JP3181972B2 - Thermal transfer image receiving sheet - Google Patents

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 particularly, to a recording image having excellent durability such as color density, sharpness and various fastnesses, particularly light fastness, fingerprint fastness and heat fastness. It is an object of the present invention to provide a heat 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 this is carried on a base sheet such as a polyester film to form a thermal transfer sheet. Dyeable transfer material, for example,
There have been proposed methods of forming various full-color images on an image receiving sheet having a dye receiving layer formed on paper, plastic film, or the like. In this case, a thermal head of a printer is used as a heating means, and a large number of color dots of three or four colors are transferred to the image receiving sheet by heating for a very short time, and a full-color image of the original is formed by the multicolor dots. That is to reproduce. The image formed in this way is very clear because the coloring material used is a dye, and is excellent in transparency, so that the obtained image is excellent in the reproducibility and gradation of intermediate colors. It is possible to form a high-quality image which is similar to an image by offset printing or gravure printing, and is comparable to a full-color photographic image.

[0003]

Problems to be Solved by the Invention In order to effectively carry out the above-described 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 equally important. As the prior art of the thermal transfer image receiving sheet, for example, JP-A-57-169370 and JP-A-57-207
Nos. 250, 60-25793 and the like, polyester resins, vinyl resins such as polyvinyl chloride resins, polycarbonate resins, polyvinyl butyral resins, acrylic resins, cellulose resins, olefin resins, and polystyrene resins. A resin in which a dye-receiving layer is formed by using such a method 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 greatly vary depending on the resin forming the dye-receiving layer. I have. Means for improving the dyeability of the transferred dye include forming a dye-receiving layer from a resin having good dyeability,
The diffusion of the dye at the time of thermal transfer may be improved by adding a plasticizer in the receiving layer, but in the dye receiving layer made of a resin having good dye-dyeing properties, the dye is formed. Since the image bleeds during storage, the storability of the image is poor, and the fixability of the dye is poor, there is a problem that the dye bleeds out to the surface and easily contaminates other articles in contact with the surface.

As a method for solving the above-mentioned problems such as storage stability and stainability, a resin which does not easily transfer dyed dye in the dye receiving layer may be selected. This is problematic in that a high-density and high-definition image cannot be formed. Another major problem is the light fastness of the dyed dye and the discoloration of the image due to sweat or sebum transferred to the image surface when touched with the image area, and the receiving layer itself swells or cracks. Problems, such as fingerprints, and the problem of migration of dyes upon 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 receptor layer having excellent light resistance include polyvinyl acetal-based resins and polyvinyl chloride-based resins. Examples of polyvinyl acetal-based resins include JP-A-57-207250 and JP-A-60-1985. 25793, JP-A-61-11
293, JP-A-3-65391, JP-A-3
It is disclosed in, for example, JP-A-162929. Further, polyvinyl chloride resins are known from JP-A-59-224844 and JP-A-
0-25793, JP-A-61-283595, JP-A-62-294595, JP-A-2-25
890 and JP-A-3-126589, but the polyvinyl acetal-based resins and polyvinyl chloride-based resins disclosed therein have poor dye-receiving layer plasticizer resistance and the like. And the durability of the image is insufficient. Polyvinyl chloride resins have been put to practical use because they are relatively excellent in fingerprint resistance and are excellent in image formation (dyeing) and image durability (light resistance and fingerprint resistance). Often. However, with respect to this polyvinyl chloride resin, the thermal stability of the ink is poor when dissolved in a solvent, causing a problem that the solution turns yellow, and in the case of mass production, the quality of the image receiving sheet obtained is reduced. There's a problem.
In particular, when a solution in which the solution is thermally deteriorated with time and yellowed is used, there is a problem that light fastness of an image on an obtained image receiving sheet is significantly deteriorated. Accordingly, an object of the present invention is to provide a clear image having a sufficient density in a thermal transfer method using a sublimable dye, and furthermore, the formed image has excellent various fastnesses, particularly excellent light fastness and fingerprint fastness. Is to provide a thermal transfer image receiving sheet showing

[0005]

The above object is achieved by the present invention described below. That is, the present invention provides a thermal transfer image-receiving sheet having a dye-receiving layer formed on at least one surface of a base sheet, wherein the dye-receiving layer contains an epoxy group- containing material.
Vinyl chloride copolymer resin containing 0.5 to 50 mol% of addition polymerizable monomer unit , catalyst-curable silicone oil
And a thermal transfer image receiving sheet formed of a platinum-based catalyst .

[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. Durability such as fingerprints is improved.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in more detail with reference to 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. As the base sheet used in the present invention,
Synthetic paper (polyolefin, polystyrene, 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 paper, paperboard, etc. Various types of plastic films or sheets, such as cellulose fiber paper, polyolefin, polyvinyl chloride, polyethylene terephthalate, polystyrene, polymethacrylate, and polycarbonate, can be used.Additionally, a white pigment or filler is added to these synthetic resins. A filmed white opaque film, a foamed foam sheet, or the like can be used, and is not particularly limited. Also, a laminate formed by any combination of the above base sheets can be used. Examples of typical laminates include synthetic paper of cellulose fiber paper and synthetic paper or cellulose fiber paper and plastic film or sheet. The thickness of these substrate sheets may be arbitrary, for example, 10 to 30
A thickness of about 0 μm is common. When the base sheet as described above has a poor adhesion to the receiving layer formed on the surface, it is preferable to subject the surface to a primer treatment or a corona discharge treatment.

