JPH05246150A - Heat transfer image-receiving sheet - Google Patents

Abstract

PURPOSE:To provide a heat transfer image receiving sheet which provides a clear image with an enough density and exhibits excellent durabilities, especially excellent light-resistance, fingerprint-resistance, etc., of a formed image in a method for heat transfer using a sublimation dye. CONSTITUTION:A heat transfer image receiving sheet characterized by a sheet wherein a vinyl chloride copolymer resin contg. epoxy groups is incorporated in a dye accepting layer in the heat transfer image receiving sheet wherein the dye accepting layer is formed on at least one face of a base material sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer image-receiving sheet, and more specifically, it forms a recorded image excellent in color density, sharpness and various fastnesses, particularly durability such as light resistance, fingerprint resistance and heat resistance. It is intended to provide a thermal transfer image-receiving sheet that can be used.

[0002]

2. Description of the Related Art Conventionally, various thermal transfer methods are known. Among them, a sublimable dye is used as a recording agent, and a sublimable dye is used as a thermal transfer sheet by supporting it on a base material sheet such as polyester film. Transferable material that can be dyed, for example,
There has been proposed a method of forming various full-color images on an image receiving sheet having a dye receiving layer formed on paper, a plastic film or the like. In this case, the thermal head of the printer is used as the heating means, and a large number of three-color or four-color dots are transferred to the image-receiving sheet by heating for an extremely short time, and the full-color image of the original is formed by the multi-color dots. It is to be reproduced. The image formed in this way is extremely clear because the coloring material used is a dye and has excellent transparency, so the resulting image has excellent reproducibility of intermediate colors and gradation, and It is possible to form a high quality image which is similar to the image obtained by the offset printing or gravure printing and which is comparable to the full color photographic image.

[0003]

In order to effectively carry out the above-mentioned thermal transfer method, not only the structure of the thermal transfer sheet but also the structure of the image receiving sheet for forming an image are important. As a conventional technique of the thermal transfer image receiving sheet, for example, JP-A-57-169370 and 57-207 are known.
250, 60-25793, etc., polyester resins, vinyl resins such as polyvinyl chloride resins, polycarbonate resins, polyvinyl butyral resins, acrylic resins, cellulose resins, olefin resins, polystyrene resins. A resin in which a dye receiving layer is formed by using the above is disclosed. In the thermal transfer image-receiving sheet as described above, it is known that the dye-dyeing property of the dye-receiving layer and the various durability and storage stability of the image formed thereon are greatly changed depending on the resin forming the dye-receiving layer. There is. As a means for improving the dyeability of the dye to be transferred, a dye receiving layer is formed from a resin having good dyeability,
A plasticizer in the receiving layer may be included to improve the diffusibility of the dye at the time of thermal transfer. However, in the dye receiving layer made of a resin having a good dye-dyeing property, it is formed. Since the image bleeds during storage, the image storability is poor, and the fixing property of the dye is poor, there is a problem that the dye bleeds out to the surface and easily contaminates other articles that come into contact with the surface.

As a method for solving the above-mentioned problems of storability, stainability and the like, a resin in which the dyed dye does not easily migrate in the dye receiving layer may be selected. In this case, the dyeing of the dye is performed. There is a problem that the image is inferior and a high-density and high-definition image cannot be formed. Another major problem is the light resistance of the dyed dye and the discoloration of the image due to the effect of perspiration and sebum transferred to the image surface when the image area is touched by hand, and the receiving layer itself swells and cracks. However, there is a problem of anti-fingerprint property, and a migration property of a dye when it comes into contact with a substance containing a plasticizer such as an eraser or a soft vinyl chloride resin product, that is, a problem of plasticizer resistance. Examples of the resin that forms the receptive layer having excellent light resistance include polyvinyl acetal resins and polyvinyl chloride resins. Examples of the polyvinyl acetal resin include those disclosed in JP-A-57-207250 and JP-A-60- 25793, JP 61-11
293, JP-A-3-65391, JP-A-3
No. 162989 is disclosed. Further, the polyvinyl chloride resin is excellent in dyeing property of the dye, and therefore, it is disclosed in JP-A-59-224844 and JP-A-6-224844.
0-25793, JP 61-283595, JP 62-294595, JP 2-25.
Although disclosed in JP-A No. 890, JP-A-3-126589, etc., the polyvinyl acetal-based resin and the polyvinyl chloride-based resin disclosed therein are poor in plasticizer resistance and the like of the dye receiving layer to be formed. , The durability of the image is insufficient. Since polyvinyl chloride resin is relatively excellent in fingerprint resistance, it has been put to practical use because it is excellent in image formation (dyeing property) and image durability (light resistance, fingerprint resistance). In many cases. However, with regard to this polyvinyl chloride resin, the problem that the thermal stability of the ink in the state of being dissolved in a solvent is poor and the solution yellows occurs, and in the case of mass production, the quality of the image receiving sheet obtained There's a problem.
In particular, when a solution which is thermally deteriorated with time and turns yellow is used, there is a problem that the light resistance of an image on the obtained image-receiving sheet is significantly deteriorated. Therefore, an object of the present invention is to provide a clear image with sufficient density in a thermal transfer method using a sublimable dye, and the formed image has various fastnesses, particularly excellent light resistance, fingerprint resistance, etc. Is to provide a thermal transfer image-receiving sheet.

