JPH05155152A - Dye thermal transfer image-receiving sheet - Google Patents

Abstract

PURPOSE:To provide a dye thermal transfer image-receiving sheet, which is not fused with an ink sheet on printing and from which a distinct image having high density is obtained. CONSTITUTION:The title sheet is formed by curing a mixture obtained by blending an unsaturated organic compound curing the dye dyeing resin of an image- receiving layer formed onto a sheet-shaped base body by activating energy beams and a long-chain aliphatic compound having an acryloyl group by activation energy beams at the weight ratio of 100:5-30 by the irradiation of activating energy beams.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a dye thermal transfer image receiving sheet. More specifically, the present invention has no fusing with an ink sheet at the time of printing, has a high density image,
The present invention relates to a dye thermal transfer image receiving sheet which is clear and has excellent heat resistance and light resistance.

[0002]

2. Description of the Related Art In recent years, a thermal transfer type high-quality color hard copy, especially a dye thermal transfer type printer, has been rapidly developed. In the dye thermal transfer printer, the sublimable dye layers of three colors (yellow, magenta, and cyan) are heated by continuously controlling the heating energy of the thermal head, and the transfer amount of the dye of each color is changed to change the density. It enables the formation of full-color images with gradation.

In order to obtain a high-quality image on the dye thermal transfer image-receiving sheet, a dyeing resin for an image-receiving layer which has a high dye transfer rate, a large dyeing amount and a good storage stability is required. .. Heretofore, various polyester resins and vinyl chloride resins have been proposed as the resin for the image receiving layer, which has such a high transfer rate and a large dyeing amount and is excellent in preservability.

For example, as a resin for an image receiving layer, Japanese Patent Laid-Open No.
No. 7,107,885 discloses a saturated polyester resin, and JP-A No. 61-3796 discloses a sulfonated phthalic acid-modified polyester resin. Further, JP-A-63-7971 proposes to use a polyester resin composed of a phenyl group-containing polyol and a dicarboxylic acid as a resin for an image receiving layer. Furthermore, JP-A-59-223425 and JP-A-63-511.
No. 81 and Japanese Patent Laid-Open No. 2-67194 propose the use of vinyl chloride resin, but these are not always satisfactory.

As a dyeing mechanism of a dye in the dye thermal transfer system, as described in "Coloring Material, 59 (10), 1986 p607", an image receiving layer resin having a relatively low glass transition temperature is locally used. When heated, violent molecular motion occurs in the polymer chains in the amorphous region of that part, and it melts and softens to become a viscous liquid.The dye sublimated by the transfer operation jumps into this part, and upon cooling, the dye molecule becomes amorphous. It is considered that the resin is embedded in the area and the image receiving layer resin is dyed to form a colored image.

[0006] Such a thermal dye transfer system has the drawback that a large amount of energy is required for dye sublimation and the transfer speed is slow. Therefore, in order to improve the transfer speed, it has been attempted to lower the glass transition temperature of the resin used in the image receiving layer of the dye thermal transfer image receiving sheet. However, this causes a problem that the surface of the image receiving layer is roughened by heating during printing and the gloss of the transferred image is lowered. Further, at the time of printing, the image receiving layer is locally heated to 200 ° C. or more by heating with a thermal head or the like, so that the binder of the dye layer of the ink sheet and the resin for the image receiving layer are softened or melted, and the ink sheet and the image are There is a problem that the receiving layer is fused and cannot be peeled off.

In order to solve the above problem, Japanese Patent Laid-Open No. 62-1
No. 73,295 proposes that a coating liquid comprising a radiation-curable radical-polymerizable oligomer or monomer is applied to a sheet-like substrate and cured with an electron beam to form an image receiving layer. Since this method can obtain an image receiving layer made of a resin having a high cross-linking density, the problem of fusion between the receiving sheet and the ink sheet can be improved, but at the time of printing,
Since the image receiving layer does not melt and soften into a viscous liquid, the dye receiving ability of the image receiving layer is lowered, and it is difficult to obtain a high density image.

