each Example and each comparative example of this invention is shown. In the text, “part” is based on mass unless otherwise specified.

<Preparation of substrate with heat-resistant slip layer>
As a base material, use a polyethylene terephthalate film with 4.5 μm single-sided easy-adhesion treatment, and apply a heat-resistant slipping layer coating solution of the following composition to the non-adhesive-treated surface by gravure coating method, After apply | coating so that it might be set to 1.0 g / m < ² > and drying at 100 degreeC for 1 minute, the base material with a heat-resistant slipping layer was obtained by aging for 1 week in a 40 degreeC environment.

<Heat resistant slipping layer coating solution>
Acrylic polyol resin 12.5 parts
Polyoxyalkylene alkyl ether / phosphate ester 2.5 parts
6.0 parts of talc
2,6-tolylene diisocyanate prepolymer 4.0 parts
Toluene 50.0 parts
Methyl ethyl ketone 20.0 parts
5.0 parts of ethyl acetate

Example 1
The undercoat layer coating solution-1 having the following composition was applied to the easy-adhesion treated surface of the substrate with a heat-resistant slip layer by a gravure coating method so that the coating amount after drying was 0.20 g / m ² . The undercoat layer was formed by drying at 100 ° C. for 2 minutes. Subsequently, a dye layer coating solution having the following composition is applied on the undercoat layer by a gravure coating method so that the coating amount after drying is 0.70 g / m ² and dried at 90 ° C. for 1 minute. Thus, a dye layer was formed, and the thermal transfer recording medium of Example 1 was obtained.

<Undercoat layer coating solution-1>
1.75 parts of polyvinyl alcohol
Titanium chelating agent 1.50 parts
1.75 parts of polyvinylpyrrolidone
57.0 parts of pure water
Isopropyl alcohol 38.0 parts

<Dye layer coating solution>
C. I. Solvent Blue 63 6.0 parts
Polyvinyl acetal resin 4.0 parts
45.0 parts of toluene
Methyl ethyl ketone 45.0 parts

(Example 2)
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer medium of Example 2 was obtained in the same manner as in Example 1 except that the undercoat layer was changed to the undercoat layer coating liquid-2 of the following composition. .

<Undercoat layer coating solution-2>
1.75 parts of polyvinyl alcohol
Zirconyl chelate 1.50 parts
1.75 parts of polyvinylpyrrolidone
57.0 parts of pure water
Isopropyl alcohol 38.0 parts

Example 3
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer medium of Example 3 was obtained in the same manner as in Example 1, except that the undercoat layer was changed to the undercoat layer coating solution-3 of the following composition. .

<Undercoat layer coating solution-3>
2.25 parts of polyvinyl alcohol
Titanium chelating agent 0.5 part
2.25 parts of polyvinylpyrrolidone
57.0 parts of pure water
Isopropyl alcohol 38.0 parts

Example 4
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer medium of Example 4 was obtained in the same manner as in Example 1, except that the undercoat layer was changed to the undercoat layer coating solution-4 of the following composition. .

<Undercoat layer coating solution-4>
Polyvinyl alcohol 1.1 parts
Titanium chelating agent 3.0 parts
1.1 parts of polyvinylpyrrolidone
57.0 parts of pure water
Isopropyl alcohol 38.0 parts

(Example 5)
In the heat-sensitive transfer recording medium produced in Example 1, the example was applied in the same manner as in Example 1 except that the undercoat layer was applied and dried so that the coating amount after drying was 0.05 g / m ^2. No. 5 thermal recording transfer medium was obtained.

(Example 6)
In the heat-sensitive transfer recording medium produced in Example 1, the Example was applied in the same manner as in Example 1 except that the undercoat layer was applied and dried so that the coating amount after drying was 0.35 g / m ^2. No. 6 thermal recording transfer medium was obtained.