[0005]

The above object can be achieved by the present invention described below. That is, the present invention is a thermal transfer image-receiving sheet having a dye-receiving layer formed on at least one surface of a substrate sheet, wherein the dye-receiving layer contains a vinyl chloride copolymer resin containing an epoxy group. It is a characteristic thermal transfer image-receiving sheet.

[0006]

By using a vinyl chloride copolymer resin containing an epoxy group as the resin component of the ink for the dye receiving layer, the thermal stability of the ink is improved, and the light resistance and the light resistance of the formed image are improved. The durability such as fingerprint property is improved.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following preferred embodiments. The thermal transfer image-receiving sheet of the present invention comprises a dye receiving layer provided on at least one surface of a substrate sheet. The base sheet used in the present invention,
Synthetic paper (polyolefin-based, polystyrene-based, etc.), high-quality paper, art paper, coated paper, cast-coated paper, wallpaper, backing paper, synthetic resin or emulsion-impregnated paper, synthetic rubber latex-impregnated paper, synthetic resin internal-added paper, paperboard, etc. Films or sheets of various plastics such as, cellulose fiber paper, polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, polycarbonate, etc. can be used, and white pigments and fillers are added to these synthetic resins. A filmy white opaque film or a foamed foamed sheet can be used without any particular limitation. Further, a laminated body made of any combination of the above-mentioned substrate sheets can also be used. As an example of a typical laminated body, a synthetic paper of cellulose fiber paper and synthetic paper or cellulose fiber paper and plastic film or sheet can be mentioned. The thickness of these base material sheets may be arbitrary, for example, 10 to 30.
Generally, the thickness is about 0 μm. The substrate sheet as described above is preferably subjected to a primer treatment or a corona discharge treatment on the surface when the adhesion to the receiving layer formed on the surface is poor.

The receiving layer formed on the surface of the base sheet is for receiving the sublimable dye transferred from the thermal transfer sheet and maintaining the formed image. The epoxy group-containing vinyl chloride copolymer resin used in the present invention is an addition polymerizable monomer having vinyl chloride and a glycidyl group (for example, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, glycidyl vinyl sulfonate, glycidyl-p-vinyl). There are enzoate, vinyl cyclohexene monoxide, methallyl glycidyl ether, glycidyl allyl sulfonate, glycidyl methallyl sulfonate, glycidyl ethyl malate, methyl glycidyl itaconate, butadiene monooxide, 2-methyl-5,6-epoxyhexene, etc., Among them, glycidyl methacrylate and allyl glycidyl ether are preferable), and are generally obtained by copolymerization, for example, vinyl chloride-acetic acid vinyl acetate. Part of the copolymer resin is saponified, or a hydroxyl group-containing monomer such as hydroxyethyl (meth) acrylate is copolymerized and introduced to react the hydroxyl group with an epoxidizing agent such as epichlorohydrin to introduce an epoxy group. May be. The amount of the epoxy group-containing monomer unit in the epoxy group-containing vinyl chloride copolymer resin is preferably in the range of 0.5 to 50 mol%, and when the amount is less than this range, the thermal stability of the ink for forming a dye receiving layer is high. On the other hand, when the amount exceeds the above range, the dyeing property of the dye is insufficient.