Other methods include a method of adding a releasing agent or a releasing agent to the image receiving layer, and a method of roughening the image receiving layer by adding a pigment to the image receiving layer (JP-A-57). -1
No. 07885), a method of using a crosslinkable resin in the image receiving layer (JP-A-58-215397), and a method of blending a small amount of a releasing agent in the ink sheet and the image receiving layer (JP-A-3-45389). ) Etc. have been proposed.

However, the method of adding a release agent and a release agent to the image receiving layer can prevent heat fusion with the ink sheet, but the image receiving layer and the release agent and the release agent are released after printing and stored. There have been problems such as bleeding of the image at that time, and the dye forming the image being transferred to another object and contaminated. Further, the method of adding a pigment to roughen the image receiving layer causes insufficient adhesion to the ink sheet, which causes a problem in uniformity of image density.

Further, the method using a crosslinkable resin is not preferable because the resin is hardened by the crosslinking and the dyeing property of the image receiving layer is poor, and when the resin is heated to crosslink it, the receiving paper is Due to the difference in shrinkage between the front and back sides, curling occurred, which caused problems in feeding and discharging paper to the printer. Further, the method using a release agent causes a problem of varying the friction coefficient. Above all, in order to stabilize the running property of the cut sheet, it is necessary to control the friction between the front and back of the paper and the friction between the paper and the ribbon within an appropriate range. Often made the running performance unstable.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, has a high receptive sensitivity and a high density of a dye image thermally transferred from an ink sheet, and has no heat fusion with the ink sheet. An object of the present invention is to provide a dye thermal transfer image receiving sheet having stable running properties.

[0012]

In the present invention, an image receiving layer is formed from an active energy ray-cured product, and at this time, an active energy ray-curable unsaturated organic compound is added as an active energy ray-curable precursor. The use of a mixture of a specific weight ratio of active energy ray-curable long-chain aliphatic compounds has succeeded in solving the above problems.

The dye thermal transfer image-receiving sheet of the present invention comprises a sheet-like substrate and an image-receiving layer containing a resin dyed with a dye formed on at least one surface of the sheet-like substrate. The resin dyed by the dye of the layer is composed of an unsaturated organic compound that is cured by active energy rays and an active energy ray cured product of a long chain aliphatic compound having an acryloyl group that is cured by active energy rays, and The amount of the chain aliphatic compound is in the range of 5 to 30 parts by weight with respect to 100 parts by weight of the unsaturated organic compound.

[0014]

The reason why the image receiving layer of the present invention does not cause fusion with the ink sheet is not clear, but the cured product of the long-chain aliphatic acryloyl compound contained in the image receiving layer resin is
It is presumed that the adhesiveness of the image receiving layer at high temperature is weakened to prevent fusion with the ink sheet. Further, the long-chain aliphatic acryloyl compound does not cause a problem such as image bleeding because the acryloyl group reacts by radical polymerization and is bonded to the unsaturated organic compound which is the dyeing resin.

The image-receiving layer of the dye thermal transfer image-receiving sheet of the present invention contains as a main component a cured product of an unsaturated organic compound which is cured by active energy rays and a long-chain aliphatic compound having an acryloyl group.

The present inventors have examined the fusion resistance of cured products of compounds which are cured by various active energy rays, and as a result, have found that acryloyl groups are present at both ends or one end of a long-chain aliphatic having 6 or more carbon atoms. It has been found that a cured product of active energy rays obtained from an acrylate compound having a is excellent in fusion resistance. Such a long-chain aliphatic acryloyl compound is, for example, decane, dodecane, tetradecane, hexadecane, eicosane, heneicosane, tetracosane, pentacosane, hexacosane, nonacosan, triacontane, hentriacontane, dotriacontane, tritriacontane, hexatria. It is an aliphatic acrylate compound having 6 or more carbon atoms, preferably 8 to 30 carbon atoms, such as contane, tetraacontane, doteriacontane, pentacontane, hexaacantane, heptacontane. Further, it may be branched into a chain of carbon atoms and may contain a cyclic structure, an ether bond or an ester bond.