[0008] The receptor layer formed on the surface of the substrate 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). Enzoate, vinylcyclohexene monoxide, methallyl glycidyl ether, glycidyl allyl sulfonate, glycidyl methallyl sulfonate, glycidyl ethyl malate, methyl glycidyl itaconate, butadiene monooxide, 2-methyl-5,6-epoxyhexene and the like, Among them, glycidyl methacrylate and allyl glycidyl ether are preferable). The epoxy group is introduced by reacting an epoxy resin such as epichlorohydrin with the hydroxyl group introduced by partially saponifying the copolymer resin or copolymerizing a hydroxyl group-containing monomer such as hydroxyethyl (meth) acrylate. You may. The amount of the epoxy group-containing monomer unit in the epoxy group-containing vinyl chloride copolymer resin is in the range occupying 0.5 to 50 mol% . If the amount is less than the above range, the thermal stability of the ink for forming a dye receiving layer is insufficient, while if 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 this case, the copolymerization molar ratio of vinyl chloride to vinyl acetate is 100/0 to 20.
/ 80, but when the amount of vinyl acetate exceeds the above range, the Tg of the obtained vinyl chloride-vinyl acetate copolymer-based resin becomes low, and the dye dyed on the formed dye receiving layer becomes It becomes easy to move, and the problem of blurring occurs in the image. In addition, the epoxy group-containing vinyl chloride copolymer resin used in the present invention may be prepared from maleic acid, maleic acid half ester, acrylic acid, methacrylic acid, itaconic acid, (meth) acrylamide, (meth) acrylonitrile, A monomer that produces a carboxyl group obtained by hydrolysis, such as (meth) acrylic acid ester;
It is possible to improve 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 a vinyl acetate unit in the polymer to generate a hydroxyl group. I can do it. 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 copolymerizable monomers, for example, fatty acid vinyl esters (vinyl acetate, vinyl propionate, vinyl butyrate, etc.), polymerizable monobasic acids [(meth) acrylic acid, (iso) crotonic acid, etc.],
(Meth) acrylic acid alkyl ester [methyl (meth) acrylic acid, ethyl, butyl, 2-ethylhexyl,
2-hydroxyethyl ester, etc.], polymerizable dibasic acids (maleic acid, fumaric acid, itaconic acid, etc.), mono- or dialkyl esters of polymerizable dibasic acids, and anhydrides of polymerizable dibasic acids (maleic anhydride, anhydride Itaconic acid, etc.), vinylidene halides (vinylidene chloride, vinylidene fluoride, etc.), alkyl vinyl ethers (methyl vinyl ether, isobutyl vinyl ether, lauryl vinyl ether, etc.), (meth) acrylonitrile, ethylene, propylene, vinylpyrrolidone, vinylpyridine, styrene, etc. No. Among these, fatty acid vinyl esters,
Particularly, vinyl acetate is preferable.

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

The thermal transfer image-receiving sheet according to the present invention comprises an epoxy group-containing vinyl chloride copolymer resin as described above and at least one other additive on at least one surface of the base sheet.
For example, a release agent, a cross-linking agent, a curing agent, a catalyst, a heat release agent, an ultraviolet absorber, an antioxidant, a light stabilizer and the like are added.
A dispersion dissolved in an appropriate organic solvent or dispersed in an organic solvent or water is coated 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 dried to form a dye. It is obtained by forming a receiving layer. In forming the receiving layer, a pigment or filler such as titanium oxide, zinc oxide, kaolin clay, calcium carbonate, and finely powdered silica is used for the purpose of improving the whiteness of the receiving layer to further enhance the sharpness of a transferred image. Can be added. The dye-receiving 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 may be formed as a discontinuous coating using a resin emulsion or a resin dispersion.

The thermal transfer image-receiving sheet of the present invention can be applied to various uses such as cards capable of thermal transfer recording and sheets for transmission type original production by appropriately selecting a base sheet. Further, 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. By providing such a cushion layer, noise during printing can be reduced and image information can be handled. The transferred 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 provided with a dye layer containing a sublimable dye on paper or polyester film. Any of them can be used as it is in the present invention. Further, as the means for applying thermal energy during 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, Video Printer VY-100 manufactured by Hitachi, Ltd.), 5 to 100 mJ / m
By applying thermal energy of about m ² , the intended purpose can be sufficiently achieved.

[0013]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, parts and% are based on weight unless otherwise specified. Examples 1 to 11 As a base sheet, synthetic paper (manufactured by Oji Yuka, thickness 110 μm)
m), a coating liquid having the following composition was applied on one surface of the coating with a wire bar 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. Coating liquid composition; resin in Table 1 15.0 parts Catalyst-curable silicone oil (X-62-1212, manufactured by Shin-Etsu Chemical) 1.5 parts Platinum-based catalyst (Cat PL50T, manufactured by Shin-Etsu Chemical) 0.1 part 83.5 parts of methyl ethyl ketone / toluene (weight ratio 1/1)

[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 groups by the hydrochloric acid-pyridine method.