If necessary, vinyl chloride and vinyl acetate can be copolymerized. In that case, the vinyl chloride / vinyl acetate copolymer molar ratio is 100/0 to 20.
However, if the amount of vinyl acetate exceeds the above range, the Tg of the vinyl chloride-vinyl acetate copolymer resin obtained will be low, and the dye dyed in the formed dye receiving layer will be It becomes easy to move, and the problem of blurring occurs in the image. Further, the epoxy group-containing vinyl chloride-based copolymer resin used in the present invention, maleic acid, maleic acid half ester, acrylic acid, methacrylic acid, itaconic acid or (meth) acrylamide, (meth) acrylonitrile, A monomer that produces a carboxyl group obtained by hydrolysis of (meth) acrylic acid ester, 2-
Improving the fingerprint resistance of the image formed on the receptor layer by copolymerizing a hydroxyl group-containing monomer such as hydroxy (meth) acrylate or by saponifying vinyl acetate units in the polymer to generate hydroxyl groups. Can be done. The degree of polymerization of the epoxy group-containing vinyl chloride copolymer resin used in the present invention as described above is 100 according to JIS K6721.
It is preferably about 1,000. Further, as the copolymerizable monomer, for example, fatty acid vinyl ester (vinyl acetate, vinyl propionate, vinyl butyrate, etc.), polymerizable monobasic acid [(meth) acrylic acid, (iso) crotonic acid, etc.],
(Meth) acrylic acid alkyl ester [(meth) acrylic acid methyl, ethyl, butyl, 2-ethylhexyl,
2-hydroxyethyl ester, etc.], polymerizable dibasic acid (maleic acid, fumaric acid, itaconic acid, etc.), mono- or dialkyl ester of polymerizable dibasic acid, anhydride of polymerizable dibasic acid (maleic anhydride, anhydrous Itaconic acid, etc.), vinylidene halide (vinylidene chloride, vinylidene fluoride, etc.), alkyl vinyl ether (methyl vinyl ether, isobutyl vinyl ether, lauryl vinyl ether, etc.), (meth) acrylonitrile, ethylene, propylene, vinylpyrrolidone, vinylpyridine, styrene, etc. Can be mentioned. Among these, fatty acid vinyl ester,
Vinyl acetate is particularly preferable.

In the present invention, the above epoxy group-containing vinyl chloride copolymer resin can be used alone or as a mixture, and other thermoplastic resins such as polyolefin resin such as polypropylene and polyvinyl chloride can be used. Halogenated polymers such as polyvinylidene chloride, polyvinyl acetate, polyacrylic esters, vinyl polymers such as polyvinyl acetal, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, ethylene and propylene Copolymer resins of olefins and other vinyl monomers, ionomers, cellulosic resins such as cellulose diacetate, and polycarbonates can also be used in combination.

The thermal transfer image-receiving sheet of the present invention comprises, on at least one surface of the above-mentioned substrate sheet, an epoxy group-containing vinyl chloride copolymer resin as described above and other necessary additives,
For example, a release agent, a cross-linking agent, a curing agent, a catalyst, a thermal release agent, an ultraviolet absorber, an antioxidant, a light stabilizer and the like added,
A dye dissolved in a suitable organic solvent or dispersed in an organic solvent or water is applied and dried by a forming means such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, and the like to obtain a dye. It is obtained by forming a receiving layer. In forming the above-mentioned receiving layer, pigments and fillers such as titanium oxide, zinc oxide, kaolin clay, calcium carbonate, fine powder silica and the like are used for the purpose of improving the whiteness of the receiving layer and further enhancing the sharpness of the transferred image. It can be added. The dye-receptive layer formed as described above may have any thickness, but generally has a thickness of 1 to 50 μm. Further, such a dye receiving layer is preferably a continuous coating, but it may be formed as a discontinuous coating by using a resin emulsion or resin dispersion.