The amount of the long-chain aliphatic compound compounded is 5 to 30 parts by weight with respect to 100 parts by weight of the unsaturated organic compound which is cured by active energy rays. If this amount is less than 5 parts by weight, heat fusion at the time of printing in the obtained image receiving sheet cannot be prevented, and if the amount is more than 30 parts by weight, the effect is saturated. ..

The following compounds can be used as the unsaturated organic compound which is hardened by the active energy rays used in the present invention. (1) An unsaturated urethane acrylate prepolymer which is a reaction product of a polyester polyol prepolymer, an isocyanate, and a (meth) acrylic acid ester compound having a hydroxyl group, at least ethylene glycol and neopentyl glycol as alcohol components of the polyester polyol. And an alkylene oxide adduct of bisphenol A and at least terephthalic acid and isophthalic acid as a dicarboxylic acid component (2) unsaturated acrylate compound having a rosin residue (3) polyacryloylalkyl phosphate ester (4) carvone Acid, polyol, acrylic acid reactant (5) Isocyanate, polyol, acrylic acid reactant (6) Epoxy compound and acrylic acid reactant (7) Epoxy compound, polyol, acrylic acid reactant

The image-receiving layer of the present invention may be blended with a low molecular weight organic compound such as a substituted phenol or terpene for the purpose of preventing oxidation, absorbing ultraviolet rays, sensitizing or the like. In general, white pigments used for improving the whiteness and opacity of paints, fluorescent dyes for adjusting the color tone of the image receiving layer, and dyes such as blue and violet can be added as required. The above white pigment, an ultraviolet absorber, an additive such as a cross-linking agent is conveniently mixed with the image-receiving layer resin-forming compound, which is the main component of the image-receiving layer, and applied. As another image receiving layer, it may be coated on or below the dyeing layer.

The dye thermal transfer image-receiving sheet of the present invention may be provided with a layer containing an antistatic agent on at least one surface of the sheet in order to prevent running troubles due to static electricity generated during running in a printer. A cationic hydrophilic polymer is advantageously used as the antistatic agent.

The sheet-like substrate used in the present invention includes high-quality paper, coated paper, polyester film, and
Various plastic films such as synthetic paper, which is a mono- or biaxially stretched film mainly composed of polyolefin and inorganic pigment, or laminated sheets made by combining them, polyolefin resin, extruded laminated paper mainly composed of pigment, etc. Can be used. The thickness of the sheet-like substrate used in the present invention is preferably 20 to 250 μm, and the basis weight is preferably ²⁰ to 250 g / m ² .

The thickness of the image receiving layer of the present invention is 1 to 20 g.
/ M², Preferably 4 to 10 g / m ²Is. This is thin
If it passes, the density and sensitivity of the image will decrease, limiting the coating accuracy.
Therefore, the uniformity of the image deteriorates. Also, if it is too thick
Not only is the effect saturated and uneconomical, but also the strength of the image receiving layer is high.
The degree decreases.

The coating composition for forming the image receiving layer of the present invention is cured by irradiation with active energy rays such as electron beams and ultraviolet rays. When an electron beam is used as the active energy beam, a curtain beam type electron beam accelerator that can obtain a large output at a relatively low cost can be used. In this curtain beam system, the accelerating voltage is 100 to 300 Kv and the absorbed dose is 0.5 to 10 Mrad. Further, the oxygen concentration in the atmosphere during irradiation is preferably 500 ppm or less, and when it is higher than 500 ppm, oxygen acts as a retarder for polymerization, and curing may be insufficient.

When ultraviolet rays are used as active energy rays, it is necessary to add 0.1 to 10% by weight of a photoinitiator to the total amount of the image receiving layer composition. Specific examples of the photoinitiator include a benzoin ether compound, a mixture of a benzophenone compound and an amine compound, a mixture of a thioxanthone compound and an amine compound, an acetophenone compound, a ketal compound and the like.