On the other hand, an ink composition for forming a dye layer having the following composition was prepared, and a 6 μm-thick polyethylene terephthalate film having a heat-treated back surface was coated with a dry coating amount of 1.0%.
g / m ² was applied by a wire bar and dried to obtain a thermal transfer sheet. Ink composition: Indoaniline dye having the following structural formula : 1.0 part Polyvinyl butyral resin (ESLEK BX-1, manufactured by Sekisui Chemical) 10.0 parts Methyl ethyl ketone / toluene (weight ratio 1/1) 90.0 parts

Embedded image The above-mentioned thermal transfer sheet and the above-mentioned thermal transfer image-receiving sheet of the present invention are superposed on each other with the respective dye layers and the dye-receiving surface facing each other.
V, pulse width 16 msec. Dot density 6 dots / li
Recording was performed with a thermal head under the conditions of ne, and the results 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 xenon with a xenon fadeometer (Ci-35A, manufactured by Atlas).
Irradiation was performed at 0 KJ / m ² (integrated light amount of 420 nm), and the change in optical density before and after irradiation was measured with an optical densitometer (RD-918, manufactured by Macbeth Co., Ltd.), and the residual ratio of optical density was calculated by the following equation. . Residual rate (%) = {[optical density after irradiation] / [optical density before irradiation]} × 100 ◎; residual rate is 90% or more ○; residual rate is 80% or more and less than 90% △; residual rate is 70 % To less than 80% ×; Residual rate is less than 70% (2) Fingerprint resistance evaluation method After imprinting a fingerprint on the surface of the printed matter and leaving it at room temperature for 5 days,
The degree of discoloration and density change of the fingerprint imprinted part was visually evaluated. A: Almost no difference was observed between the fingerprint-printed area and the non-printed area. B: Discoloration or density change was observed. C: The fingerprint imprinted portion was white and the fingerprint shape was clearly recognized. D: White spots occurred around the fingerprint-printed area, and at the same time, aggregation of the dye was observed.

Comparative Example 1 A polymer was synthesized with the composition shown in Comparative Example No. 1 in Table 1 above, and an image-receiving sheet was produced, an image was formed, and an image was formed in the same manner as in Example 1 except that the polymer was used. Was evaluated. Comparative Example 2 A coating liquid having the same coating liquid composition as in Comparative Example 1 (without using a platinum-based catalyst) was allowed to stand at 60 ° C. for 24 hours, and then a predetermined amount of a platinum-based catalyst was added. Production of an image receiving sheet, formation of an image, and evaluation of the image were performed in the same manner as in Example 1. Comparative Example 3 A coating liquid having the same coating liquid composition as in Comparative Example 1 (without using a platinum-based catalyst) was allowed to stand at room temperature for 24 hours, and then a predetermined amount of a platinum-based catalyst was added. Production of an image receiving sheet, formation of an image, and evaluation of the image were performed in the same manner as in Example 1. Comparative Example 4 An image receiving sheet was manufactured in the same manner as in Comparative Example 1 using the same coating liquid as in Comparative Example 1, and the image receiving sheet was left in an oven at 60 ° C. for one week, and thereafter, image formation and image evaluation were performed. Was done.

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

Comparative Example 5 A polymer was synthesized with the composition shown in Comparative Example No. 2 in Table 1 above, and an image-receiving sheet was produced, an image was formed, and an image was formed in the same manner as in Example 1 except that the polymer was used. (Applied and dried immediately after the ink was formed, and printed immediately after the image receiving sheet was formed 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 image formation and image evaluation were performed. Comparative Example 7 In Comparative Example 5, an image receiving sheet was manufactured in the same manner as in Comparative Example 3, and the formation of this image and the evaluation of the image were performed. Comparative Example 8 An image receiving sheet was manufactured in the same manner as in Comparative Example 4 in Comparative Example 5, and formation of this image and evaluation of the image were performed.

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

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 the 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.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Jun Hasegawa 1-1-1 Kagacho, Ichigaya, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd. (56) References JP-A-3-23991 (JP, A) JP-A-4-52193 (JP, A) JP-A-4-1222693 (JP, A) JP-A-5-4459 (JP, A) JP-A-4-197786 (JP, A) JP-A-5-246155 ( JP, A) JP-A-61-102293 (JP, A) JP-A-3-19892 (JP, A) JP-A-4-299186 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) B41M 5/38-5/40

Claims (1)

(57) [Claims] 1. A thermal transfer image-receiving sheet having a dye-receiving layer formed on at least one surface of a base sheet, wherein the dye-receiving layer comprises an epoxy- containing addition-polymerizable monomer unit.
From a vinyl chloride-based copolymer resin containing 0.5 to 50 mol% , a catalyst-curable silicone oil and a platinum-based catalyst
A thermal transfer image-receiving sheet characterized by being formed .