(Comparative Example 1)
After forming the undercoat layer on the easy-adhesion treated surface of the substrate with a heat-resistant slipping layer, the same dye layer coating solution as in Example 1 is dried on the easy-adhesive treated surface by a gravure coating method. The coating amount was 0.70 g / m ² and dried at 90 ° C. for 1 minute to form a dye layer, whereby the thermal transfer recording medium of Comparative Example 1 was obtained.

(Comparative Example 2)
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer medium of Comparative Example 2 was obtained in the same manner as in Example 1 except that the undercoat layer was changed to the undercoat layer coating solution-5 of the following composition. .

<Undercoat layer coating solution-5>
Polyvinylpyrrolidone 5.0 parts
57.0 parts of pure water
Isopropyl alcohol 38.0 parts

(Comparative Example 3)
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer medium of Comparative Example 3 was obtained in the same manner as in Example 1 except that the undercoat layer was changed to the undercoat layer coating solution-6 of the following composition. .

<Undercoat layer coating solution-6>
Polyvinyl alcohol 5.0 parts
57.0 parts of pure water
Isopropyl alcohol 38.0 parts

(Comparative Example 4)
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer medium of Comparative Example 4 was obtained in the same manner as in Example 1 except that the undercoat layer was changed to the undercoat layer coating solution-7 of the following composition. .

<Undercoat layer coating solution-7>
Polyvinyl alcohol 2.5 parts
Polyvinylpyrrolidone 2.5 parts
76.0 parts of pure water
Isopropyl alcohol 19.0 parts

(Comparative Example 5)
In the thermal transfer recording medium produced in Example 1, the thermal recording transfer medium of Comparative Example 5 was obtained in the same manner as in Example 1 except that the undercoating layer was changed to the undercoating layer coating solution-8 of the following composition. .

<Undercoat layer coating solution-8>
Polyvinyl alcohol 3.5 parts
Titanium chelating agent 1.5 parts
76.0 parts of pure water
Isopropyl alcohol 19.0 parts

<Preparation of transfer object>
As a base material, a white foamed polyethylene terephthalate film of 188 μm is used, and an image-receiving layer coating solution having the following composition is applied to one surface thereof by a gravure coating method so that the coating amount after drying is 5.0 g / m ^2. By applying and drying, a transfer object for thermal transfer was produced.

<Image-receiving layer coating solution>
19.5 parts of vinyl chloride-vinyl acetate-vinyl alcohol copolymer
Amino-modified silicone oil 0.5 parts
Toluene 40.0 parts
Methyl ethyl ketone 40.0 parts

<Evaluation of adhesion of dye layer at room temperature>
With respect to the thermal transfer recording media of Examples 1 to 6 and Comparative Examples 1 to 5, a cellophane tape having a width of 18 mm and a length of 150 mm was pasted on the dye layer of the thermal transfer recording medium stored at room temperature, and immediately thereafter. Table 1 shows the results of evaluation by examining the presence or absence of the dye layer adhering to the cellophane tape when peeled off.
The evaluation was performed according to the following criteria.
○: Dye layer adhesion not recognized
Δ: Very little adhesion of dye layer is observed
X: Adhesion of the dye layer is recognized over the entire surface

<Evaluation of adhesion of dye layer after storage at high temperature and high humidity>
Regarding the thermal transfer recording media of Examples 1 to 6 and Comparative Examples 1 to 5, the thermal transfer recording media were stored for 72 hours and 84 hours at 40 ° C. and 90% RH, and then further stored for 24 hours at room temperature. Table 1 shows the results of evaluation by examining the presence or absence of the dye layer adhering to the cellophane tape when a cellophane tape having a width of 18 mm and a length of 150 mm was applied on the dye layer and then immediately peeled off. . The evaluation was performed according to the same standard as the above evaluation at normal temperature.