As a method for applying the coating composition for an image receiving layer to a sheet-like substrate, for example, a method using bar coating, air doctor coating, blade coating, squeeze coating, air knife coating, reverse roll coating, transfer coating, etc. may be used. is there. When irradiating the coating layer with active energy, the coating layer may be pressed against a molding material such as a cast drum or a film.

[0026]

EXAMPLES The present invention will be explained in more detail by the following examples, but the scope of the present invention is not limited thereby.

[0027] Example 1 (1) Synthesis of the image receiving layer unsaturated organic compound 1 (a) 60 mole% the dicarboxylic acid component Ingredient Quantity terephthalic acid (99.7 g) 40 mol% of isophthalic acid (66.5 g) (ii) diol component ingredients amount ethylene glycol 80 mol% (49.7 g) of neopentyl glycol 30 mol% (34.8 g) of bisphenol a 40 mol% (160.0 g) above a dicarboxylic acid component and a diol component, calcium acetate and 3 oxidation traces After heating with an antimony catalyst in a nitrogen atmosphere and raising the temperature to 150 ° C., this temperature is maintained for 1 hour to allow reaction, and then 0.1 mm.
Under reduced pressure of Hg or less, unreacted ethylene glycol was removed while performing polycondensation reaction at 250 ° C. for 3 hours to obtain a polyester polyol. Then, 1 mol of isophorone diisocyanate was added to 1 mol of the obtained polyester polyol.
Moles, 2-hydroxyethyl acrylate 2 moles,
Mixed solvent 16 of toluene / MEK = 4/1 as a diluent
A small amount of 00 g and 4-methoxyphenol as a polymerization inhibitor were added, and the mixture was gradually heated with stirring to raise the temperature to 75 ° C and reacted at 75 to 80 ° C for 2 hours. Furthermore, a small amount of stannous octylate was added as a urethane-forming catalyst to this mixture, and the mixture was reacted at 75 to 80 ° C. for 5 hours to produce unsaturated organic compound 1 for image receiving layer.

(2) Preparation of Coating 1 for Image Receiving Layer Component Weight Unsaturated organic compound for image receiving layer 100 parts Long-chain aliphatic acryloyl compound 5 parts (trademark: M-233, manufactured by Toagosei) Toluene / MEK = 400 parts of 4/1 mixed solvent

(3) Preparation of Dye Thermal Transfer Image Receiving Sheet Using 150 g / m ² of high-quality paper laminated with 30 μm of polyethylene on both sides as a base material, the coating material 1 for the image receiving layer is solidified on one side thereof. Minute application amount is 5g /
After coating so as to have a surface area of m ² and drying, the coating layer was irradiated with an electron beam so as to have an absorbed dose of 4 Mrad to cure the coating layer, and an image receiving layer was formed to obtain a receiving sheet. ..

A commercially available sublimation transfer color video printer (VP7100, manufactured by Fuji Film Co., Ltd.) was used for the obtained image receiving sheet.
Was used to print a step pattern, and the fusion with the ink sheet, the running property, and the image density were evaluated. In addition,
The evaluation method for each item is as follows. (1) Fusing with ink sheet: Binder block transfer of the ink sheet, which caused running trouble in the printer, was "defective", and block transfer was recognized but passed through the printer was "slightly". “Poor”, and those that passed through the printer without block transfer were defined as “good”. (2) Runnability: “Good” when 20 sheets of receiving sheets are printed and all sheets run in the printer without any trouble, “Slightly bad” when 1 to 5 sheet feeding or discharging errors occur, The case where 6 or more sheet feeding or discharging errors occurred was determined as "defective". (3) Image density: The maximum density of the printed image was measured with a Macbeth densitometer (Model No. RD-914, manufactured by Kollmorgen Corp.). The test results are shown in Table 1.