Further, the thermal transfer image-receiving sheet of the present invention can be applied to various applications such as cards capable of thermal transfer recording and transmission type document preparation sheets by appropriately selecting a substrate sheet. Furthermore, the thermal transfer image-receiving sheet of the present invention can be provided with a cushion layer between the base sheet and the receiving layer if necessary, and by providing such a cushion layer, there is little noise during printing and image information can be dealt with. The recorded image can be transferred and recorded with good reproducibility. The thermal transfer sheet used when performing thermal transfer using the thermal transfer image-receiving sheet of the present invention as described above is a paper or polyester film provided with a dye layer containing a sublimable dye, and a conventionally known thermal transfer sheet is Both can be used as they are in the present invention. Further, as the means for applying the heat energy at the time of thermal transfer, any conventionally known applying means can be used, for example,
By controlling the recording time with a recording device such as a thermal printer (for example, a video printer VY-100 manufactured by Hitachi, Ltd.), 5 to 100 mJ / m
The intended purpose can be sufficiently achieved by applying thermal energy of about m ² .

[0013]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, “part” or “%” is based on weight unless otherwise specified. Examples 1 to 11 Synthetic paper as a base sheet (manufactured by Oji Yuka, thickness 110 μm
m) was coated on one side with a coating solution having the following composition at a rate of 5.0 g / m ² when dried, dried and cured to obtain a thermal transfer image-receiving sheet of the present invention. Composition of coating liquid: Resin of Table 1 15.0 parts Catalyst-curable silicone oil (X-621212, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.5 parts Platinum-based catalyst (Cat PL50T, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 part Methyl ethyl ketone / toluene (weight ratio 1/1) 83.5 parts

[0014]

[Table 1] VC: vinyl chloride unit VAc: vinyl acetate unit VOH: vinyl alcohol unit GMA: glycidyl methacrylate unit 2-HEMA: 2-hydroxyethyl methacrylate unit AA: acrylic acid unit MA: maleic acid unit AGE: allyl glycidyl ether unit It was determined by chlorine analysis and quantitative analysis of epoxy group by hydrochloric acid-pyridine method.

On the other hand, a dye layer-forming ink composition having the following composition was prepared, and a 6 μm-thick polyethylene terephthalate film having a back surface subjected to heat treatment had a dry coating amount of 1.0.
A thermal transfer sheet was obtained by applying and drying with a wire bar so as to obtain g / m ² . Ink composition: Indoaniline dye of the following structural formula 1.0 part Polyvinyl butyral resin (S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 10.0 parts Methyl ethyl ketone / toluene (weight ratio 1/1) 90.0 parts

[Chemical 1] The above-mentioned thermal transfer sheet and the above-mentioned thermal transfer image-receiving sheet of the present invention are superposed with their dye layers and dye receiving surfaces facing each other, and a head applied voltage of 11.0 is applied from the back surface of the thermal transfer sheet.
V, pulse width 16 msec. Dot density 6 dots / li
Recording was performed with a thermal head under the condition of ne, and the results shown in Table 2 below were obtained. In addition, the evaluation method of each performance shown in Table 2 was performed as follows.

(1) Light fastness test method The obtained image was measured at 100 KJ / m ² and 20 with a xenon fade odometer (Ci-35A, manufactured by Atlas).
The optical density was irradiated with 0 KJ / m ² (integrated light amount of 420 nm), the change in the optical density before and after the irradiation was measured with an optical densitometer (RD-918, manufactured by Macbeth Co.), and the residual ratio of the optical density was calculated by the following formula. .. Residual rate (%) = {[optical density after irradiation] / [optical density before irradiation]} × 100 ◎; residual rate is 90% or higher ○: residual rate is 80% or higher and lower than 90% Δ; residual rate is 70 % Or more and less than 80% x; residual rate is less than 70% (2) Fingerprint resistance evaluation method After fingerprints were imprinted on the surface of the printed matter and left at room temperature for 5 days,
The degree of discoloration and density change of the fingerprint imprinted portion was visually evaluated. A: Almost no difference between the fingerprint imprinted part and the non-imprinted part was recognized. B: Discoloration or change in density was observed. C: The imprinted part of the fingerprint was blank, and the fingerprint shape was clearly recognized. D: White spots occurred around the fingerprint imprinted portion, and at the same time, dye aggregation was observed.