<Print evaluation>
Regarding the thermal transfer recording media of Examples 1 to 6 and Comparative Examples 1 to 5, the thermal transfer recording media stored at room temperature and after being stored in a 40 ° C. 90% RH environment for 72 hours and 84 hours, Table 2 shows the results of evaluation of the maximum reflection density and the presence or absence of abnormal transfer by performing solid printing with a thermal simulator using a thermal transfer recording medium and a transfer medium stored for 24 hours. Note that the maximum reflection density is a value obtained by measuring a printed portion where no shine is confirmed with X-Rite 528.
The printing conditions are as follows.
Printing environment: 23 ° C, 50% RH
Applied voltage: 29V
Line cycle: 0.7msec
Print density: main scanning 300 dpi sub-scanning 300 dpi

<Abnormal transcription evaluation>
The abnormal transcription was evaluated according to the following criteria.
○: Abnormal transfer to the transfer object is not observed
Δ: Very little abnormal transfer to the transfer medium
X: Abnormal transfer to the transfer object is observed on the entire surface

  From the results shown in Table 2, the thermal transfer recording media of Examples 1 to 6 having the undercoat layer are clearly faster than the thermal transfer recording medium of Comparative Example 1 having no undercoat layer. It was found that the transfer sensitivity during printing was high.

  In addition, from the results shown in Tables 1 and 2, the titanium chelating agent, polyvinyl alcohol and water-soluble resin satisfy all items of adhesion of the dye layer, abnormal transfer in printing, and printing density in storage at normal temperature and storage at high temperature and high humidity. Although the product was not obtained, it was found that the one using the mixture of the three types satisfied all of the adhesion of the dye layer, the abnormal transfer in the printing, and the printing density at room temperature storage and high temperature / high humidity storage. Among them, in Example 3 where the amount of the titanium chelating agent was small, it was found that the adhesion decreased under high temperature and high humidity. On the contrary, in Example 4 in which the amount of the titanium chelating agent was large, a result with no problem in adhesion under high temperature and high humidity was obtained, but it was found that the printing density was lowered.

Further, the thermal transfer recording medium of Example 5 has a coating amount of the undercoat layer of less than 0.10 g / m ^{2 as} compared with the thermal transfer recording medium of Example 4, so that after storage at a somewhat high temperature and high humidity. It was found that the adhesiveness of the lipstick was lowered, and that the effect of shine was somewhat lowered. In addition, the thermal transfer recording medium of Example 6 is less than the thermal transfer recording medium of Example 4 because the coating amount of the undercoat layer is more than 0.30 g / m ² , so that the effect of the transfer sensitivity is reduced. I found out.

  The thermal transfer recording medium obtained according to the embodiment of the present invention can be used in a sublimation transfer type printer, and in addition to the high speed and high functionality of the printer, various images can be easily formed in full color. It can be widely used for cards such as self-prints and identification cards, and amusement output.

  DESCRIPTION OF SYMBOLS 10 ... Base material, 20 ... Undercoat layer, 30 ... Dye layer, 40 ... Heat-resistant slipping layer.

Claims (3)

In a heat-sensitive transfer recording medium in which a heat-resistant slipping layer is provided on one surface of a substrate, and an undercoat layer and a dye layer are sequentially formed on the other surface of the substrate,
The undercoat layer is formed by applying and drying a coating solution containing at least one of a water-based titanium chelating agent or a zirconyl chelating agent, a polyvinyl alcohol-based resin and a water-soluble polymer as main components ,
A heat-sensitive transfer recording medium , wherein the water-soluble polymer is polyvinylpyrrolidone .   2. The thermal transfer recording medium according to claim 1, wherein the water-based titanium chelating agent or zirconyl chelating agent is contained in an amount of 20 to 50 mass% with respect to the total solid content constituting the undercoat layer. Thermal transfer recording medium according to claim 1 or 2 coating amount after drying of the undercoat layer, characterized in that it is in the range of 0.10 g / ^{m 2} or more 0.30 g / ^{m 2} or less.

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