Example 2 An image receiving sheet was obtained in the same manner as in Example 1. However, the following image receiving layer coating material 2 was used as the image receiving layer coating material. Image-receiving layer coating 2 Ingredient wt image receiving layer unsaturated organic compound 100 parts long chain aliphatic acryloyl compound 30 parts (TM: M-233, manufactured by Toagosei) 400 parts Toluene / MEK = 4/1 mixed solvent of The test results are shown in Table 1.

Example 3 An image receiving sheet was obtained in the same manner as in Example 1. However, the following image-receiving layer coating material 3 was used as the image-receiving layer coating material. Image-receiving layer coating 3 Ingredient wt image receiving layer unsaturated organic compound 100 parts long chain aliphatic acryloyl compound 10 parts (Trademark: Photomer 4800, San Nopco Ltd.) Toluene / MEK = 4/1 mixed solvent 400 parts test results Is shown in Table 1.

Example 4 An image receiving sheet was obtained in the same manner as in Example 1. However, the following image-receiving layer coating material 4 was used as the image-receiving layer coating material. Image-receiving layer coating 4 Ingredient wt image receiving layer unsaturated organic compound 100 parts long chain aliphatic acryloyl compound 10 parts (Trademark: # 2000, SOMAR Ltd.) Toluene / MEK = 4/1 mixed solvent 400 parts test results Is shown in Table 1.

Example 5 An image receiving sheet was obtained in the same manner as in Example 1. However, the following image-receiving layer coating material 5 was used as the image-receiving layer coating material. Image-receiving layer coating 5 Ingredient wt rosin-modified urethane unsaturated organic compound 100 parts (Trademark: BS 102, manufactured by Arakawa Chemical) long chain aliphatic acryloyl compound 10 parts (TM: M-233, Toagosei Co., Ltd.) Toluene / MEK = 400 parts of 4/1 mixed solvent test results are shown in Table 1.

Comparative Example 1 An image receiving sheet was obtained in the same manner as in Example 1. However, the following image-receiving layer coating material 6 was used as the image-receiving layer coating material. Image-receiving layer coating 6 Ingredient wt image receiving layer unsaturated organic compound 100 parts long chain aliphatic acryloyl compound 3 parts (trade: M-233, manufactured by Toagosei) 400 parts Toluene / MEK = 4/1 mixed solvent of The test results are shown in Table 1.

Comparative Example 2 An image receiving sheet was obtained in the same manner as in Example 1. However, the following image-receiving layer coating material 7 was used as the image-receiving layer coating material. Image-receiving layer coating 7 Ingredient wt rosin-modified urethane unsaturated organic compound 100 parts (Trademark: BS 102, manufactured by Arakawa Chemical) long chain aliphatic acryloyl compound 3 parts (trade: M-233, Toagosei Co., Ltd.) Toluene / MEK = Table 1 shows the test results of 400 parts of 4/1 mixed solvent.

Comparative Example 3 An image receiving sheet was obtained in the same manner as in Example 1. However, the following image-receiving layer coating material 8 was used as the image-receiving layer coating material. A mixed solvent 400 parts test results of the image receiving layer coating 8 Ingredient wt image receiving layer unsaturated organic compound 100 parts of stearyl alcohol 30 parts Toluene / MEK = 4/1 shown in Table 1.

[0038]

[Table 1]

[0039]

Industrial Applicability According to the present invention, it is possible to produce a dye thermal transfer image receiving sheet which has a high sensitivity and a high density of a dye image, is not thermally fused to an ink sheet, and has a stable running property.

Claims (1)

[Claims] 1. A sheet-like substrate, and an image-receiving layer containing a resin formed on at least one surface of the sheet-like substrate and dyed with a dye. The image-receiving layer is dyed with the dye in the image-receiving layer. The resin is composed of an unsaturated organic compound curable by active energy rays and an active energy ray cured product of a long chain aliphatic compound having an acryloyl group curable by active energy rays, and the amount of the long chain aliphatic compound. Is in the range of 5 to 30 parts by weight with respect to 100 parts by weight of the unsaturated organic compound, a dye thermal transfer image receiving sheet.