Comparative Example 1 A polymer was synthesized with the composition shown in Comparative Example No. 1 in Table 1 above, and the procedure of Example 1 was repeated except that the polymer was used. Was evaluated. Comparative Example 2 A coating liquid having the same coating liquid composition as that of Comparative Example 1 (however, no platinum-based catalyst was used) was allowed to stand at 60 ° C. for 24 hours, after which a predetermined amount of platinum-based catalyst was added, and the others were compared. In the same manner as in Example 1, the image-receiving sheet was manufactured, the image was formed, and the image was evaluated. Comparative Example 3 A coating solution having the same coating solution composition as in Comparative Example 1 (however, no platinum-based catalyst was used) was allowed to stand at room temperature for 24 hours, and then a predetermined amount of platinum-based catalyst was added, and the others were compared. In the same manner as in Example 1, the image-receiving sheet was manufactured, the image was formed, and the image was evaluated. Comparative Example 4 An image receiving sheet was produced in the same manner as in Comparative Example 1 using the same coating solution as in Comparative Example 1, the image receiving sheet was left in an oven at 60 ° C. for 1 week, and then image formation and image evaluation were performed. I went.

Example 12 An image-receiving sheet was produced in the same manner as in Comparative Example 2 using the coating liquid of Example 1, and this image was formed and the image was evaluated. Example 13 An image receiving sheet was produced in the same manner as in Comparative Example 3 using the coating liquid of Example 1, and this image was formed and the image was evaluated. Example 14 An image-receiving sheet was produced in the same manner as in Comparative Example 4 using the coating liquid of Example 1, and this image was formed and the image was evaluated. Example 15 An image receiving sheet was produced in the same manner as in Comparative Example 2 using the coating liquid of Example 2, and the formation of this image and the evaluation of the image were performed. Example 16 An image receiving sheet was produced in the same manner as in Comparative Example 3 using the coating liquid of Example 2, and this image was formed and the image was evaluated. Example 17 An image-receiving sheet was produced using the coating liquid of Example 2 in the same manner as in Comparative Example 4, and this image was formed and the image was evaluated. Example 18 An image receiving sheet was produced in the same manner as in Comparative Example 2 using the coating liquid of Example 3, and this image was formed and the image was evaluated. Example 19 An image-receiving sheet was produced in the same manner as in Comparative Example 2 using the coating liquid of Example 4, and this image was formed and the image was evaluated. Example 20 An image receiving sheet was produced in the same manner as in Comparative Example 3 using the coating liquid of Example 5, and this image was formed and the image was evaluated.

Comparative Example 5 A polymer was synthesized with the composition shown in Comparative Example No. 2 in Table 1, and the same procedure as in Example 1 was carried out except that the polymer was used. Production of an image-receiving sheet, formation of an image and image formation (Incidentally, the ink was applied and dried immediately after the ink was produced, and printed immediately after the image-receiving sheet was produced to form an image.). Comparative Example 6 An image-receiving sheet was manufactured in the same manner as in Comparative Example 2 in Comparative Example 5, and this image was formed and evaluated. Comparative Example 7 In Comparative Example 5, an image receiving sheet was manufactured in the same manner as in Comparative Example 3, and the image formation and the image evaluation were performed. Comparative Example 8 In Comparative Example 5, an image-receiving sheet was produced in the same manner as in Comparative Example 4, and this image was formed and the image was evaluated.

[0020]

[Table 2] Table 2

[0021]

[Table 3] Continuation of Table 2

[0022]

[Effects] According to the present invention as described above, by using a vinyl chloride copolymer resin containing an epoxy group as a resin component of the ink for a dye receiving layer, the thermal stability of the ink is improved, The durability of the formed image such as light resistance and fingerprint resistance is improved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Hasegawa 1-1-1, Tanikaga-cho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd.

Claims (3)

[Claims] 1. A thermal transfer image-receiving sheet in which a dye receiving layer is formed on at least one surface of a base sheet, wherein the dye receiving layer contains a vinyl chloride copolymer resin containing an epoxy group. Thermal transfer image receiving sheet. 2. The thermal transfer image-receiving sheet according to claim 1, wherein the component constituting the epoxy group is an epoxy group-containing addition polymerizable monomer unit. 3. The thermal transfer image-receiving sheet according to claim 1, wherein the content of the monomer unit containing an epoxy group is 0.5 to 50 mol% of the vinyl chloride copolymer resin.